| blob | 114258fa182b1bede268a61e073130746545da1a |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2022 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. */
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 /* Don't perform the operation if flag_signaling_nans is on
2182 and the operand is a signaling NaN. */
2187 /* With flag_rounding_math we should respect the current rounding mode
2188 unless the conversion is exact. */
2196 /* If converting an infinity or NAN to a representation that doesn't
2197 have one, set the overflow bit so that we can produce some kind of
2198 error message at the appropriate point if necessary. It's not the
2199 most user-friendly message, but it's better than nothing. */
2206 /* Regular overflow, conversion produced an infinity in a mode that
2207 can't represent them. */
2212 else
2215 }
2217 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2218 to a floating point type. */
2220 static tree
2222 {
2223 REAL_VALUE_TYPE value;
2224 tree t;
2232 }
2234 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2235 to another fixed-point type. */
2237 static tree
2239 {
2240 FIXED_VALUE_TYPE value;
2241 tree t;
2248 /* Propagate overflow flags. */
2252 }
2254 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2255 to a fixed-point type. */
2257 static tree
2259 {
2260 FIXED_VALUE_TYPE value;
2261 tree t;
2263 double_int di;
2270 else
2278 /* Propagate overflow flags. */
2282 }
2284 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2285 to a fixed-point type. */
2287 static tree
2289 {
2290 FIXED_VALUE_TYPE value;
2291 tree t;
2299 /* Propagate overflow flags. */
2303 }
2305 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2306 type TYPE. If no simplification can be done return NULL_TREE. */
2308 static tree
2310 {
2315 /* We can't widen types, since the runtime value could overflow the
2316 original type before being extended to the new type. */
2327 {
2334 }
2336 {
2338 {
2340 /* Avoid the folding if flag_rounding_math is on and the
2341 conversion is not exact. */
2343 {
2349 }
2351 }
2356 }
2358 {
2365 }
2367 {
2370 {
2373 /* We can't handle steps directly when extending, since the
2374 values need to wrap at the original precision first. */
2375 bool step_ok_p
2379 tree_vector_builder v;
2384 {
2390 }
2392 }
2393 }
2395 }
2397 /* Construct a vector of zero elements of vector type TYPE. */
2399 static tree
2401 {
2402 tree t;
2406 }
2408 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2410 bool
2412 {
2427 {
2449 }
2450 }
2452 /* Convert expression ARG to type TYPE. Used by the middle-end for
2453 simple conversions in preference to calling the front-end's convert. */
2455 tree
2457 {
2459 tree tem;
2470 {
2473 /* Handle conversions between pointers to different address spaces. */
2478 /* fall through */
2483 {
2487 }
2501 {
2505 }
2507 {
2511 }
2513 {
2517 }
2520 {
2538 }
2543 {
2547 }
2550 {
2564 }
2568 {
2577 integer_zero_node));
2579 {
2583 {
2589 }
2597 }
2601 }
2619 }
2620 fold_convert_exit:
2623 }
2624 \f
2625 /* Return false if expr can be assumed not to be an lvalue, true
2626 otherwise. */
2628 static bool
2630 {
2631 /* We only need to wrap lvalue tree codes. */
2633 {
2665 /* Assume the worst for front-end tree codes. */
2669 }
2672 }
2674 /* Return an expr equal to X but certainly not valid as an lvalue. */
2676 tree
2678 {
2679 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2680 us. */
2687 }
2688 \f
2689 /* Given a tree comparison code, return the code that is the logical inverse.
2690 It is generally not safe to do this for floating-point comparisons, except
2691 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2692 ERROR_MARK in this case. */
2694 enum tree_code
2696 {
2702 {
2733 }
2734 }
2736 /* Similar, but return the comparison that results if the operands are
2737 swapped. This is safe for floating-point. */
2739 enum tree_code
2741 {
2743 {
2769 }
2770 }
2773 /* Convert a comparison tree code from an enum tree_code representation
2774 into a compcode bit-based encoding. This function is the inverse of
2775 compcode_to_comparison. */
2777 static enum comparison_code
2779 {
2781 {
2812 }
2813 }
2815 /* Convert a compcode bit-based encoding of a comparison operator back
2816 to GCC's enum tree_code representation. This function is the
2817 inverse of comparison_to_compcode. */
2819 static enum tree_code
2821 {
2823 {
2854 }
2855 }
2857 /* Return true if COND1 tests the opposite condition of COND2. */
2859 bool
2861 {
2864 && (invert_tree_comparison
2871 }
2873 /* Return a tree for the comparison which is the combination of
2874 doing the AND or OR (depending on CODE) of the two operations LCODE
2875 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2876 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2877 if this makes the transformation invalid. */
2879 tree
2884 {
2891 {
2902 }
2905 {
2906 /* Eliminate unordered comparisons, as well as LTGT and ORD
2907 which are not used unless the mode has NaNs. */
2913 }
2915 {
2916 /* Check that the original operation and the optimized ones will trap
2917 under the same condition. */
2928 /* In a short-circuited boolean expression the LHS might be
2929 such that the RHS, if evaluated, will never trap. For
2930 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2931 if neither x nor y is NaN. (This is a mixed blessing: for
2932 example, the expression above will never trap, hence
2933 optimizing it to x < y would be invalid). */
2938 /* If the comparison was short-circuited, and only the RHS
2939 trapped, we may now generate a spurious trap. */
2944 /* If we changed the conditions that cause a trap, we lose. */
2947 }
2953 else
2954 {
2959 }
2960 }
2961 \f
2962 /* Return nonzero if two operands (typically of the same tree node)
2963 are necessarily equal. FLAGS modifies behavior as follows:
2965 If OEP_ONLY_CONST is set, only return nonzero for constants.
2966 This function tests whether the operands are indistinguishable;
2967 it does not test whether they are equal using C's == operation.
2968 The distinction is important for IEEE floating point, because
2969 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2970 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2972 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2973 even though it may hold multiple values during a function.
2974 This is because a GCC tree node guarantees that nothing else is
2975 executed between the evaluation of its "operands" (which may often
2976 be evaluated in arbitrary order). Hence if the operands themselves
2977 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2978 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2979 unset means assuming isochronic (or instantaneous) tree equivalence.
2980 Unless comparing arbitrary expression trees, such as from different
2981 statements, this flag can usually be left unset.
2983 If OEP_PURE_SAME is set, then pure functions with identical arguments
2984 are considered the same. It is used when the caller has other ways
2985 to ensure that global memory is unchanged in between.
2987 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2988 not values of expressions.
2990 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2991 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2993 If OEP_BITWISE is set, then require the values to be bitwise identical
2994 rather than simply numerically equal. Do not take advantage of things
2995 like math-related flags or undefined behavior; only return true for
2996 values that are provably bitwise identical in all circumstances.
2998 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2999 any operand with side effect. This is unnecesarily conservative in the
3000 case we know that arg0 and arg1 are in disjoint code paths (such as in
3001 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
3002 addresses with TREE_CONSTANT flag set so we know that &var == &var
3003 even if var is volatile. */
3005 bool
3008 {
3016 /* If either is ERROR_MARK, they aren't equal. */
3022 /* Similar, if either does not have a type (like a template id),
3023 they aren't equal. */
3027 /* Bitwise identity makes no sense if the values have different layouts. */
3032 /* We cannot consider pointers to different address space equal. */
3039 /* Check equality of integer constants before bailing out due to
3040 precision differences. */
3042 {
3043 /* Address of INTEGER_CST is not defined; check that we did not forget
3044 to drop the OEP_ADDRESS_OF flags. */
3047 }
3050 {
3051 /* If both types don't have the same signedness, then we can't consider
3052 them equal. We must check this before the STRIP_NOPS calls
3053 because they may change the signedness of the arguments. As pointers
3054 strictly don't have a signedness, require either two pointers or
3055 two non-pointers as well. */
3061 /* If both types don't have the same precision, then it is not safe
3062 to strip NOPs. */
3069 }
3070 #if 0
3071 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3072 sanity check once the issue is solved. */
3073 else
3074 /* Addresses of conversions and SSA_NAMEs (and many other things)
3075 are not defined. Check that we did not forget to drop the
3076 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3079 #endif
3081 /* In case both args are comparisons but with different comparison
3082 code, try to swap the comparison operands of one arg to produce
3083 a match and compare that variant. */
3087 {
3095 }
3098 {
3099 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3101 ;
3103 {
3104 /* If we are interested in comparing addresses ignore
3105 MEM_REF wrappings of the base that can appear just for
3106 TBAA reasons. */
3120 }
3121 else
3123 }
3125 /* When not checking adddresses, this is needed for conversions and for
3126 COMPONENT_REF. Might as well play it safe and always test this. */
3133 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3134 We don't care about side effects in that case because the SAVE_EXPR
3135 takes care of that for us. In all other cases, two expressions are
3136 equal if they have no side effects. If we have two identical
3137 expressions with side effects that should be treated the same due
3138 to the only side effects being identical SAVE_EXPR's, that will
3139 be detected in the recursive calls below.
3140 If we are taking an invariant address of two identical objects
3141 they are necessarily equal as well. */
3148 /* Next handle constant cases, those for which we can return 1 even
3149 if ONLY_CONST is set. */
3152 {
3165 {
3166 /* If we do not distinguish between signed and unsigned zero,
3167 consider them equal. */
3170 }
3174 {
3189 }
3193 flags)
3195 flags));
3206 flags | OEP_ADDRESS_OF
3209 /* In GIMPLE empty constructors are allowed in initializers of
3210 aggregates. */
3214 }
3216 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3217 two instances of undefined behavior will give identical results. */
3221 /* Define macros to test an operand from arg0 and arg1 for equality and a
3222 variant that allows null and views null as being different from any
3223 non-null value. In the latter case, if either is null, the both
3224 must be; otherwise, do the normal comparison. */
3225 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3226 TREE_OPERAND (arg1, N), flags)
3228 #define OP_SAME_WITH_NULL(N) \
3229 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3230 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3233 {
3235 /* Two conversions are equal only if signedness and modes match. */
3237 {
3238 CASE_CONVERT:
3246 }
3256 /* For commutative ops, allow the other order. */
3264 /* If either of the pointer (or reference) expressions we are
3265 dereferencing contain a side effect, these cannot be equal,
3266 but their addresses can be. */
3273 {
3276 {
3280 /* Verify that the access types are compatible. */
3284 }
3289 /* Require the same offset. */
3295 /* Fallthru. */
3303 {
3304 /* Require equal access sizes */
3310 flags)))
3312 /* Verify that access happens in similar types. */
3315 /* Verify that accesses are TBAA compatible. */
3324 /* Verify that alignment is compatible. */
3328 }
3331 /* TARGET_MEM_REF require equal extra operands. */
3342 /* Compare the array index by value if it is constant first as we
3343 may have different types but same value here. */
3349 /* Compare low bound and element size as with OEP_ADDRESS_OF
3350 we have to account for the offset of the ref. */
3355 array_ref_low_bound
3359 array_ref_element_size
3361 flags))));
3364 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3365 may be NULL when we're called to compare MEM_EXPRs. */
3368 {
3371 /* Most of time we only need to compare FIELD_DECLs for equality.
3372 However when determining address look into actual offsets.
3373 These may match for unions and unshared record types. */
3376 {
3379 {
3383 /* Non-FIELD_DECL operands can appear in C++ templates. */
3390 flags))
3392 }
3393 else
3395 }
3396 }
3407 }
3411 {
3413 /* Be sure we pass right ADDRESS_OF flag. */
3430 /* The multiplcation operands are commutative. */
3431 /* FALLTHRU */
3439 /* Otherwise take into account this is a commutative operation. */
3452 /* BIT_INSERT_EXPR has an implict operand as the type precision
3453 of op1. Need to check to make sure they are the same. */
3459 /* FALLTHRU */
3484 /* Virtual table reference. */
3496 {
3501 }
3506 }
3510 {
3514 /* If not both CALL_EXPRs are either internal or normal function
3515 functions, then they are not equal. */
3518 {
3519 /* If the CALL_EXPRs call different internal functions, then they
3520 are not equal. */
3523 }
3524 else
3525 {
3526 /* If the CALL_EXPRs call different functions, then they are not
3527 equal. */
3529 flags))
3531 }
3533 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3534 {
3538 else
3542 }
3544 /* Now see if all the arguments are the same. */
3545 {
3556 /* If we get here and both argument lists are exhausted
3557 then the CALL_EXPRs are equal. */
3559 }
3562 }
3565 /* Consider __builtin_sqrt equal to sqrt. */
3575 {
3576 /* Consider decls with the same name equal. The caller needs
3577 to make sure they refer to the same entity (such as a function
3578 formal parameter). */
3584 }
3589 {
3593 /* In GIMPLE constructors are used only to build vectors from
3594 elements. Individual elements in the constructor must be
3595 indexed in increasing order and form an initial sequence.
3597 We make no effort to compare constructors in generic.
3598 (see sem_variable::equals in ipa-icf which can do so for
3599 constants). */
3604 /* Be sure that vectors constructed have the same representation.
3605 We only tested element precision and modes to match.
3606 Vectors may be BLKmode and thus also check that the number of
3607 parts match. */
3620 {
3625 /* In GIMPLE the indexes can be either NULL or matching i.
3626 Double check this so we won't get false
3627 positives for GENERIC. */
3635 }
3637 }
3640 {
3641 /* Compare the STATEMENT_LISTs. */
3647 {
3648 /* The lists don't have the same number of statements. */
3654 flags & (OEP_LEXICOGRAPHIC
3657 }
3658 }
3663 {
3674 }
3678 }
3680 #undef OP_SAME
3681 #undef OP_SAME_WITH_NULL
3682 }
3684 /* Generate a hash value for an expression. This can be used iteratively
3685 by passing a previous result as the HSTATE argument. */
3687 void
3690 {
3696 {
3699 }
3709 {
3710 /* Alas, constants aren't shared, so we can't rely on pointer
3711 identity. */
3721 {
3725 else
3729 }
3731 {
3735 }
3745 {
3752 }
3754 /* We can just compare by pointer. */
3758 /* The node itself doesn't matter. */
3762 /* Ignore. */
3765 /* A list of expressions, for a CALL_EXPR or as the elements of a
3766 VECTOR_CST. */
3771 {
3777 {
3778 /* In GIMPLE the indexes can be either NULL or matching i. */
3783 }
3785 }
3787 {
3788 tree_stmt_iterator i;
3793 }
3802 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3803 Otherwise nodes that compare equal according to operand_equal_p might
3804 get different hash codes. However, don't do this for machine specific
3805 or front end builtins, since the function code is overloaded in those
3806 cases. */
3809 {
3812 }
3813 /* FALL THROUGH */
3816 {
3820 }
3824 {
3825 /* DECL's have a unique ID */
3827 }
3829 {
3830 /* For comparisons that can be swapped, use the lower
3831 tree code. */
3838 }
3840 {
3841 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3842 operand_equal_p. */
3846 /* Don't hash the type, that can lead to having nodes which
3847 compare equal according to operand_equal_p, but which
3848 have different hash codes. Make sure to include signedness
3849 in the hash computation. */
3852 }
3853 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3861 /* Don't ICE on FE specific trees, or their arguments etc.
3862 during operand_equal_p hash verification. */
3865 else
3866 {
3872 {
3888 {
3895 }
3909 {
3910 /* The multiplication operands are commutative. */
3917 }
3925 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3926 Usually different TARGET_EXPRs just should use
3927 different temporaries in their slots. */
3932 /* Virtual table reference. */
3940 {
3942 /* We compute mangled names only when free_lang_data is run.
3943 In that case we can hash precisely. */
3946 hstate.add_object
3947 (IDENTIFIER_HASH_VALUE
3949 }
3953 }
3955 /* Don't hash the type, that can lead to having nodes which
3956 compare equal according to operand_equal_p, but which
3957 have different hash codes. */
3959 {
3960 /* Make sure to include signness in the hash computation. */
3963 }
3966 {
3967 /* It's a commutative expression. We want to hash it the same
3968 however it appears. We do this by first hashing both operands
3969 and then rehashing based on the order of their independent
3970 hashes. */
3975 }
3976 else
3980 }
3982 }
3983 }
3985 bool
3988 {
3989 /* When checking and unless comparing DECL names, verify that if
3990 the outermost operand_equal_p call returns non-zero then ARG0
3991 and ARG1 have the same hash value. */
3993 {
3995 {
3997 {
4004 }
4006 }
4007 else
4011 }
4014 }
4019 /* Conveinece wrapper around operand_compare class because usually we do
4020 not need to play with the valueizer. */
4022 bool
4024 {
4026 }
4028 namespace inchash
4029 {
4031 /* Generate a hash value for an expression. This can be used iteratively
4032 by passing a previous result as the HSTATE argument.
4034 This function is intended to produce the same hash for expressions which
4035 would compare equal using operand_equal_p. */
4036 void
4038 {
4040 }
4042 }
4043 \f
4044 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
4045 with a different signedness or a narrower precision. */
4047 static bool
4049 {
4057 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4058 and see if the inner values are the same. This removes any
4059 signedness comparison, which doesn't matter here. */
4067 /* Discard a single widening conversion from ARG1 and see if the inner
4068 value is the same as ARG0. */
4077 }
4078 \f
4079 /* See if ARG is an expression that is either a comparison or is performing
4080 arithmetic on comparisons. The comparisons must only be comparing
4081 two different values, which will be stored in *CVAL1 and *CVAL2; if
4082 they are nonzero it means that some operands have already been found.
4083 No variables may be used anywhere else in the expression except in the
4084 comparisons.
4086 If this is true, return 1. Otherwise, return zero. */
4088 static bool
4090 {
4094 /* We can handle some of the tcc_expression cases here. */
4103 {
4122 /* First see if we can handle the first operand, then the second. For
4123 the second operand, we know *CVAL1 can't be zero. It must be that
4124 one side of the comparison is each of the values; test for the
4125 case where this isn't true by failing if the two operands
4126 are the same. */
4135 ;
4139 ;
4140 else
4144 ;
4148 ;
4149 else
4156 }
4157 }
4158 \f
4159 /* ARG is a tree that is known to contain just arithmetic operations and
4160 comparisons. Evaluate the operations in the tree substituting NEW0 for
4161 any occurrence of OLD0 as an operand of a comparison and likewise for
4162 NEW1 and OLD1. */
4164 static tree
4167 {
4172 /* We can handle some of the tcc_expression cases here. */
4180 {
4195 {
4214 }
4215 /* Fall through - ??? */
4218 {
4222 /* We need to check both for exact equality and tree equality. The
4223 former will be true if the operand has a side-effect. In that
4224 case, we know the operand occurred exactly once. */
4237 }
4241 }
4242 }
4243 \f
4244 /* Return a tree for the case when the result of an expression is RESULT
4245 converted to TYPE and OMITTED was previously an operand of the expression
4246 but is now not needed (e.g., we folded OMITTED * 0).
4248 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4249 the conversion of RESULT to TYPE. */
4251 tree
4253 {
4256 /* If the resulting operand is an empty statement, just return the omitted
4257 statement casted to void. */
4267 }
4269 /* Return a tree for the case when the result of an expression is RESULT
4270 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4271 of the expression but are now not needed.
4273 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4274 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4275 evaluated before OMITTED2. Otherwise, if neither has side effects,
4276 just do the conversion of RESULT to TYPE. */
4278 tree
4281 {
4290 }
4292 \f
4293 /* Return a simplified tree node for the truth-negation of ARG. This
4294 never alters ARG itself. We assume that ARG is an operation that
4295 returns a truth value (0 or 1).
4297 FIXME: one would think we would fold the result, but it causes
4298 problems with the dominator optimizer. */
4300 static tree
4302 {
4307 /* If this is a comparison, we can simply invert it, except for
4308 floating-point non-equality comparisons, in which case we just
4309 enclose a TRUTH_NOT_EXPR around what we have. */
4312 {
4315 && flag_trapping_math
4328 }
4331 {
4350 /* Here we can invert either operand. We invert the first operand
4351 unless the second operand is a TRUTH_NOT_EXPR in which case our
4352 result is the XOR of the first operand with the inside of the
4353 negation of the second operand. */
4358 else
4381 {
4388 /* A COND_EXPR may have a throw as one operand, which
4389 then has void type. Just leave void operands
4390 as they are. */
4396 }
4408 CASE_CONVERT:
4412 /* fall through */
4434 }
4435 }
4437 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4438 assume that ARG is an operation that returns a truth value (0 or 1
4439 for scalars, 0 or -1 for vectors). Return the folded expression if
4440 folding is successful. Otherwise, return NULL_TREE. */
4442 static tree
4444 {
4447 ? BIT_NOT_EXPR
4450 }
4452 /* Return a simplified tree node for the truth-negation of ARG. This
4453 never alters ARG itself. We assume that ARG is an operation that
4454 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4456 tree
4458 {
4464 ? BIT_NOT_EXPR
4467 }
4468 \f
4469 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4470 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4471 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4472 is the original memory reference used to preserve the alias set of
4473 the access. */
4475 static tree
4479 {
4482 /* Attempt not to lose the access path if possible. */
4484 {
4486 machine_mode nmode;
4488 tree noffset;
4496 && !reversep
4497 && !nreversep
4499 {
4502 }
4503 }
4512 {
4519 }
4534 }
4536 /* Optimize a bit-field compare.
4538 There are two cases: First is a compare against a constant and the
4539 second is a comparison of two items where the fields are at the same
4540 bit position relative to the start of a chunk (byte, halfword, word)
4541 large enough to contain it. In these cases we can avoid the shift
4542 implicit in bitfield extractions.
4544 For constants, we emit a compare of the shifted constant with the
4545 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4546 compared. For two fields at the same position, we do the ANDs with the
4547 similar mask and compare the result of the ANDs.
4549 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4550 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4551 are the left and right operands of the comparison, respectively.
4553 If the optimization described above can be done, we return the resulting
4554 tree. Otherwise we return zero. */
4556 static tree
4559 {
4563 tree unsigned_type;
4566 scalar_int_mode nmode;
4571 tree mask;
4572 tree offset;
4574 /* Get all the information about the extractions being done. If the bit size
4575 is the same as the size of the underlying object, we aren't doing an
4576 extraction at all and so can do nothing. We also don't want to
4577 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4578 then will no longer be able to replace it. */
4593 else
4594 {
4595 /* If this is not a constant, we can only do something if bit positions,
4596 sizes, signedness and storage order are the same. */
4597 rinner
4610 }
4612 /* Honor the C++ memory model and mimic what RTL expansion does. */
4616 {
4620 }
4622 /* See if we can find a mode to refer to this field. We should be able to,
4623 but fail if we can't. */
4631 /* Set signed and unsigned types of the precision of this mode for the
4632 shifts below. */
4635 /* Compute the bit position and size for the new reference and our offset
4636 within it. If the new reference is the same size as the original, we
4637 won't optimize anything, so return zero. */
4647 /* Make the mask to be used against the extracted field. */
4654 {
4658 /* If not comparing with constant, just rework the comparison
4659 and return. */
4667 }
4669 /* Otherwise, we are handling the constant case. See if the constant is too
4670 big for the field. Warn and return a tree for 0 (false) if so. We do
4671 this not only for its own sake, but to avoid having to test for this
4672 error case below. If we didn't, we might generate wrong code.
4674 For unsigned fields, the constant shifted right by the field length should
4675 be all zero. For signed fields, the high-order bits should agree with
4676 the sign bit. */
4679 {
4681 {
4685 }
4686 }
4687 else
4688 {
4691 {
4695 }
4696 }
4701 /* Single-bit compares should always be against zero. */
4703 {
4706 }
4708 /* Make a new bitfield reference, shift the constant over the
4709 appropriate number of bits and mask it with the computed mask
4710 (in case this was a signed field). If we changed it, make a new one. */
4718 mask);
4723 }
4724 \f
4725 /* Subroutine for fold_truth_andor_1: decode a field reference.
4727 If EXP is a comparison reference, we return the innermost reference.
4729 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4730 set to the starting bit number.
4732 If the innermost field can be completely contained in a mode-sized
4733 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4735 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4736 otherwise it is not changed.
4738 *PUNSIGNEDP is set to the signedness of the field.
4740 *PREVERSEP is set to the storage order of the field.
4742 *PMASK is set to the mask used. This is either contained in a
4743 BIT_AND_EXPR or derived from the width of the field.
4745 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4747 Return 0 if this is not a component reference or is one that we can't
4748 do anything with. */
4750 static tree
4755 {
4760 tree unsigned_type;
4763 /* All the optimizations using this function assume integer fields.
4764 There are problems with FP fields since the type_for_size call
4765 below can fail for, e.g., XFmode. */
4769 /* We are interested in the bare arrangement of bits, so strip everything
4770 that doesn't affect the machine mode. However, record the type of the
4771 outermost expression if it may matter below. */
4778 {
4784 }
4795 /* Reject out-of-bound accesses (PR79731). */
4807 /* If the number of bits in the reference is the same as the bitsize of
4808 the outer type, then the outer type gives the signedness. Otherwise
4809 (in case of a small bitfield) the signedness is unchanged. */
4813 /* Compute the mask to access the bitfield. */
4821 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4829 }
4831 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4832 bit positions and MASK is SIGNED. */
4834 static bool
4836 {
4840 /* If this function returns true when the type of the mask is
4841 UNSIGNED, then there will be errors. In particular see
4842 gcc.c-torture/execute/990326-1.c. There does not appear to be
4843 any documentation paper trail as to why this is so. But the pre
4844 wide-int worked with that restriction and it has been preserved
4845 here. */
4850 }
4852 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4853 represents the sign bit of EXP's type. If EXP represents a sign
4854 or zero extension, also test VAL against the unextended type.
4855 The return value is the (sub)expression whose sign bit is VAL,
4856 or NULL_TREE otherwise. */
4858 tree
4860 {
4862 tree t;
4864 /* Tree EXP must have an integral type. */
4869 /* Tree VAL must be an integer constant. */
4878 /* Handle extension from a narrower type. */
4884 }
4886 /* Subroutine for fold_truth_andor_1 and simple_condition_p: determine if an
4887 operand is simple enough to be evaluated unconditionally. */
4889 static bool
4891 {
4892 /* Strip any conversions that don't change the machine mode. */
4901 /* Don't regard global variables as simple. They may be
4902 allocated in ways unknown to the compiler (shared memory,
4903 #pragma weak, etc). */
4906 /* Weakrefs are not safe to be read, since they can be NULL.
4907 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4908 have DECL_WEAK flag set. */
4910 /* Loading a static variable is unduly expensive, but global
4911 registers aren't expensive. */
4913 }
4915 /* Determine if an operand is simple enough to be evaluated unconditionally.
4916 In addition to simple_operand_p, we assume that comparisons, conversions,
4917 and logic-not operations are simple, if their operands are simple, too. */
4919 bool
4921 {
4940 }
4942 \f
4943 /* The following functions are subroutines to fold_range_test and allow it to
4944 try to change a logical combination of comparisons into a range test.
4946 For example, both
4947 X == 2 || X == 3 || X == 4 || X == 5
4948 and
4949 X >= 2 && X <= 5
4950 are converted to
4951 (unsigned) (X - 2) <= 3
4953 We describe each set of comparisons as being either inside or outside
4954 a range, using a variable named like IN_P, and then describe the
4955 range with a lower and upper bound. If one of the bounds is omitted,
4956 it represents either the highest or lowest value of the type.
4958 In the comments below, we represent a range by two numbers in brackets
4959 preceded by a "+" to designate being inside that range, or a "-" to
4960 designate being outside that range, so the condition can be inverted by
4961 flipping the prefix. An omitted bound is represented by a "-". For
4962 example, "- [-, 10]" means being outside the range starting at the lowest
4963 possible value and ending at 10, in other words, being greater than 10.
4964 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4965 always false.
4967 We set up things so that the missing bounds are handled in a consistent
4968 manner so neither a missing bound nor "true" and "false" need to be
4969 handled using a special case. */
4971 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4972 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4973 and UPPER1_P are nonzero if the respective argument is an upper bound
4974 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4975 must be specified for a comparison. ARG1 will be converted to ARG0's
4976 type if both are specified. */
4978 static tree
4981 {
4982 tree tem;
4986 /* If neither arg represents infinity, do the normal operation.
4987 Else, if not a comparison, return infinity. Else handle the special
4988 comparison rules. Note that most of the cases below won't occur, but
4989 are handled for consistency. */
4992 {
4997 }
5002 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
5003 for neither. In real maths, we cannot assume open ended ranges are
5004 the same. But, this is computer arithmetic, where numbers are finite.
5005 We can therefore make the transformation of any unbounded range with
5006 the value Z, Z being greater than any representable number. This permits
5007 us to treat unbounded ranges as equal. */
5011 {
5032 }
5035 }
5036 \f
5037 /* Helper routine for make_range. Perform one step for it, return
5038 new expression if the loop should continue or NULL_TREE if it should
5039 stop. */
5041 tree
5045 {
5051 {
5053 /* We can only do something if the range is testing for zero. */
5062 /* We can only do something if the range is testing for zero
5063 and if the second operand is an integer constant. Note that
5064 saying something is "in" the range we make is done by
5065 complementing IN_P since it will set in the initial case of
5066 being not equal to zero; "out" is leaving it alone. */
5073 {
5094 }
5096 /* If this is an unsigned comparison, we also know that EXP is
5097 greater than or equal to zero. We base the range tests we make
5098 on that fact, so we record it here so we can parse existing
5099 range tests. We test arg0_type since often the return type
5100 of, e.g. EQ_EXPR, is boolean. */
5102 {
5106 NULL_TREE))
5111 /* If the high bound is missing, but we have a nonzero low
5112 bound, reverse the range so it goes from zero to the low bound
5113 minus 1. */
5115 {
5120 }
5121 }
5129 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5130 low and high are non-NULL, then normalize will DTRT. */
5133 {
5138 }
5140 /* (-x) IN [a,b] -> x in [-b, -a] */
5152 /* ~ X -> -X - 1 */
5161 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5162 move a constant to the other side. */
5167 /* If EXP is signed, any overflow in the computation is undefined,
5168 so we don't worry about it so long as our computations on
5169 the bounds don't overflow. For unsigned, overflow is defined
5170 and this is exactly the right thing. */
5182 normalize:
5183 /* Check for an unsigned range which has wrapped around the maximum
5184 value thus making n_high < n_low, and normalize it. */
5186 {
5192 /* If the range is of the form +/- [ x+1, x ], we won't
5193 be able to normalize it. But then, it represents the
5194 whole range or the empty set, so make it
5195 +/- [ -, - ]. */
5199 else
5201 }
5202 else
5210 CASE_CONVERT:
5228 /* If we're converting arg0 from an unsigned type, to exp,
5229 a signed type, we will be doing the comparison as unsigned.
5230 The tests above have already verified that LOW and HIGH
5231 are both positive.
5233 So we have to ensure that we will handle large unsigned
5234 values the same way that the current signed bounds treat
5235 negative values. */
5238 {
5239 tree high_positive;
5240 tree equiv_type;
5241 /* For fixed-point modes, we need to pass the saturating flag
5242 as the 2nd parameter. */
5244 equiv_type
5247 else
5248 equiv_type
5251 /* A range without an upper bound is, naturally, unbounded.
5252 Since convert would have cropped a very large value, use
5253 the max value for the destination type. */
5254 high_positive
5261 high_positive),
5264 /* If the low bound is specified, "and" the range with the
5265 range for which the original unsigned value will be
5266 positive. */
5268 {
5271 integer_zero_node),
5272 high_positive))
5276 }
5277 else
5278 {
5279 /* Otherwise, "or" the range with the range of the input
5280 that will be interpreted as negative. */
5283 integer_zero_node),
5284 high_positive))
5288 }
5289 }
5291 /* Otherwise, if we are converting arg0 from signed type, to exp,
5292 an unsigned type, we will do the comparison as signed. If
5293 high is non-NULL, we punt above if it doesn't fit in the signed
5294 type, so if we get through here, +[-, high] or +[low, high] are
5295 equivalent to +[-, n_high] or +[n_low, n_high]. Similarly,
5296 +[-, -] or -[-, -] are equivalent too. But if low is specified and
5297 high is not, the +[low, -] range is equivalent to union of
5298 +[n_low, -] and +[-, -1] ranges, so +[low, -] is equivalent to
5299 -[0, n_low-1] and similarly -[low, -] to +[0, n_low-1], except for
5300 low being 0, which should be treated as [-, -]. */
5303 && low
5305 {
5308 else
5309 {
5314 }
5315 }
5324 }
5325 }
5327 /* Given EXP, a logical expression, set the range it is testing into
5328 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5329 actually being tested. *PLOW and *PHIGH will be made of the same
5330 type as the returned expression. If EXP is not a comparison, we
5331 will most likely not be returning a useful value and range. Set
5332 *STRICT_OVERFLOW_P to true if the return value is only valid
5333 because signed overflow is undefined; otherwise, do not change
5334 *STRICT_OVERFLOW_P. */
5336 tree
5339 {
5347 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5348 and see if we can refine the range. Some of the cases below may not
5349 happen, but it doesn't seem worth worrying about this. We "continue"
5350 the outer loop when we've changed something; otherwise we "break"
5351 the switch, which will "break" the while. */
5357 {
5363 {
5371 }
5380 }
5382 /* If EXP is a constant, we can evaluate whether this is true or false. */
5384 {
5391 }
5395 }
5397 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5398 a bitwise check i.e. when
5399 LOW == 0xXX...X00...0
5400 HIGH == 0xXX...X11...1
5401 Return corresponding mask in MASK and stem in VALUE. */
5403 static bool
5406 {
5429 }
5430 \f
5431 /* Helper routine for build_range_check and match.pd. Return the type to
5432 perform the check or NULL if it shouldn't be optimized. */
5434 tree
5436 {
5437 /* First make sure that arithmetics in this type is valid, then make sure
5438 that it wraps around. */
5443 {
5446 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5447 for the type in question, as we rely on this here. */
5457 else
5459 }
5463 }
5465 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5466 type, TYPE, return an expression to test if EXP is in (or out of, depending
5467 on IN_P) the range. Return 0 if the test couldn't be created. */
5469 tree
5472 {
5475 /* Disable this optimization for function pointer expressions
5476 on targets that require function pointer canonicalization. */
5483 {
5489 }
5511 value);
5514 {
5516 {
5520 }
5522 }
5524 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5526 {
5530 {
5532 {
5535 etype
5537 else
5540 }
5543 }
5544 }
5546 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5547 This requires wrap-around arithmetics for the type of the expression. */
5564 }
5565 \f
5566 /* Return the predecessor of VAL in its type, handling the infinite case. */
5568 static tree
5570 {
5576 else
5579 }
5581 /* Return the successor of VAL in its type, handling the infinite case. */
5583 static tree
5585 {
5591 else
5594 }
5596 /* Given two ranges, see if we can merge them into one. Return 1 if we
5597 can, 0 if we can't. Set the output range into the specified parameters. */
5599 bool
5602 {
5606 tree tem;
5616 /* Make range 0 be the range that starts first, or ends last if they
5617 start at the same value. Swap them if it isn't. */
5620 || (lowequal
5623 {
5627 }
5629 /* If the second range is != high1 where high1 is the type maximum of
5630 the type, try first merging with < high1 range. */
5632 && high1
5639 {
5644 /* Similarly for the second range != low1 where low1 is the type minimum
5645 of the type, try first merging with > low1 range. */
5650 }
5652 /* Now flag two cases, whether the ranges are disjoint or whether the
5653 second range is totally subsumed in the first. Note that the tests
5654 below are simplified by the ones above. */
5660 /* We now have four cases, depending on whether we are including or
5661 excluding the two ranges. */
5663 {
5664 /* If they don't overlap, the result is false. If the second range
5665 is a subset it is the result. Otherwise, the range is from the start
5666 of the second to the end of the first. */
5671 else
5673 }
5676 {
5677 /* If they don't overlap, the result is the first range. If they are
5678 equal, the result is false. If the second range is a subset of the
5679 first, and the ranges begin at the same place, we go from just after
5680 the end of the second range to the end of the first. If the second
5681 range is not a subset of the first, or if it is a subset and both
5682 ranges end at the same place, the range starts at the start of the
5683 first range and ends just before the second range.
5684 Otherwise, we can't describe this as a single range. */
5690 {
5695 {
5696 /* We are in the weird situation where high0 > high1 but
5697 high1 has no successor. Punt. */
5699 }
5700 }
5702 {
5707 {
5708 /* low0 < low1 but low1 has no predecessor. Punt. */
5710 }
5711 }
5712 else
5714 }
5717 {
5718 /* If they don't overlap, the result is the second range. If the second
5719 is a subset of the first, the result is false. Otherwise,
5720 the range starts just after the first range and ends at the
5721 end of the second. */
5726 else
5727 {
5732 {
5733 /* high1 > high0 but high0 has no successor. Punt. */
5735 }
5736 }
5737 }
5739 else
5740 {
5741 /* The case where we are excluding both ranges. Here the complex case
5742 is if they don't overlap. In that case, the only time we have a
5743 range is if they are adjacent. If the second is a subset of the
5744 first, the result is the first. Otherwise, the range to exclude
5745 starts at the beginning of the first range and ends at the end of the
5746 second. */
5748 {
5753 else
5754 {
5755 /* Canonicalize - [min, x] into - [-, x]. */
5758 {
5761 GET_MODE_BITSIZE
5764 /* FALLTHROUGH */
5777 }
5779 /* Canonicalize - [x, max] into - [x, -]. */
5782 {
5785 GET_MODE_BITSIZE
5788 /* FALLTHROUGH */
5804 }
5806 /* The ranges might be also adjacent between the maximum and
5807 minimum values of the given type. For
5808 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5809 return + [x + 1, y - 1]. */
5811 {
5818 }
5819 else
5821 }
5822 }
5825 else
5827 }
5831 }
5832 \f
5834 /* Subroutine of fold, looking inside expressions of the form
5835 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5836 are the three operands of the COND_EXPR. This function is
5837 being used also to optimize A op B ? C : A, by reversing the
5838 comparison first.
5840 Return a folded expression whose code is not a COND_EXPR
5841 anymore, or NULL_TREE if no folding opportunity is found. */
5843 static tree
5847 {
5849 tree tem;
5854 /* If we have A op 0 ? A : -A, consider applying the following
5855 transformations:
5857 A == 0? A : -A same as -A
5858 A != 0? A : -A same as A
5859 A >= 0? A : -A same as abs (A)
5860 A > 0? A : -A same as abs (A)
5861 A <= 0? A : -A same as -abs (A)
5862 A < 0? A : -A same as -abs (A)
5864 None of these transformations work for modes with signed
5865 zeros. If A is +/-0, the first two transformations will
5866 change the sign of the result (from +0 to -0, or vice
5867 versa). The last four will fix the sign of the result,
5868 even though the original expressions could be positive or
5869 negative, depending on the sign of A.
5871 Note that all these transformations are correct if A is
5872 NaN, since the two alternatives (A and -A) are also NaNs. */
5879 /* In the case that A is of the form X-Y, '-A' (arg2) may
5880 have already been folded to Y-X, check for that. */
5888 {
5900 /* Fall through. */
5911 /* FALLTHRU */
5918 {
5919 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5920 is not, invokes UB both in abs and in the negation of it.
5921 So, use ABSU_EXPR instead. */
5926 }
5927 else
5928 {
5931 }
5935 }
5937 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5938 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5939 both transformations are correct when A is NaN: A != 0
5940 is then true, and A == 0 is false. */
5944 {
5949 }
5951 /* Try some transformations of A op B ? A : B.
5953 A == B? A : B same as B
5954 A != B? A : B same as A
5955 A >= B? A : B same as max (A, B)
5956 A > B? A : B same as max (B, A)
5957 A <= B? A : B same as min (A, B)
5958 A < B? A : B same as min (B, A)
5960 As above, these transformations don't work in the presence
5961 of signed zeros. For example, if A and B are zeros of
5962 opposite sign, the first two transformations will change
5963 the sign of the result. In the last four, the original
5964 expressions give different results for (A=+0, B=-0) and
5965 (A=-0, B=+0), but the transformed expressions do not.
5967 The first two transformations are correct if either A or B
5968 is a NaN. In the first transformation, the condition will
5969 be false, and B will indeed be chosen. In the case of the
5970 second transformation, the condition A != B will be true,
5971 and A will be chosen.
5973 The conversions to max() and min() are not correct if B is
5974 a number and A is not. The conditions in the original
5975 expressions will be false, so all four give B. The min()
5976 and max() versions would give a NaN instead. */
5979 /* Avoid these transformations if the COND_EXPR may be used
5980 as an lvalue in the C++ front-end. PR c++/19199. */
5981 && (in_gimple_form
5987 {
5993 {
6002 /* In C++ a ?: expression can be an lvalue, so put the
6003 operand which will be used if they are equal first
6004 so that we can convert this back to the
6005 corresponding COND_EXPR. */
6007 {
6015 }
6022 {
6030 }
6043 }
6044 }
6047 }
6050 \f
6051 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
6052 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
6053 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
6054 false) >= 2)
6055 #endif
6057 /* EXP is some logical combination of boolean tests. See if we can
6058 merge it into some range test. Return the new tree if so. */
6060 static tree
6063 {
6077 /* If op0 is known true or false and this is a short-circuiting
6078 operation we must not merge with op1 since that makes side-effects
6079 unconditional. So special-case this. */
6086 /* If this is an OR operation, invert both sides; we will invert
6087 again at the end. */
6091 /* If both expressions are the same, if we can merge the ranges, and we
6092 can build the range test, return it or it inverted. If one of the
6093 ranges is always true or always false, consider it to be the same
6094 expression as the other. */
6102 {
6106 }
6108 /* On machines where the branch cost is expensive, if this is a
6109 short-circuited branch and the underlying object on both sides
6110 is the same, make a non-short-circuit operation. */
6113 logical_op_non_short_circuit
6120 {
6121 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6122 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6123 which cases we can't do this. */
6131 {
6140 {
6143 WARN_STRICT_OVERFLOW_COMPARISON);
6147 }
6148 }
6149 }
6152 }
6153 \f
6154 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6155 bit value. Arrange things so the extra bits will be set to zero if and
6156 only if C is signed-extended to its full width. If MASK is nonzero,
6157 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6159 static tree
6161 {
6164 tree temp;
6169 /* We work by getting just the sign bit into the low-order bit, then
6170 into the high-order bit, then sign-extend. We then XOR that value
6171 with C. */
6175 /* We must use a signed type in order to get an arithmetic right shift.
6176 However, we must also avoid introducing accidental overflows, so that
6177 a subsequent call to integer_zerop will work. Hence we must
6178 do the type conversion here. At this point, the constant is either
6179 zero or one, and the conversion to a signed type can never overflow.
6180 We could get an overflow if this conversion is done anywhere else. */
6189 /* If necessary, convert the type back to match the type of C. */
6194 }
6195 \f
6196 /* For an expression that has the form
6197 (A && B) || ~B
6198 or
6199 (A || B) && ~B,
6200 we can drop one of the inner expressions and simplify to
6201 A || ~B
6202 or
6203 A && ~B
6204 LOC is the location of the resulting expression. OP is the inner
6205 logical operation; the left-hand side in the examples above, while CMPOP
6206 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6207 removing a condition that guards another, as in
6208 (A != NULL && A->...) || A == NULL
6209 which we must not transform. If RHS_ONLY is true, only eliminate the
6210 right-most operand of the inner logical operation. */
6212 static tree
6215 {
6233 {
6236 {
6239 }
6240 }
6242 {
6245 {
6248 }
6249 }
6264 }
6266 /* Find ways of folding logical expressions of LHS and RHS:
6267 Try to merge two comparisons to the same innermost item.
6268 Look for range tests like "ch >= '0' && ch <= '9'".
6269 Look for combinations of simple terms on machines with expensive branches
6270 and evaluate the RHS unconditionally.
6272 For example, if we have p->a == 2 && p->b == 4 and we can make an
6273 object large enough to span both A and B, we can do this with a comparison
6274 against the object ANDed with the a mask.
6276 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6277 operations to do this with one comparison.
6279 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6280 function and the one above.
6282 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6283 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6285 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6286 two operands.
6288 We return the simplified tree or 0 if no optimization is possible. */
6290 static tree
6293 {
6294 /* If this is the "or" of two comparisons, we can do something if
6295 the comparisons are NE_EXPR. If this is the "and", we can do something
6296 if the comparisons are EQ_EXPR. I.e.,
6297 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6299 WANTED_CODE is this operation code. For single bit fields, we can
6300 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6301 comparison for one-bit fields. */
6322 /* Start by getting the comparison codes. Fail if anything is volatile.
6323 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6324 it were surrounded with a NE_EXPR. */
6333 {
6337 }
6340 {
6344 }
6355 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6358 {
6361 {
6366 }
6369 {
6375 }
6376 }
6381 /* If the RHS can be evaluated unconditionally and its operands are
6382 simple, it wins to evaluate the RHS unconditionally on machines
6383 with expensive branches. In this case, this isn't a comparison
6384 that can be merged. */
6391 {
6392 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6403 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6413 }
6415 /* See if the comparisons can be merged. Then get all the parameters for
6416 each side. */
6441 /* It must be true that the inner operation on the lhs of each
6442 comparison must be the same if we are to be able to do anything.
6443 Then see if we have constants. If not, the same must be true for
6444 the rhs's. */
6453 {
6456 }
6461 else
6464 /* If either comparison code is not correct for our logical operation,
6465 fail. However, we can convert a one-bit comparison against zero into
6466 the opposite comparison against that bit being set in the field. */
6470 {
6472 {
6473 /* Make the left operand unsigned, since we are only interested
6474 in the value of one bit. Otherwise we are doing the wrong
6475 thing below. */
6478 }
6479 else
6481 }
6483 /* This is analogous to the code for l_const above. */
6485 {
6487 {
6490 }
6491 else
6493 }
6495 /* See if we can find a mode that contains both fields being compared on
6496 the left. If we can't, fail. Otherwise, update all constants and masks
6497 to be relative to a field of that size. */
6511 {
6514 }
6524 {
6533 {
6537 }
6538 }
6540 {
6549 {
6553 }
6554 }
6556 /* If the right sides are not constant, do the same for it. Also,
6557 disallow this optimization if a size, signedness or storage order
6558 mismatch occurs between the left and right sides. */
6560 {
6564 /* Make sure the two fields on the right
6565 correspond to the left without being swapped. */
6582 {
6585 }
6596 /* Make a mask that corresponds to both fields being compared.
6597 Do this for both items being compared. If the operands are the
6598 same size and the bits being compared are in the same position
6599 then we can do this by masking both and comparing the masked
6600 results. */
6607 {
6621 }
6623 /* There is still another way we can do something: If both pairs of
6624 fields being compared are adjacent, we may be able to make a wider
6625 field containing them both.
6627 Note that we still must mask the lhs/rhs expressions. Furthermore,
6628 the mask must be shifted to account for the shift done by
6629 make_bit_field_ref. */
6638 {
6639 tree type;
6657 /* Convert to the smaller type before masking out unwanted bits. */
6660 {
6662 {
6666 }
6668 {
6672 }
6673 }
6682 }
6685 }
6687 /* Handle the case of comparisons with constants. If there is something in
6688 common between the masks, those bits of the constants must be the same.
6689 If not, the condition is always false. Test for this to avoid generating
6690 incorrect code below. */
6695 {
6697 {
6700 }
6701 else
6702 {
6705 }
6706 }
6711 /* Construct the expression we will return. First get the component
6712 reference we will make. Unless the mask is all ones the width of
6713 that field, perform the mask operation. Then compare with the
6714 merged constant. */
6725 }
6726 \f
6727 /* T is an integer expression that is being multiplied, divided, or taken a
6728 modulus (CODE says which and what kind of divide or modulus) by a
6729 constant C. See if we can eliminate that operation by folding it with
6730 other operations already in T. WIDE_TYPE, if non-null, is a type that
6731 should be used for the computation if wider than our type.
6733 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6734 (X * 2) + (Y * 4). We must, however, be assured that either the original
6735 expression would not overflow or that overflow is undefined for the type
6736 in the language in question.
6738 If we return a non-null expression, it is an equivalent form of the
6739 original computation, but need not be in the original type.
6741 We set *STRICT_OVERFLOW_P to true if the return values depends on
6742 signed overflow being undefined. Otherwise we do not change
6743 *STRICT_OVERFLOW_P. */
6745 static tree
6748 {
6749 /* To avoid exponential search depth, refuse to allow recursion past
6750 three levels. Beyond that (1) it's highly unlikely that we'll find
6751 something interesting and (2) we've probably processed it before
6752 when we built the inner expression. */
6755 tree ret;
6760 depth++;
6762 depth--;
6765 }
6767 static tree
6770 {
6782 /* Don't deal with constants of zero here; they confuse the code below. */
6792 /* Note that we need not handle conditional operations here since fold
6793 already handles those cases. So just do arithmetic here. */
6795 {
6797 /* For a constant, we can always simplify if we are a multiply
6798 or (for divide and modulus) if it is a multiple of our constant. */
6802 {
6805 /* If the multiplication overflowed, we lost information on it.
6806 See PR68142 and PR69845. */
6810 }
6816 /* If op0 is an expression ... */
6822 /* ... and has wrapping overflow, and its type is smaller
6823 than ctype, then we cannot pass through as widening. */
6827 /* ... or this is a truncation (t is narrower than op0),
6828 then we cannot pass through this narrowing. */
6831 /* ... or signedness changes for division or modulus,
6832 then we cannot pass through this conversion. */
6836 /* ... or has undefined overflow while the converted to
6837 type has not, we cannot do the operation in the inner type
6838 as that would introduce undefined overflow. */
6843 /* Pass the constant down and see if we can make a simplification. If
6844 we can, replace this expression with the inner simplification for
6845 possible later conversion to our or some other type. */
6856 /* If widening the type changes it from signed to unsigned, then we
6857 must avoid building ABS_EXPR itself as unsigned. */
6859 {
6863 {
6866 }
6868 }
6869 /* If the constant is negative, we cannot simplify this. */
6872 /* FALLTHROUGH */
6874 /* For division and modulus, type can't be unsigned, as e.g.
6875 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6876 For signed types, even with wrapping overflow, this is fine. */
6885 /* If widening the type changes the signedness, then we can't perform
6886 this optimization as that changes the result. */
6890 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6896 {
6903 }
6907 /* If the second operand is constant, this is a multiplication
6908 or floor division, by a power of two, so we can treat it that
6909 way unless the multiplier or divisor overflows. Signed
6910 left-shift overflow is implementation-defined rather than
6911 undefined in C90, so do not convert signed left shift into
6912 multiplication. */
6915 /* const_binop may not detect overflow correctly,
6916 so check for it explicitly here. */
6925 ctype,
6927 t1),
6932 /* See if we can eliminate the operation on both sides. If we can, we
6933 can return a new PLUS or MINUS. If we can't, the only remaining
6934 cases where we can do anything are if the second operand is a
6935 constant. */
6942 /* If not multiplication, we can only do this if both operands
6943 are divisible by c. */
6946 {
6951 }
6953 /* If this was a subtraction, negate OP1 and set it to be an addition.
6954 This simplifies the logic below. */
6956 {
6958 /* If OP1 was not easily negatable, the constant may be OP0. */
6960 {
6963 }
6964 }
6969 /* If either OP1 or C are negative, this optimization is not safe for
6970 some of the division and remainder types while for others we need
6971 to change the code. */
6973 {
6981 }
6983 /* If it's a multiply or a division/modulus operation of a multiple
6984 of our constant, do the operation and verify it doesn't overflow. */
6988 {
6991 /* We allow the constant to overflow with wrapping semantics. */
6995 }
6996 else
6999 /* If we have an unsigned type, we cannot widen the operation since it
7000 will change the result if the original computation overflowed. */
7004 /* The last case is if we are a multiply. In that case, we can
7005 apply the distributive law to commute the multiply and addition
7006 if the multiplication of the constants doesn't overflow
7007 and overflow is defined. With undefined overflow
7008 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
7009 But fold_plusminus_mult_expr would factor back any power-of-two
7010 value so do not distribute in the first place in this case. */
7018 op1);
7023 /* We have a special case here if we are doing something like
7024 (C * 8) % 4 since we know that's zero. */
7027 /* If the multiplication can overflow we cannot optimize this. */
7032 {
7035 }
7037 /* ... fall through ... */
7041 /* If we can extract our operation from the LHS, do so and return a
7042 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
7043 do something only if the second operand is a constant. */
7059 /* If these are the same operation types, we can associate them
7060 assuming no overflow. */
7062 {
7077 }
7079 /* If these operations "cancel" each other, we have the main
7080 optimizations of this pass, which occur when either constant is a
7081 multiple of the other, in which case we replace this with either an
7082 operation or CODE or TCODE.
7084 If we have an unsigned type, we cannot do this since it will change
7085 the result if the original computation overflowed. */
7092 {
7095 {
7102 }
7105 {
7112 }
7113 }
7118 }
7121 }
7122 \f
7123 /* Return a node which has the indicated constant VALUE (either 0 or
7124 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7125 and is of the indicated TYPE. */
7127 tree
7129 {
7138 else
7140 }
7143 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7144 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7145 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7146 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7147 COND is the first argument to CODE; otherwise (as in the example
7148 given here), it is the second argument. TYPE is the type of the
7149 original expression. Return NULL_TREE if no simplification is
7150 possible. */
7152 static tree
7157 {
7165 /* Do not move possibly trapping operations into the conditional as this
7166 pessimizes code and causes gimplification issues when applied late. */
7174 {
7178 /* If this operand throws an expression, then it does not make
7179 sense to try to perform a logical or arithmetic operation
7180 involving it. */
7185 }
7188 {
7193 }
7194 else
7195 /* Detect the case of mixing vector and scalar types - bail out. */
7201 /* This transformation is only worthwhile if we don't have to wrap ARG
7202 in a SAVE_EXPR and the operation can be simplified without recursing
7203 on at least one of the branches once its pushed inside the COND_EXPR. */
7212 {
7216 else
7218 }
7220 {
7224 else
7226 }
7228 /* Check that we have simplified at least one of the branches. */
7233 }
7235 \f
7236 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7238 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7239 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7240 if ARG - ZERO_ARG is the same as X.
7242 If ARG is NULL, check for any value of type TYPE.
7244 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7245 and finite. The problematic cases are when X is zero, and its mode
7246 has signed zeros. In the case of rounding towards -infinity,
7247 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7248 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7250 bool
7253 {
7257 /* Don't allow the fold with -fsignaling-nans. */
7261 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7265 /* There is no case that is safe for all rounding modes. */
7269 /* In a vector or complex, we would need to check the sign of all zeros. */
7275 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7279 /* The mode has signed zeros, and we have to honor their sign.
7280 In this situation, there are only two cases we can return true for.
7281 (i) X - 0 is the same as X with default rounding.
7282 (ii) X + 0 is X when X can't possibly be -0.0. */
7284 }
7286 /* Subroutine of match.pd that optimizes comparisons of a division by
7287 a nonzero integer constant against an integer constant, i.e.
7288 X/C1 op C2.
7290 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7291 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7293 enum tree_code
7296 {
7301 /* We have to do this the hard way to detect unsigned overflow.
7302 prod = int_const_binop (MULT_EXPR, c1, c2); */
7308 {
7312 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7315 }
7317 {
7320 {
7339 }
7340 }
7341 else
7342 {
7343 /* A negative divisor reverses the relational operators. */
7348 {
7367 }
7368 }
7381 }
7384 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7385 equality/inequality test, then return a simplified form of the test
7386 using a sign testing. Otherwise return NULL. TYPE is the desired
7387 result type. */
7389 static tree
7392 tree result_type)
7393 {
7394 /* If this is testing a single bit, we can optimize the test. */
7398 {
7399 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7400 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7404 /* This is only a win if casting to a signed type is cheap,
7405 i.e. when arg00's type is not a partial mode. */
7407 {
7410 result_type,
7413 }
7414 }
7417 }
7419 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7420 equality/inequality test, then return a simplified form of
7421 the test using shifts and logical operations. Otherwise return
7422 NULL. TYPE is the desired result type. */
7424 tree
7427 {
7428 /* If this is testing a single bit, we can optimize the test. */
7432 {
7441 /* First, see if we can fold the single bit test into a sign-bit
7442 test. */
7444 result_type);
7448 /* Otherwise we have (A & C) != 0 where C is a single bit,
7449 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7450 Similarly for (A & C) == 0. */
7452 /* If INNER is a right shift of a constant and it plus BITNUM does
7453 not overflow, adjust BITNUM and INNER. */
7459 {
7462 }
7464 /* If we are going to be able to omit the AND below, we must do our
7465 operations as unsigned. If we must use the AND, we have a choice.
7466 Normally unsigned is faster, but for some machines signed is. */
7484 /* Put the AND last so it can combine with more things. */
7487 /* Make sure to return the proper type. */
7491 }
7493 }
7495 /* Test whether it is preferable to swap two operands, ARG0 and
7496 ARG1, for example because ARG0 is an integer constant and ARG1
7497 isn't. */
7499 bool
7501 {
7515 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7516 for commutative and comparison operators. Ensuring a canonical
7517 form allows the optimizers to find additional redundancies without
7518 having to explicitly check for both orderings. */
7524 /* Put SSA_NAMEs last. */
7530 /* Put variables last. */
7537 }
7540 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7541 means A >= Y && A != MAX, but in this case we know that
7542 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7544 static tree
7546 {
7553 else
7562 {
7565 }
7567 {
7570 }
7571 else
7578 {
7579 /* Convert the pointer types into integer before taking the difference. */
7583 }
7584 else
7591 }
7593 /* Fold a sum or difference of at least one multiplication.
7594 Returns the folded tree or NULL if no simplification could be made. */
7596 static tree
7599 {
7603 /* (A * C) +- (B * C) -> (A+-B) * C.
7604 (A * C) +- A -> A * (C+-1).
7605 We are most concerned about the case where C is a constant,
7606 but other combinations show up during loop reduction. Since
7607 it is not difficult, try all four possibilities. */
7610 {
7613 }
7615 {
7618 }
7619 else
7620 {
7621 /* We cannot generate constant 1 for fract. */
7626 }
7628 {
7631 }
7633 {
7635 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7636 the purpose of this canonicalization. */
7640 {
7643 }
7644 else
7646 }
7647 else
7648 {
7649 /* We cannot generate constant 1 for fract. */
7654 }
7657 /* Prefer factoring a common non-constant. */
7667 /* No identical multiplicands; see if we can find a common
7668 power-of-two factor in non-power-of-two multiplies. This
7669 can help in multi-dimensional array access. */
7671 {
7674 HOST_WIDE_INT tmp;
7676 tree maybe_same;
7678 /* Move min of absolute values to int11. */
7680 {
7685 }
7686 else
7693 /* The remainder should not be a constant, otherwise we
7694 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7695 increased the number of multiplications necessary. */
7697 {
7705 }
7706 }
7713 /* We are neither factoring zero nor minus one. */
7721 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7722 same may be minus one and thus the multiplication may overflow. Perform
7723 the sum operation in an unsigned type. */
7728 /* If the sum evaluated to a constant that is not -INF the multiplication
7729 cannot overflow. */
7736 /* Do not resort to unsigned multiplication because
7737 we lose the no-overflow property of the expression. */
7739 }
7741 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7742 specified by EXPR into the buffer PTR of length LEN bytes.
7743 Return the number of bytes placed in the buffer, or zero
7744 upon failure. */
7746 static int
7748 {
7760 /* Dry run. */
7766 {
7768 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7769 number of bytes. */
7773 {
7780 else
7782 }
7783 else
7787 }
7789 }
7792 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7793 specified by EXPR into the buffer PTR of length LEN bytes.
7794 Return the number of bytes placed in the buffer, or zero
7795 upon failure. */
7797 static int
7799 {
7803 FIXED_VALUE_TYPE value;
7818 }
7821 /* Subroutine of native_encode_expr. Encode the REAL_CST
7822 specified by EXPR into the buffer PTR of length LEN bytes.
7823 Return the number of bytes placed in the buffer, or zero
7824 upon failure. */
7826 static int
7828 {
7834 /* There are always 32 bits in each long, no matter the size of
7835 the hosts long. We handle floating point representations with
7836 up to 192 bits. */
7845 /* Dry run. */
7854 {
7859 {
7866 else
7868 }
7869 else
7870 {
7873 {
7874 /* Reverse bytes within each long, or within the entire float
7875 if it's smaller than a long (for HFmode). */
7878 }
7879 }
7884 }
7886 }
7888 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7889 specified by EXPR into the buffer PTR of length LEN bytes.
7890 Return the number of bytes placed in the buffer, or zero
7891 upon failure. */
7893 static int
7895 {
7897 tree part;
7911 }
7913 /* Like native_encode_vector, but only encode the first COUNT elements.
7914 The other arguments are as for native_encode_vector. */
7916 static int
7919 {
7923 {
7924 /* This is the only case in which elements can be smaller than a byte.
7925 Element 0 is always in the lsb of the containing byte. */
7934 /* Zero the buffer and then set bits later where necessary. */
7943 {
7949 {
7952 }
7953 }
7955 }
7960 {
7962 {
7965 }
7976 }
7978 }
7980 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7981 specified by EXPR into the buffer PTR of length LEN bytes.
7982 Return the number of bytes placed in the buffer, or zero
7983 upon failure. */
7985 static int
7987 {
7992 }
7995 /* Subroutine of native_encode_expr. Encode the STRING_CST
7996 specified by EXPR into the buffer PTR of length LEN bytes.
7997 Return the number of bytes placed in the buffer, or zero
7998 upon failure. */
8000 static int
8002 {
8005 /* Wide-char strings are encoded in target byte-order so native
8006 encoding them is trivial. */
8021 else
8022 {
8025 {
8028 }
8030 }
8032 }
8035 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
8036 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
8037 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
8038 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
8039 sufficient to encode the entire EXPR, or if OFF is out of bounds.
8040 Otherwise, start at byte offset OFF and encode at most LEN bytes.
8041 Return the number of bytes placed in the buffer, or zero upon failure. */
8043 int
8045 {
8046 /* We don't support starting at negative offset and -1 is special. */
8051 {
8072 }
8073 }
8075 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
8076 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
8077 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
8078 machine modes, we can't just use build_nonstandard_integer_type. */
8080 tree
8082 {
8083 machine_mode mode;
8085 {
8092 {
8096 }
8097 }
8103 {
8111 }
8114 }
8116 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8117 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8118 to be non-NULL and OFF zero), then in addition to filling the
8119 bytes pointed by PTR with the value also clear any bits pointed
8120 by MASK that are known to be initialized, keep them as is for
8121 e.g. uninitialized padding bits or uninitialized fields. */
8123 int
8126 {
8129 /* We don't support starting at negative offset and -1 is special. */
8137 {
8141 mask);
8156 {
8157 tree min_index;
8175 {
8180 {
8183 }
8188 else
8192 {
8196 offset_int wpos
8204 offset_int wcount
8211 }
8213 {
8216 offset_int wpos
8224 }
8227 {
8229 {
8240 }
8242 {
8246 }
8247 }
8251 do
8252 {
8257 {
8259 {
8262 fieldsize);
8265 }
8267 ptr
8270 fieldsize,
8273 mask
8277 else
8278 {
8281 }
8282 }
8285 {
8286 /* Partial overlap. */
8292 {
8296 fieldsize);
8297 }
8298 else
8299 {
8303 }
8306 }
8308 }
8310 }
8312 }
8315 {
8325 {
8331 {
8334 }
8337 {
8346 }
8350 else
8354 {
8355 tree fld;
8357 {
8370 }
8372 {
8376 }
8379 {
8380 cnt--;
8386 }
8387 }
8392 {
8405 {
8410 }
8411 }
8412 else
8413 {
8418 }
8423 {
8430 else
8436 }
8445 {
8446 /* FIXME: Handle PDP endian. */
8457 {
8460 }
8461 else
8462 {
8470 else
8471 {
8474 }
8475 }
8485 else
8498 /* If the bitfield does not start at byte boundary, handle
8499 the partial byte at the start. */
8502 {
8504 {
8509 {
8512 else
8514 }
8515 }
8516 else
8517 {
8522 {
8525 else
8529 }
8530 }
8531 }
8532 /* If the bitfield does not end at byte boundary, handle
8533 the partial byte at the end. */
8537 {
8539 {
8546 }
8547 else
8548 {
8555 }
8556 }
8560 {
8565 }
8566 else
8567 {
8568 /* Partial overlap. */
8572 {
8575 }
8579 }
8581 }
8586 {
8589 {
8592 {
8596 }
8599 }
8602 fldsize,
8612 }
8613 else
8614 {
8615 /* Partial overlap. */
8621 {
8625 fieldsize);
8626 }
8627 else
8628 {
8632 }
8635 }
8636 }
8638 }
8640 }
8641 }
8644 /* Subroutine of native_interpret_expr. Interpret the contents of
8645 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8646 If the buffer cannot be interpreted, return NULL_TREE. */
8648 static tree
8650 {
8660 }
8663 /* Subroutine of native_interpret_expr. Interpret the contents of
8664 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8665 If the buffer cannot be interpreted, return NULL_TREE. */
8667 static tree
8669 {
8672 double_int result;
8673 FIXED_VALUE_TYPE fixed_value;
8683 }
8686 /* Subroutine of native_interpret_expr. Interpret the contents of
8687 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8688 If the buffer cannot be interpreted, return NULL_TREE. */
8690 tree
8692 {
8696 /* There are always 32 bits in each long, no matter the size of
8697 the hosts long. We handle floating point representations with
8698 up to 192 bits. */
8699 REAL_VALUE_TYPE r;
8709 {
8710 /* Both OFFSET and BYTE index within a long;
8711 bitpos indexes the whole float. */
8714 {
8721 else
8723 }
8724 else
8725 {
8728 {
8729 /* Reverse bytes within each long, or within the entire float
8730 if it's smaller than a long (for HFmode). */
8733 }
8734 }
8738 }
8742 }
8745 /* Subroutine of native_interpret_expr. Interpret the contents of
8746 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8747 If the buffer cannot be interpreted, return NULL_TREE. */
8749 static tree
8751 {
8766 }
8768 /* Read a vector of type TYPE from the target memory image given by BYTES,
8769 which contains LEN bytes. The vector is known to be encodable using
8770 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8772 Return the vector on success, otherwise return null. */
8774 static tree
8778 {
8782 {
8783 /* This is the only case in which elements can be smaller than a byte.
8784 Element 0 is always in the lsb of the containing byte. */
8791 {
8798 }
8800 }
8808 {
8814 }
8816 }
8818 /* Subroutine of native_interpret_expr. Interpret the contents of
8819 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8820 If the buffer cannot be interpreted, return NULL_TREE. */
8822 static tree
8824 {
8825 tree etype;
8836 }
8839 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8840 the buffer PTR of length LEN as a constant of type TYPE. For
8841 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8842 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8843 return NULL_TREE. */
8845 tree
8847 {
8849 {
8860 {
8861 /* For floating point values in composite modes, punt if this
8862 folding doesn't preserve bit representation. As the mode doesn't
8863 have fixed precision while GCC pretends it does, there could be
8864 valid values that GCC can't really represent accurately.
8865 See PR95450. Even for other modes, e.g. x86 XFmode can have some
8866 bit combinationations which GCC doesn't preserve. */
8874 }
8888 }
8889 }
8891 /* Returns true if we can interpret the contents of a native encoding
8892 as TYPE. */
8894 bool
8896 {
8898 {
8912 }
8913 }
8915 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8916 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8918 tree
8921 {
8924 {
8931 {
8935 }
8940 {
8945 {
8950 }
8954 eltsz);
8958 }
8960 }
8964 {
8972 {
8975 {
8976 poly_int64 bitoffset;
8981 else
8991 }
8992 else
8993 {
9011 HOST_WIDE_INT rpos;
9014 else
9015 {
9018 }
9027 }
9028 }
9031 {
9041 }
9045 {
9050 }
9057 {
9061 /* FIXME: Figure out how to handle PDP endian bitfields. */
9067 else
9071 }
9073 }
9075 }
9077 /* Routines for manipulation of native_encode_expr encoded data if the encoded
9078 or extracted constant positions and/or sizes aren't byte aligned. */
9080 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
9081 bits between adjacent elements. AMNT should be within
9082 [0, BITS_PER_UNIT).
9083 Example, AMNT = 2:
9084 00011111|11100000 << 2 = 01111111|10000000
9085 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
9087 void
9090 {
9099 {
9105 {
9108 }
9109 }
9110 }
9112 /* Like shift_bytes_in_array_left but for big-endian.
9113 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9114 bits between adjacent elements. AMNT should be within
9115 [0, BITS_PER_UNIT).
9116 Example, AMNT = 2:
9117 00011111|11100000 >> 2 = 00000111|11111000
9118 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9120 void
9123 {
9131 {
9138 }
9139 }
9141 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9142 directly on the VECTOR_CST encoding, in a way that works for variable-
9143 length vectors. Return the resulting VECTOR_CST on success or null
9144 on failure. */
9146 static tree
9148 {
9160 /* We can only preserve the semantics of a stepped pattern if the new
9161 vector element is an integer of the same size. */
9166 /* The number of bits needed to encode one element from every pattern
9167 of the original vector. */
9168 unsigned int expr_sequence_bits
9171 /* The number of bits needed to encode one element from every pattern
9172 of the result. */
9173 unsigned int type_sequence_bits
9176 /* Don't try to read more bytes than are available, which can happen
9177 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9178 The general VIEW_CONVERT handling can cope with that case, so there's
9179 no point complicating things here. */
9182 BITS_PER_UNIT);
9187 /* Get enough bytes of EXPR to form the new encoding. */
9195 /* Reencode the bytes as TYPE. */
9199 }
9201 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9202 TYPE at compile-time. If we're unable to perform the conversion
9203 return NULL_TREE. */
9205 static tree
9207 {
9208 /* We support up to 512-bit values (for V8DFmode). */
9212 /* Check that the host and target are sane. */
9225 }
9227 /* Build an expression for the address of T. Folds away INDIRECT_REF
9228 to avoid confusing the gimplify process. */
9230 tree
9232 {
9233 /* The size of the object is not relevant when talking about its address. */
9238 {
9243 }
9246 {
9251 }
9258 {
9263 }
9264 else
9268 }
9270 /* Build an expression for the address of T. */
9272 tree
9274 {
9278 }
9280 /* Fold a unary expression of code CODE and type TYPE with operand
9281 OP0. Return the folded expression if folding is successful.
9282 Otherwise, return NULL_TREE. */
9284 tree
9286 {
9287 tree tem;
9288 tree arg0;
9296 {
9299 {
9300 /* Don't use STRIP_NOPS, because signedness of argument type
9301 matters. */
9303 }
9304 else
9305 {
9306 /* Strip any conversions that don't change the mode. This
9307 is safe for every expression, except for a comparison
9308 expression because its signedness is derived from its
9309 operands.
9311 Note that this is done as an internal manipulation within
9312 the constant folder, in order to find the simplest
9313 representation of the arguments so that their form can be
9314 studied. In any cases, the appropriate type conversions
9315 should be put back in the tree that will get out of the
9316 constant folder. */
9318 }
9321 {
9324 {
9328 }
9329 }
9330 }
9337 {
9344 {
9358 /* If this was a conversion, and all we did was to move into
9359 inside the COND_EXPR, bring it back out. But leave it if
9360 it is a conversion from integer to integer and the
9361 result precision is no wider than a word since such a
9362 conversion is cheap and may be optimized away by combine,
9363 while it couldn't if it were outside the COND_EXPR. Then return
9364 so we don't get into an infinite recursion loop taking the
9365 conversion out and then back in. */
9377 && (INTEGRAL_TYPE_P
9390 }
9391 }
9394 {
9400 CASE_CONVERT:
9404 {
9405 /* If we have (type) (a CMP b) and type is an integral type, return
9406 new expression involving the new type. Canonicalize
9407 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9408 non-integral type.
9409 Do not fold the result as that would not simplify further, also
9410 folding again results in recursions. */
9420 }
9422 /* Handle (T *)&A.B.C for A being of type T and B and C
9423 living at offset zero. This occurs frequently in
9424 C++ upcasting and then accessing the base. */
9428 {
9430 tree offset;
9431 machine_mode mode;
9433 tree base
9437 /* If the reference was to a (constant) zero offset, we can use
9438 the address of the base if it has the same base type
9439 as the result type and the pointer type is unqualified. */
9447 }
9451 /* Detect assigning a bitfield. */
9453 && DECL_BIT_FIELD
9455 {
9456 /* Don't leave an assignment inside a conversion
9457 unless assigning a bitfield. */
9459 /* First do the assignment, then return converted constant. */
9464 }
9466 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9467 constants (if x has signed type, the sign bit cannot be set
9468 in c). This folds extension into the BIT_AND_EXPR.
9469 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9470 very likely don't have maximal range for their precision and this
9471 transformation effectively doesn't preserve non-maximal ranges. */
9475 {
9486 <= HOST_BITS_PER_WIDE_INT
9488 {
9492 cst &= HOST_WIDE_INT_M1U
9496 && !flag_syntax_only
9499 {
9503 }
9504 }
9506 {
9511 }
9512 }
9514 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9515 cast (T1)X will fold away. We assume that this happens when X itself
9516 is a cast. */
9520 {
9524 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9525 when the pointed type needs higher alignment than
9526 the p+ first operand's pointed type. */
9533 /* Similarly, avoid this optimization in GENERIC for -fsanitize=null
9534 when type is a reference type and arg00's type is not,
9535 because arg00 could be validly nullptr and if arg01 doesn't return,
9536 we don't want false positive binding of reference to nullptr. */
9538 && !in_gimple_form
9545 }
9547 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9548 of the same precision, and X is an integer type not narrower than
9549 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9555 {
9561 }
9563 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9564 type of X and Y (integer types only). */
9569 {
9570 /* Be careful not to introduce new overflows. */
9571 tree mult_type;
9574 else
9578 {
9585 }
9586 }
9592 {
9599 }
9610 /* Convert fabs((double)float) into (double)fabsf(float). */
9613 {
9619 targ0));
9620 }
9624 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9643 /* Note that the operand of this must be an int
9644 and its values must be 0 or 1.
9645 ("true" is a fixed value perhaps depending on the language,
9646 but we don't handle values other than 1 correctly yet.) */
9653 /* Fold *&X to X if X is an lvalue. */
9655 {
9662 }
9668 }
9671 /* If the operation was a conversion do _not_ mark a resulting constant
9672 with TREE_OVERFLOW if the original constant was not. These conversions
9673 have implementation defined behavior and retaining the TREE_OVERFLOW
9674 flag here would confuse later passes such as VRP. */
9675 tree
9678 {
9687 }
9689 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9690 operands OP0 and OP1. LOC is the location of the resulting expression.
9691 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9692 Return the folded expression if folding is successful. Otherwise,
9693 return NULL_TREE. */
9694 static tree
9697 {
9698 tree tem;
9700 /* We only do these simplifications if we are optimizing. */
9704 /* Check for things like (A || B) && (A || C). We can convert this
9705 to A || (B && C). Note that either operator can be any of the four
9706 truth and/or operations and the transformation will still be
9707 valid. Also note that we only care about order for the
9708 ANDIF and ORIF operators. If B contains side effects, this
9709 might change the truth-value of A. */
9716 {
9736 /* This case if tricky because we must either have commutative
9737 operators or else A10 must not have side-effects. */
9743 a01);
9744 }
9746 /* See if we can build a range comparison. */
9752 {
9756 }
9760 {
9764 }
9766 /* Check for the possibility of merging component references. If our
9767 lhs is another similar operation, try to merge its rhs with our
9768 rhs. Then try to merge our lhs and rhs. */
9779 logical_op_non_short_circuit
9787 {
9794 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9795 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9796 We don't want to pack more than two leafs to a non-IF AND/OR
9797 expression.
9798 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9799 equal to IF-CODE, then we don't want to add right-hand operand.
9800 If the inner right-hand side of left-hand operand has
9801 side-effects, or isn't simple, then we can't add to it,
9802 as otherwise we might destroy if-sequence. */
9805 /* Needed for sequence points to handle trappings, and
9806 side-effects. */
9808 {
9810 arg1);
9812 tem);
9813 }
9814 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9815 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9818 /* Needed for sequence points to handle trappings, and
9819 side-effects. */
9821 {
9826 }
9827 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9828 into (A OR B).
9829 For sequence point consistancy, we need to check for trapping,
9830 and side-effects. */
9834 }
9837 }
9839 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9840 by changing CODE to reduce the magnitude of constants involved in
9841 ARG0 of the comparison.
9842 Returns a canonicalized comparison tree if a simplification was
9843 possible, otherwise returns NULL_TREE.
9844 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9845 valid if signed overflow is undefined. */
9847 static tree
9851 {
9856 /* Match A +- CST code arg1. We can change this only if overflow
9857 is undefined. */
9860 /* In principle pointers also have undefined overflow behavior,
9861 but that causes problems elsewhere. */
9868 /* Identify the constant in arg0 and its sign. */
9872 /* Overflowed constants and zero will cause problems. */
9877 /* See if we can reduce the magnitude of the constant in
9878 arg0 by changing the comparison code. */
9879 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9883 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9887 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9891 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9895 else
9899 /* Now build the constant reduced in magnitude. But not if that
9900 would produce one outside of its types range. */
9916 }
9918 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9919 overflow further. Try to decrease the magnitude of constants involved
9920 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9921 and put sole constants at the second argument position.
9922 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9924 static tree
9927 {
9928 tree t;
9933 /* Try canonicalization by simplifying arg0. */
9938 {
9942 }
9944 /* Try canonicalization by simplifying arg1 using the swapped
9945 comparison. */
9953 }
9955 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9956 space. This is used to avoid issuing overflow warnings for
9957 expressions like &p->x which cannot wrap. */
9959 static bool
9961 {
9968 poly_wide_int wi_offset;
9974 else
9979 precision);
9994 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9995 array. */
10004 }
10006 /* Return a positive integer when the symbol DECL is known to have
10007 a nonzero address, zero when it's known not to (e.g., it's a weak
10008 symbol), and a negative integer when the symbol is not yet in the
10009 symbol table and so whether or not its address is zero is unknown.
10010 For function local objects always return positive integer. */
10011 static int
10013 {
10014 /* Normally, don't do anything for variables and functions before symtab is
10015 built; it is quite possible that DECL will be declared weak later.
10016 But if folding_initializer, we need a constant answer now, so create
10017 the symtab entry and prevent later weak declaration. */
10020 = (folding_initializer
10025 /* Function local objects are never NULL. */
10033 }
10035 /* Subroutine of fold_binary. This routine performs all of the
10036 transformations that are common to the equality/inequality
10037 operators (EQ_EXPR and NE_EXPR) and the ordering operators
10038 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
10039 fold_binary should call fold_binary. Fold a comparison with
10040 tree code CODE and type TYPE with operands OP0 and OP1. Return
10041 the folded comparison or NULL_TREE. */
10043 static tree
10046 {
10056 /* For comparisons of pointers we can decompose it to a compile time
10057 comparison of the base objects and the offsets into the object.
10058 This requires at least one operand being an ADDR_EXPR or a
10059 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
10065 {
10068 machine_mode mode;
10072 /* Get base and offset for the access. Strip ADDR_EXPR for
10073 get_inner_reference, but put it back by stripping INDIRECT_REF
10074 off the base object if possible. indirect_baseN will be true
10075 if baseN is not an address but refers to the object itself. */
10078 {
10079 base0
10085 else
10087 }
10089 {
10093 {
10094 base0
10100 else
10102 }
10105 else
10109 {
10116 }
10117 }
10121 {
10122 base1
10128 else
10130 }
10132 {
10136 {
10137 base1
10143 else
10145 }
10148 else
10152 {
10159 }
10160 }
10162 /* If we have equivalent bases we might be able to simplify. */
10166 {
10167 /* We can fold this expression to a constant if the non-constant
10168 offset parts are equal. */
10172 && (equality_code
10173 || (indirect_base0
10176 {
10182 "occur when comparing P +- C1 with "
10184 WARN_STRICT_OVERFLOW_CONDITIONAL);
10187 {
10225 }
10226 }
10227 /* We can simplify the comparison to a comparison of the variable
10228 offset parts if the constant offset parts are equal.
10229 Be careful to use signed sizetype here because otherwise we
10230 mess with array offsets in the wrong way. This is possible
10231 because pointer arithmetic is restricted to retain within an
10232 object and overflow on pointer differences is undefined as of
10233 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10235 && (equality_code
10236 || (indirect_base0
10239 {
10240 /* By converting to signed sizetype we cover middle-end pointer
10241 arithmetic which operates on unsigned pointer types of size
10242 type size and ARRAY_REF offsets which are properly sign or
10243 zero extended from their type in case it is narrower than
10244 sizetype. */
10247 else
10251 else
10258 "occur when comparing P +- C1 with "
10260 WARN_STRICT_OVERFLOW_COMPARISON);
10263 }
10264 }
10265 /* For equal offsets we can simplify to a comparison of the
10266 base addresses. */
10268 && (indirect_base0
10270 && (indirect_base1
10275 {
10281 }
10282 /* Comparison between an ordinary (non-weak) symbol and a null
10283 pointer can be eliminated since such symbols must have a non
10284 null address. In C, relational expressions between pointers
10285 to objects and null pointers are undefined. The results
10286 below follow the C++ rules with the additional property that
10287 every object pointer compares greater than a null pointer.
10288 */
10291 /* Avoid folding references to struct members at offset 0 to
10292 prevent tests like '&ptr->firstmember == 0' from getting
10293 eliminated. When ptr is null, although the -> expression
10294 is strictly speaking invalid, GCC retains it as a matter
10295 of QoI. See PR c/44555. */
10298 && indirect_base0
10299 /* The caller guarantees that when one of the arguments is
10300 constant (i.e., null in this case) it is second. */
10302 {
10304 {
10315 }
10316 }
10317 }
10319 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10320 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10321 the resulting offset is smaller in absolute value than the
10322 original one and has the same sign. */
10331 {
10336 tree cst;
10338 "occur when combining constants around "
10341 /* Put the constant on the side where it doesn't overflow and is
10342 of lower absolute value and of same sign than before. */
10349 {
10352 variable1,
10356 }
10364 {
10370 variable2);
10371 }
10372 }
10378 /* If we are comparing an expression that just has comparisons
10379 of two integer values, arithmetic expressions of those comparisons,
10380 and constants, we can simplify it. There are only three cases
10381 to check: the two values can either be equal, the first can be
10382 greater, or the second can be greater. Fold the expression for
10383 those three values. Since each value must be 0 or 1, we have
10384 eight possibilities, each of which corresponds to the constant 0
10385 or 1 or one of the six possible comparisons.
10387 This handles common cases like (a > b) == 0 but also handles
10388 expressions like ((x > y) - (y > x)) > 0, which supposedly
10389 occur in macroized code. */
10392 {
10396 /* Don't handle degenerate cases here; they should already
10397 have been handled anyway. */
10406 {
10410 /* We can't just pass T to eval_subst in case cval1 or cval2
10411 was the same as ARG1. */
10413 tree high_result
10417 arg1);
10418 tree equal_result
10422 arg1);
10423 tree low_result
10427 arg1);
10429 /* All three of these results should be 0 or 1. Confirm they are.
10430 Then use those values to select the proper code to use. */
10435 {
10436 /* Make a 3-bit mask with the high-order bit being the
10437 value for `>', the next for '=', and the low for '<'. */
10441 {
10443 /* Always false. */
10464 /* Always true. */
10466 }
10469 }
10470 }
10471 }
10474 }
10477 /* Subroutine of fold_binary. Optimize complex multiplications of the
10478 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10479 argument EXPR represents the expression "z" of type TYPE. */
10481 static tree
10483 {
10488 {
10491 }
10493 {
10496 }
10497 else
10498 {
10502 }
10511 }
10514 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10515 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10516 true if successful. */
10518 static bool
10520 {
10525 {
10528 }
10530 {
10536 else
10538 }
10539 else
10545 }
10547 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10548 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10549 NULL_TREE otherwise. */
10551 tree
10553 {
10574 {
10575 HOST_WIDE_INT index;
10581 }
10584 {
10590 }
10591 else
10593 }
10595 /* Try to fold a pointer difference of type TYPE two address expressions of
10596 array references AREF0 and AREF1 using location LOC. Return a
10597 simplified expression for the difference or NULL_TREE. */
10599 static tree
10603 {
10608 /* If the bases are array references as well, recurse. If the bases
10609 are pointer indirections compute the difference of the pointers.
10610 If the bases are equal, we are set. */
10613 && (base_offset
10615 use_pointer_diff)))
10618 && (base_offset
10619 = use_pointer_diff
10629 {
10635 base_offset,
10638 }
10640 }
10642 /* If the real or vector real constant CST of type TYPE has an exact
10643 inverse, return it, else return NULL. */
10645 tree
10647 {
10648 REAL_VALUE_TYPE r;
10649 tree unit_type;
10650 machine_mode mode;
10653 {
10663 {
10667 tree_vector_builder elts;
10672 {
10677 }
10680 }
10684 }
10685 }
10687 /* Mask out the tz least significant bits of X of type TYPE where
10688 tz is the number of trailing zeroes in Y. */
10689 static wide_int
10691 {
10696 }
10698 /* Return true when T is an address and is known to be nonzero.
10699 For floating point we further ensure that T is not denormal.
10700 Similar logic is present in nonzero_address in rtlanal.h.
10702 If the return value is based on the assumption that signed overflow
10703 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10704 change *STRICT_OVERFLOW_P. */
10706 static bool
10708 {
10712 /* Doing something useful for floating point would need more work. */
10718 {
10721 strict_overflow_p);
10727 strict_overflow_p);
10735 }
10738 {
10741 strict_overflow_p);
10749 strict_overflow_p);
10763 strict_overflow_p);
10767 strict_overflow_p);
10770 {
10782 }
10786 }
10788 }
10790 /* Return true when T is an address and is known to be nonzero.
10791 Handle warnings about undefined signed overflow. */
10793 bool
10795 {
10802 "determining that expression is always "
10804 WARN_STRICT_OVERFLOW_MISC);
10806 }
10808 /* Return true if T is known not to be equal to an integer W. */
10810 bool
10812 {
10813 int_range_max vr;
10815 {
10825 else
10831 /* If T has some known zero bits and W has any of those bits set,
10832 then T is known not to be equal to W. */
10840 }
10841 }
10843 /* Fold a binary expression of code CODE and type TYPE with operands
10844 OP0 and OP1. LOC is the location of the resulting expression.
10845 Return the folded expression if folding is successful. Otherwise,
10846 return NULL_TREE. */
10848 tree
10851 {
10866 /* Strip any conversions that don't change the mode. This is
10867 safe for every expression, except for a comparison expression
10868 because its signedness is derived from its operands. So, in
10869 the latter case, only strip conversions that don't change the
10870 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10871 preserved.
10873 Note that this is done as an internal manipulation within the
10874 constant folder, in order to find the simplest representation
10875 of the arguments so that their form can be studied. In any
10876 cases, the appropriate type conversions should be put back in
10877 the tree that will get out of the constant folder. */
10880 {
10883 }
10884 else
10885 {
10888 }
10890 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10891 constant but we can't do arithmetic on them. */
10893 {
10896 {
10900 }
10901 }
10903 /* If this is a commutative operation, and ARG0 is a constant, move it
10904 to ARG1 to reduce the number of tests below. */
10909 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10910 to ARG1 to reduce the number of tests below. */
10919 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10921 First check for cases where an arithmetic operation is applied to a
10922 compound, conditional, or comparison operation. Push the arithmetic
10923 operation inside the compound or conditional to see if any folding
10924 can then be done. Convert comparison to conditional for this purpose.
10925 The also optimizes non-constant cases that used to be done in
10926 expand_expr.
10928 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10929 one of the operands is a comparison and the other is a comparison, a
10930 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10931 code below would make the expression more complex. Change it to a
10932 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10933 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10946 {
10950 boolean_type_node,
10958 }
10962 {
10964 {
10969 tem);
10970 }
10972 {
10977 tem);
10978 }
10983 {
10989 }
10994 {
11000 }
11001 }
11004 {
11006 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
11009 {
11015 }
11017 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
11020 {
11021 tree base;
11022 poly_int64 coffset;
11031 }
11036 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
11042 arg1),
11044 arg0)));
11050 {
11051 /* X + (X / CST) * -CST is X % CST. */
11056 {
11065 cst0));
11066 }
11067 }
11069 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
11070 one. Make sure the type is not saturating and has the signedness of
11071 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11072 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11079 {
11083 }
11086 {
11087 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
11088 (plus (plus (mult) (mult)) (foo)) so that we can
11089 take advantage of the factoring cases below. */
11098 {
11104 else
11117 parg0),
11119 marg)),
11123 return
11129 parg1)));
11130 }
11131 }
11132 else
11133 {
11134 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11135 to __complex__ ( x, y ). This is not the same for SNaNs or
11136 if signed zeros are involved. */
11140 {
11147 {
11151 {
11157 }
11159 {
11165 }
11166 }
11167 }
11169 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11170 We associate floats only if the user has specified
11171 -fassociative-math. */
11175 {
11180 {
11181 tree tree0;
11184 }
11185 }
11186 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11187 We associate floats only if the user has specified
11188 -fassociative-math. */
11192 {
11197 {
11198 tree tree0;
11201 }
11202 }
11203 }
11205 bit_rotate:
11206 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11207 is a rotate of A by C1 bits. */
11208 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11209 is a rotate of A by B bits.
11210 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11211 though in this case CODE must be | and not + or ^, otherwise
11212 it doesn't return A when B is 0. */
11213 {
11215 tree rtype;
11224 /* Only create rotates in complete modes. Other cases are not
11225 expanded properly. */
11228 {
11241 {
11246 }
11251 {
11254 code0 == LSHIFT_EXPR
11257 }
11259 {
11269 {
11273 orig_tree01);
11275 }
11276 }
11280 {
11291 {
11295 orig_tree01);
11297 }
11298 }
11299 }
11300 }
11302 associate:
11303 /* In most languages, can't associate operations on floats through
11304 parentheses. Rather than remember where the parentheses were, we
11305 don't associate floats at all, unless the user has specified
11306 -fassociative-math.
11307 And, we need to make sure type is not saturating. */
11311 {
11317 /* Split both trees into variables, constants, and literals. Then
11318 associate each group together, the constants with literals,
11319 then the result with variables. This increases the chances of
11320 literals being recombined later and of generating relocatable
11321 expressions for the sum of a constant and literal. */
11329 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11333 /* With undefined overflow prefer doing association in a type
11334 which wraps on overflow, if that is one of the operand types. */
11337 {
11345 }
11347 /* With undefined overflow we can only associate constants with one
11348 variable, and constants whose association doesn't overflow. */
11351 {
11353 {
11354 /* ??? If split_tree would handle NEGATE_EXPR we could
11355 simply reject these cases and the allowed cases would
11356 be the var0/minus_var1 ones. */
11362 {
11365 }
11372 {
11375 }
11381 /* The only case we can still associate with two variables
11382 is if they cancel out. */
11386 }
11392 }
11394 /* Only do something if we found more than two objects. Otherwise,
11395 nothing has changed and we risk infinite recursion. */
11403 {
11415 {
11419 }
11421 {
11425 }
11427 /* Preserve the MINUS_EXPR if the negative part of the literal is
11428 greater than the positive part. Otherwise, the multiplicative
11429 folding code (i.e extract_muldiv) may be fooled in case
11430 unsigned constants are subtracted, like in the following
11431 example: ((X*2 + 4) - 8U)/2. */
11433 {
11437 /* But avoid ending up with only negated parts. */
11439 {
11443 }
11444 else
11445 {
11449 }
11450 }
11452 /* Don't introduce overflows through reassociation. */
11457 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11464 /* Eliminate minus_con0. */
11466 {
11473 else
11476 }
11478 /* Eliminate minus_var0. */
11480 {
11484 else
11487 }
11489 return
11492 }
11493 }
11499 /* Fold &a[i] - &a[j] to i-j. */
11504 {
11508 code
11512 }
11514 /* Further transformations are not for pointers. */
11518 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11521 /* If arg0 is e.g. unsigned int and type is int, then this could
11522 introduce UB, because if A is INT_MIN at runtime, the original
11523 expression can be well defined while the latter is not.
11524 See PR83269. */
11533 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11534 __complex__ ( x, -y ). This is not the same for SNaNs or if
11535 signed zeros are involved. */
11539 {
11546 {
11550 {
11552 arg1r ? arg1r
11557 }
11559 {
11563 arg1i ? arg1i
11566 }
11567 }
11568 }
11570 /* A - B -> A + (-B) if B is easily negatable. */
11574 /* Avoid this transformation if B is a positive REAL_CST. */
11582 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11583 one. Make sure the type is not saturating and has the signedness of
11584 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11585 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11592 {
11596 }
11602 {
11603 /* Transform x * -C into -x * C if x is easily negatable. */
11618 {
11621 "occur when simplifying "
11623 WARN_STRICT_OVERFLOW_MISC);
11625 }
11627 /* Optimize z * conj(z) for integer complex numbers. */
11634 }
11635 else
11636 {
11637 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11638 This is not the same for NaNs or if signed zeros are
11639 involved. */
11645 {
11648 return
11654 return
11659 }
11661 /* Optimize z * conj(z) for floating point complex numbers.
11662 Guarded by flag_unsafe_math_optimizations as non-finite
11663 imaginary components don't produce scalar results. */
11672 }
11676 /* Canonicalize (X & C1) | C2. */
11680 {
11685 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11693 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11695 {
11698 }
11700 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11701 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11702 mode which allows further optimizations. */
11707 {
11712 {
11715 }
11716 }
11719 {
11724 }
11725 }
11727 /* See if this can be simplified into a rotate first. If that
11728 is unsuccessful continue in the association code. */
11732 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11740 /* See if this can be simplified into a rotate first. If that
11741 is unsuccessful continue in the association code. */
11745 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11750 {
11751 tree tem2;
11758 }
11759 /* Fold ~X & 1 as (X & 1) == 0. */
11763 {
11764 tree tem2;
11771 }
11772 /* Fold !X & 1 as X == 0. */
11775 {
11779 }
11781 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11782 multiple of 1 << CST. */
11784 {
11791 }
11793 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11794 bits from CST2. */
11798 {
11800 wide_int masked
11807 {
11808 /* Avoid the transform if arg1 is a mask of some
11809 mode which allows further optimizations. */
11816 }
11817 }
11819 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11822 {
11827 return
11829 }
11834 /* Don't touch a floating-point divide by zero unless the mode
11835 of the constant can represent infinity. */
11841 /* (-A) / (-B) -> A / B */
11853 /* Fall through */
11856 /* Simplify A / (B << N) where A and B are positive and B is
11857 a power of 2, to A >> (N + log2(B)). */
11862 {
11865 {
11873 WARN_STRICT_OVERFLOW_MISC);
11879 }
11880 }
11882 /* Fall through */
11890 /* Convert -A / -B to A / B when the type is signed and overflow is
11891 undefined. */
11895 {
11898 "when distributing negation across "
11900 WARN_STRICT_OVERFLOW_MISC);
11905 }
11909 {
11912 "when distributing negation across "
11914 WARN_STRICT_OVERFLOW_MISC);
11919 }
11921 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11922 operation, EXACT_DIV_EXPR.
11924 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11925 At one time others generated faster code, it's not clear if they do
11926 after the last round to changes to the DIV code in expmed.cc. */
11937 {
11941 WARN_STRICT_OVERFLOW_MISC);
11943 }
11955 {
11959 WARN_STRICT_OVERFLOW_MISC);
11961 }
11969 /* Since negative shift count is not well-defined,
11970 don't try to compute it in the compiler. */
11976 /* If we have a rotate of a bit operation with the rotate count and
11977 the second operand of the bit operation both constant,
11978 permute the two operations. */
11984 {
11992 }
11994 /* Two consecutive rotates adding up to the some integer
11995 multiple of the precision of the type can be ignored. */
12011 /* Note that the operands of this must be ints
12012 and their values must be 0 or 1.
12013 ("true" is a fixed value perhaps depending on the language.) */
12014 /* If first arg is constant zero, return it. */
12017 /* FALLTHRU */
12019 /* If either arg is constant true, drop it. */
12023 /* Preserve sequence points. */
12026 /* If second arg is constant zero, result is zero, but first arg
12027 must be evaluated. */
12030 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
12031 case will be handled here. */
12035 /* !X && X is always false. */
12039 /* X && !X is always false. */
12044 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
12045 means A >= Y && A != MAX, but in this case we know that
12046 A < X <= MAX. */
12050 {
12062 }
12071 /* Note that the operands of this must be ints
12072 and their values must be 0 or true.
12073 ("true" is a fixed value perhaps depending on the language.) */
12074 /* If first arg is constant true, return it. */
12077 /* FALLTHRU */
12079 /* If either arg is constant zero, drop it. */
12083 /* Preserve sequence points. */
12086 /* If second arg is constant true, result is true, but we must
12087 evaluate first arg. */
12090 /* Likewise for first arg, but note this only occurs here for
12091 TRUTH_OR_EXPR. */
12095 /* !X || X is always true. */
12099 /* X || !X is always true. */
12104 /* (X && !Y) || (!X && Y) is X ^ Y */
12107 {
12124 }
12133 /* If the second arg is constant zero, drop it. */
12136 /* If the second arg is constant true, this is a logical inversion. */
12138 {
12141 }
12142 /* Identical arguments cancel to zero. */
12146 /* !X ^ X is always true. */
12151 /* X ^ !X is always true. */
12167 /* bool_var != 1 becomes !bool_var. */
12174 /* bool_var == 0 becomes !bool_var. */
12181 /* !exp != 0 becomes !exp */
12186 /* If this is an EQ or NE comparison with zero and ARG0 is
12187 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12188 two operations, but the latter can be done in one less insn
12189 on machines that have only two-operand insns or on which a
12190 constant cannot be the first operand. */
12193 {
12198 {
12206 }
12209 {
12217 }
12218 }
12220 /* If this is a comparison of a field, we may be able to simplify it. */
12223 /* Handle the constant case even without -O
12224 to make sure the warnings are given. */
12226 {
12230 }
12232 /* Optimize comparisons of strlen vs zero to a compare of the
12233 first character of the string vs zero. To wit,
12234 strlen(ptr) == 0 => *ptr == 0
12235 strlen(ptr) != 0 => *ptr != 0
12236 Other cases should reduce to one of these two (or a constant)
12237 due to the return value of strlen being unsigned. */
12239 {
12247 {
12248 tree ptrtype
12250 TYPE_QUAL_CONST));
12256 }
12257 }
12259 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12260 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12264 {
12269 {
12271 {
12274 }
12277 }
12278 }
12280 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12281 (X & C) == 0 when C is a single bit. */
12286 {
12293 arg1));
12294 }
12296 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12297 constant C is a power of two, i.e. a single bit. */
12304 {
12308 }
12310 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12311 when is C is a power of two, i.e. a single bit. */
12318 {
12324 }
12328 {
12331 }
12335 {
12342 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12343 operand_equal_p guarantees no side-effects so we don't need
12344 to use omit_one_operand on Z. */
12348 arg10));
12352 arg11));
12356 arg10));
12360 arg11));
12362 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12365 {
12371 }
12372 }
12374 /* Attempt to simplify equality/inequality comparisons of complex
12375 values. Only lower the comparison if the result is known or
12376 can be simplified to a single scalar comparison. */
12381 {
12386 {
12389 }
12390 else
12391 {
12394 }
12397 {
12400 }
12401 else
12402 {
12405 }
12409 {
12411 {
12416 }
12417 else
12418 {
12423 }
12424 }
12428 {
12430 {
12435 }
12436 else
12437 {
12442 }
12443 }
12444 }
12456 /* Transform comparisons of the form X +- C CMP X. */
12461 {
12466 /* (X - c) > X becomes false. */
12472 /* Likewise (X + c) < X becomes false. */
12478 /* Convert (X - c) <= X to true. */
12485 /* Convert (X + c) >= X to true. */
12491 }
12493 /* If we are comparing an ABS_EXPR with a constant, we can
12494 convert all the cases into explicit comparisons, but they may
12495 well not be faster than doing the ABS and one comparison.
12496 But ABS (X) <= C is a range comparison, which becomes a subtraction
12497 and a comparison, and is probably faster. */
12511 /* Convert ABS_EXPR<x> >= 0 to true. */
12518 {
12521 "when simplifying comparison of "
12523 WARN_STRICT_OVERFLOW_CONDITIONAL);
12526 arg0);
12527 }
12529 /* Convert ABS_EXPR<x> < 0 to false. */
12534 {
12537 "when simplifying comparison of "
12539 WARN_STRICT_OVERFLOW_CONDITIONAL);
12542 arg0);
12543 }
12545 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12546 and similarly for >= into !=. */
12556 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12557 otherwise Y might be >= # of bits in X's type and thus e.g.
12558 (unsigned char) (1 << Y) for Y 15 might be 0.
12559 If the cast is widening, then 1 << Y should have unsigned type,
12560 otherwise if Y is number of bits in the signed shift type minus 1,
12561 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12562 31 might be 0xffffffff80000000. */
12575 {
12581 }
12593 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12594 {
12606 }
12611 /* When pedantic, a compound expression can be neither an lvalue
12612 nor an integer constant expression. */
12615 /* Don't let (0, 0) be null pointer constant. */
12623 }
12625 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12626 ((A & N) + B) & M -> (A + B) & M
12627 Similarly if (N & M) == 0,
12628 ((A | N) + B) & M -> (A + B) & M
12629 and for - instead of + (or unary - instead of +)
12630 and/or ^ instead of |.
12631 If B is constant and (B & M) == 0, fold into A & M.
12633 This function is a helper for match.pd patterns. Return non-NULL
12634 type in which the simplified operation should be performed only
12635 if any optimization is possible.
12637 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12638 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12639 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12640 +/-. */
12641 tree
12646 {
12661 wide_int cst0;
12663 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12664 arg1 (M) is == (1LL << cst) - 1.
12665 Store C into PMOP[0] and D into PMOP[1]. */
12672 {
12679 {
12682 }
12685 /* If C or D is of the form (A & N) where
12686 (N & M) == M, or of the form (A | N) or
12687 (A ^ N) where (N & M) == 0, replace it with A. */
12693 /* If C or D is a N where (N & M) == 0, it can be
12694 omitted (replaced with 0). */
12699 /* Similarly, with C - N where (-N & M) == 0. */
12707 }
12709 /* Only build anything new if we optimized one or both arguments above. */
12715 else
12717 }
12719 /* Used by contains_label_[p1]. */
12721 struct contains_label_data
12722 {
12725 };
12727 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12728 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12729 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12731 static tree
12733 {
12736 {
12747 {
12755 }
12764 }
12765 }
12767 /* Return whether the sub-tree ST contains a label which is accessible from
12768 outside the sub-tree. */
12770 static bool
12772 {
12776 }
12778 /* Fold a ternary expression of code CODE and type TYPE with operands
12779 OP0, OP1, and OP2. Return the folded expression if folding is
12780 successful. Otherwise, return NULL_TREE. */
12782 tree
12785 {
12786 tree tem;
12793 /* If this is a commutative operation, and OP0 is a constant, move it
12794 to OP1 to reduce the number of tests below. */
12803 /* Strip any conversions that don't change the mode. This is safe
12804 for every expression, except for a comparison expression because
12805 its signedness is derived from its operands. So, in the latter
12806 case, only strip conversions that don't change the signedness.
12808 Note that this is done as an internal manipulation within the
12809 constant folder, in order to find the simplest representation of
12810 the arguments so that their form can be studied. In any cases,
12811 the appropriate type conversions should be put back in the tree
12812 that will get out of the constant folder. */
12814 {
12817 }
12820 {
12823 }
12826 {
12829 }
12832 {
12836 {
12842 }
12847 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12848 so all simple results must be passed through pedantic_non_lvalue. */
12850 {
12853 /* Only optimize constant conditions when the selected branch
12854 has the same type as the COND_EXPR. This avoids optimizing
12855 away "c ? x : throw", where the throw has a void type.
12856 Avoid throwing away that operand which contains label. */
12863 }
12865 {
12872 {
12875 {
12883 }
12888 }
12889 }
12891 /* If we have A op B ? A : C, we may be able to convert this to a
12892 simpler expression, depending on the operation and the values
12893 of B and C. Signed zeros prevent all of these transformations,
12894 for reasons given above each one.
12896 Also try swapping the arguments and inverting the conditional. */
12900 {
12907 }
12912 {
12919 arg00,
12920 arg01,
12924 }
12926 /* If the second operand is simpler than the third, swap them
12927 since that produces better jump optimization results. */
12930 {
12932 /* See if this can be inverted. If it can't, possibly because
12933 it was a floating-point inequality comparison, don't do
12934 anything. */
12938 }
12940 /* Convert A ? 1 : 0 to simply A. */
12945 /* If we try to convert OP0 to our type, the
12946 call to fold will try to move the conversion inside
12947 a COND, which will recurse. In that case, the COND_EXPR
12948 is probably the best choice, so leave it alone. */
12952 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12953 over COND_EXPR in cases such as floating point comparisons. */
12962 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12967 {
12968 /* sign_bit_p looks through both zero and sign extensions,
12969 but for this optimization only sign extensions are
12970 usable. */
12973 {
12976 {
12979 }
12981 }
12982 /* sign_bit_p only checks ARG1 bits within A's precision.
12983 If <sign bit of A> has wider type than A, bits outside
12984 of A's precision in <sign bit of A> need to be checked.
12985 If they are all 0, this optimization needs to be done
12986 in unsigned A's type, if they are all 1 in signed A's type,
12987 otherwise this can't be done. */
12993 {
12995 tree tem_type;
13008 {
13011 }
13013 {
13016 }
13017 else
13019 }
13022 return
13028 arg1)));
13029 }
13031 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13032 already handled above. */
13037 {
13047 op1);
13048 }
13050 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13051 is probably obsolete because the first operand should be a
13052 truth value (that's why we have the two cases above), but let's
13053 leave it in until we can confirm this for all front-ends. */
13061 /* operand_equal_p compares just value, not precision, so e.g.
13062 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13063 second operand 32-bit -128, which is not a power of two (or vice
13064 versa. */
13068 /* Disable the transformations below for vectors, since
13069 fold_binary_op_with_conditional_arg may undo them immediately,
13070 yielding an infinite loop. */
13074 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13083 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13088 {
13090 /* Only perform transformation if ARG0 is easily inverted. */
13094 ? BIT_IOR_EXPR
13097 op1);
13098 }
13100 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13105 {
13107 /* Only perform transformation if ARG0 is easily inverted. */
13113 op2);
13114 }
13116 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13128 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13129 of fold_ternary on them. */
13139 {
13141 unsigned HOST_WIDE_INT width
13152 {
13157 {
13159 {
13164 }
13170 }
13171 }
13172 }
13174 /* On constants we can use native encode/interpret to constant
13175 fold (nearly) all BIT_FIELD_REFs. */
13181 {
13184 /* Limit us to a reasonable amount of work. To relax the
13185 other limitations we need bit-shifting of the buffer
13186 and rounding up the size. */
13190 {
13192 unsigned HOST_WIDE_INT len
13197 {
13202 }
13203 }
13204 }
13209 /* Perform constant folding of BIT_INSERT_EXPR. */
13213 {
13214 /* Build a vector of integers from the tree mask. */
13215 vec_perm_builder builder;
13219 /* Create a vec_perm_indices for the integer vector. */
13224 }
13228 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13231 {
13237 wide_int tem2
13241 }
13246 {
13248 unsigned HOST_WIDE_INT elsize
13251 {
13257 {
13263 }
13264 }
13265 }
13271 }
13273 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13274 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13275 constructor element index of the value returned. If the element is
13276 not found NULL_TREE is returned and *CTOR_IDX is updated to
13277 the index of the element after the ACCESS_INDEX position (which
13278 may be outside of the CTOR array). */
13280 tree
13283 {
13289 {
13292 {
13293 /* Static constructors for variably sized objects makes no sense. */
13296 /* ??? When it is obvious that the range is signed, treat it so. */
13301 {
13303 low_bound
13305 SIGNED);
13306 }
13307 else
13308 {
13311 }
13312 }
13313 }
13317 index_sgn);
13329 {
13330 /* Array constructor might explicitly set index, or specify a range,
13331 or leave index NULL meaning that it is next index after previous
13332 one. */
13334 {
13336 max_index = index
13338 else
13339 {
13342 index_sgn);
13343 max_index
13345 index_sgn);
13347 }
13348 }
13350 {
13356 }
13357 else
13360 /* Do we have match? */
13362 {
13364 {
13368 }
13369 }
13371 /* We're past the element we search for. Note during parsing
13372 the elements might not be sorted.
13373 ??? We should use a binary search and a flag on the
13374 CONSTRUCTOR as to whether elements are sorted in declaration
13375 order. */
13377 }
13381 }
13383 /* Perform constant folding and related simplification of EXPR.
13384 The related simplifications include x*1 => x, x*0 => 0, etc.,
13385 and application of the associative law.
13386 NOP_EXPR conversions may be removed freely (as long as we
13387 are careful not to change the type of the overall expression).
13388 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13389 but we can constant-fold them if they have constant operands. */
13391 #ifdef ENABLE_FOLD_CHECKING
13392 # define fold(x) fold_1 (x)
13394 static
13395 #endif
13396 tree
13398 {
13402 tree tem;
13405 /* Return right away if a constant. */
13409 /* CALL_EXPR-like objects with variable numbers of operands are
13410 treated specially. */
13412 {
13414 {
13417 }
13419 }
13422 {
13427 {
13445 }
13446 }
13449 {
13451 {
13458 {
13463 }
13466 }
13468 /* Return a VECTOR_CST if possible. */
13470 {
13476 tree val;
13482 }
13490 }
13492 #ifdef ENABLE_FOLD_CHECKING
13493 #undef fold
13500 /* When --enable-checking=fold, compute a digest of expr before
13501 and after actual fold call to see if fold did not accidentally
13502 change original expr. */
13504 tree
13506 {
13507 tree ret;
13527 }
13529 void
13531 {
13542 }
13544 static void
13546 {
13548 }
13550 static void
13553 {
13559 recursive_label:
13569 {
13570 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13578 }
13586 {
13587 /* Allow these fields to be modified. */
13588 tree tmp;
13599 {
13602 }
13603 }
13605 {
13606 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13607 that and change builtins.cc etc. instead - see PR89543. */
13613 }
13624 {
13627 {
13643 }
13647 {
13660 }
13677 {
13683 }
13686 {
13688 {
13691 }
13693 }
13704 {
13707 }
13717 }
13718 }
13720 /* Helper function for outputting the checksum of a tree T. When
13721 debugging with gdb, you can "define mynext" to be "next" followed
13722 by "call debug_fold_checksum (op0)", then just trace down till the
13723 outputs differ. */
13725 DEBUG_FUNCTION void
13727 {
13742 }
13744 #endif
13746 /* Fold a unary tree expression with code CODE of type TYPE with an
13747 operand OP0. LOC is the location of the resulting expression.
13748 Return a folded expression if successful. Otherwise, return a tree
13749 expression with code CODE of type TYPE with an operand OP0. */
13751 tree
13754 {
13755 tree tem;
13756 #ifdef ENABLE_FOLD_CHECKING
13765 #endif
13771 #ifdef ENABLE_FOLD_CHECKING
13778 #endif
13780 }
13782 /* Fold a binary tree expression with code CODE of type TYPE with
13783 operands OP0 and OP1. LOC is the location of the resulting
13784 expression. Return a folded expression if successful. Otherwise,
13785 return a tree expression with code CODE of type TYPE with operands
13786 OP0 and OP1. */
13788 tree
13791 MEM_STAT_DECL)
13792 {
13793 tree tem;
13794 #ifdef ENABLE_FOLD_CHECKING
13811 #endif
13817 #ifdef ENABLE_FOLD_CHECKING
13832 #endif
13834 }
13836 /* Fold a ternary tree expression with code CODE of type TYPE with
13837 operands OP0, OP1, and OP2. Return a folded expression if
13838 successful. Otherwise, return a tree expression with code CODE of
13839 type TYPE with operands OP0, OP1, and OP2. */
13841 tree
13844 {
13845 tree tem;
13846 #ifdef ENABLE_FOLD_CHECKING
13870 #endif
13877 #ifdef ENABLE_FOLD_CHECKING
13900 #endif
13902 }
13904 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13905 arguments in ARGARRAY, and a null static chain.
13906 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13907 of type TYPE from the given operands as constructed by build_call_array. */
13909 tree
13912 {
13913 tree tem;
13914 #ifdef ENABLE_FOLD_CHECKING
13933 #endif
13939 #ifdef ENABLE_FOLD_CHECKING
13955 #endif
13957 }
13959 /* Perform constant folding and related simplification of initializer
13960 expression EXPR. These behave identically to "fold_buildN" but ignore
13961 potential run-time traps and exceptions that fold must preserve. */
13963 #define START_FOLD_INIT \
13964 int saved_signaling_nans = flag_signaling_nans;\
13965 int saved_trapping_math = flag_trapping_math;\
13966 int saved_rounding_math = flag_rounding_math;\
13967 int saved_trapv = flag_trapv;\
13968 int saved_folding_initializer = folding_initializer;\
13969 flag_signaling_nans = 0;\
13970 flag_trapping_math = 0;\
13971 flag_rounding_math = 0;\
13972 flag_trapv = 0;\
13973 folding_initializer = 1;
13975 #define END_FOLD_INIT \
13976 flag_signaling_nans = saved_signaling_nans;\
13977 flag_trapping_math = saved_trapping_math;\
13978 flag_rounding_math = saved_rounding_math;\
13979 flag_trapv = saved_trapv;\
13980 folding_initializer = saved_folding_initializer;
13982 tree
13984 {
13985 tree result;
13986 START_FOLD_INIT;
13990 END_FOLD_INIT;
13992 }
13994 tree
13997 {
13998 tree result;
13999 START_FOLD_INIT;
14003 END_FOLD_INIT;
14005 }
14007 tree
14010 {
14011 tree result;
14012 START_FOLD_INIT;
14016 END_FOLD_INIT;
14018 }
14020 tree
14023 {
14024 tree result;
14025 START_FOLD_INIT;
14029 END_FOLD_INIT;
14031 }
14033 tree
14036 {
14037 tree result;
14038 START_FOLD_INIT;
14042 END_FOLD_INIT;
14044 }
14046 #undef START_FOLD_INIT
14047 #undef END_FOLD_INIT
14049 /* Determine if first argument is a multiple of second argument. Return 0 if
14050 it is not, or we cannot easily determined it to be.
14052 An example of the sort of thing we care about (at this point; this routine
14053 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14054 fold cases do now) is discovering that
14056 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14058 is a multiple of
14060 SAVE_EXPR (J * 8)
14062 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14064 This code also handles discovering that
14066 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14068 is a multiple of 8 so we don't have to worry about dealing with a
14069 possible remainder.
14071 Note that we *look* inside a SAVE_EXPR only to determine how it was
14072 calculated; it is not safe for fold to do much of anything else with the
14073 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14074 at run time. For example, the latter example above *cannot* be implemented
14075 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14076 evaluation time of the original SAVE_EXPR is not necessarily the same at
14077 the time the new expression is evaluated. The only optimization of this
14078 sort that would be valid is changing
14080 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14082 divided by 8 to
14084 SAVE_EXPR (I) * SAVE_EXPR (J)
14086 (where the same SAVE_EXPR (J) is used in the original and the
14087 transformed version).
14089 NOWRAP specifies whether all outer operations in TYPE should
14090 be considered not wrapping. Any type conversion within TOP acts
14091 as a barrier and we will fall back to NOWRAP being false.
14092 NOWRAP is mostly used to treat expressions in TYPE_SIZE and friends
14093 as not wrapping even though they are generally using unsigned arithmetic. */
14095 int
14097 {
14108 {
14110 /* Bitwise and provides a power of two multiple. If the mask is
14111 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14118 /* If the multiplication can wrap we cannot recurse further unless
14119 the bottom is a power of two which is where wrapping does not
14120 matter. */
14126 {
14132 {
14135 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14137 {
14141 {
14144 }
14145 }
14147 }
14148 }
14153 /* Handle X << CST as X * (1 << CST) and only process the constant. */
14155 {
14158 {
14159 wide_int mul_op
14163 nowrap);
14164 }
14165 }
14170 /* If the addition or subtraction can wrap we cannot recurse further
14171 unless bottom is a power of two which is where wrapping does not
14172 matter. */
14178 /* Handle cases like op0 + 0xfffffffd as op0 - 3 if the expression has
14179 unsigned type. For example, (X / 3) + 0xfffffffd is multiple of 3,
14180 but 0xfffffffd is not. */
14183 && nowrap
14188 /* It is impossible to prove if op0 +- op1 is multiple of bottom
14189 precisely, so be conservative here checking if both op0 and op1
14190 are multiple of bottom. Note we check the second operand first
14191 since it's usually simpler. */
14195 CASE_CONVERT:
14196 /* Can't handle conversions from non-integral or wider integral type. */
14201 /* NOWRAP only extends to operations in the outermost type so
14202 make sure to strip it off here. */
14217 SIGNED);
14223 {
14226 /* Check for special cases to see if top is defined as multiple
14227 of bottom:
14229 top = (X & ~(bottom - 1) ; bottom is power of 2
14231 or
14233 Y = X % bottom
14234 top = X - Y. */
14253 }
14255 /* fall through */
14263 }
14264 }
14266 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14267 This function returns true for integer expressions, and returns
14268 false if uncertain. */
14270 bool
14272 {
14277 {
14300 {
14301 CASE_CFN_FABS:
14302 CASE_CFN_FABS_FN:
14304 CASE_CFN_FMAX:
14305 CASE_CFN_FMAX_FN:
14306 CASE_CFN_FMIN:
14307 CASE_CFN_FMIN_FN:
14312 }
14316 }
14317 }
14319 /* Return true if expression X evaluates to an infinity.
14320 This function returns false for integer expressions. */
14322 bool
14324 {
14328 {
14341 }
14342 }
14344 /* Return true if expression X could evaluate to an infinity.
14345 This function returns false for integer expressions, and returns
14346 true if uncertain. */
14348 bool
14350 {
14354 {
14367 }
14368 }
14370 /* Return true if expression X evaluates to a signaling NaN.
14371 This function returns false for integer expressions. */
14373 bool
14375 {
14379 {
14390 }
14391 }
14393 /* Return true if expression X could evaluate to a signaling NaN.
14394 This function returns false for integer expressions, and returns
14395 true if uncertain. */
14397 bool
14399 {
14403 {
14423 {
14424 CASE_CFN_FABS:
14425 CASE_CFN_FABS_FN:
14427 CASE_CFN_FMAX:
14428 CASE_CFN_FMAX_FN:
14429 CASE_CFN_FMIN:
14430 CASE_CFN_FMIN_FN:
14435 }
14438 }
14439 }
14441 /* Return true if expression X evaluates to a NaN.
14442 This function returns false for integer expressions. */
14444 bool
14446 {
14450 {
14461 }
14462 }
14464 /* Return true if expression X could evaluate to a NaN.
14465 This function returns false for integer expressions, and returns
14466 true if uncertain. */
14468 bool
14470 {
14474 {
14499 {
14500 CASE_CFN_FABS:
14501 CASE_CFN_FABS_FN:
14503 CASE_CFN_FMAX:
14504 CASE_CFN_FMAX_FN:
14505 CASE_CFN_FMIN:
14506 CASE_CFN_FMIN_FN:
14511 }
14514 }
14515 }
14517 /* Return true if expression X could evaluate to -0.0.
14518 This function returns true if uncertain. */
14520 bool
14522 {
14526 {
14541 {
14542 CASE_CFN_FABS:
14543 CASE_CFN_FABS_FN:
14547 }
14550 }
14551 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14552 * but currently those predicates require tree and not const_tree. */
14554 }
14556 #define tree_expr_nonnegative_warnv_p(X, Y) \
14559 #define RECURSE(X) \
14560 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14562 /* Return true if CODE or TYPE is known to be non-negative. */
14564 static bool
14566 {
14569 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14570 have a signed:1 type (where the value is -1 and 0). */
14573 }
14575 /* Return true if (CODE OP0) is known to be non-negative. If the return
14576 value is based on the assumption that signed overflow is undefined,
14577 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14578 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14580 bool
14583 {
14588 {
14590 /* We can't return 1 if flag_wrapv is set because
14591 ABS_EXPR<INT_MIN> = INT_MIN. */
14595 {
14598 }
14606 CASE_CONVERT:
14607 {
14612 {
14616 {
14620 }
14621 }
14623 {
14629 }
14630 }
14635 }
14637 /* We don't know sign of `t', so be conservative and return false. */
14639 }
14641 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14642 value is based on the assumption that signed overflow is undefined,
14643 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14644 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14646 bool
14650 {
14655 {
14661 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14662 both unsigned and at least 2 bits shorter than the result. */
14666 {
14671 {
14675 }
14676 }
14681 {
14682 /* x * x is always non-negative for floating point x
14683 or without overflow. */
14686 {
14691 }
14692 }
14694 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14695 both unsigned and their total bits is shorter than the result. */
14699 {
14718 {
14728 }
14729 }
14736 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14737 things. */
14762 }
14764 /* We don't know sign of `t', so be conservative and return false. */
14766 }
14768 /* Return true if T is known to be non-negative. If the return
14769 value is based on the assumption that signed overflow is undefined,
14770 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14771 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14773 bool
14775 {
14780 {
14794 /* Limit the depth of recursion to avoid quadratic behavior.
14795 This is expected to catch almost all occurrences in practice.
14796 If this code misses important cases that unbounded recursion
14797 would not, passes that need this information could be revised
14798 to provide it through dataflow propagation. */
14806 }
14807 }
14809 /* Return true if T is known to be non-negative. If the return
14810 value is based on the assumption that signed overflow is undefined,
14811 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14812 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14814 bool
14817 {
14819 {
14820 CASE_CFN_ACOS:
14821 CASE_CFN_ACOS_FN:
14822 CASE_CFN_ACOSH:
14823 CASE_CFN_ACOSH_FN:
14824 CASE_CFN_CABS:
14825 CASE_CFN_CABS_FN:
14826 CASE_CFN_COSH:
14827 CASE_CFN_COSH_FN:
14828 CASE_CFN_ERFC:
14829 CASE_CFN_ERFC_FN:
14830 CASE_CFN_EXP:
14831 CASE_CFN_EXP_FN:
14832 CASE_CFN_EXP10:
14833 CASE_CFN_EXP2:
14834 CASE_CFN_EXP2_FN:
14835 CASE_CFN_FABS:
14836 CASE_CFN_FABS_FN:
14837 CASE_CFN_FDIM:
14838 CASE_CFN_FDIM_FN:
14839 CASE_CFN_HYPOT:
14840 CASE_CFN_HYPOT_FN:
14841 CASE_CFN_POW10:
14842 CASE_CFN_FFS:
14843 CASE_CFN_PARITY:
14844 CASE_CFN_POPCOUNT:
14845 CASE_CFN_CLZ:
14846 CASE_CFN_CLRSB:
14851 /* Always true. */
14854 CASE_CFN_SQRT:
14855 CASE_CFN_SQRT_FN:
14856 /* sqrt(-0.0) is -0.0. */
14861 CASE_CFN_ASINH:
14862 CASE_CFN_ASINH_FN:
14863 CASE_CFN_ATAN:
14864 CASE_CFN_ATAN_FN:
14865 CASE_CFN_ATANH:
14866 CASE_CFN_ATANH_FN:
14867 CASE_CFN_CBRT:
14868 CASE_CFN_CBRT_FN:
14869 CASE_CFN_CEIL:
14870 CASE_CFN_CEIL_FN:
14871 CASE_CFN_ERF:
14872 CASE_CFN_ERF_FN:
14873 CASE_CFN_EXPM1:
14874 CASE_CFN_EXPM1_FN:
14875 CASE_CFN_FLOOR:
14876 CASE_CFN_FLOOR_FN:
14877 CASE_CFN_FMOD:
14878 CASE_CFN_FMOD_FN:
14879 CASE_CFN_FREXP:
14880 CASE_CFN_FREXP_FN:
14881 CASE_CFN_ICEIL:
14882 CASE_CFN_IFLOOR:
14883 CASE_CFN_IRINT:
14884 CASE_CFN_IROUND:
14885 CASE_CFN_LCEIL:
14886 CASE_CFN_LDEXP:
14887 CASE_CFN_LFLOOR:
14888 CASE_CFN_LLCEIL:
14889 CASE_CFN_LLFLOOR:
14890 CASE_CFN_LLRINT:
14891 CASE_CFN_LLRINT_FN:
14892 CASE_CFN_LLROUND:
14893 CASE_CFN_LLROUND_FN:
14894 CASE_CFN_LRINT:
14895 CASE_CFN_LRINT_FN:
14896 CASE_CFN_LROUND:
14897 CASE_CFN_LROUND_FN:
14898 CASE_CFN_MODF:
14899 CASE_CFN_MODF_FN:
14900 CASE_CFN_NEARBYINT:
14901 CASE_CFN_NEARBYINT_FN:
14902 CASE_CFN_RINT:
14903 CASE_CFN_RINT_FN:
14904 CASE_CFN_ROUND:
14905 CASE_CFN_ROUND_FN:
14906 CASE_CFN_ROUNDEVEN:
14907 CASE_CFN_ROUNDEVEN_FN:
14908 CASE_CFN_SCALB:
14909 CASE_CFN_SCALBLN:
14910 CASE_CFN_SCALBLN_FN:
14911 CASE_CFN_SCALBN:
14912 CASE_CFN_SCALBN_FN:
14913 CASE_CFN_SIGNBIT:
14914 CASE_CFN_SIGNIFICAND:
14915 CASE_CFN_SINH:
14916 CASE_CFN_SINH_FN:
14917 CASE_CFN_TANH:
14918 CASE_CFN_TANH_FN:
14919 CASE_CFN_TRUNC:
14920 CASE_CFN_TRUNC_FN:
14921 /* True if the 1st argument is nonnegative. */
14924 CASE_CFN_FMAX:
14925 CASE_CFN_FMAX_FN:
14926 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14927 things. In the presence of sNaNs, we're only guaranteed to be
14928 non-negative if both operands are non-negative. In the presence
14929 of qNaNs, we're non-negative if either operand is non-negative
14930 and can't be a qNaN, or if both operands are non-negative. */
14939 CASE_CFN_FMIN:
14940 CASE_CFN_FMIN_FN:
14941 /* True if the 1st AND 2nd arguments are nonnegative. */
14944 CASE_CFN_COPYSIGN:
14945 CASE_CFN_COPYSIGN_FN:
14946 /* True if the 2nd argument is nonnegative. */
14949 CASE_CFN_POWI:
14950 /* True if the 1st argument is nonnegative or the second
14951 argument is an even integer. */
14957 CASE_CFN_POW:
14958 CASE_CFN_POW_FN:
14959 /* True if the 1st argument is nonnegative or the second
14960 argument is an even integer valued real. */
14962 {
14963 REAL_VALUE_TYPE c;
14964 HOST_WIDE_INT n;
14969 {
14970 REAL_VALUE_TYPE cint;
14974 }
14975 }
14980 }
14982 }
14984 /* Return true if T is known to be non-negative. If the return
14985 value is based on the assumption that signed overflow is undefined,
14986 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14987 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14989 static bool
14991 {
14997 {
14999 {
15003 /* If the initializer is non-void, then it's a normal expression
15004 that will be assigned to the slot. */
15008 /* Otherwise, the initializer sets the slot in some way. One common
15009 way is an assignment statement at the end of the initializer. */
15011 {
15019 else
15021 }
15027 }
15030 {
15036 arg0,
15037 arg1,
15039 }
15052 }
15053 }
15055 #undef RECURSE
15056 #undef tree_expr_nonnegative_warnv_p
15058 /* Return true if T is known to be non-negative. If the return
15059 value is based on the assumption that signed overflow is undefined,
15060 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15061 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15063 bool
15065 {
15072 {
15094 }
15097 {
15122 }
15123 }
15125 /* Return true if `t' is known to be non-negative. Handle warnings
15126 about undefined signed overflow. */
15128 bool
15130 {
15137 "determining that expression is always "
15139 WARN_STRICT_OVERFLOW_MISC);
15141 }
15144 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15145 For floating point we further ensure that T is not denormal.
15146 Similar logic is present in nonzero_address in rtlanal.h.
15148 If the return value is based on the assumption that signed overflow
15149 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15150 change *STRICT_OVERFLOW_P. */
15152 bool
15155 {
15157 {
15160 strict_overflow_p);
15163 {
15169 strict_overflow_p));
15170 }
15175 strict_overflow_p);
15179 }
15182 }
15184 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15185 For floating point we further ensure that T is not denormal.
15186 Similar logic is present in nonzero_address in rtlanal.h.
15188 If the return value is based on the assumption that signed overflow
15189 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15190 change *STRICT_OVERFLOW_P. */
15192 bool
15194 tree type,
15195 tree op0,
15197 {
15200 {
15204 {
15205 /* With the presence of negative values it is hard
15206 to say something. */
15213 /* One of operands must be positive and the other non-negative. */
15214 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15215 overflows, on a twos-complement machine the sum of two
15216 nonnegative numbers can never be zero. */
15218 strict_overflow_p)
15220 strict_overflow_p));
15221 }
15226 {
15228 strict_overflow_p)
15230 strict_overflow_p))
15231 {
15234 }
15235 }
15244 {
15247 }
15254 {
15258 /* When both operands are nonzero, then MAX must be too. */
15260 strict_overflow_p))
15263 /* MAX where operand 0 is positive is positive. */
15265 strict_overflow_p);
15266 }
15267 /* MAX where operand 1 is positive is positive. */
15272 {
15276 }
15281 strict_overflow_p)
15283 strict_overflow_p));
15287 }
15290 }
15292 /* Return true when T is an address and is known to be nonzero.
15293 For floating point we further ensure that T is not denormal.
15294 Similar logic is present in nonzero_address in rtlanal.h.
15296 If the return value is based on the assumption that signed overflow
15297 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15298 change *STRICT_OVERFLOW_P. */
15300 bool
15302 {
15305 {
15310 {
15322 /* For objects in symbol table check if we know they are non-zero.
15323 Don't do anything for variables and functions before symtab is built;
15324 it is quite possible that they will be declared weak later. */
15329 /* Constants are never weak. */
15334 }
15342 {
15346 }
15356 }
15358 }
15360 #define integer_valued_real_p(X) \
15363 #define RECURSE(X) \
15364 ((integer_valued_real_p) (X, depth + 1))
15366 /* Return true if the floating point result of (CODE OP0) has an
15367 integer value. We also allow +Inf, -Inf and NaN to be considered
15368 integer values. Return false for signaling NaN.
15370 DEPTH is the current nesting depth of the query. */
15372 bool
15374 {
15376 {
15383 CASE_CONVERT:
15384 {
15391 }
15395 }
15397 }
15399 /* Return true if the floating point result of (CODE OP0 OP1) has an
15400 integer value. We also allow +Inf, -Inf and NaN to be considered
15401 integer values. Return false for signaling NaN.
15403 DEPTH is the current nesting depth of the query. */
15405 bool
15407 {
15409 {
15419 }
15421 }
15423 /* Return true if the floating point result of calling FNDECL with arguments
15424 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15425 considered integer values. Return false for signaling NaN. If FNDECL
15426 takes fewer than 2 arguments, the remaining ARGn are null.
15428 DEPTH is the current nesting depth of the query. */
15430 bool
15432 {
15434 {
15435 CASE_CFN_CEIL:
15436 CASE_CFN_CEIL_FN:
15437 CASE_CFN_FLOOR:
15438 CASE_CFN_FLOOR_FN:
15439 CASE_CFN_NEARBYINT:
15440 CASE_CFN_NEARBYINT_FN:
15441 CASE_CFN_RINT:
15442 CASE_CFN_RINT_FN:
15443 CASE_CFN_ROUND:
15444 CASE_CFN_ROUND_FN:
15445 CASE_CFN_ROUNDEVEN:
15446 CASE_CFN_ROUNDEVEN_FN:
15447 CASE_CFN_TRUNC:
15448 CASE_CFN_TRUNC_FN:
15451 CASE_CFN_FMIN:
15452 CASE_CFN_FMIN_FN:
15453 CASE_CFN_FMAX:
15454 CASE_CFN_FMAX_FN:
15459 }
15461 }
15463 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15464 has an integer value. We also allow +Inf, -Inf and NaN to be
15465 considered integer values. Return false for signaling NaN.
15467 DEPTH is the current nesting depth of the query. */
15469 bool
15471 {
15473 {
15481 /* Limit the depth of recursion to avoid quadratic behavior.
15482 This is expected to catch almost all occurrences in practice.
15483 If this code misses important cases that unbounded recursion
15484 would not, passes that need this information could be revised
15485 to provide it through dataflow propagation. */
15489 depth));
15493 }
15495 }
15497 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15498 has an integer value. We also allow +Inf, -Inf and NaN to be
15499 considered integer values. Return false for signaling NaN.
15501 DEPTH is the current nesting depth of the query. */
15503 static bool
15505 {
15507 {
15518 }
15520 }
15522 #undef RECURSE
15523 #undef integer_valued_real_p
15525 /* Return true if the floating point expression T has an integer value.
15526 We also allow +Inf, -Inf and NaN to be considered integer values.
15527 Return false for signaling NaN.
15529 DEPTH is the current nesting depth of the query. */
15531 bool
15533 {
15541 {
15557 }
15560 {
15566 {
15575 }
15579 }
15580 }
15582 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15583 attempt to fold the expression to a constant without modifying TYPE,
15584 OP0 or OP1.
15586 If the expression could be simplified to a constant, then return
15587 the constant. If the expression would not be simplified to a
15588 constant, then return NULL_TREE. */
15590 tree
15592 {
15595 }
15597 /* Given the components of a unary expression CODE, TYPE and OP0,
15598 attempt to fold the expression to a constant without modifying
15599 TYPE or OP0.
15601 If the expression could be simplified to a constant, then return
15602 the constant. If the expression would not be simplified to a
15603 constant, then return NULL_TREE. */
15605 tree
15607 {
15610 }
15612 /* If EXP represents referencing an element in a constant string
15613 (either via pointer arithmetic or array indexing), return the
15614 tree representing the value accessed, otherwise return NULL. */
15616 tree
15618 {
15622 {
15624 tree index;
15625 tree string;
15630 else
15631 {
15635 /* Optimize the special-case of a zero lower bound.
15637 We convert the low_bound to sizetype to avoid some problems
15638 with constant folding. (E.g. suppose the lower bound is 1,
15639 and its mode is QI. Without the conversion,l (ARRAY
15640 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15641 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15647 }
15649 scalar_int_mode char_mode;
15661 }
15663 }
15665 /* Folds a read from vector element at IDX of vector ARG. */
15667 tree
15669 {
15674 {
15678 {
15685 }
15686 }
15688 }
15690 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15691 an integer constant, real, or fixed-point constant.
15693 TYPE is the type of the result. */
15695 static tree
15697 {
15701 {
15707 {
15708 FIXED_VALUE_TYPE f;
15713 /* Propagate overflow flags. */
15717 }
15721 {
15728 }
15731 }
15734 }
15736 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15737 an integer constant or real constant.
15739 TYPE is the type of the result. */
15741 tree
15743 {
15747 {
15749 {
15750 /* If the value is unsigned or non-negative, then the absolute value
15751 is the same as the ordinary value. */
15755 ;
15757 /* If the value is negative, then the absolute value is
15758 its negation. */
15759 else
15762 /* Force to the destination type, set TREE_OVERFLOW for signed
15763 TYPE only. */
15765 }
15771 else
15777 }
15780 }
15782 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15783 constant. TYPE is the type of the result. */
15785 static tree
15787 {
15791 }
15793 /* Given CODE, a relational operator, the target type, TYPE and two
15794 constant operands OP0 and OP1, return the result of the
15795 relational operation. If the result is not a compile time
15796 constant, then return NULL_TREE. */
15798 static tree
15800 {
15803 /* From here on, the only cases we handle are when the result is
15804 known to be a constant. */
15807 {
15811 /* Handle the cases where either operand is a NaN. */
15813 {
15815 {
15843 }
15846 }
15849 }
15852 {
15856 }
15858 /* Handle equality/inequality of complex constants. */
15860 {
15871 else
15873 }
15876 {
15878 {
15879 /* Have vector comparison with scalar boolean result. */
15887 {
15895 }
15897 }
15898 tree_vector_builder elts;
15903 {
15916 }
15919 }
15921 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15923 To compute GT, swap the arguments and do LT.
15924 To compute GE, do LT and invert the result.
15925 To compute LE, swap the arguments, do LT and invert the result.
15926 To compute NE, do EQ and invert the result.
15928 Therefore, the code below must handle only EQ and LT. */
15931 {
15934 }
15936 /* Note that it is safe to invert for real values here because we
15937 have already handled the one case that it matters. */
15941 {
15944 }
15946 /* Compute a result for LT or EQ if args permit;
15947 Otherwise return T. */
15949 {
15952 else
15954 }
15955 else
15961 }
15963 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15964 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15965 itself. */
15967 tree
15969 {
15970 /* If the expression does not have side effects then we don't have to wrap
15971 it with a cleanup point expression. */
15975 /* If the expression is a return, check to see if the expression inside the
15976 return has no side effects or the right hand side of the modify expression
15977 inside the return. If either don't have side effects set we don't need to
15978 wrap the expression in a cleanup point expression. Note we don't check the
15979 left hand side of the modify because it should always be a return decl. */
15981 {
15988 }
15991 }
15993 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15994 of an indirection through OP0, or NULL_TREE if no simplification is
15995 possible. */
15997 tree
15999 {
16001 tree subtype;
16002 poly_uint64 const_op01;
16011 {
16015 /* *&CONST_DECL -> to the value of the const decl. */
16018 /* *&p => p; make sure to handle *&"str"[cst] here. */
16020 {
16024 else
16026 }
16027 /* *(foo *)&fooarray => fooarray[0] */
16030 && (!in_gimple_form
16032 {
16042 }
16043 /* *(foo *)&complexfoo => __real__ complexfoo */
16047 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
16050 {
16054 index);
16055 }
16056 }
16060 {
16066 {
16067 tree op00type;
16071 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
16074 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
16075 but we want to treat offsets with MSB set as negative.
16076 For the code below negative offsets are invalid and
16077 TYPE_SIZE of the element is something unsigned, so
16078 check whether op01 fits into poly_int64, which implies
16079 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
16080 then just use poly_uint64 because we want to treat the
16081 value as unsigned. */
16083 {
16085 poly_uint64 max_offset
16089 {
16094 }
16095 }
16096 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
16099 {
16101 const_op01))
16103 }
16104 /* ((foo *)&fooarray)[1] => fooarray[1] */
16107 {
16116 {
16121 }
16122 }
16123 }
16124 }
16126 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16129 && (!in_gimple_form
16131 {
16132 tree type_domain;
16142 NULL_TREE);
16143 }
16146 }
16148 /* Builds an expression for an indirection through T, simplifying some
16149 cases. */
16151 tree
16153 {
16161 }
16163 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16165 tree
16167 {
16172 else
16174 }
16176 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16177 whose result is ignored. The type of the returned tree need not be
16178 the same as the original expression. */
16180 tree
16182 {
16188 {
16199 else
16205 {
16221 }
16226 }
16227 }
16229 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16231 tree
16233 {
16239 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16240 have to do anything. Only do this when we are not given a const,
16241 because in that case, this check is more expensive than just
16242 doing it. */
16244 {
16249 }
16251 /* If divisor is a power of two, simplify this to bit manipulation. */
16253 {
16255 {
16269 }
16270 else
16271 {
16272 tree t;
16278 }
16279 }
16280 else
16281 {
16286 }
16289 }
16291 /* Likewise, but round down. */
16293 tree
16295 {
16302 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16303 have to do anything. Only do this when we are not given a const,
16304 because in that case, this check is more expensive than just
16305 doing it. */
16307 {
16312 }
16314 /* If divisor is a power of two, simplify this to bit manipulation. */
16316 {
16317 tree t;
16321 }
16322 else
16323 {
16328 }
16331 }
16333 /* Returns the pointer to the base of the object addressed by EXP and
16334 extracts the information about the offset of the access, storing it
16335 to PBITPOS and POFFSET. */
16337 static tree
16340 {
16341 tree core;
16342 machine_mode mode;
16344 poly_int64 bitsize;
16348 {
16353 }
16355 {
16361 {
16362 poly_offset_int tem
16368 }
16369 }
16370 else
16371 {
16375 }
16378 }
16380 /* Returns true if addresses of E1 and E2 differ by a constant, false
16381 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16383 bool
16385 {
16400 {
16410 }
16412 {
16413 /* If only one of the offsets is non-constant, the difference cannot
16414 be a constant. */
16416 }
16417 else
16422 }
16424 /* Return OFF converted to a pointer offset type suitable as offset for
16425 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16426 tree
16428 {
16432 }
16434 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16435 tree
16437 {
16440 }
16442 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16443 tree
16445 {
16448 }
16450 /* Return a pointer to a NUL-terminated string containing the sequence
16451 of bytes corresponding to the representation of the object referred to
16452 by SRC (or a subsequence of such bytes within it if SRC is a reference
16453 to an initialized constant array plus some constant offset).
16454 Set *STRSIZE the number of bytes in the constant sequence including
16455 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16456 where A is the array that stores the constant sequence that SRC points
16457 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16458 need not point to a string or even an array of characters but may point
16459 to an object of any type. */
16463 {
16464 /* The offset into the array A storing the string, and A's byte size. */
16465 tree offset_node;
16466 tree mem_size;
16473 else
16480 {
16483 else
16485 }
16490 /* ARRAY_SIZE is the byte size of the array the constant sequence
16491 is stored in and equal to sizeof A. INIT_BYTES is the number
16492 of bytes in the constant sequence used to initialize the array,
16493 including any embedded NULs as well as the terminating NUL (for
16494 strings), but not including any trailing zeros/NULs past
16495 the terminating one appended implicitly to a string literal to
16496 zero out the remainder of the array it's stored in. For example,
16497 given:
16498 const char a[7] = "abc\0d";
16499 n = strlen (a + 1);
16500 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16501 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16502 is equal to strlen (A) + 1. */
16507 /* Ideally this would turn into a gcc_checking_assert over time. */
16515 {
16516 /* Compute and store the number of characters from the beginning
16517 of the substring at OFFSET to the end, including the terminating
16518 nul. Offsets past the initial length refer to null strings. */
16521 else
16523 }
16524 else
16525 {
16527 /* Support only properly NUL-terminated single byte strings. */
16532 }
16535 }
16537 /* Return a pointer to a NUL-terminated string corresponding to
16538 the expression STR referencing a constant string, possibly
16539 involving a constant offset. Return null if STR either doesn't
16540 reference a constant string or if it involves a nonconstant
16541 offset. */
16545 {
16547 }
16549 /* Given a tree T, compute which bits in T may be nonzero. */
16551 wide_int
16553 {
16555 {
16573 CASE_CONVERT:
16579 {
16584 }
16588 {
16596 }
16600 {
16608 }
16612 }
16615 }
16617 /* Helper function for address compare simplifications in match.pd.
16618 OP0 and OP1 are ADDR_EXPR operands being compared by CODE.
16619 TYPE is the type of comparison operands.
16620 BASE0, BASE1, OFF0 and OFF1 are set by the function.
16621 GENERIC is true if GENERIC folding and false for GIMPLE folding.
16622 Returns 0 if OP0 is known to be unequal to OP1 regardless of OFF{0,1},
16623 1 if bases are known to be equal and OP0 cmp OP1 depends on OFF0 cmp OFF1,
16624 and 2 if unknown. */
16626 int
16630 {
16636 {
16639 }
16641 {
16644 }
16649 /* Punt in GENERIC on variables with value expressions;
16650 the value expressions might point to fields/elements
16651 of other vars etc. */
16657 {
16661 }
16669 /* Assume different STRING_CSTs with the same content will be
16670 merged. */
16679 {
16682 /* If the offsets are equal we can ignore overflow. */
16685 /* Or if we compare using pointers to decls or strings. */
16690 }
16696 /* At this point we know (or assume) the two pointers point at
16697 different objects. */
16701 /* Punt on non-zero offsets from functions. */
16705 /* Or if the bases are neither decls nor string literals. */
16710 /* For initializers, assume addresses of different functions are
16711 different. */
16717 /* Compute whether one address points to the start of one
16718 object and another one to the end of another one. */
16721 {
16724 else
16726 }
16729 else
16730 {
16734 else
16736 }
16738 {
16741 else
16743 }
16746 else
16747 {
16751 else
16753 }
16755 {
16756 /* If one offset is pointing (or could be) to the beginning of one
16757 object and the other is pointing to one past the last byte of the
16758 other object, punt. */
16763 /* If both offsets are the same, there are some cases we know that are
16764 ok. Either if we know they aren't zero, or if we know both sizes
16765 are no zero. */
16771 }
16773 /* At this point, equal is 2 if either one or both pointers are out of
16774 bounds of their object, or one points to start of its object and the
16775 other points to end of its object. This is unspecified behavior
16776 e.g. in C++. Otherwise equal is 0. */
16780 /* When both pointers point to string literals, even when equal is 0,
16781 due to tail merging of string literals the pointers might be the same. */
16783 {
16790 /* If the bytes in the string literals starting at the pointers
16791 differ, the pointers need to be different. */
16796 {
16801 /* If even the bytes in the string literal before the
16802 pointers are the same, the string literals could be
16803 tail merged. */
16805 }
16807 }
16812 /* If this is a pointer comparison, ignore for now even
16813 valid equalities where one pointer is the offset zero
16814 of one object and the other to one past end of another one. */
16818 /* Assume that string literals can't be adjacent to variables
16819 (automatic or global). */
16823 /* Assume that automatic variables can't be adjacent to global
16824 variables. */
16829 }
16831 /* Return the single non-zero element of a CONSTRUCTOR or NULL_TREE. */
16832 tree
16834 {
16843 {
16847 }
16849 }
16851 #if CHECKING_P
16855 /* Helper functions for writing tests of folding trees. */
16857 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16859 static void
16861 tree constant)
16862 {
16864 }
16866 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16867 wrapping WRAPPED_EXPR. */
16869 static void
16871 tree wrapped_expr)
16872 {
16877 }
16879 /* Verify that various arithmetic binary operations are folded
16880 correctly. */
16882 static void
16884 {
16890 /* Addition. */
16891 /* 1 <-- (0 + 1) */
16893 one);
16895 one);
16897 /* (nonlvalue)x <-- (x + 0) */
16899 x);
16901 /* Subtraction. */
16902 /* 0 <-- (x - x) */
16904 zero);
16906 x);
16908 /* Multiplication. */
16909 /* 0 <-- (x * 0) */
16911 zero);
16913 /* (nonlvalue)x <-- (x * 1) */
16915 x);
16916 }
16918 /* Verify that various binary operations on vectors are folded
16919 correctly. */
16921 static void
16923 {
16930 /* Verify equality tests that return a scalar boolean result. */
16943 }
16945 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16947 static void
16949 {
16952 /* This will be 1 if VEC_MODE isn't a vector mode. */
16959 }
16961 /* Run all of the selftests within this file. */
16963 void
16965 {
16969 }