| blob | 57521501fff2678d7cacb44f666ac8ebde5bc104 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2023 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
89 /* Nonzero if we are folding constants inside an initializer or a C++
90 manifestly-constant-evaluated context; zero otherwise.
91 Should be used when folding in initializer enables additional
92 optimizations. */
95 /* Nonzero if we are folding C++ manifestly-constant-evaluated context; zero
96 otherwise.
97 Should be used when certain constructs shouldn't be optimized
98 during folding in that context. */
101 /* The following constants represent a bit based encoding of GCC's
102 comparison operators. This encoding simplifies transformations
103 on relational comparison operators, such as AND and OR. */
121 };
153 /* This is a helper function to detect min/max for some operands of COND_EXPR.
154 The form is "(EXP0 CMP EXP1) ? EXP2 : EXP3". */
155 tree_code
157 {
167 {
169 {
170 /* X <= Y - 1 equals to X < Y. */
173 /* X > Y - 1 equals to X >= Y. */
176 }
178 {
179 /* X < Y + 1 equals to X <= Y. */
182 /* X >= Y + 1 equals to X > Y. */
185 }
186 }
189 {
194 }
196 }
198 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
199 Otherwise, return LOC. */
201 static location_t
203 {
206 }
208 /* Similar to protected_set_expr_location, but never modify x in place,
209 if location can and needs to be set, unshare it. */
211 tree
213 {
219 {
222 }
224 }
225 \f
226 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
227 division and returns the quotient. Otherwise returns
228 NULL_TREE. */
230 tree
232 {
233 widest_int quo;
240 }
241 \f
242 /* This is nonzero if we should defer warnings about undefined
243 overflow. This facility exists because these warnings are a
244 special case. The code to estimate loop iterations does not want
245 to issue any warnings, since it works with expressions which do not
246 occur in user code. Various bits of cleanup code call fold(), but
247 only use the result if it has certain characteristics (e.g., is a
248 constant); that code only wants to issue a warning if the result is
249 used. */
253 /* If a warning about undefined overflow is deferred, this is the
254 warning. Note that this may cause us to turn two warnings into
255 one, but that is fine since it is sufficient to only give one
256 warning per expression. */
260 /* If a warning about undefined overflow is deferred, this is the
261 level at which the warning should be emitted. */
265 /* Start deferring overflow warnings. We could use a stack here to
266 permit nested calls, but at present it is not necessary. */
268 void
270 {
272 }
274 /* Stop deferring overflow warnings. If there is a pending warning,
275 and ISSUE is true, then issue the warning if appropriate. STMT is
276 the statement with which the warning should be associated (used for
277 location information); STMT may be NULL. CODE is the level of the
278 warning--a warn_strict_overflow_code value. This function will use
279 the smaller of CODE and the deferred code when deciding whether to
280 issue the warning. CODE may be zero to mean to always use the
281 deferred code. */
283 void
285 {
287 location_t locus;
292 {
298 }
309 /* Use the smallest code level when deciding to issue the
310 warning. */
319 else
322 }
324 /* Stop deferring overflow warnings, ignoring any deferred
325 warnings. */
327 void
329 {
331 }
333 /* Whether we are deferring overflow warnings. */
335 bool
337 {
339 }
341 /* This is called when we fold something based on the fact that signed
342 overflow is undefined. */
344 void
346 {
348 {
351 {
354 }
355 }
358 }
359 \f
360 /* Return true if the built-in mathematical function specified by CODE
361 is odd, i.e. -f(x) == f(-x). */
363 bool
365 {
367 {
368 CASE_CFN_ASIN:
369 CASE_CFN_ASIN_FN:
370 CASE_CFN_ASINH:
371 CASE_CFN_ASINH_FN:
372 CASE_CFN_ATAN:
373 CASE_CFN_ATAN_FN:
374 CASE_CFN_ATANH:
375 CASE_CFN_ATANH_FN:
376 CASE_CFN_CASIN:
377 CASE_CFN_CASIN_FN:
378 CASE_CFN_CASINH:
379 CASE_CFN_CASINH_FN:
380 CASE_CFN_CATAN:
381 CASE_CFN_CATAN_FN:
382 CASE_CFN_CATANH:
383 CASE_CFN_CATANH_FN:
384 CASE_CFN_CBRT:
385 CASE_CFN_CBRT_FN:
386 CASE_CFN_CPROJ:
387 CASE_CFN_CPROJ_FN:
388 CASE_CFN_CSIN:
389 CASE_CFN_CSIN_FN:
390 CASE_CFN_CSINH:
391 CASE_CFN_CSINH_FN:
392 CASE_CFN_CTAN:
393 CASE_CFN_CTAN_FN:
394 CASE_CFN_CTANH:
395 CASE_CFN_CTANH_FN:
396 CASE_CFN_ERF:
397 CASE_CFN_ERF_FN:
398 CASE_CFN_LLROUND:
399 CASE_CFN_LLROUND_FN:
400 CASE_CFN_LROUND:
401 CASE_CFN_LROUND_FN:
402 CASE_CFN_ROUND:
403 CASE_CFN_ROUNDEVEN:
404 CASE_CFN_ROUNDEVEN_FN:
405 CASE_CFN_SIN:
406 CASE_CFN_SIN_FN:
407 CASE_CFN_SINH:
408 CASE_CFN_SINH_FN:
409 CASE_CFN_TAN:
410 CASE_CFN_TAN_FN:
411 CASE_CFN_TANH:
412 CASE_CFN_TANH_FN:
413 CASE_CFN_TRUNC:
414 CASE_CFN_TRUNC_FN:
417 CASE_CFN_LLRINT:
418 CASE_CFN_LLRINT_FN:
419 CASE_CFN_LRINT:
420 CASE_CFN_LRINT_FN:
421 CASE_CFN_NEARBYINT:
422 CASE_CFN_NEARBYINT_FN:
423 CASE_CFN_RINT:
424 CASE_CFN_RINT_FN:
429 }
431 }
433 /* Check whether we may negate an integer constant T without causing
434 overflow. */
436 bool
438 {
439 tree type;
448 }
450 /* Determine whether an expression T can be cheaply negated using
451 the function negate_expr without introducing undefined overflow. */
453 static bool
455 {
456 tree type;
465 {
470 /* Check that -CST will not overflow type. */
483 /* We want to canonicalize to positive real constants. Pretend
484 that only negative ones can be easily negated. */
492 {
496 /* Steps don't prevent negation. */
503 }
518 /* -(A + B) -> (-B) - A. */
521 /* -(A + B) -> (-A) - B. */
525 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
534 /* INT_MIN/n * n doesn't overflow while negating one operand it does
535 if n is a (negative) power of two. */
546 /* Fall through. */
559 /* In general we can't negate A in A / B, because if A is INT_MIN and
560 B is not 1 we change the sign of the result. */
564 /* In general we can't negate B in A / B, because if A is INT_MIN and
565 B is 1, we may turn this into INT_MIN / -1 which is undefined
566 and actually traps on some architectures. */
575 /* Negate -((double)float) as (double)(-float). */
577 {
581 }
585 /* Negate -f(x) as f(-x). */
591 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
593 {
597 }
602 }
604 }
606 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
607 simplification is possible.
608 If negate_expr_p would return true for T, NULL_TREE will never be
609 returned. */
611 static tree
613 {
615 tree tem;
618 {
619 /* Convert - (~A) to A + 1. */
643 {
648 }
652 {
653 tree_vector_builder elts;
657 {
662 }
665 }
688 {
689 /* -(A + B) -> (-B) - A. */
691 {
695 }
697 /* -(A + B) -> (-A) - B. */
699 {
703 }
704 }
708 /* - (A - B) -> B - A */
719 /* Fall through. */
723 {
732 }
740 /* In general we can't negate A in A / B, because if A is INT_MIN and
741 B is not 1 we change the sign of the result. */
747 /* In general we can't negate B in A / B, because if A is INT_MIN and
748 B is 1, we may turn this into INT_MIN / -1 which is undefined
749 and actually traps on some architectures. */
761 /* Convert -((double)float) into (double)(-float). */
763 {
767 }
771 /* Negate -f(x) as f(-x). */
774 {
780 }
784 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
786 {
789 {
796 }
797 }
802 }
805 }
807 /* A wrapper for fold_negate_expr_1. */
809 static tree
811 {
818 }
820 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
821 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
822 return NULL_TREE. */
824 static tree
826 {
828 location_t loc;
841 }
842 \f
843 /* Split a tree IN into a constant, literal and variable parts that could be
844 combined with CODE to make IN. "constant" means an expression with
845 TREE_CONSTANT but that isn't an actual constant. CODE must be a
846 commutative arithmetic operation. Store the constant part into *CONP,
847 the literal in *LITP and return the variable part. If a part isn't
848 present, set it to null. If the tree does not decompose in this way,
849 return the entire tree as the variable part and the other parts as null.
851 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
852 case, we negate an operand that was subtracted. Except if it is a
853 literal for which we use *MINUS_LITP instead.
855 If NEGATE_P is true, we are negating all of IN, again except a literal
856 for which we use *MINUS_LITP instead. If a variable part is of pointer
857 type, it is negated after converting to TYPE. This prevents us from
858 generating illegal MINUS pointer expression. LOC is the location of
859 the converted variable part.
861 If IN is itself a literal or constant, return it as appropriate.
863 Note that we do not guarantee that any of the three values will be the
864 same type as IN, but they will have the same signedness and mode. */
866 static tree
870 {
878 /* Strip any conversions that don't change the machine mode or signedness. */
887 /* We can associate addition and subtraction together (even
888 though the C standard doesn't say so) for integers because
889 the value is not affected. For reals, the value might be
890 affected, so we can't. */
896 {
902 /* First see if either of the operands is a literal, then a constant. */
915 /* If we haven't dealt with either operand, this is not a case we can
916 decompose. Otherwise, VAR is either of the ones remaining, if any. */
921 else
924 /* Now do any needed negations. */
931 }
936 {
937 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
938 when IN is constant. */
941 }
942 else
946 {
959 }
969 }
971 /* Re-associate trees split by the above function. T1 and T2 are
972 either expressions to associate or null. Return the new
973 expression, if any. LOC is the location of the new expression. If
974 we build an operation, do it in TYPE and with CODE. */
976 static tree
978 {
980 {
983 }
987 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
988 try to fold this since we will have infinite recursion. But do
989 deal with any NEGATE_EXPRs. */
993 {
995 {
1008 }
1010 {
1013 }
1017 }
1021 }
1022 \f
1023 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1024 for use in int_const_binop, size_binop and size_diffop. */
1026 static bool
1028 {
1035 {
1044 }
1049 }
1051 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
1052 a new constant in RES. Return FALSE if we don't know how to
1053 evaluate CODE at compile-time. */
1055 bool
1059 {
1060 wide_int tmp;
1063 {
1085 /* It's unclear from the C standard whether shifts can overflow.
1086 The following code ignores overflow; perhaps a C standard
1087 interpretation ruling is needed. */
1094 {
1098 else
1100 }
1101 else
1106 else
1185 }
1187 }
1189 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1190 produce a new constant in RES. Return FALSE if we don't know how
1191 to evaluate CODE at compile-time. */
1193 static bool
1197 {
1201 {
1219 else
1226 else
1239 }
1241 }
1243 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1244 produce a new constant. Return NULL_TREE if we don't know how to
1245 evaluate CODE at compile-time. */
1247 tree
1250 {
1251 poly_wide_int poly_res;
1257 {
1263 }
1272 }
1274 /* Return true if binary operation OP distributes over addition in operand
1275 OPNO, with the other operand being held constant. OPNO counts from 1. */
1277 static bool
1279 {
1281 {
1292 }
1293 }
1295 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1296 constant. We assume ARG1 and ARG2 have the same data type, or at least
1297 are the same kind of constant and the same machine mode. Return zero if
1298 combining the constants is not allowed in the current operating mode. */
1300 static tree
1302 {
1303 /* Sanity check for the recursive cases. */
1311 {
1317 }
1320 {
1321 machine_mode mode;
1322 REAL_VALUE_TYPE d1;
1323 REAL_VALUE_TYPE d2;
1324 REAL_VALUE_TYPE value;
1325 REAL_VALUE_TYPE result;
1329 /* The following codes are handled by real_arithmetic. */
1331 {
1342 }
1350 /* Don't perform operation if we honor signaling NaNs and
1351 either operand is a signaling NaN. */
1357 /* Don't perform operation if it would raise a division
1358 by zero exception. */
1364 /* If either operand is a NaN, just return it. Otherwise, set up
1365 for floating-point trap; we return an overflow. */
1367 {
1368 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1369 is off. */
1373 }
1375 {
1376 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1377 is off. */
1381 }
1386 /* Don't constant fold this floating point operation if
1387 both operands are not NaN but the result is NaN, and
1388 flag_trapping_math. Such operations should raise an
1389 invalid operation exception. */
1397 /* Don't constant fold this floating point operation if
1398 the result has overflowed and flag_trapping_math. */
1406 /* Don't constant fold this floating point operation if the
1407 result may dependent upon the run-time rounding mode and
1408 flag_rounding_math is set, or if GCC's software emulation
1409 is unable to accurately represent the result. */
1419 }
1422 {
1423 FIXED_VALUE_TYPE f1;
1424 FIXED_VALUE_TYPE f2;
1425 FIXED_VALUE_TYPE result;
1430 /* The following codes are handled by fixed_arithmetic. */
1432 {
1444 {
1451 }
1456 }
1463 /* Propagate overflow flags. */
1467 }
1470 {
1479 {
1490 mpc_mul);
1504 mpc_div);
1505 /* Fallthru. */
1511 {
1512 /* Keep this algorithm in sync with
1513 tree-complex.cc:expand_complex_div_straight().
1515 Expand complex division to scalars, straightforward algorithm.
1516 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1517 t = br*br + bi*bi
1518 */
1519 tree magsquared
1523 tree t1
1527 tree t2
1534 }
1535 else
1536 {
1537 /* Keep this algorithm in sync with
1538 tree-complex.cc:expand_complex_div_wide().
1540 Expand complex division to scalars, modified algorithm to minimize
1541 overflow with wide input ranges. */
1547 {
1548 /* In the TRUE branch, we compute
1549 ratio = br/bi;
1550 div = (br * ratio) + bi;
1551 tr = (ar * ratio) + ai;
1552 ti = (ai * ratio) - ar;
1553 tr = tr / div;
1554 ti = ti / div; */
1565 }
1566 else
1567 {
1568 /* In the FALSE branch, we compute
1569 ratio = d/c;
1570 divisor = (d * ratio) + c;
1571 tr = (b * ratio) + a;
1572 ti = b - (a * ratio);
1573 tr = tr / div;
1574 ti = ti / div; */
1586 }
1587 }
1592 }
1596 }
1602 {
1607 /* We can operate directly on the encoding if:
1609 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1610 implies
1611 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1613 Addition and subtraction are the supported operators
1614 for which this is true. */
1617 /* We can operate directly on stepped encodings if:
1619 a3 - a2 == a2 - a1
1620 implies:
1621 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1623 which is true if (x -> x op c) distributes over addition. */
1625 else
1626 /* Similarly in reverse. */
1628 tree_vector_builder elts;
1633 {
1639 /* It is possible that const_binop cannot handle the given
1640 code and return NULL_TREE */
1644 }
1647 }
1649 /* Shifts allow a scalar offset for a vector. */
1652 {
1655 tree_vector_builder elts;
1660 {
1665 /* It is possible that const_binop cannot handle the given
1666 code and return NULL_TREE. */
1670 }
1673 }
1675 }
1677 /* Overload that adds a TYPE parameter to be able to dispatch
1678 to fold_relational_const. */
1680 tree
1682 {
1686 /* ??? Until we make the const_binop worker take the type of the
1687 result as argument put those cases that need it here. */
1689 {
1706 {
1711 }
1717 {
1733 {
1738 ? NOP_EXPR
1745 }
1748 }
1754 {
1777 {
1790 }
1793 }
1796 }
1801 /* Make sure type and arg0 have the same saturating flag. */
1806 }
1808 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1809 Return zero if computing the constants is not possible. */
1811 tree
1813 {
1814 /* Don't perform the operation, other than NEGATE and ABS, if
1815 flag_signaling_nans is on and the operand is a signaling NaN. */
1825 {
1826 CASE_CONVERT:
1833 /* If the source address is 0, and the source address space
1834 cannot have a valid object at 0, fold to dest type null. */
1845 {
1846 /* Can't call fold_negate_const directly here as that doesn't
1847 handle all cases and we might not be able to negate some
1848 constants. */
1853 }
1863 {
1867 }
1875 /* Perform BIT_NOT_EXPR on each element individually. */
1877 {
1878 tree elem;
1880 /* This can cope with stepped encodings because ~x == -1 - x. */
1881 tree_vector_builder elements;
1885 {
1891 }
1894 }
1918 {
1941 else
1946 {
1952 }
1955 }
1964 }
1967 }
1969 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1970 indicates which particular sizetype to create. */
1972 tree
1974 {
1976 }
1977 \f
1978 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1979 is a tree code. The type of the result is taken from the operands.
1980 Both must be equivalent integer types, ala int_binop_types_match_p.
1981 If the operands are constant, so is the result. */
1983 tree
1985 {
1994 /* Handle the special case of two poly_int constants faster. */
1996 {
1997 /* And some specific cases even faster than that. */
1999 {
2006 }
2008 {
2012 }
2014 {
2018 }
2020 /* Handle general case of two integer constants. For sizetype
2021 constant calculations we always want to know about overflow,
2022 even in the unsigned case. */
2026 }
2029 }
2031 /* Given two values, either both of sizetype or both of bitsizetype,
2032 compute the difference between the two values. Return the value
2033 in signed type corresponding to the type of the operands. */
2035 tree
2037 {
2039 tree ctype;
2044 /* If the type is already signed, just do the simple thing. */
2052 else
2055 /* If either operand is not a constant, do the conversions to the signed
2056 type and subtract. The hardware will do the right thing with any
2057 overflow in the subtraction. */
2063 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2064 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2065 overflow) and negate (which can't either). Special-case a result
2066 of zero while we're here. */
2072 else
2076 MINUS_EXPR,
2078 }
2079 \f
2080 /* A subroutine of fold_convert_const handling conversions of an
2081 INTEGER_CST to another integer type. */
2083 static tree
2085 {
2086 /* Given an integer constant, make new constant with new type,
2087 appropriately sign-extended or truncated. Use widest_int
2088 so that any extension is done according ARG1's type. */
2092 }
2094 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2095 to an integer type. */
2097 static tree
2099 {
2101 tree t;
2103 /* The following code implements the floating point to integer
2104 conversion rules required by the Java Language Specification,
2105 that IEEE NaNs are mapped to zero and values that overflow
2106 the target precision saturate, i.e. values greater than
2107 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2108 are mapped to INT_MIN. These semantics are allowed by the
2109 C and C++ standards that simply state that the behavior of
2110 FP-to-integer conversion is unspecified upon overflow. */
2112 wide_int val;
2113 REAL_VALUE_TYPE r;
2117 {
2124 }
2126 /* If R is NaN, return zero and show we have an overflow. */
2128 {
2131 }
2133 /* See if R is less than the lower bound or greater than the
2134 upper bound. */
2137 {
2141 {
2144 }
2145 }
2148 {
2151 {
2154 {
2157 }
2158 }
2159 }
2166 }
2168 /* A subroutine of fold_convert_const handling conversions of a
2169 FIXED_CST to an integer type. */
2171 static tree
2173 {
2174 tree t;
2176 scalar_mode mode;
2178 /* Right shift FIXED_CST to temp by fbit. */
2182 {
2184 HOST_BITS_PER_DOUBLE_INT,
2187 /* Left shift temp to temp_trunc by fbit. */
2189 HOST_BITS_PER_DOUBLE_INT,
2191 }
2192 else
2193 {
2196 }
2198 /* If FIXED_CST is negative, we need to round the value toward 0.
2199 By checking if the fractional bits are not zero to add 1 to temp. */
2205 /* Given a fixed-point constant, make new constant with new type,
2206 appropriately sign-extended or truncated. */
2214 }
2216 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2217 to another floating point type. */
2219 static tree
2221 {
2222 REAL_VALUE_TYPE value;
2223 tree t;
2225 /* If the underlying modes are the same, simply treat it as
2226 copy and rebuild with TREE_REAL_CST information and the
2227 given type. */
2229 {
2232 }
2234 /* Don't perform the operation if flag_signaling_nans is on
2235 and the operand is a signaling NaN. */
2240 /* With flag_rounding_math we should respect the current rounding mode
2241 unless the conversion is exact. */
2249 /* If converting an infinity or NAN to a representation that doesn't
2250 have one, set the overflow bit so that we can produce some kind of
2251 error message at the appropriate point if necessary. It's not the
2252 most user-friendly message, but it's better than nothing. */
2259 /* Regular overflow, conversion produced an infinity in a mode that
2260 can't represent them. */
2265 else
2268 }
2270 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2271 to a floating point type. */
2273 static tree
2275 {
2276 REAL_VALUE_TYPE value;
2277 tree t;
2285 }
2287 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2288 to another fixed-point type. */
2290 static tree
2292 {
2293 FIXED_VALUE_TYPE value;
2294 tree t;
2301 /* Propagate overflow flags. */
2305 }
2307 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2308 to a fixed-point type. */
2310 static tree
2312 {
2313 FIXED_VALUE_TYPE value;
2314 tree t;
2316 double_int di;
2323 else
2331 /* Propagate overflow flags. */
2335 }
2337 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2338 to a fixed-point type. */
2340 static tree
2342 {
2343 FIXED_VALUE_TYPE value;
2344 tree t;
2352 /* Propagate overflow flags. */
2356 }
2358 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2359 type TYPE. If no simplification can be done return NULL_TREE. */
2361 static tree
2363 {
2368 /* We can't widen types, since the runtime value could overflow the
2369 original type before being extended to the new type. */
2380 {
2387 }
2389 {
2391 {
2393 /* Avoid the folding if flag_rounding_math is on and the
2394 conversion is not exact. */
2396 {
2402 }
2404 }
2409 }
2411 {
2418 }
2420 {
2423 {
2426 /* We can't handle steps directly when extending, since the
2427 values need to wrap at the original precision first. */
2428 bool step_ok_p
2432 tree_vector_builder v;
2437 {
2443 }
2445 }
2446 }
2448 }
2450 /* Construct a vector of zero elements of vector type TYPE. */
2452 static tree
2454 {
2455 tree t;
2459 }
2461 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2463 bool
2465 {
2480 {
2502 }
2503 }
2505 /* Convert expression ARG to type TYPE. Used by the middle-end for
2506 simple conversions in preference to calling the front-end's convert. */
2508 tree
2510 {
2512 tree tem;
2523 {
2526 /* Handle conversions between pointers to different address spaces. */
2531 /* fall through */
2536 {
2540 }
2554 {
2558 }
2560 {
2564 }
2566 {
2570 }
2573 {
2591 }
2596 {
2600 }
2603 {
2617 }
2621 {
2630 integer_zero_node));
2632 {
2636 {
2642 }
2650 }
2654 }
2672 }
2673 fold_convert_exit:
2676 }
2677 \f
2678 /* Return false if expr can be assumed not to be an lvalue, true
2679 otherwise. */
2681 static bool
2683 {
2684 /* We only need to wrap lvalue tree codes. */
2686 {
2719 /* Assume the worst for front-end tree codes. */
2723 }
2726 }
2728 /* Return an expr equal to X but certainly not valid as an lvalue. */
2730 tree
2732 {
2733 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2734 us. */
2741 }
2742 \f
2743 /* Given a tree comparison code, return the code that is the logical inverse.
2744 It is generally not safe to do this for floating-point comparisons, except
2745 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2746 ERROR_MARK in this case. */
2748 enum tree_code
2750 {
2756 {
2787 }
2788 }
2790 /* Similar, but return the comparison that results if the operands are
2791 swapped. This is safe for floating-point. */
2793 enum tree_code
2795 {
2797 {
2823 }
2824 }
2827 /* Convert a comparison tree code from an enum tree_code representation
2828 into a compcode bit-based encoding. This function is the inverse of
2829 compcode_to_comparison. */
2831 static enum comparison_code
2833 {
2835 {
2866 }
2867 }
2869 /* Convert a compcode bit-based encoding of a comparison operator back
2870 to GCC's enum tree_code representation. This function is the
2871 inverse of comparison_to_compcode. */
2873 static enum tree_code
2875 {
2877 {
2908 }
2909 }
2911 /* Return true if COND1 tests the opposite condition of COND2. */
2913 bool
2915 {
2918 && (invert_tree_comparison
2925 }
2927 /* Return a tree for the comparison which is the combination of
2928 doing the AND or OR (depending on CODE) of the two operations LCODE
2929 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2930 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2931 if this makes the transformation invalid. */
2933 tree
2938 {
2945 {
2956 }
2959 {
2960 /* Eliminate unordered comparisons, as well as LTGT and ORD
2961 which are not used unless the mode has NaNs. */
2967 }
2969 {
2970 /* Check that the original operation and the optimized ones will trap
2971 under the same condition. */
2982 /* In a short-circuited boolean expression the LHS might be
2983 such that the RHS, if evaluated, will never trap. For
2984 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2985 if neither x nor y is NaN. (This is a mixed blessing: for
2986 example, the expression above will never trap, hence
2987 optimizing it to x < y would be invalid). */
2992 /* If the comparison was short-circuited, and only the RHS
2993 trapped, we may now generate a spurious trap. */
2998 /* If we changed the conditions that cause a trap, we lose. */
3001 }
3007 else
3008 {
3013 }
3014 }
3015 \f
3016 /* Return nonzero if two operands (typically of the same tree node)
3017 are necessarily equal. FLAGS modifies behavior as follows:
3019 If OEP_ONLY_CONST is set, only return nonzero for constants.
3020 This function tests whether the operands are indistinguishable;
3021 it does not test whether they are equal using C's == operation.
3022 The distinction is important for IEEE floating point, because
3023 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3024 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3026 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3027 even though it may hold multiple values during a function.
3028 This is because a GCC tree node guarantees that nothing else is
3029 executed between the evaluation of its "operands" (which may often
3030 be evaluated in arbitrary order). Hence if the operands themselves
3031 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3032 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3033 unset means assuming isochronic (or instantaneous) tree equivalence.
3034 Unless comparing arbitrary expression trees, such as from different
3035 statements, this flag can usually be left unset.
3037 If OEP_PURE_SAME is set, then pure functions with identical arguments
3038 are considered the same. It is used when the caller has other ways
3039 to ensure that global memory is unchanged in between.
3041 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
3042 not values of expressions.
3044 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
3045 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
3047 If OEP_BITWISE is set, then require the values to be bitwise identical
3048 rather than simply numerically equal. Do not take advantage of things
3049 like math-related flags or undefined behavior; only return true for
3050 values that are provably bitwise identical in all circumstances.
3052 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
3053 any operand with side effect. This is unnecesarily conservative in the
3054 case we know that arg0 and arg1 are in disjoint code paths (such as in
3055 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
3056 addresses with TREE_CONSTANT flag set so we know that &var == &var
3057 even if var is volatile. */
3059 bool
3062 {
3070 /* If either is ERROR_MARK, they aren't equal. */
3076 /* Similar, if either does not have a type (like a template id),
3077 they aren't equal. */
3081 /* Bitwise identity makes no sense if the values have different layouts. */
3086 /* We cannot consider pointers to different address space equal. */
3093 /* Check equality of integer constants before bailing out due to
3094 precision differences. */
3096 {
3097 /* Address of INTEGER_CST is not defined; check that we did not forget
3098 to drop the OEP_ADDRESS_OF flags. */
3101 }
3104 {
3105 /* If both types don't have the same signedness, then we can't consider
3106 them equal. We must check this before the STRIP_NOPS calls
3107 because they may change the signedness of the arguments. As pointers
3108 strictly don't have a signedness, require either two pointers or
3109 two non-pointers as well. */
3115 /* If both types don't have the same precision, then it is not safe
3116 to strip NOPs. */
3123 }
3124 #if 0
3125 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3126 sanity check once the issue is solved. */
3127 else
3128 /* Addresses of conversions and SSA_NAMEs (and many other things)
3129 are not defined. Check that we did not forget to drop the
3130 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3133 #endif
3135 /* In case both args are comparisons but with different comparison
3136 code, try to swap the comparison operands of one arg to produce
3137 a match and compare that variant. */
3141 {
3149 }
3152 {
3153 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3155 ;
3157 {
3158 /* If we are interested in comparing addresses ignore
3159 MEM_REF wrappings of the base that can appear just for
3160 TBAA reasons. */
3174 }
3175 else
3177 }
3179 /* When not checking adddresses, this is needed for conversions and for
3180 COMPONENT_REF. Might as well play it safe and always test this. */
3187 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3188 We don't care about side effects in that case because the SAVE_EXPR
3189 takes care of that for us. In all other cases, two expressions are
3190 equal if they have no side effects. If we have two identical
3191 expressions with side effects that should be treated the same due
3192 to the only side effects being identical SAVE_EXPR's, that will
3193 be detected in the recursive calls below.
3194 If we are taking an invariant address of two identical objects
3195 they are necessarily equal as well. */
3202 /* Next handle constant cases, those for which we can return 1 even
3203 if ONLY_CONST is set. */
3206 {
3219 {
3220 /* If we do not distinguish between signed and unsigned zero,
3221 consider them equal. */
3224 }
3228 {
3243 }
3247 flags)
3249 flags));
3260 flags | OEP_ADDRESS_OF
3263 /* In GIMPLE empty constructors are allowed in initializers of
3264 aggregates. */
3268 }
3270 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3271 two instances of undefined behavior will give identical results. */
3275 /* Define macros to test an operand from arg0 and arg1 for equality and a
3276 variant that allows null and views null as being different from any
3277 non-null value. In the latter case, if either is null, the both
3278 must be; otherwise, do the normal comparison. */
3279 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3280 TREE_OPERAND (arg1, N), flags)
3282 #define OP_SAME_WITH_NULL(N) \
3283 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3284 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3287 {
3289 /* Two conversions are equal only if signedness and modes match. */
3291 {
3292 CASE_CONVERT:
3300 }
3310 /* For commutative ops, allow the other order. */
3318 /* If either of the pointer (or reference) expressions we are
3319 dereferencing contain a side effect, these cannot be equal,
3320 but their addresses can be. */
3327 {
3330 {
3334 /* Verify that the access types are compatible. */
3338 }
3343 /* Require the same offset. */
3349 /* Fallthru. */
3357 {
3358 /* Require equal access sizes */
3364 flags)))
3366 /* Verify that access happens in similar types. */
3369 /* Verify that accesses are TBAA compatible. */
3378 /* Verify that alignment is compatible. */
3382 }
3385 /* TARGET_MEM_REF require equal extra operands. */
3396 /* Compare the array index by value if it is constant first as we
3397 may have different types but same value here. */
3403 /* Compare low bound and element size as with OEP_ADDRESS_OF
3404 we have to account for the offset of the ref. */
3409 array_ref_low_bound
3413 array_ref_element_size
3415 flags))));
3418 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3419 may be NULL when we're called to compare MEM_EXPRs. */
3422 {
3425 /* Most of time we only need to compare FIELD_DECLs for equality.
3426 However when determining address look into actual offsets.
3427 These may match for unions and unshared record types. */
3430 {
3433 {
3437 /* Non-FIELD_DECL operands can appear in C++ templates. */
3444 flags))
3446 }
3447 else
3449 }
3450 }
3461 }
3465 {
3467 /* Be sure we pass right ADDRESS_OF flag. */
3484 /* The multiplcation operands are commutative. */
3485 /* FALLTHRU */
3493 /* Otherwise take into account this is a commutative operation. */
3506 /* BIT_INSERT_EXPR has an implict operand as the type precision
3507 of op1. Need to check to make sure they are the same. */
3513 /* FALLTHRU */
3538 /* Virtual table reference. */
3550 {
3555 }
3560 }
3564 {
3568 /* If not both CALL_EXPRs are either internal or normal function
3569 functions, then they are not equal. */
3572 {
3573 /* If the CALL_EXPRs call different internal functions, then they
3574 are not equal. */
3577 }
3578 else
3579 {
3580 /* If the CALL_EXPRs call different functions, then they are not
3581 equal. */
3583 flags))
3585 }
3587 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3588 {
3592 else
3596 }
3598 /* Now see if all the arguments are the same. */
3599 {
3610 /* If we get here and both argument lists are exhausted
3611 then the CALL_EXPRs are equal. */
3613 }
3616 }
3619 /* Consider __builtin_sqrt equal to sqrt. */
3629 {
3630 /* Consider decls with the same name equal. The caller needs
3631 to make sure they refer to the same entity (such as a function
3632 formal parameter). */
3638 }
3643 {
3647 /* In GIMPLE constructors are used only to build vectors from
3648 elements. Individual elements in the constructor must be
3649 indexed in increasing order and form an initial sequence.
3651 We make no effort to compare constructors in generic.
3652 (see sem_variable::equals in ipa-icf which can do so for
3653 constants). */
3658 /* Be sure that vectors constructed have the same representation.
3659 We only tested element precision and modes to match.
3660 Vectors may be BLKmode and thus also check that the number of
3661 parts match. */
3674 {
3679 /* In GIMPLE the indexes can be either NULL or matching i.
3680 Double check this so we won't get false
3681 positives for GENERIC. */
3689 }
3691 }
3694 {
3695 /* Compare the STATEMENT_LISTs. */
3701 {
3702 /* The lists don't have the same number of statements. */
3708 flags & (OEP_LEXICOGRAPHIC
3711 }
3712 }
3717 {
3728 }
3732 }
3734 #undef OP_SAME
3735 #undef OP_SAME_WITH_NULL
3736 }
3738 /* Generate a hash value for an expression. This can be used iteratively
3739 by passing a previous result as the HSTATE argument. */
3741 void
3744 {
3750 {
3753 }
3763 {
3764 /* Alas, constants aren't shared, so we can't rely on pointer
3765 identity. */
3775 {
3779 else
3783 }
3785 {
3789 }
3799 {
3806 }
3808 /* We can just compare by pointer. */
3812 /* The node itself doesn't matter. */
3816 /* Ignore. */
3819 /* A list of expressions, for a CALL_EXPR or as the elements of a
3820 VECTOR_CST. */
3825 {
3831 {
3832 /* In GIMPLE the indexes can be either NULL or matching i. */
3837 }
3839 }
3841 {
3842 tree_stmt_iterator i;
3847 }
3856 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3857 Otherwise nodes that compare equal according to operand_equal_p might
3858 get different hash codes. However, don't do this for machine specific
3859 or front end builtins, since the function code is overloaded in those
3860 cases. */
3863 {
3866 }
3867 /* FALL THROUGH */
3870 {
3874 }
3878 {
3879 /* DECL's have a unique ID */
3881 }
3883 {
3884 /* For comparisons that can be swapped, use the lower
3885 tree code. */
3892 }
3894 {
3895 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3896 operand_equal_p. */
3900 /* Don't hash the type, that can lead to having nodes which
3901 compare equal according to operand_equal_p, but which
3902 have different hash codes. Make sure to include signedness
3903 in the hash computation. */
3906 }
3907 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3915 /* Don't ICE on FE specific trees, or their arguments etc.
3916 during operand_equal_p hash verification. */
3919 else
3920 {
3926 {
3942 {
3949 }
3963 {
3964 /* The multiplication operands are commutative. */
3971 }
3979 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3980 Usually different TARGET_EXPRs just should use
3981 different temporaries in their slots. */
3986 /* Virtual table reference. */
3994 {
3996 /* We compute mangled names only when free_lang_data is run.
3997 In that case we can hash precisely. */
4000 hstate.add_object
4001 (IDENTIFIER_HASH_VALUE
4003 }
4007 }
4009 /* Don't hash the type, that can lead to having nodes which
4010 compare equal according to operand_equal_p, but which
4011 have different hash codes. */
4013 {
4014 /* Make sure to include signness in the hash computation. */
4017 }
4020 {
4021 /* It's a commutative expression. We want to hash it the same
4022 however it appears. We do this by first hashing both operands
4023 and then rehashing based on the order of their independent
4024 hashes. */
4029 }
4030 else
4034 }
4036 }
4037 }
4039 bool
4042 {
4043 /* When checking and unless comparing DECL names, verify that if
4044 the outermost operand_equal_p call returns non-zero then ARG0
4045 and ARG1 have the same hash value. */
4047 {
4049 {
4051 {
4058 }
4060 }
4061 else
4065 }
4068 }
4073 /* Conveinece wrapper around operand_compare class because usually we do
4074 not need to play with the valueizer. */
4076 bool
4078 {
4080 }
4082 namespace inchash
4083 {
4085 /* Generate a hash value for an expression. This can be used iteratively
4086 by passing a previous result as the HSTATE argument.
4088 This function is intended to produce the same hash for expressions which
4089 would compare equal using operand_equal_p. */
4090 void
4092 {
4094 }
4096 }
4097 \f
4098 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
4099 with a different signedness or a narrower precision. */
4101 static bool
4103 {
4111 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4112 and see if the inner values are the same. This removes any
4113 signedness comparison, which doesn't matter here. */
4121 /* Discard a single widening conversion from ARG1 and see if the inner
4122 value is the same as ARG0. */
4131 }
4132 \f
4133 /* See if ARG is an expression that is either a comparison or is performing
4134 arithmetic on comparisons. The comparisons must only be comparing
4135 two different values, which will be stored in *CVAL1 and *CVAL2; if
4136 they are nonzero it means that some operands have already been found.
4137 No variables may be used anywhere else in the expression except in the
4138 comparisons.
4140 If this is true, return 1. Otherwise, return zero. */
4142 static bool
4144 {
4148 /* We can handle some of the tcc_expression cases here. */
4157 {
4176 /* First see if we can handle the first operand, then the second. For
4177 the second operand, we know *CVAL1 can't be zero. It must be that
4178 one side of the comparison is each of the values; test for the
4179 case where this isn't true by failing if the two operands
4180 are the same. */
4189 ;
4193 ;
4194 else
4198 ;
4202 ;
4203 else
4210 }
4211 }
4212 \f
4213 /* ARG is a tree that is known to contain just arithmetic operations and
4214 comparisons. Evaluate the operations in the tree substituting NEW0 for
4215 any occurrence of OLD0 as an operand of a comparison and likewise for
4216 NEW1 and OLD1. */
4218 static tree
4221 {
4226 /* We can handle some of the tcc_expression cases here. */
4234 {
4249 {
4268 }
4269 /* Fall through - ??? */
4272 {
4276 /* We need to check both for exact equality and tree equality. The
4277 former will be true if the operand has a side-effect. In that
4278 case, we know the operand occurred exactly once. */
4291 }
4295 }
4296 }
4297 \f
4298 /* Return a tree for the case when the result of an expression is RESULT
4299 converted to TYPE and OMITTED was previously an operand of the expression
4300 but is now not needed (e.g., we folded OMITTED * 0).
4302 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4303 the conversion of RESULT to TYPE. */
4305 tree
4307 {
4310 /* If the resulting operand is an empty statement, just return the omitted
4311 statement casted to void. */
4321 }
4323 /* Return a tree for the case when the result of an expression is RESULT
4324 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4325 of the expression but are now not needed.
4327 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4328 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4329 evaluated before OMITTED2. Otherwise, if neither has side effects,
4330 just do the conversion of RESULT to TYPE. */
4332 tree
4335 {
4344 }
4346 \f
4347 /* Return a simplified tree node for the truth-negation of ARG. This
4348 never alters ARG itself. We assume that ARG is an operation that
4349 returns a truth value (0 or 1).
4351 FIXME: one would think we would fold the result, but it causes
4352 problems with the dominator optimizer. */
4354 static tree
4356 {
4361 /* If this is a comparison, we can simply invert it, except for
4362 floating-point non-equality comparisons, in which case we just
4363 enclose a TRUTH_NOT_EXPR around what we have. */
4366 {
4369 && flag_trapping_math
4382 }
4385 {
4404 /* Here we can invert either operand. We invert the first operand
4405 unless the second operand is a TRUTH_NOT_EXPR in which case our
4406 result is the XOR of the first operand with the inside of the
4407 negation of the second operand. */
4412 else
4435 {
4442 /* A COND_EXPR may have a throw as one operand, which
4443 then has void type. Just leave void operands
4444 as they are. */
4450 }
4462 CASE_CONVERT:
4466 /* fall through */
4488 }
4489 }
4491 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4492 assume that ARG is an operation that returns a truth value (0 or 1
4493 for scalars, 0 or -1 for vectors). Return the folded expression if
4494 folding is successful. Otherwise, return NULL_TREE. */
4496 static tree
4498 {
4501 ? BIT_NOT_EXPR
4504 }
4506 /* Return a simplified tree node for the truth-negation of ARG. This
4507 never alters ARG itself. We assume that ARG is an operation that
4508 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4510 tree
4512 {
4518 ? BIT_NOT_EXPR
4521 }
4522 \f
4523 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4524 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4525 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4526 is the original memory reference used to preserve the alias set of
4527 the access. */
4529 static tree
4533 {
4536 /* Attempt not to lose the access path if possible. */
4538 {
4540 machine_mode nmode;
4542 tree noffset;
4550 && !reversep
4551 && !nreversep
4553 {
4556 }
4557 }
4566 {
4573 }
4588 }
4590 /* Optimize a bit-field compare.
4592 There are two cases: First is a compare against a constant and the
4593 second is a comparison of two items where the fields are at the same
4594 bit position relative to the start of a chunk (byte, halfword, word)
4595 large enough to contain it. In these cases we can avoid the shift
4596 implicit in bitfield extractions.
4598 For constants, we emit a compare of the shifted constant with the
4599 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4600 compared. For two fields at the same position, we do the ANDs with the
4601 similar mask and compare the result of the ANDs.
4603 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4604 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4605 are the left and right operands of the comparison, respectively.
4607 If the optimization described above can be done, we return the resulting
4608 tree. Otherwise we return zero. */
4610 static tree
4613 {
4617 tree unsigned_type;
4620 scalar_int_mode nmode;
4625 tree mask;
4626 tree offset;
4628 /* Get all the information about the extractions being done. If the bit size
4629 is the same as the size of the underlying object, we aren't doing an
4630 extraction at all and so can do nothing. We also don't want to
4631 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4632 then will no longer be able to replace it. */
4647 else
4648 {
4649 /* If this is not a constant, we can only do something if bit positions,
4650 sizes, signedness and storage order are the same. */
4651 rinner
4664 }
4666 /* Honor the C++ memory model and mimic what RTL expansion does. */
4670 {
4674 }
4676 /* See if we can find a mode to refer to this field. We should be able to,
4677 but fail if we can't. */
4685 /* Set signed and unsigned types of the precision of this mode for the
4686 shifts below. */
4689 /* Compute the bit position and size for the new reference and our offset
4690 within it. If the new reference is the same size as the original, we
4691 won't optimize anything, so return zero. */
4701 /* Make the mask to be used against the extracted field. */
4708 {
4712 /* If not comparing with constant, just rework the comparison
4713 and return. */
4721 }
4723 /* Otherwise, we are handling the constant case. See if the constant is too
4724 big for the field. Warn and return a tree for 0 (false) if so. We do
4725 this not only for its own sake, but to avoid having to test for this
4726 error case below. If we didn't, we might generate wrong code.
4728 For unsigned fields, the constant shifted right by the field length should
4729 be all zero. For signed fields, the high-order bits should agree with
4730 the sign bit. */
4733 {
4735 {
4739 }
4740 }
4741 else
4742 {
4745 {
4749 }
4750 }
4755 /* Single-bit compares should always be against zero. */
4757 {
4760 }
4762 /* Make a new bitfield reference, shift the constant over the
4763 appropriate number of bits and mask it with the computed mask
4764 (in case this was a signed field). If we changed it, make a new one. */
4772 mask);
4777 }
4778 \f
4779 /* Subroutine for fold_truth_andor_1: decode a field reference.
4781 If EXP is a comparison reference, we return the innermost reference.
4783 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4784 set to the starting bit number.
4786 If the innermost field can be completely contained in a mode-sized
4787 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4789 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4790 otherwise it is not changed.
4792 *PUNSIGNEDP is set to the signedness of the field.
4794 *PREVERSEP is set to the storage order of the field.
4796 *PMASK is set to the mask used. This is either contained in a
4797 BIT_AND_EXPR or derived from the width of the field.
4799 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4801 Return 0 if this is not a component reference or is one that we can't
4802 do anything with. */
4804 static tree
4809 {
4814 tree unsigned_type;
4817 /* All the optimizations using this function assume integer fields.
4818 There are problems with FP fields since the type_for_size call
4819 below can fail for, e.g., XFmode. */
4823 /* We are interested in the bare arrangement of bits, so strip everything
4824 that doesn't affect the machine mode. However, record the type of the
4825 outermost expression if it may matter below. */
4832 {
4838 }
4849 /* Reject out-of-bound accesses (PR79731). */
4861 /* If the number of bits in the reference is the same as the bitsize of
4862 the outer type, then the outer type gives the signedness. Otherwise
4863 (in case of a small bitfield) the signedness is unchanged. */
4867 /* Compute the mask to access the bitfield. */
4875 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4883 }
4885 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4886 bit positions and MASK is SIGNED. */
4888 static bool
4890 {
4894 /* If this function returns true when the type of the mask is
4895 UNSIGNED, then there will be errors. In particular see
4896 gcc.c-torture/execute/990326-1.c. There does not appear to be
4897 any documentation paper trail as to why this is so. But the pre
4898 wide-int worked with that restriction and it has been preserved
4899 here. */
4904 }
4906 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4907 represents the sign bit of EXP's type. If EXP represents a sign
4908 or zero extension, also test VAL against the unextended type.
4909 The return value is the (sub)expression whose sign bit is VAL,
4910 or NULL_TREE otherwise. */
4912 tree
4914 {
4916 tree t;
4918 /* Tree EXP must have an integral type. */
4923 /* Tree VAL must be an integer constant. */
4932 /* Handle extension from a narrower type. */
4938 }
4940 /* Subroutine for fold_truth_andor_1 and simple_condition_p: determine if an
4941 operand is simple enough to be evaluated unconditionally. */
4943 static bool
4945 {
4946 /* Strip any conversions that don't change the machine mode. */
4955 /* Don't regard global variables as simple. They may be
4956 allocated in ways unknown to the compiler (shared memory,
4957 #pragma weak, etc). */
4960 /* Weakrefs are not safe to be read, since they can be NULL.
4961 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4962 have DECL_WEAK flag set. */
4964 /* Loading a static variable is unduly expensive, but global
4965 registers aren't expensive. */
4967 }
4969 /* Determine if an operand is simple enough to be evaluated unconditionally.
4970 In addition to simple_operand_p, we assume that comparisons, conversions,
4971 and logic-not operations are simple, if their operands are simple, too. */
4973 bool
4975 {
4994 }
4996 \f
4997 /* The following functions are subroutines to fold_range_test and allow it to
4998 try to change a logical combination of comparisons into a range test.
5000 For example, both
5001 X == 2 || X == 3 || X == 4 || X == 5
5002 and
5003 X >= 2 && X <= 5
5004 are converted to
5005 (unsigned) (X - 2) <= 3
5007 We describe each set of comparisons as being either inside or outside
5008 a range, using a variable named like IN_P, and then describe the
5009 range with a lower and upper bound. If one of the bounds is omitted,
5010 it represents either the highest or lowest value of the type.
5012 In the comments below, we represent a range by two numbers in brackets
5013 preceded by a "+" to designate being inside that range, or a "-" to
5014 designate being outside that range, so the condition can be inverted by
5015 flipping the prefix. An omitted bound is represented by a "-". For
5016 example, "- [-, 10]" means being outside the range starting at the lowest
5017 possible value and ending at 10, in other words, being greater than 10.
5018 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
5019 always false.
5021 We set up things so that the missing bounds are handled in a consistent
5022 manner so neither a missing bound nor "true" and "false" need to be
5023 handled using a special case. */
5025 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
5026 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
5027 and UPPER1_P are nonzero if the respective argument is an upper bound
5028 and zero for a lower. TYPE, if nonzero, is the type of the result; it
5029 must be specified for a comparison. ARG1 will be converted to ARG0's
5030 type if both are specified. */
5032 static tree
5035 {
5036 tree tem;
5040 /* If neither arg represents infinity, do the normal operation.
5041 Else, if not a comparison, return infinity. Else handle the special
5042 comparison rules. Note that most of the cases below won't occur, but
5043 are handled for consistency. */
5046 {
5051 }
5056 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
5057 for neither. In real maths, we cannot assume open ended ranges are
5058 the same. But, this is computer arithmetic, where numbers are finite.
5059 We can therefore make the transformation of any unbounded range with
5060 the value Z, Z being greater than any representable number. This permits
5061 us to treat unbounded ranges as equal. */
5065 {
5086 }
5089 }
5090 \f
5091 /* Helper routine for make_range. Perform one step for it, return
5092 new expression if the loop should continue or NULL_TREE if it should
5093 stop. */
5095 tree
5099 {
5105 {
5107 /* We can only do something if the range is testing for zero. */
5116 /* We can only do something if the range is testing for zero
5117 and if the second operand is an integer constant. Note that
5118 saying something is "in" the range we make is done by
5119 complementing IN_P since it will set in the initial case of
5120 being not equal to zero; "out" is leaving it alone. */
5127 {
5148 }
5150 /* If this is an unsigned comparison, we also know that EXP is
5151 greater than or equal to zero. We base the range tests we make
5152 on that fact, so we record it here so we can parse existing
5153 range tests. We test arg0_type since often the return type
5154 of, e.g. EQ_EXPR, is boolean. */
5156 {
5160 NULL_TREE))
5165 /* If the high bound is missing, but we have a nonzero low
5166 bound, reverse the range so it goes from zero to the low bound
5167 minus 1. */
5169 {
5174 }
5175 }
5183 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5184 low and high are non-NULL, then normalize will DTRT. */
5187 {
5192 }
5194 /* (-x) IN [a,b] -> x in [-b, -a] */
5206 /* ~ X -> -X - 1 */
5215 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5216 move a constant to the other side. */
5221 /* If EXP is signed, any overflow in the computation is undefined,
5222 so we don't worry about it so long as our computations on
5223 the bounds don't overflow. For unsigned, overflow is defined
5224 and this is exactly the right thing. */
5236 normalize:
5237 /* Check for an unsigned range which has wrapped around the maximum
5238 value thus making n_high < n_low, and normalize it. */
5240 {
5246 /* If the range is of the form +/- [ x+1, x ], we won't
5247 be able to normalize it. But then, it represents the
5248 whole range or the empty set, so make it
5249 +/- [ -, - ]. */
5253 else
5255 }
5256 else
5264 CASE_CONVERT:
5282 /* If we're converting arg0 from an unsigned type, to exp,
5283 a signed type, we will be doing the comparison as unsigned.
5284 The tests above have already verified that LOW and HIGH
5285 are both positive.
5287 So we have to ensure that we will handle large unsigned
5288 values the same way that the current signed bounds treat
5289 negative values. */
5292 {
5293 tree high_positive;
5294 tree equiv_type;
5295 /* For fixed-point modes, we need to pass the saturating flag
5296 as the 2nd parameter. */
5298 equiv_type
5301 else
5302 equiv_type
5305 /* A range without an upper bound is, naturally, unbounded.
5306 Since convert would have cropped a very large value, use
5307 the max value for the destination type. */
5308 high_positive
5315 high_positive),
5318 /* If the low bound is specified, "and" the range with the
5319 range for which the original unsigned value will be
5320 positive. */
5322 {
5325 integer_zero_node),
5326 high_positive))
5330 }
5331 else
5332 {
5333 /* Otherwise, "or" the range with the range of the input
5334 that will be interpreted as negative. */
5337 integer_zero_node),
5338 high_positive))
5342 }
5343 }
5345 /* Otherwise, if we are converting arg0 from signed type, to exp,
5346 an unsigned type, we will do the comparison as signed. If
5347 high is non-NULL, we punt above if it doesn't fit in the signed
5348 type, so if we get through here, +[-, high] or +[low, high] are
5349 equivalent to +[-, n_high] or +[n_low, n_high]. Similarly,
5350 +[-, -] or -[-, -] are equivalent too. But if low is specified and
5351 high is not, the +[low, -] range is equivalent to union of
5352 +[n_low, -] and +[-, -1] ranges, so +[low, -] is equivalent to
5353 -[0, n_low-1] and similarly -[low, -] to +[0, n_low-1], except for
5354 low being 0, which should be treated as [-, -]. */
5357 && low
5359 {
5362 else
5363 {
5368 }
5369 }
5378 }
5379 }
5381 /* Given EXP, a logical expression, set the range it is testing into
5382 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5383 actually being tested. *PLOW and *PHIGH will be made of the same
5384 type as the returned expression. If EXP is not a comparison, we
5385 will most likely not be returning a useful value and range. Set
5386 *STRICT_OVERFLOW_P to true if the return value is only valid
5387 because signed overflow is undefined; otherwise, do not change
5388 *STRICT_OVERFLOW_P. */
5390 tree
5393 {
5401 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5402 and see if we can refine the range. Some of the cases below may not
5403 happen, but it doesn't seem worth worrying about this. We "continue"
5404 the outer loop when we've changed something; otherwise we "break"
5405 the switch, which will "break" the while. */
5411 {
5417 {
5425 }
5434 }
5436 /* If EXP is a constant, we can evaluate whether this is true or false. */
5438 {
5445 }
5449 }
5451 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5452 a bitwise check i.e. when
5453 LOW == 0xXX...X00...0
5454 HIGH == 0xXX...X11...1
5455 Return corresponding mask in MASK and stem in VALUE. */
5457 static bool
5460 {
5483 }
5484 \f
5485 /* Helper routine for build_range_check and match.pd. Return the type to
5486 perform the check or NULL if it shouldn't be optimized. */
5488 tree
5490 {
5491 /* First make sure that arithmetics in this type is valid, then make sure
5492 that it wraps around. */
5497 {
5500 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5501 for the type in question, as we rely on this here. */
5511 else
5513 }
5517 }
5519 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5520 type, TYPE, return an expression to test if EXP is in (or out of, depending
5521 on IN_P) the range. Return 0 if the test couldn't be created. */
5523 tree
5526 {
5529 /* Disable this optimization for function pointer expressions
5530 on targets that require function pointer canonicalization. */
5537 {
5543 }
5565 value);
5568 {
5570 {
5574 }
5576 }
5578 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5580 {
5584 {
5586 {
5589 etype
5591 else
5594 }
5597 }
5598 }
5600 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5601 This requires wrap-around arithmetics for the type of the expression. */
5618 }
5619 \f
5620 /* Return the predecessor of VAL in its type, handling the infinite case. */
5622 static tree
5624 {
5630 else
5633 }
5635 /* Return the successor of VAL in its type, handling the infinite case. */
5637 static tree
5639 {
5645 else
5648 }
5650 /* Given two ranges, see if we can merge them into one. Return 1 if we
5651 can, 0 if we can't. Set the output range into the specified parameters. */
5653 bool
5656 {
5660 tree tem;
5670 /* Make range 0 be the range that starts first, or ends last if they
5671 start at the same value. Swap them if it isn't. */
5674 || (lowequal
5677 {
5681 }
5683 /* If the second range is != high1 where high1 is the type maximum of
5684 the type, try first merging with < high1 range. */
5686 && high1
5693 {
5698 /* Similarly for the second range != low1 where low1 is the type minimum
5699 of the type, try first merging with > low1 range. */
5704 }
5706 /* Now flag two cases, whether the ranges are disjoint or whether the
5707 second range is totally subsumed in the first. Note that the tests
5708 below are simplified by the ones above. */
5714 /* We now have four cases, depending on whether we are including or
5715 excluding the two ranges. */
5717 {
5718 /* If they don't overlap, the result is false. If the second range
5719 is a subset it is the result. Otherwise, the range is from the start
5720 of the second to the end of the first. */
5725 else
5727 }
5730 {
5731 /* If they don't overlap, the result is the first range. If they are
5732 equal, the result is false. If the second range is a subset of the
5733 first, and the ranges begin at the same place, we go from just after
5734 the end of the second range to the end of the first. If the second
5735 range is not a subset of the first, or if it is a subset and both
5736 ranges end at the same place, the range starts at the start of the
5737 first range and ends just before the second range.
5738 Otherwise, we can't describe this as a single range. */
5744 {
5749 {
5750 /* We are in the weird situation where high0 > high1 but
5751 high1 has no successor. Punt. */
5753 }
5754 }
5756 {
5761 {
5762 /* low0 < low1 but low1 has no predecessor. Punt. */
5764 }
5765 }
5766 else
5768 }
5771 {
5772 /* If they don't overlap, the result is the second range. If the second
5773 is a subset of the first, the result is false. Otherwise,
5774 the range starts just after the first range and ends at the
5775 end of the second. */
5780 else
5781 {
5786 {
5787 /* high1 > high0 but high0 has no successor. Punt. */
5789 }
5790 }
5791 }
5793 else
5794 {
5795 /* The case where we are excluding both ranges. Here the complex case
5796 is if they don't overlap. In that case, the only time we have a
5797 range is if they are adjacent. If the second is a subset of the
5798 first, the result is the first. Otherwise, the range to exclude
5799 starts at the beginning of the first range and ends at the end of the
5800 second. */
5802 {
5807 else
5808 {
5809 /* Canonicalize - [min, x] into - [-, x]. */
5812 {
5815 GET_MODE_BITSIZE
5818 /* FALLTHROUGH */
5831 }
5833 /* Canonicalize - [x, max] into - [x, -]. */
5836 {
5839 GET_MODE_BITSIZE
5842 /* FALLTHROUGH */
5858 }
5860 /* The ranges might be also adjacent between the maximum and
5861 minimum values of the given type. For
5862 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5863 return + [x + 1, y - 1]. */
5865 {
5872 }
5873 else
5875 }
5876 }
5879 else
5881 }
5885 }
5886 \f
5888 /* Subroutine of fold, looking inside expressions of the form
5889 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5890 are the three operands of the COND_EXPR. This function is
5891 being used also to optimize A op B ? C : A, by reversing the
5892 comparison first.
5894 Return a folded expression whose code is not a COND_EXPR
5895 anymore, or NULL_TREE if no folding opportunity is found. */
5897 static tree
5901 {
5903 tree tem;
5908 /* If we have A op 0 ? A : -A, consider applying the following
5909 transformations:
5911 A == 0? A : -A same as -A
5912 A != 0? A : -A same as A
5913 A >= 0? A : -A same as abs (A)
5914 A > 0? A : -A same as abs (A)
5915 A <= 0? A : -A same as -abs (A)
5916 A < 0? A : -A same as -abs (A)
5918 None of these transformations work for modes with signed
5919 zeros. If A is +/-0, the first two transformations will
5920 change the sign of the result (from +0 to -0, or vice
5921 versa). The last four will fix the sign of the result,
5922 even though the original expressions could be positive or
5923 negative, depending on the sign of A.
5925 Note that all these transformations are correct if A is
5926 NaN, since the two alternatives (A and -A) are also NaNs. */
5933 /* In the case that A is of the form X-Y, '-A' (arg2) may
5934 have already been folded to Y-X, check for that. */
5942 {
5954 /* Fall through. */
5965 /* FALLTHRU */
5972 {
5973 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5974 is not, invokes UB both in abs and in the negation of it.
5975 So, use ABSU_EXPR instead. */
5980 }
5981 else
5982 {
5985 }
5989 }
5991 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5992 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5993 both transformations are correct when A is NaN: A != 0
5994 is then true, and A == 0 is false. */
5998 {
6003 }
6005 /* Try some transformations of A op B ? A : B.
6007 A == B? A : B same as B
6008 A != B? A : B same as A
6009 A >= B? A : B same as max (A, B)
6010 A > B? A : B same as max (B, A)
6011 A <= B? A : B same as min (A, B)
6012 A < B? A : B same as min (B, A)
6014 As above, these transformations don't work in the presence
6015 of signed zeros. For example, if A and B are zeros of
6016 opposite sign, the first two transformations will change
6017 the sign of the result. In the last four, the original
6018 expressions give different results for (A=+0, B=-0) and
6019 (A=-0, B=+0), but the transformed expressions do not.
6021 The first two transformations are correct if either A or B
6022 is a NaN. In the first transformation, the condition will
6023 be false, and B will indeed be chosen. In the case of the
6024 second transformation, the condition A != B will be true,
6025 and A will be chosen.
6027 The conversions to max() and min() are not correct if B is
6028 a number and A is not. The conditions in the original
6029 expressions will be false, so all four give B. The min()
6030 and max() versions would give a NaN instead. */
6033 /* Avoid these transformations if the COND_EXPR may be used
6034 as an lvalue in the C++ front-end. PR c++/19199. */
6035 && (in_gimple_form
6041 {
6047 {
6056 /* In C++ a ?: expression can be an lvalue, so put the
6057 operand which will be used if they are equal first
6058 so that we can convert this back to the
6059 corresponding COND_EXPR. */
6061 {
6069 }
6076 {
6084 }
6097 }
6098 }
6101 }
6104 \f
6105 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
6106 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
6107 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
6108 false) >= 2)
6109 #endif
6111 /* EXP is some logical combination of boolean tests. See if we can
6112 merge it into some range test. Return the new tree if so. */
6114 static tree
6117 {
6131 /* If op0 is known true or false and this is a short-circuiting
6132 operation we must not merge with op1 since that makes side-effects
6133 unconditional. So special-case this. */
6140 /* If this is an OR operation, invert both sides; we will invert
6141 again at the end. */
6145 /* If both expressions are the same, if we can merge the ranges, and we
6146 can build the range test, return it or it inverted. If one of the
6147 ranges is always true or always false, consider it to be the same
6148 expression as the other. */
6156 {
6160 }
6162 /* On machines where the branch cost is expensive, if this is a
6163 short-circuited branch and the underlying object on both sides
6164 is the same, make a non-short-circuit operation. */
6167 logical_op_non_short_circuit
6174 {
6175 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6176 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6177 which cases we can't do this. */
6185 {
6194 {
6197 WARN_STRICT_OVERFLOW_COMPARISON);
6201 }
6202 }
6203 }
6206 }
6207 \f
6208 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6209 bit value. Arrange things so the extra bits will be set to zero if and
6210 only if C is signed-extended to its full width. If MASK is nonzero,
6211 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6213 static tree
6215 {
6218 tree temp;
6223 /* We work by getting just the sign bit into the low-order bit, then
6224 into the high-order bit, then sign-extend. We then XOR that value
6225 with C. */
6229 /* We must use a signed type in order to get an arithmetic right shift.
6230 However, we must also avoid introducing accidental overflows, so that
6231 a subsequent call to integer_zerop will work. Hence we must
6232 do the type conversion here. At this point, the constant is either
6233 zero or one, and the conversion to a signed type can never overflow.
6234 We could get an overflow if this conversion is done anywhere else. */
6243 /* If necessary, convert the type back to match the type of C. */
6248 }
6249 \f
6250 /* For an expression that has the form
6251 (A && B) || ~B
6252 or
6253 (A || B) && ~B,
6254 we can drop one of the inner expressions and simplify to
6255 A || ~B
6256 or
6257 A && ~B
6258 LOC is the location of the resulting expression. OP is the inner
6259 logical operation; the left-hand side in the examples above, while CMPOP
6260 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6261 removing a condition that guards another, as in
6262 (A != NULL && A->...) || A == NULL
6263 which we must not transform. If RHS_ONLY is true, only eliminate the
6264 right-most operand of the inner logical operation. */
6266 static tree
6269 {
6287 {
6290 {
6293 }
6294 }
6296 {
6299 {
6302 }
6303 }
6318 }
6320 /* Find ways of folding logical expressions of LHS and RHS:
6321 Try to merge two comparisons to the same innermost item.
6322 Look for range tests like "ch >= '0' && ch <= '9'".
6323 Look for combinations of simple terms on machines with expensive branches
6324 and evaluate the RHS unconditionally.
6326 For example, if we have p->a == 2 && p->b == 4 and we can make an
6327 object large enough to span both A and B, we can do this with a comparison
6328 against the object ANDed with the a mask.
6330 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6331 operations to do this with one comparison.
6333 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6334 function and the one above.
6336 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6337 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6339 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6340 two operands.
6342 We return the simplified tree or 0 if no optimization is possible. */
6344 static tree
6347 {
6348 /* If this is the "or" of two comparisons, we can do something if
6349 the comparisons are NE_EXPR. If this is the "and", we can do something
6350 if the comparisons are EQ_EXPR. I.e.,
6351 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6353 WANTED_CODE is this operation code. For single bit fields, we can
6354 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6355 comparison for one-bit fields. */
6376 /* Start by getting the comparison codes. Fail if anything is volatile.
6377 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6378 it were surrounded with a NE_EXPR. */
6387 {
6391 }
6394 {
6398 }
6409 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6412 {
6415 {
6420 }
6423 {
6429 }
6430 }
6435 /* If the RHS can be evaluated unconditionally and its operands are
6436 simple, it wins to evaluate the RHS unconditionally on machines
6437 with expensive branches. In this case, this isn't a comparison
6438 that can be merged. */
6445 {
6446 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6457 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6467 }
6469 /* See if the comparisons can be merged. Then get all the parameters for
6470 each side. */
6495 /* It must be true that the inner operation on the lhs of each
6496 comparison must be the same if we are to be able to do anything.
6497 Then see if we have constants. If not, the same must be true for
6498 the rhs's. */
6507 {
6510 }
6515 else
6518 /* If either comparison code is not correct for our logical operation,
6519 fail. However, we can convert a one-bit comparison against zero into
6520 the opposite comparison against that bit being set in the field. */
6524 {
6526 {
6527 /* Make the left operand unsigned, since we are only interested
6528 in the value of one bit. Otherwise we are doing the wrong
6529 thing below. */
6532 }
6533 else
6535 }
6537 /* This is analogous to the code for l_const above. */
6539 {
6541 {
6544 }
6545 else
6547 }
6549 /* See if we can find a mode that contains both fields being compared on
6550 the left. If we can't, fail. Otherwise, update all constants and masks
6551 to be relative to a field of that size. */
6565 {
6568 }
6578 {
6587 {
6591 }
6592 }
6594 {
6603 {
6607 }
6608 }
6610 /* If the right sides are not constant, do the same for it. Also,
6611 disallow this optimization if a size, signedness or storage order
6612 mismatch occurs between the left and right sides. */
6614 {
6618 /* Make sure the two fields on the right
6619 correspond to the left without being swapped. */
6636 {
6639 }
6650 /* Make a mask that corresponds to both fields being compared.
6651 Do this for both items being compared. If the operands are the
6652 same size and the bits being compared are in the same position
6653 then we can do this by masking both and comparing the masked
6654 results. */
6661 {
6675 }
6677 /* There is still another way we can do something: If both pairs of
6678 fields being compared are adjacent, we may be able to make a wider
6679 field containing them both.
6681 Note that we still must mask the lhs/rhs expressions. Furthermore,
6682 the mask must be shifted to account for the shift done by
6683 make_bit_field_ref. */
6692 {
6693 tree type;
6711 /* Convert to the smaller type before masking out unwanted bits. */
6714 {
6716 {
6720 }
6722 {
6726 }
6727 }
6736 }
6739 }
6741 /* Handle the case of comparisons with constants. If there is something in
6742 common between the masks, those bits of the constants must be the same.
6743 If not, the condition is always false. Test for this to avoid generating
6744 incorrect code below. */
6749 {
6751 {
6754 }
6755 else
6756 {
6759 }
6760 }
6765 /* Construct the expression we will return. First get the component
6766 reference we will make. Unless the mask is all ones the width of
6767 that field, perform the mask operation. Then compare with the
6768 merged constant. */
6779 }
6780 \f
6781 /* T is an integer expression that is being multiplied, divided, or taken a
6782 modulus (CODE says which and what kind of divide or modulus) by a
6783 constant C. See if we can eliminate that operation by folding it with
6784 other operations already in T. WIDE_TYPE, if non-null, is a type that
6785 should be used for the computation if wider than our type.
6787 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6788 (X * 2) + (Y * 4). We must, however, be assured that either the original
6789 expression would not overflow or that overflow is undefined for the type
6790 in the language in question.
6792 If we return a non-null expression, it is an equivalent form of the
6793 original computation, but need not be in the original type.
6795 We set *STRICT_OVERFLOW_P to true if the return values depends on
6796 signed overflow being undefined. Otherwise we do not change
6797 *STRICT_OVERFLOW_P. */
6799 static tree
6802 {
6803 /* To avoid exponential search depth, refuse to allow recursion past
6804 three levels. Beyond that (1) it's highly unlikely that we'll find
6805 something interesting and (2) we've probably processed it before
6806 when we built the inner expression. */
6809 tree ret;
6814 depth++;
6816 depth--;
6819 }
6821 static tree
6824 {
6836 /* Don't deal with constants of zero here; they confuse the code below. */
6846 /* Note that we need not handle conditional operations here since fold
6847 already handles those cases. So just do arithmetic here. */
6849 {
6851 /* For a constant, we can always simplify if we are a multiply
6852 or (for divide and modulus) if it is a multiple of our constant. */
6856 {
6859 /* If the multiplication overflowed, we lost information on it.
6860 See PR68142 and PR69845. */
6864 }
6870 /* If op0 is an expression ... */
6876 /* ... and has wrapping overflow, and its type is smaller
6877 than ctype, then we cannot pass through as widening. */
6881 /* ... or this is a truncation (t is narrower than op0),
6882 then we cannot pass through this narrowing. */
6885 /* ... or signedness changes for division or modulus,
6886 then we cannot pass through this conversion. */
6890 /* ... or has undefined overflow while the converted to
6891 type has not, we cannot do the operation in the inner type
6892 as that would introduce undefined overflow. */
6897 /* Pass the constant down and see if we can make a simplification. If
6898 we can, replace this expression with the inner simplification for
6899 possible later conversion to our or some other type. */
6910 /* If widening the type changes it from signed to unsigned, then we
6911 must avoid building ABS_EXPR itself as unsigned. */
6913 {
6917 {
6920 }
6922 }
6923 /* If the constant is negative, we cannot simplify this. */
6926 /* FALLTHROUGH */
6928 /* For division and modulus, type can't be unsigned, as e.g.
6929 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6930 For signed types, even with wrapping overflow, this is fine. */
6939 /* If widening the type changes the signedness, then we can't perform
6940 this optimization as that changes the result. */
6944 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6950 {
6957 }
6961 /* If the second operand is constant, this is a multiplication
6962 or floor division, by a power of two, so we can treat it that
6963 way unless the multiplier or divisor overflows. Signed
6964 left-shift overflow is implementation-defined rather than
6965 undefined in C90, so do not convert signed left shift into
6966 multiplication. */
6969 /* const_binop may not detect overflow correctly,
6970 so check for it explicitly here. */
6979 ctype,
6981 t1),
6986 /* See if we can eliminate the operation on both sides. If we can, we
6987 can return a new PLUS or MINUS. If we can't, the only remaining
6988 cases where we can do anything are if the second operand is a
6989 constant. */
6996 /* If not multiplication, we can only do this if both operands
6997 are divisible by c. */
7000 {
7005 }
7007 /* If this was a subtraction, negate OP1 and set it to be an addition.
7008 This simplifies the logic below. */
7010 {
7012 /* If OP1 was not easily negatable, the constant may be OP0. */
7014 {
7017 }
7018 }
7023 /* If either OP1 or C are negative, this optimization is not safe for
7024 some of the division and remainder types while for others we need
7025 to change the code. */
7027 {
7035 }
7037 /* If it's a multiply or a division/modulus operation of a multiple
7038 of our constant, do the operation and verify it doesn't overflow. */
7042 {
7045 /* We allow the constant to overflow with wrapping semantics. */
7049 }
7050 else
7053 /* If we have an unsigned type, we cannot widen the operation since it
7054 will change the result if the original computation overflowed. */
7058 /* The last case is if we are a multiply. In that case, we can
7059 apply the distributive law to commute the multiply and addition
7060 if the multiplication of the constants doesn't overflow
7061 and overflow is defined. With undefined overflow
7062 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
7063 But fold_plusminus_mult_expr would factor back any power-of-two
7064 value so do not distribute in the first place in this case. */
7072 op1);
7077 /* We have a special case here if we are doing something like
7078 (C * 8) % 4 since we know that's zero. */
7081 /* If the multiplication can overflow we cannot optimize this. */
7086 {
7089 }
7091 /* ... fall through ... */
7095 /* If we can extract our operation from the LHS, do so and return a
7096 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
7097 do something only if the second operand is a constant. */
7113 /* If these are the same operation types, we can associate them
7114 assuming no overflow. */
7116 {
7131 }
7133 /* If these operations "cancel" each other, we have the main
7134 optimizations of this pass, which occur when either constant is a
7135 multiple of the other, in which case we replace this with either an
7136 operation or CODE or TCODE.
7138 If we have an unsigned type, we cannot do this since it will change
7139 the result if the original computation overflowed. */
7147 {
7150 {
7156 }
7159 {
7165 }
7166 }
7171 }
7174 }
7175 \f
7176 /* Return a node which has the indicated constant VALUE (either 0 or
7177 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7178 and is of the indicated TYPE. */
7180 tree
7182 {
7191 else
7193 }
7196 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7197 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7198 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7199 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7200 COND is the first argument to CODE; otherwise (as in the example
7201 given here), it is the second argument. TYPE is the type of the
7202 original expression. Return NULL_TREE if no simplification is
7203 possible. */
7205 static tree
7210 {
7218 /* Do not move possibly trapping operations into the conditional as this
7219 pessimizes code and causes gimplification issues when applied late. */
7227 {
7231 /* If this operand throws an expression, then it does not make
7232 sense to try to perform a logical or arithmetic operation
7233 involving it. */
7238 }
7241 {
7246 }
7247 else
7248 /* Detect the case of mixing vector and scalar types - bail out. */
7254 /* This transformation is only worthwhile if we don't have to wrap ARG
7255 in a SAVE_EXPR and the operation can be simplified without recursing
7256 on at least one of the branches once its pushed inside the COND_EXPR. */
7265 {
7269 else
7271 }
7273 {
7277 else
7279 }
7281 /* Check that we have simplified at least one of the branches. */
7286 }
7288 \f
7289 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7291 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7292 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7293 if ARG - ZERO_ARG is the same as X.
7295 If ARG is NULL, check for any value of type TYPE.
7297 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7298 and finite. The problematic cases are when X is zero, and its mode
7299 has signed zeros. In the case of rounding towards -infinity,
7300 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7301 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7303 bool
7306 {
7310 /* Don't allow the fold with -fsignaling-nans. */
7314 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7318 /* There is no case that is safe for all rounding modes. */
7322 /* In a vector or complex, we would need to check the sign of all zeros. */
7328 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7332 /* The mode has signed zeros, and we have to honor their sign.
7333 In this situation, there are only two cases we can return true for.
7334 (i) X - 0 is the same as X with default rounding.
7335 (ii) X + 0 is X when X can't possibly be -0.0. */
7337 }
7339 /* Subroutine of match.pd that optimizes comparisons of a division by
7340 a nonzero integer constant against an integer constant, i.e.
7341 X/C1 op C2.
7343 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7344 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7346 enum tree_code
7349 {
7354 /* We have to do this the hard way to detect unsigned overflow.
7355 prod = int_const_binop (MULT_EXPR, c1, c2); */
7361 {
7365 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7368 }
7370 {
7373 {
7392 }
7393 }
7394 else
7395 {
7396 /* A negative divisor reverses the relational operators. */
7401 {
7420 }
7421 }
7434 }
7436 /* Test whether it is preferable to swap two operands, ARG0 and
7437 ARG1, for example because ARG0 is an integer constant and ARG1
7438 isn't. */
7440 bool
7442 {
7456 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7457 for commutative and comparison operators. Ensuring a canonical
7458 form allows the optimizers to find additional redundancies without
7459 having to explicitly check for both orderings. */
7465 /* Put SSA_NAMEs last. */
7471 /* Put variables last. */
7478 }
7481 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7482 means A >= Y && A != MAX, but in this case we know that
7483 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7485 static tree
7487 {
7494 else
7503 {
7506 }
7508 {
7511 }
7512 else
7519 {
7520 /* Convert the pointer types into integer before taking the difference. */
7524 }
7525 else
7532 }
7534 /* Fold a sum or difference of at least one multiplication.
7535 Returns the folded tree or NULL if no simplification could be made. */
7537 static tree
7540 {
7544 /* (A * C) +- (B * C) -> (A+-B) * C.
7545 (A * C) +- A -> A * (C+-1).
7546 We are most concerned about the case where C is a constant,
7547 but other combinations show up during loop reduction. Since
7548 it is not difficult, try all four possibilities. */
7551 {
7554 }
7556 {
7559 }
7560 else
7561 {
7562 /* We cannot generate constant 1 for fract. */
7567 }
7569 {
7572 }
7574 {
7576 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7577 the purpose of this canonicalization. */
7581 {
7584 }
7585 else
7587 }
7588 else
7589 {
7590 /* We cannot generate constant 1 for fract. */
7595 }
7598 /* Prefer factoring a common non-constant. */
7608 /* No identical multiplicands; see if we can find a common
7609 power-of-two factor in non-power-of-two multiplies. This
7610 can help in multi-dimensional array access. */
7612 {
7615 HOST_WIDE_INT tmp;
7617 tree maybe_same;
7619 /* Move min of absolute values to int11. */
7621 {
7626 }
7627 else
7634 /* The remainder should not be a constant, otherwise we
7635 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7636 increased the number of multiplications necessary. */
7638 {
7646 }
7647 }
7654 /* We are neither factoring zero nor minus one. */
7662 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7663 same may be minus one and thus the multiplication may overflow. Perform
7664 the sum operation in an unsigned type. */
7669 /* If the sum evaluated to a constant that is not -INF the multiplication
7670 cannot overflow. */
7677 /* Do not resort to unsigned multiplication because
7678 we lose the no-overflow property of the expression. */
7680 }
7682 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7683 specified by EXPR into the buffer PTR of length LEN bytes.
7684 Return the number of bytes placed in the buffer, or zero
7685 upon failure. */
7687 static int
7689 {
7701 /* Dry run. */
7707 {
7709 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7710 number of bytes. */
7714 {
7721 else
7723 }
7724 else
7728 }
7730 }
7733 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7734 specified by EXPR into the buffer PTR of length LEN bytes.
7735 Return the number of bytes placed in the buffer, or zero
7736 upon failure. */
7738 static int
7740 {
7744 FIXED_VALUE_TYPE value;
7759 }
7762 /* Subroutine of native_encode_expr. Encode the REAL_CST
7763 specified by EXPR into the buffer PTR of length LEN bytes.
7764 Return the number of bytes placed in the buffer, or zero
7765 upon failure. */
7767 static int
7769 {
7775 /* There are always 32 bits in each long, no matter the size of
7776 the hosts long. We handle floating point representations with
7777 up to 192 bits. */
7786 /* Dry run. */
7795 {
7800 {
7807 else
7809 }
7810 else
7811 {
7814 {
7815 /* Reverse bytes within each long, or within the entire float
7816 if it's smaller than a long (for HFmode). */
7819 }
7820 }
7825 }
7827 }
7829 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7830 specified by EXPR into the buffer PTR of length LEN bytes.
7831 Return the number of bytes placed in the buffer, or zero
7832 upon failure. */
7834 static int
7836 {
7838 tree part;
7852 }
7854 /* Like native_encode_vector, but only encode the first COUNT elements.
7855 The other arguments are as for native_encode_vector. */
7857 static int
7860 {
7864 {
7865 /* This is the only case in which elements can be smaller than a byte.
7866 Element 0 is always in the lsb of the containing byte. */
7875 /* Zero the buffer and then set bits later where necessary. */
7884 {
7890 {
7893 }
7894 }
7896 }
7901 {
7903 {
7906 }
7917 }
7919 }
7921 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7922 specified by EXPR into the buffer PTR of length LEN bytes.
7923 Return the number of bytes placed in the buffer, or zero
7924 upon failure. */
7926 static int
7928 {
7933 }
7936 /* Subroutine of native_encode_expr. Encode the STRING_CST
7937 specified by EXPR into the buffer PTR of length LEN bytes.
7938 Return the number of bytes placed in the buffer, or zero
7939 upon failure. */
7941 static int
7943 {
7946 /* Wide-char strings are encoded in target byte-order so native
7947 encoding them is trivial. */
7962 else
7963 {
7966 {
7969 }
7971 }
7973 }
7976 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
7977 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
7978 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
7979 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
7980 sufficient to encode the entire EXPR, or if OFF is out of bounds.
7981 Otherwise, start at byte offset OFF and encode at most LEN bytes.
7982 Return the number of bytes placed in the buffer, or zero upon failure. */
7984 int
7986 {
7987 /* We don't support starting at negative offset and -1 is special. */
7992 {
8013 }
8014 }
8016 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
8017 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
8018 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
8019 machine modes, we can't just use build_nonstandard_integer_type. */
8021 tree
8023 {
8024 machine_mode mode;
8026 {
8033 {
8037 }
8038 }
8044 {
8052 }
8055 }
8057 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8058 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8059 to be non-NULL and OFF zero), then in addition to filling the
8060 bytes pointed by PTR with the value also clear any bits pointed
8061 by MASK that are known to be initialized, keep them as is for
8062 e.g. uninitialized padding bits or uninitialized fields. */
8064 int
8067 {
8070 /* We don't support starting at negative offset and -1 is special. */
8078 {
8082 mask);
8097 {
8098 tree min_index;
8116 {
8121 {
8124 }
8129 else
8133 {
8137 offset_int wpos
8145 offset_int wcount
8152 }
8154 {
8157 offset_int wpos
8165 }
8168 {
8170 {
8181 }
8183 {
8187 }
8188 }
8192 do
8193 {
8198 {
8200 {
8203 fieldsize);
8206 }
8208 ptr
8211 fieldsize,
8214 mask
8218 else
8219 {
8222 }
8223 }
8226 {
8227 /* Partial overlap. */
8233 {
8237 fieldsize);
8238 }
8239 else
8240 {
8244 }
8247 }
8249 }
8251 }
8253 }
8256 {
8266 {
8272 {
8275 }
8278 {
8287 }
8291 else
8295 {
8296 tree fld;
8298 {
8311 }
8313 {
8317 }
8320 {
8321 cnt--;
8327 }
8328 }
8333 {
8346 {
8351 }
8352 }
8353 else
8354 {
8359 }
8363 /* Prepare to deal with integral bit-fields and filter out other
8364 bit-fields that do not start and end on a byte boundary. */
8366 {
8371 {
8377 }
8383 }
8393 {
8394 /* FIXME: Handle PDP endian. */
8405 {
8408 }
8409 else
8410 {
8418 else
8419 {
8422 }
8423 }
8433 else
8446 /* If the bitfield does not start at byte boundary, handle
8447 the partial byte at the start. */
8450 {
8452 {
8457 {
8460 else
8462 }
8463 }
8464 else
8465 {
8470 {
8473 else
8477 }
8478 }
8479 }
8480 /* If the bitfield does not end at byte boundary, handle
8481 the partial byte at the end. */
8485 {
8487 {
8494 }
8495 else
8496 {
8503 }
8504 }
8508 {
8513 }
8514 else
8515 {
8516 /* Partial overlap. */
8520 {
8523 }
8527 }
8529 }
8534 {
8537 {
8540 {
8544 }
8547 }
8550 fldsize,
8560 }
8561 else
8562 {
8563 /* Partial overlap. */
8569 {
8573 fieldsize);
8574 }
8575 else
8576 {
8580 }
8583 }
8584 }
8586 }
8588 }
8589 }
8592 /* Subroutine of native_interpret_expr. Interpret the contents of
8593 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8594 If the buffer cannot be interpreted, return NULL_TREE. */
8596 static tree
8598 {
8608 }
8611 /* Subroutine of native_interpret_expr. Interpret the contents of
8612 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8613 If the buffer cannot be interpreted, return NULL_TREE. */
8615 static tree
8617 {
8620 double_int result;
8621 FIXED_VALUE_TYPE fixed_value;
8631 }
8634 /* Subroutine of native_interpret_expr. Interpret the contents of
8635 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8636 If the buffer cannot be interpreted, return NULL_TREE. */
8638 tree
8640 {
8644 /* There are always 32 bits in each long, no matter the size of
8645 the hosts long. We handle floating point representations with
8646 up to 192 bits. */
8647 REAL_VALUE_TYPE r;
8657 {
8658 /* Both OFFSET and BYTE index within a long;
8659 bitpos indexes the whole float. */
8662 {
8669 else
8671 }
8672 else
8673 {
8676 {
8677 /* Reverse bytes within each long, or within the entire float
8678 if it's smaller than a long (for HFmode). */
8681 }
8682 }
8686 }
8690 }
8693 /* Subroutine of native_interpret_expr. Interpret the contents of
8694 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8695 If the buffer cannot be interpreted, return NULL_TREE. */
8697 static tree
8699 {
8714 }
8716 /* Read a vector of type TYPE from the target memory image given by BYTES,
8717 which contains LEN bytes. The vector is known to be encodable using
8718 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8720 Return the vector on success, otherwise return null. */
8722 static tree
8726 {
8730 {
8731 /* This is the only case in which elements can be smaller than a byte.
8732 Element 0 is always in the lsb of the containing byte. */
8739 {
8746 }
8748 }
8756 {
8762 }
8764 }
8766 /* Subroutine of native_interpret_expr. Interpret the contents of
8767 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8768 If the buffer cannot be interpreted, return NULL_TREE. */
8770 static tree
8772 {
8773 tree etype;
8784 }
8787 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8788 the buffer PTR of length LEN as a constant of type TYPE. For
8789 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8790 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8791 return NULL_TREE. */
8793 tree
8795 {
8797 {
8808 {
8809 /* For floating point values in composite modes, punt if this
8810 folding doesn't preserve bit representation. As the mode doesn't
8811 have fixed precision while GCC pretends it does, there could be
8812 valid values that GCC can't really represent accurately.
8813 See PR95450. Even for other modes, e.g. x86 XFmode can have some
8814 bit combinationations which GCC doesn't preserve. */
8824 }
8838 }
8839 }
8841 /* Returns true if we can interpret the contents of a native encoding
8842 as TYPE. */
8844 bool
8846 {
8848 {
8862 }
8863 }
8865 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8866 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8868 tree
8871 {
8874 {
8881 {
8885 }
8890 {
8895 {
8900 }
8904 eltsz);
8908 }
8910 }
8914 {
8922 {
8925 {
8926 poly_int64 bitoffset;
8931 else
8941 }
8942 else
8943 {
8961 HOST_WIDE_INT rpos;
8964 else
8965 {
8968 }
8977 }
8978 }
8981 {
8991 }
8995 {
9000 }
9007 {
9011 /* FIXME: Figure out how to handle PDP endian bitfields. */
9017 else
9021 }
9023 }
9025 }
9027 /* Routines for manipulation of native_encode_expr encoded data if the encoded
9028 or extracted constant positions and/or sizes aren't byte aligned. */
9030 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
9031 bits between adjacent elements. AMNT should be within
9032 [0, BITS_PER_UNIT).
9033 Example, AMNT = 2:
9034 00011111|11100000 << 2 = 01111111|10000000
9035 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
9037 void
9040 {
9049 {
9055 {
9058 }
9059 }
9060 }
9062 /* Like shift_bytes_in_array_left but for big-endian.
9063 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9064 bits between adjacent elements. AMNT should be within
9065 [0, BITS_PER_UNIT).
9066 Example, AMNT = 2:
9067 00011111|11100000 >> 2 = 00000111|11111000
9068 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9070 void
9073 {
9081 {
9088 }
9089 }
9091 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9092 directly on the VECTOR_CST encoding, in a way that works for variable-
9093 length vectors. Return the resulting VECTOR_CST on success or null
9094 on failure. */
9096 static tree
9098 {
9110 /* We can only preserve the semantics of a stepped pattern if the new
9111 vector element is an integer of the same size. */
9116 /* The number of bits needed to encode one element from every pattern
9117 of the original vector. */
9118 unsigned int expr_sequence_bits
9121 /* The number of bits needed to encode one element from every pattern
9122 of the result. */
9123 unsigned int type_sequence_bits
9126 /* Don't try to read more bytes than are available, which can happen
9127 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9128 The general VIEW_CONVERT handling can cope with that case, so there's
9129 no point complicating things here. */
9132 BITS_PER_UNIT);
9137 /* Get enough bytes of EXPR to form the new encoding. */
9145 /* Reencode the bytes as TYPE. */
9149 }
9151 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9152 TYPE at compile-time. If we're unable to perform the conversion
9153 return NULL_TREE. */
9155 static tree
9157 {
9158 /* We support up to 512-bit values (for V8DFmode). */
9162 /* Check that the host and target are sane. */
9175 }
9177 /* Build an expression for the address of T. Folds away INDIRECT_REF
9178 to avoid confusing the gimplify process. */
9180 tree
9182 {
9183 /* The size of the object is not relevant when talking about its address. */
9188 {
9193 }
9196 {
9201 }
9208 {
9213 }
9214 else
9218 }
9220 /* Build an expression for the address of T. */
9222 tree
9224 {
9228 }
9230 /* Fold a unary expression of code CODE and type TYPE with operand
9231 OP0. Return the folded expression if folding is successful.
9232 Otherwise, return NULL_TREE. */
9234 tree
9236 {
9237 tree tem;
9238 tree arg0;
9246 {
9249 {
9250 /* Don't use STRIP_NOPS, because signedness of argument type
9251 matters. */
9253 }
9254 else
9255 {
9256 /* Strip any conversions that don't change the mode. This
9257 is safe for every expression, except for a comparison
9258 expression because its signedness is derived from its
9259 operands.
9261 Note that this is done as an internal manipulation within
9262 the constant folder, in order to find the simplest
9263 representation of the arguments so that their form can be
9264 studied. In any cases, the appropriate type conversions
9265 should be put back in the tree that will get out of the
9266 constant folder. */
9268 }
9271 {
9274 {
9278 }
9279 }
9280 }
9287 {
9294 {
9308 /* If this was a conversion, and all we did was to move into
9309 inside the COND_EXPR, bring it back out. But leave it if
9310 it is a conversion from integer to integer and the
9311 result precision is no wider than a word since such a
9312 conversion is cheap and may be optimized away by combine,
9313 while it couldn't if it were outside the COND_EXPR. Then return
9314 so we don't get into an infinite recursion loop taking the
9315 conversion out and then back in. */
9327 && (INTEGRAL_TYPE_P
9340 }
9341 }
9344 {
9350 CASE_CONVERT:
9354 {
9355 /* If we have (type) (a CMP b) and type is an integral type, return
9356 new expression involving the new type. Canonicalize
9357 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9358 non-integral type.
9359 Do not fold the result as that would not simplify further, also
9360 folding again results in recursions. */
9370 }
9372 /* Handle (T *)&A.B.C for A being of type T and B and C
9373 living at offset zero. This occurs frequently in
9374 C++ upcasting and then accessing the base. */
9378 {
9380 tree offset;
9381 machine_mode mode;
9383 tree base
9387 /* If the reference was to a (constant) zero offset, we can use
9388 the address of the base if it has the same base type
9389 as the result type and the pointer type is unqualified. */
9397 }
9401 /* Detect assigning a bitfield. */
9403 && DECL_BIT_FIELD
9405 {
9406 /* Don't leave an assignment inside a conversion
9407 unless assigning a bitfield. */
9409 /* First do the assignment, then return converted constant. */
9414 }
9416 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9417 constants (if x has signed type, the sign bit cannot be set
9418 in c). This folds extension into the BIT_AND_EXPR.
9419 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9420 very likely don't have maximal range for their precision and this
9421 transformation effectively doesn't preserve non-maximal ranges. */
9425 {
9436 <= HOST_BITS_PER_WIDE_INT
9438 {
9442 cst &= HOST_WIDE_INT_M1U
9446 && !flag_syntax_only
9449 {
9453 }
9454 }
9456 {
9461 }
9462 }
9464 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9465 cast (T1)X will fold away. We assume that this happens when X itself
9466 is a cast. */
9470 {
9474 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9475 when the pointed type needs higher alignment than
9476 the p+ first operand's pointed type. */
9483 /* Similarly, avoid this optimization in GENERIC for -fsanitize=null
9484 when type is a reference type and arg00's type is not,
9485 because arg00 could be validly nullptr and if arg01 doesn't return,
9486 we don't want false positive binding of reference to nullptr. */
9488 && !in_gimple_form
9495 }
9497 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9498 of the same precision, and X is an integer type not narrower than
9499 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9505 {
9511 }
9513 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9514 type of X and Y (integer types only). */
9521 {
9522 /* Be careful not to introduce new overflows. */
9523 tree mult_type;
9526 else
9530 {
9537 }
9538 }
9544 {
9551 }
9562 /* Convert fabs((double)float) into (double)fabsf(float). */
9565 {
9571 targ0));
9572 }
9576 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9595 /* Note that the operand of this must be an int
9596 and its values must be 0 or 1.
9597 ("true" is a fixed value perhaps depending on the language,
9598 but we don't handle values other than 1 correctly yet.) */
9605 /* Fold *&X to X if X is an lvalue. */
9607 {
9614 }
9620 }
9623 /* If the operation was a conversion do _not_ mark a resulting constant
9624 with TREE_OVERFLOW if the original constant was not. These conversions
9625 have implementation defined behavior and retaining the TREE_OVERFLOW
9626 flag here would confuse later passes such as VRP. */
9627 tree
9630 {
9639 }
9641 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9642 operands OP0 and OP1. LOC is the location of the resulting expression.
9643 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9644 Return the folded expression if folding is successful. Otherwise,
9645 return NULL_TREE. */
9646 static tree
9649 {
9650 tree tem;
9652 /* We only do these simplifications if we are optimizing. */
9656 /* Check for things like (A || B) && (A || C). We can convert this
9657 to A || (B && C). Note that either operator can be any of the four
9658 truth and/or operations and the transformation will still be
9659 valid. Also note that we only care about order for the
9660 ANDIF and ORIF operators. If B contains side effects, this
9661 might change the truth-value of A. */
9668 {
9688 /* This case if tricky because we must either have commutative
9689 operators or else A10 must not have side-effects. */
9695 a01);
9696 }
9698 /* See if we can build a range comparison. */
9704 {
9708 }
9712 {
9716 }
9718 /* Check for the possibility of merging component references. If our
9719 lhs is another similar operation, try to merge its rhs with our
9720 rhs. Then try to merge our lhs and rhs. */
9731 logical_op_non_short_circuit
9739 {
9746 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9747 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9748 We don't want to pack more than two leafs to a non-IF AND/OR
9749 expression.
9750 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9751 equal to IF-CODE, then we don't want to add right-hand operand.
9752 If the inner right-hand side of left-hand operand has
9753 side-effects, or isn't simple, then we can't add to it,
9754 as otherwise we might destroy if-sequence. */
9757 /* Needed for sequence points to handle trappings, and
9758 side-effects. */
9760 {
9762 arg1);
9764 tem);
9765 }
9766 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9767 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9770 /* Needed for sequence points to handle trappings, and
9771 side-effects. */
9773 {
9778 }
9779 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9780 into (A OR B).
9781 For sequence point consistancy, we need to check for trapping,
9782 and side-effects. */
9786 }
9789 }
9791 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9792 by changing CODE to reduce the magnitude of constants involved in
9793 ARG0 of the comparison.
9794 Returns a canonicalized comparison tree if a simplification was
9795 possible, otherwise returns NULL_TREE.
9796 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9797 valid if signed overflow is undefined. */
9799 static tree
9803 {
9808 /* Match A +- CST code arg1. We can change this only if overflow
9809 is undefined. */
9812 /* In principle pointers also have undefined overflow behavior,
9813 but that causes problems elsewhere. */
9820 /* Identify the constant in arg0 and its sign. */
9824 /* Overflowed constants and zero will cause problems. */
9829 /* See if we can reduce the magnitude of the constant in
9830 arg0 by changing the comparison code. */
9831 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9835 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9839 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9843 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9847 else
9851 /* Now build the constant reduced in magnitude. But not if that
9852 would produce one outside of its types range. */
9868 }
9870 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9871 overflow further. Try to decrease the magnitude of constants involved
9872 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9873 and put sole constants at the second argument position.
9874 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9876 static tree
9879 {
9880 tree t;
9885 /* Try canonicalization by simplifying arg0. */
9890 {
9894 }
9896 /* Try canonicalization by simplifying arg1 using the swapped
9897 comparison. */
9905 }
9907 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9908 space. This is used to avoid issuing overflow warnings for
9909 expressions like &p->x which cannot wrap. */
9911 static bool
9913 {
9920 poly_wide_int wi_offset;
9926 else
9931 precision);
9946 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9947 array. */
9956 }
9958 /* Return a positive integer when the symbol DECL is known to have
9959 a nonzero address, zero when it's known not to (e.g., it's a weak
9960 symbol), and a negative integer when the symbol is not yet in the
9961 symbol table and so whether or not its address is zero is unknown.
9962 For function local objects always return positive integer. */
9963 static int
9965 {
9966 /* Normally, don't do anything for variables and functions before symtab is
9967 built; it is quite possible that DECL will be declared weak later.
9968 But if folding_initializer, we need a constant answer now, so create
9969 the symtab entry and prevent later weak declaration. */
9972 = (folding_initializer
9977 /* Function local objects are never NULL. */
9985 }
9987 /* Subroutine of fold_binary. This routine performs all of the
9988 transformations that are common to the equality/inequality
9989 operators (EQ_EXPR and NE_EXPR) and the ordering operators
9990 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
9991 fold_binary should call fold_binary. Fold a comparison with
9992 tree code CODE and type TYPE with operands OP0 and OP1. Return
9993 the folded comparison or NULL_TREE. */
9995 static tree
9998 {
10008 /* For comparisons of pointers we can decompose it to a compile time
10009 comparison of the base objects and the offsets into the object.
10010 This requires at least one operand being an ADDR_EXPR or a
10011 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
10017 {
10020 machine_mode mode;
10024 /* Get base and offset for the access. Strip ADDR_EXPR for
10025 get_inner_reference, but put it back by stripping INDIRECT_REF
10026 off the base object if possible. indirect_baseN will be true
10027 if baseN is not an address but refers to the object itself. */
10030 {
10031 base0
10037 else
10039 }
10041 {
10045 {
10046 base0
10052 else
10054 }
10057 else
10061 {
10068 }
10069 }
10073 {
10074 base1
10080 else
10082 }
10084 {
10088 {
10089 base1
10095 else
10097 }
10100 else
10104 {
10111 }
10112 }
10114 /* If we have equivalent bases we might be able to simplify. */
10118 {
10119 /* We can fold this expression to a constant if the non-constant
10120 offset parts are equal. */
10124 && (equality_code
10125 || (indirect_base0
10128 {
10134 "occur when comparing P +- C1 with "
10136 WARN_STRICT_OVERFLOW_CONDITIONAL);
10139 {
10177 }
10178 }
10179 /* We can simplify the comparison to a comparison of the variable
10180 offset parts if the constant offset parts are equal.
10181 Be careful to use signed sizetype here because otherwise we
10182 mess with array offsets in the wrong way. This is possible
10183 because pointer arithmetic is restricted to retain within an
10184 object and overflow on pointer differences is undefined as of
10185 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10187 && (equality_code
10188 || (indirect_base0
10191 {
10192 /* By converting to signed sizetype we cover middle-end pointer
10193 arithmetic which operates on unsigned pointer types of size
10194 type size and ARRAY_REF offsets which are properly sign or
10195 zero extended from their type in case it is narrower than
10196 sizetype. */
10199 else
10203 else
10210 "occur when comparing P +- C1 with "
10212 WARN_STRICT_OVERFLOW_COMPARISON);
10215 }
10216 }
10217 /* For equal offsets we can simplify to a comparison of the
10218 base addresses. */
10220 && (indirect_base0
10222 && (indirect_base1
10227 {
10233 }
10234 /* Comparison between an ordinary (non-weak) symbol and a null
10235 pointer can be eliminated since such symbols must have a non
10236 null address. In C, relational expressions between pointers
10237 to objects and null pointers are undefined. The results
10238 below follow the C++ rules with the additional property that
10239 every object pointer compares greater than a null pointer.
10240 */
10243 /* Avoid folding references to struct members at offset 0 to
10244 prevent tests like '&ptr->firstmember == 0' from getting
10245 eliminated. When ptr is null, although the -> expression
10246 is strictly speaking invalid, GCC retains it as a matter
10247 of QoI. See PR c/44555. */
10250 && indirect_base0
10251 /* The caller guarantees that when one of the arguments is
10252 constant (i.e., null in this case) it is second. */
10254 {
10256 {
10267 }
10268 }
10269 }
10271 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10272 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10273 the resulting offset is smaller in absolute value than the
10274 original one and has the same sign. */
10283 {
10288 tree cst;
10290 "occur when combining constants around "
10293 /* Put the constant on the side where it doesn't overflow and is
10294 of lower absolute value and of same sign than before. */
10301 {
10304 variable1,
10308 }
10316 {
10322 variable2);
10323 }
10324 }
10330 /* If we are comparing an expression that just has comparisons
10331 of two integer values, arithmetic expressions of those comparisons,
10332 and constants, we can simplify it. There are only three cases
10333 to check: the two values can either be equal, the first can be
10334 greater, or the second can be greater. Fold the expression for
10335 those three values. Since each value must be 0 or 1, we have
10336 eight possibilities, each of which corresponds to the constant 0
10337 or 1 or one of the six possible comparisons.
10339 This handles common cases like (a > b) == 0 but also handles
10340 expressions like ((x > y) - (y > x)) > 0, which supposedly
10341 occur in macroized code. */
10344 {
10348 /* Don't handle degenerate cases here; they should already
10349 have been handled anyway. */
10358 {
10362 /* We can't just pass T to eval_subst in case cval1 or cval2
10363 was the same as ARG1. */
10365 tree high_result
10369 arg1);
10370 tree equal_result
10374 arg1);
10375 tree low_result
10379 arg1);
10381 /* All three of these results should be 0 or 1. Confirm they are.
10382 Then use those values to select the proper code to use. */
10387 {
10388 /* Make a 3-bit mask with the high-order bit being the
10389 value for `>', the next for '=', and the low for '<'. */
10393 {
10395 /* Always false. */
10416 /* Always true. */
10418 }
10421 }
10422 }
10423 }
10426 }
10429 /* Subroutine of fold_binary. Optimize complex multiplications of the
10430 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10431 argument EXPR represents the expression "z" of type TYPE. */
10433 static tree
10435 {
10440 {
10443 }
10445 {
10448 }
10449 else
10450 {
10454 }
10463 }
10466 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10467 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10468 true if successful. */
10470 static bool
10472 {
10477 {
10480 }
10482 {
10488 else
10490 }
10491 else
10497 }
10499 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10500 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10501 NULL_TREE otherwise. */
10503 tree
10505 {
10526 {
10527 HOST_WIDE_INT index;
10533 }
10536 {
10542 }
10543 else
10545 }
10547 /* Try to fold a pointer difference of type TYPE two address expressions of
10548 array references AREF0 and AREF1 using location LOC. Return a
10549 simplified expression for the difference or NULL_TREE. */
10551 static tree
10555 {
10560 /* If the bases are array references as well, recurse. If the bases
10561 are pointer indirections compute the difference of the pointers.
10562 If the bases are equal, we are set. */
10565 && (base_offset
10567 use_pointer_diff)))
10570 && (base_offset
10571 = use_pointer_diff
10581 {
10587 base_offset,
10590 }
10592 }
10594 /* If the real or vector real constant CST of type TYPE has an exact
10595 inverse, return it, else return NULL. */
10597 tree
10599 {
10600 REAL_VALUE_TYPE r;
10601 tree unit_type;
10602 machine_mode mode;
10605 {
10615 {
10619 tree_vector_builder elts;
10624 {
10629 }
10632 }
10636 }
10637 }
10639 /* Mask out the tz least significant bits of X of type TYPE where
10640 tz is the number of trailing zeroes in Y. */
10641 static wide_int
10643 {
10648 }
10650 /* Return true when T is an address and is known to be nonzero.
10651 For floating point we further ensure that T is not denormal.
10652 Similar logic is present in nonzero_address in rtlanal.h.
10654 If the return value is based on the assumption that signed overflow
10655 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10656 change *STRICT_OVERFLOW_P. */
10658 static bool
10660 {
10664 /* Doing something useful for floating point would need more work. */
10670 {
10673 strict_overflow_p);
10679 strict_overflow_p);
10687 }
10690 {
10693 strict_overflow_p);
10701 strict_overflow_p);
10715 strict_overflow_p);
10719 strict_overflow_p);
10722 {
10734 }
10738 }
10740 }
10742 /* Return true when T is an address and is known to be nonzero.
10743 Handle warnings about undefined signed overflow. */
10745 bool
10747 {
10754 "determining that expression is always "
10756 WARN_STRICT_OVERFLOW_MISC);
10758 }
10760 /* Return true if T is known not to be equal to an integer W. */
10762 bool
10764 {
10765 int_range_max vr;
10767 {
10777 else
10782 /* If T has some known zero bits and W has any of those bits set,
10783 then T is known not to be equal to W. */
10791 }
10792 }
10794 /* Fold a binary expression of code CODE and type TYPE with operands
10795 OP0 and OP1. LOC is the location of the resulting expression.
10796 Return the folded expression if folding is successful. Otherwise,
10797 return NULL_TREE. */
10799 tree
10802 {
10817 /* Strip any conversions that don't change the mode. This is
10818 safe for every expression, except for a comparison expression
10819 because its signedness is derived from its operands. So, in
10820 the latter case, only strip conversions that don't change the
10821 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10822 preserved.
10824 Note that this is done as an internal manipulation within the
10825 constant folder, in order to find the simplest representation
10826 of the arguments so that their form can be studied. In any
10827 cases, the appropriate type conversions should be put back in
10828 the tree that will get out of the constant folder. */
10831 {
10834 }
10835 else
10836 {
10839 }
10841 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10842 constant but we can't do arithmetic on them. */
10844 {
10847 {
10851 }
10852 }
10854 /* If this is a commutative operation, and ARG0 is a constant, move it
10855 to ARG1 to reduce the number of tests below. */
10860 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10861 to ARG1 to reduce the number of tests below. */
10870 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10872 First check for cases where an arithmetic operation is applied to a
10873 compound, conditional, or comparison operation. Push the arithmetic
10874 operation inside the compound or conditional to see if any folding
10875 can then be done. Convert comparison to conditional for this purpose.
10876 The also optimizes non-constant cases that used to be done in
10877 expand_expr.
10879 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10880 one of the operands is a comparison and the other is a comparison, a
10881 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10882 code below would make the expression more complex. Change it to a
10883 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10884 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10897 {
10901 boolean_type_node,
10909 }
10913 {
10915 {
10920 tem);
10921 }
10923 {
10928 tem);
10929 }
10934 {
10940 }
10945 {
10951 }
10952 }
10955 {
10957 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10960 {
10966 }
10968 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10971 {
10972 tree base;
10973 poly_int64 coffset;
10982 }
10987 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
10993 arg1),
10995 arg0)));
11001 {
11002 /* X + (X / CST) * -CST is X % CST. */
11007 {
11016 cst0));
11017 }
11018 }
11020 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
11021 one. Make sure the type is not saturating and has the signedness of
11022 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11023 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11030 {
11034 }
11037 {
11038 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
11039 (plus (plus (mult) (mult)) (foo)) so that we can
11040 take advantage of the factoring cases below. */
11049 {
11055 else
11068 parg0),
11070 marg)),
11074 return
11080 parg1)));
11081 }
11082 }
11083 else
11084 {
11085 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11086 to __complex__ ( x, y ). This is not the same for SNaNs or
11087 if signed zeros are involved. */
11091 {
11098 {
11102 {
11108 }
11110 {
11116 }
11117 }
11118 }
11120 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11121 We associate floats only if the user has specified
11122 -fassociative-math. */
11126 {
11131 {
11132 tree tree0;
11135 }
11136 }
11137 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11138 We associate floats only if the user has specified
11139 -fassociative-math. */
11143 {
11148 {
11149 tree tree0;
11152 }
11153 }
11154 }
11156 bit_rotate:
11157 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11158 is a rotate of A by C1 bits. */
11159 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11160 is a rotate of A by B bits.
11161 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11162 though in this case CODE must be | and not + or ^, otherwise
11163 it doesn't return A when B is 0. */
11164 {
11166 tree rtype;
11175 /* Only create rotates in complete modes. Other cases are not
11176 expanded properly. */
11179 {
11192 {
11197 }
11202 {
11205 code0 == LSHIFT_EXPR
11208 }
11210 {
11220 {
11224 orig_tree01);
11226 }
11227 }
11231 {
11242 {
11246 orig_tree01);
11248 }
11249 }
11250 }
11251 }
11253 associate:
11254 /* In most languages, can't associate operations on floats through
11255 parentheses. Rather than remember where the parentheses were, we
11256 don't associate floats at all, unless the user has specified
11257 -fassociative-math.
11258 And, we need to make sure type is not saturating. */
11263 {
11269 /* Split both trees into variables, constants, and literals. Then
11270 associate each group together, the constants with literals,
11271 then the result with variables. This increases the chances of
11272 literals being recombined later and of generating relocatable
11273 expressions for the sum of a constant and literal. */
11281 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11285 /* With undefined overflow prefer doing association in a type
11286 which wraps on overflow, if that is one of the operand types. */
11289 {
11297 }
11299 /* With undefined overflow we can only associate constants with one
11300 variable, and constants whose association doesn't overflow. */
11303 {
11305 {
11306 /* ??? If split_tree would handle NEGATE_EXPR we could
11307 simply reject these cases and the allowed cases would
11308 be the var0/minus_var1 ones. */
11314 {
11317 }
11324 {
11327 }
11333 /* The only case we can still associate with two variables
11334 is if they cancel out. */
11338 }
11344 }
11346 /* Only do something if we found more than two objects. Otherwise,
11347 nothing has changed and we risk infinite recursion. */
11355 {
11367 {
11371 }
11373 {
11377 }
11379 /* Preserve the MINUS_EXPR if the negative part of the literal is
11380 greater than the positive part. Otherwise, the multiplicative
11381 folding code (i.e extract_muldiv) may be fooled in case
11382 unsigned constants are subtracted, like in the following
11383 example: ((X*2 + 4) - 8U)/2. */
11385 {
11389 /* But avoid ending up with only negated parts. */
11391 {
11395 }
11396 else
11397 {
11401 }
11402 }
11404 /* Don't introduce overflows through reassociation. */
11409 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11416 /* Eliminate minus_con0. */
11418 {
11425 else
11428 }
11430 /* Eliminate minus_var0. */
11432 {
11436 else
11439 }
11441 return
11444 }
11445 }
11451 /* Fold &a[i] - &a[j] to i-j. */
11456 {
11460 code
11464 }
11466 /* Further transformations are not for pointers. */
11470 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11473 /* If arg0 is e.g. unsigned int and type is int, then this could
11474 introduce UB, because if A is INT_MIN at runtime, the original
11475 expression can be well defined while the latter is not.
11476 See PR83269. */
11485 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11486 __complex__ ( x, -y ). This is not the same for SNaNs or if
11487 signed zeros are involved. */
11491 {
11498 {
11502 {
11504 arg1r ? arg1r
11509 }
11511 {
11515 arg1i ? arg1i
11518 }
11519 }
11520 }
11522 /* A - B -> A + (-B) if B is easily negatable. */
11526 /* Avoid this transformation if B is a positive REAL_CST. */
11534 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11535 one. Make sure the type is not saturating and has the signedness of
11536 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11537 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11544 {
11548 }
11554 {
11555 /* Transform x * -C into -x * C if x is easily negatable. */
11570 {
11573 "occur when simplifying "
11575 WARN_STRICT_OVERFLOW_MISC);
11577 }
11579 /* Optimize z * conj(z) for integer complex numbers. */
11586 }
11587 else
11588 {
11589 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11590 This is not the same for NaNs or if signed zeros are
11591 involved. */
11597 {
11600 return
11606 return
11611 }
11613 /* Optimize z * conj(z) for floating point complex numbers.
11614 Guarded by flag_unsafe_math_optimizations as non-finite
11615 imaginary components don't produce scalar results. */
11624 }
11628 /* Canonicalize (X & C1) | C2. */
11632 {
11637 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11645 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11647 {
11650 }
11652 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11653 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11654 mode which allows further optimizations. */
11659 {
11664 {
11667 }
11668 }
11671 {
11676 }
11677 }
11679 /* See if this can be simplified into a rotate first. If that
11680 is unsuccessful continue in the association code. */
11684 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11692 /* See if this can be simplified into a rotate first. If that
11693 is unsuccessful continue in the association code. */
11697 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11702 {
11703 tree tem2;
11710 }
11711 /* Fold ~X & 1 as (X & 1) == 0. */
11715 {
11716 tree tem2;
11723 }
11724 /* Fold !X & 1 as X == 0. */
11727 {
11731 }
11733 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11734 multiple of 1 << CST. */
11736 {
11743 }
11745 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11746 bits from CST2. */
11750 {
11752 wide_int masked
11759 {
11760 /* Avoid the transform if arg1 is a mask of some
11761 mode which allows further optimizations. */
11768 }
11769 }
11771 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11774 {
11779 return
11781 }
11786 /* Don't touch a floating-point divide by zero unless the mode
11787 of the constant can represent infinity. */
11793 /* (-A) / (-B) -> A / B */
11805 /* Fall through */
11808 /* Simplify A / (B << N) where A and B are positive and B is
11809 a power of 2, to A >> (N + log2(B)). */
11814 {
11817 {
11825 WARN_STRICT_OVERFLOW_MISC);
11831 }
11832 }
11834 /* Fall through */
11842 /* Convert -A / -B to A / B when the type is signed and overflow is
11843 undefined. */
11847 {
11850 "when distributing negation across "
11852 WARN_STRICT_OVERFLOW_MISC);
11857 }
11861 {
11864 "when distributing negation across "
11866 WARN_STRICT_OVERFLOW_MISC);
11871 }
11873 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11874 operation, EXACT_DIV_EXPR.
11876 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11877 At one time others generated faster code, it's not clear if they do
11878 after the last round to changes to the DIV code in expmed.cc. */
11889 {
11893 WARN_STRICT_OVERFLOW_MISC);
11895 }
11907 {
11911 WARN_STRICT_OVERFLOW_MISC);
11913 }
11921 /* Since negative shift count is not well-defined,
11922 don't try to compute it in the compiler. */
11928 /* If we have a rotate of a bit operation with the rotate count and
11929 the second operand of the bit operation both constant,
11930 permute the two operations. */
11936 {
11944 }
11946 /* Two consecutive rotates adding up to the some integer
11947 multiple of the precision of the type can be ignored. */
11963 /* Note that the operands of this must be ints
11964 and their values must be 0 or 1.
11965 ("true" is a fixed value perhaps depending on the language.) */
11966 /* If first arg is constant zero, return it. */
11969 /* FALLTHRU */
11971 /* If either arg is constant true, drop it. */
11975 /* Preserve sequence points. */
11978 /* If second arg is constant zero, result is zero, but first arg
11979 must be evaluated. */
11982 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11983 case will be handled here. */
11987 /* !X && X is always false. */
11991 /* X && !X is always false. */
11996 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11997 means A >= Y && A != MAX, but in this case we know that
11998 A < X <= MAX. */
12002 {
12014 }
12023 /* Note that the operands of this must be ints
12024 and their values must be 0 or true.
12025 ("true" is a fixed value perhaps depending on the language.) */
12026 /* If first arg is constant true, return it. */
12029 /* FALLTHRU */
12031 /* If either arg is constant zero, drop it. */
12035 /* Preserve sequence points. */
12038 /* If second arg is constant true, result is true, but we must
12039 evaluate first arg. */
12042 /* Likewise for first arg, but note this only occurs here for
12043 TRUTH_OR_EXPR. */
12047 /* !X || X is always true. */
12051 /* X || !X is always true. */
12056 /* (X && !Y) || (!X && Y) is X ^ Y */
12059 {
12076 }
12085 /* If the second arg is constant zero, drop it. */
12088 /* If the second arg is constant true, this is a logical inversion. */
12090 {
12093 }
12094 /* Identical arguments cancel to zero. */
12098 /* !X ^ X is always true. */
12103 /* X ^ !X is always true. */
12119 /* bool_var != 1 becomes !bool_var. */
12126 /* bool_var == 0 becomes !bool_var. */
12133 /* !exp != 0 becomes !exp */
12138 /* If this is an EQ or NE comparison with zero and ARG0 is
12139 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12140 two operations, but the latter can be done in one less insn
12141 on machines that have only two-operand insns or on which a
12142 constant cannot be the first operand. */
12145 {
12150 {
12158 }
12161 {
12169 }
12170 }
12172 /* If this is a comparison of a field, we may be able to simplify it. */
12175 /* Handle the constant case even without -O
12176 to make sure the warnings are given. */
12178 {
12182 }
12184 /* Optimize comparisons of strlen vs zero to a compare of the
12185 first character of the string vs zero. To wit,
12186 strlen(ptr) == 0 => *ptr == 0
12187 strlen(ptr) != 0 => *ptr != 0
12188 Other cases should reduce to one of these two (or a constant)
12189 due to the return value of strlen being unsigned. */
12191 {
12199 {
12200 tree ptrtype
12202 TYPE_QUAL_CONST));
12208 }
12209 }
12211 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12212 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12216 {
12221 {
12223 {
12226 }
12229 }
12230 }
12232 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12233 (X & C) == 0 when C is a single bit. */
12238 {
12245 arg1));
12246 }
12248 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12249 constant C is a power of two, i.e. a single bit. */
12256 {
12260 }
12262 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12263 when is C is a power of two, i.e. a single bit. */
12270 {
12276 }
12280 {
12283 }
12287 {
12294 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12295 operand_equal_p guarantees no side-effects so we don't need
12296 to use omit_one_operand on Z. */
12300 arg10));
12304 arg11));
12308 arg10));
12312 arg11));
12314 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12317 {
12323 }
12324 }
12326 /* Attempt to simplify equality/inequality comparisons of complex
12327 values. Only lower the comparison if the result is known or
12328 can be simplified to a single scalar comparison. */
12333 {
12338 {
12341 }
12342 else
12343 {
12346 }
12349 {
12352 }
12353 else
12354 {
12357 }
12361 {
12363 {
12368 }
12369 else
12370 {
12375 }
12376 }
12380 {
12382 {
12387 }
12388 else
12389 {
12394 }
12395 }
12396 }
12408 /* Transform comparisons of the form X +- C CMP X. */
12413 {
12418 /* (X - c) > X becomes false. */
12424 /* Likewise (X + c) < X becomes false. */
12430 /* Convert (X - c) <= X to true. */
12437 /* Convert (X + c) >= X to true. */
12443 }
12445 /* If we are comparing an ABS_EXPR with a constant, we can
12446 convert all the cases into explicit comparisons, but they may
12447 well not be faster than doing the ABS and one comparison.
12448 But ABS (X) <= C is a range comparison, which becomes a subtraction
12449 and a comparison, and is probably faster. */
12463 /* Convert ABS_EXPR<x> >= 0 to true. */
12470 {
12473 "when simplifying comparison of "
12475 WARN_STRICT_OVERFLOW_CONDITIONAL);
12478 arg0);
12479 }
12481 /* Convert ABS_EXPR<x> < 0 to false. */
12486 {
12489 "when simplifying comparison of "
12491 WARN_STRICT_OVERFLOW_CONDITIONAL);
12494 arg0);
12495 }
12497 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12498 and similarly for >= into !=. */
12508 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12509 otherwise Y might be >= # of bits in X's type and thus e.g.
12510 (unsigned char) (1 << Y) for Y 15 might be 0.
12511 If the cast is widening, then 1 << Y should have unsigned type,
12512 otherwise if Y is number of bits in the signed shift type minus 1,
12513 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12514 31 might be 0xffffffff80000000. */
12527 {
12533 }
12545 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12546 {
12558 }
12563 /* When pedantic, a compound expression can be neither an lvalue
12564 nor an integer constant expression. */
12567 /* Don't let (0, 0) be null pointer constant. */
12575 }
12577 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12578 ((A & N) + B) & M -> (A + B) & M
12579 Similarly if (N & M) == 0,
12580 ((A | N) + B) & M -> (A + B) & M
12581 and for - instead of + (or unary - instead of +)
12582 and/or ^ instead of |.
12583 If B is constant and (B & M) == 0, fold into A & M.
12585 This function is a helper for match.pd patterns. Return non-NULL
12586 type in which the simplified operation should be performed only
12587 if any optimization is possible.
12589 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12590 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12591 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12592 +/-. */
12593 tree
12598 {
12613 wide_int cst0;
12615 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12616 arg1 (M) is == (1LL << cst) - 1.
12617 Store C into PMOP[0] and D into PMOP[1]. */
12624 {
12631 {
12634 }
12637 /* If C or D is of the form (A & N) where
12638 (N & M) == M, or of the form (A | N) or
12639 (A ^ N) where (N & M) == 0, replace it with A. */
12645 /* If C or D is a N where (N & M) == 0, it can be
12646 omitted (replaced with 0). */
12651 /* Similarly, with C - N where (-N & M) == 0. */
12659 }
12661 /* Only build anything new if we optimized one or both arguments above. */
12667 else
12669 }
12671 /* Used by contains_label_[p1]. */
12673 struct contains_label_data
12674 {
12677 };
12679 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12680 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12681 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12683 static tree
12685 {
12688 {
12699 {
12707 }
12716 }
12717 }
12719 /* Return whether the sub-tree ST contains a label which is accessible from
12720 outside the sub-tree. */
12722 static bool
12724 {
12728 }
12730 /* Fold a ternary expression of code CODE and type TYPE with operands
12731 OP0, OP1, and OP2. Return the folded expression if folding is
12732 successful. Otherwise, return NULL_TREE. */
12734 tree
12737 {
12738 tree tem;
12745 /* If this is a commutative operation, and OP0 is a constant, move it
12746 to OP1 to reduce the number of tests below. */
12755 /* Strip any conversions that don't change the mode. This is safe
12756 for every expression, except for a comparison expression because
12757 its signedness is derived from its operands. So, in the latter
12758 case, only strip conversions that don't change the signedness.
12760 Note that this is done as an internal manipulation within the
12761 constant folder, in order to find the simplest representation of
12762 the arguments so that their form can be studied. In any cases,
12763 the appropriate type conversions should be put back in the tree
12764 that will get out of the constant folder. */
12766 {
12769 }
12772 {
12775 }
12778 {
12781 }
12784 {
12788 {
12794 }
12799 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12800 so all simple results must be passed through pedantic_non_lvalue. */
12802 {
12805 /* Only optimize constant conditions when the selected branch
12806 has the same type as the COND_EXPR. This avoids optimizing
12807 away "c ? x : throw", where the throw has a void type.
12808 Avoid throwing away that operand which contains label. */
12815 }
12817 {
12824 {
12827 {
12835 }
12840 }
12841 }
12843 /* If we have A op B ? A : C, we may be able to convert this to a
12844 simpler expression, depending on the operation and the values
12845 of B and C. Signed zeros prevent all of these transformations,
12846 for reasons given above each one.
12848 Also try swapping the arguments and inverting the conditional. */
12852 {
12859 }
12864 {
12871 arg00,
12872 arg01,
12876 }
12878 /* If the second operand is simpler than the third, swap them
12879 since that produces better jump optimization results. */
12882 {
12884 /* See if this can be inverted. If it can't, possibly because
12885 it was a floating-point inequality comparison, don't do
12886 anything. */
12890 }
12892 /* Convert A ? 1 : 0 to simply A. */
12897 /* If we try to convert OP0 to our type, the
12898 call to fold will try to move the conversion inside
12899 a COND, which will recurse. In that case, the COND_EXPR
12900 is probably the best choice, so leave it alone. */
12904 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12905 over COND_EXPR in cases such as floating point comparisons. */
12914 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12919 {
12920 /* sign_bit_p looks through both zero and sign extensions,
12921 but for this optimization only sign extensions are
12922 usable. */
12925 {
12928 {
12931 }
12933 }
12934 /* sign_bit_p only checks ARG1 bits within A's precision.
12935 If <sign bit of A> has wider type than A, bits outside
12936 of A's precision in <sign bit of A> need to be checked.
12937 If they are all 0, this optimization needs to be done
12938 in unsigned A's type, if they are all 1 in signed A's type,
12939 otherwise this can't be done. */
12945 {
12947 tree tem_type;
12960 {
12963 }
12965 {
12968 }
12969 else
12971 }
12974 return
12980 arg1)));
12981 }
12983 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12984 already handled above. */
12989 {
12999 op1);
13000 }
13002 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13003 is probably obsolete because the first operand should be a
13004 truth value (that's why we have the two cases above), but let's
13005 leave it in until we can confirm this for all front-ends. */
13013 /* operand_equal_p compares just value, not precision, so e.g.
13014 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13015 second operand 32-bit -128, which is not a power of two (or vice
13016 versa. */
13020 /* Disable the transformations below for vectors, since
13021 fold_binary_op_with_conditional_arg may undo them immediately,
13022 yielding an infinite loop. */
13026 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13035 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13040 {
13042 /* Only perform transformation if ARG0 is easily inverted. */
13046 ? BIT_IOR_EXPR
13049 op1);
13050 }
13052 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13057 {
13059 /* Only perform transformation if ARG0 is easily inverted. */
13065 op2);
13066 }
13068 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13080 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13081 of fold_ternary on them. */
13091 {
13093 unsigned HOST_WIDE_INT width
13104 {
13109 {
13111 {
13116 }
13122 }
13123 }
13124 }
13126 /* On constants we can use native encode/interpret to constant
13127 fold (nearly) all BIT_FIELD_REFs. */
13133 {
13136 /* Limit us to a reasonable amount of work. To relax the
13137 other limitations we need bit-shifting of the buffer
13138 and rounding up the size. */
13142 {
13144 unsigned HOST_WIDE_INT len
13149 {
13154 }
13155 }
13156 }
13161 /* Perform constant folding of BIT_INSERT_EXPR. */
13165 {
13166 /* Build a vector of integers from the tree mask. */
13167 vec_perm_builder builder;
13171 /* Create a vec_perm_indices for the integer vector. */
13176 }
13180 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13183 {
13189 wide_int tem2
13193 }
13198 {
13200 unsigned HOST_WIDE_INT elsize
13203 {
13209 {
13215 }
13216 }
13217 }
13223 }
13225 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13226 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13227 constructor element index of the value returned. If the element is
13228 not found NULL_TREE is returned and *CTOR_IDX is updated to
13229 the index of the element after the ACCESS_INDEX position (which
13230 may be outside of the CTOR array). */
13232 tree
13235 {
13241 {
13244 {
13245 /* Static constructors for variably sized objects makes no sense. */
13248 /* ??? When it is obvious that the range is signed, treat it so. */
13253 {
13255 low_bound
13257 SIGNED);
13258 }
13259 else
13260 {
13263 }
13264 }
13265 }
13269 index_sgn);
13281 {
13282 /* Array constructor might explicitly set index, or specify a range,
13283 or leave index NULL meaning that it is next index after previous
13284 one. */
13286 {
13288 max_index = index
13290 else
13291 {
13294 index_sgn);
13295 max_index
13297 index_sgn);
13299 }
13300 }
13302 {
13308 }
13309 else
13312 /* Do we have match? */
13314 {
13316 {
13320 }
13321 }
13323 /* We're past the element we search for. Note during parsing
13324 the elements might not be sorted.
13325 ??? We should use a binary search and a flag on the
13326 CONSTRUCTOR as to whether elements are sorted in declaration
13327 order. */
13329 }
13333 }
13335 /* Perform constant folding and related simplification of EXPR.
13336 The related simplifications include x*1 => x, x*0 => 0, etc.,
13337 and application of the associative law.
13338 NOP_EXPR conversions may be removed freely (as long as we
13339 are careful not to change the type of the overall expression).
13340 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13341 but we can constant-fold them if they have constant operands. */
13343 #ifdef ENABLE_FOLD_CHECKING
13344 # define fold(x) fold_1 (x)
13346 static
13347 #endif
13348 tree
13350 {
13354 tree tem;
13357 /* Return right away if a constant. */
13361 /* CALL_EXPR-like objects with variable numbers of operands are
13362 treated specially. */
13364 {
13366 {
13369 }
13371 }
13374 {
13379 {
13397 }
13398 }
13401 {
13403 {
13410 {
13415 }
13418 }
13420 /* Return a VECTOR_CST if possible. */
13422 {
13428 tree val;
13434 }
13442 }
13444 #ifdef ENABLE_FOLD_CHECKING
13445 #undef fold
13452 /* When --enable-checking=fold, compute a digest of expr before
13453 and after actual fold call to see if fold did not accidentally
13454 change original expr. */
13456 tree
13458 {
13459 tree ret;
13479 }
13481 void
13483 {
13494 }
13496 static void
13498 {
13500 }
13502 static void
13505 {
13511 recursive_label:
13521 {
13522 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13530 }
13538 {
13539 /* Allow these fields to be modified. */
13540 tree tmp;
13551 {
13554 }
13555 }
13557 {
13558 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13559 that and change builtins.cc etc. instead - see PR89543. */
13565 }
13576 {
13579 {
13595 }
13599 {
13612 }
13629 {
13635 }
13638 {
13640 {
13643 }
13645 }
13656 {
13659 }
13667 }
13668 }
13670 /* Helper function for outputting the checksum of a tree T. When
13671 debugging with gdb, you can "define mynext" to be "next" followed
13672 by "call debug_fold_checksum (op0)", then just trace down till the
13673 outputs differ. */
13675 DEBUG_FUNCTION void
13677 {
13692 }
13694 #endif
13696 /* Fold a unary tree expression with code CODE of type TYPE with an
13697 operand OP0. LOC is the location of the resulting expression.
13698 Return a folded expression if successful. Otherwise, return a tree
13699 expression with code CODE of type TYPE with an operand OP0. */
13701 tree
13704 {
13705 tree tem;
13706 #ifdef ENABLE_FOLD_CHECKING
13715 #endif
13721 #ifdef ENABLE_FOLD_CHECKING
13728 #endif
13730 }
13732 /* Fold a binary tree expression with code CODE of type TYPE with
13733 operands OP0 and OP1. LOC is the location of the resulting
13734 expression. Return a folded expression if successful. Otherwise,
13735 return a tree expression with code CODE of type TYPE with operands
13736 OP0 and OP1. */
13738 tree
13741 MEM_STAT_DECL)
13742 {
13743 tree tem;
13744 #ifdef ENABLE_FOLD_CHECKING
13761 #endif
13767 #ifdef ENABLE_FOLD_CHECKING
13782 #endif
13784 }
13786 /* Fold a ternary tree expression with code CODE of type TYPE with
13787 operands OP0, OP1, and OP2. Return a folded expression if
13788 successful. Otherwise, return a tree expression with code CODE of
13789 type TYPE with operands OP0, OP1, and OP2. */
13791 tree
13794 {
13795 tree tem;
13796 #ifdef ENABLE_FOLD_CHECKING
13820 #endif
13827 #ifdef ENABLE_FOLD_CHECKING
13850 #endif
13852 }
13854 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13855 arguments in ARGARRAY, and a null static chain.
13856 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13857 of type TYPE from the given operands as constructed by build_call_array. */
13859 tree
13862 {
13863 tree tem;
13864 #ifdef ENABLE_FOLD_CHECKING
13883 #endif
13889 #ifdef ENABLE_FOLD_CHECKING
13905 #endif
13907 }
13909 /* Perform constant folding and related simplification of initializer
13910 expression EXPR. These behave identically to "fold_buildN" but ignore
13911 potential run-time traps and exceptions that fold must preserve. */
13913 #define START_FOLD_INIT \
13914 int saved_signaling_nans = flag_signaling_nans;\
13915 int saved_trapping_math = flag_trapping_math;\
13916 int saved_rounding_math = flag_rounding_math;\
13917 int saved_trapv = flag_trapv;\
13918 int saved_folding_initializer = folding_initializer;\
13919 flag_signaling_nans = 0;\
13920 flag_trapping_math = 0;\
13921 flag_rounding_math = 0;\
13922 flag_trapv = 0;\
13923 folding_initializer = 1;
13925 #define END_FOLD_INIT \
13926 flag_signaling_nans = saved_signaling_nans;\
13927 flag_trapping_math = saved_trapping_math;\
13928 flag_rounding_math = saved_rounding_math;\
13929 flag_trapv = saved_trapv;\
13930 folding_initializer = saved_folding_initializer;
13932 tree
13934 {
13935 tree result;
13936 START_FOLD_INIT;
13940 END_FOLD_INIT;
13942 }
13944 tree
13947 {
13948 tree result;
13949 START_FOLD_INIT;
13953 END_FOLD_INIT;
13955 }
13957 tree
13960 {
13961 tree result;
13962 START_FOLD_INIT;
13966 END_FOLD_INIT;
13968 }
13970 tree
13973 {
13974 tree result;
13975 START_FOLD_INIT;
13979 END_FOLD_INIT;
13981 }
13983 tree
13986 {
13987 tree result;
13988 START_FOLD_INIT;
13992 END_FOLD_INIT;
13994 }
13996 #undef START_FOLD_INIT
13997 #undef END_FOLD_INIT
13999 /* Determine if first argument is a multiple of second argument. Return 0 if
14000 it is not, or we cannot easily determined it to be.
14002 An example of the sort of thing we care about (at this point; this routine
14003 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14004 fold cases do now) is discovering that
14006 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14008 is a multiple of
14010 SAVE_EXPR (J * 8)
14012 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14014 This code also handles discovering that
14016 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14018 is a multiple of 8 so we don't have to worry about dealing with a
14019 possible remainder.
14021 Note that we *look* inside a SAVE_EXPR only to determine how it was
14022 calculated; it is not safe for fold to do much of anything else with the
14023 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14024 at run time. For example, the latter example above *cannot* be implemented
14025 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14026 evaluation time of the original SAVE_EXPR is not necessarily the same at
14027 the time the new expression is evaluated. The only optimization of this
14028 sort that would be valid is changing
14030 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14032 divided by 8 to
14034 SAVE_EXPR (I) * SAVE_EXPR (J)
14036 (where the same SAVE_EXPR (J) is used in the original and the
14037 transformed version).
14039 NOWRAP specifies whether all outer operations in TYPE should
14040 be considered not wrapping. Any type conversion within TOP acts
14041 as a barrier and we will fall back to NOWRAP being false.
14042 NOWRAP is mostly used to treat expressions in TYPE_SIZE and friends
14043 as not wrapping even though they are generally using unsigned arithmetic. */
14045 int
14047 {
14058 {
14060 /* Bitwise and provides a power of two multiple. If the mask is
14061 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14068 /* If the multiplication can wrap we cannot recurse further unless
14069 the bottom is a power of two which is where wrapping does not
14070 matter. */
14076 {
14082 {
14085 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14087 {
14091 {
14094 }
14095 }
14097 }
14098 }
14103 /* Handle X << CST as X * (1 << CST) and only process the constant. */
14105 {
14108 {
14109 wide_int mul_op
14113 nowrap);
14114 }
14115 }
14120 /* If the addition or subtraction can wrap we cannot recurse further
14121 unless bottom is a power of two which is where wrapping does not
14122 matter. */
14128 /* Handle cases like op0 + 0xfffffffd as op0 - 3 if the expression has
14129 unsigned type. For example, (X / 3) + 0xfffffffd is multiple of 3,
14130 but 0xfffffffd is not. */
14133 && nowrap
14138 /* It is impossible to prove if op0 +- op1 is multiple of bottom
14139 precisely, so be conservative here checking if both op0 and op1
14140 are multiple of bottom. Note we check the second operand first
14141 since it's usually simpler. */
14145 CASE_CONVERT:
14146 /* Can't handle conversions from non-integral or wider integral type. */
14151 /* NOWRAP only extends to operations in the outermost type so
14152 make sure to strip it off here. */
14167 SIGNED);
14173 {
14176 /* Check for special cases to see if top is defined as multiple
14177 of bottom:
14179 top = (X & ~(bottom - 1) ; bottom is power of 2
14181 or
14183 Y = X % bottom
14184 top = X - Y. */
14203 }
14205 /* fall through */
14213 }
14214 }
14216 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14217 This function returns true for integer expressions, and returns
14218 false if uncertain. */
14220 bool
14222 {
14227 {
14250 {
14251 CASE_CFN_FABS:
14252 CASE_CFN_FABS_FN:
14254 CASE_CFN_FMAX:
14255 CASE_CFN_FMAX_FN:
14256 CASE_CFN_FMIN:
14257 CASE_CFN_FMIN_FN:
14262 }
14266 }
14267 }
14269 /* Return true if expression X evaluates to an infinity.
14270 This function returns false for integer expressions. */
14272 bool
14274 {
14278 {
14291 }
14292 }
14294 /* Return true if expression X could evaluate to an infinity.
14295 This function returns false for integer expressions, and returns
14296 true if uncertain. */
14298 bool
14300 {
14304 {
14317 }
14318 }
14320 /* Return true if expression X evaluates to a signaling NaN.
14321 This function returns false for integer expressions. */
14323 bool
14325 {
14329 {
14340 }
14341 }
14343 /* Return true if expression X could evaluate to a signaling NaN.
14344 This function returns false for integer expressions, and returns
14345 true if uncertain. */
14347 bool
14349 {
14353 {
14373 {
14374 CASE_CFN_FABS:
14375 CASE_CFN_FABS_FN:
14377 CASE_CFN_FMAX:
14378 CASE_CFN_FMAX_FN:
14379 CASE_CFN_FMIN:
14380 CASE_CFN_FMIN_FN:
14385 }
14388 }
14389 }
14391 /* Return true if expression X evaluates to a NaN.
14392 This function returns false for integer expressions. */
14394 bool
14396 {
14400 {
14411 }
14412 }
14414 /* Return true if expression X could evaluate to a NaN.
14415 This function returns false for integer expressions, and returns
14416 true if uncertain. */
14418 bool
14420 {
14424 {
14449 {
14450 CASE_CFN_FABS:
14451 CASE_CFN_FABS_FN:
14453 CASE_CFN_FMAX:
14454 CASE_CFN_FMAX_FN:
14455 CASE_CFN_FMIN:
14456 CASE_CFN_FMIN_FN:
14461 }
14464 }
14465 }
14467 /* Return true if expression X could evaluate to -0.0.
14468 This function returns true if uncertain. */
14470 bool
14472 {
14476 {
14491 {
14492 CASE_CFN_FABS:
14493 CASE_CFN_FABS_FN:
14497 }
14500 }
14501 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14502 * but currently those predicates require tree and not const_tree. */
14504 }
14506 #define tree_expr_nonnegative_warnv_p(X, Y) \
14509 #define RECURSE(X) \
14510 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14512 /* Return true if CODE or TYPE is known to be non-negative. */
14514 static bool
14516 {
14519 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14520 have a signed:1 type (where the value is -1 and 0). */
14523 }
14525 /* Return true if (CODE OP0) is known to be non-negative. If the return
14526 value is based on the assumption that signed overflow is undefined,
14527 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14528 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14530 bool
14533 {
14538 {
14540 /* We can't return 1 if flag_wrapv is set because
14541 ABS_EXPR<INT_MIN> = INT_MIN. */
14545 {
14548 }
14556 CASE_CONVERT:
14557 {
14562 {
14566 {
14570 }
14571 }
14573 {
14579 }
14580 }
14585 }
14587 /* We don't know sign of `t', so be conservative and return false. */
14589 }
14591 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14592 value is based on the assumption that signed overflow is undefined,
14593 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14594 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14596 bool
14600 {
14605 {
14611 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14612 both unsigned and at least 2 bits shorter than the result. */
14616 {
14621 {
14625 }
14626 }
14631 {
14632 /* x * x is always non-negative for floating point x
14633 or without overflow. */
14636 {
14641 }
14642 }
14644 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14645 both unsigned and their total bits is shorter than the result. */
14649 {
14668 {
14678 }
14679 }
14686 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14687 things. */
14712 }
14714 /* We don't know sign of `t', so be conservative and return false. */
14716 }
14718 /* Return true if T is known to be non-negative. If the return
14719 value is based on the assumption that signed overflow is undefined,
14720 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14721 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14723 bool
14725 {
14730 {
14744 /* Limit the depth of recursion to avoid quadratic behavior.
14745 This is expected to catch almost all occurrences in practice.
14746 If this code misses important cases that unbounded recursion
14747 would not, passes that need this information could be revised
14748 to provide it through dataflow propagation. */
14756 }
14757 }
14759 /* Return true if T is known to be non-negative. If the return
14760 value is based on the assumption that signed overflow is undefined,
14761 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14762 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14764 bool
14767 {
14769 {
14770 CASE_CFN_ACOS:
14771 CASE_CFN_ACOS_FN:
14772 CASE_CFN_ACOSH:
14773 CASE_CFN_ACOSH_FN:
14774 CASE_CFN_CABS:
14775 CASE_CFN_CABS_FN:
14776 CASE_CFN_COSH:
14777 CASE_CFN_COSH_FN:
14778 CASE_CFN_ERFC:
14779 CASE_CFN_ERFC_FN:
14780 CASE_CFN_EXP:
14781 CASE_CFN_EXP_FN:
14782 CASE_CFN_EXP10:
14783 CASE_CFN_EXP2:
14784 CASE_CFN_EXP2_FN:
14785 CASE_CFN_FABS:
14786 CASE_CFN_FABS_FN:
14787 CASE_CFN_FDIM:
14788 CASE_CFN_FDIM_FN:
14789 CASE_CFN_HYPOT:
14790 CASE_CFN_HYPOT_FN:
14791 CASE_CFN_POW10:
14792 CASE_CFN_FFS:
14793 CASE_CFN_PARITY:
14794 CASE_CFN_POPCOUNT:
14795 CASE_CFN_CLZ:
14796 CASE_CFN_CLRSB:
14801 /* Always true. */
14804 CASE_CFN_SQRT:
14805 CASE_CFN_SQRT_FN:
14806 /* sqrt(-0.0) is -0.0. */
14811 CASE_CFN_ASINH:
14812 CASE_CFN_ASINH_FN:
14813 CASE_CFN_ATAN:
14814 CASE_CFN_ATAN_FN:
14815 CASE_CFN_ATANH:
14816 CASE_CFN_ATANH_FN:
14817 CASE_CFN_CBRT:
14818 CASE_CFN_CBRT_FN:
14819 CASE_CFN_CEIL:
14820 CASE_CFN_CEIL_FN:
14821 CASE_CFN_ERF:
14822 CASE_CFN_ERF_FN:
14823 CASE_CFN_EXPM1:
14824 CASE_CFN_EXPM1_FN:
14825 CASE_CFN_FLOOR:
14826 CASE_CFN_FLOOR_FN:
14827 CASE_CFN_FMOD:
14828 CASE_CFN_FMOD_FN:
14829 CASE_CFN_FREXP:
14830 CASE_CFN_FREXP_FN:
14831 CASE_CFN_ICEIL:
14832 CASE_CFN_IFLOOR:
14833 CASE_CFN_IRINT:
14834 CASE_CFN_IROUND:
14835 CASE_CFN_LCEIL:
14836 CASE_CFN_LDEXP:
14837 CASE_CFN_LFLOOR:
14838 CASE_CFN_LLCEIL:
14839 CASE_CFN_LLFLOOR:
14840 CASE_CFN_LLRINT:
14841 CASE_CFN_LLRINT_FN:
14842 CASE_CFN_LLROUND:
14843 CASE_CFN_LLROUND_FN:
14844 CASE_CFN_LRINT:
14845 CASE_CFN_LRINT_FN:
14846 CASE_CFN_LROUND:
14847 CASE_CFN_LROUND_FN:
14848 CASE_CFN_MODF:
14849 CASE_CFN_MODF_FN:
14850 CASE_CFN_NEARBYINT:
14851 CASE_CFN_NEARBYINT_FN:
14852 CASE_CFN_RINT:
14853 CASE_CFN_RINT_FN:
14854 CASE_CFN_ROUND:
14855 CASE_CFN_ROUND_FN:
14856 CASE_CFN_ROUNDEVEN:
14857 CASE_CFN_ROUNDEVEN_FN:
14858 CASE_CFN_SCALB:
14859 CASE_CFN_SCALBLN:
14860 CASE_CFN_SCALBLN_FN:
14861 CASE_CFN_SCALBN:
14862 CASE_CFN_SCALBN_FN:
14863 CASE_CFN_SIGNBIT:
14864 CASE_CFN_SIGNIFICAND:
14865 CASE_CFN_SINH:
14866 CASE_CFN_SINH_FN:
14867 CASE_CFN_TANH:
14868 CASE_CFN_TANH_FN:
14869 CASE_CFN_TRUNC:
14870 CASE_CFN_TRUNC_FN:
14871 /* True if the 1st argument is nonnegative. */
14874 CASE_CFN_FMAX:
14875 CASE_CFN_FMAX_FN:
14876 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14877 things. In the presence of sNaNs, we're only guaranteed to be
14878 non-negative if both operands are non-negative. In the presence
14879 of qNaNs, we're non-negative if either operand is non-negative
14880 and can't be a qNaN, or if both operands are non-negative. */
14889 CASE_CFN_FMIN:
14890 CASE_CFN_FMIN_FN:
14891 /* True if the 1st AND 2nd arguments are nonnegative. */
14894 CASE_CFN_COPYSIGN:
14895 CASE_CFN_COPYSIGN_FN:
14896 /* True if the 2nd argument is nonnegative. */
14899 CASE_CFN_POWI:
14900 /* True if the 1st argument is nonnegative or the second
14901 argument is an even integer. */
14907 CASE_CFN_POW:
14908 CASE_CFN_POW_FN:
14909 /* True if the 1st argument is nonnegative or the second
14910 argument is an even integer valued real. */
14912 {
14913 REAL_VALUE_TYPE c;
14914 HOST_WIDE_INT n;
14919 {
14920 REAL_VALUE_TYPE cint;
14924 }
14925 }
14930 }
14932 }
14934 /* Return true if T is known to be non-negative. If the return
14935 value is based on the assumption that signed overflow is undefined,
14936 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14937 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14939 static bool
14941 {
14947 {
14949 {
14953 /* If the initializer is non-void, then it's a normal expression
14954 that will be assigned to the slot. */
14958 /* Otherwise, the initializer sets the slot in some way. One common
14959 way is an assignment statement at the end of the initializer. */
14961 {
14969 else
14971 }
14977 }
14980 {
14986 arg0,
14987 arg1,
14989 }
15002 }
15003 }
15005 #undef RECURSE
15006 #undef tree_expr_nonnegative_warnv_p
15008 /* Return true if T is known to be non-negative. If the return
15009 value is based on the assumption that signed overflow is undefined,
15010 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15011 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15013 bool
15015 {
15022 {
15044 }
15047 {
15072 }
15073 }
15075 /* Return true if `t' is known to be non-negative. Handle warnings
15076 about undefined signed overflow. */
15078 bool
15080 {
15087 "determining that expression is always "
15089 WARN_STRICT_OVERFLOW_MISC);
15091 }
15094 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15095 For floating point we further ensure that T is not denormal.
15096 Similar logic is present in nonzero_address in rtlanal.h.
15098 If the return value is based on the assumption that signed overflow
15099 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15100 change *STRICT_OVERFLOW_P. */
15102 bool
15105 {
15107 {
15110 strict_overflow_p);
15113 {
15119 strict_overflow_p));
15120 }
15125 strict_overflow_p);
15129 }
15132 }
15134 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15135 For floating point we further ensure that T is not denormal.
15136 Similar logic is present in nonzero_address in rtlanal.h.
15138 If the return value is based on the assumption that signed overflow
15139 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15140 change *STRICT_OVERFLOW_P. */
15142 bool
15144 tree type,
15145 tree op0,
15147 {
15150 {
15154 {
15155 /* With the presence of negative values it is hard
15156 to say something. */
15163 /* One of operands must be positive and the other non-negative. */
15164 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15165 overflows, on a twos-complement machine the sum of two
15166 nonnegative numbers can never be zero. */
15168 strict_overflow_p)
15170 strict_overflow_p));
15171 }
15176 {
15178 strict_overflow_p)
15180 strict_overflow_p))
15181 {
15184 }
15185 }
15194 {
15197 }
15204 {
15208 /* When both operands are nonzero, then MAX must be too. */
15210 strict_overflow_p))
15213 /* MAX where operand 0 is positive is positive. */
15215 strict_overflow_p);
15216 }
15217 /* MAX where operand 1 is positive is positive. */
15222 {
15226 }
15231 strict_overflow_p)
15233 strict_overflow_p));
15237 }
15240 }
15242 /* Return true when T is an address and is known to be nonzero.
15243 For floating point we further ensure that T is not denormal.
15244 Similar logic is present in nonzero_address in rtlanal.h.
15246 If the return value is based on the assumption that signed overflow
15247 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15248 change *STRICT_OVERFLOW_P. */
15250 bool
15252 {
15255 {
15260 {
15272 /* For objects in symbol table check if we know they are non-zero.
15273 Don't do anything for variables and functions before symtab is built;
15274 it is quite possible that they will be declared weak later. */
15279 /* Constants are never weak. */
15284 }
15292 {
15296 }
15306 }
15308 }
15310 #define integer_valued_real_p(X) \
15313 #define RECURSE(X) \
15314 ((integer_valued_real_p) (X, depth + 1))
15316 /* Return true if the floating point result of (CODE OP0) has an
15317 integer value. We also allow +Inf, -Inf and NaN to be considered
15318 integer values. Return false for signaling NaN.
15320 DEPTH is the current nesting depth of the query. */
15322 bool
15324 {
15326 {
15333 CASE_CONVERT:
15334 {
15341 }
15345 }
15347 }
15349 /* Return true if the floating point result of (CODE OP0 OP1) has an
15350 integer value. We also allow +Inf, -Inf and NaN to be considered
15351 integer values. Return false for signaling NaN.
15353 DEPTH is the current nesting depth of the query. */
15355 bool
15357 {
15359 {
15369 }
15371 }
15373 /* Return true if the floating point result of calling FNDECL with arguments
15374 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15375 considered integer values. Return false for signaling NaN. If FNDECL
15376 takes fewer than 2 arguments, the remaining ARGn are null.
15378 DEPTH is the current nesting depth of the query. */
15380 bool
15382 {
15384 {
15385 CASE_CFN_CEIL:
15386 CASE_CFN_CEIL_FN:
15387 CASE_CFN_FLOOR:
15388 CASE_CFN_FLOOR_FN:
15389 CASE_CFN_NEARBYINT:
15390 CASE_CFN_NEARBYINT_FN:
15391 CASE_CFN_RINT:
15392 CASE_CFN_RINT_FN:
15393 CASE_CFN_ROUND:
15394 CASE_CFN_ROUND_FN:
15395 CASE_CFN_ROUNDEVEN:
15396 CASE_CFN_ROUNDEVEN_FN:
15397 CASE_CFN_TRUNC:
15398 CASE_CFN_TRUNC_FN:
15401 CASE_CFN_FMIN:
15402 CASE_CFN_FMIN_FN:
15403 CASE_CFN_FMAX:
15404 CASE_CFN_FMAX_FN:
15409 }
15411 }
15413 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15414 has an integer value. We also allow +Inf, -Inf and NaN to be
15415 considered integer values. Return false for signaling NaN.
15417 DEPTH is the current nesting depth of the query. */
15419 bool
15421 {
15423 {
15431 /* Limit the depth of recursion to avoid quadratic behavior.
15432 This is expected to catch almost all occurrences in practice.
15433 If this code misses important cases that unbounded recursion
15434 would not, passes that need this information could be revised
15435 to provide it through dataflow propagation. */
15439 depth));
15443 }
15445 }
15447 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15448 has an integer value. We also allow +Inf, -Inf and NaN to be
15449 considered integer values. Return false for signaling NaN.
15451 DEPTH is the current nesting depth of the query. */
15453 static bool
15455 {
15457 {
15468 }
15470 }
15472 #undef RECURSE
15473 #undef integer_valued_real_p
15475 /* Return true if the floating point expression T has an integer value.
15476 We also allow +Inf, -Inf and NaN to be considered integer values.
15477 Return false for signaling NaN.
15479 DEPTH is the current nesting depth of the query. */
15481 bool
15483 {
15491 {
15507 }
15510 {
15516 {
15525 }
15529 }
15530 }
15532 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15533 attempt to fold the expression to a constant without modifying TYPE,
15534 OP0 or OP1.
15536 If the expression could be simplified to a constant, then return
15537 the constant. If the expression would not be simplified to a
15538 constant, then return NULL_TREE. */
15540 tree
15542 {
15545 }
15547 /* Given the components of a unary expression CODE, TYPE and OP0,
15548 attempt to fold the expression to a constant without modifying
15549 TYPE or OP0.
15551 If the expression could be simplified to a constant, then return
15552 the constant. If the expression would not be simplified to a
15553 constant, then return NULL_TREE. */
15555 tree
15557 {
15560 }
15562 /* If EXP represents referencing an element in a constant string
15563 (either via pointer arithmetic or array indexing), return the
15564 tree representing the value accessed, otherwise return NULL. */
15566 tree
15568 {
15572 {
15574 tree index;
15575 tree string;
15580 else
15581 {
15585 /* Optimize the special-case of a zero lower bound.
15587 We convert the low_bound to sizetype to avoid some problems
15588 with constant folding. (E.g. suppose the lower bound is 1,
15589 and its mode is QI. Without the conversion,l (ARRAY
15590 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15591 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15597 }
15599 scalar_int_mode char_mode;
15611 }
15613 }
15615 /* Folds a read from vector element at IDX of vector ARG. */
15617 tree
15619 {
15624 {
15628 {
15635 }
15636 }
15638 }
15640 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15641 an integer constant, real, or fixed-point constant.
15643 TYPE is the type of the result. */
15645 static tree
15647 {
15651 {
15657 {
15658 FIXED_VALUE_TYPE f;
15663 /* Propagate overflow flags. */
15667 }
15671 {
15678 }
15681 }
15684 }
15686 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15687 an integer constant or real constant.
15689 TYPE is the type of the result. */
15691 tree
15693 {
15697 {
15699 {
15700 /* If the value is unsigned or non-negative, then the absolute value
15701 is the same as the ordinary value. */
15705 ;
15707 /* If the value is negative, then the absolute value is
15708 its negation. */
15709 else
15712 /* Force to the destination type, set TREE_OVERFLOW for signed
15713 TYPE only. */
15715 }
15721 else
15727 }
15730 }
15732 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15733 constant. TYPE is the type of the result. */
15735 static tree
15737 {
15741 }
15743 /* Given CODE, a relational operator, the target type, TYPE and two
15744 constant operands OP0 and OP1, return the result of the
15745 relational operation. If the result is not a compile time
15746 constant, then return NULL_TREE. */
15748 static tree
15750 {
15753 /* From here on, the only cases we handle are when the result is
15754 known to be a constant. */
15757 {
15761 /* Handle the cases where either operand is a NaN. */
15763 {
15765 {
15793 }
15796 }
15799 }
15802 {
15806 }
15808 /* Handle equality/inequality of complex constants. */
15810 {
15821 else
15823 }
15826 {
15828 {
15829 /* Have vector comparison with scalar boolean result. */
15837 {
15845 }
15847 }
15848 tree_vector_builder elts;
15853 {
15866 }
15869 }
15871 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15873 To compute GT, swap the arguments and do LT.
15874 To compute GE, do LT and invert the result.
15875 To compute LE, swap the arguments, do LT and invert the result.
15876 To compute NE, do EQ and invert the result.
15878 Therefore, the code below must handle only EQ and LT. */
15881 {
15884 }
15886 /* Note that it is safe to invert for real values here because we
15887 have already handled the one case that it matters. */
15891 {
15894 }
15896 /* Compute a result for LT or EQ if args permit;
15897 Otherwise return T. */
15899 {
15902 else
15904 }
15905 else
15911 }
15913 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15914 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15915 itself. */
15917 tree
15919 {
15920 /* If the expression does not have side effects then we don't have to wrap
15921 it with a cleanup point expression. */
15925 /* If the expression is a return, check to see if the expression inside the
15926 return has no side effects or the right hand side of the modify expression
15927 inside the return. If either don't have side effects set we don't need to
15928 wrap the expression in a cleanup point expression. Note we don't check the
15929 left hand side of the modify because it should always be a return decl. */
15931 {
15938 }
15941 }
15943 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15944 of an indirection through OP0, or NULL_TREE if no simplification is
15945 possible. */
15947 tree
15949 {
15951 tree subtype;
15952 poly_uint64 const_op01;
15961 {
15965 /* *&CONST_DECL -> to the value of the const decl. */
15968 /* *&p => p; make sure to handle *&"str"[cst] here. */
15970 {
15974 else
15976 }
15977 /* *(foo *)&fooarray => fooarray[0] */
15980 && (!in_gimple_form
15982 {
15992 }
15993 /* *(foo *)&complexfoo => __real__ complexfoo */
15997 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
16000 {
16004 index);
16005 }
16006 }
16010 {
16016 {
16017 tree op00type;
16021 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
16024 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
16025 but we want to treat offsets with MSB set as negative.
16026 For the code below negative offsets are invalid and
16027 TYPE_SIZE of the element is something unsigned, so
16028 check whether op01 fits into poly_int64, which implies
16029 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
16030 then just use poly_uint64 because we want to treat the
16031 value as unsigned. */
16033 {
16035 poly_uint64 max_offset
16039 {
16044 }
16045 }
16046 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
16049 {
16051 const_op01))
16053 }
16054 /* ((foo *)&fooarray)[1] => fooarray[1] */
16057 {
16066 {
16071 }
16072 }
16073 }
16074 }
16076 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16079 && (!in_gimple_form
16081 {
16082 tree type_domain;
16092 NULL_TREE);
16093 }
16096 }
16098 /* Builds an expression for an indirection through T, simplifying some
16099 cases. */
16101 tree
16103 {
16111 }
16113 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16115 tree
16117 {
16122 else
16124 }
16126 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16127 whose result is ignored. The type of the returned tree need not be
16128 the same as the original expression. */
16130 tree
16132 {
16138 {
16149 else
16155 {
16171 }
16176 }
16177 }
16179 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16181 tree
16183 {
16189 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16190 have to do anything. Only do this when we are not given a const,
16191 because in that case, this check is more expensive than just
16192 doing it. */
16194 {
16199 }
16201 /* If divisor is a power of two, simplify this to bit manipulation. */
16203 {
16205 {
16219 }
16220 else
16221 {
16222 tree t;
16228 }
16229 }
16230 else
16231 {
16236 }
16239 }
16241 /* Likewise, but round down. */
16243 tree
16245 {
16252 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16253 have to do anything. Only do this when we are not given a const,
16254 because in that case, this check is more expensive than just
16255 doing it. */
16257 {
16262 }
16264 /* If divisor is a power of two, simplify this to bit manipulation. */
16266 {
16267 tree t;
16271 }
16272 else
16273 {
16278 }
16281 }
16283 /* Returns the pointer to the base of the object addressed by EXP and
16284 extracts the information about the offset of the access, storing it
16285 to PBITPOS and POFFSET. */
16287 static tree
16290 {
16291 tree core;
16292 machine_mode mode;
16294 poly_int64 bitsize;
16303 {
16308 }
16310 {
16316 {
16317 poly_offset_int tem
16323 }
16324 }
16325 else
16326 {
16330 }
16333 }
16335 /* Returns true if addresses of E1 and E2 differ by a constant, false
16336 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16338 bool
16340 {
16355 {
16365 }
16367 {
16368 /* If only one of the offsets is non-constant, the difference cannot
16369 be a constant. */
16371 }
16372 else
16377 }
16379 /* Return OFF converted to a pointer offset type suitable as offset for
16380 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16381 tree
16383 {
16387 }
16389 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16390 tree
16392 {
16395 }
16397 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16398 tree
16400 {
16403 }
16405 /* Return a pointer to a NUL-terminated string containing the sequence
16406 of bytes corresponding to the representation of the object referred to
16407 by SRC (or a subsequence of such bytes within it if SRC is a reference
16408 to an initialized constant array plus some constant offset).
16409 Set *STRSIZE the number of bytes in the constant sequence including
16410 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16411 where A is the array that stores the constant sequence that SRC points
16412 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16413 need not point to a string or even an array of characters but may point
16414 to an object of any type. */
16418 {
16419 /* The offset into the array A storing the string, and A's byte size. */
16420 tree offset_node;
16421 tree mem_size;
16428 else
16435 {
16438 else
16440 }
16445 /* ARRAY_SIZE is the byte size of the array the constant sequence
16446 is stored in and equal to sizeof A. INIT_BYTES is the number
16447 of bytes in the constant sequence used to initialize the array,
16448 including any embedded NULs as well as the terminating NUL (for
16449 strings), but not including any trailing zeros/NULs past
16450 the terminating one appended implicitly to a string literal to
16451 zero out the remainder of the array it's stored in. For example,
16452 given:
16453 const char a[7] = "abc\0d";
16454 n = strlen (a + 1);
16455 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16456 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16457 is equal to strlen (A) + 1. */
16462 /* Ideally this would turn into a gcc_checking_assert over time. */
16470 {
16471 /* Compute and store the number of characters from the beginning
16472 of the substring at OFFSET to the end, including the terminating
16473 nul. Offsets past the initial length refer to null strings. */
16476 else
16478 }
16479 else
16480 {
16482 /* Support only properly NUL-terminated single byte strings. */
16487 }
16490 }
16492 /* Return a pointer to a NUL-terminated string corresponding to
16493 the expression STR referencing a constant string, possibly
16494 involving a constant offset. Return null if STR either doesn't
16495 reference a constant string or if it involves a nonconstant
16496 offset. */
16500 {
16502 }
16504 /* Given a tree T, compute which bits in T may be nonzero. */
16506 wide_int
16508 {
16510 {
16528 CASE_CONVERT:
16534 {
16539 }
16543 {
16551 }
16555 {
16563 }
16567 }
16570 }
16572 /* Helper function for address compare simplifications in match.pd.
16573 OP0 and OP1 are ADDR_EXPR operands being compared by CODE.
16574 TYPE is the type of comparison operands.
16575 BASE0, BASE1, OFF0 and OFF1 are set by the function.
16576 GENERIC is true if GENERIC folding and false for GIMPLE folding.
16577 Returns 0 if OP0 is known to be unequal to OP1 regardless of OFF{0,1},
16578 1 if bases are known to be equal and OP0 cmp OP1 depends on OFF0 cmp OFF1,
16579 and 2 if unknown. */
16581 int
16585 {
16595 {
16598 }
16600 {
16603 }
16608 /* Punt in GENERIC on variables with value expressions;
16609 the value expressions might point to fields/elements
16610 of other vars etc. */
16616 {
16620 }
16628 /* Assume different STRING_CSTs with the same content will be
16629 merged. */
16638 {
16641 /* If the offsets are equal we can ignore overflow. */
16644 /* Or if we compare using pointers to decls or strings. */
16649 }
16655 /* At this point we know (or assume) the two pointers point at
16656 different objects. */
16660 /* Punt on non-zero offsets from functions. */
16664 /* Or if the bases are neither decls nor string literals. */
16669 /* For initializers, assume addresses of different functions are
16670 different. */
16676 /* Compute whether one address points to the start of one
16677 object and another one to the end of another one. */
16680 {
16683 else
16685 }
16688 else
16689 {
16693 else
16695 }
16697 {
16700 else
16702 }
16705 else
16706 {
16710 else
16712 }
16714 {
16715 /* If one offset is pointing (or could be) to the beginning of one
16716 object and the other is pointing to one past the last byte of the
16717 other object, punt. */
16722 /* If both offsets are the same, there are some cases we know that are
16723 ok. Either if we know they aren't zero, or if we know both sizes
16724 are no zero. */
16730 }
16732 /* At this point, equal is 2 if either one or both pointers are out of
16733 bounds of their object, or one points to start of its object and the
16734 other points to end of its object. This is unspecified behavior
16735 e.g. in C++. Otherwise equal is 0. */
16739 /* When both pointers point to string literals, even when equal is 0,
16740 due to tail merging of string literals the pointers might be the same. */
16742 {
16749 /* If the bytes in the string literals starting at the pointers
16750 differ, the pointers need to be different. */
16755 {
16760 /* If even the bytes in the string literal before the
16761 pointers are the same, the string literals could be
16762 tail merged. */
16764 }
16766 }
16771 /* If this is a pointer comparison, ignore for now even
16772 valid equalities where one pointer is the offset zero
16773 of one object and the other to one past end of another one. */
16777 /* Assume that string literals can't be adjacent to variables
16778 (automatic or global). */
16782 /* Assume that automatic variables can't be adjacent to global
16783 variables. */
16788 }
16790 /* Return the single non-zero element of a CONSTRUCTOR or NULL_TREE. */
16791 tree
16793 {
16802 {
16806 }
16808 }
16810 #if CHECKING_P
16814 /* Helper functions for writing tests of folding trees. */
16816 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16818 static void
16820 tree constant)
16821 {
16823 }
16825 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16826 wrapping WRAPPED_EXPR. */
16828 static void
16830 tree wrapped_expr)
16831 {
16836 }
16838 /* Verify that various arithmetic binary operations are folded
16839 correctly. */
16841 static void
16843 {
16849 /* Addition. */
16850 /* 1 <-- (0 + 1) */
16852 one);
16854 one);
16856 /* (nonlvalue)x <-- (x + 0) */
16858 x);
16860 /* Subtraction. */
16861 /* 0 <-- (x - x) */
16863 zero);
16865 x);
16867 /* Multiplication. */
16868 /* 0 <-- (x * 0) */
16870 zero);
16872 /* (nonlvalue)x <-- (x * 1) */
16874 x);
16875 }
16877 /* Verify that various binary operations on vectors are folded
16878 correctly. */
16880 static void
16882 {
16889 /* Verify equality tests that return a scalar boolean result. */
16902 }
16904 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16906 static void
16908 {
16911 /* This will be 1 if VEC_MODE isn't a vector mode. */
16918 }
16920 /* Run all of the selftests within this file. */
16922 void
16924 {
16928 }