| blob | c167bc4f6706ae3fe8b86c16a46bc8c12c0a58ae |
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 {
2400 {
2407 }
2409 {
2416 }
2418 {
2425 }
2427 }
2429 /* Construct a vector of zero elements of vector type TYPE. */
2431 static tree
2433 {
2444 }
2446 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2448 bool
2450 {
2465 {
2484 }
2485 }
2487 /* Convert expression ARG to type TYPE. Used by the middle-end for
2488 simple conversions in preference to calling the front-end's convert. */
2490 tree
2492 {
2494 tree tem;
2508 {
2513 {
2517 }
2522 {
2525 }
2532 {
2536 }
2538 {
2542 }
2544 {
2548 }
2551 {
2569 }
2574 {
2578 }
2581 {
2595 }
2599 {
2609 {
2613 {
2617 }
2625 }
2629 }
2647 }
2648 }
2649 \f
2650 /* Return false if expr can be assumed not to be an lvalue, true
2651 otherwise. */
2653 static bool
2655 {
2656 /* We only need to wrap lvalue tree codes. */
2658 {
2693 /* Assume the worst for front-end tree codes. */
2697 }
2700 }
2702 /* Return an expr equal to X but certainly not valid as an lvalue. */
2704 tree
2706 {
2707 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2708 us. */
2715 }
2717 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2718 Zero means allow extended lvalues. */
2722 /* When pedantic, return an expr equal to X but certainly not valid as a
2723 pedantic lvalue. Otherwise, return X. */
2725 static tree
2727 {
2730 else
2732 }
2733 \f
2734 /* Given a tree comparison code, return the code that is the logical inverse
2735 of the given code. It is not safe to do this for floating-point
2736 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2737 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2739 enum tree_code
2741 {
2746 {
2777 }
2778 }
2780 /* Similar, but return the comparison that results if the operands are
2781 swapped. This is safe for floating-point. */
2783 enum tree_code
2785 {
2787 {
2813 }
2814 }
2817 /* Convert a comparison tree code from an enum tree_code representation
2818 into a compcode bit-based encoding. This function is the inverse of
2819 compcode_to_comparison. */
2821 static enum comparison_code
2823 {
2825 {
2856 }
2857 }
2859 /* Convert a compcode bit-based encoding of a comparison operator back
2860 to GCC's enum tree_code representation. This function is the
2861 inverse of comparison_to_compcode. */
2863 static enum tree_code
2865 {
2867 {
2898 }
2899 }
2901 /* Return a tree for the comparison which is the combination of
2902 doing the AND or OR (depending on CODE) of the two operations LCODE
2903 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2904 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2905 if this makes the transformation invalid. */
2907 tree
2911 {
2918 {
2929 }
2932 {
2933 /* Eliminate unordered comparisons, as well as LTGT and ORD
2934 which are not used unless the mode has NaNs. */
2940 }
2942 {
2943 /* Check that the original operation and the optimized ones will trap
2944 under the same condition. */
2955 /* In a short-circuited boolean expression the LHS might be
2956 such that the RHS, if evaluated, will never trap. For
2957 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2958 if neither x nor y is NaN. (This is a mixed blessing: for
2959 example, the expression above will never trap, hence
2960 optimizing it to x < y would be invalid). */
2965 /* If the comparison was short-circuited, and only the RHS
2966 trapped, we may now generate a spurious trap. */
2971 /* If we changed the conditions that cause a trap, we lose. */
2974 }
2980 else
2983 }
2985 /* Return nonzero if CODE is a tree code that represents a truth value. */
2987 static int
2989 {
2994 }
2995 \f
2996 /* Return nonzero if two operands (typically of the same tree node)
2997 are necessarily equal. If either argument has side-effects this
2998 function returns zero. FLAGS modifies behavior as follows:
3000 If OEP_ONLY_CONST is set, only return nonzero for constants.
3001 This function tests whether the operands are indistinguishable;
3002 it does not test whether they are equal using C's == operation.
3003 The distinction is important for IEEE floating point, because
3004 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3005 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3007 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3008 even though it may hold multiple values during a function.
3009 This is because a GCC tree node guarantees that nothing else is
3010 executed between the evaluation of its "operands" (which may often
3011 be evaluated in arbitrary order). Hence if the operands themselves
3012 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3013 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3014 unset means assuming isochronic (or instantaneous) tree equivalence.
3015 Unless comparing arbitrary expression trees, such as from different
3016 statements, this flag can usually be left unset.
3018 If OEP_PURE_SAME is set, then pure functions with identical arguments
3019 are considered the same. It is used when the caller has other ways
3020 to ensure that global memory is unchanged in between. */
3022 int
3024 {
3025 /* If either is ERROR_MARK, they aren't equal. */
3029 /* Check equality of integer constants before bailing out due to
3030 precision differences. */
3034 /* If both types don't have the same signedness, then we can't consider
3035 them equal. We must check this before the STRIP_NOPS calls
3036 because they may change the signedness of the arguments. As pointers
3037 strictly don't have a signedness, require either two pointers or
3038 two non-pointers as well. */
3043 /* If both types don't have the same precision, then it is not safe
3044 to strip NOPs. */
3051 /* In case both args are comparisons but with different comparison
3052 code, try to swap the comparison operands of one arg to produce
3053 a match and compare that variant. */
3057 {
3065 }
3068 /* This is needed for conversions and for COMPONENT_REF.
3069 Might as well play it safe and always test this. */
3075 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3076 We don't care about side effects in that case because the SAVE_EXPR
3077 takes care of that for us. In all other cases, two expressions are
3078 equal if they have no side effects. If we have two identical
3079 expressions with side effects that should be treated the same due
3080 to the only side effects being identical SAVE_EXPR's, that will
3081 be detected in the recursive calls below. */
3087 /* Next handle constant cases, those for which we can return 1 even
3088 if ONLY_CONST is set. */
3091 {
3106 {
3107 /* If we do not distinguish between signed and unsigned zero,
3108 consider them equal. */
3111 }
3115 {
3121 {
3123 flags))
3127 }
3130 }
3134 flags)
3136 flags));
3149 }
3154 /* Define macros to test an operand from arg0 and arg1 for equality and a
3155 variant that allows null and views null as being different from any
3156 non-null value. In the latter case, if either is null, the both
3157 must be; otherwise, do the normal comparison. */
3158 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3159 TREE_OPERAND (arg1, N), flags)
3161 #define OP_SAME_WITH_NULL(N) \
3162 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3163 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3166 {
3168 /* Two conversions are equal only if signedness and modes match. */
3170 {
3171 CASE_CONVERT:
3179 }
3189 /* For commutative ops, allow the other order. */
3197 /* If either of the pointer (or reference) expressions we are
3198 dereferencing contain a side effect, these cannot be equal. */
3204 {
3214 /* Operands 2 and 3 may be null.
3215 Compare the array index by value if it is constant first as we
3216 may have different types but same value here. */
3225 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3226 may be NULL when we're called to compare MEM_EXPRs. */
3236 }
3240 {
3255 /* Otherwise take into account this is a commutative operation. */
3263 }
3267 {
3269 /* If the CALL_EXPRs call different functions, then they
3270 clearly can not be equal. */
3272 flags))
3275 {
3279 else
3283 }
3285 /* Now see if all the arguments are the same. */
3286 {
3297 /* If we get here and both argument lists are exhausted
3298 then the CALL_EXPRs are equal. */
3300 }
3303 }
3306 /* Consider __builtin_sqrt equal to sqrt. */
3314 }
3316 #undef OP_SAME
3317 #undef OP_SAME_WITH_NULL
3318 }
3319 \f
3320 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3321 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3323 When in doubt, return 0. */
3325 static int
3327 {
3339 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3340 and see if the inner values are the same. This removes any
3341 signedness comparison, which doesn't matter here. */
3348 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3349 actual comparison operand, ARG0.
3351 First throw away any conversions to wider types
3352 already present in the operands. */
3361 {
3364 /* Make sure shorter operand is extended the right way
3365 to match the longer operand. */
3371 }
3374 }
3375 \f
3376 /* See if ARG is an expression that is either a comparison or is performing
3377 arithmetic on comparisons. The comparisons must only be comparing
3378 two different values, which will be stored in *CVAL1 and *CVAL2; if
3379 they are nonzero it means that some operands have already been found.
3380 No variables may be used anywhere else in the expression except in the
3381 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3382 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3384 If this is true, return 1. Otherwise, return zero. */
3386 static int
3388 {
3392 /* We can handle some of the tcc_expression cases here. */
3402 {
3403 /* If we've already found a CVAL1 or CVAL2, this expression is
3404 two complex to handle. */
3410 }
3413 {
3436 /* First see if we can handle the first operand, then the second. For
3437 the second operand, we know *CVAL1 can't be zero. It must be that
3438 one side of the comparison is each of the values; test for the
3439 case where this isn't true by failing if the two operands
3440 are the same. */
3449 ;
3453 ;
3454 else
3458 ;
3462 ;
3463 else
3470 }
3471 }
3472 \f
3473 /* ARG is a tree that is known to contain just arithmetic operations and
3474 comparisons. Evaluate the operations in the tree substituting NEW0 for
3475 any occurrence of OLD0 as an operand of a comparison and likewise for
3476 NEW1 and OLD1. */
3478 static tree
3480 {
3485 /* We can handle some of the tcc_expression cases here. */
3493 {
3508 {
3525 }
3526 /* Fall through - ??? */
3529 {
3533 /* We need to check both for exact equality and tree equality. The
3534 former will be true if the operand has a side-effect. In that
3535 case, we know the operand occurred exactly once. */
3548 }
3552 }
3553 }
3554 \f
3555 /* Return a tree for the case when the result of an expression is RESULT
3556 converted to TYPE and OMITTED was previously an operand of the expression
3557 but is now not needed (e.g., we folded OMITTED * 0).
3559 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3560 the conversion of RESULT to TYPE. */
3562 tree
3564 {
3567 /* If the resulting operand is an empty statement, just return the omitted
3568 statement casted to void. */
3576 }
3578 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3580 static tree
3582 {
3585 /* If the resulting operand is an empty statement, just return the omitted
3586 statement casted to void. */
3594 }
3596 /* Return a tree for the case when the result of an expression is RESULT
3597 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3598 of the expression but are now not needed.
3600 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3601 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3602 evaluated before OMITTED2. Otherwise, if neither has side effects,
3603 just do the conversion of RESULT to TYPE. */
3605 tree
3607 {
3616 }
3618 \f
3619 /* Return a simplified tree node for the truth-negation of ARG. This
3620 never alters ARG itself. We assume that ARG is an operation that
3621 returns a truth value (0 or 1).
3623 FIXME: one would think we would fold the result, but it causes
3624 problems with the dominator optimizer. */
3626 tree
3628 {
3632 /* If this is a comparison, we can simply invert it, except for
3633 floating-point non-equality comparisons, in which case we just
3634 enclose a TRUTH_NOT_EXPR around what we have. */
3637 {
3640 && flag_trapping_math
3644 else
3645 {
3650 else
3653 }
3654 }
3657 {
3672 /* Here we can invert either operand. We invert the first operand
3673 unless the second operand is a TRUTH_NOT_EXPR in which case our
3674 result is the XOR of the first operand with the inside of the
3675 negation of the second operand. */
3680 else
3699 {
3702 /* A COND_EXPR may have a throw as one operand, which
3703 then has void type. Just leave void operands
3704 as they are. */
3710 }
3743 }
3746 }
3748 /* Return a simplified tree node for the truth-negation of ARG. This
3749 never alters ARG itself. We assume that ARG is an operation that
3750 returns a truth value (0 or 1).
3752 FIXME: one would think we would fold the result, but it causes
3753 problems with the dominator optimizer. */
3755 tree
3757 {
3758 tree tem;
3768 }
3770 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3771 operands are another bit-wise operation with a common input. If so,
3772 distribute the bit operations to save an operation and possibly two if
3773 constants are involved. For example, convert
3774 (A | B) & (A | C) into A | (B & C)
3775 Further simplification will occur if B and C are constants.
3777 If this optimization cannot be done, 0 will be returned. */
3779 static tree
3781 {
3782 tree common;
3792 {
3796 }
3798 {
3802 }
3804 {
3808 }
3810 {
3814 }
3815 else
3820 }
3822 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3823 with code CODE. This optimization is unsafe. */
3824 static tree
3826 {
3830 /* (A / C) +- (B / C) -> (A +- B) / C. */
3840 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3845 {
3857 }
3860 }
3861 \f
3862 /* Subroutine for fold_truthop: decode a field reference.
3864 If EXP is a comparison reference, we return the innermost reference.
3866 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3867 set to the starting bit number.
3869 If the innermost field can be completely contained in a mode-sized
3870 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3872 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3873 otherwise it is not changed.
3875 *PUNSIGNEDP is set to the signedness of the field.
3877 *PMASK is set to the mask used. This is either contained in a
3878 BIT_AND_EXPR or derived from the width of the field.
3880 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3882 Return 0 if this is not a component reference or is one that we can't
3883 do anything with. */
3885 static tree
3890 {
3894 tree unsigned_type;
3897 /* All the optimizations using this function assume integer fields.
3898 There are problems with FP fields since the type_for_size call
3899 below can fail for, e.g., XFmode. */
3903 /* We are interested in the bare arrangement of bits, so strip everything
3904 that doesn't affect the machine mode. However, record the type of the
3905 outermost expression if it may matter below. */
3912 {
3918 }
3927 /* If the number of bits in the reference is the same as the bitsize of
3928 the outer type, then the outer type gives the signedness. Otherwise
3929 (in case of a small bitfield) the signedness is unchanged. */
3933 /* Compute the mask to access the bitfield. */
3942 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3950 }
3952 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3953 represents the sign bit of EXP's type. If EXP represents a sign
3954 or zero extension, also test VAL against the unextended type.
3955 The return value is the (sub)expression whose sign bit is VAL,
3956 or NULL_TREE otherwise. */
3958 static tree
3960 {
3964 tree t;
3966 /* Tree EXP must have an integral type. */
3971 /* Tree VAL must be an integer constant. */
3978 {
3985 }
3986 else
3987 {
3994 }
3996 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
3997 treat VAL as if it were unsigned. */
4002 /* Handle extension from a narrower type. */
4008 }
4010 /* Subroutine for fold_truthop: determine if an operand is simple enough
4011 to be evaluated unconditionally. */
4013 static int
4015 {
4016 /* Strip any conversions that don't change the machine mode. */
4025 /* Don't regard global variables as simple. They may be
4026 allocated in ways unknown to the compiler (shared memory,
4027 #pragma weak, etc). */
4030 /* Loading a static variable is unduly expensive, but global
4031 registers aren't expensive. */
4033 }
4034 \f
4035 /* The following functions are subroutines to fold_range_test and allow it to
4036 try to change a logical combination of comparisons into a range test.
4038 For example, both
4039 X == 2 || X == 3 || X == 4 || X == 5
4040 and
4041 X >= 2 && X <= 5
4042 are converted to
4043 (unsigned) (X - 2) <= 3
4045 We describe each set of comparisons as being either inside or outside
4046 a range, using a variable named like IN_P, and then describe the
4047 range with a lower and upper bound. If one of the bounds is omitted,
4048 it represents either the highest or lowest value of the type.
4050 In the comments below, we represent a range by two numbers in brackets
4051 preceded by a "+" to designate being inside that range, or a "-" to
4052 designate being outside that range, so the condition can be inverted by
4053 flipping the prefix. An omitted bound is represented by a "-". For
4054 example, "- [-, 10]" means being outside the range starting at the lowest
4055 possible value and ending at 10, in other words, being greater than 10.
4056 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4057 always false.
4059 We set up things so that the missing bounds are handled in a consistent
4060 manner so neither a missing bound nor "true" and "false" need to be
4061 handled using a special case. */
4063 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4064 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4065 and UPPER1_P are nonzero if the respective argument is an upper bound
4066 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4067 must be specified for a comparison. ARG1 will be converted to ARG0's
4068 type if both are specified. */
4070 static tree
4073 {
4074 tree tem;
4078 /* If neither arg represents infinity, do the normal operation.
4079 Else, if not a comparison, return infinity. Else handle the special
4080 comparison rules. Note that most of the cases below won't occur, but
4081 are handled for consistency. */
4084 {
4089 }
4094 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4095 for neither. In real maths, we cannot assume open ended ranges are
4096 the same. But, this is computer arithmetic, where numbers are finite.
4097 We can therefore make the transformation of any unbounded range with
4098 the value Z, Z being greater than any representable number. This permits
4099 us to treat unbounded ranges as equal. */
4103 {
4124 }
4127 }
4128 \f
4129 /* Given EXP, a logical expression, set the range it is testing into
4130 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4131 actually being tested. *PLOW and *PHIGH will be made of the same
4132 type as the returned expression. If EXP is not a comparison, we
4133 will most likely not be returning a useful value and range. Set
4134 *STRICT_OVERFLOW_P to true if the return value is only valid
4135 because signed overflow is undefined; otherwise, do not change
4136 *STRICT_OVERFLOW_P. */
4138 static tree
4141 {
4148 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4149 and see if we can refine the range. Some of the cases below may not
4150 happen, but it doesn't seem worth worrying about this. We "continue"
4151 the outer loop when we've changed something; otherwise we "break"
4152 the switch, which will "break" the while. */
4158 {
4163 {
4175 }
4178 {
4185 /* We can only do something if the range is testing for zero
4186 and if the second operand is an integer constant. Note that
4187 saying something is "in" the range we make is done by
4188 complementing IN_P since it will set in the initial case of
4189 being not equal to zero; "out" is leaving it alone. */
4196 {
4217 }
4219 /* If this is an unsigned comparison, we also know that EXP is
4220 greater than or equal to zero. We base the range tests we make
4221 on that fact, so we record it here so we can parse existing
4222 range tests. We test arg0_type since often the return type
4223 of, e.g. EQ_EXPR, is boolean. */
4225 {
4229 NULL_TREE))
4234 /* If the high bound is missing, but we have a nonzero low
4235 bound, reverse the range so it goes from zero to the low bound
4236 minus 1. */
4238 {
4243 }
4244 }
4250 /* (-x) IN [a,b] -> x in [-b, -a] */
4262 /* ~ X -> -X - 1 */
4271 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4272 move a constant to the other side. */
4277 /* If EXP is signed, any overflow in the computation is undefined,
4278 so we don't worry about it so long as our computations on
4279 the bounds don't overflow. For unsigned, overflow is defined
4280 and this is exactly the right thing. */
4292 /* Check for an unsigned range which has wrapped around the maximum
4293 value thus making n_high < n_low, and normalize it. */
4295 {
4301 /* If the range is of the form +/- [ x+1, x ], we won't
4302 be able to normalize it. But then, it represents the
4303 whole range or the empty set, so make it
4304 +/- [ -, - ]. */
4308 else
4310 }
4311 else
4335 /* If we're converting arg0 from an unsigned type, to exp,
4336 a signed type, we will be doing the comparison as unsigned.
4337 The tests above have already verified that LOW and HIGH
4338 are both positive.
4340 So we have to ensure that we will handle large unsigned
4341 values the same way that the current signed bounds treat
4342 negative values. */
4345 {
4346 tree high_positive;
4347 tree equiv_type;
4348 /* For fixed-point modes, we need to pass the saturating flag
4349 as the 2nd parameter. */
4354 else
4358 /* A range without an upper bound is, naturally, unbounded.
4359 Since convert would have cropped a very large value, use
4360 the max value for the destination type. */
4361 high_positive
4368 high_positive),
4371 /* If the low bound is specified, "and" the range with the
4372 range for which the original unsigned value will be
4373 positive. */
4375 {
4379 integer_zero_node),
4380 high_positive))
4384 }
4385 else
4386 {
4387 /* Otherwise, "or" the range with the range of the input
4388 that will be interpreted as negative. */
4392 integer_zero_node),
4393 high_positive))
4397 }
4398 }
4406 }
4409 }
4411 /* If EXP is a constant, we can evaluate whether this is true or false. */
4413 {
4420 }
4424 }
4425 \f
4426 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4427 type, TYPE, return an expression to test if EXP is in (or out of, depending
4428 on IN_P) the range. Return 0 if the test couldn't be created. */
4430 static tree
4432 {
4434 tree value;
4436 #ifdef HAVE_canonicalize_funcptr_for_compare
4437 /* Disable this optimization for function pointer expressions
4438 on targets that require function pointer canonicalization. */
4443 #endif
4446 {
4452 }
4470 {
4472 {
4476 }
4478 }
4480 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4482 {
4484 HOST_WIDE_INT hi;
4489 {
4492 }
4493 else
4494 {
4497 }
4500 {
4502 {
4505 }
4508 }
4509 }
4511 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4512 This requires wrap-around arithmetics for the type of the expression. */
4514 {
4516 /* There is no requirement that LOW be within the range of ETYPE
4517 if the latter is a subtype. It must, however, be within the base
4518 type of ETYPE. So be sure we do the subtraction in that type. */
4531 }
4533 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4536 {
4539 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4540 for the type in question, as we rely on this here. */
4550 else
4552 }
4562 {
4564 {
4570 }
4572 }
4580 }
4581 \f
4582 /* Return the predecessor of VAL in its type, handling the infinite case. */
4584 static tree
4586 {
4592 else
4594 }
4596 /* Return the successor of VAL in its type, handling the infinite case. */
4598 static tree
4600 {
4606 else
4608 }
4610 /* Given two ranges, see if we can merge them into one. Return 1 if we
4611 can, 0 if we can't. Set the output range into the specified parameters. */
4613 static int
4616 {
4620 tree tem;
4630 /* Make range 0 be the range that starts first, or ends last if they
4631 start at the same value. Swap them if it isn't. */
4634 || (lowequal
4637 {
4641 }
4643 /* Now flag two cases, whether the ranges are disjoint or whether the
4644 second range is totally subsumed in the first. Note that the tests
4645 below are simplified by the ones above. */
4651 /* We now have four cases, depending on whether we are including or
4652 excluding the two ranges. */
4654 {
4655 /* If they don't overlap, the result is false. If the second range
4656 is a subset it is the result. Otherwise, the range is from the start
4657 of the second to the end of the first. */
4662 else
4664 }
4667 {
4668 /* If they don't overlap, the result is the first range. If they are
4669 equal, the result is false. If the second range is a subset of the
4670 first, and the ranges begin at the same place, we go from just after
4671 the end of the second range to the end of the first. If the second
4672 range is not a subset of the first, or if it is a subset and both
4673 ranges end at the same place, the range starts at the start of the
4674 first range and ends just before the second range.
4675 Otherwise, we can't describe this as a single range. */
4681 {
4686 {
4687 /* We are in the weird situation where high0 > high1 but
4688 high1 has no successor. Punt. */
4690 }
4691 }
4693 {
4698 {
4699 /* low0 < low1 but low1 has no predecessor. Punt. */
4701 }
4702 }
4703 else
4705 }
4708 {
4709 /* If they don't overlap, the result is the second range. If the second
4710 is a subset of the first, the result is false. Otherwise,
4711 the range starts just after the first range and ends at the
4712 end of the second. */
4717 else
4718 {
4723 {
4724 /* high1 > high0 but high0 has no successor. Punt. */
4726 }
4727 }
4728 }
4730 else
4731 {
4732 /* The case where we are excluding both ranges. Here the complex case
4733 is if they don't overlap. In that case, the only time we have a
4734 range is if they are adjacent. If the second is a subset of the
4735 first, the result is the first. Otherwise, the range to exclude
4736 starts at the beginning of the first range and ends at the end of the
4737 second. */
4739 {
4744 else
4745 {
4746 /* Canonicalize - [min, x] into - [-, x]. */
4749 {
4754 /* FALLTHROUGH */
4767 }
4769 /* Canonicalize - [x, max] into - [x, -]. */
4772 {
4777 /* FALLTHROUGH */
4792 }
4794 /* The ranges might be also adjacent between the maximum and
4795 minimum values of the given type. For
4796 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4797 return + [x + 1, y - 1]. */
4799 {
4806 }
4807 else
4809 }
4810 }
4813 else
4815 }
4819 }
4820 \f
4822 /* Subroutine of fold, looking inside expressions of the form
4823 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4824 of the COND_EXPR. This function is being used also to optimize
4825 A op B ? C : A, by reversing the comparison first.
4827 Return a folded expression whose code is not a COND_EXPR
4828 anymore, or NULL_TREE if no folding opportunity is found. */
4830 static tree
4832 {
4837 tree tem;
4842 /* If we have A op 0 ? A : -A, consider applying the following
4843 transformations:
4845 A == 0? A : -A same as -A
4846 A != 0? A : -A same as A
4847 A >= 0? A : -A same as abs (A)
4848 A > 0? A : -A same as abs (A)
4849 A <= 0? A : -A same as -abs (A)
4850 A < 0? A : -A same as -abs (A)
4852 None of these transformations work for modes with signed
4853 zeros. If A is +/-0, the first two transformations will
4854 change the sign of the result (from +0 to -0, or vice
4855 versa). The last four will fix the sign of the result,
4856 even though the original expressions could be positive or
4857 negative, depending on the sign of A.
4859 Note that all these transformations are correct if A is
4860 NaN, since the two alternatives (A and -A) are also NaNs. */
4867 /* In the case that A is of the form X-Y, '-A' (arg2) may
4868 have already been folded to Y-X, check for that. */
4876 {
4888 /* Fall through. */
4910 }
4912 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4913 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4914 both transformations are correct when A is NaN: A != 0
4915 is then true, and A == 0 is false. */
4919 {
4924 }
4926 /* Try some transformations of A op B ? A : B.
4928 A == B? A : B same as B
4929 A != B? A : B same as A
4930 A >= B? A : B same as max (A, B)
4931 A > B? A : B same as max (B, A)
4932 A <= B? A : B same as min (A, B)
4933 A < B? A : B same as min (B, A)
4935 As above, these transformations don't work in the presence
4936 of signed zeros. For example, if A and B are zeros of
4937 opposite sign, the first two transformations will change
4938 the sign of the result. In the last four, the original
4939 expressions give different results for (A=+0, B=-0) and
4940 (A=-0, B=+0), but the transformed expressions do not.
4942 The first two transformations are correct if either A or B
4943 is a NaN. In the first transformation, the condition will
4944 be false, and B will indeed be chosen. In the case of the
4945 second transformation, the condition A != B will be true,
4946 and A will be chosen.
4948 The conversions to max() and min() are not correct if B is
4949 a number and A is not. The conditions in the original
4950 expressions will be false, so all four give B. The min()
4951 and max() versions would give a NaN instead. */
4954 /* Avoid these transformations if the COND_EXPR may be used
4955 as an lvalue in the C++ front-end. PR c++/19199. */
4956 && (in_gimple_form
4961 {
4966 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4968 {
4972 }
4975 {
4984 /* In C++ a ?: expression can be an lvalue, so put the
4985 operand which will be used if they are equal first
4986 so that we can convert this back to the
4987 corresponding COND_EXPR. */
4989 {
4996 }
5003 {
5010 }
5023 }
5024 }
5026 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5027 we might still be able to simplify this. For example,
5028 if C1 is one less or one more than C2, this might have started
5029 out as a MIN or MAX and been transformed by this function.
5030 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5036 {
5038 /* We can replace A with C1 in this case. */
5043 /* If C1 is C2 + 1, this is min(A, C2). */
5045 OEP_ONLY_CONST)
5049 OEP_ONLY_CONST))
5051 type,
5053 arg2));
5057 /* If C1 is C2 - 1, this is min(A, C2). */
5059 OEP_ONLY_CONST)
5063 OEP_ONLY_CONST))
5065 type,
5067 arg2));
5071 /* If C1 is C2 - 1, this is max(A, C2). */
5073 OEP_ONLY_CONST)
5077 OEP_ONLY_CONST))
5079 type,
5081 arg2));
5085 /* If C1 is C2 + 1, this is max(A, C2). */
5087 OEP_ONLY_CONST)
5091 OEP_ONLY_CONST))
5093 type,
5095 arg2));
5101 }
5104 }
5107 \f
5108 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5109 #define LOGICAL_OP_NON_SHORT_CIRCUIT (BRANCH_COST >= 2)
5110 #endif
5112 /* EXP is some logical combination of boolean tests. See if we can
5113 merge it into some range test. Return the new tree if so. */
5115 static tree
5117 {
5125 tree tem;
5129 /* If this is an OR operation, invert both sides; we will invert
5130 again at the end. */
5134 /* If both expressions are the same, if we can merge the ranges, and we
5135 can build the range test, return it or it inverted. If one of the
5136 ranges is always true or always false, consider it to be the same
5137 expression as the other. */
5145 {
5149 }
5151 /* On machines where the branch cost is expensive, if this is a
5152 short-circuited branch and the underlying object on both sides
5153 is the same, make a non-short-circuit operation. */
5159 {
5160 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5161 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5162 which cases we can't do this. */
5170 {
5179 {
5182 WARN_STRICT_OVERFLOW_COMPARISON);
5186 }
5187 }
5188 }
5191 }
5192 \f
5193 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5194 bit value. Arrange things so the extra bits will be set to zero if and
5195 only if C is signed-extended to its full width. If MASK is nonzero,
5196 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5198 static tree
5200 {
5203 tree temp;
5208 /* We work by getting just the sign bit into the low-order bit, then
5209 into the high-order bit, then sign-extend. We then XOR that value
5210 with C. */
5214 /* We must use a signed type in order to get an arithmetic right shift.
5215 However, we must also avoid introducing accidental overflows, so that
5216 a subsequent call to integer_zerop will work. Hence we must
5217 do the type conversion here. At this point, the constant is either
5218 zero or one, and the conversion to a signed type can never overflow.
5219 We could get an overflow if this conversion is done anywhere else. */
5228 /* If necessary, convert the type back to match the type of C. */
5233 }
5234 \f
5235 /* Find ways of folding logical expressions of LHS and RHS:
5236 Try to merge two comparisons to the same innermost item.
5237 Look for range tests like "ch >= '0' && ch <= '9'".
5238 Look for combinations of simple terms on machines with expensive branches
5239 and evaluate the RHS unconditionally.
5241 For example, if we have p->a == 2 && p->b == 4 and we can make an
5242 object large enough to span both A and B, we can do this with a comparison
5243 against the object ANDed with the a mask.
5245 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5246 operations to do this with one comparison.
5248 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5249 function and the one above.
5251 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5252 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5254 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5255 two operands.
5257 We return the simplified tree or 0 if no optimization is possible. */
5259 static tree
5261 {
5262 /* If this is the "or" of two comparisons, we can do something if
5263 the comparisons are NE_EXPR. If this is the "and", we can do something
5264 if the comparisons are EQ_EXPR. I.e.,
5265 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5267 WANTED_CODE is this operation code. For single bit fields, we can
5268 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5269 comparison for one-bit fields. */
5291 /* Start by getting the comparison codes. Fail if anything is volatile.
5292 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5293 it were surrounded with a NE_EXPR. */
5302 {
5306 }
5309 {
5313 }
5324 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5327 {
5328 tree result;
5331 {
5336 }
5339 {
5345 }
5346 }
5351 /* If the RHS can be evaluated unconditionally and its operands are
5352 simple, it wins to evaluate the RHS unconditionally on machines
5353 with expensive branches. In this case, this isn't a comparison
5354 that can be merged. Avoid doing this if the RHS is a floating-point
5355 comparison since those can trap. */
5361 {
5362 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5373 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5385 {
5389 }
5390 }
5392 /* See if the comparisons can be merged. Then get all the parameters for
5393 each side. */
5417 /* It must be true that the inner operation on the lhs of each
5418 comparison must be the same if we are to be able to do anything.
5419 Then see if we have constants. If not, the same must be true for
5420 the rhs's. */
5431 else
5434 /* If either comparison code is not correct for our logical operation,
5435 fail. However, we can convert a one-bit comparison against zero into
5436 the opposite comparison against that bit being set in the field. */
5440 {
5442 {
5443 /* Make the left operand unsigned, since we are only interested
5444 in the value of one bit. Otherwise we are doing the wrong
5445 thing below. */
5448 }
5449 else
5451 }
5453 /* This is analogous to the code for l_const above. */
5455 {
5457 {
5460 }
5461 else
5463 }
5465 /* See if we can find a mode that contains both fields being compared on
5466 the left. If we can't, fail. Otherwise, update all constants and masks
5467 to be relative to a field of that size. */
5472 volatilep);
5482 {
5485 }
5493 {
5501 {
5505 }
5506 }
5508 {
5516 {
5520 }
5521 }
5523 /* Handle the case of comparisons with constants. If there is something in
5524 common between the masks, those bits of the constants must be the same.
5525 If not, the condition is always false. Test for this to avoid generating
5526 incorrect code below. */
5531 {
5533 {
5536 }
5537 else
5538 {
5541 }
5542 }
5545 }
5546 \f
5547 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5548 constant. */
5550 static tree
5552 {
5555 tree comp_const;
5556 tree minmax_const;
5558 tree inner;
5569 /* If something does not permit us to optimize, return the original tree. */
5577 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5578 and GT_EXPR, doing the rest with recursive calls using logical
5579 simplifications. */
5581 {
5583 {
5589 }
5592 return
5594 optimize_minmax_comparison
5596 optimize_minmax_comparison
5601 /* MAX (X, 0) == 0 -> X <= 0 */
5605 /* MAX (X, 0) == 5 -> X == 5 */
5609 /* MAX (X, 0) == -1 -> false */
5613 /* MIN (X, 0) == 0 -> X >= 0 */
5617 /* MIN (X, 0) == 5 -> false */
5620 else
5621 /* MIN (X, 0) == -1 -> X == -1 */
5626 /* MAX (X, 0) > 0 -> X > 0
5627 MAX (X, 0) > 5 -> X > 5 */
5631 /* MAX (X, 0) > -1 -> true */
5635 /* MIN (X, 0) > 0 -> false
5636 MIN (X, 0) > 5 -> false */
5639 else
5640 /* MIN (X, 0) > -1 -> X > -1 */
5645 }
5646 }
5647 \f
5648 /* T is an integer expression that is being multiplied, divided, or taken a
5649 modulus (CODE says which and what kind of divide or modulus) by a
5650 constant C. See if we can eliminate that operation by folding it with
5651 other operations already in T. WIDE_TYPE, if non-null, is a type that
5652 should be used for the computation if wider than our type.
5654 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5655 (X * 2) + (Y * 4). We must, however, be assured that either the original
5656 expression would not overflow or that overflow is undefined for the type
5657 in the language in question.
5659 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5660 the machine has a multiply-accumulate insn or that this is part of an
5661 addressing calculation.
5663 If we return a non-null expression, it is an equivalent form of the
5664 original computation, but need not be in the original type.
5666 We set *STRICT_OVERFLOW_P to true if the return values depends on
5667 signed overflow being undefined. Otherwise we do not change
5668 *STRICT_OVERFLOW_P. */
5670 static tree
5673 {
5674 /* To avoid exponential search depth, refuse to allow recursion past
5675 three levels. Beyond that (1) it's highly unlikely that we'll find
5676 something interesting and (2) we've probably processed it before
5677 when we built the inner expression. */
5680 tree ret;
5685 depth++;
5687 depth--;
5690 }
5692 static tree
5695 {
5706 /* Don't deal with constants of zero here; they confuse the code below. */
5716 /* Note that we need not handle conditional operations here since fold
5717 already handles those cases. So just do arithmetic here. */
5719 {
5721 /* For a constant, we can always simplify if we are a multiply
5722 or (for divide and modulus) if it is a multiple of our constant. */
5730 /* If op0 is an expression ... */
5736 /* ... and is unsigned, and its type is smaller than ctype,
5737 then we cannot pass through as widening. */
5743 /* ... or this is a truncation (t is narrower than op0),
5744 then we cannot pass through this narrowing. */
5747 /* ... or signedness changes for division or modulus,
5748 then we cannot pass through this conversion. */
5752 /* ... or has undefined overflow while the converted to
5753 type has not, we cannot do the operation in the inner type
5754 as that would introduce undefined overflow. */
5759 /* Pass the constant down and see if we can make a simplification. If
5760 we can, replace this expression with the inner simplification for
5761 possible later conversion to our or some other type. */
5766 code == MULT_EXPR
5768 strict_overflow_p))))
5773 /* If widening the type changes it from signed to unsigned, then we
5774 must avoid building ABS_EXPR itself as unsigned. */
5776 {
5780 {
5783 }
5785 }
5786 /* If the constant is negative, we cannot simplify this. */
5789 /* FALLTHROUGH */
5797 /* If widening the type changes the signedness, then we can't perform
5798 this optimization as that changes the result. */
5802 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5808 {
5815 }
5819 /* If the second operand is constant, this is a multiplication
5820 or floor division, by a power of two, so we can treat it that
5821 way unless the multiplier or divisor overflows. Signed
5822 left-shift overflow is implementation-defined rather than
5823 undefined in C90, so do not convert signed left shift into
5824 multiplication. */
5827 /* const_binop may not detect overflow correctly,
5828 so check for it explicitly here. */
5833 size_one_node,
5843 /* See if we can eliminate the operation on both sides. If we can, we
5844 can return a new PLUS or MINUS. If we can't, the only remaining
5845 cases where we can do anything are if the second operand is a
5846 constant. */
5852 /* If not multiplication, we can only do this if both operands
5853 are divisible by c. */
5856 {
5861 }
5863 /* If this was a subtraction, negate OP1 and set it to be an addition.
5864 This simplifies the logic below. */
5871 /* If either OP1 or C are negative, this optimization is not safe for
5872 some of the division and remainder types while for others we need
5873 to change the code. */
5875 {
5883 }
5885 /* If it's a multiply or a division/modulus operation of a multiple
5886 of our constant, do the operation and verify it doesn't overflow. */
5889 {
5892 /* We allow the constant to overflow with wrapping semantics. */
5896 }
5897 else
5900 /* If we have an unsigned type is not a sizetype, we cannot widen
5901 the operation since it will change the result if the original
5902 computation overflowed. */
5908 /* If we were able to eliminate our operation from the first side,
5909 apply our operation to the second side and reform the PLUS. */
5913 /* The last case is if we are a multiply. In that case, we can
5914 apply the distributive law to commute the multiply and addition
5915 if the multiplication of the constants doesn't overflow. */
5921 op1);
5926 /* We have a special case here if we are doing something like
5927 (C * 8) % 4 since we know that's zero. */
5934 /* ... fall through ... */
5938 /* If we can extract our operation from the LHS, do so and return a
5939 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5940 do something only if the second operand is a constant. */
5954 /* If these are the same operation types, we can associate them
5955 assuming no overflow. */
5967 /* If these operations "cancel" each other, we have the main
5968 optimizations of this pass, which occur when either constant is a
5969 multiple of the other, in which case we replace this with either an
5970 operation or CODE or TCODE.
5972 If we have an unsigned type that is not a sizetype, we cannot do
5973 this since it will change the result if the original computation
5974 overflowed. */
5982 {
5984 {
5991 }
5993 {
6000 }
6001 }
6006 }
6009 }
6010 \f
6011 /* Return a node which has the indicated constant VALUE (either 0 or
6012 1), and is of the indicated TYPE. */
6014 tree
6016 {
6021 else
6023 }
6026 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6027 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6028 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6029 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6030 COND is the first argument to CODE; otherwise (as in the example
6031 given here), it is the second argument. TYPE is the type of the
6032 original expression. Return NULL_TREE if no simplification is
6033 possible. */
6035 static tree
6039 {
6046 /* This transformation is only worthwhile if we don't have to wrap
6047 arg in a SAVE_EXPR, and the operation can be simplified on at least
6048 one of the branches once its pushed inside the COND_EXPR. */
6053 {
6057 /* If this operand throws an expression, then it does not make
6058 sense to try to perform a logical or arithmetic operation
6059 involving it. */
6064 }
6065 else
6066 {
6071 }
6075 {
6079 else
6081 }
6083 {
6087 else
6089 }
6093 }
6095 \f
6096 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6098 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6099 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6100 ADDEND is the same as X.
6102 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6103 and finite. The problematic cases are when X is zero, and its mode
6104 has signed zeros. In the case of rounding towards -infinity,
6105 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6106 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6108 bool
6110 {
6114 /* Don't allow the fold with -fsignaling-nans. */
6118 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6122 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6127 /* The mode has signed zeros, and we have to honor their sign.
6128 In this situation, there is only one case we can return true for.
6129 X - 0 is the same as X unless rounding towards -infinity is
6130 supported. */
6132 }
6134 /* Subroutine of fold() that checks comparisons of built-in math
6135 functions against real constants.
6137 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6138 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6139 is the type of the result and ARG0 and ARG1 are the operands of the
6140 comparison. ARG1 must be a TREE_REAL_CST.
6142 The function returns the constant folded tree if a simplification
6143 can be made, and NULL_TREE otherwise. */
6145 static tree
6148 {
6149 REAL_VALUE_TYPE c;
6152 {
6158 {
6159 /* sqrt(x) < y is always false, if y is negative. */
6163 /* sqrt(x) > y is always true, if y is negative and we
6164 don't care about NaNs, i.e. negative values of x. */
6168 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6171 }
6173 {
6174 REAL_VALUE_TYPE c2;
6180 {
6181 /* sqrt(x) > y is x == +Inf, when y is very large. */
6186 /* sqrt(x) > y is always false, when y is very large
6187 and we don't care about infinities. */
6189 }
6191 /* sqrt(x) > c is the same as x > c*c. */
6194 }
6196 {
6197 REAL_VALUE_TYPE c2;
6203 {
6204 /* sqrt(x) < y is always true, when y is a very large
6205 value and we don't care about NaNs or Infinities. */
6209 /* sqrt(x) < y is x != +Inf when y is very large and we
6210 don't care about NaNs. */
6215 /* sqrt(x) < y is x >= 0 when y is very large and we
6216 don't care about Infinities. */
6221 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6230 dconst0)),
6233 c2)));
6234 }
6236 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6241 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6244 {
6249 dconst0)),
6252 c2)));
6253 }
6254 }
6255 }
6258 }
6260 /* Subroutine of fold() that optimizes comparisons against Infinities,
6261 either +Inf or -Inf.
6263 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6264 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6265 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6267 The function returns the constant folded tree if a simplification
6268 can be made, and NULL_TREE otherwise. */
6270 static tree
6272 {
6274 REAL_VALUE_TYPE max;
6275 tree temp;
6280 /* For negative infinity swap the sense of the comparison. */
6286 {
6288 /* x > +Inf is always false, if with ignore sNANs. */
6294 /* x <= +Inf is always true, if we don't case about NaNs. */
6298 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6301 {
6304 }
6309 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6315 /* x < +Inf is always equal to x <= DBL_MAX. */
6321 /* x != +Inf is always equal to !(x > DBL_MAX). */
6333 }
6336 }
6338 /* Subroutine of fold() that optimizes comparisons of a division by
6339 a nonzero integer constant against an integer constant, i.e.
6340 X/C1 op C2.
6342 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6343 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6344 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6346 The function returns the constant folded tree if a simplification
6347 can be made, and NULL_TREE otherwise. */
6349 static tree
6351 {
6356 HOST_WIDE_INT hpart;
6361 /* We have to do this the hard way to detect unsigned overflow.
6362 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6373 {
6378 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6386 }
6388 {
6392 {
6411 }
6412 }
6413 else
6414 {
6415 /* A negative divisor reverses the relational operators. */
6421 {
6440 }
6441 }
6444 {
6465 {
6468 }
6473 {
6476 }
6481 {
6484 }
6489 {
6492 }
6497 }
6500 }
6503 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6504 equality/inequality test, then return a simplified form of the test
6505 using a sign testing. Otherwise return NULL. TYPE is the desired
6506 result type. */
6508 static tree
6510 tree result_type)
6511 {
6512 /* If this is testing a single bit, we can optimize the test. */
6516 {
6517 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6518 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6522 /* This is only a win if casting to a signed type is cheap,
6523 i.e. when arg00's type is not a partial mode. */
6526 {
6531 }
6532 }
6535 }
6537 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6538 equality/inequality test, then return a simplified form of
6539 the test using shifts and logical operations. Otherwise return
6540 NULL. TYPE is the desired result type. */
6542 tree
6544 tree result_type)
6545 {
6546 /* If this is testing a single bit, we can optimize the test. */
6550 {
6559 /* First, see if we can fold the single bit test into a sign-bit
6560 test. */
6562 result_type);
6566 /* Otherwise we have (A & C) != 0 where C is a single bit,
6567 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6568 Similarly for (A & C) == 0. */
6570 /* If INNER is a right shift of a constant and it plus BITNUM does
6571 not overflow, adjust BITNUM and INNER. */
6578 {
6581 }
6583 /* If we are going to be able to omit the AND below, we must do our
6584 operations as unsigned. If we must use the AND, we have a choice.
6585 Normally unsigned is faster, but for some machines signed is. */
6586 #ifdef LOAD_EXTEND_OP
6589 #else
6591 #endif
6607 /* Put the AND last so it can combine with more things. */
6610 /* Make sure to return the proper type. */
6614 }
6616 }
6618 /* Check whether we are allowed to reorder operands arg0 and arg1,
6619 such that the evaluation of arg1 occurs before arg0. */
6621 static bool
6623 {
6630 }
6632 /* Test whether it is preferable two swap two operands, ARG0 and
6633 ARG1, for example because ARG0 is an integer constant and ARG1
6634 isn't. If REORDER is true, only recommend swapping if we can
6635 evaluate the operands in reverse order. */
6637 bool
6639 {
6675 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6676 for commutative and comparison operators. Ensuring a canonical
6677 form allows the optimizers to find additional redundancies without
6678 having to explicitly check for both orderings. */
6684 /* Put SSA_NAMEs last. */
6690 /* Put variables last. */
6697 }
6699 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6700 ARG0 is extended to a wider type. */
6702 static tree
6704 {
6706 tree arg1_unw;
6715 #ifdef HAVE_canonicalize_funcptr_for_compare
6716 /* Disable this optimization if we're casting a function pointer
6717 type on targets that require function pointer canonicalization. */
6722 #endif
6729 /* If possible, express the comparison in the shorter mode. */
6751 /* If we are comparing with the integer that does not fit into the range
6752 of the shorter type, the result is known. */
6763 {
6790 }
6793 }
6795 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6796 ARG0 just the signedness is changed. */
6798 static tree
6801 {
6802 tree arg0_inner;
6812 #ifdef HAVE_canonicalize_funcptr_for_compare
6813 /* Disable this optimization if we're casting a function pointer
6814 type on targets that require function pointer canonicalization. */
6819 #endif
6824 /* If the conversion is from an integral subtype to its basetype
6825 leave it alone. */
6844 else
6848 }
6850 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6851 step of the array. Reconstructs s and delta in the case of s * delta
6852 being an integer constant (and thus already folded).
6853 ADDR is the address. MULT is the multiplicative expression.
6854 If the function succeeds, the new address expression is returned. Otherwise
6855 NULL_TREE is returned. */
6857 static tree
6859 {
6863 tree itype;
6866 /* Strip the nops that might be added when converting op1 to sizetype. */
6869 /* Canonicalize op1 into a possibly non-constant delta
6870 and an INTEGER_CST s. */
6872 {
6879 {
6882 }
6884 {
6887 }
6888 else
6890 }
6892 {
6895 }
6896 else
6897 {
6898 /* Simulate we are delta * 1. */
6901 }
6904 {
6906 {
6907 /* Remember if this was a multi-dimensional array. */
6920 {
6923 }
6924 else
6925 {
6926 /* Try if delta is a multiple of step. */
6931 }
6933 /* Only fold here if we can verify we do not overflow one
6934 dimension of a multi-dimensional array. */
6936 {
6937 tree tmp;
6953 }
6956 }
6957 else
6962 }
6964 /* We found the suitable array reference. So copy everything up to it,
6965 and replace the index. */
6972 {
6976 }
6984 }
6987 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6988 means A >= Y && A != MAX, but in this case we know that
6989 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6991 static tree
6993 {
7000 else
7009 {
7012 }
7014 {
7017 }
7018 else
7025 {
7026 /* Convert the pointer types into integer before taking the difference. */
7030 }
7031 else
7038 }
7040 /* Fold a sum or difference of at least one multiplication.
7041 Returns the folded tree or NULL if no simplification could be made. */
7043 static tree
7045 {
7049 /* (A * C) +- (B * C) -> (A+-B) * C.
7050 (A * C) +- A -> A * (C+-1).
7051 We are most concerned about the case where C is a constant,
7052 but other combinations show up during loop reduction. Since
7053 it is not difficult, try all four possibilities. */
7056 {
7059 }
7061 {
7064 }
7065 else
7066 {
7067 /* We cannot generate constant 1 for fract. */
7072 }
7074 {
7077 }
7079 {
7082 }
7083 else
7084 {
7085 /* We cannot generate constant 1 for fract. */
7090 }
7102 /* No identical multiplicands; see if we can find a common
7103 power-of-two factor in non-power-of-two multiplies. This
7104 can help in multi-dimensional array access. */
7107 {
7110 tree maybe_same;
7114 /* Move min of absolute values to int11. */
7117 {
7122 }
7123 else
7127 {
7135 }
7136 }
7146 }
7148 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7149 specified by EXPR into the buffer PTR of length LEN bytes.
7150 Return the number of bytes placed in the buffer, or zero
7151 upon failure. */
7153 static int
7155 {
7166 {
7170 else
7175 {
7182 else
7184 }
7185 else
7188 }
7190 }
7193 /* Subroutine of native_encode_expr. Encode the REAL_CST
7194 specified by EXPR into the buffer PTR of length LEN bytes.
7195 Return the number of bytes placed in the buffer, or zero
7196 upon failure. */
7198 static int
7200 {
7206 /* There are always 32 bits in each long, no matter the size of
7207 the hosts long. We handle floating point representations with
7208 up to 192 bits. */
7219 {
7224 {
7231 else
7233 }
7234 else
7237 }
7239 }
7241 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7242 specified by EXPR into the buffer PTR of length LEN bytes.
7243 Return the number of bytes placed in the buffer, or zero
7244 upon failure. */
7246 static int
7248 {
7250 tree part;
7261 }
7264 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7265 specified by EXPR into the buffer PTR of length LEN bytes.
7266 Return the number of bytes placed in the buffer, or zero
7267 upon failure. */
7269 static int
7271 {
7281 {
7283 {
7286 }
7287 else
7291 {
7294 }
7295 else
7296 {
7300 }
7302 }
7304 }
7307 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7308 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7309 buffer PTR of length LEN bytes. Return the number of bytes
7310 placed in the buffer, or zero upon failure. */
7312 int
7314 {
7316 {
7331 }
7332 }
7335 /* Subroutine of native_interpret_expr. Interpret the contents of
7336 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7337 If the buffer cannot be interpreted, return NULL_TREE. */
7339 static tree
7341 {
7355 {
7358 {
7365 else
7367 }
7368 else
7374 else
7377 }
7380 }
7383 /* Subroutine of native_interpret_expr. Interpret the contents of
7384 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7385 If the buffer cannot be interpreted, return NULL_TREE. */
7387 static tree
7389 {
7394 /* There are always 32 bits in each long, no matter the size of
7395 the hosts long. We handle floating point representations with
7396 up to 192 bits. */
7397 REAL_VALUE_TYPE r;
7408 {
7411 {
7418 else
7420 }
7421 else
7426 }
7430 }
7433 /* Subroutine of native_interpret_expr. Interpret the contents of
7434 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7435 If the buffer cannot be interpreted, return NULL_TREE. */
7437 static tree
7439 {
7454 }
7457 /* Subroutine of native_interpret_expr. Interpret the contents of
7458 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7459 If the buffer cannot be interpreted, return NULL_TREE. */
7461 static tree
7463 {
7475 {
7480 }
7482 }
7485 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7486 the buffer PTR of length LEN as a constant of type TYPE. For
7487 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7488 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7489 return NULL_TREE. */
7491 tree
7493 {
7495 {
7512 }
7513 }
7516 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7517 TYPE at compile-time. If we're unable to perform the conversion
7518 return NULL_TREE. */
7520 static tree
7522 {
7523 /* We support up to 512-bit values (for V8DFmode). */
7527 /* Check that the host and target are sane. */
7536 }
7538 /* Build an expression for the address of T. Folds away INDIRECT_REF
7539 to avoid confusing the gimplify process. When IN_FOLD is true
7540 avoid modifications of T. */
7542 static tree
7544 {
7545 /* The size of the object is not relevant when talking about its address. */
7549 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7552 {
7557 }
7559 {
7569 }
7570 else
7574 }
7576 /* Build an expression for the address of T with type PTRTYPE. This
7577 function modifies the input parameter 'T' by sometimes setting the
7578 TREE_ADDRESSABLE flag. */
7580 tree
7582 {
7584 }
7586 /* Build an expression for the address of T. This function modifies
7587 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7588 flag. When called from fold functions, use fold_addr_expr instead. */
7590 tree
7592 {
7596 }
7598 /* Same as build_fold_addr_expr, builds an expression for the address
7599 of T, but avoids touching the input node 't'. Fold functions
7600 should use this version. */
7602 static tree
7604 {
7608 }
7610 /* Fold a unary expression of code CODE and type TYPE with operand
7611 OP0. Return the folded expression if folding is successful.
7612 Otherwise, return NULL_TREE. */
7614 tree
7616 {
7617 tree tem;
7618 tree arg0;
7626 {
7629 {
7630 /* Don't use STRIP_NOPS, because signedness of argument type
7631 matters. */
7633 }
7634 else
7635 {
7636 /* Strip any conversions that don't change the mode. This
7637 is safe for every expression, except for a comparison
7638 expression because its signedness is derived from its
7639 operands.
7641 Note that this is done as an internal manipulation within
7642 the constant folder, in order to find the simplest
7643 representation of the arguments so that their form can be
7644 studied. In any cases, the appropriate type conversions
7645 should be put back in the tree that will get out of the
7646 constant folder. */
7648 }
7649 }
7652 {
7657 {
7667 /* If this was a conversion, and all we did was to move into
7668 inside the COND_EXPR, bring it back out. But leave it if
7669 it is a conversion from integer to integer and the
7670 result precision is no wider than a word since such a
7671 conversion is cheap and may be optimized away by combine,
7672 while it couldn't if it were outside the COND_EXPR. Then return
7673 so we don't get into an infinite recursion loop taking the
7674 conversion out and then back in. */
7686 && (INTEGRAL_TYPE_P
7698 }
7700 {
7702 {
7706 }
7710 integer_one_node),
7712 integer_zero_node));
7713 }
7714 }
7717 {
7719 /* Re-association barriers around constants and other re-association
7720 barriers can be removed. */
7726 CASE_CONVERT:
7732 /* If we have (type) (a CMP b) and type is an integral type, return
7733 new expression involving the new type. */
7738 /* Handle cases of two conversions in a row. */
7740 {
7762 /* In addition to the cases of two conversions in a row
7763 handled below, if we are converting something to its own
7764 type via an object of identical or wider precision, neither
7765 conversion is needed. */
7772 /* Likewise, if the intermediate and final types are either both
7773 float or both integer, we don't need the middle conversion if
7774 it is wider than the final type and doesn't change the signedness
7775 (for integers). Avoid this if the final type is a pointer
7776 since then we sometimes need the inner conversion. Likewise if
7777 the outer has a precision not equal to the size of its mode. */
7786 && ! final_ptr
7790 /* If we have a sign-extension of a zero-extended value, we can
7791 replace that by a single zero-extension. */
7797 /* Two conversions in a row are not needed unless:
7798 - some conversion is floating-point (overstrict for now), or
7799 - some conversion is a vector (overstrict for now), or
7800 - the intermediate type is narrower than both initial and
7801 final, or
7802 - the intermediate type and innermost type differ in signedness,
7803 and the outermost type is wider than the intermediate, or
7804 - the initial type is a pointer type and the precisions of the
7805 intermediate and final types differ, or
7806 - the final type is a pointer type and the precisions of the
7807 initial and intermediate types differ. */
7821 }
7823 /* Handle (T *)&A.B.C for A being of type T and B and C
7824 living at offset zero. This occurs frequently in
7825 C++ upcasting and then accessing the base. */
7829 {
7831 tree offset;
7837 /* If the reference was to a (constant) zero offset, we can use
7838 the address of the base if it has the same base type
7839 as the result type. */
7844 }
7849 /* Detect assigning a bitfield. */
7851 && DECL_BIT_FIELD
7853 {
7854 /* Don't leave an assignment inside a conversion
7855 unless assigning a bitfield. */
7857 /* First do the assignment, then return converted constant. */
7862 }
7864 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7865 constants (if x has signed type, the sign bit cannot be set
7866 in c). This folds extension into the BIT_AND_EXPR. */
7871 {
7881 <= HOST_BITS_PER_WIDE_INT
7883 {
7890 #ifdef LOAD_EXTEND_OP
7892 && !flag_syntax_only
7895 {
7899 }
7900 #endif
7901 }
7903 {
7909 }
7910 }
7912 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7913 when one of the new casts will fold away. Conservatively we assume
7914 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7920 {
7926 }
7928 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7929 of the same precision, and X is an integer type not narrower than
7930 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7936 {
7941 }
7943 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7944 type of X and Y (integer types only). */
7949 {
7950 /* Be careful not to introduce new overflows. */
7951 tree mult_type;
7954 else
7961 }
7976 /* For integral conversions with the same precision or pointer
7977 conversions use a NOP_EXPR instead. */
7983 /* Do not muck with VIEW_CONVERT_EXPRs that convert from
7984 a sub-type to its base type as generated by the Ada FE. */
7989 /* Strip inner integral conversions that do not change the precision. */
8012 /* Convert fabs((double)float) into (double)fabsf(float). */
8015 {
8020 targ0));
8021 }
8022 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8028 /* Strip sign ops from argument. */
8030 {
8034 }
8041 {
8046 }
8048 {
8053 }
8063 /* Convert ~ (-A) to A - 1. */
8068 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8076 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8089 /* Perform BIT_NOT_EXPR on each element individually. */
8091 {
8096 {
8098 {
8104 }
8105 else
8108 }
8111 }
8116 /* The argument to invert_truthvalue must have Boolean type. */
8120 /* Note that the operand of this must be an int
8121 and its values must be 0 or 1.
8122 ("true" is a fixed value perhaps depending on the language,
8123 but we don't handle values other than 1 correctly yet.) */
8138 {
8146 }
8148 {
8152 }
8154 {
8158 {
8167 }
8168 }
8180 {
8188 }
8190 {
8194 }
8196 {
8200 {
8209 }
8210 }
8216 }
8218 /* Fold a binary expression of code CODE and type TYPE with operands
8219 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8220 Return the folded expression if folding is successful. Otherwise,
8221 return NULL_TREE. */
8223 static tree
8225 {
8232 else
8235 /* MIN (MAX (a, b), b) == b. */
8240 /* MIN (MAX (b, a), b) == b. */
8246 /* MIN (a, MAX (a, b)) == a. */
8252 /* MIN (a, MAX (b, a)) == a. */
8259 }
8261 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8262 by changing CODE to reduce the magnitude of constants involved in
8263 ARG0 of the comparison.
8264 Returns a canonicalized comparison tree if a simplification was
8265 possible, otherwise returns NULL_TREE.
8266 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8267 valid if signed overflow is undefined. */
8269 static tree
8273 {
8279 /* Match A +- CST code arg1 and CST code arg1. */
8286 /* Identify the constant in arg0 and its sign. */
8289 else
8293 /* Overflowed constants and zero will cause problems. */
8298 /* See if we can reduce the magnitude of the constant in
8299 arg0 by changing the comparison code. */
8301 {
8302 /* CST <= arg1 -> CST-1 < arg1. */
8305 /* -CST < arg1 -> -CST-1 <= arg1. */
8308 /* CST > arg1 -> CST-1 >= arg1. */
8311 /* -CST >= arg1 -> -CST-1 > arg1. */
8314 else
8316 /* arg1 code' CST' might be more canonical. */
8318 }
8319 else
8320 {
8321 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8325 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8329 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8333 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8337 else
8340 }
8342 /* Now build the constant reduced in magnitude. */
8348 /* If swapping might yield to a more canonical form, do so. */
8351 else
8353 }
8355 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8356 overflow further. Try to decrease the magnitude of constants involved
8357 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8358 and put sole constants at the second argument position.
8359 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8361 static tree
8364 {
8365 tree t;
8370 /* In principle pointers also have undefined overflow behavior,
8371 but that causes problems elsewhere. */
8376 /* Try canonicalization by simplifying arg0. */
8381 {
8385 }
8387 /* Try canonicalization by simplifying arg1 using the swapped
8388 comparison. */
8396 }
8398 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8399 space. This is used to avoid issuing overflow warnings for
8400 expressions like &p->x which can not wrap. */
8402 static bool
8404 {
8415 {
8418 }
8421 else
8422 {
8425 }
8440 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8441 array. */
8443 {
8444 HOST_WIDE_INT base_size;
8449 }
8452 }
8454 /* Subroutine of fold_binary. This routine performs all of the
8455 transformations that are common to the equality/inequality
8456 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8457 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8458 fold_binary should call fold_binary. Fold a comparison with
8459 tree code CODE and type TYPE with operands OP0 and OP1. Return
8460 the folded comparison or NULL_TREE. */
8462 static tree
8464 {
8477 /* If one arg is a real or integer constant, put it last. */
8481 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8488 {
8492 tree lhs;
8499 /* If the constant operation overflowed this can be
8500 simplified as a comparison against INT_MAX/INT_MIN. */
8503 {
8507 /* Get the sign of the constant on the lhs if the
8508 operation were VARIABLE + CONST1. */
8512 /* The sign of the constant determines if we overflowed
8513 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8514 Canonicalize to the INT_MIN overflow by swapping the comparison
8515 if necessary. */
8519 /* We now can look at the canonicalized case
8520 VARIABLE + 1 CODE2 INT_MIN
8521 and decide on the result. */
8530 }
8535 {
8537 "when changing X +- C1 cmp C2 to "
8539 WARN_STRICT_OVERFLOW_COMPARISON);
8541 }
8542 }
8544 /* For comparisons of pointers we can decompose it to a compile time
8545 comparison of the base objects and the offsets into the object.
8546 This requires at least one operand being an ADDR_EXPR or a
8547 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8553 {
8560 /* Get base and offset for the access. Strip ADDR_EXPR for
8561 get_inner_reference, but put it back by stripping INDIRECT_REF
8562 off the base object if possible. indirect_baseN will be true
8563 if baseN is not an address but refers to the object itself. */
8566 {
8572 else
8574 }
8576 {
8579 }
8583 {
8589 else
8591 }
8593 {
8596 }
8598 /* If we have equivalent bases we might be able to simplify. */
8601 {
8602 /* We can fold this expression to a constant if the non-constant
8603 offset parts are equal. */
8611 {
8618 "occur when comparing P +- C1 with "
8620 WARN_STRICT_OVERFLOW_CONDITIONAL);
8623 {
8637 }
8638 }
8639 /* We can simplify the comparison to a comparison of the variable
8640 offset parts if the constant offset parts are equal.
8641 Be careful to use signed size type here because otherwise we
8642 mess with array offsets in the wrong way. This is possible
8643 because pointer arithmetic is restricted to retain within an
8644 object and overflow on pointer differences is undefined as of
8645 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8649 {
8650 tree signed_size_type_node;
8653 /* By converting to signed size type we cover middle-end pointer
8654 arithmetic which operates on unsigned pointer types of size
8655 type size and ARRAY_REF offsets which are properly sign or
8656 zero extended from their type in case it is narrower than
8657 size type. */
8660 else
8664 else
8672 "occur when comparing P +- C1 with "
8674 WARN_STRICT_OVERFLOW_COMPARISON);
8677 }
8678 }
8679 /* For non-equal bases we can simplify if they are addresses
8680 of local binding decls or constants. */
8682 /* We know that !operand_equal_p (base0, base1, 0)
8683 because the if condition was false. But make
8684 sure two decls are not the same. */
8698 {
8703 }
8704 /* For equal offsets we can simplify to a comparison of the
8705 base addresses. */
8707 && (indirect_base0
8709 && (indirect_base1
8714 {
8720 }
8721 }
8723 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8724 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8725 the resulting offset is smaller in absolute value than the
8726 original one. */
8734 {
8739 tree cst;
8741 "occur when combining constants around "
8744 /* Put the constant on the side where it doesn't overflow and is
8745 of lower absolute value than before. */
8751 {
8754 variable1,
8757 }
8764 {
8769 variable2);
8770 }
8771 }
8773 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8774 signed arithmetic case. That form is created by the compiler
8775 often enough for folding it to be of value. One example is in
8776 computing loop trip counts after Operator Strength Reduction. */
8782 {
8791 "eliminating multiplication in comparison "
8793 WARN_STRICT_OVERFLOW_COMPARISON);
8795 /* If const1 is negative we swap the sense of the comparison. */
8800 }
8807 {
8815 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8820 /* (-a) CMP (-b) -> b CMP a */
8827 {
8828 REAL_VALUE_TYPE cst;
8831 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8838 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8839 /* a CMP (-0) -> a CMP 0 */
8844 /* x != NaN is always true, other ops are always false. */
8847 {
8850 }
8852 /* Fold comparisons against infinity. */
8854 {
8858 }
8859 }
8861 /* If this is a comparison of a real constant with a PLUS_EXPR
8862 or a MINUS_EXPR of a real constant, we can convert it into a
8863 comparison with a revised real constant as long as no overflow
8864 occurs when unsafe_math_optimizations are enabled. */
8876 /* Likewise, we can simplify a comparison of a real constant with
8877 a MINUS_EXPR whose first operand is also a real constant, i.e.
8878 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
8879 floating-point types only if -fassociative-math is set. */
8890 /* Fold comparisons against built-in math functions. */
8892 && flag_unsafe_math_optimizations
8894 {
8898 {
8902 }
8903 }
8904 }
8908 {
8909 /* If we are widening one operand of an integer comparison,
8910 see if the other operand is similarly being widened. Perhaps we
8911 can do the comparison in the narrower type. */
8916 /* Or if we are changing signedness. */
8920 }
8922 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8923 constant, we can simplify it. */
8928 {
8932 }
8934 /* Simplify comparison of something with itself. (For IEEE
8935 floating-point, we can only do some of these simplifications.) */
8937 {
8939 {
8954 /* For NE, we can only do this simplification if integer
8955 or we don't honor IEEE floating point NaNs. */
8959 /* ... fall through ... */
8965 }
8966 }
8968 /* If we are comparing an expression that just has comparisons
8969 of two integer values, arithmetic expressions of those comparisons,
8970 and constants, we can simplify it. There are only three cases
8971 to check: the two values can either be equal, the first can be
8972 greater, or the second can be greater. Fold the expression for
8973 those three values. Since each value must be 0 or 1, we have
8974 eight possibilities, each of which corresponds to the constant 0
8975 or 1 or one of the six possible comparisons.
8977 This handles common cases like (a > b) == 0 but also handles
8978 expressions like ((x > y) - (y > x)) > 0, which supposedly
8979 occur in macroized code. */
8982 {
8987 /* Don't handle degenerate cases here; they should already
8988 have been handled anyway. */
8997 {
9001 /* We can't just pass T to eval_subst in case cval1 or cval2
9002 was the same as ARG1. */
9004 tree high_result
9008 arg1);
9009 tree equal_result
9013 arg1);
9014 tree low_result
9018 arg1);
9020 /* All three of these results should be 0 or 1. Confirm they are.
9021 Then use those values to select the proper code to use. */
9026 {
9027 /* Make a 3-bit mask with the high-order bit being the
9028 value for `>', the next for '=', and the low for '<'. */
9032 {
9034 /* Always false. */
9055 /* Always true. */
9057 }
9062 }
9063 }
9064 }
9066 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9067 into a single range test. */
9075 {
9079 }
9081 /* Fold ~X op ~Y as Y op X. */
9084 {
9089 }
9091 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9094 {
9100 }
9103 }
9106 /* Subroutine of fold_binary. Optimize complex multiplications of the
9107 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9108 argument EXPR represents the expression "z" of type TYPE. */
9110 static tree
9112 {
9117 {
9120 }
9122 {
9125 }
9126 else
9127 {
9131 }
9140 }
9143 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9144 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9145 guarantees that P and N have the same least significant log2(M) bits.
9146 N is not otherwise constrained. In particular, N is not normalized to
9147 0 <= N < M as is common. In general, the precise value of P is unknown.
9148 M is chosen as large as possible such that constant N can be determined.
9150 Returns M and sets *RESIDUE to N. */
9152 static unsigned HOST_WIDE_INT
9154 {
9161 {
9164 {
9166 tree offset;
9174 {
9177 else
9178 /* We don't handle more complicated offset expressions. */
9180 }
9181 }
9185 }
9187 {
9200 {
9203 }
9205 {
9208 {
9211 /* Compute the greatest power-of-2 divisor of op1. */
9215 /* If align is non-zero and less than *modulus, replace
9216 *modulus with align., If align is 0, then either op1 is 0
9217 or the greatest power-of-2 divisor of op1 doesn't fit in an
9218 unsigned HOST_WIDE_INT. In either case, no additional
9219 constraint is imposed. */
9224 }
9225 }
9226 }
9228 /* If we get here, we were unable to determine anything useful about the
9229 expression. */
9231 }
9234 /* Fold a binary expression of code CODE and type TYPE with operands
9235 OP0 and OP1. Return the folded expression if folding is
9236 successful. Otherwise, return NULL_TREE. */
9238 tree
9240 {
9255 /* Strip any conversions that don't change the mode. This is
9256 safe for every expression, except for a comparison expression
9257 because its signedness is derived from its operands. So, in
9258 the latter case, only strip conversions that don't change the
9259 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9260 preserved.
9262 Note that this is done as an internal manipulation within the
9263 constant folder, in order to find the simplest representation
9264 of the arguments so that their form can be studied. In any
9265 cases, the appropriate type conversions should be put back in
9266 the tree that will get out of the constant folder. */
9269 {
9272 }
9273 else
9274 {
9277 }
9279 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9280 constant but we can't do arithmetic on them. */
9287 {
9289 {
9290 /* Make sure type and arg0 have the same saturating flag. */
9294 }
9297 else
9301 {
9305 }
9306 }
9308 /* If this is a commutative operation, and ARG0 is a constant, move it
9309 to ARG1 to reduce the number of tests below. */
9314 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9316 First check for cases where an arithmetic operation is applied to a
9317 compound, conditional, or comparison operation. Push the arithmetic
9318 operation inside the compound or conditional to see if any folding
9319 can then be done. Convert comparison to conditional for this purpose.
9320 The also optimizes non-constant cases that used to be done in
9321 expand_expr.
9323 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9324 one of the operands is a comparison and the other is a comparison, a
9325 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9326 code below would make the expression more complex. Change it to a
9327 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9328 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9340 {
9344 boolean_type_node,
9352 }
9356 {
9362 op1));
9371 {
9377 }
9380 {
9386 }
9387 }
9390 {
9392 /* 0 +p index -> (type)index */
9396 /* PTR +p 0 -> PTR */
9400 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9407 /* index +p PTR -> PTR +p index */
9414 /* (PTR +p B) +p A -> PTR +p (B + A) */
9416 {
9417 tree inner;
9425 }
9427 /* PTR_CST +p CST -> CST1 */
9431 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9432 of the array. Loop optimizer sometimes produce this type of
9433 expressions. */
9435 {
9439 }
9444 /* PTR + INT -> (INT)(PTR p+ INT) */
9449 arg0,
9451 /* INT + PTR -> (INT)(PTR p+ INT) */
9456 arg1,
9458 /* A + (-B) -> A - B */
9463 /* (-A) + B -> B - A */
9471 {
9472 /* Convert ~A + 1 to -A. */
9477 /* ~X + X is -1. */
9480 {
9485 {
9488 }
9489 }
9491 /* X + ~X is -1. */
9494 {
9499 {
9502 }
9503 }
9505 /* X + (X / CST) * -CST is X % CST. */
9510 {
9518 }
9519 }
9521 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9522 same or one. Make sure type is not saturating.
9523 fold_plusminus_mult_expr will re-associate. */
9528 {
9532 }
9535 {
9539 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9540 with a constant, and the two constants have no bits in common,
9541 we should treat this as a BIT_IOR_EXPR since this may produce more
9542 simplifications. */
9550 {
9553 }
9555 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9556 (plus (plus (mult) (mult)) (foo)) so that we can
9557 take advantage of the factoring cases below. */
9564 {
9570 else
9592 parg1)));
9593 }
9594 }
9595 else
9596 {
9597 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9601 /* Likewise if the operands are reversed. */
9605 /* Convert X + -C into X - C. */
9608 {
9614 }
9616 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9617 to __complex__ ( x, y ). This is not the same for SNaNs or
9618 if signed zeros are involved. */
9622 {
9629 {
9633 {
9639 }
9641 {
9647 }
9648 }
9649 }
9657 /* Convert x+x into x*2.0. */
9663 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9664 We associate floats only if the user has specified
9665 -fassociative-math. */
9669 {
9674 {
9675 tree tree0;
9678 }
9679 }
9680 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9681 We associate floats only if the user has specified
9682 -fassociative-math. */
9686 {
9691 {
9692 tree tree0;
9695 }
9696 }
9697 }
9699 bit_rotate:
9700 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9701 is a rotate of A by C1 bits. */
9702 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9703 is a rotate of A by B bits. */
9704 {
9706 tree rtype;
9715 /* Only create rotates in complete modes. Other cases are not
9716 expanded properly. */
9718 {
9737 {
9745 TYPE_PRECISION
9750 ? LROTATE_EXPR
9753 }
9755 {
9763 TYPE_PRECISION
9768 ? LROTATE_EXPR
9771 }
9772 }
9773 }
9775 associate:
9776 /* In most languages, can't associate operations on floats through
9777 parentheses. Rather than remember where the parentheses were, we
9778 don't associate floats at all, unless the user has specified
9779 -fassociative-math.
9780 And, we need to make sure type is not saturating. */
9784 {
9789 /* Split both trees into variables, constants, and literals. Then
9790 associate each group together, the constants with literals,
9791 then the result with variables. This increases the chances of
9792 literals being recombined later and of generating relocatable
9793 expressions for the sum of a constant and literal. */
9798 /* With undefined overflow we can only associate constants
9799 with one variable. */
9803 {
9811 /* The only case we can still associate with two variables
9812 is if they are the same, modulo negation. */
9815 }
9817 /* Only do something if we found more than two objects. Otherwise,
9818 nothing has changed and we risk infinite recursion. */
9824 {
9825 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9834 /* Preserve the MINUS_EXPR if the negative part of the literal is
9835 greater than the positive part. Otherwise, the multiplicative
9836 folding code (i.e extract_muldiv) may be fooled in case
9837 unsigned constants are subtracted, like in the following
9838 example: ((X*2 + 4) - 8U)/2. */
9840 {
9844 {
9848 }
9849 else
9850 {
9854 }
9855 }
9857 {
9862 else
9863 {
9869 }
9870 }
9875 }
9876 }
9881 /* Pointer simplifications for subtraction, simple reassociations. */
9883 {
9884 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
9887 {
9895 }
9896 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
9898 {
9904 }
9905 }
9906 /* A - (-B) -> A + B */
9910 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9919 /* Convert -A - 1 to ~A. */
9927 /* Convert -1 - A to ~A. */
9933 /* X - (X / CST) * CST is X % CST. */
9946 {
9952 /* Fold A - (A & B) into ~B & A. */
9955 {
9957 {
9962 }
9964 {
9969 }
9970 }
9972 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
9973 any power of 2 minus 1. */
9978 {
9984 {
9988 }
9989 }
9990 }
9992 /* See if ARG1 is zero and X - ARG1 reduces to X. */
9996 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
9997 ARG0 is zero and X + ARG0 reduces to X, since that would mean
9998 (-ARG1 + ARG0) reduces to -ARG1. */
10002 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10003 __complex__ ( x, -y ). This is not the same for SNaNs or if
10004 signed zeros are involved. */
10008 {
10015 {
10019 {
10021 arg1r ? arg1r
10026 }
10028 {
10032 arg1i ? arg1i
10035 }
10036 }
10037 }
10039 /* Fold &x - &x. This can happen from &x.foo - &x.
10040 This is unsafe for certain floats even in non-IEEE formats.
10041 In IEEE, it is unsafe because it does wrong for NaNs.
10042 Also note that operand_equal_p is always false if an operand
10043 is volatile. */
10049 /* A - B -> A + (-B) if B is easily negatable. */
10052 /* Avoid this transformation if B is a positive REAL_CST. */
10060 /* Try folding difference of addresses. */
10061 {
10062 HOST_WIDE_INT diff;
10068 }
10070 /* Fold &a[i] - &a[j] to i-j. */
10075 {
10080 {
10088 }
10089 }
10097 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10098 same or one. Make sure type is not saturating.
10099 fold_plusminus_mult_expr will re-associate. */
10104 {
10108 }
10113 /* (-A) * (-B) -> A * B */
10124 {
10129 /* Transform x * -1 into -x. Make sure to do the negation
10130 on the original operand with conversions not stripped
10131 because we can only strip non-sign-changing conversions. */
10134 /* Transform x * -C into -x * C if x is easily negatable. */
10143 /* (a * (1 << b)) is (a << b) */
10153 /* (A + A) * C -> A * 2 * C */
10168 {
10171 "occur when simplifying "
10173 WARN_STRICT_OVERFLOW_MISC);
10175 }
10177 /* Optimize z * conj(z) for integer complex numbers. */
10184 }
10185 else
10186 {
10187 /* Maybe fold x * 0 to 0. The expressions aren't the same
10188 when x is NaN, since x * 0 is also NaN. Nor are they the
10189 same in modes with signed zeros, since multiplying a
10190 negative value by 0 gives -0, not +0. */
10195 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10200 /* Transform x * -1.0 into -x. */
10205 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10206 the result for floating point types due to rounding so it is applied
10207 only if -fassociative-math was specify. */
10212 {
10218 }
10220 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10222 {
10225 {
10228 }
10229 }
10231 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10232 This is not the same for NaNs or if signed zeros are
10233 involved. */
10239 {
10251 }
10253 /* Optimize z * conj(z) for floating point complex numbers.
10254 Guarded by flag_unsafe_math_optimizations as non-finite
10255 imaginary components don't produce scalar results. */
10266 {
10270 /* Optimizations of root(...)*root(...). */
10272 {
10277 /* Optimize sqrt(x)*sqrt(x) as x. */
10283 /* Optimize root(x)*root(y) as root(x*y). */
10287 }
10289 /* Optimize expN(x)*expN(y) as expN(x+y). */
10291 {
10297 }
10299 /* Optimizations of pow(...)*pow(...). */
10303 {
10309 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10311 {
10315 }
10317 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10319 {
10323 }
10324 }
10326 /* Optimize tan(x)*cos(x) as sin(x). */
10335 {
10340 }
10342 /* Optimize x*pow(x,c) as pow(x,c+1). */
10346 {
10352 {
10354 REAL_VALUE_TYPE c;
10355 tree arg;
10361 }
10362 }
10364 /* Optimize pow(x,c)*x as pow(x,c+1). */
10368 {
10374 {
10376 REAL_VALUE_TYPE c;
10377 tree arg;
10383 }
10384 }
10386 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10389 {
10393 {
10396 }
10397 }
10398 }
10399 }
10403 bit_ior:
10411 /* ~X | X is -1. */
10414 {
10418 }
10420 /* X | ~X is -1. */
10423 {
10427 }
10429 /* Canonicalize (X & C1) | C2. */
10433 {
10441 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10446 {
10450 }
10451 else
10452 {
10456 }
10458 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10463 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10464 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10465 mode which allows further optimizations. */
10475 {
10476 unsigned HOST_WIDE_INT mask
10480 {
10484 }
10485 }
10492 arg1);
10493 }
10495 /* (X & Y) | Y is (X, Y). */
10499 /* (X & Y) | X is (Y, X). */
10504 /* X | (X & Y) is (Y, X). */
10509 /* X | (Y & X) is (Y, X). */
10519 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10521 This results in more efficient code for machines without a NAND
10522 instruction. Combine will canonicalize to the first form
10523 which will allow use of NAND instructions provided by the
10524 backend if they exist. */
10527 {
10534 }
10536 /* See if this can be simplified into a rotate first. If that
10537 is unsuccessful continue in the association code. */
10548 /* ~X ^ X is -1. */
10551 {
10555 }
10557 /* X ^ ~X is -1. */
10560 {
10564 }
10566 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10567 with a constant, and the two constants have no bits in common,
10568 we should treat this as a BIT_IOR_EXPR since this may produce more
10569 simplifications. */
10577 {
10580 }
10582 /* (X | Y) ^ X -> Y & ~ X*/
10585 {
10588 arg1);
10592 }
10594 /* (Y | X) ^ X -> Y & ~ X*/
10597 {
10600 arg1);
10604 }
10606 /* X ^ (X | Y) -> Y & ~ X*/
10609 {
10612 arg0);
10616 }
10618 /* X ^ (Y | X) -> Y & ~ X*/
10621 {
10624 arg0);
10628 }
10630 /* Convert ~X ^ ~Y to X ^ Y. */
10637 /* Convert ~X ^ C to X ^ ~C. */
10644 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10651 /* Fold (X & Y) ^ Y as ~X & Y. */
10654 {
10659 }
10660 /* Fold (X & Y) ^ X as ~Y & X. */
10664 {
10669 }
10670 /* Fold X ^ (X & Y) as X & ~Y. */
10673 {
10678 }
10679 /* Fold X ^ (Y & X) as ~Y & X. */
10683 {
10688 }
10690 /* See if this can be simplified into a rotate first. If that
10691 is unsuccessful continue in the association code. */
10702 /* ~X & X is always zero. */
10707 /* X & ~X is always zero. */
10712 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10716 {
10725 }
10727 /* (X | Y) & Y is (X, Y). */
10731 /* (X | Y) & X is (Y, X). */
10736 /* X & (X | Y) is (Y, X). */
10741 /* X & (Y | X) is (Y, X). */
10747 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10751 {
10757 }
10758 /* Fold ~X & 1 as (X & 1) == 0. */
10761 {
10767 }
10769 /* Fold (X ^ Y) & Y as ~X & Y. */
10772 {
10777 }
10778 /* Fold (X ^ Y) & X as ~Y & X. */
10782 {
10787 }
10788 /* Fold X & (X ^ Y) as X & ~Y. */
10791 {
10796 }
10797 /* Fold X & (Y ^ X) as ~Y & X. */
10801 {
10806 }
10811 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10814 {
10815 unsigned int prec
10822 }
10824 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10826 This results in more efficient code for machines without a NOR
10827 instruction. Combine will canonicalize to the first form
10828 which will allow use of NOR instructions provided by the
10829 backend if they exist. */
10832 {
10839 }
10841 /* If arg0 is derived from the address of an object or function, we may
10842 be able to fold this expression using the object or function's
10843 alignment. */
10845 {
10851 /* This works because modulus is a power of 2. If this weren't the
10852 case, we'd have to replace it by its greatest power-of-2
10853 divisor: modulus & -modulus. */
10856 }
10858 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
10859 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
10860 if the new mask might be further optimized. */
10869 {
10871 unsigned HOST_WIDE_INT mask
10881 {
10884 /* See if more bits can be proven as zero because of
10885 zero extension. */
10888 {
10893 {
10895 /* See if we can shorten the right shift. */
10898 }
10899 }
10903 /* For arithmetic shift if sign bit could be set, zerobits
10904 can contain actually sign bits, so no transformation is
10905 possible, unless MASK masks them all away. In that
10906 case the shift needs to be converted into logical shift. */
10909 {
10912 else
10914 }
10915 }
10917 /* ((X << 16) & 0xff00) is (X, 0). */
10923 {
10926 /* Only do the transformation if NEWMASK is some integer
10927 mode's mask. */
10934 {
10936 {
10942 }
10943 else
10947 newmask));
10948 }
10949 }
10950 }
10955 /* Don't touch a floating-point divide by zero unless the mode
10956 of the constant can represent infinity. */
10962 /* Optimize A / A to 1.0 if we don't care about
10963 NaNs or Infinities. Skip the transformation
10964 for non-real operands. */
10969 {
10973 }
10975 /* The complex version of the above A / A optimization. */
10978 {
10982 {
10984 /* omit_two_operands will call fold_convert for us. */
10986 }
10987 }
10989 /* (-A) / (-B) -> A / B */
10999 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11004 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11009 /* If ARG1 is a constant, we can convert this to a multiply by the
11010 reciprocal. This does not have the same rounding properties,
11011 so only do this if -freciprocal-math. We can actually
11012 always safely do it if ARG1 is a power of two, but it's hard to
11013 tell if it is or not in a portable manner. */
11015 {
11020 /* Find the reciprocal if optimizing and the result is exact. */
11022 {
11023 REAL_VALUE_TYPE r;
11026 {
11030 }
11031 }
11032 }
11033 /* Convert A/B/C to A/(B*C). */
11040 /* Convert A/(B/C) to (A/B)*C. */
11048 /* Convert C1/(X*C2) into (C1/C2)/X. */
11053 {
11059 }
11062 {
11066 /* Optimize sin(x)/cos(x) as tan(x). */
11072 {
11077 }
11079 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11085 {
11089 {
11093 }
11094 }
11096 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11097 NaNs or Infinities. */
11101 {
11108 {
11113 }
11114 }
11116 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11117 NaNs or Infinities. */
11121 {
11128 {
11132 {
11136 tmp);
11137 }
11138 }
11139 }
11141 /* Optimize pow(x,c)/x as pow(x,c-1). */
11145 {
11151 {
11153 REAL_VALUE_TYPE c;
11154 tree arg;
11160 }
11161 }
11163 /* Optimize a/root(b/c) into a*root(c/b). */
11165 {
11169 {
11178 }
11179 }
11181 /* Optimize x/expN(y) into x*expN(-y). */
11183 {
11188 }
11190 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11194 {
11201 }
11202 }
11207 /* Simplify A / (B << N) where A and B are positive and B is
11208 a power of 2, to A >> (N + log2(B)). */
11213 {
11216 {
11223 WARN_STRICT_OVERFLOW_MISC);
11229 }
11230 }
11232 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11233 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11239 /* Fall thru */
11248 /* X / -1 is -X. */
11255 /* Convert -A / -B to A / B when the type is signed and overflow is
11256 undefined. */
11260 {
11263 "when distributing negation across "
11265 WARN_STRICT_OVERFLOW_MISC);
11269 }
11273 {
11276 "when distributing negation across "
11278 WARN_STRICT_OVERFLOW_MISC);
11281 }
11283 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11284 operation, EXACT_DIV_EXPR.
11286 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11287 At one time others generated faster code, it's not clear if they do
11288 after the last round to changes to the DIV code in expmed.c. */
11297 {
11301 WARN_STRICT_OVERFLOW_MISC);
11303 }
11311 /* X % 1 is always zero, but be sure to preserve any side
11312 effects in X. */
11316 /* X % 0, return X % 0 unchanged so that we can get the
11317 proper warnings and errors. */
11321 /* 0 % X is always zero, but be sure to preserve any side
11322 effects in X. Place this after checking for X == 0. */
11326 /* X % -1 is zero. */
11333 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11334 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11339 {
11341 /* Also optimize A % (C << N) where C is a power of 2,
11342 to A & ((C << N) - 1). */
11347 {
11352 "occur when simplifying "
11354 WARN_STRICT_OVERFLOW_MISC);
11358 }
11359 }
11361 /* X % -C is the same as X % C. */
11368 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11373 /* X % -Y is the same as X % Y. */
11384 {
11388 WARN_STRICT_OVERFLOW_MISC);
11390 }
11401 /* Optimize -1 >> x for arithmetic right shifts. */
11404 /* ... fall through ... */
11407 shift:
11413 /* Since negative shift count is not well-defined,
11414 don't try to compute it in the compiler. */
11418 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11423 {
11427 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11428 being well defined. */
11430 {
11435 else
11437 }
11441 }
11443 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11444 into x & ((unsigned)-1 >> c) for unsigned types. */
11452 {
11455 tree lshift;
11456 tree arg00;
11459 {
11466 }
11467 }
11469 /* Rewrite an LROTATE_EXPR by a constant into an
11470 RROTATE_EXPR by a new constant. */
11472 {
11477 }
11479 /* If we have a rotate of a bit operation with the rotate count and
11480 the second operand of the bit operation both constant,
11481 permute the two operations. */
11493 /* Two consecutive rotates adding up to the precision of the
11494 type can be ignored. */
11505 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11506 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11507 if the latter can be further optimized. */
11512 {
11515 arg1);
11518 arg1);
11522 }
11550 /* Note that the operands of this must be ints
11551 and their values must be 0 or 1.
11552 ("true" is a fixed value perhaps depending on the language.) */
11553 /* If first arg is constant zero, return it. */
11557 /* If either arg is constant true, drop it. */
11561 /* Preserve sequence points. */
11564 /* If second arg is constant zero, result is zero, but first arg
11565 must be evaluated. */
11568 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11569 case will be handled here. */
11573 /* !X && X is always false. */
11577 /* X && !X is always false. */
11582 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11583 means A >= Y && A != MAX, but in this case we know that
11584 A < X <= MAX. */
11588 {
11596 }
11598 truth_andor:
11599 /* We only do these simplifications if we are optimizing. */
11603 /* Check for things like (A || B) && (A || C). We can convert this
11604 to A || (B && C). Note that either operator can be any of the four
11605 truth and/or operations and the transformation will still be
11606 valid. Also note that we only care about order for the
11607 ANDIF and ORIF operators. If B contains side effects, this
11608 might change the truth-value of A. */
11615 {
11635 /* This case if tricky because we must either have commutative
11636 operators or else A10 must not have side-effects. */
11642 a01);
11643 }
11645 /* See if we can build a range comparison. */
11649 /* Check for the possibility of merging component references. If our
11650 lhs is another similar operation, try to merge its rhs with our
11651 rhs. Then try to merge our lhs and rhs. */
11663 /* Note that the operands of this must be ints
11664 and their values must be 0 or true.
11665 ("true" is a fixed value perhaps depending on the language.) */
11666 /* If first arg is constant true, return it. */
11670 /* If either arg is constant zero, drop it. */
11674 /* Preserve sequence points. */
11677 /* If second arg is constant true, result is true, but we must
11678 evaluate first arg. */
11681 /* Likewise for first arg, but note this only occurs here for
11682 TRUTH_OR_EXPR. */
11686 /* !X || X is always true. */
11690 /* X || !X is always true. */
11698 /* If the second arg is constant zero, drop it. */
11701 /* If the second arg is constant true, this is a logical inversion. */
11703 {
11704 /* Only call invert_truthvalue if operand is a truth value. */
11707 else
11710 }
11711 /* Identical arguments cancel to zero. */
11715 /* !X ^ X is always true. */
11720 /* X ^ !X is always true. */
11733 /* bool_var != 0 becomes bool_var. */
11738 /* bool_var == 1 becomes bool_var. */
11743 /* bool_var != 1 becomes !bool_var. */
11748 /* bool_var == 0 becomes !bool_var. */
11753 /* If this is an equality comparison of the address of two non-weak,
11754 unaliased symbols neither of which are extern (since we do not
11755 have access to attributes for externs), then we know the result. */
11768 {
11769 /* We know that we're looking at the address of two
11770 non-weak, unaliased, static _DECL nodes.
11772 It is both wasteful and incorrect to call operand_equal_p
11773 to compare the two ADDR_EXPR nodes. It is wasteful in that
11774 all we need to do is test pointer equality for the arguments
11775 to the two ADDR_EXPR nodes. It is incorrect to use
11776 operand_equal_p as that function is NOT equivalent to a
11777 C equality test. It can in fact return false for two
11778 objects which would test as equal using the C equality
11779 operator. */
11783 type);
11784 }
11786 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11787 a MINUS_EXPR of a constant, we can convert it into a comparison with
11788 a revised constant as long as no overflow occurs. */
11800 /* Similarly for a NEGATE_EXPR. */
11808 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11817 /* Transform comparisons of the form X +- C CMP X. */
11823 {
11830 else
11833 }
11835 /* If we have X - Y == 0, we can convert that to X == Y and similarly
11836 for !=. Don't do this for ordered comparisons due to overflow. */
11842 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11847 /* If this is an EQ or NE comparison with zero and ARG0 is
11848 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11849 two operations, but the latter can be done in one less insn
11850 on machines that have only two-operand insns or on which a
11851 constant cannot be the first operand. */
11854 {
11859 {
11866 }
11869 {
11876 }
11877 }
11879 /* If this is an NE or EQ comparison of zero against the result of a
11880 signed MOD operation whose second operand is a power of 2, make
11881 the MOD operation unsigned since it is simpler and equivalent. */
11889 {
11899 }
11901 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11902 C1 is a valid shift constant, and C2 is a power of two, i.e.
11903 a single bit. */
11907 == INTEGER_CST
11910 {
11915 /* Check for a valid shift count. */
11918 {
11922 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11923 can be rewritten as (X & (C2 << C1)) != 0. */
11925 {
11929 }
11930 /* Otherwise, for signed (arithmetic) shifts,
11931 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11932 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11936 /* Otherwise, of unsigned (logical) shifts,
11937 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11938 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11939 else
11943 arg000);
11944 }
11945 }
11947 /* If this is an NE comparison of zero with an AND of one, remove the
11948 comparison since the AND will give the correct value. */
11955 /* If we have (A & C) == C where C is a power of 2, convert this into
11956 (A & C) != 0. Similarly for NE_EXPR. */
11962 integer_zero_node));
11964 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
11965 bit, then fold the expression into A < 0 or A >= 0. */
11970 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
11971 Similarly for NE_EXPR. */
11975 {
11984 }
11986 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
11987 Similarly for NE_EXPR. */
11991 {
11998 }
12000 /* Optimize comparisons of strlen vs zero to a compare of the
12001 first character of the string vs zero. To wit,
12002 strlen(ptr) == 0 => *ptr == 0
12003 strlen(ptr) != 0 => *ptr != 0
12004 Other cases should reduce to one of these two (or a constant)
12005 due to the return value of strlen being unsigned. */
12008 {
12016 {
12020 }
12021 }
12023 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12024 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12028 {
12035 {
12037 {
12040 }
12043 }
12044 }
12046 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12052 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12057 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12064 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12072 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12073 (X & C) == 0 when C is a single bit. */
12078 {
12084 }
12086 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12087 constant C is a power of two, i.e. a single bit. */
12094 {
12098 }
12100 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12101 when is C is a power of two, i.e. a single bit. */
12108 {
12114 }
12118 {
12121 }
12123 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12130 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12133 {
12145 arg01),
12153 arg01),
12161 arg00),
12169 arg00),
12171 }
12175 {
12182 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12183 operand_equal_p guarantees no side-effects so we don't need
12184 to use omit_one_operand on Z. */
12194 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12201 arg10);
12202 }
12204 /* Attempt to simplify equality/inequality comparisons of complex
12205 values. Only lower the comparison if the result is known or
12206 can be simplified to a single scalar comparison. */
12211 {
12216 {
12219 }
12220 else
12221 {
12224 }
12227 {
12230 }
12231 else
12232 {
12235 }
12239 {
12241 {
12246 }
12247 else
12248 {
12253 }
12254 }
12258 {
12260 {
12265 }
12266 else
12267 {
12272 }
12273 }
12274 }
12286 /* Transform comparisons of the form X +- C CMP X. */
12293 {
12300 else
12303 /* (X - c) > X becomes false. */
12307 {
12311 "occur when assuming that (X - c) > X "
12313 WARN_STRICT_OVERFLOW_ALL);
12315 }
12317 /* Likewise (X + c) < X becomes false. */
12321 {
12325 "occur when assuming that "
12327 WARN_STRICT_OVERFLOW_ALL);
12329 }
12331 /* Convert (X - c) <= X to true. */
12336 {
12340 "occur when assuming that "
12342 WARN_STRICT_OVERFLOW_ALL);
12344 }
12346 /* Convert (X + c) >= X to true. */
12351 {
12355 "occur when assuming that "
12357 WARN_STRICT_OVERFLOW_ALL);
12359 }
12362 {
12363 /* Convert X + c > X and X - c < X to true for integers. */
12367 {
12370 "not occur when assuming that "
12372 WARN_STRICT_OVERFLOW_ALL);
12374 }
12379 {
12382 "not occur when assuming that "
12384 WARN_STRICT_OVERFLOW_ALL);
12386 }
12388 /* Convert X + c <= X and X - c >= X to false for integers. */
12392 {
12395 "not occur when assuming that "
12397 WARN_STRICT_OVERFLOW_ALL);
12399 }
12404 {
12407 "not occur when assuming that "
12409 WARN_STRICT_OVERFLOW_ALL);
12411 }
12412 }
12413 }
12415 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
12416 This transformation affects the cases which are handled in later
12417 optimizations involving comparisons with non-negative constants. */
12421 {
12423 {
12428 }
12430 {
12435 }
12436 }
12438 /* Comparisons with the highest or lowest possible integer of
12439 the specified precision will have known values. */
12440 {
12448 {
12449 HOST_WIDE_INT signed_max_hi;
12454 {
12461 {
12465 }
12466 else
12467 {
12471 }
12472 }
12473 else
12474 {
12483 {
12486 }
12487 else
12488 {
12491 }
12492 }
12497 {
12510 /* The GE_EXPR and LT_EXPR cases above are not normally
12511 reached because of previous transformations. */
12515 }
12517 == max_hi
12520 {
12526 arg1);
12532 arg1);
12535 }
12537 == min_hi
12540 {
12555 }
12557 == min_hi
12560 {
12565 arg1);
12570 arg1);
12573 }
12578 /* We will flip the signedness of the comparison operator
12579 associated with the mode of arg1, so the sign bit is
12580 specified by this mode. Check that arg1 is the signed
12581 max associated with this sign bit. */
12583 /* signed_type does not work on pointer types. */
12585 {
12586 /* The following case also applies to X < signed_max+1
12587 and X >= signed_max+1 because previous transformations. */
12589 {
12590 tree st;
12595 }
12596 }
12597 }
12598 }
12600 /* If we are comparing an ABS_EXPR with a constant, we can
12601 convert all the cases into explicit comparisons, but they may
12602 well not be faster than doing the ABS and one comparison.
12603 But ABS (X) <= C is a range comparison, which becomes a subtraction
12604 and a comparison, and is probably faster. */
12618 /* Convert ABS_EXPR<x> >= 0 to true. */
12625 {
12628 "when simplifying comparison of "
12630 WARN_STRICT_OVERFLOW_CONDITIONAL);
12632 }
12634 /* Convert ABS_EXPR<x> < 0 to false. */
12639 {
12642 "when simplifying comparison of "
12644 WARN_STRICT_OVERFLOW_CONDITIONAL);
12646 }
12648 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12649 and similarly for >= into !=. */
12664 return
12683 {
12687 }
12689 /* If the first operand is NaN, the result is constant. */
12693 {
12695 ? integer_zero_node
12698 }
12700 /* If the second operand is NaN, the result is constant. */
12704 {
12706 ? integer_zero_node
12709 }
12711 /* Simplify unordered comparison of something with itself. */
12717 && !flag_trapping_math
12721 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12722 {
12733 }
12738 /* When pedantic, a compound expression can be neither an lvalue
12739 nor an integer constant expression. */
12742 /* Don't let (0, 0) be null pointer constant. */
12756 /* An ASSERT_EXPR should never be passed to fold_binary. */
12762 }
12764 /* Callback for walk_tree, looking for LABEL_EXPR.
12765 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12766 Do not check the sub-tree of GOTO_EXPR. */
12768 static tree
12772 {
12774 {
12779 /* no break */
12782 }
12783 }
12785 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12786 accessible from outside the sub-tree. Returns NULL_TREE if no
12787 addressable label is found. */
12789 static bool
12791 {
12793 }
12795 /* Fold a ternary expression of code CODE and type TYPE with operands
12796 OP0, OP1, and OP2. Return the folded expression if folding is
12797 successful. Otherwise, return NULL_TREE. */
12799 tree
12801 {
12802 tree tem;
12809 /* Strip any conversions that don't change the mode. This is safe
12810 for every expression, except for a comparison expression because
12811 its signedness is derived from its operands. So, in the latter
12812 case, only strip conversions that don't change the signedness.
12814 Note that this is done as an internal manipulation within the
12815 constant folder, in order to find the simplest representation of
12816 the arguments so that their form can be studied. In any cases,
12817 the appropriate type conversions should be put back in the tree
12818 that will get out of the constant folder. */
12820 {
12823 }
12826 {
12829 }
12832 {
12836 {
12842 }
12846 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12847 so all simple results must be passed through pedantic_non_lvalue. */
12849 {
12852 /* Only optimize constant conditions when the selected branch
12853 has the same type as the COND_EXPR. This avoids optimizing
12854 away "c ? x : throw", where the throw has a void type.
12855 Avoid throwing away that operand which contains label. */
12862 }
12866 /* If we have A op B ? A : C, we may be able to convert this to a
12867 simpler expression, depending on the operation and the values
12868 of B and C. Signed zeros prevent all of these transformations,
12869 for reasons given above each one.
12871 Also try swapping the arguments and inverting the conditional. */
12876 {
12880 }
12884 op2,
12887 {
12890 {
12894 }
12895 }
12897 /* If the second operand is simpler than the third, swap them
12898 since that produces better jump optimization results. */
12901 {
12902 /* See if this can be inverted. If it can't, possibly because
12903 it was a floating-point inequality comparison, don't do
12904 anything. */
12908 }
12910 /* Convert A ? 1 : 0 to simply A. */
12913 /* If we try to convert OP0 to our type, the
12914 call to fold will try to move the conversion inside
12915 a COND, which will recurse. In that case, the COND_EXPR
12916 is probably the best choice, so leave it alone. */
12920 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12921 over COND_EXPR in cases such as floating point comparisons. */
12928 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12933 {
12934 /* sign_bit_p only checks ARG1 bits within A's precision.
12935 If <sign bit of A> has wider type than A, bits outside
12936 of A's precision in <sign bit of A> need to be checked.
12937 If they are all 0, this optimization needs to be done
12938 in unsigned A's type, if they are all 1 in signed A's type,
12939 otherwise this can't be done. */
12944 {
12946 HOST_WIDE_INT mask_hi;
12948 tree tem_type;
12956 {
12960 }
12961 else
12962 {
12966 }
12968 {
12972 }
12973 else
12979 {
12982 }
12985 {
12988 }
12989 else
12991 }
12998 arg1)));
12999 }
13001 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13002 already handled above. */
13007 {
13016 }
13018 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13019 is probably obsolete because the first operand should be a
13020 truth value (that's why we have the two cases above), but let's
13021 leave it in until we can confirm this for all front-ends. */
13032 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13038 arg1);
13040 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13044 {
13045 /* Only perform transformation if ARG0 is easily inverted. */
13050 arg1);
13051 }
13053 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13057 {
13058 /* Only perform transformation if ARG0 is easily inverted. */
13063 op2);
13064 }
13066 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13072 op2);
13077 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13078 of fold_ternary on them. */
13085 {
13094 {
13099 else
13100 {
13102 tree value;
13106 }
13111 else
13113 }
13114 }
13120 }
13122 /* Perform constant folding and related simplification of EXPR.
13123 The related simplifications include x*1 => x, x*0 => 0, etc.,
13124 and application of the associative law.
13125 NOP_EXPR conversions may be removed freely (as long as we
13126 are careful not to change the type of the overall expression).
13127 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13128 but we can constant-fold them if they have constant operands. */
13130 #ifdef ENABLE_FOLD_CHECKING
13131 # define fold(x) fold_1 (x)
13133 static
13134 #endif
13135 tree
13137 {
13141 tree tem;
13143 /* Return right away if a constant. */
13147 /* CALL_EXPR-like objects with variable numbers of operands are
13148 treated specially. */
13150 {
13152 {
13155 }
13157 }
13161 {
13166 {
13184 }
13185 }
13188 {
13190 {
13197 {
13202 /* Find a matching index by means of a binary search. */
13204 {
13220 else
13222 }
13223 }
13226 }
13234 }
13236 #ifdef ENABLE_FOLD_CHECKING
13237 #undef fold
13243 /* When --enable-checking=fold, compute a digest of expr before
13244 and after actual fold call to see if fold did not accidentally
13245 change original expr. */
13247 tree
13249 {
13250 tree ret;
13253 htab_t ht;
13272 }
13274 void
13276 {
13279 htab_t ht;
13289 }
13291 static void
13293 {
13295 }
13297 static void
13299 {
13305 recursive_label:
13319 {
13320 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13324 }
13329 {
13330 /* Allow these fields to be modified. */
13331 tree tmp;
13338 {
13341 }
13342 }
13351 {
13354 {
13368 }
13372 {
13385 }
13402 {
13408 }
13413 {
13417 }
13428 {
13431 }
13441 }
13442 }
13444 /* Helper function for outputting the checksum of a tree T. When
13445 debugging with gdb, you can "define mynext" to be "next" followed
13446 by "call debug_fold_checksum (op0)", then just trace down till the
13447 outputs differ. */
13449 void
13451 {
13466 }
13468 #endif
13470 /* Fold a unary tree expression with code CODE of type TYPE with an
13471 operand OP0. Return a folded expression if successful. Otherwise,
13472 return a tree expression with code CODE of type TYPE with an
13473 operand OP0. */
13475 tree
13477 {
13478 tree tem;
13479 #ifdef ENABLE_FOLD_CHECKING
13482 htab_t ht;
13489 #endif
13495 #ifdef ENABLE_FOLD_CHECKING
13503 #endif
13505 }
13507 /* Fold a binary tree expression with code CODE of type TYPE with
13508 operands OP0 and OP1. Return a folded expression if successful.
13509 Otherwise, return a tree expression with code CODE of type TYPE
13510 with operands OP0 and OP1. */
13512 tree
13514 MEM_STAT_DECL)
13515 {
13516 tree tem;
13517 #ifdef ENABLE_FOLD_CHECKING
13523 htab_t ht;
13535 #endif
13541 #ifdef ENABLE_FOLD_CHECKING
13557 #endif
13559 }
13561 /* Fold a ternary tree expression with code CODE of type TYPE with
13562 operands OP0, OP1, and OP2. Return a folded expression if
13563 successful. Otherwise, return a tree expression with code CODE of
13564 type TYPE with operands OP0, OP1, and OP2. */
13566 tree
13568 MEM_STAT_DECL)
13569 {
13570 tree tem;
13571 #ifdef ENABLE_FOLD_CHECKING
13579 htab_t ht;
13596 #endif
13603 #ifdef ENABLE_FOLD_CHECKING
13627 #endif
13629 }
13631 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13632 arguments in ARGARRAY, and a null static chain.
13633 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13634 of type TYPE from the given operands as constructed by build_call_array. */
13636 tree
13638 {
13639 tree tem;
13640 #ifdef ENABLE_FOLD_CHECKING
13646 htab_t ht;
13660 #endif
13664 #ifdef ENABLE_FOLD_CHECKING
13681 #endif
13683 }
13685 /* Perform constant folding and related simplification of initializer
13686 expression EXPR. These behave identically to "fold_buildN" but ignore
13687 potential run-time traps and exceptions that fold must preserve. */
13689 #define START_FOLD_INIT \
13690 int saved_signaling_nans = flag_signaling_nans;\
13691 int saved_trapping_math = flag_trapping_math;\
13692 int saved_rounding_math = flag_rounding_math;\
13693 int saved_trapv = flag_trapv;\
13694 int saved_folding_initializer = folding_initializer;\
13695 flag_signaling_nans = 0;\
13696 flag_trapping_math = 0;\
13697 flag_rounding_math = 0;\
13698 flag_trapv = 0;\
13699 folding_initializer = 1;
13701 #define END_FOLD_INIT \
13702 flag_signaling_nans = saved_signaling_nans;\
13703 flag_trapping_math = saved_trapping_math;\
13704 flag_rounding_math = saved_rounding_math;\
13705 flag_trapv = saved_trapv;\
13706 folding_initializer = saved_folding_initializer;
13708 tree
13710 {
13711 tree result;
13712 START_FOLD_INIT;
13716 END_FOLD_INIT;
13718 }
13720 tree
13722 {
13723 tree result;
13724 START_FOLD_INIT;
13728 END_FOLD_INIT;
13730 }
13732 tree
13734 tree op2)
13735 {
13736 tree result;
13737 START_FOLD_INIT;
13741 END_FOLD_INIT;
13743 }
13745 tree
13748 {
13749 tree result;
13750 START_FOLD_INIT;
13754 END_FOLD_INIT;
13756 }
13758 #undef START_FOLD_INIT
13759 #undef END_FOLD_INIT
13761 /* Determine if first argument is a multiple of second argument. Return 0 if
13762 it is not, or we cannot easily determined it to be.
13764 An example of the sort of thing we care about (at this point; this routine
13765 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13766 fold cases do now) is discovering that
13768 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13770 is a multiple of
13772 SAVE_EXPR (J * 8)
13774 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13776 This code also handles discovering that
13778 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13780 is a multiple of 8 so we don't have to worry about dealing with a
13781 possible remainder.
13783 Note that we *look* inside a SAVE_EXPR only to determine how it was
13784 calculated; it is not safe for fold to do much of anything else with the
13785 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13786 at run time. For example, the latter example above *cannot* be implemented
13787 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13788 evaluation time of the original SAVE_EXPR is not necessarily the same at
13789 the time the new expression is evaluated. The only optimization of this
13790 sort that would be valid is changing
13792 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13794 divided by 8 to
13796 SAVE_EXPR (I) * SAVE_EXPR (J)
13798 (where the same SAVE_EXPR (J) is used in the original and the
13799 transformed version). */
13801 int
13803 {
13811 {
13813 /* Bitwise and provides a power of two multiple. If the mask is
13814 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13817 /* FALLTHRU */
13830 {
13834 /* const_binop may not detect overflow correctly,
13835 so check for it explicitly here. */
13841 size_one_node,
13845 }
13849 /* Can't handle conversions from non-integral or wider integral type. */
13855 /* .. fall through ... */
13872 }
13873 }
13875 /* Return true if CODE or TYPE is known to be non-negative. */
13877 static bool
13879 {
13882 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13883 have a signed:1 type (where the value is -1 and 0). */
13886 }
13888 /* Return true if (CODE OP0) is known to be non-negative. If the return
13889 value is based on the assumption that signed overflow is undefined,
13890 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13891 *STRICT_OVERFLOW_P. */
13893 bool
13896 {
13901 {
13903 /* We can't return 1 if flag_wrapv is set because
13904 ABS_EXPR<INT_MIN> = INT_MIN. */
13908 {
13911 }
13918 strict_overflow_p);
13921 {
13926 {
13929 strict_overflow_p);
13931 {
13935 strict_overflow_p);
13936 }
13937 }
13939 {
13942 strict_overflow_p);
13946 }
13947 }
13952 }
13954 /* We don't know sign of `t', so be conservative and return false. */
13956 }
13958 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13959 value is based on the assumption that signed overflow is undefined,
13960 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13961 *STRICT_OVERFLOW_P. */
13963 bool
13966 {
13971 {
13976 strict_overflow_p)
13978 strict_overflow_p));
13980 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13981 both unsigned and at least 2 bits shorter than the result. */
13985 {
13990 {
13994 }
13995 }
14000 {
14001 /* x * x for floating point x is always non-negative. */
14005 strict_overflow_p)
14007 strict_overflow_p));
14008 }
14010 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14011 both unsigned and their total bits is shorter than the result. */
14015 {
14022 }
14028 strict_overflow_p)
14030 strict_overflow_p));
14041 strict_overflow_p)
14043 strict_overflow_p));
14050 strict_overflow_p);
14053 }
14055 /* We don't know sign of `t', so be conservative and return false. */
14057 }
14059 /* Return true if T is known to be non-negative. If the return
14060 value is based on the assumption that signed overflow is undefined,
14061 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14062 *STRICT_OVERFLOW_P. */
14064 bool
14066 {
14071 {
14073 /* Query VRP to see if it has recorded any information about
14074 the range of this object. */
14088 strict_overflow_p)
14090 strict_overflow_p));
14094 }
14095 /* We don't know sign of `t', so be conservative and return false. */
14097 }
14099 /* Return true if T is known to be non-negative. If the return
14100 value is based on the assumption that signed overflow is undefined,
14101 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14102 *STRICT_OVERFLOW_P. */
14104 bool
14107 {
14110 {
14128 /* Always true. */
14132 /* sqrt(-0.0) is -0.0. */
14136 strict_overflow_p);
14169 /* True if the 1st argument is nonnegative. */
14171 strict_overflow_p);
14174 /* True if the 1st OR 2nd arguments are nonnegative. */
14176 strict_overflow_p)
14178 strict_overflow_p)));
14181 /* True if the 1st AND 2nd arguments are nonnegative. */
14183 strict_overflow_p)
14185 strict_overflow_p)));
14188 /* True if the 2nd argument is nonnegative. */
14190 strict_overflow_p);
14193 /* True if the 1st argument is nonnegative or the second
14194 argument is an even integer. */
14199 strict_overflow_p);
14202 /* True if the 1st argument is nonnegative or the second
14203 argument is an even integer valued real. */
14205 {
14206 REAL_VALUE_TYPE c;
14207 HOST_WIDE_INT n;
14212 {
14213 REAL_VALUE_TYPE cint;
14218 }
14219 }
14221 strict_overflow_p);
14225 }
14227 type);
14228 }
14230 /* Return true if T is known to be non-negative. If the return
14231 value is based on the assumption that signed overflow is undefined,
14232 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14233 *STRICT_OVERFLOW_P. */
14235 bool
14237 {
14243 {
14245 {
14249 /* If the initializer is non-void, then it's a normal expression
14250 that will be assigned to the slot. */
14254 /* Otherwise, the initializer sets the slot in some way. One common
14255 way is an assignment statement at the end of the initializer. */
14257 {
14265 else
14267 }
14272 strict_overflow_p);
14275 }
14278 {
14285 arg0,
14286 arg1,
14287 strict_overflow_p);
14288 }
14293 strict_overflow_p);
14296 strict_overflow_p);
14299 strict_overflow_p);
14304 }
14306 /* We don't know sign of `t', so be conservative and return false. */
14308 }
14310 /* Return true if T is known to be non-negative. If the return
14311 value is based on the assumption that signed overflow is undefined,
14312 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14313 *STRICT_OVERFLOW_P. */
14315 bool
14317 {
14324 {
14331 strict_overflow_p);
14337 strict_overflow_p);
14346 }
14349 {
14357 strict_overflow_p);
14362 strict_overflow_p);
14377 }
14378 }
14380 /* Return true if `t' is known to be non-negative. Handle warnings
14381 about undefined signed overflow. */
14383 bool
14385 {
14392 "determining that expression is always "
14394 WARN_STRICT_OVERFLOW_MISC);
14396 }
14399 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14400 For floating point we further ensure that T is not denormal.
14401 Similar logic is present in nonzero_address in rtlanal.h.
14403 If the return value is based on the assumption that signed overflow
14404 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14405 change *STRICT_OVERFLOW_P. */
14407 bool
14410 {
14412 {
14415 strict_overflow_p);
14418 {
14424 strict_overflow_p));
14425 }
14430 strict_overflow_p);
14434 }
14437 }
14439 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14440 For floating point we further ensure that T is not denormal.
14441 Similar logic is present in nonzero_address in rtlanal.h.
14443 If the return value is based on the assumption that signed overflow
14444 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14445 change *STRICT_OVERFLOW_P. */
14447 bool
14449 tree type,
14450 tree op0,
14452 {
14455 {
14459 {
14460 /* With the presence of negative values it is hard
14461 to say something. */
14468 /* One of operands must be positive and the other non-negative. */
14469 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14470 overflows, on a twos-complement machine the sum of two
14471 nonnegative numbers can never be zero. */
14473 strict_overflow_p)
14475 strict_overflow_p));
14476 }
14481 {
14483 strict_overflow_p)
14485 strict_overflow_p))
14486 {
14489 }
14490 }
14499 {
14502 }
14509 {
14513 /* When both operands are nonzero, then MAX must be too. */
14515 strict_overflow_p))
14518 /* MAX where operand 0 is positive is positive. */
14520 strict_overflow_p);
14521 }
14522 /* MAX where operand 1 is positive is positive. */
14527 {
14531 }
14536 strict_overflow_p)
14538 strict_overflow_p));
14542 }
14545 }
14547 /* Return true when T is an address and is known to be nonzero.
14548 For floating point we further ensure that T is not denormal.
14549 Similar logic is present in nonzero_address in rtlanal.h.
14551 If the return value is based on the assumption that signed overflow
14552 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14553 change *STRICT_OVERFLOW_P. */
14555 bool
14557 {
14560 {
14562 /* Query VRP to see if it has recorded any information about
14563 the range of this object. */
14570 {
14576 /* Weak declarations may link to NULL. */
14580 /* Constants are never weak. */
14585 }
14593 {
14597 }
14602 }
14604 }
14606 /* Return true when T is an address and is known to be nonzero.
14607 For floating point we further ensure that T is not denormal.
14608 Similar logic is present in nonzero_address in rtlanal.h.
14610 If the return value is based on the assumption that signed overflow
14611 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14612 change *STRICT_OVERFLOW_P. */
14614 bool
14616 {
14620 /* Doing something useful for floating point would need more work. */
14626 {
14629 strict_overflow_p);
14635 strict_overflow_p);
14643 }
14646 {
14649 strict_overflow_p);
14657 strict_overflow_p);
14675 strict_overflow_p);
14679 strict_overflow_p);
14686 }
14688 }
14690 /* Return true when T is an address and is known to be nonzero.
14691 Handle warnings about undefined signed overflow. */
14693 bool
14695 {
14702 "determining that expression is always "
14704 WARN_STRICT_OVERFLOW_MISC);
14706 }
14708 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14709 attempt to fold the expression to a constant without modifying TYPE,
14710 OP0 or OP1.
14712 If the expression could be simplified to a constant, then return
14713 the constant. If the expression would not be simplified to a
14714 constant, then return NULL_TREE. */
14716 tree
14718 {
14721 }
14723 /* Given the components of a unary expression CODE, TYPE and OP0,
14724 attempt to fold the expression to a constant without modifying
14725 TYPE or OP0.
14727 If the expression could be simplified to a constant, then return
14728 the constant. If the expression would not be simplified to a
14729 constant, then return NULL_TREE. */
14731 tree
14733 {
14736 }
14738 /* If EXP represents referencing an element in a constant string
14739 (either via pointer arithmetic or array indexing), return the
14740 tree representing the value accessed, otherwise return NULL. */
14742 tree
14744 {
14748 {
14750 tree index;
14751 tree string;
14755 else
14756 {
14760 /* Optimize the special-case of a zero lower bound.
14762 We convert the low_bound to sizetype to avoid some problems
14763 with constant folding. (E.g. suppose the lower bound is 1,
14764 and its mode is QI. Without the conversion,l (ARRAY
14765 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14766 +INDEX), which becomes (ARRAY+255+INDEX). Opps!) */
14771 }
14784 }
14786 }
14788 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14789 an integer constant, real, or fixed-point constant.
14791 TYPE is the type of the result. */
14793 static tree
14795 {
14799 {
14801 {
14803 HOST_WIDE_INT high;
14811 }
14818 {
14819 FIXED_VALUE_TYPE f;
14824 /* Propagate overflow flags. */
14826 {
14829 }
14833 }
14837 }
14840 }
14842 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14843 an integer constant or real constant.
14845 TYPE is the type of the result. */
14847 tree
14849 {
14853 {
14855 /* If the value is unsigned, then the absolute value is
14856 the same as the ordinary value. */
14859 /* Similarly, if the value is non-negative. */
14862 /* If the value is negative, then the absolute value is
14863 its negation. */
14864 else
14865 {
14867 HOST_WIDE_INT high;
14873 }
14879 else
14885 }
14888 }
14890 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14891 constant. TYPE is the type of the result. */
14893 static tree
14895 {
14905 }
14907 /* Given CODE, a relational operator, the target type, TYPE and two
14908 constant operands OP0 and OP1, return the result of the
14909 relational operation. If the result is not a compile time
14910 constant, then return NULL_TREE. */
14912 static tree
14914 {
14917 /* From here on, the only cases we handle are when the result is
14918 known to be a constant. */
14921 {
14925 /* Handle the cases where either operand is a NaN. */
14927 {
14929 {
14957 }
14960 }
14963 }
14966 {
14970 }
14972 /* Handle equality/inequality of complex constants. */
14974 {
14985 else
14987 }
14989 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14991 To compute GT, swap the arguments and do LT.
14992 To compute GE, do LT and invert the result.
14993 To compute LE, swap the arguments, do LT and invert the result.
14994 To compute NE, do EQ and invert the result.
14996 Therefore, the code below must handle only EQ and LT. */
14999 {
15004 }
15006 /* Note that it is safe to invert for real values here because we
15007 have already handled the one case that it matters. */
15011 {
15014 }
15016 /* Compute a result for LT or EQ if args permit;
15017 Otherwise return T. */
15019 {
15024 else
15026 }
15027 else
15033 }
15035 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15036 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15037 itself. */
15039 tree
15041 {
15042 /* If the expression does not have side effects then we don't have to wrap
15043 it with a cleanup point expression. */
15047 /* If the expression is a return, check to see if the expression inside the
15048 return has no side effects or the right hand side of the modify expression
15049 inside the return. If either don't have side effects set we don't need to
15050 wrap the expression in a cleanup point expression. Note we don't check the
15051 left hand side of the modify because it should always be a return decl. */
15053 {
15060 }
15063 }
15065 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15066 of an indirection through OP0, or NULL_TREE if no simplification is
15067 possible. */
15069 tree
15071 {
15073 tree subtype;
15081 {
15084 /* *&CONST_DECL -> to the value of the const decl. */
15087 /* *&p => p; make sure to handle *&"str"[cst] here. */
15089 {
15093 else
15095 }
15096 /* *(foo *)&fooarray => fooarray[0] */
15099 {
15105 }
15106 /* *(foo *)&complexfoo => __real__ complexfoo */
15110 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15113 {
15117 }
15118 }
15120 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15123 {
15126 tree op00type;
15133 {
15144 }
15145 }
15148 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15151 {
15154 tree op00type;
15161 {
15165 }
15166 }
15168 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15171 {
15172 tree type_domain;
15179 }
15182 }
15184 /* Builds an expression for an indirection through T, simplifying some
15185 cases. */
15187 tree
15189 {
15195 else
15197 }
15199 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15201 tree
15203 {
15208 else
15210 }
15212 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15213 whose result is ignored. The type of the returned tree need not be
15214 the same as the original expression. */
15216 tree
15218 {
15224 {
15235 else
15241 {
15257 }
15262 }
15263 }
15265 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15266 This can only be applied to objects of a sizetype. */
15268 tree
15270 {
15277 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15278 have to do anything. Only do this when we are not given a const,
15279 because in that case, this check is more expensive than just
15280 doing it. */
15282 {
15287 }
15289 /* If divisor is a power of two, simplify this to bit manipulation. */
15291 {
15293 {
15306 {
15307 high++;
15310 }
15314 }
15315 else
15316 {
15317 tree t;
15323 }
15324 }
15325 else
15326 {
15331 }
15334 }
15336 /* Likewise, but round down. */
15338 tree
15340 {
15347 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15348 have to do anything. Only do this when we are not given a const,
15349 because in that case, this check is more expensive than just
15350 doing it. */
15352 {
15357 }
15359 /* If divisor is a power of two, simplify this to bit manipulation. */
15361 {
15362 tree t;
15366 }
15367 else
15368 {
15373 }
15376 }
15378 /* Returns the pointer to the base of the object addressed by EXP and
15379 extracts the information about the offset of the access, storing it
15380 to PBITPOS and POFFSET. */
15382 static tree
15385 {
15386 tree core;
15389 HOST_WIDE_INT bitsize;
15392 {
15397 }
15398 else
15399 {
15403 }
15406 }
15408 /* Returns true if addresses of E1 and E2 differ by a constant, false
15409 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15411 bool
15413 {
15427 {
15437 }
15439 {
15440 /* If only one of the offsets is non-constant, the difference cannot
15441 be a constant. */
15443 }
15444 else
15449 }
15451 /* Simplify the floating point expression EXP when the sign of the
15452 result is not significant. Return NULL_TREE if no simplification
15453 is possible. */
15455 tree
15457 {
15461 {
15496 {
15499 {
15501 /* Strip copysign function call, return the 1st argument. */
15507 /* Strip sign ops from the argument of "odd" math functions. */
15509 {
15513 }
15515 }
15516 }
15521 }
15523 }