| blob | 3b397ae2941dc2f714831f2b162eca59f855d64a |
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 {
2675 /* Assume the worst for front-end tree codes. */
2679 }
2682 }
2684 /* Return an expr equal to X but certainly not valid as an lvalue. */
2686 tree
2688 {
2689 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2690 us. */
2697 }
2698 \f
2699 /* Given a tree comparison code, return the code that is the logical inverse.
2700 It is generally not safe to do this for floating-point comparisons, except
2701 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2702 ERROR_MARK in this case. */
2704 enum tree_code
2706 {
2712 {
2743 }
2744 }
2746 /* Similar, but return the comparison that results if the operands are
2747 swapped. This is safe for floating-point. */
2749 enum tree_code
2751 {
2753 {
2779 }
2780 }
2783 /* Convert a comparison tree code from an enum tree_code representation
2784 into a compcode bit-based encoding. This function is the inverse of
2785 compcode_to_comparison. */
2787 static enum comparison_code
2789 {
2791 {
2822 }
2823 }
2825 /* Convert a compcode bit-based encoding of a comparison operator back
2826 to GCC's enum tree_code representation. This function is the
2827 inverse of comparison_to_compcode. */
2829 static enum tree_code
2831 {
2833 {
2864 }
2865 }
2867 /* Return true if COND1 tests the opposite condition of COND2. */
2869 bool
2871 {
2874 && (invert_tree_comparison
2881 }
2883 /* Return a tree for the comparison which is the combination of
2884 doing the AND or OR (depending on CODE) of the two operations LCODE
2885 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2886 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2887 if this makes the transformation invalid. */
2889 tree
2894 {
2901 {
2912 }
2915 {
2916 /* Eliminate unordered comparisons, as well as LTGT and ORD
2917 which are not used unless the mode has NaNs. */
2923 }
2925 {
2926 /* Check that the original operation and the optimized ones will trap
2927 under the same condition. */
2938 /* In a short-circuited boolean expression the LHS might be
2939 such that the RHS, if evaluated, will never trap. For
2940 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2941 if neither x nor y is NaN. (This is a mixed blessing: for
2942 example, the expression above will never trap, hence
2943 optimizing it to x < y would be invalid). */
2948 /* If the comparison was short-circuited, and only the RHS
2949 trapped, we may now generate a spurious trap. */
2954 /* If we changed the conditions that cause a trap, we lose. */
2957 }
2963 else
2964 {
2969 }
2970 }
2971 \f
2972 /* Return nonzero if two operands (typically of the same tree node)
2973 are necessarily equal. FLAGS modifies behavior as follows:
2975 If OEP_ONLY_CONST is set, only return nonzero for constants.
2976 This function tests whether the operands are indistinguishable;
2977 it does not test whether they are equal using C's == operation.
2978 The distinction is important for IEEE floating point, because
2979 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2980 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2982 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2983 even though it may hold multiple values during a function.
2984 This is because a GCC tree node guarantees that nothing else is
2985 executed between the evaluation of its "operands" (which may often
2986 be evaluated in arbitrary order). Hence if the operands themselves
2987 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2988 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2989 unset means assuming isochronic (or instantaneous) tree equivalence.
2990 Unless comparing arbitrary expression trees, such as from different
2991 statements, this flag can usually be left unset.
2993 If OEP_PURE_SAME is set, then pure functions with identical arguments
2994 are considered the same. It is used when the caller has other ways
2995 to ensure that global memory is unchanged in between.
2997 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2998 not values of expressions.
3000 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
3001 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
3003 If OEP_BITWISE is set, then require the values to be bitwise identical
3004 rather than simply numerically equal. Do not take advantage of things
3005 like math-related flags or undefined behavior; only return true for
3006 values that are provably bitwise identical in all circumstances.
3008 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
3009 any operand with side effect. This is unnecesarily conservative in the
3010 case we know that arg0 and arg1 are in disjoint code paths (such as in
3011 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
3012 addresses with TREE_CONSTANT flag set so we know that &var == &var
3013 even if var is volatile. */
3015 bool
3018 {
3026 /* If either is ERROR_MARK, they aren't equal. */
3032 /* Similar, if either does not have a type (like a template id),
3033 they aren't equal. */
3037 /* Bitwise identity makes no sense if the values have different layouts. */
3042 /* We cannot consider pointers to different address space equal. */
3049 /* Check equality of integer constants before bailing out due to
3050 precision differences. */
3052 {
3053 /* Address of INTEGER_CST is not defined; check that we did not forget
3054 to drop the OEP_ADDRESS_OF flags. */
3057 }
3060 {
3061 /* If both types don't have the same signedness, then we can't consider
3062 them equal. We must check this before the STRIP_NOPS calls
3063 because they may change the signedness of the arguments. As pointers
3064 strictly don't have a signedness, require either two pointers or
3065 two non-pointers as well. */
3071 /* If both types don't have the same precision, then it is not safe
3072 to strip NOPs. */
3079 }
3080 #if 0
3081 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3082 sanity check once the issue is solved. */
3083 else
3084 /* Addresses of conversions and SSA_NAMEs (and many other things)
3085 are not defined. Check that we did not forget to drop the
3086 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3089 #endif
3091 /* In case both args are comparisons but with different comparison
3092 code, try to swap the comparison operands of one arg to produce
3093 a match and compare that variant. */
3097 {
3105 }
3108 {
3109 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3111 ;
3113 {
3114 /* If we are interested in comparing addresses ignore
3115 MEM_REF wrappings of the base that can appear just for
3116 TBAA reasons. */
3130 }
3131 else
3133 }
3135 /* When not checking adddresses, this is needed for conversions and for
3136 COMPONENT_REF. Might as well play it safe and always test this. */
3143 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3144 We don't care about side effects in that case because the SAVE_EXPR
3145 takes care of that for us. In all other cases, two expressions are
3146 equal if they have no side effects. If we have two identical
3147 expressions with side effects that should be treated the same due
3148 to the only side effects being identical SAVE_EXPR's, that will
3149 be detected in the recursive calls below.
3150 If we are taking an invariant address of two identical objects
3151 they are necessarily equal as well. */
3158 /* Next handle constant cases, those for which we can return 1 even
3159 if ONLY_CONST is set. */
3162 {
3175 {
3176 /* If we do not distinguish between signed and unsigned zero,
3177 consider them equal. */
3180 }
3184 {
3199 }
3203 flags)
3205 flags));
3216 flags | OEP_ADDRESS_OF
3219 /* In GIMPLE empty constructors are allowed in initializers of
3220 aggregates. */
3224 }
3226 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3227 two instances of undefined behavior will give identical results. */
3231 /* Define macros to test an operand from arg0 and arg1 for equality and a
3232 variant that allows null and views null as being different from any
3233 non-null value. In the latter case, if either is null, the both
3234 must be; otherwise, do the normal comparison. */
3235 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3236 TREE_OPERAND (arg1, N), flags)
3238 #define OP_SAME_WITH_NULL(N) \
3239 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3240 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3243 {
3245 /* Two conversions are equal only if signedness and modes match. */
3247 {
3248 CASE_CONVERT:
3256 }
3266 /* For commutative ops, allow the other order. */
3274 /* If either of the pointer (or reference) expressions we are
3275 dereferencing contain a side effect, these cannot be equal,
3276 but their addresses can be. */
3283 {
3286 {
3290 /* Verify that the access types are compatible. */
3294 }
3299 /* Require the same offset. */
3305 /* Fallthru. */
3313 {
3314 /* Require equal access sizes */
3320 flags)))
3322 /* Verify that access happens in similar types. */
3325 /* Verify that accesses are TBAA compatible. */
3334 /* Verify that alignment is compatible. */
3338 }
3341 /* TARGET_MEM_REF require equal extra operands. */
3352 /* Compare the array index by value if it is constant first as we
3353 may have different types but same value here. */
3359 /* Compare low bound and element size as with OEP_ADDRESS_OF
3360 we have to account for the offset of the ref. */
3365 array_ref_low_bound
3369 array_ref_element_size
3371 flags))));
3374 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3375 may be NULL when we're called to compare MEM_EXPRs. */
3378 {
3381 /* Most of time we only need to compare FIELD_DECLs for equality.
3382 However when determining address look into actual offsets.
3383 These may match for unions and unshared record types. */
3386 {
3389 {
3393 /* Non-FIELD_DECL operands can appear in C++ templates. */
3400 flags))
3402 }
3403 else
3405 }
3406 }
3417 }
3421 {
3423 /* Be sure we pass right ADDRESS_OF flag. */
3440 /* The multiplcation operands are commutative. */
3441 /* FALLTHRU */
3449 /* Otherwise take into account this is a commutative operation. */
3462 /* BIT_INSERT_EXPR has an implict operand as the type precision
3463 of op1. Need to check to make sure they are the same. */
3469 /* FALLTHRU */
3494 /* Virtual table reference. */
3506 {
3511 }
3516 }
3520 {
3524 /* If not both CALL_EXPRs are either internal or normal function
3525 functions, then they are not equal. */
3528 {
3529 /* If the CALL_EXPRs call different internal functions, then they
3530 are not equal. */
3533 }
3534 else
3535 {
3536 /* If the CALL_EXPRs call different functions, then they are not
3537 equal. */
3539 flags))
3541 }
3543 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3544 {
3548 else
3552 }
3554 /* Now see if all the arguments are the same. */
3555 {
3566 /* If we get here and both argument lists are exhausted
3567 then the CALL_EXPRs are equal. */
3569 }
3572 }
3575 /* Consider __builtin_sqrt equal to sqrt. */
3585 {
3586 /* Consider decls with the same name equal. The caller needs
3587 to make sure they refer to the same entity (such as a function
3588 formal parameter). */
3594 }
3599 {
3603 /* In GIMPLE constructors are used only to build vectors from
3604 elements. Individual elements in the constructor must be
3605 indexed in increasing order and form an initial sequence.
3607 We make no effort to compare constructors in generic.
3608 (see sem_variable::equals in ipa-icf which can do so for
3609 constants). */
3614 /* Be sure that vectors constructed have the same representation.
3615 We only tested element precision and modes to match.
3616 Vectors may be BLKmode and thus also check that the number of
3617 parts match. */
3630 {
3635 /* In GIMPLE the indexes can be either NULL or matching i.
3636 Double check this so we won't get false
3637 positives for GENERIC. */
3645 }
3647 }
3650 {
3651 /* Compare the STATEMENT_LISTs. */
3657 {
3658 /* The lists don't have the same number of statements. */
3664 flags & (OEP_LEXICOGRAPHIC
3667 }
3668 }
3673 {
3684 }
3688 }
3690 #undef OP_SAME
3691 #undef OP_SAME_WITH_NULL
3692 }
3694 /* Generate a hash value for an expression. This can be used iteratively
3695 by passing a previous result as the HSTATE argument. */
3697 void
3700 {
3706 {
3709 }
3719 {
3720 /* Alas, constants aren't shared, so we can't rely on pointer
3721 identity. */
3731 {
3735 else
3739 }
3741 {
3745 }
3755 {
3762 }
3764 /* We can just compare by pointer. */
3768 /* The node itself doesn't matter. */
3772 /* Ignore. */
3775 /* A list of expressions, for a CALL_EXPR or as the elements of a
3776 VECTOR_CST. */
3781 {
3787 {
3788 /* In GIMPLE the indexes can be either NULL or matching i. */
3793 }
3795 }
3797 {
3798 tree_stmt_iterator i;
3803 }
3812 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3813 Otherwise nodes that compare equal according to operand_equal_p might
3814 get different hash codes. However, don't do this for machine specific
3815 or front end builtins, since the function code is overloaded in those
3816 cases. */
3819 {
3822 }
3823 /* FALL THROUGH */
3826 {
3830 }
3834 {
3835 /* DECL's have a unique ID */
3837 }
3839 {
3840 /* For comparisons that can be swapped, use the lower
3841 tree code. */
3848 }
3850 {
3851 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3852 operand_equal_p. */
3856 /* Don't hash the type, that can lead to having nodes which
3857 compare equal according to operand_equal_p, but which
3858 have different hash codes. Make sure to include signedness
3859 in the hash computation. */
3862 }
3863 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3871 /* Don't ICE on FE specific trees, or their arguments etc.
3872 during operand_equal_p hash verification. */
3875 else
3876 {
3882 {
3898 {
3905 }
3919 {
3920 /* The multiplication operands are commutative. */
3927 }
3935 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3936 Usually different TARGET_EXPRs just should use
3937 different temporaries in their slots. */
3942 /* Virtual table reference. */
3950 {
3952 /* We compute mangled names only when free_lang_data is run.
3953 In that case we can hash precisely. */
3956 hstate.add_object
3957 (IDENTIFIER_HASH_VALUE
3959 }
3963 }
3965 /* Don't hash the type, that can lead to having nodes which
3966 compare equal according to operand_equal_p, but which
3967 have different hash codes. */
3969 {
3970 /* Make sure to include signness in the hash computation. */
3973 }
3976 {
3977 /* It's a commutative expression. We want to hash it the same
3978 however it appears. We do this by first hashing both operands
3979 and then rehashing based on the order of their independent
3980 hashes. */
3985 }
3986 else
3990 }
3992 }
3993 }
3995 bool
3998 {
3999 /* When checking and unless comparing DECL names, verify that if
4000 the outermost operand_equal_p call returns non-zero then ARG0
4001 and ARG1 have the same hash value. */
4003 {
4005 {
4007 {
4014 }
4016 }
4017 else
4021 }
4024 }
4029 /* Conveinece wrapper around operand_compare class because usually we do
4030 not need to play with the valueizer. */
4032 bool
4034 {
4036 }
4038 namespace inchash
4039 {
4041 /* Generate a hash value for an expression. This can be used iteratively
4042 by passing a previous result as the HSTATE argument.
4044 This function is intended to produce the same hash for expressions which
4045 would compare equal using operand_equal_p. */
4046 void
4048 {
4050 }
4052 }
4053 \f
4054 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
4055 with a different signedness or a narrower precision. */
4057 static bool
4059 {
4067 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4068 and see if the inner values are the same. This removes any
4069 signedness comparison, which doesn't matter here. */
4077 /* Discard a single widening conversion from ARG1 and see if the inner
4078 value is the same as ARG0. */
4087 }
4088 \f
4089 /* See if ARG is an expression that is either a comparison or is performing
4090 arithmetic on comparisons. The comparisons must only be comparing
4091 two different values, which will be stored in *CVAL1 and *CVAL2; if
4092 they are nonzero it means that some operands have already been found.
4093 No variables may be used anywhere else in the expression except in the
4094 comparisons.
4096 If this is true, return 1. Otherwise, return zero. */
4098 static bool
4100 {
4104 /* We can handle some of the tcc_expression cases here. */
4113 {
4132 /* First see if we can handle the first operand, then the second. For
4133 the second operand, we know *CVAL1 can't be zero. It must be that
4134 one side of the comparison is each of the values; test for the
4135 case where this isn't true by failing if the two operands
4136 are the same. */
4145 ;
4149 ;
4150 else
4154 ;
4158 ;
4159 else
4166 }
4167 }
4168 \f
4169 /* ARG is a tree that is known to contain just arithmetic operations and
4170 comparisons. Evaluate the operations in the tree substituting NEW0 for
4171 any occurrence of OLD0 as an operand of a comparison and likewise for
4172 NEW1 and OLD1. */
4174 static tree
4177 {
4182 /* We can handle some of the tcc_expression cases here. */
4190 {
4205 {
4224 }
4225 /* Fall through - ??? */
4228 {
4232 /* We need to check both for exact equality and tree equality. The
4233 former will be true if the operand has a side-effect. In that
4234 case, we know the operand occurred exactly once. */
4247 }
4251 }
4252 }
4253 \f
4254 /* Return a tree for the case when the result of an expression is RESULT
4255 converted to TYPE and OMITTED was previously an operand of the expression
4256 but is now not needed (e.g., we folded OMITTED * 0).
4258 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4259 the conversion of RESULT to TYPE. */
4261 tree
4263 {
4266 /* If the resulting operand is an empty statement, just return the omitted
4267 statement casted to void. */
4277 }
4279 /* Return a tree for the case when the result of an expression is RESULT
4280 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4281 of the expression but are now not needed.
4283 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4284 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4285 evaluated before OMITTED2. Otherwise, if neither has side effects,
4286 just do the conversion of RESULT to TYPE. */
4288 tree
4291 {
4300 }
4302 \f
4303 /* Return a simplified tree node for the truth-negation of ARG. This
4304 never alters ARG itself. We assume that ARG is an operation that
4305 returns a truth value (0 or 1).
4307 FIXME: one would think we would fold the result, but it causes
4308 problems with the dominator optimizer. */
4310 static tree
4312 {
4317 /* If this is a comparison, we can simply invert it, except for
4318 floating-point non-equality comparisons, in which case we just
4319 enclose a TRUTH_NOT_EXPR around what we have. */
4322 {
4325 && flag_trapping_math
4338 }
4341 {
4360 /* Here we can invert either operand. We invert the first operand
4361 unless the second operand is a TRUTH_NOT_EXPR in which case our
4362 result is the XOR of the first operand with the inside of the
4363 negation of the second operand. */
4368 else
4391 {
4398 /* A COND_EXPR may have a throw as one operand, which
4399 then has void type. Just leave void operands
4400 as they are. */
4406 }
4418 CASE_CONVERT:
4422 /* fall through */
4444 }
4445 }
4447 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4448 assume that ARG is an operation that returns a truth value (0 or 1
4449 for scalars, 0 or -1 for vectors). Return the folded expression if
4450 folding is successful. Otherwise, return NULL_TREE. */
4452 static tree
4454 {
4457 ? BIT_NOT_EXPR
4460 }
4462 /* Return a simplified tree node for the truth-negation of ARG. This
4463 never alters ARG itself. We assume that ARG is an operation that
4464 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4466 tree
4468 {
4474 ? BIT_NOT_EXPR
4477 }
4478 \f
4479 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4480 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4481 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4482 is the original memory reference used to preserve the alias set of
4483 the access. */
4485 static tree
4489 {
4492 /* Attempt not to lose the access path if possible. */
4494 {
4496 machine_mode nmode;
4498 tree noffset;
4506 && !reversep
4507 && !nreversep
4509 {
4512 }
4513 }
4522 {
4529 }
4544 }
4546 /* Optimize a bit-field compare.
4548 There are two cases: First is a compare against a constant and the
4549 second is a comparison of two items where the fields are at the same
4550 bit position relative to the start of a chunk (byte, halfword, word)
4551 large enough to contain it. In these cases we can avoid the shift
4552 implicit in bitfield extractions.
4554 For constants, we emit a compare of the shifted constant with the
4555 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4556 compared. For two fields at the same position, we do the ANDs with the
4557 similar mask and compare the result of the ANDs.
4559 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4560 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4561 are the left and right operands of the comparison, respectively.
4563 If the optimization described above can be done, we return the resulting
4564 tree. Otherwise we return zero. */
4566 static tree
4569 {
4573 tree unsigned_type;
4576 scalar_int_mode nmode;
4581 tree mask;
4582 tree offset;
4584 /* Get all the information about the extractions being done. If the bit size
4585 is the same as the size of the underlying object, we aren't doing an
4586 extraction at all and so can do nothing. We also don't want to
4587 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4588 then will no longer be able to replace it. */
4603 else
4604 {
4605 /* If this is not a constant, we can only do something if bit positions,
4606 sizes, signedness and storage order are the same. */
4607 rinner
4620 }
4622 /* Honor the C++ memory model and mimic what RTL expansion does. */
4626 {
4630 }
4632 /* See if we can find a mode to refer to this field. We should be able to,
4633 but fail if we can't. */
4641 /* Set signed and unsigned types of the precision of this mode for the
4642 shifts below. */
4645 /* Compute the bit position and size for the new reference and our offset
4646 within it. If the new reference is the same size as the original, we
4647 won't optimize anything, so return zero. */
4657 /* Make the mask to be used against the extracted field. */
4664 {
4668 /* If not comparing with constant, just rework the comparison
4669 and return. */
4677 }
4679 /* Otherwise, we are handling the constant case. See if the constant is too
4680 big for the field. Warn and return a tree for 0 (false) if so. We do
4681 this not only for its own sake, but to avoid having to test for this
4682 error case below. If we didn't, we might generate wrong code.
4684 For unsigned fields, the constant shifted right by the field length should
4685 be all zero. For signed fields, the high-order bits should agree with
4686 the sign bit. */
4689 {
4691 {
4695 }
4696 }
4697 else
4698 {
4701 {
4705 }
4706 }
4711 /* Single-bit compares should always be against zero. */
4713 {
4716 }
4718 /* Make a new bitfield reference, shift the constant over the
4719 appropriate number of bits and mask it with the computed mask
4720 (in case this was a signed field). If we changed it, make a new one. */
4728 mask);
4733 }
4734 \f
4735 /* Subroutine for fold_truth_andor_1: decode a field reference.
4737 If EXP is a comparison reference, we return the innermost reference.
4739 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4740 set to the starting bit number.
4742 If the innermost field can be completely contained in a mode-sized
4743 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4745 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4746 otherwise it is not changed.
4748 *PUNSIGNEDP is set to the signedness of the field.
4750 *PREVERSEP is set to the storage order of the field.
4752 *PMASK is set to the mask used. This is either contained in a
4753 BIT_AND_EXPR or derived from the width of the field.
4755 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4757 Return 0 if this is not a component reference or is one that we can't
4758 do anything with. */
4760 static tree
4765 {
4770 tree unsigned_type;
4773 /* All the optimizations using this function assume integer fields.
4774 There are problems with FP fields since the type_for_size call
4775 below can fail for, e.g., XFmode. */
4779 /* We are interested in the bare arrangement of bits, so strip everything
4780 that doesn't affect the machine mode. However, record the type of the
4781 outermost expression if it may matter below. */
4788 {
4794 }
4805 /* Reject out-of-bound accesses (PR79731). */
4817 /* If the number of bits in the reference is the same as the bitsize of
4818 the outer type, then the outer type gives the signedness. Otherwise
4819 (in case of a small bitfield) the signedness is unchanged. */
4823 /* Compute the mask to access the bitfield. */
4831 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4839 }
4841 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4842 bit positions and MASK is SIGNED. */
4844 static bool
4846 {
4850 /* If this function returns true when the type of the mask is
4851 UNSIGNED, then there will be errors. In particular see
4852 gcc.c-torture/execute/990326-1.c. There does not appear to be
4853 any documentation paper trail as to why this is so. But the pre
4854 wide-int worked with that restriction and it has been preserved
4855 here. */
4860 }
4862 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4863 represents the sign bit of EXP's type. If EXP represents a sign
4864 or zero extension, also test VAL against the unextended type.
4865 The return value is the (sub)expression whose sign bit is VAL,
4866 or NULL_TREE otherwise. */
4868 tree
4870 {
4872 tree t;
4874 /* Tree EXP must have an integral type. */
4879 /* Tree VAL must be an integer constant. */
4888 /* Handle extension from a narrower type. */
4894 }
4896 /* Subroutine for fold_truth_andor_1 and simple_condition_p: determine if an
4897 operand is simple enough to be evaluated unconditionally. */
4899 static bool
4901 {
4902 /* Strip any conversions that don't change the machine mode. */
4911 /* Don't regard global variables as simple. They may be
4912 allocated in ways unknown to the compiler (shared memory,
4913 #pragma weak, etc). */
4916 /* Weakrefs are not safe to be read, since they can be NULL.
4917 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4918 have DECL_WEAK flag set. */
4920 /* Loading a static variable is unduly expensive, but global
4921 registers aren't expensive. */
4923 }
4925 /* Determine if an operand is simple enough to be evaluated unconditionally.
4926 In addition to simple_operand_p, we assume that comparisons, conversions,
4927 and logic-not operations are simple, if their operands are simple, too. */
4929 bool
4931 {
4950 }
4952 \f
4953 /* The following functions are subroutines to fold_range_test and allow it to
4954 try to change a logical combination of comparisons into a range test.
4956 For example, both
4957 X == 2 || X == 3 || X == 4 || X == 5
4958 and
4959 X >= 2 && X <= 5
4960 are converted to
4961 (unsigned) (X - 2) <= 3
4963 We describe each set of comparisons as being either inside or outside
4964 a range, using a variable named like IN_P, and then describe the
4965 range with a lower and upper bound. If one of the bounds is omitted,
4966 it represents either the highest or lowest value of the type.
4968 In the comments below, we represent a range by two numbers in brackets
4969 preceded by a "+" to designate being inside that range, or a "-" to
4970 designate being outside that range, so the condition can be inverted by
4971 flipping the prefix. An omitted bound is represented by a "-". For
4972 example, "- [-, 10]" means being outside the range starting at the lowest
4973 possible value and ending at 10, in other words, being greater than 10.
4974 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4975 always false.
4977 We set up things so that the missing bounds are handled in a consistent
4978 manner so neither a missing bound nor "true" and "false" need to be
4979 handled using a special case. */
4981 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4982 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4983 and UPPER1_P are nonzero if the respective argument is an upper bound
4984 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4985 must be specified for a comparison. ARG1 will be converted to ARG0's
4986 type if both are specified. */
4988 static tree
4991 {
4992 tree tem;
4996 /* If neither arg represents infinity, do the normal operation.
4997 Else, if not a comparison, return infinity. Else handle the special
4998 comparison rules. Note that most of the cases below won't occur, but
4999 are handled for consistency. */
5002 {
5007 }
5012 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
5013 for neither. In real maths, we cannot assume open ended ranges are
5014 the same. But, this is computer arithmetic, where numbers are finite.
5015 We can therefore make the transformation of any unbounded range with
5016 the value Z, Z being greater than any representable number. This permits
5017 us to treat unbounded ranges as equal. */
5021 {
5042 }
5045 }
5046 \f
5047 /* Helper routine for make_range. Perform one step for it, return
5048 new expression if the loop should continue or NULL_TREE if it should
5049 stop. */
5051 tree
5055 {
5061 {
5063 /* We can only do something if the range is testing for zero. */
5072 /* We can only do something if the range is testing for zero
5073 and if the second operand is an integer constant. Note that
5074 saying something is "in" the range we make is done by
5075 complementing IN_P since it will set in the initial case of
5076 being not equal to zero; "out" is leaving it alone. */
5083 {
5104 }
5106 /* If this is an unsigned comparison, we also know that EXP is
5107 greater than or equal to zero. We base the range tests we make
5108 on that fact, so we record it here so we can parse existing
5109 range tests. We test arg0_type since often the return type
5110 of, e.g. EQ_EXPR, is boolean. */
5112 {
5116 NULL_TREE))
5121 /* If the high bound is missing, but we have a nonzero low
5122 bound, reverse the range so it goes from zero to the low bound
5123 minus 1. */
5125 {
5130 }
5131 }
5139 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5140 low and high are non-NULL, then normalize will DTRT. */
5143 {
5148 }
5150 /* (-x) IN [a,b] -> x in [-b, -a] */
5162 /* ~ X -> -X - 1 */
5171 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5172 move a constant to the other side. */
5177 /* If EXP is signed, any overflow in the computation is undefined,
5178 so we don't worry about it so long as our computations on
5179 the bounds don't overflow. For unsigned, overflow is defined
5180 and this is exactly the right thing. */
5192 normalize:
5193 /* Check for an unsigned range which has wrapped around the maximum
5194 value thus making n_high < n_low, and normalize it. */
5196 {
5202 /* If the range is of the form +/- [ x+1, x ], we won't
5203 be able to normalize it. But then, it represents the
5204 whole range or the empty set, so make it
5205 +/- [ -, - ]. */
5209 else
5211 }
5212 else
5220 CASE_CONVERT:
5238 /* If we're converting arg0 from an unsigned type, to exp,
5239 a signed type, we will be doing the comparison as unsigned.
5240 The tests above have already verified that LOW and HIGH
5241 are both positive.
5243 So we have to ensure that we will handle large unsigned
5244 values the same way that the current signed bounds treat
5245 negative values. */
5248 {
5249 tree high_positive;
5250 tree equiv_type;
5251 /* For fixed-point modes, we need to pass the saturating flag
5252 as the 2nd parameter. */
5254 equiv_type
5257 else
5258 equiv_type
5261 /* A range without an upper bound is, naturally, unbounded.
5262 Since convert would have cropped a very large value, use
5263 the max value for the destination type. */
5264 high_positive
5271 high_positive),
5274 /* If the low bound is specified, "and" the range with the
5275 range for which the original unsigned value will be
5276 positive. */
5278 {
5281 integer_zero_node),
5282 high_positive))
5286 }
5287 else
5288 {
5289 /* Otherwise, "or" the range with the range of the input
5290 that will be interpreted as negative. */
5293 integer_zero_node),
5294 high_positive))
5298 }
5299 }
5301 /* Otherwise, if we are converting arg0 from signed type, to exp,
5302 an unsigned type, we will do the comparison as signed. If
5303 high is non-NULL, we punt above if it doesn't fit in the signed
5304 type, so if we get through here, +[-, high] or +[low, high] are
5305 equivalent to +[-, n_high] or +[n_low, n_high]. Similarly,
5306 +[-, -] or -[-, -] are equivalent too. But if low is specified and
5307 high is not, the +[low, -] range is equivalent to union of
5308 +[n_low, -] and +[-, -1] ranges, so +[low, -] is equivalent to
5309 -[0, n_low-1] and similarly -[low, -] to +[0, n_low-1], except for
5310 low being 0, which should be treated as [-, -]. */
5313 && low
5315 {
5318 else
5319 {
5324 }
5325 }
5334 }
5335 }
5337 /* Given EXP, a logical expression, set the range it is testing into
5338 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5339 actually being tested. *PLOW and *PHIGH will be made of the same
5340 type as the returned expression. If EXP is not a comparison, we
5341 will most likely not be returning a useful value and range. Set
5342 *STRICT_OVERFLOW_P to true if the return value is only valid
5343 because signed overflow is undefined; otherwise, do not change
5344 *STRICT_OVERFLOW_P. */
5346 tree
5349 {
5357 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5358 and see if we can refine the range. Some of the cases below may not
5359 happen, but it doesn't seem worth worrying about this. We "continue"
5360 the outer loop when we've changed something; otherwise we "break"
5361 the switch, which will "break" the while. */
5367 {
5373 {
5381 }
5390 }
5392 /* If EXP is a constant, we can evaluate whether this is true or false. */
5394 {
5401 }
5405 }
5407 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5408 a bitwise check i.e. when
5409 LOW == 0xXX...X00...0
5410 HIGH == 0xXX...X11...1
5411 Return corresponding mask in MASK and stem in VALUE. */
5413 static bool
5416 {
5439 }
5440 \f
5441 /* Helper routine for build_range_check and match.pd. Return the type to
5442 perform the check or NULL if it shouldn't be optimized. */
5444 tree
5446 {
5447 /* First make sure that arithmetics in this type is valid, then make sure
5448 that it wraps around. */
5453 {
5456 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5457 for the type in question, as we rely on this here. */
5467 else
5469 }
5473 }
5475 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5476 type, TYPE, return an expression to test if EXP is in (or out of, depending
5477 on IN_P) the range. Return 0 if the test couldn't be created. */
5479 tree
5482 {
5485 /* Disable this optimization for function pointer expressions
5486 on targets that require function pointer canonicalization. */
5493 {
5499 }
5521 value);
5524 {
5526 {
5530 }
5532 }
5534 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5536 {
5540 {
5542 {
5545 etype
5547 else
5550 }
5553 }
5554 }
5556 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5557 This requires wrap-around arithmetics for the type of the expression. */
5574 }
5575 \f
5576 /* Return the predecessor of VAL in its type, handling the infinite case. */
5578 static tree
5580 {
5586 else
5589 }
5591 /* Return the successor of VAL in its type, handling the infinite case. */
5593 static tree
5595 {
5601 else
5604 }
5606 /* Given two ranges, see if we can merge them into one. Return 1 if we
5607 can, 0 if we can't. Set the output range into the specified parameters. */
5609 bool
5612 {
5616 tree tem;
5626 /* Make range 0 be the range that starts first, or ends last if they
5627 start at the same value. Swap them if it isn't. */
5630 || (lowequal
5633 {
5637 }
5639 /* If the second range is != high1 where high1 is the type maximum of
5640 the type, try first merging with < high1 range. */
5642 && high1
5649 {
5654 /* Similarly for the second range != low1 where low1 is the type minimum
5655 of the type, try first merging with > low1 range. */
5660 }
5662 /* Now flag two cases, whether the ranges are disjoint or whether the
5663 second range is totally subsumed in the first. Note that the tests
5664 below are simplified by the ones above. */
5670 /* We now have four cases, depending on whether we are including or
5671 excluding the two ranges. */
5673 {
5674 /* If they don't overlap, the result is false. If the second range
5675 is a subset it is the result. Otherwise, the range is from the start
5676 of the second to the end of the first. */
5681 else
5683 }
5686 {
5687 /* If they don't overlap, the result is the first range. If they are
5688 equal, the result is false. If the second range is a subset of the
5689 first, and the ranges begin at the same place, we go from just after
5690 the end of the second range to the end of the first. If the second
5691 range is not a subset of the first, or if it is a subset and both
5692 ranges end at the same place, the range starts at the start of the
5693 first range and ends just before the second range.
5694 Otherwise, we can't describe this as a single range. */
5700 {
5705 {
5706 /* We are in the weird situation where high0 > high1 but
5707 high1 has no successor. Punt. */
5709 }
5710 }
5712 {
5717 {
5718 /* low0 < low1 but low1 has no predecessor. Punt. */
5720 }
5721 }
5722 else
5724 }
5727 {
5728 /* If they don't overlap, the result is the second range. If the second
5729 is a subset of the first, the result is false. Otherwise,
5730 the range starts just after the first range and ends at the
5731 end of the second. */
5736 else
5737 {
5742 {
5743 /* high1 > high0 but high0 has no successor. Punt. */
5745 }
5746 }
5747 }
5749 else
5750 {
5751 /* The case where we are excluding both ranges. Here the complex case
5752 is if they don't overlap. In that case, the only time we have a
5753 range is if they are adjacent. If the second is a subset of the
5754 first, the result is the first. Otherwise, the range to exclude
5755 starts at the beginning of the first range and ends at the end of the
5756 second. */
5758 {
5763 else
5764 {
5765 /* Canonicalize - [min, x] into - [-, x]. */
5768 {
5771 GET_MODE_BITSIZE
5774 /* FALLTHROUGH */
5787 }
5789 /* Canonicalize - [x, max] into - [x, -]. */
5792 {
5795 GET_MODE_BITSIZE
5798 /* FALLTHROUGH */
5814 }
5816 /* The ranges might be also adjacent between the maximum and
5817 minimum values of the given type. For
5818 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5819 return + [x + 1, y - 1]. */
5821 {
5828 }
5829 else
5831 }
5832 }
5835 else
5837 }
5841 }
5842 \f
5844 /* Subroutine of fold, looking inside expressions of the form
5845 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5846 are the three operands of the COND_EXPR. This function is
5847 being used also to optimize A op B ? C : A, by reversing the
5848 comparison first.
5850 Return a folded expression whose code is not a COND_EXPR
5851 anymore, or NULL_TREE if no folding opportunity is found. */
5853 static tree
5857 {
5859 tree tem;
5864 /* If we have A op 0 ? A : -A, consider applying the following
5865 transformations:
5867 A == 0? A : -A same as -A
5868 A != 0? A : -A same as 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)
5872 A < 0? A : -A same as -abs (A)
5874 None of these transformations work for modes with signed
5875 zeros. If A is +/-0, the first two transformations will
5876 change the sign of the result (from +0 to -0, or vice
5877 versa). The last four will fix the sign of the result,
5878 even though the original expressions could be positive or
5879 negative, depending on the sign of A.
5881 Note that all these transformations are correct if A is
5882 NaN, since the two alternatives (A and -A) are also NaNs. */
5889 /* In the case that A is of the form X-Y, '-A' (arg2) may
5890 have already been folded to Y-X, check for that. */
5898 {
5910 /* Fall through. */
5921 /* FALLTHRU */
5928 {
5929 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5930 is not, invokes UB both in abs and in the negation of it.
5931 So, use ABSU_EXPR instead. */
5936 }
5937 else
5938 {
5941 }
5945 }
5947 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5948 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5949 both transformations are correct when A is NaN: A != 0
5950 is then true, and A == 0 is false. */
5954 {
5959 }
5961 /* Try some transformations of A op B ? A : B.
5963 A == B? A : B same as B
5964 A != B? A : B same as A
5965 A >= B? A : B same as max (A, B)
5966 A > B? A : B same as max (B, A)
5967 A <= B? A : B same as min (A, B)
5968 A < B? A : B same as min (B, A)
5970 As above, these transformations don't work in the presence
5971 of signed zeros. For example, if A and B are zeros of
5972 opposite sign, the first two transformations will change
5973 the sign of the result. In the last four, the original
5974 expressions give different results for (A=+0, B=-0) and
5975 (A=-0, B=+0), but the transformed expressions do not.
5977 The first two transformations are correct if either A or B
5978 is a NaN. In the first transformation, the condition will
5979 be false, and B will indeed be chosen. In the case of the
5980 second transformation, the condition A != B will be true,
5981 and A will be chosen.
5983 The conversions to max() and min() are not correct if B is
5984 a number and A is not. The conditions in the original
5985 expressions will be false, so all four give B. The min()
5986 and max() versions would give a NaN instead. */
5989 /* Avoid these transformations if the COND_EXPR may be used
5990 as an lvalue in the C++ front-end. PR c++/19199. */
5991 && (in_gimple_form
5997 {
6003 {
6012 /* In C++ a ?: expression can be an lvalue, so put the
6013 operand which will be used if they are equal first
6014 so that we can convert this back to the
6015 corresponding COND_EXPR. */
6017 {
6025 }
6032 {
6040 }
6053 }
6054 }
6057 }
6060 \f
6061 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
6062 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
6063 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
6064 false) >= 2)
6065 #endif
6067 /* EXP is some logical combination of boolean tests. See if we can
6068 merge it into some range test. Return the new tree if so. */
6070 static tree
6073 {
6087 /* If op0 is known true or false and this is a short-circuiting
6088 operation we must not merge with op1 since that makes side-effects
6089 unconditional. So special-case this. */
6096 /* If this is an OR operation, invert both sides; we will invert
6097 again at the end. */
6101 /* If both expressions are the same, if we can merge the ranges, and we
6102 can build the range test, return it or it inverted. If one of the
6103 ranges is always true or always false, consider it to be the same
6104 expression as the other. */
6112 {
6116 }
6118 /* On machines where the branch cost is expensive, if this is a
6119 short-circuited branch and the underlying object on both sides
6120 is the same, make a non-short-circuit operation. */
6123 logical_op_non_short_circuit
6130 {
6131 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6132 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6133 which cases we can't do this. */
6141 {
6150 {
6153 WARN_STRICT_OVERFLOW_COMPARISON);
6157 }
6158 }
6159 }
6162 }
6163 \f
6164 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6165 bit value. Arrange things so the extra bits will be set to zero if and
6166 only if C is signed-extended to its full width. If MASK is nonzero,
6167 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6169 static tree
6171 {
6174 tree temp;
6179 /* We work by getting just the sign bit into the low-order bit, then
6180 into the high-order bit, then sign-extend. We then XOR that value
6181 with C. */
6185 /* We must use a signed type in order to get an arithmetic right shift.
6186 However, we must also avoid introducing accidental overflows, so that
6187 a subsequent call to integer_zerop will work. Hence we must
6188 do the type conversion here. At this point, the constant is either
6189 zero or one, and the conversion to a signed type can never overflow.
6190 We could get an overflow if this conversion is done anywhere else. */
6199 /* If necessary, convert the type back to match the type of C. */
6204 }
6205 \f
6206 /* For an expression that has the form
6207 (A && B) || ~B
6208 or
6209 (A || B) && ~B,
6210 we can drop one of the inner expressions and simplify to
6211 A || ~B
6212 or
6213 A && ~B
6214 LOC is the location of the resulting expression. OP is the inner
6215 logical operation; the left-hand side in the examples above, while CMPOP
6216 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6217 removing a condition that guards another, as in
6218 (A != NULL && A->...) || A == NULL
6219 which we must not transform. If RHS_ONLY is true, only eliminate the
6220 right-most operand of the inner logical operation. */
6222 static tree
6225 {
6243 {
6246 {
6249 }
6250 }
6252 {
6255 {
6258 }
6259 }
6274 }
6276 /* Find ways of folding logical expressions of LHS and RHS:
6277 Try to merge two comparisons to the same innermost item.
6278 Look for range tests like "ch >= '0' && ch <= '9'".
6279 Look for combinations of simple terms on machines with expensive branches
6280 and evaluate the RHS unconditionally.
6282 For example, if we have p->a == 2 && p->b == 4 and we can make an
6283 object large enough to span both A and B, we can do this with a comparison
6284 against the object ANDed with the a mask.
6286 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6287 operations to do this with one comparison.
6289 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6290 function and the one above.
6292 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6293 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6295 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6296 two operands.
6298 We return the simplified tree or 0 if no optimization is possible. */
6300 static tree
6303 {
6304 /* If this is the "or" of two comparisons, we can do something if
6305 the comparisons are NE_EXPR. If this is the "and", we can do something
6306 if the comparisons are EQ_EXPR. I.e.,
6307 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6309 WANTED_CODE is this operation code. For single bit fields, we can
6310 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6311 comparison for one-bit fields. */
6332 /* Start by getting the comparison codes. Fail if anything is volatile.
6333 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6334 it were surrounded with a NE_EXPR. */
6343 {
6347 }
6350 {
6354 }
6365 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6368 {
6371 {
6376 }
6379 {
6385 }
6386 }
6391 /* If the RHS can be evaluated unconditionally and its operands are
6392 simple, it wins to evaluate the RHS unconditionally on machines
6393 with expensive branches. In this case, this isn't a comparison
6394 that can be merged. */
6401 {
6402 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6413 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6423 }
6425 /* See if the comparisons can be merged. Then get all the parameters for
6426 each side. */
6451 /* It must be true that the inner operation on the lhs of each
6452 comparison must be the same if we are to be able to do anything.
6453 Then see if we have constants. If not, the same must be true for
6454 the rhs's. */
6463 {
6466 }
6471 else
6474 /* If either comparison code is not correct for our logical operation,
6475 fail. However, we can convert a one-bit comparison against zero into
6476 the opposite comparison against that bit being set in the field. */
6480 {
6482 {
6483 /* Make the left operand unsigned, since we are only interested
6484 in the value of one bit. Otherwise we are doing the wrong
6485 thing below. */
6488 }
6489 else
6491 }
6493 /* This is analogous to the code for l_const above. */
6495 {
6497 {
6500 }
6501 else
6503 }
6505 /* See if we can find a mode that contains both fields being compared on
6506 the left. If we can't, fail. Otherwise, update all constants and masks
6507 to be relative to a field of that size. */
6521 {
6524 }
6534 {
6543 {
6547 }
6548 }
6550 {
6559 {
6563 }
6564 }
6566 /* If the right sides are not constant, do the same for it. Also,
6567 disallow this optimization if a size, signedness or storage order
6568 mismatch occurs between the left and right sides. */
6570 {
6574 /* Make sure the two fields on the right
6575 correspond to the left without being swapped. */
6592 {
6595 }
6606 /* Make a mask that corresponds to both fields being compared.
6607 Do this for both items being compared. If the operands are the
6608 same size and the bits being compared are in the same position
6609 then we can do this by masking both and comparing the masked
6610 results. */
6617 {
6631 }
6633 /* There is still another way we can do something: If both pairs of
6634 fields being compared are adjacent, we may be able to make a wider
6635 field containing them both.
6637 Note that we still must mask the lhs/rhs expressions. Furthermore,
6638 the mask must be shifted to account for the shift done by
6639 make_bit_field_ref. */
6648 {
6649 tree type;
6667 /* Convert to the smaller type before masking out unwanted bits. */
6670 {
6672 {
6676 }
6678 {
6682 }
6683 }
6692 }
6695 }
6697 /* Handle the case of comparisons with constants. If there is something in
6698 common between the masks, those bits of the constants must be the same.
6699 If not, the condition is always false. Test for this to avoid generating
6700 incorrect code below. */
6705 {
6707 {
6710 }
6711 else
6712 {
6715 }
6716 }
6721 /* Construct the expression we will return. First get the component
6722 reference we will make. Unless the mask is all ones the width of
6723 that field, perform the mask operation. Then compare with the
6724 merged constant. */
6735 }
6736 \f
6737 /* T is an integer expression that is being multiplied, divided, or taken a
6738 modulus (CODE says which and what kind of divide or modulus) by a
6739 constant C. See if we can eliminate that operation by folding it with
6740 other operations already in T. WIDE_TYPE, if non-null, is a type that
6741 should be used for the computation if wider than our type.
6743 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6744 (X * 2) + (Y * 4). We must, however, be assured that either the original
6745 expression would not overflow or that overflow is undefined for the type
6746 in the language in question.
6748 If we return a non-null expression, it is an equivalent form of the
6749 original computation, but need not be in the original type.
6751 We set *STRICT_OVERFLOW_P to true if the return values depends on
6752 signed overflow being undefined. Otherwise we do not change
6753 *STRICT_OVERFLOW_P. */
6755 static tree
6758 {
6759 /* To avoid exponential search depth, refuse to allow recursion past
6760 three levels. Beyond that (1) it's highly unlikely that we'll find
6761 something interesting and (2) we've probably processed it before
6762 when we built the inner expression. */
6765 tree ret;
6770 depth++;
6772 depth--;
6775 }
6777 static tree
6780 {
6792 /* Don't deal with constants of zero here; they confuse the code below. */
6802 /* Note that we need not handle conditional operations here since fold
6803 already handles those cases. So just do arithmetic here. */
6805 {
6807 /* For a constant, we can always simplify if we are a multiply
6808 or (for divide and modulus) if it is a multiple of our constant. */
6812 {
6815 /* If the multiplication overflowed, we lost information on it.
6816 See PR68142 and PR69845. */
6820 }
6826 /* If op0 is an expression ... */
6832 /* ... and has wrapping overflow, and its type is smaller
6833 than ctype, then we cannot pass through as widening. */
6837 /* ... or this is a truncation (t is narrower than op0),
6838 then we cannot pass through this narrowing. */
6841 /* ... or signedness changes for division or modulus,
6842 then we cannot pass through this conversion. */
6846 /* ... or has undefined overflow while the converted to
6847 type has not, we cannot do the operation in the inner type
6848 as that would introduce undefined overflow. */
6853 /* Pass the constant down and see if we can make a simplification. If
6854 we can, replace this expression with the inner simplification for
6855 possible later conversion to our or some other type. */
6866 /* If widening the type changes it from signed to unsigned, then we
6867 must avoid building ABS_EXPR itself as unsigned. */
6869 {
6873 {
6876 }
6878 }
6879 /* If the constant is negative, we cannot simplify this. */
6882 /* FALLTHROUGH */
6884 /* For division and modulus, type can't be unsigned, as e.g.
6885 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6886 For signed types, even with wrapping overflow, this is fine. */
6895 /* If widening the type changes the signedness, then we can't perform
6896 this optimization as that changes the result. */
6900 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6906 {
6913 }
6917 /* If the second operand is constant, this is a multiplication
6918 or floor division, by a power of two, so we can treat it that
6919 way unless the multiplier or divisor overflows. Signed
6920 left-shift overflow is implementation-defined rather than
6921 undefined in C90, so do not convert signed left shift into
6922 multiplication. */
6925 /* const_binop may not detect overflow correctly,
6926 so check for it explicitly here. */
6935 ctype,
6937 t1),
6942 /* See if we can eliminate the operation on both sides. If we can, we
6943 can return a new PLUS or MINUS. If we can't, the only remaining
6944 cases where we can do anything are if the second operand is a
6945 constant. */
6952 /* If not multiplication, we can only do this if both operands
6953 are divisible by c. */
6956 {
6961 }
6963 /* If this was a subtraction, negate OP1 and set it to be an addition.
6964 This simplifies the logic below. */
6966 {
6968 /* If OP1 was not easily negatable, the constant may be OP0. */
6970 {
6973 }
6974 }
6979 /* If either OP1 or C are negative, this optimization is not safe for
6980 some of the division and remainder types while for others we need
6981 to change the code. */
6983 {
6991 }
6993 /* If it's a multiply or a division/modulus operation of a multiple
6994 of our constant, do the operation and verify it doesn't overflow. */
6998 {
7001 /* We allow the constant to overflow with wrapping semantics. */
7005 }
7006 else
7009 /* If we have an unsigned type, we cannot widen the operation since it
7010 will change the result if the original computation overflowed. */
7014 /* The last case is if we are a multiply. In that case, we can
7015 apply the distributive law to commute the multiply and addition
7016 if the multiplication of the constants doesn't overflow
7017 and overflow is defined. With undefined overflow
7018 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
7019 But fold_plusminus_mult_expr would factor back any power-of-two
7020 value so do not distribute in the first place in this case. */
7028 op1);
7033 /* We have a special case here if we are doing something like
7034 (C * 8) % 4 since we know that's zero. */
7037 /* If the multiplication can overflow we cannot optimize this. */
7042 {
7045 }
7047 /* ... fall through ... */
7051 /* If we can extract our operation from the LHS, do so and return a
7052 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
7053 do something only if the second operand is a constant. */
7069 /* If these are the same operation types, we can associate them
7070 assuming no overflow. */
7072 {
7087 }
7089 /* If these operations "cancel" each other, we have the main
7090 optimizations of this pass, which occur when either constant is a
7091 multiple of the other, in which case we replace this with either an
7092 operation or CODE or TCODE.
7094 If we have an unsigned type, we cannot do this since it will change
7095 the result if the original computation overflowed. */
7103 {
7106 {
7112 }
7115 {
7121 }
7122 }
7127 }
7130 }
7131 \f
7132 /* Return a node which has the indicated constant VALUE (either 0 or
7133 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7134 and is of the indicated TYPE. */
7136 tree
7138 {
7147 else
7149 }
7152 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7153 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7154 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7155 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7156 COND is the first argument to CODE; otherwise (as in the example
7157 given here), it is the second argument. TYPE is the type of the
7158 original expression. Return NULL_TREE if no simplification is
7159 possible. */
7161 static tree
7166 {
7174 /* Do not move possibly trapping operations into the conditional as this
7175 pessimizes code and causes gimplification issues when applied late. */
7183 {
7187 /* If this operand throws an expression, then it does not make
7188 sense to try to perform a logical or arithmetic operation
7189 involving it. */
7194 }
7197 {
7202 }
7203 else
7204 /* Detect the case of mixing vector and scalar types - bail out. */
7210 /* This transformation is only worthwhile if we don't have to wrap ARG
7211 in a SAVE_EXPR and the operation can be simplified without recursing
7212 on at least one of the branches once its pushed inside the COND_EXPR. */
7221 {
7225 else
7227 }
7229 {
7233 else
7235 }
7237 /* Check that we have simplified at least one of the branches. */
7242 }
7244 \f
7245 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7247 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7248 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7249 if ARG - ZERO_ARG is the same as X.
7251 If ARG is NULL, check for any value of type TYPE.
7253 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7254 and finite. The problematic cases are when X is zero, and its mode
7255 has signed zeros. In the case of rounding towards -infinity,
7256 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7257 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7259 bool
7262 {
7266 /* Don't allow the fold with -fsignaling-nans. */
7270 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7274 /* There is no case that is safe for all rounding modes. */
7278 /* In a vector or complex, we would need to check the sign of all zeros. */
7284 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7288 /* The mode has signed zeros, and we have to honor their sign.
7289 In this situation, there are only two cases we can return true for.
7290 (i) X - 0 is the same as X with default rounding.
7291 (ii) X + 0 is X when X can't possibly be -0.0. */
7293 }
7295 /* Subroutine of match.pd that optimizes comparisons of a division by
7296 a nonzero integer constant against an integer constant, i.e.
7297 X/C1 op C2.
7299 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7300 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7302 enum tree_code
7305 {
7310 /* We have to do this the hard way to detect unsigned overflow.
7311 prod = int_const_binop (MULT_EXPR, c1, c2); */
7317 {
7321 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7324 }
7326 {
7329 {
7348 }
7349 }
7350 else
7351 {
7352 /* A negative divisor reverses the relational operators. */
7357 {
7376 }
7377 }
7390 }
7393 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7394 equality/inequality test, then return a simplified form of the test
7395 using a sign testing. Otherwise return NULL. TYPE is the desired
7396 result type. */
7398 static tree
7401 tree result_type)
7402 {
7403 /* If this is testing a single bit, we can optimize the test. */
7407 {
7408 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7409 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7413 /* This is only a win if casting to a signed type is cheap,
7414 i.e. when arg00's type is not a partial mode. */
7416 {
7419 result_type,
7422 }
7423 }
7426 }
7428 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7429 equality/inequality test, then return a simplified form of
7430 the test using shifts and logical operations. Otherwise return
7431 NULL. TYPE is the desired result type. */
7433 tree
7436 {
7437 /* If this is testing a single bit, we can optimize the test. */
7441 {
7450 /* First, see if we can fold the single bit test into a sign-bit
7451 test. */
7453 result_type);
7457 /* Otherwise we have (A & C) != 0 where C is a single bit,
7458 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7459 Similarly for (A & C) == 0. */
7461 /* If INNER is a right shift of a constant and it plus BITNUM does
7462 not overflow, adjust BITNUM and INNER. */
7468 {
7471 }
7473 /* If we are going to be able to omit the AND below, we must do our
7474 operations as unsigned. If we must use the AND, we have a choice.
7475 Normally unsigned is faster, but for some machines signed is. */
7493 /* Put the AND last so it can combine with more things. */
7496 /* Make sure to return the proper type. */
7500 }
7502 }
7504 /* Test whether it is preferable to swap two operands, ARG0 and
7505 ARG1, for example because ARG0 is an integer constant and ARG1
7506 isn't. */
7508 bool
7510 {
7524 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7525 for commutative and comparison operators. Ensuring a canonical
7526 form allows the optimizers to find additional redundancies without
7527 having to explicitly check for both orderings. */
7533 /* Put SSA_NAMEs last. */
7539 /* Put variables last. */
7546 }
7549 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7550 means A >= Y && A != MAX, but in this case we know that
7551 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7553 static tree
7555 {
7562 else
7571 {
7574 }
7576 {
7579 }
7580 else
7587 {
7588 /* Convert the pointer types into integer before taking the difference. */
7592 }
7593 else
7600 }
7602 /* Fold a sum or difference of at least one multiplication.
7603 Returns the folded tree or NULL if no simplification could be made. */
7605 static tree
7608 {
7612 /* (A * C) +- (B * C) -> (A+-B) * C.
7613 (A * C) +- A -> A * (C+-1).
7614 We are most concerned about the case where C is a constant,
7615 but other combinations show up during loop reduction. Since
7616 it is not difficult, try all four possibilities. */
7619 {
7622 }
7624 {
7627 }
7628 else
7629 {
7630 /* We cannot generate constant 1 for fract. */
7635 }
7637 {
7640 }
7642 {
7644 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7645 the purpose of this canonicalization. */
7649 {
7652 }
7653 else
7655 }
7656 else
7657 {
7658 /* We cannot generate constant 1 for fract. */
7663 }
7666 /* Prefer factoring a common non-constant. */
7676 /* No identical multiplicands; see if we can find a common
7677 power-of-two factor in non-power-of-two multiplies. This
7678 can help in multi-dimensional array access. */
7680 {
7683 HOST_WIDE_INT tmp;
7685 tree maybe_same;
7687 /* Move min of absolute values to int11. */
7689 {
7694 }
7695 else
7702 /* The remainder should not be a constant, otherwise we
7703 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7704 increased the number of multiplications necessary. */
7706 {
7714 }
7715 }
7722 /* We are neither factoring zero nor minus one. */
7730 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7731 same may be minus one and thus the multiplication may overflow. Perform
7732 the sum operation in an unsigned type. */
7737 /* If the sum evaluated to a constant that is not -INF the multiplication
7738 cannot overflow. */
7745 /* Do not resort to unsigned multiplication because
7746 we lose the no-overflow property of the expression. */
7748 }
7750 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7751 specified by EXPR into the buffer PTR of length LEN bytes.
7752 Return the number of bytes placed in the buffer, or zero
7753 upon failure. */
7755 static int
7757 {
7769 /* Dry run. */
7775 {
7777 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7778 number of bytes. */
7782 {
7789 else
7791 }
7792 else
7796 }
7798 }
7801 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7802 specified by EXPR into the buffer PTR of length LEN bytes.
7803 Return the number of bytes placed in the buffer, or zero
7804 upon failure. */
7806 static int
7808 {
7812 FIXED_VALUE_TYPE value;
7827 }
7830 /* Subroutine of native_encode_expr. Encode the REAL_CST
7831 specified by EXPR into the buffer PTR of length LEN bytes.
7832 Return the number of bytes placed in the buffer, or zero
7833 upon failure. */
7835 static int
7837 {
7843 /* There are always 32 bits in each long, no matter the size of
7844 the hosts long. We handle floating point representations with
7845 up to 192 bits. */
7854 /* Dry run. */
7863 {
7868 {
7875 else
7877 }
7878 else
7879 {
7882 {
7883 /* Reverse bytes within each long, or within the entire float
7884 if it's smaller than a long (for HFmode). */
7887 }
7888 }
7893 }
7895 }
7897 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7898 specified by EXPR into the buffer PTR of length LEN bytes.
7899 Return the number of bytes placed in the buffer, or zero
7900 upon failure. */
7902 static int
7904 {
7906 tree part;
7920 }
7922 /* Like native_encode_vector, but only encode the first COUNT elements.
7923 The other arguments are as for native_encode_vector. */
7925 static int
7928 {
7932 {
7933 /* This is the only case in which elements can be smaller than a byte.
7934 Element 0 is always in the lsb of the containing byte. */
7943 /* Zero the buffer and then set bits later where necessary. */
7952 {
7958 {
7961 }
7962 }
7964 }
7969 {
7971 {
7974 }
7985 }
7987 }
7989 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7990 specified by EXPR into the buffer PTR of length LEN bytes.
7991 Return the number of bytes placed in the buffer, or zero
7992 upon failure. */
7994 static int
7996 {
8001 }
8004 /* Subroutine of native_encode_expr. Encode the STRING_CST
8005 specified by EXPR into the buffer PTR of length LEN bytes.
8006 Return the number of bytes placed in the buffer, or zero
8007 upon failure. */
8009 static int
8011 {
8014 /* Wide-char strings are encoded in target byte-order so native
8015 encoding them is trivial. */
8030 else
8031 {
8034 {
8037 }
8039 }
8041 }
8044 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
8045 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
8046 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
8047 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
8048 sufficient to encode the entire EXPR, or if OFF is out of bounds.
8049 Otherwise, start at byte offset OFF and encode at most LEN bytes.
8050 Return the number of bytes placed in the buffer, or zero upon failure. */
8052 int
8054 {
8055 /* We don't support starting at negative offset and -1 is special. */
8060 {
8081 }
8082 }
8084 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
8085 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
8086 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
8087 machine modes, we can't just use build_nonstandard_integer_type. */
8089 tree
8091 {
8092 machine_mode mode;
8094 {
8101 {
8105 }
8106 }
8112 {
8120 }
8123 }
8125 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8126 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8127 to be non-NULL and OFF zero), then in addition to filling the
8128 bytes pointed by PTR with the value also clear any bits pointed
8129 by MASK that are known to be initialized, keep them as is for
8130 e.g. uninitialized padding bits or uninitialized fields. */
8132 int
8135 {
8138 /* We don't support starting at negative offset and -1 is special. */
8146 {
8150 mask);
8165 {
8166 tree min_index;
8184 {
8189 {
8192 }
8197 else
8201 {
8205 offset_int wpos
8213 offset_int wcount
8220 }
8222 {
8225 offset_int wpos
8233 }
8236 {
8238 {
8249 }
8251 {
8255 }
8256 }
8260 do
8261 {
8266 {
8268 {
8271 fieldsize);
8274 }
8276 ptr
8279 fieldsize,
8282 mask
8286 else
8287 {
8290 }
8291 }
8294 {
8295 /* Partial overlap. */
8301 {
8305 fieldsize);
8306 }
8307 else
8308 {
8312 }
8315 }
8317 }
8319 }
8321 }
8324 {
8334 {
8340 {
8343 }
8346 {
8355 }
8359 else
8363 {
8364 tree fld;
8366 {
8379 }
8381 {
8385 }
8388 {
8389 cnt--;
8395 }
8396 }
8401 {
8414 {
8419 }
8420 }
8421 else
8422 {
8427 }
8432 {
8439 else
8445 }
8454 {
8455 /* FIXME: Handle PDP endian. */
8466 {
8469 }
8470 else
8471 {
8479 else
8480 {
8483 }
8484 }
8494 else
8507 /* If the bitfield does not start at byte boundary, handle
8508 the partial byte at the start. */
8511 {
8513 {
8518 {
8521 else
8523 }
8524 }
8525 else
8526 {
8531 {
8534 else
8538 }
8539 }
8540 }
8541 /* If the bitfield does not end at byte boundary, handle
8542 the partial byte at the end. */
8546 {
8548 {
8555 }
8556 else
8557 {
8564 }
8565 }
8569 {
8574 }
8575 else
8576 {
8577 /* Partial overlap. */
8581 {
8584 }
8588 }
8590 }
8595 {
8598 {
8601 {
8605 }
8608 }
8611 fldsize,
8621 }
8622 else
8623 {
8624 /* Partial overlap. */
8630 {
8634 fieldsize);
8635 }
8636 else
8637 {
8641 }
8644 }
8645 }
8647 }
8649 }
8650 }
8653 /* Subroutine of native_interpret_expr. Interpret the contents of
8654 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8655 If the buffer cannot be interpreted, return NULL_TREE. */
8657 static tree
8659 {
8669 }
8672 /* Subroutine of native_interpret_expr. Interpret the contents of
8673 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8674 If the buffer cannot be interpreted, return NULL_TREE. */
8676 static tree
8678 {
8681 double_int result;
8682 FIXED_VALUE_TYPE fixed_value;
8692 }
8695 /* Subroutine of native_interpret_expr. Interpret the contents of
8696 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8697 If the buffer cannot be interpreted, return NULL_TREE. */
8699 tree
8701 {
8705 /* There are always 32 bits in each long, no matter the size of
8706 the hosts long. We handle floating point representations with
8707 up to 192 bits. */
8708 REAL_VALUE_TYPE r;
8718 {
8719 /* Both OFFSET and BYTE index within a long;
8720 bitpos indexes the whole float. */
8723 {
8730 else
8732 }
8733 else
8734 {
8737 {
8738 /* Reverse bytes within each long, or within the entire float
8739 if it's smaller than a long (for HFmode). */
8742 }
8743 }
8747 }
8751 }
8754 /* Subroutine of native_interpret_expr. Interpret the contents of
8755 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8756 If the buffer cannot be interpreted, return NULL_TREE. */
8758 static tree
8760 {
8775 }
8777 /* Read a vector of type TYPE from the target memory image given by BYTES,
8778 which contains LEN bytes. The vector is known to be encodable using
8779 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8781 Return the vector on success, otherwise return null. */
8783 static tree
8787 {
8791 {
8792 /* This is the only case in which elements can be smaller than a byte.
8793 Element 0 is always in the lsb of the containing byte. */
8800 {
8807 }
8809 }
8817 {
8823 }
8825 }
8827 /* Subroutine of native_interpret_expr. Interpret the contents of
8828 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8829 If the buffer cannot be interpreted, return NULL_TREE. */
8831 static tree
8833 {
8834 tree etype;
8845 }
8848 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8849 the buffer PTR of length LEN as a constant of type TYPE. For
8850 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8851 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8852 return NULL_TREE. */
8854 tree
8856 {
8858 {
8869 {
8870 /* For floating point values in composite modes, punt if this
8871 folding doesn't preserve bit representation. As the mode doesn't
8872 have fixed precision while GCC pretends it does, there could be
8873 valid values that GCC can't really represent accurately.
8874 See PR95450. Even for other modes, e.g. x86 XFmode can have some
8875 bit combinationations which GCC doesn't preserve. */
8885 }
8899 }
8900 }
8902 /* Returns true if we can interpret the contents of a native encoding
8903 as TYPE. */
8905 bool
8907 {
8909 {
8923 }
8924 }
8926 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8927 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8929 tree
8932 {
8935 {
8942 {
8946 }
8951 {
8956 {
8961 }
8965 eltsz);
8969 }
8971 }
8975 {
8983 {
8986 {
8987 poly_int64 bitoffset;
8992 else
9002 }
9003 else
9004 {
9022 HOST_WIDE_INT rpos;
9025 else
9026 {
9029 }
9038 }
9039 }
9042 {
9052 }
9056 {
9061 }
9068 {
9072 /* FIXME: Figure out how to handle PDP endian bitfields. */
9078 else
9082 }
9084 }
9086 }
9088 /* Routines for manipulation of native_encode_expr encoded data if the encoded
9089 or extracted constant positions and/or sizes aren't byte aligned. */
9091 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
9092 bits between adjacent elements. AMNT should be within
9093 [0, BITS_PER_UNIT).
9094 Example, AMNT = 2:
9095 00011111|11100000 << 2 = 01111111|10000000
9096 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
9098 void
9101 {
9110 {
9116 {
9119 }
9120 }
9121 }
9123 /* Like shift_bytes_in_array_left but for big-endian.
9124 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9125 bits between adjacent elements. AMNT should be within
9126 [0, BITS_PER_UNIT).
9127 Example, AMNT = 2:
9128 00011111|11100000 >> 2 = 00000111|11111000
9129 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9131 void
9134 {
9142 {
9149 }
9150 }
9152 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9153 directly on the VECTOR_CST encoding, in a way that works for variable-
9154 length vectors. Return the resulting VECTOR_CST on success or null
9155 on failure. */
9157 static tree
9159 {
9171 /* We can only preserve the semantics of a stepped pattern if the new
9172 vector element is an integer of the same size. */
9177 /* The number of bits needed to encode one element from every pattern
9178 of the original vector. */
9179 unsigned int expr_sequence_bits
9182 /* The number of bits needed to encode one element from every pattern
9183 of the result. */
9184 unsigned int type_sequence_bits
9187 /* Don't try to read more bytes than are available, which can happen
9188 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9189 The general VIEW_CONVERT handling can cope with that case, so there's
9190 no point complicating things here. */
9193 BITS_PER_UNIT);
9198 /* Get enough bytes of EXPR to form the new encoding. */
9206 /* Reencode the bytes as TYPE. */
9210 }
9212 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9213 TYPE at compile-time. If we're unable to perform the conversion
9214 return NULL_TREE. */
9216 static tree
9218 {
9219 /* We support up to 512-bit values (for V8DFmode). */
9223 /* Check that the host and target are sane. */
9236 }
9238 /* Build an expression for the address of T. Folds away INDIRECT_REF
9239 to avoid confusing the gimplify process. */
9241 tree
9243 {
9244 /* The size of the object is not relevant when talking about its address. */
9249 {
9254 }
9257 {
9262 }
9269 {
9274 }
9275 else
9279 }
9281 /* Build an expression for the address of T. */
9283 tree
9285 {
9289 }
9291 /* Fold a unary expression of code CODE and type TYPE with operand
9292 OP0. Return the folded expression if folding is successful.
9293 Otherwise, return NULL_TREE. */
9295 tree
9297 {
9298 tree tem;
9299 tree arg0;
9307 {
9310 {
9311 /* Don't use STRIP_NOPS, because signedness of argument type
9312 matters. */
9314 }
9315 else
9316 {
9317 /* Strip any conversions that don't change the mode. This
9318 is safe for every expression, except for a comparison
9319 expression because its signedness is derived from its
9320 operands.
9322 Note that this is done as an internal manipulation within
9323 the constant folder, in order to find the simplest
9324 representation of the arguments so that their form can be
9325 studied. In any cases, the appropriate type conversions
9326 should be put back in the tree that will get out of the
9327 constant folder. */
9329 }
9332 {
9335 {
9339 }
9340 }
9341 }
9348 {
9355 {
9369 /* If this was a conversion, and all we did was to move into
9370 inside the COND_EXPR, bring it back out. But leave it if
9371 it is a conversion from integer to integer and the
9372 result precision is no wider than a word since such a
9373 conversion is cheap and may be optimized away by combine,
9374 while it couldn't if it were outside the COND_EXPR. Then return
9375 so we don't get into an infinite recursion loop taking the
9376 conversion out and then back in. */
9388 && (INTEGRAL_TYPE_P
9401 }
9402 }
9405 {
9411 CASE_CONVERT:
9415 {
9416 /* If we have (type) (a CMP b) and type is an integral type, return
9417 new expression involving the new type. Canonicalize
9418 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9419 non-integral type.
9420 Do not fold the result as that would not simplify further, also
9421 folding again results in recursions. */
9431 }
9433 /* Handle (T *)&A.B.C for A being of type T and B and C
9434 living at offset zero. This occurs frequently in
9435 C++ upcasting and then accessing the base. */
9439 {
9441 tree offset;
9442 machine_mode mode;
9444 tree base
9448 /* If the reference was to a (constant) zero offset, we can use
9449 the address of the base if it has the same base type
9450 as the result type and the pointer type is unqualified. */
9458 }
9462 /* Detect assigning a bitfield. */
9464 && DECL_BIT_FIELD
9466 {
9467 /* Don't leave an assignment inside a conversion
9468 unless assigning a bitfield. */
9470 /* First do the assignment, then return converted constant. */
9475 }
9477 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9478 constants (if x has signed type, the sign bit cannot be set
9479 in c). This folds extension into the BIT_AND_EXPR.
9480 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9481 very likely don't have maximal range for their precision and this
9482 transformation effectively doesn't preserve non-maximal ranges. */
9486 {
9497 <= HOST_BITS_PER_WIDE_INT
9499 {
9503 cst &= HOST_WIDE_INT_M1U
9507 && !flag_syntax_only
9510 {
9514 }
9515 }
9517 {
9522 }
9523 }
9525 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9526 cast (T1)X will fold away. We assume that this happens when X itself
9527 is a cast. */
9531 {
9535 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9536 when the pointed type needs higher alignment than
9537 the p+ first operand's pointed type. */
9544 /* Similarly, avoid this optimization in GENERIC for -fsanitize=null
9545 when type is a reference type and arg00's type is not,
9546 because arg00 could be validly nullptr and if arg01 doesn't return,
9547 we don't want false positive binding of reference to nullptr. */
9549 && !in_gimple_form
9556 }
9558 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9559 of the same precision, and X is an integer type not narrower than
9560 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9566 {
9572 }
9574 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9575 type of X and Y (integer types only). */
9582 {
9583 /* Be careful not to introduce new overflows. */
9584 tree mult_type;
9587 else
9591 {
9598 }
9599 }
9605 {
9612 }
9623 /* Convert fabs((double)float) into (double)fabsf(float). */
9626 {
9632 targ0));
9633 }
9637 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9656 /* Note that the operand of this must be an int
9657 and its values must be 0 or 1.
9658 ("true" is a fixed value perhaps depending on the language,
9659 but we don't handle values other than 1 correctly yet.) */
9666 /* Fold *&X to X if X is an lvalue. */
9668 {
9675 }
9681 }
9684 /* If the operation was a conversion do _not_ mark a resulting constant
9685 with TREE_OVERFLOW if the original constant was not. These conversions
9686 have implementation defined behavior and retaining the TREE_OVERFLOW
9687 flag here would confuse later passes such as VRP. */
9688 tree
9691 {
9700 }
9702 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9703 operands OP0 and OP1. LOC is the location of the resulting expression.
9704 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9705 Return the folded expression if folding is successful. Otherwise,
9706 return NULL_TREE. */
9707 static tree
9710 {
9711 tree tem;
9713 /* We only do these simplifications if we are optimizing. */
9717 /* Check for things like (A || B) && (A || C). We can convert this
9718 to A || (B && C). Note that either operator can be any of the four
9719 truth and/or operations and the transformation will still be
9720 valid. Also note that we only care about order for the
9721 ANDIF and ORIF operators. If B contains side effects, this
9722 might change the truth-value of A. */
9729 {
9749 /* This case if tricky because we must either have commutative
9750 operators or else A10 must not have side-effects. */
9756 a01);
9757 }
9759 /* See if we can build a range comparison. */
9765 {
9769 }
9773 {
9777 }
9779 /* Check for the possibility of merging component references. If our
9780 lhs is another similar operation, try to merge its rhs with our
9781 rhs. Then try to merge our lhs and rhs. */
9792 logical_op_non_short_circuit
9800 {
9807 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9808 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9809 We don't want to pack more than two leafs to a non-IF AND/OR
9810 expression.
9811 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9812 equal to IF-CODE, then we don't want to add right-hand operand.
9813 If the inner right-hand side of left-hand operand has
9814 side-effects, or isn't simple, then we can't add to it,
9815 as otherwise we might destroy if-sequence. */
9818 /* Needed for sequence points to handle trappings, and
9819 side-effects. */
9821 {
9823 arg1);
9825 tem);
9826 }
9827 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9828 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9831 /* Needed for sequence points to handle trappings, and
9832 side-effects. */
9834 {
9839 }
9840 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9841 into (A OR B).
9842 For sequence point consistancy, we need to check for trapping,
9843 and side-effects. */
9847 }
9850 }
9852 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9853 by changing CODE to reduce the magnitude of constants involved in
9854 ARG0 of the comparison.
9855 Returns a canonicalized comparison tree if a simplification was
9856 possible, otherwise returns NULL_TREE.
9857 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9858 valid if signed overflow is undefined. */
9860 static tree
9864 {
9869 /* Match A +- CST code arg1. We can change this only if overflow
9870 is undefined. */
9873 /* In principle pointers also have undefined overflow behavior,
9874 but that causes problems elsewhere. */
9881 /* Identify the constant in arg0 and its sign. */
9885 /* Overflowed constants and zero will cause problems. */
9890 /* See if we can reduce the magnitude of the constant in
9891 arg0 by changing the comparison code. */
9892 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9896 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9900 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9904 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9908 else
9912 /* Now build the constant reduced in magnitude. But not if that
9913 would produce one outside of its types range. */
9929 }
9931 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9932 overflow further. Try to decrease the magnitude of constants involved
9933 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9934 and put sole constants at the second argument position.
9935 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9937 static tree
9940 {
9941 tree t;
9946 /* Try canonicalization by simplifying arg0. */
9951 {
9955 }
9957 /* Try canonicalization by simplifying arg1 using the swapped
9958 comparison. */
9966 }
9968 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9969 space. This is used to avoid issuing overflow warnings for
9970 expressions like &p->x which cannot wrap. */
9972 static bool
9974 {
9981 poly_wide_int wi_offset;
9987 else
9992 precision);
10007 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
10008 array. */
10017 }
10019 /* Return a positive integer when the symbol DECL is known to have
10020 a nonzero address, zero when it's known not to (e.g., it's a weak
10021 symbol), and a negative integer when the symbol is not yet in the
10022 symbol table and so whether or not its address is zero is unknown.
10023 For function local objects always return positive integer. */
10024 static int
10026 {
10027 /* Normally, don't do anything for variables and functions before symtab is
10028 built; it is quite possible that DECL will be declared weak later.
10029 But if folding_initializer, we need a constant answer now, so create
10030 the symtab entry and prevent later weak declaration. */
10033 = (folding_initializer
10038 /* Function local objects are never NULL. */
10046 }
10048 /* Subroutine of fold_binary. This routine performs all of the
10049 transformations that are common to the equality/inequality
10050 operators (EQ_EXPR and NE_EXPR) and the ordering operators
10051 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
10052 fold_binary should call fold_binary. Fold a comparison with
10053 tree code CODE and type TYPE with operands OP0 and OP1. Return
10054 the folded comparison or NULL_TREE. */
10056 static tree
10059 {
10069 /* For comparisons of pointers we can decompose it to a compile time
10070 comparison of the base objects and the offsets into the object.
10071 This requires at least one operand being an ADDR_EXPR or a
10072 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
10078 {
10081 machine_mode mode;
10085 /* Get base and offset for the access. Strip ADDR_EXPR for
10086 get_inner_reference, but put it back by stripping INDIRECT_REF
10087 off the base object if possible. indirect_baseN will be true
10088 if baseN is not an address but refers to the object itself. */
10091 {
10092 base0
10098 else
10100 }
10102 {
10106 {
10107 base0
10113 else
10115 }
10118 else
10122 {
10129 }
10130 }
10134 {
10135 base1
10141 else
10143 }
10145 {
10149 {
10150 base1
10156 else
10158 }
10161 else
10165 {
10172 }
10173 }
10175 /* If we have equivalent bases we might be able to simplify. */
10179 {
10180 /* We can fold this expression to a constant if the non-constant
10181 offset parts are equal. */
10185 && (equality_code
10186 || (indirect_base0
10189 {
10195 "occur when comparing P +- C1 with "
10197 WARN_STRICT_OVERFLOW_CONDITIONAL);
10200 {
10238 }
10239 }
10240 /* We can simplify the comparison to a comparison of the variable
10241 offset parts if the constant offset parts are equal.
10242 Be careful to use signed sizetype here because otherwise we
10243 mess with array offsets in the wrong way. This is possible
10244 because pointer arithmetic is restricted to retain within an
10245 object and overflow on pointer differences is undefined as of
10246 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10248 && (equality_code
10249 || (indirect_base0
10252 {
10253 /* By converting to signed sizetype we cover middle-end pointer
10254 arithmetic which operates on unsigned pointer types of size
10255 type size and ARRAY_REF offsets which are properly sign or
10256 zero extended from their type in case it is narrower than
10257 sizetype. */
10260 else
10264 else
10271 "occur when comparing P +- C1 with "
10273 WARN_STRICT_OVERFLOW_COMPARISON);
10276 }
10277 }
10278 /* For equal offsets we can simplify to a comparison of the
10279 base addresses. */
10281 && (indirect_base0
10283 && (indirect_base1
10288 {
10294 }
10295 /* Comparison between an ordinary (non-weak) symbol and a null
10296 pointer can be eliminated since such symbols must have a non
10297 null address. In C, relational expressions between pointers
10298 to objects and null pointers are undefined. The results
10299 below follow the C++ rules with the additional property that
10300 every object pointer compares greater than a null pointer.
10301 */
10304 /* Avoid folding references to struct members at offset 0 to
10305 prevent tests like '&ptr->firstmember == 0' from getting
10306 eliminated. When ptr is null, although the -> expression
10307 is strictly speaking invalid, GCC retains it as a matter
10308 of QoI. See PR c/44555. */
10311 && indirect_base0
10312 /* The caller guarantees that when one of the arguments is
10313 constant (i.e., null in this case) it is second. */
10315 {
10317 {
10328 }
10329 }
10330 }
10332 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10333 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10334 the resulting offset is smaller in absolute value than the
10335 original one and has the same sign. */
10344 {
10349 tree cst;
10351 "occur when combining constants around "
10354 /* Put the constant on the side where it doesn't overflow and is
10355 of lower absolute value and of same sign than before. */
10362 {
10365 variable1,
10369 }
10377 {
10383 variable2);
10384 }
10385 }
10391 /* If we are comparing an expression that just has comparisons
10392 of two integer values, arithmetic expressions of those comparisons,
10393 and constants, we can simplify it. There are only three cases
10394 to check: the two values can either be equal, the first can be
10395 greater, or the second can be greater. Fold the expression for
10396 those three values. Since each value must be 0 or 1, we have
10397 eight possibilities, each of which corresponds to the constant 0
10398 or 1 or one of the six possible comparisons.
10400 This handles common cases like (a > b) == 0 but also handles
10401 expressions like ((x > y) - (y > x)) > 0, which supposedly
10402 occur in macroized code. */
10405 {
10409 /* Don't handle degenerate cases here; they should already
10410 have been handled anyway. */
10419 {
10423 /* We can't just pass T to eval_subst in case cval1 or cval2
10424 was the same as ARG1. */
10426 tree high_result
10430 arg1);
10431 tree equal_result
10435 arg1);
10436 tree low_result
10440 arg1);
10442 /* All three of these results should be 0 or 1. Confirm they are.
10443 Then use those values to select the proper code to use. */
10448 {
10449 /* Make a 3-bit mask with the high-order bit being the
10450 value for `>', the next for '=', and the low for '<'. */
10454 {
10456 /* Always false. */
10477 /* Always true. */
10479 }
10482 }
10483 }
10484 }
10487 }
10490 /* Subroutine of fold_binary. Optimize complex multiplications of the
10491 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10492 argument EXPR represents the expression "z" of type TYPE. */
10494 static tree
10496 {
10501 {
10504 }
10506 {
10509 }
10510 else
10511 {
10515 }
10524 }
10527 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10528 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10529 true if successful. */
10531 static bool
10533 {
10538 {
10541 }
10543 {
10549 else
10551 }
10552 else
10558 }
10560 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10561 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10562 NULL_TREE otherwise. */
10564 tree
10566 {
10587 {
10588 HOST_WIDE_INT index;
10594 }
10597 {
10603 }
10604 else
10606 }
10608 /* Try to fold a pointer difference of type TYPE two address expressions of
10609 array references AREF0 and AREF1 using location LOC. Return a
10610 simplified expression for the difference or NULL_TREE. */
10612 static tree
10616 {
10621 /* If the bases are array references as well, recurse. If the bases
10622 are pointer indirections compute the difference of the pointers.
10623 If the bases are equal, we are set. */
10626 && (base_offset
10628 use_pointer_diff)))
10631 && (base_offset
10632 = use_pointer_diff
10642 {
10648 base_offset,
10651 }
10653 }
10655 /* If the real or vector real constant CST of type TYPE has an exact
10656 inverse, return it, else return NULL. */
10658 tree
10660 {
10661 REAL_VALUE_TYPE r;
10662 tree unit_type;
10663 machine_mode mode;
10666 {
10676 {
10680 tree_vector_builder elts;
10685 {
10690 }
10693 }
10697 }
10698 }
10700 /* Mask out the tz least significant bits of X of type TYPE where
10701 tz is the number of trailing zeroes in Y. */
10702 static wide_int
10704 {
10709 }
10711 /* Return true when T is an address and is known to be nonzero.
10712 For floating point we further ensure that T is not denormal.
10713 Similar logic is present in nonzero_address in rtlanal.h.
10715 If the return value is based on the assumption that signed overflow
10716 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10717 change *STRICT_OVERFLOW_P. */
10719 static bool
10721 {
10725 /* Doing something useful for floating point would need more work. */
10731 {
10734 strict_overflow_p);
10740 strict_overflow_p);
10748 }
10751 {
10754 strict_overflow_p);
10762 strict_overflow_p);
10776 strict_overflow_p);
10780 strict_overflow_p);
10783 {
10795 }
10799 }
10801 }
10803 /* Return true when T is an address and is known to be nonzero.
10804 Handle warnings about undefined signed overflow. */
10806 bool
10808 {
10815 "determining that expression is always "
10817 WARN_STRICT_OVERFLOW_MISC);
10819 }
10821 /* Return true if T is known not to be equal to an integer W. */
10823 bool
10825 {
10826 int_range_max vr;
10828 {
10838 else
10844 /* If T has some known zero bits and W has any of those bits set,
10845 then T is known not to be equal to W. */
10853 }
10854 }
10856 /* Fold a binary expression of code CODE and type TYPE with operands
10857 OP0 and OP1. LOC is the location of the resulting expression.
10858 Return the folded expression if folding is successful. Otherwise,
10859 return NULL_TREE. */
10861 tree
10864 {
10879 /* Strip any conversions that don't change the mode. This is
10880 safe for every expression, except for a comparison expression
10881 because its signedness is derived from its operands. So, in
10882 the latter case, only strip conversions that don't change the
10883 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10884 preserved.
10886 Note that this is done as an internal manipulation within the
10887 constant folder, in order to find the simplest representation
10888 of the arguments so that their form can be studied. In any
10889 cases, the appropriate type conversions should be put back in
10890 the tree that will get out of the constant folder. */
10893 {
10896 }
10897 else
10898 {
10901 }
10903 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10904 constant but we can't do arithmetic on them. */
10906 {
10909 {
10913 }
10914 }
10916 /* If this is a commutative operation, and ARG0 is a constant, move it
10917 to ARG1 to reduce the number of tests below. */
10922 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10923 to ARG1 to reduce the number of tests below. */
10932 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10934 First check for cases where an arithmetic operation is applied to a
10935 compound, conditional, or comparison operation. Push the arithmetic
10936 operation inside the compound or conditional to see if any folding
10937 can then be done. Convert comparison to conditional for this purpose.
10938 The also optimizes non-constant cases that used to be done in
10939 expand_expr.
10941 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10942 one of the operands is a comparison and the other is a comparison, a
10943 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10944 code below would make the expression more complex. Change it to a
10945 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10946 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10959 {
10963 boolean_type_node,
10971 }
10975 {
10977 {
10982 tem);
10983 }
10985 {
10990 tem);
10991 }
10996 {
11002 }
11007 {
11013 }
11014 }
11017 {
11019 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
11022 {
11028 }
11030 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
11033 {
11034 tree base;
11035 poly_int64 coffset;
11044 }
11049 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
11055 arg1),
11057 arg0)));
11063 {
11064 /* X + (X / CST) * -CST is X % CST. */
11069 {
11078 cst0));
11079 }
11080 }
11082 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
11083 one. Make sure the type is not saturating and has the signedness of
11084 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11085 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11092 {
11096 }
11099 {
11100 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
11101 (plus (plus (mult) (mult)) (foo)) so that we can
11102 take advantage of the factoring cases below. */
11111 {
11117 else
11130 parg0),
11132 marg)),
11136 return
11142 parg1)));
11143 }
11144 }
11145 else
11146 {
11147 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11148 to __complex__ ( x, y ). This is not the same for SNaNs or
11149 if signed zeros are involved. */
11153 {
11160 {
11164 {
11170 }
11172 {
11178 }
11179 }
11180 }
11182 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11183 We associate floats only if the user has specified
11184 -fassociative-math. */
11188 {
11193 {
11194 tree tree0;
11197 }
11198 }
11199 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11200 We associate floats only if the user has specified
11201 -fassociative-math. */
11205 {
11210 {
11211 tree tree0;
11214 }
11215 }
11216 }
11218 bit_rotate:
11219 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11220 is a rotate of A by C1 bits. */
11221 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11222 is a rotate of A by B bits.
11223 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11224 though in this case CODE must be | and not + or ^, otherwise
11225 it doesn't return A when B is 0. */
11226 {
11228 tree rtype;
11237 /* Only create rotates in complete modes. Other cases are not
11238 expanded properly. */
11241 {
11254 {
11259 }
11264 {
11267 code0 == LSHIFT_EXPR
11270 }
11272 {
11282 {
11286 orig_tree01);
11288 }
11289 }
11293 {
11304 {
11308 orig_tree01);
11310 }
11311 }
11312 }
11313 }
11315 associate:
11316 /* In most languages, can't associate operations on floats through
11317 parentheses. Rather than remember where the parentheses were, we
11318 don't associate floats at all, unless the user has specified
11319 -fassociative-math.
11320 And, we need to make sure type is not saturating. */
11325 {
11331 /* Split both trees into variables, constants, and literals. Then
11332 associate each group together, the constants with literals,
11333 then the result with variables. This increases the chances of
11334 literals being recombined later and of generating relocatable
11335 expressions for the sum of a constant and literal. */
11343 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11347 /* With undefined overflow prefer doing association in a type
11348 which wraps on overflow, if that is one of the operand types. */
11351 {
11359 }
11361 /* With undefined overflow we can only associate constants with one
11362 variable, and constants whose association doesn't overflow. */
11365 {
11367 {
11368 /* ??? If split_tree would handle NEGATE_EXPR we could
11369 simply reject these cases and the allowed cases would
11370 be the var0/minus_var1 ones. */
11376 {
11379 }
11386 {
11389 }
11395 /* The only case we can still associate with two variables
11396 is if they cancel out. */
11400 }
11406 }
11408 /* Only do something if we found more than two objects. Otherwise,
11409 nothing has changed and we risk infinite recursion. */
11417 {
11429 {
11433 }
11435 {
11439 }
11441 /* Preserve the MINUS_EXPR if the negative part of the literal is
11442 greater than the positive part. Otherwise, the multiplicative
11443 folding code (i.e extract_muldiv) may be fooled in case
11444 unsigned constants are subtracted, like in the following
11445 example: ((X*2 + 4) - 8U)/2. */
11447 {
11451 /* But avoid ending up with only negated parts. */
11453 {
11457 }
11458 else
11459 {
11463 }
11464 }
11466 /* Don't introduce overflows through reassociation. */
11471 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11478 /* Eliminate minus_con0. */
11480 {
11487 else
11490 }
11492 /* Eliminate minus_var0. */
11494 {
11498 else
11501 }
11503 return
11506 }
11507 }
11513 /* Fold &a[i] - &a[j] to i-j. */
11518 {
11522 code
11526 }
11528 /* Further transformations are not for pointers. */
11532 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11535 /* If arg0 is e.g. unsigned int and type is int, then this could
11536 introduce UB, because if A is INT_MIN at runtime, the original
11537 expression can be well defined while the latter is not.
11538 See PR83269. */
11547 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11548 __complex__ ( x, -y ). This is not the same for SNaNs or if
11549 signed zeros are involved. */
11553 {
11560 {
11564 {
11566 arg1r ? arg1r
11571 }
11573 {
11577 arg1i ? arg1i
11580 }
11581 }
11582 }
11584 /* A - B -> A + (-B) if B is easily negatable. */
11588 /* Avoid this transformation if B is a positive REAL_CST. */
11596 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11597 one. Make sure the type is not saturating and has the signedness of
11598 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11599 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11606 {
11610 }
11616 {
11617 /* Transform x * -C into -x * C if x is easily negatable. */
11632 {
11635 "occur when simplifying "
11637 WARN_STRICT_OVERFLOW_MISC);
11639 }
11641 /* Optimize z * conj(z) for integer complex numbers. */
11648 }
11649 else
11650 {
11651 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11652 This is not the same for NaNs or if signed zeros are
11653 involved. */
11659 {
11662 return
11668 return
11673 }
11675 /* Optimize z * conj(z) for floating point complex numbers.
11676 Guarded by flag_unsafe_math_optimizations as non-finite
11677 imaginary components don't produce scalar results. */
11686 }
11690 /* Canonicalize (X & C1) | C2. */
11694 {
11699 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11707 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11709 {
11712 }
11714 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11715 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11716 mode which allows further optimizations. */
11721 {
11726 {
11729 }
11730 }
11733 {
11738 }
11739 }
11741 /* See if this can be simplified into a rotate first. If that
11742 is unsuccessful continue in the association code. */
11746 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11754 /* See if this can be simplified into a rotate first. If that
11755 is unsuccessful continue in the association code. */
11759 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11764 {
11765 tree tem2;
11772 }
11773 /* Fold ~X & 1 as (X & 1) == 0. */
11777 {
11778 tree tem2;
11785 }
11786 /* Fold !X & 1 as X == 0. */
11789 {
11793 }
11795 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11796 multiple of 1 << CST. */
11798 {
11805 }
11807 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11808 bits from CST2. */
11812 {
11814 wide_int masked
11821 {
11822 /* Avoid the transform if arg1 is a mask of some
11823 mode which allows further optimizations. */
11830 }
11831 }
11833 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11836 {
11841 return
11843 }
11848 /* Don't touch a floating-point divide by zero unless the mode
11849 of the constant can represent infinity. */
11855 /* (-A) / (-B) -> A / B */
11867 /* Fall through */
11870 /* Simplify A / (B << N) where A and B are positive and B is
11871 a power of 2, to A >> (N + log2(B)). */
11876 {
11879 {
11887 WARN_STRICT_OVERFLOW_MISC);
11893 }
11894 }
11896 /* Fall through */
11904 /* Convert -A / -B to A / B when the type is signed and overflow is
11905 undefined. */
11909 {
11912 "when distributing negation across "
11914 WARN_STRICT_OVERFLOW_MISC);
11919 }
11923 {
11926 "when distributing negation across "
11928 WARN_STRICT_OVERFLOW_MISC);
11933 }
11935 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11936 operation, EXACT_DIV_EXPR.
11938 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11939 At one time others generated faster code, it's not clear if they do
11940 after the last round to changes to the DIV code in expmed.cc. */
11951 {
11955 WARN_STRICT_OVERFLOW_MISC);
11957 }
11969 {
11973 WARN_STRICT_OVERFLOW_MISC);
11975 }
11983 /* Since negative shift count is not well-defined,
11984 don't try to compute it in the compiler. */
11990 /* If we have a rotate of a bit operation with the rotate count and
11991 the second operand of the bit operation both constant,
11992 permute the two operations. */
11998 {
12006 }
12008 /* Two consecutive rotates adding up to the some integer
12009 multiple of the precision of the type can be ignored. */
12025 /* Note that the operands of this must be ints
12026 and their values must be 0 or 1.
12027 ("true" is a fixed value perhaps depending on the language.) */
12028 /* If first arg is constant zero, return it. */
12031 /* FALLTHRU */
12033 /* If either arg is constant true, drop it. */
12037 /* Preserve sequence points. */
12040 /* If second arg is constant zero, result is zero, but first arg
12041 must be evaluated. */
12044 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
12045 case will be handled here. */
12049 /* !X && X is always false. */
12053 /* X && !X is always false. */
12058 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
12059 means A >= Y && A != MAX, but in this case we know that
12060 A < X <= MAX. */
12064 {
12076 }
12085 /* Note that the operands of this must be ints
12086 and their values must be 0 or true.
12087 ("true" is a fixed value perhaps depending on the language.) */
12088 /* If first arg is constant true, return it. */
12091 /* FALLTHRU */
12093 /* If either arg is constant zero, drop it. */
12097 /* Preserve sequence points. */
12100 /* If second arg is constant true, result is true, but we must
12101 evaluate first arg. */
12104 /* Likewise for first arg, but note this only occurs here for
12105 TRUTH_OR_EXPR. */
12109 /* !X || X is always true. */
12113 /* X || !X is always true. */
12118 /* (X && !Y) || (!X && Y) is X ^ Y */
12121 {
12138 }
12147 /* If the second arg is constant zero, drop it. */
12150 /* If the second arg is constant true, this is a logical inversion. */
12152 {
12155 }
12156 /* Identical arguments cancel to zero. */
12160 /* !X ^ X is always true. */
12165 /* X ^ !X is always true. */
12181 /* bool_var != 1 becomes !bool_var. */
12188 /* bool_var == 0 becomes !bool_var. */
12195 /* !exp != 0 becomes !exp */
12200 /* If this is an EQ or NE comparison with zero and ARG0 is
12201 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12202 two operations, but the latter can be done in one less insn
12203 on machines that have only two-operand insns or on which a
12204 constant cannot be the first operand. */
12207 {
12212 {
12220 }
12223 {
12231 }
12232 }
12234 /* If this is a comparison of a field, we may be able to simplify it. */
12237 /* Handle the constant case even without -O
12238 to make sure the warnings are given. */
12240 {
12244 }
12246 /* Optimize comparisons of strlen vs zero to a compare of the
12247 first character of the string vs zero. To wit,
12248 strlen(ptr) == 0 => *ptr == 0
12249 strlen(ptr) != 0 => *ptr != 0
12250 Other cases should reduce to one of these two (or a constant)
12251 due to the return value of strlen being unsigned. */
12253 {
12261 {
12262 tree ptrtype
12264 TYPE_QUAL_CONST));
12270 }
12271 }
12273 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12274 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12278 {
12283 {
12285 {
12288 }
12291 }
12292 }
12294 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12295 (X & C) == 0 when C is a single bit. */
12300 {
12307 arg1));
12308 }
12310 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12311 constant C is a power of two, i.e. a single bit. */
12318 {
12322 }
12324 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12325 when is C is a power of two, i.e. a single bit. */
12332 {
12338 }
12342 {
12345 }
12349 {
12356 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12357 operand_equal_p guarantees no side-effects so we don't need
12358 to use omit_one_operand on Z. */
12362 arg10));
12366 arg11));
12370 arg10));
12374 arg11));
12376 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12379 {
12385 }
12386 }
12388 /* Attempt to simplify equality/inequality comparisons of complex
12389 values. Only lower the comparison if the result is known or
12390 can be simplified to a single scalar comparison. */
12395 {
12400 {
12403 }
12404 else
12405 {
12408 }
12411 {
12414 }
12415 else
12416 {
12419 }
12423 {
12425 {
12430 }
12431 else
12432 {
12437 }
12438 }
12442 {
12444 {
12449 }
12450 else
12451 {
12456 }
12457 }
12458 }
12470 /* Transform comparisons of the form X +- C CMP X. */
12475 {
12480 /* (X - c) > X becomes false. */
12486 /* Likewise (X + c) < X becomes false. */
12492 /* Convert (X - c) <= X to true. */
12499 /* Convert (X + c) >= X to true. */
12505 }
12507 /* If we are comparing an ABS_EXPR with a constant, we can
12508 convert all the cases into explicit comparisons, but they may
12509 well not be faster than doing the ABS and one comparison.
12510 But ABS (X) <= C is a range comparison, which becomes a subtraction
12511 and a comparison, and is probably faster. */
12525 /* Convert ABS_EXPR<x> >= 0 to true. */
12532 {
12535 "when simplifying comparison of "
12537 WARN_STRICT_OVERFLOW_CONDITIONAL);
12540 arg0);
12541 }
12543 /* Convert ABS_EXPR<x> < 0 to false. */
12548 {
12551 "when simplifying comparison of "
12553 WARN_STRICT_OVERFLOW_CONDITIONAL);
12556 arg0);
12557 }
12559 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12560 and similarly for >= into !=. */
12570 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12571 otherwise Y might be >= # of bits in X's type and thus e.g.
12572 (unsigned char) (1 << Y) for Y 15 might be 0.
12573 If the cast is widening, then 1 << Y should have unsigned type,
12574 otherwise if Y is number of bits in the signed shift type minus 1,
12575 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12576 31 might be 0xffffffff80000000. */
12589 {
12595 }
12607 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12608 {
12620 }
12625 /* When pedantic, a compound expression can be neither an lvalue
12626 nor an integer constant expression. */
12629 /* Don't let (0, 0) be null pointer constant. */
12637 }
12639 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12640 ((A & N) + B) & M -> (A + B) & M
12641 Similarly if (N & M) == 0,
12642 ((A | N) + B) & M -> (A + B) & M
12643 and for - instead of + (or unary - instead of +)
12644 and/or ^ instead of |.
12645 If B is constant and (B & M) == 0, fold into A & M.
12647 This function is a helper for match.pd patterns. Return non-NULL
12648 type in which the simplified operation should be performed only
12649 if any optimization is possible.
12651 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12652 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12653 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12654 +/-. */
12655 tree
12660 {
12675 wide_int cst0;
12677 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12678 arg1 (M) is == (1LL << cst) - 1.
12679 Store C into PMOP[0] and D into PMOP[1]. */
12686 {
12693 {
12696 }
12699 /* If C or D is of the form (A & N) where
12700 (N & M) == M, or of the form (A | N) or
12701 (A ^ N) where (N & M) == 0, replace it with A. */
12707 /* If C or D is a N where (N & M) == 0, it can be
12708 omitted (replaced with 0). */
12713 /* Similarly, with C - N where (-N & M) == 0. */
12721 }
12723 /* Only build anything new if we optimized one or both arguments above. */
12729 else
12731 }
12733 /* Used by contains_label_[p1]. */
12735 struct contains_label_data
12736 {
12739 };
12741 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12742 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12743 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12745 static tree
12747 {
12750 {
12761 {
12769 }
12778 }
12779 }
12781 /* Return whether the sub-tree ST contains a label which is accessible from
12782 outside the sub-tree. */
12784 static bool
12786 {
12790 }
12792 /* Fold a ternary expression of code CODE and type TYPE with operands
12793 OP0, OP1, and OP2. Return the folded expression if folding is
12794 successful. Otherwise, return NULL_TREE. */
12796 tree
12799 {
12800 tree tem;
12807 /* If this is a commutative operation, and OP0 is a constant, move it
12808 to OP1 to reduce the number of tests below. */
12817 /* Strip any conversions that don't change the mode. This is safe
12818 for every expression, except for a comparison expression because
12819 its signedness is derived from its operands. So, in the latter
12820 case, only strip conversions that don't change the signedness.
12822 Note that this is done as an internal manipulation within the
12823 constant folder, in order to find the simplest representation of
12824 the arguments so that their form can be studied. In any cases,
12825 the appropriate type conversions should be put back in the tree
12826 that will get out of the constant folder. */
12828 {
12831 }
12834 {
12837 }
12840 {
12843 }
12846 {
12850 {
12856 }
12861 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12862 so all simple results must be passed through pedantic_non_lvalue. */
12864 {
12867 /* Only optimize constant conditions when the selected branch
12868 has the same type as the COND_EXPR. This avoids optimizing
12869 away "c ? x : throw", where the throw has a void type.
12870 Avoid throwing away that operand which contains label. */
12877 }
12879 {
12886 {
12889 {
12897 }
12902 }
12903 }
12905 /* If we have A op B ? A : C, we may be able to convert this to a
12906 simpler expression, depending on the operation and the values
12907 of B and C. Signed zeros prevent all of these transformations,
12908 for reasons given above each one.
12910 Also try swapping the arguments and inverting the conditional. */
12914 {
12921 }
12926 {
12933 arg00,
12934 arg01,
12938 }
12940 /* If the second operand is simpler than the third, swap them
12941 since that produces better jump optimization results. */
12944 {
12946 /* See if this can be inverted. If it can't, possibly because
12947 it was a floating-point inequality comparison, don't do
12948 anything. */
12952 }
12954 /* Convert A ? 1 : 0 to simply A. */
12959 /* If we try to convert OP0 to our type, the
12960 call to fold will try to move the conversion inside
12961 a COND, which will recurse. In that case, the COND_EXPR
12962 is probably the best choice, so leave it alone. */
12966 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12967 over COND_EXPR in cases such as floating point comparisons. */
12976 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12981 {
12982 /* sign_bit_p looks through both zero and sign extensions,
12983 but for this optimization only sign extensions are
12984 usable. */
12987 {
12990 {
12993 }
12995 }
12996 /* sign_bit_p only checks ARG1 bits within A's precision.
12997 If <sign bit of A> has wider type than A, bits outside
12998 of A's precision in <sign bit of A> need to be checked.
12999 If they are all 0, this optimization needs to be done
13000 in unsigned A's type, if they are all 1 in signed A's type,
13001 otherwise this can't be done. */
13007 {
13009 tree tem_type;
13022 {
13025 }
13027 {
13030 }
13031 else
13033 }
13036 return
13042 arg1)));
13043 }
13045 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13046 already handled above. */
13051 {
13061 op1);
13062 }
13064 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13065 is probably obsolete because the first operand should be a
13066 truth value (that's why we have the two cases above), but let's
13067 leave it in until we can confirm this for all front-ends. */
13075 /* operand_equal_p compares just value, not precision, so e.g.
13076 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13077 second operand 32-bit -128, which is not a power of two (or vice
13078 versa. */
13082 /* Disable the transformations below for vectors, since
13083 fold_binary_op_with_conditional_arg may undo them immediately,
13084 yielding an infinite loop. */
13088 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13097 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13102 {
13104 /* Only perform transformation if ARG0 is easily inverted. */
13108 ? BIT_IOR_EXPR
13111 op1);
13112 }
13114 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13119 {
13121 /* Only perform transformation if ARG0 is easily inverted. */
13127 op2);
13128 }
13130 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13142 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13143 of fold_ternary on them. */
13153 {
13155 unsigned HOST_WIDE_INT width
13166 {
13171 {
13173 {
13178 }
13184 }
13185 }
13186 }
13188 /* On constants we can use native encode/interpret to constant
13189 fold (nearly) all BIT_FIELD_REFs. */
13195 {
13198 /* Limit us to a reasonable amount of work. To relax the
13199 other limitations we need bit-shifting of the buffer
13200 and rounding up the size. */
13204 {
13206 unsigned HOST_WIDE_INT len
13211 {
13216 }
13217 }
13218 }
13223 /* Perform constant folding of BIT_INSERT_EXPR. */
13227 {
13228 /* Build a vector of integers from the tree mask. */
13229 vec_perm_builder builder;
13233 /* Create a vec_perm_indices for the integer vector. */
13238 }
13242 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13245 {
13251 wide_int tem2
13255 }
13260 {
13262 unsigned HOST_WIDE_INT elsize
13265 {
13271 {
13277 }
13278 }
13279 }
13285 }
13287 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13288 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13289 constructor element index of the value returned. If the element is
13290 not found NULL_TREE is returned and *CTOR_IDX is updated to
13291 the index of the element after the ACCESS_INDEX position (which
13292 may be outside of the CTOR array). */
13294 tree
13297 {
13303 {
13306 {
13307 /* Static constructors for variably sized objects makes no sense. */
13310 /* ??? When it is obvious that the range is signed, treat it so. */
13315 {
13317 low_bound
13319 SIGNED);
13320 }
13321 else
13322 {
13325 }
13326 }
13327 }
13331 index_sgn);
13343 {
13344 /* Array constructor might explicitly set index, or specify a range,
13345 or leave index NULL meaning that it is next index after previous
13346 one. */
13348 {
13350 max_index = index
13352 else
13353 {
13356 index_sgn);
13357 max_index
13359 index_sgn);
13361 }
13362 }
13364 {
13370 }
13371 else
13374 /* Do we have match? */
13376 {
13378 {
13382 }
13383 }
13385 /* We're past the element we search for. Note during parsing
13386 the elements might not be sorted.
13387 ??? We should use a binary search and a flag on the
13388 CONSTRUCTOR as to whether elements are sorted in declaration
13389 order. */
13391 }
13395 }
13397 /* Perform constant folding and related simplification of EXPR.
13398 The related simplifications include x*1 => x, x*0 => 0, etc.,
13399 and application of the associative law.
13400 NOP_EXPR conversions may be removed freely (as long as we
13401 are careful not to change the type of the overall expression).
13402 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13403 but we can constant-fold them if they have constant operands. */
13405 #ifdef ENABLE_FOLD_CHECKING
13406 # define fold(x) fold_1 (x)
13408 static
13409 #endif
13410 tree
13412 {
13416 tree tem;
13419 /* Return right away if a constant. */
13423 /* CALL_EXPR-like objects with variable numbers of operands are
13424 treated specially. */
13426 {
13428 {
13431 }
13433 }
13436 {
13441 {
13459 }
13460 }
13463 {
13465 {
13472 {
13477 }
13480 }
13482 /* Return a VECTOR_CST if possible. */
13484 {
13490 tree val;
13496 }
13504 }
13506 #ifdef ENABLE_FOLD_CHECKING
13507 #undef fold
13514 /* When --enable-checking=fold, compute a digest of expr before
13515 and after actual fold call to see if fold did not accidentally
13516 change original expr. */
13518 tree
13520 {
13521 tree ret;
13541 }
13543 void
13545 {
13556 }
13558 static void
13560 {
13562 }
13564 static void
13567 {
13573 recursive_label:
13583 {
13584 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13592 }
13600 {
13601 /* Allow these fields to be modified. */
13602 tree tmp;
13613 {
13616 }
13617 }
13619 {
13620 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13621 that and change builtins.cc etc. instead - see PR89543. */
13627 }
13638 {
13641 {
13657 }
13661 {
13674 }
13691 {
13697 }
13700 {
13702 {
13705 }
13707 }
13718 {
13721 }
13731 }
13732 }
13734 /* Helper function for outputting the checksum of a tree T. When
13735 debugging with gdb, you can "define mynext" to be "next" followed
13736 by "call debug_fold_checksum (op0)", then just trace down till the
13737 outputs differ. */
13739 DEBUG_FUNCTION void
13741 {
13756 }
13758 #endif
13760 /* Fold a unary tree expression with code CODE of type TYPE with an
13761 operand OP0. LOC is the location of the resulting expression.
13762 Return a folded expression if successful. Otherwise, return a tree
13763 expression with code CODE of type TYPE with an operand OP0. */
13765 tree
13768 {
13769 tree tem;
13770 #ifdef ENABLE_FOLD_CHECKING
13779 #endif
13785 #ifdef ENABLE_FOLD_CHECKING
13792 #endif
13794 }
13796 /* Fold a binary tree expression with code CODE of type TYPE with
13797 operands OP0 and OP1. LOC is the location of the resulting
13798 expression. Return a folded expression if successful. Otherwise,
13799 return a tree expression with code CODE of type TYPE with operands
13800 OP0 and OP1. */
13802 tree
13805 MEM_STAT_DECL)
13806 {
13807 tree tem;
13808 #ifdef ENABLE_FOLD_CHECKING
13825 #endif
13831 #ifdef ENABLE_FOLD_CHECKING
13846 #endif
13848 }
13850 /* Fold a ternary tree expression with code CODE of type TYPE with
13851 operands OP0, OP1, and OP2. Return a folded expression if
13852 successful. Otherwise, return a tree expression with code CODE of
13853 type TYPE with operands OP0, OP1, and OP2. */
13855 tree
13858 {
13859 tree tem;
13860 #ifdef ENABLE_FOLD_CHECKING
13884 #endif
13891 #ifdef ENABLE_FOLD_CHECKING
13914 #endif
13916 }
13918 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13919 arguments in ARGARRAY, and a null static chain.
13920 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13921 of type TYPE from the given operands as constructed by build_call_array. */
13923 tree
13926 {
13927 tree tem;
13928 #ifdef ENABLE_FOLD_CHECKING
13947 #endif
13953 #ifdef ENABLE_FOLD_CHECKING
13969 #endif
13971 }
13973 /* Perform constant folding and related simplification of initializer
13974 expression EXPR. These behave identically to "fold_buildN" but ignore
13975 potential run-time traps and exceptions that fold must preserve. */
13977 #define START_FOLD_INIT \
13978 int saved_signaling_nans = flag_signaling_nans;\
13979 int saved_trapping_math = flag_trapping_math;\
13980 int saved_rounding_math = flag_rounding_math;\
13981 int saved_trapv = flag_trapv;\
13982 int saved_folding_initializer = folding_initializer;\
13983 flag_signaling_nans = 0;\
13984 flag_trapping_math = 0;\
13985 flag_rounding_math = 0;\
13986 flag_trapv = 0;\
13987 folding_initializer = 1;
13989 #define END_FOLD_INIT \
13990 flag_signaling_nans = saved_signaling_nans;\
13991 flag_trapping_math = saved_trapping_math;\
13992 flag_rounding_math = saved_rounding_math;\
13993 flag_trapv = saved_trapv;\
13994 folding_initializer = saved_folding_initializer;
13996 tree
13998 {
13999 tree result;
14000 START_FOLD_INIT;
14004 END_FOLD_INIT;
14006 }
14008 tree
14011 {
14012 tree result;
14013 START_FOLD_INIT;
14017 END_FOLD_INIT;
14019 }
14021 tree
14024 {
14025 tree result;
14026 START_FOLD_INIT;
14030 END_FOLD_INIT;
14032 }
14034 tree
14037 {
14038 tree result;
14039 START_FOLD_INIT;
14043 END_FOLD_INIT;
14045 }
14047 tree
14050 {
14051 tree result;
14052 START_FOLD_INIT;
14056 END_FOLD_INIT;
14058 }
14060 #undef START_FOLD_INIT
14061 #undef END_FOLD_INIT
14063 /* Determine if first argument is a multiple of second argument. Return 0 if
14064 it is not, or we cannot easily determined it to be.
14066 An example of the sort of thing we care about (at this point; this routine
14067 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14068 fold cases do now) is discovering that
14070 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14072 is a multiple of
14074 SAVE_EXPR (J * 8)
14076 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14078 This code also handles discovering that
14080 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14082 is a multiple of 8 so we don't have to worry about dealing with a
14083 possible remainder.
14085 Note that we *look* inside a SAVE_EXPR only to determine how it was
14086 calculated; it is not safe for fold to do much of anything else with the
14087 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14088 at run time. For example, the latter example above *cannot* be implemented
14089 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14090 evaluation time of the original SAVE_EXPR is not necessarily the same at
14091 the time the new expression is evaluated. The only optimization of this
14092 sort that would be valid is changing
14094 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14096 divided by 8 to
14098 SAVE_EXPR (I) * SAVE_EXPR (J)
14100 (where the same SAVE_EXPR (J) is used in the original and the
14101 transformed version).
14103 NOWRAP specifies whether all outer operations in TYPE should
14104 be considered not wrapping. Any type conversion within TOP acts
14105 as a barrier and we will fall back to NOWRAP being false.
14106 NOWRAP is mostly used to treat expressions in TYPE_SIZE and friends
14107 as not wrapping even though they are generally using unsigned arithmetic. */
14109 int
14111 {
14122 {
14124 /* Bitwise and provides a power of two multiple. If the mask is
14125 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14132 /* If the multiplication can wrap we cannot recurse further unless
14133 the bottom is a power of two which is where wrapping does not
14134 matter. */
14140 {
14146 {
14149 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14151 {
14155 {
14158 }
14159 }
14161 }
14162 }
14167 /* Handle X << CST as X * (1 << CST) and only process the constant. */
14169 {
14172 {
14173 wide_int mul_op
14177 nowrap);
14178 }
14179 }
14184 /* If the addition or subtraction can wrap we cannot recurse further
14185 unless bottom is a power of two which is where wrapping does not
14186 matter. */
14192 /* Handle cases like op0 + 0xfffffffd as op0 - 3 if the expression has
14193 unsigned type. For example, (X / 3) + 0xfffffffd is multiple of 3,
14194 but 0xfffffffd is not. */
14197 && nowrap
14202 /* It is impossible to prove if op0 +- op1 is multiple of bottom
14203 precisely, so be conservative here checking if both op0 and op1
14204 are multiple of bottom. Note we check the second operand first
14205 since it's usually simpler. */
14209 CASE_CONVERT:
14210 /* Can't handle conversions from non-integral or wider integral type. */
14215 /* NOWRAP only extends to operations in the outermost type so
14216 make sure to strip it off here. */
14231 SIGNED);
14237 {
14240 /* Check for special cases to see if top is defined as multiple
14241 of bottom:
14243 top = (X & ~(bottom - 1) ; bottom is power of 2
14245 or
14247 Y = X % bottom
14248 top = X - Y. */
14267 }
14269 /* fall through */
14277 }
14278 }
14280 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14281 This function returns true for integer expressions, and returns
14282 false if uncertain. */
14284 bool
14286 {
14291 {
14314 {
14315 CASE_CFN_FABS:
14316 CASE_CFN_FABS_FN:
14318 CASE_CFN_FMAX:
14319 CASE_CFN_FMAX_FN:
14320 CASE_CFN_FMIN:
14321 CASE_CFN_FMIN_FN:
14326 }
14330 }
14331 }
14333 /* Return true if expression X evaluates to an infinity.
14334 This function returns false for integer expressions. */
14336 bool
14338 {
14342 {
14355 }
14356 }
14358 /* Return true if expression X could evaluate to an infinity.
14359 This function returns false for integer expressions, and returns
14360 true if uncertain. */
14362 bool
14364 {
14368 {
14381 }
14382 }
14384 /* Return true if expression X evaluates to a signaling NaN.
14385 This function returns false for integer expressions. */
14387 bool
14389 {
14393 {
14404 }
14405 }
14407 /* Return true if expression X could evaluate to a signaling NaN.
14408 This function returns false for integer expressions, and returns
14409 true if uncertain. */
14411 bool
14413 {
14417 {
14437 {
14438 CASE_CFN_FABS:
14439 CASE_CFN_FABS_FN:
14441 CASE_CFN_FMAX:
14442 CASE_CFN_FMAX_FN:
14443 CASE_CFN_FMIN:
14444 CASE_CFN_FMIN_FN:
14449 }
14452 }
14453 }
14455 /* Return true if expression X evaluates to a NaN.
14456 This function returns false for integer expressions. */
14458 bool
14460 {
14464 {
14475 }
14476 }
14478 /* Return true if expression X could evaluate to a NaN.
14479 This function returns false for integer expressions, and returns
14480 true if uncertain. */
14482 bool
14484 {
14488 {
14513 {
14514 CASE_CFN_FABS:
14515 CASE_CFN_FABS_FN:
14517 CASE_CFN_FMAX:
14518 CASE_CFN_FMAX_FN:
14519 CASE_CFN_FMIN:
14520 CASE_CFN_FMIN_FN:
14525 }
14528 }
14529 }
14531 /* Return true if expression X could evaluate to -0.0.
14532 This function returns true if uncertain. */
14534 bool
14536 {
14540 {
14555 {
14556 CASE_CFN_FABS:
14557 CASE_CFN_FABS_FN:
14561 }
14564 }
14565 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14566 * but currently those predicates require tree and not const_tree. */
14568 }
14570 #define tree_expr_nonnegative_warnv_p(X, Y) \
14573 #define RECURSE(X) \
14574 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14576 /* Return true if CODE or TYPE is known to be non-negative. */
14578 static bool
14580 {
14583 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14584 have a signed:1 type (where the value is -1 and 0). */
14587 }
14589 /* Return true if (CODE OP0) is known to be non-negative. If the return
14590 value is based on the assumption that signed overflow is undefined,
14591 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14592 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14594 bool
14597 {
14602 {
14604 /* We can't return 1 if flag_wrapv is set because
14605 ABS_EXPR<INT_MIN> = INT_MIN. */
14609 {
14612 }
14620 CASE_CONVERT:
14621 {
14626 {
14630 {
14634 }
14635 }
14637 {
14643 }
14644 }
14649 }
14651 /* We don't know sign of `t', so be conservative and return false. */
14653 }
14655 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14656 value is based on the assumption that signed overflow is undefined,
14657 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14658 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14660 bool
14664 {
14669 {
14675 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14676 both unsigned and at least 2 bits shorter than the result. */
14680 {
14685 {
14689 }
14690 }
14695 {
14696 /* x * x is always non-negative for floating point x
14697 or without overflow. */
14700 {
14705 }
14706 }
14708 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14709 both unsigned and their total bits is shorter than the result. */
14713 {
14732 {
14742 }
14743 }
14750 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14751 things. */
14776 }
14778 /* We don't know sign of `t', so be conservative and return false. */
14780 }
14782 /* Return true if T is known to be non-negative. If the return
14783 value is based on the assumption that signed overflow is undefined,
14784 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14785 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14787 bool
14789 {
14794 {
14808 /* Limit the depth of recursion to avoid quadratic behavior.
14809 This is expected to catch almost all occurrences in practice.
14810 If this code misses important cases that unbounded recursion
14811 would not, passes that need this information could be revised
14812 to provide it through dataflow propagation. */
14820 }
14821 }
14823 /* Return true if T is known to be non-negative. If the return
14824 value is based on the assumption that signed overflow is undefined,
14825 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14826 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14828 bool
14831 {
14833 {
14834 CASE_CFN_ACOS:
14835 CASE_CFN_ACOS_FN:
14836 CASE_CFN_ACOSH:
14837 CASE_CFN_ACOSH_FN:
14838 CASE_CFN_CABS:
14839 CASE_CFN_CABS_FN:
14840 CASE_CFN_COSH:
14841 CASE_CFN_COSH_FN:
14842 CASE_CFN_ERFC:
14843 CASE_CFN_ERFC_FN:
14844 CASE_CFN_EXP:
14845 CASE_CFN_EXP_FN:
14846 CASE_CFN_EXP10:
14847 CASE_CFN_EXP2:
14848 CASE_CFN_EXP2_FN:
14849 CASE_CFN_FABS:
14850 CASE_CFN_FABS_FN:
14851 CASE_CFN_FDIM:
14852 CASE_CFN_FDIM_FN:
14853 CASE_CFN_HYPOT:
14854 CASE_CFN_HYPOT_FN:
14855 CASE_CFN_POW10:
14856 CASE_CFN_FFS:
14857 CASE_CFN_PARITY:
14858 CASE_CFN_POPCOUNT:
14859 CASE_CFN_CLZ:
14860 CASE_CFN_CLRSB:
14865 /* Always true. */
14868 CASE_CFN_SQRT:
14869 CASE_CFN_SQRT_FN:
14870 /* sqrt(-0.0) is -0.0. */
14875 CASE_CFN_ASINH:
14876 CASE_CFN_ASINH_FN:
14877 CASE_CFN_ATAN:
14878 CASE_CFN_ATAN_FN:
14879 CASE_CFN_ATANH:
14880 CASE_CFN_ATANH_FN:
14881 CASE_CFN_CBRT:
14882 CASE_CFN_CBRT_FN:
14883 CASE_CFN_CEIL:
14884 CASE_CFN_CEIL_FN:
14885 CASE_CFN_ERF:
14886 CASE_CFN_ERF_FN:
14887 CASE_CFN_EXPM1:
14888 CASE_CFN_EXPM1_FN:
14889 CASE_CFN_FLOOR:
14890 CASE_CFN_FLOOR_FN:
14891 CASE_CFN_FMOD:
14892 CASE_CFN_FMOD_FN:
14893 CASE_CFN_FREXP:
14894 CASE_CFN_FREXP_FN:
14895 CASE_CFN_ICEIL:
14896 CASE_CFN_IFLOOR:
14897 CASE_CFN_IRINT:
14898 CASE_CFN_IROUND:
14899 CASE_CFN_LCEIL:
14900 CASE_CFN_LDEXP:
14901 CASE_CFN_LFLOOR:
14902 CASE_CFN_LLCEIL:
14903 CASE_CFN_LLFLOOR:
14904 CASE_CFN_LLRINT:
14905 CASE_CFN_LLRINT_FN:
14906 CASE_CFN_LLROUND:
14907 CASE_CFN_LLROUND_FN:
14908 CASE_CFN_LRINT:
14909 CASE_CFN_LRINT_FN:
14910 CASE_CFN_LROUND:
14911 CASE_CFN_LROUND_FN:
14912 CASE_CFN_MODF:
14913 CASE_CFN_MODF_FN:
14914 CASE_CFN_NEARBYINT:
14915 CASE_CFN_NEARBYINT_FN:
14916 CASE_CFN_RINT:
14917 CASE_CFN_RINT_FN:
14918 CASE_CFN_ROUND:
14919 CASE_CFN_ROUND_FN:
14920 CASE_CFN_ROUNDEVEN:
14921 CASE_CFN_ROUNDEVEN_FN:
14922 CASE_CFN_SCALB:
14923 CASE_CFN_SCALBLN:
14924 CASE_CFN_SCALBLN_FN:
14925 CASE_CFN_SCALBN:
14926 CASE_CFN_SCALBN_FN:
14927 CASE_CFN_SIGNBIT:
14928 CASE_CFN_SIGNIFICAND:
14929 CASE_CFN_SINH:
14930 CASE_CFN_SINH_FN:
14931 CASE_CFN_TANH:
14932 CASE_CFN_TANH_FN:
14933 CASE_CFN_TRUNC:
14934 CASE_CFN_TRUNC_FN:
14935 /* True if the 1st argument is nonnegative. */
14938 CASE_CFN_FMAX:
14939 CASE_CFN_FMAX_FN:
14940 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14941 things. In the presence of sNaNs, we're only guaranteed to be
14942 non-negative if both operands are non-negative. In the presence
14943 of qNaNs, we're non-negative if either operand is non-negative
14944 and can't be a qNaN, or if both operands are non-negative. */
14953 CASE_CFN_FMIN:
14954 CASE_CFN_FMIN_FN:
14955 /* True if the 1st AND 2nd arguments are nonnegative. */
14958 CASE_CFN_COPYSIGN:
14959 CASE_CFN_COPYSIGN_FN:
14960 /* True if the 2nd argument is nonnegative. */
14963 CASE_CFN_POWI:
14964 /* True if the 1st argument is nonnegative or the second
14965 argument is an even integer. */
14971 CASE_CFN_POW:
14972 CASE_CFN_POW_FN:
14973 /* True if the 1st argument is nonnegative or the second
14974 argument is an even integer valued real. */
14976 {
14977 REAL_VALUE_TYPE c;
14978 HOST_WIDE_INT n;
14983 {
14984 REAL_VALUE_TYPE cint;
14988 }
14989 }
14994 }
14996 }
14998 /* Return true if T is known to be non-negative. If the return
14999 value is based on the assumption that signed overflow is undefined,
15000 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15001 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15003 static bool
15005 {
15011 {
15013 {
15017 /* If the initializer is non-void, then it's a normal expression
15018 that will be assigned to the slot. */
15022 /* Otherwise, the initializer sets the slot in some way. One common
15023 way is an assignment statement at the end of the initializer. */
15025 {
15033 else
15035 }
15041 }
15044 {
15050 arg0,
15051 arg1,
15053 }
15066 }
15067 }
15069 #undef RECURSE
15070 #undef tree_expr_nonnegative_warnv_p
15072 /* Return true if T is known to be non-negative. If the return
15073 value is based on the assumption that signed overflow is undefined,
15074 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15075 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15077 bool
15079 {
15086 {
15108 }
15111 {
15136 }
15137 }
15139 /* Return true if `t' is known to be non-negative. Handle warnings
15140 about undefined signed overflow. */
15142 bool
15144 {
15151 "determining that expression is always "
15153 WARN_STRICT_OVERFLOW_MISC);
15155 }
15158 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15159 For floating point we further ensure that T is not denormal.
15160 Similar logic is present in nonzero_address in rtlanal.h.
15162 If the return value is based on the assumption that signed overflow
15163 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15164 change *STRICT_OVERFLOW_P. */
15166 bool
15169 {
15171 {
15174 strict_overflow_p);
15177 {
15183 strict_overflow_p));
15184 }
15189 strict_overflow_p);
15193 }
15196 }
15198 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15199 For floating point we further ensure that T is not denormal.
15200 Similar logic is present in nonzero_address in rtlanal.h.
15202 If the return value is based on the assumption that signed overflow
15203 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15204 change *STRICT_OVERFLOW_P. */
15206 bool
15208 tree type,
15209 tree op0,
15211 {
15214 {
15218 {
15219 /* With the presence of negative values it is hard
15220 to say something. */
15227 /* One of operands must be positive and the other non-negative. */
15228 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15229 overflows, on a twos-complement machine the sum of two
15230 nonnegative numbers can never be zero. */
15232 strict_overflow_p)
15234 strict_overflow_p));
15235 }
15240 {
15242 strict_overflow_p)
15244 strict_overflow_p))
15245 {
15248 }
15249 }
15258 {
15261 }
15268 {
15272 /* When both operands are nonzero, then MAX must be too. */
15274 strict_overflow_p))
15277 /* MAX where operand 0 is positive is positive. */
15279 strict_overflow_p);
15280 }
15281 /* MAX where operand 1 is positive is positive. */
15286 {
15290 }
15295 strict_overflow_p)
15297 strict_overflow_p));
15301 }
15304 }
15306 /* Return true when T is an address and is known to be nonzero.
15307 For floating point we further ensure that T is not denormal.
15308 Similar logic is present in nonzero_address in rtlanal.h.
15310 If the return value is based on the assumption that signed overflow
15311 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15312 change *STRICT_OVERFLOW_P. */
15314 bool
15316 {
15319 {
15324 {
15336 /* For objects in symbol table check if we know they are non-zero.
15337 Don't do anything for variables and functions before symtab is built;
15338 it is quite possible that they will be declared weak later. */
15343 /* Constants are never weak. */
15348 }
15356 {
15360 }
15370 }
15372 }
15374 #define integer_valued_real_p(X) \
15377 #define RECURSE(X) \
15378 ((integer_valued_real_p) (X, depth + 1))
15380 /* Return true if the floating point result of (CODE OP0) has an
15381 integer value. We also allow +Inf, -Inf and NaN to be considered
15382 integer values. Return false for signaling NaN.
15384 DEPTH is the current nesting depth of the query. */
15386 bool
15388 {
15390 {
15397 CASE_CONVERT:
15398 {
15405 }
15409 }
15411 }
15413 /* Return true if the floating point result of (CODE OP0 OP1) has an
15414 integer value. We also allow +Inf, -Inf and NaN to be considered
15415 integer values. Return false for signaling NaN.
15417 DEPTH is the current nesting depth of the query. */
15419 bool
15421 {
15423 {
15433 }
15435 }
15437 /* Return true if the floating point result of calling FNDECL with arguments
15438 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15439 considered integer values. Return false for signaling NaN. If FNDECL
15440 takes fewer than 2 arguments, the remaining ARGn are null.
15442 DEPTH is the current nesting depth of the query. */
15444 bool
15446 {
15448 {
15449 CASE_CFN_CEIL:
15450 CASE_CFN_CEIL_FN:
15451 CASE_CFN_FLOOR:
15452 CASE_CFN_FLOOR_FN:
15453 CASE_CFN_NEARBYINT:
15454 CASE_CFN_NEARBYINT_FN:
15455 CASE_CFN_RINT:
15456 CASE_CFN_RINT_FN:
15457 CASE_CFN_ROUND:
15458 CASE_CFN_ROUND_FN:
15459 CASE_CFN_ROUNDEVEN:
15460 CASE_CFN_ROUNDEVEN_FN:
15461 CASE_CFN_TRUNC:
15462 CASE_CFN_TRUNC_FN:
15465 CASE_CFN_FMIN:
15466 CASE_CFN_FMIN_FN:
15467 CASE_CFN_FMAX:
15468 CASE_CFN_FMAX_FN:
15473 }
15475 }
15477 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15478 has an integer value. We also allow +Inf, -Inf and NaN to be
15479 considered integer values. Return false for signaling NaN.
15481 DEPTH is the current nesting depth of the query. */
15483 bool
15485 {
15487 {
15495 /* Limit the depth of recursion to avoid quadratic behavior.
15496 This is expected to catch almost all occurrences in practice.
15497 If this code misses important cases that unbounded recursion
15498 would not, passes that need this information could be revised
15499 to provide it through dataflow propagation. */
15503 depth));
15507 }
15509 }
15511 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15512 has an integer value. We also allow +Inf, -Inf and NaN to be
15513 considered integer values. Return false for signaling NaN.
15515 DEPTH is the current nesting depth of the query. */
15517 static bool
15519 {
15521 {
15532 }
15534 }
15536 #undef RECURSE
15537 #undef integer_valued_real_p
15539 /* Return true if the floating point expression T has an integer value.
15540 We also allow +Inf, -Inf and NaN to be considered integer values.
15541 Return false for signaling NaN.
15543 DEPTH is the current nesting depth of the query. */
15545 bool
15547 {
15555 {
15571 }
15574 {
15580 {
15589 }
15593 }
15594 }
15596 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15597 attempt to fold the expression to a constant without modifying TYPE,
15598 OP0 or OP1.
15600 If the expression could be simplified to a constant, then return
15601 the constant. If the expression would not be simplified to a
15602 constant, then return NULL_TREE. */
15604 tree
15606 {
15609 }
15611 /* Given the components of a unary expression CODE, TYPE and OP0,
15612 attempt to fold the expression to a constant without modifying
15613 TYPE or OP0.
15615 If the expression could be simplified to a constant, then return
15616 the constant. If the expression would not be simplified to a
15617 constant, then return NULL_TREE. */
15619 tree
15621 {
15624 }
15626 /* If EXP represents referencing an element in a constant string
15627 (either via pointer arithmetic or array indexing), return the
15628 tree representing the value accessed, otherwise return NULL. */
15630 tree
15632 {
15636 {
15638 tree index;
15639 tree string;
15644 else
15645 {
15649 /* Optimize the special-case of a zero lower bound.
15651 We convert the low_bound to sizetype to avoid some problems
15652 with constant folding. (E.g. suppose the lower bound is 1,
15653 and its mode is QI. Without the conversion,l (ARRAY
15654 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15655 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15661 }
15663 scalar_int_mode char_mode;
15675 }
15677 }
15679 /* Folds a read from vector element at IDX of vector ARG. */
15681 tree
15683 {
15688 {
15692 {
15699 }
15700 }
15702 }
15704 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15705 an integer constant, real, or fixed-point constant.
15707 TYPE is the type of the result. */
15709 static tree
15711 {
15715 {
15721 {
15722 FIXED_VALUE_TYPE f;
15727 /* Propagate overflow flags. */
15731 }
15735 {
15742 }
15745 }
15748 }
15750 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15751 an integer constant or real constant.
15753 TYPE is the type of the result. */
15755 tree
15757 {
15761 {
15763 {
15764 /* If the value is unsigned or non-negative, then the absolute value
15765 is the same as the ordinary value. */
15769 ;
15771 /* If the value is negative, then the absolute value is
15772 its negation. */
15773 else
15776 /* Force to the destination type, set TREE_OVERFLOW for signed
15777 TYPE only. */
15779 }
15785 else
15791 }
15794 }
15796 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15797 constant. TYPE is the type of the result. */
15799 static tree
15801 {
15805 }
15807 /* Given CODE, a relational operator, the target type, TYPE and two
15808 constant operands OP0 and OP1, return the result of the
15809 relational operation. If the result is not a compile time
15810 constant, then return NULL_TREE. */
15812 static tree
15814 {
15817 /* From here on, the only cases we handle are when the result is
15818 known to be a constant. */
15821 {
15825 /* Handle the cases where either operand is a NaN. */
15827 {
15829 {
15857 }
15860 }
15863 }
15866 {
15870 }
15872 /* Handle equality/inequality of complex constants. */
15874 {
15885 else
15887 }
15890 {
15892 {
15893 /* Have vector comparison with scalar boolean result. */
15901 {
15909 }
15911 }
15912 tree_vector_builder elts;
15917 {
15930 }
15933 }
15935 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15937 To compute GT, swap the arguments and do LT.
15938 To compute GE, do LT and invert the result.
15939 To compute LE, swap the arguments, do LT and invert the result.
15940 To compute NE, do EQ and invert the result.
15942 Therefore, the code below must handle only EQ and LT. */
15945 {
15948 }
15950 /* Note that it is safe to invert for real values here because we
15951 have already handled the one case that it matters. */
15955 {
15958 }
15960 /* Compute a result for LT or EQ if args permit;
15961 Otherwise return T. */
15963 {
15966 else
15968 }
15969 else
15975 }
15977 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15978 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15979 itself. */
15981 tree
15983 {
15984 /* If the expression does not have side effects then we don't have to wrap
15985 it with a cleanup point expression. */
15989 /* If the expression is a return, check to see if the expression inside the
15990 return has no side effects or the right hand side of the modify expression
15991 inside the return. If either don't have side effects set we don't need to
15992 wrap the expression in a cleanup point expression. Note we don't check the
15993 left hand side of the modify because it should always be a return decl. */
15995 {
16002 }
16005 }
16007 /* Given a pointer value OP0 and a type TYPE, return a simplified version
16008 of an indirection through OP0, or NULL_TREE if no simplification is
16009 possible. */
16011 tree
16013 {
16015 tree subtype;
16016 poly_uint64 const_op01;
16025 {
16029 /* *&CONST_DECL -> to the value of the const decl. */
16032 /* *&p => p; make sure to handle *&"str"[cst] here. */
16034 {
16038 else
16040 }
16041 /* *(foo *)&fooarray => fooarray[0] */
16044 && (!in_gimple_form
16046 {
16056 }
16057 /* *(foo *)&complexfoo => __real__ complexfoo */
16061 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
16064 {
16068 index);
16069 }
16070 }
16074 {
16080 {
16081 tree op00type;
16085 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
16088 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
16089 but we want to treat offsets with MSB set as negative.
16090 For the code below negative offsets are invalid and
16091 TYPE_SIZE of the element is something unsigned, so
16092 check whether op01 fits into poly_int64, which implies
16093 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
16094 then just use poly_uint64 because we want to treat the
16095 value as unsigned. */
16097 {
16099 poly_uint64 max_offset
16103 {
16108 }
16109 }
16110 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
16113 {
16115 const_op01))
16117 }
16118 /* ((foo *)&fooarray)[1] => fooarray[1] */
16121 {
16130 {
16135 }
16136 }
16137 }
16138 }
16140 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16143 && (!in_gimple_form
16145 {
16146 tree type_domain;
16156 NULL_TREE);
16157 }
16160 }
16162 /* Builds an expression for an indirection through T, simplifying some
16163 cases. */
16165 tree
16167 {
16175 }
16177 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16179 tree
16181 {
16186 else
16188 }
16190 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16191 whose result is ignored. The type of the returned tree need not be
16192 the same as the original expression. */
16194 tree
16196 {
16202 {
16213 else
16219 {
16235 }
16240 }
16241 }
16243 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16245 tree
16247 {
16253 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16254 have to do anything. Only do this when we are not given a const,
16255 because in that case, this check is more expensive than just
16256 doing it. */
16258 {
16263 }
16265 /* If divisor is a power of two, simplify this to bit manipulation. */
16267 {
16269 {
16283 }
16284 else
16285 {
16286 tree t;
16292 }
16293 }
16294 else
16295 {
16300 }
16303 }
16305 /* Likewise, but round down. */
16307 tree
16309 {
16316 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16317 have to do anything. Only do this when we are not given a const,
16318 because in that case, this check is more expensive than just
16319 doing it. */
16321 {
16326 }
16328 /* If divisor is a power of two, simplify this to bit manipulation. */
16330 {
16331 tree t;
16335 }
16336 else
16337 {
16342 }
16345 }
16347 /* Returns the pointer to the base of the object addressed by EXP and
16348 extracts the information about the offset of the access, storing it
16349 to PBITPOS and POFFSET. */
16351 static tree
16354 {
16355 tree core;
16356 machine_mode mode;
16358 poly_int64 bitsize;
16367 {
16372 }
16374 {
16380 {
16381 poly_offset_int tem
16387 }
16388 }
16389 else
16390 {
16394 }
16397 }
16399 /* Returns true if addresses of E1 and E2 differ by a constant, false
16400 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16402 bool
16404 {
16419 {
16429 }
16431 {
16432 /* If only one of the offsets is non-constant, the difference cannot
16433 be a constant. */
16435 }
16436 else
16441 }
16443 /* Return OFF converted to a pointer offset type suitable as offset for
16444 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16445 tree
16447 {
16451 }
16453 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16454 tree
16456 {
16459 }
16461 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16462 tree
16464 {
16467 }
16469 /* Return a pointer to a NUL-terminated string containing the sequence
16470 of bytes corresponding to the representation of the object referred to
16471 by SRC (or a subsequence of such bytes within it if SRC is a reference
16472 to an initialized constant array plus some constant offset).
16473 Set *STRSIZE the number of bytes in the constant sequence including
16474 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16475 where A is the array that stores the constant sequence that SRC points
16476 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16477 need not point to a string or even an array of characters but may point
16478 to an object of any type. */
16482 {
16483 /* The offset into the array A storing the string, and A's byte size. */
16484 tree offset_node;
16485 tree mem_size;
16492 else
16499 {
16502 else
16504 }
16509 /* ARRAY_SIZE is the byte size of the array the constant sequence
16510 is stored in and equal to sizeof A. INIT_BYTES is the number
16511 of bytes in the constant sequence used to initialize the array,
16512 including any embedded NULs as well as the terminating NUL (for
16513 strings), but not including any trailing zeros/NULs past
16514 the terminating one appended implicitly to a string literal to
16515 zero out the remainder of the array it's stored in. For example,
16516 given:
16517 const char a[7] = "abc\0d";
16518 n = strlen (a + 1);
16519 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16520 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16521 is equal to strlen (A) + 1. */
16526 /* Ideally this would turn into a gcc_checking_assert over time. */
16534 {
16535 /* Compute and store the number of characters from the beginning
16536 of the substring at OFFSET to the end, including the terminating
16537 nul. Offsets past the initial length refer to null strings. */
16540 else
16542 }
16543 else
16544 {
16546 /* Support only properly NUL-terminated single byte strings. */
16551 }
16554 }
16556 /* Return a pointer to a NUL-terminated string corresponding to
16557 the expression STR referencing a constant string, possibly
16558 involving a constant offset. Return null if STR either doesn't
16559 reference a constant string or if it involves a nonconstant
16560 offset. */
16564 {
16566 }
16568 /* Given a tree T, compute which bits in T may be nonzero. */
16570 wide_int
16572 {
16574 {
16592 CASE_CONVERT:
16598 {
16603 }
16607 {
16615 }
16619 {
16627 }
16631 }
16634 }
16636 /* Helper function for address compare simplifications in match.pd.
16637 OP0 and OP1 are ADDR_EXPR operands being compared by CODE.
16638 TYPE is the type of comparison operands.
16639 BASE0, BASE1, OFF0 and OFF1 are set by the function.
16640 GENERIC is true if GENERIC folding and false for GIMPLE folding.
16641 Returns 0 if OP0 is known to be unequal to OP1 regardless of OFF{0,1},
16642 1 if bases are known to be equal and OP0 cmp OP1 depends on OFF0 cmp OFF1,
16643 and 2 if unknown. */
16645 int
16649 {
16659 {
16662 }
16664 {
16667 }
16672 /* Punt in GENERIC on variables with value expressions;
16673 the value expressions might point to fields/elements
16674 of other vars etc. */
16680 {
16684 }
16692 /* Assume different STRING_CSTs with the same content will be
16693 merged. */
16702 {
16705 /* If the offsets are equal we can ignore overflow. */
16708 /* Or if we compare using pointers to decls or strings. */
16713 }
16719 /* At this point we know (or assume) the two pointers point at
16720 different objects. */
16724 /* Punt on non-zero offsets from functions. */
16728 /* Or if the bases are neither decls nor string literals. */
16733 /* For initializers, assume addresses of different functions are
16734 different. */
16740 /* Compute whether one address points to the start of one
16741 object and another one to the end of another one. */
16744 {
16747 else
16749 }
16752 else
16753 {
16757 else
16759 }
16761 {
16764 else
16766 }
16769 else
16770 {
16774 else
16776 }
16778 {
16779 /* If one offset is pointing (or could be) to the beginning of one
16780 object and the other is pointing to one past the last byte of the
16781 other object, punt. */
16786 /* If both offsets are the same, there are some cases we know that are
16787 ok. Either if we know they aren't zero, or if we know both sizes
16788 are no zero. */
16794 }
16796 /* At this point, equal is 2 if either one or both pointers are out of
16797 bounds of their object, or one points to start of its object and the
16798 other points to end of its object. This is unspecified behavior
16799 e.g. in C++. Otherwise equal is 0. */
16803 /* When both pointers point to string literals, even when equal is 0,
16804 due to tail merging of string literals the pointers might be the same. */
16806 {
16813 /* If the bytes in the string literals starting at the pointers
16814 differ, the pointers need to be different. */
16819 {
16824 /* If even the bytes in the string literal before the
16825 pointers are the same, the string literals could be
16826 tail merged. */
16828 }
16830 }
16835 /* If this is a pointer comparison, ignore for now even
16836 valid equalities where one pointer is the offset zero
16837 of one object and the other to one past end of another one. */
16841 /* Assume that string literals can't be adjacent to variables
16842 (automatic or global). */
16846 /* Assume that automatic variables can't be adjacent to global
16847 variables. */
16852 }
16854 /* Return the single non-zero element of a CONSTRUCTOR or NULL_TREE. */
16855 tree
16857 {
16866 {
16870 }
16872 }
16874 #if CHECKING_P
16878 /* Helper functions for writing tests of folding trees. */
16880 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16882 static void
16884 tree constant)
16885 {
16887 }
16889 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16890 wrapping WRAPPED_EXPR. */
16892 static void
16894 tree wrapped_expr)
16895 {
16900 }
16902 /* Verify that various arithmetic binary operations are folded
16903 correctly. */
16905 static void
16907 {
16913 /* Addition. */
16914 /* 1 <-- (0 + 1) */
16916 one);
16918 one);
16920 /* (nonlvalue)x <-- (x + 0) */
16922 x);
16924 /* Subtraction. */
16925 /* 0 <-- (x - x) */
16927 zero);
16929 x);
16931 /* Multiplication. */
16932 /* 0 <-- (x * 0) */
16934 zero);
16936 /* (nonlvalue)x <-- (x * 1) */
16938 x);
16939 }
16941 /* Verify that various binary operations on vectors are folded
16942 correctly. */
16944 static void
16946 {
16953 /* Verify equality tests that return a scalar boolean result. */
16966 }
16968 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16970 static void
16972 {
16975 /* This will be 1 if VEC_MODE isn't a vector mode. */
16982 }
16984 /* Run all of the selftests within this file. */
16986 void
16988 {
16992 }