| blob | 5a101f27451359f5f172d483cf761fa7d9e77db2 |
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. */
69 /* Nonzero if we are folding constants inside an initializer; zero
70 otherwise. */
73 /* The following constants represent a bit based encoding of GCC's
74 comparison operators. This encoding simplifies transformations
75 on relational comparison operators, such as AND and OR. */
93 };
124 tree);
145 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
146 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
147 and SUM1. Then this yields nonzero if overflow occurred during the
148 addition.
150 Overflow occurs if A and B have the same sign, but A and SUM differ in
151 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
152 sign. */
153 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
154 \f
155 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
156 We do that by representing the two-word integer in 4 words, with only
157 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
158 number. The value of the word is LOWPART + HIGHPART * BASE. */
160 #define LOWPART(x) \
161 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
162 #define HIGHPART(x) \
163 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
164 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
166 /* Unpack a two-word integer into 4 words.
167 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
168 WORDS points to the array of HOST_WIDE_INTs. */
170 static void
172 {
177 }
179 /* Pack an array of 4 words into a two-word integer.
180 WORDS points to the array of words.
181 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
183 static void
186 {
189 }
190 \f
191 /* Force the double-word integer L1, H1 to be within the range of the
192 integer type TYPE. Stores the properly truncated and sign-extended
193 double-word integer in *LV, *HV. Returns true if the operation
194 overflows, that is, argument and result are different. */
196 int
199 {
208 else
211 /* Size types *are* sign extended. */
216 /* First clear all bits that are beyond the type's precision. */
218 ;
221 else
222 {
226 }
228 /* Then do sign extension if necessary. */
234 {
235 /* Sign extend top half? */
239 }
241 {
244 }
245 else
246 {
247 /* Sign extend bottom half? */
249 {
252 }
253 }
258 /* If the value didn't fit, signal overflow. */
260 }
262 /* We force the double-int HIGH:LOW to the range of the type TYPE by
263 sign or zero extending it.
264 OVERFLOWABLE indicates if we are interested
265 in overflow of the value, when >0 we are only interested in signed
266 overflow, for <0 we are interested in any overflow. OVERFLOWED
267 indicates whether overflow has already occurred. CONST_OVERFLOWED
268 indicates whether constant overflow has already occurred. We force
269 T's value to be within range of T's type (by setting to 0 or 1 all
270 the bits outside the type's range). We set TREE_OVERFLOWED if,
271 OVERFLOWED is nonzero,
272 or OVERFLOWABLE is >0 and signed overflow occurs
273 or OVERFLOWABLE is <0 and any overflow occurs
274 We return a new tree node for the extended double-int. The node
275 is shared if no overflow flags are set. */
277 tree
281 {
285 /* Size types *are* sign extended. */
292 /* If we need to set overflow flags, return a new unshared node. */
294 {
298 {
305 }
306 }
308 /* Else build a shared node. */
310 }
311 \f
312 /* Add two doubleword integers with doubleword result.
313 Return nonzero if the operation overflows according to UNSIGNED_P.
314 Each argument is given as two `HOST_WIDE_INT' pieces.
315 One argument is L1 and H1; the other, L2 and H2.
316 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
318 int
323 {
325 HOST_WIDE_INT h;
335 else
337 }
339 /* Negate a doubleword integer with doubleword result.
340 Return nonzero if the operation overflows, assuming it's signed.
341 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
342 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
344 int
347 {
349 {
353 }
354 else
355 {
359 }
360 }
361 \f
362 /* Multiply two doubleword integers with doubleword result.
363 Return nonzero if the operation overflows according to UNSIGNED_P.
364 Each argument is given as two `HOST_WIDE_INT' pieces.
365 One argument is L1 and H1; the other, L2 and H2.
366 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
368 int
373 {
388 {
391 {
393 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
395 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
399 }
401 }
406 /* Unsigned overflow is immediate. */
410 /* Check for signed overflow by calculating the signed representation of the
411 top half of the result; it should agree with the low half's sign bit. */
413 {
416 }
418 {
421 }
423 }
424 \f
425 /* Shift the doubleword integer in L1, H1 left by COUNT places
426 keeping only PREC bits of result.
427 Shift right if COUNT is negative.
428 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
429 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
431 void
435 {
439 {
442 }
448 {
449 /* Shifting by the host word size is undefined according to the
450 ANSI standard, so we must handle this as a special case. */
453 }
455 {
458 }
459 else
460 {
464 }
466 /* Sign extend all bits that are beyond the precision. */
474 ;
476 {
479 }
480 else
481 {
485 }
486 }
488 /* Shift the doubleword integer in L1, H1 right by COUNT places
489 keeping only PREC bits of result. COUNT must be positive.
490 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
491 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
493 void
498 {
501 signmask = (arith
509 {
510 /* Shifting by the host word size is undefined according to the
511 ANSI standard, so we must handle this as a special case. */
514 }
516 {
519 }
520 else
521 {
525 }
527 /* Zero / sign extend all bits that are beyond the precision. */
530 {
533 }
535 ;
537 {
540 }
541 else
542 {
546 }
547 }
548 \f
549 /* Rotate the doubleword integer in L1, H1 left by COUNT places
550 keeping only PREC bits of result.
551 Rotate right if COUNT is negative.
552 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
554 void
558 {
570 }
572 /* Rotate the doubleword integer in L1, H1 left by COUNT places
573 keeping only PREC bits of result. COUNT must be positive.
574 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
576 void
580 {
592 }
593 \f
594 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
595 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
596 CODE is a tree code for a kind of division, one of
597 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
598 or EXACT_DIV_EXPR
599 It controls how the quotient is rounded to an integer.
600 Return nonzero if the operation overflows.
601 UNS nonzero says do unsigned division. */
603 int
606 HOST_WIDE_INT hnum_orig,
608 HOST_WIDE_INT hden_orig,
612 {
628 /* Calculate quotient sign and convert operands to unsigned. */
630 {
632 {
634 /* (minimum integer) / (-1) is the only overflow case. */
638 }
640 {
643 }
644 }
649 /* This unsigned division rounds toward zero. */
652 }
656 /* hden != 0 already checked. */
661 }
671 /* Special code for when the divisor < BASE. */
673 {
674 /* hnum != 0 already checked. */
676 {
680 }
681 }
682 else
683 {
684 /* Full double precision division,
685 with thanks to Don Knuth's "Seminumerical Algorithms". */
689 /* Find the highest nonzero divisor digit. */
692 {
695 }
697 /* Insure that the first digit of the divisor is at least BASE/2.
698 This is required by the quotient digit estimation algorithm. */
705 {
709 }
714 {
719 }
720 }
724 /* Main loop */
726 {
727 /* Guess the next quotient digit, quo_est, by dividing the first
728 two remaining dividend digits by the high order quotient digit.
729 quo_est is never low and is at most 2 high. */
736 else
739 /* Refine quo_est so it's usually correct, and at most one high. */
744 quo_est--;
746 /* Try QUO_EST as the quotient digit, by multiplying the
747 divisor by QUO_EST and subtracting from the remaining dividend.
748 Keep in mind that QUO_EST is the I - 1st digit. */
752 {
758 }
760 /* If quo_est was high by one, then num[i] went negative and
761 we need to correct things. */
763 {
764 quo_est--;
767 {
771 }
774 }
776 /* Store the quotient digit. */
778 }
779 }
783 finish_up:
784 /* If result is negative, make it so. */
788 /* Compute trial remainder: rem = num - (quo * den) */
794 {
803 {
804 /* quo = quo - 1; */
807 }
808 else
815 {
818 }
819 else
825 {
831 /* Get absolute values. */
837 /* If (2 * abs (lrem) >= abs (lden)) */
846 {
848 /* quo = quo - 1; */
851 else
852 /* quo = quo + 1; */
855 }
856 else
858 }
863 }
865 /* Compute true remainder: rem = num - (quo * den) */
870 }
872 /* If ARG2 divides ARG1 with zero remainder, carries out the division
873 of type CODE and returns the quotient.
874 Otherwise returns NULL_TREE. */
876 static tree
878 {
888 /* &obj[0] + -128 really should be compiled as &obj[-8] rather than
889 &obj[some_exotic_number]. */
891 {
895 type);
896 }
897 else
908 }
909 \f
910 /* This is nonzero if we should defer warnings about undefined
911 overflow. This facility exists because these warnings are a
912 special case. The code to estimate loop iterations does not want
913 to issue any warnings, since it works with expressions which do not
914 occur in user code. Various bits of cleanup code call fold(), but
915 only use the result if it has certain characteristics (e.g., is a
916 constant); that code only wants to issue a warning if the result is
917 used. */
921 /* If a warning about undefined overflow is deferred, this is the
922 warning. Note that this may cause us to turn two warnings into
923 one, but that is fine since it is sufficient to only give one
924 warning per expression. */
928 /* If a warning about undefined overflow is deferred, this is the
929 level at which the warning should be emitted. */
933 /* Start deferring overflow warnings. We could use a stack here to
934 permit nested calls, but at present it is not necessary. */
936 void
938 {
940 }
942 /* Stop deferring overflow warnings. If there is a pending warning,
943 and ISSUE is true, then issue the warning if appropriate. STMT is
944 the statement with which the warning should be associated (used for
945 location information); STMT may be NULL. CODE is the level of the
946 warning--a warn_strict_overflow_code value. This function will use
947 the smaller of CODE and the deferred code when deciding whether to
948 issue the warning. CODE may be zero to mean to always use the
949 deferred code. */
951 void
953 {
955 location_t locus;
960 {
966 }
977 /* Use the smallest code level when deciding to issue the
978 warning. */
987 else
990 }
992 /* Stop deferring overflow warnings, ignoring any deferred
993 warnings. */
995 void
997 {
999 }
1001 /* Whether we are deferring overflow warnings. */
1003 bool
1005 {
1007 }
1009 /* This is called when we fold something based on the fact that signed
1010 overflow is undefined. */
1012 static void
1014 {
1017 {
1020 {
1023 }
1024 }
1027 }
1028 \f
1029 /* Return true if the built-in mathematical function specified by CODE
1030 is odd, i.e. -f(x) == f(-x). */
1032 static bool
1034 {
1036 {
1070 }
1072 }
1074 /* Check whether we may negate an integer constant T without causing
1075 overflow. */
1077 bool
1079 {
1082 tree type;
1092 {
1097 }
1098 else
1103 }
1105 /* Determine whether an expression T can be cheaply negated using
1106 the function negate_expr without introducing undefined overflow. */
1108 static bool
1110 {
1111 tree type;
1120 {
1125 /* Check that -CST will not overflow type. */
1151 /* -(A + B) -> (-B) - A. */
1156 /* -(A + B) -> (-A) - B. */
1160 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
1170 /* Fall through. */
1183 /* In general we can't negate A / B, because if A is INT_MIN and
1184 B is 1, we may turn this into INT_MIN / -1 which is undefined
1185 and actually traps on some architectures. But if overflow is
1186 undefined, we can negate, because - (INT_MIN / 1) is an
1187 overflow. */
1195 /* Negate -((double)float) as (double)(-float). */
1197 {
1201 }
1205 /* Negate -f(x) as f(-x). */
1211 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1213 {
1219 }
1224 }
1226 }
1228 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
1229 simplification is possible.
1230 If negate_expr_p would return true for T, NULL_TREE will never be
1231 returned. */
1233 static tree
1235 {
1237 tree tem;
1240 {
1241 /* Convert - (~A) to A + 1. */
1257 /* Two's complement FP formats, such as c4x, may overflow. */
1267 {
1276 }
1298 {
1299 /* -(A + B) -> (-B) - A. */
1303 {
1307 }
1309 /* -(A + B) -> (-A) - B. */
1311 {
1315 }
1316 }
1320 /* - (A - B) -> B - A */
1332 /* Fall through. */
1336 {
1345 }
1353 /* In general we can't negate A / B, because if A is INT_MIN and
1354 B is 1, we may turn this into INT_MIN / -1 which is undefined
1355 and actually traps on some architectures. But if overflow is
1356 undefined, we can negate, because - (INT_MIN / 1) is an
1357 overflow. */
1359 {
1364 {
1371 }
1374 {
1381 }
1382 }
1386 /* Convert -((double)float) into (double)(-float). */
1388 {
1392 }
1396 /* Negate -f(x) as f(-x). */
1399 {
1405 }
1409 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1411 {
1416 {
1423 }
1424 }
1429 }
1432 }
1434 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
1435 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
1436 return NULL_TREE. */
1438 static tree
1440 {
1453 }
1454 \f
1455 /* Split a tree IN into a constant, literal and variable parts that could be
1456 combined with CODE to make IN. "constant" means an expression with
1457 TREE_CONSTANT but that isn't an actual constant. CODE must be a
1458 commutative arithmetic operation. Store the constant part into *CONP,
1459 the literal in *LITP and return the variable part. If a part isn't
1460 present, set it to null. If the tree does not decompose in this way,
1461 return the entire tree as the variable part and the other parts as null.
1463 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
1464 case, we negate an operand that was subtracted. Except if it is a
1465 literal for which we use *MINUS_LITP instead.
1467 If NEGATE_P is true, we are negating all of IN, again except a literal
1468 for which we use *MINUS_LITP instead.
1470 If IN is itself a literal or constant, return it as appropriate.
1472 Note that we do not guarantee that any of the three values will be the
1473 same type as IN, but they will have the same signedness and mode. */
1475 static tree
1478 {
1485 /* Strip any conversions that don't change the machine mode or signedness. */
1494 /* We can associate addition and subtraction together (even
1495 though the C standard doesn't say so) for integers because
1496 the value is not affected. For reals, the value might be
1497 affected, so we can't. */
1500 {
1506 /* First see if either of the operands is a literal, then a constant. */
1519 /* If we haven't dealt with either operand, this is not a case we can
1520 decompose. Otherwise, VAR is either of the ones remaining, if any. */
1525 else
1528 /* Now do any needed negations. */
1535 }
1538 else
1542 {
1549 }
1552 }
1554 /* Re-associate trees split by the above function. T1 and T2 are either
1555 expressions to associate or null. Return the new expression, if any. If
1556 we build an operation, do it in TYPE and with CODE. */
1558 static tree
1560 {
1566 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
1567 try to fold this since we will have infinite recursion. But do
1568 deal with any NEGATE_EXPRs. */
1571 {
1573 {
1582 }
1584 {
1587 }
1591 }
1595 }
1596 \f
1597 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1598 for use in int_const_binop, size_binop and size_diffop. */
1600 static bool
1602 {
1609 {
1618 }
1623 }
1626 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1627 to produce a new constant. Return NULL_TREE if we don't know how
1628 to evaluate CODE at compile-time.
1630 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1632 tree
1634 {
1638 HOST_WIDE_INT hi;
1640 HOST_WIDE_INT garbageh;
1641 tree t;
1644 int is_sizetype
1654 {
1670 /* It's unclear from the C standard whether shifts can overflow.
1671 The following code ignores overflow; perhaps a C standard
1672 interpretation ruling is needed. */
1701 /* This is a shortcut for a common special case. */
1706 {
1712 }
1714 /* ... fall through ... */
1720 {
1723 }
1726 {
1729 }
1736 /* This is a shortcut for a common special case. */
1741 {
1746 }
1748 /* ... fall through ... */
1766 else
1772 else
1778 }
1781 {
1784 /* Propagate overflow flags ourselves. */
1787 {
1790 }
1791 }
1792 else
1798 }
1800 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1801 constant. We assume ARG1 and ARG2 have the same data type, or at least
1802 are the same kind of constant and the same machine mode. Return zero if
1803 combining the constants is not allowed in the current operating mode.
1805 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1807 static tree
1809 {
1810 /* Sanity check for the recursive cases. */
1821 {
1823 REAL_VALUE_TYPE d1;
1824 REAL_VALUE_TYPE d2;
1825 REAL_VALUE_TYPE value;
1826 REAL_VALUE_TYPE result;
1830 /* The following codes are handled by real_arithmetic. */
1832 {
1843 }
1851 /* Don't perform operation if we honor signaling NaNs and
1852 either operand is a NaN. */
1857 /* Don't perform operation if it would raise a division
1858 by zero exception. */
1864 /* If either operand is a NaN, just return it. Otherwise, set up
1865 for floating-point trap; we return an overflow. */
1874 /* Don't constant fold this floating point operation if
1875 the result has overflowed and flag_trapping_math. */
1883 /* Don't constant fold this floating point operation if the
1884 result may dependent upon the run-time rounding mode and
1885 flag_rounding_math is set, or if GCC's software emulation
1886 is unable to accurately represent the result. */
1897 }
1900 {
1901 FIXED_VALUE_TYPE f1;
1902 FIXED_VALUE_TYPE f2;
1903 FIXED_VALUE_TYPE result;
1908 /* The following codes are handled by fixed_arithmetic. */
1910 {
1927 }
1934 /* Propagate overflow flags. */
1936 {
1939 }
1943 }
1946 {
1955 {
1966 notrunc);
1970 notrunc);
1974 {
1975 tree magsquared
1979 notrunc);
1980 tree t1
1984 notrunc);
1985 tree t2
1989 notrunc);
1996 }
2001 }
2005 }
2008 }
2010 /* Create a size type INT_CST node with NUMBER sign extended. KIND
2011 indicates which particular sizetype to create. */
2013 tree
2015 {
2017 }
2018 \f
2019 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2020 is a tree code. The type of the result is taken from the operands.
2021 Both must be equivalent integer types, ala int_binop_types_match_p.
2022 If the operands are constant, so is the result. */
2024 tree
2026 {
2035 /* Handle the special case of two integer constants faster. */
2037 {
2038 /* And some specific cases even faster than that. */
2040 {
2045 }
2047 {
2050 }
2052 {
2055 }
2057 /* Handle general case of two integer constants. */
2059 }
2062 }
2064 /* Given two values, either both of sizetype or both of bitsizetype,
2065 compute the difference between the two values. Return the value
2066 in signed type corresponding to the type of the operands. */
2068 tree
2070 {
2072 tree ctype;
2077 /* If the type is already signed, just do the simple thing. */
2085 else
2088 /* If either operand is not a constant, do the conversions to the signed
2089 type and subtract. The hardware will do the right thing with any
2090 overflow in the subtraction. */
2095 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2096 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2097 overflow) and negate (which can't either). Special-case a result
2098 of zero while we're here. */
2103 else
2107 }
2108 \f
2109 /* A subroutine of fold_convert_const handling conversions of an
2110 INTEGER_CST to another integer type. */
2112 static tree
2114 {
2115 tree t;
2117 /* Given an integer constant, make new constant with new type,
2118 appropriately sign-extended or truncated. */
2121 /* Don't set the overflow when
2122 converting from a pointer, */
2124 /* or to a sizetype with same signedness
2125 and the precision is unchanged.
2126 ??? sizetype is always sign-extended,
2127 but its signedness depends on the
2128 frontend. Thus we see spurious overflows
2129 here if we do not check this. */
2144 }
2146 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2147 to an integer type. */
2149 static tree
2151 {
2153 tree t;
2155 /* The following code implements the floating point to integer
2156 conversion rules required by the Java Language Specification,
2157 that IEEE NaNs are mapped to zero and values that overflow
2158 the target precision saturate, i.e. values greater than
2159 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2160 are mapped to INT_MIN. These semantics are allowed by the
2161 C and C++ standards that simply state that the behavior of
2162 FP-to-integer conversion is unspecified upon overflow. */
2165 REAL_VALUE_TYPE r;
2169 {
2176 }
2178 /* If R is NaN, return zero and show we have an overflow. */
2180 {
2184 }
2186 /* See if R is less than the lower bound or greater than the
2187 upper bound. */
2190 {
2194 {
2198 }
2199 }
2202 {
2205 {
2208 {
2212 }
2213 }
2214 }
2222 }
2224 /* A subroutine of fold_convert_const handling conversions of a
2225 FIXED_CST to an integer type. */
2227 static tree
2229 {
2230 tree t;
2234 /* Right shift FIXED_CST to temp by fbit. */
2238 {
2243 /* Left shift temp to temp_trunc by fbit. */
2248 }
2249 else
2250 {
2255 }
2257 /* If FIXED_CST is negative, we need to round the value toward 0.
2258 By checking if the fractional bits are not zero to add 1 to temp. */
2261 {
2262 double_int one;
2266 }
2268 /* Given a fixed-point constant, make new constant with new type,
2269 appropriately sign-extended or truncated. */
2277 }
2279 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2280 to another floating point type. */
2282 static tree
2284 {
2285 REAL_VALUE_TYPE value;
2286 tree t;
2293 }
2295 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2296 to a floating point type. */
2298 static tree
2300 {
2301 REAL_VALUE_TYPE value;
2302 tree t;
2311 }
2313 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2314 to another fixed-point type. */
2316 static tree
2318 {
2319 FIXED_VALUE_TYPE value;
2320 tree t;
2327 /* Propagate overflow flags. */
2329 {
2332 }
2336 }
2338 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2339 to a fixed-point type. */
2341 static tree
2343 {
2344 FIXED_VALUE_TYPE value;
2345 tree t;
2354 /* Propagate overflow flags. */
2356 {
2359 }
2363 }
2365 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2366 to a fixed-point type. */
2368 static tree
2370 {
2371 FIXED_VALUE_TYPE value;
2372 tree t;
2380 /* Propagate overflow flags. */
2382 {
2385 }
2389 }
2391 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2392 type TYPE. If no simplification can be done return NULL_TREE. */
2394 static tree
2396 {
2401 {
2408 }
2410 {
2417 }
2419 {
2426 }
2428 }
2430 /* Construct a vector of zero elements of vector type TYPE. */
2432 static tree
2434 {
2445 }
2447 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2449 bool
2451 {
2466 {
2485 }
2486 }
2488 /* Convert expression ARG to type TYPE. Used by the middle-end for
2489 simple conversions in preference to calling the front-end's convert. */
2491 tree
2493 {
2495 tree tem;
2509 {
2514 {
2518 }
2523 {
2526 }
2533 {
2537 }
2539 {
2543 }
2545 {
2549 }
2552 {
2570 }
2575 {
2579 }
2582 {
2596 }
2600 {
2610 {
2614 {
2618 }
2626 }
2630 }
2648 }
2649 }
2650 \f
2651 /* Return false if expr can be assumed not to be an lvalue, true
2652 otherwise. */
2654 static bool
2656 {
2657 /* We only need to wrap lvalue tree codes. */
2659 {
2694 /* Assume the worst for front-end tree codes. */
2698 }
2701 }
2703 /* Return an expr equal to X but certainly not valid as an lvalue. */
2705 tree
2707 {
2708 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2709 us. */
2716 }
2718 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2719 Zero means allow extended lvalues. */
2723 /* When pedantic, return an expr equal to X but certainly not valid as a
2724 pedantic lvalue. Otherwise, return X. */
2726 static tree
2728 {
2731 else
2733 }
2734 \f
2735 /* Given a tree comparison code, return the code that is the logical inverse
2736 of the given code. It is not safe to do this for floating-point
2737 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2738 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2740 enum tree_code
2742 {
2747 {
2778 }
2779 }
2781 /* Similar, but return the comparison that results if the operands are
2782 swapped. This is safe for floating-point. */
2784 enum tree_code
2786 {
2788 {
2814 }
2815 }
2818 /* Convert a comparison tree code from an enum tree_code representation
2819 into a compcode bit-based encoding. This function is the inverse of
2820 compcode_to_comparison. */
2822 static enum comparison_code
2824 {
2826 {
2857 }
2858 }
2860 /* Convert a compcode bit-based encoding of a comparison operator back
2861 to GCC's enum tree_code representation. This function is the
2862 inverse of comparison_to_compcode. */
2864 static enum tree_code
2866 {
2868 {
2899 }
2900 }
2902 /* Return a tree for the comparison which is the combination of
2903 doing the AND or OR (depending on CODE) of the two operations LCODE
2904 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2905 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2906 if this makes the transformation invalid. */
2908 tree
2912 {
2919 {
2930 }
2933 {
2934 /* Eliminate unordered comparisons, as well as LTGT and ORD
2935 which are not used unless the mode has NaNs. */
2941 }
2943 {
2944 /* Check that the original operation and the optimized ones will trap
2945 under the same condition. */
2956 /* In a short-circuited boolean expression the LHS might be
2957 such that the RHS, if evaluated, will never trap. For
2958 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2959 if neither x nor y is NaN. (This is a mixed blessing: for
2960 example, the expression above will never trap, hence
2961 optimizing it to x < y would be invalid). */
2966 /* If the comparison was short-circuited, and only the RHS
2967 trapped, we may now generate a spurious trap. */
2972 /* If we changed the conditions that cause a trap, we lose. */
2975 }
2981 else
2984 }
2986 /* Return nonzero if CODE is a tree code that represents a truth value. */
2988 static int
2990 {
2995 }
2996 \f
2997 /* Return nonzero if two operands (typically of the same tree node)
2998 are necessarily equal. If either argument has side-effects this
2999 function returns zero. FLAGS modifies behavior as follows:
3001 If OEP_ONLY_CONST is set, only return nonzero for constants.
3002 This function tests whether the operands are indistinguishable;
3003 it does not test whether they are equal using C's == operation.
3004 The distinction is important for IEEE floating point, because
3005 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3006 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3008 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3009 even though it may hold multiple values during a function.
3010 This is because a GCC tree node guarantees that nothing else is
3011 executed between the evaluation of its "operands" (which may often
3012 be evaluated in arbitrary order). Hence if the operands themselves
3013 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3014 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3015 unset means assuming isochronic (or instantaneous) tree equivalence.
3016 Unless comparing arbitrary expression trees, such as from different
3017 statements, this flag can usually be left unset.
3019 If OEP_PURE_SAME is set, then pure functions with identical arguments
3020 are considered the same. It is used when the caller has other ways
3021 to ensure that global memory is unchanged in between. */
3023 int
3025 {
3026 /* If either is ERROR_MARK, they aren't equal. */
3030 /* If both types don't have the same signedness, then we can't consider
3031 them equal. We must check this before the STRIP_NOPS calls
3032 because they may change the signedness of the arguments. */
3036 /* If both types don't have the same precision, then it is not safe
3037 to strip NOPs. */
3044 /* In case both args are comparisons but with different comparison
3045 code, try to swap the comparison operands of one arg to produce
3046 a match and compare that variant. */
3050 {
3058 }
3061 /* This is needed for conversions and for COMPONENT_REF.
3062 Might as well play it safe and always test this. */
3068 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3069 We don't care about side effects in that case because the SAVE_EXPR
3070 takes care of that for us. In all other cases, two expressions are
3071 equal if they have no side effects. If we have two identical
3072 expressions with side effects that should be treated the same due
3073 to the only side effects being identical SAVE_EXPR's, that will
3074 be detected in the recursive calls below. */
3080 /* Next handle constant cases, those for which we can return 1 even
3081 if ONLY_CONST is set. */
3084 {
3099 {
3100 /* If we do not distinguish between signed and unsigned zero,
3101 consider them equal. */
3104 }
3108 {
3114 {
3116 flags))
3120 }
3123 }
3127 flags)
3129 flags));
3142 }
3147 /* Define macros to test an operand from arg0 and arg1 for equality and a
3148 variant that allows null and views null as being different from any
3149 non-null value. In the latter case, if either is null, the both
3150 must be; otherwise, do the normal comparison. */
3151 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3152 TREE_OPERAND (arg1, N), flags)
3154 #define OP_SAME_WITH_NULL(N) \
3155 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3156 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3159 {
3161 /* Two conversions are equal only if signedness and modes match. */
3163 {
3173 }
3183 /* For commutative ops, allow the other order. */
3191 /* If either of the pointer (or reference) expressions we are
3192 dereferencing contain a side effect, these cannot be equal. */
3198 {
3208 /* Operands 2 and 3 may be null.
3209 Compare the array index by value if it is constant first as we
3210 may have different types but same value here. */
3219 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3220 may be NULL when we're called to compare MEM_EXPRs. */
3230 }
3234 {
3249 /* Otherwise take into account this is a commutative operation. */
3257 }
3261 {
3263 /* If the CALL_EXPRs call different functions, then they
3264 clearly can not be equal. */
3266 flags))
3269 {
3273 else
3277 }
3279 /* Now see if all the arguments are the same. */
3280 {
3291 /* If we get here and both argument lists are exhausted
3292 then the CALL_EXPRs are equal. */
3294 }
3297 }
3300 /* Consider __builtin_sqrt equal to sqrt. */
3308 }
3310 #undef OP_SAME
3311 #undef OP_SAME_WITH_NULL
3312 }
3313 \f
3314 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3315 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3317 When in doubt, return 0. */
3319 static int
3321 {
3333 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3334 and see if the inner values are the same. This removes any
3335 signedness comparison, which doesn't matter here. */
3342 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3343 actual comparison operand, ARG0.
3345 First throw away any conversions to wider types
3346 already present in the operands. */
3355 {
3358 /* Make sure shorter operand is extended the right way
3359 to match the longer operand. */
3365 }
3368 }
3369 \f
3370 /* See if ARG is an expression that is either a comparison or is performing
3371 arithmetic on comparisons. The comparisons must only be comparing
3372 two different values, which will be stored in *CVAL1 and *CVAL2; if
3373 they are nonzero it means that some operands have already been found.
3374 No variables may be used anywhere else in the expression except in the
3375 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3376 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3378 If this is true, return 1. Otherwise, return zero. */
3380 static int
3382 {
3386 /* We can handle some of the tcc_expression cases here. */
3396 {
3397 /* If we've already found a CVAL1 or CVAL2, this expression is
3398 two complex to handle. */
3404 }
3407 {
3430 /* First see if we can handle the first operand, then the second. For
3431 the second operand, we know *CVAL1 can't be zero. It must be that
3432 one side of the comparison is each of the values; test for the
3433 case where this isn't true by failing if the two operands
3434 are the same. */
3443 ;
3447 ;
3448 else
3452 ;
3456 ;
3457 else
3464 }
3465 }
3466 \f
3467 /* ARG is a tree that is known to contain just arithmetic operations and
3468 comparisons. Evaluate the operations in the tree substituting NEW0 for
3469 any occurrence of OLD0 as an operand of a comparison and likewise for
3470 NEW1 and OLD1. */
3472 static tree
3474 {
3479 /* We can handle some of the tcc_expression cases here. */
3487 {
3502 {
3519 }
3520 /* Fall through - ??? */
3523 {
3527 /* We need to check both for exact equality and tree equality. The
3528 former will be true if the operand has a side-effect. In that
3529 case, we know the operand occurred exactly once. */
3542 }
3546 }
3547 }
3548 \f
3549 /* Return a tree for the case when the result of an expression is RESULT
3550 converted to TYPE and OMITTED was previously an operand of the expression
3551 but is now not needed (e.g., we folded OMITTED * 0).
3553 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3554 the conversion of RESULT to TYPE. */
3556 tree
3558 {
3561 /* If the resulting operand is an empty statement, just return the omitted
3562 statement casted to void. */
3570 }
3572 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3574 static tree
3576 {
3579 /* If the resulting operand is an empty statement, just return the omitted
3580 statement casted to void. */
3588 }
3590 /* Return a tree for the case when the result of an expression is RESULT
3591 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3592 of the expression but are now not needed.
3594 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3595 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3596 evaluated before OMITTED2. Otherwise, if neither has side effects,
3597 just do the conversion of RESULT to TYPE. */
3599 tree
3601 {
3610 }
3612 \f
3613 /* Return a simplified tree node for the truth-negation of ARG. This
3614 never alters ARG itself. We assume that ARG is an operation that
3615 returns a truth value (0 or 1).
3617 FIXME: one would think we would fold the result, but it causes
3618 problems with the dominator optimizer. */
3620 tree
3622 {
3626 /* If this is a comparison, we can simply invert it, except for
3627 floating-point non-equality comparisons, in which case we just
3628 enclose a TRUTH_NOT_EXPR around what we have. */
3631 {
3634 && flag_trapping_math
3638 else
3639 {
3644 else
3647 }
3648 }
3651 {
3666 /* Here we can invert either operand. We invert the first operand
3667 unless the second operand is a TRUTH_NOT_EXPR in which case our
3668 result is the XOR of the first operand with the inside of the
3669 negation of the second operand. */
3674 else
3693 {
3696 /* A COND_EXPR may have a throw as one operand, which
3697 then has void type. Just leave void operands
3698 as they are. */
3704 }
3737 }
3740 }
3742 /* Return a simplified tree node for the truth-negation of ARG. This
3743 never alters ARG itself. We assume that ARG is an operation that
3744 returns a truth value (0 or 1).
3746 FIXME: one would think we would fold the result, but it causes
3747 problems with the dominator optimizer. */
3749 tree
3751 {
3752 tree tem;
3762 }
3764 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3765 operands are another bit-wise operation with a common input. If so,
3766 distribute the bit operations to save an operation and possibly two if
3767 constants are involved. For example, convert
3768 (A | B) & (A | C) into A | (B & C)
3769 Further simplification will occur if B and C are constants.
3771 If this optimization cannot be done, 0 will be returned. */
3773 static tree
3775 {
3776 tree common;
3786 {
3790 }
3792 {
3796 }
3798 {
3802 }
3804 {
3808 }
3809 else
3814 }
3816 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3817 with code CODE. This optimization is unsafe. */
3818 static tree
3820 {
3824 /* (A / C) +- (B / C) -> (A +- B) / C. */
3834 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3839 {
3851 }
3854 }
3855 \f
3856 /* Subroutine for fold_truthop: decode a field reference.
3858 If EXP is a comparison reference, we return the innermost reference.
3860 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3861 set to the starting bit number.
3863 If the innermost field can be completely contained in a mode-sized
3864 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3866 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3867 otherwise it is not changed.
3869 *PUNSIGNEDP is set to the signedness of the field.
3871 *PMASK is set to the mask used. This is either contained in a
3872 BIT_AND_EXPR or derived from the width of the field.
3874 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3876 Return 0 if this is not a component reference or is one that we can't
3877 do anything with. */
3879 static tree
3884 {
3888 tree unsigned_type;
3891 /* All the optimizations using this function assume integer fields.
3892 There are problems with FP fields since the type_for_size call
3893 below can fail for, e.g., XFmode. */
3897 /* We are interested in the bare arrangement of bits, so strip everything
3898 that doesn't affect the machine mode. However, record the type of the
3899 outermost expression if it may matter below. */
3907 {
3913 }
3922 /* If the number of bits in the reference is the same as the bitsize of
3923 the outer type, then the outer type gives the signedness. Otherwise
3924 (in case of a small bitfield) the signedness is unchanged. */
3928 /* Compute the mask to access the bitfield. */
3937 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3945 }
3947 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3948 represents the sign bit of EXP's type. If EXP represents a sign
3949 or zero extension, also test VAL against the unextended type.
3950 The return value is the (sub)expression whose sign bit is VAL,
3951 or NULL_TREE otherwise. */
3953 static tree
3955 {
3959 tree t;
3961 /* Tree EXP must have an integral type. */
3966 /* Tree VAL must be an integer constant. */
3973 {
3980 }
3981 else
3982 {
3989 }
3991 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
3992 treat VAL as if it were unsigned. */
3997 /* Handle extension from a narrower type. */
4003 }
4005 /* Subroutine for fold_truthop: determine if an operand is simple enough
4006 to be evaluated unconditionally. */
4008 static int
4010 {
4011 /* Strip any conversions that don't change the machine mode. */
4020 /* Don't regard global variables as simple. They may be
4021 allocated in ways unknown to the compiler (shared memory,
4022 #pragma weak, etc). */
4025 /* Loading a static variable is unduly expensive, but global
4026 registers aren't expensive. */
4028 }
4029 \f
4030 /* The following functions are subroutines to fold_range_test and allow it to
4031 try to change a logical combination of comparisons into a range test.
4033 For example, both
4034 X == 2 || X == 3 || X == 4 || X == 5
4035 and
4036 X >= 2 && X <= 5
4037 are converted to
4038 (unsigned) (X - 2) <= 3
4040 We describe each set of comparisons as being either inside or outside
4041 a range, using a variable named like IN_P, and then describe the
4042 range with a lower and upper bound. If one of the bounds is omitted,
4043 it represents either the highest or lowest value of the type.
4045 In the comments below, we represent a range by two numbers in brackets
4046 preceded by a "+" to designate being inside that range, or a "-" to
4047 designate being outside that range, so the condition can be inverted by
4048 flipping the prefix. An omitted bound is represented by a "-". For
4049 example, "- [-, 10]" means being outside the range starting at the lowest
4050 possible value and ending at 10, in other words, being greater than 10.
4051 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4052 always false.
4054 We set up things so that the missing bounds are handled in a consistent
4055 manner so neither a missing bound nor "true" and "false" need to be
4056 handled using a special case. */
4058 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4059 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4060 and UPPER1_P are nonzero if the respective argument is an upper bound
4061 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4062 must be specified for a comparison. ARG1 will be converted to ARG0's
4063 type if both are specified. */
4065 static tree
4068 {
4069 tree tem;
4073 /* If neither arg represents infinity, do the normal operation.
4074 Else, if not a comparison, return infinity. Else handle the special
4075 comparison rules. Note that most of the cases below won't occur, but
4076 are handled for consistency. */
4079 {
4084 }
4089 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4090 for neither. In real maths, we cannot assume open ended ranges are
4091 the same. But, this is computer arithmetic, where numbers are finite.
4092 We can therefore make the transformation of any unbounded range with
4093 the value Z, Z being greater than any representable number. This permits
4094 us to treat unbounded ranges as equal. */
4098 {
4119 }
4122 }
4123 \f
4124 /* Given EXP, a logical expression, set the range it is testing into
4125 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4126 actually being tested. *PLOW and *PHIGH will be made of the same
4127 type as the returned expression. If EXP is not a comparison, we
4128 will most likely not be returning a useful value and range. Set
4129 *STRICT_OVERFLOW_P to true if the return value is only valid
4130 because signed overflow is undefined; otherwise, do not change
4131 *STRICT_OVERFLOW_P. */
4133 static tree
4136 {
4143 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4144 and see if we can refine the range. Some of the cases below may not
4145 happen, but it doesn't seem worth worrying about this. We "continue"
4146 the outer loop when we've changed something; otherwise we "break"
4147 the switch, which will "break" the while. */
4153 {
4158 {
4170 }
4173 {
4180 /* We can only do something if the range is testing for zero
4181 and if the second operand is an integer constant. Note that
4182 saying something is "in" the range we make is done by
4183 complementing IN_P since it will set in the initial case of
4184 being not equal to zero; "out" is leaving it alone. */
4191 {
4212 }
4214 /* If this is an unsigned comparison, we also know that EXP is
4215 greater than or equal to zero. We base the range tests we make
4216 on that fact, so we record it here so we can parse existing
4217 range tests. We test arg0_type since often the return type
4218 of, e.g. EQ_EXPR, is boolean. */
4220 {
4224 NULL_TREE))
4229 /* If the high bound is missing, but we have a nonzero low
4230 bound, reverse the range so it goes from zero to the low bound
4231 minus 1. */
4233 {
4238 }
4239 }
4245 /* (-x) IN [a,b] -> x in [-b, -a] */
4257 /* ~ X -> -X - 1 */
4266 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4267 move a constant to the other side. */
4272 /* If EXP is signed, any overflow in the computation is undefined,
4273 so we don't worry about it so long as our computations on
4274 the bounds don't overflow. For unsigned, overflow is defined
4275 and this is exactly the right thing. */
4287 /* Check for an unsigned range which has wrapped around the maximum
4288 value thus making n_high < n_low, and normalize it. */
4290 {
4296 /* If the range is of the form +/- [ x+1, x ], we won't
4297 be able to normalize it. But then, it represents the
4298 whole range or the empty set, so make it
4299 +/- [ -, - ]. */
4303 else
4305 }
4306 else
4330 /* If we're converting arg0 from an unsigned type, to exp,
4331 a signed type, we will be doing the comparison as unsigned.
4332 The tests above have already verified that LOW and HIGH
4333 are both positive.
4335 So we have to ensure that we will handle large unsigned
4336 values the same way that the current signed bounds treat
4337 negative values. */
4340 {
4341 tree high_positive;
4342 tree equiv_type;
4343 /* For fixed-point modes, we need to pass the saturating flag
4344 as the 2nd parameter. */
4349 else
4353 /* A range without an upper bound is, naturally, unbounded.
4354 Since convert would have cropped a very large value, use
4355 the max value for the destination type. */
4356 high_positive
4363 high_positive),
4366 /* If the low bound is specified, "and" the range with the
4367 range for which the original unsigned value will be
4368 positive. */
4370 {
4374 integer_zero_node),
4375 high_positive))
4379 }
4380 else
4381 {
4382 /* Otherwise, "or" the range with the range of the input
4383 that will be interpreted as negative. */
4387 integer_zero_node),
4388 high_positive))
4392 }
4393 }
4401 }
4404 }
4406 /* If EXP is a constant, we can evaluate whether this is true or false. */
4408 {
4415 }
4419 }
4420 \f
4421 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4422 type, TYPE, return an expression to test if EXP is in (or out of, depending
4423 on IN_P) the range. Return 0 if the test couldn't be created. */
4425 static tree
4427 {
4429 tree value;
4431 #ifdef HAVE_canonicalize_funcptr_for_compare
4432 /* Disable this optimization for function pointer expressions
4433 on targets that require function pointer canonicalization. */
4438 #endif
4441 {
4447 }
4465 {
4467 {
4471 }
4473 }
4475 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4477 {
4479 HOST_WIDE_INT hi;
4484 {
4487 }
4488 else
4489 {
4492 }
4495 {
4497 {
4500 }
4503 }
4504 }
4506 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4507 This requires wrap-around arithmetics for the type of the expression. */
4509 {
4511 /* There is no requirement that LOW be within the range of ETYPE
4512 if the latter is a subtype. It must, however, be within the base
4513 type of ETYPE. So be sure we do the subtraction in that type. */
4526 }
4528 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4531 {
4534 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4535 for the type in question, as we rely on this here. */
4545 else
4547 }
4557 {
4559 {
4565 }
4567 }
4575 }
4576 \f
4577 /* Return the predecessor of VAL in its type, handling the infinite case. */
4579 static tree
4581 {
4587 else
4589 }
4591 /* Return the successor of VAL in its type, handling the infinite case. */
4593 static tree
4595 {
4601 else
4603 }
4605 /* Given two ranges, see if we can merge them into one. Return 1 if we
4606 can, 0 if we can't. Set the output range into the specified parameters. */
4608 static int
4611 {
4615 tree tem;
4625 /* Make range 0 be the range that starts first, or ends last if they
4626 start at the same value. Swap them if it isn't. */
4629 || (lowequal
4632 {
4636 }
4638 /* Now flag two cases, whether the ranges are disjoint or whether the
4639 second range is totally subsumed in the first. Note that the tests
4640 below are simplified by the ones above. */
4646 /* We now have four cases, depending on whether we are including or
4647 excluding the two ranges. */
4649 {
4650 /* If they don't overlap, the result is false. If the second range
4651 is a subset it is the result. Otherwise, the range is from the start
4652 of the second to the end of the first. */
4657 else
4659 }
4662 {
4663 /* If they don't overlap, the result is the first range. If they are
4664 equal, the result is false. If the second range is a subset of the
4665 first, and the ranges begin at the same place, we go from just after
4666 the end of the second range to the end of the first. If the second
4667 range is not a subset of the first, or if it is a subset and both
4668 ranges end at the same place, the range starts at the start of the
4669 first range and ends just before the second range.
4670 Otherwise, we can't describe this as a single range. */
4676 {
4681 {
4682 /* We are in the weird situation where high0 > high1 but
4683 high1 has no successor. Punt. */
4685 }
4686 }
4688 {
4693 {
4694 /* low0 < low1 but low1 has no predecessor. Punt. */
4696 }
4697 }
4698 else
4700 }
4703 {
4704 /* If they don't overlap, the result is the second range. If the second
4705 is a subset of the first, the result is false. Otherwise,
4706 the range starts just after the first range and ends at the
4707 end of the second. */
4712 else
4713 {
4718 {
4719 /* high1 > high0 but high0 has no successor. Punt. */
4721 }
4722 }
4723 }
4725 else
4726 {
4727 /* The case where we are excluding both ranges. Here the complex case
4728 is if they don't overlap. In that case, the only time we have a
4729 range is if they are adjacent. If the second is a subset of the
4730 first, the result is the first. Otherwise, the range to exclude
4731 starts at the beginning of the first range and ends at the end of the
4732 second. */
4734 {
4739 else
4740 {
4741 /* Canonicalize - [min, x] into - [-, x]. */
4744 {
4749 /* FALLTHROUGH */
4762 }
4764 /* Canonicalize - [x, max] into - [x, -]. */
4767 {
4772 /* FALLTHROUGH */
4787 }
4789 /* The ranges might be also adjacent between the maximum and
4790 minimum values of the given type. For
4791 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4792 return + [x + 1, y - 1]. */
4794 {
4801 }
4802 else
4804 }
4805 }
4808 else
4810 }
4814 }
4815 \f
4817 /* Subroutine of fold, looking inside expressions of the form
4818 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4819 of the COND_EXPR. This function is being used also to optimize
4820 A op B ? C : A, by reversing the comparison first.
4822 Return a folded expression whose code is not a COND_EXPR
4823 anymore, or NULL_TREE if no folding opportunity is found. */
4825 static tree
4827 {
4832 tree tem;
4837 /* If we have A op 0 ? A : -A, consider applying the following
4838 transformations:
4840 A == 0? A : -A same as -A
4841 A != 0? A : -A same as A
4842 A >= 0? A : -A same as abs (A)
4843 A > 0? A : -A same as abs (A)
4844 A <= 0? A : -A same as -abs (A)
4845 A < 0? A : -A same as -abs (A)
4847 None of these transformations work for modes with signed
4848 zeros. If A is +/-0, the first two transformations will
4849 change the sign of the result (from +0 to -0, or vice
4850 versa). The last four will fix the sign of the result,
4851 even though the original expressions could be positive or
4852 negative, depending on the sign of A.
4854 Note that all these transformations are correct if A is
4855 NaN, since the two alternatives (A and -A) are also NaNs. */
4862 /* In the case that A is of the form X-Y, '-A' (arg2) may
4863 have already been folded to Y-X, check for that. */
4871 {
4883 /* Fall through. */
4905 }
4907 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4908 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4909 both transformations are correct when A is NaN: A != 0
4910 is then true, and A == 0 is false. */
4914 {
4919 }
4921 /* Try some transformations of A op B ? A : B.
4923 A == B? A : B same as B
4924 A != B? A : B same as A
4925 A >= B? A : B same as max (A, B)
4926 A > B? A : B same as max (B, A)
4927 A <= B? A : B same as min (A, B)
4928 A < B? A : B same as min (B, A)
4930 As above, these transformations don't work in the presence
4931 of signed zeros. For example, if A and B are zeros of
4932 opposite sign, the first two transformations will change
4933 the sign of the result. In the last four, the original
4934 expressions give different results for (A=+0, B=-0) and
4935 (A=-0, B=+0), but the transformed expressions do not.
4937 The first two transformations are correct if either A or B
4938 is a NaN. In the first transformation, the condition will
4939 be false, and B will indeed be chosen. In the case of the
4940 second transformation, the condition A != B will be true,
4941 and A will be chosen.
4943 The conversions to max() and min() are not correct if B is
4944 a number and A is not. The conditions in the original
4945 expressions will be false, so all four give B. The min()
4946 and max() versions would give a NaN instead. */
4949 /* Avoid these transformations if the COND_EXPR may be used
4950 as an lvalue in the C++ front-end. PR c++/19199. */
4951 && (in_gimple_form
4956 {
4961 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4963 {
4967 }
4970 {
4979 /* In C++ a ?: expression can be an lvalue, so put the
4980 operand which will be used if they are equal first
4981 so that we can convert this back to the
4982 corresponding COND_EXPR. */
4984 {
4991 }
4998 {
5005 }
5018 }
5019 }
5021 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5022 we might still be able to simplify this. For example,
5023 if C1 is one less or one more than C2, this might have started
5024 out as a MIN or MAX and been transformed by this function.
5025 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5031 {
5033 /* We can replace A with C1 in this case. */
5038 /* If C1 is C2 + 1, this is min(A, C2). */
5040 OEP_ONLY_CONST)
5044 OEP_ONLY_CONST))
5046 type,
5048 arg2));
5052 /* If C1 is C2 - 1, this is min(A, C2). */
5054 OEP_ONLY_CONST)
5058 OEP_ONLY_CONST))
5060 type,
5062 arg2));
5066 /* If C1 is C2 - 1, this is max(A, C2). */
5068 OEP_ONLY_CONST)
5072 OEP_ONLY_CONST))
5074 type,
5076 arg2));
5080 /* If C1 is C2 + 1, this is max(A, C2). */
5082 OEP_ONLY_CONST)
5086 OEP_ONLY_CONST))
5088 type,
5090 arg2));
5096 }
5099 }
5102 \f
5103 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5104 #define LOGICAL_OP_NON_SHORT_CIRCUIT (BRANCH_COST >= 2)
5105 #endif
5107 /* EXP is some logical combination of boolean tests. See if we can
5108 merge it into some range test. Return the new tree if so. */
5110 static tree
5112 {
5120 tree tem;
5124 /* If this is an OR operation, invert both sides; we will invert
5125 again at the end. */
5129 /* If both expressions are the same, if we can merge the ranges, and we
5130 can build the range test, return it or it inverted. If one of the
5131 ranges is always true or always false, consider it to be the same
5132 expression as the other. */
5140 {
5144 }
5146 /* On machines where the branch cost is expensive, if this is a
5147 short-circuited branch and the underlying object on both sides
5148 is the same, make a non-short-circuit operation. */
5154 {
5155 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5156 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5157 which cases we can't do this. */
5165 {
5174 {
5177 WARN_STRICT_OVERFLOW_COMPARISON);
5181 }
5182 }
5183 }
5186 }
5187 \f
5188 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5189 bit value. Arrange things so the extra bits will be set to zero if and
5190 only if C is signed-extended to its full width. If MASK is nonzero,
5191 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5193 static tree
5195 {
5198 tree temp;
5203 /* We work by getting just the sign bit into the low-order bit, then
5204 into the high-order bit, then sign-extend. We then XOR that value
5205 with C. */
5209 /* We must use a signed type in order to get an arithmetic right shift.
5210 However, we must also avoid introducing accidental overflows, so that
5211 a subsequent call to integer_zerop will work. Hence we must
5212 do the type conversion here. At this point, the constant is either
5213 zero or one, and the conversion to a signed type can never overflow.
5214 We could get an overflow if this conversion is done anywhere else. */
5223 /* If necessary, convert the type back to match the type of C. */
5228 }
5229 \f
5230 /* Find ways of folding logical expressions of LHS and RHS:
5231 Try to merge two comparisons to the same innermost item.
5232 Look for range tests like "ch >= '0' && ch <= '9'".
5233 Look for combinations of simple terms on machines with expensive branches
5234 and evaluate the RHS unconditionally.
5236 For example, if we have p->a == 2 && p->b == 4 and we can make an
5237 object large enough to span both A and B, we can do this with a comparison
5238 against the object ANDed with the a mask.
5240 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5241 operations to do this with one comparison.
5243 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5244 function and the one above.
5246 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5247 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5249 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5250 two operands.
5252 We return the simplified tree or 0 if no optimization is possible. */
5254 static tree
5256 {
5257 /* If this is the "or" of two comparisons, we can do something if
5258 the comparisons are NE_EXPR. If this is the "and", we can do something
5259 if the comparisons are EQ_EXPR. I.e.,
5260 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5262 WANTED_CODE is this operation code. For single bit fields, we can
5263 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5264 comparison for one-bit fields. */
5286 /* Start by getting the comparison codes. Fail if anything is volatile.
5287 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5288 it were surrounded with a NE_EXPR. */
5297 {
5301 }
5304 {
5308 }
5319 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5322 {
5323 tree result;
5326 {
5331 }
5334 {
5340 }
5341 }
5346 /* If the RHS can be evaluated unconditionally and its operands are
5347 simple, it wins to evaluate the RHS unconditionally on machines
5348 with expensive branches. In this case, this isn't a comparison
5349 that can be merged. Avoid doing this if the RHS is a floating-point
5350 comparison since those can trap. */
5356 {
5357 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5368 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5380 {
5384 }
5385 }
5387 /* See if the comparisons can be merged. Then get all the parameters for
5388 each side. */
5412 /* It must be true that the inner operation on the lhs of each
5413 comparison must be the same if we are to be able to do anything.
5414 Then see if we have constants. If not, the same must be true for
5415 the rhs's. */
5426 else
5429 /* If either comparison code is not correct for our logical operation,
5430 fail. However, we can convert a one-bit comparison against zero into
5431 the opposite comparison against that bit being set in the field. */
5435 {
5437 {
5438 /* Make the left operand unsigned, since we are only interested
5439 in the value of one bit. Otherwise we are doing the wrong
5440 thing below. */
5443 }
5444 else
5446 }
5448 /* This is analogous to the code for l_const above. */
5450 {
5452 {
5455 }
5456 else
5458 }
5460 /* See if we can find a mode that contains both fields being compared on
5461 the left. If we can't, fail. Otherwise, update all constants and masks
5462 to be relative to a field of that size. */
5467 volatilep);
5477 {
5480 }
5488 {
5496 {
5500 }
5501 }
5503 {
5511 {
5515 }
5516 }
5518 /* Handle the case of comparisons with constants. If there is something in
5519 common between the masks, those bits of the constants must be the same.
5520 If not, the condition is always false. Test for this to avoid generating
5521 incorrect code below. */
5526 {
5528 {
5531 }
5532 else
5533 {
5536 }
5537 }
5540 }
5541 \f
5542 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5543 constant. */
5545 static tree
5547 {
5550 tree comp_const;
5551 tree minmax_const;
5553 tree inner;
5564 /* If something does not permit us to optimize, return the original tree. */
5572 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5573 and GT_EXPR, doing the rest with recursive calls using logical
5574 simplifications. */
5576 {
5578 {
5584 }
5587 return
5589 optimize_minmax_comparison
5591 optimize_minmax_comparison
5596 /* MAX (X, 0) == 0 -> X <= 0 */
5600 /* MAX (X, 0) == 5 -> X == 5 */
5604 /* MAX (X, 0) == -1 -> false */
5608 /* MIN (X, 0) == 0 -> X >= 0 */
5612 /* MIN (X, 0) == 5 -> false */
5615 else
5616 /* MIN (X, 0) == -1 -> X == -1 */
5621 /* MAX (X, 0) > 0 -> X > 0
5622 MAX (X, 0) > 5 -> X > 5 */
5626 /* MAX (X, 0) > -1 -> true */
5630 /* MIN (X, 0) > 0 -> false
5631 MIN (X, 0) > 5 -> false */
5634 else
5635 /* MIN (X, 0) > -1 -> X > -1 */
5640 }
5641 }
5642 \f
5643 /* T is an integer expression that is being multiplied, divided, or taken a
5644 modulus (CODE says which and what kind of divide or modulus) by a
5645 constant C. See if we can eliminate that operation by folding it with
5646 other operations already in T. WIDE_TYPE, if non-null, is a type that
5647 should be used for the computation if wider than our type.
5649 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5650 (X * 2) + (Y * 4). We must, however, be assured that either the original
5651 expression would not overflow or that overflow is undefined for the type
5652 in the language in question.
5654 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5655 the machine has a multiply-accumulate insn or that this is part of an
5656 addressing calculation.
5658 If we return a non-null expression, it is an equivalent form of the
5659 original computation, but need not be in the original type.
5661 We set *STRICT_OVERFLOW_P to true if the return values depends on
5662 signed overflow being undefined. Otherwise we do not change
5663 *STRICT_OVERFLOW_P. */
5665 static tree
5668 {
5669 /* To avoid exponential search depth, refuse to allow recursion past
5670 three levels. Beyond that (1) it's highly unlikely that we'll find
5671 something interesting and (2) we've probably processed it before
5672 when we built the inner expression. */
5675 tree ret;
5680 depth++;
5682 depth--;
5685 }
5687 static tree
5690 {
5701 /* Don't deal with constants of zero here; they confuse the code below. */
5711 /* Note that we need not handle conditional operations here since fold
5712 already handles those cases. So just do arithmetic here. */
5714 {
5716 /* For a constant, we can always simplify if we are a multiply
5717 or (for divide and modulus) if it is a multiple of our constant. */
5725 /* If op0 is an expression ... */
5731 /* ... and is unsigned, and its type is smaller than ctype,
5732 then we cannot pass through as widening. */
5738 /* ... or this is a truncation (t is narrower than op0),
5739 then we cannot pass through this narrowing. */
5742 /* ... or signedness changes for division or modulus,
5743 then we cannot pass through this conversion. */
5747 /* ... or has undefined overflow while the converted to
5748 type has not, we cannot do the operation in the inner type
5749 as that would introduce undefined overflow. */
5754 /* Pass the constant down and see if we can make a simplification. If
5755 we can, replace this expression with the inner simplification for
5756 possible later conversion to our or some other type. */
5761 code == MULT_EXPR
5763 strict_overflow_p))))
5768 /* If widening the type changes it from signed to unsigned, then we
5769 must avoid building ABS_EXPR itself as unsigned. */
5771 {
5775 {
5778 }
5780 }
5781 /* If the constant is negative, we cannot simplify this. */
5784 /* FALLTHROUGH */
5792 /* If widening the type changes the signedness, then we can't perform
5793 this optimization as that changes the result. */
5797 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5803 {
5810 }
5814 /* If the second operand is constant, this is a multiplication
5815 or floor division, by a power of two, so we can treat it that
5816 way unless the multiplier or divisor overflows. Signed
5817 left-shift overflow is implementation-defined rather than
5818 undefined in C90, so do not convert signed left shift into
5819 multiplication. */
5822 /* const_binop may not detect overflow correctly,
5823 so check for it explicitly here. */
5828 size_one_node,
5838 /* See if we can eliminate the operation on both sides. If we can, we
5839 can return a new PLUS or MINUS. If we can't, the only remaining
5840 cases where we can do anything are if the second operand is a
5841 constant. */
5847 /* If not multiplication, we can only do this if both operands
5848 are divisible by c. */
5851 {
5856 }
5858 /* If this was a subtraction, negate OP1 and set it to be an addition.
5859 This simplifies the logic below. */
5866 /* If either OP1 or C are negative, this optimization is not safe for
5867 some of the division and remainder types while for others we need
5868 to change the code. */
5870 {
5878 }
5880 /* If it's a multiply or a division/modulus operation of a multiple
5881 of our constant, do the operation and verify it doesn't overflow. */
5884 {
5887 /* We allow the constant to overflow with wrapping semantics. */
5891 }
5892 else
5895 /* If we have an unsigned type is not a sizetype, we cannot widen
5896 the operation since it will change the result if the original
5897 computation overflowed. */
5903 /* If we were able to eliminate our operation from the first side,
5904 apply our operation to the second side and reform the PLUS. */
5908 /* The last case is if we are a multiply. In that case, we can
5909 apply the distributive law to commute the multiply and addition
5910 if the multiplication of the constants doesn't overflow. */
5916 op1);
5921 /* We have a special case here if we are doing something like
5922 (C * 8) % 4 since we know that's zero. */
5929 /* ... fall through ... */
5933 /* If we can extract our operation from the LHS, do so and return a
5934 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5935 do something only if the second operand is a constant. */
5949 /* If these are the same operation types, we can associate them
5950 assuming no overflow. */
5957 /* If these operations "cancel" each other, we have the main
5958 optimizations of this pass, which occur when either constant is a
5959 multiple of the other, in which case we replace this with either an
5960 operation or CODE or TCODE.
5962 If we have an unsigned type that is not a sizetype, we cannot do
5963 this since it will change the result if the original computation
5964 overflowed. */
5972 {
5974 {
5981 }
5983 {
5990 }
5991 }
5996 }
5999 }
6000 \f
6001 /* Return a node which has the indicated constant VALUE (either 0 or
6002 1), and is of the indicated TYPE. */
6004 tree
6006 {
6011 else
6013 }
6016 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6017 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6018 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6019 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6020 COND is the first argument to CODE; otherwise (as in the example
6021 given here), it is the second argument. TYPE is the type of the
6022 original expression. Return NULL_TREE if no simplification is
6023 possible. */
6025 static tree
6029 {
6036 /* This transformation is only worthwhile if we don't have to wrap
6037 arg in a SAVE_EXPR, and the operation can be simplified on at least
6038 one of the branches once its pushed inside the COND_EXPR. */
6043 {
6047 /* If this operand throws an expression, then it does not make
6048 sense to try to perform a logical or arithmetic operation
6049 involving it. */
6054 }
6055 else
6056 {
6061 }
6065 {
6069 else
6071 }
6073 {
6077 else
6079 }
6083 }
6085 \f
6086 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6088 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6089 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6090 ADDEND is the same as X.
6092 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6093 and finite. The problematic cases are when X is zero, and its mode
6094 has signed zeros. In the case of rounding towards -infinity,
6095 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6096 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6098 bool
6100 {
6104 /* Don't allow the fold with -fsignaling-nans. */
6108 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6112 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6117 /* The mode has signed zeros, and we have to honor their sign.
6118 In this situation, there is only one case we can return true for.
6119 X - 0 is the same as X unless rounding towards -infinity is
6120 supported. */
6122 }
6124 /* Subroutine of fold() that checks comparisons of built-in math
6125 functions against real constants.
6127 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6128 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6129 is the type of the result and ARG0 and ARG1 are the operands of the
6130 comparison. ARG1 must be a TREE_REAL_CST.
6132 The function returns the constant folded tree if a simplification
6133 can be made, and NULL_TREE otherwise. */
6135 static tree
6138 {
6139 REAL_VALUE_TYPE c;
6142 {
6148 {
6149 /* sqrt(x) < y is always false, if y is negative. */
6153 /* sqrt(x) > y is always true, if y is negative and we
6154 don't care about NaNs, i.e. negative values of x. */
6158 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6161 }
6163 {
6164 REAL_VALUE_TYPE c2;
6170 {
6171 /* sqrt(x) > y is x == +Inf, when y is very large. */
6176 /* sqrt(x) > y is always false, when y is very large
6177 and we don't care about infinities. */
6179 }
6181 /* sqrt(x) > c is the same as x > c*c. */
6184 }
6186 {
6187 REAL_VALUE_TYPE c2;
6193 {
6194 /* sqrt(x) < y is always true, when y is a very large
6195 value and we don't care about NaNs or Infinities. */
6199 /* sqrt(x) < y is x != +Inf when y is very large and we
6200 don't care about NaNs. */
6205 /* sqrt(x) < y is x >= 0 when y is very large and we
6206 don't care about Infinities. */
6211 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6220 dconst0)),
6223 c2)));
6224 }
6226 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6231 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6234 {
6239 dconst0)),
6242 c2)));
6243 }
6244 }
6245 }
6248 }
6250 /* Subroutine of fold() that optimizes comparisons against Infinities,
6251 either +Inf or -Inf.
6253 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6254 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6255 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6257 The function returns the constant folded tree if a simplification
6258 can be made, and NULL_TREE otherwise. */
6260 static tree
6262 {
6264 REAL_VALUE_TYPE max;
6265 tree temp;
6270 /* For negative infinity swap the sense of the comparison. */
6276 {
6278 /* x > +Inf is always false, if with ignore sNANs. */
6284 /* x <= +Inf is always true, if we don't case about NaNs. */
6288 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6291 {
6294 }
6299 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6305 /* x < +Inf is always equal to x <= DBL_MAX. */
6311 /* x != +Inf is always equal to !(x > DBL_MAX). */
6323 }
6326 }
6328 /* Subroutine of fold() that optimizes comparisons of a division by
6329 a nonzero integer constant against an integer constant, i.e.
6330 X/C1 op C2.
6332 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6333 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6334 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6336 The function returns the constant folded tree if a simplification
6337 can be made, and NULL_TREE otherwise. */
6339 static tree
6341 {
6346 HOST_WIDE_INT hpart;
6351 /* We have to do this the hard way to detect unsigned overflow.
6352 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6363 {
6368 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6376 }
6378 {
6382 {
6401 }
6402 }
6403 else
6404 {
6405 /* A negative divisor reverses the relational operators. */
6411 {
6430 }
6431 }
6434 {
6455 {
6458 }
6463 {
6466 }
6471 {
6474 }
6479 {
6482 }
6487 }
6490 }
6493 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6494 equality/inequality test, then return a simplified form of the test
6495 using a sign testing. Otherwise return NULL. TYPE is the desired
6496 result type. */
6498 static tree
6500 tree result_type)
6501 {
6502 /* If this is testing a single bit, we can optimize the test. */
6506 {
6507 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6508 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6512 /* This is only a win if casting to a signed type is cheap,
6513 i.e. when arg00's type is not a partial mode. */
6516 {
6521 }
6522 }
6525 }
6527 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6528 equality/inequality test, then return a simplified form of
6529 the test using shifts and logical operations. Otherwise return
6530 NULL. TYPE is the desired result type. */
6532 tree
6534 tree result_type)
6535 {
6536 /* If this is testing a single bit, we can optimize the test. */
6540 {
6549 /* First, see if we can fold the single bit test into a sign-bit
6550 test. */
6552 result_type);
6556 /* Otherwise we have (A & C) != 0 where C is a single bit,
6557 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6558 Similarly for (A & C) == 0. */
6560 /* If INNER is a right shift of a constant and it plus BITNUM does
6561 not overflow, adjust BITNUM and INNER. */
6568 {
6571 }
6573 /* If we are going to be able to omit the AND below, we must do our
6574 operations as unsigned. If we must use the AND, we have a choice.
6575 Normally unsigned is faster, but for some machines signed is. */
6576 #ifdef LOAD_EXTEND_OP
6579 #else
6581 #endif
6597 /* Put the AND last so it can combine with more things. */
6600 /* Make sure to return the proper type. */
6604 }
6606 }
6608 /* Check whether we are allowed to reorder operands arg0 and arg1,
6609 such that the evaluation of arg1 occurs before arg0. */
6611 static bool
6613 {
6620 }
6622 /* Test whether it is preferable two swap two operands, ARG0 and
6623 ARG1, for example because ARG0 is an integer constant and ARG1
6624 isn't. If REORDER is true, only recommend swapping if we can
6625 evaluate the operands in reverse order. */
6627 bool
6629 {
6665 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6666 for commutative and comparison operators. Ensuring a canonical
6667 form allows the optimizers to find additional redundancies without
6668 having to explicitly check for both orderings. */
6674 /* Put SSA_NAMEs last. */
6680 /* Put variables last. */
6687 }
6689 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6690 ARG0 is extended to a wider type. */
6692 static tree
6694 {
6696 tree arg1_unw;
6705 #ifdef HAVE_canonicalize_funcptr_for_compare
6706 /* Disable this optimization if we're casting a function pointer
6707 type on targets that require function pointer canonicalization. */
6712 #endif
6719 /* If possible, express the comparison in the shorter mode. */
6737 /* If we are comparing with the integer that does not fit into the range
6738 of the shorter type, the result is known. */
6749 {
6776 }
6779 }
6781 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6782 ARG0 just the signedness is changed. */
6784 static tree
6787 {
6788 tree arg0_inner;
6799 #ifdef HAVE_canonicalize_funcptr_for_compare
6800 /* Disable this optimization if we're casting a function pointer
6801 type on targets that require function pointer canonicalization. */
6806 #endif
6811 /* If the conversion is from an integral subtype to its basetype
6812 leave it alone. */
6831 else
6835 }
6837 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6838 step of the array. Reconstructs s and delta in the case of s * delta
6839 being an integer constant (and thus already folded).
6840 ADDR is the address. MULT is the multiplicative expression.
6841 If the function succeeds, the new address expression is returned. Otherwise
6842 NULL_TREE is returned. */
6844 static tree
6846 {
6850 tree itype;
6853 /* Strip the nops that might be added when converting op1 to sizetype. */
6856 /* Canonicalize op1 into a possibly non-constant delta
6857 and an INTEGER_CST s. */
6859 {
6866 {
6869 }
6871 {
6874 }
6875 else
6877 }
6879 {
6882 }
6883 else
6884 {
6885 /* Simulate we are delta * 1. */
6888 }
6891 {
6893 {
6894 /* Remember if this was a multi-dimensional array. */
6907 {
6910 }
6911 else
6912 {
6913 /* Try if delta is a multiple of step. */
6918 }
6920 /* Only fold here if we can verify we do not overflow one
6921 dimension of a multi-dimensional array. */
6923 {
6924 tree tmp;
6940 }
6943 }
6944 else
6949 }
6951 /* We found the suitable array reference. So copy everything up to it,
6952 and replace the index. */
6959 {
6963 }
6971 }
6974 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6975 means A >= Y && A != MAX, but in this case we know that
6976 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6978 static tree
6980 {
6987 else
6996 {
6999 }
7001 {
7004 }
7005 else
7012 {
7013 /* Convert the pointer types into integer before taking the difference. */
7017 }
7018 else
7025 }
7027 /* Fold a sum or difference of at least one multiplication.
7028 Returns the folded tree or NULL if no simplification could be made. */
7030 static tree
7032 {
7036 /* (A * C) +- (B * C) -> (A+-B) * C.
7037 (A * C) +- A -> A * (C+-1).
7038 We are most concerned about the case where C is a constant,
7039 but other combinations show up during loop reduction. Since
7040 it is not difficult, try all four possibilities. */
7043 {
7046 }
7048 {
7051 }
7052 else
7053 {
7054 /* We cannot generate constant 1 for fract. */
7059 }
7061 {
7064 }
7066 {
7069 }
7070 else
7071 {
7072 /* We cannot generate constant 1 for fract. */
7077 }
7089 /* No identical multiplicands; see if we can find a common
7090 power-of-two factor in non-power-of-two multiplies. This
7091 can help in multi-dimensional array access. */
7094 {
7097 tree maybe_same;
7101 /* Move min of absolute values to int11. */
7104 {
7109 }
7110 else
7114 {
7122 }
7123 }
7133 }
7135 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7136 specified by EXPR into the buffer PTR of length LEN bytes.
7137 Return the number of bytes placed in the buffer, or zero
7138 upon failure. */
7140 static int
7142 {
7153 {
7157 else
7162 {
7169 else
7171 }
7172 else
7175 }
7177 }
7180 /* Subroutine of native_encode_expr. Encode the REAL_CST
7181 specified by EXPR into the buffer PTR of length LEN bytes.
7182 Return the number of bytes placed in the buffer, or zero
7183 upon failure. */
7185 static int
7187 {
7193 /* There are always 32 bits in each long, no matter the size of
7194 the hosts long. We handle floating point representations with
7195 up to 192 bits. */
7206 {
7211 {
7218 else
7220 }
7221 else
7224 }
7226 }
7228 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7229 specified by EXPR into the buffer PTR of length LEN bytes.
7230 Return the number of bytes placed in the buffer, or zero
7231 upon failure. */
7233 static int
7235 {
7237 tree part;
7248 }
7251 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7252 specified by EXPR into the buffer PTR of length LEN bytes.
7253 Return the number of bytes placed in the buffer, or zero
7254 upon failure. */
7256 static int
7258 {
7268 {
7270 {
7273 }
7274 else
7278 {
7281 }
7282 else
7283 {
7287 }
7289 }
7291 }
7294 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7295 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7296 buffer PTR of length LEN bytes. Return the number of bytes
7297 placed in the buffer, or zero upon failure. */
7299 int
7301 {
7303 {
7318 }
7319 }
7322 /* Subroutine of native_interpret_expr. Interpret the contents of
7323 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7324 If the buffer cannot be interpreted, return NULL_TREE. */
7326 static tree
7328 {
7342 {
7345 {
7352 else
7354 }
7355 else
7361 else
7364 }
7367 }
7370 /* Subroutine of native_interpret_expr. Interpret the contents of
7371 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7372 If the buffer cannot be interpreted, return NULL_TREE. */
7374 static tree
7376 {
7381 /* There are always 32 bits in each long, no matter the size of
7382 the hosts long. We handle floating point representations with
7383 up to 192 bits. */
7384 REAL_VALUE_TYPE r;
7395 {
7398 {
7405 else
7407 }
7408 else
7413 }
7417 }
7420 /* Subroutine of native_interpret_expr. Interpret the contents of
7421 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7422 If the buffer cannot be interpreted, return NULL_TREE. */
7424 static tree
7426 {
7441 }
7444 /* Subroutine of native_interpret_expr. Interpret the contents of
7445 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7446 If the buffer cannot be interpreted, return NULL_TREE. */
7448 static tree
7450 {
7462 {
7467 }
7469 }
7472 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7473 the buffer PTR of length LEN as a constant of type TYPE. For
7474 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7475 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7476 return NULL_TREE. */
7478 tree
7480 {
7482 {
7499 }
7500 }
7503 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7504 TYPE at compile-time. If we're unable to perform the conversion
7505 return NULL_TREE. */
7507 static tree
7509 {
7510 /* We support up to 512-bit values (for V8DFmode). */
7514 /* Check that the host and target are sane. */
7523 }
7525 /* Build an expression for the address of T. Folds away INDIRECT_REF
7526 to avoid confusing the gimplify process. When IN_FOLD is true
7527 avoid modifications of T. */
7529 static tree
7531 {
7532 /* The size of the object is not relevant when talking about its address. */
7536 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7539 {
7544 }
7546 {
7556 }
7557 else
7561 }
7563 /* Build an expression for the address of T with type PTRTYPE. This
7564 function modifies the input parameter 'T' by sometimes setting the
7565 TREE_ADDRESSABLE flag. */
7567 tree
7569 {
7571 }
7573 /* Build an expression for the address of T. This function modifies
7574 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7575 flag. When called from fold functions, use fold_addr_expr instead. */
7577 tree
7579 {
7583 }
7585 /* Same as build_fold_addr_expr, builds an expression for the address
7586 of T, but avoids touching the input node 't'. Fold functions
7587 should use this version. */
7589 static tree
7591 {
7595 }
7597 /* Fold a unary expression of code CODE and type TYPE with operand
7598 OP0. Return the folded expression if folding is successful.
7599 Otherwise, return NULL_TREE. */
7601 tree
7603 {
7604 tree tem;
7605 tree arg0;
7613 {
7616 {
7617 /* Don't use STRIP_NOPS, because signedness of argument type
7618 matters. */
7620 }
7621 else
7622 {
7623 /* Strip any conversions that don't change the mode. This
7624 is safe for every expression, except for a comparison
7625 expression because its signedness is derived from its
7626 operands.
7628 Note that this is done as an internal manipulation within
7629 the constant folder, in order to find the simplest
7630 representation of the arguments so that their form can be
7631 studied. In any cases, the appropriate type conversions
7632 should be put back in the tree that will get out of the
7633 constant folder. */
7635 }
7636 }
7639 {
7644 {
7654 /* If this was a conversion, and all we did was to move into
7655 inside the COND_EXPR, bring it back out. But leave it if
7656 it is a conversion from integer to integer and the
7657 result precision is no wider than a word since such a
7658 conversion is cheap and may be optimized away by combine,
7659 while it couldn't if it were outside the COND_EXPR. Then return
7660 so we don't get into an infinite recursion loop taking the
7661 conversion out and then back in. */
7673 && (INTEGRAL_TYPE_P
7685 }
7687 {
7689 {
7693 }
7697 integer_one_node),
7699 integer_zero_node));
7700 }
7701 }
7704 {
7706 /* Re-association barriers around constants and other re-association
7707 barriers can be removed. */
7720 /* If we have (type) (a CMP b) and type is an integral type, return
7721 new expression involving the new type. */
7726 /* Handle cases of two conversions in a row. */
7729 {
7751 /* In addition to the cases of two conversions in a row
7752 handled below, if we are converting something to its own
7753 type via an object of identical or wider precision, neither
7754 conversion is needed. */
7761 /* Likewise, if the intermediate and final types are either both
7762 float or both integer, we don't need the middle conversion if
7763 it is wider than the final type and doesn't change the signedness
7764 (for integers). Avoid this if the final type is a pointer
7765 since then we sometimes need the inner conversion. Likewise if
7766 the outer has a precision not equal to the size of its mode. */
7775 && ! final_ptr
7779 /* If we have a sign-extension of a zero-extended value, we can
7780 replace that by a single zero-extension. */
7786 /* Two conversions in a row are not needed unless:
7787 - some conversion is floating-point (overstrict for now), or
7788 - some conversion is a vector (overstrict for now), or
7789 - the intermediate type is narrower than both initial and
7790 final, or
7791 - the intermediate type and innermost type differ in signedness,
7792 and the outermost type is wider than the intermediate, or
7793 - the initial type is a pointer type and the precisions of the
7794 intermediate and final types differ, or
7795 - the final type is a pointer type and the precisions of the
7796 initial and intermediate types differ. */
7810 }
7812 /* Handle (T *)&A.B.C for A being of type T and B and C
7813 living at offset zero. This occurs frequently in
7814 C++ upcasting and then accessing the base. */
7818 {
7820 tree offset;
7826 /* If the reference was to a (constant) zero offset, we can use
7827 the address of the base if it has the same base type
7828 as the result type. */
7833 }
7838 /* Detect assigning a bitfield. */
7840 && DECL_BIT_FIELD
7842 {
7843 /* Don't leave an assignment inside a conversion
7844 unless assigning a bitfield. */
7846 /* First do the assignment, then return converted constant. */
7851 }
7853 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7854 constants (if x has signed type, the sign bit cannot be set
7855 in c). This folds extension into the BIT_AND_EXPR. */
7860 {
7870 <= HOST_BITS_PER_WIDE_INT
7872 {
7879 #ifdef LOAD_EXTEND_OP
7881 && !flag_syntax_only
7884 {
7888 }
7889 #endif
7890 }
7892 {
7898 }
7899 }
7901 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7902 when one of the new casts will fold away. Conservatively we assume
7903 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7909 {
7915 }
7917 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7918 of the same precision, and X is an integer type not narrower than
7919 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7926 {
7931 }
7933 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7934 type of X and Y (integer types only). */
7939 {
7940 /* Be careful not to introduce new overflows. */
7941 tree mult_type;
7944 else
7951 }
7966 /* For integral conversions with the same precision or pointer
7967 conversions use a NOP_EXPR instead. */
7973 /* Do not muck with VIEW_CONVERT_EXPRs that convert from
7974 a sub-type to its base type as generated by the Ada FE. */
7979 /* Strip inner integral conversions that do not change the precision. */
8003 /* Convert fabs((double)float) into (double)fabsf(float). */
8006 {
8011 targ0));
8012 }
8013 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8019 /* Strip sign ops from argument. */
8021 {
8025 }
8032 {
8037 }
8039 {
8044 }
8054 /* Convert ~ (-A) to A - 1. */
8059 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8067 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8080 /* Perform BIT_NOT_EXPR on each element individually. */
8082 {
8087 {
8089 {
8095 }
8096 else
8099 }
8102 }
8107 /* The argument to invert_truthvalue must have Boolean type. */
8111 /* Note that the operand of this must be an int
8112 and its values must be 0 or 1.
8113 ("true" is a fixed value perhaps depending on the language,
8114 but we don't handle values other than 1 correctly yet.) */
8129 {
8137 }
8139 {
8143 }
8145 {
8149 {
8158 }
8159 }
8171 {
8179 }
8181 {
8185 }
8187 {
8191 {
8200 }
8201 }
8207 }
8209 /* Fold a binary expression of code CODE and type TYPE with operands
8210 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8211 Return the folded expression if folding is successful. Otherwise,
8212 return NULL_TREE. */
8214 static tree
8216 {
8223 else
8226 /* MIN (MAX (a, b), b) == b. */
8231 /* MIN (MAX (b, a), b) == b. */
8237 /* MIN (a, MAX (a, b)) == a. */
8243 /* MIN (a, MAX (b, a)) == a. */
8250 }
8252 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8253 by changing CODE to reduce the magnitude of constants involved in
8254 ARG0 of the comparison.
8255 Returns a canonicalized comparison tree if a simplification was
8256 possible, otherwise returns NULL_TREE.
8257 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8258 valid if signed overflow is undefined. */
8260 static tree
8264 {
8270 /* Match A +- CST code arg1 and CST code arg1. */
8277 /* Identify the constant in arg0 and its sign. */
8280 else
8284 /* Overflowed constants and zero will cause problems. */
8289 /* See if we can reduce the magnitude of the constant in
8290 arg0 by changing the comparison code. */
8292 {
8293 /* CST <= arg1 -> CST-1 < arg1. */
8296 /* -CST < arg1 -> -CST-1 <= arg1. */
8299 /* CST > arg1 -> CST-1 >= arg1. */
8302 /* -CST >= arg1 -> -CST-1 > arg1. */
8305 else
8307 /* arg1 code' CST' might be more canonical. */
8309 }
8310 else
8311 {
8312 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8316 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8320 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8324 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8328 else
8331 }
8333 /* Now build the constant reduced in magnitude. */
8339 /* If swapping might yield to a more canonical form, do so. */
8342 else
8344 }
8346 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8347 overflow further. Try to decrease the magnitude of constants involved
8348 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8349 and put sole constants at the second argument position.
8350 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8352 static tree
8355 {
8356 tree t;
8361 /* In principle pointers also have undefined overflow behavior,
8362 but that causes problems elsewhere. */
8367 /* Try canonicalization by simplifying arg0. */
8372 {
8376 }
8378 /* Try canonicalization by simplifying arg1 using the swapped
8379 comparison. */
8387 }
8389 /* Subroutine of fold_binary. This routine performs all of the
8390 transformations that are common to the equality/inequality
8391 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8392 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8393 fold_binary should call fold_binary. Fold a comparison with
8394 tree code CODE and type TYPE with operands OP0 and OP1. Return
8395 the folded comparison or NULL_TREE. */
8397 static tree
8399 {
8412 /* If one arg is a real or integer constant, put it last. */
8416 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8423 {
8427 tree lhs;
8434 /* If the constant operation overflowed this can be
8435 simplified as a comparison against INT_MAX/INT_MIN. */
8438 {
8442 /* Get the sign of the constant on the lhs if the
8443 operation were VARIABLE + CONST1. */
8447 /* The sign of the constant determines if we overflowed
8448 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8449 Canonicalize to the INT_MIN overflow by swapping the comparison
8450 if necessary. */
8454 /* We now can look at the canonicalized case
8455 VARIABLE + 1 CODE2 INT_MIN
8456 and decide on the result. */
8465 }
8470 {
8472 "when changing X +- C1 cmp C2 to "
8474 WARN_STRICT_OVERFLOW_COMPARISON);
8476 }
8477 }
8479 /* For comparisons of pointers we can decompose it to a compile time
8480 comparison of the base objects and the offsets into the object.
8481 This requires at least one operand being an ADDR_EXPR or a
8482 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8488 {
8495 /* Get base and offset for the access. Strip ADDR_EXPR for
8496 get_inner_reference, but put it back by stripping INDIRECT_REF
8497 off the base object if possible. indirect_baseN will be true
8498 if baseN is not an address but refers to the object itself. */
8501 {
8507 else
8509 }
8511 {
8514 }
8518 {
8524 else
8526 }
8528 {
8531 }
8533 /* If we have equivalent bases we might be able to simplify. */
8536 {
8537 /* We can fold this expression to a constant if the non-constant
8538 offset parts are equal. */
8542 {
8544 {
8558 }
8559 }
8560 /* We can simplify the comparison to a comparison of the variable
8561 offset parts if the constant offset parts are equal.
8562 Be careful to use signed size type here because otherwise we
8563 mess with array offsets in the wrong way. This is possible
8564 because pointer arithmetic is restricted to retain within an
8565 object and overflow on pointer differences is undefined as of
8566 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8568 {
8569 tree signed_size_type_node;
8572 /* By converting to signed size type we cover middle-end pointer
8573 arithmetic which operates on unsigned pointer types of size
8574 type size and ARRAY_REF offsets which are properly sign or
8575 zero extended from their type in case it is narrower than
8576 size type. */
8579 else
8583 else
8587 }
8588 }
8589 /* For non-equal bases we can simplify if they are addresses
8590 of local binding decls or constants. */
8592 /* We know that !operand_equal_p (base0, base1, 0)
8593 because the if condition was false. But make
8594 sure two decls are not the same. */
8608 {
8613 }
8614 /* For equal offsets we can simplify to a comparison of the
8615 base addresses. */
8617 && (indirect_base0
8619 && (indirect_base1
8624 {
8630 }
8631 }
8633 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8634 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8635 the resulting offset is smaller in absolute value than the
8636 original one. */
8644 {
8649 tree cst;
8651 "occur when combining constants around "
8654 /* Put the constant on the side where it doesn't overflow and is
8655 of lower absolute value than before. */
8661 {
8664 variable1,
8667 }
8674 {
8679 variable2);
8680 }
8681 }
8683 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8684 signed arithmetic case. That form is created by the compiler
8685 often enough for folding it to be of value. One example is in
8686 computing loop trip counts after Operator Strength Reduction. */
8692 {
8701 "eliminating multiplication in comparison "
8703 WARN_STRICT_OVERFLOW_COMPARISON);
8705 /* If const1 is negative we swap the sense of the comparison. */
8710 }
8717 {
8725 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8730 /* (-a) CMP (-b) -> b CMP a */
8737 {
8738 REAL_VALUE_TYPE cst;
8741 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8748 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8749 /* a CMP (-0) -> a CMP 0 */
8754 /* x != NaN is always true, other ops are always false. */
8757 {
8760 }
8762 /* Fold comparisons against infinity. */
8764 {
8768 }
8769 }
8771 /* If this is a comparison of a real constant with a PLUS_EXPR
8772 or a MINUS_EXPR of a real constant, we can convert it into a
8773 comparison with a revised real constant as long as no overflow
8774 occurs when unsafe_math_optimizations are enabled. */
8786 /* Likewise, we can simplify a comparison of a real constant with
8787 a MINUS_EXPR whose first operand is also a real constant, i.e.
8788 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
8789 floating-point types only if -fassociative-math is set. */
8800 /* Fold comparisons against built-in math functions. */
8802 && flag_unsafe_math_optimizations
8804 {
8808 {
8812 }
8813 }
8814 }
8819 {
8820 /* If we are widening one operand of an integer comparison,
8821 see if the other operand is similarly being widened. Perhaps we
8822 can do the comparison in the narrower type. */
8827 /* Or if we are changing signedness. */
8831 }
8833 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8834 constant, we can simplify it. */
8839 {
8843 }
8845 /* Simplify comparison of something with itself. (For IEEE
8846 floating-point, we can only do some of these simplifications.) */
8848 {
8850 {
8865 /* For NE, we can only do this simplification if integer
8866 or we don't honor IEEE floating point NaNs. */
8870 /* ... fall through ... */
8876 }
8877 }
8879 /* If we are comparing an expression that just has comparisons
8880 of two integer values, arithmetic expressions of those comparisons,
8881 and constants, we can simplify it. There are only three cases
8882 to check: the two values can either be equal, the first can be
8883 greater, or the second can be greater. Fold the expression for
8884 those three values. Since each value must be 0 or 1, we have
8885 eight possibilities, each of which corresponds to the constant 0
8886 or 1 or one of the six possible comparisons.
8888 This handles common cases like (a > b) == 0 but also handles
8889 expressions like ((x > y) - (y > x)) > 0, which supposedly
8890 occur in macroized code. */
8893 {
8898 /* Don't handle degenerate cases here; they should already
8899 have been handled anyway. */
8908 {
8912 /* We can't just pass T to eval_subst in case cval1 or cval2
8913 was the same as ARG1. */
8915 tree high_result
8919 arg1);
8920 tree equal_result
8924 arg1);
8925 tree low_result
8929 arg1);
8931 /* All three of these results should be 0 or 1. Confirm they are.
8932 Then use those values to select the proper code to use. */
8937 {
8938 /* Make a 3-bit mask with the high-order bit being the
8939 value for `>', the next for '=', and the low for '<'. */
8943 {
8945 /* Always false. */
8966 /* Always true. */
8968 }
8973 }
8974 }
8975 }
8977 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8978 into a single range test. */
8986 {
8990 }
8992 /* Fold ~X op ~Y as Y op X. */
8995 {
9000 }
9002 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9005 {
9011 }
9014 }
9017 /* Subroutine of fold_binary. Optimize complex multiplications of the
9018 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9019 argument EXPR represents the expression "z" of type TYPE. */
9021 static tree
9023 {
9028 {
9031 }
9033 {
9036 }
9037 else
9038 {
9042 }
9051 }
9054 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9055 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9056 guarantees that P and N have the same least significant log2(M) bits.
9057 N is not otherwise constrained. In particular, N is not normalized to
9058 0 <= N < M as is common. In general, the precise value of P is unknown.
9059 M is chosen as large as possible such that constant N can be determined.
9061 Returns M and sets *RESIDUE to N. */
9063 static unsigned HOST_WIDE_INT
9065 {
9072 {
9075 {
9077 tree offset;
9085 {
9088 else
9089 /* We don't handle more complicated offset expressions. */
9091 }
9092 }
9096 }
9098 {
9111 {
9114 }
9116 {
9119 {
9122 /* Compute the greatest power-of-2 divisor of op1. */
9126 /* If align is non-zero and less than *modulus, replace
9127 *modulus with align., If align is 0, then either op1 is 0
9128 or the greatest power-of-2 divisor of op1 doesn't fit in an
9129 unsigned HOST_WIDE_INT. In either case, no additional
9130 constraint is imposed. */
9135 }
9136 }
9137 }
9139 /* If we get here, we were unable to determine anything useful about the
9140 expression. */
9142 }
9145 /* Fold a binary expression of code CODE and type TYPE with operands
9146 OP0 and OP1. Return the folded expression if folding is
9147 successful. Otherwise, return NULL_TREE. */
9149 tree
9151 {
9166 /* Strip any conversions that don't change the mode. This is
9167 safe for every expression, except for a comparison expression
9168 because its signedness is derived from its operands. So, in
9169 the latter case, only strip conversions that don't change the
9170 signedness.
9172 Note that this is done as an internal manipulation within the
9173 constant folder, in order to find the simplest representation
9174 of the arguments so that their form can be studied. In any
9175 cases, the appropriate type conversions should be put back in
9176 the tree that will get out of the constant folder. */
9179 {
9182 }
9183 else
9184 {
9187 }
9189 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9190 constant but we can't do arithmetic on them. */
9197 {
9199 {
9200 /* Make sure type and arg0 have the same saturating flag. */
9204 }
9207 else
9211 {
9215 }
9216 }
9218 /* If this is a commutative operation, and ARG0 is a constant, move it
9219 to ARG1 to reduce the number of tests below. */
9224 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9226 First check for cases where an arithmetic operation is applied to a
9227 compound, conditional, or comparison operation. Push the arithmetic
9228 operation inside the compound or conditional to see if any folding
9229 can then be done. Convert comparison to conditional for this purpose.
9230 The also optimizes non-constant cases that used to be done in
9231 expand_expr.
9233 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9234 one of the operands is a comparison and the other is a comparison, a
9235 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9236 code below would make the expression more complex. Change it to a
9237 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9238 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9250 {
9254 boolean_type_node,
9262 }
9266 {
9272 op1));
9281 {
9287 }
9290 {
9296 }
9297 }
9300 {
9302 /* 0 +p index -> (type)index */
9306 /* PTR +p 0 -> PTR */
9310 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9317 /* index +p PTR -> PTR +p index */
9324 /* (PTR +p B) +p A -> PTR +p (B + A) */
9326 {
9327 tree inner;
9335 }
9337 /* PTR_CST +p CST -> CST1 */
9341 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9342 of the array. Loop optimizer sometimes produce this type of
9343 expressions. */
9345 {
9349 }
9354 /* PTR + INT -> (INT)(PTR p+ INT) */
9359 arg0,
9361 /* INT + PTR -> (INT)(PTR p+ INT) */
9366 arg1,
9368 /* A + (-B) -> A - B */
9373 /* (-A) + B -> B - A */
9381 {
9382 /* Convert ~A + 1 to -A. */
9387 /* ~X + X is -1. */
9390 {
9395 {
9398 }
9399 }
9401 /* X + ~X is -1. */
9404 {
9409 {
9412 }
9413 }
9415 /* X + (X / CST) * -CST is X % CST. */
9420 {
9428 }
9429 }
9431 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9432 same or one. Make sure type is not saturating.
9433 fold_plusminus_mult_expr will re-associate. */
9438 {
9442 }
9445 {
9449 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9450 with a constant, and the two constants have no bits in common,
9451 we should treat this as a BIT_IOR_EXPR since this may produce more
9452 simplifications. */
9460 {
9463 }
9465 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9466 (plus (plus (mult) (mult)) (foo)) so that we can
9467 take advantage of the factoring cases below. */
9474 {
9480 else
9502 parg1)));
9503 }
9504 }
9505 else
9506 {
9507 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9511 /* Likewise if the operands are reversed. */
9515 /* Convert X + -C into X - C. */
9518 {
9524 }
9526 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9527 to __complex__ ( x, y ). This is not the same for SNaNs or
9528 if signed zeros are involved. */
9532 {
9539 {
9543 {
9549 }
9551 {
9557 }
9558 }
9559 }
9567 /* Convert x+x into x*2.0. */
9573 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9574 We associate floats only if the user has specified
9575 -fassociative-math. */
9579 {
9584 {
9585 tree tree0;
9588 }
9589 }
9590 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9591 We associate floats only if the user has specified
9592 -fassociative-math. */
9596 {
9601 {
9602 tree tree0;
9605 }
9606 }
9607 }
9609 bit_rotate:
9610 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9611 is a rotate of A by C1 bits. */
9612 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9613 is a rotate of A by B bits. */
9614 {
9616 tree rtype;
9625 /* Only create rotates in complete modes. Other cases are not
9626 expanded properly. */
9628 {
9647 {
9655 TYPE_PRECISION
9660 ? LROTATE_EXPR
9663 }
9665 {
9673 TYPE_PRECISION
9678 ? LROTATE_EXPR
9681 }
9682 }
9683 }
9685 associate:
9686 /* In most languages, can't associate operations on floats through
9687 parentheses. Rather than remember where the parentheses were, we
9688 don't associate floats at all, unless the user has specified
9689 -fassociative-math.
9690 And, we need to make sure type is not saturating. */
9694 {
9699 /* Split both trees into variables, constants, and literals. Then
9700 associate each group together, the constants with literals,
9701 then the result with variables. This increases the chances of
9702 literals being recombined later and of generating relocatable
9703 expressions for the sum of a constant and literal. */
9708 /* With undefined overflow we can only associate constants
9709 with one variable. */
9713 {
9721 /* The only case we can still associate with two variables
9722 is if they are the same, modulo negation. */
9725 }
9727 /* Only do something if we found more than two objects. Otherwise,
9728 nothing has changed and we risk infinite recursion. */
9734 {
9735 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9744 /* Preserve the MINUS_EXPR if the negative part of the literal is
9745 greater than the positive part. Otherwise, the multiplicative
9746 folding code (i.e extract_muldiv) may be fooled in case
9747 unsigned constants are subtracted, like in the following
9748 example: ((X*2 + 4) - 8U)/2. */
9750 {
9754 {
9758 }
9759 else
9760 {
9764 }
9765 }
9767 {
9772 else
9773 {
9779 }
9780 }
9785 }
9786 }
9791 /* Pointer simplifications for subtraction, simple reassociations. */
9793 {
9794 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
9797 {
9805 }
9806 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
9808 {
9814 }
9815 }
9816 /* A - (-B) -> A + B */
9820 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9829 /* Convert -A - 1 to ~A. */
9837 /* Convert -1 - A to ~A. */
9843 /* X - (X / CST) * CST is X % CST. */
9856 {
9862 /* Fold A - (A & B) into ~B & A. */
9865 {
9867 {
9872 }
9874 {
9879 }
9880 }
9882 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
9883 any power of 2 minus 1. */
9888 {
9894 {
9898 }
9899 }
9900 }
9902 /* See if ARG1 is zero and X - ARG1 reduces to X. */
9906 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
9907 ARG0 is zero and X + ARG0 reduces to X, since that would mean
9908 (-ARG1 + ARG0) reduces to -ARG1. */
9912 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9913 __complex__ ( x, -y ). This is not the same for SNaNs or if
9914 signed zeros are involved. */
9918 {
9925 {
9929 {
9931 arg1r ? arg1r
9936 }
9938 {
9942 arg1i ? arg1i
9945 }
9946 }
9947 }
9949 /* Fold &x - &x. This can happen from &x.foo - &x.
9950 This is unsafe for certain floats even in non-IEEE formats.
9951 In IEEE, it is unsafe because it does wrong for NaNs.
9952 Also note that operand_equal_p is always false if an operand
9953 is volatile. */
9959 /* A - B -> A + (-B) if B is easily negatable. */
9962 /* Avoid this transformation if B is a positive REAL_CST. */
9970 /* Try folding difference of addresses. */
9971 {
9972 HOST_WIDE_INT diff;
9978 }
9980 /* Fold &a[i] - &a[j] to i-j. */
9985 {
9990 {
9998 }
9999 }
10007 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10008 same or one. Make sure type is not saturating.
10009 fold_plusminus_mult_expr will re-associate. */
10014 {
10018 }
10023 /* (-A) * (-B) -> A * B */
10034 {
10039 /* Transform x * -1 into -x. Make sure to do the negation
10040 on the original operand with conversions not stripped
10041 because we can only strip non-sign-changing conversions. */
10044 /* Transform x * -C into -x * C if x is easily negatable. */
10053 /* (a * (1 << b)) is (a << b) */
10067 {
10070 "occur when simplifying "
10072 WARN_STRICT_OVERFLOW_MISC);
10074 }
10076 /* Optimize z * conj(z) for integer complex numbers. */
10083 }
10084 else
10085 {
10086 /* Maybe fold x * 0 to 0. The expressions aren't the same
10087 when x is NaN, since x * 0 is also NaN. Nor are they the
10088 same in modes with signed zeros, since multiplying a
10089 negative value by 0 gives -0, not +0. */
10094 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10099 /* Transform x * -1.0 into -x. */
10104 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10105 the result for floating point types due to rounding so it is applied
10106 only if -fassociative-math was specify. */
10111 {
10117 }
10119 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10121 {
10124 {
10127 }
10128 }
10130 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10131 This is not the same for NaNs or if signed zeros are
10132 involved. */
10138 {
10150 }
10152 /* Optimize z * conj(z) for floating point complex numbers.
10153 Guarded by flag_unsafe_math_optimizations as non-finite
10154 imaginary components don't produce scalar results. */
10165 {
10169 /* Optimizations of root(...)*root(...). */
10171 {
10176 /* Optimize sqrt(x)*sqrt(x) as x. */
10182 /* Optimize root(x)*root(y) as root(x*y). */
10186 }
10188 /* Optimize expN(x)*expN(y) as expN(x+y). */
10190 {
10196 }
10198 /* Optimizations of pow(...)*pow(...). */
10202 {
10208 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10210 {
10214 }
10216 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10218 {
10222 }
10223 }
10225 /* Optimize tan(x)*cos(x) as sin(x). */
10234 {
10239 }
10241 /* Optimize x*pow(x,c) as pow(x,c+1). */
10245 {
10251 {
10253 REAL_VALUE_TYPE c;
10254 tree arg;
10260 }
10261 }
10263 /* Optimize pow(x,c)*x as pow(x,c+1). */
10267 {
10273 {
10275 REAL_VALUE_TYPE c;
10276 tree arg;
10282 }
10283 }
10285 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10288 {
10292 {
10295 }
10296 }
10297 }
10298 }
10302 bit_ior:
10310 /* ~X | X is -1. */
10313 {
10317 }
10319 /* X | ~X is -1. */
10322 {
10326 }
10328 /* Canonicalize (X & C1) | C2. */
10332 {
10340 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10345 {
10349 }
10350 else
10351 {
10355 }
10357 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10362 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10363 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10364 mode which allows further optimizations. */
10374 {
10375 unsigned HOST_WIDE_INT mask
10379 {
10383 }
10384 }
10391 arg1);
10392 }
10394 /* (X & Y) | Y is (X, Y). */
10398 /* (X & Y) | X is (Y, X). */
10403 /* X | (X & Y) is (Y, X). */
10408 /* X | (Y & X) is (Y, X). */
10418 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10420 This results in more efficient code for machines without a NAND
10421 instruction. Combine will canonicalize to the first form
10422 which will allow use of NAND instructions provided by the
10423 backend if they exist. */
10426 {
10433 }
10435 /* See if this can be simplified into a rotate first. If that
10436 is unsuccessful continue in the association code. */
10447 /* ~X ^ X is -1. */
10450 {
10454 }
10456 /* X ^ ~X is -1. */
10459 {
10463 }
10465 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10466 with a constant, and the two constants have no bits in common,
10467 we should treat this as a BIT_IOR_EXPR since this may produce more
10468 simplifications. */
10476 {
10479 }
10481 /* (X | Y) ^ X -> Y & ~ X*/
10484 {
10487 arg1);
10491 }
10493 /* (Y | X) ^ X -> Y & ~ X*/
10496 {
10499 arg1);
10503 }
10505 /* X ^ (X | Y) -> Y & ~ X*/
10508 {
10511 arg0);
10515 }
10517 /* X ^ (Y | X) -> Y & ~ X*/
10520 {
10523 arg0);
10527 }
10529 /* Convert ~X ^ ~Y to X ^ Y. */
10536 /* Convert ~X ^ C to X ^ ~C. */
10543 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10550 /* Fold (X & Y) ^ Y as ~X & Y. */
10553 {
10558 }
10559 /* Fold (X & Y) ^ X as ~Y & X. */
10563 {
10568 }
10569 /* Fold X ^ (X & Y) as X & ~Y. */
10572 {
10577 }
10578 /* Fold X ^ (Y & X) as ~Y & X. */
10582 {
10587 }
10589 /* See if this can be simplified into a rotate first. If that
10590 is unsuccessful continue in the association code. */
10601 /* ~X & X is always zero. */
10606 /* X & ~X is always zero. */
10611 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10615 {
10624 }
10626 /* (X | Y) & Y is (X, Y). */
10630 /* (X | Y) & X is (Y, X). */
10635 /* X & (X | Y) is (Y, X). */
10640 /* X & (Y | X) is (Y, X). */
10646 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10650 {
10656 }
10657 /* Fold ~X & 1 as (X & 1) == 0. */
10660 {
10666 }
10668 /* Fold (X ^ Y) & Y as ~X & Y. */
10671 {
10676 }
10677 /* Fold (X ^ Y) & X as ~Y & X. */
10681 {
10686 }
10687 /* Fold X & (X ^ Y) as X & ~Y. */
10690 {
10695 }
10696 /* Fold X & (Y ^ X) as ~Y & X. */
10700 {
10705 }
10710 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10713 {
10714 unsigned int prec
10721 }
10723 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10725 This results in more efficient code for machines without a NOR
10726 instruction. Combine will canonicalize to the first form
10727 which will allow use of NOR instructions provided by the
10728 backend if they exist. */
10731 {
10738 }
10740 /* If arg0 is derived from the address of an object or function, we may
10741 be able to fold this expression using the object or function's
10742 alignment. */
10744 {
10750 /* This works because modulus is a power of 2. If this weren't the
10751 case, we'd have to replace it by its greatest power-of-2
10752 divisor: modulus & -modulus. */
10755 }
10757 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
10758 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
10759 if the new mask might be further optimized. */
10768 {
10770 unsigned HOST_WIDE_INT mask
10780 {
10783 /* See if more bits can be proven as zero because of
10784 zero extension. */
10787 {
10792 {
10794 /* See if we can shorten the right shift. */
10797 }
10798 }
10802 /* For arithmetic shift if sign bit could be set, zerobits
10803 can contain actually sign bits, so no transformation is
10804 possible, unless MASK masks them all away. In that
10805 case the shift needs to be converted into logical shift. */
10808 {
10811 else
10813 }
10814 }
10816 /* ((X << 16) & 0xff00) is (X, 0). */
10822 {
10825 /* Only do the transformation if NEWMASK is some integer
10826 mode's mask. */
10833 {
10835 {
10841 }
10842 else
10846 newmask));
10847 }
10848 }
10849 }
10854 /* Don't touch a floating-point divide by zero unless the mode
10855 of the constant can represent infinity. */
10861 /* Optimize A / A to 1.0 if we don't care about
10862 NaNs or Infinities. Skip the transformation
10863 for non-real operands. */
10868 {
10872 }
10874 /* The complex version of the above A / A optimization. */
10877 {
10881 {
10883 /* omit_two_operands will call fold_convert for us. */
10885 }
10886 }
10888 /* (-A) / (-B) -> A / B */
10898 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
10903 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
10908 /* If ARG1 is a constant, we can convert this to a multiply by the
10909 reciprocal. This does not have the same rounding properties,
10910 so only do this if -freciprocal-math. We can actually
10911 always safely do it if ARG1 is a power of two, but it's hard to
10912 tell if it is or not in a portable manner. */
10914 {
10919 /* Find the reciprocal if optimizing and the result is exact. */
10921 {
10922 REAL_VALUE_TYPE r;
10925 {
10929 }
10930 }
10931 }
10932 /* Convert A/B/C to A/(B*C). */
10939 /* Convert A/(B/C) to (A/B)*C. */
10947 /* Convert C1/(X*C2) into (C1/C2)/X. */
10952 {
10958 }
10961 {
10965 /* Optimize sin(x)/cos(x) as tan(x). */
10971 {
10976 }
10978 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
10984 {
10988 {
10992 }
10993 }
10995 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
10996 NaNs or Infinities. */
11000 {
11007 {
11012 }
11013 }
11015 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11016 NaNs or Infinities. */
11020 {
11027 {
11031 {
11035 tmp);
11036 }
11037 }
11038 }
11040 /* Optimize pow(x,c)/x as pow(x,c-1). */
11044 {
11050 {
11052 REAL_VALUE_TYPE c;
11053 tree arg;
11059 }
11060 }
11062 /* Optimize a/root(b/c) into a*root(c/b). */
11064 {
11068 {
11077 }
11078 }
11080 /* Optimize x/expN(y) into x*expN(-y). */
11082 {
11087 }
11089 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11093 {
11100 }
11101 }
11106 /* Simplify A / (B << N) where A and B are positive and B is
11107 a power of 2, to A >> (N + log2(B)). */
11112 {
11115 {
11122 WARN_STRICT_OVERFLOW_MISC);
11128 }
11129 }
11131 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11132 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11138 /* Fall thru */
11147 /* X / -1 is -X. */
11154 /* Convert -A / -B to A / B when the type is signed and overflow is
11155 undefined. */
11159 {
11162 "when distributing negation across "
11164 WARN_STRICT_OVERFLOW_MISC);
11168 }
11172 {
11175 "when distributing negation across "
11177 WARN_STRICT_OVERFLOW_MISC);
11180 }
11182 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11183 operation, EXACT_DIV_EXPR.
11185 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11186 At one time others generated faster code, it's not clear if they do
11187 after the last round to changes to the DIV code in expmed.c. */
11196 {
11200 WARN_STRICT_OVERFLOW_MISC);
11202 }
11210 /* X % 1 is always zero, but be sure to preserve any side
11211 effects in X. */
11215 /* X % 0, return X % 0 unchanged so that we can get the
11216 proper warnings and errors. */
11220 /* 0 % X is always zero, but be sure to preserve any side
11221 effects in X. Place this after checking for X == 0. */
11225 /* X % -1 is zero. */
11232 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11233 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11238 {
11240 /* Also optimize A % (C << N) where C is a power of 2,
11241 to A & ((C << N) - 1). */
11246 {
11251 "occur when simplifying "
11253 WARN_STRICT_OVERFLOW_MISC);
11257 }
11258 }
11260 /* X % -C is the same as X % C. */
11267 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11272 /* X % -Y is the same as X % Y. */
11283 {
11287 WARN_STRICT_OVERFLOW_MISC);
11289 }
11300 /* Optimize -1 >> x for arithmetic right shifts. */
11303 /* ... fall through ... */
11306 shift:
11312 /* Since negative shift count is not well-defined,
11313 don't try to compute it in the compiler. */
11317 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11322 {
11326 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11327 being well defined. */
11329 {
11334 else
11336 }
11340 }
11342 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11343 into x & ((unsigned)-1 >> c) for unsigned types. */
11351 {
11354 tree lshift;
11355 tree arg00;
11358 {
11365 }
11366 }
11368 /* Rewrite an LROTATE_EXPR by a constant into an
11369 RROTATE_EXPR by a new constant. */
11371 {
11376 }
11378 /* If we have a rotate of a bit operation with the rotate count and
11379 the second operand of the bit operation both constant,
11380 permute the two operations. */
11392 /* Two consecutive rotates adding up to the precision of the
11393 type can be ignored. */
11404 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11405 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11406 if the latter can be further optimized. */
11411 {
11414 arg1);
11417 arg1);
11421 }
11449 /* Note that the operands of this must be ints
11450 and their values must be 0 or 1.
11451 ("true" is a fixed value perhaps depending on the language.) */
11452 /* If first arg is constant zero, return it. */
11456 /* If either arg is constant true, drop it. */
11460 /* Preserve sequence points. */
11463 /* If second arg is constant zero, result is zero, but first arg
11464 must be evaluated. */
11467 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11468 case will be handled here. */
11472 /* !X && X is always false. */
11476 /* X && !X is always false. */
11481 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11482 means A >= Y && A != MAX, but in this case we know that
11483 A < X <= MAX. */
11487 {
11495 }
11497 truth_andor:
11498 /* We only do these simplifications if we are optimizing. */
11502 /* Check for things like (A || B) && (A || C). We can convert this
11503 to A || (B && C). Note that either operator can be any of the four
11504 truth and/or operations and the transformation will still be
11505 valid. Also note that we only care about order for the
11506 ANDIF and ORIF operators. If B contains side effects, this
11507 might change the truth-value of A. */
11514 {
11534 /* This case if tricky because we must either have commutative
11535 operators or else A10 must not have side-effects. */
11541 a01);
11542 }
11544 /* See if we can build a range comparison. */
11548 /* Check for the possibility of merging component references. If our
11549 lhs is another similar operation, try to merge its rhs with our
11550 rhs. Then try to merge our lhs and rhs. */
11562 /* Note that the operands of this must be ints
11563 and their values must be 0 or true.
11564 ("true" is a fixed value perhaps depending on the language.) */
11565 /* If first arg is constant true, return it. */
11569 /* If either arg is constant zero, drop it. */
11573 /* Preserve sequence points. */
11576 /* If second arg is constant true, result is true, but we must
11577 evaluate first arg. */
11580 /* Likewise for first arg, but note this only occurs here for
11581 TRUTH_OR_EXPR. */
11585 /* !X || X is always true. */
11589 /* X || !X is always true. */
11597 /* If the second arg is constant zero, drop it. */
11600 /* If the second arg is constant true, this is a logical inversion. */
11602 {
11603 /* Only call invert_truthvalue if operand is a truth value. */
11606 else
11609 }
11610 /* Identical arguments cancel to zero. */
11614 /* !X ^ X is always true. */
11619 /* X ^ !X is always true. */
11632 /* bool_var != 0 becomes bool_var. */
11637 /* bool_var == 1 becomes bool_var. */
11642 /* bool_var != 1 becomes !bool_var. */
11647 /* bool_var == 0 becomes !bool_var. */
11652 /* If this is an equality comparison of the address of two non-weak,
11653 unaliased symbols neither of which are extern (since we do not
11654 have access to attributes for externs), then we know the result. */
11667 {
11668 /* We know that we're looking at the address of two
11669 non-weak, unaliased, static _DECL nodes.
11671 It is both wasteful and incorrect to call operand_equal_p
11672 to compare the two ADDR_EXPR nodes. It is wasteful in that
11673 all we need to do is test pointer equality for the arguments
11674 to the two ADDR_EXPR nodes. It is incorrect to use
11675 operand_equal_p as that function is NOT equivalent to a
11676 C equality test. It can in fact return false for two
11677 objects which would test as equal using the C equality
11678 operator. */
11682 type);
11683 }
11685 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11686 a MINUS_EXPR of a constant, we can convert it into a comparison with
11687 a revised constant as long as no overflow occurs. */
11699 /* Similarly for a NEGATE_EXPR. */
11707 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11716 /* Transform comparisons of the form X +- C CMP X. */
11722 {
11729 else
11732 }
11734 /* If we have X - Y == 0, we can convert that to X == Y and similarly
11735 for !=. Don't do this for ordered comparisons due to overflow. */
11741 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11746 /* If this is an EQ or NE comparison with zero and ARG0 is
11747 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11748 two operations, but the latter can be done in one less insn
11749 on machines that have only two-operand insns or on which a
11750 constant cannot be the first operand. */
11753 {
11758 {
11765 }
11768 {
11775 }
11776 }
11778 /* If this is an NE or EQ comparison of zero against the result of a
11779 signed MOD operation whose second operand is a power of 2, make
11780 the MOD operation unsigned since it is simpler and equivalent. */
11788 {
11798 }
11800 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11801 C1 is a valid shift constant, and C2 is a power of two, i.e.
11802 a single bit. */
11806 == INTEGER_CST
11809 {
11814 /* Check for a valid shift count. */
11817 {
11821 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11822 can be rewritten as (X & (C2 << C1)) != 0. */
11824 {
11828 }
11829 /* Otherwise, for signed (arithmetic) shifts,
11830 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11831 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11835 /* Otherwise, of unsigned (logical) shifts,
11836 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11837 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11838 else
11842 arg000);
11843 }
11844 }
11846 /* If this is an NE comparison of zero with an AND of one, remove the
11847 comparison since the AND will give the correct value. */
11854 /* If we have (A & C) == C where C is a power of 2, convert this into
11855 (A & C) != 0. Similarly for NE_EXPR. */
11861 integer_zero_node));
11863 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
11864 bit, then fold the expression into A < 0 or A >= 0. */
11869 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
11870 Similarly for NE_EXPR. */
11874 {
11883 }
11885 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
11886 Similarly for NE_EXPR. */
11890 {
11897 }
11899 /* Optimize comparisons of strlen vs zero to a compare of the
11900 first character of the string vs zero. To wit,
11901 strlen(ptr) == 0 => *ptr == 0
11902 strlen(ptr) != 0 => *ptr != 0
11903 Other cases should reduce to one of these two (or a constant)
11904 due to the return value of strlen being unsigned. */
11907 {
11915 {
11919 }
11920 }
11922 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
11923 of X. Similarly fold (X >> C) == 0 into X >= 0. */
11927 {
11934 {
11936 {
11939 }
11942 }
11943 }
11945 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
11951 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
11956 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
11963 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
11971 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
11972 (X & C) == 0 when C is a single bit. */
11977 {
11983 }
11985 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
11986 constant C is a power of two, i.e. a single bit. */
11993 {
11997 }
11999 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12000 when is C is a power of two, i.e. a single bit. */
12007 {
12013 }
12017 {
12020 }
12022 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12029 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12032 {
12044 arg01),
12052 arg01),
12060 arg00),
12068 arg00),
12070 }
12074 {
12081 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12082 operand_equal_p guarantees no side-effects so we don't need
12083 to use omit_one_operand on Z. */
12093 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12100 arg10);
12101 }
12103 /* Attempt to simplify equality/inequality comparisons of complex
12104 values. Only lower the comparison if the result is known or
12105 can be simplified to a single scalar comparison. */
12110 {
12115 {
12118 }
12119 else
12120 {
12123 }
12126 {
12129 }
12130 else
12131 {
12134 }
12138 {
12140 {
12145 }
12146 else
12147 {
12152 }
12153 }
12157 {
12159 {
12164 }
12165 else
12166 {
12171 }
12172 }
12173 }
12185 /* Transform comparisons of the form X +- C CMP X. */
12192 {
12199 else
12202 /* (X - c) > X becomes false. */
12206 {
12210 "occur when assuming that (X - c) > X "
12212 WARN_STRICT_OVERFLOW_ALL);
12214 }
12216 /* Likewise (X + c) < X becomes false. */
12220 {
12224 "occur when assuming that "
12226 WARN_STRICT_OVERFLOW_ALL);
12228 }
12230 /* Convert (X - c) <= X to true. */
12235 {
12239 "occur when assuming that "
12241 WARN_STRICT_OVERFLOW_ALL);
12243 }
12245 /* Convert (X + c) >= X to true. */
12250 {
12254 "occur when assuming that "
12256 WARN_STRICT_OVERFLOW_ALL);
12258 }
12261 {
12262 /* Convert X + c > X and X - c < X to true for integers. */
12266 {
12269 "not occur when assuming that "
12271 WARN_STRICT_OVERFLOW_ALL);
12273 }
12278 {
12281 "not occur when assuming that "
12283 WARN_STRICT_OVERFLOW_ALL);
12285 }
12287 /* Convert X + c <= X and X - c >= X to false for integers. */
12291 {
12294 "not occur when assuming that "
12296 WARN_STRICT_OVERFLOW_ALL);
12298 }
12303 {
12306 "not occur when assuming that "
12308 WARN_STRICT_OVERFLOW_ALL);
12310 }
12311 }
12312 }
12314 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
12315 This transformation affects the cases which are handled in later
12316 optimizations involving comparisons with non-negative constants. */
12320 {
12322 {
12327 }
12329 {
12334 }
12335 }
12337 /* Comparisons with the highest or lowest possible integer of
12338 the specified precision will have known values. */
12339 {
12347 {
12348 HOST_WIDE_INT signed_max_hi;
12353 {
12360 {
12364 }
12365 else
12366 {
12370 }
12371 }
12372 else
12373 {
12382 {
12385 }
12386 else
12387 {
12390 }
12391 }
12396 {
12409 /* The GE_EXPR and LT_EXPR cases above are not normally
12410 reached because of previous transformations. */
12414 }
12416 == max_hi
12419 {
12425 arg1);
12431 arg1);
12434 }
12436 == min_hi
12439 {
12454 }
12456 == min_hi
12459 {
12464 arg1);
12469 arg1);
12472 }
12477 /* We will flip the signedness of the comparison operator
12478 associated with the mode of arg1, so the sign bit is
12479 specified by this mode. Check that arg1 is the signed
12480 max associated with this sign bit. */
12482 /* signed_type does not work on pointer types. */
12484 {
12485 /* The following case also applies to X < signed_max+1
12486 and X >= signed_max+1 because previous transformations. */
12488 {
12489 tree st;
12494 }
12495 }
12496 }
12497 }
12499 /* If we are comparing an ABS_EXPR with a constant, we can
12500 convert all the cases into explicit comparisons, but they may
12501 well not be faster than doing the ABS and one comparison.
12502 But ABS (X) <= C is a range comparison, which becomes a subtraction
12503 and a comparison, and is probably faster. */
12517 /* Convert ABS_EXPR<x> >= 0 to true. */
12524 {
12527 "when simplifying comparison of "
12529 WARN_STRICT_OVERFLOW_CONDITIONAL);
12531 }
12533 /* Convert ABS_EXPR<x> < 0 to false. */
12538 {
12541 "when simplifying comparison of "
12543 WARN_STRICT_OVERFLOW_CONDITIONAL);
12545 }
12547 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12548 and similarly for >= into !=. */
12564 return
12583 {
12587 }
12589 /* If the first operand is NaN, the result is constant. */
12593 {
12595 ? integer_zero_node
12598 }
12600 /* If the second operand is NaN, the result is constant. */
12604 {
12606 ? integer_zero_node
12609 }
12611 /* Simplify unordered comparison of something with itself. */
12617 && !flag_trapping_math
12621 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12622 {
12633 }
12638 /* When pedantic, a compound expression can be neither an lvalue
12639 nor an integer constant expression. */
12642 /* Don't let (0, 0) be null pointer constant. */
12656 /* An ASSERT_EXPR should never be passed to fold_binary. */
12662 }
12664 /* Callback for walk_tree, looking for LABEL_EXPR.
12665 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12666 Do not check the sub-tree of GOTO_EXPR. */
12668 static tree
12672 {
12674 {
12679 /* no break */
12682 }
12683 }
12685 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12686 accessible from outside the sub-tree. Returns NULL_TREE if no
12687 addressable label is found. */
12689 static bool
12691 {
12693 }
12695 /* Fold a ternary expression of code CODE and type TYPE with operands
12696 OP0, OP1, and OP2. Return the folded expression if folding is
12697 successful. Otherwise, return NULL_TREE. */
12699 tree
12701 {
12702 tree tem;
12709 /* Strip any conversions that don't change the mode. This is safe
12710 for every expression, except for a comparison expression because
12711 its signedness is derived from its operands. So, in the latter
12712 case, only strip conversions that don't change the signedness.
12714 Note that this is done as an internal manipulation within the
12715 constant folder, in order to find the simplest representation of
12716 the arguments so that their form can be studied. In any cases,
12717 the appropriate type conversions should be put back in the tree
12718 that will get out of the constant folder. */
12720 {
12723 }
12726 {
12729 }
12732 {
12736 {
12742 }
12746 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12747 so all simple results must be passed through pedantic_non_lvalue. */
12749 {
12752 /* Only optimize constant conditions when the selected branch
12753 has the same type as the COND_EXPR. This avoids optimizing
12754 away "c ? x : throw", where the throw has a void type.
12755 Avoid throwing away that operand which contains label. */
12762 }
12766 /* If we have A op B ? A : C, we may be able to convert this to a
12767 simpler expression, depending on the operation and the values
12768 of B and C. Signed zeros prevent all of these transformations,
12769 for reasons given above each one.
12771 Also try swapping the arguments and inverting the conditional. */
12776 {
12780 }
12784 op2,
12787 {
12790 {
12794 }
12795 }
12797 /* If the second operand is simpler than the third, swap them
12798 since that produces better jump optimization results. */
12801 {
12802 /* See if this can be inverted. If it can't, possibly because
12803 it was a floating-point inequality comparison, don't do
12804 anything. */
12808 }
12810 /* Convert A ? 1 : 0 to simply A. */
12813 /* If we try to convert OP0 to our type, the
12814 call to fold will try to move the conversion inside
12815 a COND, which will recurse. In that case, the COND_EXPR
12816 is probably the best choice, so leave it alone. */
12820 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12821 over COND_EXPR in cases such as floating point comparisons. */
12828 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12833 {
12834 /* sign_bit_p only checks ARG1 bits within A's precision.
12835 If <sign bit of A> has wider type than A, bits outside
12836 of A's precision in <sign bit of A> need to be checked.
12837 If they are all 0, this optimization needs to be done
12838 in unsigned A's type, if they are all 1 in signed A's type,
12839 otherwise this can't be done. */
12844 {
12846 HOST_WIDE_INT mask_hi;
12848 tree tem_type;
12856 {
12860 }
12861 else
12862 {
12866 }
12868 {
12872 }
12873 else
12879 {
12882 }
12885 {
12888 }
12889 else
12891 }
12898 arg1)));
12899 }
12901 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12902 already handled above. */
12907 {
12916 }
12918 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12919 is probably obsolete because the first operand should be a
12920 truth value (that's why we have the two cases above), but let's
12921 leave it in until we can confirm this for all front-ends. */
12932 /* Convert A ? B : 0 into A && B if A and B are truth values. */
12938 arg1);
12940 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
12944 {
12945 /* Only perform transformation if ARG0 is easily inverted. */
12950 arg1);
12951 }
12953 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
12957 {
12958 /* Only perform transformation if ARG0 is easily inverted. */
12963 op2);
12964 }
12966 /* Convert A ? 1 : B into A || B if A and B are truth values. */
12972 op2);
12977 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
12978 of fold_ternary on them. */
12985 {
12994 {
12999 else
13000 {
13002 tree value;
13006 }
13011 else
13013 }
13014 }
13020 }
13022 /* Perform constant folding and related simplification of EXPR.
13023 The related simplifications include x*1 => x, x*0 => 0, etc.,
13024 and application of the associative law.
13025 NOP_EXPR conversions may be removed freely (as long as we
13026 are careful not to change the type of the overall expression).
13027 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13028 but we can constant-fold them if they have constant operands. */
13030 #ifdef ENABLE_FOLD_CHECKING
13031 # define fold(x) fold_1 (x)
13033 static
13034 #endif
13035 tree
13037 {
13041 tree tem;
13043 /* Return right away if a constant. */
13047 /* CALL_EXPR-like objects with variable numbers of operands are
13048 treated specially. */
13050 {
13052 {
13055 }
13057 }
13061 {
13066 {
13084 }
13085 }
13088 {
13090 {
13097 {
13102 /* Find a matching index by means of a binary search. */
13104 {
13120 else
13122 }
13123 }
13126 }
13134 }
13136 #ifdef ENABLE_FOLD_CHECKING
13137 #undef fold
13143 /* When --enable-checking=fold, compute a digest of expr before
13144 and after actual fold call to see if fold did not accidentally
13145 change original expr. */
13147 tree
13149 {
13150 tree ret;
13153 htab_t ht;
13172 }
13174 void
13176 {
13179 htab_t ht;
13189 }
13191 static void
13193 {
13195 }
13197 static void
13199 {
13205 recursive_label:
13219 {
13220 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13224 }
13229 {
13230 /* Allow these fields to be modified. */
13231 tree tmp;
13238 {
13241 }
13242 }
13251 {
13254 {
13268 }
13272 {
13285 }
13302 {
13308 }
13313 {
13317 }
13328 {
13331 }
13341 }
13342 }
13344 /* Helper function for outputting the checksum of a tree T. When
13345 debugging with gdb, you can "define mynext" to be "next" followed
13346 by "call debug_fold_checksum (op0)", then just trace down till the
13347 outputs differ. */
13349 void
13351 {
13366 }
13368 #endif
13370 /* Fold a unary tree expression with code CODE of type TYPE with an
13371 operand OP0. Return a folded expression if successful. Otherwise,
13372 return a tree expression with code CODE of type TYPE with an
13373 operand OP0. */
13375 tree
13377 {
13378 tree tem;
13379 #ifdef ENABLE_FOLD_CHECKING
13382 htab_t ht;
13389 #endif
13395 #ifdef ENABLE_FOLD_CHECKING
13403 #endif
13405 }
13407 /* Fold a binary tree expression with code CODE of type TYPE with
13408 operands OP0 and OP1. Return a folded expression if successful.
13409 Otherwise, return a tree expression with code CODE of type TYPE
13410 with operands OP0 and OP1. */
13412 tree
13414 MEM_STAT_DECL)
13415 {
13416 tree tem;
13417 #ifdef ENABLE_FOLD_CHECKING
13423 htab_t ht;
13435 #endif
13441 #ifdef ENABLE_FOLD_CHECKING
13457 #endif
13459 }
13461 /* Fold a ternary tree expression with code CODE of type TYPE with
13462 operands OP0, OP1, and OP2. Return a folded expression if
13463 successful. Otherwise, return a tree expression with code CODE of
13464 type TYPE with operands OP0, OP1, and OP2. */
13466 tree
13468 MEM_STAT_DECL)
13469 {
13470 tree tem;
13471 #ifdef ENABLE_FOLD_CHECKING
13479 htab_t ht;
13496 #endif
13503 #ifdef ENABLE_FOLD_CHECKING
13527 #endif
13529 }
13531 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13532 arguments in ARGARRAY, and a null static chain.
13533 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13534 of type TYPE from the given operands as constructed by build_call_array. */
13536 tree
13538 {
13539 tree tem;
13540 #ifdef ENABLE_FOLD_CHECKING
13546 htab_t ht;
13560 #endif
13564 #ifdef ENABLE_FOLD_CHECKING
13581 #endif
13583 }
13585 /* Perform constant folding and related simplification of initializer
13586 expression EXPR. These behave identically to "fold_buildN" but ignore
13587 potential run-time traps and exceptions that fold must preserve. */
13589 #define START_FOLD_INIT \
13590 int saved_signaling_nans = flag_signaling_nans;\
13591 int saved_trapping_math = flag_trapping_math;\
13592 int saved_rounding_math = flag_rounding_math;\
13593 int saved_trapv = flag_trapv;\
13594 int saved_folding_initializer = folding_initializer;\
13595 flag_signaling_nans = 0;\
13596 flag_trapping_math = 0;\
13597 flag_rounding_math = 0;\
13598 flag_trapv = 0;\
13599 folding_initializer = 1;
13601 #define END_FOLD_INIT \
13602 flag_signaling_nans = saved_signaling_nans;\
13603 flag_trapping_math = saved_trapping_math;\
13604 flag_rounding_math = saved_rounding_math;\
13605 flag_trapv = saved_trapv;\
13606 folding_initializer = saved_folding_initializer;
13608 tree
13610 {
13611 tree result;
13612 START_FOLD_INIT;
13616 END_FOLD_INIT;
13618 }
13620 tree
13622 {
13623 tree result;
13624 START_FOLD_INIT;
13628 END_FOLD_INIT;
13630 }
13632 tree
13634 tree op2)
13635 {
13636 tree result;
13637 START_FOLD_INIT;
13641 END_FOLD_INIT;
13643 }
13645 tree
13648 {
13649 tree result;
13650 START_FOLD_INIT;
13654 END_FOLD_INIT;
13656 }
13658 #undef START_FOLD_INIT
13659 #undef END_FOLD_INIT
13661 /* Determine if first argument is a multiple of second argument. Return 0 if
13662 it is not, or we cannot easily determined it to be.
13664 An example of the sort of thing we care about (at this point; this routine
13665 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13666 fold cases do now) is discovering that
13668 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13670 is a multiple of
13672 SAVE_EXPR (J * 8)
13674 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13676 This code also handles discovering that
13678 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13680 is a multiple of 8 so we don't have to worry about dealing with a
13681 possible remainder.
13683 Note that we *look* inside a SAVE_EXPR only to determine how it was
13684 calculated; it is not safe for fold to do much of anything else with the
13685 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13686 at run time. For example, the latter example above *cannot* be implemented
13687 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13688 evaluation time of the original SAVE_EXPR is not necessarily the same at
13689 the time the new expression is evaluated. The only optimization of this
13690 sort that would be valid is changing
13692 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13694 divided by 8 to
13696 SAVE_EXPR (I) * SAVE_EXPR (J)
13698 (where the same SAVE_EXPR (J) is used in the original and the
13699 transformed version). */
13701 int
13703 {
13711 {
13713 /* Bitwise and provides a power of two multiple. If the mask is
13714 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13717 /* FALLTHRU */
13730 {
13734 /* const_binop may not detect overflow correctly,
13735 so check for it explicitly here. */
13741 size_one_node,
13745 }
13749 /* Can't handle conversions from non-integral or wider integral type. */
13755 /* .. fall through ... */
13772 }
13773 }
13775 /* Return true if CODE or TYPE is known to be non-negative. */
13777 static bool
13779 {
13782 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13783 have a signed:1 type (where the value is -1 and 0). */
13786 }
13788 /* Return true if (CODE OP0) is known to be non-negative. If the return
13789 value is based on the assumption that signed overflow is undefined,
13790 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13791 *STRICT_OVERFLOW_P. */
13793 bool
13796 {
13801 {
13803 /* We can't return 1 if flag_wrapv is set because
13804 ABS_EXPR<INT_MIN> = INT_MIN. */
13808 {
13811 }
13818 strict_overflow_p);
13821 {
13826 {
13829 strict_overflow_p);
13831 {
13835 strict_overflow_p);
13836 }
13837 }
13839 {
13842 strict_overflow_p);
13846 }
13847 }
13852 }
13854 /* We don't know sign of `t', so be conservative and return false. */
13856 }
13858 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13859 value is based on the assumption that signed overflow is undefined,
13860 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13861 *STRICT_OVERFLOW_P. */
13863 bool
13866 {
13871 {
13876 strict_overflow_p)
13878 strict_overflow_p));
13880 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13881 both unsigned and at least 2 bits shorter than the result. */
13885 {
13890 {
13894 }
13895 }
13900 {
13901 /* x * x for floating point x is always non-negative. */
13905 strict_overflow_p)
13907 strict_overflow_p));
13908 }
13910 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
13911 both unsigned and their total bits is shorter than the result. */
13915 {
13922 }
13928 strict_overflow_p)
13930 strict_overflow_p));
13941 strict_overflow_p)
13943 strict_overflow_p));
13950 strict_overflow_p);
13953 }
13955 /* We don't know sign of `t', so be conservative and return false. */
13957 }
13959 /* Return true if T is known to be non-negative. If the return
13960 value is based on the assumption that signed overflow is undefined,
13961 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13962 *STRICT_OVERFLOW_P. */
13964 bool
13966 {
13971 {
13973 /* Query VRP to see if it has recorded any information about
13974 the range of this object. */
13988 strict_overflow_p)
13990 strict_overflow_p));
13994 }
13995 /* We don't know sign of `t', so be conservative and return false. */
13997 }
13999 /* Return true if T is known to be non-negative. If the return
14000 value is based on the assumption that signed overflow is undefined,
14001 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14002 *STRICT_OVERFLOW_P. */
14004 bool
14006 {
14012 {
14014 {
14018 /* If the initializer is non-void, then it's a normal expression
14019 that will be assigned to the slot. */
14023 /* Otherwise, the initializer sets the slot in some way. One common
14024 way is an assignment statement at the end of the initializer. */
14026 {
14034 else
14036 }
14041 strict_overflow_p);
14044 }
14047 {
14051 {
14069 /* Always true. */
14073 /* sqrt(-0.0) is -0.0. */
14077 strict_overflow_p);
14110 /* True if the 1st argument is nonnegative. */
14112 strict_overflow_p);
14115 /* True if the 1st OR 2nd arguments are nonnegative. */
14117 strict_overflow_p)
14119 strict_overflow_p)));
14122 /* True if the 1st AND 2nd arguments are nonnegative. */
14124 strict_overflow_p)
14126 strict_overflow_p)));
14129 /* True if the 2nd argument is nonnegative. */
14131 strict_overflow_p);
14134 /* True if the 1st argument is nonnegative or the second
14135 argument is an even integer. */
14137 {
14141 }
14143 strict_overflow_p);
14146 /* True if the 1st argument is nonnegative or the second
14147 argument is an even integer valued real. */
14149 {
14150 REAL_VALUE_TYPE c;
14151 HOST_WIDE_INT n;
14156 {
14157 REAL_VALUE_TYPE cint;
14162 }
14163 }
14165 strict_overflow_p);
14169 }
14172 }
14179 strict_overflow_p);
14182 strict_overflow_p);
14185 strict_overflow_p);
14190 }
14192 /* We don't know sign of `t', so be conservative and return false. */
14194 }
14196 /* Return true if T is known to be non-negative. If the return
14197 value is based on the assumption that signed overflow is undefined,
14198 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14199 *STRICT_OVERFLOW_P. */
14201 bool
14203 {
14210 {
14217 strict_overflow_p);
14223 strict_overflow_p);
14232 }
14235 {
14243 strict_overflow_p);
14248 strict_overflow_p);
14263 }
14264 }
14266 /* Return true if `t' is known to be non-negative. Handle warnings
14267 about undefined signed overflow. */
14269 bool
14271 {
14278 "determining that expression is always "
14280 WARN_STRICT_OVERFLOW_MISC);
14282 }
14285 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14286 For floating point we further ensure that T is not denormal.
14287 Similar logic is present in nonzero_address in rtlanal.h.
14289 If the return value is based on the assumption that signed overflow
14290 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14291 change *STRICT_OVERFLOW_P. */
14293 bool
14296 {
14298 {
14301 strict_overflow_p);
14304 {
14310 strict_overflow_p));
14311 }
14316 strict_overflow_p);
14320 }
14323 }
14325 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14326 For floating point we further ensure that T is not denormal.
14327 Similar logic is present in nonzero_address in rtlanal.h.
14329 If the return value is based on the assumption that signed overflow
14330 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14331 change *STRICT_OVERFLOW_P. */
14333 bool
14335 tree type,
14336 tree op0,
14338 {
14341 {
14345 {
14346 /* With the presence of negative values it is hard
14347 to say something. */
14354 /* One of operands must be positive and the other non-negative. */
14355 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14356 overflows, on a twos-complement machine the sum of two
14357 nonnegative numbers can never be zero. */
14359 strict_overflow_p)
14361 strict_overflow_p));
14362 }
14367 {
14369 strict_overflow_p)
14371 strict_overflow_p))
14372 {
14375 }
14376 }
14385 {
14388 }
14395 {
14399 /* When both operands are nonzero, then MAX must be too. */
14401 strict_overflow_p))
14404 /* MAX where operand 0 is positive is positive. */
14406 strict_overflow_p);
14407 }
14408 /* MAX where operand 1 is positive is positive. */
14413 {
14417 }
14422 strict_overflow_p)
14424 strict_overflow_p));
14428 }
14431 }
14433 /* Return true when T is an address and is known to be nonzero.
14434 For floating point we further ensure that T is not denormal.
14435 Similar logic is present in nonzero_address in rtlanal.h.
14437 If the return value is based on the assumption that signed overflow
14438 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14439 change *STRICT_OVERFLOW_P. */
14441 bool
14443 {
14446 {
14448 /* Query VRP to see if it has recorded any information about
14449 the range of this object. */
14456 {
14462 /* Weak declarations may link to NULL. */
14466 /* Constants are never weak. */
14471 }
14479 {
14483 }
14488 }
14490 }
14492 /* Return true when T is an address and is known to be nonzero.
14493 For floating point we further ensure that T is not denormal.
14494 Similar logic is present in nonzero_address in rtlanal.h.
14496 If the return value is based on the assumption that signed overflow
14497 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14498 change *STRICT_OVERFLOW_P. */
14500 bool
14502 {
14506 /* Doing something useful for floating point would need more work. */
14512 {
14515 strict_overflow_p);
14521 strict_overflow_p);
14529 }
14532 {
14535 strict_overflow_p);
14543 strict_overflow_p);
14561 strict_overflow_p);
14565 strict_overflow_p);
14572 }
14574 }
14576 /* Return true when T is an address and is known to be nonzero.
14577 Handle warnings about undefined signed overflow. */
14579 bool
14581 {
14588 "determining that expression is always "
14590 WARN_STRICT_OVERFLOW_MISC);
14592 }
14594 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14595 attempt to fold the expression to a constant without modifying TYPE,
14596 OP0 or OP1.
14598 If the expression could be simplified to a constant, then return
14599 the constant. If the expression would not be simplified to a
14600 constant, then return NULL_TREE. */
14602 tree
14604 {
14607 }
14609 /* Given the components of a unary expression CODE, TYPE and OP0,
14610 attempt to fold the expression to a constant without modifying
14611 TYPE or OP0.
14613 If the expression could be simplified to a constant, then return
14614 the constant. If the expression would not be simplified to a
14615 constant, then return NULL_TREE. */
14617 tree
14619 {
14622 }
14624 /* If EXP represents referencing an element in a constant string
14625 (either via pointer arithmetic or array indexing), return the
14626 tree representing the value accessed, otherwise return NULL. */
14628 tree
14630 {
14634 {
14636 tree index;
14637 tree string;
14641 else
14642 {
14646 /* Optimize the special-case of a zero lower bound.
14648 We convert the low_bound to sizetype to avoid some problems
14649 with constant folding. (E.g. suppose the lower bound is 1,
14650 and its mode is QI. Without the conversion,l (ARRAY
14651 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14652 +INDEX), which becomes (ARRAY+255+INDEX). Opps!) */
14657 }
14670 }
14672 }
14674 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14675 an integer constant, real, or fixed-point constant.
14677 TYPE is the type of the result. */
14679 static tree
14681 {
14685 {
14687 {
14689 HOST_WIDE_INT high;
14697 }
14704 {
14705 FIXED_VALUE_TYPE f;
14710 /* Propagate overflow flags. */
14712 {
14715 }
14719 }
14723 }
14726 }
14728 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14729 an integer constant or real constant.
14731 TYPE is the type of the result. */
14733 tree
14735 {
14739 {
14741 /* If the value is unsigned, then the absolute value is
14742 the same as the ordinary value. */
14745 /* Similarly, if the value is non-negative. */
14748 /* If the value is negative, then the absolute value is
14749 its negation. */
14750 else
14751 {
14753 HOST_WIDE_INT high;
14759 }
14765 else
14771 }
14774 }
14776 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14777 constant. TYPE is the type of the result. */
14779 static tree
14781 {
14791 }
14793 /* Given CODE, a relational operator, the target type, TYPE and two
14794 constant operands OP0 and OP1, return the result of the
14795 relational operation. If the result is not a compile time
14796 constant, then return NULL_TREE. */
14798 static tree
14800 {
14803 /* From here on, the only cases we handle are when the result is
14804 known to be a constant. */
14807 {
14811 /* Handle the cases where either operand is a NaN. */
14813 {
14815 {
14843 }
14846 }
14849 }
14852 {
14856 }
14858 /* Handle equality/inequality of complex constants. */
14860 {
14871 else
14873 }
14875 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14877 To compute GT, swap the arguments and do LT.
14878 To compute GE, do LT and invert the result.
14879 To compute LE, swap the arguments, do LT and invert the result.
14880 To compute NE, do EQ and invert the result.
14882 Therefore, the code below must handle only EQ and LT. */
14885 {
14890 }
14892 /* Note that it is safe to invert for real values here because we
14893 have already handled the one case that it matters. */
14897 {
14900 }
14902 /* Compute a result for LT or EQ if args permit;
14903 Otherwise return T. */
14905 {
14910 else
14912 }
14913 else
14919 }
14921 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14922 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14923 itself. */
14925 tree
14927 {
14928 /* If the expression does not have side effects then we don't have to wrap
14929 it with a cleanup point expression. */
14933 /* If the expression is a return, check to see if the expression inside the
14934 return has no side effects or the right hand side of the modify expression
14935 inside the return. If either don't have side effects set we don't need to
14936 wrap the expression in a cleanup point expression. Note we don't check the
14937 left hand side of the modify because it should always be a return decl. */
14939 {
14946 }
14949 }
14951 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14952 of an indirection through OP0, or NULL_TREE if no simplification is
14953 possible. */
14955 tree
14957 {
14959 tree subtype;
14967 {
14970 /* *&CONST_DECL -> to the value of the const decl. */
14973 /* *&p => p; make sure to handle *&"str"[cst] here. */
14975 {
14979 else
14981 }
14982 /* *(foo *)&fooarray => fooarray[0] */
14985 {
14991 }
14992 /* *(foo *)&complexfoo => __real__ complexfoo */
14996 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14999 {
15003 }
15004 }
15006 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15009 {
15012 tree op00type;
15019 {
15030 }
15031 }
15034 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15037 {
15040 tree op00type;
15047 {
15051 }
15052 }
15054 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15057 {
15058 tree type_domain;
15065 }
15068 }
15070 /* Builds an expression for an indirection through T, simplifying some
15071 cases. */
15073 tree
15075 {
15081 else
15083 }
15085 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15087 tree
15089 {
15094 else
15096 }
15098 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15099 whose result is ignored. The type of the returned tree need not be
15100 the same as the original expression. */
15102 tree
15104 {
15110 {
15121 else
15127 {
15143 }
15148 }
15149 }
15151 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15152 This can only be applied to objects of a sizetype. */
15154 tree
15156 {
15163 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15164 have to do anything. Only do this when we are not given a const,
15165 because in that case, this check is more expensive than just
15166 doing it. */
15168 {
15173 }
15175 /* If divisor is a power of two, simplify this to bit manipulation. */
15177 {
15179 {
15192 {
15193 high++;
15196 }
15200 }
15201 else
15202 {
15203 tree t;
15209 }
15210 }
15211 else
15212 {
15217 }
15220 }
15222 /* Likewise, but round down. */
15224 tree
15226 {
15233 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15234 have to do anything. Only do this when we are not given a const,
15235 because in that case, this check is more expensive than just
15236 doing it. */
15238 {
15243 }
15245 /* If divisor is a power of two, simplify this to bit manipulation. */
15247 {
15248 tree t;
15252 }
15253 else
15254 {
15259 }
15262 }
15264 /* Returns the pointer to the base of the object addressed by EXP and
15265 extracts the information about the offset of the access, storing it
15266 to PBITPOS and POFFSET. */
15268 static tree
15271 {
15272 tree core;
15275 HOST_WIDE_INT bitsize;
15278 {
15283 }
15284 else
15285 {
15289 }
15292 }
15294 /* Returns true if addresses of E1 and E2 differ by a constant, false
15295 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15297 bool
15299 {
15313 {
15323 }
15325 {
15326 /* If only one of the offsets is non-constant, the difference cannot
15327 be a constant. */
15329 }
15330 else
15335 }
15337 /* Simplify the floating point expression EXP when the sign of the
15338 result is not significant. Return NULL_TREE if no simplification
15339 is possible. */
15341 tree
15343 {
15347 {
15382 {
15385 {
15387 /* Strip copysign function call, return the 1st argument. */
15393 /* Strip sign ops from the argument of "odd" math functions. */
15395 {
15399 }
15401 }
15402 }
15407 }
15409 }