| blob | e1e04bb625da9b11ed9fa363c002a31833c5a55a |
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, 2008
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 {
1016 {
1019 {
1022 }
1023 }
1026 }
1027 \f
1028 /* Return true if the built-in mathematical function specified by CODE
1029 is odd, i.e. -f(x) == f(-x). */
1031 static bool
1033 {
1035 {
1069 }
1071 }
1073 /* Check whether we may negate an integer constant T without causing
1074 overflow. */
1076 bool
1078 {
1081 tree type;
1091 {
1096 }
1097 else
1102 }
1104 /* Determine whether an expression T can be cheaply negated using
1105 the function negate_expr without introducing undefined overflow. */
1107 static bool
1109 {
1110 tree type;
1119 {
1124 /* Check that -CST will not overflow type. */
1150 /* -(A + B) -> (-B) - A. */
1155 /* -(A + B) -> (-A) - B. */
1159 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
1169 /* Fall through. */
1182 /* In general we can't negate A / B, because if A is INT_MIN and
1183 B is 1, we may turn this into INT_MIN / -1 which is undefined
1184 and actually traps on some architectures. But if overflow is
1185 undefined, we can negate, because - (INT_MIN / 1) is an
1186 overflow. */
1194 /* Negate -((double)float) as (double)(-float). */
1196 {
1200 }
1204 /* Negate -f(x) as f(-x). */
1210 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1212 {
1218 }
1223 }
1225 }
1227 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
1228 simplification is possible.
1229 If negate_expr_p would return true for T, NULL_TREE will never be
1230 returned. */
1232 static tree
1234 {
1236 tree tem;
1239 {
1240 /* Convert - (~A) to A + 1. */
1256 /* Two's complement FP formats, such as c4x, may overflow. */
1266 {
1275 }
1297 {
1298 /* -(A + B) -> (-B) - A. */
1302 {
1306 }
1308 /* -(A + B) -> (-A) - B. */
1310 {
1314 }
1315 }
1319 /* - (A - B) -> B - A */
1331 /* Fall through. */
1335 {
1344 }
1352 /* In general we can't negate A / B, because if A is INT_MIN and
1353 B is 1, we may turn this into INT_MIN / -1 which is undefined
1354 and actually traps on some architectures. But if overflow is
1355 undefined, we can negate, because - (INT_MIN / 1) is an
1356 overflow. */
1358 {
1363 {
1370 }
1373 {
1380 }
1381 }
1385 /* Convert -((double)float) into (double)(-float). */
1387 {
1391 }
1395 /* Negate -f(x) as f(-x). */
1398 {
1404 }
1408 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1410 {
1415 {
1422 }
1423 }
1428 }
1431 }
1433 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
1434 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
1435 return NULL_TREE. */
1437 static tree
1439 {
1452 }
1453 \f
1454 /* Split a tree IN into a constant, literal and variable parts that could be
1455 combined with CODE to make IN. "constant" means an expression with
1456 TREE_CONSTANT but that isn't an actual constant. CODE must be a
1457 commutative arithmetic operation. Store the constant part into *CONP,
1458 the literal in *LITP and return the variable part. If a part isn't
1459 present, set it to null. If the tree does not decompose in this way,
1460 return the entire tree as the variable part and the other parts as null.
1462 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
1463 case, we negate an operand that was subtracted. Except if it is a
1464 literal for which we use *MINUS_LITP instead.
1466 If NEGATE_P is true, we are negating all of IN, again except a literal
1467 for which we use *MINUS_LITP instead.
1469 If IN is itself a literal or constant, return it as appropriate.
1471 Note that we do not guarantee that any of the three values will be the
1472 same type as IN, but they will have the same signedness and mode. */
1474 static tree
1477 {
1484 /* Strip any conversions that don't change the machine mode or signedness. */
1493 /* We can associate addition and subtraction together (even
1494 though the C standard doesn't say so) for integers because
1495 the value is not affected. For reals, the value might be
1496 affected, so we can't. */
1499 {
1505 /* First see if either of the operands is a literal, then a constant. */
1518 /* If we haven't dealt with either operand, this is not a case we can
1519 decompose. Otherwise, VAR is either of the ones remaining, if any. */
1524 else
1527 /* Now do any needed negations. */
1534 }
1537 else
1541 {
1548 }
1551 }
1553 /* Re-associate trees split by the above function. T1 and T2 are either
1554 expressions to associate or null. Return the new expression, if any. If
1555 we build an operation, do it in TYPE and with CODE. */
1557 static tree
1559 {
1565 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
1566 try to fold this since we will have infinite recursion. But do
1567 deal with any NEGATE_EXPRs. */
1570 {
1572 {
1581 }
1583 {
1586 }
1590 }
1594 }
1595 \f
1596 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1597 for use in int_const_binop, size_binop and size_diffop. */
1599 static bool
1601 {
1608 {
1617 }
1622 }
1625 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1626 to produce a new constant. Return NULL_TREE if we don't know how
1627 to evaluate CODE at compile-time.
1629 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1631 tree
1633 {
1637 HOST_WIDE_INT hi;
1639 HOST_WIDE_INT garbageh;
1640 tree t;
1643 int is_sizetype
1653 {
1669 /* It's unclear from the C standard whether shifts can overflow.
1670 The following code ignores overflow; perhaps a C standard
1671 interpretation ruling is needed. */
1700 /* This is a shortcut for a common special case. */
1705 {
1711 }
1713 /* ... fall through ... */
1719 {
1722 }
1725 {
1728 }
1735 /* This is a shortcut for a common special case. */
1740 {
1745 }
1747 /* ... fall through ... */
1765 else
1771 else
1777 }
1780 {
1783 /* Propagate overflow flags ourselves. */
1786 {
1789 }
1790 }
1791 else
1797 }
1799 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1800 constant. We assume ARG1 and ARG2 have the same data type, or at least
1801 are the same kind of constant and the same machine mode. Return zero if
1802 combining the constants is not allowed in the current operating mode.
1804 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1806 static tree
1808 {
1809 /* Sanity check for the recursive cases. */
1820 {
1822 REAL_VALUE_TYPE d1;
1823 REAL_VALUE_TYPE d2;
1824 REAL_VALUE_TYPE value;
1825 REAL_VALUE_TYPE result;
1829 /* The following codes are handled by real_arithmetic. */
1831 {
1842 }
1850 /* Don't perform operation if we honor signaling NaNs and
1851 either operand is a NaN. */
1856 /* Don't perform operation if it would raise a division
1857 by zero exception. */
1863 /* If either operand is a NaN, just return it. Otherwise, set up
1864 for floating-point trap; we return an overflow. */
1873 /* Don't constant fold this floating point operation if
1874 the result has overflowed and flag_trapping_math. */
1882 /* Don't constant fold this floating point operation if the
1883 result may dependent upon the run-time rounding mode and
1884 flag_rounding_math is set, or if GCC's software emulation
1885 is unable to accurately represent the result. */
1896 }
1899 {
1900 FIXED_VALUE_TYPE f1;
1901 FIXED_VALUE_TYPE f2;
1902 FIXED_VALUE_TYPE result;
1907 /* The following codes are handled by fixed_arithmetic. */
1909 {
1926 }
1933 /* Propagate overflow flags. */
1935 {
1938 }
1942 }
1945 {
1954 {
1965 notrunc);
1969 notrunc);
1973 {
1974 tree magsquared
1978 notrunc);
1979 tree t1
1983 notrunc);
1984 tree t2
1988 notrunc);
1995 }
2000 }
2004 }
2007 }
2009 /* Create a size type INT_CST node with NUMBER sign extended. KIND
2010 indicates which particular sizetype to create. */
2012 tree
2014 {
2016 }
2017 \f
2018 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2019 is a tree code. The type of the result is taken from the operands.
2020 Both must be equivalent integer types, ala int_binop_types_match_p.
2021 If the operands are constant, so is the result. */
2023 tree
2025 {
2034 /* Handle the special case of two integer constants faster. */
2036 {
2037 /* And some specific cases even faster than that. */
2039 {
2044 }
2046 {
2049 }
2051 {
2054 }
2056 /* Handle general case of two integer constants. */
2058 }
2061 }
2063 /* Given two values, either both of sizetype or both of bitsizetype,
2064 compute the difference between the two values. Return the value
2065 in signed type corresponding to the type of the operands. */
2067 tree
2069 {
2071 tree ctype;
2076 /* If the type is already signed, just do the simple thing. */
2084 else
2087 /* If either operand is not a constant, do the conversions to the signed
2088 type and subtract. The hardware will do the right thing with any
2089 overflow in the subtraction. */
2094 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2095 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2096 overflow) and negate (which can't either). Special-case a result
2097 of zero while we're here. */
2102 else
2106 }
2107 \f
2108 /* A subroutine of fold_convert_const handling conversions of an
2109 INTEGER_CST to another integer type. */
2111 static tree
2113 {
2114 tree t;
2116 /* Given an integer constant, make new constant with new type,
2117 appropriately sign-extended or truncated. */
2120 /* Don't set the overflow when
2121 converting from a pointer, */
2123 /* or to a sizetype with same signedness
2124 and the precision is unchanged.
2125 ??? sizetype is always sign-extended,
2126 but its signedness depends on the
2127 frontend. Thus we see spurious overflows
2128 here if we do not check this. */
2143 }
2145 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2146 to an integer type. */
2148 static tree
2150 {
2152 tree t;
2154 /* The following code implements the floating point to integer
2155 conversion rules required by the Java Language Specification,
2156 that IEEE NaNs are mapped to zero and values that overflow
2157 the target precision saturate, i.e. values greater than
2158 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2159 are mapped to INT_MIN. These semantics are allowed by the
2160 C and C++ standards that simply state that the behavior of
2161 FP-to-integer conversion is unspecified upon overflow. */
2164 REAL_VALUE_TYPE r;
2168 {
2175 }
2177 /* If R is NaN, return zero and show we have an overflow. */
2179 {
2183 }
2185 /* See if R is less than the lower bound or greater than the
2186 upper bound. */
2189 {
2193 {
2197 }
2198 }
2201 {
2204 {
2207 {
2211 }
2212 }
2213 }
2221 }
2223 /* A subroutine of fold_convert_const handling conversions of a
2224 FIXED_CST to an integer type. */
2226 static tree
2228 {
2229 tree t;
2233 /* Right shift FIXED_CST to temp by fbit. */
2237 {
2242 /* Left shift temp to temp_trunc by fbit. */
2247 }
2248 else
2249 {
2254 }
2256 /* If FIXED_CST is negative, we need to round the value toward 0.
2257 By checking if the fractional bits are not zero to add 1 to temp. */
2260 {
2261 double_int one;
2265 }
2267 /* Given a fixed-point constant, make new constant with new type,
2268 appropriately sign-extended or truncated. */
2276 }
2278 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2279 to another floating point type. */
2281 static tree
2283 {
2284 REAL_VALUE_TYPE value;
2285 tree t;
2292 }
2294 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2295 to a floating point type. */
2297 static tree
2299 {
2300 REAL_VALUE_TYPE value;
2301 tree t;
2310 }
2312 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2313 to another fixed-point type. */
2315 static tree
2317 {
2318 FIXED_VALUE_TYPE value;
2319 tree t;
2326 /* Propagate overflow flags. */
2328 {
2331 }
2335 }
2337 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2338 to a fixed-point type. */
2340 static tree
2342 {
2343 FIXED_VALUE_TYPE value;
2344 tree t;
2353 /* Propagate overflow flags. */
2355 {
2358 }
2362 }
2364 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2365 to a fixed-point type. */
2367 static tree
2369 {
2370 FIXED_VALUE_TYPE value;
2371 tree t;
2379 /* Propagate overflow flags. */
2381 {
2384 }
2388 }
2390 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2391 type TYPE. If no simplification can be done return NULL_TREE. */
2393 static tree
2395 {
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 /* Check equality of integer constants before bailing out due to
3031 precision differences. */
3035 /* If both types don't have the same signedness, then we can't consider
3036 them equal. We must check this before the STRIP_NOPS calls
3037 because they may change the signedness of the arguments. As pointers
3038 strictly don't have a signedness, require either two pointers or
3039 two non-pointers as well. */
3044 /* If both types don't have the same precision, then it is not safe
3045 to strip NOPs. */
3052 /* In case both args are comparisons but with different comparison
3053 code, try to swap the comparison operands of one arg to produce
3054 a match and compare that variant. */
3058 {
3066 }
3069 /* This is needed for conversions and for COMPONENT_REF.
3070 Might as well play it safe and always test this. */
3076 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3077 We don't care about side effects in that case because the SAVE_EXPR
3078 takes care of that for us. In all other cases, two expressions are
3079 equal if they have no side effects. If we have two identical
3080 expressions with side effects that should be treated the same due
3081 to the only side effects being identical SAVE_EXPR's, that will
3082 be detected in the recursive calls below. */
3088 /* Next handle constant cases, those for which we can return 1 even
3089 if ONLY_CONST is set. */
3092 {
3107 {
3108 /* If we do not distinguish between signed and unsigned zero,
3109 consider them equal. */
3112 }
3116 {
3122 {
3124 flags))
3128 }
3131 }
3135 flags)
3137 flags));
3150 }
3155 /* Define macros to test an operand from arg0 and arg1 for equality and a
3156 variant that allows null and views null as being different from any
3157 non-null value. In the latter case, if either is null, the both
3158 must be; otherwise, do the normal comparison. */
3159 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3160 TREE_OPERAND (arg1, N), flags)
3162 #define OP_SAME_WITH_NULL(N) \
3163 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3164 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3167 {
3169 /* Two conversions are equal only if signedness and modes match. */
3171 {
3172 CASE_CONVERT:
3180 }
3190 /* For commutative ops, allow the other order. */
3198 /* If either of the pointer (or reference) expressions we are
3199 dereferencing contain a side effect, these cannot be equal. */
3205 {
3215 /* Operands 2 and 3 may be null.
3216 Compare the array index by value if it is constant first as we
3217 may have different types but same value here. */
3226 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3227 may be NULL when we're called to compare MEM_EXPRs. */
3237 }
3241 {
3256 /* Otherwise take into account this is a commutative operation. */
3267 }
3271 {
3273 /* If the CALL_EXPRs call different functions, then they
3274 clearly can not be equal. */
3276 flags))
3279 {
3283 else
3287 }
3289 /* Now see if all the arguments are the same. */
3290 {
3301 /* If we get here and both argument lists are exhausted
3302 then the CALL_EXPRs are equal. */
3304 }
3307 }
3310 /* Consider __builtin_sqrt equal to sqrt. */
3318 }
3320 #undef OP_SAME
3321 #undef OP_SAME_WITH_NULL
3322 }
3323 \f
3324 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3325 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3327 When in doubt, return 0. */
3329 static int
3331 {
3343 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3344 and see if the inner values are the same. This removes any
3345 signedness comparison, which doesn't matter here. */
3352 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3353 actual comparison operand, ARG0.
3355 First throw away any conversions to wider types
3356 already present in the operands. */
3365 {
3368 /* Make sure shorter operand is extended the right way
3369 to match the longer operand. */
3375 }
3378 }
3379 \f
3380 /* See if ARG is an expression that is either a comparison or is performing
3381 arithmetic on comparisons. The comparisons must only be comparing
3382 two different values, which will be stored in *CVAL1 and *CVAL2; if
3383 they are nonzero it means that some operands have already been found.
3384 No variables may be used anywhere else in the expression except in the
3385 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3386 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3388 If this is true, return 1. Otherwise, return zero. */
3390 static int
3392 {
3396 /* We can handle some of the tcc_expression cases here. */
3406 {
3407 /* If we've already found a CVAL1 or CVAL2, this expression is
3408 two complex to handle. */
3414 }
3417 {
3440 /* First see if we can handle the first operand, then the second. For
3441 the second operand, we know *CVAL1 can't be zero. It must be that
3442 one side of the comparison is each of the values; test for the
3443 case where this isn't true by failing if the two operands
3444 are the same. */
3453 ;
3457 ;
3458 else
3462 ;
3466 ;
3467 else
3474 }
3475 }
3476 \f
3477 /* ARG is a tree that is known to contain just arithmetic operations and
3478 comparisons. Evaluate the operations in the tree substituting NEW0 for
3479 any occurrence of OLD0 as an operand of a comparison and likewise for
3480 NEW1 and OLD1. */
3482 static tree
3484 {
3489 /* We can handle some of the tcc_expression cases here. */
3497 {
3512 {
3529 }
3530 /* Fall through - ??? */
3533 {
3537 /* We need to check both for exact equality and tree equality. The
3538 former will be true if the operand has a side-effect. In that
3539 case, we know the operand occurred exactly once. */
3552 }
3556 }
3557 }
3558 \f
3559 /* Return a tree for the case when the result of an expression is RESULT
3560 converted to TYPE and OMITTED was previously an operand of the expression
3561 but is now not needed (e.g., we folded OMITTED * 0).
3563 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3564 the conversion of RESULT to TYPE. */
3566 tree
3568 {
3571 /* If the resulting operand is an empty statement, just return the omitted
3572 statement casted to void. */
3580 }
3582 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3584 static tree
3586 {
3589 /* If the resulting operand is an empty statement, just return the omitted
3590 statement casted to void. */
3598 }
3600 /* Return a tree for the case when the result of an expression is RESULT
3601 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3602 of the expression but are now not needed.
3604 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3605 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3606 evaluated before OMITTED2. Otherwise, if neither has side effects,
3607 just do the conversion of RESULT to TYPE. */
3609 tree
3611 {
3620 }
3622 \f
3623 /* Return a simplified tree node for the truth-negation of ARG. This
3624 never alters ARG itself. We assume that ARG is an operation that
3625 returns a truth value (0 or 1).
3627 FIXME: one would think we would fold the result, but it causes
3628 problems with the dominator optimizer. */
3630 tree
3632 {
3636 /* If this is a comparison, we can simply invert it, except for
3637 floating-point non-equality comparisons, in which case we just
3638 enclose a TRUTH_NOT_EXPR around what we have. */
3641 {
3644 && flag_trapping_math
3648 else
3649 {
3654 else
3657 }
3658 }
3661 {
3676 /* Here we can invert either operand. We invert the first operand
3677 unless the second operand is a TRUTH_NOT_EXPR in which case our
3678 result is the XOR of the first operand with the inside of the
3679 negation of the second operand. */
3684 else
3703 {
3706 /* A COND_EXPR may have a throw as one operand, which
3707 then has void type. Just leave void operands
3708 as they are. */
3714 }
3747 }
3750 }
3752 /* Return a simplified tree node for the truth-negation of ARG. This
3753 never alters ARG itself. We assume that ARG is an operation that
3754 returns a truth value (0 or 1).
3756 FIXME: one would think we would fold the result, but it causes
3757 problems with the dominator optimizer. */
3759 tree
3761 {
3762 tree tem;
3772 }
3774 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3775 operands are another bit-wise operation with a common input. If so,
3776 distribute the bit operations to save an operation and possibly two if
3777 constants are involved. For example, convert
3778 (A | B) & (A | C) into A | (B & C)
3779 Further simplification will occur if B and C are constants.
3781 If this optimization cannot be done, 0 will be returned. */
3783 static tree
3785 {
3786 tree common;
3796 {
3800 }
3802 {
3806 }
3808 {
3812 }
3814 {
3818 }
3819 else
3824 }
3826 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3827 with code CODE. This optimization is unsafe. */
3828 static tree
3830 {
3834 /* (A / C) +- (B / C) -> (A +- B) / C. */
3844 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3849 {
3861 }
3864 }
3865 \f
3866 /* Subroutine for fold_truthop: decode a field reference.
3868 If EXP is a comparison reference, we return the innermost reference.
3870 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3871 set to the starting bit number.
3873 If the innermost field can be completely contained in a mode-sized
3874 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3876 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3877 otherwise it is not changed.
3879 *PUNSIGNEDP is set to the signedness of the field.
3881 *PMASK is set to the mask used. This is either contained in a
3882 BIT_AND_EXPR or derived from the width of the field.
3884 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3886 Return 0 if this is not a component reference or is one that we can't
3887 do anything with. */
3889 static tree
3894 {
3898 tree unsigned_type;
3901 /* All the optimizations using this function assume integer fields.
3902 There are problems with FP fields since the type_for_size call
3903 below can fail for, e.g., XFmode. */
3907 /* We are interested in the bare arrangement of bits, so strip everything
3908 that doesn't affect the machine mode. However, record the type of the
3909 outermost expression if it may matter below. */
3916 {
3922 }
3931 /* If the number of bits in the reference is the same as the bitsize of
3932 the outer type, then the outer type gives the signedness. Otherwise
3933 (in case of a small bitfield) the signedness is unchanged. */
3937 /* Compute the mask to access the bitfield. */
3946 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3954 }
3956 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3957 represents the sign bit of EXP's type. If EXP represents a sign
3958 or zero extension, also test VAL against the unextended type.
3959 The return value is the (sub)expression whose sign bit is VAL,
3960 or NULL_TREE otherwise. */
3962 static tree
3964 {
3968 tree t;
3970 /* Tree EXP must have an integral type. */
3975 /* Tree VAL must be an integer constant. */
3982 {
3989 }
3990 else
3991 {
3998 }
4000 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
4001 treat VAL as if it were unsigned. */
4006 /* Handle extension from a narrower type. */
4012 }
4014 /* Subroutine for fold_truthop: determine if an operand is simple enough
4015 to be evaluated unconditionally. */
4017 static int
4019 {
4020 /* Strip any conversions that don't change the machine mode. */
4029 /* Don't regard global variables as simple. They may be
4030 allocated in ways unknown to the compiler (shared memory,
4031 #pragma weak, etc). */
4034 /* Loading a static variable is unduly expensive, but global
4035 registers aren't expensive. */
4037 }
4038 \f
4039 /* The following functions are subroutines to fold_range_test and allow it to
4040 try to change a logical combination of comparisons into a range test.
4042 For example, both
4043 X == 2 || X == 3 || X == 4 || X == 5
4044 and
4045 X >= 2 && X <= 5
4046 are converted to
4047 (unsigned) (X - 2) <= 3
4049 We describe each set of comparisons as being either inside or outside
4050 a range, using a variable named like IN_P, and then describe the
4051 range with a lower and upper bound. If one of the bounds is omitted,
4052 it represents either the highest or lowest value of the type.
4054 In the comments below, we represent a range by two numbers in brackets
4055 preceded by a "+" to designate being inside that range, or a "-" to
4056 designate being outside that range, so the condition can be inverted by
4057 flipping the prefix. An omitted bound is represented by a "-". For
4058 example, "- [-, 10]" means being outside the range starting at the lowest
4059 possible value and ending at 10, in other words, being greater than 10.
4060 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4061 always false.
4063 We set up things so that the missing bounds are handled in a consistent
4064 manner so neither a missing bound nor "true" and "false" need to be
4065 handled using a special case. */
4067 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4068 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4069 and UPPER1_P are nonzero if the respective argument is an upper bound
4070 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4071 must be specified for a comparison. ARG1 will be converted to ARG0's
4072 type if both are specified. */
4074 static tree
4077 {
4078 tree tem;
4082 /* If neither arg represents infinity, do the normal operation.
4083 Else, if not a comparison, return infinity. Else handle the special
4084 comparison rules. Note that most of the cases below won't occur, but
4085 are handled for consistency. */
4088 {
4093 }
4098 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4099 for neither. In real maths, we cannot assume open ended ranges are
4100 the same. But, this is computer arithmetic, where numbers are finite.
4101 We can therefore make the transformation of any unbounded range with
4102 the value Z, Z being greater than any representable number. This permits
4103 us to treat unbounded ranges as equal. */
4107 {
4128 }
4131 }
4132 \f
4133 /* Given EXP, a logical expression, set the range it is testing into
4134 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4135 actually being tested. *PLOW and *PHIGH will be made of the same
4136 type as the returned expression. If EXP is not a comparison, we
4137 will most likely not be returning a useful value and range. Set
4138 *STRICT_OVERFLOW_P to true if the return value is only valid
4139 because signed overflow is undefined; otherwise, do not change
4140 *STRICT_OVERFLOW_P. */
4142 static tree
4145 {
4152 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4153 and see if we can refine the range. Some of the cases below may not
4154 happen, but it doesn't seem worth worrying about this. We "continue"
4155 the outer loop when we've changed something; otherwise we "break"
4156 the switch, which will "break" the while. */
4162 {
4167 {
4179 }
4182 {
4189 /* We can only do something if the range is testing for zero
4190 and if the second operand is an integer constant. Note that
4191 saying something is "in" the range we make is done by
4192 complementing IN_P since it will set in the initial case of
4193 being not equal to zero; "out" is leaving it alone. */
4200 {
4221 }
4223 /* If this is an unsigned comparison, we also know that EXP is
4224 greater than or equal to zero. We base the range tests we make
4225 on that fact, so we record it here so we can parse existing
4226 range tests. We test arg0_type since often the return type
4227 of, e.g. EQ_EXPR, is boolean. */
4229 {
4233 NULL_TREE))
4238 /* If the high bound is missing, but we have a nonzero low
4239 bound, reverse the range so it goes from zero to the low bound
4240 minus 1. */
4242 {
4247 }
4248 }
4254 /* (-x) IN [a,b] -> x in [-b, -a] */
4266 /* ~ X -> -X - 1 */
4275 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4276 move a constant to the other side. */
4281 /* If EXP is signed, any overflow in the computation is undefined,
4282 so we don't worry about it so long as our computations on
4283 the bounds don't overflow. For unsigned, overflow is defined
4284 and this is exactly the right thing. */
4296 /* Check for an unsigned range which has wrapped around the maximum
4297 value thus making n_high < n_low, and normalize it. */
4299 {
4305 /* If the range is of the form +/- [ x+1, x ], we won't
4306 be able to normalize it. But then, it represents the
4307 whole range or the empty set, so make it
4308 +/- [ -, - ]. */
4312 else
4314 }
4315 else
4339 /* If we're converting arg0 from an unsigned type, to exp,
4340 a signed type, we will be doing the comparison as unsigned.
4341 The tests above have already verified that LOW and HIGH
4342 are both positive.
4344 So we have to ensure that we will handle large unsigned
4345 values the same way that the current signed bounds treat
4346 negative values. */
4349 {
4350 tree high_positive;
4351 tree equiv_type;
4352 /* For fixed-point modes, we need to pass the saturating flag
4353 as the 2nd parameter. */
4358 else
4362 /* A range without an upper bound is, naturally, unbounded.
4363 Since convert would have cropped a very large value, use
4364 the max value for the destination type. */
4365 high_positive
4372 high_positive),
4375 /* If the low bound is specified, "and" the range with the
4376 range for which the original unsigned value will be
4377 positive. */
4379 {
4383 integer_zero_node),
4384 high_positive))
4388 }
4389 else
4390 {
4391 /* Otherwise, "or" the range with the range of the input
4392 that will be interpreted as negative. */
4396 integer_zero_node),
4397 high_positive))
4401 }
4402 }
4410 }
4413 }
4415 /* If EXP is a constant, we can evaluate whether this is true or false. */
4417 {
4424 }
4428 }
4429 \f
4430 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4431 type, TYPE, return an expression to test if EXP is in (or out of, depending
4432 on IN_P) the range. Return 0 if the test couldn't be created. */
4434 static tree
4436 {
4438 tree value;
4440 #ifdef HAVE_canonicalize_funcptr_for_compare
4441 /* Disable this optimization for function pointer expressions
4442 on targets that require function pointer canonicalization. */
4447 #endif
4450 {
4456 }
4474 {
4476 {
4480 }
4482 }
4484 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4486 {
4488 HOST_WIDE_INT hi;
4493 {
4496 }
4497 else
4498 {
4501 }
4504 {
4506 {
4509 }
4512 }
4513 }
4515 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4516 This requires wrap-around arithmetics for the type of the expression. */
4518 {
4520 /* There is no requirement that LOW be within the range of ETYPE
4521 if the latter is a subtype. It must, however, be within the base
4522 type of ETYPE. So be sure we do the subtraction in that type. */
4535 }
4537 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4540 {
4543 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4544 for the type in question, as we rely on this here. */
4554 else
4556 }
4566 {
4568 {
4574 }
4576 }
4584 }
4585 \f
4586 /* Return the predecessor of VAL in its type, handling the infinite case. */
4588 static tree
4590 {
4596 else
4598 }
4600 /* Return the successor of VAL in its type, handling the infinite case. */
4602 static tree
4604 {
4610 else
4612 }
4614 /* Given two ranges, see if we can merge them into one. Return 1 if we
4615 can, 0 if we can't. Set the output range into the specified parameters. */
4617 static int
4620 {
4624 tree tem;
4634 /* Make range 0 be the range that starts first, or ends last if they
4635 start at the same value. Swap them if it isn't. */
4638 || (lowequal
4641 {
4645 }
4647 /* Now flag two cases, whether the ranges are disjoint or whether the
4648 second range is totally subsumed in the first. Note that the tests
4649 below are simplified by the ones above. */
4655 /* We now have four cases, depending on whether we are including or
4656 excluding the two ranges. */
4658 {
4659 /* If they don't overlap, the result is false. If the second range
4660 is a subset it is the result. Otherwise, the range is from the start
4661 of the second to the end of the first. */
4666 else
4668 }
4671 {
4672 /* If they don't overlap, the result is the first range. If they are
4673 equal, the result is false. If the second range is a subset of the
4674 first, and the ranges begin at the same place, we go from just after
4675 the end of the second range to the end of the first. If the second
4676 range is not a subset of the first, or if it is a subset and both
4677 ranges end at the same place, the range starts at the start of the
4678 first range and ends just before the second range.
4679 Otherwise, we can't describe this as a single range. */
4685 {
4690 {
4691 /* We are in the weird situation where high0 > high1 but
4692 high1 has no successor. Punt. */
4694 }
4695 }
4697 {
4702 {
4703 /* low0 < low1 but low1 has no predecessor. Punt. */
4705 }
4706 }
4707 else
4709 }
4712 {
4713 /* If they don't overlap, the result is the second range. If the second
4714 is a subset of the first, the result is false. Otherwise,
4715 the range starts just after the first range and ends at the
4716 end of the second. */
4721 else
4722 {
4727 {
4728 /* high1 > high0 but high0 has no successor. Punt. */
4730 }
4731 }
4732 }
4734 else
4735 {
4736 /* The case where we are excluding both ranges. Here the complex case
4737 is if they don't overlap. In that case, the only time we have a
4738 range is if they are adjacent. If the second is a subset of the
4739 first, the result is the first. Otherwise, the range to exclude
4740 starts at the beginning of the first range and ends at the end of the
4741 second. */
4743 {
4748 else
4749 {
4750 /* Canonicalize - [min, x] into - [-, x]. */
4753 {
4758 /* FALLTHROUGH */
4771 }
4773 /* Canonicalize - [x, max] into - [x, -]. */
4776 {
4781 /* FALLTHROUGH */
4796 }
4798 /* The ranges might be also adjacent between the maximum and
4799 minimum values of the given type. For
4800 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4801 return + [x + 1, y - 1]. */
4803 {
4810 }
4811 else
4813 }
4814 }
4817 else
4819 }
4823 }
4824 \f
4826 /* Subroutine of fold, looking inside expressions of the form
4827 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4828 of the COND_EXPR. This function is being used also to optimize
4829 A op B ? C : A, by reversing the comparison first.
4831 Return a folded expression whose code is not a COND_EXPR
4832 anymore, or NULL_TREE if no folding opportunity is found. */
4834 static tree
4836 {
4841 tree tem;
4846 /* If we have A op 0 ? A : -A, consider applying the following
4847 transformations:
4849 A == 0? A : -A same as -A
4850 A != 0? A : -A same as A
4851 A >= 0? A : -A same as abs (A)
4852 A > 0? A : -A same as abs (A)
4853 A <= 0? A : -A same as -abs (A)
4854 A < 0? A : -A same as -abs (A)
4856 None of these transformations work for modes with signed
4857 zeros. If A is +/-0, the first two transformations will
4858 change the sign of the result (from +0 to -0, or vice
4859 versa). The last four will fix the sign of the result,
4860 even though the original expressions could be positive or
4861 negative, depending on the sign of A.
4863 Note that all these transformations are correct if A is
4864 NaN, since the two alternatives (A and -A) are also NaNs. */
4871 /* In the case that A is of the form X-Y, '-A' (arg2) may
4872 have already been folded to Y-X, check for that. */
4880 {
4892 /* Fall through. */
4914 }
4916 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4917 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4918 both transformations are correct when A is NaN: A != 0
4919 is then true, and A == 0 is false. */
4923 {
4928 }
4930 /* Try some transformations of A op B ? A : B.
4932 A == B? A : B same as B
4933 A != B? A : B same as A
4934 A >= B? A : B same as max (A, B)
4935 A > B? A : B same as max (B, A)
4936 A <= B? A : B same as min (A, B)
4937 A < B? A : B same as min (B, A)
4939 As above, these transformations don't work in the presence
4940 of signed zeros. For example, if A and B are zeros of
4941 opposite sign, the first two transformations will change
4942 the sign of the result. In the last four, the original
4943 expressions give different results for (A=+0, B=-0) and
4944 (A=-0, B=+0), but the transformed expressions do not.
4946 The first two transformations are correct if either A or B
4947 is a NaN. In the first transformation, the condition will
4948 be false, and B will indeed be chosen. In the case of the
4949 second transformation, the condition A != B will be true,
4950 and A will be chosen.
4952 The conversions to max() and min() are not correct if B is
4953 a number and A is not. The conditions in the original
4954 expressions will be false, so all four give B. The min()
4955 and max() versions would give a NaN instead. */
4958 /* Avoid these transformations if the COND_EXPR may be used
4959 as an lvalue in the C++ front-end. PR c++/19199. */
4960 && (in_gimple_form
4965 {
4970 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4972 {
4976 }
4979 {
4988 /* In C++ a ?: expression can be an lvalue, so put the
4989 operand which will be used if they are equal first
4990 so that we can convert this back to the
4991 corresponding COND_EXPR. */
4993 {
5000 }
5007 {
5014 }
5027 }
5028 }
5030 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5031 we might still be able to simplify this. For example,
5032 if C1 is one less or one more than C2, this might have started
5033 out as a MIN or MAX and been transformed by this function.
5034 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5040 {
5042 /* We can replace A with C1 in this case. */
5047 /* If C1 is C2 + 1, this is min(A, C2). */
5049 OEP_ONLY_CONST)
5053 OEP_ONLY_CONST))
5055 type,
5057 arg2));
5061 /* If C1 is C2 - 1, this is min(A, C2). */
5063 OEP_ONLY_CONST)
5067 OEP_ONLY_CONST))
5069 type,
5071 arg2));
5075 /* If C1 is C2 - 1, this is max(A, C2). */
5077 OEP_ONLY_CONST)
5081 OEP_ONLY_CONST))
5083 type,
5085 arg2));
5089 /* If C1 is C2 + 1, this is max(A, C2). */
5091 OEP_ONLY_CONST)
5095 OEP_ONLY_CONST))
5097 type,
5099 arg2));
5105 }
5108 }
5111 \f
5112 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5113 #define LOGICAL_OP_NON_SHORT_CIRCUIT (BRANCH_COST >= 2)
5114 #endif
5116 /* EXP is some logical combination of boolean tests. See if we can
5117 merge it into some range test. Return the new tree if so. */
5119 static tree
5121 {
5129 tree tem;
5133 /* If this is an OR operation, invert both sides; we will invert
5134 again at the end. */
5138 /* If both expressions are the same, if we can merge the ranges, and we
5139 can build the range test, return it or it inverted. If one of the
5140 ranges is always true or always false, consider it to be the same
5141 expression as the other. */
5149 {
5153 }
5155 /* On machines where the branch cost is expensive, if this is a
5156 short-circuited branch and the underlying object on both sides
5157 is the same, make a non-short-circuit operation. */
5163 {
5164 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5165 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5166 which cases we can't do this. */
5174 {
5183 {
5186 WARN_STRICT_OVERFLOW_COMPARISON);
5190 }
5191 }
5192 }
5195 }
5196 \f
5197 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5198 bit value. Arrange things so the extra bits will be set to zero if and
5199 only if C is signed-extended to its full width. If MASK is nonzero,
5200 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5202 static tree
5204 {
5207 tree temp;
5212 /* We work by getting just the sign bit into the low-order bit, then
5213 into the high-order bit, then sign-extend. We then XOR that value
5214 with C. */
5218 /* We must use a signed type in order to get an arithmetic right shift.
5219 However, we must also avoid introducing accidental overflows, so that
5220 a subsequent call to integer_zerop will work. Hence we must
5221 do the type conversion here. At this point, the constant is either
5222 zero or one, and the conversion to a signed type can never overflow.
5223 We could get an overflow if this conversion is done anywhere else. */
5232 /* If necessary, convert the type back to match the type of C. */
5237 }
5238 \f
5239 /* Find ways of folding logical expressions of LHS and RHS:
5240 Try to merge two comparisons to the same innermost item.
5241 Look for range tests like "ch >= '0' && ch <= '9'".
5242 Look for combinations of simple terms on machines with expensive branches
5243 and evaluate the RHS unconditionally.
5245 For example, if we have p->a == 2 && p->b == 4 and we can make an
5246 object large enough to span both A and B, we can do this with a comparison
5247 against the object ANDed with the a mask.
5249 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5250 operations to do this with one comparison.
5252 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5253 function and the one above.
5255 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5256 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5258 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5259 two operands.
5261 We return the simplified tree or 0 if no optimization is possible. */
5263 static tree
5265 {
5266 /* If this is the "or" of two comparisons, we can do something if
5267 the comparisons are NE_EXPR. If this is the "and", we can do something
5268 if the comparisons are EQ_EXPR. I.e.,
5269 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5271 WANTED_CODE is this operation code. For single bit fields, we can
5272 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5273 comparison for one-bit fields. */
5295 /* Start by getting the comparison codes. Fail if anything is volatile.
5296 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5297 it were surrounded with a NE_EXPR. */
5306 {
5310 }
5313 {
5317 }
5328 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5331 {
5332 tree result;
5335 {
5340 }
5343 {
5349 }
5350 }
5355 /* If the RHS can be evaluated unconditionally and its operands are
5356 simple, it wins to evaluate the RHS unconditionally on machines
5357 with expensive branches. In this case, this isn't a comparison
5358 that can be merged. Avoid doing this if the RHS is a floating-point
5359 comparison since those can trap. */
5365 {
5366 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5377 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5389 {
5393 }
5394 }
5396 /* See if the comparisons can be merged. Then get all the parameters for
5397 each side. */
5421 /* It must be true that the inner operation on the lhs of each
5422 comparison must be the same if we are to be able to do anything.
5423 Then see if we have constants. If not, the same must be true for
5424 the rhs's. */
5435 else
5438 /* If either comparison code is not correct for our logical operation,
5439 fail. However, we can convert a one-bit comparison against zero into
5440 the opposite comparison against that bit being set in the field. */
5444 {
5446 {
5447 /* Make the left operand unsigned, since we are only interested
5448 in the value of one bit. Otherwise we are doing the wrong
5449 thing below. */
5452 }
5453 else
5455 }
5457 /* This is analogous to the code for l_const above. */
5459 {
5461 {
5464 }
5465 else
5467 }
5469 /* See if we can find a mode that contains both fields being compared on
5470 the left. If we can't, fail. Otherwise, update all constants and masks
5471 to be relative to a field of that size. */
5476 volatilep);
5486 {
5489 }
5497 {
5505 {
5509 }
5510 }
5512 {
5520 {
5524 }
5525 }
5527 /* Handle the case of comparisons with constants. If there is something in
5528 common between the masks, those bits of the constants must be the same.
5529 If not, the condition is always false. Test for this to avoid generating
5530 incorrect code below. */
5535 {
5537 {
5540 }
5541 else
5542 {
5545 }
5546 }
5549 }
5550 \f
5551 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5552 constant. */
5554 static tree
5556 {
5559 tree comp_const;
5560 tree minmax_const;
5562 tree inner;
5573 /* If something does not permit us to optimize, return the original tree. */
5581 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5582 and GT_EXPR, doing the rest with recursive calls using logical
5583 simplifications. */
5585 {
5587 {
5593 }
5596 return
5598 optimize_minmax_comparison
5600 optimize_minmax_comparison
5605 /* MAX (X, 0) == 0 -> X <= 0 */
5609 /* MAX (X, 0) == 5 -> X == 5 */
5613 /* MAX (X, 0) == -1 -> false */
5617 /* MIN (X, 0) == 0 -> X >= 0 */
5621 /* MIN (X, 0) == 5 -> false */
5624 else
5625 /* MIN (X, 0) == -1 -> X == -1 */
5630 /* MAX (X, 0) > 0 -> X > 0
5631 MAX (X, 0) > 5 -> X > 5 */
5635 /* MAX (X, 0) > -1 -> true */
5639 /* MIN (X, 0) > 0 -> false
5640 MIN (X, 0) > 5 -> false */
5643 else
5644 /* MIN (X, 0) > -1 -> X > -1 */
5649 }
5650 }
5651 \f
5652 /* T is an integer expression that is being multiplied, divided, or taken a
5653 modulus (CODE says which and what kind of divide or modulus) by a
5654 constant C. See if we can eliminate that operation by folding it with
5655 other operations already in T. WIDE_TYPE, if non-null, is a type that
5656 should be used for the computation if wider than our type.
5658 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5659 (X * 2) + (Y * 4). We must, however, be assured that either the original
5660 expression would not overflow or that overflow is undefined for the type
5661 in the language in question.
5663 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5664 the machine has a multiply-accumulate insn or that this is part of an
5665 addressing calculation.
5667 If we return a non-null expression, it is an equivalent form of the
5668 original computation, but need not be in the original type.
5670 We set *STRICT_OVERFLOW_P to true if the return values depends on
5671 signed overflow being undefined. Otherwise we do not change
5672 *STRICT_OVERFLOW_P. */
5674 static tree
5677 {
5678 /* To avoid exponential search depth, refuse to allow recursion past
5679 three levels. Beyond that (1) it's highly unlikely that we'll find
5680 something interesting and (2) we've probably processed it before
5681 when we built the inner expression. */
5684 tree ret;
5689 depth++;
5691 depth--;
5694 }
5696 static tree
5699 {
5710 /* Don't deal with constants of zero here; they confuse the code below. */
5720 /* Note that we need not handle conditional operations here since fold
5721 already handles those cases. So just do arithmetic here. */
5723 {
5725 /* For a constant, we can always simplify if we are a multiply
5726 or (for divide and modulus) if it is a multiple of our constant. */
5734 /* If op0 is an expression ... */
5740 /* ... and has wrapping overflow, and its type is smaller
5741 than ctype, then we cannot pass through as widening. */
5747 /* ... or this is a truncation (t is narrower than op0),
5748 then we cannot pass through this narrowing. */
5751 /* ... or signedness changes for division or modulus,
5752 then we cannot pass through this conversion. */
5756 /* ... or has undefined overflow while the converted to
5757 type has not, we cannot do the operation in the inner type
5758 as that would introduce undefined overflow. */
5763 /* Pass the constant down and see if we can make a simplification. If
5764 we can, replace this expression with the inner simplification for
5765 possible later conversion to our or some other type. */
5770 code == MULT_EXPR
5772 strict_overflow_p))))
5777 /* If widening the type changes it from signed to unsigned, then we
5778 must avoid building ABS_EXPR itself as unsigned. */
5780 {
5784 {
5787 }
5789 }
5790 /* If the constant is negative, we cannot simplify this. */
5793 /* FALLTHROUGH */
5801 /* If widening the type changes the signedness, then we can't perform
5802 this optimization as that changes the result. */
5806 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5812 {
5819 }
5823 /* If the second operand is constant, this is a multiplication
5824 or floor division, by a power of two, so we can treat it that
5825 way unless the multiplier or divisor overflows. Signed
5826 left-shift overflow is implementation-defined rather than
5827 undefined in C90, so do not convert signed left shift into
5828 multiplication. */
5831 /* const_binop may not detect overflow correctly,
5832 so check for it explicitly here. */
5837 size_one_node,
5847 /* See if we can eliminate the operation on both sides. If we can, we
5848 can return a new PLUS or MINUS. If we can't, the only remaining
5849 cases where we can do anything are if the second operand is a
5850 constant. */
5856 /* If not multiplication, we can only do this if both operands
5857 are divisible by c. */
5860 {
5865 }
5867 /* If this was a subtraction, negate OP1 and set it to be an addition.
5868 This simplifies the logic below. */
5875 /* If either OP1 or C are negative, this optimization is not safe for
5876 some of the division and remainder types while for others we need
5877 to change the code. */
5879 {
5887 }
5889 /* If it's a multiply or a division/modulus operation of a multiple
5890 of our constant, do the operation and verify it doesn't overflow. */
5893 {
5896 /* We allow the constant to overflow with wrapping semantics. */
5900 }
5901 else
5904 /* If we have an unsigned type is not a sizetype, we cannot widen
5905 the operation since it will change the result if the original
5906 computation overflowed. */
5912 /* If we were able to eliminate our operation from the first side,
5913 apply our operation to the second side and reform the PLUS. */
5917 /* The last case is if we are a multiply. In that case, we can
5918 apply the distributive law to commute the multiply and addition
5919 if the multiplication of the constants doesn't overflow. */
5925 op1);
5930 /* We have a special case here if we are doing something like
5931 (C * 8) % 4 since we know that's zero. */
5938 /* ... fall through ... */
5942 /* If we can extract our operation from the LHS, do so and return a
5943 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5944 do something only if the second operand is a constant. */
5958 /* If these are the same operation types, we can associate them
5959 assuming no overflow. */
5971 /* If these operations "cancel" each other, we have the main
5972 optimizations of this pass, which occur when either constant is a
5973 multiple of the other, in which case we replace this with either an
5974 operation or CODE or TCODE.
5976 If we have an unsigned type that is not a sizetype, we cannot do
5977 this since it will change the result if the original computation
5978 overflowed. */
5986 {
5988 {
5995 }
5997 {
6004 }
6005 }
6010 }
6013 }
6014 \f
6015 /* Return a node which has the indicated constant VALUE (either 0 or
6016 1), and is of the indicated TYPE. */
6018 tree
6020 {
6025 else
6027 }
6030 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6031 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6032 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6033 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6034 COND is the first argument to CODE; otherwise (as in the example
6035 given here), it is the second argument. TYPE is the type of the
6036 original expression. Return NULL_TREE if no simplification is
6037 possible. */
6039 static tree
6043 {
6050 /* This transformation is only worthwhile if we don't have to wrap
6051 arg in a SAVE_EXPR, and the operation can be simplified on at least
6052 one of the branches once its pushed inside the COND_EXPR. */
6057 {
6061 /* If this operand throws an expression, then it does not make
6062 sense to try to perform a logical or arithmetic operation
6063 involving it. */
6068 }
6069 else
6070 {
6075 }
6079 {
6083 else
6085 }
6087 {
6091 else
6093 }
6097 }
6099 \f
6100 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6102 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6103 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6104 ADDEND is the same as X.
6106 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6107 and finite. The problematic cases are when X is zero, and its mode
6108 has signed zeros. In the case of rounding towards -infinity,
6109 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6110 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6112 bool
6114 {
6118 /* Don't allow the fold with -fsignaling-nans. */
6122 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6126 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6131 /* The mode has signed zeros, and we have to honor their sign.
6132 In this situation, there is only one case we can return true for.
6133 X - 0 is the same as X unless rounding towards -infinity is
6134 supported. */
6136 }
6138 /* Subroutine of fold() that checks comparisons of built-in math
6139 functions against real constants.
6141 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6142 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6143 is the type of the result and ARG0 and ARG1 are the operands of the
6144 comparison. ARG1 must be a TREE_REAL_CST.
6146 The function returns the constant folded tree if a simplification
6147 can be made, and NULL_TREE otherwise. */
6149 static tree
6152 {
6153 REAL_VALUE_TYPE c;
6156 {
6162 {
6163 /* sqrt(x) < y is always false, if y is negative. */
6167 /* sqrt(x) > y is always true, if y is negative and we
6168 don't care about NaNs, i.e. negative values of x. */
6172 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6175 }
6177 {
6178 REAL_VALUE_TYPE c2;
6184 {
6185 /* sqrt(x) > y is x == +Inf, when y is very large. */
6190 /* sqrt(x) > y is always false, when y is very large
6191 and we don't care about infinities. */
6193 }
6195 /* sqrt(x) > c is the same as x > c*c. */
6198 }
6200 {
6201 REAL_VALUE_TYPE c2;
6207 {
6208 /* sqrt(x) < y is always true, when y is a very large
6209 value and we don't care about NaNs or Infinities. */
6213 /* sqrt(x) < y is x != +Inf when y is very large and we
6214 don't care about NaNs. */
6219 /* sqrt(x) < y is x >= 0 when y is very large and we
6220 don't care about Infinities. */
6225 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6234 dconst0)),
6237 c2)));
6238 }
6240 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6245 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6248 {
6253 dconst0)),
6256 c2)));
6257 }
6258 }
6259 }
6262 }
6264 /* Subroutine of fold() that optimizes comparisons against Infinities,
6265 either +Inf or -Inf.
6267 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6268 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6269 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6271 The function returns the constant folded tree if a simplification
6272 can be made, and NULL_TREE otherwise. */
6274 static tree
6276 {
6278 REAL_VALUE_TYPE max;
6279 tree temp;
6284 /* For negative infinity swap the sense of the comparison. */
6290 {
6292 /* x > +Inf is always false, if with ignore sNANs. */
6298 /* x <= +Inf is always true, if we don't case about NaNs. */
6302 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6305 {
6308 }
6313 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6319 /* x < +Inf is always equal to x <= DBL_MAX. */
6325 /* x != +Inf is always equal to !(x > DBL_MAX). */
6337 }
6340 }
6342 /* Subroutine of fold() that optimizes comparisons of a division by
6343 a nonzero integer constant against an integer constant, i.e.
6344 X/C1 op C2.
6346 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6347 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6348 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6350 The function returns the constant folded tree if a simplification
6351 can be made, and NULL_TREE otherwise. */
6353 static tree
6355 {
6360 HOST_WIDE_INT hpart;
6365 /* We have to do this the hard way to detect unsigned overflow.
6366 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6377 {
6382 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6390 }
6392 {
6396 {
6415 }
6416 }
6417 else
6418 {
6419 /* A negative divisor reverses the relational operators. */
6425 {
6444 }
6445 }
6448 {
6469 {
6472 }
6477 {
6480 }
6485 {
6488 }
6493 {
6496 }
6501 }
6504 }
6507 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6508 equality/inequality test, then return a simplified form of the test
6509 using a sign testing. Otherwise return NULL. TYPE is the desired
6510 result type. */
6512 static tree
6514 tree result_type)
6515 {
6516 /* If this is testing a single bit, we can optimize the test. */
6520 {
6521 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6522 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6526 /* This is only a win if casting to a signed type is cheap,
6527 i.e. when arg00's type is not a partial mode. */
6530 {
6535 }
6536 }
6539 }
6541 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6542 equality/inequality test, then return a simplified form of
6543 the test using shifts and logical operations. Otherwise return
6544 NULL. TYPE is the desired result type. */
6546 tree
6548 tree result_type)
6549 {
6550 /* If this is testing a single bit, we can optimize the test. */
6554 {
6563 /* First, see if we can fold the single bit test into a sign-bit
6564 test. */
6566 result_type);
6570 /* Otherwise we have (A & C) != 0 where C is a single bit,
6571 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6572 Similarly for (A & C) == 0. */
6574 /* If INNER is a right shift of a constant and it plus BITNUM does
6575 not overflow, adjust BITNUM and INNER. */
6582 {
6585 }
6587 /* If we are going to be able to omit the AND below, we must do our
6588 operations as unsigned. If we must use the AND, we have a choice.
6589 Normally unsigned is faster, but for some machines signed is. */
6590 #ifdef LOAD_EXTEND_OP
6593 #else
6595 #endif
6611 /* Put the AND last so it can combine with more things. */
6614 /* Make sure to return the proper type. */
6618 }
6620 }
6622 /* Check whether we are allowed to reorder operands arg0 and arg1,
6623 such that the evaluation of arg1 occurs before arg0. */
6625 static bool
6627 {
6634 }
6636 /* Test whether it is preferable two swap two operands, ARG0 and
6637 ARG1, for example because ARG0 is an integer constant and ARG1
6638 isn't. If REORDER is true, only recommend swapping if we can
6639 evaluate the operands in reverse order. */
6641 bool
6643 {
6679 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6680 for commutative and comparison operators. Ensuring a canonical
6681 form allows the optimizers to find additional redundancies without
6682 having to explicitly check for both orderings. */
6688 /* Put SSA_NAMEs last. */
6694 /* Put variables last. */
6701 }
6703 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6704 ARG0 is extended to a wider type. */
6706 static tree
6708 {
6710 tree arg1_unw;
6719 #ifdef HAVE_canonicalize_funcptr_for_compare
6720 /* Disable this optimization if we're casting a function pointer
6721 type on targets that require function pointer canonicalization. */
6726 #endif
6733 /* If possible, express the comparison in the shorter mode. */
6755 /* If we are comparing with the integer that does not fit into the range
6756 of the shorter type, the result is known. */
6767 {
6794 }
6797 }
6799 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6800 ARG0 just the signedness is changed. */
6802 static tree
6805 {
6806 tree arg0_inner;
6816 #ifdef HAVE_canonicalize_funcptr_for_compare
6817 /* Disable this optimization if we're casting a function pointer
6818 type on targets that require function pointer canonicalization. */
6823 #endif
6828 /* If the conversion is from an integral subtype to its basetype
6829 leave it alone. */
6848 else
6852 }
6854 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6855 step of the array. Reconstructs s and delta in the case of s * delta
6856 being an integer constant (and thus already folded).
6857 ADDR is the address. MULT is the multiplicative expression.
6858 If the function succeeds, the new address expression is returned. Otherwise
6859 NULL_TREE is returned. */
6861 static tree
6863 {
6867 tree itype;
6870 /* Strip the nops that might be added when converting op1 to sizetype. */
6873 /* Canonicalize op1 into a possibly non-constant delta
6874 and an INTEGER_CST s. */
6876 {
6883 {
6886 }
6888 {
6891 }
6892 else
6894 }
6896 {
6899 }
6900 else
6901 {
6902 /* Simulate we are delta * 1. */
6905 }
6908 {
6910 {
6911 /* Remember if this was a multi-dimensional array. */
6924 {
6927 }
6928 else
6929 {
6930 /* Try if delta is a multiple of step. */
6935 }
6937 /* Only fold here if we can verify we do not overflow one
6938 dimension of a multi-dimensional array. */
6940 {
6941 tree tmp;
6957 }
6960 }
6961 else
6966 }
6968 /* We found the suitable array reference. So copy everything up to it,
6969 and replace the index. */
6976 {
6980 }
6988 }
6991 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6992 means A >= Y && A != MAX, but in this case we know that
6993 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6995 static tree
6997 {
7004 else
7013 {
7016 }
7018 {
7021 }
7022 else
7029 {
7030 /* Convert the pointer types into integer before taking the difference. */
7034 }
7035 else
7042 }
7044 /* Fold a sum or difference of at least one multiplication.
7045 Returns the folded tree or NULL if no simplification could be made. */
7047 static tree
7049 {
7053 /* (A * C) +- (B * C) -> (A+-B) * C.
7054 (A * C) +- A -> A * (C+-1).
7055 We are most concerned about the case where C is a constant,
7056 but other combinations show up during loop reduction. Since
7057 it is not difficult, try all four possibilities. */
7060 {
7063 }
7065 {
7068 }
7069 else
7070 {
7071 /* We cannot generate constant 1 for fract. */
7076 }
7078 {
7081 }
7083 {
7086 }
7087 else
7088 {
7089 /* We cannot generate constant 1 for fract. */
7094 }
7106 /* No identical multiplicands; see if we can find a common
7107 power-of-two factor in non-power-of-two multiplies. This
7108 can help in multi-dimensional array access. */
7111 {
7114 tree maybe_same;
7118 /* Move min of absolute values to int11. */
7121 {
7126 }
7127 else
7131 {
7139 }
7140 }
7150 }
7152 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7153 specified by EXPR into the buffer PTR of length LEN bytes.
7154 Return the number of bytes placed in the buffer, or zero
7155 upon failure. */
7157 static int
7159 {
7170 {
7174 else
7179 {
7186 else
7188 }
7189 else
7192 }
7194 }
7197 /* Subroutine of native_encode_expr. Encode the REAL_CST
7198 specified by EXPR into the buffer PTR of length LEN bytes.
7199 Return the number of bytes placed in the buffer, or zero
7200 upon failure. */
7202 static int
7204 {
7210 /* There are always 32 bits in each long, no matter the size of
7211 the hosts long. We handle floating point representations with
7212 up to 192 bits. */
7223 {
7228 {
7235 else
7237 }
7238 else
7241 }
7243 }
7245 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7246 specified by EXPR into the buffer PTR of length LEN bytes.
7247 Return the number of bytes placed in the buffer, or zero
7248 upon failure. */
7250 static int
7252 {
7254 tree part;
7265 }
7268 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7269 specified by EXPR into the buffer PTR of length LEN bytes.
7270 Return the number of bytes placed in the buffer, or zero
7271 upon failure. */
7273 static int
7275 {
7285 {
7287 {
7290 }
7291 else
7295 {
7298 }
7299 else
7300 {
7304 }
7306 }
7308 }
7311 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7312 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7313 buffer PTR of length LEN bytes. Return the number of bytes
7314 placed in the buffer, or zero upon failure. */
7316 int
7318 {
7320 {
7335 }
7336 }
7339 /* Subroutine of native_interpret_expr. Interpret the contents of
7340 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7341 If the buffer cannot be interpreted, return NULL_TREE. */
7343 static tree
7345 {
7359 {
7362 {
7369 else
7371 }
7372 else
7378 else
7381 }
7384 }
7387 /* Subroutine of native_interpret_expr. Interpret the contents of
7388 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7389 If the buffer cannot be interpreted, return NULL_TREE. */
7391 static tree
7393 {
7398 /* There are always 32 bits in each long, no matter the size of
7399 the hosts long. We handle floating point representations with
7400 up to 192 bits. */
7401 REAL_VALUE_TYPE r;
7412 {
7415 {
7422 else
7424 }
7425 else
7430 }
7434 }
7437 /* Subroutine of native_interpret_expr. Interpret the contents of
7438 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7439 If the buffer cannot be interpreted, return NULL_TREE. */
7441 static tree
7443 {
7458 }
7461 /* Subroutine of native_interpret_expr. Interpret the contents of
7462 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7463 If the buffer cannot be interpreted, return NULL_TREE. */
7465 static tree
7467 {
7479 {
7484 }
7486 }
7489 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7490 the buffer PTR of length LEN as a constant of type TYPE. For
7491 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7492 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7493 return NULL_TREE. */
7495 tree
7497 {
7499 {
7516 }
7517 }
7520 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7521 TYPE at compile-time. If we're unable to perform the conversion
7522 return NULL_TREE. */
7524 static tree
7526 {
7527 /* We support up to 512-bit values (for V8DFmode). */
7531 /* Check that the host and target are sane. */
7540 }
7542 /* Build an expression for the address of T. Folds away INDIRECT_REF
7543 to avoid confusing the gimplify process. When IN_FOLD is true
7544 avoid modifications of T. */
7546 static tree
7548 {
7549 /* The size of the object is not relevant when talking about its address. */
7553 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7556 {
7561 }
7563 {
7573 }
7574 else
7578 }
7580 /* Build an expression for the address of T with type PTRTYPE. This
7581 function modifies the input parameter 'T' by sometimes setting the
7582 TREE_ADDRESSABLE flag. */
7584 tree
7586 {
7588 }
7590 /* Build an expression for the address of T. This function modifies
7591 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7592 flag. When called from fold functions, use fold_addr_expr instead. */
7594 tree
7596 {
7600 }
7602 /* Same as build_fold_addr_expr, builds an expression for the address
7603 of T, but avoids touching the input node 't'. Fold functions
7604 should use this version. */
7606 static tree
7608 {
7612 }
7614 /* Fold a unary expression of code CODE and type TYPE with operand
7615 OP0. Return the folded expression if folding is successful.
7616 Otherwise, return NULL_TREE. */
7618 tree
7620 {
7621 tree tem;
7622 tree arg0;
7630 {
7633 {
7634 /* Don't use STRIP_NOPS, because signedness of argument type
7635 matters. */
7637 }
7638 else
7639 {
7640 /* Strip any conversions that don't change the mode. This
7641 is safe for every expression, except for a comparison
7642 expression because its signedness is derived from its
7643 operands.
7645 Note that this is done as an internal manipulation within
7646 the constant folder, in order to find the simplest
7647 representation of the arguments so that their form can be
7648 studied. In any cases, the appropriate type conversions
7649 should be put back in the tree that will get out of the
7650 constant folder. */
7652 }
7653 }
7656 {
7661 {
7671 /* If this was a conversion, and all we did was to move into
7672 inside the COND_EXPR, bring it back out. But leave it if
7673 it is a conversion from integer to integer and the
7674 result precision is no wider than a word since such a
7675 conversion is cheap and may be optimized away by combine,
7676 while it couldn't if it were outside the COND_EXPR. Then return
7677 so we don't get into an infinite recursion loop taking the
7678 conversion out and then back in. */
7690 && (INTEGRAL_TYPE_P
7702 }
7704 {
7706 {
7710 }
7714 integer_one_node),
7716 integer_zero_node));
7717 }
7718 }
7721 {
7723 /* Re-association barriers around constants and other re-association
7724 barriers can be removed. */
7730 CASE_CONVERT:
7736 /* If we have (type) (a CMP b) and type is an integral type, return
7737 new expression involving the new type. */
7742 /* Handle cases of two conversions in a row. */
7744 {
7766 /* In addition to the cases of two conversions in a row
7767 handled below, if we are converting something to its own
7768 type via an object of identical or wider precision, neither
7769 conversion is needed. */
7776 /* Likewise, if the intermediate and final types are either both
7777 float or both integer, we don't need the middle conversion if
7778 it is wider than the final type and doesn't change the signedness
7779 (for integers). Avoid this if the final type is a pointer
7780 since then we sometimes need the inner conversion. Likewise if
7781 the outer has a precision not equal to the size of its mode. */
7790 && ! final_ptr
7794 /* If we have a sign-extension of a zero-extended value, we can
7795 replace that by a single zero-extension. */
7801 /* Two conversions in a row are not needed unless:
7802 - some conversion is floating-point (overstrict for now), or
7803 - some conversion is a vector (overstrict for now), or
7804 - the intermediate type is narrower than both initial and
7805 final, or
7806 - the intermediate type and innermost type differ in signedness,
7807 and the outermost type is wider than the intermediate, or
7808 - the initial type is a pointer type and the precisions of the
7809 intermediate and final types differ, or
7810 - the final type is a pointer type and the precisions of the
7811 initial and intermediate types differ. */
7825 }
7827 /* Handle (T *)&A.B.C for A being of type T and B and C
7828 living at offset zero. This occurs frequently in
7829 C++ upcasting and then accessing the base. */
7833 {
7835 tree offset;
7841 /* If the reference was to a (constant) zero offset, we can use
7842 the address of the base if it has the same base type
7843 as the result type. */
7848 }
7853 /* Detect assigning a bitfield. */
7855 && DECL_BIT_FIELD
7857 {
7858 /* Don't leave an assignment inside a conversion
7859 unless assigning a bitfield. */
7861 /* First do the assignment, then return converted constant. */
7866 }
7868 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7869 constants (if x has signed type, the sign bit cannot be set
7870 in c). This folds extension into the BIT_AND_EXPR.
7871 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7872 very likely don't have maximal range for their precision and this
7873 transformation effectively doesn't preserve non-maximal ranges. */
7877 {
7887 <= HOST_BITS_PER_WIDE_INT
7889 {
7896 #ifdef LOAD_EXTEND_OP
7898 && !flag_syntax_only
7901 {
7905 }
7906 #endif
7907 }
7909 {
7915 }
7916 }
7918 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7919 when one of the new casts will fold away. Conservatively we assume
7920 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7926 {
7932 }
7934 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7935 of the same precision, and X is an integer type not narrower than
7936 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7942 {
7947 }
7949 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7950 type of X and Y (integer types only). */
7955 {
7956 /* Be careful not to introduce new overflows. */
7957 tree mult_type;
7960 else
7967 }
7982 /* For integral conversions with the same precision or pointer
7983 conversions use a NOP_EXPR instead. */
7989 /* Do not muck with VIEW_CONVERT_EXPRs that convert from
7990 a sub-type to its base type as generated by the Ada FE. */
7995 /* Strip inner integral conversions that do not change the precision. */
8018 /* Convert fabs((double)float) into (double)fabsf(float). */
8021 {
8026 targ0));
8027 }
8028 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8034 /* Strip sign ops from argument. */
8036 {
8040 }
8047 {
8052 }
8054 {
8059 }
8069 /* Convert ~ (-A) to A - 1. */
8074 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8082 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8095 /* Perform BIT_NOT_EXPR on each element individually. */
8097 {
8102 {
8104 {
8110 }
8111 else
8114 }
8117 }
8122 /* The argument to invert_truthvalue must have Boolean type. */
8126 /* Note that the operand of this must be an int
8127 and its values must be 0 or 1.
8128 ("true" is a fixed value perhaps depending on the language,
8129 but we don't handle values other than 1 correctly yet.) */
8144 {
8152 }
8154 {
8158 }
8160 {
8164 {
8173 }
8174 }
8186 {
8194 }
8196 {
8200 }
8202 {
8206 {
8215 }
8216 }
8222 }
8224 /* Fold a binary expression of code CODE and type TYPE with operands
8225 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8226 Return the folded expression if folding is successful. Otherwise,
8227 return NULL_TREE. */
8229 static tree
8231 {
8238 else
8241 /* MIN (MAX (a, b), b) == b. */
8246 /* MIN (MAX (b, a), b) == b. */
8252 /* MIN (a, MAX (a, b)) == a. */
8258 /* MIN (a, MAX (b, a)) == a. */
8265 }
8267 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8268 by changing CODE to reduce the magnitude of constants involved in
8269 ARG0 of the comparison.
8270 Returns a canonicalized comparison tree if a simplification was
8271 possible, otherwise returns NULL_TREE.
8272 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8273 valid if signed overflow is undefined. */
8275 static tree
8279 {
8285 /* Match A +- CST code arg1 and CST code arg1. */
8292 /* Identify the constant in arg0 and its sign. */
8295 else
8299 /* Overflowed constants and zero will cause problems. */
8304 /* See if we can reduce the magnitude of the constant in
8305 arg0 by changing the comparison code. */
8307 {
8308 /* CST <= arg1 -> CST-1 < arg1. */
8311 /* -CST < arg1 -> -CST-1 <= arg1. */
8314 /* CST > arg1 -> CST-1 >= arg1. */
8317 /* -CST >= arg1 -> -CST-1 > arg1. */
8320 else
8322 /* arg1 code' CST' might be more canonical. */
8324 }
8325 else
8326 {
8327 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8331 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8335 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8339 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8343 else
8346 }
8348 /* Now build the constant reduced in magnitude. */
8354 /* If swapping might yield to a more canonical form, do so. */
8357 else
8359 }
8361 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8362 overflow further. Try to decrease the magnitude of constants involved
8363 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8364 and put sole constants at the second argument position.
8365 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8367 static tree
8370 {
8371 tree t;
8376 /* In principle pointers also have undefined overflow behavior,
8377 but that causes problems elsewhere. */
8382 /* Try canonicalization by simplifying arg0. */
8387 {
8391 }
8393 /* Try canonicalization by simplifying arg1 using the swapped
8394 comparison. */
8402 }
8404 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8405 space. This is used to avoid issuing overflow warnings for
8406 expressions like &p->x which can not wrap. */
8408 static bool
8410 {
8421 {
8424 }
8427 else
8428 {
8431 }
8446 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8447 array. */
8449 {
8450 HOST_WIDE_INT base_size;
8455 }
8458 }
8460 /* Subroutine of fold_binary. This routine performs all of the
8461 transformations that are common to the equality/inequality
8462 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8463 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8464 fold_binary should call fold_binary. Fold a comparison with
8465 tree code CODE and type TYPE with operands OP0 and OP1. Return
8466 the folded comparison or NULL_TREE. */
8468 static tree
8470 {
8483 /* If one arg is a real or integer constant, put it last. */
8487 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8494 {
8498 tree lhs;
8505 /* If the constant operation overflowed this can be
8506 simplified as a comparison against INT_MAX/INT_MIN. */
8509 {
8513 /* Get the sign of the constant on the lhs if the
8514 operation were VARIABLE + CONST1. */
8518 /* The sign of the constant determines if we overflowed
8519 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8520 Canonicalize to the INT_MIN overflow by swapping the comparison
8521 if necessary. */
8525 /* We now can look at the canonicalized case
8526 VARIABLE + 1 CODE2 INT_MIN
8527 and decide on the result. */
8536 }
8541 {
8543 "when changing X +- C1 cmp C2 to "
8545 WARN_STRICT_OVERFLOW_COMPARISON);
8547 }
8548 }
8550 /* For comparisons of pointers we can decompose it to a compile time
8551 comparison of the base objects and the offsets into the object.
8552 This requires at least one operand being an ADDR_EXPR or a
8553 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8559 {
8566 /* Get base and offset for the access. Strip ADDR_EXPR for
8567 get_inner_reference, but put it back by stripping INDIRECT_REF
8568 off the base object if possible. indirect_baseN will be true
8569 if baseN is not an address but refers to the object itself. */
8572 {
8578 else
8580 }
8582 {
8585 }
8589 {
8595 else
8597 }
8599 {
8602 }
8604 /* If we have equivalent bases we might be able to simplify. */
8607 {
8608 /* We can fold this expression to a constant if the non-constant
8609 offset parts are equal. */
8617 {
8624 "occur when comparing P +- C1 with "
8626 WARN_STRICT_OVERFLOW_CONDITIONAL);
8629 {
8643 }
8644 }
8645 /* We can simplify the comparison to a comparison of the variable
8646 offset parts if the constant offset parts are equal.
8647 Be careful to use signed size type here because otherwise we
8648 mess with array offsets in the wrong way. This is possible
8649 because pointer arithmetic is restricted to retain within an
8650 object and overflow on pointer differences is undefined as of
8651 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8655 {
8656 tree signed_size_type_node;
8659 /* By converting to signed size type we cover middle-end pointer
8660 arithmetic which operates on unsigned pointer types of size
8661 type size and ARRAY_REF offsets which are properly sign or
8662 zero extended from their type in case it is narrower than
8663 size type. */
8666 else
8670 else
8678 "occur when comparing P +- C1 with "
8680 WARN_STRICT_OVERFLOW_COMPARISON);
8683 }
8684 }
8685 /* For non-equal bases we can simplify if they are addresses
8686 of local binding decls or constants. */
8688 /* We know that !operand_equal_p (base0, base1, 0)
8689 because the if condition was false. But make
8690 sure two decls are not the same. */
8704 {
8709 }
8710 /* For equal offsets we can simplify to a comparison of the
8711 base addresses. */
8713 && (indirect_base0
8715 && (indirect_base1
8720 {
8726 }
8727 }
8729 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8730 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8731 the resulting offset is smaller in absolute value than the
8732 original one. */
8740 {
8745 tree cst;
8747 "occur when combining constants around "
8750 /* Put the constant on the side where it doesn't overflow and is
8751 of lower absolute value than before. */
8757 {
8760 variable1,
8763 }
8770 {
8775 variable2);
8776 }
8777 }
8779 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8780 signed arithmetic case. That form is created by the compiler
8781 often enough for folding it to be of value. One example is in
8782 computing loop trip counts after Operator Strength Reduction. */
8788 {
8797 "eliminating multiplication in comparison "
8799 WARN_STRICT_OVERFLOW_COMPARISON);
8801 /* If const1 is negative we swap the sense of the comparison. */
8806 }
8813 {
8821 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8826 /* (-a) CMP (-b) -> b CMP a */
8833 {
8834 REAL_VALUE_TYPE cst;
8837 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8844 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8845 /* a CMP (-0) -> a CMP 0 */
8850 /* x != NaN is always true, other ops are always false. */
8853 {
8856 }
8858 /* Fold comparisons against infinity. */
8860 {
8864 }
8865 }
8867 /* If this is a comparison of a real constant with a PLUS_EXPR
8868 or a MINUS_EXPR of a real constant, we can convert it into a
8869 comparison with a revised real constant as long as no overflow
8870 occurs when unsafe_math_optimizations are enabled. */
8882 /* Likewise, we can simplify a comparison of a real constant with
8883 a MINUS_EXPR whose first operand is also a real constant, i.e.
8884 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
8885 floating-point types only if -fassociative-math is set. */
8896 /* Fold comparisons against built-in math functions. */
8898 && flag_unsafe_math_optimizations
8900 {
8904 {
8908 }
8909 }
8910 }
8914 {
8915 /* If we are widening one operand of an integer comparison,
8916 see if the other operand is similarly being widened. Perhaps we
8917 can do the comparison in the narrower type. */
8922 /* Or if we are changing signedness. */
8926 }
8928 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8929 constant, we can simplify it. */
8934 {
8938 }
8940 /* Simplify comparison of something with itself. (For IEEE
8941 floating-point, we can only do some of these simplifications.) */
8943 {
8945 {
8960 /* For NE, we can only do this simplification if integer
8961 or we don't honor IEEE floating point NaNs. */
8965 /* ... fall through ... */
8971 }
8972 }
8974 /* If we are comparing an expression that just has comparisons
8975 of two integer values, arithmetic expressions of those comparisons,
8976 and constants, we can simplify it. There are only three cases
8977 to check: the two values can either be equal, the first can be
8978 greater, or the second can be greater. Fold the expression for
8979 those three values. Since each value must be 0 or 1, we have
8980 eight possibilities, each of which corresponds to the constant 0
8981 or 1 or one of the six possible comparisons.
8983 This handles common cases like (a > b) == 0 but also handles
8984 expressions like ((x > y) - (y > x)) > 0, which supposedly
8985 occur in macroized code. */
8988 {
8993 /* Don't handle degenerate cases here; they should already
8994 have been handled anyway. */
9003 {
9007 /* We can't just pass T to eval_subst in case cval1 or cval2
9008 was the same as ARG1. */
9010 tree high_result
9014 arg1);
9015 tree equal_result
9019 arg1);
9020 tree low_result
9024 arg1);
9026 /* All three of these results should be 0 or 1. Confirm they are.
9027 Then use those values to select the proper code to use. */
9032 {
9033 /* Make a 3-bit mask with the high-order bit being the
9034 value for `>', the next for '=', and the low for '<'. */
9038 {
9040 /* Always false. */
9061 /* Always true. */
9063 }
9068 }
9069 }
9070 }
9072 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9073 into a single range test. */
9081 {
9085 }
9087 /* Fold ~X op ~Y as Y op X. */
9090 {
9095 }
9097 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9100 {
9106 }
9109 }
9112 /* Subroutine of fold_binary. Optimize complex multiplications of the
9113 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9114 argument EXPR represents the expression "z" of type TYPE. */
9116 static tree
9118 {
9123 {
9126 }
9128 {
9131 }
9132 else
9133 {
9137 }
9146 }
9149 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9150 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9151 guarantees that P and N have the same least significant log2(M) bits.
9152 N is not otherwise constrained. In particular, N is not normalized to
9153 0 <= N < M as is common. In general, the precise value of P is unknown.
9154 M is chosen as large as possible such that constant N can be determined.
9156 Returns M and sets *RESIDUE to N. */
9158 static unsigned HOST_WIDE_INT
9160 {
9167 {
9170 {
9172 tree offset;
9180 {
9183 else
9184 /* We don't handle more complicated offset expressions. */
9186 }
9187 }
9191 }
9193 {
9206 {
9209 }
9211 {
9214 {
9217 /* Compute the greatest power-of-2 divisor of op1. */
9221 /* If align is non-zero and less than *modulus, replace
9222 *modulus with align., If align is 0, then either op1 is 0
9223 or the greatest power-of-2 divisor of op1 doesn't fit in an
9224 unsigned HOST_WIDE_INT. In either case, no additional
9225 constraint is imposed. */
9230 }
9231 }
9232 }
9234 /* If we get here, we were unable to determine anything useful about the
9235 expression. */
9237 }
9240 /* Fold a binary expression of code CODE and type TYPE with operands
9241 OP0 and OP1. Return the folded expression if folding is
9242 successful. Otherwise, return NULL_TREE. */
9244 tree
9246 {
9261 /* Strip any conversions that don't change the mode. This is
9262 safe for every expression, except for a comparison expression
9263 because its signedness is derived from its operands. So, in
9264 the latter case, only strip conversions that don't change the
9265 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9266 preserved.
9268 Note that this is done as an internal manipulation within the
9269 constant folder, in order to find the simplest representation
9270 of the arguments so that their form can be studied. In any
9271 cases, the appropriate type conversions should be put back in
9272 the tree that will get out of the constant folder. */
9275 {
9278 }
9279 else
9280 {
9283 }
9285 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9286 constant but we can't do arithmetic on them. */
9293 {
9295 {
9296 /* Make sure type and arg0 have the same saturating flag. */
9300 }
9303 else
9307 {
9311 }
9312 }
9314 /* If this is a commutative operation, and ARG0 is a constant, move it
9315 to ARG1 to reduce the number of tests below. */
9320 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9322 First check for cases where an arithmetic operation is applied to a
9323 compound, conditional, or comparison operation. Push the arithmetic
9324 operation inside the compound or conditional to see if any folding
9325 can then be done. Convert comparison to conditional for this purpose.
9326 The also optimizes non-constant cases that used to be done in
9327 expand_expr.
9329 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9330 one of the operands is a comparison and the other is a comparison, a
9331 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9332 code below would make the expression more complex. Change it to a
9333 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9334 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9346 {
9350 boolean_type_node,
9358 }
9362 {
9368 op1));
9377 {
9383 }
9386 {
9392 }
9393 }
9396 {
9398 /* 0 +p index -> (type)index */
9402 /* PTR +p 0 -> PTR */
9406 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9413 /* index +p PTR -> PTR +p index */
9420 /* (PTR +p B) +p A -> PTR +p (B + A) */
9422 {
9423 tree inner;
9431 }
9433 /* PTR_CST +p CST -> CST1 */
9437 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9438 of the array. Loop optimizer sometimes produce this type of
9439 expressions. */
9441 {
9445 }
9450 /* PTR + INT -> (INT)(PTR p+ INT) */
9455 arg0,
9457 /* INT + PTR -> (INT)(PTR p+ INT) */
9462 arg1,
9464 /* A + (-B) -> A - B */
9469 /* (-A) + B -> B - A */
9477 {
9478 /* Convert ~A + 1 to -A. */
9483 /* ~X + X is -1. */
9486 {
9491 {
9494 }
9495 }
9497 /* X + ~X is -1. */
9500 {
9505 {
9508 }
9509 }
9511 /* X + (X / CST) * -CST is X % CST. */
9516 {
9524 }
9525 }
9527 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9528 same or one. Make sure type is not saturating.
9529 fold_plusminus_mult_expr will re-associate. */
9534 {
9538 }
9541 {
9545 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9546 with a constant, and the two constants have no bits in common,
9547 we should treat this as a BIT_IOR_EXPR since this may produce more
9548 simplifications. */
9556 {
9559 }
9561 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9562 (plus (plus (mult) (mult)) (foo)) so that we can
9563 take advantage of the factoring cases below. */
9570 {
9576 else
9598 parg1)));
9599 }
9600 }
9601 else
9602 {
9603 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9607 /* Likewise if the operands are reversed. */
9611 /* Convert X + -C into X - C. */
9614 {
9620 }
9622 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9623 to __complex__ ( x, y ). This is not the same for SNaNs or
9624 if signed zeros are involved. */
9628 {
9635 {
9639 {
9645 }
9647 {
9653 }
9654 }
9655 }
9663 /* Convert x+x into x*2.0. */
9669 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9670 We associate floats only if the user has specified
9671 -fassociative-math. */
9675 {
9680 {
9681 tree tree0;
9684 }
9685 }
9686 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9687 We associate floats only if the user has specified
9688 -fassociative-math. */
9692 {
9697 {
9698 tree tree0;
9701 }
9702 }
9703 }
9705 bit_rotate:
9706 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9707 is a rotate of A by C1 bits. */
9708 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9709 is a rotate of A by B bits. */
9710 {
9712 tree rtype;
9721 /* Only create rotates in complete modes. Other cases are not
9722 expanded properly. */
9724 {
9743 {
9751 TYPE_PRECISION
9756 ? LROTATE_EXPR
9759 }
9761 {
9769 TYPE_PRECISION
9774 ? LROTATE_EXPR
9777 }
9778 }
9779 }
9781 associate:
9782 /* In most languages, can't associate operations on floats through
9783 parentheses. Rather than remember where the parentheses were, we
9784 don't associate floats at all, unless the user has specified
9785 -fassociative-math.
9786 And, we need to make sure type is not saturating. */
9790 {
9795 /* Split both trees into variables, constants, and literals. Then
9796 associate each group together, the constants with literals,
9797 then the result with variables. This increases the chances of
9798 literals being recombined later and of generating relocatable
9799 expressions for the sum of a constant and literal. */
9804 /* With undefined overflow we can only associate constants
9805 with one variable. */
9809 {
9817 /* The only case we can still associate with two variables
9818 is if they are the same, modulo negation. */
9821 }
9823 /* Only do something if we found more than two objects. Otherwise,
9824 nothing has changed and we risk infinite recursion. */
9830 {
9831 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9840 /* Preserve the MINUS_EXPR if the negative part of the literal is
9841 greater than the positive part. Otherwise, the multiplicative
9842 folding code (i.e extract_muldiv) may be fooled in case
9843 unsigned constants are subtracted, like in the following
9844 example: ((X*2 + 4) - 8U)/2. */
9846 {
9850 {
9854 }
9855 else
9856 {
9860 }
9861 }
9863 {
9868 else
9869 {
9875 }
9876 }
9881 }
9882 }
9887 /* Pointer simplifications for subtraction, simple reassociations. */
9889 {
9890 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
9893 {
9901 }
9902 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
9904 {
9910 }
9911 }
9912 /* A - (-B) -> A + B */
9916 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9925 /* Convert -A - 1 to ~A. */
9933 /* Convert -1 - A to ~A. */
9939 /* X - (X / CST) * CST is X % CST. */
9952 {
9958 /* Fold A - (A & B) into ~B & A. */
9961 {
9963 {
9968 }
9970 {
9975 }
9976 }
9978 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
9979 any power of 2 minus 1. */
9984 {
9990 {
9994 }
9995 }
9996 }
9998 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10002 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10003 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10004 (-ARG1 + ARG0) reduces to -ARG1. */
10008 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10009 __complex__ ( x, -y ). This is not the same for SNaNs or if
10010 signed zeros are involved. */
10014 {
10021 {
10025 {
10027 arg1r ? arg1r
10032 }
10034 {
10038 arg1i ? arg1i
10041 }
10042 }
10043 }
10045 /* Fold &x - &x. This can happen from &x.foo - &x.
10046 This is unsafe for certain floats even in non-IEEE formats.
10047 In IEEE, it is unsafe because it does wrong for NaNs.
10048 Also note that operand_equal_p is always false if an operand
10049 is volatile. */
10055 /* A - B -> A + (-B) if B is easily negatable. */
10058 /* Avoid this transformation if B is a positive REAL_CST. */
10066 /* Try folding difference of addresses. */
10067 {
10068 HOST_WIDE_INT diff;
10074 }
10076 /* Fold &a[i] - &a[j] to i-j. */
10081 {
10086 {
10094 }
10095 }
10103 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10104 same or one. Make sure type is not saturating.
10105 fold_plusminus_mult_expr will re-associate. */
10110 {
10114 }
10119 /* (-A) * (-B) -> A * B */
10130 {
10135 /* Transform x * -1 into -x. Make sure to do the negation
10136 on the original operand with conversions not stripped
10137 because we can only strip non-sign-changing conversions. */
10140 /* Transform x * -C into -x * C if x is easily negatable. */
10149 /* (a * (1 << b)) is (a << b) */
10159 /* (A + A) * C -> A * 2 * C */
10174 {
10177 "occur when simplifying "
10179 WARN_STRICT_OVERFLOW_MISC);
10181 }
10183 /* Optimize z * conj(z) for integer complex numbers. */
10190 }
10191 else
10192 {
10193 /* Maybe fold x * 0 to 0. The expressions aren't the same
10194 when x is NaN, since x * 0 is also NaN. Nor are they the
10195 same in modes with signed zeros, since multiplying a
10196 negative value by 0 gives -0, not +0. */
10201 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10206 /* Transform x * -1.0 into -x. */
10211 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10212 the result for floating point types due to rounding so it is applied
10213 only if -fassociative-math was specify. */
10218 {
10224 }
10226 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10228 {
10231 {
10234 }
10235 }
10237 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10238 This is not the same for NaNs or if signed zeros are
10239 involved. */
10245 {
10257 }
10259 /* Optimize z * conj(z) for floating point complex numbers.
10260 Guarded by flag_unsafe_math_optimizations as non-finite
10261 imaginary components don't produce scalar results. */
10272 {
10276 /* Optimizations of root(...)*root(...). */
10278 {
10283 /* Optimize sqrt(x)*sqrt(x) as x. */
10289 /* Optimize root(x)*root(y) as root(x*y). */
10293 }
10295 /* Optimize expN(x)*expN(y) as expN(x+y). */
10297 {
10303 }
10305 /* Optimizations of pow(...)*pow(...). */
10309 {
10315 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10317 {
10321 }
10323 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10325 {
10329 }
10330 }
10332 /* Optimize tan(x)*cos(x) as sin(x). */
10341 {
10346 }
10348 /* Optimize x*pow(x,c) as pow(x,c+1). */
10352 {
10358 {
10360 REAL_VALUE_TYPE c;
10361 tree arg;
10367 }
10368 }
10370 /* Optimize pow(x,c)*x as pow(x,c+1). */
10374 {
10380 {
10382 REAL_VALUE_TYPE c;
10383 tree arg;
10389 }
10390 }
10392 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10395 {
10399 {
10402 }
10403 }
10404 }
10405 }
10409 bit_ior:
10417 /* ~X | X is -1. */
10420 {
10424 }
10426 /* X | ~X is -1. */
10429 {
10433 }
10435 /* Canonicalize (X & C1) | C2. */
10439 {
10447 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10452 {
10456 }
10457 else
10458 {
10462 }
10464 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10469 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10470 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10471 mode which allows further optimizations. */
10481 {
10482 unsigned HOST_WIDE_INT mask
10486 {
10490 }
10491 }
10498 arg1);
10499 }
10501 /* (X & Y) | Y is (X, Y). */
10505 /* (X & Y) | X is (Y, X). */
10510 /* X | (X & Y) is (Y, X). */
10515 /* X | (Y & X) is (Y, X). */
10525 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10527 This results in more efficient code for machines without a NAND
10528 instruction. Combine will canonicalize to the first form
10529 which will allow use of NAND instructions provided by the
10530 backend if they exist. */
10533 {
10540 }
10542 /* See if this can be simplified into a rotate first. If that
10543 is unsuccessful continue in the association code. */
10554 /* ~X ^ X is -1. */
10557 {
10561 }
10563 /* X ^ ~X is -1. */
10566 {
10570 }
10572 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10573 with a constant, and the two constants have no bits in common,
10574 we should treat this as a BIT_IOR_EXPR since this may produce more
10575 simplifications. */
10583 {
10586 }
10588 /* (X | Y) ^ X -> Y & ~ X*/
10591 {
10594 arg1);
10598 }
10600 /* (Y | X) ^ X -> Y & ~ X*/
10603 {
10606 arg1);
10610 }
10612 /* X ^ (X | Y) -> Y & ~ X*/
10615 {
10618 arg0);
10622 }
10624 /* X ^ (Y | X) -> Y & ~ X*/
10627 {
10630 arg0);
10634 }
10636 /* Convert ~X ^ ~Y to X ^ Y. */
10643 /* Convert ~X ^ C to X ^ ~C. */
10650 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10657 /* Fold (X & Y) ^ Y as ~X & Y. */
10660 {
10665 }
10666 /* Fold (X & Y) ^ X as ~Y & X. */
10670 {
10675 }
10676 /* Fold X ^ (X & Y) as X & ~Y. */
10679 {
10684 }
10685 /* Fold X ^ (Y & X) as ~Y & X. */
10689 {
10694 }
10696 /* See if this can be simplified into a rotate first. If that
10697 is unsuccessful continue in the association code. */
10708 /* ~X & X is always zero. */
10713 /* X & ~X is always zero. */
10718 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10722 {
10731 }
10733 /* (X | Y) & Y is (X, Y). */
10737 /* (X | Y) & X is (Y, X). */
10742 /* X & (X | Y) is (Y, X). */
10747 /* X & (Y | X) is (Y, X). */
10753 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10757 {
10763 }
10764 /* Fold ~X & 1 as (X & 1) == 0. */
10767 {
10773 }
10775 /* Fold (X ^ Y) & Y as ~X & Y. */
10778 {
10783 }
10784 /* Fold (X ^ Y) & X as ~Y & X. */
10788 {
10793 }
10794 /* Fold X & (X ^ Y) as X & ~Y. */
10797 {
10802 }
10803 /* Fold X & (Y ^ X) as ~Y & X. */
10807 {
10812 }
10817 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10820 {
10821 unsigned int prec
10828 }
10830 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10832 This results in more efficient code for machines without a NOR
10833 instruction. Combine will canonicalize to the first form
10834 which will allow use of NOR instructions provided by the
10835 backend if they exist. */
10838 {
10845 }
10847 /* If arg0 is derived from the address of an object or function, we may
10848 be able to fold this expression using the object or function's
10849 alignment. */
10851 {
10857 /* This works because modulus is a power of 2. If this weren't the
10858 case, we'd have to replace it by its greatest power-of-2
10859 divisor: modulus & -modulus. */
10862 }
10864 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
10865 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
10866 if the new mask might be further optimized. */
10875 {
10877 unsigned HOST_WIDE_INT mask
10887 {
10890 /* See if more bits can be proven as zero because of
10891 zero extension. */
10894 {
10899 {
10901 /* See if we can shorten the right shift. */
10904 }
10905 }
10909 /* For arithmetic shift if sign bit could be set, zerobits
10910 can contain actually sign bits, so no transformation is
10911 possible, unless MASK masks them all away. In that
10912 case the shift needs to be converted into logical shift. */
10915 {
10918 else
10920 }
10921 }
10923 /* ((X << 16) & 0xff00) is (X, 0). */
10929 {
10932 /* Only do the transformation if NEWMASK is some integer
10933 mode's mask. */
10940 {
10942 {
10948 }
10949 else
10953 newmask));
10954 }
10955 }
10956 }
10961 /* Don't touch a floating-point divide by zero unless the mode
10962 of the constant can represent infinity. */
10968 /* Optimize A / A to 1.0 if we don't care about
10969 NaNs or Infinities. Skip the transformation
10970 for non-real operands. */
10975 {
10979 }
10981 /* The complex version of the above A / A optimization. */
10984 {
10988 {
10990 /* omit_two_operands will call fold_convert for us. */
10992 }
10993 }
10995 /* (-A) / (-B) -> A / B */
11005 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11010 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11015 /* If ARG1 is a constant, we can convert this to a multiply by the
11016 reciprocal. This does not have the same rounding properties,
11017 so only do this if -freciprocal-math. We can actually
11018 always safely do it if ARG1 is a power of two, but it's hard to
11019 tell if it is or not in a portable manner. */
11021 {
11026 /* Find the reciprocal if optimizing and the result is exact. */
11028 {
11029 REAL_VALUE_TYPE r;
11032 {
11036 }
11037 }
11038 }
11039 /* Convert A/B/C to A/(B*C). */
11046 /* Convert A/(B/C) to (A/B)*C. */
11054 /* Convert C1/(X*C2) into (C1/C2)/X. */
11059 {
11065 }
11068 {
11072 /* Optimize sin(x)/cos(x) as tan(x). */
11078 {
11083 }
11085 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11091 {
11095 {
11099 }
11100 }
11102 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11103 NaNs or Infinities. */
11107 {
11114 {
11119 }
11120 }
11122 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11123 NaNs or Infinities. */
11127 {
11134 {
11138 {
11142 tmp);
11143 }
11144 }
11145 }
11147 /* Optimize pow(x,c)/x as pow(x,c-1). */
11151 {
11157 {
11159 REAL_VALUE_TYPE c;
11160 tree arg;
11166 }
11167 }
11169 /* Optimize a/root(b/c) into a*root(c/b). */
11171 {
11175 {
11184 }
11185 }
11187 /* Optimize x/expN(y) into x*expN(-y). */
11189 {
11194 }
11196 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11200 {
11207 }
11208 }
11213 /* Simplify A / (B << N) where A and B are positive and B is
11214 a power of 2, to A >> (N + log2(B)). */
11219 {
11222 {
11229 WARN_STRICT_OVERFLOW_MISC);
11235 }
11236 }
11238 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11239 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11245 /* Fall thru */
11254 /* X / -1 is -X. */
11261 /* Convert -A / -B to A / B when the type is signed and overflow is
11262 undefined. */
11266 {
11269 "when distributing negation across "
11271 WARN_STRICT_OVERFLOW_MISC);
11275 }
11279 {
11282 "when distributing negation across "
11284 WARN_STRICT_OVERFLOW_MISC);
11287 }
11289 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11290 operation, EXACT_DIV_EXPR.
11292 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11293 At one time others generated faster code, it's not clear if they do
11294 after the last round to changes to the DIV code in expmed.c. */
11303 {
11307 WARN_STRICT_OVERFLOW_MISC);
11309 }
11317 /* X % 1 is always zero, but be sure to preserve any side
11318 effects in X. */
11322 /* X % 0, return X % 0 unchanged so that we can get the
11323 proper warnings and errors. */
11327 /* 0 % X is always zero, but be sure to preserve any side
11328 effects in X. Place this after checking for X == 0. */
11332 /* X % -1 is zero. */
11339 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11340 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11345 {
11347 /* Also optimize A % (C << N) where C is a power of 2,
11348 to A & ((C << N) - 1). */
11353 {
11358 "occur when simplifying "
11360 WARN_STRICT_OVERFLOW_MISC);
11364 }
11365 }
11367 /* X % -C is the same as X % C. */
11374 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11379 /* X % -Y is the same as X % Y. */
11390 {
11394 WARN_STRICT_OVERFLOW_MISC);
11396 }
11407 /* Optimize -1 >> x for arithmetic right shifts. */
11410 /* ... fall through ... */
11413 shift:
11419 /* Since negative shift count is not well-defined,
11420 don't try to compute it in the compiler. */
11424 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11429 {
11433 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11434 being well defined. */
11436 {
11441 else
11443 }
11447 }
11449 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11450 into x & ((unsigned)-1 >> c) for unsigned types. */
11458 {
11461 tree lshift;
11462 tree arg00;
11465 {
11472 }
11473 }
11475 /* Rewrite an LROTATE_EXPR by a constant into an
11476 RROTATE_EXPR by a new constant. */
11478 {
11483 }
11485 /* If we have a rotate of a bit operation with the rotate count and
11486 the second operand of the bit operation both constant,
11487 permute the two operations. */
11499 /* Two consecutive rotates adding up to the precision of the
11500 type can be ignored. */
11511 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11512 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11513 if the latter can be further optimized. */
11518 {
11521 arg1);
11524 arg1);
11528 }
11556 /* Note that the operands of this must be ints
11557 and their values must be 0 or 1.
11558 ("true" is a fixed value perhaps depending on the language.) */
11559 /* If first arg is constant zero, return it. */
11563 /* If either arg is constant true, drop it. */
11567 /* Preserve sequence points. */
11570 /* If second arg is constant zero, result is zero, but first arg
11571 must be evaluated. */
11574 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11575 case will be handled here. */
11579 /* !X && X is always false. */
11583 /* X && !X is always false. */
11588 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11589 means A >= Y && A != MAX, but in this case we know that
11590 A < X <= MAX. */
11594 {
11602 }
11604 truth_andor:
11605 /* We only do these simplifications if we are optimizing. */
11609 /* Check for things like (A || B) && (A || C). We can convert this
11610 to A || (B && C). Note that either operator can be any of the four
11611 truth and/or operations and the transformation will still be
11612 valid. Also note that we only care about order for the
11613 ANDIF and ORIF operators. If B contains side effects, this
11614 might change the truth-value of A. */
11621 {
11641 /* This case if tricky because we must either have commutative
11642 operators or else A10 must not have side-effects. */
11648 a01);
11649 }
11651 /* See if we can build a range comparison. */
11655 /* Check for the possibility of merging component references. If our
11656 lhs is another similar operation, try to merge its rhs with our
11657 rhs. Then try to merge our lhs and rhs. */
11669 /* Note that the operands of this must be ints
11670 and their values must be 0 or true.
11671 ("true" is a fixed value perhaps depending on the language.) */
11672 /* If first arg is constant true, return it. */
11676 /* If either arg is constant zero, drop it. */
11680 /* Preserve sequence points. */
11683 /* If second arg is constant true, result is true, but we must
11684 evaluate first arg. */
11687 /* Likewise for first arg, but note this only occurs here for
11688 TRUTH_OR_EXPR. */
11692 /* !X || X is always true. */
11696 /* X || !X is always true. */
11704 /* If the second arg is constant zero, drop it. */
11707 /* If the second arg is constant true, this is a logical inversion. */
11709 {
11710 /* Only call invert_truthvalue if operand is a truth value. */
11713 else
11716 }
11717 /* Identical arguments cancel to zero. */
11721 /* !X ^ X is always true. */
11726 /* X ^ !X is always true. */
11739 /* bool_var != 0 becomes bool_var. */
11744 /* bool_var == 1 becomes bool_var. */
11749 /* bool_var != 1 becomes !bool_var. */
11754 /* bool_var == 0 becomes !bool_var. */
11759 /* If this is an equality comparison of the address of two non-weak,
11760 unaliased symbols neither of which are extern (since we do not
11761 have access to attributes for externs), then we know the result. */
11774 {
11775 /* We know that we're looking at the address of two
11776 non-weak, unaliased, static _DECL nodes.
11778 It is both wasteful and incorrect to call operand_equal_p
11779 to compare the two ADDR_EXPR nodes. It is wasteful in that
11780 all we need to do is test pointer equality for the arguments
11781 to the two ADDR_EXPR nodes. It is incorrect to use
11782 operand_equal_p as that function is NOT equivalent to a
11783 C equality test. It can in fact return false for two
11784 objects which would test as equal using the C equality
11785 operator. */
11789 type);
11790 }
11792 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11793 a MINUS_EXPR of a constant, we can convert it into a comparison with
11794 a revised constant as long as no overflow occurs. */
11806 /* Similarly for a NEGATE_EXPR. */
11814 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11823 /* Transform comparisons of the form X +- C CMP X. */
11829 {
11836 else
11839 }
11841 /* If we have X - Y == 0, we can convert that to X == Y and similarly
11842 for !=. Don't do this for ordered comparisons due to overflow. */
11848 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11853 /* If this is an EQ or NE comparison with zero and ARG0 is
11854 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11855 two operations, but the latter can be done in one less insn
11856 on machines that have only two-operand insns or on which a
11857 constant cannot be the first operand. */
11860 {
11865 {
11872 }
11875 {
11882 }
11883 }
11885 /* If this is an NE or EQ comparison of zero against the result of a
11886 signed MOD operation whose second operand is a power of 2, make
11887 the MOD operation unsigned since it is simpler and equivalent. */
11895 {
11905 }
11907 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11908 C1 is a valid shift constant, and C2 is a power of two, i.e.
11909 a single bit. */
11913 == INTEGER_CST
11916 {
11921 /* Check for a valid shift count. */
11924 {
11928 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11929 can be rewritten as (X & (C2 << C1)) != 0. */
11931 {
11935 }
11936 /* Otherwise, for signed (arithmetic) shifts,
11937 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11938 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11942 /* Otherwise, of unsigned (logical) shifts,
11943 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11944 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11945 else
11949 arg000);
11950 }
11951 }
11953 /* If this is an NE comparison of zero with an AND of one, remove the
11954 comparison since the AND will give the correct value. */
11961 /* If we have (A & C) == C where C is a power of 2, convert this into
11962 (A & C) != 0. Similarly for NE_EXPR. */
11968 integer_zero_node));
11970 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
11971 bit, then fold the expression into A < 0 or A >= 0. */
11976 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
11977 Similarly for NE_EXPR. */
11981 {
11990 }
11992 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
11993 Similarly for NE_EXPR. */
11997 {
12004 }
12006 /* Optimize comparisons of strlen vs zero to a compare of the
12007 first character of the string vs zero. To wit,
12008 strlen(ptr) == 0 => *ptr == 0
12009 strlen(ptr) != 0 => *ptr != 0
12010 Other cases should reduce to one of these two (or a constant)
12011 due to the return value of strlen being unsigned. */
12014 {
12022 {
12026 }
12027 }
12029 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12030 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12034 {
12041 {
12043 {
12046 }
12049 }
12050 }
12052 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12058 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12063 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12070 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12078 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12079 (X & C) == 0 when C is a single bit. */
12084 {
12090 }
12092 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12093 constant C is a power of two, i.e. a single bit. */
12100 {
12104 }
12106 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12107 when is C is a power of two, i.e. a single bit. */
12114 {
12120 }
12124 {
12127 }
12129 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12136 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12139 {
12151 arg01),
12159 arg01),
12167 arg00),
12175 arg00),
12177 }
12181 {
12188 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12189 operand_equal_p guarantees no side-effects so we don't need
12190 to use omit_one_operand on Z. */
12200 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12207 arg10);
12208 }
12210 /* Attempt to simplify equality/inequality comparisons of complex
12211 values. Only lower the comparison if the result is known or
12212 can be simplified to a single scalar comparison. */
12217 {
12222 {
12225 }
12226 else
12227 {
12230 }
12233 {
12236 }
12237 else
12238 {
12241 }
12245 {
12247 {
12252 }
12253 else
12254 {
12259 }
12260 }
12264 {
12266 {
12271 }
12272 else
12273 {
12278 }
12279 }
12280 }
12292 /* Transform comparisons of the form X +- C CMP X. */
12299 {
12306 else
12309 /* (X - c) > X becomes false. */
12313 {
12317 "occur when assuming that (X - c) > X "
12319 WARN_STRICT_OVERFLOW_ALL);
12321 }
12323 /* Likewise (X + c) < X becomes false. */
12327 {
12331 "occur when assuming that "
12333 WARN_STRICT_OVERFLOW_ALL);
12335 }
12337 /* Convert (X - c) <= X to true. */
12342 {
12346 "occur when assuming that "
12348 WARN_STRICT_OVERFLOW_ALL);
12350 }
12352 /* Convert (X + c) >= X to true. */
12357 {
12361 "occur when assuming that "
12363 WARN_STRICT_OVERFLOW_ALL);
12365 }
12368 {
12369 /* Convert X + c > X and X - c < X to true for integers. */
12373 {
12376 "not occur when assuming that "
12378 WARN_STRICT_OVERFLOW_ALL);
12380 }
12385 {
12388 "not occur when assuming that "
12390 WARN_STRICT_OVERFLOW_ALL);
12392 }
12394 /* Convert X + c <= X and X - c >= X to false for integers. */
12398 {
12401 "not occur when assuming that "
12403 WARN_STRICT_OVERFLOW_ALL);
12405 }
12410 {
12413 "not occur when assuming that "
12415 WARN_STRICT_OVERFLOW_ALL);
12417 }
12418 }
12419 }
12421 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
12422 This transformation affects the cases which are handled in later
12423 optimizations involving comparisons with non-negative constants. */
12427 {
12429 {
12434 }
12436 {
12441 }
12442 }
12444 /* Comparisons with the highest or lowest possible integer of
12445 the specified precision will have known values. */
12446 {
12454 {
12455 HOST_WIDE_INT signed_max_hi;
12460 {
12467 {
12471 }
12472 else
12473 {
12477 }
12478 }
12479 else
12480 {
12489 {
12492 }
12493 else
12494 {
12497 }
12498 }
12503 {
12516 /* The GE_EXPR and LT_EXPR cases above are not normally
12517 reached because of previous transformations. */
12521 }
12523 == max_hi
12526 {
12532 arg1);
12538 arg1);
12541 }
12543 == min_hi
12546 {
12561 }
12563 == min_hi
12566 {
12571 arg1);
12576 arg1);
12579 }
12584 /* We will flip the signedness of the comparison operator
12585 associated with the mode of arg1, so the sign bit is
12586 specified by this mode. Check that arg1 is the signed
12587 max associated with this sign bit. */
12589 /* signed_type does not work on pointer types. */
12591 {
12592 /* The following case also applies to X < signed_max+1
12593 and X >= signed_max+1 because previous transformations. */
12595 {
12596 tree st;
12601 }
12602 }
12603 }
12604 }
12606 /* If we are comparing an ABS_EXPR with a constant, we can
12607 convert all the cases into explicit comparisons, but they may
12608 well not be faster than doing the ABS and one comparison.
12609 But ABS (X) <= C is a range comparison, which becomes a subtraction
12610 and a comparison, and is probably faster. */
12624 /* Convert ABS_EXPR<x> >= 0 to true. */
12631 {
12634 "when simplifying comparison of "
12636 WARN_STRICT_OVERFLOW_CONDITIONAL);
12638 }
12640 /* Convert ABS_EXPR<x> < 0 to false. */
12645 {
12648 "when simplifying comparison of "
12650 WARN_STRICT_OVERFLOW_CONDITIONAL);
12652 }
12654 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12655 and similarly for >= into !=. */
12670 return
12689 {
12693 }
12695 /* If the first operand is NaN, the result is constant. */
12699 {
12701 ? integer_zero_node
12704 }
12706 /* If the second operand is NaN, the result is constant. */
12710 {
12712 ? integer_zero_node
12715 }
12717 /* Simplify unordered comparison of something with itself. */
12723 && !flag_trapping_math
12727 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12728 {
12739 }
12744 /* When pedantic, a compound expression can be neither an lvalue
12745 nor an integer constant expression. */
12748 /* Don't let (0, 0) be null pointer constant. */
12762 /* An ASSERT_EXPR should never be passed to fold_binary. */
12768 }
12770 /* Callback for walk_tree, looking for LABEL_EXPR.
12771 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12772 Do not check the sub-tree of GOTO_EXPR. */
12774 static tree
12778 {
12780 {
12785 /* no break */
12788 }
12789 }
12791 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12792 accessible from outside the sub-tree. Returns NULL_TREE if no
12793 addressable label is found. */
12795 static bool
12797 {
12799 }
12801 /* Fold a ternary expression of code CODE and type TYPE with operands
12802 OP0, OP1, and OP2. Return the folded expression if folding is
12803 successful. Otherwise, return NULL_TREE. */
12805 tree
12807 {
12808 tree tem;
12815 /* Strip any conversions that don't change the mode. This is safe
12816 for every expression, except for a comparison expression because
12817 its signedness is derived from its operands. So, in the latter
12818 case, only strip conversions that don't change the signedness.
12820 Note that this is done as an internal manipulation within the
12821 constant folder, in order to find the simplest representation of
12822 the arguments so that their form can be studied. In any cases,
12823 the appropriate type conversions should be put back in the tree
12824 that will get out of the constant folder. */
12826 {
12829 }
12832 {
12835 }
12838 {
12842 {
12848 }
12852 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12853 so all simple results must be passed through pedantic_non_lvalue. */
12855 {
12858 /* Only optimize constant conditions when the selected branch
12859 has the same type as the COND_EXPR. This avoids optimizing
12860 away "c ? x : throw", where the throw has a void type.
12861 Avoid throwing away that operand which contains label. */
12868 }
12872 /* If we have A op B ? A : C, we may be able to convert this to a
12873 simpler expression, depending on the operation and the values
12874 of B and C. Signed zeros prevent all of these transformations,
12875 for reasons given above each one.
12877 Also try swapping the arguments and inverting the conditional. */
12882 {
12886 }
12890 op2,
12893 {
12896 {
12900 }
12901 }
12903 /* If the second operand is simpler than the third, swap them
12904 since that produces better jump optimization results. */
12907 {
12908 /* See if this can be inverted. If it can't, possibly because
12909 it was a floating-point inequality comparison, don't do
12910 anything. */
12914 }
12916 /* Convert A ? 1 : 0 to simply A. */
12919 /* If we try to convert OP0 to our type, the
12920 call to fold will try to move the conversion inside
12921 a COND, which will recurse. In that case, the COND_EXPR
12922 is probably the best choice, so leave it alone. */
12926 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12927 over COND_EXPR in cases such as floating point comparisons. */
12934 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12939 {
12940 /* sign_bit_p only checks ARG1 bits within A's precision.
12941 If <sign bit of A> has wider type than A, bits outside
12942 of A's precision in <sign bit of A> need to be checked.
12943 If they are all 0, this optimization needs to be done
12944 in unsigned A's type, if they are all 1 in signed A's type,
12945 otherwise this can't be done. */
12950 {
12952 HOST_WIDE_INT mask_hi;
12954 tree tem_type;
12962 {
12966 }
12967 else
12968 {
12972 }
12974 {
12978 }
12979 else
12985 {
12988 }
12991 {
12994 }
12995 else
12997 }
13004 arg1)));
13005 }
13007 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13008 already handled above. */
13013 {
13022 }
13024 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13025 is probably obsolete because the first operand should be a
13026 truth value (that's why we have the two cases above), but let's
13027 leave it in until we can confirm this for all front-ends. */
13038 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13044 arg1);
13046 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13050 {
13051 /* Only perform transformation if ARG0 is easily inverted. */
13056 arg1);
13057 }
13059 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13063 {
13064 /* Only perform transformation if ARG0 is easily inverted. */
13069 op2);
13070 }
13072 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13078 op2);
13083 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13084 of fold_ternary on them. */
13091 {
13100 {
13105 else
13106 {
13108 tree value;
13112 }
13117 else
13119 }
13120 }
13122 /* A bit-field-ref that referenced the full argument can be stripped. */
13133 }
13135 /* Perform constant folding and related simplification of EXPR.
13136 The related simplifications include x*1 => x, x*0 => 0, etc.,
13137 and application of the associative law.
13138 NOP_EXPR conversions may be removed freely (as long as we
13139 are careful not to change the type of the overall expression).
13140 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13141 but we can constant-fold them if they have constant operands. */
13143 #ifdef ENABLE_FOLD_CHECKING
13144 # define fold(x) fold_1 (x)
13146 static
13147 #endif
13148 tree
13150 {
13154 tree tem;
13156 /* Return right away if a constant. */
13160 /* CALL_EXPR-like objects with variable numbers of operands are
13161 treated specially. */
13163 {
13165 {
13168 }
13170 }
13174 {
13179 {
13197 }
13198 }
13201 {
13203 {
13210 {
13215 /* Find a matching index by means of a binary search. */
13217 {
13233 else
13235 }
13236 }
13239 }
13247 }
13249 #ifdef ENABLE_FOLD_CHECKING
13250 #undef fold
13256 /* When --enable-checking=fold, compute a digest of expr before
13257 and after actual fold call to see if fold did not accidentally
13258 change original expr. */
13260 tree
13262 {
13263 tree ret;
13266 htab_t ht;
13285 }
13287 void
13289 {
13292 htab_t ht;
13302 }
13304 static void
13306 {
13308 }
13310 static void
13312 {
13318 recursive_label:
13332 {
13333 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13337 }
13342 {
13343 /* Allow these fields to be modified. */
13344 tree tmp;
13351 {
13354 }
13355 }
13364 {
13367 {
13381 }
13385 {
13398 }
13415 {
13421 }
13426 {
13430 }
13441 {
13444 }
13454 }
13455 }
13457 /* Helper function for outputting the checksum of a tree T. When
13458 debugging with gdb, you can "define mynext" to be "next" followed
13459 by "call debug_fold_checksum (op0)", then just trace down till the
13460 outputs differ. */
13462 void
13464 {
13479 }
13481 #endif
13483 /* Fold a unary tree expression with code CODE of type TYPE with an
13484 operand OP0. Return a folded expression if successful. Otherwise,
13485 return a tree expression with code CODE of type TYPE with an
13486 operand OP0. */
13488 tree
13490 {
13491 tree tem;
13492 #ifdef ENABLE_FOLD_CHECKING
13495 htab_t ht;
13502 #endif
13508 #ifdef ENABLE_FOLD_CHECKING
13516 #endif
13518 }
13520 /* Fold a binary tree expression with code CODE of type TYPE with
13521 operands OP0 and OP1. Return a folded expression if successful.
13522 Otherwise, return a tree expression with code CODE of type TYPE
13523 with operands OP0 and OP1. */
13525 tree
13527 MEM_STAT_DECL)
13528 {
13529 tree tem;
13530 #ifdef ENABLE_FOLD_CHECKING
13536 htab_t ht;
13548 #endif
13554 #ifdef ENABLE_FOLD_CHECKING
13570 #endif
13572 }
13574 /* Fold a ternary tree expression with code CODE of type TYPE with
13575 operands OP0, OP1, and OP2. Return a folded expression if
13576 successful. Otherwise, return a tree expression with code CODE of
13577 type TYPE with operands OP0, OP1, and OP2. */
13579 tree
13581 MEM_STAT_DECL)
13582 {
13583 tree tem;
13584 #ifdef ENABLE_FOLD_CHECKING
13592 htab_t ht;
13609 #endif
13616 #ifdef ENABLE_FOLD_CHECKING
13640 #endif
13642 }
13644 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13645 arguments in ARGARRAY, and a null static chain.
13646 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13647 of type TYPE from the given operands as constructed by build_call_array. */
13649 tree
13651 {
13652 tree tem;
13653 #ifdef ENABLE_FOLD_CHECKING
13659 htab_t ht;
13673 #endif
13677 #ifdef ENABLE_FOLD_CHECKING
13694 #endif
13696 }
13698 /* Perform constant folding and related simplification of initializer
13699 expression EXPR. These behave identically to "fold_buildN" but ignore
13700 potential run-time traps and exceptions that fold must preserve. */
13702 #define START_FOLD_INIT \
13703 int saved_signaling_nans = flag_signaling_nans;\
13704 int saved_trapping_math = flag_trapping_math;\
13705 int saved_rounding_math = flag_rounding_math;\
13706 int saved_trapv = flag_trapv;\
13707 int saved_folding_initializer = folding_initializer;\
13708 flag_signaling_nans = 0;\
13709 flag_trapping_math = 0;\
13710 flag_rounding_math = 0;\
13711 flag_trapv = 0;\
13712 folding_initializer = 1;
13714 #define END_FOLD_INIT \
13715 flag_signaling_nans = saved_signaling_nans;\
13716 flag_trapping_math = saved_trapping_math;\
13717 flag_rounding_math = saved_rounding_math;\
13718 flag_trapv = saved_trapv;\
13719 folding_initializer = saved_folding_initializer;
13721 tree
13723 {
13724 tree result;
13725 START_FOLD_INIT;
13729 END_FOLD_INIT;
13731 }
13733 tree
13735 {
13736 tree result;
13737 START_FOLD_INIT;
13741 END_FOLD_INIT;
13743 }
13745 tree
13747 tree op2)
13748 {
13749 tree result;
13750 START_FOLD_INIT;
13754 END_FOLD_INIT;
13756 }
13758 tree
13761 {
13762 tree result;
13763 START_FOLD_INIT;
13767 END_FOLD_INIT;
13769 }
13771 #undef START_FOLD_INIT
13772 #undef END_FOLD_INIT
13774 /* Determine if first argument is a multiple of second argument. Return 0 if
13775 it is not, or we cannot easily determined it to be.
13777 An example of the sort of thing we care about (at this point; this routine
13778 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13779 fold cases do now) is discovering that
13781 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13783 is a multiple of
13785 SAVE_EXPR (J * 8)
13787 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13789 This code also handles discovering that
13791 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13793 is a multiple of 8 so we don't have to worry about dealing with a
13794 possible remainder.
13796 Note that we *look* inside a SAVE_EXPR only to determine how it was
13797 calculated; it is not safe for fold to do much of anything else with the
13798 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13799 at run time. For example, the latter example above *cannot* be implemented
13800 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13801 evaluation time of the original SAVE_EXPR is not necessarily the same at
13802 the time the new expression is evaluated. The only optimization of this
13803 sort that would be valid is changing
13805 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13807 divided by 8 to
13809 SAVE_EXPR (I) * SAVE_EXPR (J)
13811 (where the same SAVE_EXPR (J) is used in the original and the
13812 transformed version). */
13814 int
13816 {
13824 {
13826 /* Bitwise and provides a power of two multiple. If the mask is
13827 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13830 /* FALLTHRU */
13843 {
13847 /* const_binop may not detect overflow correctly,
13848 so check for it explicitly here. */
13854 size_one_node,
13858 }
13862 /* Can't handle conversions from non-integral or wider integral type. */
13868 /* .. fall through ... */
13885 }
13886 }
13888 /* Return true if CODE or TYPE is known to be non-negative. */
13890 static bool
13892 {
13895 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13896 have a signed:1 type (where the value is -1 and 0). */
13899 }
13901 /* Return true if (CODE OP0) is known to be non-negative. If the return
13902 value is based on the assumption that signed overflow is undefined,
13903 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13904 *STRICT_OVERFLOW_P. */
13906 bool
13909 {
13914 {
13916 /* We can't return 1 if flag_wrapv is set because
13917 ABS_EXPR<INT_MIN> = INT_MIN. */
13921 {
13924 }
13931 strict_overflow_p);
13934 {
13939 {
13942 strict_overflow_p);
13944 {
13948 strict_overflow_p);
13949 }
13950 }
13952 {
13955 strict_overflow_p);
13959 }
13960 }
13965 }
13967 /* We don't know sign of `t', so be conservative and return false. */
13969 }
13971 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13972 value is based on the assumption that signed overflow is undefined,
13973 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13974 *STRICT_OVERFLOW_P. */
13976 bool
13979 {
13984 {
13989 strict_overflow_p)
13991 strict_overflow_p));
13993 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13994 both unsigned and at least 2 bits shorter than the result. */
13998 {
14003 {
14007 }
14008 }
14013 {
14014 /* x * x for floating point x is always non-negative. */
14018 strict_overflow_p)
14020 strict_overflow_p));
14021 }
14023 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14024 both unsigned and their total bits is shorter than the result. */
14028 {
14035 }
14041 strict_overflow_p)
14043 strict_overflow_p));
14054 strict_overflow_p)
14056 strict_overflow_p));
14063 strict_overflow_p);
14066 }
14068 /* We don't know sign of `t', so be conservative and return false. */
14070 }
14072 /* Return true if T is known to be non-negative. If the return
14073 value is based on the assumption that signed overflow is undefined,
14074 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14075 *STRICT_OVERFLOW_P. */
14077 bool
14079 {
14084 {
14096 strict_overflow_p)
14098 strict_overflow_p));
14102 }
14103 /* We don't know sign of `t', so be conservative and return false. */
14105 }
14107 /* Return true if T is known to be non-negative. If the return
14108 value is based on the assumption that signed overflow is undefined,
14109 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14110 *STRICT_OVERFLOW_P. */
14112 bool
14115 {
14118 {
14136 /* Always true. */
14140 /* sqrt(-0.0) is -0.0. */
14144 strict_overflow_p);
14177 /* True if the 1st argument is nonnegative. */
14179 strict_overflow_p);
14182 /* True if the 1st OR 2nd arguments are nonnegative. */
14184 strict_overflow_p)
14186 strict_overflow_p)));
14189 /* True if the 1st AND 2nd arguments are nonnegative. */
14191 strict_overflow_p)
14193 strict_overflow_p)));
14196 /* True if the 2nd argument is nonnegative. */
14198 strict_overflow_p);
14201 /* True if the 1st argument is nonnegative or the second
14202 argument is an even integer. */
14207 strict_overflow_p);
14210 /* True if the 1st argument is nonnegative or the second
14211 argument is an even integer valued real. */
14213 {
14214 REAL_VALUE_TYPE c;
14215 HOST_WIDE_INT n;
14220 {
14221 REAL_VALUE_TYPE cint;
14226 }
14227 }
14229 strict_overflow_p);
14233 }
14235 type);
14236 }
14238 /* Return true if T is known to be non-negative. If the return
14239 value is based on the assumption that signed overflow is undefined,
14240 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14241 *STRICT_OVERFLOW_P. */
14243 bool
14245 {
14251 {
14253 {
14257 /* If the initializer is non-void, then it's a normal expression
14258 that will be assigned to the slot. */
14262 /* Otherwise, the initializer sets the slot in some way. One common
14263 way is an assignment statement at the end of the initializer. */
14265 {
14273 else
14275 }
14280 strict_overflow_p);
14283 }
14286 {
14293 arg0,
14294 arg1,
14295 strict_overflow_p);
14296 }
14301 strict_overflow_p);
14304 strict_overflow_p);
14307 strict_overflow_p);
14312 }
14314 /* We don't know sign of `t', so be conservative and return false. */
14316 }
14318 /* Return true if T is known to be non-negative. If the return
14319 value is based on the assumption that signed overflow is undefined,
14320 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14321 *STRICT_OVERFLOW_P. */
14323 bool
14325 {
14332 {
14339 strict_overflow_p);
14345 strict_overflow_p);
14354 }
14357 {
14365 strict_overflow_p);
14370 strict_overflow_p);
14385 }
14386 }
14388 /* Return true if `t' is known to be non-negative. Handle warnings
14389 about undefined signed overflow. */
14391 bool
14393 {
14400 "determining that expression is always "
14402 WARN_STRICT_OVERFLOW_MISC);
14404 }
14407 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14408 For floating point we further ensure that T is not denormal.
14409 Similar logic is present in nonzero_address in rtlanal.h.
14411 If the return value is based on the assumption that signed overflow
14412 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14413 change *STRICT_OVERFLOW_P. */
14415 bool
14418 {
14420 {
14423 strict_overflow_p);
14426 {
14432 strict_overflow_p));
14433 }
14438 strict_overflow_p);
14442 }
14445 }
14447 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14448 For floating point we further ensure that T is not denormal.
14449 Similar logic is present in nonzero_address in rtlanal.h.
14451 If the return value is based on the assumption that signed overflow
14452 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14453 change *STRICT_OVERFLOW_P. */
14455 bool
14457 tree type,
14458 tree op0,
14460 {
14463 {
14467 {
14468 /* With the presence of negative values it is hard
14469 to say something. */
14476 /* One of operands must be positive and the other non-negative. */
14477 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14478 overflows, on a twos-complement machine the sum of two
14479 nonnegative numbers can never be zero. */
14481 strict_overflow_p)
14483 strict_overflow_p));
14484 }
14489 {
14491 strict_overflow_p)
14493 strict_overflow_p))
14494 {
14497 }
14498 }
14507 {
14510 }
14517 {
14521 /* When both operands are nonzero, then MAX must be too. */
14523 strict_overflow_p))
14526 /* MAX where operand 0 is positive is positive. */
14528 strict_overflow_p);
14529 }
14530 /* MAX where operand 1 is positive is positive. */
14535 {
14539 }
14544 strict_overflow_p)
14546 strict_overflow_p));
14550 }
14553 }
14555 /* Return true when T is an address and is known to be nonzero.
14556 For floating point we further ensure that T is not denormal.
14557 Similar logic is present in nonzero_address in rtlanal.h.
14559 If the return value is based on the assumption that signed overflow
14560 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14561 change *STRICT_OVERFLOW_P. */
14563 bool
14565 {
14568 {
14573 {
14579 /* Weak declarations may link to NULL. */
14583 /* Constants are never weak. */
14588 }
14596 {
14600 }
14605 }
14607 }
14609 /* Return true when T is an address and is known to be nonzero.
14610 For floating point we further ensure that T is not denormal.
14611 Similar logic is present in nonzero_address in rtlanal.h.
14613 If the return value is based on the assumption that signed overflow
14614 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14615 change *STRICT_OVERFLOW_P. */
14617 bool
14619 {
14623 /* Doing something useful for floating point would need more work. */
14629 {
14632 strict_overflow_p);
14638 strict_overflow_p);
14646 }
14649 {
14652 strict_overflow_p);
14660 strict_overflow_p);
14678 strict_overflow_p);
14682 strict_overflow_p);
14689 }
14691 }
14693 /* Return true when T is an address and is known to be nonzero.
14694 Handle warnings about undefined signed overflow. */
14696 bool
14698 {
14705 "determining that expression is always "
14707 WARN_STRICT_OVERFLOW_MISC);
14709 }
14711 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14712 attempt to fold the expression to a constant without modifying TYPE,
14713 OP0 or OP1.
14715 If the expression could be simplified to a constant, then return
14716 the constant. If the expression would not be simplified to a
14717 constant, then return NULL_TREE. */
14719 tree
14721 {
14724 }
14726 /* Given the components of a unary expression CODE, TYPE and OP0,
14727 attempt to fold the expression to a constant without modifying
14728 TYPE or OP0.
14730 If the expression could be simplified to a constant, then return
14731 the constant. If the expression would not be simplified to a
14732 constant, then return NULL_TREE. */
14734 tree
14736 {
14739 }
14741 /* If EXP represents referencing an element in a constant string
14742 (either via pointer arithmetic or array indexing), return the
14743 tree representing the value accessed, otherwise return NULL. */
14745 tree
14747 {
14751 {
14753 tree index;
14754 tree string;
14758 else
14759 {
14763 /* Optimize the special-case of a zero lower bound.
14765 We convert the low_bound to sizetype to avoid some problems
14766 with constant folding. (E.g. suppose the lower bound is 1,
14767 and its mode is QI. Without the conversion,l (ARRAY
14768 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14769 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
14774 }
14787 }
14789 }
14791 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14792 an integer constant, real, or fixed-point constant.
14794 TYPE is the type of the result. */
14796 static tree
14798 {
14802 {
14804 {
14806 HOST_WIDE_INT high;
14814 }
14821 {
14822 FIXED_VALUE_TYPE f;
14827 /* Propagate overflow flags. */
14829 {
14832 }
14836 }
14840 }
14843 }
14845 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14846 an integer constant or real constant.
14848 TYPE is the type of the result. */
14850 tree
14852 {
14856 {
14858 /* If the value is unsigned, then the absolute value is
14859 the same as the ordinary value. */
14862 /* Similarly, if the value is non-negative. */
14865 /* If the value is negative, then the absolute value is
14866 its negation. */
14867 else
14868 {
14870 HOST_WIDE_INT high;
14876 }
14882 else
14888 }
14891 }
14893 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14894 constant. TYPE is the type of the result. */
14896 static tree
14898 {
14908 }
14910 /* Given CODE, a relational operator, the target type, TYPE and two
14911 constant operands OP0 and OP1, return the result of the
14912 relational operation. If the result is not a compile time
14913 constant, then return NULL_TREE. */
14915 static tree
14917 {
14920 /* From here on, the only cases we handle are when the result is
14921 known to be a constant. */
14924 {
14928 /* Handle the cases where either operand is a NaN. */
14930 {
14932 {
14960 }
14963 }
14966 }
14969 {
14973 }
14975 /* Handle equality/inequality of complex constants. */
14977 {
14988 else
14990 }
14992 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14994 To compute GT, swap the arguments and do LT.
14995 To compute GE, do LT and invert the result.
14996 To compute LE, swap the arguments, do LT and invert the result.
14997 To compute NE, do EQ and invert the result.
14999 Therefore, the code below must handle only EQ and LT. */
15002 {
15007 }
15009 /* Note that it is safe to invert for real values here because we
15010 have already handled the one case that it matters. */
15014 {
15017 }
15019 /* Compute a result for LT or EQ if args permit;
15020 Otherwise return T. */
15022 {
15027 else
15029 }
15030 else
15036 }
15038 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15039 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15040 itself. */
15042 tree
15044 {
15045 /* If the expression does not have side effects then we don't have to wrap
15046 it with a cleanup point expression. */
15050 /* If the expression is a return, check to see if the expression inside the
15051 return has no side effects or the right hand side of the modify expression
15052 inside the return. If either don't have side effects set we don't need to
15053 wrap the expression in a cleanup point expression. Note we don't check the
15054 left hand side of the modify because it should always be a return decl. */
15056 {
15063 }
15066 }
15068 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15069 of an indirection through OP0, or NULL_TREE if no simplification is
15070 possible. */
15072 tree
15074 {
15076 tree subtype;
15084 {
15087 /* *&CONST_DECL -> to the value of the const decl. */
15090 /* *&p => p; make sure to handle *&"str"[cst] here. */
15092 {
15096 else
15098 }
15099 /* *(foo *)&fooarray => fooarray[0] */
15102 {
15108 }
15109 /* *(foo *)&complexfoo => __real__ complexfoo */
15113 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15116 {
15120 }
15121 }
15123 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15126 {
15129 tree op00type;
15136 {
15147 }
15148 }
15151 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15154 {
15157 tree op00type;
15164 {
15168 }
15169 }
15171 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15174 {
15175 tree type_domain;
15182 }
15185 }
15187 /* Builds an expression for an indirection through T, simplifying some
15188 cases. */
15190 tree
15192 {
15198 else
15200 }
15202 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15204 tree
15206 {
15211 else
15213 }
15215 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15216 whose result is ignored. The type of the returned tree need not be
15217 the same as the original expression. */
15219 tree
15221 {
15227 {
15238 else
15244 {
15260 }
15265 }
15266 }
15268 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15269 This can only be applied to objects of a sizetype. */
15271 tree
15273 {
15280 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15281 have to do anything. Only do this when we are not given a const,
15282 because in that case, this check is more expensive than just
15283 doing it. */
15285 {
15290 }
15292 /* If divisor is a power of two, simplify this to bit manipulation. */
15294 {
15296 {
15309 {
15310 high++;
15313 }
15317 }
15318 else
15319 {
15320 tree t;
15326 }
15327 }
15328 else
15329 {
15334 }
15337 }
15339 /* Likewise, but round down. */
15341 tree
15343 {
15350 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15351 have to do anything. Only do this when we are not given a const,
15352 because in that case, this check is more expensive than just
15353 doing it. */
15355 {
15360 }
15362 /* If divisor is a power of two, simplify this to bit manipulation. */
15364 {
15365 tree t;
15369 }
15370 else
15371 {
15376 }
15379 }
15381 /* Returns the pointer to the base of the object addressed by EXP and
15382 extracts the information about the offset of the access, storing it
15383 to PBITPOS and POFFSET. */
15385 static tree
15388 {
15389 tree core;
15392 HOST_WIDE_INT bitsize;
15395 {
15400 }
15401 else
15402 {
15406 }
15409 }
15411 /* Returns true if addresses of E1 and E2 differ by a constant, false
15412 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15414 bool
15416 {
15430 {
15440 }
15442 {
15443 /* If only one of the offsets is non-constant, the difference cannot
15444 be a constant. */
15446 }
15447 else
15452 }
15454 /* Simplify the floating point expression EXP when the sign of the
15455 result is not significant. Return NULL_TREE if no simplification
15456 is possible. */
15458 tree
15460 {
15464 {
15499 {
15502 {
15504 /* Strip copysign function call, return the 1st argument. */
15510 /* Strip sign ops from the argument of "odd" math functions. */
15512 {
15516 }
15518 }
15519 }
15524 }
15526 }