| blob | 7cf132b21799e9fa37be7f5d36a8dd723a41ad7c |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /*@@ This file should be rewritten to use an arbitrary precision
23 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
24 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
25 @@ The routines that translate from the ap rep should
26 @@ warn if precision et. al. is lost.
27 @@ This would also make life easier when this technology is used
28 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int_wide, size_binop
31 and force_fit_type_double.
33 fold takes a tree as argument and returns a simplified tree.
35 size_binop takes a tree code for an arithmetic operation
36 and two operands that are trees, and produces a tree for the
37 result, assuming the type comes from `sizetype'.
39 size_int takes an integer value, and creates a tree constant
40 with type from `sizetype'.
42 force_fit_type_double takes a constant, an overflowable flag and a
43 prior overflow indicator. It forces the value to fit the type and
44 sets TREE_OVERFLOW.
46 Note: Since the folders get called on non-gimple code as well as
47 gimple code, we need to handle GIMPLE tuples as well as their
48 corresponding tree equivalents. */
68 /* Nonzero if we are folding constants inside an initializer; zero
69 otherwise. */
72 /* The following constants represent a bit based encoding of GCC's
73 comparison operators. This encoding simplifies transformations
74 on relational comparison operators, such as AND and OR. */
92 };
123 tree);
144 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
145 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
146 and SUM1. Then this yields nonzero if overflow occurred during the
147 addition.
149 Overflow occurs if A and B have the same sign, but A and SUM differ in
150 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
151 sign. */
152 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
153 \f
154 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
155 We do that by representing the two-word integer in 4 words, with only
156 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
157 number. The value of the word is LOWPART + HIGHPART * BASE. */
159 #define LOWPART(x) \
160 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
161 #define HIGHPART(x) \
162 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
163 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
165 /* Unpack a two-word integer into 4 words.
166 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
167 WORDS points to the array of HOST_WIDE_INTs. */
169 static void
171 {
176 }
178 /* Pack an array of 4 words into a two-word integer.
179 WORDS points to the array of words.
180 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
182 static void
185 {
188 }
189 \f
190 /* Force the double-word integer L1, H1 to be within the range of the
191 integer type TYPE. Stores the properly truncated and sign-extended
192 double-word integer in *LV, *HV. Returns true if the operation
193 overflows, that is, argument and result are different. */
195 int
198 {
207 else
210 /* Size types *are* sign extended. */
215 /* First clear all bits that are beyond the type's precision. */
217 ;
220 else
221 {
225 }
227 /* Then do sign extension if necessary. */
233 {
234 /* Sign extend top half? */
238 }
240 {
243 }
244 else
245 {
246 /* Sign extend bottom half? */
248 {
251 }
252 }
257 /* If the value didn't fit, signal overflow. */
259 }
261 /* We force the double-int HIGH:LOW to the range of the type TYPE by
262 sign or zero extending it.
263 OVERFLOWABLE indicates if we are interested
264 in overflow of the value, when >0 we are only interested in signed
265 overflow, for <0 we are interested in any overflow. OVERFLOWED
266 indicates whether overflow has already occurred. CONST_OVERFLOWED
267 indicates whether constant overflow has already occurred. We force
268 T's value to be within range of T's type (by setting to 0 or 1 all
269 the bits outside the type's range). We set TREE_OVERFLOWED if,
270 OVERFLOWED is nonzero,
271 or OVERFLOWABLE is >0 and signed overflow occurs
272 or OVERFLOWABLE is <0 and any overflow occurs
273 We return a new tree node for the extended double-int. The node
274 is shared if no overflow flags are set. */
276 tree
280 {
284 /* Size types *are* sign extended. */
291 /* If we need to set overflow flags, return a new unshared node. */
293 {
297 {
304 }
305 }
307 /* Else build a shared node. */
309 }
310 \f
311 /* Add two doubleword integers with doubleword result.
312 Return nonzero if the operation overflows according to UNSIGNED_P.
313 Each argument is given as two `HOST_WIDE_INT' pieces.
314 One argument is L1 and H1; the other, L2 and H2.
315 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
317 int
322 {
324 HOST_WIDE_INT h;
334 else
336 }
338 /* Negate a doubleword integer with doubleword result.
339 Return nonzero if the operation overflows, assuming it's signed.
340 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
341 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
343 int
346 {
348 {
352 }
353 else
354 {
358 }
359 }
360 \f
361 /* Multiply two doubleword integers with doubleword result.
362 Return nonzero if the operation overflows according to UNSIGNED_P.
363 Each argument is given as two `HOST_WIDE_INT' pieces.
364 One argument is L1 and H1; the other, L2 and H2.
365 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
367 int
372 {
387 {
390 {
392 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
394 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
398 }
400 }
405 /* Unsigned overflow is immediate. */
409 /* Check for signed overflow by calculating the signed representation of the
410 top half of the result; it should agree with the low half's sign bit. */
412 {
415 }
417 {
420 }
422 }
423 \f
424 /* Shift the doubleword integer in L1, H1 left by COUNT places
425 keeping only PREC bits of result.
426 Shift right if COUNT is negative.
427 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
428 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
430 void
434 {
438 {
441 }
447 {
448 /* Shifting by the host word size is undefined according to the
449 ANSI standard, so we must handle this as a special case. */
452 }
454 {
457 }
458 else
459 {
463 }
465 /* Sign extend all bits that are beyond the precision. */
473 ;
475 {
478 }
479 else
480 {
484 }
485 }
487 /* Shift the doubleword integer in L1, H1 right by COUNT places
488 keeping only PREC bits of result. COUNT must be positive.
489 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
490 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
492 void
497 {
500 signmask = (arith
508 {
509 /* Shifting by the host word size is undefined according to the
510 ANSI standard, so we must handle this as a special case. */
513 }
515 {
518 }
519 else
520 {
524 }
526 /* Zero / sign extend all bits that are beyond the precision. */
529 {
532 }
534 ;
536 {
539 }
540 else
541 {
545 }
546 }
547 \f
548 /* Rotate the doubleword integer in L1, H1 left by COUNT places
549 keeping only PREC bits of result.
550 Rotate right if COUNT is negative.
551 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
553 void
557 {
569 }
571 /* Rotate the doubleword integer in L1, H1 left by COUNT places
572 keeping only PREC bits of result. COUNT must be positive.
573 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
575 void
579 {
591 }
592 \f
593 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
594 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
595 CODE is a tree code for a kind of division, one of
596 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
597 or EXACT_DIV_EXPR
598 It controls how the quotient is rounded to an integer.
599 Return nonzero if the operation overflows.
600 UNS nonzero says do unsigned division. */
602 int
605 HOST_WIDE_INT hnum_orig,
607 HOST_WIDE_INT hden_orig,
611 {
627 /* Calculate quotient sign and convert operands to unsigned. */
629 {
631 {
633 /* (minimum integer) / (-1) is the only overflow case. */
637 }
639 {
642 }
643 }
648 /* This unsigned division rounds toward zero. */
651 }
655 /* hden != 0 already checked. */
660 }
670 /* Special code for when the divisor < BASE. */
672 {
673 /* hnum != 0 already checked. */
675 {
679 }
680 }
681 else
682 {
683 /* Full double precision division,
684 with thanks to Don Knuth's "Seminumerical Algorithms". */
688 /* Find the highest nonzero divisor digit. */
691 {
694 }
696 /* Insure that the first digit of the divisor is at least BASE/2.
697 This is required by the quotient digit estimation algorithm. */
704 {
708 }
713 {
718 }
719 }
723 /* Main loop */
725 {
726 /* Guess the next quotient digit, quo_est, by dividing the first
727 two remaining dividend digits by the high order quotient digit.
728 quo_est is never low and is at most 2 high. */
735 else
738 /* Refine quo_est so it's usually correct, and at most one high. */
743 quo_est--;
745 /* Try QUO_EST as the quotient digit, by multiplying the
746 divisor by QUO_EST and subtracting from the remaining dividend.
747 Keep in mind that QUO_EST is the I - 1st digit. */
751 {
757 }
759 /* If quo_est was high by one, then num[i] went negative and
760 we need to correct things. */
762 {
763 quo_est--;
766 {
770 }
773 }
775 /* Store the quotient digit. */
777 }
778 }
782 finish_up:
783 /* If result is negative, make it so. */
787 /* Compute trial remainder: rem = num - (quo * den) */
793 {
802 {
803 /* quo = quo - 1; */
806 }
807 else
814 {
817 }
818 else
824 {
830 /* Get absolute values. */
836 /* If (2 * abs (lrem) >= abs (lden)) */
845 {
847 /* quo = quo - 1; */
850 else
851 /* quo = quo + 1; */
854 }
855 else
857 }
862 }
864 /* Compute true remainder: rem = num - (quo * den) */
869 }
871 /* If ARG2 divides ARG1 with zero remainder, carries out the division
872 of type CODE and returns the quotient.
873 Otherwise returns NULL_TREE. */
875 static tree
877 {
887 /* &obj[0] + -128 really should be compiled as &obj[-8] rather than
888 &obj[some_exotic_number]. */
890 {
894 type);
895 }
896 else
907 }
908 \f
909 /* This is nonzero if we should defer warnings about undefined
910 overflow. This facility exists because these warnings are a
911 special case. The code to estimate loop iterations does not want
912 to issue any warnings, since it works with expressions which do not
913 occur in user code. Various bits of cleanup code call fold(), but
914 only use the result if it has certain characteristics (e.g., is a
915 constant); that code only wants to issue a warning if the result is
916 used. */
920 /* If a warning about undefined overflow is deferred, this is the
921 warning. Note that this may cause us to turn two warnings into
922 one, but that is fine since it is sufficient to only give one
923 warning per expression. */
927 /* If a warning about undefined overflow is deferred, this is the
928 level at which the warning should be emitted. */
932 /* Start deferring overflow warnings. We could use a stack here to
933 permit nested calls, but at present it is not necessary. */
935 void
937 {
939 }
941 /* Stop deferring overflow warnings. If there is a pending warning,
942 and ISSUE is true, then issue the warning if appropriate. STMT is
943 the statement with which the warning should be associated (used for
944 location information); STMT may be NULL. CODE is the level of the
945 warning--a warn_strict_overflow_code value. This function will use
946 the smaller of CODE and the deferred code when deciding whether to
947 issue the warning. CODE may be zero to mean to always use the
948 deferred code. */
950 void
952 {
954 location_t locus;
959 {
965 }
976 /* Use the smallest code level when deciding to issue the
977 warning. */
986 else
989 }
991 /* Stop deferring overflow warnings, ignoring any deferred
992 warnings. */
994 void
996 {
998 }
1000 /* Whether we are deferring overflow warnings. */
1002 bool
1004 {
1006 }
1008 /* This is called when we fold something based on the fact that signed
1009 overflow is undefined. */
1011 static void
1013 {
1016 {
1019 {
1022 }
1023 }
1026 }
1027 \f
1028 /* Return true if the built-in mathematical function specified by CODE
1029 is odd, i.e. -f(x) == f(-x). */
1031 static bool
1033 {
1035 {
1069 }
1071 }
1073 /* Check whether we may negate an integer constant T without causing
1074 overflow. */
1076 bool
1078 {
1081 tree type;
1091 {
1096 }
1097 else
1102 }
1104 /* Determine whether an expression T can be cheaply negated using
1105 the function negate_expr without introducing undefined overflow. */
1107 static bool
1109 {
1110 tree type;
1119 {
1124 /* Check that -CST will not overflow type. */
1150 /* -(A + B) -> (-B) - A. */
1155 /* -(A + B) -> (-A) - B. */
1159 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
1169 /* Fall through. */
1182 /* In general we can't negate A / B, because if A is INT_MIN and
1183 B is 1, we may turn this into INT_MIN / -1 which is undefined
1184 and actually traps on some architectures. But if overflow is
1185 undefined, we can negate, because - (INT_MIN / 1) is an
1186 overflow. */
1194 /* Negate -((double)float) as (double)(-float). */
1196 {
1200 }
1204 /* Negate -f(x) as f(-x). */
1210 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1212 {
1218 }
1223 }
1225 }
1227 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
1228 simplification is possible.
1229 If negate_expr_p would return true for T, NULL_TREE will never be
1230 returned. */
1232 static tree
1234 {
1236 tree tem;
1239 {
1240 /* Convert - (~A) to A + 1. */
1256 /* Two's complement FP formats, such as c4x, may overflow. */
1266 {
1275 }
1297 {
1298 /* -(A + B) -> (-B) - A. */
1302 {
1306 }
1308 /* -(A + B) -> (-A) - B. */
1310 {
1314 }
1315 }
1319 /* - (A - B) -> B - A */
1331 /* Fall through. */
1335 {
1344 }
1352 /* In general we can't negate A / B, because if A is INT_MIN and
1353 B is 1, we may turn this into INT_MIN / -1 which is undefined
1354 and actually traps on some architectures. But if overflow is
1355 undefined, we can negate, because - (INT_MIN / 1) is an
1356 overflow. */
1358 {
1363 {
1370 }
1373 {
1380 }
1381 }
1385 /* Convert -((double)float) into (double)(-float). */
1387 {
1391 }
1395 /* Negate -f(x) as f(-x). */
1398 {
1404 }
1408 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1410 {
1415 {
1422 }
1423 }
1428 }
1431 }
1433 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
1434 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
1435 return NULL_TREE. */
1437 static tree
1439 {
1452 }
1453 \f
1454 /* Split a tree IN into a constant, literal and variable parts that could be
1455 combined with CODE to make IN. "constant" means an expression with
1456 TREE_CONSTANT but that isn't an actual constant. CODE must be a
1457 commutative arithmetic operation. Store the constant part into *CONP,
1458 the literal in *LITP and return the variable part. If a part isn't
1459 present, set it to null. If the tree does not decompose in this way,
1460 return the entire tree as the variable part and the other parts as null.
1462 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
1463 case, we negate an operand that was subtracted. Except if it is a
1464 literal for which we use *MINUS_LITP instead.
1466 If NEGATE_P is true, we are negating all of IN, again except a literal
1467 for which we use *MINUS_LITP instead.
1469 If IN is itself a literal or constant, return it as appropriate.
1471 Note that we do not guarantee that any of the three values will be the
1472 same type as IN, but they will have the same signedness and mode. */
1474 static tree
1477 {
1484 /* Strip any conversions that don't change the machine mode or signedness. */
1493 /* We can associate addition and subtraction together (even
1494 though the C standard doesn't say so) for integers because
1495 the value is not affected. For reals, the value might be
1496 affected, so we can't. */
1499 {
1505 /* First see if either of the operands is a literal, then a constant. */
1518 /* If we haven't dealt with either operand, this is not a case we can
1519 decompose. Otherwise, VAR is either of the ones remaining, if any. */
1524 else
1527 /* Now do any needed negations. */
1534 }
1537 else
1541 {
1548 }
1551 }
1553 /* Re-associate trees split by the above function. T1 and T2 are either
1554 expressions to associate or null. Return the new expression, if any. If
1555 we build an operation, do it in TYPE and with CODE. */
1557 static tree
1559 {
1565 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
1566 try to fold this since we will have infinite recursion. But do
1567 deal with any NEGATE_EXPRs. */
1570 {
1572 {
1581 }
1583 {
1586 }
1590 }
1594 }
1595 \f
1596 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1597 for use in int_const_binop, size_binop and size_diffop. */
1599 static bool
1601 {
1608 {
1617 }
1622 }
1625 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1626 to produce a new constant. Return NULL_TREE if we don't know how
1627 to evaluate CODE at compile-time.
1629 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1631 tree
1633 {
1637 HOST_WIDE_INT hi;
1639 HOST_WIDE_INT garbageh;
1640 tree t;
1643 int is_sizetype
1653 {
1669 /* It's unclear from the C standard whether shifts can overflow.
1670 The following code ignores overflow; perhaps a C standard
1671 interpretation ruling is needed. */
1700 /* This is a shortcut for a common special case. */
1705 {
1711 }
1713 /* ... fall through ... */
1719 {
1722 }
1725 {
1728 }
1735 /* This is a shortcut for a common special case. */
1740 {
1745 }
1747 /* ... fall through ... */
1765 else
1771 else
1777 }
1780 {
1783 /* Propagate overflow flags ourselves. */
1786 {
1789 }
1790 }
1791 else
1797 }
1799 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1800 constant. We assume ARG1 and ARG2 have the same data type, or at least
1801 are the same kind of constant and the same machine mode. Return zero if
1802 combining the constants is not allowed in the current operating mode.
1804 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1806 static tree
1808 {
1809 /* Sanity check for the recursive cases. */
1820 {
1822 REAL_VALUE_TYPE d1;
1823 REAL_VALUE_TYPE d2;
1824 REAL_VALUE_TYPE value;
1825 REAL_VALUE_TYPE result;
1829 /* The following codes are handled by real_arithmetic. */
1831 {
1842 }
1850 /* Don't perform operation if we honor signaling NaNs and
1851 either operand is a NaN. */
1856 /* Don't perform operation if it would raise a division
1857 by zero exception. */
1863 /* If either operand is a NaN, just return it. Otherwise, set up
1864 for floating-point trap; we return an overflow. */
1873 /* Don't constant fold this floating point operation if
1874 the result has overflowed and flag_trapping_math. */
1882 /* Don't constant fold this floating point operation if the
1883 result may dependent upon the run-time rounding mode and
1884 flag_rounding_math is set, or if GCC's software emulation
1885 is unable to accurately represent the result. */
1896 }
1899 {
1900 FIXED_VALUE_TYPE f1;
1901 FIXED_VALUE_TYPE f2;
1902 FIXED_VALUE_TYPE result;
1907 /* The following codes are handled by fixed_arithmetic. */
1909 {
1926 }
1933 /* Propagate overflow flags. */
1935 {
1938 }
1942 }
1945 {
1954 {
1965 notrunc);
1969 notrunc);
1973 {
1974 tree magsquared
1978 notrunc);
1979 tree t1
1983 notrunc);
1984 tree t2
1988 notrunc);
1995 }
2000 }
2004 }
2007 }
2009 /* Create a size type INT_CST node with NUMBER sign extended. KIND
2010 indicates which particular sizetype to create. */
2012 tree
2014 {
2016 }
2017 \f
2018 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2019 is a tree code. The type of the result is taken from the operands.
2020 Both must be equivalent integer types, ala int_binop_types_match_p.
2021 If the operands are constant, so is the result. */
2023 tree
2025 {
2034 /* Handle the special case of two integer constants faster. */
2036 {
2037 /* And some specific cases even faster than that. */
2039 {
2044 }
2046 {
2049 }
2051 {
2054 }
2056 /* Handle general case of two integer constants. */
2058 }
2061 }
2063 /* Given two values, either both of sizetype or both of bitsizetype,
2064 compute the difference between the two values. Return the value
2065 in signed type corresponding to the type of the operands. */
2067 tree
2069 {
2071 tree ctype;
2076 /* If the type is already signed, just do the simple thing. */
2084 else
2087 /* If either operand is not a constant, do the conversions to the signed
2088 type and subtract. The hardware will do the right thing with any
2089 overflow in the subtraction. */
2094 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2095 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2096 overflow) and negate (which can't either). Special-case a result
2097 of zero while we're here. */
2102 else
2106 }
2107 \f
2108 /* A subroutine of fold_convert_const handling conversions of an
2109 INTEGER_CST to another integer type. */
2111 static tree
2113 {
2114 tree t;
2116 /* Given an integer constant, make new constant with new type,
2117 appropriately sign-extended or truncated. */
2120 /* Don't set the overflow when
2121 converting from a pointer, */
2123 /* or to a sizetype with same signedness
2124 and the precision is unchanged.
2125 ??? sizetype is always sign-extended,
2126 but its signedness depends on the
2127 frontend. Thus we see spurious overflows
2128 here if we do not check this. */
2143 }
2145 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2146 to an integer type. */
2148 static tree
2150 {
2152 tree t;
2154 /* The following code implements the floating point to integer
2155 conversion rules required by the Java Language Specification,
2156 that IEEE NaNs are mapped to zero and values that overflow
2157 the target precision saturate, i.e. values greater than
2158 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2159 are mapped to INT_MIN. These semantics are allowed by the
2160 C and C++ standards that simply state that the behavior of
2161 FP-to-integer conversion is unspecified upon overflow. */
2164 REAL_VALUE_TYPE r;
2168 {
2175 }
2177 /* If R is NaN, return zero and show we have an overflow. */
2179 {
2183 }
2185 /* See if R is less than the lower bound or greater than the
2186 upper bound. */
2189 {
2193 {
2197 }
2198 }
2201 {
2204 {
2207 {
2211 }
2212 }
2213 }
2221 }
2223 /* A subroutine of fold_convert_const handling conversions of a
2224 FIXED_CST to an integer type. */
2226 static tree
2228 {
2229 tree t;
2233 /* Right shift FIXED_CST to temp by fbit. */
2237 {
2242 /* Left shift temp to temp_trunc by fbit. */
2247 }
2248 else
2249 {
2254 }
2256 /* If FIXED_CST is negative, we need to round the value toward 0.
2257 By checking if the fractional bits are not zero to add 1 to temp. */
2260 {
2261 double_int one;
2265 }
2267 /* Given a fixed-point constant, make new constant with new type,
2268 appropriately sign-extended or truncated. */
2276 }
2278 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2279 to another floating point type. */
2281 static tree
2283 {
2284 REAL_VALUE_TYPE value;
2285 tree t;
2292 }
2294 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2295 to a floating point type. */
2297 static tree
2299 {
2300 REAL_VALUE_TYPE value;
2301 tree t;
2310 }
2312 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2313 to another fixed-point type. */
2315 static tree
2317 {
2318 FIXED_VALUE_TYPE value;
2319 tree t;
2326 /* Propagate overflow flags. */
2328 {
2331 }
2335 }
2337 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2338 to a fixed-point type. */
2340 static tree
2342 {
2343 FIXED_VALUE_TYPE value;
2344 tree t;
2353 /* Propagate overflow flags. */
2355 {
2358 }
2362 }
2364 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2365 to a fixed-point type. */
2367 static tree
2369 {
2370 FIXED_VALUE_TYPE value;
2371 tree t;
2379 /* Propagate overflow flags. */
2381 {
2384 }
2388 }
2390 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2391 type TYPE. If no simplification can be done return NULL_TREE. */
2393 static tree
2395 {
2400 {
2407 }
2409 {
2416 }
2418 {
2425 }
2427 }
2429 /* Construct a vector of zero elements of vector type TYPE. */
2431 static tree
2433 {
2444 }
2446 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2448 bool
2450 {
2465 {
2484 }
2485 }
2487 /* Convert expression ARG to type TYPE. Used by the middle-end for
2488 simple conversions in preference to calling the front-end's convert. */
2490 tree
2492 {
2494 tree tem;
2508 {
2513 {
2517 }
2522 {
2525 }
2532 {
2536 }
2538 {
2542 }
2544 {
2548 }
2551 {
2569 }
2574 {
2578 }
2581 {
2595 }
2599 {
2609 {
2613 {
2617 }
2625 }
2629 }
2647 }
2648 }
2649 \f
2650 /* Return false if expr can be assumed not to be an lvalue, true
2651 otherwise. */
2653 static bool
2655 {
2656 /* We only need to wrap lvalue tree codes. */
2658 {
2693 /* Assume the worst for front-end tree codes. */
2697 }
2700 }
2702 /* Return an expr equal to X but certainly not valid as an lvalue. */
2704 tree
2706 {
2707 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2708 us. */
2715 }
2717 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2718 Zero means allow extended lvalues. */
2722 /* When pedantic, return an expr equal to X but certainly not valid as a
2723 pedantic lvalue. Otherwise, return X. */
2725 static tree
2727 {
2730 else
2732 }
2733 \f
2734 /* Given a tree comparison code, return the code that is the logical inverse
2735 of the given code. It is not safe to do this for floating-point
2736 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2737 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2739 enum tree_code
2741 {
2746 {
2777 }
2778 }
2780 /* Similar, but return the comparison that results if the operands are
2781 swapped. This is safe for floating-point. */
2783 enum tree_code
2785 {
2787 {
2813 }
2814 }
2817 /* Convert a comparison tree code from an enum tree_code representation
2818 into a compcode bit-based encoding. This function is the inverse of
2819 compcode_to_comparison. */
2821 static enum comparison_code
2823 {
2825 {
2856 }
2857 }
2859 /* Convert a compcode bit-based encoding of a comparison operator back
2860 to GCC's enum tree_code representation. This function is the
2861 inverse of comparison_to_compcode. */
2863 static enum tree_code
2865 {
2867 {
2898 }
2899 }
2901 /* Return a tree for the comparison which is the combination of
2902 doing the AND or OR (depending on CODE) of the two operations LCODE
2903 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2904 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2905 if this makes the transformation invalid. */
2907 tree
2911 {
2918 {
2929 }
2932 {
2933 /* Eliminate unordered comparisons, as well as LTGT and ORD
2934 which are not used unless the mode has NaNs. */
2940 }
2942 {
2943 /* Check that the original operation and the optimized ones will trap
2944 under the same condition. */
2955 /* In a short-circuited boolean expression the LHS might be
2956 such that the RHS, if evaluated, will never trap. For
2957 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2958 if neither x nor y is NaN. (This is a mixed blessing: for
2959 example, the expression above will never trap, hence
2960 optimizing it to x < y would be invalid). */
2965 /* If the comparison was short-circuited, and only the RHS
2966 trapped, we may now generate a spurious trap. */
2971 /* If we changed the conditions that cause a trap, we lose. */
2974 }
2980 else
2983 }
2985 /* Return nonzero if CODE is a tree code that represents a truth value. */
2987 static int
2989 {
2994 }
2995 \f
2996 /* Return nonzero if two operands (typically of the same tree node)
2997 are necessarily equal. If either argument has side-effects this
2998 function returns zero. FLAGS modifies behavior as follows:
3000 If OEP_ONLY_CONST is set, only return nonzero for constants.
3001 This function tests whether the operands are indistinguishable;
3002 it does not test whether they are equal using C's == operation.
3003 The distinction is important for IEEE floating point, because
3004 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3005 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3007 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3008 even though it may hold multiple values during a function.
3009 This is because a GCC tree node guarantees that nothing else is
3010 executed between the evaluation of its "operands" (which may often
3011 be evaluated in arbitrary order). Hence if the operands themselves
3012 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3013 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3014 unset means assuming isochronic (or instantaneous) tree equivalence.
3015 Unless comparing arbitrary expression trees, such as from different
3016 statements, this flag can usually be left unset.
3018 If OEP_PURE_SAME is set, then pure functions with identical arguments
3019 are considered the same. It is used when the caller has other ways
3020 to ensure that global memory is unchanged in between. */
3022 int
3024 {
3025 /* If either is ERROR_MARK, they aren't equal. */
3029 /* If both types don't have the same signedness, then we can't consider
3030 them equal. We must check this before the STRIP_NOPS calls
3031 because they may change the signedness of the arguments. */
3035 /* If both types don't have the same precision, then it is not safe
3036 to strip NOPs. */
3043 /* In case both args are comparisons but with different comparison
3044 code, try to swap the comparison operands of one arg to produce
3045 a match and compare that variant. */
3049 {
3057 }
3060 /* This is needed for conversions and for COMPONENT_REF.
3061 Might as well play it safe and always test this. */
3067 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3068 We don't care about side effects in that case because the SAVE_EXPR
3069 takes care of that for us. In all other cases, two expressions are
3070 equal if they have no side effects. If we have two identical
3071 expressions with side effects that should be treated the same due
3072 to the only side effects being identical SAVE_EXPR's, that will
3073 be detected in the recursive calls below. */
3079 /* Next handle constant cases, those for which we can return 1 even
3080 if ONLY_CONST is set. */
3083 {
3098 {
3099 /* If we do not distinguish between signed and unsigned zero,
3100 consider them equal. */
3103 }
3107 {
3113 {
3115 flags))
3119 }
3122 }
3126 flags)
3128 flags));
3141 }
3146 /* Define macros to test an operand from arg0 and arg1 for equality and a
3147 variant that allows null and views null as being different from any
3148 non-null value. In the latter case, if either is null, the both
3149 must be; otherwise, do the normal comparison. */
3150 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3151 TREE_OPERAND (arg1, N), flags)
3153 #define OP_SAME_WITH_NULL(N) \
3154 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3155 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3158 {
3160 /* Two conversions are equal only if signedness and modes match. */
3162 {
3172 }
3182 /* For commutative ops, allow the other order. */
3190 /* If either of the pointer (or reference) expressions we are
3191 dereferencing contain a side effect, these cannot be equal. */
3197 {
3207 /* Operands 2 and 3 may be null.
3208 Compare the array index by value if it is constant first as we
3209 may have different types but same value here. */
3218 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3219 may be NULL when we're called to compare MEM_EXPRs. */
3229 }
3233 {
3248 /* Otherwise take into account this is a commutative operation. */
3256 }
3260 {
3262 /* If the CALL_EXPRs call different functions, then they
3263 clearly can not be equal. */
3265 flags))
3268 {
3272 else
3276 }
3278 /* Now see if all the arguments are the same. */
3279 {
3290 /* If we get here and both argument lists are exhausted
3291 then the CALL_EXPRs are equal. */
3293 }
3296 }
3299 /* Consider __builtin_sqrt equal to sqrt. */
3307 }
3309 #undef OP_SAME
3310 #undef OP_SAME_WITH_NULL
3311 }
3312 \f
3313 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3314 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3316 When in doubt, return 0. */
3318 static int
3320 {
3332 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3333 and see if the inner values are the same. This removes any
3334 signedness comparison, which doesn't matter here. */
3341 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3342 actual comparison operand, ARG0.
3344 First throw away any conversions to wider types
3345 already present in the operands. */
3354 {
3357 /* Make sure shorter operand is extended the right way
3358 to match the longer operand. */
3364 }
3367 }
3368 \f
3369 /* See if ARG is an expression that is either a comparison or is performing
3370 arithmetic on comparisons. The comparisons must only be comparing
3371 two different values, which will be stored in *CVAL1 and *CVAL2; if
3372 they are nonzero it means that some operands have already been found.
3373 No variables may be used anywhere else in the expression except in the
3374 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3375 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3377 If this is true, return 1. Otherwise, return zero. */
3379 static int
3381 {
3385 /* We can handle some of the tcc_expression cases here. */
3395 {
3396 /* If we've already found a CVAL1 or CVAL2, this expression is
3397 two complex to handle. */
3403 }
3406 {
3429 /* First see if we can handle the first operand, then the second. For
3430 the second operand, we know *CVAL1 can't be zero. It must be that
3431 one side of the comparison is each of the values; test for the
3432 case where this isn't true by failing if the two operands
3433 are the same. */
3442 ;
3446 ;
3447 else
3451 ;
3455 ;
3456 else
3463 }
3464 }
3465 \f
3466 /* ARG is a tree that is known to contain just arithmetic operations and
3467 comparisons. Evaluate the operations in the tree substituting NEW0 for
3468 any occurrence of OLD0 as an operand of a comparison and likewise for
3469 NEW1 and OLD1. */
3471 static tree
3473 {
3478 /* We can handle some of the tcc_expression cases here. */
3486 {
3501 {
3518 }
3519 /* Fall through - ??? */
3522 {
3526 /* We need to check both for exact equality and tree equality. The
3527 former will be true if the operand has a side-effect. In that
3528 case, we know the operand occurred exactly once. */
3541 }
3545 }
3546 }
3547 \f
3548 /* Return a tree for the case when the result of an expression is RESULT
3549 converted to TYPE and OMITTED was previously an operand of the expression
3550 but is now not needed (e.g., we folded OMITTED * 0).
3552 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3553 the conversion of RESULT to TYPE. */
3555 tree
3557 {
3560 /* If the resulting operand is an empty statement, just return the omitted
3561 statement casted to void. */
3569 }
3571 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3573 static tree
3575 {
3578 /* If the resulting operand is an empty statement, just return the omitted
3579 statement casted to void. */
3587 }
3589 /* Return a tree for the case when the result of an expression is RESULT
3590 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3591 of the expression but are now not needed.
3593 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3594 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3595 evaluated before OMITTED2. Otherwise, if neither has side effects,
3596 just do the conversion of RESULT to TYPE. */
3598 tree
3600 {
3609 }
3611 \f
3612 /* Return a simplified tree node for the truth-negation of ARG. This
3613 never alters ARG itself. We assume that ARG is an operation that
3614 returns a truth value (0 or 1).
3616 FIXME: one would think we would fold the result, but it causes
3617 problems with the dominator optimizer. */
3619 tree
3621 {
3625 /* If this is a comparison, we can simply invert it, except for
3626 floating-point non-equality comparisons, in which case we just
3627 enclose a TRUTH_NOT_EXPR around what we have. */
3630 {
3633 && flag_trapping_math
3637 else
3638 {
3643 else
3646 }
3647 }
3650 {
3665 /* Here we can invert either operand. We invert the first operand
3666 unless the second operand is a TRUTH_NOT_EXPR in which case our
3667 result is the XOR of the first operand with the inside of the
3668 negation of the second operand. */
3673 else
3692 {
3695 /* A COND_EXPR may have a throw as one operand, which
3696 then has void type. Just leave void operands
3697 as they are. */
3703 }
3736 }
3739 }
3741 /* Return a simplified tree node for the truth-negation of ARG. This
3742 never alters ARG itself. We assume that ARG is an operation that
3743 returns a truth value (0 or 1).
3745 FIXME: one would think we would fold the result, but it causes
3746 problems with the dominator optimizer. */
3748 tree
3750 {
3751 tree tem;
3761 }
3763 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3764 operands are another bit-wise operation with a common input. If so,
3765 distribute the bit operations to save an operation and possibly two if
3766 constants are involved. For example, convert
3767 (A | B) & (A | C) into A | (B & C)
3768 Further simplification will occur if B and C are constants.
3770 If this optimization cannot be done, 0 will be returned. */
3772 static tree
3774 {
3775 tree common;
3785 {
3789 }
3791 {
3795 }
3797 {
3801 }
3803 {
3807 }
3808 else
3813 }
3815 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3816 with code CODE. This optimization is unsafe. */
3817 static tree
3819 {
3823 /* (A / C) +- (B / C) -> (A +- B) / C. */
3833 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3838 {
3850 }
3853 }
3854 \f
3855 /* Subroutine for fold_truthop: decode a field reference.
3857 If EXP is a comparison reference, we return the innermost reference.
3859 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3860 set to the starting bit number.
3862 If the innermost field can be completely contained in a mode-sized
3863 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3865 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3866 otherwise it is not changed.
3868 *PUNSIGNEDP is set to the signedness of the field.
3870 *PMASK is set to the mask used. This is either contained in a
3871 BIT_AND_EXPR or derived from the width of the field.
3873 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3875 Return 0 if this is not a component reference or is one that we can't
3876 do anything with. */
3878 static tree
3883 {
3887 tree unsigned_type;
3890 /* All the optimizations using this function assume integer fields.
3891 There are problems with FP fields since the type_for_size call
3892 below can fail for, e.g., XFmode. */
3896 /* We are interested in the bare arrangement of bits, so strip everything
3897 that doesn't affect the machine mode. However, record the type of the
3898 outermost expression if it may matter below. */
3906 {
3912 }
3921 /* If the number of bits in the reference is the same as the bitsize of
3922 the outer type, then the outer type gives the signedness. Otherwise
3923 (in case of a small bitfield) the signedness is unchanged. */
3927 /* Compute the mask to access the bitfield. */
3936 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3944 }
3946 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3947 represents the sign bit of EXP's type. If EXP represents a sign
3948 or zero extension, also test VAL against the unextended type.
3949 The return value is the (sub)expression whose sign bit is VAL,
3950 or NULL_TREE otherwise. */
3952 static tree
3954 {
3958 tree t;
3960 /* Tree EXP must have an integral type. */
3965 /* Tree VAL must be an integer constant. */
3972 {
3979 }
3980 else
3981 {
3988 }
3990 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
3991 treat VAL as if it were unsigned. */
3996 /* Handle extension from a narrower type. */
4002 }
4004 /* Subroutine for fold_truthop: determine if an operand is simple enough
4005 to be evaluated unconditionally. */
4007 static int
4009 {
4010 /* Strip any conversions that don't change the machine mode. */
4019 /* Don't regard global variables as simple. They may be
4020 allocated in ways unknown to the compiler (shared memory,
4021 #pragma weak, etc). */
4024 /* Loading a static variable is unduly expensive, but global
4025 registers aren't expensive. */
4027 }
4028 \f
4029 /* The following functions are subroutines to fold_range_test and allow it to
4030 try to change a logical combination of comparisons into a range test.
4032 For example, both
4033 X == 2 || X == 3 || X == 4 || X == 5
4034 and
4035 X >= 2 && X <= 5
4036 are converted to
4037 (unsigned) (X - 2) <= 3
4039 We describe each set of comparisons as being either inside or outside
4040 a range, using a variable named like IN_P, and then describe the
4041 range with a lower and upper bound. If one of the bounds is omitted,
4042 it represents either the highest or lowest value of the type.
4044 In the comments below, we represent a range by two numbers in brackets
4045 preceded by a "+" to designate being inside that range, or a "-" to
4046 designate being outside that range, so the condition can be inverted by
4047 flipping the prefix. An omitted bound is represented by a "-". For
4048 example, "- [-, 10]" means being outside the range starting at the lowest
4049 possible value and ending at 10, in other words, being greater than 10.
4050 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4051 always false.
4053 We set up things so that the missing bounds are handled in a consistent
4054 manner so neither a missing bound nor "true" and "false" need to be
4055 handled using a special case. */
4057 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4058 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4059 and UPPER1_P are nonzero if the respective argument is an upper bound
4060 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4061 must be specified for a comparison. ARG1 will be converted to ARG0's
4062 type if both are specified. */
4064 static tree
4067 {
4068 tree tem;
4072 /* If neither arg represents infinity, do the normal operation.
4073 Else, if not a comparison, return infinity. Else handle the special
4074 comparison rules. Note that most of the cases below won't occur, but
4075 are handled for consistency. */
4078 {
4083 }
4088 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4089 for neither. In real maths, we cannot assume open ended ranges are
4090 the same. But, this is computer arithmetic, where numbers are finite.
4091 We can therefore make the transformation of any unbounded range with
4092 the value Z, Z being greater than any representable number. This permits
4093 us to treat unbounded ranges as equal. */
4097 {
4118 }
4121 }
4122 \f
4123 /* Given EXP, a logical expression, set the range it is testing into
4124 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4125 actually being tested. *PLOW and *PHIGH will be made of the same
4126 type as the returned expression. If EXP is not a comparison, we
4127 will most likely not be returning a useful value and range. Set
4128 *STRICT_OVERFLOW_P to true if the return value is only valid
4129 because signed overflow is undefined; otherwise, do not change
4130 *STRICT_OVERFLOW_P. */
4132 static tree
4135 {
4142 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4143 and see if we can refine the range. Some of the cases below may not
4144 happen, but it doesn't seem worth worrying about this. We "continue"
4145 the outer loop when we've changed something; otherwise we "break"
4146 the switch, which will "break" the while. */
4152 {
4157 {
4169 }
4172 {
4179 /* We can only do something if the range is testing for zero
4180 and if the second operand is an integer constant. Note that
4181 saying something is "in" the range we make is done by
4182 complementing IN_P since it will set in the initial case of
4183 being not equal to zero; "out" is leaving it alone. */
4190 {
4211 }
4213 /* If this is an unsigned comparison, we also know that EXP is
4214 greater than or equal to zero. We base the range tests we make
4215 on that fact, so we record it here so we can parse existing
4216 range tests. We test arg0_type since often the return type
4217 of, e.g. EQ_EXPR, is boolean. */
4219 {
4223 NULL_TREE))
4228 /* If the high bound is missing, but we have a nonzero low
4229 bound, reverse the range so it goes from zero to the low bound
4230 minus 1. */
4232 {
4237 }
4238 }
4244 /* (-x) IN [a,b] -> x in [-b, -a] */
4256 /* ~ X -> -X - 1 */
4265 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4266 move a constant to the other side. */
4271 /* If EXP is signed, any overflow in the computation is undefined,
4272 so we don't worry about it so long as our computations on
4273 the bounds don't overflow. For unsigned, overflow is defined
4274 and this is exactly the right thing. */
4286 /* Check for an unsigned range which has wrapped around the maximum
4287 value thus making n_high < n_low, and normalize it. */
4289 {
4295 /* If the range is of the form +/- [ x+1, x ], we won't
4296 be able to normalize it. But then, it represents the
4297 whole range or the empty set, so make it
4298 +/- [ -, - ]. */
4302 else
4304 }
4305 else
4329 /* If we're converting arg0 from an unsigned type, to exp,
4330 a signed type, we will be doing the comparison as unsigned.
4331 The tests above have already verified that LOW and HIGH
4332 are both positive.
4334 So we have to ensure that we will handle large unsigned
4335 values the same way that the current signed bounds treat
4336 negative values. */
4339 {
4340 tree high_positive;
4341 tree equiv_type;
4342 /* For fixed-point modes, we need to pass the saturating flag
4343 as the 2nd parameter. */
4348 else
4352 /* A range without an upper bound is, naturally, unbounded.
4353 Since convert would have cropped a very large value, use
4354 the max value for the destination type. */
4355 high_positive
4362 high_positive),
4365 /* If the low bound is specified, "and" the range with the
4366 range for which the original unsigned value will be
4367 positive. */
4369 {
4373 integer_zero_node),
4374 high_positive))
4378 }
4379 else
4380 {
4381 /* Otherwise, "or" the range with the range of the input
4382 that will be interpreted as negative. */
4386 integer_zero_node),
4387 high_positive))
4391 }
4392 }
4400 }
4403 }
4405 /* If EXP is a constant, we can evaluate whether this is true or false. */
4407 {
4414 }
4418 }
4419 \f
4420 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4421 type, TYPE, return an expression to test if EXP is in (or out of, depending
4422 on IN_P) the range. Return 0 if the test couldn't be created. */
4424 static tree
4426 {
4428 tree value;
4430 #ifdef HAVE_canonicalize_funcptr_for_compare
4431 /* Disable this optimization for function pointer expressions
4432 on targets that require function pointer canonicalization. */
4437 #endif
4440 {
4446 }
4464 {
4466 {
4470 }
4472 }
4474 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4476 {
4478 HOST_WIDE_INT hi;
4483 {
4486 }
4487 else
4488 {
4491 }
4494 {
4496 {
4499 }
4502 }
4503 }
4505 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4506 This requires wrap-around arithmetics for the type of the expression. */
4508 {
4510 /* There is no requirement that LOW be within the range of ETYPE
4511 if the latter is a subtype. It must, however, be within the base
4512 type of ETYPE. So be sure we do the subtraction in that type. */
4525 }
4527 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4530 {
4533 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4534 for the type in question, as we rely on this here. */
4544 else
4546 }
4556 {
4558 {
4564 }
4566 }
4574 }
4575 \f
4576 /* Return the predecessor of VAL in its type, handling the infinite case. */
4578 static tree
4580 {
4586 else
4588 }
4590 /* Return the successor of VAL in its type, handling the infinite case. */
4592 static tree
4594 {
4600 else
4602 }
4604 /* Given two ranges, see if we can merge them into one. Return 1 if we
4605 can, 0 if we can't. Set the output range into the specified parameters. */
4607 static int
4610 {
4614 tree tem;
4624 /* Make range 0 be the range that starts first, or ends last if they
4625 start at the same value. Swap them if it isn't. */
4628 || (lowequal
4631 {
4635 }
4637 /* Now flag two cases, whether the ranges are disjoint or whether the
4638 second range is totally subsumed in the first. Note that the tests
4639 below are simplified by the ones above. */
4645 /* We now have four cases, depending on whether we are including or
4646 excluding the two ranges. */
4648 {
4649 /* If they don't overlap, the result is false. If the second range
4650 is a subset it is the result. Otherwise, the range is from the start
4651 of the second to the end of the first. */
4656 else
4658 }
4661 {
4662 /* If they don't overlap, the result is the first range. If they are
4663 equal, the result is false. If the second range is a subset of the
4664 first, and the ranges begin at the same place, we go from just after
4665 the end of the second range to the end of the first. If the second
4666 range is not a subset of the first, or if it is a subset and both
4667 ranges end at the same place, the range starts at the start of the
4668 first range and ends just before the second range.
4669 Otherwise, we can't describe this as a single range. */
4675 {
4680 {
4681 /* We are in the weird situation where high0 > high1 but
4682 high1 has no successor. Punt. */
4684 }
4685 }
4687 {
4692 {
4693 /* low0 < low1 but low1 has no predecessor. Punt. */
4695 }
4696 }
4697 else
4699 }
4702 {
4703 /* If they don't overlap, the result is the second range. If the second
4704 is a subset of the first, the result is false. Otherwise,
4705 the range starts just after the first range and ends at the
4706 end of the second. */
4711 else
4712 {
4717 {
4718 /* high1 > high0 but high0 has no successor. Punt. */
4720 }
4721 }
4722 }
4724 else
4725 {
4726 /* The case where we are excluding both ranges. Here the complex case
4727 is if they don't overlap. In that case, the only time we have a
4728 range is if they are adjacent. If the second is a subset of the
4729 first, the result is the first. Otherwise, the range to exclude
4730 starts at the beginning of the first range and ends at the end of the
4731 second. */
4733 {
4738 else
4739 {
4740 /* Canonicalize - [min, x] into - [-, x]. */
4743 {
4748 /* FALLTHROUGH */
4761 }
4763 /* Canonicalize - [x, max] into - [x, -]. */
4766 {
4771 /* FALLTHROUGH */
4786 }
4788 /* The ranges might be also adjacent between the maximum and
4789 minimum values of the given type. For
4790 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4791 return + [x + 1, y - 1]. */
4793 {
4800 }
4801 else
4803 }
4804 }
4807 else
4809 }
4813 }
4814 \f
4816 /* Subroutine of fold, looking inside expressions of the form
4817 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4818 of the COND_EXPR. This function is being used also to optimize
4819 A op B ? C : A, by reversing the comparison first.
4821 Return a folded expression whose code is not a COND_EXPR
4822 anymore, or NULL_TREE if no folding opportunity is found. */
4824 static tree
4826 {
4831 tree tem;
4836 /* If we have A op 0 ? A : -A, consider applying the following
4837 transformations:
4839 A == 0? A : -A same as -A
4840 A != 0? A : -A same as A
4841 A >= 0? A : -A same as abs (A)
4842 A > 0? A : -A same as abs (A)
4843 A <= 0? A : -A same as -abs (A)
4844 A < 0? A : -A same as -abs (A)
4846 None of these transformations work for modes with signed
4847 zeros. If A is +/-0, the first two transformations will
4848 change the sign of the result (from +0 to -0, or vice
4849 versa). The last four will fix the sign of the result,
4850 even though the original expressions could be positive or
4851 negative, depending on the sign of A.
4853 Note that all these transformations are correct if A is
4854 NaN, since the two alternatives (A and -A) are also NaNs. */
4861 /* In the case that A is of the form X-Y, '-A' (arg2) may
4862 have already been folded to Y-X, check for that. */
4870 {
4882 /* Fall through. */
4904 }
4906 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4907 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4908 both transformations are correct when A is NaN: A != 0
4909 is then true, and A == 0 is false. */
4913 {
4918 }
4920 /* Try some transformations of A op B ? A : B.
4922 A == B? A : B same as B
4923 A != B? A : B same as A
4924 A >= B? A : B same as max (A, B)
4925 A > B? A : B same as max (B, A)
4926 A <= B? A : B same as min (A, B)
4927 A < B? A : B same as min (B, A)
4929 As above, these transformations don't work in the presence
4930 of signed zeros. For example, if A and B are zeros of
4931 opposite sign, the first two transformations will change
4932 the sign of the result. In the last four, the original
4933 expressions give different results for (A=+0, B=-0) and
4934 (A=-0, B=+0), but the transformed expressions do not.
4936 The first two transformations are correct if either A or B
4937 is a NaN. In the first transformation, the condition will
4938 be false, and B will indeed be chosen. In the case of the
4939 second transformation, the condition A != B will be true,
4940 and A will be chosen.
4942 The conversions to max() and min() are not correct if B is
4943 a number and A is not. The conditions in the original
4944 expressions will be false, so all four give B. The min()
4945 and max() versions would give a NaN instead. */
4948 /* Avoid these transformations if the COND_EXPR may be used
4949 as an lvalue in the C++ front-end. PR c++/19199. */
4950 && (in_gimple_form
4955 {
4960 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4962 {
4966 }
4969 {
4978 /* In C++ a ?: expression can be an lvalue, so put the
4979 operand which will be used if they are equal first
4980 so that we can convert this back to the
4981 corresponding COND_EXPR. */
4983 {
4990 }
4997 {
5004 }
5017 }
5018 }
5020 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5021 we might still be able to simplify this. For example,
5022 if C1 is one less or one more than C2, this might have started
5023 out as a MIN or MAX and been transformed by this function.
5024 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5030 {
5032 /* We can replace A with C1 in this case. */
5037 /* If C1 is C2 + 1, this is min(A, C2). */
5039 OEP_ONLY_CONST)
5043 OEP_ONLY_CONST))
5045 type,
5047 arg2));
5051 /* If C1 is C2 - 1, this is min(A, C2). */
5053 OEP_ONLY_CONST)
5057 OEP_ONLY_CONST))
5059 type,
5061 arg2));
5065 /* If C1 is C2 - 1, this is max(A, C2). */
5067 OEP_ONLY_CONST)
5071 OEP_ONLY_CONST))
5073 type,
5075 arg2));
5079 /* If C1 is C2 + 1, this is max(A, C2). */
5081 OEP_ONLY_CONST)
5085 OEP_ONLY_CONST))
5087 type,
5089 arg2));
5095 }
5098 }
5101 \f
5102 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5103 #define LOGICAL_OP_NON_SHORT_CIRCUIT (BRANCH_COST >= 2)
5104 #endif
5106 /* EXP is some logical combination of boolean tests. See if we can
5107 merge it into some range test. Return the new tree if so. */
5109 static tree
5111 {
5119 tree tem;
5123 /* If this is an OR operation, invert both sides; we will invert
5124 again at the end. */
5128 /* If both expressions are the same, if we can merge the ranges, and we
5129 can build the range test, return it or it inverted. If one of the
5130 ranges is always true or always false, consider it to be the same
5131 expression as the other. */
5139 {
5143 }
5145 /* On machines where the branch cost is expensive, if this is a
5146 short-circuited branch and the underlying object on both sides
5147 is the same, make a non-short-circuit operation. */
5153 {
5154 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5155 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5156 which cases we can't do this. */
5164 {
5173 {
5176 WARN_STRICT_OVERFLOW_COMPARISON);
5180 }
5181 }
5182 }
5185 }
5186 \f
5187 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5188 bit value. Arrange things so the extra bits will be set to zero if and
5189 only if C is signed-extended to its full width. If MASK is nonzero,
5190 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5192 static tree
5194 {
5197 tree temp;
5202 /* We work by getting just the sign bit into the low-order bit, then
5203 into the high-order bit, then sign-extend. We then XOR that value
5204 with C. */
5208 /* We must use a signed type in order to get an arithmetic right shift.
5209 However, we must also avoid introducing accidental overflows, so that
5210 a subsequent call to integer_zerop will work. Hence we must
5211 do the type conversion here. At this point, the constant is either
5212 zero or one, and the conversion to a signed type can never overflow.
5213 We could get an overflow if this conversion is done anywhere else. */
5222 /* If necessary, convert the type back to match the type of C. */
5227 }
5228 \f
5229 /* Find ways of folding logical expressions of LHS and RHS:
5230 Try to merge two comparisons to the same innermost item.
5231 Look for range tests like "ch >= '0' && ch <= '9'".
5232 Look for combinations of simple terms on machines with expensive branches
5233 and evaluate the RHS unconditionally.
5235 For example, if we have p->a == 2 && p->b == 4 and we can make an
5236 object large enough to span both A and B, we can do this with a comparison
5237 against the object ANDed with the a mask.
5239 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5240 operations to do this with one comparison.
5242 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5243 function and the one above.
5245 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5246 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5248 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5249 two operands.
5251 We return the simplified tree or 0 if no optimization is possible. */
5253 static tree
5255 {
5256 /* If this is the "or" of two comparisons, we can do something if
5257 the comparisons are NE_EXPR. If this is the "and", we can do something
5258 if the comparisons are EQ_EXPR. I.e.,
5259 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5261 WANTED_CODE is this operation code. For single bit fields, we can
5262 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5263 comparison for one-bit fields. */
5285 /* Start by getting the comparison codes. Fail if anything is volatile.
5286 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5287 it were surrounded with a NE_EXPR. */
5296 {
5300 }
5303 {
5307 }
5318 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5321 {
5322 tree result;
5325 {
5330 }
5333 {
5339 }
5340 }
5345 /* If the RHS can be evaluated unconditionally and its operands are
5346 simple, it wins to evaluate the RHS unconditionally on machines
5347 with expensive branches. In this case, this isn't a comparison
5348 that can be merged. Avoid doing this if the RHS is a floating-point
5349 comparison since those can trap. */
5355 {
5356 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5366 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5377 {
5381 }
5382 }
5384 /* See if the comparisons can be merged. Then get all the parameters for
5385 each side. */
5409 /* It must be true that the inner operation on the lhs of each
5410 comparison must be the same if we are to be able to do anything.
5411 Then see if we have constants. If not, the same must be true for
5412 the rhs's. */
5423 else
5426 /* If either comparison code is not correct for our logical operation,
5427 fail. However, we can convert a one-bit comparison against zero into
5428 the opposite comparison against that bit being set in the field. */
5432 {
5434 {
5435 /* Make the left operand unsigned, since we are only interested
5436 in the value of one bit. Otherwise we are doing the wrong
5437 thing below. */
5440 }
5441 else
5443 }
5445 /* This is analogous to the code for l_const above. */
5447 {
5449 {
5452 }
5453 else
5455 }
5457 /* See if we can find a mode that contains both fields being compared on
5458 the left. If we can't, fail. Otherwise, update all constants and masks
5459 to be relative to a field of that size. */
5464 volatilep);
5474 {
5477 }
5485 {
5493 {
5497 }
5498 }
5500 {
5508 {
5512 }
5513 }
5515 /* Handle the case of comparisons with constants. If there is something in
5516 common between the masks, those bits of the constants must be the same.
5517 If not, the condition is always false. Test for this to avoid generating
5518 incorrect code below. */
5523 {
5525 {
5528 }
5529 else
5530 {
5533 }
5534 }
5537 }
5538 \f
5539 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5540 constant. */
5542 static tree
5544 {
5548 tree minmax_const;
5550 tree inner;
5560 /* If something does not permit us to optimize, return the original tree. */
5568 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5569 and GT_EXPR, doing the rest with recursive calls using logical
5570 simplifications. */
5572 {
5574 {
5580 }
5583 return
5585 optimize_minmax_comparison
5587 optimize_minmax_comparison
5592 /* MAX (X, 0) == 0 -> X <= 0 */
5596 /* MAX (X, 0) == 5 -> X == 5 */
5600 /* MAX (X, 0) == -1 -> false */
5604 /* MIN (X, 0) == 0 -> X >= 0 */
5608 /* MIN (X, 0) == 5 -> false */
5611 else
5612 /* MIN (X, 0) == -1 -> X == -1 */
5617 /* MAX (X, 0) > 0 -> X > 0
5618 MAX (X, 0) > 5 -> X > 5 */
5622 /* MAX (X, 0) > -1 -> true */
5626 /* MIN (X, 0) > 0 -> false
5627 MIN (X, 0) > 5 -> false */
5630 else
5631 /* MIN (X, 0) > -1 -> X > -1 */
5636 }
5637 }
5638 \f
5639 /* T is an integer expression that is being multiplied, divided, or taken a
5640 modulus (CODE says which and what kind of divide or modulus) by a
5641 constant C. See if we can eliminate that operation by folding it with
5642 other operations already in T. WIDE_TYPE, if non-null, is a type that
5643 should be used for the computation if wider than our type.
5645 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5646 (X * 2) + (Y * 4). We must, however, be assured that either the original
5647 expression would not overflow or that overflow is undefined for the type
5648 in the language in question.
5650 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5651 the machine has a multiply-accumulate insn or that this is part of an
5652 addressing calculation.
5654 If we return a non-null expression, it is an equivalent form of the
5655 original computation, but need not be in the original type.
5657 We set *STRICT_OVERFLOW_P to true if the return values depends on
5658 signed overflow being undefined. Otherwise we do not change
5659 *STRICT_OVERFLOW_P. */
5661 static tree
5664 {
5665 /* To avoid exponential search depth, refuse to allow recursion past
5666 three levels. Beyond that (1) it's highly unlikely that we'll find
5667 something interesting and (2) we've probably processed it before
5668 when we built the inner expression. */
5671 tree ret;
5676 depth++;
5678 depth--;
5681 }
5683 static tree
5686 {
5697 /* Don't deal with constants of zero here; they confuse the code below. */
5707 /* Note that we need not handle conditional operations here since fold
5708 already handles those cases. So just do arithmetic here. */
5710 {
5712 /* For a constant, we can always simplify if we are a multiply
5713 or (for divide and modulus) if it is a multiple of our constant. */
5721 /* If op0 is an expression ... */
5727 /* ... and is unsigned, and its type is smaller than ctype,
5728 then we cannot pass through as widening. */
5734 /* ... or this is a truncation (t is narrower than op0),
5735 then we cannot pass through this narrowing. */
5738 /* ... or signedness changes for division or modulus,
5739 then we cannot pass through this conversion. */
5743 /* ... or has undefined overflow while the converted to
5744 type has not, we cannot do the operation in the inner type
5745 as that would introduce undefined overflow. */
5750 /* Pass the constant down and see if we can make a simplification. If
5751 we can, replace this expression with the inner simplification for
5752 possible later conversion to our or some other type. */
5757 code == MULT_EXPR
5759 strict_overflow_p))))
5764 /* If widening the type changes it from signed to unsigned, then we
5765 must avoid building ABS_EXPR itself as unsigned. */
5767 {
5771 {
5774 }
5776 }
5777 /* If the constant is negative, we cannot simplify this. */
5780 /* FALLTHROUGH */
5788 /* If widening the type changes the signedness, then we can't perform
5789 this optimization as that changes the result. */
5793 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5799 {
5806 }
5810 /* If the second operand is constant, this is a multiplication
5811 or floor division, by a power of two, so we can treat it that
5812 way unless the multiplier or divisor overflows. Signed
5813 left-shift overflow is implementation-defined rather than
5814 undefined in C90, so do not convert signed left shift into
5815 multiplication. */
5818 /* const_binop may not detect overflow correctly,
5819 so check for it explicitly here. */
5824 size_one_node,
5834 /* See if we can eliminate the operation on both sides. If we can, we
5835 can return a new PLUS or MINUS. If we can't, the only remaining
5836 cases where we can do anything are if the second operand is a
5837 constant. */
5843 /* If not multiplication, we can only do this if both operands
5844 are divisible by c. */
5847 {
5852 }
5854 /* If this was a subtraction, negate OP1 and set it to be an addition.
5855 This simplifies the logic below. */
5862 /* If either OP1 or C are negative, this optimization is not safe for
5863 some of the division and remainder types while for others we need
5864 to change the code. */
5866 {
5874 }
5876 /* If it's a multiply or a division/modulus operation of a multiple
5877 of our constant, do the operation and verify it doesn't overflow. */
5880 {
5883 /* We allow the constant to overflow with wrapping semantics. */
5887 }
5888 else
5891 /* If we have an unsigned type is not a sizetype, we cannot widen
5892 the operation since it will change the result if the original
5893 computation overflowed. */
5899 /* If we were able to eliminate our operation from the first side,
5900 apply our operation to the second side and reform the PLUS. */
5904 /* The last case is if we are a multiply. In that case, we can
5905 apply the distributive law to commute the multiply and addition
5906 if the multiplication of the constants doesn't overflow. */
5912 op1);
5917 /* We have a special case here if we are doing something like
5918 (C * 8) % 4 since we know that's zero. */
5925 /* ... fall through ... */
5929 /* If we can extract our operation from the LHS, do so and return a
5930 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5931 do something only if the second operand is a constant. */
5945 /* If these are the same operation types, we can associate them
5946 assuming no overflow. */
5953 /* If these operations "cancel" each other, we have the main
5954 optimizations of this pass, which occur when either constant is a
5955 multiple of the other, in which case we replace this with either an
5956 operation or CODE or TCODE.
5958 If we have an unsigned type that is not a sizetype, we cannot do
5959 this since it will change the result if the original computation
5960 overflowed. */
5968 {
5970 {
5977 }
5979 {
5986 }
5987 }
5992 }
5995 }
5996 \f
5997 /* Return a node which has the indicated constant VALUE (either 0 or
5998 1), and is of the indicated TYPE. */
6000 tree
6002 {
6007 else
6009 }
6012 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6013 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6014 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6015 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6016 COND is the first argument to CODE; otherwise (as in the example
6017 given here), it is the second argument. TYPE is the type of the
6018 original expression. Return NULL_TREE if no simplification is
6019 possible. */
6021 static tree
6025 {
6032 /* This transformation is only worthwhile if we don't have to wrap
6033 arg in a SAVE_EXPR, and the operation can be simplified on at least
6034 one of the branches once its pushed inside the COND_EXPR. */
6039 {
6043 /* If this operand throws an expression, then it does not make
6044 sense to try to perform a logical or arithmetic operation
6045 involving it. */
6050 }
6051 else
6052 {
6057 }
6061 {
6065 else
6067 }
6069 {
6073 else
6075 }
6079 }
6081 \f
6082 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6084 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6085 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6086 ADDEND is the same as X.
6088 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6089 and finite. The problematic cases are when X is zero, and its mode
6090 has signed zeros. In the case of rounding towards -infinity,
6091 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6092 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6094 bool
6096 {
6100 /* Don't allow the fold with -fsignaling-nans. */
6104 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6108 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6113 /* The mode has signed zeros, and we have to honor their sign.
6114 In this situation, there is only one case we can return true for.
6115 X - 0 is the same as X unless rounding towards -infinity is
6116 supported. */
6118 }
6120 /* Subroutine of fold() that checks comparisons of built-in math
6121 functions against real constants.
6123 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6124 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6125 is the type of the result and ARG0 and ARG1 are the operands of the
6126 comparison. ARG1 must be a TREE_REAL_CST.
6128 The function returns the constant folded tree if a simplification
6129 can be made, and NULL_TREE otherwise. */
6131 static tree
6134 {
6135 REAL_VALUE_TYPE c;
6138 {
6144 {
6145 /* sqrt(x) < y is always false, if y is negative. */
6149 /* sqrt(x) > y is always true, if y is negative and we
6150 don't care about NaNs, i.e. negative values of x. */
6154 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6157 }
6159 {
6160 REAL_VALUE_TYPE c2;
6166 {
6167 /* sqrt(x) > y is x == +Inf, when y is very large. */
6172 /* sqrt(x) > y is always false, when y is very large
6173 and we don't care about infinities. */
6175 }
6177 /* sqrt(x) > c is the same as x > c*c. */
6180 }
6182 {
6183 REAL_VALUE_TYPE c2;
6189 {
6190 /* sqrt(x) < y is always true, when y is a very large
6191 value and we don't care about NaNs or Infinities. */
6195 /* sqrt(x) < y is x != +Inf when y is very large and we
6196 don't care about NaNs. */
6201 /* sqrt(x) < y is x >= 0 when y is very large and we
6202 don't care about Infinities. */
6207 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6216 dconst0)),
6219 c2)));
6220 }
6222 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6227 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6230 {
6235 dconst0)),
6238 c2)));
6239 }
6240 }
6241 }
6244 }
6246 /* Subroutine of fold() that optimizes comparisons against Infinities,
6247 either +Inf or -Inf.
6249 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6250 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6251 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6253 The function returns the constant folded tree if a simplification
6254 can be made, and NULL_TREE otherwise. */
6256 static tree
6258 {
6260 REAL_VALUE_TYPE max;
6261 tree temp;
6266 /* For negative infinity swap the sense of the comparison. */
6272 {
6274 /* x > +Inf is always false, if with ignore sNANs. */
6280 /* x <= +Inf is always true, if we don't case about NaNs. */
6284 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6287 {
6290 }
6295 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6301 /* x < +Inf is always equal to x <= DBL_MAX. */
6307 /* x != +Inf is always equal to !(x > DBL_MAX). */
6319 }
6322 }
6324 /* Subroutine of fold() that optimizes comparisons of a division by
6325 a nonzero integer constant against an integer constant, i.e.
6326 X/C1 op C2.
6328 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6329 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6330 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6332 The function returns the constant folded tree if a simplification
6333 can be made, and NULL_TREE otherwise. */
6335 static tree
6337 {
6342 HOST_WIDE_INT hpart;
6347 /* We have to do this the hard way to detect unsigned overflow.
6348 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6359 {
6364 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6372 }
6374 {
6378 {
6397 }
6398 }
6399 else
6400 {
6401 /* A negative divisor reverses the relational operators. */
6407 {
6426 }
6427 }
6430 {
6451 {
6454 }
6459 {
6462 }
6467 {
6470 }
6475 {
6478 }
6483 }
6486 }
6489 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6490 equality/inequality test, then return a simplified form of the test
6491 using a sign testing. Otherwise return NULL. TYPE is the desired
6492 result type. */
6494 static tree
6496 tree result_type)
6497 {
6498 /* If this is testing a single bit, we can optimize the test. */
6502 {
6503 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6504 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6508 /* This is only a win if casting to a signed type is cheap,
6509 i.e. when arg00's type is not a partial mode. */
6512 {
6517 }
6518 }
6521 }
6523 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6524 equality/inequality test, then return a simplified form of
6525 the test using shifts and logical operations. Otherwise return
6526 NULL. TYPE is the desired result type. */
6528 tree
6530 tree result_type)
6531 {
6532 /* If this is testing a single bit, we can optimize the test. */
6536 {
6545 /* First, see if we can fold the single bit test into a sign-bit
6546 test. */
6548 result_type);
6552 /* Otherwise we have (A & C) != 0 where C is a single bit,
6553 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6554 Similarly for (A & C) == 0. */
6556 /* If INNER is a right shift of a constant and it plus BITNUM does
6557 not overflow, adjust BITNUM and INNER. */
6564 {
6567 }
6569 /* If we are going to be able to omit the AND below, we must do our
6570 operations as unsigned. If we must use the AND, we have a choice.
6571 Normally unsigned is faster, but for some machines signed is. */
6572 #ifdef LOAD_EXTEND_OP
6575 #else
6577 #endif
6593 /* Put the AND last so it can combine with more things. */
6596 /* Make sure to return the proper type. */
6600 }
6602 }
6604 /* Check whether we are allowed to reorder operands arg0 and arg1,
6605 such that the evaluation of arg1 occurs before arg0. */
6607 static bool
6609 {
6616 }
6618 /* Test whether it is preferable two swap two operands, ARG0 and
6619 ARG1, for example because ARG0 is an integer constant and ARG1
6620 isn't. If REORDER is true, only recommend swapping if we can
6621 evaluate the operands in reverse order. */
6623 bool
6625 {
6661 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6662 for commutative and comparison operators. Ensuring a canonical
6663 form allows the optimizers to find additional redundancies without
6664 having to explicitly check for both orderings. */
6670 /* Put SSA_NAMEs last. */
6676 /* Put variables last. */
6683 }
6685 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6686 ARG0 is extended to a wider type. */
6688 static tree
6690 {
6692 tree arg1_unw;
6701 #ifdef HAVE_canonicalize_funcptr_for_compare
6702 /* Disable this optimization if we're casting a function pointer
6703 type on targets that require function pointer canonicalization. */
6708 #endif
6715 /* If possible, express the comparison in the shorter mode. */
6733 /* If we are comparing with the integer that does not fit into the range
6734 of the shorter type, the result is known. */
6745 {
6772 }
6775 }
6777 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6778 ARG0 just the signedness is changed. */
6780 static tree
6783 {
6784 tree arg0_inner;
6795 #ifdef HAVE_canonicalize_funcptr_for_compare
6796 /* Disable this optimization if we're casting a function pointer
6797 type on targets that require function pointer canonicalization. */
6802 #endif
6822 else
6826 }
6828 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6829 step of the array. Reconstructs s and delta in the case of s * delta
6830 being an integer constant (and thus already folded).
6831 ADDR is the address. MULT is the multiplicative expression.
6832 If the function succeeds, the new address expression is returned. Otherwise
6833 NULL_TREE is returned. */
6835 static tree
6837 {
6841 tree itype;
6844 /* Strip the nops that might be added when converting op1 to sizetype. */
6847 /* Canonicalize op1 into a possibly non-constant delta
6848 and an INTEGER_CST s. */
6850 {
6857 {
6860 }
6862 {
6865 }
6866 else
6868 }
6870 {
6873 }
6874 else
6875 {
6876 /* Simulate we are delta * 1. */
6879 }
6882 {
6884 {
6885 /* Remember if this was a multi-dimensional array. */
6898 {
6901 }
6902 else
6903 {
6904 /* Try if delta is a multiple of step. */
6909 }
6911 /* Only fold here if we can verify we do not overflow one
6912 dimension of a multi-dimensional array. */
6914 {
6915 tree tmp;
6931 }
6934 }
6935 else
6940 }
6942 /* We found the suitable array reference. So copy everything up to it,
6943 and replace the index. */
6950 {
6954 }
6962 }
6965 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6966 means A >= Y && A != MAX, but in this case we know that
6967 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6969 static tree
6971 {
6978 else
6987 {
6990 }
6992 {
6995 }
6996 else
7003 {
7004 /* Convert the pointer types into integer before taking the difference. */
7008 }
7009 else
7016 }
7018 /* Fold a sum or difference of at least one multiplication.
7019 Returns the folded tree or NULL if no simplification could be made. */
7021 static tree
7023 {
7027 /* (A * C) +- (B * C) -> (A+-B) * C.
7028 (A * C) +- A -> A * (C+-1).
7029 We are most concerned about the case where C is a constant,
7030 but other combinations show up during loop reduction. Since
7031 it is not difficult, try all four possibilities. */
7034 {
7037 }
7039 {
7042 }
7043 else
7044 {
7045 /* We cannot generate constant 1 for fract. */
7050 }
7052 {
7055 }
7057 {
7060 }
7061 else
7062 {
7063 /* We cannot generate constant 1 for fract. */
7068 }
7080 /* No identical multiplicands; see if we can find a common
7081 power-of-two factor in non-power-of-two multiplies. This
7082 can help in multi-dimensional array access. */
7085 {
7088 tree maybe_same;
7092 /* Move min of absolute values to int11. */
7095 {
7100 }
7101 else
7105 {
7113 }
7114 }
7124 }
7126 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7127 specified by EXPR into the buffer PTR of length LEN bytes.
7128 Return the number of bytes placed in the buffer, or zero
7129 upon failure. */
7131 static int
7133 {
7144 {
7148 else
7153 {
7160 else
7162 }
7163 else
7166 }
7168 }
7171 /* Subroutine of native_encode_expr. Encode the REAL_CST
7172 specified by EXPR into the buffer PTR of length LEN bytes.
7173 Return the number of bytes placed in the buffer, or zero
7174 upon failure. */
7176 static int
7178 {
7184 /* There are always 32 bits in each long, no matter the size of
7185 the hosts long. We handle floating point representations with
7186 up to 192 bits. */
7197 {
7202 {
7209 else
7211 }
7212 else
7215 }
7217 }
7219 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7220 specified by EXPR into the buffer PTR of length LEN bytes.
7221 Return the number of bytes placed in the buffer, or zero
7222 upon failure. */
7224 static int
7226 {
7228 tree part;
7239 }
7242 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7243 specified by EXPR into the buffer PTR of length LEN bytes.
7244 Return the number of bytes placed in the buffer, or zero
7245 upon failure. */
7247 static int
7249 {
7259 {
7261 {
7264 }
7265 else
7269 {
7272 }
7273 else
7274 {
7278 }
7280 }
7282 }
7285 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7286 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7287 buffer PTR of length LEN bytes. Return the number of bytes
7288 placed in the buffer, or zero upon failure. */
7290 int
7292 {
7294 {
7309 }
7310 }
7313 /* Subroutine of native_interpret_expr. Interpret the contents of
7314 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7315 If the buffer cannot be interpreted, return NULL_TREE. */
7317 static tree
7319 {
7333 {
7336 {
7343 else
7345 }
7346 else
7352 else
7355 }
7358 }
7361 /* Subroutine of native_interpret_expr. Interpret the contents of
7362 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7363 If the buffer cannot be interpreted, return NULL_TREE. */
7365 static tree
7367 {
7372 /* There are always 32 bits in each long, no matter the size of
7373 the hosts long. We handle floating point representations with
7374 up to 192 bits. */
7375 REAL_VALUE_TYPE r;
7386 {
7389 {
7396 else
7398 }
7399 else
7404 }
7408 }
7411 /* Subroutine of native_interpret_expr. Interpret the contents of
7412 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7413 If the buffer cannot be interpreted, return NULL_TREE. */
7415 static tree
7417 {
7432 }
7435 /* Subroutine of native_interpret_expr. Interpret the contents of
7436 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7437 If the buffer cannot be interpreted, return NULL_TREE. */
7439 static tree
7441 {
7453 {
7458 }
7460 }
7463 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7464 the buffer PTR of length LEN as a constant of type TYPE. For
7465 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7466 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7467 return NULL_TREE. */
7469 tree
7471 {
7473 {
7490 }
7491 }
7494 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7495 TYPE at compile-time. If we're unable to perform the conversion
7496 return NULL_TREE. */
7498 static tree
7500 {
7501 /* We support up to 512-bit values (for V8DFmode). */
7505 /* Check that the host and target are sane. */
7514 }
7516 /* Build an expression for the address of T. Folds away INDIRECT_REF
7517 to avoid confusing the gimplify process. When IN_FOLD is true
7518 avoid modifications of T. */
7520 static tree
7522 {
7523 /* The size of the object is not relevant when talking about its address. */
7527 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7530 {
7535 }
7537 {
7547 }
7548 else
7552 }
7554 /* Build an expression for the address of T with type PTRTYPE. This
7555 function modifies the input parameter 'T' by sometimes setting the
7556 TREE_ADDRESSABLE flag. */
7558 tree
7560 {
7562 }
7564 /* Build an expression for the address of T. This function modifies
7565 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7566 flag. When called from fold functions, use fold_addr_expr instead. */
7568 tree
7570 {
7574 }
7576 /* Same as build_fold_addr_expr, builds an expression for the address
7577 of T, but avoids touching the input node 't'. Fold functions
7578 should use this version. */
7580 static tree
7582 {
7586 }
7588 /* Fold a unary expression of code CODE and type TYPE with operand
7589 OP0. Return the folded expression if folding is successful.
7590 Otherwise, return NULL_TREE. */
7592 tree
7594 {
7595 tree tem;
7596 tree arg0;
7604 {
7607 {
7608 /* Don't use STRIP_NOPS, because signedness of argument type
7609 matters. */
7611 }
7612 else
7613 {
7614 /* Strip any conversions that don't change the mode. This
7615 is safe for every expression, except for a comparison
7616 expression because its signedness is derived from its
7617 operands.
7619 Note that this is done as an internal manipulation within
7620 the constant folder, in order to find the simplest
7621 representation of the arguments so that their form can be
7622 studied. In any cases, the appropriate type conversions
7623 should be put back in the tree that will get out of the
7624 constant folder. */
7626 }
7627 }
7630 {
7635 {
7645 /* If this was a conversion, and all we did was to move into
7646 inside the COND_EXPR, bring it back out. But leave it if
7647 it is a conversion from integer to integer and the
7648 result precision is no wider than a word since such a
7649 conversion is cheap and may be optimized away by combine,
7650 while it couldn't if it were outside the COND_EXPR. Then return
7651 so we don't get into an infinite recursion loop taking the
7652 conversion out and then back in. */
7664 && (INTEGRAL_TYPE_P
7676 }
7678 {
7680 {
7684 }
7688 integer_one_node),
7690 integer_zero_node));
7691 }
7692 }
7695 {
7697 /* Re-association barriers around constants and other re-association
7698 barriers can be removed. */
7711 /* If we have (type) (a CMP b) and type is an integral type, return
7712 new expression involving the new type. */
7717 /* Handle cases of two conversions in a row. */
7720 {
7742 /* In addition to the cases of two conversions in a row
7743 handled below, if we are converting something to its own
7744 type via an object of identical or wider precision, neither
7745 conversion is needed. */
7752 /* Likewise, if the intermediate and final types are either both
7753 float or both integer, we don't need the middle conversion if
7754 it is wider than the final type and doesn't change the signedness
7755 (for integers). Avoid this if the final type is a pointer
7756 since then we sometimes need the inner conversion. Likewise if
7757 the outer has a precision not equal to the size of its mode. */
7766 && ! final_ptr
7770 /* If we have a sign-extension of a zero-extended value, we can
7771 replace that by a single zero-extension. */
7777 /* Two conversions in a row are not needed unless:
7778 - some conversion is floating-point (overstrict for now), or
7779 - some conversion is a vector (overstrict for now), or
7780 - the intermediate type is narrower than both initial and
7781 final, or
7782 - the intermediate type and innermost type differ in signedness,
7783 and the outermost type is wider than the intermediate, or
7784 - the initial type is a pointer type and the precisions of the
7785 intermediate and final types differ, or
7786 - the final type is a pointer type and the precisions of the
7787 initial and intermediate types differ.
7788 - the initial type is a pointer to an array and the final type
7789 not. */
7806 }
7808 /* Handle (T *)&A.B.C for A being of type T and B and C
7809 living at offset zero. This occurs frequently in
7810 C++ upcasting and then accessing the base. */
7814 {
7816 tree offset;
7822 /* If the reference was to a (constant) zero offset, we can use
7823 the address of the base if it has the same base type
7824 as the result type. */
7829 }
7834 /* Detect assigning a bitfield. */
7836 && DECL_BIT_FIELD
7838 {
7839 /* Don't leave an assignment inside a conversion
7840 unless assigning a bitfield. */
7842 /* First do the assignment, then return converted constant. */
7847 }
7849 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7850 constants (if x has signed type, the sign bit cannot be set
7851 in c). This folds extension into the BIT_AND_EXPR. */
7856 {
7866 <= HOST_BITS_PER_WIDE_INT
7868 {
7875 #ifdef LOAD_EXTEND_OP
7877 && !flag_syntax_only
7880 {
7884 }
7885 #endif
7886 }
7888 {
7894 }
7895 }
7897 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7898 when one of the new casts will fold away. Conservatively we assume
7899 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7905 {
7911 }
7913 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7914 of the same precision, and X is an integer type not narrower than
7915 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7922 {
7927 }
7929 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7930 type of X and Y (integer types only). */
7935 {
7936 /* Be careful not to introduce new overflows. */
7937 tree mult_type;
7940 else
7947 }
7962 /* For integral conversions with the same precision or pointer
7963 conversions use a NOP_EXPR instead. */
7966 /* Do not muck with VIEW_CONVERT_EXPRs that convert from
7967 a sub-type to its base type as generated by the Ada FE. */
7972 /* Strip inner integral conversions that do not change the precision. */
7994 /* Convert fabs((double)float) into (double)fabsf(float). */
7997 {
8002 targ0));
8003 }
8004 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8010 /* Strip sign ops from argument. */
8012 {
8016 }
8023 {
8028 }
8030 {
8035 }
8045 /* Convert ~ (-A) to A - 1. */
8050 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8058 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8071 /* Perform BIT_NOT_EXPR on each element individually. */
8073 {
8078 {
8080 {
8086 }
8087 else
8090 }
8093 }
8098 /* The argument to invert_truthvalue must have Boolean type. */
8102 /* Note that the operand of this must be an int
8103 and its values must be 0 or 1.
8104 ("true" is a fixed value perhaps depending on the language,
8105 but we don't handle values other than 1 correctly yet.) */
8120 {
8128 }
8130 {
8134 }
8136 {
8140 {
8149 }
8150 }
8162 {
8170 }
8172 {
8176 }
8178 {
8182 {
8191 }
8192 }
8198 }
8200 /* Fold a binary expression of code CODE and type TYPE with operands
8201 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8202 Return the folded expression if folding is successful. Otherwise,
8203 return NULL_TREE. */
8205 static tree
8207 {
8214 else
8217 /* MIN (MAX (a, b), b) == b. */
8222 /* MIN (MAX (b, a), b) == b. */
8228 /* MIN (a, MAX (a, b)) == a. */
8234 /* MIN (a, MAX (b, a)) == a. */
8241 }
8243 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8244 by changing CODE to reduce the magnitude of constants involved in
8245 ARG0 of the comparison.
8246 Returns a canonicalized comparison tree if a simplification was
8247 possible, otherwise returns NULL_TREE.
8248 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8249 valid if signed overflow is undefined. */
8251 static tree
8255 {
8261 /* Match A +- CST code arg1 and CST code arg1. */
8268 /* Identify the constant in arg0 and its sign. */
8271 else
8275 /* Overflowed constants and zero will cause problems. */
8280 /* See if we can reduce the magnitude of the constant in
8281 arg0 by changing the comparison code. */
8283 {
8284 /* CST <= arg1 -> CST-1 < arg1. */
8287 /* -CST < arg1 -> -CST-1 <= arg1. */
8290 /* CST > arg1 -> CST-1 >= arg1. */
8293 /* -CST >= arg1 -> -CST-1 > arg1. */
8296 else
8298 /* arg1 code' CST' might be more canonical. */
8300 }
8301 else
8302 {
8303 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8307 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8311 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8315 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8319 else
8322 }
8324 /* Now build the constant reduced in magnitude. */
8330 /* If swapping might yield to a more canonical form, do so. */
8333 else
8335 }
8337 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8338 overflow further. Try to decrease the magnitude of constants involved
8339 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8340 and put sole constants at the second argument position.
8341 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8343 static tree
8346 {
8347 tree t;
8352 /* In principle pointers also have undefined overflow behavior,
8353 but that causes problems elsewhere. */
8358 /* Try canonicalization by simplifying arg0. */
8363 {
8367 }
8369 /* Try canonicalization by simplifying arg1 using the swapped
8370 comparison. */
8378 }
8380 /* Subroutine of fold_binary. This routine performs all of the
8381 transformations that are common to the equality/inequality
8382 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8383 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8384 fold_binary should call fold_binary. Fold a comparison with
8385 tree code CODE and type TYPE with operands OP0 and OP1. Return
8386 the folded comparison or NULL_TREE. */
8388 static tree
8390 {
8403 /* If one arg is a real or integer constant, put it last. */
8407 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8414 {
8418 tree lhs;
8425 /* If the constant operation overflowed this can be
8426 simplified as a comparison against INT_MAX/INT_MIN. */
8429 {
8433 /* Get the sign of the constant on the lhs if the
8434 operation were VARIABLE + CONST1. */
8438 /* The sign of the constant determines if we overflowed
8439 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8440 Canonicalize to the INT_MIN overflow by swapping the comparison
8441 if necessary. */
8445 /* We now can look at the canonicalized case
8446 VARIABLE + 1 CODE2 INT_MIN
8447 and decide on the result. */
8456 }
8461 {
8463 "when changing X +- C1 cmp C2 to "
8465 WARN_STRICT_OVERFLOW_COMPARISON);
8467 }
8468 }
8470 /* For comparisons of pointers we can decompose it to a compile time
8471 comparison of the base objects and the offsets into the object.
8472 This requires at least one operand being an ADDR_EXPR or a
8473 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8479 {
8486 /* Get base and offset for the access. Strip ADDR_EXPR for
8487 get_inner_reference, but put it back by stripping INDIRECT_REF
8488 off the base object if possible. */
8491 {
8497 else
8499 }
8501 {
8504 }
8508 {
8512 /* We have to make sure to have an indirect/non-indirect base1
8513 just the same as we did for base0. */
8519 }
8521 {
8524 }
8528 /* If we have equivalent bases we might be able to simplify. */
8531 {
8532 /* We can fold this expression to a constant if the non-constant
8533 offset parts are equal. */
8537 {
8539 {
8553 }
8554 }
8555 /* We can simplify the comparison to a comparison of the variable
8556 offset parts if the constant offset parts are equal.
8557 Be careful to use signed size type here because otherwise we
8558 mess with array offsets in the wrong way. This is possible
8559 because pointer arithmetic is restricted to retain within an
8560 object and overflow on pointer differences is undefined as of
8561 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8563 {
8564 tree signed_size_type_node;
8567 /* By converting to signed size type we cover middle-end pointer
8568 arithmetic which operates on unsigned pointer types of size
8569 type size and ARRAY_REF offsets which are properly sign or
8570 zero extended from their type in case it is narrower than
8571 size type. */
8574 else
8578 else
8582 }
8583 }
8584 }
8586 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8587 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8588 the resulting offset is smaller in absolute value than the
8589 original one. */
8597 {
8602 tree cst;
8604 "occur when combining constants around "
8607 /* Put the constant on the side where it doesn't overflow and is
8608 of lower absolute value than before. */
8614 {
8617 variable1,
8620 }
8627 {
8632 variable2);
8633 }
8634 }
8636 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8637 signed arithmetic case. That form is created by the compiler
8638 often enough for folding it to be of value. One example is in
8639 computing loop trip counts after Operator Strength Reduction. */
8645 {
8654 "eliminating multiplication in comparison "
8656 WARN_STRICT_OVERFLOW_COMPARISON);
8658 /* If const1 is negative we swap the sense of the comparison. */
8663 }
8670 {
8678 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8683 /* (-a) CMP (-b) -> b CMP a */
8690 {
8691 REAL_VALUE_TYPE cst;
8694 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8701 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8702 /* a CMP (-0) -> a CMP 0 */
8707 /* x != NaN is always true, other ops are always false. */
8710 {
8713 }
8715 /* Fold comparisons against infinity. */
8717 {
8721 }
8722 }
8724 /* If this is a comparison of a real constant with a PLUS_EXPR
8725 or a MINUS_EXPR of a real constant, we can convert it into a
8726 comparison with a revised real constant as long as no overflow
8727 occurs when unsafe_math_optimizations are enabled. */
8739 /* Likewise, we can simplify a comparison of a real constant with
8740 a MINUS_EXPR whose first operand is also a real constant, i.e.
8741 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
8742 floating-point types only if -fassociative-math is set. */
8753 /* Fold comparisons against built-in math functions. */
8755 && flag_unsafe_math_optimizations
8757 {
8761 {
8765 }
8766 }
8767 }
8772 {
8773 /* If we are widening one operand of an integer comparison,
8774 see if the other operand is similarly being widened. Perhaps we
8775 can do the comparison in the narrower type. */
8780 /* Or if we are changing signedness. */
8784 }
8786 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8787 constant, we can simplify it. */
8792 {
8796 }
8798 /* Simplify comparison of something with itself. (For IEEE
8799 floating-point, we can only do some of these simplifications.) */
8801 {
8803 {
8818 /* For NE, we can only do this simplification if integer
8819 or we don't honor IEEE floating point NaNs. */
8823 /* ... fall through ... */
8829 }
8830 }
8832 /* If we are comparing an expression that just has comparisons
8833 of two integer values, arithmetic expressions of those comparisons,
8834 and constants, we can simplify it. There are only three cases
8835 to check: the two values can either be equal, the first can be
8836 greater, or the second can be greater. Fold the expression for
8837 those three values. Since each value must be 0 or 1, we have
8838 eight possibilities, each of which corresponds to the constant 0
8839 or 1 or one of the six possible comparisons.
8841 This handles common cases like (a > b) == 0 but also handles
8842 expressions like ((x > y) - (y > x)) > 0, which supposedly
8843 occur in macroized code. */
8846 {
8851 /* Don't handle degenerate cases here; they should already
8852 have been handled anyway. */
8861 {
8865 /* We can't just pass T to eval_subst in case cval1 or cval2
8866 was the same as ARG1. */
8868 tree high_result
8872 arg1);
8873 tree equal_result
8877 arg1);
8878 tree low_result
8882 arg1);
8884 /* All three of these results should be 0 or 1. Confirm they are.
8885 Then use those values to select the proper code to use. */
8890 {
8891 /* Make a 3-bit mask with the high-order bit being the
8892 value for `>', the next for '=', and the low for '<'. */
8896 {
8898 /* Always false. */
8919 /* Always true. */
8921 }
8926 }
8927 }
8928 }
8930 /* Fold a comparison of the address of COMPONENT_REFs with the same
8931 type and component to a comparison of the address of the base
8932 object. In short, &x->a OP &y->a to x OP y and
8933 &x->a OP &y.a to x OP &y */
8938 {
8942 {
8948 }
8949 }
8951 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8952 into a single range test. */
8960 {
8964 }
8966 /* Fold ~X op ~Y as Y op X. */
8969 {
8974 }
8976 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
8979 {
8985 }
8988 }
8991 /* Subroutine of fold_binary. Optimize complex multiplications of the
8992 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8993 argument EXPR represents the expression "z" of type TYPE. */
8995 static tree
8997 {
9002 {
9005 }
9007 {
9010 }
9011 else
9012 {
9016 }
9025 }
9028 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9029 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9030 guarantees that P and N have the same least significant log2(M) bits.
9031 N is not otherwise constrained. In particular, N is not normalized to
9032 0 <= N < M as is common. In general, the precise value of P is unknown.
9033 M is chosen as large as possible such that constant N can be determined.
9035 Returns M and sets *RESIDUE to N. */
9037 static unsigned HOST_WIDE_INT
9039 {
9046 {
9049 {
9051 tree offset;
9059 {
9062 else
9063 /* We don't handle more complicated offset expressions. */
9065 }
9066 }
9070 }
9072 {
9085 {
9088 }
9090 {
9093 {
9096 /* Compute the greatest power-of-2 divisor of op1. */
9100 /* If align is non-zero and less than *modulus, replace
9101 *modulus with align., If align is 0, then either op1 is 0
9102 or the greatest power-of-2 divisor of op1 doesn't fit in an
9103 unsigned HOST_WIDE_INT. In either case, no additional
9104 constraint is imposed. */
9109 }
9110 }
9111 }
9113 /* If we get here, we were unable to determine anything useful about the
9114 expression. */
9116 }
9119 /* Fold a binary expression of code CODE and type TYPE with operands
9120 OP0 and OP1. Return the folded expression if folding is
9121 successful. Otherwise, return NULL_TREE. */
9123 tree
9125 {
9140 /* Strip any conversions that don't change the mode. This is
9141 safe for every expression, except for a comparison expression
9142 because its signedness is derived from its operands. So, in
9143 the latter case, only strip conversions that don't change the
9144 signedness.
9146 Note that this is done as an internal manipulation within the
9147 constant folder, in order to find the simplest representation
9148 of the arguments so that their form can be studied. In any
9149 cases, the appropriate type conversions should be put back in
9150 the tree that will get out of the constant folder. */
9153 {
9156 }
9157 else
9158 {
9161 }
9163 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9164 constant but we can't do arithmetic on them. */
9171 {
9173 {
9174 /* Make sure type and arg0 have the same saturating flag. */
9178 }
9181 else
9185 {
9189 }
9190 }
9192 /* If this is a commutative operation, and ARG0 is a constant, move it
9193 to ARG1 to reduce the number of tests below. */
9198 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9200 First check for cases where an arithmetic operation is applied to a
9201 compound, conditional, or comparison operation. Push the arithmetic
9202 operation inside the compound or conditional to see if any folding
9203 can then be done. Convert comparison to conditional for this purpose.
9204 The also optimizes non-constant cases that used to be done in
9205 expand_expr.
9207 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9208 one of the operands is a comparison and the other is a comparison, a
9209 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9210 code below would make the expression more complex. Change it to a
9211 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9212 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9224 {
9228 boolean_type_node,
9236 }
9240 {
9246 op1));
9255 {
9261 }
9264 {
9270 }
9271 }
9274 {
9276 /* 0 +p index -> (type)index */
9280 /* PTR +p 0 -> PTR */
9284 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9291 /* index +p PTR -> PTR +p index */
9298 /* (PTR +p B) +p A -> PTR +p (B + A) */
9300 {
9301 tree inner;
9309 }
9311 /* PTR_CST +p CST -> CST1 */
9315 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9316 of the array. Loop optimizer sometimes produce this type of
9317 expressions. */
9319 {
9323 }
9328 /* PTR + INT -> (INT)(PTR p+ INT) */
9333 arg0,
9335 /* INT + PTR -> (INT)(PTR p+ INT) */
9340 arg1,
9342 /* A + (-B) -> A - B */
9347 /* (-A) + B -> B - A */
9355 {
9356 /* Convert ~A + 1 to -A. */
9361 /* ~X + X is -1. */
9364 {
9369 {
9372 }
9373 }
9375 /* X + ~X is -1. */
9378 {
9383 {
9386 }
9387 }
9389 /* X + (X / CST) * -CST is X % CST. */
9394 {
9402 }
9403 }
9405 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9406 same or one. Make sure type is not saturating.
9407 fold_plusminus_mult_expr will re-associate. */
9412 {
9416 }
9419 {
9423 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9424 with a constant, and the two constants have no bits in common,
9425 we should treat this as a BIT_IOR_EXPR since this may produce more
9426 simplifications. */
9434 {
9437 }
9439 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9440 (plus (plus (mult) (mult)) (foo)) so that we can
9441 take advantage of the factoring cases below. */
9448 {
9454 else
9476 parg1)));
9477 }
9478 }
9479 else
9480 {
9481 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9485 /* Likewise if the operands are reversed. */
9489 /* Convert X + -C into X - C. */
9492 {
9498 }
9500 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9501 to __complex__ ( x, y ). This is not the same for SNaNs or
9502 if signed zeros are involved. */
9506 {
9513 {
9517 {
9523 }
9525 {
9531 }
9532 }
9533 }
9541 /* Convert x+x into x*2.0. */
9547 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9548 We associate floats only if the user has specified
9549 -fassociative-math. */
9553 {
9558 {
9559 tree tree0;
9562 }
9563 }
9564 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9565 We associate floats only if the user has specified
9566 -fassociative-math. */
9570 {
9575 {
9576 tree tree0;
9579 }
9580 }
9581 }
9583 bit_rotate:
9584 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9585 is a rotate of A by C1 bits. */
9586 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9587 is a rotate of A by B bits. */
9588 {
9590 tree rtype;
9599 /* Only create rotates in complete modes. Other cases are not
9600 expanded properly. */
9602 {
9621 {
9629 TYPE_PRECISION
9634 ? LROTATE_EXPR
9637 }
9639 {
9647 TYPE_PRECISION
9652 ? LROTATE_EXPR
9655 }
9656 }
9657 }
9659 associate:
9660 /* In most languages, can't associate operations on floats through
9661 parentheses. Rather than remember where the parentheses were, we
9662 don't associate floats at all, unless the user has specified
9663 -fassociative-math.
9664 And, we need to make sure type is not saturating. */
9668 {
9673 /* Split both trees into variables, constants, and literals. Then
9674 associate each group together, the constants with literals,
9675 then the result with variables. This increases the chances of
9676 literals being recombined later and of generating relocatable
9677 expressions for the sum of a constant and literal. */
9682 /* With undefined overflow we can only associate constants
9683 with one variable. */
9687 {
9695 /* The only case we can still associate with two variables
9696 is if they are the same, modulo negation. */
9699 }
9701 /* Only do something if we found more than two objects. Otherwise,
9702 nothing has changed and we risk infinite recursion. */
9708 {
9709 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9718 /* Preserve the MINUS_EXPR if the negative part of the literal is
9719 greater than the positive part. Otherwise, the multiplicative
9720 folding code (i.e extract_muldiv) may be fooled in case
9721 unsigned constants are subtracted, like in the following
9722 example: ((X*2 + 4) - 8U)/2. */
9724 {
9728 {
9732 }
9733 else
9734 {
9738 }
9739 }
9741 {
9746 else
9747 {
9753 }
9754 }
9759 }
9760 }
9765 /* Pointer simplifications for subtraction, simple reassociations. */
9767 {
9768 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
9771 {
9779 }
9780 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
9782 {
9788 }
9789 }
9790 /* A - (-B) -> A + B */
9794 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9803 /* Convert -A - 1 to ~A. */
9811 /* Convert -1 - A to ~A. */
9817 /* X - (X / CST) * CST is X % CST. */
9830 {
9836 /* Fold A - (A & B) into ~B & A. */
9839 {
9841 {
9846 }
9848 {
9853 }
9854 }
9856 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
9857 any power of 2 minus 1. */
9862 {
9868 {
9872 }
9873 }
9874 }
9876 /* See if ARG1 is zero and X - ARG1 reduces to X. */
9880 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
9881 ARG0 is zero and X + ARG0 reduces to X, since that would mean
9882 (-ARG1 + ARG0) reduces to -ARG1. */
9886 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9887 __complex__ ( x, -y ). This is not the same for SNaNs or if
9888 signed zeros are involved. */
9892 {
9899 {
9903 {
9905 arg1r ? arg1r
9910 }
9912 {
9916 arg1i ? arg1i
9919 }
9920 }
9921 }
9923 /* Fold &x - &x. This can happen from &x.foo - &x.
9924 This is unsafe for certain floats even in non-IEEE formats.
9925 In IEEE, it is unsafe because it does wrong for NaNs.
9926 Also note that operand_equal_p is always false if an operand
9927 is volatile. */
9933 /* A - B -> A + (-B) if B is easily negatable. */
9936 /* Avoid this transformation if B is a positive REAL_CST. */
9944 /* Try folding difference of addresses. */
9945 {
9946 HOST_WIDE_INT diff;
9952 }
9954 /* Fold &a[i] - &a[j] to i-j. */
9959 {
9964 {
9972 }
9973 }
9981 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
9982 same or one. Make sure type is not saturating.
9983 fold_plusminus_mult_expr will re-associate. */
9988 {
9992 }
9997 /* (-A) * (-B) -> A * B */
10008 {
10013 /* Transform x * -1 into -x. Make sure to do the negation
10014 on the original operand with conversions not stripped
10015 because we can only strip non-sign-changing conversions. */
10018 /* Transform x * -C into -x * C if x is easily negatable. */
10027 /* (a * (1 << b)) is (a << b) */
10041 {
10044 "occur when simplifying "
10046 WARN_STRICT_OVERFLOW_MISC);
10048 }
10050 /* Optimize z * conj(z) for integer complex numbers. */
10057 }
10058 else
10059 {
10060 /* Maybe fold x * 0 to 0. The expressions aren't the same
10061 when x is NaN, since x * 0 is also NaN. Nor are they the
10062 same in modes with signed zeros, since multiplying a
10063 negative value by 0 gives -0, not +0. */
10068 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10073 /* Transform x * -1.0 into -x. */
10078 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10079 the result for floating point types due to rounding so it is applied
10080 only if -fassociative-math was specify. */
10085 {
10091 }
10093 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10095 {
10098 {
10101 }
10102 }
10104 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10105 This is not the same for NaNs or if signed zeros are
10106 involved. */
10112 {
10124 }
10126 /* Optimize z * conj(z) for floating point complex numbers.
10127 Guarded by flag_unsafe_math_optimizations as non-finite
10128 imaginary components don't produce scalar results. */
10139 {
10143 /* Optimizations of root(...)*root(...). */
10145 {
10150 /* Optimize sqrt(x)*sqrt(x) as x. */
10156 /* Optimize root(x)*root(y) as root(x*y). */
10160 }
10162 /* Optimize expN(x)*expN(y) as expN(x+y). */
10164 {
10170 }
10172 /* Optimizations of pow(...)*pow(...). */
10176 {
10182 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10184 {
10188 }
10190 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10192 {
10196 }
10197 }
10199 /* Optimize tan(x)*cos(x) as sin(x). */
10208 {
10213 }
10215 /* Optimize x*pow(x,c) as pow(x,c+1). */
10219 {
10225 {
10227 REAL_VALUE_TYPE c;
10228 tree arg;
10234 }
10235 }
10237 /* Optimize pow(x,c)*x as pow(x,c+1). */
10241 {
10247 {
10249 REAL_VALUE_TYPE c;
10250 tree arg;
10256 }
10257 }
10259 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10262 {
10266 {
10269 }
10270 }
10271 }
10272 }
10276 bit_ior:
10284 /* ~X | X is -1. */
10287 {
10291 }
10293 /* X | ~X is -1. */
10296 {
10300 }
10302 /* Canonicalize (X & C1) | C2. */
10306 {
10314 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10319 {
10323 }
10324 else
10325 {
10329 }
10331 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10336 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10337 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10338 mode which allows further optimizations. */
10348 {
10349 unsigned HOST_WIDE_INT mask
10353 {
10357 }
10358 }
10365 arg1);
10366 }
10368 /* (X & Y) | Y is (X, Y). */
10372 /* (X & Y) | X is (Y, X). */
10377 /* X | (X & Y) is (Y, X). */
10382 /* X | (Y & X) is (Y, X). */
10392 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10394 This results in more efficient code for machines without a NAND
10395 instruction. Combine will canonicalize to the first form
10396 which will allow use of NAND instructions provided by the
10397 backend if they exist. */
10400 {
10405 }
10407 /* See if this can be simplified into a rotate first. If that
10408 is unsuccessful continue in the association code. */
10419 /* ~X ^ X is -1. */
10422 {
10426 }
10428 /* X ^ ~X is -1. */
10431 {
10435 }
10437 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10438 with a constant, and the two constants have no bits in common,
10439 we should treat this as a BIT_IOR_EXPR since this may produce more
10440 simplifications. */
10448 {
10451 }
10453 /* (X | Y) ^ X -> Y & ~ X*/
10456 {
10459 arg1);
10463 }
10465 /* (Y | X) ^ X -> Y & ~ X*/
10468 {
10471 arg1);
10475 }
10477 /* X ^ (X | Y) -> Y & ~ X*/
10480 {
10483 arg0);
10487 }
10489 /* X ^ (Y | X) -> Y & ~ X*/
10492 {
10495 arg0);
10499 }
10501 /* Convert ~X ^ ~Y to X ^ Y. */
10508 /* Convert ~X ^ C to X ^ ~C. */
10515 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10522 /* Fold (X & Y) ^ Y as ~X & Y. */
10525 {
10530 }
10531 /* Fold (X & Y) ^ X as ~Y & X. */
10535 {
10540 }
10541 /* Fold X ^ (X & Y) as X & ~Y. */
10544 {
10549 }
10550 /* Fold X ^ (Y & X) as ~Y & X. */
10554 {
10559 }
10561 /* See if this can be simplified into a rotate first. If that
10562 is unsuccessful continue in the association code. */
10573 /* ~X & X is always zero. */
10578 /* X & ~X is always zero. */
10583 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10587 {
10596 }
10598 /* (X | Y) & Y is (X, Y). */
10602 /* (X | Y) & X is (Y, X). */
10607 /* X & (X | Y) is (Y, X). */
10612 /* X & (Y | X) is (Y, X). */
10618 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10622 {
10628 }
10629 /* Fold ~X & 1 as (X & 1) == 0. */
10632 {
10638 }
10640 /* Fold (X ^ Y) & Y as ~X & Y. */
10643 {
10648 }
10649 /* Fold (X ^ Y) & X as ~Y & X. */
10653 {
10658 }
10659 /* Fold X & (X ^ Y) as X & ~Y. */
10662 {
10667 }
10668 /* Fold X & (Y ^ X) as ~Y & X. */
10672 {
10677 }
10682 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10685 {
10686 unsigned int prec
10693 }
10695 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10697 This results in more efficient code for machines without a NOR
10698 instruction. Combine will canonicalize to the first form
10699 which will allow use of NOR instructions provided by the
10700 backend if they exist. */
10703 {
10710 }
10712 /* If arg0 is derived from the address of an object or function, we may
10713 be able to fold this expression using the object or function's
10714 alignment. */
10716 {
10722 /* This works because modulus is a power of 2. If this weren't the
10723 case, we'd have to replace it by its greatest power-of-2
10724 divisor: modulus & -modulus. */
10727 }
10729 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
10730 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
10731 if the new mask might be further optimized. */
10740 {
10742 unsigned HOST_WIDE_INT mask
10752 {
10755 /* See if more bits can be proven as zero because of
10756 zero extension. */
10759 {
10764 {
10766 /* See if we can shorten the right shift. */
10769 }
10770 }
10774 /* For arithmetic shift if sign bit could be set, zerobits
10775 can contain actually sign bits, so no transformation is
10776 possible, unless MASK masks them all away. In that
10777 case the shift needs to be converted into logical shift. */
10780 {
10783 else
10785 }
10786 }
10788 /* ((X << 16) & 0xff00) is (X, 0). */
10794 {
10797 /* Only do the transformation if NEWMASK is some integer
10798 mode's mask. */
10805 {
10807 {
10813 }
10814 else
10818 newmask));
10819 }
10820 }
10821 }
10826 /* Don't touch a floating-point divide by zero unless the mode
10827 of the constant can represent infinity. */
10833 /* Optimize A / A to 1.0 if we don't care about
10834 NaNs or Infinities. Skip the transformation
10835 for non-real operands. */
10840 {
10844 }
10846 /* The complex version of the above A / A optimization. */
10849 {
10853 {
10855 /* omit_two_operands will call fold_convert for us. */
10857 }
10858 }
10860 /* (-A) / (-B) -> A / B */
10870 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
10875 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
10880 /* If ARG1 is a constant, we can convert this to a multiply by the
10881 reciprocal. This does not have the same rounding properties,
10882 so only do this if -freciprocal-math. We can actually
10883 always safely do it if ARG1 is a power of two, but it's hard to
10884 tell if it is or not in a portable manner. */
10886 {
10891 /* Find the reciprocal if optimizing and the result is exact. */
10893 {
10894 REAL_VALUE_TYPE r;
10897 {
10901 }
10902 }
10903 }
10904 /* Convert A/B/C to A/(B*C). */
10911 /* Convert A/(B/C) to (A/B)*C. */
10919 /* Convert C1/(X*C2) into (C1/C2)/X. */
10924 {
10930 }
10933 {
10937 /* Optimize sin(x)/cos(x) as tan(x). */
10943 {
10948 }
10950 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
10956 {
10960 {
10964 }
10965 }
10967 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
10968 NaNs or Infinities. */
10972 {
10979 {
10984 }
10985 }
10987 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
10988 NaNs or Infinities. */
10992 {
10999 {
11003 {
11007 tmp);
11008 }
11009 }
11010 }
11012 /* Optimize pow(x,c)/x as pow(x,c-1). */
11016 {
11022 {
11024 REAL_VALUE_TYPE c;
11025 tree arg;
11031 }
11032 }
11034 /* Optimize a/root(b/c) into a*root(c/b). */
11036 {
11040 {
11049 }
11050 }
11052 /* Optimize x/expN(y) into x*expN(-y). */
11054 {
11059 }
11061 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11065 {
11072 }
11073 }
11078 /* Simplify A / (B << N) where A and B are positive and B is
11079 a power of 2, to A >> (N + log2(B)). */
11084 {
11087 {
11094 WARN_STRICT_OVERFLOW_MISC);
11100 }
11101 }
11103 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11104 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11110 /* Fall thru */
11119 /* X / -1 is -X. */
11126 /* Convert -A / -B to A / B when the type is signed and overflow is
11127 undefined. */
11131 {
11134 "when distributing negation across "
11136 WARN_STRICT_OVERFLOW_MISC);
11140 }
11144 {
11147 "when distributing negation across "
11149 WARN_STRICT_OVERFLOW_MISC);
11152 }
11154 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11155 operation, EXACT_DIV_EXPR.
11157 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11158 At one time others generated faster code, it's not clear if they do
11159 after the last round to changes to the DIV code in expmed.c. */
11168 {
11172 WARN_STRICT_OVERFLOW_MISC);
11174 }
11182 /* X % 1 is always zero, but be sure to preserve any side
11183 effects in X. */
11187 /* X % 0, return X % 0 unchanged so that we can get the
11188 proper warnings and errors. */
11192 /* 0 % X is always zero, but be sure to preserve any side
11193 effects in X. Place this after checking for X == 0. */
11197 /* X % -1 is zero. */
11204 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11205 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11210 {
11212 /* Also optimize A % (C << N) where C is a power of 2,
11213 to A & ((C << N) - 1). */
11218 {
11223 "occur when simplifying "
11225 WARN_STRICT_OVERFLOW_MISC);
11229 }
11230 }
11232 /* X % -C is the same as X % C. */
11239 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11244 /* X % -Y is the same as X % Y. */
11255 {
11259 WARN_STRICT_OVERFLOW_MISC);
11261 }
11272 /* Optimize -1 >> x for arithmetic right shifts. */
11275 /* ... fall through ... */
11278 shift:
11284 /* Since negative shift count is not well-defined,
11285 don't try to compute it in the compiler. */
11289 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11294 {
11298 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11299 being well defined. */
11301 {
11306 else
11308 }
11312 }
11314 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11315 into x & ((unsigned)-1 >> c) for unsigned types. */
11323 {
11326 tree lshift;
11327 tree arg00;
11330 {
11337 }
11338 }
11340 /* Rewrite an LROTATE_EXPR by a constant into an
11341 RROTATE_EXPR by a new constant. */
11343 {
11348 }
11350 /* If we have a rotate of a bit operation with the rotate count and
11351 the second operand of the bit operation both constant,
11352 permute the two operations. */
11364 /* Two consecutive rotates adding up to the precision of the
11365 type can be ignored. */
11376 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11377 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11378 if the latter can be further optimized. */
11383 {
11386 arg1);
11389 arg1);
11393 }
11421 /* Note that the operands of this must be ints
11422 and their values must be 0 or 1.
11423 ("true" is a fixed value perhaps depending on the language.) */
11424 /* If first arg is constant zero, return it. */
11428 /* If either arg is constant true, drop it. */
11432 /* Preserve sequence points. */
11435 /* If second arg is constant zero, result is zero, but first arg
11436 must be evaluated. */
11439 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11440 case will be handled here. */
11444 /* !X && X is always false. */
11448 /* X && !X is always false. */
11453 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11454 means A >= Y && A != MAX, but in this case we know that
11455 A < X <= MAX. */
11459 {
11467 }
11469 truth_andor:
11470 /* We only do these simplifications if we are optimizing. */
11474 /* Check for things like (A || B) && (A || C). We can convert this
11475 to A || (B && C). Note that either operator can be any of the four
11476 truth and/or operations and the transformation will still be
11477 valid. Also note that we only care about order for the
11478 ANDIF and ORIF operators. If B contains side effects, this
11479 might change the truth-value of A. */
11486 {
11506 /* This case if tricky because we must either have commutative
11507 operators or else A10 must not have side-effects. */
11513 a01);
11514 }
11516 /* See if we can build a range comparison. */
11520 /* Check for the possibility of merging component references. If our
11521 lhs is another similar operation, try to merge its rhs with our
11522 rhs. Then try to merge our lhs and rhs. */
11534 /* Note that the operands of this must be ints
11535 and their values must be 0 or true.
11536 ("true" is a fixed value perhaps depending on the language.) */
11537 /* If first arg is constant true, return it. */
11541 /* If either arg is constant zero, drop it. */
11545 /* Preserve sequence points. */
11548 /* If second arg is constant true, result is true, but we must
11549 evaluate first arg. */
11552 /* Likewise for first arg, but note this only occurs here for
11553 TRUTH_OR_EXPR. */
11557 /* !X || X is always true. */
11561 /* X || !X is always true. */
11569 /* If the second arg is constant zero, drop it. */
11572 /* If the second arg is constant true, this is a logical inversion. */
11574 {
11575 /* Only call invert_truthvalue if operand is a truth value. */
11578 else
11581 }
11582 /* Identical arguments cancel to zero. */
11586 /* !X ^ X is always true. */
11591 /* X ^ !X is always true. */
11604 /* bool_var != 0 becomes bool_var. */
11609 /* bool_var == 1 becomes bool_var. */
11614 /* bool_var != 1 becomes !bool_var. */
11619 /* bool_var == 0 becomes !bool_var. */
11624 /* If this is an equality comparison of the address of two non-weak,
11625 unaliased symbols neither of which are extern (since we do not
11626 have access to attributes for externs), then we know the result. */
11639 {
11640 /* We know that we're looking at the address of two
11641 non-weak, unaliased, static _DECL nodes.
11643 It is both wasteful and incorrect to call operand_equal_p
11644 to compare the two ADDR_EXPR nodes. It is wasteful in that
11645 all we need to do is test pointer equality for the arguments
11646 to the two ADDR_EXPR nodes. It is incorrect to use
11647 operand_equal_p as that function is NOT equivalent to a
11648 C equality test. It can in fact return false for two
11649 objects which would test as equal using the C equality
11650 operator. */
11654 type);
11655 }
11657 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11658 a MINUS_EXPR of a constant, we can convert it into a comparison with
11659 a revised constant as long as no overflow occurs. */
11671 /* Similarly for a NEGATE_EXPR. */
11679 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11688 /* Transform comparisons of the form X +- C CMP X. */
11694 {
11701 else
11704 }
11706 /* If we have X - Y == 0, we can convert that to X == Y and similarly
11707 for !=. Don't do this for ordered comparisons due to overflow. */
11713 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11718 /* If this is an EQ or NE comparison with zero and ARG0 is
11719 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11720 two operations, but the latter can be done in one less insn
11721 on machines that have only two-operand insns or on which a
11722 constant cannot be the first operand. */
11725 {
11730 {
11737 }
11740 {
11747 }
11748 }
11750 /* If this is an NE or EQ comparison of zero against the result of a
11751 signed MOD operation whose second operand is a power of 2, make
11752 the MOD operation unsigned since it is simpler and equivalent. */
11760 {
11770 }
11772 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11773 C1 is a valid shift constant, and C2 is a power of two, i.e.
11774 a single bit. */
11778 == INTEGER_CST
11781 {
11786 /* Check for a valid shift count. */
11789 {
11793 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11794 can be rewritten as (X & (C2 << C1)) != 0. */
11796 {
11800 }
11801 /* Otherwise, for signed (arithmetic) shifts,
11802 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11803 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11807 /* Otherwise, of unsigned (logical) shifts,
11808 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11809 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11810 else
11814 arg000);
11815 }
11816 }
11818 /* If this is an NE comparison of zero with an AND of one, remove the
11819 comparison since the AND will give the correct value. */
11826 /* If we have (A & C) == C where C is a power of 2, convert this into
11827 (A & C) != 0. Similarly for NE_EXPR. */
11833 integer_zero_node));
11835 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
11836 bit, then fold the expression into A < 0 or A >= 0. */
11841 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
11842 Similarly for NE_EXPR. */
11846 {
11855 }
11857 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
11858 Similarly for NE_EXPR. */
11862 {
11869 }
11871 /* Optimize comparisons of strlen vs zero to a compare of the
11872 first character of the string vs zero. To wit,
11873 strlen(ptr) == 0 => *ptr == 0
11874 strlen(ptr) != 0 => *ptr != 0
11875 Other cases should reduce to one of these two (or a constant)
11876 due to the return value of strlen being unsigned. */
11879 {
11887 {
11891 }
11892 }
11894 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
11895 of X. Similarly fold (X >> C) == 0 into X >= 0. */
11899 {
11906 {
11908 {
11911 }
11914 }
11915 }
11917 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
11923 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
11928 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
11935 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
11943 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
11944 (X & C) == 0 when C is a single bit. */
11949 {
11955 }
11957 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
11958 constant C is a power of two, i.e. a single bit. */
11965 {
11969 }
11971 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
11972 when is C is a power of two, i.e. a single bit. */
11979 {
11985 }
11989 {
11992 }
11994 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12001 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12004 {
12016 arg01),
12024 arg01),
12032 arg00),
12040 arg00),
12042 }
12046 {
12053 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12054 operand_equal_p guarantees no side-effects so we don't need
12055 to use omit_one_operand on Z. */
12065 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12072 arg10);
12073 }
12075 /* Attempt to simplify equality/inequality comparisons of complex
12076 values. Only lower the comparison if the result is known or
12077 can be simplified to a single scalar comparison. */
12082 {
12087 {
12090 }
12091 else
12092 {
12095 }
12098 {
12101 }
12102 else
12103 {
12106 }
12110 {
12112 {
12117 }
12118 else
12119 {
12124 }
12125 }
12129 {
12131 {
12136 }
12137 else
12138 {
12143 }
12144 }
12145 }
12157 /* Transform comparisons of the form X +- C CMP X. */
12164 {
12171 else
12174 /* (X - c) > X becomes false. */
12178 {
12182 "occur when assuming that (X - c) > X "
12184 WARN_STRICT_OVERFLOW_ALL);
12186 }
12188 /* Likewise (X + c) < X becomes false. */
12192 {
12196 "occur when assuming that "
12198 WARN_STRICT_OVERFLOW_ALL);
12200 }
12202 /* Convert (X - c) <= X to true. */
12207 {
12211 "occur when assuming that "
12213 WARN_STRICT_OVERFLOW_ALL);
12215 }
12217 /* Convert (X + c) >= X to true. */
12222 {
12226 "occur when assuming that "
12228 WARN_STRICT_OVERFLOW_ALL);
12230 }
12233 {
12234 /* Convert X + c > X and X - c < X to true for integers. */
12238 {
12241 "not occur when assuming that "
12243 WARN_STRICT_OVERFLOW_ALL);
12245 }
12250 {
12253 "not occur when assuming that "
12255 WARN_STRICT_OVERFLOW_ALL);
12257 }
12259 /* Convert X + c <= X and X - c >= X to false for integers. */
12263 {
12266 "not occur when assuming that "
12268 WARN_STRICT_OVERFLOW_ALL);
12270 }
12275 {
12278 "not occur when assuming that "
12280 WARN_STRICT_OVERFLOW_ALL);
12282 }
12283 }
12284 }
12286 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
12287 This transformation affects the cases which are handled in later
12288 optimizations involving comparisons with non-negative constants. */
12292 {
12294 {
12299 }
12301 {
12306 }
12307 }
12309 /* Comparisons with the highest or lowest possible integer of
12310 the specified precision will have known values. */
12311 {
12319 {
12320 HOST_WIDE_INT signed_max_hi;
12325 {
12332 {
12336 }
12337 else
12338 {
12342 }
12343 }
12344 else
12345 {
12354 {
12357 }
12358 else
12359 {
12362 }
12363 }
12368 {
12381 /* The GE_EXPR and LT_EXPR cases above are not normally
12382 reached because of previous transformations. */
12386 }
12388 == max_hi
12391 {
12397 arg1);
12403 arg1);
12406 }
12408 == min_hi
12411 {
12426 }
12428 == min_hi
12431 {
12436 arg1);
12441 arg1);
12444 }
12449 /* We will flip the signedness of the comparison operator
12450 associated with the mode of arg1, so the sign bit is
12451 specified by this mode. Check that arg1 is the signed
12452 max associated with this sign bit. */
12454 /* signed_type does not work on pointer types. */
12456 {
12457 /* The following case also applies to X < signed_max+1
12458 and X >= signed_max+1 because previous transformations. */
12460 {
12461 tree st;
12466 }
12467 }
12468 }
12469 }
12471 /* If we are comparing an ABS_EXPR with a constant, we can
12472 convert all the cases into explicit comparisons, but they may
12473 well not be faster than doing the ABS and one comparison.
12474 But ABS (X) <= C is a range comparison, which becomes a subtraction
12475 and a comparison, and is probably faster. */
12489 /* Convert ABS_EXPR<x> >= 0 to true. */
12496 {
12499 "when simplifying comparison of "
12501 WARN_STRICT_OVERFLOW_CONDITIONAL);
12503 }
12505 /* Convert ABS_EXPR<x> < 0 to false. */
12510 {
12513 "when simplifying comparison of "
12515 WARN_STRICT_OVERFLOW_CONDITIONAL);
12517 }
12519 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12520 and similarly for >= into !=. */
12536 return
12555 {
12559 }
12561 /* If the first operand is NaN, the result is constant. */
12565 {
12567 ? integer_zero_node
12570 }
12572 /* If the second operand is NaN, the result is constant. */
12576 {
12578 ? integer_zero_node
12581 }
12583 /* Simplify unordered comparison of something with itself. */
12589 && !flag_trapping_math
12593 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12594 {
12605 }
12610 /* When pedantic, a compound expression can be neither an lvalue
12611 nor an integer constant expression. */
12614 /* Don't let (0, 0) be null pointer constant. */
12628 /* An ASSERT_EXPR should never be passed to fold_binary. */
12634 }
12636 /* Callback for walk_tree, looking for LABEL_EXPR.
12637 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12638 Do not check the sub-tree of GOTO_EXPR. */
12640 static tree
12644 {
12646 {
12651 /* no break */
12654 }
12655 }
12657 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12658 accessible from outside the sub-tree. Returns NULL_TREE if no
12659 addressable label is found. */
12661 static bool
12663 {
12665 }
12667 /* Fold a ternary expression of code CODE and type TYPE with operands
12668 OP0, OP1, and OP2. Return the folded expression if folding is
12669 successful. Otherwise, return NULL_TREE. */
12671 tree
12673 {
12674 tree tem;
12681 /* Strip any conversions that don't change the mode. This is safe
12682 for every expression, except for a comparison expression because
12683 its signedness is derived from its operands. So, in the latter
12684 case, only strip conversions that don't change the signedness.
12686 Note that this is done as an internal manipulation within the
12687 constant folder, in order to find the simplest representation of
12688 the arguments so that their form can be studied. In any cases,
12689 the appropriate type conversions should be put back in the tree
12690 that will get out of the constant folder. */
12692 {
12695 }
12698 {
12701 }
12704 {
12708 {
12714 }
12718 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12719 so all simple results must be passed through pedantic_non_lvalue. */
12721 {
12724 /* Only optimize constant conditions when the selected branch
12725 has the same type as the COND_EXPR. This avoids optimizing
12726 away "c ? x : throw", where the throw has a void type.
12727 Avoid throwing away that operand which contains label. */
12734 }
12738 /* If we have A op B ? A : C, we may be able to convert this to a
12739 simpler expression, depending on the operation and the values
12740 of B and C. Signed zeros prevent all of these transformations,
12741 for reasons given above each one.
12743 Also try swapping the arguments and inverting the conditional. */
12748 {
12752 }
12756 op2,
12759 {
12762 {
12766 }
12767 }
12769 /* If the second operand is simpler than the third, swap them
12770 since that produces better jump optimization results. */
12773 {
12774 /* See if this can be inverted. If it can't, possibly because
12775 it was a floating-point inequality comparison, don't do
12776 anything. */
12780 }
12782 /* Convert A ? 1 : 0 to simply A. */
12785 /* If we try to convert OP0 to our type, the
12786 call to fold will try to move the conversion inside
12787 a COND, which will recurse. In that case, the COND_EXPR
12788 is probably the best choice, so leave it alone. */
12792 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12793 over COND_EXPR in cases such as floating point comparisons. */
12800 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12805 {
12806 /* sign_bit_p only checks ARG1 bits within A's precision.
12807 If <sign bit of A> has wider type than A, bits outside
12808 of A's precision in <sign bit of A> need to be checked.
12809 If they are all 0, this optimization needs to be done
12810 in unsigned A's type, if they are all 1 in signed A's type,
12811 otherwise this can't be done. */
12816 {
12818 HOST_WIDE_INT mask_hi;
12820 tree tem_type;
12828 {
12832 }
12833 else
12834 {
12838 }
12840 {
12844 }
12845 else
12851 {
12854 }
12857 {
12860 }
12861 else
12863 }
12870 arg1)));
12871 }
12873 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12874 already handled above. */
12879 {
12888 }
12890 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12891 is probably obsolete because the first operand should be a
12892 truth value (that's why we have the two cases above), but let's
12893 leave it in until we can confirm this for all front-ends. */
12904 /* Convert A ? B : 0 into A && B if A and B are truth values. */
12910 arg1);
12912 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
12916 {
12917 /* Only perform transformation if ARG0 is easily inverted. */
12922 arg1);
12923 }
12925 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
12929 {
12930 /* Only perform transformation if ARG0 is easily inverted. */
12935 op2);
12936 }
12938 /* Convert A ? 1 : B into A || B if A and B are truth values. */
12944 op2);
12949 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
12950 of fold_ternary on them. */
12957 {
12966 {
12971 else
12972 {
12974 tree value;
12978 }
12983 else
12985 }
12986 }
12992 }
12994 /* Perform constant folding and related simplification of EXPR.
12995 The related simplifications include x*1 => x, x*0 => 0, etc.,
12996 and application of the associative law.
12997 NOP_EXPR conversions may be removed freely (as long as we
12998 are careful not to change the type of the overall expression).
12999 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13000 but we can constant-fold them if they have constant operands. */
13002 #ifdef ENABLE_FOLD_CHECKING
13003 # define fold(x) fold_1 (x)
13005 static
13006 #endif
13007 tree
13009 {
13013 tree tem;
13015 /* Return right away if a constant. */
13019 /* CALL_EXPR-like objects with variable numbers of operands are
13020 treated specially. */
13022 {
13024 {
13027 }
13029 }
13033 {
13038 {
13056 }
13057 }
13060 {
13067 }
13069 #ifdef ENABLE_FOLD_CHECKING
13070 #undef fold
13076 /* When --enable-checking=fold, compute a digest of expr before
13077 and after actual fold call to see if fold did not accidentally
13078 change original expr. */
13080 tree
13082 {
13083 tree ret;
13086 htab_t ht;
13105 }
13107 void
13109 {
13112 htab_t ht;
13122 }
13124 static void
13126 {
13128 }
13130 static void
13132 {
13138 recursive_label:
13152 {
13153 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13157 }
13162 {
13163 /* Allow these fields to be modified. */
13164 tree tmp;
13171 {
13174 }
13175 }
13184 {
13187 {
13201 }
13205 {
13218 }
13235 {
13241 }
13246 {
13250 }
13261 {
13264 }
13274 }
13275 }
13277 /* Helper function for outputting the checksum of a tree T. When
13278 debugging with gdb, you can "define mynext" to be "next" followed
13279 by "call debug_fold_checksum (op0)", then just trace down till the
13280 outputs differ. */
13282 void
13284 {
13299 }
13301 #endif
13303 /* Fold a unary tree expression with code CODE of type TYPE with an
13304 operand OP0. Return a folded expression if successful. Otherwise,
13305 return a tree expression with code CODE of type TYPE with an
13306 operand OP0. */
13308 tree
13310 {
13311 tree tem;
13312 #ifdef ENABLE_FOLD_CHECKING
13315 htab_t ht;
13322 #endif
13328 #ifdef ENABLE_FOLD_CHECKING
13336 #endif
13338 }
13340 /* Fold a binary tree expression with code CODE of type TYPE with
13341 operands OP0 and OP1. Return a folded expression if successful.
13342 Otherwise, return a tree expression with code CODE of type TYPE
13343 with operands OP0 and OP1. */
13345 tree
13347 MEM_STAT_DECL)
13348 {
13349 tree tem;
13350 #ifdef ENABLE_FOLD_CHECKING
13356 htab_t ht;
13368 #endif
13374 #ifdef ENABLE_FOLD_CHECKING
13390 #endif
13392 }
13394 /* Fold a ternary tree expression with code CODE of type TYPE with
13395 operands OP0, OP1, and OP2. Return a folded expression if
13396 successful. Otherwise, return a tree expression with code CODE of
13397 type TYPE with operands OP0, OP1, and OP2. */
13399 tree
13401 MEM_STAT_DECL)
13402 {
13403 tree tem;
13404 #ifdef ENABLE_FOLD_CHECKING
13412 htab_t ht;
13429 #endif
13436 #ifdef ENABLE_FOLD_CHECKING
13460 #endif
13462 }
13464 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13465 arguments in ARGARRAY, and a null static chain.
13466 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13467 of type TYPE from the given operands as constructed by build_call_array. */
13469 tree
13471 {
13472 tree tem;
13473 #ifdef ENABLE_FOLD_CHECKING
13479 htab_t ht;
13493 #endif
13497 #ifdef ENABLE_FOLD_CHECKING
13514 #endif
13516 }
13518 /* Perform constant folding and related simplification of initializer
13519 expression EXPR. These behave identically to "fold_buildN" but ignore
13520 potential run-time traps and exceptions that fold must preserve. */
13522 #define START_FOLD_INIT \
13523 int saved_signaling_nans = flag_signaling_nans;\
13524 int saved_trapping_math = flag_trapping_math;\
13525 int saved_rounding_math = flag_rounding_math;\
13526 int saved_trapv = flag_trapv;\
13527 int saved_folding_initializer = folding_initializer;\
13528 flag_signaling_nans = 0;\
13529 flag_trapping_math = 0;\
13530 flag_rounding_math = 0;\
13531 flag_trapv = 0;\
13532 folding_initializer = 1;
13534 #define END_FOLD_INIT \
13535 flag_signaling_nans = saved_signaling_nans;\
13536 flag_trapping_math = saved_trapping_math;\
13537 flag_rounding_math = saved_rounding_math;\
13538 flag_trapv = saved_trapv;\
13539 folding_initializer = saved_folding_initializer;
13541 tree
13543 {
13544 tree result;
13545 START_FOLD_INIT;
13549 END_FOLD_INIT;
13551 }
13553 tree
13555 {
13556 tree result;
13557 START_FOLD_INIT;
13561 END_FOLD_INIT;
13563 }
13565 tree
13567 tree op2)
13568 {
13569 tree result;
13570 START_FOLD_INIT;
13574 END_FOLD_INIT;
13576 }
13578 tree
13581 {
13582 tree result;
13583 START_FOLD_INIT;
13587 END_FOLD_INIT;
13589 }
13591 #undef START_FOLD_INIT
13592 #undef END_FOLD_INIT
13594 /* Determine if first argument is a multiple of second argument. Return 0 if
13595 it is not, or we cannot easily determined it to be.
13597 An example of the sort of thing we care about (at this point; this routine
13598 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13599 fold cases do now) is discovering that
13601 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13603 is a multiple of
13605 SAVE_EXPR (J * 8)
13607 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13609 This code also handles discovering that
13611 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13613 is a multiple of 8 so we don't have to worry about dealing with a
13614 possible remainder.
13616 Note that we *look* inside a SAVE_EXPR only to determine how it was
13617 calculated; it is not safe for fold to do much of anything else with the
13618 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13619 at run time. For example, the latter example above *cannot* be implemented
13620 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13621 evaluation time of the original SAVE_EXPR is not necessarily the same at
13622 the time the new expression is evaluated. The only optimization of this
13623 sort that would be valid is changing
13625 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13627 divided by 8 to
13629 SAVE_EXPR (I) * SAVE_EXPR (J)
13631 (where the same SAVE_EXPR (J) is used in the original and the
13632 transformed version). */
13634 int
13636 {
13644 {
13646 /* Bitwise and provides a power of two multiple. If the mask is
13647 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13650 /* FALLTHRU */
13663 {
13667 /* const_binop may not detect overflow correctly,
13668 so check for it explicitly here. */
13674 size_one_node,
13678 }
13682 /* Can't handle conversions from non-integral or wider integral type. */
13688 /* .. fall through ... */
13705 }
13706 }
13708 /* Return true if CODE or TYPE is known to be non-negative. */
13710 static bool
13712 {
13715 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13716 have a signed:1 type (where the value is -1 and 0). */
13719 }
13721 /* Return true if (CODE OP0) is known to be non-negative. If the return
13722 value is based on the assumption that signed overflow is undefined,
13723 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13724 *STRICT_OVERFLOW_P. */
13726 static bool
13729 {
13734 {
13736 /* We can't return 1 if flag_wrapv is set because
13737 ABS_EXPR<INT_MIN> = INT_MIN. */
13741 {
13744 }
13751 strict_overflow_p);
13754 {
13759 {
13762 strict_overflow_p);
13764 {
13768 strict_overflow_p);
13769 }
13770 }
13772 {
13775 strict_overflow_p);
13779 }
13780 }
13785 }
13787 /* We don't know sign of `t', so be conservative and return false. */
13789 }
13791 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13792 value is based on the assumption that signed overflow is undefined,
13793 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13794 *STRICT_OVERFLOW_P. */
13796 static bool
13799 {
13804 {
13809 strict_overflow_p)
13811 strict_overflow_p));
13813 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13814 both unsigned and at least 2 bits shorter than the result. */
13818 {
13823 {
13827 }
13828 }
13833 {
13834 /* x * x for floating point x is always non-negative. */
13838 strict_overflow_p)
13840 strict_overflow_p));
13841 }
13843 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
13844 both unsigned and their total bits is shorter than the result. */
13848 {
13855 }
13861 strict_overflow_p)
13863 strict_overflow_p));
13874 strict_overflow_p)
13876 strict_overflow_p));
13883 strict_overflow_p);
13886 }
13888 /* We don't know sign of `t', so be conservative and return false. */
13890 }
13892 /* Return true if T is known to be non-negative. If the return
13893 value is based on the assumption that signed overflow is undefined,
13894 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13895 *STRICT_OVERFLOW_P. */
13897 static bool
13899 {
13904 {
13906 /* Query VRP to see if it has recorded any information about
13907 the range of this object. */
13921 strict_overflow_p)
13923 strict_overflow_p));
13927 }
13928 /* We don't know sign of `t', so be conservative and return false. */
13930 }
13932 /* Return true if T is known to be non-negative. If the return
13933 value is based on the assumption that signed overflow is undefined,
13934 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13935 *STRICT_OVERFLOW_P. */
13937 static bool
13939 {
13945 {
13947 {
13951 /* If the initializer is non-void, then it's a normal expression
13952 that will be assigned to the slot. */
13956 /* Otherwise, the initializer sets the slot in some way. One common
13957 way is an assignment statement at the end of the initializer. */
13959 {
13967 else
13969 }
13974 strict_overflow_p);
13977 }
13980 {
13984 {
14002 /* Always true. */
14006 /* sqrt(-0.0) is -0.0. */
14010 strict_overflow_p);
14043 /* True if the 1st argument is nonnegative. */
14045 strict_overflow_p);
14048 /* True if the 1st OR 2nd arguments are nonnegative. */
14050 strict_overflow_p)
14052 strict_overflow_p)));
14055 /* True if the 1st AND 2nd arguments are nonnegative. */
14057 strict_overflow_p)
14059 strict_overflow_p)));
14062 /* True if the 2nd argument is nonnegative. */
14064 strict_overflow_p);
14067 /* True if the 1st argument is nonnegative or the second
14068 argument is an even integer. */
14070 {
14074 }
14076 strict_overflow_p);
14079 /* True if the 1st argument is nonnegative or the second
14080 argument is an even integer valued real. */
14082 {
14083 REAL_VALUE_TYPE c;
14084 HOST_WIDE_INT n;
14089 {
14090 REAL_VALUE_TYPE cint;
14095 }
14096 }
14098 strict_overflow_p);
14102 }
14105 }
14112 strict_overflow_p);
14115 strict_overflow_p);
14118 strict_overflow_p);
14123 }
14125 /* We don't know sign of `t', so be conservative and return false. */
14127 }
14129 /* Return true if T is known to be non-negative. If the return
14130 value is based on the assumption that signed overflow is undefined,
14131 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14132 *STRICT_OVERFLOW_P. */
14134 bool
14136 {
14143 {
14150 strict_overflow_p);
14156 strict_overflow_p);
14165 }
14168 {
14176 strict_overflow_p);
14181 strict_overflow_p);
14196 }
14197 }
14199 /* Return true if `t' is known to be non-negative. Handle warnings
14200 about undefined signed overflow. */
14202 bool
14204 {
14211 "determining that expression is always "
14213 WARN_STRICT_OVERFLOW_MISC);
14215 }
14218 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14219 For floating point we further ensure that T is not denormal.
14220 Similar logic is present in nonzero_address in rtlanal.h.
14222 If the return value is based on the assumption that signed overflow
14223 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14224 change *STRICT_OVERFLOW_P. */
14226 static bool
14229 {
14231 {
14234 strict_overflow_p);
14237 {
14243 strict_overflow_p));
14244 }
14249 strict_overflow_p);
14253 }
14256 }
14258 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14259 For floating point we further ensure that T is not denormal.
14260 Similar logic is present in nonzero_address in rtlanal.h.
14262 If the return value is based on the assumption that signed overflow
14263 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14264 change *STRICT_OVERFLOW_P. */
14266 static bool
14268 tree type,
14269 tree op0,
14271 {
14274 {
14278 {
14279 /* With the presence of negative values it is hard
14280 to say something. */
14287 /* One of operands must be positive and the other non-negative. */
14288 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14289 overflows, on a twos-complement machine the sum of two
14290 nonnegative numbers can never be zero. */
14292 strict_overflow_p)
14294 strict_overflow_p));
14295 }
14300 {
14302 strict_overflow_p)
14304 strict_overflow_p))
14305 {
14308 }
14309 }
14318 {
14321 }
14328 {
14332 /* When both operands are nonzero, then MAX must be too. */
14334 strict_overflow_p))
14337 /* MAX where operand 0 is positive is positive. */
14339 strict_overflow_p);
14340 }
14341 /* MAX where operand 1 is positive is positive. */
14346 {
14350 }
14355 strict_overflow_p)
14357 strict_overflow_p));
14361 }
14364 }
14366 /* Return true when T is an address and is known to be nonzero.
14367 For floating point we further ensure that T is not denormal.
14368 Similar logic is present in nonzero_address in rtlanal.h.
14370 If the return value is based on the assumption that signed overflow
14371 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14372 change *STRICT_OVERFLOW_P. */
14374 static bool
14376 {
14379 {
14381 /* Query VRP to see if it has recorded any information about
14382 the range of this object. */
14389 {
14395 /* Weak declarations may link to NULL. */
14399 /* Constants are never weak. */
14404 }
14412 {
14416 }
14421 }
14423 }
14425 /* Return true when T is an address and is known to be nonzero.
14426 For floating point we further ensure that T is not denormal.
14427 Similar logic is present in nonzero_address in rtlanal.h.
14429 If the return value is based on the assumption that signed overflow
14430 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14431 change *STRICT_OVERFLOW_P. */
14433 bool
14435 {
14439 /* Doing something useful for floating point would need more work. */
14445 {
14448 strict_overflow_p);
14454 strict_overflow_p);
14462 }
14465 {
14468 strict_overflow_p);
14476 strict_overflow_p);
14494 strict_overflow_p);
14498 strict_overflow_p);
14505 }
14507 }
14509 /* Return true when T is an address and is known to be nonzero.
14510 Handle warnings about undefined signed overflow. */
14512 bool
14514 {
14521 "determining that expression is always "
14523 WARN_STRICT_OVERFLOW_MISC);
14525 }
14527 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14528 attempt to fold the expression to a constant without modifying TYPE,
14529 OP0 or OP1.
14531 If the expression could be simplified to a constant, then return
14532 the constant. If the expression would not be simplified to a
14533 constant, then return NULL_TREE. */
14535 tree
14537 {
14540 }
14542 /* Given the components of a unary expression CODE, TYPE and OP0,
14543 attempt to fold the expression to a constant without modifying
14544 TYPE or OP0.
14546 If the expression could be simplified to a constant, then return
14547 the constant. If the expression would not be simplified to a
14548 constant, then return NULL_TREE. */
14550 tree
14552 {
14555 }
14557 /* If EXP represents referencing an element in a constant string
14558 (either via pointer arithmetic or array indexing), return the
14559 tree representing the value accessed, otherwise return NULL. */
14561 tree
14563 {
14567 {
14569 tree index;
14570 tree string;
14574 else
14575 {
14579 /* Optimize the special-case of a zero lower bound.
14581 We convert the low_bound to sizetype to avoid some problems
14582 with constant folding. (E.g. suppose the lower bound is 1,
14583 and its mode is QI. Without the conversion,l (ARRAY
14584 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14585 +INDEX), which becomes (ARRAY+255+INDEX). Opps!) */
14590 }
14603 }
14605 }
14607 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14608 an integer constant, real, or fixed-point constant.
14610 TYPE is the type of the result. */
14612 static tree
14614 {
14618 {
14620 {
14622 HOST_WIDE_INT high;
14630 }
14637 {
14638 FIXED_VALUE_TYPE f;
14643 /* Propagate overflow flags. */
14645 {
14648 }
14652 }
14656 }
14659 }
14661 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14662 an integer constant or real constant.
14664 TYPE is the type of the result. */
14666 tree
14668 {
14672 {
14674 /* If the value is unsigned, then the absolute value is
14675 the same as the ordinary value. */
14678 /* Similarly, if the value is non-negative. */
14681 /* If the value is negative, then the absolute value is
14682 its negation. */
14683 else
14684 {
14686 HOST_WIDE_INT high;
14692 }
14698 else
14704 }
14707 }
14709 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14710 constant. TYPE is the type of the result. */
14712 static tree
14714 {
14724 }
14726 /* Given CODE, a relational operator, the target type, TYPE and two
14727 constant operands OP0 and OP1, return the result of the
14728 relational operation. If the result is not a compile time
14729 constant, then return NULL_TREE. */
14731 static tree
14733 {
14736 /* From here on, the only cases we handle are when the result is
14737 known to be a constant. */
14740 {
14744 /* Handle the cases where either operand is a NaN. */
14746 {
14748 {
14776 }
14779 }
14782 }
14785 {
14789 }
14791 /* Handle equality/inequality of complex constants. */
14793 {
14804 else
14806 }
14808 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14810 To compute GT, swap the arguments and do LT.
14811 To compute GE, do LT and invert the result.
14812 To compute LE, swap the arguments, do LT and invert the result.
14813 To compute NE, do EQ and invert the result.
14815 Therefore, the code below must handle only EQ and LT. */
14818 {
14823 }
14825 /* Note that it is safe to invert for real values here because we
14826 have already handled the one case that it matters. */
14830 {
14833 }
14835 /* Compute a result for LT or EQ if args permit;
14836 Otherwise return T. */
14838 {
14843 else
14845 }
14846 else
14852 }
14854 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14855 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14856 itself. */
14858 tree
14860 {
14861 /* If the expression does not have side effects then we don't have to wrap
14862 it with a cleanup point expression. */
14866 /* If the expression is a return, check to see if the expression inside the
14867 return has no side effects or the right hand side of the modify expression
14868 inside the return. If either don't have side effects set we don't need to
14869 wrap the expression in a cleanup point expression. Note we don't check the
14870 left hand side of the modify because it should always be a return decl. */
14872 {
14879 }
14882 }
14884 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14885 of an indirection through OP0, or NULL_TREE if no simplification is
14886 possible. */
14888 tree
14890 {
14892 tree subtype;
14900 {
14903 /* *&CONST_DECL -> to the value of the const decl. */
14906 /* *&p => p; make sure to handle *&"str"[cst] here. */
14908 {
14912 else
14914 }
14915 /* *(foo *)&fooarray => fooarray[0] */
14918 {
14924 }
14925 /* *(foo *)&complexfoo => __real__ complexfoo */
14929 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14932 {
14936 }
14937 }
14939 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14942 {
14945 tree op00type;
14952 {
14956 }
14957 }
14959 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14962 {
14963 tree type_domain;
14970 }
14973 }
14975 /* Builds an expression for an indirection through T, simplifying some
14976 cases. */
14978 tree
14980 {
14986 else
14988 }
14990 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14992 tree
14994 {
14999 else
15001 }
15003 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15004 whose result is ignored. The type of the returned tree need not be
15005 the same as the original expression. */
15007 tree
15009 {
15015 {
15026 else
15032 {
15048 }
15053 }
15054 }
15056 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15057 This can only be applied to objects of a sizetype. */
15059 tree
15061 {
15068 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15069 have to do anything. Only do this when we are not given a const,
15070 because in that case, this check is more expensive than just
15071 doing it. */
15073 {
15078 }
15080 /* If divisor is a power of two, simplify this to bit manipulation. */
15082 {
15084 {
15097 {
15098 high++;
15101 }
15105 }
15106 else
15107 {
15108 tree t;
15114 }
15115 }
15116 else
15117 {
15122 }
15125 }
15127 /* Likewise, but round down. */
15129 tree
15131 {
15138 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15139 have to do anything. Only do this when we are not given a const,
15140 because in that case, this check is more expensive than just
15141 doing it. */
15143 {
15148 }
15150 /* If divisor is a power of two, simplify this to bit manipulation. */
15152 {
15153 tree t;
15157 }
15158 else
15159 {
15164 }
15167 }
15169 /* Returns the pointer to the base of the object addressed by EXP and
15170 extracts the information about the offset of the access, storing it
15171 to PBITPOS and POFFSET. */
15173 static tree
15176 {
15177 tree core;
15180 HOST_WIDE_INT bitsize;
15183 {
15188 }
15189 else
15190 {
15194 }
15197 }
15199 /* Returns true if addresses of E1 and E2 differ by a constant, false
15200 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15202 bool
15204 {
15218 {
15228 }
15230 {
15231 /* If only one of the offsets is non-constant, the difference cannot
15232 be a constant. */
15234 }
15235 else
15240 }
15242 /* Simplify the floating point expression EXP when the sign of the
15243 result is not significant. Return NULL_TREE if no simplification
15244 is possible. */
15246 tree
15248 {
15252 {
15287 {
15290 {
15292 /* Strip copysign function call, return the 1st argument. */
15298 /* Strip sign ops from the argument of "odd" math functions. */
15300 {
15304 }
15306 }
15307 }
15312 }
15314 }