| blob | 02a24c5fe65116f2bc6ba2cb0cd56a9fbbe96e5b |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2023 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
89 /* Nonzero if we are folding constants inside an initializer or a C++
90 manifestly-constant-evaluated context; zero otherwise.
91 Should be used when folding in initializer enables additional
92 optimizations. */
95 /* Nonzero if we are folding C++ manifestly-constant-evaluated context; zero
96 otherwise.
97 Should be used when certain constructs shouldn't be optimized
98 during folding in that context. */
101 /* The following constants represent a bit based encoding of GCC's
102 comparison operators. This encoding simplifies transformations
103 on relational comparison operators, such as AND and OR. */
121 };
154 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
155 Otherwise, return LOC. */
157 static location_t
159 {
162 }
164 /* Similar to protected_set_expr_location, but never modify x in place,
165 if location can and needs to be set, unshare it. */
167 tree
169 {
175 {
178 }
180 }
181 \f
182 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
183 division and returns the quotient. Otherwise returns
184 NULL_TREE. */
186 tree
188 {
189 widest_int quo;
196 }
197 \f
198 /* This is nonzero if we should defer warnings about undefined
199 overflow. This facility exists because these warnings are a
200 special case. The code to estimate loop iterations does not want
201 to issue any warnings, since it works with expressions which do not
202 occur in user code. Various bits of cleanup code call fold(), but
203 only use the result if it has certain characteristics (e.g., is a
204 constant); that code only wants to issue a warning if the result is
205 used. */
209 /* If a warning about undefined overflow is deferred, this is the
210 warning. Note that this may cause us to turn two warnings into
211 one, but that is fine since it is sufficient to only give one
212 warning per expression. */
216 /* If a warning about undefined overflow is deferred, this is the
217 level at which the warning should be emitted. */
221 /* Start deferring overflow warnings. We could use a stack here to
222 permit nested calls, but at present it is not necessary. */
224 void
226 {
228 }
230 /* Stop deferring overflow warnings. If there is a pending warning,
231 and ISSUE is true, then issue the warning if appropriate. STMT is
232 the statement with which the warning should be associated (used for
233 location information); STMT may be NULL. CODE is the level of the
234 warning--a warn_strict_overflow_code value. This function will use
235 the smaller of CODE and the deferred code when deciding whether to
236 issue the warning. CODE may be zero to mean to always use the
237 deferred code. */
239 void
241 {
243 location_t locus;
248 {
254 }
265 /* Use the smallest code level when deciding to issue the
266 warning. */
275 else
278 }
280 /* Stop deferring overflow warnings, ignoring any deferred
281 warnings. */
283 void
285 {
287 }
289 /* Whether we are deferring overflow warnings. */
291 bool
293 {
295 }
297 /* This is called when we fold something based on the fact that signed
298 overflow is undefined. */
300 void
302 {
304 {
307 {
310 }
311 }
314 }
315 \f
316 /* Return true if the built-in mathematical function specified by CODE
317 is odd, i.e. -f(x) == f(-x). */
319 bool
321 {
323 {
324 CASE_CFN_ASIN:
325 CASE_CFN_ASIN_FN:
326 CASE_CFN_ASINH:
327 CASE_CFN_ASINH_FN:
328 CASE_CFN_ATAN:
329 CASE_CFN_ATAN_FN:
330 CASE_CFN_ATANH:
331 CASE_CFN_ATANH_FN:
332 CASE_CFN_CASIN:
333 CASE_CFN_CASIN_FN:
334 CASE_CFN_CASINH:
335 CASE_CFN_CASINH_FN:
336 CASE_CFN_CATAN:
337 CASE_CFN_CATAN_FN:
338 CASE_CFN_CATANH:
339 CASE_CFN_CATANH_FN:
340 CASE_CFN_CBRT:
341 CASE_CFN_CBRT_FN:
342 CASE_CFN_CPROJ:
343 CASE_CFN_CPROJ_FN:
344 CASE_CFN_CSIN:
345 CASE_CFN_CSIN_FN:
346 CASE_CFN_CSINH:
347 CASE_CFN_CSINH_FN:
348 CASE_CFN_CTAN:
349 CASE_CFN_CTAN_FN:
350 CASE_CFN_CTANH:
351 CASE_CFN_CTANH_FN:
352 CASE_CFN_ERF:
353 CASE_CFN_ERF_FN:
354 CASE_CFN_LLROUND:
355 CASE_CFN_LLROUND_FN:
356 CASE_CFN_LROUND:
357 CASE_CFN_LROUND_FN:
358 CASE_CFN_ROUND:
359 CASE_CFN_ROUNDEVEN:
360 CASE_CFN_ROUNDEVEN_FN:
361 CASE_CFN_SIN:
362 CASE_CFN_SIN_FN:
363 CASE_CFN_SINH:
364 CASE_CFN_SINH_FN:
365 CASE_CFN_TAN:
366 CASE_CFN_TAN_FN:
367 CASE_CFN_TANH:
368 CASE_CFN_TANH_FN:
369 CASE_CFN_TRUNC:
370 CASE_CFN_TRUNC_FN:
373 CASE_CFN_LLRINT:
374 CASE_CFN_LLRINT_FN:
375 CASE_CFN_LRINT:
376 CASE_CFN_LRINT_FN:
377 CASE_CFN_NEARBYINT:
378 CASE_CFN_NEARBYINT_FN:
379 CASE_CFN_RINT:
380 CASE_CFN_RINT_FN:
385 }
387 }
389 /* Check whether we may negate an integer constant T without causing
390 overflow. */
392 bool
394 {
395 tree type;
404 }
406 /* Determine whether an expression T can be cheaply negated using
407 the function negate_expr without introducing undefined overflow. */
409 static bool
411 {
412 tree type;
421 {
426 /* Check that -CST will not overflow type. */
439 /* We want to canonicalize to positive real constants. Pretend
440 that only negative ones can be easily negated. */
448 {
452 /* Steps don't prevent negation. */
459 }
474 /* -(A + B) -> (-B) - A. */
477 /* -(A + B) -> (-A) - B. */
481 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
490 /* INT_MIN/n * n doesn't overflow while negating one operand it does
491 if n is a (negative) power of two. */
502 /* Fall through. */
515 /* In general we can't negate A in A / B, because if A is INT_MIN and
516 B is not 1 we change the sign of the result. */
520 /* In general we can't negate B in A / B, because if A is INT_MIN and
521 B is 1, we may turn this into INT_MIN / -1 which is undefined
522 and actually traps on some architectures. */
531 /* Negate -((double)float) as (double)(-float). */
533 {
537 }
541 /* Negate -f(x) as f(-x). */
547 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
549 {
553 }
558 }
560 }
562 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
563 simplification is possible.
564 If negate_expr_p would return true for T, NULL_TREE will never be
565 returned. */
567 static tree
569 {
571 tree tem;
574 {
575 /* Convert - (~A) to A + 1. */
599 {
604 }
608 {
609 tree_vector_builder elts;
613 {
618 }
621 }
644 {
645 /* -(A + B) -> (-B) - A. */
647 {
651 }
653 /* -(A + B) -> (-A) - B. */
655 {
659 }
660 }
664 /* - (A - B) -> B - A */
675 /* Fall through. */
679 {
688 }
696 /* In general we can't negate A in A / B, because if A is INT_MIN and
697 B is not 1 we change the sign of the result. */
703 /* In general we can't negate B in A / B, because if A is INT_MIN and
704 B is 1, we may turn this into INT_MIN / -1 which is undefined
705 and actually traps on some architectures. */
717 /* Convert -((double)float) into (double)(-float). */
719 {
723 }
727 /* Negate -f(x) as f(-x). */
730 {
736 }
740 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
742 {
745 {
752 }
753 }
758 }
761 }
763 /* A wrapper for fold_negate_expr_1. */
765 static tree
767 {
774 }
776 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
777 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
778 return NULL_TREE. */
780 static tree
782 {
784 location_t loc;
797 }
798 \f
799 /* Split a tree IN into a constant, literal and variable parts that could be
800 combined with CODE to make IN. "constant" means an expression with
801 TREE_CONSTANT but that isn't an actual constant. CODE must be a
802 commutative arithmetic operation. Store the constant part into *CONP,
803 the literal in *LITP and return the variable part. If a part isn't
804 present, set it to null. If the tree does not decompose in this way,
805 return the entire tree as the variable part and the other parts as null.
807 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
808 case, we negate an operand that was subtracted. Except if it is a
809 literal for which we use *MINUS_LITP instead.
811 If NEGATE_P is true, we are negating all of IN, again except a literal
812 for which we use *MINUS_LITP instead. If a variable part is of pointer
813 type, it is negated after converting to TYPE. This prevents us from
814 generating illegal MINUS pointer expression. LOC is the location of
815 the converted variable part.
817 If IN is itself a literal or constant, return it as appropriate.
819 Note that we do not guarantee that any of the three values will be the
820 same type as IN, but they will have the same signedness and mode. */
822 static tree
826 {
834 /* Strip any conversions that don't change the machine mode or signedness. */
843 /* We can associate addition and subtraction together (even
844 though the C standard doesn't say so) for integers because
845 the value is not affected. For reals, the value might be
846 affected, so we can't. */
852 {
858 /* First see if either of the operands is a literal, then a constant. */
871 /* If we haven't dealt with either operand, this is not a case we can
872 decompose. Otherwise, VAR is either of the ones remaining, if any. */
877 else
880 /* Now do any needed negations. */
887 }
892 {
893 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
894 when IN is constant. */
897 }
898 else
902 {
915 }
925 }
927 /* Re-associate trees split by the above function. T1 and T2 are
928 either expressions to associate or null. Return the new
929 expression, if any. LOC is the location of the new expression. If
930 we build an operation, do it in TYPE and with CODE. */
932 static tree
934 {
936 {
939 }
943 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
944 try to fold this since we will have infinite recursion. But do
945 deal with any NEGATE_EXPRs. */
949 {
951 {
964 }
966 {
969 }
973 }
977 }
978 \f
979 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
980 for use in int_const_binop, size_binop and size_diffop. */
982 static bool
984 {
991 {
1000 }
1005 }
1007 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
1008 a new constant in RES. Return FALSE if we don't know how to
1009 evaluate CODE at compile-time. */
1011 bool
1015 {
1016 wide_int tmp;
1019 {
1041 /* It's unclear from the C standard whether shifts can overflow.
1042 The following code ignores overflow; perhaps a C standard
1043 interpretation ruling is needed. */
1050 {
1054 else
1056 }
1057 else
1062 else
1141 }
1143 }
1145 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1146 produce a new constant in RES. Return FALSE if we don't know how
1147 to evaluate CODE at compile-time. */
1149 static bool
1153 {
1157 {
1175 else
1182 else
1195 }
1197 }
1199 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1200 produce a new constant. Return NULL_TREE if we don't know how to
1201 evaluate CODE at compile-time. */
1203 tree
1206 {
1207 poly_wide_int poly_res;
1213 {
1219 }
1228 }
1230 /* Return true if binary operation OP distributes over addition in operand
1231 OPNO, with the other operand being held constant. OPNO counts from 1. */
1233 static bool
1235 {
1237 {
1248 }
1249 }
1251 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1252 constant. We assume ARG1 and ARG2 have the same data type, or at least
1253 are the same kind of constant and the same machine mode. Return zero if
1254 combining the constants is not allowed in the current operating mode. */
1256 static tree
1258 {
1259 /* Sanity check for the recursive cases. */
1267 {
1273 }
1276 {
1277 machine_mode mode;
1278 REAL_VALUE_TYPE d1;
1279 REAL_VALUE_TYPE d2;
1280 REAL_VALUE_TYPE value;
1281 REAL_VALUE_TYPE result;
1285 /* The following codes are handled by real_arithmetic. */
1287 {
1298 }
1306 /* Don't perform operation if we honor signaling NaNs and
1307 either operand is a signaling NaN. */
1313 /* Don't perform operation if it would raise a division
1314 by zero exception. */
1320 /* If either operand is a NaN, just return it. Otherwise, set up
1321 for floating-point trap; we return an overflow. */
1323 {
1324 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1325 is off. */
1329 }
1331 {
1332 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1333 is off. */
1337 }
1342 /* Don't constant fold this floating point operation if
1343 both operands are not NaN but the result is NaN, and
1344 flag_trapping_math. Such operations should raise an
1345 invalid operation exception. */
1353 /* Don't constant fold this floating point operation if
1354 the result has overflowed and flag_trapping_math. */
1362 /* Don't constant fold this floating point operation if the
1363 result may dependent upon the run-time rounding mode and
1364 flag_rounding_math is set, or if GCC's software emulation
1365 is unable to accurately represent the result. */
1375 }
1378 {
1379 FIXED_VALUE_TYPE f1;
1380 FIXED_VALUE_TYPE f2;
1381 FIXED_VALUE_TYPE result;
1386 /* The following codes are handled by fixed_arithmetic. */
1388 {
1400 {
1407 }
1412 }
1419 /* Propagate overflow flags. */
1423 }
1426 {
1435 {
1446 mpc_mul);
1460 mpc_div);
1461 /* Fallthru. */
1467 {
1468 /* Keep this algorithm in sync with
1469 tree-complex.cc:expand_complex_div_straight().
1471 Expand complex division to scalars, straightforward algorithm.
1472 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1473 t = br*br + bi*bi
1474 */
1475 tree magsquared
1479 tree t1
1483 tree t2
1490 }
1491 else
1492 {
1493 /* Keep this algorithm in sync with
1494 tree-complex.cc:expand_complex_div_wide().
1496 Expand complex division to scalars, modified algorithm to minimize
1497 overflow with wide input ranges. */
1503 {
1504 /* In the TRUE branch, we compute
1505 ratio = br/bi;
1506 div = (br * ratio) + bi;
1507 tr = (ar * ratio) + ai;
1508 ti = (ai * ratio) - ar;
1509 tr = tr / div;
1510 ti = ti / div; */
1521 }
1522 else
1523 {
1524 /* In the FALSE branch, we compute
1525 ratio = d/c;
1526 divisor = (d * ratio) + c;
1527 tr = (b * ratio) + a;
1528 ti = b - (a * ratio);
1529 tr = tr / div;
1530 ti = ti / div; */
1542 }
1543 }
1548 }
1552 }
1558 {
1563 /* We can operate directly on the encoding if:
1565 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1566 implies
1567 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1569 Addition and subtraction are the supported operators
1570 for which this is true. */
1573 /* We can operate directly on stepped encodings if:
1575 a3 - a2 == a2 - a1
1576 implies:
1577 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1579 which is true if (x -> x op c) distributes over addition. */
1581 else
1582 /* Similarly in reverse. */
1584 tree_vector_builder elts;
1589 {
1595 /* It is possible that const_binop cannot handle the given
1596 code and return NULL_TREE */
1600 }
1603 }
1605 /* Shifts allow a scalar offset for a vector. */
1608 {
1611 tree_vector_builder elts;
1616 {
1621 /* It is possible that const_binop cannot handle the given
1622 code and return NULL_TREE. */
1626 }
1629 }
1631 }
1633 /* Overload that adds a TYPE parameter to be able to dispatch
1634 to fold_relational_const. */
1636 tree
1638 {
1642 /* ??? Until we make the const_binop worker take the type of the
1643 result as argument put those cases that need it here. */
1645 {
1662 {
1667 }
1673 {
1689 {
1694 ? NOP_EXPR
1701 }
1704 }
1710 {
1733 {
1746 }
1749 }
1752 }
1757 /* Make sure type and arg0 have the same saturating flag. */
1762 }
1764 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1765 Return zero if computing the constants is not possible. */
1767 tree
1769 {
1770 /* Don't perform the operation, other than NEGATE and ABS, if
1771 flag_signaling_nans is on and the operand is a signaling NaN. */
1781 {
1782 CASE_CONVERT:
1789 /* If the source address is 0, and the source address space
1790 cannot have a valid object at 0, fold to dest type null. */
1801 {
1802 /* Can't call fold_negate_const directly here as that doesn't
1803 handle all cases and we might not be able to negate some
1804 constants. */
1809 }
1819 {
1823 }
1831 /* Perform BIT_NOT_EXPR on each element individually. */
1833 {
1834 tree elem;
1836 /* This can cope with stepped encodings because ~x == -1 - x. */
1837 tree_vector_builder elements;
1841 {
1847 }
1850 }
1874 {
1897 else
1902 {
1908 }
1911 }
1920 }
1923 }
1925 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1926 indicates which particular sizetype to create. */
1928 tree
1930 {
1932 }
1933 \f
1934 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1935 is a tree code. The type of the result is taken from the operands.
1936 Both must be equivalent integer types, ala int_binop_types_match_p.
1937 If the operands are constant, so is the result. */
1939 tree
1941 {
1950 /* Handle the special case of two poly_int constants faster. */
1952 {
1953 /* And some specific cases even faster than that. */
1955 {
1962 }
1964 {
1968 }
1970 {
1974 }
1976 /* Handle general case of two integer constants. For sizetype
1977 constant calculations we always want to know about overflow,
1978 even in the unsigned case. */
1982 }
1985 }
1987 /* Given two values, either both of sizetype or both of bitsizetype,
1988 compute the difference between the two values. Return the value
1989 in signed type corresponding to the type of the operands. */
1991 tree
1993 {
1995 tree ctype;
2000 /* If the type is already signed, just do the simple thing. */
2008 else
2011 /* If either operand is not a constant, do the conversions to the signed
2012 type and subtract. The hardware will do the right thing with any
2013 overflow in the subtraction. */
2019 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2020 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2021 overflow) and negate (which can't either). Special-case a result
2022 of zero while we're here. */
2028 else
2032 MINUS_EXPR,
2034 }
2035 \f
2036 /* A subroutine of fold_convert_const handling conversions of an
2037 INTEGER_CST to another integer type. */
2039 static tree
2041 {
2042 /* Given an integer constant, make new constant with new type,
2043 appropriately sign-extended or truncated. Use widest_int
2044 so that any extension is done according ARG1's type. */
2048 }
2050 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2051 to an integer type. */
2053 static tree
2055 {
2057 tree t;
2059 /* The following code implements the floating point to integer
2060 conversion rules required by the Java Language Specification,
2061 that IEEE NaNs are mapped to zero and values that overflow
2062 the target precision saturate, i.e. values greater than
2063 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2064 are mapped to INT_MIN. These semantics are allowed by the
2065 C and C++ standards that simply state that the behavior of
2066 FP-to-integer conversion is unspecified upon overflow. */
2068 wide_int val;
2069 REAL_VALUE_TYPE r;
2073 {
2080 }
2082 /* If R is NaN, return zero and show we have an overflow. */
2084 {
2087 }
2089 /* See if R is less than the lower bound or greater than the
2090 upper bound. */
2093 {
2097 {
2100 }
2101 }
2104 {
2107 {
2110 {
2113 }
2114 }
2115 }
2122 }
2124 /* A subroutine of fold_convert_const handling conversions of a
2125 FIXED_CST to an integer type. */
2127 static tree
2129 {
2130 tree t;
2132 scalar_mode mode;
2134 /* Right shift FIXED_CST to temp by fbit. */
2138 {
2140 HOST_BITS_PER_DOUBLE_INT,
2143 /* Left shift temp to temp_trunc by fbit. */
2145 HOST_BITS_PER_DOUBLE_INT,
2147 }
2148 else
2149 {
2152 }
2154 /* If FIXED_CST is negative, we need to round the value toward 0.
2155 By checking if the fractional bits are not zero to add 1 to temp. */
2161 /* Given a fixed-point constant, make new constant with new type,
2162 appropriately sign-extended or truncated. */
2170 }
2172 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2173 to another floating point type. */
2175 static tree
2177 {
2178 REAL_VALUE_TYPE value;
2179 tree t;
2181 /* If the underlying modes are the same, simply treat it as
2182 copy and rebuild with TREE_REAL_CST information and the
2183 given type. */
2185 {
2188 }
2190 /* Don't perform the operation if flag_signaling_nans is on
2191 and the operand is a signaling NaN. */
2196 /* With flag_rounding_math we should respect the current rounding mode
2197 unless the conversion is exact. */
2205 /* If converting an infinity or NAN to a representation that doesn't
2206 have one, set the overflow bit so that we can produce some kind of
2207 error message at the appropriate point if necessary. It's not the
2208 most user-friendly message, but it's better than nothing. */
2215 /* Regular overflow, conversion produced an infinity in a mode that
2216 can't represent them. */
2221 else
2224 }
2226 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2227 to a floating point type. */
2229 static tree
2231 {
2232 REAL_VALUE_TYPE value;
2233 tree t;
2241 }
2243 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2244 to another fixed-point type. */
2246 static tree
2248 {
2249 FIXED_VALUE_TYPE value;
2250 tree t;
2257 /* Propagate overflow flags. */
2261 }
2263 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2264 to a fixed-point type. */
2266 static tree
2268 {
2269 FIXED_VALUE_TYPE value;
2270 tree t;
2272 double_int di;
2279 else
2287 /* Propagate overflow flags. */
2291 }
2293 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2294 to a fixed-point type. */
2296 static tree
2298 {
2299 FIXED_VALUE_TYPE value;
2300 tree t;
2308 /* Propagate overflow flags. */
2312 }
2314 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2315 type TYPE. If no simplification can be done return NULL_TREE. */
2317 static tree
2319 {
2324 /* We can't widen types, since the runtime value could overflow the
2325 original type before being extended to the new type. */
2336 {
2343 }
2345 {
2347 {
2349 /* Avoid the folding if flag_rounding_math is on and the
2350 conversion is not exact. */
2352 {
2358 }
2360 }
2365 }
2367 {
2374 }
2376 {
2379 {
2382 /* We can't handle steps directly when extending, since the
2383 values need to wrap at the original precision first. */
2384 bool step_ok_p
2388 tree_vector_builder v;
2393 {
2399 }
2401 }
2402 }
2404 }
2406 /* Construct a vector of zero elements of vector type TYPE. */
2408 static tree
2410 {
2411 tree t;
2415 }
2417 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2419 bool
2421 {
2436 {
2458 }
2459 }
2461 /* Convert expression ARG to type TYPE. Used by the middle-end for
2462 simple conversions in preference to calling the front-end's convert. */
2464 tree
2466 {
2468 tree tem;
2479 {
2482 /* Handle conversions between pointers to different address spaces. */
2487 /* fall through */
2492 {
2496 }
2510 {
2514 }
2516 {
2520 }
2522 {
2526 }
2529 {
2547 }
2552 {
2556 }
2559 {
2573 }
2577 {
2586 integer_zero_node));
2588 {
2592 {
2598 }
2606 }
2610 }
2628 }
2629 fold_convert_exit:
2632 }
2633 \f
2634 /* Return false if expr can be assumed not to be an lvalue, true
2635 otherwise. */
2637 static bool
2639 {
2640 /* We only need to wrap lvalue tree codes. */
2642 {
2674 /* Assume the worst for front-end tree codes. */
2678 }
2681 }
2683 /* Return an expr equal to X but certainly not valid as an lvalue. */
2685 tree
2687 {
2688 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2689 us. */
2696 }
2697 \f
2698 /* Given a tree comparison code, return the code that is the logical inverse.
2699 It is generally not safe to do this for floating-point comparisons, except
2700 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2701 ERROR_MARK in this case. */
2703 enum tree_code
2705 {
2711 {
2742 }
2743 }
2745 /* Similar, but return the comparison that results if the operands are
2746 swapped. This is safe for floating-point. */
2748 enum tree_code
2750 {
2752 {
2778 }
2779 }
2782 /* Convert a comparison tree code from an enum tree_code representation
2783 into a compcode bit-based encoding. This function is the inverse of
2784 compcode_to_comparison. */
2786 static enum comparison_code
2788 {
2790 {
2821 }
2822 }
2824 /* Convert a compcode bit-based encoding of a comparison operator back
2825 to GCC's enum tree_code representation. This function is the
2826 inverse of comparison_to_compcode. */
2828 static enum tree_code
2830 {
2832 {
2863 }
2864 }
2866 /* Return true if COND1 tests the opposite condition of COND2. */
2868 bool
2870 {
2873 && (invert_tree_comparison
2880 }
2882 /* Return a tree for the comparison which is the combination of
2883 doing the AND or OR (depending on CODE) of the two operations LCODE
2884 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2885 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2886 if this makes the transformation invalid. */
2888 tree
2893 {
2900 {
2911 }
2914 {
2915 /* Eliminate unordered comparisons, as well as LTGT and ORD
2916 which are not used unless the mode has NaNs. */
2922 }
2924 {
2925 /* Check that the original operation and the optimized ones will trap
2926 under the same condition. */
2937 /* In a short-circuited boolean expression the LHS might be
2938 such that the RHS, if evaluated, will never trap. For
2939 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2940 if neither x nor y is NaN. (This is a mixed blessing: for
2941 example, the expression above will never trap, hence
2942 optimizing it to x < y would be invalid). */
2947 /* If the comparison was short-circuited, and only the RHS
2948 trapped, we may now generate a spurious trap. */
2953 /* If we changed the conditions that cause a trap, we lose. */
2956 }
2962 else
2963 {
2968 }
2969 }
2970 \f
2971 /* Return nonzero if two operands (typically of the same tree node)
2972 are necessarily equal. FLAGS modifies behavior as follows:
2974 If OEP_ONLY_CONST is set, only return nonzero for constants.
2975 This function tests whether the operands are indistinguishable;
2976 it does not test whether they are equal using C's == operation.
2977 The distinction is important for IEEE floating point, because
2978 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2979 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2981 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2982 even though it may hold multiple values during a function.
2983 This is because a GCC tree node guarantees that nothing else is
2984 executed between the evaluation of its "operands" (which may often
2985 be evaluated in arbitrary order). Hence if the operands themselves
2986 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2987 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2988 unset means assuming isochronic (or instantaneous) tree equivalence.
2989 Unless comparing arbitrary expression trees, such as from different
2990 statements, this flag can usually be left unset.
2992 If OEP_PURE_SAME is set, then pure functions with identical arguments
2993 are considered the same. It is used when the caller has other ways
2994 to ensure that global memory is unchanged in between.
2996 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2997 not values of expressions.
2999 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
3000 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
3002 If OEP_BITWISE is set, then require the values to be bitwise identical
3003 rather than simply numerically equal. Do not take advantage of things
3004 like math-related flags or undefined behavior; only return true for
3005 values that are provably bitwise identical in all circumstances.
3007 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
3008 any operand with side effect. This is unnecesarily conservative in the
3009 case we know that arg0 and arg1 are in disjoint code paths (such as in
3010 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
3011 addresses with TREE_CONSTANT flag set so we know that &var == &var
3012 even if var is volatile. */
3014 bool
3017 {
3025 /* If either is ERROR_MARK, they aren't equal. */
3031 /* Similar, if either does not have a type (like a template id),
3032 they aren't equal. */
3036 /* Bitwise identity makes no sense if the values have different layouts. */
3041 /* We cannot consider pointers to different address space equal. */
3048 /* Check equality of integer constants before bailing out due to
3049 precision differences. */
3051 {
3052 /* Address of INTEGER_CST is not defined; check that we did not forget
3053 to drop the OEP_ADDRESS_OF flags. */
3056 }
3059 {
3060 /* If both types don't have the same signedness, then we can't consider
3061 them equal. We must check this before the STRIP_NOPS calls
3062 because they may change the signedness of the arguments. As pointers
3063 strictly don't have a signedness, require either two pointers or
3064 two non-pointers as well. */
3070 /* If both types don't have the same precision, then it is not safe
3071 to strip NOPs. */
3078 }
3079 #if 0
3080 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3081 sanity check once the issue is solved. */
3082 else
3083 /* Addresses of conversions and SSA_NAMEs (and many other things)
3084 are not defined. Check that we did not forget to drop the
3085 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3088 #endif
3090 /* In case both args are comparisons but with different comparison
3091 code, try to swap the comparison operands of one arg to produce
3092 a match and compare that variant. */
3096 {
3104 }
3107 {
3108 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3110 ;
3112 {
3113 /* If we are interested in comparing addresses ignore
3114 MEM_REF wrappings of the base that can appear just for
3115 TBAA reasons. */
3129 }
3130 else
3132 }
3134 /* When not checking adddresses, this is needed for conversions and for
3135 COMPONENT_REF. Might as well play it safe and always test this. */
3142 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3143 We don't care about side effects in that case because the SAVE_EXPR
3144 takes care of that for us. In all other cases, two expressions are
3145 equal if they have no side effects. If we have two identical
3146 expressions with side effects that should be treated the same due
3147 to the only side effects being identical SAVE_EXPR's, that will
3148 be detected in the recursive calls below.
3149 If we are taking an invariant address of two identical objects
3150 they are necessarily equal as well. */
3157 /* Next handle constant cases, those for which we can return 1 even
3158 if ONLY_CONST is set. */
3161 {
3174 {
3175 /* If we do not distinguish between signed and unsigned zero,
3176 consider them equal. */
3179 }
3183 {
3198 }
3202 flags)
3204 flags));
3215 flags | OEP_ADDRESS_OF
3218 /* In GIMPLE empty constructors are allowed in initializers of
3219 aggregates. */
3223 }
3225 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3226 two instances of undefined behavior will give identical results. */
3230 /* Define macros to test an operand from arg0 and arg1 for equality and a
3231 variant that allows null and views null as being different from any
3232 non-null value. In the latter case, if either is null, the both
3233 must be; otherwise, do the normal comparison. */
3234 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3235 TREE_OPERAND (arg1, N), flags)
3237 #define OP_SAME_WITH_NULL(N) \
3238 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3239 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3242 {
3244 /* Two conversions are equal only if signedness and modes match. */
3246 {
3247 CASE_CONVERT:
3255 }
3265 /* For commutative ops, allow the other order. */
3273 /* If either of the pointer (or reference) expressions we are
3274 dereferencing contain a side effect, these cannot be equal,
3275 but their addresses can be. */
3282 {
3285 {
3289 /* Verify that the access types are compatible. */
3293 }
3298 /* Require the same offset. */
3304 /* Fallthru. */
3312 {
3313 /* Require equal access sizes */
3319 flags)))
3321 /* Verify that access happens in similar types. */
3324 /* Verify that accesses are TBAA compatible. */
3333 /* Verify that alignment is compatible. */
3337 }
3340 /* TARGET_MEM_REF require equal extra operands. */
3351 /* Compare the array index by value if it is constant first as we
3352 may have different types but same value here. */
3358 /* Compare low bound and element size as with OEP_ADDRESS_OF
3359 we have to account for the offset of the ref. */
3364 array_ref_low_bound
3368 array_ref_element_size
3370 flags))));
3373 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3374 may be NULL when we're called to compare MEM_EXPRs. */
3377 {
3380 /* Most of time we only need to compare FIELD_DECLs for equality.
3381 However when determining address look into actual offsets.
3382 These may match for unions and unshared record types. */
3385 {
3388 {
3392 /* Non-FIELD_DECL operands can appear in C++ templates. */
3399 flags))
3401 }
3402 else
3404 }
3405 }
3416 }
3420 {
3422 /* Be sure we pass right ADDRESS_OF flag. */
3439 /* The multiplcation operands are commutative. */
3440 /* FALLTHRU */
3448 /* Otherwise take into account this is a commutative operation. */
3461 /* BIT_INSERT_EXPR has an implict operand as the type precision
3462 of op1. Need to check to make sure they are the same. */
3468 /* FALLTHRU */
3493 /* Virtual table reference. */
3505 {
3510 }
3515 }
3519 {
3523 /* If not both CALL_EXPRs are either internal or normal function
3524 functions, then they are not equal. */
3527 {
3528 /* If the CALL_EXPRs call different internal functions, then they
3529 are not equal. */
3532 }
3533 else
3534 {
3535 /* If the CALL_EXPRs call different functions, then they are not
3536 equal. */
3538 flags))
3540 }
3542 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3543 {
3547 else
3551 }
3553 /* Now see if all the arguments are the same. */
3554 {
3565 /* If we get here and both argument lists are exhausted
3566 then the CALL_EXPRs are equal. */
3568 }
3571 }
3574 /* Consider __builtin_sqrt equal to sqrt. */
3584 {
3585 /* Consider decls with the same name equal. The caller needs
3586 to make sure they refer to the same entity (such as a function
3587 formal parameter). */
3593 }
3598 {
3602 /* In GIMPLE constructors are used only to build vectors from
3603 elements. Individual elements in the constructor must be
3604 indexed in increasing order and form an initial sequence.
3606 We make no effort to compare constructors in generic.
3607 (see sem_variable::equals in ipa-icf which can do so for
3608 constants). */
3613 /* Be sure that vectors constructed have the same representation.
3614 We only tested element precision and modes to match.
3615 Vectors may be BLKmode and thus also check that the number of
3616 parts match. */
3629 {
3634 /* In GIMPLE the indexes can be either NULL or matching i.
3635 Double check this so we won't get false
3636 positives for GENERIC. */
3644 }
3646 }
3649 {
3650 /* Compare the STATEMENT_LISTs. */
3656 {
3657 /* The lists don't have the same number of statements. */
3663 flags & (OEP_LEXICOGRAPHIC
3666 }
3667 }
3672 {
3683 }
3687 }
3689 #undef OP_SAME
3690 #undef OP_SAME_WITH_NULL
3691 }
3693 /* Generate a hash value for an expression. This can be used iteratively
3694 by passing a previous result as the HSTATE argument. */
3696 void
3699 {
3705 {
3708 }
3718 {
3719 /* Alas, constants aren't shared, so we can't rely on pointer
3720 identity. */
3730 {
3734 else
3738 }
3740 {
3744 }
3754 {
3761 }
3763 /* We can just compare by pointer. */
3767 /* The node itself doesn't matter. */
3771 /* Ignore. */
3774 /* A list of expressions, for a CALL_EXPR or as the elements of a
3775 VECTOR_CST. */
3780 {
3786 {
3787 /* In GIMPLE the indexes can be either NULL or matching i. */
3792 }
3794 }
3796 {
3797 tree_stmt_iterator i;
3802 }
3811 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3812 Otherwise nodes that compare equal according to operand_equal_p might
3813 get different hash codes. However, don't do this for machine specific
3814 or front end builtins, since the function code is overloaded in those
3815 cases. */
3818 {
3821 }
3822 /* FALL THROUGH */
3825 {
3829 }
3833 {
3834 /* DECL's have a unique ID */
3836 }
3838 {
3839 /* For comparisons that can be swapped, use the lower
3840 tree code. */
3847 }
3849 {
3850 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3851 operand_equal_p. */
3855 /* Don't hash the type, that can lead to having nodes which
3856 compare equal according to operand_equal_p, but which
3857 have different hash codes. Make sure to include signedness
3858 in the hash computation. */
3861 }
3862 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3870 /* Don't ICE on FE specific trees, or their arguments etc.
3871 during operand_equal_p hash verification. */
3874 else
3875 {
3881 {
3897 {
3904 }
3918 {
3919 /* The multiplication operands are commutative. */
3926 }
3934 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3935 Usually different TARGET_EXPRs just should use
3936 different temporaries in their slots. */
3941 /* Virtual table reference. */
3949 {
3951 /* We compute mangled names only when free_lang_data is run.
3952 In that case we can hash precisely. */
3955 hstate.add_object
3956 (IDENTIFIER_HASH_VALUE
3958 }
3962 }
3964 /* Don't hash the type, that can lead to having nodes which
3965 compare equal according to operand_equal_p, but which
3966 have different hash codes. */
3968 {
3969 /* Make sure to include signness in the hash computation. */
3972 }
3975 {
3976 /* It's a commutative expression. We want to hash it the same
3977 however it appears. We do this by first hashing both operands
3978 and then rehashing based on the order of their independent
3979 hashes. */
3984 }
3985 else
3989 }
3991 }
3992 }
3994 bool
3997 {
3998 /* When checking and unless comparing DECL names, verify that if
3999 the outermost operand_equal_p call returns non-zero then ARG0
4000 and ARG1 have the same hash value. */
4002 {
4004 {
4006 {
4013 }
4015 }
4016 else
4020 }
4023 }
4028 /* Conveinece wrapper around operand_compare class because usually we do
4029 not need to play with the valueizer. */
4031 bool
4033 {
4035 }
4037 namespace inchash
4038 {
4040 /* Generate a hash value for an expression. This can be used iteratively
4041 by passing a previous result as the HSTATE argument.
4043 This function is intended to produce the same hash for expressions which
4044 would compare equal using operand_equal_p. */
4045 void
4047 {
4049 }
4051 }
4052 \f
4053 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
4054 with a different signedness or a narrower precision. */
4056 static bool
4058 {
4066 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4067 and see if the inner values are the same. This removes any
4068 signedness comparison, which doesn't matter here. */
4076 /* Discard a single widening conversion from ARG1 and see if the inner
4077 value is the same as ARG0. */
4086 }
4087 \f
4088 /* See if ARG is an expression that is either a comparison or is performing
4089 arithmetic on comparisons. The comparisons must only be comparing
4090 two different values, which will be stored in *CVAL1 and *CVAL2; if
4091 they are nonzero it means that some operands have already been found.
4092 No variables may be used anywhere else in the expression except in the
4093 comparisons.
4095 If this is true, return 1. Otherwise, return zero. */
4097 static bool
4099 {
4103 /* We can handle some of the tcc_expression cases here. */
4112 {
4131 /* First see if we can handle the first operand, then the second. For
4132 the second operand, we know *CVAL1 can't be zero. It must be that
4133 one side of the comparison is each of the values; test for the
4134 case where this isn't true by failing if the two operands
4135 are the same. */
4144 ;
4148 ;
4149 else
4153 ;
4157 ;
4158 else
4165 }
4166 }
4167 \f
4168 /* ARG is a tree that is known to contain just arithmetic operations and
4169 comparisons. Evaluate the operations in the tree substituting NEW0 for
4170 any occurrence of OLD0 as an operand of a comparison and likewise for
4171 NEW1 and OLD1. */
4173 static tree
4176 {
4181 /* We can handle some of the tcc_expression cases here. */
4189 {
4204 {
4223 }
4224 /* Fall through - ??? */
4227 {
4231 /* We need to check both for exact equality and tree equality. The
4232 former will be true if the operand has a side-effect. In that
4233 case, we know the operand occurred exactly once. */
4246 }
4250 }
4251 }
4252 \f
4253 /* Return a tree for the case when the result of an expression is RESULT
4254 converted to TYPE and OMITTED was previously an operand of the expression
4255 but is now not needed (e.g., we folded OMITTED * 0).
4257 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4258 the conversion of RESULT to TYPE. */
4260 tree
4262 {
4265 /* If the resulting operand is an empty statement, just return the omitted
4266 statement casted to void. */
4276 }
4278 /* Return a tree for the case when the result of an expression is RESULT
4279 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4280 of the expression but are now not needed.
4282 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4283 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4284 evaluated before OMITTED2. Otherwise, if neither has side effects,
4285 just do the conversion of RESULT to TYPE. */
4287 tree
4290 {
4299 }
4301 \f
4302 /* Return a simplified tree node for the truth-negation of ARG. This
4303 never alters ARG itself. We assume that ARG is an operation that
4304 returns a truth value (0 or 1).
4306 FIXME: one would think we would fold the result, but it causes
4307 problems with the dominator optimizer. */
4309 static tree
4311 {
4316 /* If this is a comparison, we can simply invert it, except for
4317 floating-point non-equality comparisons, in which case we just
4318 enclose a TRUTH_NOT_EXPR around what we have. */
4321 {
4324 && flag_trapping_math
4337 }
4340 {
4359 /* Here we can invert either operand. We invert the first operand
4360 unless the second operand is a TRUTH_NOT_EXPR in which case our
4361 result is the XOR of the first operand with the inside of the
4362 negation of the second operand. */
4367 else
4390 {
4397 /* A COND_EXPR may have a throw as one operand, which
4398 then has void type. Just leave void operands
4399 as they are. */
4405 }
4417 CASE_CONVERT:
4421 /* fall through */
4443 }
4444 }
4446 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4447 assume that ARG is an operation that returns a truth value (0 or 1
4448 for scalars, 0 or -1 for vectors). Return the folded expression if
4449 folding is successful. Otherwise, return NULL_TREE. */
4451 static tree
4453 {
4456 ? BIT_NOT_EXPR
4459 }
4461 /* Return a simplified tree node for the truth-negation of ARG. This
4462 never alters ARG itself. We assume that ARG is an operation that
4463 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4465 tree
4467 {
4473 ? BIT_NOT_EXPR
4476 }
4477 \f
4478 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4479 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4480 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4481 is the original memory reference used to preserve the alias set of
4482 the access. */
4484 static tree
4488 {
4491 /* Attempt not to lose the access path if possible. */
4493 {
4495 machine_mode nmode;
4497 tree noffset;
4505 && !reversep
4506 && !nreversep
4508 {
4511 }
4512 }
4521 {
4528 }
4543 }
4545 /* Optimize a bit-field compare.
4547 There are two cases: First is a compare against a constant and the
4548 second is a comparison of two items where the fields are at the same
4549 bit position relative to the start of a chunk (byte, halfword, word)
4550 large enough to contain it. In these cases we can avoid the shift
4551 implicit in bitfield extractions.
4553 For constants, we emit a compare of the shifted constant with the
4554 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4555 compared. For two fields at the same position, we do the ANDs with the
4556 similar mask and compare the result of the ANDs.
4558 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4559 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4560 are the left and right operands of the comparison, respectively.
4562 If the optimization described above can be done, we return the resulting
4563 tree. Otherwise we return zero. */
4565 static tree
4568 {
4572 tree unsigned_type;
4575 scalar_int_mode nmode;
4580 tree mask;
4581 tree offset;
4583 /* Get all the information about the extractions being done. If the bit size
4584 is the same as the size of the underlying object, we aren't doing an
4585 extraction at all and so can do nothing. We also don't want to
4586 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4587 then will no longer be able to replace it. */
4602 else
4603 {
4604 /* If this is not a constant, we can only do something if bit positions,
4605 sizes, signedness and storage order are the same. */
4606 rinner
4619 }
4621 /* Honor the C++ memory model and mimic what RTL expansion does. */
4625 {
4629 }
4631 /* See if we can find a mode to refer to this field. We should be able to,
4632 but fail if we can't. */
4640 /* Set signed and unsigned types of the precision of this mode for the
4641 shifts below. */
4644 /* Compute the bit position and size for the new reference and our offset
4645 within it. If the new reference is the same size as the original, we
4646 won't optimize anything, so return zero. */
4656 /* Make the mask to be used against the extracted field. */
4663 {
4667 /* If not comparing with constant, just rework the comparison
4668 and return. */
4676 }
4678 /* Otherwise, we are handling the constant case. See if the constant is too
4679 big for the field. Warn and return a tree for 0 (false) if so. We do
4680 this not only for its own sake, but to avoid having to test for this
4681 error case below. If we didn't, we might generate wrong code.
4683 For unsigned fields, the constant shifted right by the field length should
4684 be all zero. For signed fields, the high-order bits should agree with
4685 the sign bit. */
4688 {
4690 {
4694 }
4695 }
4696 else
4697 {
4700 {
4704 }
4705 }
4710 /* Single-bit compares should always be against zero. */
4712 {
4715 }
4717 /* Make a new bitfield reference, shift the constant over the
4718 appropriate number of bits and mask it with the computed mask
4719 (in case this was a signed field). If we changed it, make a new one. */
4727 mask);
4732 }
4733 \f
4734 /* Subroutine for fold_truth_andor_1: decode a field reference.
4736 If EXP is a comparison reference, we return the innermost reference.
4738 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4739 set to the starting bit number.
4741 If the innermost field can be completely contained in a mode-sized
4742 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4744 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4745 otherwise it is not changed.
4747 *PUNSIGNEDP is set to the signedness of the field.
4749 *PREVERSEP is set to the storage order of the field.
4751 *PMASK is set to the mask used. This is either contained in a
4752 BIT_AND_EXPR or derived from the width of the field.
4754 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4756 Return 0 if this is not a component reference or is one that we can't
4757 do anything with. */
4759 static tree
4764 {
4769 tree unsigned_type;
4772 /* All the optimizations using this function assume integer fields.
4773 There are problems with FP fields since the type_for_size call
4774 below can fail for, e.g., XFmode. */
4778 /* We are interested in the bare arrangement of bits, so strip everything
4779 that doesn't affect the machine mode. However, record the type of the
4780 outermost expression if it may matter below. */
4787 {
4793 }
4804 /* Reject out-of-bound accesses (PR79731). */
4816 /* If the number of bits in the reference is the same as the bitsize of
4817 the outer type, then the outer type gives the signedness. Otherwise
4818 (in case of a small bitfield) the signedness is unchanged. */
4822 /* Compute the mask to access the bitfield. */
4830 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4838 }
4840 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4841 bit positions and MASK is SIGNED. */
4843 static bool
4845 {
4849 /* If this function returns true when the type of the mask is
4850 UNSIGNED, then there will be errors. In particular see
4851 gcc.c-torture/execute/990326-1.c. There does not appear to be
4852 any documentation paper trail as to why this is so. But the pre
4853 wide-int worked with that restriction and it has been preserved
4854 here. */
4859 }
4861 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4862 represents the sign bit of EXP's type. If EXP represents a sign
4863 or zero extension, also test VAL against the unextended type.
4864 The return value is the (sub)expression whose sign bit is VAL,
4865 or NULL_TREE otherwise. */
4867 tree
4869 {
4871 tree t;
4873 /* Tree EXP must have an integral type. */
4878 /* Tree VAL must be an integer constant. */
4887 /* Handle extension from a narrower type. */
4893 }
4895 /* Subroutine for fold_truth_andor_1 and simple_condition_p: determine if an
4896 operand is simple enough to be evaluated unconditionally. */
4898 static bool
4900 {
4901 /* Strip any conversions that don't change the machine mode. */
4910 /* Don't regard global variables as simple. They may be
4911 allocated in ways unknown to the compiler (shared memory,
4912 #pragma weak, etc). */
4915 /* Weakrefs are not safe to be read, since they can be NULL.
4916 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4917 have DECL_WEAK flag set. */
4919 /* Loading a static variable is unduly expensive, but global
4920 registers aren't expensive. */
4922 }
4924 /* Determine if an operand is simple enough to be evaluated unconditionally.
4925 In addition to simple_operand_p, we assume that comparisons, conversions,
4926 and logic-not operations are simple, if their operands are simple, too. */
4928 bool
4930 {
4949 }
4951 \f
4952 /* The following functions are subroutines to fold_range_test and allow it to
4953 try to change a logical combination of comparisons into a range test.
4955 For example, both
4956 X == 2 || X == 3 || X == 4 || X == 5
4957 and
4958 X >= 2 && X <= 5
4959 are converted to
4960 (unsigned) (X - 2) <= 3
4962 We describe each set of comparisons as being either inside or outside
4963 a range, using a variable named like IN_P, and then describe the
4964 range with a lower and upper bound. If one of the bounds is omitted,
4965 it represents either the highest or lowest value of the type.
4967 In the comments below, we represent a range by two numbers in brackets
4968 preceded by a "+" to designate being inside that range, or a "-" to
4969 designate being outside that range, so the condition can be inverted by
4970 flipping the prefix. An omitted bound is represented by a "-". For
4971 example, "- [-, 10]" means being outside the range starting at the lowest
4972 possible value and ending at 10, in other words, being greater than 10.
4973 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4974 always false.
4976 We set up things so that the missing bounds are handled in a consistent
4977 manner so neither a missing bound nor "true" and "false" need to be
4978 handled using a special case. */
4980 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4981 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4982 and UPPER1_P are nonzero if the respective argument is an upper bound
4983 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4984 must be specified for a comparison. ARG1 will be converted to ARG0's
4985 type if both are specified. */
4987 static tree
4990 {
4991 tree tem;
4995 /* If neither arg represents infinity, do the normal operation.
4996 Else, if not a comparison, return infinity. Else handle the special
4997 comparison rules. Note that most of the cases below won't occur, but
4998 are handled for consistency. */
5001 {
5006 }
5011 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
5012 for neither. In real maths, we cannot assume open ended ranges are
5013 the same. But, this is computer arithmetic, where numbers are finite.
5014 We can therefore make the transformation of any unbounded range with
5015 the value Z, Z being greater than any representable number. This permits
5016 us to treat unbounded ranges as equal. */
5020 {
5041 }
5044 }
5045 \f
5046 /* Helper routine for make_range. Perform one step for it, return
5047 new expression if the loop should continue or NULL_TREE if it should
5048 stop. */
5050 tree
5054 {
5060 {
5062 /* We can only do something if the range is testing for zero. */
5071 /* We can only do something if the range is testing for zero
5072 and if the second operand is an integer constant. Note that
5073 saying something is "in" the range we make is done by
5074 complementing IN_P since it will set in the initial case of
5075 being not equal to zero; "out" is leaving it alone. */
5082 {
5103 }
5105 /* If this is an unsigned comparison, we also know that EXP is
5106 greater than or equal to zero. We base the range tests we make
5107 on that fact, so we record it here so we can parse existing
5108 range tests. We test arg0_type since often the return type
5109 of, e.g. EQ_EXPR, is boolean. */
5111 {
5115 NULL_TREE))
5120 /* If the high bound is missing, but we have a nonzero low
5121 bound, reverse the range so it goes from zero to the low bound
5122 minus 1. */
5124 {
5129 }
5130 }
5138 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5139 low and high are non-NULL, then normalize will DTRT. */
5142 {
5147 }
5149 /* (-x) IN [a,b] -> x in [-b, -a] */
5161 /* ~ X -> -X - 1 */
5170 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5171 move a constant to the other side. */
5176 /* If EXP is signed, any overflow in the computation is undefined,
5177 so we don't worry about it so long as our computations on
5178 the bounds don't overflow. For unsigned, overflow is defined
5179 and this is exactly the right thing. */
5191 normalize:
5192 /* Check for an unsigned range which has wrapped around the maximum
5193 value thus making n_high < n_low, and normalize it. */
5195 {
5201 /* If the range is of the form +/- [ x+1, x ], we won't
5202 be able to normalize it. But then, it represents the
5203 whole range or the empty set, so make it
5204 +/- [ -, - ]. */
5208 else
5210 }
5211 else
5219 CASE_CONVERT:
5237 /* If we're converting arg0 from an unsigned type, to exp,
5238 a signed type, we will be doing the comparison as unsigned.
5239 The tests above have already verified that LOW and HIGH
5240 are both positive.
5242 So we have to ensure that we will handle large unsigned
5243 values the same way that the current signed bounds treat
5244 negative values. */
5247 {
5248 tree high_positive;
5249 tree equiv_type;
5250 /* For fixed-point modes, we need to pass the saturating flag
5251 as the 2nd parameter. */
5253 equiv_type
5256 else
5257 equiv_type
5260 /* A range without an upper bound is, naturally, unbounded.
5261 Since convert would have cropped a very large value, use
5262 the max value for the destination type. */
5263 high_positive
5270 high_positive),
5273 /* If the low bound is specified, "and" the range with the
5274 range for which the original unsigned value will be
5275 positive. */
5277 {
5280 integer_zero_node),
5281 high_positive))
5285 }
5286 else
5287 {
5288 /* Otherwise, "or" the range with the range of the input
5289 that will be interpreted as negative. */
5292 integer_zero_node),
5293 high_positive))
5297 }
5298 }
5300 /* Otherwise, if we are converting arg0 from signed type, to exp,
5301 an unsigned type, we will do the comparison as signed. If
5302 high is non-NULL, we punt above if it doesn't fit in the signed
5303 type, so if we get through here, +[-, high] or +[low, high] are
5304 equivalent to +[-, n_high] or +[n_low, n_high]. Similarly,
5305 +[-, -] or -[-, -] are equivalent too. But if low is specified and
5306 high is not, the +[low, -] range is equivalent to union of
5307 +[n_low, -] and +[-, -1] ranges, so +[low, -] is equivalent to
5308 -[0, n_low-1] and similarly -[low, -] to +[0, n_low-1], except for
5309 low being 0, which should be treated as [-, -]. */
5312 && low
5314 {
5317 else
5318 {
5323 }
5324 }
5333 }
5334 }
5336 /* Given EXP, a logical expression, set the range it is testing into
5337 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5338 actually being tested. *PLOW and *PHIGH will be made of the same
5339 type as the returned expression. If EXP is not a comparison, we
5340 will most likely not be returning a useful value and range. Set
5341 *STRICT_OVERFLOW_P to true if the return value is only valid
5342 because signed overflow is undefined; otherwise, do not change
5343 *STRICT_OVERFLOW_P. */
5345 tree
5348 {
5356 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5357 and see if we can refine the range. Some of the cases below may not
5358 happen, but it doesn't seem worth worrying about this. We "continue"
5359 the outer loop when we've changed something; otherwise we "break"
5360 the switch, which will "break" the while. */
5366 {
5372 {
5380 }
5389 }
5391 /* If EXP is a constant, we can evaluate whether this is true or false. */
5393 {
5400 }
5404 }
5406 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5407 a bitwise check i.e. when
5408 LOW == 0xXX...X00...0
5409 HIGH == 0xXX...X11...1
5410 Return corresponding mask in MASK and stem in VALUE. */
5412 static bool
5415 {
5438 }
5439 \f
5440 /* Helper routine for build_range_check and match.pd. Return the type to
5441 perform the check or NULL if it shouldn't be optimized. */
5443 tree
5445 {
5446 /* First make sure that arithmetics in this type is valid, then make sure
5447 that it wraps around. */
5452 {
5455 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5456 for the type in question, as we rely on this here. */
5466 else
5468 }
5472 }
5474 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5475 type, TYPE, return an expression to test if EXP is in (or out of, depending
5476 on IN_P) the range. Return 0 if the test couldn't be created. */
5478 tree
5481 {
5484 /* Disable this optimization for function pointer expressions
5485 on targets that require function pointer canonicalization. */
5492 {
5498 }
5520 value);
5523 {
5525 {
5529 }
5531 }
5533 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5535 {
5539 {
5541 {
5544 etype
5546 else
5549 }
5552 }
5553 }
5555 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5556 This requires wrap-around arithmetics for the type of the expression. */
5573 }
5574 \f
5575 /* Return the predecessor of VAL in its type, handling the infinite case. */
5577 static tree
5579 {
5585 else
5588 }
5590 /* Return the successor of VAL in its type, handling the infinite case. */
5592 static tree
5594 {
5600 else
5603 }
5605 /* Given two ranges, see if we can merge them into one. Return 1 if we
5606 can, 0 if we can't. Set the output range into the specified parameters. */
5608 bool
5611 {
5615 tree tem;
5625 /* Make range 0 be the range that starts first, or ends last if they
5626 start at the same value. Swap them if it isn't. */
5629 || (lowequal
5632 {
5636 }
5638 /* If the second range is != high1 where high1 is the type maximum of
5639 the type, try first merging with < high1 range. */
5641 && high1
5648 {
5653 /* Similarly for the second range != low1 where low1 is the type minimum
5654 of the type, try first merging with > low1 range. */
5659 }
5661 /* Now flag two cases, whether the ranges are disjoint or whether the
5662 second range is totally subsumed in the first. Note that the tests
5663 below are simplified by the ones above. */
5669 /* We now have four cases, depending on whether we are including or
5670 excluding the two ranges. */
5672 {
5673 /* If they don't overlap, the result is false. If the second range
5674 is a subset it is the result. Otherwise, the range is from the start
5675 of the second to the end of the first. */
5680 else
5682 }
5685 {
5686 /* If they don't overlap, the result is the first range. If they are
5687 equal, the result is false. If the second range is a subset of the
5688 first, and the ranges begin at the same place, we go from just after
5689 the end of the second range to the end of the first. If the second
5690 range is not a subset of the first, or if it is a subset and both
5691 ranges end at the same place, the range starts at the start of the
5692 first range and ends just before the second range.
5693 Otherwise, we can't describe this as a single range. */
5699 {
5704 {
5705 /* We are in the weird situation where high0 > high1 but
5706 high1 has no successor. Punt. */
5708 }
5709 }
5711 {
5716 {
5717 /* low0 < low1 but low1 has no predecessor. Punt. */
5719 }
5720 }
5721 else
5723 }
5726 {
5727 /* If they don't overlap, the result is the second range. If the second
5728 is a subset of the first, the result is false. Otherwise,
5729 the range starts just after the first range and ends at the
5730 end of the second. */
5735 else
5736 {
5741 {
5742 /* high1 > high0 but high0 has no successor. Punt. */
5744 }
5745 }
5746 }
5748 else
5749 {
5750 /* The case where we are excluding both ranges. Here the complex case
5751 is if they don't overlap. In that case, the only time we have a
5752 range is if they are adjacent. If the second is a subset of the
5753 first, the result is the first. Otherwise, the range to exclude
5754 starts at the beginning of the first range and ends at the end of the
5755 second. */
5757 {
5762 else
5763 {
5764 /* Canonicalize - [min, x] into - [-, x]. */
5767 {
5770 GET_MODE_BITSIZE
5773 /* FALLTHROUGH */
5786 }
5788 /* Canonicalize - [x, max] into - [x, -]. */
5791 {
5794 GET_MODE_BITSIZE
5797 /* FALLTHROUGH */
5813 }
5815 /* The ranges might be also adjacent between the maximum and
5816 minimum values of the given type. For
5817 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5818 return + [x + 1, y - 1]. */
5820 {
5827 }
5828 else
5830 }
5831 }
5834 else
5836 }
5840 }
5841 \f
5843 /* Subroutine of fold, looking inside expressions of the form
5844 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5845 are the three operands of the COND_EXPR. This function is
5846 being used also to optimize A op B ? C : A, by reversing the
5847 comparison first.
5849 Return a folded expression whose code is not a COND_EXPR
5850 anymore, or NULL_TREE if no folding opportunity is found. */
5852 static tree
5856 {
5858 tree tem;
5863 /* If we have A op 0 ? A : -A, consider applying the following
5864 transformations:
5866 A == 0? A : -A same as -A
5867 A != 0? A : -A same as A
5868 A >= 0? A : -A same as abs (A)
5869 A > 0? A : -A same as abs (A)
5870 A <= 0? A : -A same as -abs (A)
5871 A < 0? A : -A same as -abs (A)
5873 None of these transformations work for modes with signed
5874 zeros. If A is +/-0, the first two transformations will
5875 change the sign of the result (from +0 to -0, or vice
5876 versa). The last four will fix the sign of the result,
5877 even though the original expressions could be positive or
5878 negative, depending on the sign of A.
5880 Note that all these transformations are correct if A is
5881 NaN, since the two alternatives (A and -A) are also NaNs. */
5888 /* In the case that A is of the form X-Y, '-A' (arg2) may
5889 have already been folded to Y-X, check for that. */
5897 {
5909 /* Fall through. */
5920 /* FALLTHRU */
5927 {
5928 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5929 is not, invokes UB both in abs and in the negation of it.
5930 So, use ABSU_EXPR instead. */
5935 }
5936 else
5937 {
5940 }
5944 }
5946 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5947 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5948 both transformations are correct when A is NaN: A != 0
5949 is then true, and A == 0 is false. */
5953 {
5958 }
5960 /* Try some transformations of A op B ? A : B.
5962 A == B? A : B same as B
5963 A != B? A : B same as A
5964 A >= B? A : B same as max (A, B)
5965 A > B? A : B same as max (B, A)
5966 A <= B? A : B same as min (A, B)
5967 A < B? A : B same as min (B, A)
5969 As above, these transformations don't work in the presence
5970 of signed zeros. For example, if A and B are zeros of
5971 opposite sign, the first two transformations will change
5972 the sign of the result. In the last four, the original
5973 expressions give different results for (A=+0, B=-0) and
5974 (A=-0, B=+0), but the transformed expressions do not.
5976 The first two transformations are correct if either A or B
5977 is a NaN. In the first transformation, the condition will
5978 be false, and B will indeed be chosen. In the case of the
5979 second transformation, the condition A != B will be true,
5980 and A will be chosen.
5982 The conversions to max() and min() are not correct if B is
5983 a number and A is not. The conditions in the original
5984 expressions will be false, so all four give B. The min()
5985 and max() versions would give a NaN instead. */
5988 /* Avoid these transformations if the COND_EXPR may be used
5989 as an lvalue in the C++ front-end. PR c++/19199. */
5990 && (in_gimple_form
5996 {
6002 {
6011 /* In C++ a ?: expression can be an lvalue, so put the
6012 operand which will be used if they are equal first
6013 so that we can convert this back to the
6014 corresponding COND_EXPR. */
6016 {
6024 }
6031 {
6039 }
6052 }
6053 }
6056 }
6059 \f
6060 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
6061 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
6062 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
6063 false) >= 2)
6064 #endif
6066 /* EXP is some logical combination of boolean tests. See if we can
6067 merge it into some range test. Return the new tree if so. */
6069 static tree
6072 {
6086 /* If op0 is known true or false and this is a short-circuiting
6087 operation we must not merge with op1 since that makes side-effects
6088 unconditional. So special-case this. */
6095 /* If this is an OR operation, invert both sides; we will invert
6096 again at the end. */
6100 /* If both expressions are the same, if we can merge the ranges, and we
6101 can build the range test, return it or it inverted. If one of the
6102 ranges is always true or always false, consider it to be the same
6103 expression as the other. */
6111 {
6115 }
6117 /* On machines where the branch cost is expensive, if this is a
6118 short-circuited branch and the underlying object on both sides
6119 is the same, make a non-short-circuit operation. */
6122 logical_op_non_short_circuit
6129 {
6130 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6131 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6132 which cases we can't do this. */
6140 {
6149 {
6152 WARN_STRICT_OVERFLOW_COMPARISON);
6156 }
6157 }
6158 }
6161 }
6162 \f
6163 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6164 bit value. Arrange things so the extra bits will be set to zero if and
6165 only if C is signed-extended to its full width. If MASK is nonzero,
6166 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6168 static tree
6170 {
6173 tree temp;
6178 /* We work by getting just the sign bit into the low-order bit, then
6179 into the high-order bit, then sign-extend. We then XOR that value
6180 with C. */
6184 /* We must use a signed type in order to get an arithmetic right shift.
6185 However, we must also avoid introducing accidental overflows, so that
6186 a subsequent call to integer_zerop will work. Hence we must
6187 do the type conversion here. At this point, the constant is either
6188 zero or one, and the conversion to a signed type can never overflow.
6189 We could get an overflow if this conversion is done anywhere else. */
6198 /* If necessary, convert the type back to match the type of C. */
6203 }
6204 \f
6205 /* For an expression that has the form
6206 (A && B) || ~B
6207 or
6208 (A || B) && ~B,
6209 we can drop one of the inner expressions and simplify to
6210 A || ~B
6211 or
6212 A && ~B
6213 LOC is the location of the resulting expression. OP is the inner
6214 logical operation; the left-hand side in the examples above, while CMPOP
6215 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6216 removing a condition that guards another, as in
6217 (A != NULL && A->...) || A == NULL
6218 which we must not transform. If RHS_ONLY is true, only eliminate the
6219 right-most operand of the inner logical operation. */
6221 static tree
6224 {
6242 {
6245 {
6248 }
6249 }
6251 {
6254 {
6257 }
6258 }
6273 }
6275 /* Find ways of folding logical expressions of LHS and RHS:
6276 Try to merge two comparisons to the same innermost item.
6277 Look for range tests like "ch >= '0' && ch <= '9'".
6278 Look for combinations of simple terms on machines with expensive branches
6279 and evaluate the RHS unconditionally.
6281 For example, if we have p->a == 2 && p->b == 4 and we can make an
6282 object large enough to span both A and B, we can do this with a comparison
6283 against the object ANDed with the a mask.
6285 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6286 operations to do this with one comparison.
6288 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6289 function and the one above.
6291 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6292 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6294 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6295 two operands.
6297 We return the simplified tree or 0 if no optimization is possible. */
6299 static tree
6302 {
6303 /* If this is the "or" of two comparisons, we can do something if
6304 the comparisons are NE_EXPR. If this is the "and", we can do something
6305 if the comparisons are EQ_EXPR. I.e.,
6306 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6308 WANTED_CODE is this operation code. For single bit fields, we can
6309 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6310 comparison for one-bit fields. */
6331 /* Start by getting the comparison codes. Fail if anything is volatile.
6332 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6333 it were surrounded with a NE_EXPR. */
6342 {
6346 }
6349 {
6353 }
6364 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6367 {
6370 {
6375 }
6378 {
6384 }
6385 }
6390 /* If the RHS can be evaluated unconditionally and its operands are
6391 simple, it wins to evaluate the RHS unconditionally on machines
6392 with expensive branches. In this case, this isn't a comparison
6393 that can be merged. */
6400 {
6401 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6412 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6422 }
6424 /* See if the comparisons can be merged. Then get all the parameters for
6425 each side. */
6450 /* It must be true that the inner operation on the lhs of each
6451 comparison must be the same if we are to be able to do anything.
6452 Then see if we have constants. If not, the same must be true for
6453 the rhs's. */
6462 {
6465 }
6470 else
6473 /* If either comparison code is not correct for our logical operation,
6474 fail. However, we can convert a one-bit comparison against zero into
6475 the opposite comparison against that bit being set in the field. */
6479 {
6481 {
6482 /* Make the left operand unsigned, since we are only interested
6483 in the value of one bit. Otherwise we are doing the wrong
6484 thing below. */
6487 }
6488 else
6490 }
6492 /* This is analogous to the code for l_const above. */
6494 {
6496 {
6499 }
6500 else
6502 }
6504 /* See if we can find a mode that contains both fields being compared on
6505 the left. If we can't, fail. Otherwise, update all constants and masks
6506 to be relative to a field of that size. */
6520 {
6523 }
6533 {
6542 {
6546 }
6547 }
6549 {
6558 {
6562 }
6563 }
6565 /* If the right sides are not constant, do the same for it. Also,
6566 disallow this optimization if a size, signedness or storage order
6567 mismatch occurs between the left and right sides. */
6569 {
6573 /* Make sure the two fields on the right
6574 correspond to the left without being swapped. */
6591 {
6594 }
6605 /* Make a mask that corresponds to both fields being compared.
6606 Do this for both items being compared. If the operands are the
6607 same size and the bits being compared are in the same position
6608 then we can do this by masking both and comparing the masked
6609 results. */
6616 {
6630 }
6632 /* There is still another way we can do something: If both pairs of
6633 fields being compared are adjacent, we may be able to make a wider
6634 field containing them both.
6636 Note that we still must mask the lhs/rhs expressions. Furthermore,
6637 the mask must be shifted to account for the shift done by
6638 make_bit_field_ref. */
6647 {
6648 tree type;
6666 /* Convert to the smaller type before masking out unwanted bits. */
6669 {
6671 {
6675 }
6677 {
6681 }
6682 }
6691 }
6694 }
6696 /* Handle the case of comparisons with constants. If there is something in
6697 common between the masks, those bits of the constants must be the same.
6698 If not, the condition is always false. Test for this to avoid generating
6699 incorrect code below. */
6704 {
6706 {
6709 }
6710 else
6711 {
6714 }
6715 }
6720 /* Construct the expression we will return. First get the component
6721 reference we will make. Unless the mask is all ones the width of
6722 that field, perform the mask operation. Then compare with the
6723 merged constant. */
6734 }
6735 \f
6736 /* T is an integer expression that is being multiplied, divided, or taken a
6737 modulus (CODE says which and what kind of divide or modulus) by a
6738 constant C. See if we can eliminate that operation by folding it with
6739 other operations already in T. WIDE_TYPE, if non-null, is a type that
6740 should be used for the computation if wider than our type.
6742 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6743 (X * 2) + (Y * 4). We must, however, be assured that either the original
6744 expression would not overflow or that overflow is undefined for the type
6745 in the language in question.
6747 If we return a non-null expression, it is an equivalent form of the
6748 original computation, but need not be in the original type.
6750 We set *STRICT_OVERFLOW_P to true if the return values depends on
6751 signed overflow being undefined. Otherwise we do not change
6752 *STRICT_OVERFLOW_P. */
6754 static tree
6757 {
6758 /* To avoid exponential search depth, refuse to allow recursion past
6759 three levels. Beyond that (1) it's highly unlikely that we'll find
6760 something interesting and (2) we've probably processed it before
6761 when we built the inner expression. */
6764 tree ret;
6769 depth++;
6771 depth--;
6774 }
6776 static tree
6779 {
6791 /* Don't deal with constants of zero here; they confuse the code below. */
6801 /* Note that we need not handle conditional operations here since fold
6802 already handles those cases. So just do arithmetic here. */
6804 {
6806 /* For a constant, we can always simplify if we are a multiply
6807 or (for divide and modulus) if it is a multiple of our constant. */
6811 {
6814 /* If the multiplication overflowed, we lost information on it.
6815 See PR68142 and PR69845. */
6819 }
6825 /* If op0 is an expression ... */
6831 /* ... and has wrapping overflow, and its type is smaller
6832 than ctype, then we cannot pass through as widening. */
6836 /* ... or this is a truncation (t is narrower than op0),
6837 then we cannot pass through this narrowing. */
6840 /* ... or signedness changes for division or modulus,
6841 then we cannot pass through this conversion. */
6845 /* ... or has undefined overflow while the converted to
6846 type has not, we cannot do the operation in the inner type
6847 as that would introduce undefined overflow. */
6852 /* Pass the constant down and see if we can make a simplification. If
6853 we can, replace this expression with the inner simplification for
6854 possible later conversion to our or some other type. */
6865 /* If widening the type changes it from signed to unsigned, then we
6866 must avoid building ABS_EXPR itself as unsigned. */
6868 {
6872 {
6875 }
6877 }
6878 /* If the constant is negative, we cannot simplify this. */
6881 /* FALLTHROUGH */
6883 /* For division and modulus, type can't be unsigned, as e.g.
6884 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6885 For signed types, even with wrapping overflow, this is fine. */
6894 /* If widening the type changes the signedness, then we can't perform
6895 this optimization as that changes the result. */
6899 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6905 {
6912 }
6916 /* If the second operand is constant, this is a multiplication
6917 or floor division, by a power of two, so we can treat it that
6918 way unless the multiplier or divisor overflows. Signed
6919 left-shift overflow is implementation-defined rather than
6920 undefined in C90, so do not convert signed left shift into
6921 multiplication. */
6924 /* const_binop may not detect overflow correctly,
6925 so check for it explicitly here. */
6934 ctype,
6936 t1),
6941 /* See if we can eliminate the operation on both sides. If we can, we
6942 can return a new PLUS or MINUS. If we can't, the only remaining
6943 cases where we can do anything are if the second operand is a
6944 constant. */
6951 /* If not multiplication, we can only do this if both operands
6952 are divisible by c. */
6955 {
6960 }
6962 /* If this was a subtraction, negate OP1 and set it to be an addition.
6963 This simplifies the logic below. */
6965 {
6967 /* If OP1 was not easily negatable, the constant may be OP0. */
6969 {
6972 }
6973 }
6978 /* If either OP1 or C are negative, this optimization is not safe for
6979 some of the division and remainder types while for others we need
6980 to change the code. */
6982 {
6990 }
6992 /* If it's a multiply or a division/modulus operation of a multiple
6993 of our constant, do the operation and verify it doesn't overflow. */
6997 {
7000 /* We allow the constant to overflow with wrapping semantics. */
7004 }
7005 else
7008 /* If we have an unsigned type, we cannot widen the operation since it
7009 will change the result if the original computation overflowed. */
7013 /* The last case is if we are a multiply. In that case, we can
7014 apply the distributive law to commute the multiply and addition
7015 if the multiplication of the constants doesn't overflow
7016 and overflow is defined. With undefined overflow
7017 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
7018 But fold_plusminus_mult_expr would factor back any power-of-two
7019 value so do not distribute in the first place in this case. */
7027 op1);
7032 /* We have a special case here if we are doing something like
7033 (C * 8) % 4 since we know that's zero. */
7036 /* If the multiplication can overflow we cannot optimize this. */
7041 {
7044 }
7046 /* ... fall through ... */
7050 /* If we can extract our operation from the LHS, do so and return a
7051 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
7052 do something only if the second operand is a constant. */
7068 /* If these are the same operation types, we can associate them
7069 assuming no overflow. */
7071 {
7086 }
7088 /* If these operations "cancel" each other, we have the main
7089 optimizations of this pass, which occur when either constant is a
7090 multiple of the other, in which case we replace this with either an
7091 operation or CODE or TCODE.
7093 If we have an unsigned type, we cannot do this since it will change
7094 the result if the original computation overflowed. */
7102 {
7105 {
7111 }
7114 {
7120 }
7121 }
7126 }
7129 }
7130 \f
7131 /* Return a node which has the indicated constant VALUE (either 0 or
7132 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7133 and is of the indicated TYPE. */
7135 tree
7137 {
7146 else
7148 }
7151 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7152 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7153 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7154 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7155 COND is the first argument to CODE; otherwise (as in the example
7156 given here), it is the second argument. TYPE is the type of the
7157 original expression. Return NULL_TREE if no simplification is
7158 possible. */
7160 static tree
7165 {
7173 /* Do not move possibly trapping operations into the conditional as this
7174 pessimizes code and causes gimplification issues when applied late. */
7182 {
7186 /* If this operand throws an expression, then it does not make
7187 sense to try to perform a logical or arithmetic operation
7188 involving it. */
7193 }
7196 {
7201 }
7202 else
7203 /* Detect the case of mixing vector and scalar types - bail out. */
7209 /* This transformation is only worthwhile if we don't have to wrap ARG
7210 in a SAVE_EXPR and the operation can be simplified without recursing
7211 on at least one of the branches once its pushed inside the COND_EXPR. */
7220 {
7224 else
7226 }
7228 {
7232 else
7234 }
7236 /* Check that we have simplified at least one of the branches. */
7241 }
7243 \f
7244 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7246 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7247 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7248 if ARG - ZERO_ARG is the same as X.
7250 If ARG is NULL, check for any value of type TYPE.
7252 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7253 and finite. The problematic cases are when X is zero, and its mode
7254 has signed zeros. In the case of rounding towards -infinity,
7255 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7256 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7258 bool
7261 {
7265 /* Don't allow the fold with -fsignaling-nans. */
7269 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7273 /* There is no case that is safe for all rounding modes. */
7277 /* In a vector or complex, we would need to check the sign of all zeros. */
7283 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7287 /* The mode has signed zeros, and we have to honor their sign.
7288 In this situation, there are only two cases we can return true for.
7289 (i) X - 0 is the same as X with default rounding.
7290 (ii) X + 0 is X when X can't possibly be -0.0. */
7292 }
7294 /* Subroutine of match.pd that optimizes comparisons of a division by
7295 a nonzero integer constant against an integer constant, i.e.
7296 X/C1 op C2.
7298 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7299 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7301 enum tree_code
7304 {
7309 /* We have to do this the hard way to detect unsigned overflow.
7310 prod = int_const_binop (MULT_EXPR, c1, c2); */
7316 {
7320 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7323 }
7325 {
7328 {
7347 }
7348 }
7349 else
7350 {
7351 /* A negative divisor reverses the relational operators. */
7356 {
7375 }
7376 }
7389 }
7392 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7393 equality/inequality test, then return a simplified form of the test
7394 using a sign testing. Otherwise return NULL. TYPE is the desired
7395 result type. */
7397 static tree
7400 tree result_type)
7401 {
7402 /* If this is testing a single bit, we can optimize the test. */
7406 {
7407 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7408 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7412 /* This is only a win if casting to a signed type is cheap,
7413 i.e. when arg00's type is not a partial mode. */
7415 {
7418 result_type,
7421 }
7422 }
7425 }
7427 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7428 equality/inequality test, then return a simplified form of
7429 the test using shifts and logical operations. Otherwise return
7430 NULL. TYPE is the desired result type. */
7432 tree
7435 {
7436 /* If this is testing a single bit, we can optimize the test. */
7440 {
7449 /* First, see if we can fold the single bit test into a sign-bit
7450 test. */
7452 result_type);
7456 /* Otherwise we have (A & C) != 0 where C is a single bit,
7457 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7458 Similarly for (A & C) == 0. */
7460 /* If INNER is a right shift of a constant and it plus BITNUM does
7461 not overflow, adjust BITNUM and INNER. */
7467 {
7470 }
7472 /* If we are going to be able to omit the AND below, we must do our
7473 operations as unsigned. If we must use the AND, we have a choice.
7474 Normally unsigned is faster, but for some machines signed is. */
7492 /* Put the AND last so it can combine with more things. */
7495 /* Make sure to return the proper type. */
7499 }
7501 }
7503 /* Test whether it is preferable to swap two operands, ARG0 and
7504 ARG1, for example because ARG0 is an integer constant and ARG1
7505 isn't. */
7507 bool
7509 {
7523 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7524 for commutative and comparison operators. Ensuring a canonical
7525 form allows the optimizers to find additional redundancies without
7526 having to explicitly check for both orderings. */
7532 /* Put SSA_NAMEs last. */
7538 /* Put variables last. */
7545 }
7548 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7549 means A >= Y && A != MAX, but in this case we know that
7550 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7552 static tree
7554 {
7561 else
7570 {
7573 }
7575 {
7578 }
7579 else
7586 {
7587 /* Convert the pointer types into integer before taking the difference. */
7591 }
7592 else
7599 }
7601 /* Fold a sum or difference of at least one multiplication.
7602 Returns the folded tree or NULL if no simplification could be made. */
7604 static tree
7607 {
7611 /* (A * C) +- (B * C) -> (A+-B) * C.
7612 (A * C) +- A -> A * (C+-1).
7613 We are most concerned about the case where C is a constant,
7614 but other combinations show up during loop reduction. Since
7615 it is not difficult, try all four possibilities. */
7618 {
7621 }
7623 {
7626 }
7627 else
7628 {
7629 /* We cannot generate constant 1 for fract. */
7634 }
7636 {
7639 }
7641 {
7643 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7644 the purpose of this canonicalization. */
7648 {
7651 }
7652 else
7654 }
7655 else
7656 {
7657 /* We cannot generate constant 1 for fract. */
7662 }
7665 /* Prefer factoring a common non-constant. */
7675 /* No identical multiplicands; see if we can find a common
7676 power-of-two factor in non-power-of-two multiplies. This
7677 can help in multi-dimensional array access. */
7679 {
7682 HOST_WIDE_INT tmp;
7684 tree maybe_same;
7686 /* Move min of absolute values to int11. */
7688 {
7693 }
7694 else
7701 /* The remainder should not be a constant, otherwise we
7702 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7703 increased the number of multiplications necessary. */
7705 {
7713 }
7714 }
7721 /* We are neither factoring zero nor minus one. */
7729 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7730 same may be minus one and thus the multiplication may overflow. Perform
7731 the sum operation in an unsigned type. */
7736 /* If the sum evaluated to a constant that is not -INF the multiplication
7737 cannot overflow. */
7744 /* Do not resort to unsigned multiplication because
7745 we lose the no-overflow property of the expression. */
7747 }
7749 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7750 specified by EXPR into the buffer PTR of length LEN bytes.
7751 Return the number of bytes placed in the buffer, or zero
7752 upon failure. */
7754 static int
7756 {
7768 /* Dry run. */
7774 {
7776 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7777 number of bytes. */
7781 {
7788 else
7790 }
7791 else
7795 }
7797 }
7800 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7801 specified by EXPR into the buffer PTR of length LEN bytes.
7802 Return the number of bytes placed in the buffer, or zero
7803 upon failure. */
7805 static int
7807 {
7811 FIXED_VALUE_TYPE value;
7826 }
7829 /* Subroutine of native_encode_expr. Encode the REAL_CST
7830 specified by EXPR into the buffer PTR of length LEN bytes.
7831 Return the number of bytes placed in the buffer, or zero
7832 upon failure. */
7834 static int
7836 {
7842 /* There are always 32 bits in each long, no matter the size of
7843 the hosts long. We handle floating point representations with
7844 up to 192 bits. */
7853 /* Dry run. */
7862 {
7867 {
7874 else
7876 }
7877 else
7878 {
7881 {
7882 /* Reverse bytes within each long, or within the entire float
7883 if it's smaller than a long (for HFmode). */
7886 }
7887 }
7892 }
7894 }
7896 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7897 specified by EXPR into the buffer PTR of length LEN bytes.
7898 Return the number of bytes placed in the buffer, or zero
7899 upon failure. */
7901 static int
7903 {
7905 tree part;
7919 }
7921 /* Like native_encode_vector, but only encode the first COUNT elements.
7922 The other arguments are as for native_encode_vector. */
7924 static int
7927 {
7931 {
7932 /* This is the only case in which elements can be smaller than a byte.
7933 Element 0 is always in the lsb of the containing byte. */
7942 /* Zero the buffer and then set bits later where necessary. */
7951 {
7957 {
7960 }
7961 }
7963 }
7968 {
7970 {
7973 }
7984 }
7986 }
7988 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7989 specified by EXPR into the buffer PTR of length LEN bytes.
7990 Return the number of bytes placed in the buffer, or zero
7991 upon failure. */
7993 static int
7995 {
8000 }
8003 /* Subroutine of native_encode_expr. Encode the STRING_CST
8004 specified by EXPR into the buffer PTR of length LEN bytes.
8005 Return the number of bytes placed in the buffer, or zero
8006 upon failure. */
8008 static int
8010 {
8013 /* Wide-char strings are encoded in target byte-order so native
8014 encoding them is trivial. */
8029 else
8030 {
8033 {
8036 }
8038 }
8040 }
8043 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
8044 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
8045 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
8046 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
8047 sufficient to encode the entire EXPR, or if OFF is out of bounds.
8048 Otherwise, start at byte offset OFF and encode at most LEN bytes.
8049 Return the number of bytes placed in the buffer, or zero upon failure. */
8051 int
8053 {
8054 /* We don't support starting at negative offset and -1 is special. */
8059 {
8080 }
8081 }
8083 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
8084 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
8085 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
8086 machine modes, we can't just use build_nonstandard_integer_type. */
8088 tree
8090 {
8091 machine_mode mode;
8093 {
8100 {
8104 }
8105 }
8111 {
8119 }
8122 }
8124 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8125 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8126 to be non-NULL and OFF zero), then in addition to filling the
8127 bytes pointed by PTR with the value also clear any bits pointed
8128 by MASK that are known to be initialized, keep them as is for
8129 e.g. uninitialized padding bits or uninitialized fields. */
8131 int
8134 {
8137 /* We don't support starting at negative offset and -1 is special. */
8145 {
8149 mask);
8164 {
8165 tree min_index;
8183 {
8188 {
8191 }
8196 else
8200 {
8204 offset_int wpos
8212 offset_int wcount
8219 }
8221 {
8224 offset_int wpos
8232 }
8235 {
8237 {
8248 }
8250 {
8254 }
8255 }
8259 do
8260 {
8265 {
8267 {
8270 fieldsize);
8273 }
8275 ptr
8278 fieldsize,
8281 mask
8285 else
8286 {
8289 }
8290 }
8293 {
8294 /* Partial overlap. */
8300 {
8304 fieldsize);
8305 }
8306 else
8307 {
8311 }
8314 }
8316 }
8318 }
8320 }
8323 {
8333 {
8339 {
8342 }
8345 {
8354 }
8358 else
8362 {
8363 tree fld;
8365 {
8378 }
8380 {
8384 }
8387 {
8388 cnt--;
8394 }
8395 }
8400 {
8413 {
8418 }
8419 }
8420 else
8421 {
8426 }
8431 {
8438 else
8444 }
8453 {
8454 /* FIXME: Handle PDP endian. */
8465 {
8468 }
8469 else
8470 {
8478 else
8479 {
8482 }
8483 }
8493 else
8506 /* If the bitfield does not start at byte boundary, handle
8507 the partial byte at the start. */
8510 {
8512 {
8517 {
8520 else
8522 }
8523 }
8524 else
8525 {
8530 {
8533 else
8537 }
8538 }
8539 }
8540 /* If the bitfield does not end at byte boundary, handle
8541 the partial byte at the end. */
8545 {
8547 {
8554 }
8555 else
8556 {
8563 }
8564 }
8568 {
8573 }
8574 else
8575 {
8576 /* Partial overlap. */
8580 {
8583 }
8587 }
8589 }
8594 {
8597 {
8600 {
8604 }
8607 }
8610 fldsize,
8620 }
8621 else
8622 {
8623 /* Partial overlap. */
8629 {
8633 fieldsize);
8634 }
8635 else
8636 {
8640 }
8643 }
8644 }
8646 }
8648 }
8649 }
8652 /* Subroutine of native_interpret_expr. Interpret the contents of
8653 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8654 If the buffer cannot be interpreted, return NULL_TREE. */
8656 static tree
8658 {
8668 }
8671 /* Subroutine of native_interpret_expr. Interpret the contents of
8672 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8673 If the buffer cannot be interpreted, return NULL_TREE. */
8675 static tree
8677 {
8680 double_int result;
8681 FIXED_VALUE_TYPE fixed_value;
8691 }
8694 /* Subroutine of native_interpret_expr. Interpret the contents of
8695 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8696 If the buffer cannot be interpreted, return NULL_TREE. */
8698 tree
8700 {
8704 /* There are always 32 bits in each long, no matter the size of
8705 the hosts long. We handle floating point representations with
8706 up to 192 bits. */
8707 REAL_VALUE_TYPE r;
8717 {
8718 /* Both OFFSET and BYTE index within a long;
8719 bitpos indexes the whole float. */
8722 {
8729 else
8731 }
8732 else
8733 {
8736 {
8737 /* Reverse bytes within each long, or within the entire float
8738 if it's smaller than a long (for HFmode). */
8741 }
8742 }
8746 }
8750 }
8753 /* Subroutine of native_interpret_expr. Interpret the contents of
8754 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8755 If the buffer cannot be interpreted, return NULL_TREE. */
8757 static tree
8759 {
8774 }
8776 /* Read a vector of type TYPE from the target memory image given by BYTES,
8777 which contains LEN bytes. The vector is known to be encodable using
8778 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8780 Return the vector on success, otherwise return null. */
8782 static tree
8786 {
8790 {
8791 /* This is the only case in which elements can be smaller than a byte.
8792 Element 0 is always in the lsb of the containing byte. */
8799 {
8806 }
8808 }
8816 {
8822 }
8824 }
8826 /* Subroutine of native_interpret_expr. Interpret the contents of
8827 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8828 If the buffer cannot be interpreted, return NULL_TREE. */
8830 static tree
8832 {
8833 tree etype;
8844 }
8847 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8848 the buffer PTR of length LEN as a constant of type TYPE. For
8849 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8850 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8851 return NULL_TREE. */
8853 tree
8855 {
8857 {
8868 {
8869 /* For floating point values in composite modes, punt if this
8870 folding doesn't preserve bit representation. As the mode doesn't
8871 have fixed precision while GCC pretends it does, there could be
8872 valid values that GCC can't really represent accurately.
8873 See PR95450. Even for other modes, e.g. x86 XFmode can have some
8874 bit combinationations which GCC doesn't preserve. */
8884 }
8898 }
8899 }
8901 /* Returns true if we can interpret the contents of a native encoding
8902 as TYPE. */
8904 bool
8906 {
8908 {
8922 }
8923 }
8925 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8926 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8928 tree
8931 {
8934 {
8941 {
8945 }
8950 {
8955 {
8960 }
8964 eltsz);
8968 }
8970 }
8974 {
8982 {
8985 {
8986 poly_int64 bitoffset;
8991 else
9001 }
9002 else
9003 {
9021 HOST_WIDE_INT rpos;
9024 else
9025 {
9028 }
9037 }
9038 }
9041 {
9051 }
9055 {
9060 }
9067 {
9071 /* FIXME: Figure out how to handle PDP endian bitfields. */
9077 else
9081 }
9083 }
9085 }
9087 /* Routines for manipulation of native_encode_expr encoded data if the encoded
9088 or extracted constant positions and/or sizes aren't byte aligned. */
9090 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
9091 bits between adjacent elements. AMNT should be within
9092 [0, BITS_PER_UNIT).
9093 Example, AMNT = 2:
9094 00011111|11100000 << 2 = 01111111|10000000
9095 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
9097 void
9100 {
9109 {
9115 {
9118 }
9119 }
9120 }
9122 /* Like shift_bytes_in_array_left but for big-endian.
9123 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9124 bits between adjacent elements. AMNT should be within
9125 [0, BITS_PER_UNIT).
9126 Example, AMNT = 2:
9127 00011111|11100000 >> 2 = 00000111|11111000
9128 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9130 void
9133 {
9141 {
9148 }
9149 }
9151 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9152 directly on the VECTOR_CST encoding, in a way that works for variable-
9153 length vectors. Return the resulting VECTOR_CST on success or null
9154 on failure. */
9156 static tree
9158 {
9170 /* We can only preserve the semantics of a stepped pattern if the new
9171 vector element is an integer of the same size. */
9176 /* The number of bits needed to encode one element from every pattern
9177 of the original vector. */
9178 unsigned int expr_sequence_bits
9181 /* The number of bits needed to encode one element from every pattern
9182 of the result. */
9183 unsigned int type_sequence_bits
9186 /* Don't try to read more bytes than are available, which can happen
9187 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9188 The general VIEW_CONVERT handling can cope with that case, so there's
9189 no point complicating things here. */
9192 BITS_PER_UNIT);
9197 /* Get enough bytes of EXPR to form the new encoding. */
9205 /* Reencode the bytes as TYPE. */
9209 }
9211 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9212 TYPE at compile-time. If we're unable to perform the conversion
9213 return NULL_TREE. */
9215 static tree
9217 {
9218 /* We support up to 512-bit values (for V8DFmode). */
9222 /* Check that the host and target are sane. */
9235 }
9237 /* Build an expression for the address of T. Folds away INDIRECT_REF
9238 to avoid confusing the gimplify process. */
9240 tree
9242 {
9243 /* The size of the object is not relevant when talking about its address. */
9248 {
9253 }
9256 {
9261 }
9268 {
9273 }
9274 else
9278 }
9280 /* Build an expression for the address of T. */
9282 tree
9284 {
9288 }
9290 /* Fold a unary expression of code CODE and type TYPE with operand
9291 OP0. Return the folded expression if folding is successful.
9292 Otherwise, return NULL_TREE. */
9294 tree
9296 {
9297 tree tem;
9298 tree arg0;
9306 {
9309 {
9310 /* Don't use STRIP_NOPS, because signedness of argument type
9311 matters. */
9313 }
9314 else
9315 {
9316 /* Strip any conversions that don't change the mode. This
9317 is safe for every expression, except for a comparison
9318 expression because its signedness is derived from its
9319 operands.
9321 Note that this is done as an internal manipulation within
9322 the constant folder, in order to find the simplest
9323 representation of the arguments so that their form can be
9324 studied. In any cases, the appropriate type conversions
9325 should be put back in the tree that will get out of the
9326 constant folder. */
9328 }
9331 {
9334 {
9338 }
9339 }
9340 }
9347 {
9354 {
9368 /* If this was a conversion, and all we did was to move into
9369 inside the COND_EXPR, bring it back out. But leave it if
9370 it is a conversion from integer to integer and the
9371 result precision is no wider than a word since such a
9372 conversion is cheap and may be optimized away by combine,
9373 while it couldn't if it were outside the COND_EXPR. Then return
9374 so we don't get into an infinite recursion loop taking the
9375 conversion out and then back in. */
9387 && (INTEGRAL_TYPE_P
9400 }
9401 }
9404 {
9410 CASE_CONVERT:
9414 {
9415 /* If we have (type) (a CMP b) and type is an integral type, return
9416 new expression involving the new type. Canonicalize
9417 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9418 non-integral type.
9419 Do not fold the result as that would not simplify further, also
9420 folding again results in recursions. */
9430 }
9432 /* Handle (T *)&A.B.C for A being of type T and B and C
9433 living at offset zero. This occurs frequently in
9434 C++ upcasting and then accessing the base. */
9438 {
9440 tree offset;
9441 machine_mode mode;
9443 tree base
9447 /* If the reference was to a (constant) zero offset, we can use
9448 the address of the base if it has the same base type
9449 as the result type and the pointer type is unqualified. */
9457 }
9461 /* Detect assigning a bitfield. */
9463 && DECL_BIT_FIELD
9465 {
9466 /* Don't leave an assignment inside a conversion
9467 unless assigning a bitfield. */
9469 /* First do the assignment, then return converted constant. */
9474 }
9476 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9477 constants (if x has signed type, the sign bit cannot be set
9478 in c). This folds extension into the BIT_AND_EXPR.
9479 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9480 very likely don't have maximal range for their precision and this
9481 transformation effectively doesn't preserve non-maximal ranges. */
9485 {
9496 <= HOST_BITS_PER_WIDE_INT
9498 {
9502 cst &= HOST_WIDE_INT_M1U
9506 && !flag_syntax_only
9509 {
9513 }
9514 }
9516 {
9521 }
9522 }
9524 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9525 cast (T1)X will fold away. We assume that this happens when X itself
9526 is a cast. */
9530 {
9534 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9535 when the pointed type needs higher alignment than
9536 the p+ first operand's pointed type. */
9543 /* Similarly, avoid this optimization in GENERIC for -fsanitize=null
9544 when type is a reference type and arg00's type is not,
9545 because arg00 could be validly nullptr and if arg01 doesn't return,
9546 we don't want false positive binding of reference to nullptr. */
9548 && !in_gimple_form
9555 }
9557 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9558 of the same precision, and X is an integer type not narrower than
9559 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9565 {
9571 }
9573 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9574 type of X and Y (integer types only). */
9581 {
9582 /* Be careful not to introduce new overflows. */
9583 tree mult_type;
9586 else
9590 {
9597 }
9598 }
9604 {
9611 }
9622 /* Convert fabs((double)float) into (double)fabsf(float). */
9625 {
9631 targ0));
9632 }
9636 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9655 /* Note that the operand of this must be an int
9656 and its values must be 0 or 1.
9657 ("true" is a fixed value perhaps depending on the language,
9658 but we don't handle values other than 1 correctly yet.) */
9665 /* Fold *&X to X if X is an lvalue. */
9667 {
9674 }
9680 }
9683 /* If the operation was a conversion do _not_ mark a resulting constant
9684 with TREE_OVERFLOW if the original constant was not. These conversions
9685 have implementation defined behavior and retaining the TREE_OVERFLOW
9686 flag here would confuse later passes such as VRP. */
9687 tree
9690 {
9699 }
9701 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9702 operands OP0 and OP1. LOC is the location of the resulting expression.
9703 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9704 Return the folded expression if folding is successful. Otherwise,
9705 return NULL_TREE. */
9706 static tree
9709 {
9710 tree tem;
9712 /* We only do these simplifications if we are optimizing. */
9716 /* Check for things like (A || B) && (A || C). We can convert this
9717 to A || (B && C). Note that either operator can be any of the four
9718 truth and/or operations and the transformation will still be
9719 valid. Also note that we only care about order for the
9720 ANDIF and ORIF operators. If B contains side effects, this
9721 might change the truth-value of A. */
9728 {
9748 /* This case if tricky because we must either have commutative
9749 operators or else A10 must not have side-effects. */
9755 a01);
9756 }
9758 /* See if we can build a range comparison. */
9764 {
9768 }
9772 {
9776 }
9778 /* Check for the possibility of merging component references. If our
9779 lhs is another similar operation, try to merge its rhs with our
9780 rhs. Then try to merge our lhs and rhs. */
9791 logical_op_non_short_circuit
9799 {
9806 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9807 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9808 We don't want to pack more than two leafs to a non-IF AND/OR
9809 expression.
9810 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9811 equal to IF-CODE, then we don't want to add right-hand operand.
9812 If the inner right-hand side of left-hand operand has
9813 side-effects, or isn't simple, then we can't add to it,
9814 as otherwise we might destroy if-sequence. */
9817 /* Needed for sequence points to handle trappings, and
9818 side-effects. */
9820 {
9822 arg1);
9824 tem);
9825 }
9826 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9827 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9830 /* Needed for sequence points to handle trappings, and
9831 side-effects. */
9833 {
9838 }
9839 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9840 into (A OR B).
9841 For sequence point consistancy, we need to check for trapping,
9842 and side-effects. */
9846 }
9849 }
9851 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9852 by changing CODE to reduce the magnitude of constants involved in
9853 ARG0 of the comparison.
9854 Returns a canonicalized comparison tree if a simplification was
9855 possible, otherwise returns NULL_TREE.
9856 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9857 valid if signed overflow is undefined. */
9859 static tree
9863 {
9868 /* Match A +- CST code arg1. We can change this only if overflow
9869 is undefined. */
9872 /* In principle pointers also have undefined overflow behavior,
9873 but that causes problems elsewhere. */
9880 /* Identify the constant in arg0 and its sign. */
9884 /* Overflowed constants and zero will cause problems. */
9889 /* See if we can reduce the magnitude of the constant in
9890 arg0 by changing the comparison code. */
9891 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9895 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9899 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9903 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9907 else
9911 /* Now build the constant reduced in magnitude. But not if that
9912 would produce one outside of its types range. */
9928 }
9930 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9931 overflow further. Try to decrease the magnitude of constants involved
9932 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9933 and put sole constants at the second argument position.
9934 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9936 static tree
9939 {
9940 tree t;
9945 /* Try canonicalization by simplifying arg0. */
9950 {
9954 }
9956 /* Try canonicalization by simplifying arg1 using the swapped
9957 comparison. */
9965 }
9967 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9968 space. This is used to avoid issuing overflow warnings for
9969 expressions like &p->x which cannot wrap. */
9971 static bool
9973 {
9980 poly_wide_int wi_offset;
9986 else
9991 precision);
10006 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
10007 array. */
10016 }
10018 /* Return a positive integer when the symbol DECL is known to have
10019 a nonzero address, zero when it's known not to (e.g., it's a weak
10020 symbol), and a negative integer when the symbol is not yet in the
10021 symbol table and so whether or not its address is zero is unknown.
10022 For function local objects always return positive integer. */
10023 static int
10025 {
10026 /* Normally, don't do anything for variables and functions before symtab is
10027 built; it is quite possible that DECL will be declared weak later.
10028 But if folding_initializer, we need a constant answer now, so create
10029 the symtab entry and prevent later weak declaration. */
10032 = (folding_initializer
10037 /* Function local objects are never NULL. */
10045 }
10047 /* Subroutine of fold_binary. This routine performs all of the
10048 transformations that are common to the equality/inequality
10049 operators (EQ_EXPR and NE_EXPR) and the ordering operators
10050 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
10051 fold_binary should call fold_binary. Fold a comparison with
10052 tree code CODE and type TYPE with operands OP0 and OP1. Return
10053 the folded comparison or NULL_TREE. */
10055 static tree
10058 {
10068 /* For comparisons of pointers we can decompose it to a compile time
10069 comparison of the base objects and the offsets into the object.
10070 This requires at least one operand being an ADDR_EXPR or a
10071 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
10077 {
10080 machine_mode mode;
10084 /* Get base and offset for the access. Strip ADDR_EXPR for
10085 get_inner_reference, but put it back by stripping INDIRECT_REF
10086 off the base object if possible. indirect_baseN will be true
10087 if baseN is not an address but refers to the object itself. */
10090 {
10091 base0
10097 else
10099 }
10101 {
10105 {
10106 base0
10112 else
10114 }
10117 else
10121 {
10128 }
10129 }
10133 {
10134 base1
10140 else
10142 }
10144 {
10148 {
10149 base1
10155 else
10157 }
10160 else
10164 {
10171 }
10172 }
10174 /* If we have equivalent bases we might be able to simplify. */
10178 {
10179 /* We can fold this expression to a constant if the non-constant
10180 offset parts are equal. */
10184 && (equality_code
10185 || (indirect_base0
10188 {
10194 "occur when comparing P +- C1 with "
10196 WARN_STRICT_OVERFLOW_CONDITIONAL);
10199 {
10237 }
10238 }
10239 /* We can simplify the comparison to a comparison of the variable
10240 offset parts if the constant offset parts are equal.
10241 Be careful to use signed sizetype here because otherwise we
10242 mess with array offsets in the wrong way. This is possible
10243 because pointer arithmetic is restricted to retain within an
10244 object and overflow on pointer differences is undefined as of
10245 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10247 && (equality_code
10248 || (indirect_base0
10251 {
10252 /* By converting to signed sizetype we cover middle-end pointer
10253 arithmetic which operates on unsigned pointer types of size
10254 type size and ARRAY_REF offsets which are properly sign or
10255 zero extended from their type in case it is narrower than
10256 sizetype. */
10259 else
10263 else
10270 "occur when comparing P +- C1 with "
10272 WARN_STRICT_OVERFLOW_COMPARISON);
10275 }
10276 }
10277 /* For equal offsets we can simplify to a comparison of the
10278 base addresses. */
10280 && (indirect_base0
10282 && (indirect_base1
10287 {
10293 }
10294 /* Comparison between an ordinary (non-weak) symbol and a null
10295 pointer can be eliminated since such symbols must have a non
10296 null address. In C, relational expressions between pointers
10297 to objects and null pointers are undefined. The results
10298 below follow the C++ rules with the additional property that
10299 every object pointer compares greater than a null pointer.
10300 */
10303 /* Avoid folding references to struct members at offset 0 to
10304 prevent tests like '&ptr->firstmember == 0' from getting
10305 eliminated. When ptr is null, although the -> expression
10306 is strictly speaking invalid, GCC retains it as a matter
10307 of QoI. See PR c/44555. */
10310 && indirect_base0
10311 /* The caller guarantees that when one of the arguments is
10312 constant (i.e., null in this case) it is second. */
10314 {
10316 {
10327 }
10328 }
10329 }
10331 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10332 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10333 the resulting offset is smaller in absolute value than the
10334 original one and has the same sign. */
10343 {
10348 tree cst;
10350 "occur when combining constants around "
10353 /* Put the constant on the side where it doesn't overflow and is
10354 of lower absolute value and of same sign than before. */
10361 {
10364 variable1,
10368 }
10376 {
10382 variable2);
10383 }
10384 }
10390 /* If we are comparing an expression that just has comparisons
10391 of two integer values, arithmetic expressions of those comparisons,
10392 and constants, we can simplify it. There are only three cases
10393 to check: the two values can either be equal, the first can be
10394 greater, or the second can be greater. Fold the expression for
10395 those three values. Since each value must be 0 or 1, we have
10396 eight possibilities, each of which corresponds to the constant 0
10397 or 1 or one of the six possible comparisons.
10399 This handles common cases like (a > b) == 0 but also handles
10400 expressions like ((x > y) - (y > x)) > 0, which supposedly
10401 occur in macroized code. */
10404 {
10408 /* Don't handle degenerate cases here; they should already
10409 have been handled anyway. */
10418 {
10422 /* We can't just pass T to eval_subst in case cval1 or cval2
10423 was the same as ARG1. */
10425 tree high_result
10429 arg1);
10430 tree equal_result
10434 arg1);
10435 tree low_result
10439 arg1);
10441 /* All three of these results should be 0 or 1. Confirm they are.
10442 Then use those values to select the proper code to use. */
10447 {
10448 /* Make a 3-bit mask with the high-order bit being the
10449 value for `>', the next for '=', and the low for '<'. */
10453 {
10455 /* Always false. */
10476 /* Always true. */
10478 }
10481 }
10482 }
10483 }
10486 }
10489 /* Subroutine of fold_binary. Optimize complex multiplications of the
10490 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10491 argument EXPR represents the expression "z" of type TYPE. */
10493 static tree
10495 {
10500 {
10503 }
10505 {
10508 }
10509 else
10510 {
10514 }
10523 }
10526 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10527 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10528 true if successful. */
10530 static bool
10532 {
10537 {
10540 }
10542 {
10548 else
10550 }
10551 else
10557 }
10559 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10560 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10561 NULL_TREE otherwise. */
10563 tree
10565 {
10586 {
10587 HOST_WIDE_INT index;
10593 }
10596 {
10602 }
10603 else
10605 }
10607 /* Try to fold a pointer difference of type TYPE two address expressions of
10608 array references AREF0 and AREF1 using location LOC. Return a
10609 simplified expression for the difference or NULL_TREE. */
10611 static tree
10615 {
10620 /* If the bases are array references as well, recurse. If the bases
10621 are pointer indirections compute the difference of the pointers.
10622 If the bases are equal, we are set. */
10625 && (base_offset
10627 use_pointer_diff)))
10630 && (base_offset
10631 = use_pointer_diff
10641 {
10647 base_offset,
10650 }
10652 }
10654 /* If the real or vector real constant CST of type TYPE has an exact
10655 inverse, return it, else return NULL. */
10657 tree
10659 {
10660 REAL_VALUE_TYPE r;
10661 tree unit_type;
10662 machine_mode mode;
10665 {
10675 {
10679 tree_vector_builder elts;
10684 {
10689 }
10692 }
10696 }
10697 }
10699 /* Mask out the tz least significant bits of X of type TYPE where
10700 tz is the number of trailing zeroes in Y. */
10701 static wide_int
10703 {
10708 }
10710 /* Return true when T is an address and is known to be nonzero.
10711 For floating point we further ensure that T is not denormal.
10712 Similar logic is present in nonzero_address in rtlanal.h.
10714 If the return value is based on the assumption that signed overflow
10715 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10716 change *STRICT_OVERFLOW_P. */
10718 static bool
10720 {
10724 /* Doing something useful for floating point would need more work. */
10730 {
10733 strict_overflow_p);
10739 strict_overflow_p);
10747 }
10750 {
10753 strict_overflow_p);
10761 strict_overflow_p);
10775 strict_overflow_p);
10779 strict_overflow_p);
10782 {
10794 }
10798 }
10800 }
10802 /* Return true when T is an address and is known to be nonzero.
10803 Handle warnings about undefined signed overflow. */
10805 bool
10807 {
10814 "determining that expression is always "
10816 WARN_STRICT_OVERFLOW_MISC);
10818 }
10820 /* Return true if T is known not to be equal to an integer W. */
10822 bool
10824 {
10825 int_range_max vr;
10827 {
10837 else
10843 /* If T has some known zero bits and W has any of those bits set,
10844 then T is known not to be equal to W. */
10852 }
10853 }
10855 /* Fold a binary expression of code CODE and type TYPE with operands
10856 OP0 and OP1. LOC is the location of the resulting expression.
10857 Return the folded expression if folding is successful. Otherwise,
10858 return NULL_TREE. */
10860 tree
10863 {
10878 /* Strip any conversions that don't change the mode. This is
10879 safe for every expression, except for a comparison expression
10880 because its signedness is derived from its operands. So, in
10881 the latter case, only strip conversions that don't change the
10882 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10883 preserved.
10885 Note that this is done as an internal manipulation within the
10886 constant folder, in order to find the simplest representation
10887 of the arguments so that their form can be studied. In any
10888 cases, the appropriate type conversions should be put back in
10889 the tree that will get out of the constant folder. */
10892 {
10895 }
10896 else
10897 {
10900 }
10902 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10903 constant but we can't do arithmetic on them. */
10905 {
10908 {
10912 }
10913 }
10915 /* If this is a commutative operation, and ARG0 is a constant, move it
10916 to ARG1 to reduce the number of tests below. */
10921 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10922 to ARG1 to reduce the number of tests below. */
10931 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10933 First check for cases where an arithmetic operation is applied to a
10934 compound, conditional, or comparison operation. Push the arithmetic
10935 operation inside the compound or conditional to see if any folding
10936 can then be done. Convert comparison to conditional for this purpose.
10937 The also optimizes non-constant cases that used to be done in
10938 expand_expr.
10940 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10941 one of the operands is a comparison and the other is a comparison, a
10942 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10943 code below would make the expression more complex. Change it to a
10944 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10945 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10958 {
10962 boolean_type_node,
10970 }
10974 {
10976 {
10981 tem);
10982 }
10984 {
10989 tem);
10990 }
10995 {
11001 }
11006 {
11012 }
11013 }
11016 {
11018 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
11021 {
11027 }
11029 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
11032 {
11033 tree base;
11034 poly_int64 coffset;
11043 }
11048 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
11054 arg1),
11056 arg0)));
11062 {
11063 /* X + (X / CST) * -CST is X % CST. */
11068 {
11077 cst0));
11078 }
11079 }
11081 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
11082 one. Make sure the type is not saturating and has the signedness of
11083 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11084 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11091 {
11095 }
11098 {
11099 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
11100 (plus (plus (mult) (mult)) (foo)) so that we can
11101 take advantage of the factoring cases below. */
11110 {
11116 else
11129 parg0),
11131 marg)),
11135 return
11141 parg1)));
11142 }
11143 }
11144 else
11145 {
11146 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11147 to __complex__ ( x, y ). This is not the same for SNaNs or
11148 if signed zeros are involved. */
11152 {
11159 {
11163 {
11169 }
11171 {
11177 }
11178 }
11179 }
11181 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11182 We associate floats only if the user has specified
11183 -fassociative-math. */
11187 {
11192 {
11193 tree tree0;
11196 }
11197 }
11198 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11199 We associate floats only if the user has specified
11200 -fassociative-math. */
11204 {
11209 {
11210 tree tree0;
11213 }
11214 }
11215 }
11217 bit_rotate:
11218 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11219 is a rotate of A by C1 bits. */
11220 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11221 is a rotate of A by B bits.
11222 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11223 though in this case CODE must be | and not + or ^, otherwise
11224 it doesn't return A when B is 0. */
11225 {
11227 tree rtype;
11236 /* Only create rotates in complete modes. Other cases are not
11237 expanded properly. */
11240 {
11253 {
11258 }
11263 {
11266 code0 == LSHIFT_EXPR
11269 }
11271 {
11281 {
11285 orig_tree01);
11287 }
11288 }
11292 {
11303 {
11307 orig_tree01);
11309 }
11310 }
11311 }
11312 }
11314 associate:
11315 /* In most languages, can't associate operations on floats through
11316 parentheses. Rather than remember where the parentheses were, we
11317 don't associate floats at all, unless the user has specified
11318 -fassociative-math.
11319 And, we need to make sure type is not saturating. */
11323 {
11329 /* Split both trees into variables, constants, and literals. Then
11330 associate each group together, the constants with literals,
11331 then the result with variables. This increases the chances of
11332 literals being recombined later and of generating relocatable
11333 expressions for the sum of a constant and literal. */
11341 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11345 /* With undefined overflow prefer doing association in a type
11346 which wraps on overflow, if that is one of the operand types. */
11349 {
11357 }
11359 /* With undefined overflow we can only associate constants with one
11360 variable, and constants whose association doesn't overflow. */
11363 {
11365 {
11366 /* ??? If split_tree would handle NEGATE_EXPR we could
11367 simply reject these cases and the allowed cases would
11368 be the var0/minus_var1 ones. */
11374 {
11377 }
11384 {
11387 }
11393 /* The only case we can still associate with two variables
11394 is if they cancel out. */
11398 }
11404 }
11406 /* Only do something if we found more than two objects. Otherwise,
11407 nothing has changed and we risk infinite recursion. */
11415 {
11427 {
11431 }
11433 {
11437 }
11439 /* Preserve the MINUS_EXPR if the negative part of the literal is
11440 greater than the positive part. Otherwise, the multiplicative
11441 folding code (i.e extract_muldiv) may be fooled in case
11442 unsigned constants are subtracted, like in the following
11443 example: ((X*2 + 4) - 8U)/2. */
11445 {
11449 /* But avoid ending up with only negated parts. */
11451 {
11455 }
11456 else
11457 {
11461 }
11462 }
11464 /* Don't introduce overflows through reassociation. */
11469 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11476 /* Eliminate minus_con0. */
11478 {
11485 else
11488 }
11490 /* Eliminate minus_var0. */
11492 {
11496 else
11499 }
11501 return
11504 }
11505 }
11511 /* Fold &a[i] - &a[j] to i-j. */
11516 {
11520 code
11524 }
11526 /* Further transformations are not for pointers. */
11530 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11533 /* If arg0 is e.g. unsigned int and type is int, then this could
11534 introduce UB, because if A is INT_MIN at runtime, the original
11535 expression can be well defined while the latter is not.
11536 See PR83269. */
11545 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11546 __complex__ ( x, -y ). This is not the same for SNaNs or if
11547 signed zeros are involved. */
11551 {
11558 {
11562 {
11564 arg1r ? arg1r
11569 }
11571 {
11575 arg1i ? arg1i
11578 }
11579 }
11580 }
11582 /* A - B -> A + (-B) if B is easily negatable. */
11586 /* Avoid this transformation if B is a positive REAL_CST. */
11594 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11595 one. Make sure the type is not saturating and has the signedness of
11596 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11597 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11604 {
11608 }
11614 {
11615 /* Transform x * -C into -x * C if x is easily negatable. */
11630 {
11633 "occur when simplifying "
11635 WARN_STRICT_OVERFLOW_MISC);
11637 }
11639 /* Optimize z * conj(z) for integer complex numbers. */
11646 }
11647 else
11648 {
11649 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11650 This is not the same for NaNs or if signed zeros are
11651 involved. */
11657 {
11660 return
11666 return
11671 }
11673 /* Optimize z * conj(z) for floating point complex numbers.
11674 Guarded by flag_unsafe_math_optimizations as non-finite
11675 imaginary components don't produce scalar results. */
11684 }
11688 /* Canonicalize (X & C1) | C2. */
11692 {
11697 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11705 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11707 {
11710 }
11712 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11713 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11714 mode which allows further optimizations. */
11719 {
11724 {
11727 }
11728 }
11731 {
11736 }
11737 }
11739 /* See if this can be simplified into a rotate first. If that
11740 is unsuccessful continue in the association code. */
11744 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11752 /* See if this can be simplified into a rotate first. If that
11753 is unsuccessful continue in the association code. */
11757 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11762 {
11763 tree tem2;
11770 }
11771 /* Fold ~X & 1 as (X & 1) == 0. */
11775 {
11776 tree tem2;
11783 }
11784 /* Fold !X & 1 as X == 0. */
11787 {
11791 }
11793 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11794 multiple of 1 << CST. */
11796 {
11803 }
11805 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11806 bits from CST2. */
11810 {
11812 wide_int masked
11819 {
11820 /* Avoid the transform if arg1 is a mask of some
11821 mode which allows further optimizations. */
11828 }
11829 }
11831 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11834 {
11839 return
11841 }
11846 /* Don't touch a floating-point divide by zero unless the mode
11847 of the constant can represent infinity. */
11853 /* (-A) / (-B) -> A / B */
11865 /* Fall through */
11868 /* Simplify A / (B << N) where A and B are positive and B is
11869 a power of 2, to A >> (N + log2(B)). */
11874 {
11877 {
11885 WARN_STRICT_OVERFLOW_MISC);
11891 }
11892 }
11894 /* Fall through */
11902 /* Convert -A / -B to A / B when the type is signed and overflow is
11903 undefined. */
11907 {
11910 "when distributing negation across "
11912 WARN_STRICT_OVERFLOW_MISC);
11917 }
11921 {
11924 "when distributing negation across "
11926 WARN_STRICT_OVERFLOW_MISC);
11931 }
11933 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11934 operation, EXACT_DIV_EXPR.
11936 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11937 At one time others generated faster code, it's not clear if they do
11938 after the last round to changes to the DIV code in expmed.cc. */
11949 {
11953 WARN_STRICT_OVERFLOW_MISC);
11955 }
11967 {
11971 WARN_STRICT_OVERFLOW_MISC);
11973 }
11981 /* Since negative shift count is not well-defined,
11982 don't try to compute it in the compiler. */
11988 /* If we have a rotate of a bit operation with the rotate count and
11989 the second operand of the bit operation both constant,
11990 permute the two operations. */
11996 {
12004 }
12006 /* Two consecutive rotates adding up to the some integer
12007 multiple of the precision of the type can be ignored. */
12023 /* Note that the operands of this must be ints
12024 and their values must be 0 or 1.
12025 ("true" is a fixed value perhaps depending on the language.) */
12026 /* If first arg is constant zero, return it. */
12029 /* FALLTHRU */
12031 /* If either arg is constant true, drop it. */
12035 /* Preserve sequence points. */
12038 /* If second arg is constant zero, result is zero, but first arg
12039 must be evaluated. */
12042 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
12043 case will be handled here. */
12047 /* !X && X is always false. */
12051 /* X && !X is always false. */
12056 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
12057 means A >= Y && A != MAX, but in this case we know that
12058 A < X <= MAX. */
12062 {
12074 }
12083 /* Note that the operands of this must be ints
12084 and their values must be 0 or true.
12085 ("true" is a fixed value perhaps depending on the language.) */
12086 /* If first arg is constant true, return it. */
12089 /* FALLTHRU */
12091 /* If either arg is constant zero, drop it. */
12095 /* Preserve sequence points. */
12098 /* If second arg is constant true, result is true, but we must
12099 evaluate first arg. */
12102 /* Likewise for first arg, but note this only occurs here for
12103 TRUTH_OR_EXPR. */
12107 /* !X || X is always true. */
12111 /* X || !X is always true. */
12116 /* (X && !Y) || (!X && Y) is X ^ Y */
12119 {
12136 }
12145 /* If the second arg is constant zero, drop it. */
12148 /* If the second arg is constant true, this is a logical inversion. */
12150 {
12153 }
12154 /* Identical arguments cancel to zero. */
12158 /* !X ^ X is always true. */
12163 /* X ^ !X is always true. */
12179 /* bool_var != 1 becomes !bool_var. */
12186 /* bool_var == 0 becomes !bool_var. */
12193 /* !exp != 0 becomes !exp */
12198 /* If this is an EQ or NE comparison with zero and ARG0 is
12199 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12200 two operations, but the latter can be done in one less insn
12201 on machines that have only two-operand insns or on which a
12202 constant cannot be the first operand. */
12205 {
12210 {
12218 }
12221 {
12229 }
12230 }
12232 /* If this is a comparison of a field, we may be able to simplify it. */
12235 /* Handle the constant case even without -O
12236 to make sure the warnings are given. */
12238 {
12242 }
12244 /* Optimize comparisons of strlen vs zero to a compare of the
12245 first character of the string vs zero. To wit,
12246 strlen(ptr) == 0 => *ptr == 0
12247 strlen(ptr) != 0 => *ptr != 0
12248 Other cases should reduce to one of these two (or a constant)
12249 due to the return value of strlen being unsigned. */
12251 {
12259 {
12260 tree ptrtype
12262 TYPE_QUAL_CONST));
12268 }
12269 }
12271 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12272 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12276 {
12281 {
12283 {
12286 }
12289 }
12290 }
12292 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12293 (X & C) == 0 when C is a single bit. */
12298 {
12305 arg1));
12306 }
12308 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12309 constant C is a power of two, i.e. a single bit. */
12316 {
12320 }
12322 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12323 when is C is a power of two, i.e. a single bit. */
12330 {
12336 }
12340 {
12343 }
12347 {
12354 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12355 operand_equal_p guarantees no side-effects so we don't need
12356 to use omit_one_operand on Z. */
12360 arg10));
12364 arg11));
12368 arg10));
12372 arg11));
12374 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12377 {
12383 }
12384 }
12386 /* Attempt to simplify equality/inequality comparisons of complex
12387 values. Only lower the comparison if the result is known or
12388 can be simplified to a single scalar comparison. */
12393 {
12398 {
12401 }
12402 else
12403 {
12406 }
12409 {
12412 }
12413 else
12414 {
12417 }
12421 {
12423 {
12428 }
12429 else
12430 {
12435 }
12436 }
12440 {
12442 {
12447 }
12448 else
12449 {
12454 }
12455 }
12456 }
12468 /* Transform comparisons of the form X +- C CMP X. */
12473 {
12478 /* (X - c) > X becomes false. */
12484 /* Likewise (X + c) < X becomes false. */
12490 /* Convert (X - c) <= X to true. */
12497 /* Convert (X + c) >= X to true. */
12503 }
12505 /* If we are comparing an ABS_EXPR with a constant, we can
12506 convert all the cases into explicit comparisons, but they may
12507 well not be faster than doing the ABS and one comparison.
12508 But ABS (X) <= C is a range comparison, which becomes a subtraction
12509 and a comparison, and is probably faster. */
12523 /* Convert ABS_EXPR<x> >= 0 to true. */
12530 {
12533 "when simplifying comparison of "
12535 WARN_STRICT_OVERFLOW_CONDITIONAL);
12538 arg0);
12539 }
12541 /* Convert ABS_EXPR<x> < 0 to false. */
12546 {
12549 "when simplifying comparison of "
12551 WARN_STRICT_OVERFLOW_CONDITIONAL);
12554 arg0);
12555 }
12557 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12558 and similarly for >= into !=. */
12568 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12569 otherwise Y might be >= # of bits in X's type and thus e.g.
12570 (unsigned char) (1 << Y) for Y 15 might be 0.
12571 If the cast is widening, then 1 << Y should have unsigned type,
12572 otherwise if Y is number of bits in the signed shift type minus 1,
12573 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12574 31 might be 0xffffffff80000000. */
12587 {
12593 }
12605 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12606 {
12618 }
12623 /* When pedantic, a compound expression can be neither an lvalue
12624 nor an integer constant expression. */
12627 /* Don't let (0, 0) be null pointer constant. */
12635 }
12637 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12638 ((A & N) + B) & M -> (A + B) & M
12639 Similarly if (N & M) == 0,
12640 ((A | N) + B) & M -> (A + B) & M
12641 and for - instead of + (or unary - instead of +)
12642 and/or ^ instead of |.
12643 If B is constant and (B & M) == 0, fold into A & M.
12645 This function is a helper for match.pd patterns. Return non-NULL
12646 type in which the simplified operation should be performed only
12647 if any optimization is possible.
12649 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12650 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12651 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12652 +/-. */
12653 tree
12658 {
12673 wide_int cst0;
12675 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12676 arg1 (M) is == (1LL << cst) - 1.
12677 Store C into PMOP[0] and D into PMOP[1]. */
12684 {
12691 {
12694 }
12697 /* If C or D is of the form (A & N) where
12698 (N & M) == M, or of the form (A | N) or
12699 (A ^ N) where (N & M) == 0, replace it with A. */
12705 /* If C or D is a N where (N & M) == 0, it can be
12706 omitted (replaced with 0). */
12711 /* Similarly, with C - N where (-N & M) == 0. */
12719 }
12721 /* Only build anything new if we optimized one or both arguments above. */
12727 else
12729 }
12731 /* Used by contains_label_[p1]. */
12733 struct contains_label_data
12734 {
12737 };
12739 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12740 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12741 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12743 static tree
12745 {
12748 {
12759 {
12767 }
12776 }
12777 }
12779 /* Return whether the sub-tree ST contains a label which is accessible from
12780 outside the sub-tree. */
12782 static bool
12784 {
12788 }
12790 /* Fold a ternary expression of code CODE and type TYPE with operands
12791 OP0, OP1, and OP2. Return the folded expression if folding is
12792 successful. Otherwise, return NULL_TREE. */
12794 tree
12797 {
12798 tree tem;
12805 /* If this is a commutative operation, and OP0 is a constant, move it
12806 to OP1 to reduce the number of tests below. */
12815 /* Strip any conversions that don't change the mode. This is safe
12816 for every expression, except for a comparison expression because
12817 its signedness is derived from its operands. So, in the latter
12818 case, only strip conversions that don't change the signedness.
12820 Note that this is done as an internal manipulation within the
12821 constant folder, in order to find the simplest representation of
12822 the arguments so that their form can be studied. In any cases,
12823 the appropriate type conversions should be put back in the tree
12824 that will get out of the constant folder. */
12826 {
12829 }
12832 {
12835 }
12838 {
12841 }
12844 {
12848 {
12854 }
12859 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12860 so all simple results must be passed through pedantic_non_lvalue. */
12862 {
12865 /* Only optimize constant conditions when the selected branch
12866 has the same type as the COND_EXPR. This avoids optimizing
12867 away "c ? x : throw", where the throw has a void type.
12868 Avoid throwing away that operand which contains label. */
12875 }
12877 {
12884 {
12887 {
12895 }
12900 }
12901 }
12903 /* If we have A op B ? A : C, we may be able to convert this to a
12904 simpler expression, depending on the operation and the values
12905 of B and C. Signed zeros prevent all of these transformations,
12906 for reasons given above each one.
12908 Also try swapping the arguments and inverting the conditional. */
12912 {
12919 }
12924 {
12931 arg00,
12932 arg01,
12936 }
12938 /* If the second operand is simpler than the third, swap them
12939 since that produces better jump optimization results. */
12942 {
12944 /* See if this can be inverted. If it can't, possibly because
12945 it was a floating-point inequality comparison, don't do
12946 anything. */
12950 }
12952 /* Convert A ? 1 : 0 to simply A. */
12957 /* If we try to convert OP0 to our type, the
12958 call to fold will try to move the conversion inside
12959 a COND, which will recurse. In that case, the COND_EXPR
12960 is probably the best choice, so leave it alone. */
12964 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12965 over COND_EXPR in cases such as floating point comparisons. */
12974 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12979 {
12980 /* sign_bit_p looks through both zero and sign extensions,
12981 but for this optimization only sign extensions are
12982 usable. */
12985 {
12988 {
12991 }
12993 }
12994 /* sign_bit_p only checks ARG1 bits within A's precision.
12995 If <sign bit of A> has wider type than A, bits outside
12996 of A's precision in <sign bit of A> need to be checked.
12997 If they are all 0, this optimization needs to be done
12998 in unsigned A's type, if they are all 1 in signed A's type,
12999 otherwise this can't be done. */
13005 {
13007 tree tem_type;
13020 {
13023 }
13025 {
13028 }
13029 else
13031 }
13034 return
13040 arg1)));
13041 }
13043 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13044 already handled above. */
13049 {
13059 op1);
13060 }
13062 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13063 is probably obsolete because the first operand should be a
13064 truth value (that's why we have the two cases above), but let's
13065 leave it in until we can confirm this for all front-ends. */
13073 /* operand_equal_p compares just value, not precision, so e.g.
13074 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13075 second operand 32-bit -128, which is not a power of two (or vice
13076 versa. */
13080 /* Disable the transformations below for vectors, since
13081 fold_binary_op_with_conditional_arg may undo them immediately,
13082 yielding an infinite loop. */
13086 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13095 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13100 {
13102 /* Only perform transformation if ARG0 is easily inverted. */
13106 ? BIT_IOR_EXPR
13109 op1);
13110 }
13112 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13117 {
13119 /* Only perform transformation if ARG0 is easily inverted. */
13125 op2);
13126 }
13128 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13140 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13141 of fold_ternary on them. */
13151 {
13153 unsigned HOST_WIDE_INT width
13164 {
13169 {
13171 {
13176 }
13182 }
13183 }
13184 }
13186 /* On constants we can use native encode/interpret to constant
13187 fold (nearly) all BIT_FIELD_REFs. */
13193 {
13196 /* Limit us to a reasonable amount of work. To relax the
13197 other limitations we need bit-shifting of the buffer
13198 and rounding up the size. */
13202 {
13204 unsigned HOST_WIDE_INT len
13209 {
13214 }
13215 }
13216 }
13221 /* Perform constant folding of BIT_INSERT_EXPR. */
13225 {
13226 /* Build a vector of integers from the tree mask. */
13227 vec_perm_builder builder;
13231 /* Create a vec_perm_indices for the integer vector. */
13236 }
13240 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13243 {
13249 wide_int tem2
13253 }
13258 {
13260 unsigned HOST_WIDE_INT elsize
13263 {
13269 {
13275 }
13276 }
13277 }
13283 }
13285 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13286 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13287 constructor element index of the value returned. If the element is
13288 not found NULL_TREE is returned and *CTOR_IDX is updated to
13289 the index of the element after the ACCESS_INDEX position (which
13290 may be outside of the CTOR array). */
13292 tree
13295 {
13301 {
13304 {
13305 /* Static constructors for variably sized objects makes no sense. */
13308 /* ??? When it is obvious that the range is signed, treat it so. */
13313 {
13315 low_bound
13317 SIGNED);
13318 }
13319 else
13320 {
13323 }
13324 }
13325 }
13329 index_sgn);
13341 {
13342 /* Array constructor might explicitly set index, or specify a range,
13343 or leave index NULL meaning that it is next index after previous
13344 one. */
13346 {
13348 max_index = index
13350 else
13351 {
13354 index_sgn);
13355 max_index
13357 index_sgn);
13359 }
13360 }
13362 {
13368 }
13369 else
13372 /* Do we have match? */
13374 {
13376 {
13380 }
13381 }
13383 /* We're past the element we search for. Note during parsing
13384 the elements might not be sorted.
13385 ??? We should use a binary search and a flag on the
13386 CONSTRUCTOR as to whether elements are sorted in declaration
13387 order. */
13389 }
13393 }
13395 /* Perform constant folding and related simplification of EXPR.
13396 The related simplifications include x*1 => x, x*0 => 0, etc.,
13397 and application of the associative law.
13398 NOP_EXPR conversions may be removed freely (as long as we
13399 are careful not to change the type of the overall expression).
13400 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13401 but we can constant-fold them if they have constant operands. */
13403 #ifdef ENABLE_FOLD_CHECKING
13404 # define fold(x) fold_1 (x)
13406 static
13407 #endif
13408 tree
13410 {
13414 tree tem;
13417 /* Return right away if a constant. */
13421 /* CALL_EXPR-like objects with variable numbers of operands are
13422 treated specially. */
13424 {
13426 {
13429 }
13431 }
13434 {
13439 {
13457 }
13458 }
13461 {
13463 {
13470 {
13475 }
13478 }
13480 /* Return a VECTOR_CST if possible. */
13482 {
13488 tree val;
13494 }
13502 }
13504 #ifdef ENABLE_FOLD_CHECKING
13505 #undef fold
13512 /* When --enable-checking=fold, compute a digest of expr before
13513 and after actual fold call to see if fold did not accidentally
13514 change original expr. */
13516 tree
13518 {
13519 tree ret;
13539 }
13541 void
13543 {
13554 }
13556 static void
13558 {
13560 }
13562 static void
13565 {
13571 recursive_label:
13581 {
13582 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13590 }
13598 {
13599 /* Allow these fields to be modified. */
13600 tree tmp;
13611 {
13614 }
13615 }
13617 {
13618 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13619 that and change builtins.cc etc. instead - see PR89543. */
13625 }
13636 {
13639 {
13655 }
13659 {
13672 }
13689 {
13695 }
13698 {
13700 {
13703 }
13705 }
13716 {
13719 }
13729 }
13730 }
13732 /* Helper function for outputting the checksum of a tree T. When
13733 debugging with gdb, you can "define mynext" to be "next" followed
13734 by "call debug_fold_checksum (op0)", then just trace down till the
13735 outputs differ. */
13737 DEBUG_FUNCTION void
13739 {
13754 }
13756 #endif
13758 /* Fold a unary tree expression with code CODE of type TYPE with an
13759 operand OP0. LOC is the location of the resulting expression.
13760 Return a folded expression if successful. Otherwise, return a tree
13761 expression with code CODE of type TYPE with an operand OP0. */
13763 tree
13766 {
13767 tree tem;
13768 #ifdef ENABLE_FOLD_CHECKING
13777 #endif
13783 #ifdef ENABLE_FOLD_CHECKING
13790 #endif
13792 }
13794 /* Fold a binary tree expression with code CODE of type TYPE with
13795 operands OP0 and OP1. LOC is the location of the resulting
13796 expression. Return a folded expression if successful. Otherwise,
13797 return a tree expression with code CODE of type TYPE with operands
13798 OP0 and OP1. */
13800 tree
13803 MEM_STAT_DECL)
13804 {
13805 tree tem;
13806 #ifdef ENABLE_FOLD_CHECKING
13823 #endif
13829 #ifdef ENABLE_FOLD_CHECKING
13844 #endif
13846 }
13848 /* Fold a ternary tree expression with code CODE of type TYPE with
13849 operands OP0, OP1, and OP2. Return a folded expression if
13850 successful. Otherwise, return a tree expression with code CODE of
13851 type TYPE with operands OP0, OP1, and OP2. */
13853 tree
13856 {
13857 tree tem;
13858 #ifdef ENABLE_FOLD_CHECKING
13882 #endif
13889 #ifdef ENABLE_FOLD_CHECKING
13912 #endif
13914 }
13916 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13917 arguments in ARGARRAY, and a null static chain.
13918 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13919 of type TYPE from the given operands as constructed by build_call_array. */
13921 tree
13924 {
13925 tree tem;
13926 #ifdef ENABLE_FOLD_CHECKING
13945 #endif
13951 #ifdef ENABLE_FOLD_CHECKING
13967 #endif
13969 }
13971 /* Perform constant folding and related simplification of initializer
13972 expression EXPR. These behave identically to "fold_buildN" but ignore
13973 potential run-time traps and exceptions that fold must preserve. */
13975 #define START_FOLD_INIT \
13976 int saved_signaling_nans = flag_signaling_nans;\
13977 int saved_trapping_math = flag_trapping_math;\
13978 int saved_rounding_math = flag_rounding_math;\
13979 int saved_trapv = flag_trapv;\
13980 int saved_folding_initializer = folding_initializer;\
13981 flag_signaling_nans = 0;\
13982 flag_trapping_math = 0;\
13983 flag_rounding_math = 0;\
13984 flag_trapv = 0;\
13985 folding_initializer = 1;
13987 #define END_FOLD_INIT \
13988 flag_signaling_nans = saved_signaling_nans;\
13989 flag_trapping_math = saved_trapping_math;\
13990 flag_rounding_math = saved_rounding_math;\
13991 flag_trapv = saved_trapv;\
13992 folding_initializer = saved_folding_initializer;
13994 tree
13996 {
13997 tree result;
13998 START_FOLD_INIT;
14002 END_FOLD_INIT;
14004 }
14006 tree
14009 {
14010 tree result;
14011 START_FOLD_INIT;
14015 END_FOLD_INIT;
14017 }
14019 tree
14022 {
14023 tree result;
14024 START_FOLD_INIT;
14028 END_FOLD_INIT;
14030 }
14032 tree
14035 {
14036 tree result;
14037 START_FOLD_INIT;
14041 END_FOLD_INIT;
14043 }
14045 tree
14048 {
14049 tree result;
14050 START_FOLD_INIT;
14054 END_FOLD_INIT;
14056 }
14058 #undef START_FOLD_INIT
14059 #undef END_FOLD_INIT
14061 /* Determine if first argument is a multiple of second argument. Return 0 if
14062 it is not, or we cannot easily determined it to be.
14064 An example of the sort of thing we care about (at this point; this routine
14065 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14066 fold cases do now) is discovering that
14068 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14070 is a multiple of
14072 SAVE_EXPR (J * 8)
14074 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14076 This code also handles discovering that
14078 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14080 is a multiple of 8 so we don't have to worry about dealing with a
14081 possible remainder.
14083 Note that we *look* inside a SAVE_EXPR only to determine how it was
14084 calculated; it is not safe for fold to do much of anything else with the
14085 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14086 at run time. For example, the latter example above *cannot* be implemented
14087 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14088 evaluation time of the original SAVE_EXPR is not necessarily the same at
14089 the time the new expression is evaluated. The only optimization of this
14090 sort that would be valid is changing
14092 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14094 divided by 8 to
14096 SAVE_EXPR (I) * SAVE_EXPR (J)
14098 (where the same SAVE_EXPR (J) is used in the original and the
14099 transformed version).
14101 NOWRAP specifies whether all outer operations in TYPE should
14102 be considered not wrapping. Any type conversion within TOP acts
14103 as a barrier and we will fall back to NOWRAP being false.
14104 NOWRAP is mostly used to treat expressions in TYPE_SIZE and friends
14105 as not wrapping even though they are generally using unsigned arithmetic. */
14107 int
14109 {
14120 {
14122 /* Bitwise and provides a power of two multiple. If the mask is
14123 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14130 /* If the multiplication can wrap we cannot recurse further unless
14131 the bottom is a power of two which is where wrapping does not
14132 matter. */
14138 {
14144 {
14147 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14149 {
14153 {
14156 }
14157 }
14159 }
14160 }
14165 /* Handle X << CST as X * (1 << CST) and only process the constant. */
14167 {
14170 {
14171 wide_int mul_op
14175 nowrap);
14176 }
14177 }
14182 /* If the addition or subtraction can wrap we cannot recurse further
14183 unless bottom is a power of two which is where wrapping does not
14184 matter. */
14190 /* Handle cases like op0 + 0xfffffffd as op0 - 3 if the expression has
14191 unsigned type. For example, (X / 3) + 0xfffffffd is multiple of 3,
14192 but 0xfffffffd is not. */
14195 && nowrap
14200 /* It is impossible to prove if op0 +- op1 is multiple of bottom
14201 precisely, so be conservative here checking if both op0 and op1
14202 are multiple of bottom. Note we check the second operand first
14203 since it's usually simpler. */
14207 CASE_CONVERT:
14208 /* Can't handle conversions from non-integral or wider integral type. */
14213 /* NOWRAP only extends to operations in the outermost type so
14214 make sure to strip it off here. */
14229 SIGNED);
14235 {
14238 /* Check for special cases to see if top is defined as multiple
14239 of bottom:
14241 top = (X & ~(bottom - 1) ; bottom is power of 2
14243 or
14245 Y = X % bottom
14246 top = X - Y. */
14265 }
14267 /* fall through */
14275 }
14276 }
14278 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14279 This function returns true for integer expressions, and returns
14280 false if uncertain. */
14282 bool
14284 {
14289 {
14312 {
14313 CASE_CFN_FABS:
14314 CASE_CFN_FABS_FN:
14316 CASE_CFN_FMAX:
14317 CASE_CFN_FMAX_FN:
14318 CASE_CFN_FMIN:
14319 CASE_CFN_FMIN_FN:
14324 }
14328 }
14329 }
14331 /* Return true if expression X evaluates to an infinity.
14332 This function returns false for integer expressions. */
14334 bool
14336 {
14340 {
14353 }
14354 }
14356 /* Return true if expression X could evaluate to an infinity.
14357 This function returns false for integer expressions, and returns
14358 true if uncertain. */
14360 bool
14362 {
14366 {
14379 }
14380 }
14382 /* Return true if expression X evaluates to a signaling NaN.
14383 This function returns false for integer expressions. */
14385 bool
14387 {
14391 {
14402 }
14403 }
14405 /* Return true if expression X could evaluate to a signaling NaN.
14406 This function returns false for integer expressions, and returns
14407 true if uncertain. */
14409 bool
14411 {
14415 {
14435 {
14436 CASE_CFN_FABS:
14437 CASE_CFN_FABS_FN:
14439 CASE_CFN_FMAX:
14440 CASE_CFN_FMAX_FN:
14441 CASE_CFN_FMIN:
14442 CASE_CFN_FMIN_FN:
14447 }
14450 }
14451 }
14453 /* Return true if expression X evaluates to a NaN.
14454 This function returns false for integer expressions. */
14456 bool
14458 {
14462 {
14473 }
14474 }
14476 /* Return true if expression X could evaluate to a NaN.
14477 This function returns false for integer expressions, and returns
14478 true if uncertain. */
14480 bool
14482 {
14486 {
14511 {
14512 CASE_CFN_FABS:
14513 CASE_CFN_FABS_FN:
14515 CASE_CFN_FMAX:
14516 CASE_CFN_FMAX_FN:
14517 CASE_CFN_FMIN:
14518 CASE_CFN_FMIN_FN:
14523 }
14526 }
14527 }
14529 /* Return true if expression X could evaluate to -0.0.
14530 This function returns true if uncertain. */
14532 bool
14534 {
14538 {
14553 {
14554 CASE_CFN_FABS:
14555 CASE_CFN_FABS_FN:
14559 }
14562 }
14563 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14564 * but currently those predicates require tree and not const_tree. */
14566 }
14568 #define tree_expr_nonnegative_warnv_p(X, Y) \
14571 #define RECURSE(X) \
14572 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14574 /* Return true if CODE or TYPE is known to be non-negative. */
14576 static bool
14578 {
14581 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14582 have a signed:1 type (where the value is -1 and 0). */
14585 }
14587 /* Return true if (CODE OP0) is known to be non-negative. If the return
14588 value is based on the assumption that signed overflow is undefined,
14589 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14590 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14592 bool
14595 {
14600 {
14602 /* We can't return 1 if flag_wrapv is set because
14603 ABS_EXPR<INT_MIN> = INT_MIN. */
14607 {
14610 }
14618 CASE_CONVERT:
14619 {
14624 {
14628 {
14632 }
14633 }
14635 {
14641 }
14642 }
14647 }
14649 /* We don't know sign of `t', so be conservative and return false. */
14651 }
14653 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14654 value is based on the assumption that signed overflow is undefined,
14655 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14656 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14658 bool
14662 {
14667 {
14673 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14674 both unsigned and at least 2 bits shorter than the result. */
14678 {
14683 {
14687 }
14688 }
14693 {
14694 /* x * x is always non-negative for floating point x
14695 or without overflow. */
14698 {
14703 }
14704 }
14706 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14707 both unsigned and their total bits is shorter than the result. */
14711 {
14730 {
14740 }
14741 }
14748 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14749 things. */
14774 }
14776 /* We don't know sign of `t', so be conservative and return false. */
14778 }
14780 /* Return true if T is known to be non-negative. If the return
14781 value is based on the assumption that signed overflow is undefined,
14782 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14783 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14785 bool
14787 {
14792 {
14806 /* Limit the depth of recursion to avoid quadratic behavior.
14807 This is expected to catch almost all occurrences in practice.
14808 If this code misses important cases that unbounded recursion
14809 would not, passes that need this information could be revised
14810 to provide it through dataflow propagation. */
14818 }
14819 }
14821 /* Return true if T is known to be non-negative. If the return
14822 value is based on the assumption that signed overflow is undefined,
14823 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14824 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14826 bool
14829 {
14831 {
14832 CASE_CFN_ACOS:
14833 CASE_CFN_ACOS_FN:
14834 CASE_CFN_ACOSH:
14835 CASE_CFN_ACOSH_FN:
14836 CASE_CFN_CABS:
14837 CASE_CFN_CABS_FN:
14838 CASE_CFN_COSH:
14839 CASE_CFN_COSH_FN:
14840 CASE_CFN_ERFC:
14841 CASE_CFN_ERFC_FN:
14842 CASE_CFN_EXP:
14843 CASE_CFN_EXP_FN:
14844 CASE_CFN_EXP10:
14845 CASE_CFN_EXP2:
14846 CASE_CFN_EXP2_FN:
14847 CASE_CFN_FABS:
14848 CASE_CFN_FABS_FN:
14849 CASE_CFN_FDIM:
14850 CASE_CFN_FDIM_FN:
14851 CASE_CFN_HYPOT:
14852 CASE_CFN_HYPOT_FN:
14853 CASE_CFN_POW10:
14854 CASE_CFN_FFS:
14855 CASE_CFN_PARITY:
14856 CASE_CFN_POPCOUNT:
14857 CASE_CFN_CLZ:
14858 CASE_CFN_CLRSB:
14863 /* Always true. */
14866 CASE_CFN_SQRT:
14867 CASE_CFN_SQRT_FN:
14868 /* sqrt(-0.0) is -0.0. */
14873 CASE_CFN_ASINH:
14874 CASE_CFN_ASINH_FN:
14875 CASE_CFN_ATAN:
14876 CASE_CFN_ATAN_FN:
14877 CASE_CFN_ATANH:
14878 CASE_CFN_ATANH_FN:
14879 CASE_CFN_CBRT:
14880 CASE_CFN_CBRT_FN:
14881 CASE_CFN_CEIL:
14882 CASE_CFN_CEIL_FN:
14883 CASE_CFN_ERF:
14884 CASE_CFN_ERF_FN:
14885 CASE_CFN_EXPM1:
14886 CASE_CFN_EXPM1_FN:
14887 CASE_CFN_FLOOR:
14888 CASE_CFN_FLOOR_FN:
14889 CASE_CFN_FMOD:
14890 CASE_CFN_FMOD_FN:
14891 CASE_CFN_FREXP:
14892 CASE_CFN_FREXP_FN:
14893 CASE_CFN_ICEIL:
14894 CASE_CFN_IFLOOR:
14895 CASE_CFN_IRINT:
14896 CASE_CFN_IROUND:
14897 CASE_CFN_LCEIL:
14898 CASE_CFN_LDEXP:
14899 CASE_CFN_LFLOOR:
14900 CASE_CFN_LLCEIL:
14901 CASE_CFN_LLFLOOR:
14902 CASE_CFN_LLRINT:
14903 CASE_CFN_LLRINT_FN:
14904 CASE_CFN_LLROUND:
14905 CASE_CFN_LLROUND_FN:
14906 CASE_CFN_LRINT:
14907 CASE_CFN_LRINT_FN:
14908 CASE_CFN_LROUND:
14909 CASE_CFN_LROUND_FN:
14910 CASE_CFN_MODF:
14911 CASE_CFN_MODF_FN:
14912 CASE_CFN_NEARBYINT:
14913 CASE_CFN_NEARBYINT_FN:
14914 CASE_CFN_RINT:
14915 CASE_CFN_RINT_FN:
14916 CASE_CFN_ROUND:
14917 CASE_CFN_ROUND_FN:
14918 CASE_CFN_ROUNDEVEN:
14919 CASE_CFN_ROUNDEVEN_FN:
14920 CASE_CFN_SCALB:
14921 CASE_CFN_SCALBLN:
14922 CASE_CFN_SCALBLN_FN:
14923 CASE_CFN_SCALBN:
14924 CASE_CFN_SCALBN_FN:
14925 CASE_CFN_SIGNBIT:
14926 CASE_CFN_SIGNIFICAND:
14927 CASE_CFN_SINH:
14928 CASE_CFN_SINH_FN:
14929 CASE_CFN_TANH:
14930 CASE_CFN_TANH_FN:
14931 CASE_CFN_TRUNC:
14932 CASE_CFN_TRUNC_FN:
14933 /* True if the 1st argument is nonnegative. */
14936 CASE_CFN_FMAX:
14937 CASE_CFN_FMAX_FN:
14938 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14939 things. In the presence of sNaNs, we're only guaranteed to be
14940 non-negative if both operands are non-negative. In the presence
14941 of qNaNs, we're non-negative if either operand is non-negative
14942 and can't be a qNaN, or if both operands are non-negative. */
14951 CASE_CFN_FMIN:
14952 CASE_CFN_FMIN_FN:
14953 /* True if the 1st AND 2nd arguments are nonnegative. */
14956 CASE_CFN_COPYSIGN:
14957 CASE_CFN_COPYSIGN_FN:
14958 /* True if the 2nd argument is nonnegative. */
14961 CASE_CFN_POWI:
14962 /* True if the 1st argument is nonnegative or the second
14963 argument is an even integer. */
14969 CASE_CFN_POW:
14970 CASE_CFN_POW_FN:
14971 /* True if the 1st argument is nonnegative or the second
14972 argument is an even integer valued real. */
14974 {
14975 REAL_VALUE_TYPE c;
14976 HOST_WIDE_INT n;
14981 {
14982 REAL_VALUE_TYPE cint;
14986 }
14987 }
14992 }
14994 }
14996 /* Return true if T is known to be non-negative. If the return
14997 value is based on the assumption that signed overflow is undefined,
14998 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14999 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15001 static bool
15003 {
15009 {
15011 {
15015 /* If the initializer is non-void, then it's a normal expression
15016 that will be assigned to the slot. */
15020 /* Otherwise, the initializer sets the slot in some way. One common
15021 way is an assignment statement at the end of the initializer. */
15023 {
15031 else
15033 }
15039 }
15042 {
15048 arg0,
15049 arg1,
15051 }
15064 }
15065 }
15067 #undef RECURSE
15068 #undef tree_expr_nonnegative_warnv_p
15070 /* Return true if T is known to be non-negative. If the return
15071 value is based on the assumption that signed overflow is undefined,
15072 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15073 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15075 bool
15077 {
15084 {
15106 }
15109 {
15134 }
15135 }
15137 /* Return true if `t' is known to be non-negative. Handle warnings
15138 about undefined signed overflow. */
15140 bool
15142 {
15149 "determining that expression is always "
15151 WARN_STRICT_OVERFLOW_MISC);
15153 }
15156 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15157 For floating point we further ensure that T is not denormal.
15158 Similar logic is present in nonzero_address in rtlanal.h.
15160 If the return value is based on the assumption that signed overflow
15161 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15162 change *STRICT_OVERFLOW_P. */
15164 bool
15167 {
15169 {
15172 strict_overflow_p);
15175 {
15181 strict_overflow_p));
15182 }
15187 strict_overflow_p);
15191 }
15194 }
15196 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15197 For floating point we further ensure that T is not denormal.
15198 Similar logic is present in nonzero_address in rtlanal.h.
15200 If the return value is based on the assumption that signed overflow
15201 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15202 change *STRICT_OVERFLOW_P. */
15204 bool
15206 tree type,
15207 tree op0,
15209 {
15212 {
15216 {
15217 /* With the presence of negative values it is hard
15218 to say something. */
15225 /* One of operands must be positive and the other non-negative. */
15226 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15227 overflows, on a twos-complement machine the sum of two
15228 nonnegative numbers can never be zero. */
15230 strict_overflow_p)
15232 strict_overflow_p));
15233 }
15238 {
15240 strict_overflow_p)
15242 strict_overflow_p))
15243 {
15246 }
15247 }
15256 {
15259 }
15266 {
15270 /* When both operands are nonzero, then MAX must be too. */
15272 strict_overflow_p))
15275 /* MAX where operand 0 is positive is positive. */
15277 strict_overflow_p);
15278 }
15279 /* MAX where operand 1 is positive is positive. */
15284 {
15288 }
15293 strict_overflow_p)
15295 strict_overflow_p));
15299 }
15302 }
15304 /* Return true when T is an address and is known to be nonzero.
15305 For floating point we further ensure that T is not denormal.
15306 Similar logic is present in nonzero_address in rtlanal.h.
15308 If the return value is based on the assumption that signed overflow
15309 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15310 change *STRICT_OVERFLOW_P. */
15312 bool
15314 {
15317 {
15322 {
15334 /* For objects in symbol table check if we know they are non-zero.
15335 Don't do anything for variables and functions before symtab is built;
15336 it is quite possible that they will be declared weak later. */
15341 /* Constants are never weak. */
15346 }
15354 {
15358 }
15368 }
15370 }
15372 #define integer_valued_real_p(X) \
15375 #define RECURSE(X) \
15376 ((integer_valued_real_p) (X, depth + 1))
15378 /* Return true if the floating point result of (CODE OP0) has an
15379 integer value. We also allow +Inf, -Inf and NaN to be considered
15380 integer values. Return false for signaling NaN.
15382 DEPTH is the current nesting depth of the query. */
15384 bool
15386 {
15388 {
15395 CASE_CONVERT:
15396 {
15403 }
15407 }
15409 }
15411 /* Return true if the floating point result of (CODE OP0 OP1) has an
15412 integer value. We also allow +Inf, -Inf and NaN to be considered
15413 integer values. Return false for signaling NaN.
15415 DEPTH is the current nesting depth of the query. */
15417 bool
15419 {
15421 {
15431 }
15433 }
15435 /* Return true if the floating point result of calling FNDECL with arguments
15436 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15437 considered integer values. Return false for signaling NaN. If FNDECL
15438 takes fewer than 2 arguments, the remaining ARGn are null.
15440 DEPTH is the current nesting depth of the query. */
15442 bool
15444 {
15446 {
15447 CASE_CFN_CEIL:
15448 CASE_CFN_CEIL_FN:
15449 CASE_CFN_FLOOR:
15450 CASE_CFN_FLOOR_FN:
15451 CASE_CFN_NEARBYINT:
15452 CASE_CFN_NEARBYINT_FN:
15453 CASE_CFN_RINT:
15454 CASE_CFN_RINT_FN:
15455 CASE_CFN_ROUND:
15456 CASE_CFN_ROUND_FN:
15457 CASE_CFN_ROUNDEVEN:
15458 CASE_CFN_ROUNDEVEN_FN:
15459 CASE_CFN_TRUNC:
15460 CASE_CFN_TRUNC_FN:
15463 CASE_CFN_FMIN:
15464 CASE_CFN_FMIN_FN:
15465 CASE_CFN_FMAX:
15466 CASE_CFN_FMAX_FN:
15471 }
15473 }
15475 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15476 has an integer value. We also allow +Inf, -Inf and NaN to be
15477 considered integer values. Return false for signaling NaN.
15479 DEPTH is the current nesting depth of the query. */
15481 bool
15483 {
15485 {
15493 /* Limit the depth of recursion to avoid quadratic behavior.
15494 This is expected to catch almost all occurrences in practice.
15495 If this code misses important cases that unbounded recursion
15496 would not, passes that need this information could be revised
15497 to provide it through dataflow propagation. */
15501 depth));
15505 }
15507 }
15509 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15510 has an integer value. We also allow +Inf, -Inf and NaN to be
15511 considered integer values. Return false for signaling NaN.
15513 DEPTH is the current nesting depth of the query. */
15515 static bool
15517 {
15519 {
15530 }
15532 }
15534 #undef RECURSE
15535 #undef integer_valued_real_p
15537 /* Return true if the floating point expression T has an integer value.
15538 We also allow +Inf, -Inf and NaN to be considered integer values.
15539 Return false for signaling NaN.
15541 DEPTH is the current nesting depth of the query. */
15543 bool
15545 {
15553 {
15569 }
15572 {
15578 {
15587 }
15591 }
15592 }
15594 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15595 attempt to fold the expression to a constant without modifying TYPE,
15596 OP0 or OP1.
15598 If the expression could be simplified to a constant, then return
15599 the constant. If the expression would not be simplified to a
15600 constant, then return NULL_TREE. */
15602 tree
15604 {
15607 }
15609 /* Given the components of a unary expression CODE, TYPE and OP0,
15610 attempt to fold the expression to a constant without modifying
15611 TYPE or OP0.
15613 If the expression could be simplified to a constant, then return
15614 the constant. If the expression would not be simplified to a
15615 constant, then return NULL_TREE. */
15617 tree
15619 {
15622 }
15624 /* If EXP represents referencing an element in a constant string
15625 (either via pointer arithmetic or array indexing), return the
15626 tree representing the value accessed, otherwise return NULL. */
15628 tree
15630 {
15634 {
15636 tree index;
15637 tree string;
15642 else
15643 {
15647 /* Optimize the special-case of a zero lower bound.
15649 We convert the low_bound to sizetype to avoid some problems
15650 with constant folding. (E.g. suppose the lower bound is 1,
15651 and its mode is QI. Without the conversion,l (ARRAY
15652 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15653 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15659 }
15661 scalar_int_mode char_mode;
15673 }
15675 }
15677 /* Folds a read from vector element at IDX of vector ARG. */
15679 tree
15681 {
15686 {
15690 {
15697 }
15698 }
15700 }
15702 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15703 an integer constant, real, or fixed-point constant.
15705 TYPE is the type of the result. */
15707 static tree
15709 {
15713 {
15719 {
15720 FIXED_VALUE_TYPE f;
15725 /* Propagate overflow flags. */
15729 }
15733 {
15740 }
15743 }
15746 }
15748 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15749 an integer constant or real constant.
15751 TYPE is the type of the result. */
15753 tree
15755 {
15759 {
15761 {
15762 /* If the value is unsigned or non-negative, then the absolute value
15763 is the same as the ordinary value. */
15767 ;
15769 /* If the value is negative, then the absolute value is
15770 its negation. */
15771 else
15774 /* Force to the destination type, set TREE_OVERFLOW for signed
15775 TYPE only. */
15777 }
15783 else
15789 }
15792 }
15794 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15795 constant. TYPE is the type of the result. */
15797 static tree
15799 {
15803 }
15805 /* Given CODE, a relational operator, the target type, TYPE and two
15806 constant operands OP0 and OP1, return the result of the
15807 relational operation. If the result is not a compile time
15808 constant, then return NULL_TREE. */
15810 static tree
15812 {
15815 /* From here on, the only cases we handle are when the result is
15816 known to be a constant. */
15819 {
15823 /* Handle the cases where either operand is a NaN. */
15825 {
15827 {
15855 }
15858 }
15861 }
15864 {
15868 }
15870 /* Handle equality/inequality of complex constants. */
15872 {
15883 else
15885 }
15888 {
15890 {
15891 /* Have vector comparison with scalar boolean result. */
15899 {
15907 }
15909 }
15910 tree_vector_builder elts;
15915 {
15928 }
15931 }
15933 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15935 To compute GT, swap the arguments and do LT.
15936 To compute GE, do LT and invert the result.
15937 To compute LE, swap the arguments, do LT and invert the result.
15938 To compute NE, do EQ and invert the result.
15940 Therefore, the code below must handle only EQ and LT. */
15943 {
15946 }
15948 /* Note that it is safe to invert for real values here because we
15949 have already handled the one case that it matters. */
15953 {
15956 }
15958 /* Compute a result for LT or EQ if args permit;
15959 Otherwise return T. */
15961 {
15964 else
15966 }
15967 else
15973 }
15975 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15976 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15977 itself. */
15979 tree
15981 {
15982 /* If the expression does not have side effects then we don't have to wrap
15983 it with a cleanup point expression. */
15987 /* If the expression is a return, check to see if the expression inside the
15988 return has no side effects or the right hand side of the modify expression
15989 inside the return. If either don't have side effects set we don't need to
15990 wrap the expression in a cleanup point expression. Note we don't check the
15991 left hand side of the modify because it should always be a return decl. */
15993 {
16000 }
16003 }
16005 /* Given a pointer value OP0 and a type TYPE, return a simplified version
16006 of an indirection through OP0, or NULL_TREE if no simplification is
16007 possible. */
16009 tree
16011 {
16013 tree subtype;
16014 poly_uint64 const_op01;
16023 {
16027 /* *&CONST_DECL -> to the value of the const decl. */
16030 /* *&p => p; make sure to handle *&"str"[cst] here. */
16032 {
16036 else
16038 }
16039 /* *(foo *)&fooarray => fooarray[0] */
16042 && (!in_gimple_form
16044 {
16054 }
16055 /* *(foo *)&complexfoo => __real__ complexfoo */
16059 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
16062 {
16066 index);
16067 }
16068 }
16072 {
16078 {
16079 tree op00type;
16083 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
16086 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
16087 but we want to treat offsets with MSB set as negative.
16088 For the code below negative offsets are invalid and
16089 TYPE_SIZE of the element is something unsigned, so
16090 check whether op01 fits into poly_int64, which implies
16091 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
16092 then just use poly_uint64 because we want to treat the
16093 value as unsigned. */
16095 {
16097 poly_uint64 max_offset
16101 {
16106 }
16107 }
16108 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
16111 {
16113 const_op01))
16115 }
16116 /* ((foo *)&fooarray)[1] => fooarray[1] */
16119 {
16128 {
16133 }
16134 }
16135 }
16136 }
16138 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16141 && (!in_gimple_form
16143 {
16144 tree type_domain;
16154 NULL_TREE);
16155 }
16158 }
16160 /* Builds an expression for an indirection through T, simplifying some
16161 cases. */
16163 tree
16165 {
16173 }
16175 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16177 tree
16179 {
16184 else
16186 }
16188 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16189 whose result is ignored. The type of the returned tree need not be
16190 the same as the original expression. */
16192 tree
16194 {
16200 {
16211 else
16217 {
16233 }
16238 }
16239 }
16241 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16243 tree
16245 {
16251 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16252 have to do anything. Only do this when we are not given a const,
16253 because in that case, this check is more expensive than just
16254 doing it. */
16256 {
16261 }
16263 /* If divisor is a power of two, simplify this to bit manipulation. */
16265 {
16267 {
16281 }
16282 else
16283 {
16284 tree t;
16290 }
16291 }
16292 else
16293 {
16298 }
16301 }
16303 /* Likewise, but round down. */
16305 tree
16307 {
16314 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16315 have to do anything. Only do this when we are not given a const,
16316 because in that case, this check is more expensive than just
16317 doing it. */
16319 {
16324 }
16326 /* If divisor is a power of two, simplify this to bit manipulation. */
16328 {
16329 tree t;
16333 }
16334 else
16335 {
16340 }
16343 }
16345 /* Returns the pointer to the base of the object addressed by EXP and
16346 extracts the information about the offset of the access, storing it
16347 to PBITPOS and POFFSET. */
16349 static tree
16352 {
16353 tree core;
16354 machine_mode mode;
16356 poly_int64 bitsize;
16365 {
16370 }
16372 {
16378 {
16379 poly_offset_int tem
16385 }
16386 }
16387 else
16388 {
16392 }
16395 }
16397 /* Returns true if addresses of E1 and E2 differ by a constant, false
16398 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16400 bool
16402 {
16417 {
16427 }
16429 {
16430 /* If only one of the offsets is non-constant, the difference cannot
16431 be a constant. */
16433 }
16434 else
16439 }
16441 /* Return OFF converted to a pointer offset type suitable as offset for
16442 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16443 tree
16445 {
16449 }
16451 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16452 tree
16454 {
16457 }
16459 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16460 tree
16462 {
16465 }
16467 /* Return a pointer to a NUL-terminated string containing the sequence
16468 of bytes corresponding to the representation of the object referred to
16469 by SRC (or a subsequence of such bytes within it if SRC is a reference
16470 to an initialized constant array plus some constant offset).
16471 Set *STRSIZE the number of bytes in the constant sequence including
16472 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16473 where A is the array that stores the constant sequence that SRC points
16474 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16475 need not point to a string or even an array of characters but may point
16476 to an object of any type. */
16480 {
16481 /* The offset into the array A storing the string, and A's byte size. */
16482 tree offset_node;
16483 tree mem_size;
16490 else
16497 {
16500 else
16502 }
16507 /* ARRAY_SIZE is the byte size of the array the constant sequence
16508 is stored in and equal to sizeof A. INIT_BYTES is the number
16509 of bytes in the constant sequence used to initialize the array,
16510 including any embedded NULs as well as the terminating NUL (for
16511 strings), but not including any trailing zeros/NULs past
16512 the terminating one appended implicitly to a string literal to
16513 zero out the remainder of the array it's stored in. For example,
16514 given:
16515 const char a[7] = "abc\0d";
16516 n = strlen (a + 1);
16517 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16518 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16519 is equal to strlen (A) + 1. */
16524 /* Ideally this would turn into a gcc_checking_assert over time. */
16532 {
16533 /* Compute and store the number of characters from the beginning
16534 of the substring at OFFSET to the end, including the terminating
16535 nul. Offsets past the initial length refer to null strings. */
16538 else
16540 }
16541 else
16542 {
16544 /* Support only properly NUL-terminated single byte strings. */
16549 }
16552 }
16554 /* Return a pointer to a NUL-terminated string corresponding to
16555 the expression STR referencing a constant string, possibly
16556 involving a constant offset. Return null if STR either doesn't
16557 reference a constant string or if it involves a nonconstant
16558 offset. */
16562 {
16564 }
16566 /* Given a tree T, compute which bits in T may be nonzero. */
16568 wide_int
16570 {
16572 {
16590 CASE_CONVERT:
16596 {
16601 }
16605 {
16613 }
16617 {
16625 }
16629 }
16632 }
16634 /* Helper function for address compare simplifications in match.pd.
16635 OP0 and OP1 are ADDR_EXPR operands being compared by CODE.
16636 TYPE is the type of comparison operands.
16637 BASE0, BASE1, OFF0 and OFF1 are set by the function.
16638 GENERIC is true if GENERIC folding and false for GIMPLE folding.
16639 Returns 0 if OP0 is known to be unequal to OP1 regardless of OFF{0,1},
16640 1 if bases are known to be equal and OP0 cmp OP1 depends on OFF0 cmp OFF1,
16641 and 2 if unknown. */
16643 int
16647 {
16657 {
16660 }
16662 {
16665 }
16670 /* Punt in GENERIC on variables with value expressions;
16671 the value expressions might point to fields/elements
16672 of other vars etc. */
16678 {
16682 }
16690 /* Assume different STRING_CSTs with the same content will be
16691 merged. */
16700 {
16703 /* If the offsets are equal we can ignore overflow. */
16706 /* Or if we compare using pointers to decls or strings. */
16711 }
16717 /* At this point we know (or assume) the two pointers point at
16718 different objects. */
16722 /* Punt on non-zero offsets from functions. */
16726 /* Or if the bases are neither decls nor string literals. */
16731 /* For initializers, assume addresses of different functions are
16732 different. */
16738 /* Compute whether one address points to the start of one
16739 object and another one to the end of another one. */
16742 {
16745 else
16747 }
16750 else
16751 {
16755 else
16757 }
16759 {
16762 else
16764 }
16767 else
16768 {
16772 else
16774 }
16776 {
16777 /* If one offset is pointing (or could be) to the beginning of one
16778 object and the other is pointing to one past the last byte of the
16779 other object, punt. */
16784 /* If both offsets are the same, there are some cases we know that are
16785 ok. Either if we know they aren't zero, or if we know both sizes
16786 are no zero. */
16792 }
16794 /* At this point, equal is 2 if either one or both pointers are out of
16795 bounds of their object, or one points to start of its object and the
16796 other points to end of its object. This is unspecified behavior
16797 e.g. in C++. Otherwise equal is 0. */
16801 /* When both pointers point to string literals, even when equal is 0,
16802 due to tail merging of string literals the pointers might be the same. */
16804 {
16811 /* If the bytes in the string literals starting at the pointers
16812 differ, the pointers need to be different. */
16817 {
16822 /* If even the bytes in the string literal before the
16823 pointers are the same, the string literals could be
16824 tail merged. */
16826 }
16828 }
16833 /* If this is a pointer comparison, ignore for now even
16834 valid equalities where one pointer is the offset zero
16835 of one object and the other to one past end of another one. */
16839 /* Assume that string literals can't be adjacent to variables
16840 (automatic or global). */
16844 /* Assume that automatic variables can't be adjacent to global
16845 variables. */
16850 }
16852 /* Return the single non-zero element of a CONSTRUCTOR or NULL_TREE. */
16853 tree
16855 {
16864 {
16868 }
16870 }
16872 #if CHECKING_P
16876 /* Helper functions for writing tests of folding trees. */
16878 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16880 static void
16882 tree constant)
16883 {
16885 }
16887 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16888 wrapping WRAPPED_EXPR. */
16890 static void
16892 tree wrapped_expr)
16893 {
16898 }
16900 /* Verify that various arithmetic binary operations are folded
16901 correctly. */
16903 static void
16905 {
16911 /* Addition. */
16912 /* 1 <-- (0 + 1) */
16914 one);
16916 one);
16918 /* (nonlvalue)x <-- (x + 0) */
16920 x);
16922 /* Subtraction. */
16923 /* 0 <-- (x - x) */
16925 zero);
16927 x);
16929 /* Multiplication. */
16930 /* 0 <-- (x * 0) */
16932 zero);
16934 /* (nonlvalue)x <-- (x * 1) */
16936 x);
16937 }
16939 /* Verify that various binary operations on vectors are folded
16940 correctly. */
16942 static void
16944 {
16951 /* Verify equality tests that return a scalar boolean result. */
16964 }
16966 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16968 static void
16970 {
16973 /* This will be 1 if VEC_MODE isn't a vector mode. */
16980 }
16982 /* Run all of the selftests within this file. */
16984 void
16986 {
16990 }