| blob | ea0b43e942d27ea455cd52e017a45a7b593db034 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /*@@ This file should be rewritten to use an arbitrary precision
23 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
24 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
25 @@ The routines that translate from the ap rep should
26 @@ warn if precision et. al. is lost.
27 @@ This would also make life easier when this technology is used
28 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int_wide, size_binop
31 and force_fit_type_double.
33 fold takes a tree as argument and returns a simplified tree.
35 size_binop takes a tree code for an arithmetic operation
36 and two operands that are trees, and produces a tree for the
37 result, assuming the type comes from `sizetype'.
39 size_int takes an integer value, and creates a tree constant
40 with type from `sizetype'.
42 force_fit_type_double takes a constant, an overflowable flag and a
43 prior overflow indicator. It forces the value to fit the type and
44 sets TREE_OVERFLOW.
46 Note: Since the folders get called on non-gimple code as well as
47 gimple code, we need to handle GIMPLE tuples as well as their
48 corresponding tree equivalents. */
68 /* Nonzero if we are folding constants inside an initializer; zero
69 otherwise. */
72 /* The following constants represent a bit based encoding of GCC's
73 comparison operators. This encoding simplifies transformations
74 on relational comparison operators, such as AND and OR. */
92 };
126 tree);
148 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
149 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
150 and SUM1. Then this yields nonzero if overflow occurred during the
151 addition.
153 Overflow occurs if A and B have the same sign, but A and SUM differ in
154 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
155 sign. */
156 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
157 \f
158 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
159 We do that by representing the two-word integer in 4 words, with only
160 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
161 number. The value of the word is LOWPART + HIGHPART * BASE. */
163 #define LOWPART(x) \
164 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
165 #define HIGHPART(x) \
166 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
167 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
169 /* Unpack a two-word integer into 4 words.
170 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
171 WORDS points to the array of HOST_WIDE_INTs. */
173 static void
175 {
180 }
182 /* Pack an array of 4 words into a two-word integer.
183 WORDS points to the array of words.
184 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
186 static void
189 {
192 }
193 \f
194 /* Force the double-word integer L1, H1 to be within the range of the
195 integer type TYPE. Stores the properly truncated and sign-extended
196 double-word integer in *LV, *HV. Returns true if the operation
197 overflows, that is, argument and result are different. */
199 int
202 {
211 else
214 /* Size types *are* sign extended. */
219 /* First clear all bits that are beyond the type's precision. */
221 ;
224 else
225 {
229 }
231 /* Then do sign extension if necessary. */
237 {
238 /* Sign extend top half? */
242 }
244 {
247 }
248 else
249 {
250 /* Sign extend bottom half? */
252 {
255 }
256 }
261 /* If the value didn't fit, signal overflow. */
263 }
265 /* We force the double-int HIGH:LOW to the range of the type TYPE by
266 sign or zero extending it.
267 OVERFLOWABLE indicates if we are interested
268 in overflow of the value, when >0 we are only interested in signed
269 overflow, for <0 we are interested in any overflow. OVERFLOWED
270 indicates whether overflow has already occurred. CONST_OVERFLOWED
271 indicates whether constant overflow has already occurred. We force
272 T's value to be within range of T's type (by setting to 0 or 1 all
273 the bits outside the type's range). We set TREE_OVERFLOWED if,
274 OVERFLOWED is nonzero,
275 or OVERFLOWABLE is >0 and signed overflow occurs
276 or OVERFLOWABLE is <0 and any overflow occurs
277 We return a new tree node for the extended double-int. The node
278 is shared if no overflow flags are set. */
280 tree
284 {
288 /* Size types *are* sign extended. */
295 /* If we need to set overflow flags, return a new unshared node. */
297 {
301 {
308 }
309 }
311 /* Else build a shared node. */
313 }
314 \f
315 /* Add two doubleword integers with doubleword result.
316 Return nonzero if the operation overflows according to UNSIGNED_P.
317 Each argument is given as two `HOST_WIDE_INT' pieces.
318 One argument is L1 and H1; the other, L2 and H2.
319 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
321 int
326 {
328 HOST_WIDE_INT h;
338 else
340 }
342 /* Negate a doubleword integer with doubleword result.
343 Return nonzero if the operation overflows, assuming it's signed.
344 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
345 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
347 int
350 {
352 {
356 }
357 else
358 {
362 }
363 }
364 \f
365 /* Multiply two doubleword integers with doubleword result.
366 Return nonzero if the operation overflows according to UNSIGNED_P.
367 Each argument is given as two `HOST_WIDE_INT' pieces.
368 One argument is L1 and H1; the other, L2 and H2.
369 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
371 int
376 {
391 {
394 {
396 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
398 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
402 }
404 }
409 /* Unsigned overflow is immediate. */
413 /* Check for signed overflow by calculating the signed representation of the
414 top half of the result; it should agree with the low half's sign bit. */
416 {
419 }
421 {
424 }
426 }
427 \f
428 /* Shift the doubleword integer in L1, H1 left by COUNT places
429 keeping only PREC bits of result.
430 Shift right if COUNT is negative.
431 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
432 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
434 void
438 {
442 {
445 }
451 {
452 /* Shifting by the host word size is undefined according to the
453 ANSI standard, so we must handle this as a special case. */
456 }
458 {
461 }
462 else
463 {
467 }
469 /* Sign extend all bits that are beyond the precision. */
477 ;
479 {
482 }
483 else
484 {
488 }
489 }
491 /* Shift the doubleword integer in L1, H1 right by COUNT places
492 keeping only PREC bits of result. COUNT must be positive.
493 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
494 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
496 void
501 {
504 signmask = (arith
512 {
513 /* Shifting by the host word size is undefined according to the
514 ANSI standard, so we must handle this as a special case. */
517 }
519 {
522 }
523 else
524 {
528 }
530 /* Zero / sign extend all bits that are beyond the precision. */
533 {
536 }
538 ;
540 {
543 }
544 else
545 {
549 }
550 }
551 \f
552 /* Rotate the doubleword integer in L1, H1 left by COUNT places
553 keeping only PREC bits of result.
554 Rotate right if COUNT is negative.
555 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
557 void
561 {
573 }
575 /* Rotate the doubleword integer in L1, H1 left by COUNT places
576 keeping only PREC bits of result. COUNT must be positive.
577 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
579 void
583 {
595 }
596 \f
597 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
598 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
599 CODE is a tree code for a kind of division, one of
600 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
601 or EXACT_DIV_EXPR
602 It controls how the quotient is rounded to an integer.
603 Return nonzero if the operation overflows.
604 UNS nonzero says do unsigned division. */
606 int
609 HOST_WIDE_INT hnum_orig,
611 HOST_WIDE_INT hden_orig,
615 {
631 /* Calculate quotient sign and convert operands to unsigned. */
633 {
635 {
637 /* (minimum integer) / (-1) is the only overflow case. */
641 }
643 {
646 }
647 }
652 /* This unsigned division rounds toward zero. */
655 }
659 /* hden != 0 already checked. */
664 }
674 /* Special code for when the divisor < BASE. */
676 {
677 /* hnum != 0 already checked. */
679 {
683 }
684 }
685 else
686 {
687 /* Full double precision division,
688 with thanks to Don Knuth's "Seminumerical Algorithms". */
692 /* Find the highest nonzero divisor digit. */
695 {
698 }
700 /* Insure that the first digit of the divisor is at least BASE/2.
701 This is required by the quotient digit estimation algorithm. */
708 {
712 }
717 {
722 }
723 }
727 /* Main loop */
729 {
730 /* Guess the next quotient digit, quo_est, by dividing the first
731 two remaining dividend digits by the high order quotient digit.
732 quo_est is never low and is at most 2 high. */
739 else
742 /* Refine quo_est so it's usually correct, and at most one high. */
747 quo_est--;
749 /* Try QUO_EST as the quotient digit, by multiplying the
750 divisor by QUO_EST and subtracting from the remaining dividend.
751 Keep in mind that QUO_EST is the I - 1st digit. */
755 {
761 }
763 /* If quo_est was high by one, then num[i] went negative and
764 we need to correct things. */
766 {
767 quo_est--;
770 {
774 }
777 }
779 /* Store the quotient digit. */
781 }
782 }
786 finish_up:
787 /* If result is negative, make it so. */
791 /* Compute trial remainder: rem = num - (quo * den) */
797 {
806 {
807 /* quo = quo - 1; */
810 }
811 else
818 {
821 }
822 else
828 {
834 /* Get absolute values. */
840 /* If (2 * abs (lrem) >= abs (lden)) */
849 {
851 /* quo = quo - 1; */
854 else
855 /* quo = quo + 1; */
858 }
859 else
861 }
866 }
868 /* Compute true remainder: rem = num - (quo * den) */
873 }
875 /* If ARG2 divides ARG1 with zero remainder, carries out the division
876 of type CODE and returns the quotient.
877 Otherwise returns NULL_TREE. */
879 static tree
881 {
891 /* &obj[0] + -128 really should be compiled as &obj[-8] rather than
892 &obj[some_exotic_number]. */
894 {
898 type);
899 }
900 else
911 }
912 \f
913 /* This is nonzero if we should defer warnings about undefined
914 overflow. This facility exists because these warnings are a
915 special case. The code to estimate loop iterations does not want
916 to issue any warnings, since it works with expressions which do not
917 occur in user code. Various bits of cleanup code call fold(), but
918 only use the result if it has certain characteristics (e.g., is a
919 constant); that code only wants to issue a warning if the result is
920 used. */
924 /* If a warning about undefined overflow is deferred, this is the
925 warning. Note that this may cause us to turn two warnings into
926 one, but that is fine since it is sufficient to only give one
927 warning per expression. */
931 /* If a warning about undefined overflow is deferred, this is the
932 level at which the warning should be emitted. */
936 /* Start deferring overflow warnings. We could use a stack here to
937 permit nested calls, but at present it is not necessary. */
939 void
941 {
943 }
945 /* Stop deferring overflow warnings. If there is a pending warning,
946 and ISSUE is true, then issue the warning if appropriate. STMT is
947 the statement with which the warning should be associated (used for
948 location information); STMT may be NULL. CODE is the level of the
949 warning--a warn_strict_overflow_code value. This function will use
950 the smaller of CODE and the deferred code when deciding whether to
951 issue the warning. CODE may be zero to mean to always use the
952 deferred code. */
954 void
956 {
958 location_t locus;
963 {
969 }
980 /* Use the smallest code level when deciding to issue the
981 warning. */
990 else
993 }
995 /* Stop deferring overflow warnings, ignoring any deferred
996 warnings. */
998 void
1000 {
1002 }
1004 /* Whether we are deferring overflow warnings. */
1006 bool
1008 {
1010 }
1012 /* This is called when we fold something based on the fact that signed
1013 overflow is undefined. */
1015 static void
1017 {
1020 {
1023 {
1026 }
1027 }
1030 }
1031 \f
1032 /* Return true if the built-in mathematical function specified by CODE
1033 is odd, i.e. -f(x) == f(-x). */
1035 static bool
1037 {
1039 {
1073 }
1075 }
1077 /* Check whether we may negate an integer constant T without causing
1078 overflow. */
1080 bool
1082 {
1085 tree type;
1095 {
1100 }
1101 else
1106 }
1108 /* Determine whether an expression T can be cheaply negated using
1109 the function negate_expr without introducing undefined overflow. */
1111 static bool
1113 {
1114 tree type;
1123 {
1128 /* Check that -CST will not overflow type. */
1154 /* -(A + B) -> (-B) - A. */
1159 /* -(A + B) -> (-A) - B. */
1163 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
1173 /* Fall through. */
1186 /* In general we can't negate A / B, because if A is INT_MIN and
1187 B is 1, we may turn this into INT_MIN / -1 which is undefined
1188 and actually traps on some architectures. But if overflow is
1189 undefined, we can negate, because - (INT_MIN / 1) is an
1190 overflow. */
1198 /* Negate -((double)float) as (double)(-float). */
1200 {
1204 }
1208 /* Negate -f(x) as f(-x). */
1214 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1216 {
1222 }
1227 }
1229 }
1231 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
1232 simplification is possible.
1233 If negate_expr_p would return true for T, NULL_TREE will never be
1234 returned. */
1236 static tree
1238 {
1240 tree tem;
1243 {
1244 /* Convert - (~A) to A + 1. */
1260 /* Two's complement FP formats, such as c4x, may overflow. */
1270 {
1279 }
1301 {
1302 /* -(A + B) -> (-B) - A. */
1306 {
1310 }
1312 /* -(A + B) -> (-A) - B. */
1314 {
1318 }
1319 }
1323 /* - (A - B) -> B - A */
1335 /* Fall through. */
1339 {
1348 }
1356 /* In general we can't negate A / B, because if A is INT_MIN and
1357 B is 1, we may turn this into INT_MIN / -1 which is undefined
1358 and actually traps on some architectures. But if overflow is
1359 undefined, we can negate, because - (INT_MIN / 1) is an
1360 overflow. */
1362 {
1367 {
1374 }
1377 {
1384 }
1385 }
1389 /* Convert -((double)float) into (double)(-float). */
1391 {
1395 }
1399 /* Negate -f(x) as f(-x). */
1402 {
1408 }
1412 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1414 {
1419 {
1426 }
1427 }
1432 }
1435 }
1437 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
1438 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
1439 return NULL_TREE. */
1441 static tree
1443 {
1456 }
1457 \f
1458 /* Split a tree IN into a constant, literal and variable parts that could be
1459 combined with CODE to make IN. "constant" means an expression with
1460 TREE_CONSTANT but that isn't an actual constant. CODE must be a
1461 commutative arithmetic operation. Store the constant part into *CONP,
1462 the literal in *LITP and return the variable part. If a part isn't
1463 present, set it to null. If the tree does not decompose in this way,
1464 return the entire tree as the variable part and the other parts as null.
1466 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
1467 case, we negate an operand that was subtracted. Except if it is a
1468 literal for which we use *MINUS_LITP instead.
1470 If NEGATE_P is true, we are negating all of IN, again except a literal
1471 for which we use *MINUS_LITP instead.
1473 If IN is itself a literal or constant, return it as appropriate.
1475 Note that we do not guarantee that any of the three values will be the
1476 same type as IN, but they will have the same signedness and mode. */
1478 static tree
1481 {
1488 /* Strip any conversions that don't change the machine mode or signedness. */
1497 /* We can associate addition and subtraction together (even
1498 though the C standard doesn't say so) for integers because
1499 the value is not affected. For reals, the value might be
1500 affected, so we can't. */
1503 {
1509 /* First see if either of the operands is a literal, then a constant. */
1522 /* If we haven't dealt with either operand, this is not a case we can
1523 decompose. Otherwise, VAR is either of the ones remaining, if any. */
1528 else
1531 /* Now do any needed negations. */
1538 }
1541 else
1545 {
1552 }
1555 }
1557 /* Re-associate trees split by the above function. T1 and T2 are either
1558 expressions to associate or null. Return the new expression, if any. If
1559 we build an operation, do it in TYPE and with CODE. */
1561 static tree
1563 {
1569 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
1570 try to fold this since we will have infinite recursion. But do
1571 deal with any NEGATE_EXPRs. */
1574 {
1576 {
1585 }
1587 {
1590 }
1594 }
1598 }
1599 \f
1600 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1601 for use in int_const_binop, size_binop and size_diffop. */
1603 static bool
1605 {
1612 {
1621 }
1626 }
1629 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1630 to produce a new constant. Return NULL_TREE if we don't know how
1631 to evaluate CODE at compile-time.
1633 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1635 tree
1637 {
1641 HOST_WIDE_INT hi;
1643 HOST_WIDE_INT garbageh;
1644 tree t;
1647 int is_sizetype
1657 {
1673 /* It's unclear from the C standard whether shifts can overflow.
1674 The following code ignores overflow; perhaps a C standard
1675 interpretation ruling is needed. */
1704 /* This is a shortcut for a common special case. */
1709 {
1715 }
1717 /* ... fall through ... */
1723 {
1726 }
1729 {
1732 }
1739 /* This is a shortcut for a common special case. */
1744 {
1749 }
1751 /* ... fall through ... */
1769 else
1775 else
1781 }
1784 {
1787 /* Propagate overflow flags ourselves. */
1790 {
1793 }
1794 }
1795 else
1801 }
1803 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1804 constant. We assume ARG1 and ARG2 have the same data type, or at least
1805 are the same kind of constant and the same machine mode. Return zero if
1806 combining the constants is not allowed in the current operating mode.
1808 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1810 static tree
1812 {
1813 /* Sanity check for the recursive cases. */
1824 {
1826 REAL_VALUE_TYPE d1;
1827 REAL_VALUE_TYPE d2;
1828 REAL_VALUE_TYPE value;
1829 REAL_VALUE_TYPE result;
1833 /* The following codes are handled by real_arithmetic. */
1835 {
1846 }
1854 /* Don't perform operation if we honor signaling NaNs and
1855 either operand is a NaN. */
1860 /* Don't perform operation if it would raise a division
1861 by zero exception. */
1867 /* If either operand is a NaN, just return it. Otherwise, set up
1868 for floating-point trap; we return an overflow. */
1877 /* Don't constant fold this floating point operation if
1878 the result has overflowed and flag_trapping_math. */
1886 /* Don't constant fold this floating point operation if the
1887 result may dependent upon the run-time rounding mode and
1888 flag_rounding_math is set, or if GCC's software emulation
1889 is unable to accurately represent the result. */
1900 }
1903 {
1904 FIXED_VALUE_TYPE f1;
1905 FIXED_VALUE_TYPE f2;
1906 FIXED_VALUE_TYPE result;
1911 /* The following codes are handled by fixed_arithmetic. */
1913 {
1930 }
1937 /* Propagate overflow flags. */
1939 {
1942 }
1946 }
1949 {
1958 {
1969 notrunc);
1973 notrunc);
1977 {
1978 tree magsquared
1982 notrunc);
1983 tree t1
1987 notrunc);
1988 tree t2
1992 notrunc);
1999 }
2004 }
2008 }
2011 }
2013 /* Create a size type INT_CST node with NUMBER sign extended. KIND
2014 indicates which particular sizetype to create. */
2016 tree
2018 {
2020 }
2021 \f
2022 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2023 is a tree code. The type of the result is taken from the operands.
2024 Both must be equivalent integer types, ala int_binop_types_match_p.
2025 If the operands are constant, so is the result. */
2027 tree
2029 {
2038 /* Handle the special case of two integer constants faster. */
2040 {
2041 /* And some specific cases even faster than that. */
2043 {
2048 }
2050 {
2053 }
2055 {
2058 }
2060 /* Handle general case of two integer constants. */
2062 }
2065 }
2067 /* Given two values, either both of sizetype or both of bitsizetype,
2068 compute the difference between the two values. Return the value
2069 in signed type corresponding to the type of the operands. */
2071 tree
2073 {
2075 tree ctype;
2080 /* If the type is already signed, just do the simple thing. */
2088 else
2091 /* If either operand is not a constant, do the conversions to the signed
2092 type and subtract. The hardware will do the right thing with any
2093 overflow in the subtraction. */
2098 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2099 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2100 overflow) and negate (which can't either). Special-case a result
2101 of zero while we're here. */
2106 else
2110 }
2111 \f
2112 /* A subroutine of fold_convert_const handling conversions of an
2113 INTEGER_CST to another integer type. */
2115 static tree
2117 {
2118 tree t;
2120 /* Given an integer constant, make new constant with new type,
2121 appropriately sign-extended or truncated. */
2124 /* Don't set the overflow when
2125 converting from a pointer, */
2127 /* or to a sizetype with same signedness
2128 and the precision is unchanged.
2129 ??? sizetype is always sign-extended,
2130 but its signedness depends on the
2131 frontend. Thus we see spurious overflows
2132 here if we do not check this. */
2147 }
2149 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2150 to an integer type. */
2152 static tree
2154 {
2156 tree t;
2158 /* The following code implements the floating point to integer
2159 conversion rules required by the Java Language Specification,
2160 that IEEE NaNs are mapped to zero and values that overflow
2161 the target precision saturate, i.e. values greater than
2162 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2163 are mapped to INT_MIN. These semantics are allowed by the
2164 C and C++ standards that simply state that the behavior of
2165 FP-to-integer conversion is unspecified upon overflow. */
2168 REAL_VALUE_TYPE r;
2172 {
2179 }
2181 /* If R is NaN, return zero and show we have an overflow. */
2183 {
2187 }
2189 /* See if R is less than the lower bound or greater than the
2190 upper bound. */
2193 {
2197 {
2201 }
2202 }
2205 {
2208 {
2211 {
2215 }
2216 }
2217 }
2225 }
2227 /* A subroutine of fold_convert_const handling conversions of a
2228 FIXED_CST to an integer type. */
2230 static tree
2232 {
2233 tree t;
2237 /* Right shift FIXED_CST to temp by fbit. */
2241 {
2246 /* Left shift temp to temp_trunc by fbit. */
2251 }
2252 else
2253 {
2258 }
2260 /* If FIXED_CST is negative, we need to round the value toward 0.
2261 By checking if the fractional bits are not zero to add 1 to temp. */
2264 {
2265 double_int one;
2269 }
2271 /* Given a fixed-point constant, make new constant with new type,
2272 appropriately sign-extended or truncated. */
2280 }
2282 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2283 to another floating point type. */
2285 static tree
2287 {
2288 REAL_VALUE_TYPE value;
2289 tree t;
2296 }
2298 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2299 to a floating point type. */
2301 static tree
2303 {
2304 REAL_VALUE_TYPE value;
2305 tree t;
2314 }
2316 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2317 to another fixed-point type. */
2319 static tree
2321 {
2322 FIXED_VALUE_TYPE value;
2323 tree t;
2330 /* Propagate overflow flags. */
2332 {
2335 }
2339 }
2341 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2342 to a fixed-point type. */
2344 static tree
2346 {
2347 FIXED_VALUE_TYPE value;
2348 tree t;
2357 /* Propagate overflow flags. */
2359 {
2362 }
2366 }
2368 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2369 to a fixed-point type. */
2371 static tree
2373 {
2374 FIXED_VALUE_TYPE value;
2375 tree t;
2383 /* Propagate overflow flags. */
2385 {
2388 }
2392 }
2394 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2395 type TYPE. If no simplification can be done return NULL_TREE. */
2397 static tree
2399 {
2404 {
2411 }
2413 {
2420 }
2422 {
2429 }
2431 }
2433 /* Construct a vector of zero elements of vector type TYPE. */
2435 static tree
2437 {
2448 }
2450 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2452 bool
2454 {
2469 {
2481 }
2482 }
2484 /* Convert expression ARG to type TYPE. Used by the middle-end for
2485 simple conversions in preference to calling the front-end's convert. */
2487 tree
2489 {
2491 tree tem;
2505 {
2510 {
2514 }
2519 {
2522 }
2529 {
2533 }
2535 {
2539 }
2541 {
2545 }
2548 {
2566 }
2571 {
2575 }
2578 {
2592 }
2596 {
2606 {
2610 {
2614 }
2622 }
2626 }
2644 }
2645 }
2646 \f
2647 /* Return false if expr can be assumed not to be an lvalue, true
2648 otherwise. */
2650 static bool
2652 {
2653 /* We only need to wrap lvalue tree codes. */
2655 {
2690 /* Assume the worst for front-end tree codes. */
2694 }
2697 }
2699 /* Return an expr equal to X but certainly not valid as an lvalue. */
2701 tree
2703 {
2704 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2705 us. */
2712 }
2714 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2715 Zero means allow extended lvalues. */
2719 /* When pedantic, return an expr equal to X but certainly not valid as a
2720 pedantic lvalue. Otherwise, return X. */
2722 static tree
2724 {
2727 else
2729 }
2730 \f
2731 /* Given a tree comparison code, return the code that is the logical inverse
2732 of the given code. It is not safe to do this for floating-point
2733 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2734 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2736 enum tree_code
2738 {
2743 {
2774 }
2775 }
2777 /* Similar, but return the comparison that results if the operands are
2778 swapped. This is safe for floating-point. */
2780 enum tree_code
2782 {
2784 {
2810 }
2811 }
2814 /* Convert a comparison tree code from an enum tree_code representation
2815 into a compcode bit-based encoding. This function is the inverse of
2816 compcode_to_comparison. */
2818 static enum comparison_code
2820 {
2822 {
2853 }
2854 }
2856 /* Convert a compcode bit-based encoding of a comparison operator back
2857 to GCC's enum tree_code representation. This function is the
2858 inverse of comparison_to_compcode. */
2860 static enum tree_code
2862 {
2864 {
2895 }
2896 }
2898 /* Return a tree for the comparison which is the combination of
2899 doing the AND or OR (depending on CODE) of the two operations LCODE
2900 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2901 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2902 if this makes the transformation invalid. */
2904 tree
2908 {
2915 {
2926 }
2929 {
2930 /* Eliminate unordered comparisons, as well as LTGT and ORD
2931 which are not used unless the mode has NaNs. */
2937 }
2939 {
2940 /* Check that the original operation and the optimized ones will trap
2941 under the same condition. */
2952 /* In a short-circuited boolean expression the LHS might be
2953 such that the RHS, if evaluated, will never trap. For
2954 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2955 if neither x nor y is NaN. (This is a mixed blessing: for
2956 example, the expression above will never trap, hence
2957 optimizing it to x < y would be invalid). */
2962 /* If the comparison was short-circuited, and only the RHS
2963 trapped, we may now generate a spurious trap. */
2968 /* If we changed the conditions that cause a trap, we lose. */
2971 }
2977 else
2980 }
2982 /* Return nonzero if CODE is a tree code that represents a truth value. */
2984 static int
2986 {
2991 }
2992 \f
2993 /* Return nonzero if two operands (typically of the same tree node)
2994 are necessarily equal. If either argument has side-effects this
2995 function returns zero. FLAGS modifies behavior as follows:
2997 If OEP_ONLY_CONST is set, only return nonzero for constants.
2998 This function tests whether the operands are indistinguishable;
2999 it does not test whether they are equal using C's == operation.
3000 The distinction is important for IEEE floating point, because
3001 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3002 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3004 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3005 even though it may hold multiple values during a function.
3006 This is because a GCC tree node guarantees that nothing else is
3007 executed between the evaluation of its "operands" (which may often
3008 be evaluated in arbitrary order). Hence if the operands themselves
3009 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3010 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3011 unset means assuming isochronic (or instantaneous) tree equivalence.
3012 Unless comparing arbitrary expression trees, such as from different
3013 statements, this flag can usually be left unset.
3015 If OEP_PURE_SAME is set, then pure functions with identical arguments
3016 are considered the same. It is used when the caller has other ways
3017 to ensure that global memory is unchanged in between. */
3019 int
3021 {
3022 /* If either is ERROR_MARK, they aren't equal. */
3026 /* If both types don't have the same signedness, then we can't consider
3027 them equal. We must check this before the STRIP_NOPS calls
3028 because they may change the signedness of the arguments. */
3032 /* If both types don't have the same precision, then it is not safe
3033 to strip NOPs. */
3040 /* In case both args are comparisons but with different comparison
3041 code, try to swap the comparison operands of one arg to produce
3042 a match and compare that variant. */
3046 {
3054 }
3057 /* This is needed for conversions and for COMPONENT_REF.
3058 Might as well play it safe and always test this. */
3064 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3065 We don't care about side effects in that case because the SAVE_EXPR
3066 takes care of that for us. In all other cases, two expressions are
3067 equal if they have no side effects. If we have two identical
3068 expressions with side effects that should be treated the same due
3069 to the only side effects being identical SAVE_EXPR's, that will
3070 be detected in the recursive calls below. */
3076 /* Next handle constant cases, those for which we can return 1 even
3077 if ONLY_CONST is set. */
3080 {
3095 {
3096 /* If we do not distinguish between signed and unsigned zero,
3097 consider them equal. */
3100 }
3104 {
3110 {
3112 flags))
3116 }
3119 }
3123 flags)
3125 flags));
3138 }
3143 /* Define macros to test an operand from arg0 and arg1 for equality and a
3144 variant that allows null and views null as being different from any
3145 non-null value. In the latter case, if either is null, the both
3146 must be; otherwise, do the normal comparison. */
3147 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3148 TREE_OPERAND (arg1, N), flags)
3150 #define OP_SAME_WITH_NULL(N) \
3151 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3152 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3155 {
3157 /* Two conversions are equal only if signedness and modes match. */
3159 {
3169 }
3179 /* For commutative ops, allow the other order. */
3187 /* If either of the pointer (or reference) expressions we are
3188 dereferencing contain a side effect, these cannot be equal. */
3194 {
3204 /* Operands 2 and 3 may be null.
3205 Compare the array index by value if it is constant first as we
3206 may have different types but same value here. */
3215 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3216 may be NULL when we're called to compare MEM_EXPRs. */
3226 }
3230 {
3245 /* Otherwise take into account this is a commutative operation. */
3253 }
3257 {
3259 /* If the CALL_EXPRs call different functions, then they
3260 clearly can not be equal. */
3262 flags))
3265 {
3269 else
3273 }
3275 /* Now see if all the arguments are the same. */
3276 {
3287 /* If we get here and both argument lists are exhausted
3288 then the CALL_EXPRs are equal. */
3290 }
3293 }
3296 /* Consider __builtin_sqrt equal to sqrt. */
3304 }
3306 #undef OP_SAME
3307 #undef OP_SAME_WITH_NULL
3308 }
3309 \f
3310 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3311 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3313 When in doubt, return 0. */
3315 static int
3317 {
3329 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3330 and see if the inner values are the same. This removes any
3331 signedness comparison, which doesn't matter here. */
3338 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3339 actual comparison operand, ARG0.
3341 First throw away any conversions to wider types
3342 already present in the operands. */
3351 {
3354 /* Make sure shorter operand is extended the right way
3355 to match the longer operand. */
3361 }
3364 }
3365 \f
3366 /* See if ARG is an expression that is either a comparison or is performing
3367 arithmetic on comparisons. The comparisons must only be comparing
3368 two different values, which will be stored in *CVAL1 and *CVAL2; if
3369 they are nonzero it means that some operands have already been found.
3370 No variables may be used anywhere else in the expression except in the
3371 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3372 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3374 If this is true, return 1. Otherwise, return zero. */
3376 static int
3378 {
3382 /* We can handle some of the tcc_expression cases here. */
3392 {
3393 /* If we've already found a CVAL1 or CVAL2, this expression is
3394 two complex to handle. */
3400 }
3403 {
3426 /* First see if we can handle the first operand, then the second. For
3427 the second operand, we know *CVAL1 can't be zero. It must be that
3428 one side of the comparison is each of the values; test for the
3429 case where this isn't true by failing if the two operands
3430 are the same. */
3439 ;
3443 ;
3444 else
3448 ;
3452 ;
3453 else
3460 }
3461 }
3462 \f
3463 /* ARG is a tree that is known to contain just arithmetic operations and
3464 comparisons. Evaluate the operations in the tree substituting NEW0 for
3465 any occurrence of OLD0 as an operand of a comparison and likewise for
3466 NEW1 and OLD1. */
3468 static tree
3470 {
3475 /* We can handle some of the tcc_expression cases here. */
3483 {
3498 {
3515 }
3516 /* Fall through - ??? */
3519 {
3523 /* We need to check both for exact equality and tree equality. The
3524 former will be true if the operand has a side-effect. In that
3525 case, we know the operand occurred exactly once. */
3538 }
3542 }
3543 }
3544 \f
3545 /* Return a tree for the case when the result of an expression is RESULT
3546 converted to TYPE and OMITTED was previously an operand of the expression
3547 but is now not needed (e.g., we folded OMITTED * 0).
3549 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3550 the conversion of RESULT to TYPE. */
3552 tree
3554 {
3557 /* If the resulting operand is an empty statement, just return the omitted
3558 statement casted to void. */
3566 }
3568 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3570 static tree
3572 {
3575 /* If the resulting operand is an empty statement, just return the omitted
3576 statement casted to void. */
3584 }
3586 /* Return a tree for the case when the result of an expression is RESULT
3587 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3588 of the expression but are now not needed.
3590 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3591 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3592 evaluated before OMITTED2. Otherwise, if neither has side effects,
3593 just do the conversion of RESULT to TYPE. */
3595 tree
3597 {
3606 }
3608 \f
3609 /* Return a simplified tree node for the truth-negation of ARG. This
3610 never alters ARG itself. We assume that ARG is an operation that
3611 returns a truth value (0 or 1).
3613 FIXME: one would think we would fold the result, but it causes
3614 problems with the dominator optimizer. */
3616 tree
3618 {
3622 /* If this is a comparison, we can simply invert it, except for
3623 floating-point non-equality comparisons, in which case we just
3624 enclose a TRUTH_NOT_EXPR around what we have. */
3627 {
3630 && flag_trapping_math
3634 else
3635 {
3640 else
3643 }
3644 }
3647 {
3662 /* Here we can invert either operand. We invert the first operand
3663 unless the second operand is a TRUTH_NOT_EXPR in which case our
3664 result is the XOR of the first operand with the inside of the
3665 negation of the second operand. */
3670 else
3689 {
3692 /* A COND_EXPR may have a throw as one operand, which
3693 then has void type. Just leave void operands
3694 as they are. */
3700 }
3733 }
3736 }
3738 /* Return a simplified tree node for the truth-negation of ARG. This
3739 never alters ARG itself. We assume that ARG is an operation that
3740 returns a truth value (0 or 1).
3742 FIXME: one would think we would fold the result, but it causes
3743 problems with the dominator optimizer. */
3745 tree
3747 {
3748 tree tem;
3758 }
3760 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3761 operands are another bit-wise operation with a common input. If so,
3762 distribute the bit operations to save an operation and possibly two if
3763 constants are involved. For example, convert
3764 (A | B) & (A | C) into A | (B & C)
3765 Further simplification will occur if B and C are constants.
3767 If this optimization cannot be done, 0 will be returned. */
3769 static tree
3771 {
3772 tree common;
3782 {
3786 }
3788 {
3792 }
3794 {
3798 }
3800 {
3804 }
3805 else
3810 }
3812 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3813 with code CODE. This optimization is unsafe. */
3814 static tree
3816 {
3820 /* (A / C) +- (B / C) -> (A +- B) / C. */
3830 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3835 {
3847 }
3850 }
3851 \f
3852 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3853 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3855 static tree
3858 {
3859 tree result;
3862 {
3869 }
3877 }
3879 /* Optimize a bit-field compare.
3881 There are two cases: First is a compare against a constant and the
3882 second is a comparison of two items where the fields are at the same
3883 bit position relative to the start of a chunk (byte, halfword, word)
3884 large enough to contain it. In these cases we can avoid the shift
3885 implicit in bitfield extractions.
3887 For constants, we emit a compare of the shifted constant with the
3888 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3889 compared. For two fields at the same position, we do the ANDs with the
3890 similar mask and compare the result of the ANDs.
3892 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3893 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3894 are the left and right operands of the comparison, respectively.
3896 If the optimization described above can be done, we return the resulting
3897 tree. Otherwise we return zero. */
3899 static tree
3902 {
3911 tree mask;
3912 tree offset;
3914 /* Get all the information about the extractions being done. If the bit size
3915 if the same as the size of the underlying object, we aren't doing an
3916 extraction at all and so can do nothing. We also don't want to
3917 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3918 then will no longer be able to replace it. */
3926 {
3927 /* If this is not a constant, we can only do something if bit positions,
3928 sizes, and signedness are the same. */
3936 }
3938 /* See if we can find a mode to refer to this field. We should be able to,
3939 but fail if we can't. */
3948 /* Set signed and unsigned types of the precision of this mode for the
3949 shifts below. */
3953 /* Compute the bit position and size for the new reference and our offset
3954 within it. If the new reference is the same size as the original, we
3955 won't optimize anything, so return zero. */
3965 /* Make the mask to be used against the extracted field. */
3972 /* If not comparing with constant, just rework the comparison
3973 and return. */
3977 unsigned_type,
3980 mask),
3983 unsigned_type,
3986 mask));
3988 /* Otherwise, we are handling the constant case. See if the constant is too
3989 big for the field. Warn and return a tree of for 0 (false) if so. We do
3990 this not only for its own sake, but to avoid having to test for this
3991 error case below. If we didn't, we might generate wrong code.
3993 For unsigned fields, the constant shifted right by the field length should
3994 be all zero. For signed fields, the high-order bits should agree with
3995 the sign bit. */
3998 {
4002 {
4006 }
4007 }
4008 else
4009 {
4013 {
4017 }
4018 }
4020 /* Single-bit compares should always be against zero. */
4022 {
4025 }
4027 /* Make a new bitfield reference, shift the constant over the
4028 appropriate number of bits and mask it with the computed mask
4029 (in case this was a signed field). If we changed it, make a new one. */
4032 {
4035 }
4045 rhs);
4046 }
4047 \f
4048 /* Subroutine for fold_truthop: decode a field reference.
4050 If EXP is a comparison reference, we return the innermost reference.
4052 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4053 set to the starting bit number.
4055 If the innermost field can be completely contained in a mode-sized
4056 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4058 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4059 otherwise it is not changed.
4061 *PUNSIGNEDP is set to the signedness of the field.
4063 *PMASK is set to the mask used. This is either contained in a
4064 BIT_AND_EXPR or derived from the width of the field.
4066 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4068 Return 0 if this is not a component reference or is one that we can't
4069 do anything with. */
4071 static tree
4076 {
4080 tree unsigned_type;
4083 /* All the optimizations using this function assume integer fields.
4084 There are problems with FP fields since the type_for_size call
4085 below can fail for, e.g., XFmode. */
4089 /* We are interested in the bare arrangement of bits, so strip everything
4090 that doesn't affect the machine mode. However, record the type of the
4091 outermost expression if it may matter below. */
4099 {
4105 }
4114 /* If the number of bits in the reference is the same as the bitsize of
4115 the outer type, then the outer type gives the signedness. Otherwise
4116 (in case of a small bitfield) the signedness is unchanged. */
4120 /* Compute the mask to access the bitfield. */
4129 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4137 }
4139 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4140 bit positions. */
4142 static int
4144 {
4147 tree tmask;
4151 return
4158 }
4160 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4161 represents the sign bit of EXP's type. If EXP represents a sign
4162 or zero extension, also test VAL against the unextended type.
4163 The return value is the (sub)expression whose sign bit is VAL,
4164 or NULL_TREE otherwise. */
4166 static tree
4168 {
4172 tree t;
4174 /* Tree EXP must have an integral type. */
4179 /* Tree VAL must be an integer constant. */
4186 {
4193 }
4194 else
4195 {
4202 }
4204 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
4205 treat VAL as if it were unsigned. */
4210 /* Handle extension from a narrower type. */
4216 }
4218 /* Subroutine for fold_truthop: determine if an operand is simple enough
4219 to be evaluated unconditionally. */
4221 static int
4223 {
4224 /* Strip any conversions that don't change the machine mode. */
4233 /* Don't regard global variables as simple. They may be
4234 allocated in ways unknown to the compiler (shared memory,
4235 #pragma weak, etc). */
4238 /* Loading a static variable is unduly expensive, but global
4239 registers aren't expensive. */
4241 }
4242 \f
4243 /* The following functions are subroutines to fold_range_test and allow it to
4244 try to change a logical combination of comparisons into a range test.
4246 For example, both
4247 X == 2 || X == 3 || X == 4 || X == 5
4248 and
4249 X >= 2 && X <= 5
4250 are converted to
4251 (unsigned) (X - 2) <= 3
4253 We describe each set of comparisons as being either inside or outside
4254 a range, using a variable named like IN_P, and then describe the
4255 range with a lower and upper bound. If one of the bounds is omitted,
4256 it represents either the highest or lowest value of the type.
4258 In the comments below, we represent a range by two numbers in brackets
4259 preceded by a "+" to designate being inside that range, or a "-" to
4260 designate being outside that range, so the condition can be inverted by
4261 flipping the prefix. An omitted bound is represented by a "-". For
4262 example, "- [-, 10]" means being outside the range starting at the lowest
4263 possible value and ending at 10, in other words, being greater than 10.
4264 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4265 always false.
4267 We set up things so that the missing bounds are handled in a consistent
4268 manner so neither a missing bound nor "true" and "false" need to be
4269 handled using a special case. */
4271 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4272 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4273 and UPPER1_P are nonzero if the respective argument is an upper bound
4274 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4275 must be specified for a comparison. ARG1 will be converted to ARG0's
4276 type if both are specified. */
4278 static tree
4281 {
4282 tree tem;
4286 /* If neither arg represents infinity, do the normal operation.
4287 Else, if not a comparison, return infinity. Else handle the special
4288 comparison rules. Note that most of the cases below won't occur, but
4289 are handled for consistency. */
4292 {
4297 }
4302 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4303 for neither. In real maths, we cannot assume open ended ranges are
4304 the same. But, this is computer arithmetic, where numbers are finite.
4305 We can therefore make the transformation of any unbounded range with
4306 the value Z, Z being greater than any representable number. This permits
4307 us to treat unbounded ranges as equal. */
4311 {
4332 }
4335 }
4336 \f
4337 /* Given EXP, a logical expression, set the range it is testing into
4338 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4339 actually being tested. *PLOW and *PHIGH will be made of the same
4340 type as the returned expression. If EXP is not a comparison, we
4341 will most likely not be returning a useful value and range. Set
4342 *STRICT_OVERFLOW_P to true if the return value is only valid
4343 because signed overflow is undefined; otherwise, do not change
4344 *STRICT_OVERFLOW_P. */
4346 static tree
4349 {
4356 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4357 and see if we can refine the range. Some of the cases below may not
4358 happen, but it doesn't seem worth worrying about this. We "continue"
4359 the outer loop when we've changed something; otherwise we "break"
4360 the switch, which will "break" the while. */
4366 {
4371 {
4383 }
4386 {
4393 /* We can only do something if the range is testing for zero
4394 and if the second operand is an integer constant. Note that
4395 saying something is "in" the range we make is done by
4396 complementing IN_P since it will set in the initial case of
4397 being not equal to zero; "out" is leaving it alone. */
4404 {
4425 }
4427 /* If this is an unsigned comparison, we also know that EXP is
4428 greater than or equal to zero. We base the range tests we make
4429 on that fact, so we record it here so we can parse existing
4430 range tests. We test arg0_type since often the return type
4431 of, e.g. EQ_EXPR, is boolean. */
4433 {
4437 NULL_TREE))
4442 /* If the high bound is missing, but we have a nonzero low
4443 bound, reverse the range so it goes from zero to the low bound
4444 minus 1. */
4446 {
4451 }
4452 }
4458 /* (-x) IN [a,b] -> x in [-b, -a] */
4470 /* ~ X -> -X - 1 */
4479 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4480 move a constant to the other side. */
4485 /* If EXP is signed, any overflow in the computation is undefined,
4486 so we don't worry about it so long as our computations on
4487 the bounds don't overflow. For unsigned, overflow is defined
4488 and this is exactly the right thing. */
4500 /* Check for an unsigned range which has wrapped around the maximum
4501 value thus making n_high < n_low, and normalize it. */
4503 {
4509 /* If the range is of the form +/- [ x+1, x ], we won't
4510 be able to normalize it. But then, it represents the
4511 whole range or the empty set, so make it
4512 +/- [ -, - ]. */
4516 else
4518 }
4519 else
4543 /* If we're converting arg0 from an unsigned type, to exp,
4544 a signed type, we will be doing the comparison as unsigned.
4545 The tests above have already verified that LOW and HIGH
4546 are both positive.
4548 So we have to ensure that we will handle large unsigned
4549 values the same way that the current signed bounds treat
4550 negative values. */
4553 {
4554 tree high_positive;
4555 tree equiv_type;
4556 /* For fixed-point modes, we need to pass the saturating flag
4557 as the 2nd parameter. */
4562 else
4566 /* A range without an upper bound is, naturally, unbounded.
4567 Since convert would have cropped a very large value, use
4568 the max value for the destination type. */
4569 high_positive
4576 high_positive),
4579 /* If the low bound is specified, "and" the range with the
4580 range for which the original unsigned value will be
4581 positive. */
4583 {
4587 integer_zero_node),
4588 high_positive))
4592 }
4593 else
4594 {
4595 /* Otherwise, "or" the range with the range of the input
4596 that will be interpreted as negative. */
4600 integer_zero_node),
4601 high_positive))
4605 }
4606 }
4614 }
4617 }
4619 /* If EXP is a constant, we can evaluate whether this is true or false. */
4621 {
4628 }
4632 }
4633 \f
4634 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4635 type, TYPE, return an expression to test if EXP is in (or out of, depending
4636 on IN_P) the range. Return 0 if the test couldn't be created. */
4638 static tree
4640 {
4642 tree value;
4644 #ifdef HAVE_canonicalize_funcptr_for_compare
4645 /* Disable this optimization for function pointer expressions
4646 on targets that require function pointer canonicalization. */
4651 #endif
4654 {
4660 }
4678 {
4680 {
4684 }
4686 }
4688 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4690 {
4692 HOST_WIDE_INT hi;
4697 {
4700 }
4701 else
4702 {
4705 }
4708 {
4710 {
4713 }
4716 }
4717 }
4719 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4720 This requires wrap-around arithmetics for the type of the expression. */
4722 {
4724 /* There is no requirement that LOW be within the range of ETYPE
4725 if the latter is a subtype. It must, however, be within the base
4726 type of ETYPE. So be sure we do the subtraction in that type. */
4739 }
4741 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4744 {
4747 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4748 for the type in question, as we rely on this here. */
4758 else
4760 }
4770 {
4772 {
4778 }
4780 }
4788 }
4789 \f
4790 /* Return the predecessor of VAL in its type, handling the infinite case. */
4792 static tree
4794 {
4800 else
4802 }
4804 /* Return the successor of VAL in its type, handling the infinite case. */
4806 static tree
4808 {
4814 else
4816 }
4818 /* Given two ranges, see if we can merge them into one. Return 1 if we
4819 can, 0 if we can't. Set the output range into the specified parameters. */
4821 static int
4824 {
4828 tree tem;
4838 /* Make range 0 be the range that starts first, or ends last if they
4839 start at the same value. Swap them if it isn't. */
4842 || (lowequal
4845 {
4849 }
4851 /* Now flag two cases, whether the ranges are disjoint or whether the
4852 second range is totally subsumed in the first. Note that the tests
4853 below are simplified by the ones above. */
4859 /* We now have four cases, depending on whether we are including or
4860 excluding the two ranges. */
4862 {
4863 /* If they don't overlap, the result is false. If the second range
4864 is a subset it is the result. Otherwise, the range is from the start
4865 of the second to the end of the first. */
4870 else
4872 }
4875 {
4876 /* If they don't overlap, the result is the first range. If they are
4877 equal, the result is false. If the second range is a subset of the
4878 first, and the ranges begin at the same place, we go from just after
4879 the end of the second range to the end of the first. If the second
4880 range is not a subset of the first, or if it is a subset and both
4881 ranges end at the same place, the range starts at the start of the
4882 first range and ends just before the second range.
4883 Otherwise, we can't describe this as a single range. */
4889 {
4894 {
4895 /* We are in the weird situation where high0 > high1 but
4896 high1 has no successor. Punt. */
4898 }
4899 }
4901 {
4906 {
4907 /* low0 < low1 but low1 has no predecessor. Punt. */
4909 }
4910 }
4911 else
4913 }
4916 {
4917 /* If they don't overlap, the result is the second range. If the second
4918 is a subset of the first, the result is false. Otherwise,
4919 the range starts just after the first range and ends at the
4920 end of the second. */
4925 else
4926 {
4931 {
4932 /* high1 > high0 but high0 has no successor. Punt. */
4934 }
4935 }
4936 }
4938 else
4939 {
4940 /* The case where we are excluding both ranges. Here the complex case
4941 is if they don't overlap. In that case, the only time we have a
4942 range is if they are adjacent. If the second is a subset of the
4943 first, the result is the first. Otherwise, the range to exclude
4944 starts at the beginning of the first range and ends at the end of the
4945 second. */
4947 {
4952 else
4953 {
4954 /* Canonicalize - [min, x] into - [-, x]. */
4957 {
4962 /* FALLTHROUGH */
4975 }
4977 /* Canonicalize - [x, max] into - [x, -]. */
4980 {
4985 /* FALLTHROUGH */
5000 }
5002 /* The ranges might be also adjacent between the maximum and
5003 minimum values of the given type. For
5004 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5005 return + [x + 1, y - 1]. */
5007 {
5014 }
5015 else
5017 }
5018 }
5021 else
5023 }
5027 }
5028 \f
5030 /* Subroutine of fold, looking inside expressions of the form
5031 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5032 of the COND_EXPR. This function is being used also to optimize
5033 A op B ? C : A, by reversing the comparison first.
5035 Return a folded expression whose code is not a COND_EXPR
5036 anymore, or NULL_TREE if no folding opportunity is found. */
5038 static tree
5040 {
5045 tree tem;
5050 /* If we have A op 0 ? A : -A, consider applying the following
5051 transformations:
5053 A == 0? A : -A same as -A
5054 A != 0? A : -A same as A
5055 A >= 0? A : -A same as abs (A)
5056 A > 0? A : -A same as abs (A)
5057 A <= 0? A : -A same as -abs (A)
5058 A < 0? A : -A same as -abs (A)
5060 None of these transformations work for modes with signed
5061 zeros. If A is +/-0, the first two transformations will
5062 change the sign of the result (from +0 to -0, or vice
5063 versa). The last four will fix the sign of the result,
5064 even though the original expressions could be positive or
5065 negative, depending on the sign of A.
5067 Note that all these transformations are correct if A is
5068 NaN, since the two alternatives (A and -A) are also NaNs. */
5074 /* In the case that A is of the form X-Y, '-A' (arg2) may
5075 have already been folded to Y-X, check for that. */
5083 {
5095 /* Fall through. */
5117 }
5119 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5120 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5121 both transformations are correct when A is NaN: A != 0
5122 is then true, and A == 0 is false. */
5125 {
5130 }
5132 /* Try some transformations of A op B ? A : B.
5134 A == B? A : B same as B
5135 A != B? A : B same as A
5136 A >= B? A : B same as max (A, B)
5137 A > B? A : B same as max (B, A)
5138 A <= B? A : B same as min (A, B)
5139 A < B? A : B same as min (B, A)
5141 As above, these transformations don't work in the presence
5142 of signed zeros. For example, if A and B are zeros of
5143 opposite sign, the first two transformations will change
5144 the sign of the result. In the last four, the original
5145 expressions give different results for (A=+0, B=-0) and
5146 (A=-0, B=+0), but the transformed expressions do not.
5148 The first two transformations are correct if either A or B
5149 is a NaN. In the first transformation, the condition will
5150 be false, and B will indeed be chosen. In the case of the
5151 second transformation, the condition A != B will be true,
5152 and A will be chosen.
5154 The conversions to max() and min() are not correct if B is
5155 a number and A is not. The conditions in the original
5156 expressions will be false, so all four give B. The min()
5157 and max() versions would give a NaN instead. */
5159 /* Avoid these transformations if the COND_EXPR may be used
5160 as an lvalue in the C++ front-end. PR c++/19199. */
5161 && (in_gimple_form
5166 {
5171 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
5173 {
5177 }
5180 {
5189 /* In C++ a ?: expression can be an lvalue, so put the
5190 operand which will be used if they are equal first
5191 so that we can convert this back to the
5192 corresponding COND_EXPR. */
5194 {
5201 }
5208 {
5215 }
5228 }
5229 }
5231 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5232 we might still be able to simplify this. For example,
5233 if C1 is one less or one more than C2, this might have started
5234 out as a MIN or MAX and been transformed by this function.
5235 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5241 {
5243 /* We can replace A with C1 in this case. */
5248 /* If C1 is C2 + 1, this is min(A, C2). */
5250 OEP_ONLY_CONST)
5254 OEP_ONLY_CONST))
5256 type,
5258 arg2));
5262 /* If C1 is C2 - 1, this is min(A, C2). */
5264 OEP_ONLY_CONST)
5268 OEP_ONLY_CONST))
5270 type,
5272 arg2));
5276 /* If C1 is C2 - 1, this is max(A, C2). */
5278 OEP_ONLY_CONST)
5282 OEP_ONLY_CONST))
5284 type,
5286 arg2));
5290 /* If C1 is C2 + 1, this is max(A, C2). */
5292 OEP_ONLY_CONST)
5296 OEP_ONLY_CONST))
5298 type,
5300 arg2));
5306 }
5309 }
5312 \f
5313 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5314 #define LOGICAL_OP_NON_SHORT_CIRCUIT (BRANCH_COST >= 2)
5315 #endif
5317 /* EXP is some logical combination of boolean tests. See if we can
5318 merge it into some range test. Return the new tree if so. */
5320 static tree
5322 {
5330 tree tem;
5334 /* If this is an OR operation, invert both sides; we will invert
5335 again at the end. */
5339 /* If both expressions are the same, if we can merge the ranges, and we
5340 can build the range test, return it or it inverted. If one of the
5341 ranges is always true or always false, consider it to be the same
5342 expression as the other. */
5350 {
5354 }
5356 /* On machines where the branch cost is expensive, if this is a
5357 short-circuited branch and the underlying object on both sides
5358 is the same, make a non-short-circuit operation. */
5364 {
5365 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5366 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5367 which cases we can't do this. */
5375 {
5384 {
5387 WARN_STRICT_OVERFLOW_COMPARISON);
5391 }
5392 }
5393 }
5396 }
5397 \f
5398 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5399 bit value. Arrange things so the extra bits will be set to zero if and
5400 only if C is signed-extended to its full width. If MASK is nonzero,
5401 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5403 static tree
5405 {
5408 tree temp;
5413 /* We work by getting just the sign bit into the low-order bit, then
5414 into the high-order bit, then sign-extend. We then XOR that value
5415 with C. */
5419 /* We must use a signed type in order to get an arithmetic right shift.
5420 However, we must also avoid introducing accidental overflows, so that
5421 a subsequent call to integer_zerop will work. Hence we must
5422 do the type conversion here. At this point, the constant is either
5423 zero or one, and the conversion to a signed type can never overflow.
5424 We could get an overflow if this conversion is done anywhere else. */
5433 /* If necessary, convert the type back to match the type of C. */
5438 }
5439 \f
5440 /* Find ways of folding logical expressions of LHS and RHS:
5441 Try to merge two comparisons to the same innermost item.
5442 Look for range tests like "ch >= '0' && ch <= '9'".
5443 Look for combinations of simple terms on machines with expensive branches
5444 and evaluate the RHS unconditionally.
5446 For example, if we have p->a == 2 && p->b == 4 and we can make an
5447 object large enough to span both A and B, we can do this with a comparison
5448 against the object ANDed with the a mask.
5450 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5451 operations to do this with one comparison.
5453 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5454 function and the one above.
5456 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5457 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5459 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5460 two operands.
5462 We return the simplified tree or 0 if no optimization is possible. */
5464 static tree
5466 {
5467 /* If this is the "or" of two comparisons, we can do something if
5468 the comparisons are NE_EXPR. If this is the "and", we can do something
5469 if the comparisons are EQ_EXPR. I.e.,
5470 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5472 WANTED_CODE is this operation code. For single bit fields, we can
5473 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5474 comparison for one-bit fields. */
5496 /* Start by getting the comparison codes. Fail if anything is volatile.
5497 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5498 it were surrounded with a NE_EXPR. */
5507 {
5511 }
5514 {
5518 }
5529 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5532 {
5533 tree result;
5536 {
5541 }
5544 {
5550 }
5551 }
5556 /* If the RHS can be evaluated unconditionally and its operands are
5557 simple, it wins to evaluate the RHS unconditionally on machines
5558 with expensive branches. In this case, this isn't a comparison
5559 that can be merged. Avoid doing this if the RHS is a floating-point
5560 comparison since those can trap. */
5566 {
5567 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5577 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5588 {
5592 }
5593 }
5595 /* See if the comparisons can be merged. Then get all the parameters for
5596 each side. */
5620 /* It must be true that the inner operation on the lhs of each
5621 comparison must be the same if we are to be able to do anything.
5622 Then see if we have constants. If not, the same must be true for
5623 the rhs's. */
5634 else
5637 /* If either comparison code is not correct for our logical operation,
5638 fail. However, we can convert a one-bit comparison against zero into
5639 the opposite comparison against that bit being set in the field. */
5643 {
5645 {
5646 /* Make the left operand unsigned, since we are only interested
5647 in the value of one bit. Otherwise we are doing the wrong
5648 thing below. */
5651 }
5652 else
5654 }
5656 /* This is analogous to the code for l_const above. */
5658 {
5660 {
5663 }
5664 else
5666 }
5668 /* See if we can find a mode that contains both fields being compared on
5669 the left. If we can't, fail. Otherwise, update all constants and masks
5670 to be relative to a field of that size. */
5675 volatilep);
5685 {
5688 }
5696 {
5704 {
5708 }
5709 }
5711 {
5719 {
5723 }
5724 }
5726 /* If the right sides are not constant, do the same for it. Also,
5727 disallow this optimization if a size or signedness mismatch occurs
5728 between the left and right sides. */
5730 {
5733 /* Make sure the two fields on the right
5734 correspond to the left without being swapped. */
5742 volatilep);
5752 {
5755 }
5762 /* Make a mask that corresponds to both fields being compared.
5763 Do this for both items being compared. If the operands are the
5764 same size and the bits being compared are in the same position
5765 then we can do this by masking both and comparing the masked
5766 results. */
5770 {
5782 }
5784 /* There is still another way we can do something: If both pairs of
5785 fields being compared are adjacent, we may be able to make a wider
5786 field containing them both.
5788 Note that we still must mask the lhs/rhs expressions. Furthermore,
5789 the mask must be shifted to account for the shift done by
5790 make_bit_field_ref. */
5795 {
5796 tree type;
5808 /* Convert to the smaller type before masking out unwanted bits. */
5811 {
5813 {
5817 }
5819 {
5823 }
5824 }
5833 }
5836 }
5838 /* Handle the case of comparisons with constants. If there is something in
5839 common between the masks, those bits of the constants must be the same.
5840 If not, the condition is always false. Test for this to avoid generating
5841 incorrect code below. */
5846 {
5848 {
5851 }
5852 else
5853 {
5856 }
5857 }
5859 /* Construct the expression we will return. First get the component
5860 reference we will make. Unless the mask is all ones the width of
5861 that field, perform the mask operation. Then compare with the
5862 merged constant. */
5872 }
5873 \f
5874 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5875 constant. */
5877 static tree
5879 {
5883 tree minmax_const;
5885 tree inner;
5895 /* If something does not permit us to optimize, return the original tree. */
5903 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5904 and GT_EXPR, doing the rest with recursive calls using logical
5905 simplifications. */
5907 {
5909 {
5915 }
5918 return
5920 optimize_minmax_comparison
5922 optimize_minmax_comparison
5927 /* MAX (X, 0) == 0 -> X <= 0 */
5931 /* MAX (X, 0) == 5 -> X == 5 */
5935 /* MAX (X, 0) == -1 -> false */
5939 /* MIN (X, 0) == 0 -> X >= 0 */
5943 /* MIN (X, 0) == 5 -> false */
5946 else
5947 /* MIN (X, 0) == -1 -> X == -1 */
5952 /* MAX (X, 0) > 0 -> X > 0
5953 MAX (X, 0) > 5 -> X > 5 */
5957 /* MAX (X, 0) > -1 -> true */
5961 /* MIN (X, 0) > 0 -> false
5962 MIN (X, 0) > 5 -> false */
5965 else
5966 /* MIN (X, 0) > -1 -> X > -1 */
5971 }
5972 }
5973 \f
5974 /* T is an integer expression that is being multiplied, divided, or taken a
5975 modulus (CODE says which and what kind of divide or modulus) by a
5976 constant C. See if we can eliminate that operation by folding it with
5977 other operations already in T. WIDE_TYPE, if non-null, is a type that
5978 should be used for the computation if wider than our type.
5980 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5981 (X * 2) + (Y * 4). We must, however, be assured that either the original
5982 expression would not overflow or that overflow is undefined for the type
5983 in the language in question.
5985 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5986 the machine has a multiply-accumulate insn or that this is part of an
5987 addressing calculation.
5989 If we return a non-null expression, it is an equivalent form of the
5990 original computation, but need not be in the original type.
5992 We set *STRICT_OVERFLOW_P to true if the return values depends on
5993 signed overflow being undefined. Otherwise we do not change
5994 *STRICT_OVERFLOW_P. */
5996 static tree
5999 {
6000 /* To avoid exponential search depth, refuse to allow recursion past
6001 three levels. Beyond that (1) it's highly unlikely that we'll find
6002 something interesting and (2) we've probably processed it before
6003 when we built the inner expression. */
6006 tree ret;
6011 depth++;
6013 depth--;
6016 }
6018 static tree
6021 {
6032 /* Don't deal with constants of zero here; they confuse the code below. */
6042 /* Note that we need not handle conditional operations here since fold
6043 already handles those cases. So just do arithmetic here. */
6045 {
6047 /* For a constant, we can always simplify if we are a multiply
6048 or (for divide and modulus) if it is a multiple of our constant. */
6056 /* If op0 is an expression ... */
6062 /* ... and is unsigned, and its type is smaller than ctype,
6063 then we cannot pass through as widening. */
6069 /* ... or this is a truncation (t is narrower than op0),
6070 then we cannot pass through this narrowing. */
6073 /* ... or signedness changes for division or modulus,
6074 then we cannot pass through this conversion. */
6078 /* ... or has undefined overflow while the converted to
6079 type has not, we cannot do the operation in the inner type
6080 as that would introduce undefined overflow. */
6085 /* Pass the constant down and see if we can make a simplification. If
6086 we can, replace this expression with the inner simplification for
6087 possible later conversion to our or some other type. */
6092 code == MULT_EXPR
6094 strict_overflow_p))))
6099 /* If widening the type changes it from signed to unsigned, then we
6100 must avoid building ABS_EXPR itself as unsigned. */
6102 {
6106 {
6109 }
6111 }
6112 /* If the constant is negative, we cannot simplify this. */
6115 /* FALLTHROUGH */
6123 /* If widening the type changes the signedness, then we can't perform
6124 this optimization as that changes the result. */
6128 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6134 {
6141 }
6145 /* If the second operand is constant, this is a multiplication
6146 or floor division, by a power of two, so we can treat it that
6147 way unless the multiplier or divisor overflows. Signed
6148 left-shift overflow is implementation-defined rather than
6149 undefined in C90, so do not convert signed left shift into
6150 multiplication. */
6153 /* const_binop may not detect overflow correctly,
6154 so check for it explicitly here. */
6159 size_one_node,
6169 /* See if we can eliminate the operation on both sides. If we can, we
6170 can return a new PLUS or MINUS. If we can't, the only remaining
6171 cases where we can do anything are if the second operand is a
6172 constant. */
6178 /* If not multiplication, we can only do this if both operands
6179 are divisible by c. */
6182 {
6187 }
6189 /* If this was a subtraction, negate OP1 and set it to be an addition.
6190 This simplifies the logic below. */
6197 /* If either OP1 or C are negative, this optimization is not safe for
6198 some of the division and remainder types while for others we need
6199 to change the code. */
6201 {
6209 }
6211 /* If it's a multiply or a division/modulus operation of a multiple
6212 of our constant, do the operation and verify it doesn't overflow. */
6215 {
6218 /* We allow the constant to overflow with wrapping semantics. */
6222 }
6223 else
6226 /* If we have an unsigned type is not a sizetype, we cannot widen
6227 the operation since it will change the result if the original
6228 computation overflowed. */
6234 /* If we were able to eliminate our operation from the first side,
6235 apply our operation to the second side and reform the PLUS. */
6239 /* The last case is if we are a multiply. In that case, we can
6240 apply the distributive law to commute the multiply and addition
6241 if the multiplication of the constants doesn't overflow. */
6247 op1);
6252 /* We have a special case here if we are doing something like
6253 (C * 8) % 4 since we know that's zero. */
6260 /* ... fall through ... */
6264 /* If we can extract our operation from the LHS, do so and return a
6265 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6266 do something only if the second operand is a constant. */
6280 /* If these are the same operation types, we can associate them
6281 assuming no overflow. */
6288 /* If these operations "cancel" each other, we have the main
6289 optimizations of this pass, which occur when either constant is a
6290 multiple of the other, in which case we replace this with either an
6291 operation or CODE or TCODE.
6293 If we have an unsigned type that is not a sizetype, we cannot do
6294 this since it will change the result if the original computation
6295 overflowed. */
6303 {
6305 {
6312 }
6314 {
6321 }
6322 }
6327 }
6330 }
6331 \f
6332 /* Return a node which has the indicated constant VALUE (either 0 or
6333 1), and is of the indicated TYPE. */
6335 tree
6337 {
6342 else
6344 }
6347 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6348 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6349 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6350 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6351 COND is the first argument to CODE; otherwise (as in the example
6352 given here), it is the second argument. TYPE is the type of the
6353 original expression. Return NULL_TREE if no simplification is
6354 possible. */
6356 static tree
6360 {
6367 /* This transformation is only worthwhile if we don't have to wrap
6368 arg in a SAVE_EXPR, and the operation can be simplified on at least
6369 one of the branches once its pushed inside the COND_EXPR. */
6374 {
6378 /* If this operand throws an expression, then it does not make
6379 sense to try to perform a logical or arithmetic operation
6380 involving it. */
6385 }
6386 else
6387 {
6392 }
6396 {
6400 else
6402 }
6404 {
6408 else
6410 }
6414 }
6416 \f
6417 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6419 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6420 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6421 ADDEND is the same as X.
6423 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6424 and finite. The problematic cases are when X is zero, and its mode
6425 has signed zeros. In the case of rounding towards -infinity,
6426 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6427 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6429 static bool
6431 {
6435 /* Don't allow the fold with -fsignaling-nans. */
6439 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6443 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6448 /* The mode has signed zeros, and we have to honor their sign.
6449 In this situation, there is only one case we can return true for.
6450 X - 0 is the same as X unless rounding towards -infinity is
6451 supported. */
6453 }
6455 /* Subroutine of fold() that checks comparisons of built-in math
6456 functions against real constants.
6458 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6459 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6460 is the type of the result and ARG0 and ARG1 are the operands of the
6461 comparison. ARG1 must be a TREE_REAL_CST.
6463 The function returns the constant folded tree if a simplification
6464 can be made, and NULL_TREE otherwise. */
6466 static tree
6469 {
6470 REAL_VALUE_TYPE c;
6473 {
6479 {
6480 /* sqrt(x) < y is always false, if y is negative. */
6484 /* sqrt(x) > y is always true, if y is negative and we
6485 don't care about NaNs, i.e. negative values of x. */
6489 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6492 }
6494 {
6495 REAL_VALUE_TYPE c2;
6501 {
6502 /* sqrt(x) > y is x == +Inf, when y is very large. */
6507 /* sqrt(x) > y is always false, when y is very large
6508 and we don't care about infinities. */
6510 }
6512 /* sqrt(x) > c is the same as x > c*c. */
6515 }
6517 {
6518 REAL_VALUE_TYPE c2;
6524 {
6525 /* sqrt(x) < y is always true, when y is a very large
6526 value and we don't care about NaNs or Infinities. */
6530 /* sqrt(x) < y is x != +Inf when y is very large and we
6531 don't care about NaNs. */
6536 /* sqrt(x) < y is x >= 0 when y is very large and we
6537 don't care about Infinities. */
6542 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6551 dconst0)),
6554 c2)));
6555 }
6557 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6562 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6565 {
6570 dconst0)),
6573 c2)));
6574 }
6575 }
6576 }
6579 }
6581 /* Subroutine of fold() that optimizes comparisons against Infinities,
6582 either +Inf or -Inf.
6584 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6585 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6586 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6588 The function returns the constant folded tree if a simplification
6589 can be made, and NULL_TREE otherwise. */
6591 static tree
6593 {
6595 REAL_VALUE_TYPE max;
6596 tree temp;
6601 /* For negative infinity swap the sense of the comparison. */
6607 {
6609 /* x > +Inf is always false, if with ignore sNANs. */
6615 /* x <= +Inf is always true, if we don't case about NaNs. */
6619 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6622 {
6625 }
6630 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6636 /* x < +Inf is always equal to x <= DBL_MAX. */
6642 /* x != +Inf is always equal to !(x > DBL_MAX). */
6654 }
6657 }
6659 /* Subroutine of fold() that optimizes comparisons of a division by
6660 a nonzero integer constant against an integer constant, i.e.
6661 X/C1 op C2.
6663 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6664 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6665 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6667 The function returns the constant folded tree if a simplification
6668 can be made, and NULL_TREE otherwise. */
6670 static tree
6672 {
6677 HOST_WIDE_INT hpart;
6682 /* We have to do this the hard way to detect unsigned overflow.
6683 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6694 {
6699 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6707 }
6709 {
6713 {
6732 }
6733 }
6734 else
6735 {
6736 /* A negative divisor reverses the relational operators. */
6742 {
6761 }
6762 }
6765 {
6786 {
6789 }
6794 {
6797 }
6802 {
6805 }
6810 {
6813 }
6818 }
6821 }
6824 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6825 equality/inequality test, then return a simplified form of the test
6826 using a sign testing. Otherwise return NULL. TYPE is the desired
6827 result type. */
6829 static tree
6831 tree result_type)
6832 {
6833 /* If this is testing a single bit, we can optimize the test. */
6837 {
6838 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6839 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6843 /* This is only a win if casting to a signed type is cheap,
6844 i.e. when arg00's type is not a partial mode. */
6847 {
6852 }
6853 }
6856 }
6858 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6859 equality/inequality test, then return a simplified form of
6860 the test using shifts and logical operations. Otherwise return
6861 NULL. TYPE is the desired result type. */
6863 tree
6865 tree result_type)
6866 {
6867 /* If this is testing a single bit, we can optimize the test. */
6871 {
6880 /* First, see if we can fold the single bit test into a sign-bit
6881 test. */
6883 result_type);
6887 /* Otherwise we have (A & C) != 0 where C is a single bit,
6888 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6889 Similarly for (A & C) == 0. */
6891 /* If INNER is a right shift of a constant and it plus BITNUM does
6892 not overflow, adjust BITNUM and INNER. */
6899 {
6902 }
6904 /* If we are going to be able to omit the AND below, we must do our
6905 operations as unsigned. If we must use the AND, we have a choice.
6906 Normally unsigned is faster, but for some machines signed is. */
6907 #ifdef LOAD_EXTEND_OP
6910 #else
6912 #endif
6928 /* Put the AND last so it can combine with more things. */
6931 /* Make sure to return the proper type. */
6935 }
6937 }
6939 /* Check whether we are allowed to reorder operands arg0 and arg1,
6940 such that the evaluation of arg1 occurs before arg0. */
6942 static bool
6944 {
6951 }
6953 /* Test whether it is preferable two swap two operands, ARG0 and
6954 ARG1, for example because ARG0 is an integer constant and ARG1
6955 isn't. If REORDER is true, only recommend swapping if we can
6956 evaluate the operands in reverse order. */
6958 bool
6960 {
6996 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6997 for commutative and comparison operators. Ensuring a canonical
6998 form allows the optimizers to find additional redundancies without
6999 having to explicitly check for both orderings. */
7005 /* Put SSA_NAMEs last. */
7011 /* Put variables last. */
7018 }
7020 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
7021 ARG0 is extended to a wider type. */
7023 static tree
7025 {
7027 tree arg1_unw;
7036 #ifdef HAVE_canonicalize_funcptr_for_compare
7037 /* Disable this optimization if we're casting a function pointer
7038 type on targets that require function pointer canonicalization. */
7043 #endif
7050 /* If possible, express the comparison in the shorter mode. */
7066 /* If we are comparing with the integer that does not fit into the range
7067 of the shorter type, the result is known. */
7078 {
7105 }
7108 }
7110 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
7111 ARG0 just the signedness is changed. */
7113 static tree
7116 {
7117 tree arg0_inner;
7128 #ifdef HAVE_canonicalize_funcptr_for_compare
7129 /* Disable this optimization if we're casting a function pointer
7130 type on targets that require function pointer canonicalization. */
7135 #endif
7155 else
7159 }
7161 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
7162 step of the array. Reconstructs s and delta in the case of s * delta
7163 being an integer constant (and thus already folded).
7164 ADDR is the address. MULT is the multiplicative expression.
7165 If the function succeeds, the new address expression is returned. Otherwise
7166 NULL_TREE is returned. */
7168 static tree
7170 {
7174 tree itype;
7177 /* Strip the nops that might be added when converting op1 to sizetype. */
7180 /* Canonicalize op1 into a possibly non-constant delta
7181 and an INTEGER_CST s. */
7183 {
7190 {
7193 }
7195 {
7198 }
7199 else
7201 }
7203 {
7206 }
7207 else
7208 {
7209 /* Simulate we are delta * 1. */
7212 }
7215 {
7217 {
7218 /* Remember if this was a multi-dimensional array. */
7231 {
7234 }
7235 else
7236 {
7237 /* Try if delta is a multiple of step. */
7242 }
7244 /* Only fold here if we can verify we do not overflow one
7245 dimension of a multi-dimensional array. */
7247 {
7248 tree tmp;
7264 }
7267 }
7268 else
7273 }
7275 /* We found the suitable array reference. So copy everything up to it,
7276 and replace the index. */
7283 {
7287 }
7295 }
7298 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7299 means A >= Y && A != MAX, but in this case we know that
7300 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7302 static tree
7304 {
7311 else
7320 {
7323 }
7325 {
7328 }
7329 else
7336 {
7337 /* Convert the pointer types into integer before taking the difference. */
7341 }
7342 else
7349 }
7351 /* Fold a sum or difference of at least one multiplication.
7352 Returns the folded tree or NULL if no simplification could be made. */
7354 static tree
7356 {
7360 /* (A * C) +- (B * C) -> (A+-B) * C.
7361 (A * C) +- A -> A * (C+-1).
7362 We are most concerned about the case where C is a constant,
7363 but other combinations show up during loop reduction. Since
7364 it is not difficult, try all four possibilities. */
7367 {
7370 }
7372 {
7375 }
7376 else
7377 {
7378 /* We cannot generate constant 1 for fract. */
7383 }
7385 {
7388 }
7390 {
7393 }
7394 else
7395 {
7396 /* We cannot generate constant 1 for fract. */
7401 }
7413 /* No identical multiplicands; see if we can find a common
7414 power-of-two factor in non-power-of-two multiplies. This
7415 can help in multi-dimensional array access. */
7418 {
7421 tree maybe_same;
7425 /* Move min of absolute values to int11. */
7428 {
7433 }
7434 else
7438 {
7446 }
7447 }
7457 }
7459 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7460 specified by EXPR into the buffer PTR of length LEN bytes.
7461 Return the number of bytes placed in the buffer, or zero
7462 upon failure. */
7464 static int
7466 {
7477 {
7481 else
7486 {
7493 else
7495 }
7496 else
7499 }
7501 }
7504 /* Subroutine of native_encode_expr. Encode the REAL_CST
7505 specified by EXPR into the buffer PTR of length LEN bytes.
7506 Return the number of bytes placed in the buffer, or zero
7507 upon failure. */
7509 static int
7511 {
7517 /* There are always 32 bits in each long, no matter the size of
7518 the hosts long. We handle floating point representations with
7519 up to 192 bits. */
7530 {
7535 {
7542 else
7544 }
7545 else
7548 }
7550 }
7552 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7553 specified by EXPR into the buffer PTR of length LEN bytes.
7554 Return the number of bytes placed in the buffer, or zero
7555 upon failure. */
7557 static int
7559 {
7561 tree part;
7572 }
7575 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7576 specified by EXPR into the buffer PTR of length LEN bytes.
7577 Return the number of bytes placed in the buffer, or zero
7578 upon failure. */
7580 static int
7582 {
7592 {
7594 {
7597 }
7598 else
7602 {
7605 }
7606 else
7607 {
7611 }
7613 }
7615 }
7618 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7619 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7620 buffer PTR of length LEN bytes. Return the number of bytes
7621 placed in the buffer, or zero upon failure. */
7623 int
7625 {
7627 {
7642 }
7643 }
7646 /* Subroutine of native_interpret_expr. Interpret the contents of
7647 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7648 If the buffer cannot be interpreted, return NULL_TREE. */
7650 static tree
7652 {
7666 {
7669 {
7676 else
7678 }
7679 else
7685 else
7688 }
7691 }
7694 /* Subroutine of native_interpret_expr. Interpret the contents of
7695 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7696 If the buffer cannot be interpreted, return NULL_TREE. */
7698 static tree
7700 {
7705 /* There are always 32 bits in each long, no matter the size of
7706 the hosts long. We handle floating point representations with
7707 up to 192 bits. */
7708 REAL_VALUE_TYPE r;
7719 {
7722 {
7729 else
7731 }
7732 else
7737 }
7741 }
7744 /* Subroutine of native_interpret_expr. Interpret the contents of
7745 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7746 If the buffer cannot be interpreted, return NULL_TREE. */
7748 static tree
7750 {
7765 }
7768 /* Subroutine of native_interpret_expr. Interpret the contents of
7769 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7770 If the buffer cannot be interpreted, return NULL_TREE. */
7772 static tree
7774 {
7786 {
7791 }
7793 }
7796 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7797 the buffer PTR of length LEN as a constant of type TYPE. For
7798 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7799 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7800 return NULL_TREE. */
7802 tree
7804 {
7806 {
7823 }
7824 }
7827 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7828 TYPE at compile-time. If we're unable to perform the conversion
7829 return NULL_TREE. */
7831 static tree
7833 {
7834 /* We support up to 512-bit values (for V8DFmode). */
7838 /* Check that the host and target are sane. */
7847 }
7849 /* Build an expression for the address of T. Folds away INDIRECT_REF
7850 to avoid confusing the gimplify process. When IN_FOLD is true
7851 avoid modifications of T. */
7853 static tree
7855 {
7856 /* The size of the object is not relevant when talking about its address. */
7860 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7863 {
7868 }
7870 {
7880 }
7881 else
7885 }
7887 /* Build an expression for the address of T with type PTRTYPE. This
7888 function modifies the input parameter 'T' by sometimes setting the
7889 TREE_ADDRESSABLE flag. */
7891 tree
7893 {
7895 }
7897 /* Build an expression for the address of T. This function modifies
7898 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7899 flag. When called from fold functions, use fold_addr_expr instead. */
7901 tree
7903 {
7907 }
7909 /* Same as build_fold_addr_expr, builds an expression for the address
7910 of T, but avoids touching the input node 't'. Fold functions
7911 should use this version. */
7913 static tree
7915 {
7919 }
7921 /* Fold a unary expression of code CODE and type TYPE with operand
7922 OP0. Return the folded expression if folding is successful.
7923 Otherwise, return NULL_TREE. */
7925 tree
7927 {
7928 tree tem;
7929 tree arg0;
7937 {
7940 {
7941 /* Don't use STRIP_NOPS, because signedness of argument type
7942 matters. */
7944 }
7945 else
7946 {
7947 /* Strip any conversions that don't change the mode. This
7948 is safe for every expression, except for a comparison
7949 expression because its signedness is derived from its
7950 operands.
7952 Note that this is done as an internal manipulation within
7953 the constant folder, in order to find the simplest
7954 representation of the arguments so that their form can be
7955 studied. In any cases, the appropriate type conversions
7956 should be put back in the tree that will get out of the
7957 constant folder. */
7959 }
7960 }
7963 {
7968 {
7978 /* If this was a conversion, and all we did was to move into
7979 inside the COND_EXPR, bring it back out. But leave it if
7980 it is a conversion from integer to integer and the
7981 result precision is no wider than a word since such a
7982 conversion is cheap and may be optimized away by combine,
7983 while it couldn't if it were outside the COND_EXPR. Then return
7984 so we don't get into an infinite recursion loop taking the
7985 conversion out and then back in. */
7997 && (INTEGRAL_TYPE_P
8009 }
8011 {
8013 {
8017 }
8021 integer_one_node),
8023 integer_zero_node));
8024 }
8025 }
8028 {
8036 /* If we have (type) (a CMP b) and type is an integral type, return
8037 new expression involving the new type. */
8042 /* Handle cases of two conversions in a row. */
8045 {
8067 /* In addition to the cases of two conversions in a row
8068 handled below, if we are converting something to its own
8069 type via an object of identical or wider precision, neither
8070 conversion is needed. */
8077 /* Likewise, if the intermediate and final types are either both
8078 float or both integer, we don't need the middle conversion if
8079 it is wider than the final type and doesn't change the signedness
8080 (for integers). Avoid this if the final type is a pointer
8081 since then we sometimes need the inner conversion. Likewise if
8082 the outer has a precision not equal to the size of its mode. */
8091 && ! final_ptr
8095 /* If we have a sign-extension of a zero-extended value, we can
8096 replace that by a single zero-extension. */
8102 /* Two conversions in a row are not needed unless:
8103 - some conversion is floating-point (overstrict for now), or
8104 - some conversion is a vector (overstrict for now), or
8105 - the intermediate type is narrower than both initial and
8106 final, or
8107 - the intermediate type and innermost type differ in signedness,
8108 and the outermost type is wider than the intermediate, or
8109 - the initial type is a pointer type and the precisions of the
8110 intermediate and final types differ, or
8111 - the final type is a pointer type and the precisions of the
8112 initial and intermediate types differ.
8113 - the initial type is a pointer to an array and the final type
8114 not. */
8131 }
8133 /* Handle (T *)&A.B.C for A being of type T and B and C
8134 living at offset zero. This occurs frequently in
8135 C++ upcasting and then accessing the base. */
8139 {
8141 tree offset;
8147 /* If the reference was to a (constant) zero offset, we can use
8148 the address of the base if it has the same base type
8149 as the result type. */
8154 }
8159 /* Detect assigning a bitfield. */
8161 && DECL_BIT_FIELD
8163 {
8164 /* Don't leave an assignment inside a conversion
8165 unless assigning a bitfield. */
8167 /* First do the assignment, then return converted constant. */
8172 }
8174 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
8175 constants (if x has signed type, the sign bit cannot be set
8176 in c). This folds extension into the BIT_AND_EXPR. */
8181 {
8191 <= HOST_BITS_PER_WIDE_INT
8193 {
8200 #ifdef LOAD_EXTEND_OP
8202 && !flag_syntax_only
8205 {
8209 }
8210 #endif
8211 }
8213 {
8219 }
8220 }
8222 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
8223 when one of the new casts will fold away. Conservatively we assume
8224 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
8230 {
8236 }
8238 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
8239 of the same precision, and X is an integer type not narrower than
8240 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
8247 {
8252 }
8284 /* Convert fabs((double)float) into (double)fabsf(float). */
8287 {
8292 targ0));
8293 }
8294 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8300 /* Strip sign ops from argument. */
8302 {
8306 }
8313 {
8318 }
8320 {
8325 }
8335 /* Convert ~ (-A) to A - 1. */
8340 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8348 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8361 /* Perform BIT_NOT_EXPR on each element individually. */
8363 {
8368 {
8370 {
8376 }
8377 else
8380 }
8383 }
8388 /* The argument to invert_truthvalue must have Boolean type. */
8392 /* Note that the operand of this must be an int
8393 and its values must be 0 or 1.
8394 ("true" is a fixed value perhaps depending on the language,
8395 but we don't handle values other than 1 correctly yet.) */
8410 {
8418 }
8420 {
8424 }
8426 {
8430 {
8439 }
8440 }
8452 {
8460 }
8462 {
8466 }
8468 {
8472 {
8481 }
8482 }
8488 }
8490 /* Fold a binary expression of code CODE and type TYPE with operands
8491 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8492 Return the folded expression if folding is successful. Otherwise,
8493 return NULL_TREE. */
8495 static tree
8497 {
8504 else
8507 /* MIN (MAX (a, b), b) == b. */
8512 /* MIN (MAX (b, a), b) == b. */
8518 /* MIN (a, MAX (a, b)) == a. */
8524 /* MIN (a, MAX (b, a)) == a. */
8531 }
8533 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8534 by changing CODE to reduce the magnitude of constants involved in
8535 ARG0 of the comparison.
8536 Returns a canonicalized comparison tree if a simplification was
8537 possible, otherwise returns NULL_TREE.
8538 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8539 valid if signed overflow is undefined. */
8541 static tree
8545 {
8551 /* Match A +- CST code arg1 and CST code arg1. */
8558 /* Identify the constant in arg0 and its sign. */
8561 else
8565 /* Overflowed constants and zero will cause problems. */
8570 /* See if we can reduce the magnitude of the constant in
8571 arg0 by changing the comparison code. */
8573 {
8574 /* CST <= arg1 -> CST-1 < arg1. */
8577 /* -CST < arg1 -> -CST-1 <= arg1. */
8580 /* CST > arg1 -> CST-1 >= arg1. */
8583 /* -CST >= arg1 -> -CST-1 > arg1. */
8586 else
8588 /* arg1 code' CST' might be more canonical. */
8590 }
8591 else
8592 {
8593 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8597 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8601 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8605 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8609 else
8612 }
8614 /* Now build the constant reduced in magnitude. */
8620 /* If swapping might yield to a more canonical form, do so. */
8623 else
8625 }
8627 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8628 overflow further. Try to decrease the magnitude of constants involved
8629 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8630 and put sole constants at the second argument position.
8631 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8633 static tree
8636 {
8637 tree t;
8642 /* In principle pointers also have undefined overflow behavior,
8643 but that causes problems elsewhere. */
8648 /* Try canonicalization by simplifying arg0. */
8653 {
8657 }
8659 /* Try canonicalization by simplifying arg1 using the swapped
8660 comparison. */
8668 }
8670 /* Subroutine of fold_binary. This routine performs all of the
8671 transformations that are common to the equality/inequality
8672 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8673 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8674 fold_binary should call fold_binary. Fold a comparison with
8675 tree code CODE and type TYPE with operands OP0 and OP1. Return
8676 the folded comparison or NULL_TREE. */
8678 static tree
8680 {
8693 /* If one arg is a real or integer constant, put it last. */
8697 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8704 {
8708 tree lhs;
8715 /* If the constant operation overflowed this can be
8716 simplified as a comparison against INT_MAX/INT_MIN. */
8719 {
8723 /* Get the sign of the constant on the lhs if the
8724 operation were VARIABLE + CONST1. */
8728 /* The sign of the constant determines if we overflowed
8729 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8730 Canonicalize to the INT_MIN overflow by swapping the comparison
8731 if necessary. */
8735 /* We now can look at the canonicalized case
8736 VARIABLE + 1 CODE2 INT_MIN
8737 and decide on the result. */
8746 }
8751 {
8753 "when changing X +- C1 cmp C2 to "
8755 WARN_STRICT_OVERFLOW_COMPARISON);
8757 }
8758 }
8760 /* For comparisons of pointers we can decompose it to a compile time
8761 comparison of the base objects and the offsets into the object.
8762 This requires at least one operand being an ADDR_EXPR or a
8763 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8769 {
8776 /* Get base and offset for the access. Strip ADDR_EXPR for
8777 get_inner_reference, but put it back by stripping INDIRECT_REF
8778 off the base object if possible. */
8781 {
8787 else
8789 }
8791 {
8794 }
8798 {
8802 /* We have to make sure to have an indirect/non-indirect base1
8803 just the same as we did for base0. */
8809 }
8811 {
8814 }
8818 /* If we have equivalent bases we might be able to simplify. */
8821 {
8822 /* We can fold this expression to a constant if the non-constant
8823 offset parts are equal. */
8827 {
8829 {
8843 }
8844 }
8845 /* We can simplify the comparison to a comparison of the variable
8846 offset parts if the constant offset parts are equal.
8847 Be careful to use signed size type here because otherwise we
8848 mess with array offsets in the wrong way. This is possible
8849 because pointer arithmetic is restricted to retain within an
8850 object and overflow on pointer differences is undefined as of
8851 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8853 {
8854 tree signed_size_type_node;
8857 /* By converting to signed size type we cover middle-end pointer
8858 arithmetic which operates on unsigned pointer types of size
8859 type size and ARRAY_REF offsets which are properly sign or
8860 zero extended from their type in case it is narrower than
8861 size type. */
8864 else
8868 else
8872 }
8873 }
8874 }
8876 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8877 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8878 the resulting offset is smaller in absolute value than the
8879 original one. */
8887 {
8892 tree cst;
8894 "occur when combining constants around "
8897 /* Put the constant on the side where it doesn't overflow and is
8898 of lower absolute value than before. */
8904 {
8907 variable1,
8910 }
8917 {
8922 variable2);
8923 }
8924 }
8926 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8927 signed arithmetic case. That form is created by the compiler
8928 often enough for folding it to be of value. One example is in
8929 computing loop trip counts after Operator Strength Reduction. */
8935 {
8944 "eliminating multiplication in comparison "
8946 WARN_STRICT_OVERFLOW_COMPARISON);
8948 /* If const1 is negative we swap the sense of the comparison. */
8953 }
8960 {
8968 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8973 /* (-a) CMP (-b) -> b CMP a */
8980 {
8981 REAL_VALUE_TYPE cst;
8984 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8991 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8992 /* a CMP (-0) -> a CMP 0 */
8997 /* x != NaN is always true, other ops are always false. */
9000 {
9003 }
9005 /* Fold comparisons against infinity. */
9007 {
9011 }
9012 }
9014 /* If this is a comparison of a real constant with a PLUS_EXPR
9015 or a MINUS_EXPR of a real constant, we can convert it into a
9016 comparison with a revised real constant as long as no overflow
9017 occurs when unsafe_math_optimizations are enabled. */
9029 /* Likewise, we can simplify a comparison of a real constant with
9030 a MINUS_EXPR whose first operand is also a real constant, i.e.
9031 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9032 floating-point types only if -fassociative-math is set. */
9043 /* Fold comparisons against built-in math functions. */
9045 && flag_unsafe_math_optimizations
9047 {
9051 {
9055 }
9056 }
9057 }
9062 {
9063 /* If we are widening one operand of an integer comparison,
9064 see if the other operand is similarly being widened. Perhaps we
9065 can do the comparison in the narrower type. */
9070 /* Or if we are changing signedness. */
9074 }
9076 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9077 constant, we can simplify it. */
9082 {
9086 }
9088 /* Simplify comparison of something with itself. (For IEEE
9089 floating-point, we can only do some of these simplifications.) */
9091 {
9093 {
9108 /* For NE, we can only do this simplification if integer
9109 or we don't honor IEEE floating point NaNs. */
9113 /* ... fall through ... */
9119 }
9120 }
9122 /* If we are comparing an expression that just has comparisons
9123 of two integer values, arithmetic expressions of those comparisons,
9124 and constants, we can simplify it. There are only three cases
9125 to check: the two values can either be equal, the first can be
9126 greater, or the second can be greater. Fold the expression for
9127 those three values. Since each value must be 0 or 1, we have
9128 eight possibilities, each of which corresponds to the constant 0
9129 or 1 or one of the six possible comparisons.
9131 This handles common cases like (a > b) == 0 but also handles
9132 expressions like ((x > y) - (y > x)) > 0, which supposedly
9133 occur in macroized code. */
9136 {
9141 /* Don't handle degenerate cases here; they should already
9142 have been handled anyway. */
9151 {
9155 /* We can't just pass T to eval_subst in case cval1 or cval2
9156 was the same as ARG1. */
9158 tree high_result
9162 arg1);
9163 tree equal_result
9167 arg1);
9168 tree low_result
9172 arg1);
9174 /* All three of these results should be 0 or 1. Confirm they are.
9175 Then use those values to select the proper code to use. */
9180 {
9181 /* Make a 3-bit mask with the high-order bit being the
9182 value for `>', the next for '=', and the low for '<'. */
9186 {
9188 /* Always false. */
9209 /* Always true. */
9211 }
9216 }
9217 }
9218 }
9220 /* Fold a comparison of the address of COMPONENT_REFs with the same
9221 type and component to a comparison of the address of the base
9222 object. In short, &x->a OP &y->a to x OP y and
9223 &x->a OP &y.a to x OP &y */
9228 {
9232 {
9238 }
9239 }
9241 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9242 into a single range test. */
9250 {
9254 }
9256 /* Fold ~X op ~Y as Y op X. */
9259 {
9264 }
9266 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9269 {
9275 }
9278 }
9281 /* Subroutine of fold_binary. Optimize complex multiplications of the
9282 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9283 argument EXPR represents the expression "z" of type TYPE. */
9285 static tree
9287 {
9292 {
9295 }
9297 {
9300 }
9301 else
9302 {
9306 }
9315 }
9318 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9319 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9320 guarantees that P and N have the same least significant log2(M) bits.
9321 N is not otherwise constrained. In particular, N is not normalized to
9322 0 <= N < M as is common. In general, the precise value of P is unknown.
9323 M is chosen as large as possible such that constant N can be determined.
9325 Returns M and sets *RESIDUE to N. */
9327 static unsigned HOST_WIDE_INT
9329 {
9336 {
9339 {
9341 tree offset;
9349 {
9352 else
9353 /* We don't handle more complicated offset expressions. */
9355 }
9356 }
9360 }
9362 {
9375 {
9378 }
9380 {
9383 {
9386 /* Compute the greatest power-of-2 divisor of op1. */
9390 /* If align is non-zero and less than *modulus, replace
9391 *modulus with align., If align is 0, then either op1 is 0
9392 or the greatest power-of-2 divisor of op1 doesn't fit in an
9393 unsigned HOST_WIDE_INT. In either case, no additional
9394 constraint is imposed. */
9399 }
9400 }
9401 }
9403 /* If we get here, we were unable to determine anything useful about the
9404 expression. */
9406 }
9409 /* Fold a binary expression of code CODE and type TYPE with operands
9410 OP0 and OP1. Return the folded expression if folding is
9411 successful. Otherwise, return NULL_TREE. */
9413 tree
9415 {
9430 /* Strip any conversions that don't change the mode. This is
9431 safe for every expression, except for a comparison expression
9432 because its signedness is derived from its operands. So, in
9433 the latter case, only strip conversions that don't change the
9434 signedness.
9436 Note that this is done as an internal manipulation within the
9437 constant folder, in order to find the simplest representation
9438 of the arguments so that their form can be studied. In any
9439 cases, the appropriate type conversions should be put back in
9440 the tree that will get out of the constant folder. */
9443 {
9446 }
9447 else
9448 {
9451 }
9453 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9454 constant but we can't do arithmetic on them. */
9461 {
9463 {
9464 /* Make sure type and arg0 have the same saturating flag. */
9468 }
9471 else
9475 {
9479 }
9480 }
9482 /* If this is a commutative operation, and ARG0 is a constant, move it
9483 to ARG1 to reduce the number of tests below. */
9488 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9490 First check for cases where an arithmetic operation is applied to a
9491 compound, conditional, or comparison operation. Push the arithmetic
9492 operation inside the compound or conditional to see if any folding
9493 can then be done. Convert comparison to conditional for this purpose.
9494 The also optimizes non-constant cases that used to be done in
9495 expand_expr.
9497 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9498 one of the operands is a comparison and the other is a comparison, a
9499 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9500 code below would make the expression more complex. Change it to a
9501 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9502 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9514 {
9518 boolean_type_node,
9526 }
9530 {
9536 op1));
9545 {
9551 }
9554 {
9560 }
9561 }
9564 {
9566 /* 0 +p index -> (type)index */
9570 /* PTR +p 0 -> PTR */
9574 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9581 /* index +p PTR -> PTR +p index */
9588 /* (PTR +p B) +p A -> PTR +p (B + A) */
9590 {
9591 tree inner;
9599 }
9601 /* PTR_CST +p CST -> CST1 */
9605 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9606 of the array. Loop optimizer sometimes produce this type of
9607 expressions. */
9609 {
9613 }
9618 /* PTR + INT -> (INT)(PTR p+ INT) */
9623 arg0,
9625 /* INT + PTR -> (INT)(PTR p+ INT) */
9630 arg1,
9632 /* A + (-B) -> A - B */
9637 /* (-A) + B -> B - A */
9645 {
9646 /* Convert ~A + 1 to -A. */
9651 /* ~X + X is -1. */
9654 {
9659 {
9662 }
9663 }
9665 /* X + ~X is -1. */
9668 {
9673 {
9676 }
9677 }
9679 /* X + (X / CST) * -CST is X % CST. */
9684 {
9692 }
9693 }
9695 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9696 same or one. Make sure type is not saturating.
9697 fold_plusminus_mult_expr will re-associate. */
9702 {
9706 }
9709 {
9713 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9714 with a constant, and the two constants have no bits in common,
9715 we should treat this as a BIT_IOR_EXPR since this may produce more
9716 simplifications. */
9724 {
9727 }
9729 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9730 (plus (plus (mult) (mult)) (foo)) so that we can
9731 take advantage of the factoring cases below. */
9738 {
9744 else
9766 parg1)));
9767 }
9768 }
9769 else
9770 {
9771 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9775 /* Likewise if the operands are reversed. */
9779 /* Convert X + -C into X - C. */
9782 {
9788 }
9790 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9791 to __complex__ ( x, y ). This is not the same for SNaNs or
9792 if signed zeros are involved. */
9796 {
9803 {
9807 {
9813 }
9815 {
9821 }
9822 }
9823 }
9831 /* Convert x+x into x*2.0. */
9837 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9838 We associate floats only if the user has specified
9839 -fassociative-math. */
9843 {
9848 {
9849 tree tree0;
9852 }
9853 }
9854 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9855 We associate floats only if the user has specified
9856 -fassociative-math. */
9860 {
9865 {
9866 tree tree0;
9869 }
9870 }
9871 }
9873 bit_rotate:
9874 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9875 is a rotate of A by C1 bits. */
9876 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9877 is a rotate of A by B bits. */
9878 {
9887 {
9906 {
9914 TYPE_PRECISION
9919 ? LROTATE_EXPR
9922 }
9924 {
9932 TYPE_PRECISION
9937 ? LROTATE_EXPR
9940 }
9941 }
9942 }
9944 associate:
9945 /* In most languages, can't associate operations on floats through
9946 parentheses. Rather than remember where the parentheses were, we
9947 don't associate floats at all, unless the user has specified
9948 -fassociative-math.
9949 And, we need to make sure type is not saturating. */
9953 {
9958 /* Split both trees into variables, constants, and literals. Then
9959 associate each group together, the constants with literals,
9960 then the result with variables. This increases the chances of
9961 literals being recombined later and of generating relocatable
9962 expressions for the sum of a constant and literal. */
9967 /* With undefined overflow we can only associate constants
9968 with one variable. */
9972 {
9980 /* The only case we can still associate with two variables
9981 is if they are the same, modulo negation. */
9984 }
9986 /* Only do something if we found more than two objects. Otherwise,
9987 nothing has changed and we risk infinite recursion. */
9993 {
9994 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10003 /* Preserve the MINUS_EXPR if the negative part of the literal is
10004 greater than the positive part. Otherwise, the multiplicative
10005 folding code (i.e extract_muldiv) may be fooled in case
10006 unsigned constants are subtracted, like in the following
10007 example: ((X*2 + 4) - 8U)/2. */
10009 {
10013 {
10017 }
10018 else
10019 {
10023 }
10024 }
10026 {
10031 else
10032 {
10038 }
10039 }
10044 }
10045 }
10050 /* Pointer simplifications for subtraction, simple reassociations. */
10052 {
10053 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10056 {
10064 }
10065 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10067 {
10073 }
10074 }
10075 /* A - (-B) -> A + B */
10079 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10088 /* Convert -A - 1 to ~A. */
10096 /* Convert -1 - A to ~A. */
10102 /* X - (X / CST) * CST is X % CST. */
10115 {
10121 /* Fold A - (A & B) into ~B & A. */
10124 {
10126 {
10131 }
10133 {
10138 }
10139 }
10141 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10142 any power of 2 minus 1. */
10147 {
10153 {
10157 }
10158 }
10159 }
10161 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10165 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10166 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10167 (-ARG1 + ARG0) reduces to -ARG1. */
10171 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10172 __complex__ ( x, -y ). This is not the same for SNaNs or if
10173 signed zeros are involved. */
10177 {
10184 {
10188 {
10190 arg1r ? arg1r
10195 }
10197 {
10201 arg1i ? arg1i
10204 }
10205 }
10206 }
10208 /* Fold &x - &x. This can happen from &x.foo - &x.
10209 This is unsafe for certain floats even in non-IEEE formats.
10210 In IEEE, it is unsafe because it does wrong for NaNs.
10211 Also note that operand_equal_p is always false if an operand
10212 is volatile. */
10218 /* A - B -> A + (-B) if B is easily negatable. */
10221 /* Avoid this transformation if B is a positive REAL_CST. */
10229 /* Try folding difference of addresses. */
10230 {
10231 HOST_WIDE_INT diff;
10237 }
10239 /* Fold &a[i] - &a[j] to i-j. */
10244 {
10249 {
10257 }
10258 }
10266 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10267 same or one. Make sure type is not saturating.
10268 fold_plusminus_mult_expr will re-associate. */
10273 {
10277 }
10282 /* (-A) * (-B) -> A * B */
10293 {
10298 /* Transform x * -1 into -x. Make sure to do the negation
10299 on the original operand with conversions not stripped
10300 because we can only strip non-sign-changing conversions. */
10303 /* Transform x * -C into -x * C if x is easily negatable. */
10312 /* (a * (1 << b)) is (a << b) */
10326 {
10329 "occur when simplifying "
10331 WARN_STRICT_OVERFLOW_MISC);
10333 }
10335 /* Optimize z * conj(z) for integer complex numbers. */
10342 }
10343 else
10344 {
10345 /* Maybe fold x * 0 to 0. The expressions aren't the same
10346 when x is NaN, since x * 0 is also NaN. Nor are they the
10347 same in modes with signed zeros, since multiplying a
10348 negative value by 0 gives -0, not +0. */
10353 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10358 /* Transform x * -1.0 into -x. */
10363 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10364 the result for floating point types due to rounding so it is applied
10365 only if -fassociative-math was specify. */
10370 {
10376 }
10378 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10380 {
10383 {
10386 }
10387 }
10389 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10390 This is not the same for NaNs or if signed zeros are
10391 involved. */
10397 {
10409 }
10411 /* Optimize z * conj(z) for floating point complex numbers.
10412 Guarded by flag_unsafe_math_optimizations as non-finite
10413 imaginary components don't produce scalar results. */
10424 {
10428 /* Optimizations of root(...)*root(...). */
10430 {
10435 /* Optimize sqrt(x)*sqrt(x) as x. */
10441 /* Optimize root(x)*root(y) as root(x*y). */
10445 }
10447 /* Optimize expN(x)*expN(y) as expN(x+y). */
10449 {
10455 }
10457 /* Optimizations of pow(...)*pow(...). */
10461 {
10467 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10469 {
10473 }
10475 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10477 {
10481 }
10482 }
10484 /* Optimize tan(x)*cos(x) as sin(x). */
10493 {
10498 }
10500 /* Optimize x*pow(x,c) as pow(x,c+1). */
10504 {
10510 {
10512 REAL_VALUE_TYPE c;
10513 tree arg;
10519 }
10520 }
10522 /* Optimize pow(x,c)*x as pow(x,c+1). */
10526 {
10532 {
10534 REAL_VALUE_TYPE c;
10535 tree arg;
10541 }
10542 }
10544 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10547 {
10551 {
10554 }
10555 }
10556 }
10557 }
10561 bit_ior:
10569 /* ~X | X is -1. */
10572 {
10576 }
10578 /* X | ~X is -1. */
10581 {
10585 }
10587 /* Canonicalize (X & C1) | C2. */
10591 {
10599 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10604 {
10608 }
10609 else
10610 {
10614 }
10616 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10621 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10622 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10623 mode which allows further optimizations. */
10633 {
10634 unsigned HOST_WIDE_INT mask
10638 {
10642 }
10643 }
10650 arg1);
10651 }
10653 /* (X & Y) | Y is (X, Y). */
10657 /* (X & Y) | X is (Y, X). */
10662 /* X | (X & Y) is (Y, X). */
10667 /* X | (Y & X) is (Y, X). */
10677 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10679 This results in more efficient code for machines without a NAND
10680 instruction. Combine will canonicalize to the first form
10681 which will allow use of NAND instructions provided by the
10682 backend if they exist. */
10685 {
10690 }
10692 /* See if this can be simplified into a rotate first. If that
10693 is unsuccessful continue in the association code. */
10704 /* ~X ^ X is -1. */
10707 {
10711 }
10713 /* X ^ ~X is -1. */
10716 {
10720 }
10722 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10723 with a constant, and the two constants have no bits in common,
10724 we should treat this as a BIT_IOR_EXPR since this may produce more
10725 simplifications. */
10733 {
10736 }
10738 /* (X | Y) ^ X -> Y & ~ X*/
10741 {
10744 arg1);
10748 }
10750 /* (Y | X) ^ X -> Y & ~ X*/
10753 {
10756 arg1);
10760 }
10762 /* X ^ (X | Y) -> Y & ~ X*/
10765 {
10768 arg0);
10772 }
10774 /* X ^ (Y | X) -> Y & ~ X*/
10777 {
10780 arg0);
10784 }
10786 /* Convert ~X ^ ~Y to X ^ Y. */
10793 /* Convert ~X ^ C to X ^ ~C. */
10800 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10807 /* Fold (X & Y) ^ Y as ~X & Y. */
10810 {
10815 }
10816 /* Fold (X & Y) ^ X as ~Y & X. */
10820 {
10825 }
10826 /* Fold X ^ (X & Y) as X & ~Y. */
10829 {
10834 }
10835 /* Fold X ^ (Y & X) as ~Y & X. */
10839 {
10844 }
10846 /* See if this can be simplified into a rotate first. If that
10847 is unsuccessful continue in the association code. */
10858 /* ~X & X is always zero. */
10863 /* X & ~X is always zero. */
10868 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10872 {
10881 }
10883 /* (X | Y) & Y is (X, Y). */
10887 /* (X | Y) & X is (Y, X). */
10892 /* X & (X | Y) is (Y, X). */
10897 /* X & (Y | X) is (Y, X). */
10903 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10907 {
10913 }
10914 /* Fold ~X & 1 as (X & 1) == 0. */
10917 {
10923 }
10925 /* Fold (X ^ Y) & Y as ~X & Y. */
10928 {
10933 }
10934 /* Fold (X ^ Y) & X as ~Y & X. */
10938 {
10943 }
10944 /* Fold X & (X ^ Y) as X & ~Y. */
10947 {
10952 }
10953 /* Fold X & (Y ^ X) as ~Y & X. */
10957 {
10962 }
10967 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10970 {
10971 unsigned int prec
10978 }
10980 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10982 This results in more efficient code for machines without a NOR
10983 instruction. Combine will canonicalize to the first form
10984 which will allow use of NOR instructions provided by the
10985 backend if they exist. */
10988 {
10995 }
10997 /* If arg0 is derived from the address of an object or function, we may
10998 be able to fold this expression using the object or function's
10999 alignment. */
11001 {
11007 /* This works because modulus is a power of 2. If this weren't the
11008 case, we'd have to replace it by its greatest power-of-2
11009 divisor: modulus & -modulus. */
11012 }
11014 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
11015 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
11016 if the new mask might be further optimized. */
11025 {
11027 unsigned HOST_WIDE_INT mask
11037 {
11040 /* See if more bits can be proven as zero because of
11041 zero extension. */
11044 {
11049 {
11051 /* See if we can shorten the right shift. */
11054 }
11055 }
11059 /* For arithmetic shift if sign bit could be set, zerobits
11060 can contain actually sign bits, so no transformation is
11061 possible, unless MASK masks them all away. In that
11062 case the shift needs to be converted into logical shift. */
11065 {
11068 else
11070 }
11071 }
11073 /* ((X << 16) & 0xff00) is (X, 0). */
11079 {
11082 /* Only do the transformation if NEWMASK is some integer
11083 mode's mask. */
11090 {
11092 {
11098 }
11099 else
11103 newmask));
11104 }
11105 }
11106 }
11111 /* Don't touch a floating-point divide by zero unless the mode
11112 of the constant can represent infinity. */
11118 /* Optimize A / A to 1.0 if we don't care about
11119 NaNs or Infinities. Skip the transformation
11120 for non-real operands. */
11125 {
11129 }
11131 /* The complex version of the above A / A optimization. */
11134 {
11138 {
11140 /* omit_two_operands will call fold_convert for us. */
11142 }
11143 }
11145 /* (-A) / (-B) -> A / B */
11155 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11160 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11165 /* If ARG1 is a constant, we can convert this to a multiply by the
11166 reciprocal. This does not have the same rounding properties,
11167 so only do this if -freciprocal-math. We can actually
11168 always safely do it if ARG1 is a power of two, but it's hard to
11169 tell if it is or not in a portable manner. */
11171 {
11176 /* Find the reciprocal if optimizing and the result is exact. */
11178 {
11179 REAL_VALUE_TYPE r;
11182 {
11186 }
11187 }
11188 }
11189 /* Convert A/B/C to A/(B*C). */
11196 /* Convert A/(B/C) to (A/B)*C. */
11204 /* Convert C1/(X*C2) into (C1/C2)/X. */
11209 {
11215 }
11218 {
11222 /* Optimize sin(x)/cos(x) as tan(x). */
11228 {
11233 }
11235 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11241 {
11245 {
11249 }
11250 }
11252 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11253 NaNs or Infinities. */
11257 {
11264 {
11269 }
11270 }
11272 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11273 NaNs or Infinities. */
11277 {
11284 {
11288 {
11292 tmp);
11293 }
11294 }
11295 }
11297 /* Optimize pow(x,c)/x as pow(x,c-1). */
11301 {
11307 {
11309 REAL_VALUE_TYPE c;
11310 tree arg;
11316 }
11317 }
11319 /* Optimize a/root(b/c) into a*root(c/b). */
11321 {
11325 {
11334 }
11335 }
11337 /* Optimize x/expN(y) into x*expN(-y). */
11339 {
11344 }
11346 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11350 {
11357 }
11358 }
11363 /* Simplify A / (B << N) where A and B are positive and B is
11364 a power of 2, to A >> (N + log2(B)). */
11369 {
11372 {
11379 WARN_STRICT_OVERFLOW_MISC);
11385 }
11386 }
11388 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11389 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11395 /* Fall thru */
11404 /* X / -1 is -X. */
11411 /* Convert -A / -B to A / B when the type is signed and overflow is
11412 undefined. */
11416 {
11419 "when distributing negation across "
11421 WARN_STRICT_OVERFLOW_MISC);
11425 }
11429 {
11432 "when distributing negation across "
11434 WARN_STRICT_OVERFLOW_MISC);
11437 }
11439 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11440 operation, EXACT_DIV_EXPR.
11442 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11443 At one time others generated faster code, it's not clear if they do
11444 after the last round to changes to the DIV code in expmed.c. */
11453 {
11457 WARN_STRICT_OVERFLOW_MISC);
11459 }
11467 /* X % 1 is always zero, but be sure to preserve any side
11468 effects in X. */
11472 /* X % 0, return X % 0 unchanged so that we can get the
11473 proper warnings and errors. */
11477 /* 0 % X is always zero, but be sure to preserve any side
11478 effects in X. Place this after checking for X == 0. */
11482 /* X % -1 is zero. */
11489 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11490 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11495 {
11497 /* Also optimize A % (C << N) where C is a power of 2,
11498 to A & ((C << N) - 1). */
11503 {
11508 "occur when simplifying "
11510 WARN_STRICT_OVERFLOW_MISC);
11514 }
11515 }
11517 /* X % -C is the same as X % C. */
11524 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11529 /* X % -Y is the same as X % Y. */
11540 {
11544 WARN_STRICT_OVERFLOW_MISC);
11546 }
11557 /* Optimize -1 >> x for arithmetic right shifts. */
11560 /* ... fall through ... */
11563 shift:
11569 /* Since negative shift count is not well-defined,
11570 don't try to compute it in the compiler. */
11574 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11579 {
11583 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11584 being well defined. */
11586 {
11591 else
11593 }
11597 }
11599 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11600 into x & ((unsigned)-1 >> c) for unsigned types. */
11608 {
11611 tree lshift;
11612 tree arg00;
11615 {
11622 }
11623 }
11625 /* Rewrite an LROTATE_EXPR by a constant into an
11626 RROTATE_EXPR by a new constant. */
11628 {
11633 }
11635 /* If we have a rotate of a bit operation with the rotate count and
11636 the second operand of the bit operation both constant,
11637 permute the two operations. */
11649 /* Two consecutive rotates adding up to the width of the mode can
11650 be ignored. */
11661 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11662 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11663 if the latter can be further optimized. */
11668 {
11671 arg1);
11674 arg1);
11678 }
11706 /* Note that the operands of this must be ints
11707 and their values must be 0 or 1.
11708 ("true" is a fixed value perhaps depending on the language.) */
11709 /* If first arg is constant zero, return it. */
11713 /* If either arg is constant true, drop it. */
11717 /* Preserve sequence points. */
11720 /* If second arg is constant zero, result is zero, but first arg
11721 must be evaluated. */
11724 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11725 case will be handled here. */
11729 /* !X && X is always false. */
11733 /* X && !X is always false. */
11738 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11739 means A >= Y && A != MAX, but in this case we know that
11740 A < X <= MAX. */
11744 {
11752 }
11754 truth_andor:
11755 /* We only do these simplifications if we are optimizing. */
11759 /* Check for things like (A || B) && (A || C). We can convert this
11760 to A || (B && C). Note that either operator can be any of the four
11761 truth and/or operations and the transformation will still be
11762 valid. Also note that we only care about order for the
11763 ANDIF and ORIF operators. If B contains side effects, this
11764 might change the truth-value of A. */
11771 {
11791 /* This case if tricky because we must either have commutative
11792 operators or else A10 must not have side-effects. */
11798 a01);
11799 }
11801 /* See if we can build a range comparison. */
11805 /* Check for the possibility of merging component references. If our
11806 lhs is another similar operation, try to merge its rhs with our
11807 rhs. Then try to merge our lhs and rhs. */
11819 /* Note that the operands of this must be ints
11820 and their values must be 0 or true.
11821 ("true" is a fixed value perhaps depending on the language.) */
11822 /* If first arg is constant true, return it. */
11826 /* If either arg is constant zero, drop it. */
11830 /* Preserve sequence points. */
11833 /* If second arg is constant true, result is true, but we must
11834 evaluate first arg. */
11837 /* Likewise for first arg, but note this only occurs here for
11838 TRUTH_OR_EXPR. */
11842 /* !X || X is always true. */
11846 /* X || !X is always true. */
11854 /* If the second arg is constant zero, drop it. */
11857 /* If the second arg is constant true, this is a logical inversion. */
11859 {
11860 /* Only call invert_truthvalue if operand is a truth value. */
11863 else
11866 }
11867 /* Identical arguments cancel to zero. */
11871 /* !X ^ X is always true. */
11876 /* X ^ !X is always true. */
11889 /* bool_var != 0 becomes bool_var. */
11894 /* bool_var == 1 becomes bool_var. */
11899 /* bool_var != 1 becomes !bool_var. */
11904 /* bool_var == 0 becomes !bool_var. */
11909 /* If this is an equality comparison of the address of two non-weak,
11910 unaliased symbols neither of which are extern (since we do not
11911 have access to attributes for externs), then we know the result. */
11924 {
11925 /* We know that we're looking at the address of two
11926 non-weak, unaliased, static _DECL nodes.
11928 It is both wasteful and incorrect to call operand_equal_p
11929 to compare the two ADDR_EXPR nodes. It is wasteful in that
11930 all we need to do is test pointer equality for the arguments
11931 to the two ADDR_EXPR nodes. It is incorrect to use
11932 operand_equal_p as that function is NOT equivalent to a
11933 C equality test. It can in fact return false for two
11934 objects which would test as equal using the C equality
11935 operator. */
11939 type);
11940 }
11942 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11943 a MINUS_EXPR of a constant, we can convert it into a comparison with
11944 a revised constant as long as no overflow occurs. */
11956 /* Similarly for a NEGATE_EXPR. */
11964 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11973 /* Transform comparisons of the form X +- C CMP X. */
11979 {
11986 else
11989 }
11991 /* If we have X - Y == 0, we can convert that to X == Y and similarly
11992 for !=. Don't do this for ordered comparisons due to overflow. */
11998 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
12003 /* If this is an EQ or NE comparison with zero and ARG0 is
12004 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12005 two operations, but the latter can be done in one less insn
12006 on machines that have only two-operand insns or on which a
12007 constant cannot be the first operand. */
12010 {
12015 {
12022 }
12025 {
12032 }
12033 }
12035 /* If this is an NE or EQ comparison of zero against the result of a
12036 signed MOD operation whose second operand is a power of 2, make
12037 the MOD operation unsigned since it is simpler and equivalent. */
12045 {
12055 }
12057 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12058 C1 is a valid shift constant, and C2 is a power of two, i.e.
12059 a single bit. */
12063 == INTEGER_CST
12066 {
12071 /* Check for a valid shift count. */
12074 {
12078 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12079 can be rewritten as (X & (C2 << C1)) != 0. */
12081 {
12085 }
12086 /* Otherwise, for signed (arithmetic) shifts,
12087 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12088 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12092 /* Otherwise, of unsigned (logical) shifts,
12093 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12094 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12095 else
12099 arg000);
12100 }
12101 }
12103 /* If this is an NE comparison of zero with an AND of one, remove the
12104 comparison since the AND will give the correct value. */
12111 /* If we have (A & C) == C where C is a power of 2, convert this into
12112 (A & C) != 0. Similarly for NE_EXPR. */
12118 integer_zero_node));
12120 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12121 bit, then fold the expression into A < 0 or A >= 0. */
12126 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12127 Similarly for NE_EXPR. */
12131 {
12140 }
12142 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12143 Similarly for NE_EXPR. */
12147 {
12154 }
12156 /* If this is a comparison of a field, we may be able to simplify it. */
12159 /* Handle the constant case even without -O
12160 to make sure the warnings are given. */
12162 {
12166 }
12168 /* Optimize comparisons of strlen vs zero to a compare of the
12169 first character of the string vs zero. To wit,
12170 strlen(ptr) == 0 => *ptr == 0
12171 strlen(ptr) != 0 => *ptr != 0
12172 Other cases should reduce to one of these two (or a constant)
12173 due to the return value of strlen being unsigned. */
12176 {
12184 {
12188 }
12189 }
12191 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12192 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12196 {
12203 {
12205 {
12208 }
12211 }
12212 }
12214 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12220 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12225 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12232 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12240 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12241 (X & C) == 0 when C is a single bit. */
12246 {
12252 }
12254 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12255 constant C is a power of two, i.e. a single bit. */
12262 {
12266 }
12268 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12269 when is C is a power of two, i.e. a single bit. */
12276 {
12282 }
12286 {
12289 }
12291 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12298 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12301 {
12313 arg01),
12321 arg01),
12329 arg00),
12337 arg00),
12339 }
12343 {
12350 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12351 operand_equal_p guarantees no side-effects so we don't need
12352 to use omit_one_operand on Z. */
12362 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12369 arg10);
12370 }
12372 /* Attempt to simplify equality/inequality comparisons of complex
12373 values. Only lower the comparison if the result is known or
12374 can be simplified to a single scalar comparison. */
12379 {
12384 {
12387 }
12388 else
12389 {
12392 }
12395 {
12398 }
12399 else
12400 {
12403 }
12407 {
12409 {
12414 }
12415 else
12416 {
12421 }
12422 }
12426 {
12428 {
12433 }
12434 else
12435 {
12440 }
12441 }
12442 }
12454 /* Transform comparisons of the form X +- C CMP X. */
12461 {
12468 else
12471 /* (X - c) > X becomes false. */
12475 {
12479 "occur when assuming that (X - c) > X "
12481 WARN_STRICT_OVERFLOW_ALL);
12483 }
12485 /* Likewise (X + c) < X becomes false. */
12489 {
12493 "occur when assuming that "
12495 WARN_STRICT_OVERFLOW_ALL);
12497 }
12499 /* Convert (X - c) <= X to true. */
12504 {
12508 "occur when assuming that "
12510 WARN_STRICT_OVERFLOW_ALL);
12512 }
12514 /* Convert (X + c) >= X to true. */
12519 {
12523 "occur when assuming that "
12525 WARN_STRICT_OVERFLOW_ALL);
12527 }
12530 {
12531 /* Convert X + c > X and X - c < X to true for integers. */
12535 {
12538 "not occur when assuming that "
12540 WARN_STRICT_OVERFLOW_ALL);
12542 }
12547 {
12550 "not occur when assuming that "
12552 WARN_STRICT_OVERFLOW_ALL);
12554 }
12556 /* Convert X + c <= X and X - c >= X to false for integers. */
12560 {
12563 "not occur when assuming that "
12565 WARN_STRICT_OVERFLOW_ALL);
12567 }
12572 {
12575 "not occur when assuming that "
12577 WARN_STRICT_OVERFLOW_ALL);
12579 }
12580 }
12581 }
12583 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
12584 This transformation affects the cases which are handled in later
12585 optimizations involving comparisons with non-negative constants. */
12589 {
12591 {
12596 }
12598 {
12603 }
12604 }
12606 /* Comparisons with the highest or lowest possible integer of
12607 the specified precision will have known values. */
12608 {
12616 {
12617 HOST_WIDE_INT signed_max_hi;
12622 {
12629 {
12633 }
12634 else
12635 {
12639 }
12640 }
12641 else
12642 {
12651 {
12654 }
12655 else
12656 {
12659 }
12660 }
12665 {
12678 /* The GE_EXPR and LT_EXPR cases above are not normally
12679 reached because of previous transformations. */
12683 }
12685 == max_hi
12688 {
12694 arg1);
12700 arg1);
12703 }
12705 == min_hi
12708 {
12723 }
12725 == min_hi
12728 {
12733 arg1);
12738 arg1);
12741 }
12746 /* We will flip the signedness of the comparison operator
12747 associated with the mode of arg1, so the sign bit is
12748 specified by this mode. Check that arg1 is the signed
12749 max associated with this sign bit. */
12751 /* signed_type does not work on pointer types. */
12753 {
12754 /* The following case also applies to X < signed_max+1
12755 and X >= signed_max+1 because previous transformations. */
12757 {
12758 tree st;
12763 }
12764 }
12765 }
12766 }
12768 /* If we are comparing an ABS_EXPR with a constant, we can
12769 convert all the cases into explicit comparisons, but they may
12770 well not be faster than doing the ABS and one comparison.
12771 But ABS (X) <= C is a range comparison, which becomes a subtraction
12772 and a comparison, and is probably faster. */
12786 /* Convert ABS_EXPR<x> >= 0 to true. */
12793 {
12796 "when simplifying comparison of "
12798 WARN_STRICT_OVERFLOW_CONDITIONAL);
12800 }
12802 /* Convert ABS_EXPR<x> < 0 to false. */
12807 {
12810 "when simplifying comparison of "
12812 WARN_STRICT_OVERFLOW_CONDITIONAL);
12814 }
12816 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12817 and similarly for >= into !=. */
12833 return
12852 {
12856 }
12858 /* If the first operand is NaN, the result is constant. */
12862 {
12864 ? integer_zero_node
12867 }
12869 /* If the second operand is NaN, the result is constant. */
12873 {
12875 ? integer_zero_node
12878 }
12880 /* Simplify unordered comparison of something with itself. */
12886 && !flag_trapping_math
12890 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12891 {
12902 }
12907 /* When pedantic, a compound expression can be neither an lvalue
12908 nor an integer constant expression. */
12911 /* Don't let (0, 0) be null pointer constant. */
12925 /* An ASSERT_EXPR should never be passed to fold_binary. */
12931 }
12933 /* Callback for walk_tree, looking for LABEL_EXPR.
12934 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12935 Do not check the sub-tree of GOTO_EXPR. */
12937 static tree
12941 {
12943 {
12948 /* no break */
12951 }
12952 }
12954 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12955 accessible from outside the sub-tree. Returns NULL_TREE if no
12956 addressable label is found. */
12958 static bool
12960 {
12962 }
12964 /* Fold a ternary expression of code CODE and type TYPE with operands
12965 OP0, OP1, and OP2. Return the folded expression if folding is
12966 successful. Otherwise, return NULL_TREE. */
12968 tree
12970 {
12971 tree tem;
12978 /* Strip any conversions that don't change the mode. This is safe
12979 for every expression, except for a comparison expression because
12980 its signedness is derived from its operands. So, in the latter
12981 case, only strip conversions that don't change the signedness.
12983 Note that this is done as an internal manipulation within the
12984 constant folder, in order to find the simplest representation of
12985 the arguments so that their form can be studied. In any cases,
12986 the appropriate type conversions should be put back in the tree
12987 that will get out of the constant folder. */
12989 {
12992 }
12995 {
12998 }
13001 {
13005 {
13011 }
13015 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
13016 so all simple results must be passed through pedantic_non_lvalue. */
13018 {
13021 /* Only optimize constant conditions when the selected branch
13022 has the same type as the COND_EXPR. This avoids optimizing
13023 away "c ? x : throw", where the throw has a void type.
13024 Avoid throwing away that operand which contains label. */
13031 }
13035 /* If we have A op B ? A : C, we may be able to convert this to a
13036 simpler expression, depending on the operation and the values
13037 of B and C. Signed zeros prevent all of these transformations,
13038 for reasons given above each one.
13040 Also try swapping the arguments and inverting the conditional. */
13045 {
13049 }
13053 op2,
13056 {
13059 {
13063 }
13064 }
13066 /* If the second operand is simpler than the third, swap them
13067 since that produces better jump optimization results. */
13070 {
13071 /* See if this can be inverted. If it can't, possibly because
13072 it was a floating-point inequality comparison, don't do
13073 anything. */
13077 }
13079 /* Convert A ? 1 : 0 to simply A. */
13082 /* If we try to convert OP0 to our type, the
13083 call to fold will try to move the conversion inside
13084 a COND, which will recurse. In that case, the COND_EXPR
13085 is probably the best choice, so leave it alone. */
13089 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13090 over COND_EXPR in cases such as floating point comparisons. */
13097 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13102 {
13103 /* sign_bit_p only checks ARG1 bits within A's precision.
13104 If <sign bit of A> has wider type than A, bits outside
13105 of A's precision in <sign bit of A> need to be checked.
13106 If they are all 0, this optimization needs to be done
13107 in unsigned A's type, if they are all 1 in signed A's type,
13108 otherwise this can't be done. */
13113 {
13115 HOST_WIDE_INT mask_hi;
13117 tree tem_type;
13125 {
13129 }
13130 else
13131 {
13135 }
13137 {
13141 }
13142 else
13148 {
13151 }
13154 {
13157 }
13158 else
13160 }
13167 arg1)));
13168 }
13170 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13171 already handled above. */
13176 {
13185 }
13187 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13188 is probably obsolete because the first operand should be a
13189 truth value (that's why we have the two cases above), but let's
13190 leave it in until we can confirm this for all front-ends. */
13201 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13207 arg1);
13209 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13213 {
13214 /* Only perform transformation if ARG0 is easily inverted. */
13219 arg1);
13220 }
13222 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13226 {
13227 /* Only perform transformation if ARG0 is easily inverted. */
13232 op2);
13233 }
13235 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13241 op2);
13246 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13247 of fold_ternary on them. */
13256 {
13265 {
13270 else
13271 {
13273 tree value;
13277 }
13282 else
13284 }
13285 }
13291 }
13293 /* Perform constant folding and related simplification of EXPR.
13294 The related simplifications include x*1 => x, x*0 => 0, etc.,
13295 and application of the associative law.
13296 NOP_EXPR conversions may be removed freely (as long as we
13297 are careful not to change the type of the overall expression).
13298 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13299 but we can constant-fold them if they have constant operands. */
13301 #ifdef ENABLE_FOLD_CHECKING
13302 # define fold(x) fold_1 (x)
13304 static
13305 #endif
13306 tree
13308 {
13312 tree tem;
13314 /* Return right away if a constant. */
13318 /* CALL_EXPR-like objects with variable numbers of operands are
13319 treated specially. */
13321 {
13323 {
13326 }
13328 }
13332 {
13337 {
13355 }
13356 }
13359 {
13366 }
13368 #ifdef ENABLE_FOLD_CHECKING
13369 #undef fold
13375 /* When --enable-checking=fold, compute a digest of expr before
13376 and after actual fold call to see if fold did not accidentally
13377 change original expr. */
13379 tree
13381 {
13382 tree ret;
13385 htab_t ht;
13404 }
13406 void
13408 {
13411 htab_t ht;
13421 }
13423 static void
13425 {
13427 }
13429 static void
13431 {
13437 recursive_label:
13451 {
13452 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13456 }
13461 {
13462 /* Allow these fields to be modified. */
13463 tree tmp;
13470 {
13473 }
13474 }
13483 {
13486 {
13500 }
13504 {
13517 }
13534 {
13540 }
13545 {
13549 }
13560 {
13563 }
13573 }
13574 }
13576 /* Helper function for outputting the checksum of a tree T. When
13577 debugging with gdb, you can "define mynext" to be "next" followed
13578 by "call debug_fold_checksum (op0)", then just trace down till the
13579 outputs differ. */
13581 void
13583 {
13598 }
13600 #endif
13602 /* Fold a unary tree expression with code CODE of type TYPE with an
13603 operand OP0. Return a folded expression if successful. Otherwise,
13604 return a tree expression with code CODE of type TYPE with an
13605 operand OP0. */
13607 tree
13609 {
13610 tree tem;
13611 #ifdef ENABLE_FOLD_CHECKING
13614 htab_t ht;
13621 #endif
13627 #ifdef ENABLE_FOLD_CHECKING
13635 #endif
13637 }
13639 /* Fold a binary tree expression with code CODE of type TYPE with
13640 operands OP0 and OP1. Return a folded expression if successful.
13641 Otherwise, return a tree expression with code CODE of type TYPE
13642 with operands OP0 and OP1. */
13644 tree
13646 MEM_STAT_DECL)
13647 {
13648 tree tem;
13649 #ifdef ENABLE_FOLD_CHECKING
13655 htab_t ht;
13667 #endif
13673 #ifdef ENABLE_FOLD_CHECKING
13689 #endif
13691 }
13693 /* Fold a ternary tree expression with code CODE of type TYPE with
13694 operands OP0, OP1, and OP2. Return a folded expression if
13695 successful. Otherwise, return a tree expression with code CODE of
13696 type TYPE with operands OP0, OP1, and OP2. */
13698 tree
13700 MEM_STAT_DECL)
13701 {
13702 tree tem;
13703 #ifdef ENABLE_FOLD_CHECKING
13711 htab_t ht;
13728 #endif
13735 #ifdef ENABLE_FOLD_CHECKING
13759 #endif
13761 }
13763 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13764 arguments in ARGARRAY, and a null static chain.
13765 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13766 of type TYPE from the given operands as constructed by build_call_array. */
13768 tree
13770 {
13771 tree tem;
13772 #ifdef ENABLE_FOLD_CHECKING
13778 htab_t ht;
13792 #endif
13796 #ifdef ENABLE_FOLD_CHECKING
13813 #endif
13815 }
13817 /* Perform constant folding and related simplification of initializer
13818 expression EXPR. These behave identically to "fold_buildN" but ignore
13819 potential run-time traps and exceptions that fold must preserve. */
13821 #define START_FOLD_INIT \
13822 int saved_signaling_nans = flag_signaling_nans;\
13823 int saved_trapping_math = flag_trapping_math;\
13824 int saved_rounding_math = flag_rounding_math;\
13825 int saved_trapv = flag_trapv;\
13826 int saved_folding_initializer = folding_initializer;\
13827 flag_signaling_nans = 0;\
13828 flag_trapping_math = 0;\
13829 flag_rounding_math = 0;\
13830 flag_trapv = 0;\
13831 folding_initializer = 1;
13833 #define END_FOLD_INIT \
13834 flag_signaling_nans = saved_signaling_nans;\
13835 flag_trapping_math = saved_trapping_math;\
13836 flag_rounding_math = saved_rounding_math;\
13837 flag_trapv = saved_trapv;\
13838 folding_initializer = saved_folding_initializer;
13840 tree
13842 {
13843 tree result;
13844 START_FOLD_INIT;
13848 END_FOLD_INIT;
13850 }
13852 tree
13854 {
13855 tree result;
13856 START_FOLD_INIT;
13860 END_FOLD_INIT;
13862 }
13864 tree
13866 tree op2)
13867 {
13868 tree result;
13869 START_FOLD_INIT;
13873 END_FOLD_INIT;
13875 }
13877 tree
13880 {
13881 tree result;
13882 START_FOLD_INIT;
13886 END_FOLD_INIT;
13888 }
13890 #undef START_FOLD_INIT
13891 #undef END_FOLD_INIT
13893 /* Determine if first argument is a multiple of second argument. Return 0 if
13894 it is not, or we cannot easily determined it to be.
13896 An example of the sort of thing we care about (at this point; this routine
13897 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13898 fold cases do now) is discovering that
13900 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13902 is a multiple of
13904 SAVE_EXPR (J * 8)
13906 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13908 This code also handles discovering that
13910 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13912 is a multiple of 8 so we don't have to worry about dealing with a
13913 possible remainder.
13915 Note that we *look* inside a SAVE_EXPR only to determine how it was
13916 calculated; it is not safe for fold to do much of anything else with the
13917 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13918 at run time. For example, the latter example above *cannot* be implemented
13919 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13920 evaluation time of the original SAVE_EXPR is not necessarily the same at
13921 the time the new expression is evaluated. The only optimization of this
13922 sort that would be valid is changing
13924 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13926 divided by 8 to
13928 SAVE_EXPR (I) * SAVE_EXPR (J)
13930 (where the same SAVE_EXPR (J) is used in the original and the
13931 transformed version). */
13933 int
13935 {
13943 {
13945 /* Bitwise and provides a power of two multiple. If the mask is
13946 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13949 /* FALLTHRU */
13962 {
13966 /* const_binop may not detect overflow correctly,
13967 so check for it explicitly here. */
13973 size_one_node,
13977 }
13981 /* Can't handle conversions from non-integral or wider integral type. */
13987 /* .. fall through ... */
14004 }
14005 }
14007 /* Return true if `t' is known to be non-negative. If the return
14008 value is based on the assumption that signed overflow is undefined,
14009 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14010 *STRICT_OVERFLOW_P. */
14012 bool
14014 {
14022 {
14024 /* Query VRP to see if it has recorded any information about
14025 the range of this object. */
14029 /* We can't return 1 if flag_wrapv is set because
14030 ABS_EXPR<INT_MIN> = INT_MIN. */
14034 {
14037 }
14053 strict_overflow_p)
14055 strict_overflow_p));
14057 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14058 both unsigned and at least 2 bits shorter than the result. */
14062 {
14067 {
14071 }
14072 }
14077 {
14078 /* x * x for floating point x is always non-negative. */
14082 strict_overflow_p)
14084 strict_overflow_p));
14085 }
14087 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14088 both unsigned and their total bits is shorter than the result. */
14092 {
14099 }
14105 strict_overflow_p)
14107 strict_overflow_p));
14118 strict_overflow_p)
14120 strict_overflow_p));
14131 strict_overflow_p);
14137 strict_overflow_p);
14141 strict_overflow_p);
14145 strict_overflow_p)
14147 strict_overflow_p));
14150 {
14155 {
14158 strict_overflow_p);
14160 {
14164 strict_overflow_p);
14165 }
14166 }
14168 {
14171 strict_overflow_p);
14175 }
14176 }
14180 {
14184 /* If the initializer is non-void, then it's a normal expression
14185 that will be assigned to the slot. */
14189 /* Otherwise, the initializer sets the slot in some way. One common
14190 way is an assignment statement at the end of the initializer. */
14192 {
14200 else
14202 }
14207 strict_overflow_p);
14210 }
14213 {
14217 {
14235 /* Always true. */
14239 /* sqrt(-0.0) is -0.0. */
14243 strict_overflow_p);
14276 /* True if the 1st argument is nonnegative. */
14278 strict_overflow_p);
14281 /* True if the 1st OR 2nd arguments are nonnegative. */
14283 strict_overflow_p)
14285 strict_overflow_p)));
14288 /* True if the 1st AND 2nd arguments are nonnegative. */
14290 strict_overflow_p)
14292 strict_overflow_p)));
14295 /* True if the 2nd argument is nonnegative. */
14297 strict_overflow_p);
14300 /* True if the 1st argument is nonnegative or the second
14301 argument is an even integer. */
14303 {
14307 }
14309 strict_overflow_p);
14312 /* True if the 1st argument is nonnegative or the second
14313 argument is an even integer valued real. */
14315 {
14316 REAL_VALUE_TYPE c;
14317 HOST_WIDE_INT n;
14322 {
14323 REAL_VALUE_TYPE cint;
14328 }
14329 }
14331 strict_overflow_p);
14335 }
14336 }
14338 /* ... fall through ... */
14341 {
14345 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14346 have a signed:1 type (where the value is -1 and 0). */
14348 }
14349 }
14351 /* We don't know sign of `t', so be conservative and return false. */
14353 }
14355 /* Return true if `t' is known to be non-negative. Handle warnings
14356 about undefined signed overflow. */
14358 bool
14360 {
14367 "determining that expression is always "
14369 WARN_STRICT_OVERFLOW_MISC);
14371 }
14373 /* Return true when T is an address and is known to be nonzero.
14374 For floating point we further ensure that T is not denormal.
14375 Similar logic is present in nonzero_address in rtlanal.h.
14377 If the return value is based on the assumption that signed overflow
14378 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14379 change *STRICT_OVERFLOW_P. */
14381 bool
14383 {
14387 /* Doing something useful for floating point would need more work. */
14392 {
14394 /* Query VRP to see if it has recorded any information about
14395 the range of this object. */
14400 strict_overflow_p);
14408 {
14409 /* With the presence of negative values it is hard
14410 to say something. */
14417 /* One of operands must be positive and the other non-negative. */
14418 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14419 overflows, on a twos-complement machine the sum of two
14420 nonnegative numbers can never be zero. */
14422 strict_overflow_p)
14424 strict_overflow_p));
14425 }
14430 {
14432 strict_overflow_p)
14434 strict_overflow_p))
14435 {
14438 }
14439 }
14443 {
14449 strict_overflow_p));
14450 }
14454 {
14460 /* Weak declarations may link to NULL. */
14464 /* Constants are never weak. */
14469 }
14477 {
14481 }
14490 {
14493 }
14500 {
14504 /* When both operands are nonzero, then MAX must be too. */
14506 strict_overflow_p))
14509 /* MAX where operand 0 is positive is positive. */
14511 strict_overflow_p);
14512 }
14513 /* MAX where operand 1 is positive is positive. */
14518 {
14522 }
14530 strict_overflow_p);
14535 strict_overflow_p);
14539 strict_overflow_p)
14541 strict_overflow_p));
14548 }
14550 }
14552 /* Return true when T is an address and is known to be nonzero.
14553 Handle warnings about undefined signed overflow. */
14555 bool
14557 {
14564 "determining that expression is always "
14566 WARN_STRICT_OVERFLOW_MISC);
14568 }
14570 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14571 attempt to fold the expression to a constant without modifying TYPE,
14572 OP0 or OP1.
14574 If the expression could be simplified to a constant, then return
14575 the constant. If the expression would not be simplified to a
14576 constant, then return NULL_TREE. */
14578 tree
14580 {
14583 }
14585 /* Given the components of a unary expression CODE, TYPE and OP0,
14586 attempt to fold the expression to a constant without modifying
14587 TYPE or OP0.
14589 If the expression could be simplified to a constant, then return
14590 the constant. If the expression would not be simplified to a
14591 constant, then return NULL_TREE. */
14593 tree
14595 {
14598 }
14600 /* If EXP represents referencing an element in a constant string
14601 (either via pointer arithmetic or array indexing), return the
14602 tree representing the value accessed, otherwise return NULL. */
14604 tree
14606 {
14610 {
14612 tree index;
14613 tree string;
14617 else
14618 {
14622 /* Optimize the special-case of a zero lower bound.
14624 We convert the low_bound to sizetype to avoid some problems
14625 with constant folding. (E.g. suppose the lower bound is 1,
14626 and its mode is QI. Without the conversion,l (ARRAY
14627 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14628 +INDEX), which becomes (ARRAY+255+INDEX). Opps!) */
14633 }
14646 }
14648 }
14650 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14651 an integer constant, real, or fixed-point constant.
14653 TYPE is the type of the result. */
14655 static tree
14657 {
14661 {
14663 {
14665 HOST_WIDE_INT high;
14673 }
14680 {
14681 FIXED_VALUE_TYPE f;
14686 /* Propagate overflow flags. */
14688 {
14691 }
14695 }
14699 }
14702 }
14704 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14705 an integer constant or real constant.
14707 TYPE is the type of the result. */
14709 tree
14711 {
14715 {
14717 /* If the value is unsigned, then the absolute value is
14718 the same as the ordinary value. */
14721 /* Similarly, if the value is non-negative. */
14724 /* If the value is negative, then the absolute value is
14725 its negation. */
14726 else
14727 {
14729 HOST_WIDE_INT high;
14735 }
14741 else
14747 }
14750 }
14752 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14753 constant. TYPE is the type of the result. */
14755 static tree
14757 {
14767 }
14769 /* Given CODE, a relational operator, the target type, TYPE and two
14770 constant operands OP0 and OP1, return the result of the
14771 relational operation. If the result is not a compile time
14772 constant, then return NULL_TREE. */
14774 static tree
14776 {
14779 /* From here on, the only cases we handle are when the result is
14780 known to be a constant. */
14783 {
14787 /* Handle the cases where either operand is a NaN. */
14789 {
14791 {
14819 }
14822 }
14825 }
14828 {
14832 }
14834 /* Handle equality/inequality of complex constants. */
14836 {
14847 else
14849 }
14851 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14853 To compute GT, swap the arguments and do LT.
14854 To compute GE, do LT and invert the result.
14855 To compute LE, swap the arguments, do LT and invert the result.
14856 To compute NE, do EQ and invert the result.
14858 Therefore, the code below must handle only EQ and LT. */
14861 {
14866 }
14868 /* Note that it is safe to invert for real values here because we
14869 have already handled the one case that it matters. */
14873 {
14876 }
14878 /* Compute a result for LT or EQ if args permit;
14879 Otherwise return T. */
14881 {
14886 else
14888 }
14889 else
14895 }
14897 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14898 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14899 itself. */
14901 tree
14903 {
14904 /* If the expression does not have side effects then we don't have to wrap
14905 it with a cleanup point expression. */
14909 /* If the expression is a return, check to see if the expression inside the
14910 return has no side effects or the right hand side of the modify expression
14911 inside the return. If either don't have side effects set we don't need to
14912 wrap the expression in a cleanup point expression. Note we don't check the
14913 left hand side of the modify because it should always be a return decl. */
14915 {
14922 }
14925 }
14927 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14928 of an indirection through OP0, or NULL_TREE if no simplification is
14929 possible. */
14931 tree
14933 {
14935 tree subtype;
14943 {
14946 /* *&CONST_DECL -> to the value of the const decl. */
14949 /* *&p => p; make sure to handle *&"str"[cst] here. */
14951 {
14955 else
14957 }
14958 /* *(foo *)&fooarray => fooarray[0] */
14961 {
14967 }
14968 /* *(foo *)&complexfoo => __real__ complexfoo */
14972 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14975 {
14979 }
14980 }
14982 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14985 {
14988 tree op00type;
14995 {
14999 }
15000 }
15002 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15005 {
15006 tree type_domain;
15013 }
15016 }
15018 /* Builds an expression for an indirection through T, simplifying some
15019 cases. */
15021 tree
15023 {
15029 else
15031 }
15033 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15035 tree
15037 {
15042 else
15044 }
15046 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15047 whose result is ignored. The type of the returned tree need not be
15048 the same as the original expression. */
15050 tree
15052 {
15058 {
15069 else
15075 {
15091 }
15096 }
15097 }
15099 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15100 This can only be applied to objects of a sizetype. */
15102 tree
15104 {
15111 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15112 have to do anything. Only do this when we are not given a const,
15113 because in that case, this check is more expensive than just
15114 doing it. */
15116 {
15121 }
15123 /* If divisor is a power of two, simplify this to bit manipulation. */
15125 {
15127 {
15140 {
15141 high++;
15144 }
15148 }
15149 else
15150 {
15151 tree t;
15157 }
15158 }
15159 else
15160 {
15165 }
15168 }
15170 /* Likewise, but round down. */
15172 tree
15174 {
15181 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15182 have to do anything. Only do this when we are not given a const,
15183 because in that case, this check is more expensive than just
15184 doing it. */
15186 {
15191 }
15193 /* If divisor is a power of two, simplify this to bit manipulation. */
15195 {
15196 tree t;
15200 }
15201 else
15202 {
15207 }
15210 }
15212 /* Returns the pointer to the base of the object addressed by EXP and
15213 extracts the information about the offset of the access, storing it
15214 to PBITPOS and POFFSET. */
15216 static tree
15219 {
15220 tree core;
15223 HOST_WIDE_INT bitsize;
15226 {
15231 }
15232 else
15233 {
15237 }
15240 }
15242 /* Returns true if addresses of E1 and E2 differ by a constant, false
15243 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15245 bool
15247 {
15261 {
15271 }
15273 {
15274 /* If only one of the offsets is non-constant, the difference cannot
15275 be a constant. */
15277 }
15278 else
15283 }
15285 /* Simplify the floating point expression EXP when the sign of the
15286 result is not significant. Return NULL_TREE if no simplification
15287 is possible. */
15289 tree
15291 {
15295 {
15330 {
15333 {
15335 /* Strip copysign function call, return the 1st argument. */
15341 /* Strip sign ops from the argument of "odd" math functions. */
15343 {
15347 }
15349 }
15350 }
15355 }
15357 }