| blob | 8dddca19c08874c859ad3cc39e5c2d08aa319f2a |
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. */
70 /* Nonzero if we are folding constants inside an initializer; zero
71 otherwise. */
74 /* The following constants represent a bit based encoding of GCC's
75 comparison operators. This encoding simplifies transformations
76 on relational comparison operators, such as AND and OR. */
94 };
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)), adjust the quotient. */
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. */
1895 }
1898 {
1899 FIXED_VALUE_TYPE f1;
1900 FIXED_VALUE_TYPE f2;
1901 FIXED_VALUE_TYPE result;
1906 /* The following codes are handled by fixed_arithmetic. */
1908 {
1925 }
1932 /* Propagate overflow flags. */
1934 {
1937 }
1941 }
1944 {
1953 {
1964 notrunc);
1968 notrunc);
1972 {
1973 tree magsquared
1977 notrunc);
1978 tree t1
1982 notrunc);
1983 tree t2
1987 notrunc);
1994 }
1999 }
2003 }
2006 }
2008 /* Create a size type INT_CST node with NUMBER sign extended. KIND
2009 indicates which particular sizetype to create. */
2011 tree
2013 {
2015 }
2016 \f
2017 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2018 is a tree code. The type of the result is taken from the operands.
2019 Both must be equivalent integer types, ala int_binop_types_match_p.
2020 If the operands are constant, so is the result. */
2022 tree
2024 {
2033 /* Handle the special case of two integer constants faster. */
2035 {
2036 /* And some specific cases even faster than that. */
2038 {
2043 }
2045 {
2048 }
2050 {
2053 }
2055 /* Handle general case of two integer constants. */
2057 }
2060 }
2062 /* Given two values, either both of sizetype or both of bitsizetype,
2063 compute the difference between the two values. Return the value
2064 in signed type corresponding to the type of the operands. */
2066 tree
2068 {
2070 tree ctype;
2075 /* If the type is already signed, just do the simple thing. */
2083 else
2086 /* If either operand is not a constant, do the conversions to the signed
2087 type and subtract. The hardware will do the right thing with any
2088 overflow in the subtraction. */
2093 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2094 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2095 overflow) and negate (which can't either). Special-case a result
2096 of zero while we're here. */
2101 else
2105 }
2106 \f
2107 /* A subroutine of fold_convert_const handling conversions of an
2108 INTEGER_CST to another integer type. */
2110 static tree
2112 {
2113 tree t;
2115 /* Given an integer constant, make new constant with new type,
2116 appropriately sign-extended or truncated. */
2119 /* Don't set the overflow when
2120 converting from a pointer, */
2122 /* or to a sizetype with same signedness
2123 and the precision is unchanged.
2124 ??? sizetype is always sign-extended,
2125 but its signedness depends on the
2126 frontend. Thus we see spurious overflows
2127 here if we do not check this. */
2142 }
2144 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2145 to an integer type. */
2147 static tree
2149 {
2151 tree t;
2153 /* The following code implements the floating point to integer
2154 conversion rules required by the Java Language Specification,
2155 that IEEE NaNs are mapped to zero and values that overflow
2156 the target precision saturate, i.e. values greater than
2157 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2158 are mapped to INT_MIN. These semantics are allowed by the
2159 C and C++ standards that simply state that the behavior of
2160 FP-to-integer conversion is unspecified upon overflow. */
2163 REAL_VALUE_TYPE r;
2167 {
2174 }
2176 /* If R is NaN, return zero and show we have an overflow. */
2178 {
2182 }
2184 /* See if R is less than the lower bound or greater than the
2185 upper bound. */
2188 {
2192 {
2196 }
2197 }
2200 {
2203 {
2206 {
2210 }
2211 }
2212 }
2220 }
2222 /* A subroutine of fold_convert_const handling conversions of a
2223 FIXED_CST to an integer type. */
2225 static tree
2227 {
2228 tree t;
2232 /* Right shift FIXED_CST to temp by fbit. */
2236 {
2241 /* Left shift temp to temp_trunc by fbit. */
2246 }
2247 else
2248 {
2253 }
2255 /* If FIXED_CST is negative, we need to round the value toward 0.
2256 By checking if the fractional bits are not zero to add 1 to temp. */
2259 {
2260 double_int one;
2264 }
2266 /* Given a fixed-point constant, make new constant with new type,
2267 appropriately sign-extended or truncated. */
2275 }
2277 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2278 to another floating point type. */
2280 static tree
2282 {
2283 REAL_VALUE_TYPE value;
2284 tree t;
2291 }
2293 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2294 to a floating point type. */
2296 static tree
2298 {
2299 REAL_VALUE_TYPE value;
2300 tree t;
2309 }
2311 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2312 to another fixed-point type. */
2314 static tree
2316 {
2317 FIXED_VALUE_TYPE value;
2318 tree t;
2325 /* Propagate overflow flags. */
2327 {
2330 }
2334 }
2336 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2337 to a fixed-point type. */
2339 static tree
2341 {
2342 FIXED_VALUE_TYPE value;
2343 tree t;
2352 /* Propagate overflow flags. */
2354 {
2357 }
2361 }
2363 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2364 to a fixed-point type. */
2366 static tree
2368 {
2369 FIXED_VALUE_TYPE value;
2370 tree t;
2378 /* Propagate overflow flags. */
2380 {
2383 }
2387 }
2389 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2390 type TYPE. If no simplification can be done return NULL_TREE. */
2392 static tree
2394 {
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 {
2692 /* Assume the worst for front-end tree codes. */
2696 }
2699 }
2701 /* Return an expr equal to X but certainly not valid as an lvalue. */
2703 tree
2705 {
2706 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2707 us. */
2714 }
2716 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2717 Zero means allow extended lvalues. */
2721 /* When pedantic, return an expr equal to X but certainly not valid as a
2722 pedantic lvalue. Otherwise, return X. */
2724 static tree
2726 {
2729 else
2731 }
2732 \f
2733 /* Given a tree comparison code, return the code that is the logical inverse
2734 of the given code. It is not safe to do this for floating-point
2735 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2736 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2738 enum tree_code
2740 {
2745 {
2776 }
2777 }
2779 /* Similar, but return the comparison that results if the operands are
2780 swapped. This is safe for floating-point. */
2782 enum tree_code
2784 {
2786 {
2812 }
2813 }
2816 /* Convert a comparison tree code from an enum tree_code representation
2817 into a compcode bit-based encoding. This function is the inverse of
2818 compcode_to_comparison. */
2820 static enum comparison_code
2822 {
2824 {
2855 }
2856 }
2858 /* Convert a compcode bit-based encoding of a comparison operator back
2859 to GCC's enum tree_code representation. This function is the
2860 inverse of comparison_to_compcode. */
2862 static enum tree_code
2864 {
2866 {
2897 }
2898 }
2900 /* Return a tree for the comparison which is the combination of
2901 doing the AND or OR (depending on CODE) of the two operations LCODE
2902 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2903 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2904 if this makes the transformation invalid. */
2906 tree
2910 {
2917 {
2928 }
2931 {
2932 /* Eliminate unordered comparisons, as well as LTGT and ORD
2933 which are not used unless the mode has NaNs. */
2939 }
2941 {
2942 /* Check that the original operation and the optimized ones will trap
2943 under the same condition. */
2954 /* In a short-circuited boolean expression the LHS might be
2955 such that the RHS, if evaluated, will never trap. For
2956 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2957 if neither x nor y is NaN. (This is a mixed blessing: for
2958 example, the expression above will never trap, hence
2959 optimizing it to x < y would be invalid). */
2964 /* If the comparison was short-circuited, and only the RHS
2965 trapped, we may now generate a spurious trap. */
2970 /* If we changed the conditions that cause a trap, we lose. */
2973 }
2979 else
2982 }
2983 \f
2984 /* Return nonzero if two operands (typically of the same tree node)
2985 are necessarily equal. If either argument has side-effects this
2986 function returns zero. FLAGS modifies behavior as follows:
2988 If OEP_ONLY_CONST is set, only return nonzero for constants.
2989 This function tests whether the operands are indistinguishable;
2990 it does not test whether they are equal using C's == operation.
2991 The distinction is important for IEEE floating point, because
2992 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2993 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2995 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2996 even though it may hold multiple values during a function.
2997 This is because a GCC tree node guarantees that nothing else is
2998 executed between the evaluation of its "operands" (which may often
2999 be evaluated in arbitrary order). Hence if the operands themselves
3000 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3001 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3002 unset means assuming isochronic (or instantaneous) tree equivalence.
3003 Unless comparing arbitrary expression trees, such as from different
3004 statements, this flag can usually be left unset.
3006 If OEP_PURE_SAME is set, then pure functions with identical arguments
3007 are considered the same. It is used when the caller has other ways
3008 to ensure that global memory is unchanged in between. */
3010 int
3012 {
3013 /* If either is ERROR_MARK, they aren't equal. */
3017 /* Check equality of integer constants before bailing out due to
3018 precision differences. */
3022 /* If both types don't have the same signedness, then we can't consider
3023 them equal. We must check this before the STRIP_NOPS calls
3024 because they may change the signedness of the arguments. As pointers
3025 strictly don't have a signedness, require either two pointers or
3026 two non-pointers as well. */
3031 /* If both types don't have the same precision, then it is not safe
3032 to strip NOPs. */
3039 /* In case both args are comparisons but with different comparison
3040 code, try to swap the comparison operands of one arg to produce
3041 a match and compare that variant. */
3045 {
3053 }
3056 /* This is needed for conversions and for COMPONENT_REF.
3057 Might as well play it safe and always test this. */
3063 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3064 We don't care about side effects in that case because the SAVE_EXPR
3065 takes care of that for us. In all other cases, two expressions are
3066 equal if they have no side effects. If we have two identical
3067 expressions with side effects that should be treated the same due
3068 to the only side effects being identical SAVE_EXPR's, that will
3069 be detected in the recursive calls below. */
3075 /* Next handle constant cases, those for which we can return 1 even
3076 if ONLY_CONST is set. */
3079 {
3094 {
3095 /* If we do not distinguish between signed and unsigned zero,
3096 consider them equal. */
3099 }
3103 {
3109 {
3111 flags))
3115 }
3118 }
3122 flags)
3124 flags));
3137 }
3142 /* Define macros to test an operand from arg0 and arg1 for equality and a
3143 variant that allows null and views null as being different from any
3144 non-null value. In the latter case, if either is null, the both
3145 must be; otherwise, do the normal comparison. */
3146 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3147 TREE_OPERAND (arg1, N), flags)
3149 #define OP_SAME_WITH_NULL(N) \
3150 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3151 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3154 {
3156 /* Two conversions are equal only if signedness and modes match. */
3158 {
3159 CASE_CONVERT:
3167 }
3177 /* For commutative ops, allow the other order. */
3185 /* If either of the pointer (or reference) expressions we are
3186 dereferencing contain a side effect, these cannot be equal. */
3192 {
3202 /* Operands 2 and 3 may be null.
3203 Compare the array index by value if it is constant first as we
3204 may have different types but same value here. */
3213 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3214 may be NULL when we're called to compare MEM_EXPRs. */
3224 }
3228 {
3243 /* Otherwise take into account this is a commutative operation. */
3254 }
3258 {
3260 /* If the CALL_EXPRs call different functions, then they
3261 clearly can not be equal. */
3263 flags))
3266 {
3270 else
3274 }
3276 /* Now see if all the arguments are the same. */
3277 {
3288 /* If we get here and both argument lists are exhausted
3289 then the CALL_EXPRs are equal. */
3291 }
3294 }
3297 /* Consider __builtin_sqrt equal to sqrt. */
3305 }
3307 #undef OP_SAME
3308 #undef OP_SAME_WITH_NULL
3309 }
3310 \f
3311 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3312 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3314 When in doubt, return 0. */
3316 static int
3318 {
3330 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3331 and see if the inner values are the same. This removes any
3332 signedness comparison, which doesn't matter here. */
3339 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3340 actual comparison operand, ARG0.
3342 First throw away any conversions to wider types
3343 already present in the operands. */
3352 {
3355 /* Make sure shorter operand is extended the right way
3356 to match the longer operand. */
3362 }
3365 }
3366 \f
3367 /* See if ARG is an expression that is either a comparison or is performing
3368 arithmetic on comparisons. The comparisons must only be comparing
3369 two different values, which will be stored in *CVAL1 and *CVAL2; if
3370 they are nonzero it means that some operands have already been found.
3371 No variables may be used anywhere else in the expression except in the
3372 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3373 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3375 If this is true, return 1. Otherwise, return zero. */
3377 static int
3379 {
3383 /* We can handle some of the tcc_expression cases here. */
3393 {
3394 /* If we've already found a CVAL1 or CVAL2, this expression is
3395 two complex to handle. */
3401 }
3404 {
3427 /* First see if we can handle the first operand, then the second. For
3428 the second operand, we know *CVAL1 can't be zero. It must be that
3429 one side of the comparison is each of the values; test for the
3430 case where this isn't true by failing if the two operands
3431 are the same. */
3440 ;
3444 ;
3445 else
3449 ;
3453 ;
3454 else
3461 }
3462 }
3463 \f
3464 /* ARG is a tree that is known to contain just arithmetic operations and
3465 comparisons. Evaluate the operations in the tree substituting NEW0 for
3466 any occurrence of OLD0 as an operand of a comparison and likewise for
3467 NEW1 and OLD1. */
3469 static tree
3471 {
3476 /* We can handle some of the tcc_expression cases here. */
3484 {
3499 {
3516 }
3517 /* Fall through - ??? */
3520 {
3524 /* We need to check both for exact equality and tree equality. The
3525 former will be true if the operand has a side-effect. In that
3526 case, we know the operand occurred exactly once. */
3539 }
3543 }
3544 }
3545 \f
3546 /* Return a tree for the case when the result of an expression is RESULT
3547 converted to TYPE and OMITTED was previously an operand of the expression
3548 but is now not needed (e.g., we folded OMITTED * 0).
3550 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3551 the conversion of RESULT to TYPE. */
3553 tree
3555 {
3558 /* If the resulting operand is an empty statement, just return the omitted
3559 statement casted to void. */
3567 }
3569 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3571 static tree
3573 {
3576 /* If the resulting operand is an empty statement, just return the omitted
3577 statement casted to void. */
3585 }
3587 /* Return a tree for the case when the result of an expression is RESULT
3588 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3589 of the expression but are now not needed.
3591 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3592 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3593 evaluated before OMITTED2. Otherwise, if neither has side effects,
3594 just do the conversion of RESULT to TYPE. */
3596 tree
3598 {
3607 }
3609 \f
3610 /* Return a simplified tree node for the truth-negation of ARG. This
3611 never alters ARG itself. We assume that ARG is an operation that
3612 returns a truth value (0 or 1).
3614 FIXME: one would think we would fold the result, but it causes
3615 problems with the dominator optimizer. */
3617 tree
3619 {
3623 /* If this is a comparison, we can simply invert it, except for
3624 floating-point non-equality comparisons, in which case we just
3625 enclose a TRUTH_NOT_EXPR around what we have. */
3628 {
3631 && flag_trapping_math
3635 else
3636 {
3641 else
3644 }
3645 }
3648 {
3663 /* Here we can invert either operand. We invert the first operand
3664 unless the second operand is a TRUTH_NOT_EXPR in which case our
3665 result is the XOR of the first operand with the inside of the
3666 negation of the second operand. */
3671 else
3690 {
3693 /* A COND_EXPR may have a throw as one operand, which
3694 then has void type. Just leave void operands
3695 as they are. */
3701 }
3734 }
3737 }
3739 /* Return a simplified tree node for the truth-negation of ARG. This
3740 never alters ARG itself. We assume that ARG is an operation that
3741 returns a truth value (0 or 1).
3743 FIXME: one would think we would fold the result, but it causes
3744 problems with the dominator optimizer. */
3746 tree
3748 {
3749 tree tem;
3759 }
3761 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3762 operands are another bit-wise operation with a common input. If so,
3763 distribute the bit operations to save an operation and possibly two if
3764 constants are involved. For example, convert
3765 (A | B) & (A | C) into A | (B & C)
3766 Further simplification will occur if B and C are constants.
3768 If this optimization cannot be done, 0 will be returned. */
3770 static tree
3772 {
3773 tree common;
3783 {
3787 }
3789 {
3793 }
3795 {
3799 }
3801 {
3805 }
3806 else
3814 }
3816 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3817 with code CODE. This optimization is unsafe. */
3818 static tree
3820 {
3824 /* (A / C) +- (B / C) -> (A +- B) / C. */
3834 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3839 {
3851 }
3854 }
3855 \f
3856 /* Subroutine for fold_truthop: decode a field reference.
3858 If EXP is a comparison reference, we return the innermost reference.
3860 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3861 set to the starting bit number.
3863 If the innermost field can be completely contained in a mode-sized
3864 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3866 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3867 otherwise it is not changed.
3869 *PUNSIGNEDP is set to the signedness of the field.
3871 *PMASK is set to the mask used. This is either contained in a
3872 BIT_AND_EXPR or derived from the width of the field.
3874 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3876 Return 0 if this is not a component reference or is one that we can't
3877 do anything with. */
3879 static tree
3884 {
3888 tree unsigned_type;
3891 /* All the optimizations using this function assume integer fields.
3892 There are problems with FP fields since the type_for_size call
3893 below can fail for, e.g., XFmode. */
3897 /* We are interested in the bare arrangement of bits, so strip everything
3898 that doesn't affect the machine mode. However, record the type of the
3899 outermost expression if it may matter below. */
3906 {
3912 }
3921 /* If the number of bits in the reference is the same as the bitsize of
3922 the outer type, then the outer type gives the signedness. Otherwise
3923 (in case of a small bitfield) the signedness is unchanged. */
3927 /* Compute the mask to access the bitfield. */
3936 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3944 }
3946 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3947 represents the sign bit of EXP's type. If EXP represents a sign
3948 or zero extension, also test VAL against the unextended type.
3949 The return value is the (sub)expression whose sign bit is VAL,
3950 or NULL_TREE otherwise. */
3952 static tree
3954 {
3958 tree t;
3960 /* Tree EXP must have an integral type. */
3965 /* Tree VAL must be an integer constant. */
3972 {
3979 }
3980 else
3981 {
3988 }
3990 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
3991 treat VAL as if it were unsigned. */
3996 /* Handle extension from a narrower type. */
4002 }
4004 /* Subroutine for fold_truthop: determine if an operand is simple enough
4005 to be evaluated unconditionally. */
4007 static int
4009 {
4010 /* Strip any conversions that don't change the machine mode. */
4019 /* Don't regard global variables as simple. They may be
4020 allocated in ways unknown to the compiler (shared memory,
4021 #pragma weak, etc). */
4024 /* Loading a static variable is unduly expensive, but global
4025 registers aren't expensive. */
4027 }
4028 \f
4029 /* The following functions are subroutines to fold_range_test and allow it to
4030 try to change a logical combination of comparisons into a range test.
4032 For example, both
4033 X == 2 || X == 3 || X == 4 || X == 5
4034 and
4035 X >= 2 && X <= 5
4036 are converted to
4037 (unsigned) (X - 2) <= 3
4039 We describe each set of comparisons as being either inside or outside
4040 a range, using a variable named like IN_P, and then describe the
4041 range with a lower and upper bound. If one of the bounds is omitted,
4042 it represents either the highest or lowest value of the type.
4044 In the comments below, we represent a range by two numbers in brackets
4045 preceded by a "+" to designate being inside that range, or a "-" to
4046 designate being outside that range, so the condition can be inverted by
4047 flipping the prefix. An omitted bound is represented by a "-". For
4048 example, "- [-, 10]" means being outside the range starting at the lowest
4049 possible value and ending at 10, in other words, being greater than 10.
4050 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4051 always false.
4053 We set up things so that the missing bounds are handled in a consistent
4054 manner so neither a missing bound nor "true" and "false" need to be
4055 handled using a special case. */
4057 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4058 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4059 and UPPER1_P are nonzero if the respective argument is an upper bound
4060 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4061 must be specified for a comparison. ARG1 will be converted to ARG0's
4062 type if both are specified. */
4064 static tree
4067 {
4068 tree tem;
4072 /* If neither arg represents infinity, do the normal operation.
4073 Else, if not a comparison, return infinity. Else handle the special
4074 comparison rules. Note that most of the cases below won't occur, but
4075 are handled for consistency. */
4078 {
4083 }
4088 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4089 for neither. In real maths, we cannot assume open ended ranges are
4090 the same. But, this is computer arithmetic, where numbers are finite.
4091 We can therefore make the transformation of any unbounded range with
4092 the value Z, Z being greater than any representable number. This permits
4093 us to treat unbounded ranges as equal. */
4097 {
4118 }
4121 }
4122 \f
4123 /* Given EXP, a logical expression, set the range it is testing into
4124 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4125 actually being tested. *PLOW and *PHIGH will be made of the same
4126 type as the returned expression. If EXP is not a comparison, we
4127 will most likely not be returning a useful value and range. Set
4128 *STRICT_OVERFLOW_P to true if the return value is only valid
4129 because signed overflow is undefined; otherwise, do not change
4130 *STRICT_OVERFLOW_P. */
4132 static tree
4135 {
4142 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4143 and see if we can refine the range. Some of the cases below may not
4144 happen, but it doesn't seem worth worrying about this. We "continue"
4145 the outer loop when we've changed something; otherwise we "break"
4146 the switch, which will "break" the while. */
4152 {
4157 {
4169 }
4172 {
4179 /* We can only do something if the range is testing for zero
4180 and if the second operand is an integer constant. Note that
4181 saying something is "in" the range we make is done by
4182 complementing IN_P since it will set in the initial case of
4183 being not equal to zero; "out" is leaving it alone. */
4190 {
4211 }
4213 /* If this is an unsigned comparison, we also know that EXP is
4214 greater than or equal to zero. We base the range tests we make
4215 on that fact, so we record it here so we can parse existing
4216 range tests. We test arg0_type since often the return type
4217 of, e.g. EQ_EXPR, is boolean. */
4219 {
4223 NULL_TREE))
4228 /* If the high bound is missing, but we have a nonzero low
4229 bound, reverse the range so it goes from zero to the low bound
4230 minus 1. */
4232 {
4237 }
4238 }
4244 /* (-x) IN [a,b] -> x in [-b, -a] */
4256 /* ~ X -> -X - 1 */
4265 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4266 move a constant to the other side. */
4271 /* If EXP is signed, any overflow in the computation is undefined,
4272 so we don't worry about it so long as our computations on
4273 the bounds don't overflow. For unsigned, overflow is defined
4274 and this is exactly the right thing. */
4286 /* Check for an unsigned range which has wrapped around the maximum
4287 value thus making n_high < n_low, and normalize it. */
4289 {
4295 /* If the range is of the form +/- [ x+1, x ], we won't
4296 be able to normalize it. But then, it represents the
4297 whole range or the empty set, so make it
4298 +/- [ -, - ]. */
4302 else
4304 }
4305 else
4329 /* If we're converting arg0 from an unsigned type, to exp,
4330 a signed type, we will be doing the comparison as unsigned.
4331 The tests above have already verified that LOW and HIGH
4332 are both positive.
4334 So we have to ensure that we will handle large unsigned
4335 values the same way that the current signed bounds treat
4336 negative values. */
4339 {
4340 tree high_positive;
4341 tree equiv_type;
4342 /* For fixed-point modes, we need to pass the saturating flag
4343 as the 2nd parameter. */
4348 else
4352 /* A range without an upper bound is, naturally, unbounded.
4353 Since convert would have cropped a very large value, use
4354 the max value for the destination type. */
4355 high_positive
4362 high_positive),
4365 /* If the low bound is specified, "and" the range with the
4366 range for which the original unsigned value will be
4367 positive. */
4369 {
4373 integer_zero_node),
4374 high_positive))
4378 }
4379 else
4380 {
4381 /* Otherwise, "or" the range with the range of the input
4382 that will be interpreted as negative. */
4386 integer_zero_node),
4387 high_positive))
4391 }
4392 }
4400 }
4403 }
4405 /* If EXP is a constant, we can evaluate whether this is true or false. */
4407 {
4414 }
4418 }
4419 \f
4420 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4421 type, TYPE, return an expression to test if EXP is in (or out of, depending
4422 on IN_P) the range. Return 0 if the test couldn't be created. */
4424 static tree
4426 {
4428 tree value;
4430 #ifdef HAVE_canonicalize_funcptr_for_compare
4431 /* Disable this optimization for function pointer expressions
4432 on targets that require function pointer canonicalization. */
4437 #endif
4440 {
4446 }
4464 {
4466 {
4470 }
4472 }
4474 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4476 {
4478 HOST_WIDE_INT hi;
4483 {
4486 }
4487 else
4488 {
4491 }
4494 {
4496 {
4499 etype
4501 else
4504 }
4507 }
4508 }
4510 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4511 This requires wrap-around arithmetics for the type of the expression. */
4513 {
4515 /* There is no requirement that LOW be within the range of ETYPE
4516 if the latter is a subtype. It must, however, be within the base
4517 type of ETYPE. So be sure we do the subtraction in that type. */
4530 }
4532 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4535 {
4538 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4539 for the type in question, as we rely on this here. */
4549 else
4551 }
4561 {
4563 {
4569 }
4571 }
4579 }
4580 \f
4581 /* Return the predecessor of VAL in its type, handling the infinite case. */
4583 static tree
4585 {
4591 else
4593 }
4595 /* Return the successor of VAL in its type, handling the infinite case. */
4597 static tree
4599 {
4605 else
4607 }
4609 /* Given two ranges, see if we can merge them into one. Return 1 if we
4610 can, 0 if we can't. Set the output range into the specified parameters. */
4612 static int
4615 {
4619 tree tem;
4629 /* Make range 0 be the range that starts first, or ends last if they
4630 start at the same value. Swap them if it isn't. */
4633 || (lowequal
4636 {
4640 }
4642 /* Now flag two cases, whether the ranges are disjoint or whether the
4643 second range is totally subsumed in the first. Note that the tests
4644 below are simplified by the ones above. */
4650 /* We now have four cases, depending on whether we are including or
4651 excluding the two ranges. */
4653 {
4654 /* If they don't overlap, the result is false. If the second range
4655 is a subset it is the result. Otherwise, the range is from the start
4656 of the second to the end of the first. */
4661 else
4663 }
4666 {
4667 /* If they don't overlap, the result is the first range. If they are
4668 equal, the result is false. If the second range is a subset of the
4669 first, and the ranges begin at the same place, we go from just after
4670 the end of the second range to the end of the first. If the second
4671 range is not a subset of the first, or if it is a subset and both
4672 ranges end at the same place, the range starts at the start of the
4673 first range and ends just before the second range.
4674 Otherwise, we can't describe this as a single range. */
4680 {
4685 {
4686 /* We are in the weird situation where high0 > high1 but
4687 high1 has no successor. Punt. */
4689 }
4690 }
4692 {
4697 {
4698 /* low0 < low1 but low1 has no predecessor. Punt. */
4700 }
4701 }
4702 else
4704 }
4707 {
4708 /* If they don't overlap, the result is the second range. If the second
4709 is a subset of the first, the result is false. Otherwise,
4710 the range starts just after the first range and ends at the
4711 end of the second. */
4716 else
4717 {
4722 {
4723 /* high1 > high0 but high0 has no successor. Punt. */
4725 }
4726 }
4727 }
4729 else
4730 {
4731 /* The case where we are excluding both ranges. Here the complex case
4732 is if they don't overlap. In that case, the only time we have a
4733 range is if they are adjacent. If the second is a subset of the
4734 first, the result is the first. Otherwise, the range to exclude
4735 starts at the beginning of the first range and ends at the end of the
4736 second. */
4738 {
4743 else
4744 {
4745 /* Canonicalize - [min, x] into - [-, x]. */
4748 {
4753 /* FALLTHROUGH */
4766 }
4768 /* Canonicalize - [x, max] into - [x, -]. */
4771 {
4776 /* FALLTHROUGH */
4791 }
4793 /* The ranges might be also adjacent between the maximum and
4794 minimum values of the given type. For
4795 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4796 return + [x + 1, y - 1]. */
4798 {
4805 }
4806 else
4808 }
4809 }
4812 else
4814 }
4818 }
4819 \f
4821 /* Subroutine of fold, looking inside expressions of the form
4822 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4823 of the COND_EXPR. This function is being used also to optimize
4824 A op B ? C : A, by reversing the comparison first.
4826 Return a folded expression whose code is not a COND_EXPR
4827 anymore, or NULL_TREE if no folding opportunity is found. */
4829 static tree
4831 {
4836 tree tem;
4841 /* If we have A op 0 ? A : -A, consider applying the following
4842 transformations:
4844 A == 0? A : -A same as -A
4845 A != 0? A : -A same as A
4846 A >= 0? A : -A same as abs (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)
4851 None of these transformations work for modes with signed
4852 zeros. If A is +/-0, the first two transformations will
4853 change the sign of the result (from +0 to -0, or vice
4854 versa). The last four will fix the sign of the result,
4855 even though the original expressions could be positive or
4856 negative, depending on the sign of A.
4858 Note that all these transformations are correct if A is
4859 NaN, since the two alternatives (A and -A) are also NaNs. */
4866 /* In the case that A is of the form X-Y, '-A' (arg2) may
4867 have already been folded to Y-X, check for that. */
4875 {
4887 /* Fall through. */
4909 }
4911 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4912 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4913 both transformations are correct when A is NaN: A != 0
4914 is then true, and A == 0 is false. */
4918 {
4923 }
4925 /* Try some transformations of A op B ? A : B.
4927 A == B? A : B same as B
4928 A != B? A : B same as A
4929 A >= B? A : B same as max (A, B)
4930 A > B? A : B same as max (B, A)
4931 A <= B? A : B same as min (A, B)
4932 A < B? A : B same as min (B, A)
4934 As above, these transformations don't work in the presence
4935 of signed zeros. For example, if A and B are zeros of
4936 opposite sign, the first two transformations will change
4937 the sign of the result. In the last four, the original
4938 expressions give different results for (A=+0, B=-0) and
4939 (A=-0, B=+0), but the transformed expressions do not.
4941 The first two transformations are correct if either A or B
4942 is a NaN. In the first transformation, the condition will
4943 be false, and B will indeed be chosen. In the case of the
4944 second transformation, the condition A != B will be true,
4945 and A will be chosen.
4947 The conversions to max() and min() are not correct if B is
4948 a number and A is not. The conditions in the original
4949 expressions will be false, so all four give B. The min()
4950 and max() versions would give a NaN instead. */
4953 /* Avoid these transformations if the COND_EXPR may be used
4954 as an lvalue in the C++ front-end. PR c++/19199. */
4955 && (in_gimple_form
4960 {
4965 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4967 {
4971 }
4974 {
4983 /* In C++ a ?: expression can be an lvalue, so put the
4984 operand which will be used if they are equal first
4985 so that we can convert this back to the
4986 corresponding COND_EXPR. */
4988 {
4995 }
5002 {
5009 }
5022 }
5023 }
5025 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5026 we might still be able to simplify this. For example,
5027 if C1 is one less or one more than C2, this might have started
5028 out as a MIN or MAX and been transformed by this function.
5029 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5035 {
5037 /* We can replace A with C1 in this case. */
5042 /* If C1 is C2 + 1, this is min(A, C2). */
5044 OEP_ONLY_CONST)
5048 OEP_ONLY_CONST))
5050 type,
5052 arg2));
5056 /* If C1 is C2 - 1, this is min(A, C2). */
5058 OEP_ONLY_CONST)
5062 OEP_ONLY_CONST))
5064 type,
5066 arg2));
5070 /* If C1 is C2 - 1, this is max(A, C2). */
5072 OEP_ONLY_CONST)
5076 OEP_ONLY_CONST))
5078 type,
5080 arg2));
5084 /* If C1 is C2 + 1, this is max(A, C2). */
5086 OEP_ONLY_CONST)
5090 OEP_ONLY_CONST))
5092 type,
5094 arg2));
5100 }
5103 }
5106 \f
5107 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5108 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5109 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5110 false) >= 2)
5111 #endif
5113 /* EXP is some logical combination of boolean tests. See if we can
5114 merge it into some range test. Return the new tree if so. */
5116 static tree
5118 {
5126 tree tem;
5130 /* If this is an OR operation, invert both sides; we will invert
5131 again at the end. */
5135 /* If both expressions are the same, if we can merge the ranges, and we
5136 can build the range test, return it or it inverted. If one of the
5137 ranges is always true or always false, consider it to be the same
5138 expression as the other. */
5146 {
5150 }
5152 /* On machines where the branch cost is expensive, if this is a
5153 short-circuited branch and the underlying object on both sides
5154 is the same, make a non-short-circuit operation. */
5160 {
5161 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5162 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5163 which cases we can't do this. */
5171 {
5180 {
5183 WARN_STRICT_OVERFLOW_COMPARISON);
5187 }
5188 }
5189 }
5192 }
5193 \f
5194 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5195 bit value. Arrange things so the extra bits will be set to zero if and
5196 only if C is signed-extended to its full width. If MASK is nonzero,
5197 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5199 static tree
5201 {
5204 tree temp;
5209 /* We work by getting just the sign bit into the low-order bit, then
5210 into the high-order bit, then sign-extend. We then XOR that value
5211 with C. */
5215 /* We must use a signed type in order to get an arithmetic right shift.
5216 However, we must also avoid introducing accidental overflows, so that
5217 a subsequent call to integer_zerop will work. Hence we must
5218 do the type conversion here. At this point, the constant is either
5219 zero or one, and the conversion to a signed type can never overflow.
5220 We could get an overflow if this conversion is done anywhere else. */
5229 /* If necessary, convert the type back to match the type of C. */
5234 }
5235 \f
5236 /* Find ways of folding logical expressions of LHS and RHS:
5237 Try to merge two comparisons to the same innermost item.
5238 Look for range tests like "ch >= '0' && ch <= '9'".
5239 Look for combinations of simple terms on machines with expensive branches
5240 and evaluate the RHS unconditionally.
5242 For example, if we have p->a == 2 && p->b == 4 and we can make an
5243 object large enough to span both A and B, we can do this with a comparison
5244 against the object ANDed with the a mask.
5246 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5247 operations to do this with one comparison.
5249 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5250 function and the one above.
5252 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5253 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5255 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5256 two operands.
5258 We return the simplified tree or 0 if no optimization is possible. */
5260 static tree
5262 {
5263 /* If this is the "or" of two comparisons, we can do something if
5264 the comparisons are NE_EXPR. If this is the "and", we can do something
5265 if the comparisons are EQ_EXPR. I.e.,
5266 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5268 WANTED_CODE is this operation code. For single bit fields, we can
5269 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5270 comparison for one-bit fields. */
5292 /* Start by getting the comparison codes. Fail if anything is volatile.
5293 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5294 it were surrounded with a NE_EXPR. */
5303 {
5307 }
5310 {
5314 }
5325 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5328 {
5329 tree result;
5332 {
5337 }
5340 {
5346 }
5347 }
5352 /* If the RHS can be evaluated unconditionally and its operands are
5353 simple, it wins to evaluate the RHS unconditionally on machines
5354 with expensive branches. In this case, this isn't a comparison
5355 that can be merged. Avoid doing this if the RHS is a floating-point
5356 comparison since those can trap. */
5363 {
5364 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5375 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5387 {
5391 }
5392 }
5394 /* See if the comparisons can be merged. Then get all the parameters for
5395 each side. */
5419 /* It must be true that the inner operation on the lhs of each
5420 comparison must be the same if we are to be able to do anything.
5421 Then see if we have constants. If not, the same must be true for
5422 the rhs's. */
5433 else
5436 /* If either comparison code is not correct for our logical operation,
5437 fail. However, we can convert a one-bit comparison against zero into
5438 the opposite comparison against that bit being set in the field. */
5442 {
5444 {
5445 /* Make the left operand unsigned, since we are only interested
5446 in the value of one bit. Otherwise we are doing the wrong
5447 thing below. */
5450 }
5451 else
5453 }
5455 /* This is analogous to the code for l_const above. */
5457 {
5459 {
5462 }
5463 else
5465 }
5467 /* See if we can find a mode that contains both fields being compared on
5468 the left. If we can't, fail. Otherwise, update all constants and masks
5469 to be relative to a field of that size. */
5474 volatilep);
5484 {
5487 }
5495 {
5503 {
5507 }
5508 }
5510 {
5518 {
5522 }
5523 }
5525 /* Handle the case of comparisons with constants. If there is something in
5526 common between the masks, those bits of the constants must be the same.
5527 If not, the condition is always false. Test for this to avoid generating
5528 incorrect code below. */
5533 {
5535 {
5538 }
5539 else
5540 {
5543 }
5544 }
5547 }
5548 \f
5549 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5550 constant. */
5552 static tree
5554 {
5557 tree comp_const;
5558 tree minmax_const;
5560 tree inner;
5571 /* If something does not permit us to optimize, return the original tree. */
5579 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5580 and GT_EXPR, doing the rest with recursive calls using logical
5581 simplifications. */
5583 {
5585 {
5591 }
5594 return
5596 optimize_minmax_comparison
5598 optimize_minmax_comparison
5603 /* MAX (X, 0) == 0 -> X <= 0 */
5607 /* MAX (X, 0) == 5 -> X == 5 */
5611 /* MAX (X, 0) == -1 -> false */
5615 /* MIN (X, 0) == 0 -> X >= 0 */
5619 /* MIN (X, 0) == 5 -> false */
5622 else
5623 /* MIN (X, 0) == -1 -> X == -1 */
5628 /* MAX (X, 0) > 0 -> X > 0
5629 MAX (X, 0) > 5 -> X > 5 */
5633 /* MAX (X, 0) > -1 -> true */
5637 /* MIN (X, 0) > 0 -> false
5638 MIN (X, 0) > 5 -> false */
5641 else
5642 /* MIN (X, 0) > -1 -> X > -1 */
5647 }
5648 }
5649 \f
5650 /* T is an integer expression that is being multiplied, divided, or taken a
5651 modulus (CODE says which and what kind of divide or modulus) by a
5652 constant C. See if we can eliminate that operation by folding it with
5653 other operations already in T. WIDE_TYPE, if non-null, is a type that
5654 should be used for the computation if wider than our type.
5656 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5657 (X * 2) + (Y * 4). We must, however, be assured that either the original
5658 expression would not overflow or that overflow is undefined for the type
5659 in the language in question.
5661 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5662 the machine has a multiply-accumulate insn or that this is part of an
5663 addressing calculation.
5665 If we return a non-null expression, it is an equivalent form of the
5666 original computation, but need not be in the original type.
5668 We set *STRICT_OVERFLOW_P to true if the return values depends on
5669 signed overflow being undefined. Otherwise we do not change
5670 *STRICT_OVERFLOW_P. */
5672 static tree
5675 {
5676 /* To avoid exponential search depth, refuse to allow recursion past
5677 three levels. Beyond that (1) it's highly unlikely that we'll find
5678 something interesting and (2) we've probably processed it before
5679 when we built the inner expression. */
5682 tree ret;
5687 depth++;
5689 depth--;
5692 }
5694 static tree
5697 {
5708 /* Don't deal with constants of zero here; they confuse the code below. */
5718 /* Note that we need not handle conditional operations here since fold
5719 already handles those cases. So just do arithmetic here. */
5721 {
5723 /* For a constant, we can always simplify if we are a multiply
5724 or (for divide and modulus) if it is a multiple of our constant. */
5732 /* If op0 is an expression ... */
5738 /* ... and has wrapping overflow, and its type is smaller
5739 than ctype, then we cannot pass through as widening. */
5745 /* ... or this is a truncation (t is narrower than op0),
5746 then we cannot pass through this narrowing. */
5749 /* ... or signedness changes for division or modulus,
5750 then we cannot pass through this conversion. */
5754 /* ... or has undefined overflow while the converted to
5755 type has not, we cannot do the operation in the inner type
5756 as that would introduce undefined overflow. */
5761 /* Pass the constant down and see if we can make a simplification. If
5762 we can, replace this expression with the inner simplification for
5763 possible later conversion to our or some other type. */
5768 code == MULT_EXPR
5770 strict_overflow_p))))
5775 /* If widening the type changes it from signed to unsigned, then we
5776 must avoid building ABS_EXPR itself as unsigned. */
5778 {
5782 {
5785 }
5787 }
5788 /* If the constant is negative, we cannot simplify this. */
5791 /* FALLTHROUGH */
5799 /* If widening the type changes the signedness, then we can't perform
5800 this optimization as that changes the result. */
5804 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5810 {
5817 }
5821 /* If the second operand is constant, this is a multiplication
5822 or floor division, by a power of two, so we can treat it that
5823 way unless the multiplier or divisor overflows. Signed
5824 left-shift overflow is implementation-defined rather than
5825 undefined in C90, so do not convert signed left shift into
5826 multiplication. */
5829 /* const_binop may not detect overflow correctly,
5830 so check for it explicitly here. */
5835 size_one_node,
5845 /* See if we can eliminate the operation on both sides. If we can, we
5846 can return a new PLUS or MINUS. If we can't, the only remaining
5847 cases where we can do anything are if the second operand is a
5848 constant. */
5854 /* If not multiplication, we can only do this if both operands
5855 are divisible by c. */
5858 {
5863 }
5865 /* If this was a subtraction, negate OP1 and set it to be an addition.
5866 This simplifies the logic below. */
5873 /* If either OP1 or C are negative, this optimization is not safe for
5874 some of the division and remainder types while for others we need
5875 to change the code. */
5877 {
5885 }
5887 /* If it's a multiply or a division/modulus operation of a multiple
5888 of our constant, do the operation and verify it doesn't overflow. */
5891 {
5894 /* We allow the constant to overflow with wrapping semantics. */
5898 }
5899 else
5902 /* If we have an unsigned type is not a sizetype, we cannot widen
5903 the operation since it will change the result if the original
5904 computation overflowed. */
5910 /* If we were able to eliminate our operation from the first side,
5911 apply our operation to the second side and reform the PLUS. */
5915 /* The last case is if we are a multiply. In that case, we can
5916 apply the distributive law to commute the multiply and addition
5917 if the multiplication of the constants doesn't overflow. */
5923 op1);
5928 /* We have a special case here if we are doing something like
5929 (C * 8) % 4 since we know that's zero. */
5932 /* If the multiplication can overflow we cannot optimize this.
5933 ??? Until we can properly mark individual operations as
5934 not overflowing we need to treat sizetype special here as
5935 stor-layout relies on this opimization to make
5936 DECL_FIELD_BIT_OFFSET always a constant. */
5942 {
5945 }
5947 /* ... fall through ... */
5951 /* If we can extract our operation from the LHS, do so and return a
5952 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5953 do something only if the second operand is a constant. */
5967 /* If these are the same operation types, we can associate them
5968 assuming no overflow. */
5980 /* If these operations "cancel" each other, we have the main
5981 optimizations of this pass, which occur when either constant is a
5982 multiple of the other, in which case we replace this with either an
5983 operation or CODE or TCODE.
5985 If we have an unsigned type that is not a sizetype, we cannot do
5986 this since it will change the result if the original computation
5987 overflowed. */
5995 {
5997 {
6004 }
6006 {
6013 }
6014 }
6019 }
6022 }
6023 \f
6024 /* Return a node which has the indicated constant VALUE (either 0 or
6025 1), and is of the indicated TYPE. */
6027 tree
6029 {
6034 else
6036 }
6039 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6040 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6041 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6042 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6043 COND is the first argument to CODE; otherwise (as in the example
6044 given here), it is the second argument. TYPE is the type of the
6045 original expression. Return NULL_TREE if no simplification is
6046 possible. */
6048 static tree
6052 {
6059 /* This transformation is only worthwhile if we don't have to wrap
6060 arg in a SAVE_EXPR, and the operation can be simplified on at least
6061 one of the branches once its pushed inside the COND_EXPR. */
6066 {
6070 /* If this operand throws an expression, then it does not make
6071 sense to try to perform a logical or arithmetic operation
6072 involving it. */
6077 }
6078 else
6079 {
6084 }
6088 {
6092 else
6094 }
6096 {
6100 else
6102 }
6106 }
6108 \f
6109 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6111 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6112 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6113 ADDEND is the same as X.
6115 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6116 and finite. The problematic cases are when X is zero, and its mode
6117 has signed zeros. In the case of rounding towards -infinity,
6118 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6119 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6121 bool
6123 {
6127 /* Don't allow the fold with -fsignaling-nans. */
6131 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6135 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6140 /* The mode has signed zeros, and we have to honor their sign.
6141 In this situation, there is only one case we can return true for.
6142 X - 0 is the same as X unless rounding towards -infinity is
6143 supported. */
6145 }
6147 /* Subroutine of fold() that checks comparisons of built-in math
6148 functions against real constants.
6150 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6151 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6152 is the type of the result and ARG0 and ARG1 are the operands of the
6153 comparison. ARG1 must be a TREE_REAL_CST.
6155 The function returns the constant folded tree if a simplification
6156 can be made, and NULL_TREE otherwise. */
6158 static tree
6161 {
6162 REAL_VALUE_TYPE c;
6165 {
6171 {
6172 /* sqrt(x) < y is always false, if y is negative. */
6176 /* sqrt(x) > y is always true, if y is negative and we
6177 don't care about NaNs, i.e. negative values of x. */
6181 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6184 }
6186 {
6187 REAL_VALUE_TYPE c2;
6193 {
6194 /* sqrt(x) > y is x == +Inf, when y is very large. */
6199 /* sqrt(x) > y is always false, when y is very large
6200 and we don't care about infinities. */
6202 }
6204 /* sqrt(x) > c is the same as x > c*c. */
6207 }
6209 {
6210 REAL_VALUE_TYPE c2;
6216 {
6217 /* sqrt(x) < y is always true, when y is a very large
6218 value and we don't care about NaNs or Infinities. */
6222 /* sqrt(x) < y is x != +Inf when y is very large and we
6223 don't care about NaNs. */
6228 /* sqrt(x) < y is x >= 0 when y is very large and we
6229 don't care about Infinities. */
6234 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6243 dconst0)),
6246 c2)));
6247 }
6249 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6254 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6257 {
6262 dconst0)),
6265 c2)));
6266 }
6267 }
6268 }
6271 }
6273 /* Subroutine of fold() that optimizes comparisons against Infinities,
6274 either +Inf or -Inf.
6276 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6277 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6278 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6280 The function returns the constant folded tree if a simplification
6281 can be made, and NULL_TREE otherwise. */
6283 static tree
6285 {
6287 REAL_VALUE_TYPE max;
6288 tree temp;
6293 /* For negative infinity swap the sense of the comparison. */
6299 {
6301 /* x > +Inf is always false, if with ignore sNANs. */
6307 /* x <= +Inf is always true, if we don't case about NaNs. */
6311 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6314 {
6317 }
6322 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6328 /* x < +Inf is always equal to x <= DBL_MAX. */
6334 /* x != +Inf is always equal to !(x > DBL_MAX). */
6346 }
6349 }
6351 /* Subroutine of fold() that optimizes comparisons of a division by
6352 a nonzero integer constant against an integer constant, i.e.
6353 X/C1 op C2.
6355 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6356 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6357 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6359 The function returns the constant folded tree if a simplification
6360 can be made, and NULL_TREE otherwise. */
6362 static tree
6364 {
6369 HOST_WIDE_INT hpart;
6374 /* We have to do this the hard way to detect unsigned overflow.
6375 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6386 {
6391 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6399 }
6401 {
6405 {
6424 }
6425 }
6426 else
6427 {
6428 /* A negative divisor reverses the relational operators. */
6434 {
6453 }
6454 }
6457 {
6478 {
6481 }
6486 {
6489 }
6494 {
6497 }
6502 {
6505 }
6510 }
6513 }
6516 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6517 equality/inequality test, then return a simplified form of the test
6518 using a sign testing. Otherwise return NULL. TYPE is the desired
6519 result type. */
6521 static tree
6523 tree result_type)
6524 {
6525 /* If this is testing a single bit, we can optimize the test. */
6529 {
6530 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6531 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6535 /* This is only a win if casting to a signed type is cheap,
6536 i.e. when arg00's type is not a partial mode. */
6539 {
6544 }
6545 }
6548 }
6550 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6551 equality/inequality test, then return a simplified form of
6552 the test using shifts and logical operations. Otherwise return
6553 NULL. TYPE is the desired result type. */
6555 tree
6557 tree result_type)
6558 {
6559 /* If this is testing a single bit, we can optimize the test. */
6563 {
6572 /* First, see if we can fold the single bit test into a sign-bit
6573 test. */
6575 result_type);
6579 /* Otherwise we have (A & C) != 0 where C is a single bit,
6580 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6581 Similarly for (A & C) == 0. */
6583 /* If INNER is a right shift of a constant and it plus BITNUM does
6584 not overflow, adjust BITNUM and INNER. */
6591 {
6594 }
6596 /* If we are going to be able to omit the AND below, we must do our
6597 operations as unsigned. If we must use the AND, we have a choice.
6598 Normally unsigned is faster, but for some machines signed is. */
6599 #ifdef LOAD_EXTEND_OP
6602 #else
6604 #endif
6620 /* Put the AND last so it can combine with more things. */
6623 /* Make sure to return the proper type. */
6627 }
6629 }
6631 /* Check whether we are allowed to reorder operands arg0 and arg1,
6632 such that the evaluation of arg1 occurs before arg0. */
6634 static bool
6636 {
6643 }
6645 /* Test whether it is preferable two swap two operands, ARG0 and
6646 ARG1, for example because ARG0 is an integer constant and ARG1
6647 isn't. If REORDER is true, only recommend swapping if we can
6648 evaluate the operands in reverse order. */
6650 bool
6652 {
6688 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6689 for commutative and comparison operators. Ensuring a canonical
6690 form allows the optimizers to find additional redundancies without
6691 having to explicitly check for both orderings. */
6697 /* Put SSA_NAMEs last. */
6703 /* Put variables last. */
6710 }
6712 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6713 ARG0 is extended to a wider type. */
6715 static tree
6717 {
6719 tree arg1_unw;
6728 #ifdef HAVE_canonicalize_funcptr_for_compare
6729 /* Disable this optimization if we're casting a function pointer
6730 type on targets that require function pointer canonicalization. */
6735 #endif
6742 /* If possible, express the comparison in the shorter mode. */
6762 /* If we are comparing with the integer that does not fit into the range
6763 of the shorter type, the result is known. */
6774 {
6801 }
6804 }
6806 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6807 ARG0 just the signedness is changed. */
6809 static tree
6812 {
6813 tree arg0_inner;
6823 #ifdef HAVE_canonicalize_funcptr_for_compare
6824 /* Disable this optimization if we're casting a function pointer
6825 type on targets that require function pointer canonicalization. */
6830 #endif
6835 /* If the conversion is from an integral subtype to its basetype
6836 leave it alone. */
6855 else
6859 }
6861 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6862 step of the array. Reconstructs s and delta in the case of s * delta
6863 being an integer constant (and thus already folded).
6864 ADDR is the address. MULT is the multiplicative expression.
6865 If the function succeeds, the new address expression is returned. Otherwise
6866 NULL_TREE is returned. */
6868 static tree
6870 {
6874 tree itype;
6877 /* Strip the nops that might be added when converting op1 to sizetype. */
6880 /* Canonicalize op1 into a possibly non-constant delta
6881 and an INTEGER_CST s. */
6883 {
6890 {
6893 }
6895 {
6898 }
6899 else
6901 }
6903 {
6906 }
6907 else
6908 {
6909 /* Simulate we are delta * 1. */
6912 }
6915 {
6917 {
6918 /* Remember if this was a multi-dimensional array. */
6931 {
6934 }
6935 else
6936 {
6937 /* Try if delta is a multiple of step. */
6942 }
6944 /* Only fold here if we can verify we do not overflow one
6945 dimension of a multi-dimensional array. */
6947 {
6948 tree tmp;
6964 }
6967 }
6968 else
6973 }
6975 /* We found the suitable array reference. So copy everything up to it,
6976 and replace the index. */
6983 {
6987 }
6995 }
6998 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6999 means A >= Y && A != MAX, but in this case we know that
7000 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7002 static tree
7004 {
7011 else
7020 {
7023 }
7025 {
7028 }
7029 else
7036 {
7037 /* Convert the pointer types into integer before taking the difference. */
7041 }
7042 else
7049 }
7051 /* Fold a sum or difference of at least one multiplication.
7052 Returns the folded tree or NULL if no simplification could be made. */
7054 static tree
7056 {
7060 /* (A * C) +- (B * C) -> (A+-B) * C.
7061 (A * C) +- A -> A * (C+-1).
7062 We are most concerned about the case where C is a constant,
7063 but other combinations show up during loop reduction. Since
7064 it is not difficult, try all four possibilities. */
7067 {
7070 }
7072 {
7075 }
7076 else
7077 {
7078 /* We cannot generate constant 1 for fract. */
7083 }
7085 {
7088 }
7090 {
7093 }
7094 else
7095 {
7096 /* We cannot generate constant 1 for fract. */
7101 }
7113 /* No identical multiplicands; see if we can find a common
7114 power-of-two factor in non-power-of-two multiplies. This
7115 can help in multi-dimensional array access. */
7118 {
7121 tree maybe_same;
7125 /* Move min of absolute values to int11. */
7128 {
7133 }
7134 else
7138 {
7146 }
7147 }
7157 }
7159 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7160 specified by EXPR into the buffer PTR of length LEN bytes.
7161 Return the number of bytes placed in the buffer, or zero
7162 upon failure. */
7164 static int
7166 {
7177 {
7181 else
7186 {
7193 else
7195 }
7196 else
7199 }
7201 }
7204 /* Subroutine of native_encode_expr. Encode the REAL_CST
7205 specified by EXPR into the buffer PTR of length LEN bytes.
7206 Return the number of bytes placed in the buffer, or zero
7207 upon failure. */
7209 static int
7211 {
7217 /* There are always 32 bits in each long, no matter the size of
7218 the hosts long. We handle floating point representations with
7219 up to 192 bits. */
7230 {
7235 {
7242 else
7244 }
7245 else
7248 }
7250 }
7252 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7253 specified by EXPR into the buffer PTR of length LEN bytes.
7254 Return the number of bytes placed in the buffer, or zero
7255 upon failure. */
7257 static int
7259 {
7261 tree part;
7272 }
7275 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7276 specified by EXPR into the buffer PTR of length LEN bytes.
7277 Return the number of bytes placed in the buffer, or zero
7278 upon failure. */
7280 static int
7282 {
7292 {
7294 {
7297 }
7298 else
7302 {
7305 }
7306 else
7307 {
7311 }
7313 }
7315 }
7318 /* Subroutine of native_encode_expr. Encode the STRING_CST
7319 specified by EXPR into the buffer PTR of length LEN bytes.
7320 Return the number of bytes placed in the buffer, or zero
7321 upon failure. */
7323 static int
7325 {
7327 HOST_WIDE_INT total_bytes;
7338 {
7342 }
7343 else
7346 }
7349 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7350 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7351 buffer PTR of length LEN bytes. Return the number of bytes
7352 placed in the buffer, or zero upon failure. */
7354 int
7356 {
7358 {
7376 }
7377 }
7380 /* Subroutine of native_interpret_expr. Interpret the contents of
7381 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7382 If the buffer cannot be interpreted, return NULL_TREE. */
7384 static tree
7386 {
7400 {
7403 {
7410 else
7412 }
7413 else
7419 else
7422 }
7425 }
7428 /* Subroutine of native_interpret_expr. Interpret the contents of
7429 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7430 If the buffer cannot be interpreted, return NULL_TREE. */
7432 static tree
7434 {
7439 /* There are always 32 bits in each long, no matter the size of
7440 the hosts long. We handle floating point representations with
7441 up to 192 bits. */
7442 REAL_VALUE_TYPE r;
7453 {
7456 {
7463 else
7465 }
7466 else
7471 }
7475 }
7478 /* Subroutine of native_interpret_expr. Interpret the contents of
7479 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7480 If the buffer cannot be interpreted, return NULL_TREE. */
7482 static tree
7484 {
7499 }
7502 /* Subroutine of native_interpret_expr. Interpret the contents of
7503 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7504 If the buffer cannot be interpreted, return NULL_TREE. */
7506 static tree
7508 {
7520 {
7525 }
7527 }
7530 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7531 the buffer PTR of length LEN as a constant of type TYPE. For
7532 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7533 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7534 return NULL_TREE. */
7536 tree
7538 {
7540 {
7557 }
7558 }
7561 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7562 TYPE at compile-time. If we're unable to perform the conversion
7563 return NULL_TREE. */
7565 static tree
7567 {
7568 /* We support up to 512-bit values (for V8DFmode). */
7572 /* Check that the host and target are sane. */
7581 }
7583 /* Build an expression for the address of T. Folds away INDIRECT_REF
7584 to avoid confusing the gimplify process. When IN_FOLD is true
7585 avoid modifications of T. */
7587 static tree
7589 {
7590 /* The size of the object is not relevant when talking about its address. */
7594 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7597 {
7602 }
7604 {
7614 }
7615 else
7619 }
7621 /* Build an expression for the address of T with type PTRTYPE. This
7622 function modifies the input parameter 'T' by sometimes setting the
7623 TREE_ADDRESSABLE flag. */
7625 tree
7627 {
7629 }
7631 /* Build an expression for the address of T. This function modifies
7632 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7633 flag. When called from fold functions, use fold_addr_expr instead. */
7635 tree
7637 {
7641 }
7643 /* Same as build_fold_addr_expr, builds an expression for the address
7644 of T, but avoids touching the input node 't'. Fold functions
7645 should use this version. */
7647 static tree
7649 {
7653 }
7655 /* Fold a unary expression of code CODE and type TYPE with operand
7656 OP0. Return the folded expression if folding is successful.
7657 Otherwise, return NULL_TREE. */
7659 tree
7661 {
7662 tree tem;
7663 tree arg0;
7671 {
7674 {
7675 /* Don't use STRIP_NOPS, because signedness of argument type
7676 matters. */
7678 }
7679 else
7680 {
7681 /* Strip any conversions that don't change the mode. This
7682 is safe for every expression, except for a comparison
7683 expression because its signedness is derived from its
7684 operands.
7686 Note that this is done as an internal manipulation within
7687 the constant folder, in order to find the simplest
7688 representation of the arguments so that their form can be
7689 studied. In any cases, the appropriate type conversions
7690 should be put back in the tree that will get out of the
7691 constant folder. */
7693 }
7694 }
7697 {
7702 {
7712 /* If this was a conversion, and all we did was to move into
7713 inside the COND_EXPR, bring it back out. But leave it if
7714 it is a conversion from integer to integer and the
7715 result precision is no wider than a word since such a
7716 conversion is cheap and may be optimized away by combine,
7717 while it couldn't if it were outside the COND_EXPR. Then return
7718 so we don't get into an infinite recursion loop taking the
7719 conversion out and then back in. */
7731 && (INTEGRAL_TYPE_P
7743 }
7745 {
7747 {
7751 }
7755 integer_one_node),
7757 integer_zero_node));
7758 }
7759 }
7762 {
7764 /* Re-association barriers around constants and other re-association
7765 barriers can be removed. */
7771 CASE_CONVERT:
7777 /* If we have (type) (a CMP b) and type is an integral type, return
7778 new expression involving the new type. */
7783 /* Handle cases of two conversions in a row. */
7785 {
7807 /* In addition to the cases of two conversions in a row
7808 handled below, if we are converting something to its own
7809 type via an object of identical or wider precision, neither
7810 conversion is needed. */
7817 /* Likewise, if the intermediate and final types are either both
7818 float or both integer, we don't need the middle conversion if
7819 it is wider than the final type and doesn't change the signedness
7820 (for integers). Avoid this if the final type is a pointer
7821 since then we sometimes need the inner conversion. Likewise if
7822 the outer has a precision not equal to the size of its mode. */
7831 && ! final_ptr
7835 /* If we have a sign-extension of a zero-extended value, we can
7836 replace that by a single zero-extension. */
7842 /* Two conversions in a row are not needed unless:
7843 - some conversion is floating-point (overstrict for now), or
7844 - some conversion is a vector (overstrict for now), or
7845 - the intermediate type is narrower than both initial and
7846 final, or
7847 - the intermediate type and innermost type differ in signedness,
7848 and the outermost type is wider than the intermediate, or
7849 - the initial type is a pointer type and the precisions of the
7850 intermediate and final types differ, or
7851 - the final type is a pointer type and the precisions of the
7852 initial and intermediate types differ. */
7866 }
7868 /* Handle (T *)&A.B.C for A being of type T and B and C
7869 living at offset zero. This occurs frequently in
7870 C++ upcasting and then accessing the base. */
7874 {
7876 tree offset;
7882 /* If the reference was to a (constant) zero offset, we can use
7883 the address of the base if it has the same base type
7884 as the result type. */
7889 }
7893 /* Detect assigning a bitfield. */
7895 && DECL_BIT_FIELD
7897 {
7898 /* Don't leave an assignment inside a conversion
7899 unless assigning a bitfield. */
7901 /* First do the assignment, then return converted constant. */
7906 }
7908 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7909 constants (if x has signed type, the sign bit cannot be set
7910 in c). This folds extension into the BIT_AND_EXPR.
7911 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7912 very likely don't have maximal range for their precision and this
7913 transformation effectively doesn't preserve non-maximal ranges. */
7917 /* Not if the conversion is to the sub-type. */
7919 {
7929 <= HOST_BITS_PER_WIDE_INT
7931 {
7938 #ifdef LOAD_EXTEND_OP
7940 && !flag_syntax_only
7943 {
7947 }
7948 #endif
7949 }
7951 {
7957 }
7958 }
7960 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7961 when one of the new casts will fold away. Conservatively we assume
7962 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7968 {
7974 }
7976 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7977 of the same precision, and X is an integer type not narrower than
7978 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7984 {
7989 }
7991 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7992 type of X and Y (integer types only). */
7997 {
7998 /* Be careful not to introduce new overflows. */
7999 tree mult_type;
8002 else
8009 }
8024 /* For integral conversions with the same precision or pointer
8025 conversions use a NOP_EXPR instead. */
8031 /* Do not muck with VIEW_CONVERT_EXPRs that convert from
8032 a sub-type to its base type as generated by the Ada FE. */
8037 /* Strip inner integral conversions that do not change the precision. */
8060 /* Convert fabs((double)float) into (double)fabsf(float). */
8063 {
8068 targ0));
8069 }
8070 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8076 /* Strip sign ops from argument. */
8078 {
8082 }
8089 {
8094 }
8096 {
8101 }
8111 /* Convert ~ (-A) to A - 1. */
8116 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8124 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8137 /* Perform BIT_NOT_EXPR on each element individually. */
8139 {
8144 {
8146 {
8152 }
8153 else
8156 }
8159 }
8164 /* The argument to invert_truthvalue must have Boolean type. */
8168 /* Note that the operand of this must be an int
8169 and its values must be 0 or 1.
8170 ("true" is a fixed value perhaps depending on the language,
8171 but we don't handle values other than 1 correctly yet.) */
8186 {
8194 }
8196 {
8200 }
8202 {
8206 {
8215 }
8216 }
8228 {
8236 }
8238 {
8242 }
8244 {
8248 {
8257 }
8258 }
8264 }
8266 /* Fold a binary expression of code CODE and type TYPE with operands
8267 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8268 Return the folded expression if folding is successful. Otherwise,
8269 return NULL_TREE. */
8271 static tree
8273 {
8280 else
8283 /* MIN (MAX (a, b), b) == b. */
8288 /* MIN (MAX (b, a), b) == b. */
8294 /* MIN (a, MAX (a, b)) == a. */
8300 /* MIN (a, MAX (b, a)) == a. */
8307 }
8309 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8310 by changing CODE to reduce the magnitude of constants involved in
8311 ARG0 of the comparison.
8312 Returns a canonicalized comparison tree if a simplification was
8313 possible, otherwise returns NULL_TREE.
8314 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8315 valid if signed overflow is undefined. */
8317 static tree
8321 {
8327 /* Match A +- CST code arg1 and CST code arg1. We can change the
8328 first form only if overflow is undefined. */
8330 /* In principle pointers also have undefined overflow behavior,
8331 but that causes problems elsewhere. */
8339 /* Identify the constant in arg0 and its sign. */
8342 else
8346 /* Overflowed constants and zero will cause problems. */
8351 /* See if we can reduce the magnitude of the constant in
8352 arg0 by changing the comparison code. */
8354 {
8355 /* CST <= arg1 -> CST-1 < arg1. */
8358 /* -CST < arg1 -> -CST-1 <= arg1. */
8361 /* CST > arg1 -> CST-1 >= arg1. */
8364 /* -CST >= arg1 -> -CST-1 > arg1. */
8367 else
8369 /* arg1 code' CST' might be more canonical. */
8371 }
8372 else
8373 {
8374 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8378 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8382 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8386 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8390 else
8393 }
8395 /* Now build the constant reduced in magnitude. But not if that
8396 would produce one outside of its types range. */
8404 /* We cannot swap the comparison here as that would cause us to
8405 endlessly recurse. */
8413 /* If swapping might yield to a more canonical form, do so. */
8416 else
8418 }
8420 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8421 overflow further. Try to decrease the magnitude of constants involved
8422 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8423 and put sole constants at the second argument position.
8424 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8426 static tree
8429 {
8430 tree t;
8435 /* Try canonicalization by simplifying arg0. */
8440 {
8444 }
8446 /* Try canonicalization by simplifying arg1 using the swapped
8447 comparison. */
8455 }
8457 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8458 space. This is used to avoid issuing overflow warnings for
8459 expressions like &p->x which can not wrap. */
8461 static bool
8463 {
8474 {
8477 }
8480 else
8481 {
8484 }
8499 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8500 array. */
8502 {
8503 HOST_WIDE_INT base_size;
8508 }
8511 }
8513 /* Subroutine of fold_binary. This routine performs all of the
8514 transformations that are common to the equality/inequality
8515 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8516 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8517 fold_binary should call fold_binary. Fold a comparison with
8518 tree code CODE and type TYPE with operands OP0 and OP1. Return
8519 the folded comparison or NULL_TREE. */
8521 static tree
8523 {
8536 /* If one arg is a real or integer constant, put it last. */
8540 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8547 {
8551 tree lhs;
8558 /* If the constant operation overflowed this can be
8559 simplified as a comparison against INT_MAX/INT_MIN. */
8562 {
8566 /* Get the sign of the constant on the lhs if the
8567 operation were VARIABLE + CONST1. */
8571 /* The sign of the constant determines if we overflowed
8572 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8573 Canonicalize to the INT_MIN overflow by swapping the comparison
8574 if necessary. */
8578 /* We now can look at the canonicalized case
8579 VARIABLE + 1 CODE2 INT_MIN
8580 and decide on the result. */
8589 }
8594 {
8596 "when changing X +- C1 cmp C2 to "
8598 WARN_STRICT_OVERFLOW_COMPARISON);
8600 }
8601 }
8603 /* For comparisons of pointers we can decompose it to a compile time
8604 comparison of the base objects and the offsets into the object.
8605 This requires at least one operand being an ADDR_EXPR or a
8606 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8612 {
8619 /* Get base and offset for the access. Strip ADDR_EXPR for
8620 get_inner_reference, but put it back by stripping INDIRECT_REF
8621 off the base object if possible. indirect_baseN will be true
8622 if baseN is not an address but refers to the object itself. */
8625 {
8631 else
8633 }
8635 {
8638 }
8642 {
8648 else
8650 }
8652 {
8655 }
8657 /* If we have equivalent bases we might be able to simplify. */
8660 {
8661 /* We can fold this expression to a constant if the non-constant
8662 offset parts are equal. */
8670 {
8677 "occur when comparing P +- C1 with "
8679 WARN_STRICT_OVERFLOW_CONDITIONAL);
8682 {
8696 }
8697 }
8698 /* We can simplify the comparison to a comparison of the variable
8699 offset parts if the constant offset parts are equal.
8700 Be careful to use signed size type here because otherwise we
8701 mess with array offsets in the wrong way. This is possible
8702 because pointer arithmetic is restricted to retain within an
8703 object and overflow on pointer differences is undefined as of
8704 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8708 {
8709 tree signed_size_type_node;
8712 /* By converting to signed size type we cover middle-end pointer
8713 arithmetic which operates on unsigned pointer types of size
8714 type size and ARRAY_REF offsets which are properly sign or
8715 zero extended from their type in case it is narrower than
8716 size type. */
8719 else
8723 else
8731 "occur when comparing P +- C1 with "
8733 WARN_STRICT_OVERFLOW_COMPARISON);
8736 }
8737 }
8738 /* For non-equal bases we can simplify if they are addresses
8739 of local binding decls or constants. */
8741 /* We know that !operand_equal_p (base0, base1, 0)
8742 because the if condition was false. But make
8743 sure two decls are not the same. */
8757 {
8762 }
8763 /* For equal offsets we can simplify to a comparison of the
8764 base addresses. */
8766 && (indirect_base0
8768 && (indirect_base1
8773 {
8779 }
8780 }
8782 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8783 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8784 the resulting offset is smaller in absolute value than the
8785 original one. */
8793 {
8798 tree cst;
8800 "occur when combining constants around "
8803 /* Put the constant on the side where it doesn't overflow and is
8804 of lower absolute value than before. */
8810 {
8813 variable1,
8816 }
8823 {
8828 variable2);
8829 }
8830 }
8832 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8833 signed arithmetic case. That form is created by the compiler
8834 often enough for folding it to be of value. One example is in
8835 computing loop trip counts after Operator Strength Reduction. */
8841 {
8850 "eliminating multiplication in comparison "
8852 WARN_STRICT_OVERFLOW_COMPARISON);
8854 /* If const1 is negative we swap the sense of the comparison. */
8859 }
8866 {
8874 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8879 /* (-a) CMP (-b) -> b CMP a */
8886 {
8887 REAL_VALUE_TYPE cst;
8890 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8897 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8898 /* a CMP (-0) -> a CMP 0 */
8903 /* x != NaN is always true, other ops are always false. */
8906 {
8909 }
8911 /* Fold comparisons against infinity. */
8913 {
8917 }
8918 }
8920 /* If this is a comparison of a real constant with a PLUS_EXPR
8921 or a MINUS_EXPR of a real constant, we can convert it into a
8922 comparison with a revised real constant as long as no overflow
8923 occurs when unsafe_math_optimizations are enabled. */
8935 /* Likewise, we can simplify a comparison of a real constant with
8936 a MINUS_EXPR whose first operand is also a real constant, i.e.
8937 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
8938 floating-point types only if -fassociative-math is set. */
8949 /* Fold comparisons against built-in math functions. */
8951 && flag_unsafe_math_optimizations
8953 {
8957 {
8961 }
8962 }
8963 }
8967 {
8968 /* If we are widening one operand of an integer comparison,
8969 see if the other operand is similarly being widened. Perhaps we
8970 can do the comparison in the narrower type. */
8975 /* Or if we are changing signedness. */
8979 }
8981 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8982 constant, we can simplify it. */
8987 {
8991 }
8993 /* Simplify comparison of something with itself. (For IEEE
8994 floating-point, we can only do some of these simplifications.) */
8996 {
8998 {
9013 /* For NE, we can only do this simplification if integer
9014 or we don't honor IEEE floating point NaNs. */
9018 /* ... fall through ... */
9024 }
9025 }
9027 /* If we are comparing an expression that just has comparisons
9028 of two integer values, arithmetic expressions of those comparisons,
9029 and constants, we can simplify it. There are only three cases
9030 to check: the two values can either be equal, the first can be
9031 greater, or the second can be greater. Fold the expression for
9032 those three values. Since each value must be 0 or 1, we have
9033 eight possibilities, each of which corresponds to the constant 0
9034 or 1 or one of the six possible comparisons.
9036 This handles common cases like (a > b) == 0 but also handles
9037 expressions like ((x > y) - (y > x)) > 0, which supposedly
9038 occur in macroized code. */
9041 {
9046 /* Don't handle degenerate cases here; they should already
9047 have been handled anyway. */
9056 {
9060 /* We can't just pass T to eval_subst in case cval1 or cval2
9061 was the same as ARG1. */
9063 tree high_result
9067 arg1);
9068 tree equal_result
9072 arg1);
9073 tree low_result
9077 arg1);
9079 /* All three of these results should be 0 or 1. Confirm they are.
9080 Then use those values to select the proper code to use. */
9085 {
9086 /* Make a 3-bit mask with the high-order bit being the
9087 value for `>', the next for '=', and the low for '<'. */
9091 {
9093 /* Always false. */
9114 /* Always true. */
9116 }
9121 }
9122 }
9123 }
9125 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9126 into a single range test. */
9134 {
9138 }
9140 /* Fold ~X op ~Y as Y op X. */
9143 {
9148 }
9150 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9153 {
9159 }
9162 }
9165 /* Subroutine of fold_binary. Optimize complex multiplications of the
9166 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9167 argument EXPR represents the expression "z" of type TYPE. */
9169 static tree
9171 {
9176 {
9179 }
9181 {
9184 }
9185 else
9186 {
9190 }
9199 }
9202 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9203 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9204 guarantees that P and N have the same least significant log2(M) bits.
9205 N is not otherwise constrained. In particular, N is not normalized to
9206 0 <= N < M as is common. In general, the precise value of P is unknown.
9207 M is chosen as large as possible such that constant N can be determined.
9209 Returns M and sets *RESIDUE to N. */
9211 static unsigned HOST_WIDE_INT
9213 {
9220 {
9223 {
9225 tree offset;
9233 {
9236 else
9237 /* We don't handle more complicated offset expressions. */
9239 }
9240 }
9244 }
9246 {
9259 {
9262 }
9264 {
9267 {
9270 /* Compute the greatest power-of-2 divisor of op1. */
9274 /* If align is non-zero and less than *modulus, replace
9275 *modulus with align., If align is 0, then either op1 is 0
9276 or the greatest power-of-2 divisor of op1 doesn't fit in an
9277 unsigned HOST_WIDE_INT. In either case, no additional
9278 constraint is imposed. */
9283 }
9284 }
9285 }
9287 /* If we get here, we were unable to determine anything useful about the
9288 expression. */
9290 }
9293 /* Fold a binary expression of code CODE and type TYPE with operands
9294 OP0 and OP1. Return the folded expression if folding is
9295 successful. Otherwise, return NULL_TREE. */
9297 tree
9299 {
9313 /* Strip any conversions that don't change the mode. This is
9314 safe for every expression, except for a comparison expression
9315 because its signedness is derived from its operands. So, in
9316 the latter case, only strip conversions that don't change the
9317 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9318 preserved.
9320 Note that this is done as an internal manipulation within the
9321 constant folder, in order to find the simplest representation
9322 of the arguments so that their form can be studied. In any
9323 cases, the appropriate type conversions should be put back in
9324 the tree that will get out of the constant folder. */
9327 {
9330 }
9331 else
9332 {
9335 }
9337 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9338 constant but we can't do arithmetic on them. */
9345 {
9347 {
9348 /* Make sure type and arg0 have the same saturating flag. */
9352 }
9355 else
9359 {
9363 }
9364 }
9366 /* If this is a commutative operation, and ARG0 is a constant, move it
9367 to ARG1 to reduce the number of tests below. */
9372 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9374 First check for cases where an arithmetic operation is applied to a
9375 compound, conditional, or comparison operation. Push the arithmetic
9376 operation inside the compound or conditional to see if any folding
9377 can then be done. Convert comparison to conditional for this purpose.
9378 The also optimizes non-constant cases that used to be done in
9379 expand_expr.
9381 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9382 one of the operands is a comparison and the other is a comparison, a
9383 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9384 code below would make the expression more complex. Change it to a
9385 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9386 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9398 {
9402 boolean_type_node,
9410 }
9414 {
9420 op1));
9429 {
9435 }
9438 {
9444 }
9445 }
9448 {
9450 /* 0 +p index -> (type)index */
9454 /* PTR +p 0 -> PTR */
9458 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9465 /* index +p PTR -> PTR +p index */
9472 /* (PTR +p B) +p A -> PTR +p (B + A) */
9474 {
9475 tree inner;
9483 }
9485 /* PTR_CST +p CST -> CST1 */
9489 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9490 of the array. Loop optimizer sometimes produce this type of
9491 expressions. */
9493 {
9497 }
9502 /* PTR + INT -> (INT)(PTR p+ INT) */
9507 arg0,
9509 /* INT + PTR -> (INT)(PTR p+ INT) */
9514 arg1,
9516 /* A + (-B) -> A - B */
9521 /* (-A) + B -> B - A */
9529 {
9530 /* Convert ~A + 1 to -A. */
9536 /* ~X + X is -1. */
9539 {
9544 {
9547 }
9548 }
9550 /* X + ~X is -1. */
9553 {
9558 {
9561 }
9562 }
9564 /* X + (X / CST) * -CST is X % CST. */
9569 {
9577 }
9578 }
9580 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9581 same or one. Make sure type is not saturating.
9582 fold_plusminus_mult_expr will re-associate. */
9587 {
9591 }
9594 {
9598 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9599 with a constant, and the two constants have no bits in common,
9600 we should treat this as a BIT_IOR_EXPR since this may produce more
9601 simplifications. */
9609 {
9612 }
9614 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9615 (plus (plus (mult) (mult)) (foo)) so that we can
9616 take advantage of the factoring cases below. */
9623 {
9629 else
9651 parg1)));
9652 }
9653 }
9654 else
9655 {
9656 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9660 /* Likewise if the operands are reversed. */
9664 /* Convert X + -C into X - C. */
9667 {
9673 }
9675 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9676 to __complex__ ( x, y ). This is not the same for SNaNs or
9677 if signed zeros are involved. */
9681 {
9688 {
9692 {
9698 }
9700 {
9706 }
9707 }
9708 }
9716 /* Convert x+x into x*2.0. */
9722 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9723 We associate floats only if the user has specified
9724 -fassociative-math. */
9728 {
9733 {
9734 tree tree0;
9737 }
9738 }
9739 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9740 We associate floats only if the user has specified
9741 -fassociative-math. */
9745 {
9750 {
9751 tree tree0;
9754 }
9755 }
9756 }
9758 bit_rotate:
9759 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9760 is a rotate of A by C1 bits. */
9761 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9762 is a rotate of A by B bits. */
9763 {
9765 tree rtype;
9774 /* Only create rotates in complete modes. Other cases are not
9775 expanded properly. */
9777 {
9796 {
9804 TYPE_PRECISION
9809 ? LROTATE_EXPR
9812 }
9814 {
9822 TYPE_PRECISION
9827 ? LROTATE_EXPR
9830 }
9831 }
9832 }
9834 associate:
9835 /* In most languages, can't associate operations on floats through
9836 parentheses. Rather than remember where the parentheses were, we
9837 don't associate floats at all, unless the user has specified
9838 -fassociative-math.
9839 And, we need to make sure type is not saturating. */
9843 {
9848 /* Split both trees into variables, constants, and literals. Then
9849 associate each group together, the constants with literals,
9850 then the result with variables. This increases the chances of
9851 literals being recombined later and of generating relocatable
9852 expressions for the sum of a constant and literal. */
9857 /* With undefined overflow we can only associate constants
9858 with one variable. */
9862 {
9870 /* The only case we can still associate with two variables
9871 is if they are the same, modulo negation. */
9874 }
9876 /* Only do something if we found more than two objects. Otherwise,
9877 nothing has changed and we risk infinite recursion. */
9883 {
9884 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9893 /* Preserve the MINUS_EXPR if the negative part of the literal is
9894 greater than the positive part. Otherwise, the multiplicative
9895 folding code (i.e extract_muldiv) may be fooled in case
9896 unsigned constants are subtracted, like in the following
9897 example: ((X*2 + 4) - 8U)/2. */
9899 {
9903 {
9907 }
9908 else
9909 {
9913 }
9914 }
9916 {
9921 else
9922 {
9928 }
9929 }
9934 }
9935 }
9940 /* Pointer simplifications for subtraction, simple reassociations. */
9942 {
9943 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
9946 {
9954 }
9955 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
9957 {
9963 }
9964 }
9965 /* A - (-B) -> A + B */
9969 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9978 /* Convert -A - 1 to ~A. */
9986 /* Convert -1 - A to ~A. */
9992 /* X - (X / CST) * CST is X % CST. */
10005 {
10011 /* Fold A - (A & B) into ~B & A. */
10014 {
10016 {
10021 }
10023 {
10028 }
10029 }
10031 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10032 any power of 2 minus 1. */
10037 {
10043 {
10047 }
10048 }
10049 }
10051 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10055 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10056 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10057 (-ARG1 + ARG0) reduces to -ARG1. */
10061 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10062 __complex__ ( x, -y ). This is not the same for SNaNs or if
10063 signed zeros are involved. */
10067 {
10074 {
10078 {
10080 arg1r ? arg1r
10085 }
10087 {
10091 arg1i ? arg1i
10094 }
10095 }
10096 }
10098 /* Fold &x - &x. This can happen from &x.foo - &x.
10099 This is unsafe for certain floats even in non-IEEE formats.
10100 In IEEE, it is unsafe because it does wrong for NaNs.
10101 Also note that operand_equal_p is always false if an operand
10102 is volatile. */
10108 /* A - B -> A + (-B) if B is easily negatable. */
10111 /* Avoid this transformation if B is a positive REAL_CST. */
10119 /* Try folding difference of addresses. */
10120 {
10121 HOST_WIDE_INT diff;
10127 }
10129 /* Fold &a[i] - &a[j] to i-j. */
10134 {
10139 {
10147 }
10148 }
10156 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10157 same or one. Make sure type is not saturating.
10158 fold_plusminus_mult_expr will re-associate. */
10163 {
10167 }
10172 /* (-A) * (-B) -> A * B */
10183 {
10188 /* Transform x * -1 into -x. Make sure to do the negation
10189 on the original operand with conversions not stripped
10190 because we can only strip non-sign-changing conversions. */
10193 /* Transform x * -C into -x * C if x is easily negatable. */
10202 /* (a * (1 << b)) is (a << b) */
10212 /* (A + A) * C -> A * 2 * C */
10227 {
10230 "occur when simplifying "
10232 WARN_STRICT_OVERFLOW_MISC);
10234 }
10236 /* Optimize z * conj(z) for integer complex numbers. */
10243 }
10244 else
10245 {
10246 /* Maybe fold x * 0 to 0. The expressions aren't the same
10247 when x is NaN, since x * 0 is also NaN. Nor are they the
10248 same in modes with signed zeros, since multiplying a
10249 negative value by 0 gives -0, not +0. */
10254 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10259 /* Transform x * -1.0 into -x. */
10264 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10265 the result for floating point types due to rounding so it is applied
10266 only if -fassociative-math was specify. */
10271 {
10277 }
10279 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10281 {
10284 {
10287 }
10288 }
10290 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10291 This is not the same for NaNs or if signed zeros are
10292 involved. */
10298 {
10310 }
10312 /* Optimize z * conj(z) for floating point complex numbers.
10313 Guarded by flag_unsafe_math_optimizations as non-finite
10314 imaginary components don't produce scalar results. */
10325 {
10329 /* Optimizations of root(...)*root(...). */
10331 {
10336 /* Optimize sqrt(x)*sqrt(x) as x. */
10342 /* Optimize root(x)*root(y) as root(x*y). */
10346 }
10348 /* Optimize expN(x)*expN(y) as expN(x+y). */
10350 {
10356 }
10358 /* Optimizations of pow(...)*pow(...). */
10362 {
10368 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10370 {
10374 }
10376 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10378 {
10382 }
10383 }
10385 /* Optimize tan(x)*cos(x) as sin(x). */
10394 {
10399 }
10401 /* Optimize x*pow(x,c) as pow(x,c+1). */
10405 {
10411 {
10413 REAL_VALUE_TYPE c;
10414 tree arg;
10420 }
10421 }
10423 /* Optimize pow(x,c)*x as pow(x,c+1). */
10427 {
10433 {
10435 REAL_VALUE_TYPE c;
10436 tree arg;
10442 }
10443 }
10445 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10448 {
10452 {
10455 }
10456 }
10457 }
10458 }
10462 bit_ior:
10470 /* ~X | X is -1. */
10473 {
10477 }
10479 /* X | ~X is -1. */
10482 {
10486 }
10488 /* Canonicalize (X & C1) | C2. */
10492 {
10500 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10505 {
10509 }
10510 else
10511 {
10515 }
10517 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10522 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10523 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10524 mode which allows further optimizations. */
10534 {
10535 unsigned HOST_WIDE_INT mask
10539 {
10543 }
10544 }
10551 arg1);
10552 }
10554 /* (X & Y) | Y is (X, Y). */
10558 /* (X & Y) | X is (Y, X). */
10563 /* X | (X & Y) is (Y, X). */
10568 /* X | (Y & X) is (Y, X). */
10578 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10580 This results in more efficient code for machines without a NAND
10581 instruction. Combine will canonicalize to the first form
10582 which will allow use of NAND instructions provided by the
10583 backend if they exist. */
10586 {
10593 }
10595 /* See if this can be simplified into a rotate first. If that
10596 is unsuccessful continue in the association code. */
10607 /* ~X ^ X is -1. */
10610 {
10614 }
10616 /* X ^ ~X is -1. */
10619 {
10623 }
10625 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10626 with a constant, and the two constants have no bits in common,
10627 we should treat this as a BIT_IOR_EXPR since this may produce more
10628 simplifications. */
10636 {
10639 }
10641 /* (X | Y) ^ X -> Y & ~ X*/
10644 {
10647 arg1);
10651 }
10653 /* (Y | X) ^ X -> Y & ~ X*/
10656 {
10659 arg1);
10663 }
10665 /* X ^ (X | Y) -> Y & ~ X*/
10668 {
10671 arg0);
10675 }
10677 /* X ^ (Y | X) -> Y & ~ X*/
10680 {
10683 arg0);
10687 }
10689 /* Convert ~X ^ ~Y to X ^ Y. */
10696 /* Convert ~X ^ C to X ^ ~C. */
10703 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10710 /* Fold (X & Y) ^ Y as ~X & Y. */
10713 {
10718 }
10719 /* Fold (X & Y) ^ X as ~Y & X. */
10723 {
10728 }
10729 /* Fold X ^ (X & Y) as X & ~Y. */
10732 {
10737 }
10738 /* Fold X ^ (Y & X) as ~Y & X. */
10742 {
10747 }
10749 /* See if this can be simplified into a rotate first. If that
10750 is unsuccessful continue in the association code. */
10761 /* ~X & X is always zero. */
10766 /* X & ~X is always zero. */
10771 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10775 {
10783 }
10785 /* (X | Y) & Y is (X, Y). */
10789 /* (X | Y) & X is (Y, X). */
10794 /* X & (X | Y) is (Y, X). */
10799 /* X & (Y | X) is (Y, X). */
10805 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10809 {
10815 }
10816 /* Fold ~X & 1 as (X & 1) == 0. */
10819 {
10825 }
10827 /* Fold (X ^ Y) & Y as ~X & Y. */
10830 {
10835 }
10836 /* Fold (X ^ Y) & X as ~Y & X. */
10840 {
10845 }
10846 /* Fold X & (X ^ Y) as X & ~Y. */
10849 {
10854 }
10855 /* Fold X & (Y ^ X) as ~Y & X. */
10859 {
10864 }
10869 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10872 {
10873 unsigned int prec
10880 }
10882 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10884 This results in more efficient code for machines without a NOR
10885 instruction. Combine will canonicalize to the first form
10886 which will allow use of NOR instructions provided by the
10887 backend if they exist. */
10890 {
10897 }
10899 /* If arg0 is derived from the address of an object or function, we may
10900 be able to fold this expression using the object or function's
10901 alignment. */
10903 {
10909 /* This works because modulus is a power of 2. If this weren't the
10910 case, we'd have to replace it by its greatest power-of-2
10911 divisor: modulus & -modulus. */
10914 }
10916 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
10917 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
10918 if the new mask might be further optimized. */
10927 {
10929 unsigned HOST_WIDE_INT mask
10939 {
10942 /* See if more bits can be proven as zero because of
10943 zero extension. */
10946 {
10951 {
10953 /* See if we can shorten the right shift. */
10956 }
10957 }
10961 /* For arithmetic shift if sign bit could be set, zerobits
10962 can contain actually sign bits, so no transformation is
10963 possible, unless MASK masks them all away. In that
10964 case the shift needs to be converted into logical shift. */
10967 {
10970 else
10972 }
10973 }
10975 /* ((X << 16) & 0xff00) is (X, 0). */
10981 {
10984 /* Only do the transformation if NEWMASK is some integer
10985 mode's mask. */
10992 {
10994 {
11000 }
11001 else
11005 newmask));
11006 }
11007 }
11008 }
11013 /* Don't touch a floating-point divide by zero unless the mode
11014 of the constant can represent infinity. */
11020 /* Optimize A / A to 1.0 if we don't care about
11021 NaNs or Infinities. Skip the transformation
11022 for non-real operands. */
11027 {
11031 }
11033 /* The complex version of the above A / A optimization. */
11036 {
11040 {
11042 /* omit_two_operands will call fold_convert for us. */
11044 }
11045 }
11047 /* (-A) / (-B) -> A / B */
11057 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11062 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11067 /* If ARG1 is a constant, we can convert this to a multiply by the
11068 reciprocal. This does not have the same rounding properties,
11069 so only do this if -freciprocal-math. We can actually
11070 always safely do it if ARG1 is a power of two, but it's hard to
11071 tell if it is or not in a portable manner. */
11073 {
11078 /* Find the reciprocal if optimizing and the result is exact. */
11080 {
11081 REAL_VALUE_TYPE r;
11084 {
11088 }
11089 }
11090 }
11091 /* Convert A/B/C to A/(B*C). */
11098 /* Convert A/(B/C) to (A/B)*C. */
11106 /* Convert C1/(X*C2) into (C1/C2)/X. */
11111 {
11117 }
11120 {
11124 /* Optimize sin(x)/cos(x) as tan(x). */
11130 {
11135 }
11137 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11143 {
11147 {
11151 }
11152 }
11154 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11155 NaNs or Infinities. */
11159 {
11166 {
11171 }
11172 }
11174 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11175 NaNs or Infinities. */
11179 {
11186 {
11190 {
11194 tmp);
11195 }
11196 }
11197 }
11199 /* Optimize pow(x,c)/x as pow(x,c-1). */
11203 {
11209 {
11211 REAL_VALUE_TYPE c;
11212 tree arg;
11218 }
11219 }
11221 /* Optimize a/root(b/c) into a*root(c/b). */
11223 {
11227 {
11236 }
11237 }
11239 /* Optimize x/expN(y) into x*expN(-y). */
11241 {
11246 }
11248 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11252 {
11259 }
11260 }
11265 /* Simplify A / (B << N) where A and B are positive and B is
11266 a power of 2, to A >> (N + log2(B)). */
11271 {
11274 {
11281 WARN_STRICT_OVERFLOW_MISC);
11287 }
11288 }
11290 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11291 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11297 /* Fall thru */
11306 /* X / -1 is -X. */
11313 /* Convert -A / -B to A / B when the type is signed and overflow is
11314 undefined. */
11318 {
11321 "when distributing negation across "
11323 WARN_STRICT_OVERFLOW_MISC);
11327 }
11331 {
11334 "when distributing negation across "
11336 WARN_STRICT_OVERFLOW_MISC);
11339 }
11341 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11342 operation, EXACT_DIV_EXPR.
11344 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11345 At one time others generated faster code, it's not clear if they do
11346 after the last round to changes to the DIV code in expmed.c. */
11355 {
11359 WARN_STRICT_OVERFLOW_MISC);
11361 }
11369 /* X % 1 is always zero, but be sure to preserve any side
11370 effects in X. */
11374 /* X % 0, return X % 0 unchanged so that we can get the
11375 proper warnings and errors. */
11379 /* 0 % X is always zero, but be sure to preserve any side
11380 effects in X. Place this after checking for X == 0. */
11384 /* X % -1 is zero. */
11391 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11392 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11397 {
11399 /* Also optimize A % (C << N) where C is a power of 2,
11400 to A & ((C << N) - 1). */
11405 {
11410 "occur when simplifying "
11412 WARN_STRICT_OVERFLOW_MISC);
11416 }
11417 }
11419 /* X % -C is the same as X % C. */
11426 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11431 /* X % -Y is the same as X % Y. */
11442 {
11446 WARN_STRICT_OVERFLOW_MISC);
11448 }
11459 /* Optimize -1 >> x for arithmetic right shifts. */
11462 /* ... fall through ... */
11465 shift:
11471 /* Since negative shift count is not well-defined,
11472 don't try to compute it in the compiler. */
11476 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11481 {
11485 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11486 being well defined. */
11488 {
11493 else
11495 }
11499 }
11501 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11502 into x & ((unsigned)-1 >> c) for unsigned types. */
11510 {
11513 tree lshift;
11514 tree arg00;
11517 {
11524 }
11525 }
11527 /* Rewrite an LROTATE_EXPR by a constant into an
11528 RROTATE_EXPR by a new constant. */
11530 {
11535 }
11537 /* If we have a rotate of a bit operation with the rotate count and
11538 the second operand of the bit operation both constant,
11539 permute the two operations. */
11551 /* Two consecutive rotates adding up to the precision of the
11552 type can be ignored. */
11563 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11564 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11565 if the latter can be further optimized. */
11570 {
11573 arg1);
11576 arg1);
11580 }
11608 /* Note that the operands of this must be ints
11609 and their values must be 0 or 1.
11610 ("true" is a fixed value perhaps depending on the language.) */
11611 /* If first arg is constant zero, return it. */
11615 /* If either arg is constant true, drop it. */
11619 /* Preserve sequence points. */
11622 /* If second arg is constant zero, result is zero, but first arg
11623 must be evaluated. */
11626 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11627 case will be handled here. */
11631 /* !X && X is always false. */
11635 /* X && !X is always false. */
11640 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11641 means A >= Y && A != MAX, but in this case we know that
11642 A < X <= MAX. */
11646 {
11654 }
11656 truth_andor:
11657 /* We only do these simplifications if we are optimizing. */
11661 /* Check for things like (A || B) && (A || C). We can convert this
11662 to A || (B && C). Note that either operator can be any of the four
11663 truth and/or operations and the transformation will still be
11664 valid. Also note that we only care about order for the
11665 ANDIF and ORIF operators. If B contains side effects, this
11666 might change the truth-value of A. */
11673 {
11693 /* This case if tricky because we must either have commutative
11694 operators or else A10 must not have side-effects. */
11700 a01);
11701 }
11703 /* See if we can build a range comparison. */
11707 /* Check for the possibility of merging component references. If our
11708 lhs is another similar operation, try to merge its rhs with our
11709 rhs. Then try to merge our lhs and rhs. */
11721 /* Note that the operands of this must be ints
11722 and their values must be 0 or true.
11723 ("true" is a fixed value perhaps depending on the language.) */
11724 /* If first arg is constant true, return it. */
11728 /* If either arg is constant zero, drop it. */
11732 /* Preserve sequence points. */
11735 /* If second arg is constant true, result is true, but we must
11736 evaluate first arg. */
11739 /* Likewise for first arg, but note this only occurs here for
11740 TRUTH_OR_EXPR. */
11744 /* !X || X is always true. */
11748 /* X || !X is always true. */
11756 /* If the second arg is constant zero, drop it. */
11759 /* If the second arg is constant true, this is a logical inversion. */
11761 {
11762 /* Only call invert_truthvalue if operand is a truth value. */
11765 else
11768 }
11769 /* Identical arguments cancel to zero. */
11773 /* !X ^ X is always true. */
11778 /* X ^ !X is always true. */
11791 /* bool_var != 0 becomes bool_var. */
11796 /* bool_var == 1 becomes bool_var. */
11801 /* bool_var != 1 becomes !bool_var. */
11806 /* bool_var == 0 becomes !bool_var. */
11811 /* If this is an equality comparison of the address of two non-weak,
11812 unaliased symbols neither of which are extern (since we do not
11813 have access to attributes for externs), then we know the result. */
11826 {
11827 /* We know that we're looking at the address of two
11828 non-weak, unaliased, static _DECL nodes.
11830 It is both wasteful and incorrect to call operand_equal_p
11831 to compare the two ADDR_EXPR nodes. It is wasteful in that
11832 all we need to do is test pointer equality for the arguments
11833 to the two ADDR_EXPR nodes. It is incorrect to use
11834 operand_equal_p as that function is NOT equivalent to a
11835 C equality test. It can in fact return false for two
11836 objects which would test as equal using the C equality
11837 operator. */
11841 type);
11842 }
11844 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11845 a MINUS_EXPR of a constant, we can convert it into a comparison with
11846 a revised constant as long as no overflow occurs. */
11858 /* Similarly for a NEGATE_EXPR. */
11866 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11875 /* Transform comparisons of the form X +- C CMP X. */
11881 {
11888 else
11891 }
11893 /* If we have X - Y == 0, we can convert that to X == Y and similarly
11894 for !=. Don't do this for ordered comparisons due to overflow. */
11900 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11905 /* If this is an EQ or NE comparison with zero and ARG0 is
11906 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11907 two operations, but the latter can be done in one less insn
11908 on machines that have only two-operand insns or on which a
11909 constant cannot be the first operand. */
11912 {
11917 {
11924 }
11927 {
11934 }
11935 }
11937 /* If this is an NE or EQ comparison of zero against the result of a
11938 signed MOD operation whose second operand is a power of 2, make
11939 the MOD operation unsigned since it is simpler and equivalent. */
11947 {
11957 }
11959 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11960 C1 is a valid shift constant, and C2 is a power of two, i.e.
11961 a single bit. */
11965 == INTEGER_CST
11968 {
11973 /* Check for a valid shift count. */
11976 {
11980 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11981 can be rewritten as (X & (C2 << C1)) != 0. */
11983 {
11987 }
11988 /* Otherwise, for signed (arithmetic) shifts,
11989 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11990 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11994 /* Otherwise, of unsigned (logical) shifts,
11995 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11996 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11997 else
12001 arg000);
12002 }
12003 }
12005 /* If this is an NE comparison of zero with an AND of one, remove the
12006 comparison since the AND will give the correct value. */
12013 /* If we have (A & C) == C where C is a power of 2, convert this into
12014 (A & C) != 0. Similarly for NE_EXPR. */
12020 integer_zero_node));
12022 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12023 bit, then fold the expression into A < 0 or A >= 0. */
12028 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12029 Similarly for NE_EXPR. */
12033 {
12042 }
12044 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12045 Similarly for NE_EXPR. */
12049 {
12056 }
12058 /* Optimize comparisons of strlen vs zero to a compare of the
12059 first character of the string vs zero. To wit,
12060 strlen(ptr) == 0 => *ptr == 0
12061 strlen(ptr) != 0 => *ptr != 0
12062 Other cases should reduce to one of these two (or a constant)
12063 due to the return value of strlen being unsigned. */
12066 {
12074 {
12078 }
12079 }
12081 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12082 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12086 {
12093 {
12095 {
12098 }
12101 }
12102 }
12104 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12110 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12115 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12122 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12130 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12131 (X & C) == 0 when C is a single bit. */
12136 {
12142 }
12144 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12145 constant C is a power of two, i.e. a single bit. */
12152 {
12156 }
12158 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12159 when is C is a power of two, i.e. a single bit. */
12166 {
12172 }
12176 {
12179 }
12181 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12188 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12191 {
12203 arg01),
12211 arg01),
12219 arg00),
12227 arg00),
12229 }
12233 {
12240 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12241 operand_equal_p guarantees no side-effects so we don't need
12242 to use omit_one_operand on Z. */
12252 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12259 arg10);
12260 }
12262 /* Attempt to simplify equality/inequality comparisons of complex
12263 values. Only lower the comparison if the result is known or
12264 can be simplified to a single scalar comparison. */
12269 {
12274 {
12277 }
12278 else
12279 {
12282 }
12285 {
12288 }
12289 else
12290 {
12293 }
12297 {
12299 {
12304 }
12305 else
12306 {
12311 }
12312 }
12316 {
12318 {
12323 }
12324 else
12325 {
12330 }
12331 }
12332 }
12344 /* Transform comparisons of the form X +- C CMP X. */
12351 {
12358 else
12361 /* (X - c) > X becomes false. */
12365 {
12369 "occur when assuming that (X - c) > X "
12371 WARN_STRICT_OVERFLOW_ALL);
12373 }
12375 /* Likewise (X + c) < X becomes false. */
12379 {
12383 "occur when assuming that "
12385 WARN_STRICT_OVERFLOW_ALL);
12387 }
12389 /* Convert (X - c) <= X to true. */
12394 {
12398 "occur when assuming that "
12400 WARN_STRICT_OVERFLOW_ALL);
12402 }
12404 /* Convert (X + c) >= X to true. */
12409 {
12413 "occur when assuming that "
12415 WARN_STRICT_OVERFLOW_ALL);
12417 }
12420 {
12421 /* Convert X + c > X and X - c < X to true for integers. */
12425 {
12428 "not occur when assuming that "
12430 WARN_STRICT_OVERFLOW_ALL);
12432 }
12437 {
12440 "not occur when assuming that "
12442 WARN_STRICT_OVERFLOW_ALL);
12444 }
12446 /* Convert X + c <= X and X - c >= X to false for integers. */
12450 {
12453 "not occur when assuming that "
12455 WARN_STRICT_OVERFLOW_ALL);
12457 }
12462 {
12465 "not occur when assuming that "
12467 WARN_STRICT_OVERFLOW_ALL);
12469 }
12470 }
12471 }
12473 /* Comparisons with the highest or lowest possible integer of
12474 the specified precision will have known values. */
12475 {
12482 {
12483 HOST_WIDE_INT signed_max_hi;
12488 {
12495 {
12499 }
12500 else
12501 {
12505 }
12506 }
12507 else
12508 {
12517 {
12520 }
12521 else
12522 {
12525 }
12526 }
12531 {
12544 /* The GE_EXPR and LT_EXPR cases above are not normally
12545 reached because of previous transformations. */
12549 }
12551 == max_hi
12554 {
12560 arg1);
12566 arg1);
12569 }
12571 == min_hi
12574 {
12589 }
12591 == min_hi
12594 {
12599 arg1);
12604 arg1);
12607 }
12612 /* We will flip the signedness of the comparison operator
12613 associated with the mode of arg1, so the sign bit is
12614 specified by this mode. Check that arg1 is the signed
12615 max associated with this sign bit. */
12617 /* signed_type does not work on pointer types. */
12619 {
12620 /* The following case also applies to X < signed_max+1
12621 and X >= signed_max+1 because previous transformations. */
12623 {
12624 tree st;
12629 }
12630 }
12631 }
12632 }
12634 /* If we are comparing an ABS_EXPR with a constant, we can
12635 convert all the cases into explicit comparisons, but they may
12636 well not be faster than doing the ABS and one comparison.
12637 But ABS (X) <= C is a range comparison, which becomes a subtraction
12638 and a comparison, and is probably faster. */
12652 /* Convert ABS_EXPR<x> >= 0 to true. */
12659 {
12662 "when simplifying comparison of "
12664 WARN_STRICT_OVERFLOW_CONDITIONAL);
12666 }
12668 /* Convert ABS_EXPR<x> < 0 to false. */
12673 {
12676 "when simplifying comparison of "
12678 WARN_STRICT_OVERFLOW_CONDITIONAL);
12680 }
12682 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12683 and similarly for >= into !=. */
12698 return
12717 {
12721 }
12723 /* If the first operand is NaN, the result is constant. */
12727 {
12729 ? integer_zero_node
12732 }
12734 /* If the second operand is NaN, the result is constant. */
12738 {
12740 ? integer_zero_node
12743 }
12745 /* Simplify unordered comparison of something with itself. */
12751 && !flag_trapping_math
12755 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12756 {
12767 }
12772 /* When pedantic, a compound expression can be neither an lvalue
12773 nor an integer constant expression. */
12776 /* Don't let (0, 0) be null pointer constant. */
12790 /* An ASSERT_EXPR should never be passed to fold_binary. */
12796 }
12798 /* Callback for walk_tree, looking for LABEL_EXPR.
12799 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12800 Do not check the sub-tree of GOTO_EXPR. */
12802 static tree
12806 {
12808 {
12813 /* no break */
12816 }
12817 }
12819 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12820 accessible from outside the sub-tree. Returns NULL_TREE if no
12821 addressable label is found. */
12823 static bool
12825 {
12827 }
12829 /* Fold a ternary expression of code CODE and type TYPE with operands
12830 OP0, OP1, and OP2. Return the folded expression if folding is
12831 successful. Otherwise, return NULL_TREE. */
12833 tree
12835 {
12836 tree tem;
12843 /* Strip any conversions that don't change the mode. This is safe
12844 for every expression, except for a comparison expression because
12845 its signedness is derived from its operands. So, in the latter
12846 case, only strip conversions that don't change the signedness.
12848 Note that this is done as an internal manipulation within the
12849 constant folder, in order to find the simplest representation of
12850 the arguments so that their form can be studied. In any cases,
12851 the appropriate type conversions should be put back in the tree
12852 that will get out of the constant folder. */
12854 {
12857 }
12860 {
12863 }
12866 {
12870 {
12876 }
12880 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12881 so all simple results must be passed through pedantic_non_lvalue. */
12883 {
12886 /* Only optimize constant conditions when the selected branch
12887 has the same type as the COND_EXPR. This avoids optimizing
12888 away "c ? x : throw", where the throw has a void type.
12889 Avoid throwing away that operand which contains label. */
12896 }
12900 /* If we have A op B ? A : C, we may be able to convert this to a
12901 simpler expression, depending on the operation and the values
12902 of B and C. Signed zeros prevent all of these transformations,
12903 for reasons given above each one.
12905 Also try swapping the arguments and inverting the conditional. */
12910 {
12914 }
12918 op2,
12921 {
12924 {
12928 }
12929 }
12931 /* If the second operand is simpler than the third, swap them
12932 since that produces better jump optimization results. */
12935 {
12936 /* See if this can be inverted. If it can't, possibly because
12937 it was a floating-point inequality comparison, don't do
12938 anything. */
12942 }
12944 /* Convert A ? 1 : 0 to simply A. */
12947 /* If we try to convert OP0 to our type, the
12948 call to fold will try to move the conversion inside
12949 a COND, which will recurse. In that case, the COND_EXPR
12950 is probably the best choice, so leave it alone. */
12954 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12955 over COND_EXPR in cases such as floating point comparisons. */
12962 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12967 {
12968 /* sign_bit_p only checks ARG1 bits within A's precision.
12969 If <sign bit of A> has wider type than A, bits outside
12970 of A's precision in <sign bit of A> need to be checked.
12971 If they are all 0, this optimization needs to be done
12972 in unsigned A's type, if they are all 1 in signed A's type,
12973 otherwise this can't be done. */
12978 {
12980 HOST_WIDE_INT mask_hi;
12982 tree tem_type;
12990 {
12994 }
12995 else
12996 {
13000 }
13002 {
13006 }
13007 else
13013 {
13016 }
13019 {
13022 }
13023 else
13025 }
13032 arg1)));
13033 }
13035 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13036 already handled above. */
13041 {
13050 }
13052 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13053 is probably obsolete because the first operand should be a
13054 truth value (that's why we have the two cases above), but let's
13055 leave it in until we can confirm this for all front-ends. */
13066 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13072 arg1);
13074 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13078 {
13079 /* Only perform transformation if ARG0 is easily inverted. */
13084 arg1);
13085 }
13087 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13091 {
13092 /* Only perform transformation if ARG0 is easily inverted. */
13097 op2);
13098 }
13100 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13106 op2);
13111 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13112 of fold_ternary on them. */
13119 {
13128 {
13133 else
13134 {
13136 tree value;
13140 }
13145 else
13147 }
13148 }
13150 /* A bit-field-ref that referenced the full argument can be stripped. */
13161 }
13163 /* Perform constant folding and related simplification of EXPR.
13164 The related simplifications include x*1 => x, x*0 => 0, etc.,
13165 and application of the associative law.
13166 NOP_EXPR conversions may be removed freely (as long as we
13167 are careful not to change the type of the overall expression).
13168 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13169 but we can constant-fold them if they have constant operands. */
13171 #ifdef ENABLE_FOLD_CHECKING
13172 # define fold(x) fold_1 (x)
13174 static
13175 #endif
13176 tree
13178 {
13182 tree tem;
13184 /* Return right away if a constant. */
13188 /* CALL_EXPR-like objects with variable numbers of operands are
13189 treated specially. */
13191 {
13193 {
13196 }
13198 }
13201 {
13206 {
13224 }
13225 }
13228 {
13230 {
13237 {
13242 /* Find a matching index by means of a binary search. */
13244 {
13260 else
13262 }
13263 }
13266 }
13274 }
13276 #ifdef ENABLE_FOLD_CHECKING
13277 #undef fold
13283 /* When --enable-checking=fold, compute a digest of expr before
13284 and after actual fold call to see if fold did not accidentally
13285 change original expr. */
13287 tree
13289 {
13290 tree ret;
13293 htab_t ht;
13312 }
13314 void
13316 {
13319 htab_t ht;
13329 }
13331 static void
13333 {
13335 }
13337 static void
13339 {
13345 recursive_label:
13359 {
13360 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13364 }
13369 {
13370 /* Allow these fields to be modified. */
13371 tree tmp;
13378 {
13381 }
13382 }
13391 {
13394 {
13408 }
13412 {
13425 }
13442 {
13448 }
13453 {
13457 }
13468 {
13471 }
13481 }
13482 }
13484 /* Helper function for outputting the checksum of a tree T. When
13485 debugging with gdb, you can "define mynext" to be "next" followed
13486 by "call debug_fold_checksum (op0)", then just trace down till the
13487 outputs differ. */
13489 void
13491 {
13506 }
13508 #endif
13510 /* Fold a unary tree expression with code CODE of type TYPE with an
13511 operand OP0. Return a folded expression if successful. Otherwise,
13512 return a tree expression with code CODE of type TYPE with an
13513 operand OP0. */
13515 tree
13517 {
13518 tree tem;
13519 #ifdef ENABLE_FOLD_CHECKING
13522 htab_t ht;
13529 #endif
13535 #ifdef ENABLE_FOLD_CHECKING
13543 #endif
13545 }
13547 /* Fold a binary tree expression with code CODE of type TYPE with
13548 operands OP0 and OP1. Return a folded expression if successful.
13549 Otherwise, return a tree expression with code CODE of type TYPE
13550 with operands OP0 and OP1. */
13552 tree
13554 MEM_STAT_DECL)
13555 {
13556 tree tem;
13557 #ifdef ENABLE_FOLD_CHECKING
13563 htab_t ht;
13575 #endif
13581 #ifdef ENABLE_FOLD_CHECKING
13597 #endif
13599 }
13601 /* Fold a ternary tree expression with code CODE of type TYPE with
13602 operands OP0, OP1, and OP2. Return a folded expression if
13603 successful. Otherwise, return a tree expression with code CODE of
13604 type TYPE with operands OP0, OP1, and OP2. */
13606 tree
13608 MEM_STAT_DECL)
13609 {
13610 tree tem;
13611 #ifdef ENABLE_FOLD_CHECKING
13619 htab_t ht;
13636 #endif
13643 #ifdef ENABLE_FOLD_CHECKING
13667 #endif
13669 }
13671 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13672 arguments in ARGARRAY, and a null static chain.
13673 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13674 of type TYPE from the given operands as constructed by build_call_array. */
13676 tree
13678 {
13679 tree tem;
13680 #ifdef ENABLE_FOLD_CHECKING
13686 htab_t ht;
13700 #endif
13704 #ifdef ENABLE_FOLD_CHECKING
13721 #endif
13723 }
13725 /* Perform constant folding and related simplification of initializer
13726 expression EXPR. These behave identically to "fold_buildN" but ignore
13727 potential run-time traps and exceptions that fold must preserve. */
13729 #define START_FOLD_INIT \
13730 int saved_signaling_nans = flag_signaling_nans;\
13731 int saved_trapping_math = flag_trapping_math;\
13732 int saved_rounding_math = flag_rounding_math;\
13733 int saved_trapv = flag_trapv;\
13734 int saved_folding_initializer = folding_initializer;\
13735 flag_signaling_nans = 0;\
13736 flag_trapping_math = 0;\
13737 flag_rounding_math = 0;\
13738 flag_trapv = 0;\
13739 folding_initializer = 1;
13741 #define END_FOLD_INIT \
13742 flag_signaling_nans = saved_signaling_nans;\
13743 flag_trapping_math = saved_trapping_math;\
13744 flag_rounding_math = saved_rounding_math;\
13745 flag_trapv = saved_trapv;\
13746 folding_initializer = saved_folding_initializer;
13748 tree
13750 {
13751 tree result;
13752 START_FOLD_INIT;
13756 END_FOLD_INIT;
13758 }
13760 tree
13762 {
13763 tree result;
13764 START_FOLD_INIT;
13768 END_FOLD_INIT;
13770 }
13772 tree
13774 tree op2)
13775 {
13776 tree result;
13777 START_FOLD_INIT;
13781 END_FOLD_INIT;
13783 }
13785 tree
13788 {
13789 tree result;
13790 START_FOLD_INIT;
13794 END_FOLD_INIT;
13796 }
13798 #undef START_FOLD_INIT
13799 #undef END_FOLD_INIT
13801 /* Determine if first argument is a multiple of second argument. Return 0 if
13802 it is not, or we cannot easily determined it to be.
13804 An example of the sort of thing we care about (at this point; this routine
13805 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13806 fold cases do now) is discovering that
13808 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13810 is a multiple of
13812 SAVE_EXPR (J * 8)
13814 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13816 This code also handles discovering that
13818 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13820 is a multiple of 8 so we don't have to worry about dealing with a
13821 possible remainder.
13823 Note that we *look* inside a SAVE_EXPR only to determine how it was
13824 calculated; it is not safe for fold to do much of anything else with the
13825 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13826 at run time. For example, the latter example above *cannot* be implemented
13827 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13828 evaluation time of the original SAVE_EXPR is not necessarily the same at
13829 the time the new expression is evaluated. The only optimization of this
13830 sort that would be valid is changing
13832 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13834 divided by 8 to
13836 SAVE_EXPR (I) * SAVE_EXPR (J)
13838 (where the same SAVE_EXPR (J) is used in the original and the
13839 transformed version). */
13841 int
13843 {
13851 {
13853 /* Bitwise and provides a power of two multiple. If the mask is
13854 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13857 /* FALLTHRU */
13870 {
13874 /* const_binop may not detect overflow correctly,
13875 so check for it explicitly here. */
13881 size_one_node,
13885 }
13889 /* Can't handle conversions from non-integral or wider integral type. */
13895 /* .. fall through ... */
13912 }
13913 }
13915 /* Return true if CODE or TYPE is known to be non-negative. */
13917 static bool
13919 {
13922 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13923 have a signed:1 type (where the value is -1 and 0). */
13926 }
13928 /* Return true if (CODE OP0) is known to be non-negative. If the return
13929 value is based on the assumption that signed overflow is undefined,
13930 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13931 *STRICT_OVERFLOW_P. */
13933 bool
13936 {
13941 {
13943 /* We can't return 1 if flag_wrapv is set because
13944 ABS_EXPR<INT_MIN> = INT_MIN. */
13948 {
13951 }
13958 strict_overflow_p);
13961 {
13966 {
13969 strict_overflow_p);
13971 {
13975 strict_overflow_p);
13976 }
13977 }
13979 {
13982 strict_overflow_p);
13986 }
13987 }
13992 }
13994 /* We don't know sign of `t', so be conservative and return false. */
13996 }
13998 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13999 value is based on the assumption that signed overflow is undefined,
14000 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14001 *STRICT_OVERFLOW_P. */
14003 bool
14006 {
14011 {
14016 strict_overflow_p)
14018 strict_overflow_p));
14020 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14021 both unsigned and at least 2 bits shorter than the result. */
14025 {
14030 {
14034 }
14035 }
14040 {
14041 /* x * x for floating point x is always non-negative. */
14045 strict_overflow_p)
14047 strict_overflow_p));
14048 }
14050 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14051 both unsigned and their total bits is shorter than the result. */
14055 {
14074 {
14084 }
14085 }
14091 strict_overflow_p)
14093 strict_overflow_p));
14104 strict_overflow_p)
14106 strict_overflow_p));
14113 strict_overflow_p);
14116 }
14118 /* We don't know sign of `t', so be conservative and return false. */
14120 }
14122 /* Return true if T is known to be non-negative. If the return
14123 value is based on the assumption that signed overflow is undefined,
14124 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14125 *STRICT_OVERFLOW_P. */
14127 bool
14129 {
14134 {
14146 strict_overflow_p)
14148 strict_overflow_p));
14152 }
14153 /* We don't know sign of `t', so be conservative and return false. */
14155 }
14157 /* Return true if T is known to be non-negative. If the return
14158 value is based on the assumption that signed overflow is undefined,
14159 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14160 *STRICT_OVERFLOW_P. */
14162 bool
14165 {
14168 {
14186 /* Always true. */
14190 /* sqrt(-0.0) is -0.0. */
14194 strict_overflow_p);
14227 /* True if the 1st argument is nonnegative. */
14229 strict_overflow_p);
14232 /* True if the 1st OR 2nd arguments are nonnegative. */
14234 strict_overflow_p)
14236 strict_overflow_p)));
14239 /* True if the 1st AND 2nd arguments are nonnegative. */
14241 strict_overflow_p)
14243 strict_overflow_p)));
14246 /* True if the 2nd argument is nonnegative. */
14248 strict_overflow_p);
14251 /* True if the 1st argument is nonnegative or the second
14252 argument is an even integer. */
14257 strict_overflow_p);
14260 /* True if the 1st argument is nonnegative or the second
14261 argument is an even integer valued real. */
14263 {
14264 REAL_VALUE_TYPE c;
14265 HOST_WIDE_INT n;
14270 {
14271 REAL_VALUE_TYPE cint;
14276 }
14277 }
14279 strict_overflow_p);
14283 }
14285 type);
14286 }
14288 /* Return true if T is known to be non-negative. If the return
14289 value is based on the assumption that signed overflow is undefined,
14290 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14291 *STRICT_OVERFLOW_P. */
14293 bool
14295 {
14301 {
14303 {
14307 /* If the initializer is non-void, then it's a normal expression
14308 that will be assigned to the slot. */
14312 /* Otherwise, the initializer sets the slot in some way. One common
14313 way is an assignment statement at the end of the initializer. */
14315 {
14323 else
14325 }
14329 strict_overflow_p);
14332 }
14335 {
14341 arg0,
14342 arg1,
14343 strict_overflow_p);
14344 }
14348 strict_overflow_p);
14351 strict_overflow_p);
14354 strict_overflow_p);
14359 }
14361 /* We don't know sign of `t', so be conservative and return false. */
14363 }
14365 /* Return true if T is known to be non-negative. If the return
14366 value is based on the assumption that signed overflow is undefined,
14367 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14368 *STRICT_OVERFLOW_P. */
14370 bool
14372 {
14379 {
14386 strict_overflow_p);
14392 strict_overflow_p);
14401 }
14404 {
14412 strict_overflow_p);
14417 strict_overflow_p);
14432 }
14433 }
14435 /* Return true if `t' is known to be non-negative. Handle warnings
14436 about undefined signed overflow. */
14438 bool
14440 {
14447 "determining that expression is always "
14449 WARN_STRICT_OVERFLOW_MISC);
14451 }
14454 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14455 For floating point we further ensure that T is not denormal.
14456 Similar logic is present in nonzero_address in rtlanal.h.
14458 If the return value is based on the assumption that signed overflow
14459 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14460 change *STRICT_OVERFLOW_P. */
14462 bool
14465 {
14467 {
14470 strict_overflow_p);
14473 {
14479 strict_overflow_p));
14480 }
14485 strict_overflow_p);
14489 }
14492 }
14494 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14495 For floating point we further ensure that T is not denormal.
14496 Similar logic is present in nonzero_address in rtlanal.h.
14498 If the return value is based on the assumption that signed overflow
14499 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14500 change *STRICT_OVERFLOW_P. */
14502 bool
14504 tree type,
14505 tree op0,
14507 {
14510 {
14514 {
14515 /* With the presence of negative values it is hard
14516 to say something. */
14523 /* One of operands must be positive and the other non-negative. */
14524 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14525 overflows, on a twos-complement machine the sum of two
14526 nonnegative numbers can never be zero. */
14528 strict_overflow_p)
14530 strict_overflow_p));
14531 }
14536 {
14538 strict_overflow_p)
14540 strict_overflow_p))
14541 {
14544 }
14545 }
14554 {
14557 }
14564 {
14568 /* When both operands are nonzero, then MAX must be too. */
14570 strict_overflow_p))
14573 /* MAX where operand 0 is positive is positive. */
14575 strict_overflow_p);
14576 }
14577 /* MAX where operand 1 is positive is positive. */
14582 {
14586 }
14591 strict_overflow_p)
14593 strict_overflow_p));
14597 }
14600 }
14602 /* Return true when T is an address and is known to be nonzero.
14603 For floating point we further ensure that T is not denormal.
14604 Similar logic is present in nonzero_address in rtlanal.h.
14606 If the return value is based on the assumption that signed overflow
14607 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14608 change *STRICT_OVERFLOW_P. */
14610 bool
14612 {
14615 {
14620 {
14626 /* Weak declarations may link to NULL. */
14630 /* Constants are never weak. */
14635 }
14643 {
14647 }
14652 }
14654 }
14656 /* Return true when T is an address and is known to be nonzero.
14657 For floating point we further ensure that T is not denormal.
14658 Similar logic is present in nonzero_address in rtlanal.h.
14660 If the return value is based on the assumption that signed overflow
14661 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14662 change *STRICT_OVERFLOW_P. */
14664 bool
14666 {
14670 /* Doing something useful for floating point would need more work. */
14676 {
14679 strict_overflow_p);
14685 strict_overflow_p);
14693 }
14696 {
14699 strict_overflow_p);
14707 strict_overflow_p);
14724 strict_overflow_p);
14728 strict_overflow_p);
14735 }
14737 }
14739 /* Return true when T is an address and is known to be nonzero.
14740 Handle warnings about undefined signed overflow. */
14742 bool
14744 {
14751 "determining that expression is always "
14753 WARN_STRICT_OVERFLOW_MISC);
14755 }
14757 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14758 attempt to fold the expression to a constant without modifying TYPE,
14759 OP0 or OP1.
14761 If the expression could be simplified to a constant, then return
14762 the constant. If the expression would not be simplified to a
14763 constant, then return NULL_TREE. */
14765 tree
14767 {
14770 }
14772 /* Given the components of a unary expression CODE, TYPE and OP0,
14773 attempt to fold the expression to a constant without modifying
14774 TYPE or OP0.
14776 If the expression could be simplified to a constant, then return
14777 the constant. If the expression would not be simplified to a
14778 constant, then return NULL_TREE. */
14780 tree
14782 {
14785 }
14787 /* If EXP represents referencing an element in a constant string
14788 (either via pointer arithmetic or array indexing), return the
14789 tree representing the value accessed, otherwise return NULL. */
14791 tree
14793 {
14797 {
14799 tree index;
14800 tree string;
14804 else
14805 {
14809 /* Optimize the special-case of a zero lower bound.
14811 We convert the low_bound to sizetype to avoid some problems
14812 with constant folding. (E.g. suppose the lower bound is 1,
14813 and its mode is QI. Without the conversion,l (ARRAY
14814 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14815 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
14820 }
14833 }
14835 }
14837 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14838 an integer constant, real, or fixed-point constant.
14840 TYPE is the type of the result. */
14842 static tree
14844 {
14848 {
14850 {
14852 HOST_WIDE_INT high;
14860 }
14867 {
14868 FIXED_VALUE_TYPE f;
14873 /* Propagate overflow flags. */
14875 {
14878 }
14882 }
14886 }
14889 }
14891 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14892 an integer constant or real constant.
14894 TYPE is the type of the result. */
14896 tree
14898 {
14902 {
14904 /* If the value is unsigned, then the absolute value is
14905 the same as the ordinary value. */
14908 /* Similarly, if the value is non-negative. */
14911 /* If the value is negative, then the absolute value is
14912 its negation. */
14913 else
14914 {
14916 HOST_WIDE_INT high;
14922 }
14928 else
14934 }
14937 }
14939 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14940 constant. TYPE is the type of the result. */
14942 static tree
14944 {
14954 }
14956 /* Given CODE, a relational operator, the target type, TYPE and two
14957 constant operands OP0 and OP1, return the result of the
14958 relational operation. If the result is not a compile time
14959 constant, then return NULL_TREE. */
14961 static tree
14963 {
14966 /* From here on, the only cases we handle are when the result is
14967 known to be a constant. */
14970 {
14974 /* Handle the cases where either operand is a NaN. */
14976 {
14978 {
15006 }
15009 }
15012 }
15015 {
15019 }
15021 /* Handle equality/inequality of complex constants. */
15023 {
15034 else
15036 }
15038 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15040 To compute GT, swap the arguments and do LT.
15041 To compute GE, do LT and invert the result.
15042 To compute LE, swap the arguments, do LT and invert the result.
15043 To compute NE, do EQ and invert the result.
15045 Therefore, the code below must handle only EQ and LT. */
15048 {
15053 }
15055 /* Note that it is safe to invert for real values here because we
15056 have already handled the one case that it matters. */
15060 {
15063 }
15065 /* Compute a result for LT or EQ if args permit;
15066 Otherwise return T. */
15068 {
15073 else
15075 }
15076 else
15082 }
15084 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15085 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15086 itself. */
15088 tree
15090 {
15091 /* If the expression does not have side effects then we don't have to wrap
15092 it with a cleanup point expression. */
15096 /* If the expression is a return, check to see if the expression inside the
15097 return has no side effects or the right hand side of the modify expression
15098 inside the return. If either don't have side effects set we don't need to
15099 wrap the expression in a cleanup point expression. Note we don't check the
15100 left hand side of the modify because it should always be a return decl. */
15102 {
15109 }
15112 }
15114 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15115 of an indirection through OP0, or NULL_TREE if no simplification is
15116 possible. */
15118 tree
15120 {
15122 tree subtype;
15130 {
15133 /* *&CONST_DECL -> to the value of the const decl. */
15136 /* *&p => p; make sure to handle *&"str"[cst] here. */
15138 {
15142 else
15144 }
15145 /* *(foo *)&fooarray => fooarray[0] */
15148 {
15154 }
15155 /* *(foo *)&complexfoo => __real__ complexfoo */
15159 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15162 {
15166 }
15167 }
15169 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15172 {
15175 tree op00type;
15182 {
15193 }
15194 }
15197 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15200 {
15203 tree op00type;
15210 {
15214 }
15215 }
15217 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15220 {
15221 tree type_domain;
15228 }
15231 }
15233 /* Builds an expression for an indirection through T, simplifying some
15234 cases. */
15236 tree
15238 {
15244 else
15246 }
15248 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15250 tree
15252 {
15257 else
15259 }
15261 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15262 whose result is ignored. The type of the returned tree need not be
15263 the same as the original expression. */
15265 tree
15267 {
15273 {
15284 else
15290 {
15306 }
15311 }
15312 }
15314 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15315 This can only be applied to objects of a sizetype. */
15317 tree
15319 {
15326 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15327 have to do anything. Only do this when we are not given a const,
15328 because in that case, this check is more expensive than just
15329 doing it. */
15331 {
15336 }
15338 /* If divisor is a power of two, simplify this to bit manipulation. */
15340 {
15342 {
15355 {
15356 high++;
15359 }
15363 }
15364 else
15365 {
15366 tree t;
15372 }
15373 }
15374 else
15375 {
15380 }
15383 }
15385 /* Likewise, but round down. */
15387 tree
15389 {
15396 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15397 have to do anything. Only do this when we are not given a const,
15398 because in that case, this check is more expensive than just
15399 doing it. */
15401 {
15406 }
15408 /* If divisor is a power of two, simplify this to bit manipulation. */
15410 {
15411 tree t;
15415 }
15416 else
15417 {
15422 }
15425 }
15427 /* Returns the pointer to the base of the object addressed by EXP and
15428 extracts the information about the offset of the access, storing it
15429 to PBITPOS and POFFSET. */
15431 static tree
15434 {
15435 tree core;
15438 HOST_WIDE_INT bitsize;
15441 {
15446 }
15447 else
15448 {
15452 }
15455 }
15457 /* Returns true if addresses of E1 and E2 differ by a constant, false
15458 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15460 bool
15462 {
15476 {
15486 }
15488 {
15489 /* If only one of the offsets is non-constant, the difference cannot
15490 be a constant. */
15492 }
15493 else
15498 }
15500 /* Simplify the floating point expression EXP when the sign of the
15501 result is not significant. Return NULL_TREE if no simplification
15502 is possible. */
15504 tree
15506 {
15510 {
15545 {
15548 {
15550 /* Strip copysign function call, return the 1st argument. */
15556 /* Strip sign ops from the argument of "odd" math functions. */
15558 {
15562 }
15564 }
15565 }
15570 }
15572 }