| blob | 0ce122a15545b3f57362ce781703d55bd6099460 |
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 };
125 tree);
146 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
147 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
148 and SUM1. Then this yields nonzero if overflow occurred during the
149 addition.
151 Overflow occurs if A and B have the same sign, but A and SUM differ in
152 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
153 sign. */
154 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
155 \f
156 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
157 We do that by representing the two-word integer in 4 words, with only
158 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
159 number. The value of the word is LOWPART + HIGHPART * BASE. */
161 #define LOWPART(x) \
162 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
163 #define HIGHPART(x) \
164 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
165 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
167 /* Unpack a two-word integer into 4 words.
168 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
169 WORDS points to the array of HOST_WIDE_INTs. */
171 static void
173 {
178 }
180 /* Pack an array of 4 words into a two-word integer.
181 WORDS points to the array of words.
182 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
184 static void
187 {
190 }
191 \f
192 /* Force the double-word integer L1, H1 to be within the range of the
193 integer type TYPE. Stores the properly truncated and sign-extended
194 double-word integer in *LV, *HV. Returns true if the operation
195 overflows, that is, argument and result are different. */
197 int
200 {
209 else
212 /* Size types *are* sign extended. */
217 /* First clear all bits that are beyond the type's precision. */
219 ;
222 else
223 {
227 }
229 /* Then do sign extension if necessary. */
235 {
236 /* Sign extend top half? */
240 }
242 {
245 }
246 else
247 {
248 /* Sign extend bottom half? */
250 {
253 }
254 }
259 /* If the value didn't fit, signal overflow. */
261 }
263 /* We force the double-int HIGH:LOW to the range of the type TYPE by
264 sign or zero extending it.
265 OVERFLOWABLE indicates if we are interested
266 in overflow of the value, when >0 we are only interested in signed
267 overflow, for <0 we are interested in any overflow. OVERFLOWED
268 indicates whether overflow has already occurred. CONST_OVERFLOWED
269 indicates whether constant overflow has already occurred. We force
270 T's value to be within range of T's type (by setting to 0 or 1 all
271 the bits outside the type's range). We set TREE_OVERFLOWED if,
272 OVERFLOWED is nonzero,
273 or OVERFLOWABLE is >0 and signed overflow occurs
274 or OVERFLOWABLE is <0 and any overflow occurs
275 We return a new tree node for the extended double-int. The node
276 is shared if no overflow flags are set. */
278 tree
282 {
286 /* Size types *are* sign extended. */
293 /* If we need to set overflow flags, return a new unshared node. */
295 {
299 {
306 }
307 }
309 /* Else build a shared node. */
311 }
312 \f
313 /* Add two doubleword integers with doubleword result.
314 Return nonzero if the operation overflows according to UNSIGNED_P.
315 Each argument is given as two `HOST_WIDE_INT' pieces.
316 One argument is L1 and H1; the other, L2 and H2.
317 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
319 int
324 {
326 HOST_WIDE_INT h;
336 else
338 }
340 /* Negate a doubleword integer with doubleword result.
341 Return nonzero if the operation overflows, assuming it's signed.
342 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
343 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
345 int
348 {
350 {
354 }
355 else
356 {
360 }
361 }
362 \f
363 /* Multiply two doubleword integers with doubleword result.
364 Return nonzero if the operation overflows according to UNSIGNED_P.
365 Each argument is given as two `HOST_WIDE_INT' pieces.
366 One argument is L1 and H1; the other, L2 and H2.
367 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
369 int
374 {
389 {
392 {
394 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
396 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
400 }
402 }
407 /* Unsigned overflow is immediate. */
411 /* Check for signed overflow by calculating the signed representation of the
412 top half of the result; it should agree with the low half's sign bit. */
414 {
417 }
419 {
422 }
424 }
425 \f
426 /* Shift the doubleword integer in L1, H1 left by COUNT places
427 keeping only PREC bits of result.
428 Shift right if COUNT is negative.
429 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
430 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
432 void
436 {
440 {
443 }
449 {
450 /* Shifting by the host word size is undefined according to the
451 ANSI standard, so we must handle this as a special case. */
454 }
456 {
459 }
460 else
461 {
465 }
467 /* Sign extend all bits that are beyond the precision. */
475 ;
477 {
480 }
481 else
482 {
486 }
487 }
489 /* Shift the doubleword integer in L1, H1 right by COUNT places
490 keeping only PREC bits of result. COUNT must be positive.
491 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
492 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
494 void
499 {
502 signmask = (arith
510 {
511 /* Shifting by the host word size is undefined according to the
512 ANSI standard, so we must handle this as a special case. */
515 }
517 {
520 }
521 else
522 {
526 }
528 /* Zero / sign extend all bits that are beyond the precision. */
531 {
534 }
536 ;
538 {
541 }
542 else
543 {
547 }
548 }
549 \f
550 /* Rotate the doubleword integer in L1, H1 left by COUNT places
551 keeping only PREC bits of result.
552 Rotate right if COUNT is negative.
553 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
555 void
559 {
571 }
573 /* Rotate the doubleword integer in L1, H1 left by COUNT places
574 keeping only PREC bits of result. COUNT must be positive.
575 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
577 void
581 {
593 }
594 \f
595 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
596 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
597 CODE is a tree code for a kind of division, one of
598 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
599 or EXACT_DIV_EXPR
600 It controls how the quotient is rounded to an integer.
601 Return nonzero if the operation overflows.
602 UNS nonzero says do unsigned division. */
604 int
607 HOST_WIDE_INT hnum_orig,
609 HOST_WIDE_INT hden_orig,
613 {
629 /* Calculate quotient sign and convert operands to unsigned. */
631 {
633 {
635 /* (minimum integer) / (-1) is the only overflow case. */
639 }
641 {
644 }
645 }
650 /* This unsigned division rounds toward zero. */
653 }
657 /* hden != 0 already checked. */
662 }
672 /* Special code for when the divisor < BASE. */
674 {
675 /* hnum != 0 already checked. */
677 {
681 }
682 }
683 else
684 {
685 /* Full double precision division,
686 with thanks to Don Knuth's "Seminumerical Algorithms". */
690 /* Find the highest nonzero divisor digit. */
693 {
696 }
698 /* Insure that the first digit of the divisor is at least BASE/2.
699 This is required by the quotient digit estimation algorithm. */
706 {
710 }
715 {
720 }
721 }
725 /* Main loop */
727 {
728 /* Guess the next quotient digit, quo_est, by dividing the first
729 two remaining dividend digits by the high order quotient digit.
730 quo_est is never low and is at most 2 high. */
737 else
740 /* Refine quo_est so it's usually correct, and at most one high. */
745 quo_est--;
747 /* Try QUO_EST as the quotient digit, by multiplying the
748 divisor by QUO_EST and subtracting from the remaining dividend.
749 Keep in mind that QUO_EST is the I - 1st digit. */
753 {
759 }
761 /* If quo_est was high by one, then num[i] went negative and
762 we need to correct things. */
764 {
765 quo_est--;
768 {
772 }
775 }
777 /* Store the quotient digit. */
779 }
780 }
784 finish_up:
785 /* If result is negative, make it so. */
789 /* Compute trial remainder: rem = num - (quo * den) */
795 {
804 {
805 /* quo = quo - 1; */
808 }
809 else
816 {
819 }
820 else
826 {
832 /* Get absolute values. */
838 /* If (2 * abs (lrem) >= abs (lden)), adjust the quotient. */
847 {
849 /* quo = quo - 1; */
852 else
853 /* quo = quo + 1; */
856 }
857 else
859 }
864 }
866 /* Compute true remainder: rem = num - (quo * den) */
871 }
873 /* If ARG2 divides ARG1 with zero remainder, carries out the division
874 of type CODE and returns the quotient.
875 Otherwise returns NULL_TREE. */
877 static tree
879 {
889 /* &obj[0] + -128 really should be compiled as &obj[-8] rather than
890 &obj[some_exotic_number]. */
892 {
896 type);
897 }
898 else
909 }
910 \f
911 /* This is nonzero if we should defer warnings about undefined
912 overflow. This facility exists because these warnings are a
913 special case. The code to estimate loop iterations does not want
914 to issue any warnings, since it works with expressions which do not
915 occur in user code. Various bits of cleanup code call fold(), but
916 only use the result if it has certain characteristics (e.g., is a
917 constant); that code only wants to issue a warning if the result is
918 used. */
922 /* If a warning about undefined overflow is deferred, this is the
923 warning. Note that this may cause us to turn two warnings into
924 one, but that is fine since it is sufficient to only give one
925 warning per expression. */
929 /* If a warning about undefined overflow is deferred, this is the
930 level at which the warning should be emitted. */
934 /* Start deferring overflow warnings. We could use a stack here to
935 permit nested calls, but at present it is not necessary. */
937 void
939 {
941 }
943 /* Stop deferring overflow warnings. If there is a pending warning,
944 and ISSUE is true, then issue the warning if appropriate. STMT is
945 the statement with which the warning should be associated (used for
946 location information); STMT may be NULL. CODE is the level of the
947 warning--a warn_strict_overflow_code value. This function will use
948 the smaller of CODE and the deferred code when deciding whether to
949 issue the warning. CODE may be zero to mean to always use the
950 deferred code. */
952 void
954 {
956 location_t locus;
961 {
967 }
978 /* Use the smallest code level when deciding to issue the
979 warning. */
988 else
991 }
993 /* Stop deferring overflow warnings, ignoring any deferred
994 warnings. */
996 void
998 {
1000 }
1002 /* Whether we are deferring overflow warnings. */
1004 bool
1006 {
1008 }
1010 /* This is called when we fold something based on the fact that signed
1011 overflow is undefined. */
1013 static void
1015 {
1017 {
1020 {
1023 }
1024 }
1027 }
1028 \f
1029 /* Return true if the built-in mathematical function specified by CODE
1030 is odd, i.e. -f(x) == f(-x). */
1032 static bool
1034 {
1036 {
1070 }
1072 }
1074 /* Check whether we may negate an integer constant T without causing
1075 overflow. */
1077 bool
1079 {
1082 tree type;
1092 {
1097 }
1098 else
1103 }
1105 /* Determine whether an expression T can be cheaply negated using
1106 the function negate_expr without introducing undefined overflow. */
1108 static bool
1110 {
1111 tree type;
1120 {
1125 /* Check that -CST will not overflow type. */
1151 /* -(A + B) -> (-B) - A. */
1156 /* -(A + B) -> (-A) - B. */
1160 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
1170 /* Fall through. */
1183 /* In general we can't negate A / B, because if A is INT_MIN and
1184 B is 1, we may turn this into INT_MIN / -1 which is undefined
1185 and actually traps on some architectures. But if overflow is
1186 undefined, we can negate, because - (INT_MIN / 1) is an
1187 overflow. */
1195 /* Negate -((double)float) as (double)(-float). */
1197 {
1201 }
1205 /* Negate -f(x) as f(-x). */
1211 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1213 {
1219 }
1224 }
1226 }
1228 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
1229 simplification is possible.
1230 If negate_expr_p would return true for T, NULL_TREE will never be
1231 returned. */
1233 static tree
1235 {
1237 tree tem;
1240 {
1241 /* Convert - (~A) to A + 1. */
1257 /* Two's complement FP formats, such as c4x, may overflow. */
1267 {
1276 }
1298 {
1299 /* -(A + B) -> (-B) - A. */
1303 {
1307 }
1309 /* -(A + B) -> (-A) - B. */
1311 {
1315 }
1316 }
1320 /* - (A - B) -> B - A */
1332 /* Fall through. */
1336 {
1345 }
1353 /* In general we can't negate A / B, because if A is INT_MIN and
1354 B is 1, we may turn this into INT_MIN / -1 which is undefined
1355 and actually traps on some architectures. But if overflow is
1356 undefined, we can negate, because - (INT_MIN / 1) is an
1357 overflow. */
1359 {
1364 {
1371 }
1374 {
1381 }
1382 }
1386 /* Convert -((double)float) into (double)(-float). */
1388 {
1392 }
1396 /* Negate -f(x) as f(-x). */
1399 {
1405 }
1409 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1411 {
1416 {
1423 }
1424 }
1429 }
1432 }
1434 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
1435 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
1436 return NULL_TREE. */
1438 static tree
1440 {
1453 }
1454 \f
1455 /* Split a tree IN into a constant, literal and variable parts that could be
1456 combined with CODE to make IN. "constant" means an expression with
1457 TREE_CONSTANT but that isn't an actual constant. CODE must be a
1458 commutative arithmetic operation. Store the constant part into *CONP,
1459 the literal in *LITP and return the variable part. If a part isn't
1460 present, set it to null. If the tree does not decompose in this way,
1461 return the entire tree as the variable part and the other parts as null.
1463 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
1464 case, we negate an operand that was subtracted. Except if it is a
1465 literal for which we use *MINUS_LITP instead.
1467 If NEGATE_P is true, we are negating all of IN, again except a literal
1468 for which we use *MINUS_LITP instead.
1470 If IN is itself a literal or constant, return it as appropriate.
1472 Note that we do not guarantee that any of the three values will be the
1473 same type as IN, but they will have the same signedness and mode. */
1475 static tree
1478 {
1485 /* Strip any conversions that don't change the machine mode or signedness. */
1494 /* We can associate addition and subtraction together (even
1495 though the C standard doesn't say so) for integers because
1496 the value is not affected. For reals, the value might be
1497 affected, so we can't. */
1500 {
1506 /* First see if either of the operands is a literal, then a constant. */
1519 /* If we haven't dealt with either operand, this is not a case we can
1520 decompose. Otherwise, VAR is either of the ones remaining, if any. */
1525 else
1528 /* Now do any needed negations. */
1535 }
1538 else
1542 {
1549 }
1552 }
1554 /* Re-associate trees split by the above function. T1 and T2 are either
1555 expressions to associate or null. Return the new expression, if any. If
1556 we build an operation, do it in TYPE and with CODE. */
1558 static tree
1560 {
1566 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
1567 try to fold this since we will have infinite recursion. But do
1568 deal with any NEGATE_EXPRs. */
1571 {
1573 {
1582 }
1584 {
1587 }
1591 }
1595 }
1596 \f
1597 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1598 for use in int_const_binop, size_binop and size_diffop. */
1600 static bool
1602 {
1609 {
1618 }
1623 }
1626 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1627 to produce a new constant. Return NULL_TREE if we don't know how
1628 to evaluate CODE at compile-time.
1630 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1632 tree
1634 {
1638 HOST_WIDE_INT hi;
1640 HOST_WIDE_INT garbageh;
1641 tree t;
1644 int is_sizetype
1654 {
1670 /* It's unclear from the C standard whether shifts can overflow.
1671 The following code ignores overflow; perhaps a C standard
1672 interpretation ruling is needed. */
1701 /* This is a shortcut for a common special case. */
1706 {
1712 }
1714 /* ... fall through ... */
1720 {
1723 }
1726 {
1729 }
1736 /* This is a shortcut for a common special case. */
1741 {
1746 }
1748 /* ... fall through ... */
1766 else
1772 else
1778 }
1781 {
1784 /* Propagate overflow flags ourselves. */
1787 {
1790 }
1791 }
1792 else
1798 }
1800 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1801 constant. We assume ARG1 and ARG2 have the same data type, or at least
1802 are the same kind of constant and the same machine mode. Return zero if
1803 combining the constants is not allowed in the current operating mode.
1805 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1807 static tree
1809 {
1810 /* Sanity check for the recursive cases. */
1821 {
1823 REAL_VALUE_TYPE d1;
1824 REAL_VALUE_TYPE d2;
1825 REAL_VALUE_TYPE value;
1826 REAL_VALUE_TYPE result;
1830 /* The following codes are handled by real_arithmetic. */
1832 {
1843 }
1851 /* Don't perform operation if we honor signaling NaNs and
1852 either operand is a NaN. */
1857 /* Don't perform operation if it would raise a division
1858 by zero exception. */
1864 /* If either operand is a NaN, just return it. Otherwise, set up
1865 for floating-point trap; we return an overflow. */
1874 /* Don't constant fold this floating point operation if
1875 the result has overflowed and flag_trapping_math. */
1883 /* Don't constant fold this floating point operation if the
1884 result may dependent upon the run-time rounding mode and
1885 flag_rounding_math is set, or if GCC's software emulation
1886 is unable to accurately represent the result. */
1896 }
1899 {
1900 FIXED_VALUE_TYPE f1;
1901 FIXED_VALUE_TYPE f2;
1902 FIXED_VALUE_TYPE result;
1907 /* The following codes are handled by fixed_arithmetic. */
1909 {
1926 }
1933 /* Propagate overflow flags. */
1935 {
1938 }
1942 }
1945 {
1954 {
1965 notrunc);
1969 notrunc);
1973 {
1974 tree magsquared
1978 notrunc);
1979 tree t1
1983 notrunc);
1984 tree t2
1988 notrunc);
1995 }
2000 }
2004 }
2007 }
2009 /* Create a size type INT_CST node with NUMBER sign extended. KIND
2010 indicates which particular sizetype to create. */
2012 tree
2014 {
2016 }
2017 \f
2018 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2019 is a tree code. The type of the result is taken from the operands.
2020 Both must be equivalent integer types, ala int_binop_types_match_p.
2021 If the operands are constant, so is the result. */
2023 tree
2025 {
2034 /* Handle the special case of two integer constants faster. */
2036 {
2037 /* And some specific cases even faster than that. */
2039 {
2044 }
2046 {
2049 }
2051 {
2054 }
2056 /* Handle general case of two integer constants. */
2058 }
2061 }
2063 /* Given two values, either both of sizetype or both of bitsizetype,
2064 compute the difference between the two values. Return the value
2065 in signed type corresponding to the type of the operands. */
2067 tree
2069 {
2071 tree ctype;
2076 /* If the type is already signed, just do the simple thing. */
2084 else
2087 /* If either operand is not a constant, do the conversions to the signed
2088 type and subtract. The hardware will do the right thing with any
2089 overflow in the subtraction. */
2094 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2095 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2096 overflow) and negate (which can't either). Special-case a result
2097 of zero while we're here. */
2102 else
2106 }
2107 \f
2108 /* A subroutine of fold_convert_const handling conversions of an
2109 INTEGER_CST to another integer type. */
2111 static tree
2113 {
2114 tree t;
2116 /* Given an integer constant, make new constant with new type,
2117 appropriately sign-extended or truncated. */
2120 /* Don't set the overflow when
2121 converting from a pointer, */
2123 /* or to a sizetype with same signedness
2124 and the precision is unchanged.
2125 ??? sizetype is always sign-extended,
2126 but its signedness depends on the
2127 frontend. Thus we see spurious overflows
2128 here if we do not check this. */
2143 }
2145 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2146 to an integer type. */
2148 static tree
2150 {
2152 tree t;
2154 /* The following code implements the floating point to integer
2155 conversion rules required by the Java Language Specification,
2156 that IEEE NaNs are mapped to zero and values that overflow
2157 the target precision saturate, i.e. values greater than
2158 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2159 are mapped to INT_MIN. These semantics are allowed by the
2160 C and C++ standards that simply state that the behavior of
2161 FP-to-integer conversion is unspecified upon overflow. */
2164 REAL_VALUE_TYPE r;
2168 {
2175 }
2177 /* If R is NaN, return zero and show we have an overflow. */
2179 {
2183 }
2185 /* See if R is less than the lower bound or greater than the
2186 upper bound. */
2189 {
2193 {
2197 }
2198 }
2201 {
2204 {
2207 {
2211 }
2212 }
2213 }
2221 }
2223 /* A subroutine of fold_convert_const handling conversions of a
2224 FIXED_CST to an integer type. */
2226 static tree
2228 {
2229 tree t;
2233 /* Right shift FIXED_CST to temp by fbit. */
2237 {
2242 /* Left shift temp to temp_trunc by fbit. */
2247 }
2248 else
2249 {
2254 }
2256 /* If FIXED_CST is negative, we need to round the value toward 0.
2257 By checking if the fractional bits are not zero to add 1 to temp. */
2260 {
2261 double_int one;
2265 }
2267 /* Given a fixed-point constant, make new constant with new type,
2268 appropriately sign-extended or truncated. */
2276 }
2278 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2279 to another floating point type. */
2281 static tree
2283 {
2284 REAL_VALUE_TYPE value;
2285 tree t;
2292 }
2294 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2295 to a floating point type. */
2297 static tree
2299 {
2300 REAL_VALUE_TYPE value;
2301 tree t;
2310 }
2312 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2313 to another fixed-point type. */
2315 static tree
2317 {
2318 FIXED_VALUE_TYPE value;
2319 tree t;
2326 /* Propagate overflow flags. */
2328 {
2331 }
2335 }
2337 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2338 to a fixed-point type. */
2340 static tree
2342 {
2343 FIXED_VALUE_TYPE value;
2344 tree t;
2353 /* Propagate overflow flags. */
2355 {
2358 }
2362 }
2364 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2365 to a fixed-point type. */
2367 static tree
2369 {
2370 FIXED_VALUE_TYPE value;
2371 tree t;
2379 /* Propagate overflow flags. */
2381 {
2384 }
2388 }
2390 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2391 type TYPE. If no simplification can be done return NULL_TREE. */
2393 static tree
2395 {
2401 {
2408 }
2410 {
2417 }
2419 {
2426 }
2428 }
2430 /* Construct a vector of zero elements of vector type TYPE. */
2432 static tree
2434 {
2445 }
2447 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2449 bool
2451 {
2466 {
2485 }
2486 }
2488 /* Convert expression ARG to type TYPE. Used by the middle-end for
2489 simple conversions in preference to calling the front-end's convert. */
2491 tree
2493 {
2495 tree tem;
2509 {
2514 {
2518 }
2523 {
2526 }
2533 {
2537 }
2539 {
2543 }
2545 {
2549 }
2552 {
2570 }
2575 {
2579 }
2582 {
2596 }
2600 {
2610 {
2614 {
2618 }
2626 }
2630 }
2648 }
2649 }
2650 \f
2651 /* Return false if expr can be assumed not to be an lvalue, true
2652 otherwise. */
2654 static bool
2656 {
2657 /* We only need to wrap lvalue tree codes. */
2659 {
2693 /* Assume the worst for front-end tree codes. */
2697 }
2700 }
2702 /* Return an expr equal to X but certainly not valid as an lvalue. */
2704 tree
2706 {
2707 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2708 us. */
2715 }
2717 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2718 Zero means allow extended lvalues. */
2722 /* When pedantic, return an expr equal to X but certainly not valid as a
2723 pedantic lvalue. Otherwise, return X. */
2725 static tree
2727 {
2730 else
2732 }
2733 \f
2734 /* Given a tree comparison code, return the code that is the logical inverse
2735 of the given code. It is not safe to do this for floating-point
2736 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2737 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2739 enum tree_code
2741 {
2746 {
2777 }
2778 }
2780 /* Similar, but return the comparison that results if the operands are
2781 swapped. This is safe for floating-point. */
2783 enum tree_code
2785 {
2787 {
2813 }
2814 }
2817 /* Convert a comparison tree code from an enum tree_code representation
2818 into a compcode bit-based encoding. This function is the inverse of
2819 compcode_to_comparison. */
2821 static enum comparison_code
2823 {
2825 {
2856 }
2857 }
2859 /* Convert a compcode bit-based encoding of a comparison operator back
2860 to GCC's enum tree_code representation. This function is the
2861 inverse of comparison_to_compcode. */
2863 static enum tree_code
2865 {
2867 {
2898 }
2899 }
2901 /* Return a tree for the comparison which is the combination of
2902 doing the AND or OR (depending on CODE) of the two operations LCODE
2903 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2904 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2905 if this makes the transformation invalid. */
2907 tree
2911 {
2918 {
2929 }
2932 {
2933 /* Eliminate unordered comparisons, as well as LTGT and ORD
2934 which are not used unless the mode has NaNs. */
2940 }
2942 {
2943 /* Check that the original operation and the optimized ones will trap
2944 under the same condition. */
2955 /* In a short-circuited boolean expression the LHS might be
2956 such that the RHS, if evaluated, will never trap. For
2957 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2958 if neither x nor y is NaN. (This is a mixed blessing: for
2959 example, the expression above will never trap, hence
2960 optimizing it to x < y would be invalid). */
2965 /* If the comparison was short-circuited, and only the RHS
2966 trapped, we may now generate a spurious trap. */
2971 /* If we changed the conditions that cause a trap, we lose. */
2974 }
2980 else
2983 }
2985 /* Return nonzero if CODE is a tree code that represents a truth value. */
2987 static int
2989 {
2994 }
2995 \f
2996 /* Return nonzero if two operands (typically of the same tree node)
2997 are necessarily equal. If either argument has side-effects this
2998 function returns zero. FLAGS modifies behavior as follows:
3000 If OEP_ONLY_CONST is set, only return nonzero for constants.
3001 This function tests whether the operands are indistinguishable;
3002 it does not test whether they are equal using C's == operation.
3003 The distinction is important for IEEE floating point, because
3004 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3005 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3007 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3008 even though it may hold multiple values during a function.
3009 This is because a GCC tree node guarantees that nothing else is
3010 executed between the evaluation of its "operands" (which may often
3011 be evaluated in arbitrary order). Hence if the operands themselves
3012 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3013 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3014 unset means assuming isochronic (or instantaneous) tree equivalence.
3015 Unless comparing arbitrary expression trees, such as from different
3016 statements, this flag can usually be left unset.
3018 If OEP_PURE_SAME is set, then pure functions with identical arguments
3019 are considered the same. It is used when the caller has other ways
3020 to ensure that global memory is unchanged in between. */
3022 int
3024 {
3025 /* If either is ERROR_MARK, they aren't equal. */
3029 /* Check equality of integer constants before bailing out due to
3030 precision differences. */
3034 /* If both types don't have the same signedness, then we can't consider
3035 them equal. We must check this before the STRIP_NOPS calls
3036 because they may change the signedness of the arguments. As pointers
3037 strictly don't have a signedness, require either two pointers or
3038 two non-pointers as well. */
3043 /* If both types don't have the same precision, then it is not safe
3044 to strip NOPs. */
3051 /* In case both args are comparisons but with different comparison
3052 code, try to swap the comparison operands of one arg to produce
3053 a match and compare that variant. */
3057 {
3065 }
3068 /* This is needed for conversions and for COMPONENT_REF.
3069 Might as well play it safe and always test this. */
3075 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3076 We don't care about side effects in that case because the SAVE_EXPR
3077 takes care of that for us. In all other cases, two expressions are
3078 equal if they have no side effects. If we have two identical
3079 expressions with side effects that should be treated the same due
3080 to the only side effects being identical SAVE_EXPR's, that will
3081 be detected in the recursive calls below. */
3087 /* Next handle constant cases, those for which we can return 1 even
3088 if ONLY_CONST is set. */
3091 {
3106 {
3107 /* If we do not distinguish between signed and unsigned zero,
3108 consider them equal. */
3111 }
3115 {
3121 {
3123 flags))
3127 }
3130 }
3134 flags)
3136 flags));
3149 }
3154 /* Define macros to test an operand from arg0 and arg1 for equality and a
3155 variant that allows null and views null as being different from any
3156 non-null value. In the latter case, if either is null, the both
3157 must be; otherwise, do the normal comparison. */
3158 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3159 TREE_OPERAND (arg1, N), flags)
3161 #define OP_SAME_WITH_NULL(N) \
3162 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3163 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3166 {
3168 /* Two conversions are equal only if signedness and modes match. */
3170 {
3171 CASE_CONVERT:
3179 }
3189 /* For commutative ops, allow the other order. */
3197 /* If either of the pointer (or reference) expressions we are
3198 dereferencing contain a side effect, these cannot be equal. */
3204 {
3214 /* Operands 2 and 3 may be null.
3215 Compare the array index by value if it is constant first as we
3216 may have different types but same value here. */
3225 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3226 may be NULL when we're called to compare MEM_EXPRs. */
3236 }
3240 {
3255 /* Otherwise take into account this is a commutative operation. */
3266 }
3270 {
3272 /* If the CALL_EXPRs call different functions, then they
3273 clearly can not be equal. */
3275 flags))
3278 {
3282 else
3286 }
3288 /* Now see if all the arguments are the same. */
3289 {
3300 /* If we get here and both argument lists are exhausted
3301 then the CALL_EXPRs are equal. */
3303 }
3306 }
3309 /* Consider __builtin_sqrt equal to sqrt. */
3317 }
3319 #undef OP_SAME
3320 #undef OP_SAME_WITH_NULL
3321 }
3322 \f
3323 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3324 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3326 When in doubt, return 0. */
3328 static int
3330 {
3342 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3343 and see if the inner values are the same. This removes any
3344 signedness comparison, which doesn't matter here. */
3351 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3352 actual comparison operand, ARG0.
3354 First throw away any conversions to wider types
3355 already present in the operands. */
3364 {
3367 /* Make sure shorter operand is extended the right way
3368 to match the longer operand. */
3374 }
3377 }
3378 \f
3379 /* See if ARG is an expression that is either a comparison or is performing
3380 arithmetic on comparisons. The comparisons must only be comparing
3381 two different values, which will be stored in *CVAL1 and *CVAL2; if
3382 they are nonzero it means that some operands have already been found.
3383 No variables may be used anywhere else in the expression except in the
3384 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3385 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3387 If this is true, return 1. Otherwise, return zero. */
3389 static int
3391 {
3395 /* We can handle some of the tcc_expression cases here. */
3405 {
3406 /* If we've already found a CVAL1 or CVAL2, this expression is
3407 two complex to handle. */
3413 }
3416 {
3439 /* First see if we can handle the first operand, then the second. For
3440 the second operand, we know *CVAL1 can't be zero. It must be that
3441 one side of the comparison is each of the values; test for the
3442 case where this isn't true by failing if the two operands
3443 are the same. */
3452 ;
3456 ;
3457 else
3461 ;
3465 ;
3466 else
3473 }
3474 }
3475 \f
3476 /* ARG is a tree that is known to contain just arithmetic operations and
3477 comparisons. Evaluate the operations in the tree substituting NEW0 for
3478 any occurrence of OLD0 as an operand of a comparison and likewise for
3479 NEW1 and OLD1. */
3481 static tree
3483 {
3488 /* We can handle some of the tcc_expression cases here. */
3496 {
3511 {
3528 }
3529 /* Fall through - ??? */
3532 {
3536 /* We need to check both for exact equality and tree equality. The
3537 former will be true if the operand has a side-effect. In that
3538 case, we know the operand occurred exactly once. */
3551 }
3555 }
3556 }
3557 \f
3558 /* Return a tree for the case when the result of an expression is RESULT
3559 converted to TYPE and OMITTED was previously an operand of the expression
3560 but is now not needed (e.g., we folded OMITTED * 0).
3562 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3563 the conversion of RESULT to TYPE. */
3565 tree
3567 {
3570 /* If the resulting operand is an empty statement, just return the omitted
3571 statement casted to void. */
3579 }
3581 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3583 static tree
3585 {
3588 /* If the resulting operand is an empty statement, just return the omitted
3589 statement casted to void. */
3597 }
3599 /* Return a tree for the case when the result of an expression is RESULT
3600 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3601 of the expression but are now not needed.
3603 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3604 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3605 evaluated before OMITTED2. Otherwise, if neither has side effects,
3606 just do the conversion of RESULT to TYPE. */
3608 tree
3610 {
3619 }
3621 \f
3622 /* Return a simplified tree node for the truth-negation of ARG. This
3623 never alters ARG itself. We assume that ARG is an operation that
3624 returns a truth value (0 or 1).
3626 FIXME: one would think we would fold the result, but it causes
3627 problems with the dominator optimizer. */
3629 tree
3631 {
3635 /* If this is a comparison, we can simply invert it, except for
3636 floating-point non-equality comparisons, in which case we just
3637 enclose a TRUTH_NOT_EXPR around what we have. */
3640 {
3643 && flag_trapping_math
3647 else
3648 {
3653 else
3656 }
3657 }
3660 {
3675 /* Here we can invert either operand. We invert the first operand
3676 unless the second operand is a TRUTH_NOT_EXPR in which case our
3677 result is the XOR of the first operand with the inside of the
3678 negation of the second operand. */
3683 else
3702 {
3705 /* A COND_EXPR may have a throw as one operand, which
3706 then has void type. Just leave void operands
3707 as they are. */
3713 }
3746 }
3749 }
3751 /* Return a simplified tree node for the truth-negation of ARG. This
3752 never alters ARG itself. We assume that ARG is an operation that
3753 returns a truth value (0 or 1).
3755 FIXME: one would think we would fold the result, but it causes
3756 problems with the dominator optimizer. */
3758 tree
3760 {
3761 tree tem;
3771 }
3773 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3774 operands are another bit-wise operation with a common input. If so,
3775 distribute the bit operations to save an operation and possibly two if
3776 constants are involved. For example, convert
3777 (A | B) & (A | C) into A | (B & C)
3778 Further simplification will occur if B and C are constants.
3780 If this optimization cannot be done, 0 will be returned. */
3782 static tree
3784 {
3785 tree common;
3795 {
3799 }
3801 {
3805 }
3807 {
3811 }
3813 {
3817 }
3818 else
3823 }
3825 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3826 with code CODE. This optimization is unsafe. */
3827 static tree
3829 {
3833 /* (A / C) +- (B / C) -> (A +- B) / C. */
3843 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3848 {
3860 }
3863 }
3864 \f
3865 /* Subroutine for fold_truthop: decode a field reference.
3867 If EXP is a comparison reference, we return the innermost reference.
3869 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3870 set to the starting bit number.
3872 If the innermost field can be completely contained in a mode-sized
3873 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3875 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3876 otherwise it is not changed.
3878 *PUNSIGNEDP is set to the signedness of the field.
3880 *PMASK is set to the mask used. This is either contained in a
3881 BIT_AND_EXPR or derived from the width of the field.
3883 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3885 Return 0 if this is not a component reference or is one that we can't
3886 do anything with. */
3888 static tree
3893 {
3897 tree unsigned_type;
3900 /* All the optimizations using this function assume integer fields.
3901 There are problems with FP fields since the type_for_size call
3902 below can fail for, e.g., XFmode. */
3906 /* We are interested in the bare arrangement of bits, so strip everything
3907 that doesn't affect the machine mode. However, record the type of the
3908 outermost expression if it may matter below. */
3915 {
3921 }
3930 /* If the number of bits in the reference is the same as the bitsize of
3931 the outer type, then the outer type gives the signedness. Otherwise
3932 (in case of a small bitfield) the signedness is unchanged. */
3936 /* Compute the mask to access the bitfield. */
3945 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3953 }
3955 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3956 represents the sign bit of EXP's type. If EXP represents a sign
3957 or zero extension, also test VAL against the unextended type.
3958 The return value is the (sub)expression whose sign bit is VAL,
3959 or NULL_TREE otherwise. */
3961 static tree
3963 {
3967 tree t;
3969 /* Tree EXP must have an integral type. */
3974 /* Tree VAL must be an integer constant. */
3981 {
3988 }
3989 else
3990 {
3997 }
3999 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
4000 treat VAL as if it were unsigned. */
4005 /* Handle extension from a narrower type. */
4011 }
4013 /* Subroutine for fold_truthop: determine if an operand is simple enough
4014 to be evaluated unconditionally. */
4016 static int
4018 {
4019 /* Strip any conversions that don't change the machine mode. */
4028 /* Don't regard global variables as simple. They may be
4029 allocated in ways unknown to the compiler (shared memory,
4030 #pragma weak, etc). */
4033 /* Loading a static variable is unduly expensive, but global
4034 registers aren't expensive. */
4036 }
4037 \f
4038 /* The following functions are subroutines to fold_range_test and allow it to
4039 try to change a logical combination of comparisons into a range test.
4041 For example, both
4042 X == 2 || X == 3 || X == 4 || X == 5
4043 and
4044 X >= 2 && X <= 5
4045 are converted to
4046 (unsigned) (X - 2) <= 3
4048 We describe each set of comparisons as being either inside or outside
4049 a range, using a variable named like IN_P, and then describe the
4050 range with a lower and upper bound. If one of the bounds is omitted,
4051 it represents either the highest or lowest value of the type.
4053 In the comments below, we represent a range by two numbers in brackets
4054 preceded by a "+" to designate being inside that range, or a "-" to
4055 designate being outside that range, so the condition can be inverted by
4056 flipping the prefix. An omitted bound is represented by a "-". For
4057 example, "- [-, 10]" means being outside the range starting at the lowest
4058 possible value and ending at 10, in other words, being greater than 10.
4059 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4060 always false.
4062 We set up things so that the missing bounds are handled in a consistent
4063 manner so neither a missing bound nor "true" and "false" need to be
4064 handled using a special case. */
4066 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4067 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4068 and UPPER1_P are nonzero if the respective argument is an upper bound
4069 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4070 must be specified for a comparison. ARG1 will be converted to ARG0's
4071 type if both are specified. */
4073 static tree
4076 {
4077 tree tem;
4081 /* If neither arg represents infinity, do the normal operation.
4082 Else, if not a comparison, return infinity. Else handle the special
4083 comparison rules. Note that most of the cases below won't occur, but
4084 are handled for consistency. */
4087 {
4092 }
4097 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4098 for neither. In real maths, we cannot assume open ended ranges are
4099 the same. But, this is computer arithmetic, where numbers are finite.
4100 We can therefore make the transformation of any unbounded range with
4101 the value Z, Z being greater than any representable number. This permits
4102 us to treat unbounded ranges as equal. */
4106 {
4127 }
4130 }
4131 \f
4132 /* Given EXP, a logical expression, set the range it is testing into
4133 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4134 actually being tested. *PLOW and *PHIGH will be made of the same
4135 type as the returned expression. If EXP is not a comparison, we
4136 will most likely not be returning a useful value and range. Set
4137 *STRICT_OVERFLOW_P to true if the return value is only valid
4138 because signed overflow is undefined; otherwise, do not change
4139 *STRICT_OVERFLOW_P. */
4141 static tree
4144 {
4151 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4152 and see if we can refine the range. Some of the cases below may not
4153 happen, but it doesn't seem worth worrying about this. We "continue"
4154 the outer loop when we've changed something; otherwise we "break"
4155 the switch, which will "break" the while. */
4161 {
4166 {
4178 }
4181 {
4188 /* We can only do something if the range is testing for zero
4189 and if the second operand is an integer constant. Note that
4190 saying something is "in" the range we make is done by
4191 complementing IN_P since it will set in the initial case of
4192 being not equal to zero; "out" is leaving it alone. */
4199 {
4220 }
4222 /* If this is an unsigned comparison, we also know that EXP is
4223 greater than or equal to zero. We base the range tests we make
4224 on that fact, so we record it here so we can parse existing
4225 range tests. We test arg0_type since often the return type
4226 of, e.g. EQ_EXPR, is boolean. */
4228 {
4232 NULL_TREE))
4237 /* If the high bound is missing, but we have a nonzero low
4238 bound, reverse the range so it goes from zero to the low bound
4239 minus 1. */
4241 {
4246 }
4247 }
4253 /* (-x) IN [a,b] -> x in [-b, -a] */
4265 /* ~ X -> -X - 1 */
4274 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4275 move a constant to the other side. */
4280 /* If EXP is signed, any overflow in the computation is undefined,
4281 so we don't worry about it so long as our computations on
4282 the bounds don't overflow. For unsigned, overflow is defined
4283 and this is exactly the right thing. */
4295 /* Check for an unsigned range which has wrapped around the maximum
4296 value thus making n_high < n_low, and normalize it. */
4298 {
4304 /* If the range is of the form +/- [ x+1, x ], we won't
4305 be able to normalize it. But then, it represents the
4306 whole range or the empty set, so make it
4307 +/- [ -, - ]. */
4311 else
4313 }
4314 else
4338 /* If we're converting arg0 from an unsigned type, to exp,
4339 a signed type, we will be doing the comparison as unsigned.
4340 The tests above have already verified that LOW and HIGH
4341 are both positive.
4343 So we have to ensure that we will handle large unsigned
4344 values the same way that the current signed bounds treat
4345 negative values. */
4348 {
4349 tree high_positive;
4350 tree equiv_type;
4351 /* For fixed-point modes, we need to pass the saturating flag
4352 as the 2nd parameter. */
4357 else
4361 /* A range without an upper bound is, naturally, unbounded.
4362 Since convert would have cropped a very large value, use
4363 the max value for the destination type. */
4364 high_positive
4371 high_positive),
4374 /* If the low bound is specified, "and" the range with the
4375 range for which the original unsigned value will be
4376 positive. */
4378 {
4382 integer_zero_node),
4383 high_positive))
4387 }
4388 else
4389 {
4390 /* Otherwise, "or" the range with the range of the input
4391 that will be interpreted as negative. */
4395 integer_zero_node),
4396 high_positive))
4400 }
4401 }
4409 }
4412 }
4414 /* If EXP is a constant, we can evaluate whether this is true or false. */
4416 {
4423 }
4427 }
4428 \f
4429 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4430 type, TYPE, return an expression to test if EXP is in (or out of, depending
4431 on IN_P) the range. Return 0 if the test couldn't be created. */
4433 static tree
4435 {
4437 tree value;
4439 #ifdef HAVE_canonicalize_funcptr_for_compare
4440 /* Disable this optimization for function pointer expressions
4441 on targets that require function pointer canonicalization. */
4446 #endif
4449 {
4455 }
4473 {
4475 {
4479 }
4481 }
4483 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4485 {
4487 HOST_WIDE_INT hi;
4492 {
4495 }
4496 else
4497 {
4500 }
4503 {
4505 {
4508 }
4511 }
4512 }
4514 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4515 This requires wrap-around arithmetics for the type of the expression. */
4517 {
4519 /* There is no requirement that LOW be within the range of ETYPE
4520 if the latter is a subtype. It must, however, be within the base
4521 type of ETYPE. So be sure we do the subtraction in that type. */
4534 }
4536 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4539 {
4542 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4543 for the type in question, as we rely on this here. */
4553 else
4555 }
4565 {
4567 {
4573 }
4575 }
4583 }
4584 \f
4585 /* Return the predecessor of VAL in its type, handling the infinite case. */
4587 static tree
4589 {
4595 else
4597 }
4599 /* Return the successor of VAL in its type, handling the infinite case. */
4601 static tree
4603 {
4609 else
4611 }
4613 /* Given two ranges, see if we can merge them into one. Return 1 if we
4614 can, 0 if we can't. Set the output range into the specified parameters. */
4616 static int
4619 {
4623 tree tem;
4633 /* Make range 0 be the range that starts first, or ends last if they
4634 start at the same value. Swap them if it isn't. */
4637 || (lowequal
4640 {
4644 }
4646 /* Now flag two cases, whether the ranges are disjoint or whether the
4647 second range is totally subsumed in the first. Note that the tests
4648 below are simplified by the ones above. */
4654 /* We now have four cases, depending on whether we are including or
4655 excluding the two ranges. */
4657 {
4658 /* If they don't overlap, the result is false. If the second range
4659 is a subset it is the result. Otherwise, the range is from the start
4660 of the second to the end of the first. */
4665 else
4667 }
4670 {
4671 /* If they don't overlap, the result is the first range. If they are
4672 equal, the result is false. If the second range is a subset of the
4673 first, and the ranges begin at the same place, we go from just after
4674 the end of the second range to the end of the first. If the second
4675 range is not a subset of the first, or if it is a subset and both
4676 ranges end at the same place, the range starts at the start of the
4677 first range and ends just before the second range.
4678 Otherwise, we can't describe this as a single range. */
4684 {
4689 {
4690 /* We are in the weird situation where high0 > high1 but
4691 high1 has no successor. Punt. */
4693 }
4694 }
4696 {
4701 {
4702 /* low0 < low1 but low1 has no predecessor. Punt. */
4704 }
4705 }
4706 else
4708 }
4711 {
4712 /* If they don't overlap, the result is the second range. If the second
4713 is a subset of the first, the result is false. Otherwise,
4714 the range starts just after the first range and ends at the
4715 end of the second. */
4720 else
4721 {
4726 {
4727 /* high1 > high0 but high0 has no successor. Punt. */
4729 }
4730 }
4731 }
4733 else
4734 {
4735 /* The case where we are excluding both ranges. Here the complex case
4736 is if they don't overlap. In that case, the only time we have a
4737 range is if they are adjacent. If the second is a subset of the
4738 first, the result is the first. Otherwise, the range to exclude
4739 starts at the beginning of the first range and ends at the end of the
4740 second. */
4742 {
4747 else
4748 {
4749 /* Canonicalize - [min, x] into - [-, x]. */
4752 {
4757 /* FALLTHROUGH */
4770 }
4772 /* Canonicalize - [x, max] into - [x, -]. */
4775 {
4780 /* FALLTHROUGH */
4795 }
4797 /* The ranges might be also adjacent between the maximum and
4798 minimum values of the given type. For
4799 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4800 return + [x + 1, y - 1]. */
4802 {
4809 }
4810 else
4812 }
4813 }
4816 else
4818 }
4822 }
4823 \f
4825 /* Subroutine of fold, looking inside expressions of the form
4826 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4827 of the COND_EXPR. This function is being used also to optimize
4828 A op B ? C : A, by reversing the comparison first.
4830 Return a folded expression whose code is not a COND_EXPR
4831 anymore, or NULL_TREE if no folding opportunity is found. */
4833 static tree
4835 {
4840 tree tem;
4845 /* If we have A op 0 ? A : -A, consider applying the following
4846 transformations:
4848 A == 0? A : -A same as -A
4849 A != 0? A : -A same as A
4850 A >= 0? A : -A same as abs (A)
4851 A > 0? A : -A same as abs (A)
4852 A <= 0? A : -A same as -abs (A)
4853 A < 0? A : -A same as -abs (A)
4855 None of these transformations work for modes with signed
4856 zeros. If A is +/-0, the first two transformations will
4857 change the sign of the result (from +0 to -0, or vice
4858 versa). The last four will fix the sign of the result,
4859 even though the original expressions could be positive or
4860 negative, depending on the sign of A.
4862 Note that all these transformations are correct if A is
4863 NaN, since the two alternatives (A and -A) are also NaNs. */
4870 /* In the case that A is of the form X-Y, '-A' (arg2) may
4871 have already been folded to Y-X, check for that. */
4879 {
4891 /* Fall through. */
4913 }
4915 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4916 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4917 both transformations are correct when A is NaN: A != 0
4918 is then true, and A == 0 is false. */
4922 {
4927 }
4929 /* Try some transformations of A op B ? A : B.
4931 A == B? A : B same as B
4932 A != B? A : B same as A
4933 A >= B? A : B same as max (A, B)
4934 A > B? A : B same as max (B, A)
4935 A <= B? A : B same as min (A, B)
4936 A < B? A : B same as min (B, A)
4938 As above, these transformations don't work in the presence
4939 of signed zeros. For example, if A and B are zeros of
4940 opposite sign, the first two transformations will change
4941 the sign of the result. In the last four, the original
4942 expressions give different results for (A=+0, B=-0) and
4943 (A=-0, B=+0), but the transformed expressions do not.
4945 The first two transformations are correct if either A or B
4946 is a NaN. In the first transformation, the condition will
4947 be false, and B will indeed be chosen. In the case of the
4948 second transformation, the condition A != B will be true,
4949 and A will be chosen.
4951 The conversions to max() and min() are not correct if B is
4952 a number and A is not. The conditions in the original
4953 expressions will be false, so all four give B. The min()
4954 and max() versions would give a NaN instead. */
4957 /* Avoid these transformations if the COND_EXPR may be used
4958 as an lvalue in the C++ front-end. PR c++/19199. */
4959 && (in_gimple_form
4964 {
4969 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4971 {
4975 }
4978 {
4987 /* In C++ a ?: expression can be an lvalue, so put the
4988 operand which will be used if they are equal first
4989 so that we can convert this back to the
4990 corresponding COND_EXPR. */
4992 {
4999 }
5006 {
5013 }
5026 }
5027 }
5029 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5030 we might still be able to simplify this. For example,
5031 if C1 is one less or one more than C2, this might have started
5032 out as a MIN or MAX and been transformed by this function.
5033 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5039 {
5041 /* We can replace A with C1 in this case. */
5046 /* If C1 is C2 + 1, this is min(A, C2). */
5048 OEP_ONLY_CONST)
5052 OEP_ONLY_CONST))
5054 type,
5056 arg2));
5060 /* If C1 is C2 - 1, this is min(A, C2). */
5062 OEP_ONLY_CONST)
5066 OEP_ONLY_CONST))
5068 type,
5070 arg2));
5074 /* If C1 is C2 - 1, this is max(A, C2). */
5076 OEP_ONLY_CONST)
5080 OEP_ONLY_CONST))
5082 type,
5084 arg2));
5088 /* If C1 is C2 + 1, this is max(A, C2). */
5090 OEP_ONLY_CONST)
5094 OEP_ONLY_CONST))
5096 type,
5098 arg2));
5104 }
5107 }
5110 \f
5111 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5112 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5113 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5114 false) >= 2)
5115 #endif
5117 /* EXP is some logical combination of boolean tests. See if we can
5118 merge it into some range test. Return the new tree if so. */
5120 static tree
5122 {
5130 tree tem;
5134 /* If this is an OR operation, invert both sides; we will invert
5135 again at the end. */
5139 /* If both expressions are the same, if we can merge the ranges, and we
5140 can build the range test, return it or it inverted. If one of the
5141 ranges is always true or always false, consider it to be the same
5142 expression as the other. */
5150 {
5154 }
5156 /* On machines where the branch cost is expensive, if this is a
5157 short-circuited branch and the underlying object on both sides
5158 is the same, make a non-short-circuit operation. */
5164 {
5165 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5166 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5167 which cases we can't do this. */
5175 {
5184 {
5187 WARN_STRICT_OVERFLOW_COMPARISON);
5191 }
5192 }
5193 }
5196 }
5197 \f
5198 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5199 bit value. Arrange things so the extra bits will be set to zero if and
5200 only if C is signed-extended to its full width. If MASK is nonzero,
5201 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5203 static tree
5205 {
5208 tree temp;
5213 /* We work by getting just the sign bit into the low-order bit, then
5214 into the high-order bit, then sign-extend. We then XOR that value
5215 with C. */
5219 /* We must use a signed type in order to get an arithmetic right shift.
5220 However, we must also avoid introducing accidental overflows, so that
5221 a subsequent call to integer_zerop will work. Hence we must
5222 do the type conversion here. At this point, the constant is either
5223 zero or one, and the conversion to a signed type can never overflow.
5224 We could get an overflow if this conversion is done anywhere else. */
5233 /* If necessary, convert the type back to match the type of C. */
5238 }
5239 \f
5240 /* Find ways of folding logical expressions of LHS and RHS:
5241 Try to merge two comparisons to the same innermost item.
5242 Look for range tests like "ch >= '0' && ch <= '9'".
5243 Look for combinations of simple terms on machines with expensive branches
5244 and evaluate the RHS unconditionally.
5246 For example, if we have p->a == 2 && p->b == 4 and we can make an
5247 object large enough to span both A and B, we can do this with a comparison
5248 against the object ANDed with the a mask.
5250 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5251 operations to do this with one comparison.
5253 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5254 function and the one above.
5256 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5257 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5259 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5260 two operands.
5262 We return the simplified tree or 0 if no optimization is possible. */
5264 static tree
5266 {
5267 /* If this is the "or" of two comparisons, we can do something if
5268 the comparisons are NE_EXPR. If this is the "and", we can do something
5269 if the comparisons are EQ_EXPR. I.e.,
5270 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5272 WANTED_CODE is this operation code. For single bit fields, we can
5273 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5274 comparison for one-bit fields. */
5296 /* Start by getting the comparison codes. Fail if anything is volatile.
5297 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5298 it were surrounded with a NE_EXPR. */
5307 {
5311 }
5314 {
5318 }
5329 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5332 {
5333 tree result;
5336 {
5341 }
5344 {
5350 }
5351 }
5356 /* If the RHS can be evaluated unconditionally and its operands are
5357 simple, it wins to evaluate the RHS unconditionally on machines
5358 with expensive branches. In this case, this isn't a comparison
5359 that can be merged. Avoid doing this if the RHS is a floating-point
5360 comparison since those can trap. */
5367 {
5368 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5379 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5391 {
5395 }
5396 }
5398 /* See if the comparisons can be merged. Then get all the parameters for
5399 each side. */
5423 /* It must be true that the inner operation on the lhs of each
5424 comparison must be the same if we are to be able to do anything.
5425 Then see if we have constants. If not, the same must be true for
5426 the rhs's. */
5437 else
5440 /* If either comparison code is not correct for our logical operation,
5441 fail. However, we can convert a one-bit comparison against zero into
5442 the opposite comparison against that bit being set in the field. */
5446 {
5448 {
5449 /* Make the left operand unsigned, since we are only interested
5450 in the value of one bit. Otherwise we are doing the wrong
5451 thing below. */
5454 }
5455 else
5457 }
5459 /* This is analogous to the code for l_const above. */
5461 {
5463 {
5466 }
5467 else
5469 }
5471 /* See if we can find a mode that contains both fields being compared on
5472 the left. If we can't, fail. Otherwise, update all constants and masks
5473 to be relative to a field of that size. */
5478 volatilep);
5488 {
5491 }
5499 {
5507 {
5511 }
5512 }
5514 {
5522 {
5526 }
5527 }
5529 /* Handle the case of comparisons with constants. If there is something in
5530 common between the masks, those bits of the constants must be the same.
5531 If not, the condition is always false. Test for this to avoid generating
5532 incorrect code below. */
5537 {
5539 {
5542 }
5543 else
5544 {
5547 }
5548 }
5551 }
5552 \f
5553 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5554 constant. */
5556 static tree
5558 {
5561 tree comp_const;
5562 tree minmax_const;
5564 tree inner;
5575 /* If something does not permit us to optimize, return the original tree. */
5583 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5584 and GT_EXPR, doing the rest with recursive calls using logical
5585 simplifications. */
5587 {
5589 {
5595 }
5598 return
5600 optimize_minmax_comparison
5602 optimize_minmax_comparison
5607 /* MAX (X, 0) == 0 -> X <= 0 */
5611 /* MAX (X, 0) == 5 -> X == 5 */
5615 /* MAX (X, 0) == -1 -> false */
5619 /* MIN (X, 0) == 0 -> X >= 0 */
5623 /* MIN (X, 0) == 5 -> false */
5626 else
5627 /* MIN (X, 0) == -1 -> X == -1 */
5632 /* MAX (X, 0) > 0 -> X > 0
5633 MAX (X, 0) > 5 -> X > 5 */
5637 /* MAX (X, 0) > -1 -> true */
5641 /* MIN (X, 0) > 0 -> false
5642 MIN (X, 0) > 5 -> false */
5645 else
5646 /* MIN (X, 0) > -1 -> X > -1 */
5651 }
5652 }
5653 \f
5654 /* T is an integer expression that is being multiplied, divided, or taken a
5655 modulus (CODE says which and what kind of divide or modulus) by a
5656 constant C. See if we can eliminate that operation by folding it with
5657 other operations already in T. WIDE_TYPE, if non-null, is a type that
5658 should be used for the computation if wider than our type.
5660 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5661 (X * 2) + (Y * 4). We must, however, be assured that either the original
5662 expression would not overflow or that overflow is undefined for the type
5663 in the language in question.
5665 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5666 the machine has a multiply-accumulate insn or that this is part of an
5667 addressing calculation.
5669 If we return a non-null expression, it is an equivalent form of the
5670 original computation, but need not be in the original type.
5672 We set *STRICT_OVERFLOW_P to true if the return values depends on
5673 signed overflow being undefined. Otherwise we do not change
5674 *STRICT_OVERFLOW_P. */
5676 static tree
5679 {
5680 /* To avoid exponential search depth, refuse to allow recursion past
5681 three levels. Beyond that (1) it's highly unlikely that we'll find
5682 something interesting and (2) we've probably processed it before
5683 when we built the inner expression. */
5686 tree ret;
5691 depth++;
5693 depth--;
5696 }
5698 static tree
5701 {
5712 /* Don't deal with constants of zero here; they confuse the code below. */
5722 /* Note that we need not handle conditional operations here since fold
5723 already handles those cases. So just do arithmetic here. */
5725 {
5727 /* For a constant, we can always simplify if we are a multiply
5728 or (for divide and modulus) if it is a multiple of our constant. */
5736 /* If op0 is an expression ... */
5742 /* ... and has wrapping overflow, and its type is smaller
5743 than ctype, then we cannot pass through as widening. */
5749 /* ... or this is a truncation (t is narrower than op0),
5750 then we cannot pass through this narrowing. */
5753 /* ... or signedness changes for division or modulus,
5754 then we cannot pass through this conversion. */
5758 /* ... or has undefined overflow while the converted to
5759 type has not, we cannot do the operation in the inner type
5760 as that would introduce undefined overflow. */
5765 /* Pass the constant down and see if we can make a simplification. If
5766 we can, replace this expression with the inner simplification for
5767 possible later conversion to our or some other type. */
5772 code == MULT_EXPR
5774 strict_overflow_p))))
5779 /* If widening the type changes it from signed to unsigned, then we
5780 must avoid building ABS_EXPR itself as unsigned. */
5782 {
5786 {
5789 }
5791 }
5792 /* If the constant is negative, we cannot simplify this. */
5795 /* FALLTHROUGH */
5803 /* If widening the type changes the signedness, then we can't perform
5804 this optimization as that changes the result. */
5808 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5814 {
5821 }
5825 /* If the second operand is constant, this is a multiplication
5826 or floor division, by a power of two, so we can treat it that
5827 way unless the multiplier or divisor overflows. Signed
5828 left-shift overflow is implementation-defined rather than
5829 undefined in C90, so do not convert signed left shift into
5830 multiplication. */
5833 /* const_binop may not detect overflow correctly,
5834 so check for it explicitly here. */
5839 size_one_node,
5849 /* See if we can eliminate the operation on both sides. If we can, we
5850 can return a new PLUS or MINUS. If we can't, the only remaining
5851 cases where we can do anything are if the second operand is a
5852 constant. */
5858 /* If not multiplication, we can only do this if both operands
5859 are divisible by c. */
5862 {
5867 }
5869 /* If this was a subtraction, negate OP1 and set it to be an addition.
5870 This simplifies the logic below. */
5877 /* If either OP1 or C are negative, this optimization is not safe for
5878 some of the division and remainder types while for others we need
5879 to change the code. */
5881 {
5889 }
5891 /* If it's a multiply or a division/modulus operation of a multiple
5892 of our constant, do the operation and verify it doesn't overflow. */
5895 {
5898 /* We allow the constant to overflow with wrapping semantics. */
5902 }
5903 else
5906 /* If we have an unsigned type is not a sizetype, we cannot widen
5907 the operation since it will change the result if the original
5908 computation overflowed. */
5914 /* If we were able to eliminate our operation from the first side,
5915 apply our operation to the second side and reform the PLUS. */
5919 /* The last case is if we are a multiply. In that case, we can
5920 apply the distributive law to commute the multiply and addition
5921 if the multiplication of the constants doesn't overflow. */
5927 op1);
5932 /* We have a special case here if we are doing something like
5933 (C * 8) % 4 since we know that's zero. */
5936 /* If the multiplication can overflow we cannot optimize this.
5937 ??? Until we can properly mark individual operations as
5938 not overflowing we need to treat sizetype special here as
5939 stor-layout relies on this opimization to make
5940 DECL_FIELD_BIT_OFFSET always a constant. */
5946 {
5949 }
5951 /* ... fall through ... */
5955 /* If we can extract our operation from the LHS, do so and return a
5956 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5957 do something only if the second operand is a constant. */
5971 /* If these are the same operation types, we can associate them
5972 assuming no overflow. */
5984 /* If these operations "cancel" each other, we have the main
5985 optimizations of this pass, which occur when either constant is a
5986 multiple of the other, in which case we replace this with either an
5987 operation or CODE or TCODE.
5989 If we have an unsigned type that is not a sizetype, we cannot do
5990 this since it will change the result if the original computation
5991 overflowed. */
5999 {
6001 {
6008 }
6010 {
6017 }
6018 }
6023 }
6026 }
6027 \f
6028 /* Return a node which has the indicated constant VALUE (either 0 or
6029 1), and is of the indicated TYPE. */
6031 tree
6033 {
6038 else
6040 }
6043 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6044 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6045 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6046 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6047 COND is the first argument to CODE; otherwise (as in the example
6048 given here), it is the second argument. TYPE is the type of the
6049 original expression. Return NULL_TREE if no simplification is
6050 possible. */
6052 static tree
6056 {
6063 /* This transformation is only worthwhile if we don't have to wrap
6064 arg in a SAVE_EXPR, and the operation can be simplified on at least
6065 one of the branches once its pushed inside the COND_EXPR. */
6070 {
6074 /* If this operand throws an expression, then it does not make
6075 sense to try to perform a logical or arithmetic operation
6076 involving it. */
6081 }
6082 else
6083 {
6088 }
6092 {
6096 else
6098 }
6100 {
6104 else
6106 }
6110 }
6112 \f
6113 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6115 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6116 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6117 ADDEND is the same as X.
6119 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6120 and finite. The problematic cases are when X is zero, and its mode
6121 has signed zeros. In the case of rounding towards -infinity,
6122 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6123 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6125 bool
6127 {
6131 /* Don't allow the fold with -fsignaling-nans. */
6135 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6139 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6144 /* The mode has signed zeros, and we have to honor their sign.
6145 In this situation, there is only one case we can return true for.
6146 X - 0 is the same as X unless rounding towards -infinity is
6147 supported. */
6149 }
6151 /* Subroutine of fold() that checks comparisons of built-in math
6152 functions against real constants.
6154 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6155 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6156 is the type of the result and ARG0 and ARG1 are the operands of the
6157 comparison. ARG1 must be a TREE_REAL_CST.
6159 The function returns the constant folded tree if a simplification
6160 can be made, and NULL_TREE otherwise. */
6162 static tree
6165 {
6166 REAL_VALUE_TYPE c;
6169 {
6175 {
6176 /* sqrt(x) < y is always false, if y is negative. */
6180 /* sqrt(x) > y is always true, if y is negative and we
6181 don't care about NaNs, i.e. negative values of x. */
6185 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6188 }
6190 {
6191 REAL_VALUE_TYPE c2;
6197 {
6198 /* sqrt(x) > y is x == +Inf, when y is very large. */
6203 /* sqrt(x) > y is always false, when y is very large
6204 and we don't care about infinities. */
6206 }
6208 /* sqrt(x) > c is the same as x > c*c. */
6211 }
6213 {
6214 REAL_VALUE_TYPE c2;
6220 {
6221 /* sqrt(x) < y is always true, when y is a very large
6222 value and we don't care about NaNs or Infinities. */
6226 /* sqrt(x) < y is x != +Inf when y is very large and we
6227 don't care about NaNs. */
6232 /* sqrt(x) < y is x >= 0 when y is very large and we
6233 don't care about Infinities. */
6238 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6247 dconst0)),
6250 c2)));
6251 }
6253 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6258 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6261 {
6266 dconst0)),
6269 c2)));
6270 }
6271 }
6272 }
6275 }
6277 /* Subroutine of fold() that optimizes comparisons against Infinities,
6278 either +Inf or -Inf.
6280 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6281 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6282 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6284 The function returns the constant folded tree if a simplification
6285 can be made, and NULL_TREE otherwise. */
6287 static tree
6289 {
6291 REAL_VALUE_TYPE max;
6292 tree temp;
6297 /* For negative infinity swap the sense of the comparison. */
6303 {
6305 /* x > +Inf is always false, if with ignore sNANs. */
6311 /* x <= +Inf is always true, if we don't case about NaNs. */
6315 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6318 {
6321 }
6326 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6332 /* x < +Inf is always equal to x <= DBL_MAX. */
6338 /* x != +Inf is always equal to !(x > DBL_MAX). */
6350 }
6353 }
6355 /* Subroutine of fold() that optimizes comparisons of a division by
6356 a nonzero integer constant against an integer constant, i.e.
6357 X/C1 op C2.
6359 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6360 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6361 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6363 The function returns the constant folded tree if a simplification
6364 can be made, and NULL_TREE otherwise. */
6366 static tree
6368 {
6373 HOST_WIDE_INT hpart;
6378 /* We have to do this the hard way to detect unsigned overflow.
6379 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6390 {
6395 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6403 }
6405 {
6409 {
6428 }
6429 }
6430 else
6431 {
6432 /* A negative divisor reverses the relational operators. */
6438 {
6457 }
6458 }
6461 {
6482 {
6485 }
6490 {
6493 }
6498 {
6501 }
6506 {
6509 }
6514 }
6517 }
6520 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6521 equality/inequality test, then return a simplified form of the test
6522 using a sign testing. Otherwise return NULL. TYPE is the desired
6523 result type. */
6525 static tree
6527 tree result_type)
6528 {
6529 /* If this is testing a single bit, we can optimize the test. */
6533 {
6534 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6535 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6539 /* This is only a win if casting to a signed type is cheap,
6540 i.e. when arg00's type is not a partial mode. */
6543 {
6548 }
6549 }
6552 }
6554 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6555 equality/inequality test, then return a simplified form of
6556 the test using shifts and logical operations. Otherwise return
6557 NULL. TYPE is the desired result type. */
6559 tree
6561 tree result_type)
6562 {
6563 /* If this is testing a single bit, we can optimize the test. */
6567 {
6576 /* First, see if we can fold the single bit test into a sign-bit
6577 test. */
6579 result_type);
6583 /* Otherwise we have (A & C) != 0 where C is a single bit,
6584 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6585 Similarly for (A & C) == 0. */
6587 /* If INNER is a right shift of a constant and it plus BITNUM does
6588 not overflow, adjust BITNUM and INNER. */
6595 {
6598 }
6600 /* If we are going to be able to omit the AND below, we must do our
6601 operations as unsigned. If we must use the AND, we have a choice.
6602 Normally unsigned is faster, but for some machines signed is. */
6603 #ifdef LOAD_EXTEND_OP
6606 #else
6608 #endif
6624 /* Put the AND last so it can combine with more things. */
6627 /* Make sure to return the proper type. */
6631 }
6633 }
6635 /* Check whether we are allowed to reorder operands arg0 and arg1,
6636 such that the evaluation of arg1 occurs before arg0. */
6638 static bool
6640 {
6647 }
6649 /* Test whether it is preferable two swap two operands, ARG0 and
6650 ARG1, for example because ARG0 is an integer constant and ARG1
6651 isn't. If REORDER is true, only recommend swapping if we can
6652 evaluate the operands in reverse order. */
6654 bool
6656 {
6692 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6693 for commutative and comparison operators. Ensuring a canonical
6694 form allows the optimizers to find additional redundancies without
6695 having to explicitly check for both orderings. */
6701 /* Put SSA_NAMEs last. */
6707 /* Put variables last. */
6714 }
6716 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6717 ARG0 is extended to a wider type. */
6719 static tree
6721 {
6723 tree arg1_unw;
6732 #ifdef HAVE_canonicalize_funcptr_for_compare
6733 /* Disable this optimization if we're casting a function pointer
6734 type on targets that require function pointer canonicalization. */
6739 #endif
6746 /* If possible, express the comparison in the shorter mode. */
6766 /* If we are comparing with the integer that does not fit into the range
6767 of the shorter type, the result is known. */
6778 {
6805 }
6808 }
6810 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6811 ARG0 just the signedness is changed. */
6813 static tree
6816 {
6817 tree arg0_inner;
6827 #ifdef HAVE_canonicalize_funcptr_for_compare
6828 /* Disable this optimization if we're casting a function pointer
6829 type on targets that require function pointer canonicalization. */
6834 #endif
6839 /* If the conversion is from an integral subtype to its basetype
6840 leave it alone. */
6859 else
6863 }
6865 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6866 step of the array. Reconstructs s and delta in the case of s * delta
6867 being an integer constant (and thus already folded).
6868 ADDR is the address. MULT is the multiplicative expression.
6869 If the function succeeds, the new address expression is returned. Otherwise
6870 NULL_TREE is returned. */
6872 static tree
6874 {
6878 tree itype;
6881 /* Strip the nops that might be added when converting op1 to sizetype. */
6884 /* Canonicalize op1 into a possibly non-constant delta
6885 and an INTEGER_CST s. */
6887 {
6894 {
6897 }
6899 {
6902 }
6903 else
6905 }
6907 {
6910 }
6911 else
6912 {
6913 /* Simulate we are delta * 1. */
6916 }
6919 {
6921 {
6922 /* Remember if this was a multi-dimensional array. */
6935 {
6938 }
6939 else
6940 {
6941 /* Try if delta is a multiple of step. */
6946 }
6948 /* Only fold here if we can verify we do not overflow one
6949 dimension of a multi-dimensional array. */
6951 {
6952 tree tmp;
6968 }
6971 }
6972 else
6977 }
6979 /* We found the suitable array reference. So copy everything up to it,
6980 and replace the index. */
6987 {
6991 }
6999 }
7002 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7003 means A >= Y && A != MAX, but in this case we know that
7004 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7006 static tree
7008 {
7015 else
7024 {
7027 }
7029 {
7032 }
7033 else
7040 {
7041 /* Convert the pointer types into integer before taking the difference. */
7045 }
7046 else
7053 }
7055 /* Fold a sum or difference of at least one multiplication.
7056 Returns the folded tree or NULL if no simplification could be made. */
7058 static tree
7060 {
7064 /* (A * C) +- (B * C) -> (A+-B) * C.
7065 (A * C) +- A -> A * (C+-1).
7066 We are most concerned about the case where C is a constant,
7067 but other combinations show up during loop reduction. Since
7068 it is not difficult, try all four possibilities. */
7071 {
7074 }
7076 {
7079 }
7080 else
7081 {
7082 /* We cannot generate constant 1 for fract. */
7087 }
7089 {
7092 }
7094 {
7097 }
7098 else
7099 {
7100 /* We cannot generate constant 1 for fract. */
7105 }
7117 /* No identical multiplicands; see if we can find a common
7118 power-of-two factor in non-power-of-two multiplies. This
7119 can help in multi-dimensional array access. */
7122 {
7125 tree maybe_same;
7129 /* Move min of absolute values to int11. */
7132 {
7137 }
7138 else
7142 {
7150 }
7151 }
7161 }
7163 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7164 specified by EXPR into the buffer PTR of length LEN bytes.
7165 Return the number of bytes placed in the buffer, or zero
7166 upon failure. */
7168 static int
7170 {
7181 {
7185 else
7190 {
7197 else
7199 }
7200 else
7203 }
7205 }
7208 /* Subroutine of native_encode_expr. Encode the REAL_CST
7209 specified by EXPR into the buffer PTR of length LEN bytes.
7210 Return the number of bytes placed in the buffer, or zero
7211 upon failure. */
7213 static int
7215 {
7221 /* There are always 32 bits in each long, no matter the size of
7222 the hosts long. We handle floating point representations with
7223 up to 192 bits. */
7234 {
7239 {
7246 else
7248 }
7249 else
7252 }
7254 }
7256 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7257 specified by EXPR into the buffer PTR of length LEN bytes.
7258 Return the number of bytes placed in the buffer, or zero
7259 upon failure. */
7261 static int
7263 {
7265 tree part;
7276 }
7279 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7280 specified by EXPR into the buffer PTR of length LEN bytes.
7281 Return the number of bytes placed in the buffer, or zero
7282 upon failure. */
7284 static int
7286 {
7296 {
7298 {
7301 }
7302 else
7306 {
7309 }
7310 else
7311 {
7315 }
7317 }
7319 }
7322 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7323 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7324 buffer PTR of length LEN bytes. Return the number of bytes
7325 placed in the buffer, or zero upon failure. */
7327 int
7329 {
7331 {
7346 }
7347 }
7350 /* Subroutine of native_interpret_expr. Interpret the contents of
7351 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7352 If the buffer cannot be interpreted, return NULL_TREE. */
7354 static tree
7356 {
7370 {
7373 {
7380 else
7382 }
7383 else
7389 else
7392 }
7395 }
7398 /* Subroutine of native_interpret_expr. Interpret the contents of
7399 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7400 If the buffer cannot be interpreted, return NULL_TREE. */
7402 static tree
7404 {
7409 /* There are always 32 bits in each long, no matter the size of
7410 the hosts long. We handle floating point representations with
7411 up to 192 bits. */
7412 REAL_VALUE_TYPE r;
7423 {
7426 {
7433 else
7435 }
7436 else
7441 }
7445 }
7448 /* Subroutine of native_interpret_expr. Interpret the contents of
7449 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7450 If the buffer cannot be interpreted, return NULL_TREE. */
7452 static tree
7454 {
7469 }
7472 /* Subroutine of native_interpret_expr. Interpret the contents of
7473 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7474 If the buffer cannot be interpreted, return NULL_TREE. */
7476 static tree
7478 {
7490 {
7495 }
7497 }
7500 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7501 the buffer PTR of length LEN as a constant of type TYPE. For
7502 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7503 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7504 return NULL_TREE. */
7506 tree
7508 {
7510 {
7527 }
7528 }
7531 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7532 TYPE at compile-time. If we're unable to perform the conversion
7533 return NULL_TREE. */
7535 static tree
7537 {
7538 /* We support up to 512-bit values (for V8DFmode). */
7542 /* Check that the host and target are sane. */
7551 }
7553 /* Build an expression for the address of T. Folds away INDIRECT_REF
7554 to avoid confusing the gimplify process. When IN_FOLD is true
7555 avoid modifications of T. */
7557 static tree
7559 {
7560 /* The size of the object is not relevant when talking about its address. */
7564 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7567 {
7572 }
7574 {
7584 }
7585 else
7589 }
7591 /* Build an expression for the address of T with type PTRTYPE. This
7592 function modifies the input parameter 'T' by sometimes setting the
7593 TREE_ADDRESSABLE flag. */
7595 tree
7597 {
7599 }
7601 /* Build an expression for the address of T. This function modifies
7602 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7603 flag. When called from fold functions, use fold_addr_expr instead. */
7605 tree
7607 {
7611 }
7613 /* Same as build_fold_addr_expr, builds an expression for the address
7614 of T, but avoids touching the input node 't'. Fold functions
7615 should use this version. */
7617 static tree
7619 {
7623 }
7625 /* Fold a unary expression of code CODE and type TYPE with operand
7626 OP0. Return the folded expression if folding is successful.
7627 Otherwise, return NULL_TREE. */
7629 tree
7631 {
7632 tree tem;
7633 tree arg0;
7641 {
7644 {
7645 /* Don't use STRIP_NOPS, because signedness of argument type
7646 matters. */
7648 }
7649 else
7650 {
7651 /* Strip any conversions that don't change the mode. This
7652 is safe for every expression, except for a comparison
7653 expression because its signedness is derived from its
7654 operands.
7656 Note that this is done as an internal manipulation within
7657 the constant folder, in order to find the simplest
7658 representation of the arguments so that their form can be
7659 studied. In any cases, the appropriate type conversions
7660 should be put back in the tree that will get out of the
7661 constant folder. */
7663 }
7664 }
7667 {
7672 {
7682 /* If this was a conversion, and all we did was to move into
7683 inside the COND_EXPR, bring it back out. But leave it if
7684 it is a conversion from integer to integer and the
7685 result precision is no wider than a word since such a
7686 conversion is cheap and may be optimized away by combine,
7687 while it couldn't if it were outside the COND_EXPR. Then return
7688 so we don't get into an infinite recursion loop taking the
7689 conversion out and then back in. */
7701 && (INTEGRAL_TYPE_P
7713 }
7715 {
7717 {
7721 }
7725 integer_one_node),
7727 integer_zero_node));
7728 }
7729 }
7732 {
7734 /* Re-association barriers around constants and other re-association
7735 barriers can be removed. */
7741 CASE_CONVERT:
7747 /* If we have (type) (a CMP b) and type is an integral type, return
7748 new expression involving the new type. */
7753 /* Handle cases of two conversions in a row. */
7755 {
7777 /* In addition to the cases of two conversions in a row
7778 handled below, if we are converting something to its own
7779 type via an object of identical or wider precision, neither
7780 conversion is needed. */
7787 /* Likewise, if the intermediate and final types are either both
7788 float or both integer, we don't need the middle conversion if
7789 it is wider than the final type and doesn't change the signedness
7790 (for integers). Avoid this if the final type is a pointer
7791 since then we sometimes need the inner conversion. Likewise if
7792 the outer has a precision not equal to the size of its mode. */
7801 && ! final_ptr
7805 /* If we have a sign-extension of a zero-extended value, we can
7806 replace that by a single zero-extension. */
7812 /* Two conversions in a row are not needed unless:
7813 - some conversion is floating-point (overstrict for now), or
7814 - some conversion is a vector (overstrict for now), or
7815 - the intermediate type is narrower than both initial and
7816 final, or
7817 - the intermediate type and innermost type differ in signedness,
7818 and the outermost type is wider than the intermediate, or
7819 - the initial type is a pointer type and the precisions of the
7820 intermediate and final types differ, or
7821 - the final type is a pointer type and the precisions of the
7822 initial and intermediate types differ. */
7836 }
7838 /* Handle (T *)&A.B.C for A being of type T and B and C
7839 living at offset zero. This occurs frequently in
7840 C++ upcasting and then accessing the base. */
7844 {
7846 tree offset;
7852 /* If the reference was to a (constant) zero offset, we can use
7853 the address of the base if it has the same base type
7854 as the result type. */
7859 }
7863 /* Detect assigning a bitfield. */
7865 && DECL_BIT_FIELD
7867 {
7868 /* Don't leave an assignment inside a conversion
7869 unless assigning a bitfield. */
7871 /* First do the assignment, then return converted constant. */
7876 }
7878 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7879 constants (if x has signed type, the sign bit cannot be set
7880 in c). This folds extension into the BIT_AND_EXPR.
7881 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7882 very likely don't have maximal range for their precision and this
7883 transformation effectively doesn't preserve non-maximal ranges. */
7887 /* Not if the conversion is to the sub-type. */
7889 {
7899 <= HOST_BITS_PER_WIDE_INT
7901 {
7908 #ifdef LOAD_EXTEND_OP
7910 && !flag_syntax_only
7913 {
7917 }
7918 #endif
7919 }
7921 {
7927 }
7928 }
7930 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7931 when one of the new casts will fold away. Conservatively we assume
7932 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7938 {
7944 }
7946 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7947 of the same precision, and X is an integer type not narrower than
7948 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7954 {
7959 }
7961 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7962 type of X and Y (integer types only). */
7967 {
7968 /* Be careful not to introduce new overflows. */
7969 tree mult_type;
7972 else
7979 }
7994 /* For integral conversions with the same precision or pointer
7995 conversions use a NOP_EXPR instead. */
8001 /* Do not muck with VIEW_CONVERT_EXPRs that convert from
8002 a sub-type to its base type as generated by the Ada FE. */
8007 /* Strip inner integral conversions that do not change the precision. */
8030 /* Convert fabs((double)float) into (double)fabsf(float). */
8033 {
8038 targ0));
8039 }
8040 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8046 /* Strip sign ops from argument. */
8048 {
8052 }
8059 {
8064 }
8066 {
8071 }
8081 /* Convert ~ (-A) to A - 1. */
8086 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8094 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8107 /* Perform BIT_NOT_EXPR on each element individually. */
8109 {
8114 {
8116 {
8122 }
8123 else
8126 }
8129 }
8134 /* The argument to invert_truthvalue must have Boolean type. */
8138 /* Note that the operand of this must be an int
8139 and its values must be 0 or 1.
8140 ("true" is a fixed value perhaps depending on the language,
8141 but we don't handle values other than 1 correctly yet.) */
8156 {
8164 }
8166 {
8170 }
8172 {
8176 {
8185 }
8186 }
8198 {
8206 }
8208 {
8212 }
8214 {
8218 {
8227 }
8228 }
8234 }
8236 /* Fold a binary expression of code CODE and type TYPE with operands
8237 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8238 Return the folded expression if folding is successful. Otherwise,
8239 return NULL_TREE. */
8241 static tree
8243 {
8250 else
8253 /* MIN (MAX (a, b), b) == b. */
8258 /* MIN (MAX (b, a), b) == b. */
8264 /* MIN (a, MAX (a, b)) == a. */
8270 /* MIN (a, MAX (b, a)) == a. */
8277 }
8279 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8280 by changing CODE to reduce the magnitude of constants involved in
8281 ARG0 of the comparison.
8282 Returns a canonicalized comparison tree if a simplification was
8283 possible, otherwise returns NULL_TREE.
8284 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8285 valid if signed overflow is undefined. */
8287 static tree
8291 {
8297 /* Match A +- CST code arg1 and CST code arg1. We can change the
8298 first form only if overflow is undefined. */
8300 /* In principle pointers also have undefined overflow behavior,
8301 but that causes problems elsewhere. */
8309 /* Identify the constant in arg0 and its sign. */
8312 else
8316 /* Overflowed constants and zero will cause problems. */
8321 /* See if we can reduce the magnitude of the constant in
8322 arg0 by changing the comparison code. */
8324 {
8325 /* CST <= arg1 -> CST-1 < arg1. */
8328 /* -CST < arg1 -> -CST-1 <= arg1. */
8331 /* CST > arg1 -> CST-1 >= arg1. */
8334 /* -CST >= arg1 -> -CST-1 > arg1. */
8337 else
8339 /* arg1 code' CST' might be more canonical. */
8341 }
8342 else
8343 {
8344 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8348 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8352 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8356 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8360 else
8363 }
8365 /* Now build the constant reduced in magnitude. But not if that
8366 would produce one outside of its types range. */
8374 /* We cannot swap the comparison here as that would cause us to
8375 endlessly recurse. */
8383 /* If swapping might yield to a more canonical form, do so. */
8386 else
8388 }
8390 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8391 overflow further. Try to decrease the magnitude of constants involved
8392 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8393 and put sole constants at the second argument position.
8394 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8396 static tree
8399 {
8400 tree t;
8405 /* Try canonicalization by simplifying arg0. */
8410 {
8414 }
8416 /* Try canonicalization by simplifying arg1 using the swapped
8417 comparison. */
8425 }
8427 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8428 space. This is used to avoid issuing overflow warnings for
8429 expressions like &p->x which can not wrap. */
8431 static bool
8433 {
8444 {
8447 }
8450 else
8451 {
8454 }
8469 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8470 array. */
8472 {
8473 HOST_WIDE_INT base_size;
8478 }
8481 }
8483 /* Subroutine of fold_binary. This routine performs all of the
8484 transformations that are common to the equality/inequality
8485 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8486 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8487 fold_binary should call fold_binary. Fold a comparison with
8488 tree code CODE and type TYPE with operands OP0 and OP1. Return
8489 the folded comparison or NULL_TREE. */
8491 static tree
8493 {
8506 /* If one arg is a real or integer constant, put it last. */
8510 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8517 {
8521 tree lhs;
8528 /* If the constant operation overflowed this can be
8529 simplified as a comparison against INT_MAX/INT_MIN. */
8532 {
8536 /* Get the sign of the constant on the lhs if the
8537 operation were VARIABLE + CONST1. */
8541 /* The sign of the constant determines if we overflowed
8542 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8543 Canonicalize to the INT_MIN overflow by swapping the comparison
8544 if necessary. */
8548 /* We now can look at the canonicalized case
8549 VARIABLE + 1 CODE2 INT_MIN
8550 and decide on the result. */
8559 }
8564 {
8566 "when changing X +- C1 cmp C2 to "
8568 WARN_STRICT_OVERFLOW_COMPARISON);
8570 }
8571 }
8573 /* For comparisons of pointers we can decompose it to a compile time
8574 comparison of the base objects and the offsets into the object.
8575 This requires at least one operand being an ADDR_EXPR or a
8576 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8582 {
8589 /* Get base and offset for the access. Strip ADDR_EXPR for
8590 get_inner_reference, but put it back by stripping INDIRECT_REF
8591 off the base object if possible. indirect_baseN will be true
8592 if baseN is not an address but refers to the object itself. */
8595 {
8601 else
8603 }
8605 {
8608 }
8612 {
8618 else
8620 }
8622 {
8625 }
8627 /* If we have equivalent bases we might be able to simplify. */
8630 {
8631 /* We can fold this expression to a constant if the non-constant
8632 offset parts are equal. */
8640 {
8647 "occur when comparing P +- C1 with "
8649 WARN_STRICT_OVERFLOW_CONDITIONAL);
8652 {
8666 }
8667 }
8668 /* We can simplify the comparison to a comparison of the variable
8669 offset parts if the constant offset parts are equal.
8670 Be careful to use signed size type here because otherwise we
8671 mess with array offsets in the wrong way. This is possible
8672 because pointer arithmetic is restricted to retain within an
8673 object and overflow on pointer differences is undefined as of
8674 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8678 {
8679 tree signed_size_type_node;
8682 /* By converting to signed size type we cover middle-end pointer
8683 arithmetic which operates on unsigned pointer types of size
8684 type size and ARRAY_REF offsets which are properly sign or
8685 zero extended from their type in case it is narrower than
8686 size type. */
8689 else
8693 else
8701 "occur when comparing P +- C1 with "
8703 WARN_STRICT_OVERFLOW_COMPARISON);
8706 }
8707 }
8708 /* For non-equal bases we can simplify if they are addresses
8709 of local binding decls or constants. */
8711 /* We know that !operand_equal_p (base0, base1, 0)
8712 because the if condition was false. But make
8713 sure two decls are not the same. */
8727 {
8732 }
8733 /* For equal offsets we can simplify to a comparison of the
8734 base addresses. */
8736 && (indirect_base0
8738 && (indirect_base1
8743 {
8749 }
8750 }
8752 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8753 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8754 the resulting offset is smaller in absolute value than the
8755 original one. */
8763 {
8768 tree cst;
8770 "occur when combining constants around "
8773 /* Put the constant on the side where it doesn't overflow and is
8774 of lower absolute value than before. */
8780 {
8783 variable1,
8786 }
8793 {
8798 variable2);
8799 }
8800 }
8802 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8803 signed arithmetic case. That form is created by the compiler
8804 often enough for folding it to be of value. One example is in
8805 computing loop trip counts after Operator Strength Reduction. */
8811 {
8820 "eliminating multiplication in comparison "
8822 WARN_STRICT_OVERFLOW_COMPARISON);
8824 /* If const1 is negative we swap the sense of the comparison. */
8829 }
8836 {
8844 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8849 /* (-a) CMP (-b) -> b CMP a */
8856 {
8857 REAL_VALUE_TYPE cst;
8860 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8867 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8868 /* a CMP (-0) -> a CMP 0 */
8873 /* x != NaN is always true, other ops are always false. */
8876 {
8879 }
8881 /* Fold comparisons against infinity. */
8883 {
8887 }
8888 }
8890 /* If this is a comparison of a real constant with a PLUS_EXPR
8891 or a MINUS_EXPR of a real constant, we can convert it into a
8892 comparison with a revised real constant as long as no overflow
8893 occurs when unsafe_math_optimizations are enabled. */
8905 /* Likewise, we can simplify a comparison of a real constant with
8906 a MINUS_EXPR whose first operand is also a real constant, i.e.
8907 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
8908 floating-point types only if -fassociative-math is set. */
8919 /* Fold comparisons against built-in math functions. */
8921 && flag_unsafe_math_optimizations
8923 {
8927 {
8931 }
8932 }
8933 }
8937 {
8938 /* If we are widening one operand of an integer comparison,
8939 see if the other operand is similarly being widened. Perhaps we
8940 can do the comparison in the narrower type. */
8945 /* Or if we are changing signedness. */
8949 }
8951 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8952 constant, we can simplify it. */
8957 {
8961 }
8963 /* Simplify comparison of something with itself. (For IEEE
8964 floating-point, we can only do some of these simplifications.) */
8966 {
8968 {
8983 /* For NE, we can only do this simplification if integer
8984 or we don't honor IEEE floating point NaNs. */
8988 /* ... fall through ... */
8994 }
8995 }
8997 /* If we are comparing an expression that just has comparisons
8998 of two integer values, arithmetic expressions of those comparisons,
8999 and constants, we can simplify it. There are only three cases
9000 to check: the two values can either be equal, the first can be
9001 greater, or the second can be greater. Fold the expression for
9002 those three values. Since each value must be 0 or 1, we have
9003 eight possibilities, each of which corresponds to the constant 0
9004 or 1 or one of the six possible comparisons.
9006 This handles common cases like (a > b) == 0 but also handles
9007 expressions like ((x > y) - (y > x)) > 0, which supposedly
9008 occur in macroized code. */
9011 {
9016 /* Don't handle degenerate cases here; they should already
9017 have been handled anyway. */
9026 {
9030 /* We can't just pass T to eval_subst in case cval1 or cval2
9031 was the same as ARG1. */
9033 tree high_result
9037 arg1);
9038 tree equal_result
9042 arg1);
9043 tree low_result
9047 arg1);
9049 /* All three of these results should be 0 or 1. Confirm they are.
9050 Then use those values to select the proper code to use. */
9055 {
9056 /* Make a 3-bit mask with the high-order bit being the
9057 value for `>', the next for '=', and the low for '<'. */
9061 {
9063 /* Always false. */
9084 /* Always true. */
9086 }
9091 }
9092 }
9093 }
9095 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9096 into a single range test. */
9104 {
9108 }
9110 /* Fold ~X op ~Y as Y op X. */
9113 {
9118 }
9120 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9123 {
9129 }
9132 }
9135 /* Subroutine of fold_binary. Optimize complex multiplications of the
9136 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9137 argument EXPR represents the expression "z" of type TYPE. */
9139 static tree
9141 {
9146 {
9149 }
9151 {
9154 }
9155 else
9156 {
9160 }
9169 }
9172 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9173 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9174 guarantees that P and N have the same least significant log2(M) bits.
9175 N is not otherwise constrained. In particular, N is not normalized to
9176 0 <= N < M as is common. In general, the precise value of P is unknown.
9177 M is chosen as large as possible such that constant N can be determined.
9179 Returns M and sets *RESIDUE to N. */
9181 static unsigned HOST_WIDE_INT
9183 {
9190 {
9193 {
9195 tree offset;
9203 {
9206 else
9207 /* We don't handle more complicated offset expressions. */
9209 }
9210 }
9214 }
9216 {
9229 {
9232 }
9234 {
9237 {
9240 /* Compute the greatest power-of-2 divisor of op1. */
9244 /* If align is non-zero and less than *modulus, replace
9245 *modulus with align., If align is 0, then either op1 is 0
9246 or the greatest power-of-2 divisor of op1 doesn't fit in an
9247 unsigned HOST_WIDE_INT. In either case, no additional
9248 constraint is imposed. */
9253 }
9254 }
9255 }
9257 /* If we get here, we were unable to determine anything useful about the
9258 expression. */
9260 }
9263 /* Fold a binary expression of code CODE and type TYPE with operands
9264 OP0 and OP1. Return the folded expression if folding is
9265 successful. Otherwise, return NULL_TREE. */
9267 tree
9269 {
9283 /* Strip any conversions that don't change the mode. This is
9284 safe for every expression, except for a comparison expression
9285 because its signedness is derived from its operands. So, in
9286 the latter case, only strip conversions that don't change the
9287 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9288 preserved.
9290 Note that this is done as an internal manipulation within the
9291 constant folder, in order to find the simplest representation
9292 of the arguments so that their form can be studied. In any
9293 cases, the appropriate type conversions should be put back in
9294 the tree that will get out of the constant folder. */
9297 {
9300 }
9301 else
9302 {
9305 }
9307 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9308 constant but we can't do arithmetic on them. */
9315 {
9317 {
9318 /* Make sure type and arg0 have the same saturating flag. */
9322 }
9325 else
9329 {
9333 }
9334 }
9336 /* If this is a commutative operation, and ARG0 is a constant, move it
9337 to ARG1 to reduce the number of tests below. */
9342 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9344 First check for cases where an arithmetic operation is applied to a
9345 compound, conditional, or comparison operation. Push the arithmetic
9346 operation inside the compound or conditional to see if any folding
9347 can then be done. Convert comparison to conditional for this purpose.
9348 The also optimizes non-constant cases that used to be done in
9349 expand_expr.
9351 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9352 one of the operands is a comparison and the other is a comparison, a
9353 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9354 code below would make the expression more complex. Change it to a
9355 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9356 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9368 {
9372 boolean_type_node,
9380 }
9384 {
9390 op1));
9399 {
9405 }
9408 {
9414 }
9415 }
9418 {
9420 /* 0 +p index -> (type)index */
9424 /* PTR +p 0 -> PTR */
9428 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9435 /* index +p PTR -> PTR +p index */
9442 /* (PTR +p B) +p A -> PTR +p (B + A) */
9444 {
9445 tree inner;
9453 }
9455 /* PTR_CST +p CST -> CST1 */
9459 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9460 of the array. Loop optimizer sometimes produce this type of
9461 expressions. */
9463 {
9467 }
9472 /* PTR + INT -> (INT)(PTR p+ INT) */
9477 arg0,
9479 /* INT + PTR -> (INT)(PTR p+ INT) */
9484 arg1,
9486 /* A + (-B) -> A - B */
9491 /* (-A) + B -> B - A */
9499 {
9500 /* Convert ~A + 1 to -A. */
9506 /* ~X + X is -1. */
9509 {
9514 {
9517 }
9518 }
9520 /* X + ~X is -1. */
9523 {
9528 {
9531 }
9532 }
9534 /* X + (X / CST) * -CST is X % CST. */
9539 {
9547 }
9548 }
9550 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9551 same or one. Make sure type is not saturating.
9552 fold_plusminus_mult_expr will re-associate. */
9557 {
9561 }
9564 {
9568 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9569 with a constant, and the two constants have no bits in common,
9570 we should treat this as a BIT_IOR_EXPR since this may produce more
9571 simplifications. */
9579 {
9582 }
9584 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9585 (plus (plus (mult) (mult)) (foo)) so that we can
9586 take advantage of the factoring cases below. */
9593 {
9599 else
9621 parg1)));
9622 }
9623 }
9624 else
9625 {
9626 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9630 /* Likewise if the operands are reversed. */
9634 /* Convert X + -C into X - C. */
9637 {
9643 }
9645 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9646 to __complex__ ( x, y ). This is not the same for SNaNs or
9647 if signed zeros are involved. */
9651 {
9658 {
9662 {
9668 }
9670 {
9676 }
9677 }
9678 }
9686 /* Convert x+x into x*2.0. */
9692 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9693 We associate floats only if the user has specified
9694 -fassociative-math. */
9698 {
9703 {
9704 tree tree0;
9707 }
9708 }
9709 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9710 We associate floats only if the user has specified
9711 -fassociative-math. */
9715 {
9720 {
9721 tree tree0;
9724 }
9725 }
9726 }
9728 bit_rotate:
9729 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9730 is a rotate of A by C1 bits. */
9731 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9732 is a rotate of A by B bits. */
9733 {
9735 tree rtype;
9744 /* Only create rotates in complete modes. Other cases are not
9745 expanded properly. */
9747 {
9766 {
9774 TYPE_PRECISION
9779 ? LROTATE_EXPR
9782 }
9784 {
9792 TYPE_PRECISION
9797 ? LROTATE_EXPR
9800 }
9801 }
9802 }
9804 associate:
9805 /* In most languages, can't associate operations on floats through
9806 parentheses. Rather than remember where the parentheses were, we
9807 don't associate floats at all, unless the user has specified
9808 -fassociative-math.
9809 And, we need to make sure type is not saturating. */
9813 {
9818 /* Split both trees into variables, constants, and literals. Then
9819 associate each group together, the constants with literals,
9820 then the result with variables. This increases the chances of
9821 literals being recombined later and of generating relocatable
9822 expressions for the sum of a constant and literal. */
9827 /* With undefined overflow we can only associate constants
9828 with one variable. */
9832 {
9840 /* The only case we can still associate with two variables
9841 is if they are the same, modulo negation. */
9844 }
9846 /* Only do something if we found more than two objects. Otherwise,
9847 nothing has changed and we risk infinite recursion. */
9853 {
9854 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9863 /* Preserve the MINUS_EXPR if the negative part of the literal is
9864 greater than the positive part. Otherwise, the multiplicative
9865 folding code (i.e extract_muldiv) may be fooled in case
9866 unsigned constants are subtracted, like in the following
9867 example: ((X*2 + 4) - 8U)/2. */
9869 {
9873 {
9877 }
9878 else
9879 {
9883 }
9884 }
9886 {
9891 else
9892 {
9898 }
9899 }
9904 }
9905 }
9910 /* Pointer simplifications for subtraction, simple reassociations. */
9912 {
9913 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
9916 {
9924 }
9925 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
9927 {
9933 }
9934 }
9935 /* A - (-B) -> A + B */
9939 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9948 /* Convert -A - 1 to ~A. */
9956 /* Convert -1 - A to ~A. */
9962 /* X - (X / CST) * CST is X % CST. */
9975 {
9981 /* Fold A - (A & B) into ~B & A. */
9984 {
9986 {
9991 }
9993 {
9998 }
9999 }
10001 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10002 any power of 2 minus 1. */
10007 {
10013 {
10017 }
10018 }
10019 }
10021 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10025 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10026 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10027 (-ARG1 + ARG0) reduces to -ARG1. */
10031 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10032 __complex__ ( x, -y ). This is not the same for SNaNs or if
10033 signed zeros are involved. */
10037 {
10044 {
10048 {
10050 arg1r ? arg1r
10055 }
10057 {
10061 arg1i ? arg1i
10064 }
10065 }
10066 }
10068 /* Fold &x - &x. This can happen from &x.foo - &x.
10069 This is unsafe for certain floats even in non-IEEE formats.
10070 In IEEE, it is unsafe because it does wrong for NaNs.
10071 Also note that operand_equal_p is always false if an operand
10072 is volatile. */
10078 /* A - B -> A + (-B) if B is easily negatable. */
10081 /* Avoid this transformation if B is a positive REAL_CST. */
10089 /* Try folding difference of addresses. */
10090 {
10091 HOST_WIDE_INT diff;
10097 }
10099 /* Fold &a[i] - &a[j] to i-j. */
10104 {
10109 {
10117 }
10118 }
10126 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10127 same or one. Make sure type is not saturating.
10128 fold_plusminus_mult_expr will re-associate. */
10133 {
10137 }
10142 /* (-A) * (-B) -> A * B */
10153 {
10158 /* Transform x * -1 into -x. Make sure to do the negation
10159 on the original operand with conversions not stripped
10160 because we can only strip non-sign-changing conversions. */
10163 /* Transform x * -C into -x * C if x is easily negatable. */
10172 /* (a * (1 << b)) is (a << b) */
10182 /* (A + A) * C -> A * 2 * C */
10197 {
10200 "occur when simplifying "
10202 WARN_STRICT_OVERFLOW_MISC);
10204 }
10206 /* Optimize z * conj(z) for integer complex numbers. */
10213 }
10214 else
10215 {
10216 /* Maybe fold x * 0 to 0. The expressions aren't the same
10217 when x is NaN, since x * 0 is also NaN. Nor are they the
10218 same in modes with signed zeros, since multiplying a
10219 negative value by 0 gives -0, not +0. */
10224 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10229 /* Transform x * -1.0 into -x. */
10234 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10235 the result for floating point types due to rounding so it is applied
10236 only if -fassociative-math was specify. */
10241 {
10247 }
10249 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10251 {
10254 {
10257 }
10258 }
10260 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10261 This is not the same for NaNs or if signed zeros are
10262 involved. */
10268 {
10280 }
10282 /* Optimize z * conj(z) for floating point complex numbers.
10283 Guarded by flag_unsafe_math_optimizations as non-finite
10284 imaginary components don't produce scalar results. */
10295 {
10299 /* Optimizations of root(...)*root(...). */
10301 {
10306 /* Optimize sqrt(x)*sqrt(x) as x. */
10312 /* Optimize root(x)*root(y) as root(x*y). */
10316 }
10318 /* Optimize expN(x)*expN(y) as expN(x+y). */
10320 {
10326 }
10328 /* Optimizations of pow(...)*pow(...). */
10332 {
10338 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10340 {
10344 }
10346 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10348 {
10352 }
10353 }
10355 /* Optimize tan(x)*cos(x) as sin(x). */
10364 {
10369 }
10371 /* Optimize x*pow(x,c) as pow(x,c+1). */
10375 {
10381 {
10383 REAL_VALUE_TYPE c;
10384 tree arg;
10390 }
10391 }
10393 /* Optimize pow(x,c)*x as pow(x,c+1). */
10397 {
10403 {
10405 REAL_VALUE_TYPE c;
10406 tree arg;
10412 }
10413 }
10415 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10418 {
10422 {
10425 }
10426 }
10427 }
10428 }
10432 bit_ior:
10440 /* ~X | X is -1. */
10443 {
10447 }
10449 /* X | ~X is -1. */
10452 {
10456 }
10458 /* Canonicalize (X & C1) | C2. */
10462 {
10470 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10475 {
10479 }
10480 else
10481 {
10485 }
10487 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10492 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10493 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10494 mode which allows further optimizations. */
10504 {
10505 unsigned HOST_WIDE_INT mask
10509 {
10513 }
10514 }
10521 arg1);
10522 }
10524 /* (X & Y) | Y is (X, Y). */
10528 /* (X & Y) | X is (Y, X). */
10533 /* X | (X & Y) is (Y, X). */
10538 /* X | (Y & X) is (Y, X). */
10548 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10550 This results in more efficient code for machines without a NAND
10551 instruction. Combine will canonicalize to the first form
10552 which will allow use of NAND instructions provided by the
10553 backend if they exist. */
10556 {
10563 }
10565 /* See if this can be simplified into a rotate first. If that
10566 is unsuccessful continue in the association code. */
10577 /* ~X ^ X is -1. */
10580 {
10584 }
10586 /* X ^ ~X is -1. */
10589 {
10593 }
10595 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10596 with a constant, and the two constants have no bits in common,
10597 we should treat this as a BIT_IOR_EXPR since this may produce more
10598 simplifications. */
10606 {
10609 }
10611 /* (X | Y) ^ X -> Y & ~ X*/
10614 {
10617 arg1);
10621 }
10623 /* (Y | X) ^ X -> Y & ~ X*/
10626 {
10629 arg1);
10633 }
10635 /* X ^ (X | Y) -> Y & ~ X*/
10638 {
10641 arg0);
10645 }
10647 /* X ^ (Y | X) -> Y & ~ X*/
10650 {
10653 arg0);
10657 }
10659 /* Convert ~X ^ ~Y to X ^ Y. */
10666 /* Convert ~X ^ C to X ^ ~C. */
10673 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10680 /* Fold (X & Y) ^ Y as ~X & Y. */
10683 {
10688 }
10689 /* Fold (X & Y) ^ X as ~Y & X. */
10693 {
10698 }
10699 /* Fold X ^ (X & Y) as X & ~Y. */
10702 {
10707 }
10708 /* Fold X ^ (Y & X) as ~Y & X. */
10712 {
10717 }
10719 /* See if this can be simplified into a rotate first. If that
10720 is unsuccessful continue in the association code. */
10731 /* ~X & X is always zero. */
10736 /* X & ~X is always zero. */
10741 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10745 {
10753 }
10755 /* (X | Y) & Y is (X, Y). */
10759 /* (X | Y) & X is (Y, X). */
10764 /* X & (X | Y) is (Y, X). */
10769 /* X & (Y | X) is (Y, X). */
10775 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10779 {
10785 }
10786 /* Fold ~X & 1 as (X & 1) == 0. */
10789 {
10795 }
10797 /* Fold (X ^ Y) & Y as ~X & Y. */
10800 {
10805 }
10806 /* Fold (X ^ Y) & X as ~Y & X. */
10810 {
10815 }
10816 /* Fold X & (X ^ Y) as X & ~Y. */
10819 {
10824 }
10825 /* Fold X & (Y ^ X) as ~Y & X. */
10829 {
10834 }
10839 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10842 {
10843 unsigned int prec
10850 }
10852 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10854 This results in more efficient code for machines without a NOR
10855 instruction. Combine will canonicalize to the first form
10856 which will allow use of NOR instructions provided by the
10857 backend if they exist. */
10860 {
10867 }
10869 /* If arg0 is derived from the address of an object or function, we may
10870 be able to fold this expression using the object or function's
10871 alignment. */
10873 {
10879 /* This works because modulus is a power of 2. If this weren't the
10880 case, we'd have to replace it by its greatest power-of-2
10881 divisor: modulus & -modulus. */
10884 }
10886 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
10887 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
10888 if the new mask might be further optimized. */
10897 {
10899 unsigned HOST_WIDE_INT mask
10909 {
10912 /* See if more bits can be proven as zero because of
10913 zero extension. */
10916 {
10921 {
10923 /* See if we can shorten the right shift. */
10926 }
10927 }
10931 /* For arithmetic shift if sign bit could be set, zerobits
10932 can contain actually sign bits, so no transformation is
10933 possible, unless MASK masks them all away. In that
10934 case the shift needs to be converted into logical shift. */
10937 {
10940 else
10942 }
10943 }
10945 /* ((X << 16) & 0xff00) is (X, 0). */
10951 {
10954 /* Only do the transformation if NEWMASK is some integer
10955 mode's mask. */
10962 {
10964 {
10970 }
10971 else
10975 newmask));
10976 }
10977 }
10978 }
10983 /* Don't touch a floating-point divide by zero unless the mode
10984 of the constant can represent infinity. */
10990 /* Optimize A / A to 1.0 if we don't care about
10991 NaNs or Infinities. Skip the transformation
10992 for non-real operands. */
10997 {
11001 }
11003 /* The complex version of the above A / A optimization. */
11006 {
11010 {
11012 /* omit_two_operands will call fold_convert for us. */
11014 }
11015 }
11017 /* (-A) / (-B) -> A / B */
11027 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11032 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11037 /* If ARG1 is a constant, we can convert this to a multiply by the
11038 reciprocal. This does not have the same rounding properties,
11039 so only do this if -freciprocal-math. We can actually
11040 always safely do it if ARG1 is a power of two, but it's hard to
11041 tell if it is or not in a portable manner. */
11043 {
11048 /* Find the reciprocal if optimizing and the result is exact. */
11050 {
11051 REAL_VALUE_TYPE r;
11054 {
11058 }
11059 }
11060 }
11061 /* Convert A/B/C to A/(B*C). */
11068 /* Convert A/(B/C) to (A/B)*C. */
11076 /* Convert C1/(X*C2) into (C1/C2)/X. */
11081 {
11087 }
11090 {
11094 /* Optimize sin(x)/cos(x) as tan(x). */
11100 {
11105 }
11107 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11113 {
11117 {
11121 }
11122 }
11124 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11125 NaNs or Infinities. */
11129 {
11136 {
11141 }
11142 }
11144 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11145 NaNs or Infinities. */
11149 {
11156 {
11160 {
11164 tmp);
11165 }
11166 }
11167 }
11169 /* Optimize pow(x,c)/x as pow(x,c-1). */
11173 {
11179 {
11181 REAL_VALUE_TYPE c;
11182 tree arg;
11188 }
11189 }
11191 /* Optimize a/root(b/c) into a*root(c/b). */
11193 {
11197 {
11206 }
11207 }
11209 /* Optimize x/expN(y) into x*expN(-y). */
11211 {
11216 }
11218 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11222 {
11229 }
11230 }
11235 /* Simplify A / (B << N) where A and B are positive and B is
11236 a power of 2, to A >> (N + log2(B)). */
11241 {
11244 {
11251 WARN_STRICT_OVERFLOW_MISC);
11257 }
11258 }
11260 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11261 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11267 /* Fall thru */
11276 /* X / -1 is -X. */
11283 /* Convert -A / -B to A / B when the type is signed and overflow is
11284 undefined. */
11288 {
11291 "when distributing negation across "
11293 WARN_STRICT_OVERFLOW_MISC);
11297 }
11301 {
11304 "when distributing negation across "
11306 WARN_STRICT_OVERFLOW_MISC);
11309 }
11311 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11312 operation, EXACT_DIV_EXPR.
11314 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11315 At one time others generated faster code, it's not clear if they do
11316 after the last round to changes to the DIV code in expmed.c. */
11325 {
11329 WARN_STRICT_OVERFLOW_MISC);
11331 }
11339 /* X % 1 is always zero, but be sure to preserve any side
11340 effects in X. */
11344 /* X % 0, return X % 0 unchanged so that we can get the
11345 proper warnings and errors. */
11349 /* 0 % X is always zero, but be sure to preserve any side
11350 effects in X. Place this after checking for X == 0. */
11354 /* X % -1 is zero. */
11361 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11362 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11367 {
11369 /* Also optimize A % (C << N) where C is a power of 2,
11370 to A & ((C << N) - 1). */
11375 {
11380 "occur when simplifying "
11382 WARN_STRICT_OVERFLOW_MISC);
11386 }
11387 }
11389 /* X % -C is the same as X % C. */
11396 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11401 /* X % -Y is the same as X % Y. */
11412 {
11416 WARN_STRICT_OVERFLOW_MISC);
11418 }
11429 /* Optimize -1 >> x for arithmetic right shifts. */
11432 /* ... fall through ... */
11435 shift:
11441 /* Since negative shift count is not well-defined,
11442 don't try to compute it in the compiler. */
11446 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11451 {
11455 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11456 being well defined. */
11458 {
11463 else
11465 }
11469 }
11471 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11472 into x & ((unsigned)-1 >> c) for unsigned types. */
11480 {
11483 tree lshift;
11484 tree arg00;
11487 {
11494 }
11495 }
11497 /* Rewrite an LROTATE_EXPR by a constant into an
11498 RROTATE_EXPR by a new constant. */
11500 {
11505 }
11507 /* If we have a rotate of a bit operation with the rotate count and
11508 the second operand of the bit operation both constant,
11509 permute the two operations. */
11521 /* Two consecutive rotates adding up to the precision of the
11522 type can be ignored. */
11533 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11534 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11535 if the latter can be further optimized. */
11540 {
11543 arg1);
11546 arg1);
11550 }
11578 /* Note that the operands of this must be ints
11579 and their values must be 0 or 1.
11580 ("true" is a fixed value perhaps depending on the language.) */
11581 /* If first arg is constant zero, return it. */
11585 /* If either arg is constant true, drop it. */
11589 /* Preserve sequence points. */
11592 /* If second arg is constant zero, result is zero, but first arg
11593 must be evaluated. */
11596 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11597 case will be handled here. */
11601 /* !X && X is always false. */
11605 /* X && !X is always false. */
11610 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11611 means A >= Y && A != MAX, but in this case we know that
11612 A < X <= MAX. */
11616 {
11624 }
11626 truth_andor:
11627 /* We only do these simplifications if we are optimizing. */
11631 /* Check for things like (A || B) && (A || C). We can convert this
11632 to A || (B && C). Note that either operator can be any of the four
11633 truth and/or operations and the transformation will still be
11634 valid. Also note that we only care about order for the
11635 ANDIF and ORIF operators. If B contains side effects, this
11636 might change the truth-value of A. */
11643 {
11663 /* This case if tricky because we must either have commutative
11664 operators or else A10 must not have side-effects. */
11670 a01);
11671 }
11673 /* See if we can build a range comparison. */
11677 /* Check for the possibility of merging component references. If our
11678 lhs is another similar operation, try to merge its rhs with our
11679 rhs. Then try to merge our lhs and rhs. */
11691 /* Note that the operands of this must be ints
11692 and their values must be 0 or true.
11693 ("true" is a fixed value perhaps depending on the language.) */
11694 /* If first arg is constant true, return it. */
11698 /* If either arg is constant zero, drop it. */
11702 /* Preserve sequence points. */
11705 /* If second arg is constant true, result is true, but we must
11706 evaluate first arg. */
11709 /* Likewise for first arg, but note this only occurs here for
11710 TRUTH_OR_EXPR. */
11714 /* !X || X is always true. */
11718 /* X || !X is always true. */
11726 /* If the second arg is constant zero, drop it. */
11729 /* If the second arg is constant true, this is a logical inversion. */
11731 {
11732 /* Only call invert_truthvalue if operand is a truth value. */
11735 else
11738 }
11739 /* Identical arguments cancel to zero. */
11743 /* !X ^ X is always true. */
11748 /* X ^ !X is always true. */
11761 /* bool_var != 0 becomes bool_var. */
11766 /* bool_var == 1 becomes bool_var. */
11771 /* bool_var != 1 becomes !bool_var. */
11776 /* bool_var == 0 becomes !bool_var. */
11781 /* If this is an equality comparison of the address of two non-weak,
11782 unaliased symbols neither of which are extern (since we do not
11783 have access to attributes for externs), then we know the result. */
11796 {
11797 /* We know that we're looking at the address of two
11798 non-weak, unaliased, static _DECL nodes.
11800 It is both wasteful and incorrect to call operand_equal_p
11801 to compare the two ADDR_EXPR nodes. It is wasteful in that
11802 all we need to do is test pointer equality for the arguments
11803 to the two ADDR_EXPR nodes. It is incorrect to use
11804 operand_equal_p as that function is NOT equivalent to a
11805 C equality test. It can in fact return false for two
11806 objects which would test as equal using the C equality
11807 operator. */
11811 type);
11812 }
11814 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11815 a MINUS_EXPR of a constant, we can convert it into a comparison with
11816 a revised constant as long as no overflow occurs. */
11828 /* Similarly for a NEGATE_EXPR. */
11836 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11845 /* Transform comparisons of the form X +- C CMP X. */
11851 {
11858 else
11861 }
11863 /* If we have X - Y == 0, we can convert that to X == Y and similarly
11864 for !=. Don't do this for ordered comparisons due to overflow. */
11870 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11875 /* If this is an EQ or NE comparison with zero and ARG0 is
11876 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11877 two operations, but the latter can be done in one less insn
11878 on machines that have only two-operand insns or on which a
11879 constant cannot be the first operand. */
11882 {
11887 {
11894 }
11897 {
11904 }
11905 }
11907 /* If this is an NE or EQ comparison of zero against the result of a
11908 signed MOD operation whose second operand is a power of 2, make
11909 the MOD operation unsigned since it is simpler and equivalent. */
11917 {
11927 }
11929 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11930 C1 is a valid shift constant, and C2 is a power of two, i.e.
11931 a single bit. */
11935 == INTEGER_CST
11938 {
11943 /* Check for a valid shift count. */
11946 {
11950 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11951 can be rewritten as (X & (C2 << C1)) != 0. */
11953 {
11957 }
11958 /* Otherwise, for signed (arithmetic) shifts,
11959 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11960 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11964 /* Otherwise, of unsigned (logical) shifts,
11965 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11966 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11967 else
11971 arg000);
11972 }
11973 }
11975 /* If this is an NE comparison of zero with an AND of one, remove the
11976 comparison since the AND will give the correct value. */
11983 /* If we have (A & C) == C where C is a power of 2, convert this into
11984 (A & C) != 0. Similarly for NE_EXPR. */
11990 integer_zero_node));
11992 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
11993 bit, then fold the expression into A < 0 or A >= 0. */
11998 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
11999 Similarly for NE_EXPR. */
12003 {
12012 }
12014 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12015 Similarly for NE_EXPR. */
12019 {
12026 }
12028 /* Optimize comparisons of strlen vs zero to a compare of the
12029 first character of the string vs zero. To wit,
12030 strlen(ptr) == 0 => *ptr == 0
12031 strlen(ptr) != 0 => *ptr != 0
12032 Other cases should reduce to one of these two (or a constant)
12033 due to the return value of strlen being unsigned. */
12036 {
12044 {
12048 }
12049 }
12051 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12052 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12056 {
12063 {
12065 {
12068 }
12071 }
12072 }
12074 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12080 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12085 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12092 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12100 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12101 (X & C) == 0 when C is a single bit. */
12106 {
12112 }
12114 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12115 constant C is a power of two, i.e. a single bit. */
12122 {
12126 }
12128 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12129 when is C is a power of two, i.e. a single bit. */
12136 {
12142 }
12146 {
12149 }
12151 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12158 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12161 {
12173 arg01),
12181 arg01),
12189 arg00),
12197 arg00),
12199 }
12203 {
12210 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12211 operand_equal_p guarantees no side-effects so we don't need
12212 to use omit_one_operand on Z. */
12222 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12229 arg10);
12230 }
12232 /* Attempt to simplify equality/inequality comparisons of complex
12233 values. Only lower the comparison if the result is known or
12234 can be simplified to a single scalar comparison. */
12239 {
12244 {
12247 }
12248 else
12249 {
12252 }
12255 {
12258 }
12259 else
12260 {
12263 }
12267 {
12269 {
12274 }
12275 else
12276 {
12281 }
12282 }
12286 {
12288 {
12293 }
12294 else
12295 {
12300 }
12301 }
12302 }
12314 /* Transform comparisons of the form X +- C CMP X. */
12321 {
12328 else
12331 /* (X - c) > X becomes false. */
12335 {
12339 "occur when assuming that (X - c) > X "
12341 WARN_STRICT_OVERFLOW_ALL);
12343 }
12345 /* Likewise (X + c) < X becomes false. */
12349 {
12353 "occur when assuming that "
12355 WARN_STRICT_OVERFLOW_ALL);
12357 }
12359 /* Convert (X - c) <= X to true. */
12364 {
12368 "occur when assuming that "
12370 WARN_STRICT_OVERFLOW_ALL);
12372 }
12374 /* Convert (X + c) >= X to true. */
12379 {
12383 "occur when assuming that "
12385 WARN_STRICT_OVERFLOW_ALL);
12387 }
12390 {
12391 /* Convert X + c > X and X - c < X to true for integers. */
12395 {
12398 "not occur when assuming that "
12400 WARN_STRICT_OVERFLOW_ALL);
12402 }
12407 {
12410 "not occur when assuming that "
12412 WARN_STRICT_OVERFLOW_ALL);
12414 }
12416 /* Convert X + c <= X and X - c >= X to false for integers. */
12420 {
12423 "not occur when assuming that "
12425 WARN_STRICT_OVERFLOW_ALL);
12427 }
12432 {
12435 "not occur when assuming that "
12437 WARN_STRICT_OVERFLOW_ALL);
12439 }
12440 }
12441 }
12443 /* Comparisons with the highest or lowest possible integer of
12444 the specified precision will have known values. */
12445 {
12453 {
12454 HOST_WIDE_INT signed_max_hi;
12459 {
12466 {
12470 }
12471 else
12472 {
12476 }
12477 }
12478 else
12479 {
12488 {
12491 }
12492 else
12493 {
12496 }
12497 }
12502 {
12515 /* The GE_EXPR and LT_EXPR cases above are not normally
12516 reached because of previous transformations. */
12520 }
12522 == max_hi
12525 {
12531 arg1);
12537 arg1);
12540 }
12542 == min_hi
12545 {
12560 }
12562 == min_hi
12565 {
12570 arg1);
12575 arg1);
12578 }
12583 /* We will flip the signedness of the comparison operator
12584 associated with the mode of arg1, so the sign bit is
12585 specified by this mode. Check that arg1 is the signed
12586 max associated with this sign bit. */
12588 /* signed_type does not work on pointer types. */
12590 {
12591 /* The following case also applies to X < signed_max+1
12592 and X >= signed_max+1 because previous transformations. */
12594 {
12595 tree st;
12600 }
12601 }
12602 }
12603 }
12605 /* If we are comparing an ABS_EXPR with a constant, we can
12606 convert all the cases into explicit comparisons, but they may
12607 well not be faster than doing the ABS and one comparison.
12608 But ABS (X) <= C is a range comparison, which becomes a subtraction
12609 and a comparison, and is probably faster. */
12623 /* Convert ABS_EXPR<x> >= 0 to true. */
12630 {
12633 "when simplifying comparison of "
12635 WARN_STRICT_OVERFLOW_CONDITIONAL);
12637 }
12639 /* Convert ABS_EXPR<x> < 0 to false. */
12644 {
12647 "when simplifying comparison of "
12649 WARN_STRICT_OVERFLOW_CONDITIONAL);
12651 }
12653 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12654 and similarly for >= into !=. */
12669 return
12688 {
12692 }
12694 /* If the first operand is NaN, the result is constant. */
12698 {
12700 ? integer_zero_node
12703 }
12705 /* If the second operand is NaN, the result is constant. */
12709 {
12711 ? integer_zero_node
12714 }
12716 /* Simplify unordered comparison of something with itself. */
12722 && !flag_trapping_math
12726 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12727 {
12738 }
12743 /* When pedantic, a compound expression can be neither an lvalue
12744 nor an integer constant expression. */
12747 /* Don't let (0, 0) be null pointer constant. */
12761 /* An ASSERT_EXPR should never be passed to fold_binary. */
12767 }
12769 /* Callback for walk_tree, looking for LABEL_EXPR.
12770 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12771 Do not check the sub-tree of GOTO_EXPR. */
12773 static tree
12777 {
12779 {
12784 /* no break */
12787 }
12788 }
12790 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12791 accessible from outside the sub-tree. Returns NULL_TREE if no
12792 addressable label is found. */
12794 static bool
12796 {
12798 }
12800 /* Fold a ternary expression of code CODE and type TYPE with operands
12801 OP0, OP1, and OP2. Return the folded expression if folding is
12802 successful. Otherwise, return NULL_TREE. */
12804 tree
12806 {
12807 tree tem;
12814 /* Strip any conversions that don't change the mode. This is safe
12815 for every expression, except for a comparison expression because
12816 its signedness is derived from its operands. So, in the latter
12817 case, only strip conversions that don't change the signedness.
12819 Note that this is done as an internal manipulation within the
12820 constant folder, in order to find the simplest representation of
12821 the arguments so that their form can be studied. In any cases,
12822 the appropriate type conversions should be put back in the tree
12823 that will get out of the constant folder. */
12825 {
12828 }
12831 {
12834 }
12837 {
12841 {
12847 }
12851 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12852 so all simple results must be passed through pedantic_non_lvalue. */
12854 {
12857 /* Only optimize constant conditions when the selected branch
12858 has the same type as the COND_EXPR. This avoids optimizing
12859 away "c ? x : throw", where the throw has a void type.
12860 Avoid throwing away that operand which contains label. */
12867 }
12871 /* If we have A op B ? A : C, we may be able to convert this to a
12872 simpler expression, depending on the operation and the values
12873 of B and C. Signed zeros prevent all of these transformations,
12874 for reasons given above each one.
12876 Also try swapping the arguments and inverting the conditional. */
12881 {
12885 }
12889 op2,
12892 {
12895 {
12899 }
12900 }
12902 /* If the second operand is simpler than the third, swap them
12903 since that produces better jump optimization results. */
12906 {
12907 /* See if this can be inverted. If it can't, possibly because
12908 it was a floating-point inequality comparison, don't do
12909 anything. */
12913 }
12915 /* Convert A ? 1 : 0 to simply A. */
12918 /* If we try to convert OP0 to our type, the
12919 call to fold will try to move the conversion inside
12920 a COND, which will recurse. In that case, the COND_EXPR
12921 is probably the best choice, so leave it alone. */
12925 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12926 over COND_EXPR in cases such as floating point comparisons. */
12933 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12938 {
12939 /* sign_bit_p only checks ARG1 bits within A's precision.
12940 If <sign bit of A> has wider type than A, bits outside
12941 of A's precision in <sign bit of A> need to be checked.
12942 If they are all 0, this optimization needs to be done
12943 in unsigned A's type, if they are all 1 in signed A's type,
12944 otherwise this can't be done. */
12949 {
12951 HOST_WIDE_INT mask_hi;
12953 tree tem_type;
12961 {
12965 }
12966 else
12967 {
12971 }
12973 {
12977 }
12978 else
12984 {
12987 }
12990 {
12993 }
12994 else
12996 }
13003 arg1)));
13004 }
13006 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13007 already handled above. */
13012 {
13021 }
13023 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13024 is probably obsolete because the first operand should be a
13025 truth value (that's why we have the two cases above), but let's
13026 leave it in until we can confirm this for all front-ends. */
13037 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13043 arg1);
13045 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13049 {
13050 /* Only perform transformation if ARG0 is easily inverted. */
13055 arg1);
13056 }
13058 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13062 {
13063 /* Only perform transformation if ARG0 is easily inverted. */
13068 op2);
13069 }
13071 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13077 op2);
13082 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13083 of fold_ternary on them. */
13090 {
13099 {
13104 else
13105 {
13107 tree value;
13111 }
13116 else
13118 }
13119 }
13121 /* A bit-field-ref that referenced the full argument can be stripped. */
13132 }
13134 /* Perform constant folding and related simplification of EXPR.
13135 The related simplifications include x*1 => x, x*0 => 0, etc.,
13136 and application of the associative law.
13137 NOP_EXPR conversions may be removed freely (as long as we
13138 are careful not to change the type of the overall expression).
13139 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13140 but we can constant-fold them if they have constant operands. */
13142 #ifdef ENABLE_FOLD_CHECKING
13143 # define fold(x) fold_1 (x)
13145 static
13146 #endif
13147 tree
13149 {
13153 tree tem;
13155 /* Return right away if a constant. */
13159 /* CALL_EXPR-like objects with variable numbers of operands are
13160 treated specially. */
13162 {
13164 {
13167 }
13169 }
13172 {
13177 {
13195 }
13196 }
13199 {
13201 {
13208 {
13213 /* Find a matching index by means of a binary search. */
13215 {
13231 else
13233 }
13234 }
13237 }
13245 }
13247 #ifdef ENABLE_FOLD_CHECKING
13248 #undef fold
13254 /* When --enable-checking=fold, compute a digest of expr before
13255 and after actual fold call to see if fold did not accidentally
13256 change original expr. */
13258 tree
13260 {
13261 tree ret;
13264 htab_t ht;
13283 }
13285 void
13287 {
13290 htab_t ht;
13300 }
13302 static void
13304 {
13306 }
13308 static void
13310 {
13316 recursive_label:
13330 {
13331 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13335 }
13340 {
13341 /* Allow these fields to be modified. */
13342 tree tmp;
13349 {
13352 }
13353 }
13362 {
13365 {
13379 }
13383 {
13396 }
13413 {
13419 }
13424 {
13428 }
13439 {
13442 }
13452 }
13453 }
13455 /* Helper function for outputting the checksum of a tree T. When
13456 debugging with gdb, you can "define mynext" to be "next" followed
13457 by "call debug_fold_checksum (op0)", then just trace down till the
13458 outputs differ. */
13460 void
13462 {
13477 }
13479 #endif
13481 /* Fold a unary tree expression with code CODE of type TYPE with an
13482 operand OP0. Return a folded expression if successful. Otherwise,
13483 return a tree expression with code CODE of type TYPE with an
13484 operand OP0. */
13486 tree
13488 {
13489 tree tem;
13490 #ifdef ENABLE_FOLD_CHECKING
13493 htab_t ht;
13500 #endif
13506 #ifdef ENABLE_FOLD_CHECKING
13514 #endif
13516 }
13518 /* Fold a binary tree expression with code CODE of type TYPE with
13519 operands OP0 and OP1. Return a folded expression if successful.
13520 Otherwise, return a tree expression with code CODE of type TYPE
13521 with operands OP0 and OP1. */
13523 tree
13525 MEM_STAT_DECL)
13526 {
13527 tree tem;
13528 #ifdef ENABLE_FOLD_CHECKING
13534 htab_t ht;
13546 #endif
13552 #ifdef ENABLE_FOLD_CHECKING
13568 #endif
13570 }
13572 /* Fold a ternary tree expression with code CODE of type TYPE with
13573 operands OP0, OP1, and OP2. Return a folded expression if
13574 successful. Otherwise, return a tree expression with code CODE of
13575 type TYPE with operands OP0, OP1, and OP2. */
13577 tree
13579 MEM_STAT_DECL)
13580 {
13581 tree tem;
13582 #ifdef ENABLE_FOLD_CHECKING
13590 htab_t ht;
13607 #endif
13614 #ifdef ENABLE_FOLD_CHECKING
13638 #endif
13640 }
13642 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13643 arguments in ARGARRAY, and a null static chain.
13644 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13645 of type TYPE from the given operands as constructed by build_call_array. */
13647 tree
13649 {
13650 tree tem;
13651 #ifdef ENABLE_FOLD_CHECKING
13657 htab_t ht;
13671 #endif
13675 #ifdef ENABLE_FOLD_CHECKING
13692 #endif
13694 }
13696 /* Perform constant folding and related simplification of initializer
13697 expression EXPR. These behave identically to "fold_buildN" but ignore
13698 potential run-time traps and exceptions that fold must preserve. */
13700 #define START_FOLD_INIT \
13701 int saved_signaling_nans = flag_signaling_nans;\
13702 int saved_trapping_math = flag_trapping_math;\
13703 int saved_rounding_math = flag_rounding_math;\
13704 int saved_trapv = flag_trapv;\
13705 int saved_folding_initializer = folding_initializer;\
13706 flag_signaling_nans = 0;\
13707 flag_trapping_math = 0;\
13708 flag_rounding_math = 0;\
13709 flag_trapv = 0;\
13710 folding_initializer = 1;
13712 #define END_FOLD_INIT \
13713 flag_signaling_nans = saved_signaling_nans;\
13714 flag_trapping_math = saved_trapping_math;\
13715 flag_rounding_math = saved_rounding_math;\
13716 flag_trapv = saved_trapv;\
13717 folding_initializer = saved_folding_initializer;
13719 tree
13721 {
13722 tree result;
13723 START_FOLD_INIT;
13727 END_FOLD_INIT;
13729 }
13731 tree
13733 {
13734 tree result;
13735 START_FOLD_INIT;
13739 END_FOLD_INIT;
13741 }
13743 tree
13745 tree op2)
13746 {
13747 tree result;
13748 START_FOLD_INIT;
13752 END_FOLD_INIT;
13754 }
13756 tree
13759 {
13760 tree result;
13761 START_FOLD_INIT;
13765 END_FOLD_INIT;
13767 }
13769 #undef START_FOLD_INIT
13770 #undef END_FOLD_INIT
13772 /* Determine if first argument is a multiple of second argument. Return 0 if
13773 it is not, or we cannot easily determined it to be.
13775 An example of the sort of thing we care about (at this point; this routine
13776 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13777 fold cases do now) is discovering that
13779 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13781 is a multiple of
13783 SAVE_EXPR (J * 8)
13785 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13787 This code also handles discovering that
13789 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13791 is a multiple of 8 so we don't have to worry about dealing with a
13792 possible remainder.
13794 Note that we *look* inside a SAVE_EXPR only to determine how it was
13795 calculated; it is not safe for fold to do much of anything else with the
13796 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13797 at run time. For example, the latter example above *cannot* be implemented
13798 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13799 evaluation time of the original SAVE_EXPR is not necessarily the same at
13800 the time the new expression is evaluated. The only optimization of this
13801 sort that would be valid is changing
13803 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13805 divided by 8 to
13807 SAVE_EXPR (I) * SAVE_EXPR (J)
13809 (where the same SAVE_EXPR (J) is used in the original and the
13810 transformed version). */
13812 int
13814 {
13822 {
13824 /* Bitwise and provides a power of two multiple. If the mask is
13825 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13828 /* FALLTHRU */
13841 {
13845 /* const_binop may not detect overflow correctly,
13846 so check for it explicitly here. */
13852 size_one_node,
13856 }
13860 /* Can't handle conversions from non-integral or wider integral type. */
13866 /* .. fall through ... */
13883 }
13884 }
13886 /* Return true if CODE or TYPE is known to be non-negative. */
13888 static bool
13890 {
13893 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13894 have a signed:1 type (where the value is -1 and 0). */
13897 }
13899 /* Return true if (CODE OP0) is known to be non-negative. If the return
13900 value is based on the assumption that signed overflow is undefined,
13901 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13902 *STRICT_OVERFLOW_P. */
13904 bool
13907 {
13912 {
13914 /* We can't return 1 if flag_wrapv is set because
13915 ABS_EXPR<INT_MIN> = INT_MIN. */
13919 {
13922 }
13929 strict_overflow_p);
13932 {
13937 {
13940 strict_overflow_p);
13942 {
13946 strict_overflow_p);
13947 }
13948 }
13950 {
13953 strict_overflow_p);
13957 }
13958 }
13963 }
13965 /* We don't know sign of `t', so be conservative and return false. */
13967 }
13969 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13970 value is based on the assumption that signed overflow is undefined,
13971 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13972 *STRICT_OVERFLOW_P. */
13974 bool
13977 {
13982 {
13987 strict_overflow_p)
13989 strict_overflow_p));
13991 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13992 both unsigned and at least 2 bits shorter than the result. */
13996 {
14001 {
14005 }
14006 }
14011 {
14012 /* x * x for floating point x is always non-negative. */
14016 strict_overflow_p)
14018 strict_overflow_p));
14019 }
14021 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14022 both unsigned and their total bits is shorter than the result. */
14026 {
14033 }
14039 strict_overflow_p)
14041 strict_overflow_p));
14052 strict_overflow_p)
14054 strict_overflow_p));
14061 strict_overflow_p);
14064 }
14066 /* We don't know sign of `t', so be conservative and return false. */
14068 }
14070 /* Return true if T is known to be non-negative. If the return
14071 value is based on the assumption that signed overflow is undefined,
14072 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14073 *STRICT_OVERFLOW_P. */
14075 bool
14077 {
14082 {
14094 strict_overflow_p)
14096 strict_overflow_p));
14100 }
14101 /* We don't know sign of `t', so be conservative and return false. */
14103 }
14105 /* Return true if T is known to be non-negative. If the return
14106 value is based on the assumption that signed overflow is undefined,
14107 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14108 *STRICT_OVERFLOW_P. */
14110 bool
14113 {
14116 {
14134 /* Always true. */
14138 /* sqrt(-0.0) is -0.0. */
14142 strict_overflow_p);
14175 /* True if the 1st argument is nonnegative. */
14177 strict_overflow_p);
14180 /* True if the 1st OR 2nd arguments are nonnegative. */
14182 strict_overflow_p)
14184 strict_overflow_p)));
14187 /* True if the 1st AND 2nd arguments are nonnegative. */
14189 strict_overflow_p)
14191 strict_overflow_p)));
14194 /* True if the 2nd argument is nonnegative. */
14196 strict_overflow_p);
14199 /* True if the 1st argument is nonnegative or the second
14200 argument is an even integer. */
14205 strict_overflow_p);
14208 /* True if the 1st argument is nonnegative or the second
14209 argument is an even integer valued real. */
14211 {
14212 REAL_VALUE_TYPE c;
14213 HOST_WIDE_INT n;
14218 {
14219 REAL_VALUE_TYPE cint;
14224 }
14225 }
14227 strict_overflow_p);
14231 }
14233 type);
14234 }
14236 /* Return true if T is known to be non-negative. If the return
14237 value is based on the assumption that signed overflow is undefined,
14238 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14239 *STRICT_OVERFLOW_P. */
14241 bool
14243 {
14249 {
14251 {
14255 /* If the initializer is non-void, then it's a normal expression
14256 that will be assigned to the slot. */
14260 /* Otherwise, the initializer sets the slot in some way. One common
14261 way is an assignment statement at the end of the initializer. */
14263 {
14271 else
14273 }
14277 strict_overflow_p);
14280 }
14283 {
14289 arg0,
14290 arg1,
14291 strict_overflow_p);
14292 }
14296 strict_overflow_p);
14299 strict_overflow_p);
14302 strict_overflow_p);
14307 }
14309 /* We don't know sign of `t', so be conservative and return false. */
14311 }
14313 /* Return true if T is known to be non-negative. If the return
14314 value is based on the assumption that signed overflow is undefined,
14315 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14316 *STRICT_OVERFLOW_P. */
14318 bool
14320 {
14327 {
14334 strict_overflow_p);
14340 strict_overflow_p);
14349 }
14352 {
14360 strict_overflow_p);
14365 strict_overflow_p);
14380 }
14381 }
14383 /* Return true if `t' is known to be non-negative. Handle warnings
14384 about undefined signed overflow. */
14386 bool
14388 {
14395 "determining that expression is always "
14397 WARN_STRICT_OVERFLOW_MISC);
14399 }
14402 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14403 For floating point we further ensure that T is not denormal.
14404 Similar logic is present in nonzero_address in rtlanal.h.
14406 If the return value is based on the assumption that signed overflow
14407 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14408 change *STRICT_OVERFLOW_P. */
14410 bool
14413 {
14415 {
14418 strict_overflow_p);
14421 {
14427 strict_overflow_p));
14428 }
14433 strict_overflow_p);
14437 }
14440 }
14442 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14443 For floating point we further ensure that T is not denormal.
14444 Similar logic is present in nonzero_address in rtlanal.h.
14446 If the return value is based on the assumption that signed overflow
14447 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14448 change *STRICT_OVERFLOW_P. */
14450 bool
14452 tree type,
14453 tree op0,
14455 {
14458 {
14462 {
14463 /* With the presence of negative values it is hard
14464 to say something. */
14471 /* One of operands must be positive and the other non-negative. */
14472 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14473 overflows, on a twos-complement machine the sum of two
14474 nonnegative numbers can never be zero. */
14476 strict_overflow_p)
14478 strict_overflow_p));
14479 }
14484 {
14486 strict_overflow_p)
14488 strict_overflow_p))
14489 {
14492 }
14493 }
14502 {
14505 }
14512 {
14516 /* When both operands are nonzero, then MAX must be too. */
14518 strict_overflow_p))
14521 /* MAX where operand 0 is positive is positive. */
14523 strict_overflow_p);
14524 }
14525 /* MAX where operand 1 is positive is positive. */
14530 {
14534 }
14539 strict_overflow_p)
14541 strict_overflow_p));
14545 }
14548 }
14550 /* Return true when T is an address and is known to be nonzero.
14551 For floating point we further ensure that T is not denormal.
14552 Similar logic is present in nonzero_address in rtlanal.h.
14554 If the return value is based on the assumption that signed overflow
14555 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14556 change *STRICT_OVERFLOW_P. */
14558 bool
14560 {
14563 {
14568 {
14574 /* Weak declarations may link to NULL. */
14578 /* Constants are never weak. */
14583 }
14591 {
14595 }
14600 }
14602 }
14604 /* Return true when T is an address and is known to be nonzero.
14605 For floating point we further ensure that T is not denormal.
14606 Similar logic is present in nonzero_address in rtlanal.h.
14608 If the return value is based on the assumption that signed overflow
14609 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14610 change *STRICT_OVERFLOW_P. */
14612 bool
14614 {
14618 /* Doing something useful for floating point would need more work. */
14624 {
14627 strict_overflow_p);
14633 strict_overflow_p);
14641 }
14644 {
14647 strict_overflow_p);
14655 strict_overflow_p);
14672 strict_overflow_p);
14676 strict_overflow_p);
14683 }
14685 }
14687 /* Return true when T is an address and is known to be nonzero.
14688 Handle warnings about undefined signed overflow. */
14690 bool
14692 {
14699 "determining that expression is always "
14701 WARN_STRICT_OVERFLOW_MISC);
14703 }
14705 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14706 attempt to fold the expression to a constant without modifying TYPE,
14707 OP0 or OP1.
14709 If the expression could be simplified to a constant, then return
14710 the constant. If the expression would not be simplified to a
14711 constant, then return NULL_TREE. */
14713 tree
14715 {
14718 }
14720 /* Given the components of a unary expression CODE, TYPE and OP0,
14721 attempt to fold the expression to a constant without modifying
14722 TYPE or OP0.
14724 If the expression could be simplified to a constant, then return
14725 the constant. If the expression would not be simplified to a
14726 constant, then return NULL_TREE. */
14728 tree
14730 {
14733 }
14735 /* If EXP represents referencing an element in a constant string
14736 (either via pointer arithmetic or array indexing), return the
14737 tree representing the value accessed, otherwise return NULL. */
14739 tree
14741 {
14745 {
14747 tree index;
14748 tree string;
14752 else
14753 {
14757 /* Optimize the special-case of a zero lower bound.
14759 We convert the low_bound to sizetype to avoid some problems
14760 with constant folding. (E.g. suppose the lower bound is 1,
14761 and its mode is QI. Without the conversion,l (ARRAY
14762 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14763 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
14768 }
14781 }
14783 }
14785 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14786 an integer constant, real, or fixed-point constant.
14788 TYPE is the type of the result. */
14790 static tree
14792 {
14796 {
14798 {
14800 HOST_WIDE_INT high;
14808 }
14815 {
14816 FIXED_VALUE_TYPE f;
14821 /* Propagate overflow flags. */
14823 {
14826 }
14830 }
14834 }
14837 }
14839 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14840 an integer constant or real constant.
14842 TYPE is the type of the result. */
14844 tree
14846 {
14850 {
14852 /* If the value is unsigned, then the absolute value is
14853 the same as the ordinary value. */
14856 /* Similarly, if the value is non-negative. */
14859 /* If the value is negative, then the absolute value is
14860 its negation. */
14861 else
14862 {
14864 HOST_WIDE_INT high;
14870 }
14876 else
14882 }
14885 }
14887 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14888 constant. TYPE is the type of the result. */
14890 static tree
14892 {
14902 }
14904 /* Given CODE, a relational operator, the target type, TYPE and two
14905 constant operands OP0 and OP1, return the result of the
14906 relational operation. If the result is not a compile time
14907 constant, then return NULL_TREE. */
14909 static tree
14911 {
14914 /* From here on, the only cases we handle are when the result is
14915 known to be a constant. */
14918 {
14922 /* Handle the cases where either operand is a NaN. */
14924 {
14926 {
14954 }
14957 }
14960 }
14963 {
14967 }
14969 /* Handle equality/inequality of complex constants. */
14971 {
14982 else
14984 }
14986 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14988 To compute GT, swap the arguments and do LT.
14989 To compute GE, do LT and invert the result.
14990 To compute LE, swap the arguments, do LT and invert the result.
14991 To compute NE, do EQ and invert the result.
14993 Therefore, the code below must handle only EQ and LT. */
14996 {
15001 }
15003 /* Note that it is safe to invert for real values here because we
15004 have already handled the one case that it matters. */
15008 {
15011 }
15013 /* Compute a result for LT or EQ if args permit;
15014 Otherwise return T. */
15016 {
15021 else
15023 }
15024 else
15030 }
15032 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15033 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15034 itself. */
15036 tree
15038 {
15039 /* If the expression does not have side effects then we don't have to wrap
15040 it with a cleanup point expression. */
15044 /* If the expression is a return, check to see if the expression inside the
15045 return has no side effects or the right hand side of the modify expression
15046 inside the return. If either don't have side effects set we don't need to
15047 wrap the expression in a cleanup point expression. Note we don't check the
15048 left hand side of the modify because it should always be a return decl. */
15050 {
15057 }
15060 }
15062 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15063 of an indirection through OP0, or NULL_TREE if no simplification is
15064 possible. */
15066 tree
15068 {
15070 tree subtype;
15078 {
15081 /* *&CONST_DECL -> to the value of the const decl. */
15084 /* *&p => p; make sure to handle *&"str"[cst] here. */
15086 {
15090 else
15092 }
15093 /* *(foo *)&fooarray => fooarray[0] */
15096 {
15102 }
15103 /* *(foo *)&complexfoo => __real__ complexfoo */
15107 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15110 {
15114 }
15115 }
15117 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15120 {
15123 tree op00type;
15130 {
15141 }
15142 }
15145 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15148 {
15151 tree op00type;
15158 {
15162 }
15163 }
15165 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15168 {
15169 tree type_domain;
15176 }
15179 }
15181 /* Builds an expression for an indirection through T, simplifying some
15182 cases. */
15184 tree
15186 {
15192 else
15194 }
15196 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15198 tree
15200 {
15205 else
15207 }
15209 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15210 whose result is ignored. The type of the returned tree need not be
15211 the same as the original expression. */
15213 tree
15215 {
15221 {
15232 else
15238 {
15254 }
15259 }
15260 }
15262 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15263 This can only be applied to objects of a sizetype. */
15265 tree
15267 {
15274 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15275 have to do anything. Only do this when we are not given a const,
15276 because in that case, this check is more expensive than just
15277 doing it. */
15279 {
15284 }
15286 /* If divisor is a power of two, simplify this to bit manipulation. */
15288 {
15290 {
15303 {
15304 high++;
15307 }
15311 }
15312 else
15313 {
15314 tree t;
15320 }
15321 }
15322 else
15323 {
15328 }
15331 }
15333 /* Likewise, but round down. */
15335 tree
15337 {
15344 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15345 have to do anything. Only do this when we are not given a const,
15346 because in that case, this check is more expensive than just
15347 doing it. */
15349 {
15354 }
15356 /* If divisor is a power of two, simplify this to bit manipulation. */
15358 {
15359 tree t;
15363 }
15364 else
15365 {
15370 }
15373 }
15375 /* Returns the pointer to the base of the object addressed by EXP and
15376 extracts the information about the offset of the access, storing it
15377 to PBITPOS and POFFSET. */
15379 static tree
15382 {
15383 tree core;
15386 HOST_WIDE_INT bitsize;
15389 {
15394 }
15395 else
15396 {
15400 }
15403 }
15405 /* Returns true if addresses of E1 and E2 differ by a constant, false
15406 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15408 bool
15410 {
15424 {
15434 }
15436 {
15437 /* If only one of the offsets is non-constant, the difference cannot
15438 be a constant. */
15440 }
15441 else
15446 }
15448 /* Simplify the floating point expression EXP when the sign of the
15449 result is not significant. Return NULL_TREE if no simplification
15450 is possible. */
15452 tree
15454 {
15458 {
15493 {
15496 {
15498 /* Strip copysign function call, return the 1st argument. */
15504 /* Strip sign ops from the argument of "odd" math functions. */
15506 {
15510 }
15512 }
15513 }
15518 }
15520 }