| blob | 5af6f0d686af2dcc0b701c44cd54957c077a9efa |
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 };
126 tree);
147 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
148 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
149 and SUM1. Then this yields nonzero if overflow occurred during the
150 addition.
152 Overflow occurs if A and B have the same sign, but A and SUM differ in
153 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
154 sign. */
155 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
156 \f
157 /* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
158 We do that by representing the two-word integer in 4 words, with only
159 HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
160 number. The value of the word is LOWPART + HIGHPART * BASE. */
162 #define LOWPART(x) \
163 ((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
164 #define HIGHPART(x) \
165 ((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
166 #define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
168 /* Unpack a two-word integer into 4 words.
169 LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
170 WORDS points to the array of HOST_WIDE_INTs. */
172 static void
174 {
179 }
181 /* Pack an array of 4 words into a two-word integer.
182 WORDS points to the array of words.
183 The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
185 static void
188 {
191 }
192 \f
193 /* Force the double-word integer L1, H1 to be within the range of the
194 integer type TYPE. Stores the properly truncated and sign-extended
195 double-word integer in *LV, *HV. Returns true if the operation
196 overflows, that is, argument and result are different. */
198 int
201 {
210 else
213 /* Size types *are* sign extended. */
218 /* First clear all bits that are beyond the type's precision. */
220 ;
223 else
224 {
228 }
230 /* Then do sign extension if necessary. */
236 {
237 /* Sign extend top half? */
241 }
243 {
246 }
247 else
248 {
249 /* Sign extend bottom half? */
251 {
254 }
255 }
260 /* If the value didn't fit, signal overflow. */
262 }
264 /* We force the double-int HIGH:LOW to the range of the type TYPE by
265 sign or zero extending it.
266 OVERFLOWABLE indicates if we are interested
267 in overflow of the value, when >0 we are only interested in signed
268 overflow, for <0 we are interested in any overflow. OVERFLOWED
269 indicates whether overflow has already occurred. CONST_OVERFLOWED
270 indicates whether constant overflow has already occurred. We force
271 T's value to be within range of T's type (by setting to 0 or 1 all
272 the bits outside the type's range). We set TREE_OVERFLOWED if,
273 OVERFLOWED is nonzero,
274 or OVERFLOWABLE is >0 and signed overflow occurs
275 or OVERFLOWABLE is <0 and any overflow occurs
276 We return a new tree node for the extended double-int. The node
277 is shared if no overflow flags are set. */
279 tree
283 {
287 /* Size types *are* sign extended. */
294 /* If we need to set overflow flags, return a new unshared node. */
296 {
300 {
307 }
308 }
310 /* Else build a shared node. */
312 }
313 \f
314 /* Add two doubleword integers with doubleword result.
315 Return nonzero if the operation overflows according to UNSIGNED_P.
316 Each argument is given as two `HOST_WIDE_INT' pieces.
317 One argument is L1 and H1; the other, L2 and H2.
318 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
320 int
325 {
327 HOST_WIDE_INT h;
337 else
339 }
341 /* Negate a doubleword integer with doubleword result.
342 Return nonzero if the operation overflows, assuming it's signed.
343 The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
344 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
346 int
349 {
351 {
355 }
356 else
357 {
361 }
362 }
363 \f
364 /* Multiply two doubleword integers with doubleword result.
365 Return nonzero if the operation overflows according to UNSIGNED_P.
366 Each argument is given as two `HOST_WIDE_INT' pieces.
367 One argument is L1 and H1; the other, L2 and H2.
368 The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
370 int
375 {
390 {
393 {
395 /* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
397 /* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
401 }
403 }
408 /* Unsigned overflow is immediate. */
412 /* Check for signed overflow by calculating the signed representation of the
413 top half of the result; it should agree with the low half's sign bit. */
415 {
418 }
420 {
423 }
425 }
426 \f
427 /* Shift the doubleword integer in L1, H1 left by COUNT places
428 keeping only PREC bits of result.
429 Shift right if COUNT is negative.
430 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
431 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
433 void
437 {
441 {
444 }
450 {
451 /* Shifting by the host word size is undefined according to the
452 ANSI standard, so we must handle this as a special case. */
455 }
457 {
460 }
461 else
462 {
466 }
468 /* Sign extend all bits that are beyond the precision. */
476 ;
478 {
481 }
482 else
483 {
487 }
488 }
490 /* Shift the doubleword integer in L1, H1 right by COUNT places
491 keeping only PREC bits of result. COUNT must be positive.
492 ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
493 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
495 void
500 {
503 signmask = (arith
511 {
512 /* Shifting by the host word size is undefined according to the
513 ANSI standard, so we must handle this as a special case. */
516 }
518 {
521 }
522 else
523 {
527 }
529 /* Zero / sign extend all bits that are beyond the precision. */
532 {
535 }
537 ;
539 {
542 }
543 else
544 {
548 }
549 }
550 \f
551 /* Rotate the doubleword integer in L1, H1 left by COUNT places
552 keeping only PREC bits of result.
553 Rotate right if COUNT is negative.
554 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
556 void
560 {
572 }
574 /* Rotate the doubleword integer in L1, H1 left by COUNT places
575 keeping only PREC bits of result. COUNT must be positive.
576 Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
578 void
582 {
594 }
595 \f
596 /* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
597 for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
598 CODE is a tree code for a kind of division, one of
599 TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
600 or EXACT_DIV_EXPR
601 It controls how the quotient is rounded to an integer.
602 Return nonzero if the operation overflows.
603 UNS nonzero says do unsigned division. */
605 int
608 HOST_WIDE_INT hnum_orig,
610 HOST_WIDE_INT hden_orig,
614 {
630 /* Calculate quotient sign and convert operands to unsigned. */
632 {
634 {
636 /* (minimum integer) / (-1) is the only overflow case. */
640 }
642 {
645 }
646 }
651 /* This unsigned division rounds toward zero. */
654 }
658 /* hden != 0 already checked. */
663 }
673 /* Special code for when the divisor < BASE. */
675 {
676 /* hnum != 0 already checked. */
678 {
682 }
683 }
684 else
685 {
686 /* Full double precision division,
687 with thanks to Don Knuth's "Seminumerical Algorithms". */
691 /* Find the highest nonzero divisor digit. */
694 {
697 }
699 /* Insure that the first digit of the divisor is at least BASE/2.
700 This is required by the quotient digit estimation algorithm. */
707 {
711 }
716 {
721 }
722 }
726 /* Main loop */
728 {
729 /* Guess the next quotient digit, quo_est, by dividing the first
730 two remaining dividend digits by the high order quotient digit.
731 quo_est is never low and is at most 2 high. */
738 else
741 /* Refine quo_est so it's usually correct, and at most one high. */
746 quo_est--;
748 /* Try QUO_EST as the quotient digit, by multiplying the
749 divisor by QUO_EST and subtracting from the remaining dividend.
750 Keep in mind that QUO_EST is the I - 1st digit. */
754 {
760 }
762 /* If quo_est was high by one, then num[i] went negative and
763 we need to correct things. */
765 {
766 quo_est--;
769 {
773 }
776 }
778 /* Store the quotient digit. */
780 }
781 }
785 finish_up:
786 /* If result is negative, make it so. */
790 /* Compute trial remainder: rem = num - (quo * den) */
796 {
805 {
806 /* quo = quo - 1; */
809 }
810 else
817 {
820 }
821 else
827 {
833 /* Get absolute values. */
839 /* If (2 * abs (lrem) >= abs (lden)) */
848 {
850 /* quo = quo - 1; */
853 else
854 /* quo = quo + 1; */
857 }
858 else
860 }
865 }
867 /* Compute true remainder: rem = num - (quo * den) */
872 }
874 /* If ARG2 divides ARG1 with zero remainder, carries out the division
875 of type CODE and returns the quotient.
876 Otherwise returns NULL_TREE. */
878 static tree
880 {
890 /* &obj[0] + -128 really should be compiled as &obj[-8] rather than
891 &obj[some_exotic_number]. */
893 {
897 type);
898 }
899 else
910 }
911 \f
912 /* This is nonzero if we should defer warnings about undefined
913 overflow. This facility exists because these warnings are a
914 special case. The code to estimate loop iterations does not want
915 to issue any warnings, since it works with expressions which do not
916 occur in user code. Various bits of cleanup code call fold(), but
917 only use the result if it has certain characteristics (e.g., is a
918 constant); that code only wants to issue a warning if the result is
919 used. */
923 /* If a warning about undefined overflow is deferred, this is the
924 warning. Note that this may cause us to turn two warnings into
925 one, but that is fine since it is sufficient to only give one
926 warning per expression. */
930 /* If a warning about undefined overflow is deferred, this is the
931 level at which the warning should be emitted. */
935 /* Start deferring overflow warnings. We could use a stack here to
936 permit nested calls, but at present it is not necessary. */
938 void
940 {
942 }
944 /* Stop deferring overflow warnings. If there is a pending warning,
945 and ISSUE is true, then issue the warning if appropriate. STMT is
946 the statement with which the warning should be associated (used for
947 location information); STMT may be NULL. CODE is the level of the
948 warning--a warn_strict_overflow_code value. This function will use
949 the smaller of CODE and the deferred code when deciding whether to
950 issue the warning. CODE may be zero to mean to always use the
951 deferred code. */
953 void
955 {
957 location_t locus;
962 {
968 }
979 /* Use the smallest code level when deciding to issue the
980 warning. */
989 else
992 }
994 /* Stop deferring overflow warnings, ignoring any deferred
995 warnings. */
997 void
999 {
1001 }
1003 /* Whether we are deferring overflow warnings. */
1005 bool
1007 {
1009 }
1011 /* This is called when we fold something based on the fact that signed
1012 overflow is undefined. */
1014 static void
1016 {
1019 {
1022 {
1025 }
1026 }
1029 }
1030 \f
1031 /* Return true if the built-in mathematical function specified by CODE
1032 is odd, i.e. -f(x) == f(-x). */
1034 static bool
1036 {
1038 {
1072 }
1074 }
1076 /* Check whether we may negate an integer constant T without causing
1077 overflow. */
1079 bool
1081 {
1084 tree type;
1094 {
1099 }
1100 else
1105 }
1107 /* Determine whether an expression T can be cheaply negated using
1108 the function negate_expr without introducing undefined overflow. */
1110 static bool
1112 {
1113 tree type;
1122 {
1127 /* Check that -CST will not overflow type. */
1153 /* -(A + B) -> (-B) - A. */
1158 /* -(A + B) -> (-A) - B. */
1162 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
1172 /* Fall through. */
1185 /* In general we can't negate A / B, because if A is INT_MIN and
1186 B is 1, we may turn this into INT_MIN / -1 which is undefined
1187 and actually traps on some architectures. But if overflow is
1188 undefined, we can negate, because - (INT_MIN / 1) is an
1189 overflow. */
1197 /* Negate -((double)float) as (double)(-float). */
1199 {
1203 }
1207 /* Negate -f(x) as f(-x). */
1213 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1215 {
1221 }
1226 }
1228 }
1230 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
1231 simplification is possible.
1232 If negate_expr_p would return true for T, NULL_TREE will never be
1233 returned. */
1235 static tree
1237 {
1239 tree tem;
1242 {
1243 /* Convert - (~A) to A + 1. */
1259 /* Two's complement FP formats, such as c4x, may overflow. */
1269 {
1278 }
1300 {
1301 /* -(A + B) -> (-B) - A. */
1305 {
1309 }
1311 /* -(A + B) -> (-A) - B. */
1313 {
1317 }
1318 }
1322 /* - (A - B) -> B - A */
1334 /* Fall through. */
1338 {
1347 }
1355 /* In general we can't negate A / B, because if A is INT_MIN and
1356 B is 1, we may turn this into INT_MIN / -1 which is undefined
1357 and actually traps on some architectures. But if overflow is
1358 undefined, we can negate, because - (INT_MIN / 1) is an
1359 overflow. */
1361 {
1366 {
1373 }
1376 {
1383 }
1384 }
1388 /* Convert -((double)float) into (double)(-float). */
1390 {
1394 }
1398 /* Negate -f(x) as f(-x). */
1401 {
1407 }
1411 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
1413 {
1418 {
1425 }
1426 }
1431 }
1434 }
1436 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
1437 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
1438 return NULL_TREE. */
1440 static tree
1442 {
1455 }
1456 \f
1457 /* Split a tree IN into a constant, literal and variable parts that could be
1458 combined with CODE to make IN. "constant" means an expression with
1459 TREE_CONSTANT but that isn't an actual constant. CODE must be a
1460 commutative arithmetic operation. Store the constant part into *CONP,
1461 the literal in *LITP and return the variable part. If a part isn't
1462 present, set it to null. If the tree does not decompose in this way,
1463 return the entire tree as the variable part and the other parts as null.
1465 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
1466 case, we negate an operand that was subtracted. Except if it is a
1467 literal for which we use *MINUS_LITP instead.
1469 If NEGATE_P is true, we are negating all of IN, again except a literal
1470 for which we use *MINUS_LITP instead.
1472 If IN is itself a literal or constant, return it as appropriate.
1474 Note that we do not guarantee that any of the three values will be the
1475 same type as IN, but they will have the same signedness and mode. */
1477 static tree
1480 {
1487 /* Strip any conversions that don't change the machine mode or signedness. */
1496 /* We can associate addition and subtraction together (even
1497 though the C standard doesn't say so) for integers because
1498 the value is not affected. For reals, the value might be
1499 affected, so we can't. */
1502 {
1508 /* First see if either of the operands is a literal, then a constant. */
1521 /* If we haven't dealt with either operand, this is not a case we can
1522 decompose. Otherwise, VAR is either of the ones remaining, if any. */
1527 else
1530 /* Now do any needed negations. */
1537 }
1540 else
1544 {
1551 }
1554 }
1556 /* Re-associate trees split by the above function. T1 and T2 are either
1557 expressions to associate or null. Return the new expression, if any. If
1558 we build an operation, do it in TYPE and with CODE. */
1560 static tree
1562 {
1568 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
1569 try to fold this since we will have infinite recursion. But do
1570 deal with any NEGATE_EXPRs. */
1573 {
1575 {
1584 }
1586 {
1589 }
1593 }
1597 }
1598 \f
1599 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1600 for use in int_const_binop, size_binop and size_diffop. */
1602 static bool
1604 {
1611 {
1620 }
1625 }
1628 /* Combine two integer constants ARG1 and ARG2 under operation CODE
1629 to produce a new constant. Return NULL_TREE if we don't know how
1630 to evaluate CODE at compile-time.
1632 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1634 tree
1636 {
1640 HOST_WIDE_INT hi;
1642 HOST_WIDE_INT garbageh;
1643 tree t;
1646 int is_sizetype
1656 {
1672 /* It's unclear from the C standard whether shifts can overflow.
1673 The following code ignores overflow; perhaps a C standard
1674 interpretation ruling is needed. */
1703 /* This is a shortcut for a common special case. */
1708 {
1714 }
1716 /* ... fall through ... */
1722 {
1725 }
1728 {
1731 }
1738 /* This is a shortcut for a common special case. */
1743 {
1748 }
1750 /* ... fall through ... */
1768 else
1774 else
1780 }
1783 {
1786 /* Propagate overflow flags ourselves. */
1789 {
1792 }
1793 }
1794 else
1800 }
1802 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1803 constant. We assume ARG1 and ARG2 have the same data type, or at least
1804 are the same kind of constant and the same machine mode. Return zero if
1805 combining the constants is not allowed in the current operating mode.
1807 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1809 static tree
1811 {
1812 /* Sanity check for the recursive cases. */
1823 {
1825 REAL_VALUE_TYPE d1;
1826 REAL_VALUE_TYPE d2;
1827 REAL_VALUE_TYPE value;
1828 REAL_VALUE_TYPE result;
1832 /* The following codes are handled by real_arithmetic. */
1834 {
1845 }
1853 /* Don't perform operation if we honor signaling NaNs and
1854 either operand is a NaN. */
1859 /* Don't perform operation if it would raise a division
1860 by zero exception. */
1866 /* If either operand is a NaN, just return it. Otherwise, set up
1867 for floating-point trap; we return an overflow. */
1876 /* Don't constant fold this floating point operation if
1877 the result has overflowed and flag_trapping_math. */
1885 /* Don't constant fold this floating point operation if the
1886 result may dependent upon the run-time rounding mode and
1887 flag_rounding_math is set, or if GCC's software emulation
1888 is unable to accurately represent the result. */
1899 }
1902 {
1903 FIXED_VALUE_TYPE f1;
1904 FIXED_VALUE_TYPE f2;
1905 FIXED_VALUE_TYPE result;
1910 /* The following codes are handled by fixed_arithmetic. */
1912 {
1929 }
1936 /* Propagate overflow flags. */
1938 {
1941 }
1945 }
1948 {
1957 {
1968 notrunc);
1972 notrunc);
1976 {
1977 tree magsquared
1981 notrunc);
1982 tree t1
1986 notrunc);
1987 tree t2
1991 notrunc);
1998 }
2003 }
2007 }
2010 }
2012 /* Create a size type INT_CST node with NUMBER sign extended. KIND
2013 indicates which particular sizetype to create. */
2015 tree
2017 {
2019 }
2020 \f
2021 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2022 is a tree code. The type of the result is taken from the operands.
2023 Both must be equivalent integer types, ala int_binop_types_match_p.
2024 If the operands are constant, so is the result. */
2026 tree
2028 {
2037 /* Handle the special case of two integer constants faster. */
2039 {
2040 /* And some specific cases even faster than that. */
2042 {
2047 }
2049 {
2052 }
2054 {
2057 }
2059 /* Handle general case of two integer constants. */
2061 }
2064 }
2066 /* Given two values, either both of sizetype or both of bitsizetype,
2067 compute the difference between the two values. Return the value
2068 in signed type corresponding to the type of the operands. */
2070 tree
2072 {
2074 tree ctype;
2079 /* If the type is already signed, just do the simple thing. */
2087 else
2090 /* If either operand is not a constant, do the conversions to the signed
2091 type and subtract. The hardware will do the right thing with any
2092 overflow in the subtraction. */
2097 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2098 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2099 overflow) and negate (which can't either). Special-case a result
2100 of zero while we're here. */
2105 else
2109 }
2110 \f
2111 /* A subroutine of fold_convert_const handling conversions of an
2112 INTEGER_CST to another integer type. */
2114 static tree
2116 {
2117 tree t;
2119 /* Given an integer constant, make new constant with new type,
2120 appropriately sign-extended or truncated. */
2123 /* Don't set the overflow when
2124 converting from a pointer, */
2126 /* or to a sizetype with same signedness
2127 and the precision is unchanged.
2128 ??? sizetype is always sign-extended,
2129 but its signedness depends on the
2130 frontend. Thus we see spurious overflows
2131 here if we do not check this. */
2146 }
2148 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2149 to an integer type. */
2151 static tree
2153 {
2155 tree t;
2157 /* The following code implements the floating point to integer
2158 conversion rules required by the Java Language Specification,
2159 that IEEE NaNs are mapped to zero and values that overflow
2160 the target precision saturate, i.e. values greater than
2161 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2162 are mapped to INT_MIN. These semantics are allowed by the
2163 C and C++ standards that simply state that the behavior of
2164 FP-to-integer conversion is unspecified upon overflow. */
2167 REAL_VALUE_TYPE r;
2171 {
2178 }
2180 /* If R is NaN, return zero and show we have an overflow. */
2182 {
2186 }
2188 /* See if R is less than the lower bound or greater than the
2189 upper bound. */
2192 {
2196 {
2200 }
2201 }
2204 {
2207 {
2210 {
2214 }
2215 }
2216 }
2224 }
2226 /* A subroutine of fold_convert_const handling conversions of a
2227 FIXED_CST to an integer type. */
2229 static tree
2231 {
2232 tree t;
2236 /* Right shift FIXED_CST to temp by fbit. */
2240 {
2245 /* Left shift temp to temp_trunc by fbit. */
2250 }
2251 else
2252 {
2257 }
2259 /* If FIXED_CST is negative, we need to round the value toward 0.
2260 By checking if the fractional bits are not zero to add 1 to temp. */
2263 {
2264 double_int one;
2268 }
2270 /* Given a fixed-point constant, make new constant with new type,
2271 appropriately sign-extended or truncated. */
2279 }
2281 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2282 to another floating point type. */
2284 static tree
2286 {
2287 REAL_VALUE_TYPE value;
2288 tree t;
2295 }
2297 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2298 to a floating point type. */
2300 static tree
2302 {
2303 REAL_VALUE_TYPE value;
2304 tree t;
2313 }
2315 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2316 to another fixed-point type. */
2318 static tree
2320 {
2321 FIXED_VALUE_TYPE value;
2322 tree t;
2329 /* Propagate overflow flags. */
2331 {
2334 }
2338 }
2340 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2341 to a fixed-point type. */
2343 static tree
2345 {
2346 FIXED_VALUE_TYPE value;
2347 tree t;
2356 /* Propagate overflow flags. */
2358 {
2361 }
2365 }
2367 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2368 to a fixed-point type. */
2370 static tree
2372 {
2373 FIXED_VALUE_TYPE value;
2374 tree t;
2382 /* Propagate overflow flags. */
2384 {
2387 }
2391 }
2393 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2394 type TYPE. If no simplification can be done return NULL_TREE. */
2396 static tree
2398 {
2403 {
2410 }
2412 {
2419 }
2421 {
2428 }
2430 }
2432 /* Construct a vector of zero elements of vector type TYPE. */
2434 static tree
2436 {
2447 }
2449 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2451 bool
2453 {
2468 {
2487 }
2488 }
2490 /* Convert expression ARG to type TYPE. Used by the middle-end for
2491 simple conversions in preference to calling the front-end's convert. */
2493 tree
2495 {
2497 tree tem;
2511 {
2516 {
2520 }
2525 {
2528 }
2535 {
2539 }
2541 {
2545 }
2547 {
2551 }
2554 {
2572 }
2577 {
2581 }
2584 {
2598 }
2602 {
2612 {
2616 {
2620 }
2628 }
2632 }
2650 }
2651 }
2652 \f
2653 /* Return false if expr can be assumed not to be an lvalue, true
2654 otherwise. */
2656 static bool
2658 {
2659 /* We only need to wrap lvalue tree codes. */
2661 {
2696 /* Assume the worst for front-end tree codes. */
2700 }
2703 }
2705 /* Return an expr equal to X but certainly not valid as an lvalue. */
2707 tree
2709 {
2710 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2711 us. */
2718 }
2720 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2721 Zero means allow extended lvalues. */
2725 /* When pedantic, return an expr equal to X but certainly not valid as a
2726 pedantic lvalue. Otherwise, return X. */
2728 static tree
2730 {
2733 else
2735 }
2736 \f
2737 /* Given a tree comparison code, return the code that is the logical inverse
2738 of the given code. It is not safe to do this for floating-point
2739 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2740 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2742 enum tree_code
2744 {
2749 {
2780 }
2781 }
2783 /* Similar, but return the comparison that results if the operands are
2784 swapped. This is safe for floating-point. */
2786 enum tree_code
2788 {
2790 {
2816 }
2817 }
2820 /* Convert a comparison tree code from an enum tree_code representation
2821 into a compcode bit-based encoding. This function is the inverse of
2822 compcode_to_comparison. */
2824 static enum comparison_code
2826 {
2828 {
2859 }
2860 }
2862 /* Convert a compcode bit-based encoding of a comparison operator back
2863 to GCC's enum tree_code representation. This function is the
2864 inverse of comparison_to_compcode. */
2866 static enum tree_code
2868 {
2870 {
2901 }
2902 }
2904 /* Return a tree for the comparison which is the combination of
2905 doing the AND or OR (depending on CODE) of the two operations LCODE
2906 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2907 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2908 if this makes the transformation invalid. */
2910 tree
2914 {
2921 {
2932 }
2935 {
2936 /* Eliminate unordered comparisons, as well as LTGT and ORD
2937 which are not used unless the mode has NaNs. */
2943 }
2945 {
2946 /* Check that the original operation and the optimized ones will trap
2947 under the same condition. */
2958 /* In a short-circuited boolean expression the LHS might be
2959 such that the RHS, if evaluated, will never trap. For
2960 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2961 if neither x nor y is NaN. (This is a mixed blessing: for
2962 example, the expression above will never trap, hence
2963 optimizing it to x < y would be invalid). */
2968 /* If the comparison was short-circuited, and only the RHS
2969 trapped, we may now generate a spurious trap. */
2974 /* If we changed the conditions that cause a trap, we lose. */
2977 }
2983 else
2986 }
2988 /* Return nonzero if CODE is a tree code that represents a truth value. */
2990 static int
2992 {
2997 }
2998 \f
2999 /* Return nonzero if two operands (typically of the same tree node)
3000 are necessarily equal. If either argument has side-effects this
3001 function returns zero. FLAGS modifies behavior as follows:
3003 If OEP_ONLY_CONST is set, only return nonzero for constants.
3004 This function tests whether the operands are indistinguishable;
3005 it does not test whether they are equal using C's == operation.
3006 The distinction is important for IEEE floating point, because
3007 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3008 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3010 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3011 even though it may hold multiple values during a function.
3012 This is because a GCC tree node guarantees that nothing else is
3013 executed between the evaluation of its "operands" (which may often
3014 be evaluated in arbitrary order). Hence if the operands themselves
3015 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3016 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3017 unset means assuming isochronic (or instantaneous) tree equivalence.
3018 Unless comparing arbitrary expression trees, such as from different
3019 statements, this flag can usually be left unset.
3021 If OEP_PURE_SAME is set, then pure functions with identical arguments
3022 are considered the same. It is used when the caller has other ways
3023 to ensure that global memory is unchanged in between. */
3025 int
3027 {
3028 /* If either is ERROR_MARK, they aren't equal. */
3032 /* If both types don't have the same signedness, then we can't consider
3033 them equal. We must check this before the STRIP_NOPS calls
3034 because they may change the signedness of the arguments. */
3038 /* If both types don't have the same precision, then it is not safe
3039 to strip NOPs. */
3046 /* In case both args are comparisons but with different comparison
3047 code, try to swap the comparison operands of one arg to produce
3048 a match and compare that variant. */
3052 {
3060 }
3063 /* This is needed for conversions and for COMPONENT_REF.
3064 Might as well play it safe and always test this. */
3070 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3071 We don't care about side effects in that case because the SAVE_EXPR
3072 takes care of that for us. In all other cases, two expressions are
3073 equal if they have no side effects. If we have two identical
3074 expressions with side effects that should be treated the same due
3075 to the only side effects being identical SAVE_EXPR's, that will
3076 be detected in the recursive calls below. */
3082 /* Next handle constant cases, those for which we can return 1 even
3083 if ONLY_CONST is set. */
3086 {
3101 {
3102 /* If we do not distinguish between signed and unsigned zero,
3103 consider them equal. */
3106 }
3110 {
3116 {
3118 flags))
3122 }
3125 }
3129 flags)
3131 flags));
3144 }
3149 /* Define macros to test an operand from arg0 and arg1 for equality and a
3150 variant that allows null and views null as being different from any
3151 non-null value. In the latter case, if either is null, the both
3152 must be; otherwise, do the normal comparison. */
3153 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3154 TREE_OPERAND (arg1, N), flags)
3156 #define OP_SAME_WITH_NULL(N) \
3157 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3158 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3161 {
3163 /* Two conversions are equal only if signedness and modes match. */
3165 {
3175 }
3185 /* For commutative ops, allow the other order. */
3193 /* If either of the pointer (or reference) expressions we are
3194 dereferencing contain a side effect, these cannot be equal. */
3200 {
3210 /* Operands 2 and 3 may be null.
3211 Compare the array index by value if it is constant first as we
3212 may have different types but same value here. */
3221 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3222 may be NULL when we're called to compare MEM_EXPRs. */
3232 }
3236 {
3251 /* Otherwise take into account this is a commutative operation. */
3259 }
3263 {
3265 /* If the CALL_EXPRs call different functions, then they
3266 clearly can not be equal. */
3268 flags))
3271 {
3275 else
3279 }
3281 /* Now see if all the arguments are the same. */
3282 {
3293 /* If we get here and both argument lists are exhausted
3294 then the CALL_EXPRs are equal. */
3296 }
3299 }
3302 /* Consider __builtin_sqrt equal to sqrt. */
3310 }
3312 #undef OP_SAME
3313 #undef OP_SAME_WITH_NULL
3314 }
3315 \f
3316 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3317 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3319 When in doubt, return 0. */
3321 static int
3323 {
3335 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3336 and see if the inner values are the same. This removes any
3337 signedness comparison, which doesn't matter here. */
3344 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3345 actual comparison operand, ARG0.
3347 First throw away any conversions to wider types
3348 already present in the operands. */
3357 {
3360 /* Make sure shorter operand is extended the right way
3361 to match the longer operand. */
3367 }
3370 }
3371 \f
3372 /* See if ARG is an expression that is either a comparison or is performing
3373 arithmetic on comparisons. The comparisons must only be comparing
3374 two different values, which will be stored in *CVAL1 and *CVAL2; if
3375 they are nonzero it means that some operands have already been found.
3376 No variables may be used anywhere else in the expression except in the
3377 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3378 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3380 If this is true, return 1. Otherwise, return zero. */
3382 static int
3384 {
3388 /* We can handle some of the tcc_expression cases here. */
3398 {
3399 /* If we've already found a CVAL1 or CVAL2, this expression is
3400 two complex to handle. */
3406 }
3409 {
3432 /* First see if we can handle the first operand, then the second. For
3433 the second operand, we know *CVAL1 can't be zero. It must be that
3434 one side of the comparison is each of the values; test for the
3435 case where this isn't true by failing if the two operands
3436 are the same. */
3445 ;
3449 ;
3450 else
3454 ;
3458 ;
3459 else
3466 }
3467 }
3468 \f
3469 /* ARG is a tree that is known to contain just arithmetic operations and
3470 comparisons. Evaluate the operations in the tree substituting NEW0 for
3471 any occurrence of OLD0 as an operand of a comparison and likewise for
3472 NEW1 and OLD1. */
3474 static tree
3476 {
3481 /* We can handle some of the tcc_expression cases here. */
3489 {
3504 {
3521 }
3522 /* Fall through - ??? */
3525 {
3529 /* We need to check both for exact equality and tree equality. The
3530 former will be true if the operand has a side-effect. In that
3531 case, we know the operand occurred exactly once. */
3544 }
3548 }
3549 }
3550 \f
3551 /* Return a tree for the case when the result of an expression is RESULT
3552 converted to TYPE and OMITTED was previously an operand of the expression
3553 but is now not needed (e.g., we folded OMITTED * 0).
3555 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3556 the conversion of RESULT to TYPE. */
3558 tree
3560 {
3563 /* If the resulting operand is an empty statement, just return the omitted
3564 statement casted to void. */
3572 }
3574 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3576 static tree
3578 {
3581 /* If the resulting operand is an empty statement, just return the omitted
3582 statement casted to void. */
3590 }
3592 /* Return a tree for the case when the result of an expression is RESULT
3593 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3594 of the expression but are now not needed.
3596 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3597 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3598 evaluated before OMITTED2. Otherwise, if neither has side effects,
3599 just do the conversion of RESULT to TYPE. */
3601 tree
3603 {
3612 }
3614 \f
3615 /* Return a simplified tree node for the truth-negation of ARG. This
3616 never alters ARG itself. We assume that ARG is an operation that
3617 returns a truth value (0 or 1).
3619 FIXME: one would think we would fold the result, but it causes
3620 problems with the dominator optimizer. */
3622 tree
3624 {
3628 /* If this is a comparison, we can simply invert it, except for
3629 floating-point non-equality comparisons, in which case we just
3630 enclose a TRUTH_NOT_EXPR around what we have. */
3633 {
3636 && flag_trapping_math
3640 else
3641 {
3646 else
3649 }
3650 }
3653 {
3668 /* Here we can invert either operand. We invert the first operand
3669 unless the second operand is a TRUTH_NOT_EXPR in which case our
3670 result is the XOR of the first operand with the inside of the
3671 negation of the second operand. */
3676 else
3695 {
3698 /* A COND_EXPR may have a throw as one operand, which
3699 then has void type. Just leave void operands
3700 as they are. */
3706 }
3739 }
3742 }
3744 /* Return a simplified tree node for the truth-negation of ARG. This
3745 never alters ARG itself. We assume that ARG is an operation that
3746 returns a truth value (0 or 1).
3748 FIXME: one would think we would fold the result, but it causes
3749 problems with the dominator optimizer. */
3751 tree
3753 {
3754 tree tem;
3764 }
3766 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3767 operands are another bit-wise operation with a common input. If so,
3768 distribute the bit operations to save an operation and possibly two if
3769 constants are involved. For example, convert
3770 (A | B) & (A | C) into A | (B & C)
3771 Further simplification will occur if B and C are constants.
3773 If this optimization cannot be done, 0 will be returned. */
3775 static tree
3777 {
3778 tree common;
3788 {
3792 }
3794 {
3798 }
3800 {
3804 }
3806 {
3810 }
3811 else
3816 }
3818 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3819 with code CODE. This optimization is unsafe. */
3820 static tree
3822 {
3826 /* (A / C) +- (B / C) -> (A +- B) / C. */
3836 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3841 {
3853 }
3856 }
3857 \f
3858 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3859 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3861 static tree
3864 {
3865 tree result;
3868 {
3875 }
3883 }
3885 /* Optimize a bit-field compare.
3887 There are two cases: First is a compare against a constant and the
3888 second is a comparison of two items where the fields are at the same
3889 bit position relative to the start of a chunk (byte, halfword, word)
3890 large enough to contain it. In these cases we can avoid the shift
3891 implicit in bitfield extractions.
3893 For constants, we emit a compare of the shifted constant with the
3894 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3895 compared. For two fields at the same position, we do the ANDs with the
3896 similar mask and compare the result of the ANDs.
3898 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3899 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3900 are the left and right operands of the comparison, respectively.
3902 If the optimization described above can be done, we return the resulting
3903 tree. Otherwise we return zero. */
3905 static tree
3908 {
3917 tree mask;
3918 tree offset;
3920 /* Get all the information about the extractions being done. If the bit size
3921 if the same as the size of the underlying object, we aren't doing an
3922 extraction at all and so can do nothing. We also don't want to
3923 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3924 then will no longer be able to replace it. */
3932 {
3933 /* If this is not a constant, we can only do something if bit positions,
3934 sizes, and signedness are the same. */
3942 }
3944 /* See if we can find a mode to refer to this field. We should be able to,
3945 but fail if we can't. */
3954 /* Set signed and unsigned types of the precision of this mode for the
3955 shifts below. */
3959 /* Compute the bit position and size for the new reference and our offset
3960 within it. If the new reference is the same size as the original, we
3961 won't optimize anything, so return zero. */
3971 /* Make the mask to be used against the extracted field. */
3978 /* If not comparing with constant, just rework the comparison
3979 and return. */
3983 unsigned_type,
3986 mask),
3989 unsigned_type,
3992 mask));
3994 /* Otherwise, we are handling the constant case. See if the constant is too
3995 big for the field. Warn and return a tree of for 0 (false) if so. We do
3996 this not only for its own sake, but to avoid having to test for this
3997 error case below. If we didn't, we might generate wrong code.
3999 For unsigned fields, the constant shifted right by the field length should
4000 be all zero. For signed fields, the high-order bits should agree with
4001 the sign bit. */
4004 {
4008 {
4012 }
4013 }
4014 else
4015 {
4019 {
4023 }
4024 }
4026 /* Single-bit compares should always be against zero. */
4028 {
4031 }
4033 /* Make a new bitfield reference, shift the constant over the
4034 appropriate number of bits and mask it with the computed mask
4035 (in case this was a signed field). If we changed it, make a new one. */
4038 {
4041 }
4051 rhs);
4052 }
4053 \f
4054 /* Subroutine for fold_truthop: decode a field reference.
4056 If EXP is a comparison reference, we return the innermost reference.
4058 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4059 set to the starting bit number.
4061 If the innermost field can be completely contained in a mode-sized
4062 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4064 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4065 otherwise it is not changed.
4067 *PUNSIGNEDP is set to the signedness of the field.
4069 *PMASK is set to the mask used. This is either contained in a
4070 BIT_AND_EXPR or derived from the width of the field.
4072 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4074 Return 0 if this is not a component reference or is one that we can't
4075 do anything with. */
4077 static tree
4082 {
4086 tree unsigned_type;
4089 /* All the optimizations using this function assume integer fields.
4090 There are problems with FP fields since the type_for_size call
4091 below can fail for, e.g., XFmode. */
4095 /* We are interested in the bare arrangement of bits, so strip everything
4096 that doesn't affect the machine mode. However, record the type of the
4097 outermost expression if it may matter below. */
4105 {
4111 }
4120 /* If the number of bits in the reference is the same as the bitsize of
4121 the outer type, then the outer type gives the signedness. Otherwise
4122 (in case of a small bitfield) the signedness is unchanged. */
4126 /* Compute the mask to access the bitfield. */
4135 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4143 }
4145 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4146 bit positions. */
4148 static int
4150 {
4153 tree tmask;
4157 return
4164 }
4166 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4167 represents the sign bit of EXP's type. If EXP represents a sign
4168 or zero extension, also test VAL against the unextended type.
4169 The return value is the (sub)expression whose sign bit is VAL,
4170 or NULL_TREE otherwise. */
4172 static tree
4174 {
4178 tree t;
4180 /* Tree EXP must have an integral type. */
4185 /* Tree VAL must be an integer constant. */
4192 {
4199 }
4200 else
4201 {
4208 }
4210 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
4211 treat VAL as if it were unsigned. */
4216 /* Handle extension from a narrower type. */
4222 }
4224 /* Subroutine for fold_truthop: determine if an operand is simple enough
4225 to be evaluated unconditionally. */
4227 static int
4229 {
4230 /* Strip any conversions that don't change the machine mode. */
4239 /* Don't regard global variables as simple. They may be
4240 allocated in ways unknown to the compiler (shared memory,
4241 #pragma weak, etc). */
4244 /* Loading a static variable is unduly expensive, but global
4245 registers aren't expensive. */
4247 }
4248 \f
4249 /* The following functions are subroutines to fold_range_test and allow it to
4250 try to change a logical combination of comparisons into a range test.
4252 For example, both
4253 X == 2 || X == 3 || X == 4 || X == 5
4254 and
4255 X >= 2 && X <= 5
4256 are converted to
4257 (unsigned) (X - 2) <= 3
4259 We describe each set of comparisons as being either inside or outside
4260 a range, using a variable named like IN_P, and then describe the
4261 range with a lower and upper bound. If one of the bounds is omitted,
4262 it represents either the highest or lowest value of the type.
4264 In the comments below, we represent a range by two numbers in brackets
4265 preceded by a "+" to designate being inside that range, or a "-" to
4266 designate being outside that range, so the condition can be inverted by
4267 flipping the prefix. An omitted bound is represented by a "-". For
4268 example, "- [-, 10]" means being outside the range starting at the lowest
4269 possible value and ending at 10, in other words, being greater than 10.
4270 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4271 always false.
4273 We set up things so that the missing bounds are handled in a consistent
4274 manner so neither a missing bound nor "true" and "false" need to be
4275 handled using a special case. */
4277 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4278 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4279 and UPPER1_P are nonzero if the respective argument is an upper bound
4280 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4281 must be specified for a comparison. ARG1 will be converted to ARG0's
4282 type if both are specified. */
4284 static tree
4287 {
4288 tree tem;
4292 /* If neither arg represents infinity, do the normal operation.
4293 Else, if not a comparison, return infinity. Else handle the special
4294 comparison rules. Note that most of the cases below won't occur, but
4295 are handled for consistency. */
4298 {
4303 }
4308 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4309 for neither. In real maths, we cannot assume open ended ranges are
4310 the same. But, this is computer arithmetic, where numbers are finite.
4311 We can therefore make the transformation of any unbounded range with
4312 the value Z, Z being greater than any representable number. This permits
4313 us to treat unbounded ranges as equal. */
4317 {
4338 }
4341 }
4342 \f
4343 /* Given EXP, a logical expression, set the range it is testing into
4344 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4345 actually being tested. *PLOW and *PHIGH will be made of the same
4346 type as the returned expression. If EXP is not a comparison, we
4347 will most likely not be returning a useful value and range. Set
4348 *STRICT_OVERFLOW_P to true if the return value is only valid
4349 because signed overflow is undefined; otherwise, do not change
4350 *STRICT_OVERFLOW_P. */
4352 static tree
4355 {
4362 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4363 and see if we can refine the range. Some of the cases below may not
4364 happen, but it doesn't seem worth worrying about this. We "continue"
4365 the outer loop when we've changed something; otherwise we "break"
4366 the switch, which will "break" the while. */
4372 {
4377 {
4389 }
4392 {
4399 /* We can only do something if the range is testing for zero
4400 and if the second operand is an integer constant. Note that
4401 saying something is "in" the range we make is done by
4402 complementing IN_P since it will set in the initial case of
4403 being not equal to zero; "out" is leaving it alone. */
4410 {
4431 }
4433 /* If this is an unsigned comparison, we also know that EXP is
4434 greater than or equal to zero. We base the range tests we make
4435 on that fact, so we record it here so we can parse existing
4436 range tests. We test arg0_type since often the return type
4437 of, e.g. EQ_EXPR, is boolean. */
4439 {
4443 NULL_TREE))
4448 /* If the high bound is missing, but we have a nonzero low
4449 bound, reverse the range so it goes from zero to the low bound
4450 minus 1. */
4452 {
4457 }
4458 }
4464 /* (-x) IN [a,b] -> x in [-b, -a] */
4476 /* ~ X -> -X - 1 */
4485 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4486 move a constant to the other side. */
4491 /* If EXP is signed, any overflow in the computation is undefined,
4492 so we don't worry about it so long as our computations on
4493 the bounds don't overflow. For unsigned, overflow is defined
4494 and this is exactly the right thing. */
4506 /* Check for an unsigned range which has wrapped around the maximum
4507 value thus making n_high < n_low, and normalize it. */
4509 {
4515 /* If the range is of the form +/- [ x+1, x ], we won't
4516 be able to normalize it. But then, it represents the
4517 whole range or the empty set, so make it
4518 +/- [ -, - ]. */
4522 else
4524 }
4525 else
4549 /* If we're converting arg0 from an unsigned type, to exp,
4550 a signed type, we will be doing the comparison as unsigned.
4551 The tests above have already verified that LOW and HIGH
4552 are both positive.
4554 So we have to ensure that we will handle large unsigned
4555 values the same way that the current signed bounds treat
4556 negative values. */
4559 {
4560 tree high_positive;
4561 tree equiv_type;
4562 /* For fixed-point modes, we need to pass the saturating flag
4563 as the 2nd parameter. */
4568 else
4572 /* A range without an upper bound is, naturally, unbounded.
4573 Since convert would have cropped a very large value, use
4574 the max value for the destination type. */
4575 high_positive
4582 high_positive),
4585 /* If the low bound is specified, "and" the range with the
4586 range for which the original unsigned value will be
4587 positive. */
4589 {
4593 integer_zero_node),
4594 high_positive))
4598 }
4599 else
4600 {
4601 /* Otherwise, "or" the range with the range of the input
4602 that will be interpreted as negative. */
4606 integer_zero_node),
4607 high_positive))
4611 }
4612 }
4620 }
4623 }
4625 /* If EXP is a constant, we can evaluate whether this is true or false. */
4627 {
4634 }
4638 }
4639 \f
4640 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4641 type, TYPE, return an expression to test if EXP is in (or out of, depending
4642 on IN_P) the range. Return 0 if the test couldn't be created. */
4644 static tree
4646 {
4648 tree value;
4650 #ifdef HAVE_canonicalize_funcptr_for_compare
4651 /* Disable this optimization for function pointer expressions
4652 on targets that require function pointer canonicalization. */
4657 #endif
4660 {
4666 }
4684 {
4686 {
4690 }
4692 }
4694 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4696 {
4698 HOST_WIDE_INT hi;
4703 {
4706 }
4707 else
4708 {
4711 }
4714 {
4716 {
4719 }
4722 }
4723 }
4725 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4726 This requires wrap-around arithmetics for the type of the expression. */
4728 {
4730 /* There is no requirement that LOW be within the range of ETYPE
4731 if the latter is a subtype. It must, however, be within the base
4732 type of ETYPE. So be sure we do the subtraction in that type. */
4745 }
4747 /* If we don't have wrap-around arithmetics upfront, try to force it. */
4750 {
4753 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4754 for the type in question, as we rely on this here. */
4764 else
4766 }
4776 {
4778 {
4784 }
4786 }
4794 }
4795 \f
4796 /* Return the predecessor of VAL in its type, handling the infinite case. */
4798 static tree
4800 {
4806 else
4808 }
4810 /* Return the successor of VAL in its type, handling the infinite case. */
4812 static tree
4814 {
4820 else
4822 }
4824 /* Given two ranges, see if we can merge them into one. Return 1 if we
4825 can, 0 if we can't. Set the output range into the specified parameters. */
4827 static int
4830 {
4834 tree tem;
4844 /* Make range 0 be the range that starts first, or ends last if they
4845 start at the same value. Swap them if it isn't. */
4848 || (lowequal
4851 {
4855 }
4857 /* Now flag two cases, whether the ranges are disjoint or whether the
4858 second range is totally subsumed in the first. Note that the tests
4859 below are simplified by the ones above. */
4865 /* We now have four cases, depending on whether we are including or
4866 excluding the two ranges. */
4868 {
4869 /* If they don't overlap, the result is false. If the second range
4870 is a subset it is the result. Otherwise, the range is from the start
4871 of the second to the end of the first. */
4876 else
4878 }
4881 {
4882 /* If they don't overlap, the result is the first range. If they are
4883 equal, the result is false. If the second range is a subset of the
4884 first, and the ranges begin at the same place, we go from just after
4885 the end of the second range to the end of the first. If the second
4886 range is not a subset of the first, or if it is a subset and both
4887 ranges end at the same place, the range starts at the start of the
4888 first range and ends just before the second range.
4889 Otherwise, we can't describe this as a single range. */
4895 {
4900 {
4901 /* We are in the weird situation where high0 > high1 but
4902 high1 has no successor. Punt. */
4904 }
4905 }
4907 {
4912 {
4913 /* low0 < low1 but low1 has no predecessor. Punt. */
4915 }
4916 }
4917 else
4919 }
4922 {
4923 /* If they don't overlap, the result is the second range. If the second
4924 is a subset of the first, the result is false. Otherwise,
4925 the range starts just after the first range and ends at the
4926 end of the second. */
4931 else
4932 {
4937 {
4938 /* high1 > high0 but high0 has no successor. Punt. */
4940 }
4941 }
4942 }
4944 else
4945 {
4946 /* The case where we are excluding both ranges. Here the complex case
4947 is if they don't overlap. In that case, the only time we have a
4948 range is if they are adjacent. If the second is a subset of the
4949 first, the result is the first. Otherwise, the range to exclude
4950 starts at the beginning of the first range and ends at the end of the
4951 second. */
4953 {
4958 else
4959 {
4960 /* Canonicalize - [min, x] into - [-, x]. */
4963 {
4968 /* FALLTHROUGH */
4981 }
4983 /* Canonicalize - [x, max] into - [x, -]. */
4986 {
4991 /* FALLTHROUGH */
5006 }
5008 /* The ranges might be also adjacent between the maximum and
5009 minimum values of the given type. For
5010 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5011 return + [x + 1, y - 1]. */
5013 {
5020 }
5021 else
5023 }
5024 }
5027 else
5029 }
5033 }
5034 \f
5036 /* Subroutine of fold, looking inside expressions of the form
5037 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5038 of the COND_EXPR. This function is being used also to optimize
5039 A op B ? C : A, by reversing the comparison first.
5041 Return a folded expression whose code is not a COND_EXPR
5042 anymore, or NULL_TREE if no folding opportunity is found. */
5044 static tree
5046 {
5051 tree tem;
5056 /* If we have A op 0 ? A : -A, consider applying the following
5057 transformations:
5059 A == 0? A : -A same as -A
5060 A != 0? A : -A same as A
5061 A >= 0? A : -A same as abs (A)
5062 A > 0? A : -A same as abs (A)
5063 A <= 0? A : -A same as -abs (A)
5064 A < 0? A : -A same as -abs (A)
5066 None of these transformations work for modes with signed
5067 zeros. If A is +/-0, the first two transformations will
5068 change the sign of the result (from +0 to -0, or vice
5069 versa). The last four will fix the sign of the result,
5070 even though the original expressions could be positive or
5071 negative, depending on the sign of A.
5073 Note that all these transformations are correct if A is
5074 NaN, since the two alternatives (A and -A) are also NaNs. */
5080 /* In the case that A is of the form X-Y, '-A' (arg2) may
5081 have already been folded to Y-X, check for that. */
5089 {
5101 /* Fall through. */
5123 }
5125 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5126 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5127 both transformations are correct when A is NaN: A != 0
5128 is then true, and A == 0 is false. */
5131 {
5136 }
5138 /* Try some transformations of A op B ? A : B.
5140 A == B? A : B same as B
5141 A != B? A : B same as A
5142 A >= B? A : B same as max (A, B)
5143 A > B? A : B same as max (B, A)
5144 A <= B? A : B same as min (A, B)
5145 A < B? A : B same as min (B, A)
5147 As above, these transformations don't work in the presence
5148 of signed zeros. For example, if A and B are zeros of
5149 opposite sign, the first two transformations will change
5150 the sign of the result. In the last four, the original
5151 expressions give different results for (A=+0, B=-0) and
5152 (A=-0, B=+0), but the transformed expressions do not.
5154 The first two transformations are correct if either A or B
5155 is a NaN. In the first transformation, the condition will
5156 be false, and B will indeed be chosen. In the case of the
5157 second transformation, the condition A != B will be true,
5158 and A will be chosen.
5160 The conversions to max() and min() are not correct if B is
5161 a number and A is not. The conditions in the original
5162 expressions will be false, so all four give B. The min()
5163 and max() versions would give a NaN instead. */
5165 /* Avoid these transformations if the COND_EXPR may be used
5166 as an lvalue in the C++ front-end. PR c++/19199. */
5167 && (in_gimple_form
5172 {
5177 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
5179 {
5183 }
5186 {
5195 /* In C++ a ?: expression can be an lvalue, so put the
5196 operand which will be used if they are equal first
5197 so that we can convert this back to the
5198 corresponding COND_EXPR. */
5200 {
5207 }
5214 {
5221 }
5234 }
5235 }
5237 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5238 we might still be able to simplify this. For example,
5239 if C1 is one less or one more than C2, this might have started
5240 out as a MIN or MAX and been transformed by this function.
5241 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5247 {
5249 /* We can replace A with C1 in this case. */
5254 /* If C1 is C2 + 1, this is min(A, C2). */
5256 OEP_ONLY_CONST)
5260 OEP_ONLY_CONST))
5262 type,
5264 arg2));
5268 /* If C1 is C2 - 1, this is min(A, C2). */
5270 OEP_ONLY_CONST)
5274 OEP_ONLY_CONST))
5276 type,
5278 arg2));
5282 /* If C1 is C2 - 1, this is max(A, C2). */
5284 OEP_ONLY_CONST)
5288 OEP_ONLY_CONST))
5290 type,
5292 arg2));
5296 /* If C1 is C2 + 1, this is max(A, C2). */
5298 OEP_ONLY_CONST)
5302 OEP_ONLY_CONST))
5304 type,
5306 arg2));
5312 }
5315 }
5318 \f
5319 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5320 #define LOGICAL_OP_NON_SHORT_CIRCUIT (BRANCH_COST >= 2)
5321 #endif
5323 /* EXP is some logical combination of boolean tests. See if we can
5324 merge it into some range test. Return the new tree if so. */
5326 static tree
5328 {
5336 tree tem;
5340 /* If this is an OR operation, invert both sides; we will invert
5341 again at the end. */
5345 /* If both expressions are the same, if we can merge the ranges, and we
5346 can build the range test, return it or it inverted. If one of the
5347 ranges is always true or always false, consider it to be the same
5348 expression as the other. */
5356 {
5360 }
5362 /* On machines where the branch cost is expensive, if this is a
5363 short-circuited branch and the underlying object on both sides
5364 is the same, make a non-short-circuit operation. */
5370 {
5371 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5372 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5373 which cases we can't do this. */
5381 {
5390 {
5393 WARN_STRICT_OVERFLOW_COMPARISON);
5397 }
5398 }
5399 }
5402 }
5403 \f
5404 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
5405 bit value. Arrange things so the extra bits will be set to zero if and
5406 only if C is signed-extended to its full width. If MASK is nonzero,
5407 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5409 static tree
5411 {
5414 tree temp;
5419 /* We work by getting just the sign bit into the low-order bit, then
5420 into the high-order bit, then sign-extend. We then XOR that value
5421 with C. */
5425 /* We must use a signed type in order to get an arithmetic right shift.
5426 However, we must also avoid introducing accidental overflows, so that
5427 a subsequent call to integer_zerop will work. Hence we must
5428 do the type conversion here. At this point, the constant is either
5429 zero or one, and the conversion to a signed type can never overflow.
5430 We could get an overflow if this conversion is done anywhere else. */
5439 /* If necessary, convert the type back to match the type of C. */
5444 }
5445 \f
5446 /* Find ways of folding logical expressions of LHS and RHS:
5447 Try to merge two comparisons to the same innermost item.
5448 Look for range tests like "ch >= '0' && ch <= '9'".
5449 Look for combinations of simple terms on machines with expensive branches
5450 and evaluate the RHS unconditionally.
5452 For example, if we have p->a == 2 && p->b == 4 and we can make an
5453 object large enough to span both A and B, we can do this with a comparison
5454 against the object ANDed with the a mask.
5456 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5457 operations to do this with one comparison.
5459 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5460 function and the one above.
5462 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5463 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5465 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5466 two operands.
5468 We return the simplified tree or 0 if no optimization is possible. */
5470 static tree
5472 {
5473 /* If this is the "or" of two comparisons, we can do something if
5474 the comparisons are NE_EXPR. If this is the "and", we can do something
5475 if the comparisons are EQ_EXPR. I.e.,
5476 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5478 WANTED_CODE is this operation code. For single bit fields, we can
5479 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5480 comparison for one-bit fields. */
5502 /* Start by getting the comparison codes. Fail if anything is volatile.
5503 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5504 it were surrounded with a NE_EXPR. */
5513 {
5517 }
5520 {
5524 }
5535 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5538 {
5539 tree result;
5542 {
5547 }
5550 {
5556 }
5557 }
5562 /* If the RHS can be evaluated unconditionally and its operands are
5563 simple, it wins to evaluate the RHS unconditionally on machines
5564 with expensive branches. In this case, this isn't a comparison
5565 that can be merged. Avoid doing this if the RHS is a floating-point
5566 comparison since those can trap. */
5572 {
5573 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5583 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5594 {
5598 }
5599 }
5601 /* See if the comparisons can be merged. Then get all the parameters for
5602 each side. */
5626 /* It must be true that the inner operation on the lhs of each
5627 comparison must be the same if we are to be able to do anything.
5628 Then see if we have constants. If not, the same must be true for
5629 the rhs's. */
5640 else
5643 /* If either comparison code is not correct for our logical operation,
5644 fail. However, we can convert a one-bit comparison against zero into
5645 the opposite comparison against that bit being set in the field. */
5649 {
5651 {
5652 /* Make the left operand unsigned, since we are only interested
5653 in the value of one bit. Otherwise we are doing the wrong
5654 thing below. */
5657 }
5658 else
5660 }
5662 /* This is analogous to the code for l_const above. */
5664 {
5666 {
5669 }
5670 else
5672 }
5674 /* See if we can find a mode that contains both fields being compared on
5675 the left. If we can't, fail. Otherwise, update all constants and masks
5676 to be relative to a field of that size. */
5681 volatilep);
5691 {
5694 }
5702 {
5710 {
5714 }
5715 }
5717 {
5725 {
5729 }
5730 }
5732 /* If the right sides are not constant, do the same for it. Also,
5733 disallow this optimization if a size or signedness mismatch occurs
5734 between the left and right sides. */
5736 {
5739 /* Make sure the two fields on the right
5740 correspond to the left without being swapped. */
5748 volatilep);
5758 {
5761 }
5768 /* Make a mask that corresponds to both fields being compared.
5769 Do this for both items being compared. If the operands are the
5770 same size and the bits being compared are in the same position
5771 then we can do this by masking both and comparing the masked
5772 results. */
5776 {
5788 }
5790 /* There is still another way we can do something: If both pairs of
5791 fields being compared are adjacent, we may be able to make a wider
5792 field containing them both.
5794 Note that we still must mask the lhs/rhs expressions. Furthermore,
5795 the mask must be shifted to account for the shift done by
5796 make_bit_field_ref. */
5801 {
5802 tree type;
5814 /* Convert to the smaller type before masking out unwanted bits. */
5817 {
5819 {
5823 }
5825 {
5829 }
5830 }
5839 }
5842 }
5844 /* Handle the case of comparisons with constants. If there is something in
5845 common between the masks, those bits of the constants must be the same.
5846 If not, the condition is always false. Test for this to avoid generating
5847 incorrect code below. */
5852 {
5854 {
5857 }
5858 else
5859 {
5862 }
5863 }
5865 /* Construct the expression we will return. First get the component
5866 reference we will make. Unless the mask is all ones the width of
5867 that field, perform the mask operation. Then compare with the
5868 merged constant. */
5878 }
5879 \f
5880 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5881 constant. */
5883 static tree
5885 {
5889 tree minmax_const;
5891 tree inner;
5901 /* If something does not permit us to optimize, return the original tree. */
5909 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5910 and GT_EXPR, doing the rest with recursive calls using logical
5911 simplifications. */
5913 {
5915 {
5921 }
5924 return
5926 optimize_minmax_comparison
5928 optimize_minmax_comparison
5933 /* MAX (X, 0) == 0 -> X <= 0 */
5937 /* MAX (X, 0) == 5 -> X == 5 */
5941 /* MAX (X, 0) == -1 -> false */
5945 /* MIN (X, 0) == 0 -> X >= 0 */
5949 /* MIN (X, 0) == 5 -> false */
5952 else
5953 /* MIN (X, 0) == -1 -> X == -1 */
5958 /* MAX (X, 0) > 0 -> X > 0
5959 MAX (X, 0) > 5 -> X > 5 */
5963 /* MAX (X, 0) > -1 -> true */
5967 /* MIN (X, 0) > 0 -> false
5968 MIN (X, 0) > 5 -> false */
5971 else
5972 /* MIN (X, 0) > -1 -> X > -1 */
5977 }
5978 }
5979 \f
5980 /* T is an integer expression that is being multiplied, divided, or taken a
5981 modulus (CODE says which and what kind of divide or modulus) by a
5982 constant C. See if we can eliminate that operation by folding it with
5983 other operations already in T. WIDE_TYPE, if non-null, is a type that
5984 should be used for the computation if wider than our type.
5986 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5987 (X * 2) + (Y * 4). We must, however, be assured that either the original
5988 expression would not overflow or that overflow is undefined for the type
5989 in the language in question.
5991 We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
5992 the machine has a multiply-accumulate insn or that this is part of an
5993 addressing calculation.
5995 If we return a non-null expression, it is an equivalent form of the
5996 original computation, but need not be in the original type.
5998 We set *STRICT_OVERFLOW_P to true if the return values depends on
5999 signed overflow being undefined. Otherwise we do not change
6000 *STRICT_OVERFLOW_P. */
6002 static tree
6005 {
6006 /* To avoid exponential search depth, refuse to allow recursion past
6007 three levels. Beyond that (1) it's highly unlikely that we'll find
6008 something interesting and (2) we've probably processed it before
6009 when we built the inner expression. */
6012 tree ret;
6017 depth++;
6019 depth--;
6022 }
6024 static tree
6027 {
6038 /* Don't deal with constants of zero here; they confuse the code below. */
6048 /* Note that we need not handle conditional operations here since fold
6049 already handles those cases. So just do arithmetic here. */
6051 {
6053 /* For a constant, we can always simplify if we are a multiply
6054 or (for divide and modulus) if it is a multiple of our constant. */
6062 /* If op0 is an expression ... */
6068 /* ... and is unsigned, and its type is smaller than ctype,
6069 then we cannot pass through as widening. */
6075 /* ... or this is a truncation (t is narrower than op0),
6076 then we cannot pass through this narrowing. */
6079 /* ... or signedness changes for division or modulus,
6080 then we cannot pass through this conversion. */
6084 /* ... or has undefined overflow while the converted to
6085 type has not, we cannot do the operation in the inner type
6086 as that would introduce undefined overflow. */
6091 /* Pass the constant down and see if we can make a simplification. If
6092 we can, replace this expression with the inner simplification for
6093 possible later conversion to our or some other type. */
6098 code == MULT_EXPR
6100 strict_overflow_p))))
6105 /* If widening the type changes it from signed to unsigned, then we
6106 must avoid building ABS_EXPR itself as unsigned. */
6108 {
6112 {
6115 }
6117 }
6118 /* If the constant is negative, we cannot simplify this. */
6121 /* FALLTHROUGH */
6129 /* If widening the type changes the signedness, then we can't perform
6130 this optimization as that changes the result. */
6134 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6140 {
6147 }
6151 /* If the second operand is constant, this is a multiplication
6152 or floor division, by a power of two, so we can treat it that
6153 way unless the multiplier or divisor overflows. Signed
6154 left-shift overflow is implementation-defined rather than
6155 undefined in C90, so do not convert signed left shift into
6156 multiplication. */
6159 /* const_binop may not detect overflow correctly,
6160 so check for it explicitly here. */
6165 size_one_node,
6175 /* See if we can eliminate the operation on both sides. If we can, we
6176 can return a new PLUS or MINUS. If we can't, the only remaining
6177 cases where we can do anything are if the second operand is a
6178 constant. */
6184 /* If not multiplication, we can only do this if both operands
6185 are divisible by c. */
6188 {
6193 }
6195 /* If this was a subtraction, negate OP1 and set it to be an addition.
6196 This simplifies the logic below. */
6203 /* If either OP1 or C are negative, this optimization is not safe for
6204 some of the division and remainder types while for others we need
6205 to change the code. */
6207 {
6215 }
6217 /* If it's a multiply or a division/modulus operation of a multiple
6218 of our constant, do the operation and verify it doesn't overflow. */
6221 {
6224 /* We allow the constant to overflow with wrapping semantics. */
6228 }
6229 else
6232 /* If we have an unsigned type is not a sizetype, we cannot widen
6233 the operation since it will change the result if the original
6234 computation overflowed. */
6240 /* If we were able to eliminate our operation from the first side,
6241 apply our operation to the second side and reform the PLUS. */
6245 /* The last case is if we are a multiply. In that case, we can
6246 apply the distributive law to commute the multiply and addition
6247 if the multiplication of the constants doesn't overflow. */
6253 op1);
6258 /* We have a special case here if we are doing something like
6259 (C * 8) % 4 since we know that's zero. */
6266 /* ... fall through ... */
6270 /* If we can extract our operation from the LHS, do so and return a
6271 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6272 do something only if the second operand is a constant. */
6286 /* If these are the same operation types, we can associate them
6287 assuming no overflow. */
6294 /* If these operations "cancel" each other, we have the main
6295 optimizations of this pass, which occur when either constant is a
6296 multiple of the other, in which case we replace this with either an
6297 operation or CODE or TCODE.
6299 If we have an unsigned type that is not a sizetype, we cannot do
6300 this since it will change the result if the original computation
6301 overflowed. */
6309 {
6311 {
6318 }
6320 {
6327 }
6328 }
6333 }
6336 }
6337 \f
6338 /* Return a node which has the indicated constant VALUE (either 0 or
6339 1), and is of the indicated TYPE. */
6341 tree
6343 {
6348 else
6350 }
6353 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6354 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6355 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6356 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6357 COND is the first argument to CODE; otherwise (as in the example
6358 given here), it is the second argument. TYPE is the type of the
6359 original expression. Return NULL_TREE if no simplification is
6360 possible. */
6362 static tree
6366 {
6373 /* This transformation is only worthwhile if we don't have to wrap
6374 arg in a SAVE_EXPR, and the operation can be simplified on at least
6375 one of the branches once its pushed inside the COND_EXPR. */
6380 {
6384 /* If this operand throws an expression, then it does not make
6385 sense to try to perform a logical or arithmetic operation
6386 involving it. */
6391 }
6392 else
6393 {
6398 }
6402 {
6406 else
6408 }
6410 {
6414 else
6416 }
6420 }
6422 \f
6423 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6425 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6426 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6427 ADDEND is the same as X.
6429 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6430 and finite. The problematic cases are when X is zero, and its mode
6431 has signed zeros. In the case of rounding towards -infinity,
6432 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6433 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6435 bool
6437 {
6441 /* Don't allow the fold with -fsignaling-nans. */
6445 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6449 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6454 /* The mode has signed zeros, and we have to honor their sign.
6455 In this situation, there is only one case we can return true for.
6456 X - 0 is the same as X unless rounding towards -infinity is
6457 supported. */
6459 }
6461 /* Subroutine of fold() that checks comparisons of built-in math
6462 functions against real constants.
6464 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6465 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6466 is the type of the result and ARG0 and ARG1 are the operands of the
6467 comparison. ARG1 must be a TREE_REAL_CST.
6469 The function returns the constant folded tree if a simplification
6470 can be made, and NULL_TREE otherwise. */
6472 static tree
6475 {
6476 REAL_VALUE_TYPE c;
6479 {
6485 {
6486 /* sqrt(x) < y is always false, if y is negative. */
6490 /* sqrt(x) > y is always true, if y is negative and we
6491 don't care about NaNs, i.e. negative values of x. */
6495 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6498 }
6500 {
6501 REAL_VALUE_TYPE c2;
6507 {
6508 /* sqrt(x) > y is x == +Inf, when y is very large. */
6513 /* sqrt(x) > y is always false, when y is very large
6514 and we don't care about infinities. */
6516 }
6518 /* sqrt(x) > c is the same as x > c*c. */
6521 }
6523 {
6524 REAL_VALUE_TYPE c2;
6530 {
6531 /* sqrt(x) < y is always true, when y is a very large
6532 value and we don't care about NaNs or Infinities. */
6536 /* sqrt(x) < y is x != +Inf when y is very large and we
6537 don't care about NaNs. */
6542 /* sqrt(x) < y is x >= 0 when y is very large and we
6543 don't care about Infinities. */
6548 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6557 dconst0)),
6560 c2)));
6561 }
6563 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6568 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6571 {
6576 dconst0)),
6579 c2)));
6580 }
6581 }
6582 }
6585 }
6587 /* Subroutine of fold() that optimizes comparisons against Infinities,
6588 either +Inf or -Inf.
6590 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6591 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6592 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6594 The function returns the constant folded tree if a simplification
6595 can be made, and NULL_TREE otherwise. */
6597 static tree
6599 {
6601 REAL_VALUE_TYPE max;
6602 tree temp;
6607 /* For negative infinity swap the sense of the comparison. */
6613 {
6615 /* x > +Inf is always false, if with ignore sNANs. */
6621 /* x <= +Inf is always true, if we don't case about NaNs. */
6625 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6628 {
6631 }
6636 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6642 /* x < +Inf is always equal to x <= DBL_MAX. */
6648 /* x != +Inf is always equal to !(x > DBL_MAX). */
6660 }
6663 }
6665 /* Subroutine of fold() that optimizes comparisons of a division by
6666 a nonzero integer constant against an integer constant, i.e.
6667 X/C1 op C2.
6669 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6670 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6671 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6673 The function returns the constant folded tree if a simplification
6674 can be made, and NULL_TREE otherwise. */
6676 static tree
6678 {
6683 HOST_WIDE_INT hpart;
6688 /* We have to do this the hard way to detect unsigned overflow.
6689 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6700 {
6705 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6713 }
6715 {
6719 {
6738 }
6739 }
6740 else
6741 {
6742 /* A negative divisor reverses the relational operators. */
6748 {
6767 }
6768 }
6771 {
6792 {
6795 }
6800 {
6803 }
6808 {
6811 }
6816 {
6819 }
6824 }
6827 }
6830 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6831 equality/inequality test, then return a simplified form of the test
6832 using a sign testing. Otherwise return NULL. TYPE is the desired
6833 result type. */
6835 static tree
6837 tree result_type)
6838 {
6839 /* If this is testing a single bit, we can optimize the test. */
6843 {
6844 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6845 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6849 /* This is only a win if casting to a signed type is cheap,
6850 i.e. when arg00's type is not a partial mode. */
6853 {
6858 }
6859 }
6862 }
6864 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6865 equality/inequality test, then return a simplified form of
6866 the test using shifts and logical operations. Otherwise return
6867 NULL. TYPE is the desired result type. */
6869 tree
6871 tree result_type)
6872 {
6873 /* If this is testing a single bit, we can optimize the test. */
6877 {
6886 /* First, see if we can fold the single bit test into a sign-bit
6887 test. */
6889 result_type);
6893 /* Otherwise we have (A & C) != 0 where C is a single bit,
6894 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6895 Similarly for (A & C) == 0. */
6897 /* If INNER is a right shift of a constant and it plus BITNUM does
6898 not overflow, adjust BITNUM and INNER. */
6905 {
6908 }
6910 /* If we are going to be able to omit the AND below, we must do our
6911 operations as unsigned. If we must use the AND, we have a choice.
6912 Normally unsigned is faster, but for some machines signed is. */
6913 #ifdef LOAD_EXTEND_OP
6916 #else
6918 #endif
6934 /* Put the AND last so it can combine with more things. */
6937 /* Make sure to return the proper type. */
6941 }
6943 }
6945 /* Check whether we are allowed to reorder operands arg0 and arg1,
6946 such that the evaluation of arg1 occurs before arg0. */
6948 static bool
6950 {
6957 }
6959 /* Test whether it is preferable two swap two operands, ARG0 and
6960 ARG1, for example because ARG0 is an integer constant and ARG1
6961 isn't. If REORDER is true, only recommend swapping if we can
6962 evaluate the operands in reverse order. */
6964 bool
6966 {
7002 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7003 for commutative and comparison operators. Ensuring a canonical
7004 form allows the optimizers to find additional redundancies without
7005 having to explicitly check for both orderings. */
7011 /* Put SSA_NAMEs last. */
7017 /* Put variables last. */
7024 }
7026 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
7027 ARG0 is extended to a wider type. */
7029 static tree
7031 {
7033 tree arg1_unw;
7042 #ifdef HAVE_canonicalize_funcptr_for_compare
7043 /* Disable this optimization if we're casting a function pointer
7044 type on targets that require function pointer canonicalization. */
7049 #endif
7056 /* If possible, express the comparison in the shorter mode. */
7074 /* If we are comparing with the integer that does not fit into the range
7075 of the shorter type, the result is known. */
7086 {
7113 }
7116 }
7118 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
7119 ARG0 just the signedness is changed. */
7121 static tree
7124 {
7125 tree arg0_inner;
7136 #ifdef HAVE_canonicalize_funcptr_for_compare
7137 /* Disable this optimization if we're casting a function pointer
7138 type on targets that require function pointer canonicalization. */
7143 #endif
7163 else
7167 }
7169 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
7170 step of the array. Reconstructs s and delta in the case of s * delta
7171 being an integer constant (and thus already folded).
7172 ADDR is the address. MULT is the multiplicative expression.
7173 If the function succeeds, the new address expression is returned. Otherwise
7174 NULL_TREE is returned. */
7176 static tree
7178 {
7182 tree itype;
7185 /* Strip the nops that might be added when converting op1 to sizetype. */
7188 /* Canonicalize op1 into a possibly non-constant delta
7189 and an INTEGER_CST s. */
7191 {
7198 {
7201 }
7203 {
7206 }
7207 else
7209 }
7211 {
7214 }
7215 else
7216 {
7217 /* Simulate we are delta * 1. */
7220 }
7223 {
7225 {
7226 /* Remember if this was a multi-dimensional array. */
7239 {
7242 }
7243 else
7244 {
7245 /* Try if delta is a multiple of step. */
7250 }
7252 /* Only fold here if we can verify we do not overflow one
7253 dimension of a multi-dimensional array. */
7255 {
7256 tree tmp;
7272 }
7275 }
7276 else
7281 }
7283 /* We found the suitable array reference. So copy everything up to it,
7284 and replace the index. */
7291 {
7295 }
7303 }
7306 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7307 means A >= Y && A != MAX, but in this case we know that
7308 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7310 static tree
7312 {
7319 else
7328 {
7331 }
7333 {
7336 }
7337 else
7344 {
7345 /* Convert the pointer types into integer before taking the difference. */
7349 }
7350 else
7357 }
7359 /* Fold a sum or difference of at least one multiplication.
7360 Returns the folded tree or NULL if no simplification could be made. */
7362 static tree
7364 {
7368 /* (A * C) +- (B * C) -> (A+-B) * C.
7369 (A * C) +- A -> A * (C+-1).
7370 We are most concerned about the case where C is a constant,
7371 but other combinations show up during loop reduction. Since
7372 it is not difficult, try all four possibilities. */
7375 {
7378 }
7380 {
7383 }
7384 else
7385 {
7386 /* We cannot generate constant 1 for fract. */
7391 }
7393 {
7396 }
7398 {
7401 }
7402 else
7403 {
7404 /* We cannot generate constant 1 for fract. */
7409 }
7421 /* No identical multiplicands; see if we can find a common
7422 power-of-two factor in non-power-of-two multiplies. This
7423 can help in multi-dimensional array access. */
7426 {
7429 tree maybe_same;
7433 /* Move min of absolute values to int11. */
7436 {
7441 }
7442 else
7446 {
7454 }
7455 }
7465 }
7467 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7468 specified by EXPR into the buffer PTR of length LEN bytes.
7469 Return the number of bytes placed in the buffer, or zero
7470 upon failure. */
7472 static int
7474 {
7485 {
7489 else
7494 {
7501 else
7503 }
7504 else
7507 }
7509 }
7512 /* Subroutine of native_encode_expr. Encode the REAL_CST
7513 specified by EXPR into the buffer PTR of length LEN bytes.
7514 Return the number of bytes placed in the buffer, or zero
7515 upon failure. */
7517 static int
7519 {
7525 /* There are always 32 bits in each long, no matter the size of
7526 the hosts long. We handle floating point representations with
7527 up to 192 bits. */
7538 {
7543 {
7550 else
7552 }
7553 else
7556 }
7558 }
7560 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7561 specified by EXPR into the buffer PTR of length LEN bytes.
7562 Return the number of bytes placed in the buffer, or zero
7563 upon failure. */
7565 static int
7567 {
7569 tree part;
7580 }
7583 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7584 specified by EXPR into the buffer PTR of length LEN bytes.
7585 Return the number of bytes placed in the buffer, or zero
7586 upon failure. */
7588 static int
7590 {
7600 {
7602 {
7605 }
7606 else
7610 {
7613 }
7614 else
7615 {
7619 }
7621 }
7623 }
7626 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7627 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7628 buffer PTR of length LEN bytes. Return the number of bytes
7629 placed in the buffer, or zero upon failure. */
7631 int
7633 {
7635 {
7650 }
7651 }
7654 /* Subroutine of native_interpret_expr. Interpret the contents of
7655 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7656 If the buffer cannot be interpreted, return NULL_TREE. */
7658 static tree
7660 {
7674 {
7677 {
7684 else
7686 }
7687 else
7693 else
7696 }
7699 }
7702 /* Subroutine of native_interpret_expr. Interpret the contents of
7703 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7704 If the buffer cannot be interpreted, return NULL_TREE. */
7706 static tree
7708 {
7713 /* There are always 32 bits in each long, no matter the size of
7714 the hosts long. We handle floating point representations with
7715 up to 192 bits. */
7716 REAL_VALUE_TYPE r;
7727 {
7730 {
7737 else
7739 }
7740 else
7745 }
7749 }
7752 /* Subroutine of native_interpret_expr. Interpret the contents of
7753 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7754 If the buffer cannot be interpreted, return NULL_TREE. */
7756 static tree
7758 {
7773 }
7776 /* Subroutine of native_interpret_expr. Interpret the contents of
7777 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7778 If the buffer cannot be interpreted, return NULL_TREE. */
7780 static tree
7782 {
7794 {
7799 }
7801 }
7804 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7805 the buffer PTR of length LEN as a constant of type TYPE. For
7806 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7807 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7808 return NULL_TREE. */
7810 tree
7812 {
7814 {
7831 }
7832 }
7835 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7836 TYPE at compile-time. If we're unable to perform the conversion
7837 return NULL_TREE. */
7839 static tree
7841 {
7842 /* We support up to 512-bit values (for V8DFmode). */
7846 /* Check that the host and target are sane. */
7855 }
7857 /* Build an expression for the address of T. Folds away INDIRECT_REF
7858 to avoid confusing the gimplify process. When IN_FOLD is true
7859 avoid modifications of T. */
7861 static tree
7863 {
7864 /* The size of the object is not relevant when talking about its address. */
7868 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7871 {
7876 }
7878 {
7888 }
7889 else
7893 }
7895 /* Build an expression for the address of T with type PTRTYPE. This
7896 function modifies the input parameter 'T' by sometimes setting the
7897 TREE_ADDRESSABLE flag. */
7899 tree
7901 {
7903 }
7905 /* Build an expression for the address of T. This function modifies
7906 the input parameter 'T' by sometimes setting the TREE_ADDRESSABLE
7907 flag. When called from fold functions, use fold_addr_expr instead. */
7909 tree
7911 {
7915 }
7917 /* Same as build_fold_addr_expr, builds an expression for the address
7918 of T, but avoids touching the input node 't'. Fold functions
7919 should use this version. */
7921 static tree
7923 {
7927 }
7929 /* Fold a unary expression of code CODE and type TYPE with operand
7930 OP0. Return the folded expression if folding is successful.
7931 Otherwise, return NULL_TREE. */
7933 tree
7935 {
7936 tree tem;
7937 tree arg0;
7945 {
7948 {
7949 /* Don't use STRIP_NOPS, because signedness of argument type
7950 matters. */
7952 }
7953 else
7954 {
7955 /* Strip any conversions that don't change the mode. This
7956 is safe for every expression, except for a comparison
7957 expression because its signedness is derived from its
7958 operands.
7960 Note that this is done as an internal manipulation within
7961 the constant folder, in order to find the simplest
7962 representation of the arguments so that their form can be
7963 studied. In any cases, the appropriate type conversions
7964 should be put back in the tree that will get out of the
7965 constant folder. */
7967 }
7968 }
7971 {
7976 {
7986 /* If this was a conversion, and all we did was to move into
7987 inside the COND_EXPR, bring it back out. But leave it if
7988 it is a conversion from integer to integer and the
7989 result precision is no wider than a word since such a
7990 conversion is cheap and may be optimized away by combine,
7991 while it couldn't if it were outside the COND_EXPR. Then return
7992 so we don't get into an infinite recursion loop taking the
7993 conversion out and then back in. */
8005 && (INTEGRAL_TYPE_P
8017 }
8019 {
8021 {
8025 }
8029 integer_one_node),
8031 integer_zero_node));
8032 }
8033 }
8036 {
8038 /* Re-association barriers around constants and other re-association
8039 barriers can be removed. */
8052 /* If we have (type) (a CMP b) and type is an integral type, return
8053 new expression involving the new type. */
8058 /* Handle cases of two conversions in a row. */
8061 {
8083 /* In addition to the cases of two conversions in a row
8084 handled below, if we are converting something to its own
8085 type via an object of identical or wider precision, neither
8086 conversion is needed. */
8093 /* Likewise, if the intermediate and final types are either both
8094 float or both integer, we don't need the middle conversion if
8095 it is wider than the final type and doesn't change the signedness
8096 (for integers). Avoid this if the final type is a pointer
8097 since then we sometimes need the inner conversion. Likewise if
8098 the outer has a precision not equal to the size of its mode. */
8107 && ! final_ptr
8111 /* If we have a sign-extension of a zero-extended value, we can
8112 replace that by a single zero-extension. */
8118 /* Two conversions in a row are not needed unless:
8119 - some conversion is floating-point (overstrict for now), or
8120 - some conversion is a vector (overstrict for now), or
8121 - the intermediate type is narrower than both initial and
8122 final, or
8123 - the intermediate type and innermost type differ in signedness,
8124 and the outermost type is wider than the intermediate, or
8125 - the initial type is a pointer type and the precisions of the
8126 intermediate and final types differ, or
8127 - the final type is a pointer type and the precisions of the
8128 initial and intermediate types differ.
8129 - the initial type is a pointer to an array and the final type
8130 not. */
8147 }
8149 /* Handle (T *)&A.B.C for A being of type T and B and C
8150 living at offset zero. This occurs frequently in
8151 C++ upcasting and then accessing the base. */
8155 {
8157 tree offset;
8163 /* If the reference was to a (constant) zero offset, we can use
8164 the address of the base if it has the same base type
8165 as the result type. */
8170 }
8175 /* Detect assigning a bitfield. */
8177 && DECL_BIT_FIELD
8179 {
8180 /* Don't leave an assignment inside a conversion
8181 unless assigning a bitfield. */
8183 /* First do the assignment, then return converted constant. */
8188 }
8190 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
8191 constants (if x has signed type, the sign bit cannot be set
8192 in c). This folds extension into the BIT_AND_EXPR. */
8197 {
8207 <= HOST_BITS_PER_WIDE_INT
8209 {
8216 #ifdef LOAD_EXTEND_OP
8218 && !flag_syntax_only
8221 {
8225 }
8226 #endif
8227 }
8229 {
8235 }
8236 }
8238 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
8239 when one of the new casts will fold away. Conservatively we assume
8240 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
8246 {
8252 }
8254 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
8255 of the same precision, and X is an integer type not narrower than
8256 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
8263 {
8268 }
8300 /* Convert fabs((double)float) into (double)fabsf(float). */
8303 {
8308 targ0));
8309 }
8310 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8316 /* Strip sign ops from argument. */
8318 {
8322 }
8329 {
8334 }
8336 {
8341 }
8351 /* Convert ~ (-A) to A - 1. */
8356 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8364 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8377 /* Perform BIT_NOT_EXPR on each element individually. */
8379 {
8384 {
8386 {
8392 }
8393 else
8396 }
8399 }
8404 /* The argument to invert_truthvalue must have Boolean type. */
8408 /* Note that the operand of this must be an int
8409 and its values must be 0 or 1.
8410 ("true" is a fixed value perhaps depending on the language,
8411 but we don't handle values other than 1 correctly yet.) */
8426 {
8434 }
8436 {
8440 }
8442 {
8446 {
8455 }
8456 }
8468 {
8476 }
8478 {
8482 }
8484 {
8488 {
8497 }
8498 }
8504 }
8506 /* Fold a binary expression of code CODE and type TYPE with operands
8507 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8508 Return the folded expression if folding is successful. Otherwise,
8509 return NULL_TREE. */
8511 static tree
8513 {
8520 else
8523 /* MIN (MAX (a, b), b) == b. */
8528 /* MIN (MAX (b, a), b) == b. */
8534 /* MIN (a, MAX (a, b)) == a. */
8540 /* MIN (a, MAX (b, a)) == a. */
8547 }
8549 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8550 by changing CODE to reduce the magnitude of constants involved in
8551 ARG0 of the comparison.
8552 Returns a canonicalized comparison tree if a simplification was
8553 possible, otherwise returns NULL_TREE.
8554 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8555 valid if signed overflow is undefined. */
8557 static tree
8561 {
8567 /* Match A +- CST code arg1 and CST code arg1. */
8574 /* Identify the constant in arg0 and its sign. */
8577 else
8581 /* Overflowed constants and zero will cause problems. */
8586 /* See if we can reduce the magnitude of the constant in
8587 arg0 by changing the comparison code. */
8589 {
8590 /* CST <= arg1 -> CST-1 < arg1. */
8593 /* -CST < arg1 -> -CST-1 <= arg1. */
8596 /* CST > arg1 -> CST-1 >= arg1. */
8599 /* -CST >= arg1 -> -CST-1 > arg1. */
8602 else
8604 /* arg1 code' CST' might be more canonical. */
8606 }
8607 else
8608 {
8609 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8613 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8617 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8621 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8625 else
8628 }
8630 /* Now build the constant reduced in magnitude. */
8636 /* If swapping might yield to a more canonical form, do so. */
8639 else
8641 }
8643 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8644 overflow further. Try to decrease the magnitude of constants involved
8645 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8646 and put sole constants at the second argument position.
8647 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8649 static tree
8652 {
8653 tree t;
8658 /* In principle pointers also have undefined overflow behavior,
8659 but that causes problems elsewhere. */
8664 /* Try canonicalization by simplifying arg0. */
8669 {
8673 }
8675 /* Try canonicalization by simplifying arg1 using the swapped
8676 comparison. */
8684 }
8686 /* Subroutine of fold_binary. This routine performs all of the
8687 transformations that are common to the equality/inequality
8688 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8689 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8690 fold_binary should call fold_binary. Fold a comparison with
8691 tree code CODE and type TYPE with operands OP0 and OP1. Return
8692 the folded comparison or NULL_TREE. */
8694 static tree
8696 {
8709 /* If one arg is a real or integer constant, put it last. */
8713 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8720 {
8724 tree lhs;
8731 /* If the constant operation overflowed this can be
8732 simplified as a comparison against INT_MAX/INT_MIN. */
8735 {
8739 /* Get the sign of the constant on the lhs if the
8740 operation were VARIABLE + CONST1. */
8744 /* The sign of the constant determines if we overflowed
8745 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8746 Canonicalize to the INT_MIN overflow by swapping the comparison
8747 if necessary. */
8751 /* We now can look at the canonicalized case
8752 VARIABLE + 1 CODE2 INT_MIN
8753 and decide on the result. */
8762 }
8767 {
8769 "when changing X +- C1 cmp C2 to "
8771 WARN_STRICT_OVERFLOW_COMPARISON);
8773 }
8774 }
8776 /* For comparisons of pointers we can decompose it to a compile time
8777 comparison of the base objects and the offsets into the object.
8778 This requires at least one operand being an ADDR_EXPR or a
8779 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8785 {
8792 /* Get base and offset for the access. Strip ADDR_EXPR for
8793 get_inner_reference, but put it back by stripping INDIRECT_REF
8794 off the base object if possible. */
8797 {
8803 else
8805 }
8807 {
8810 }
8814 {
8818 /* We have to make sure to have an indirect/non-indirect base1
8819 just the same as we did for base0. */
8825 }
8827 {
8830 }
8834 /* If we have equivalent bases we might be able to simplify. */
8837 {
8838 /* We can fold this expression to a constant if the non-constant
8839 offset parts are equal. */
8843 {
8845 {
8859 }
8860 }
8861 /* We can simplify the comparison to a comparison of the variable
8862 offset parts if the constant offset parts are equal.
8863 Be careful to use signed size type here because otherwise we
8864 mess with array offsets in the wrong way. This is possible
8865 because pointer arithmetic is restricted to retain within an
8866 object and overflow on pointer differences is undefined as of
8867 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8869 {
8870 tree signed_size_type_node;
8873 /* By converting to signed size type we cover middle-end pointer
8874 arithmetic which operates on unsigned pointer types of size
8875 type size and ARRAY_REF offsets which are properly sign or
8876 zero extended from their type in case it is narrower than
8877 size type. */
8880 else
8884 else
8888 }
8889 }
8890 }
8892 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8893 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8894 the resulting offset is smaller in absolute value than the
8895 original one. */
8903 {
8908 tree cst;
8910 "occur when combining constants around "
8913 /* Put the constant on the side where it doesn't overflow and is
8914 of lower absolute value than before. */
8920 {
8923 variable1,
8926 }
8933 {
8938 variable2);
8939 }
8940 }
8942 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8943 signed arithmetic case. That form is created by the compiler
8944 often enough for folding it to be of value. One example is in
8945 computing loop trip counts after Operator Strength Reduction. */
8951 {
8960 "eliminating multiplication in comparison "
8962 WARN_STRICT_OVERFLOW_COMPARISON);
8964 /* If const1 is negative we swap the sense of the comparison. */
8969 }
8976 {
8984 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8989 /* (-a) CMP (-b) -> b CMP a */
8996 {
8997 REAL_VALUE_TYPE cst;
9000 /* (-a) CMP CST -> a swap(CMP) (-CST) */
9007 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
9008 /* a CMP (-0) -> a CMP 0 */
9013 /* x != NaN is always true, other ops are always false. */
9016 {
9019 }
9021 /* Fold comparisons against infinity. */
9023 {
9027 }
9028 }
9030 /* If this is a comparison of a real constant with a PLUS_EXPR
9031 or a MINUS_EXPR of a real constant, we can convert it into a
9032 comparison with a revised real constant as long as no overflow
9033 occurs when unsafe_math_optimizations are enabled. */
9045 /* Likewise, we can simplify a comparison of a real constant with
9046 a MINUS_EXPR whose first operand is also a real constant, i.e.
9047 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9048 floating-point types only if -fassociative-math is set. */
9059 /* Fold comparisons against built-in math functions. */
9061 && flag_unsafe_math_optimizations
9063 {
9067 {
9071 }
9072 }
9073 }
9078 {
9079 /* If we are widening one operand of an integer comparison,
9080 see if the other operand is similarly being widened. Perhaps we
9081 can do the comparison in the narrower type. */
9086 /* Or if we are changing signedness. */
9090 }
9092 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9093 constant, we can simplify it. */
9098 {
9102 }
9104 /* Simplify comparison of something with itself. (For IEEE
9105 floating-point, we can only do some of these simplifications.) */
9107 {
9109 {
9124 /* For NE, we can only do this simplification if integer
9125 or we don't honor IEEE floating point NaNs. */
9129 /* ... fall through ... */
9135 }
9136 }
9138 /* If we are comparing an expression that just has comparisons
9139 of two integer values, arithmetic expressions of those comparisons,
9140 and constants, we can simplify it. There are only three cases
9141 to check: the two values can either be equal, the first can be
9142 greater, or the second can be greater. Fold the expression for
9143 those three values. Since each value must be 0 or 1, we have
9144 eight possibilities, each of which corresponds to the constant 0
9145 or 1 or one of the six possible comparisons.
9147 This handles common cases like (a > b) == 0 but also handles
9148 expressions like ((x > y) - (y > x)) > 0, which supposedly
9149 occur in macroized code. */
9152 {
9157 /* Don't handle degenerate cases here; they should already
9158 have been handled anyway. */
9167 {
9171 /* We can't just pass T to eval_subst in case cval1 or cval2
9172 was the same as ARG1. */
9174 tree high_result
9178 arg1);
9179 tree equal_result
9183 arg1);
9184 tree low_result
9188 arg1);
9190 /* All three of these results should be 0 or 1. Confirm they are.
9191 Then use those values to select the proper code to use. */
9196 {
9197 /* Make a 3-bit mask with the high-order bit being the
9198 value for `>', the next for '=', and the low for '<'. */
9202 {
9204 /* Always false. */
9225 /* Always true. */
9227 }
9232 }
9233 }
9234 }
9236 /* Fold a comparison of the address of COMPONENT_REFs with the same
9237 type and component to a comparison of the address of the base
9238 object. In short, &x->a OP &y->a to x OP y and
9239 &x->a OP &y.a to x OP &y */
9244 {
9248 {
9254 }
9255 }
9257 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9258 into a single range test. */
9266 {
9270 }
9272 /* Fold ~X op ~Y as Y op X. */
9275 {
9280 }
9282 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9285 {
9291 }
9294 }
9297 /* Subroutine of fold_binary. Optimize complex multiplications of the
9298 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9299 argument EXPR represents the expression "z" of type TYPE. */
9301 static tree
9303 {
9308 {
9311 }
9313 {
9316 }
9317 else
9318 {
9322 }
9331 }
9334 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9335 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9336 guarantees that P and N have the same least significant log2(M) bits.
9337 N is not otherwise constrained. In particular, N is not normalized to
9338 0 <= N < M as is common. In general, the precise value of P is unknown.
9339 M is chosen as large as possible such that constant N can be determined.
9341 Returns M and sets *RESIDUE to N. */
9343 static unsigned HOST_WIDE_INT
9345 {
9352 {
9355 {
9357 tree offset;
9365 {
9368 else
9369 /* We don't handle more complicated offset expressions. */
9371 }
9372 }
9376 }
9378 {
9391 {
9394 }
9396 {
9399 {
9402 /* Compute the greatest power-of-2 divisor of op1. */
9406 /* If align is non-zero and less than *modulus, replace
9407 *modulus with align., If align is 0, then either op1 is 0
9408 or the greatest power-of-2 divisor of op1 doesn't fit in an
9409 unsigned HOST_WIDE_INT. In either case, no additional
9410 constraint is imposed. */
9415 }
9416 }
9417 }
9419 /* If we get here, we were unable to determine anything useful about the
9420 expression. */
9422 }
9425 /* Fold a binary expression of code CODE and type TYPE with operands
9426 OP0 and OP1. Return the folded expression if folding is
9427 successful. Otherwise, return NULL_TREE. */
9429 tree
9431 {
9446 /* Strip any conversions that don't change the mode. This is
9447 safe for every expression, except for a comparison expression
9448 because its signedness is derived from its operands. So, in
9449 the latter case, only strip conversions that don't change the
9450 signedness.
9452 Note that this is done as an internal manipulation within the
9453 constant folder, in order to find the simplest representation
9454 of the arguments so that their form can be studied. In any
9455 cases, the appropriate type conversions should be put back in
9456 the tree that will get out of the constant folder. */
9459 {
9462 }
9463 else
9464 {
9467 }
9469 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9470 constant but we can't do arithmetic on them. */
9477 {
9479 {
9480 /* Make sure type and arg0 have the same saturating flag. */
9484 }
9487 else
9491 {
9495 }
9496 }
9498 /* If this is a commutative operation, and ARG0 is a constant, move it
9499 to ARG1 to reduce the number of tests below. */
9504 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9506 First check for cases where an arithmetic operation is applied to a
9507 compound, conditional, or comparison operation. Push the arithmetic
9508 operation inside the compound or conditional to see if any folding
9509 can then be done. Convert comparison to conditional for this purpose.
9510 The also optimizes non-constant cases that used to be done in
9511 expand_expr.
9513 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9514 one of the operands is a comparison and the other is a comparison, a
9515 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9516 code below would make the expression more complex. Change it to a
9517 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9518 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9530 {
9534 boolean_type_node,
9542 }
9546 {
9552 op1));
9561 {
9567 }
9570 {
9576 }
9577 }
9580 {
9582 /* 0 +p index -> (type)index */
9586 /* PTR +p 0 -> PTR */
9590 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9597 /* index +p PTR -> PTR +p index */
9604 /* (PTR +p B) +p A -> PTR +p (B + A) */
9606 {
9607 tree inner;
9615 }
9617 /* PTR_CST +p CST -> CST1 */
9621 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9622 of the array. Loop optimizer sometimes produce this type of
9623 expressions. */
9625 {
9629 }
9634 /* PTR + INT -> (INT)(PTR p+ INT) */
9639 arg0,
9641 /* INT + PTR -> (INT)(PTR p+ INT) */
9646 arg1,
9648 /* A + (-B) -> A - B */
9653 /* (-A) + B -> B - A */
9661 {
9662 /* Convert ~A + 1 to -A. */
9667 /* ~X + X is -1. */
9670 {
9675 {
9678 }
9679 }
9681 /* X + ~X is -1. */
9684 {
9689 {
9692 }
9693 }
9695 /* X + (X / CST) * -CST is X % CST. */
9700 {
9708 }
9709 }
9711 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9712 same or one. Make sure type is not saturating.
9713 fold_plusminus_mult_expr will re-associate. */
9718 {
9722 }
9725 {
9729 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9730 with a constant, and the two constants have no bits in common,
9731 we should treat this as a BIT_IOR_EXPR since this may produce more
9732 simplifications. */
9740 {
9743 }
9745 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9746 (plus (plus (mult) (mult)) (foo)) so that we can
9747 take advantage of the factoring cases below. */
9754 {
9760 else
9782 parg1)));
9783 }
9784 }
9785 else
9786 {
9787 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9791 /* Likewise if the operands are reversed. */
9795 /* Convert X + -C into X - C. */
9798 {
9804 }
9806 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9807 to __complex__ ( x, y ). This is not the same for SNaNs or
9808 if signed zeros are involved. */
9812 {
9819 {
9823 {
9829 }
9831 {
9837 }
9838 }
9839 }
9847 /* Convert x+x into x*2.0. */
9853 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9854 We associate floats only if the user has specified
9855 -fassociative-math. */
9859 {
9864 {
9865 tree tree0;
9868 }
9869 }
9870 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9871 We associate floats only if the user has specified
9872 -fassociative-math. */
9876 {
9881 {
9882 tree tree0;
9885 }
9886 }
9887 }
9889 bit_rotate:
9890 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9891 is a rotate of A by C1 bits. */
9892 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9893 is a rotate of A by B bits. */
9894 {
9896 tree rtype;
9905 /* Only create rotates in complete modes. Other cases are not
9906 expanded properly. */
9908 {
9927 {
9935 TYPE_PRECISION
9940 ? LROTATE_EXPR
9943 }
9945 {
9953 TYPE_PRECISION
9958 ? LROTATE_EXPR
9961 }
9962 }
9963 }
9965 associate:
9966 /* In most languages, can't associate operations on floats through
9967 parentheses. Rather than remember where the parentheses were, we
9968 don't associate floats at all, unless the user has specified
9969 -fassociative-math.
9970 And, we need to make sure type is not saturating. */
9974 {
9979 /* Split both trees into variables, constants, and literals. Then
9980 associate each group together, the constants with literals,
9981 then the result with variables. This increases the chances of
9982 literals being recombined later and of generating relocatable
9983 expressions for the sum of a constant and literal. */
9988 /* With undefined overflow we can only associate constants
9989 with one variable. */
9993 {
10001 /* The only case we can still associate with two variables
10002 is if they are the same, modulo negation. */
10005 }
10007 /* Only do something if we found more than two objects. Otherwise,
10008 nothing has changed and we risk infinite recursion. */
10014 {
10015 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10024 /* Preserve the MINUS_EXPR if the negative part of the literal is
10025 greater than the positive part. Otherwise, the multiplicative
10026 folding code (i.e extract_muldiv) may be fooled in case
10027 unsigned constants are subtracted, like in the following
10028 example: ((X*2 + 4) - 8U)/2. */
10030 {
10034 {
10038 }
10039 else
10040 {
10044 }
10045 }
10047 {
10052 else
10053 {
10059 }
10060 }
10065 }
10066 }
10071 /* Pointer simplifications for subtraction, simple reassociations. */
10073 {
10074 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10077 {
10085 }
10086 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10088 {
10094 }
10095 }
10096 /* A - (-B) -> A + B */
10100 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10109 /* Convert -A - 1 to ~A. */
10117 /* Convert -1 - A to ~A. */
10123 /* X - (X / CST) * CST is X % CST. */
10136 {
10142 /* Fold A - (A & B) into ~B & A. */
10145 {
10147 {
10152 }
10154 {
10159 }
10160 }
10162 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10163 any power of 2 minus 1. */
10168 {
10174 {
10178 }
10179 }
10180 }
10182 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10186 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10187 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10188 (-ARG1 + ARG0) reduces to -ARG1. */
10192 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10193 __complex__ ( x, -y ). This is not the same for SNaNs or if
10194 signed zeros are involved. */
10198 {
10205 {
10209 {
10211 arg1r ? arg1r
10216 }
10218 {
10222 arg1i ? arg1i
10225 }
10226 }
10227 }
10229 /* Fold &x - &x. This can happen from &x.foo - &x.
10230 This is unsafe for certain floats even in non-IEEE formats.
10231 In IEEE, it is unsafe because it does wrong for NaNs.
10232 Also note that operand_equal_p is always false if an operand
10233 is volatile. */
10239 /* A - B -> A + (-B) if B is easily negatable. */
10242 /* Avoid this transformation if B is a positive REAL_CST. */
10250 /* Try folding difference of addresses. */
10251 {
10252 HOST_WIDE_INT diff;
10258 }
10260 /* Fold &a[i] - &a[j] to i-j. */
10265 {
10270 {
10278 }
10279 }
10287 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10288 same or one. Make sure type is not saturating.
10289 fold_plusminus_mult_expr will re-associate. */
10294 {
10298 }
10303 /* (-A) * (-B) -> A * B */
10314 {
10319 /* Transform x * -1 into -x. Make sure to do the negation
10320 on the original operand with conversions not stripped
10321 because we can only strip non-sign-changing conversions. */
10324 /* Transform x * -C into -x * C if x is easily negatable. */
10333 /* (a * (1 << b)) is (a << b) */
10347 {
10350 "occur when simplifying "
10352 WARN_STRICT_OVERFLOW_MISC);
10354 }
10356 /* Optimize z * conj(z) for integer complex numbers. */
10363 }
10364 else
10365 {
10366 /* Maybe fold x * 0 to 0. The expressions aren't the same
10367 when x is NaN, since x * 0 is also NaN. Nor are they the
10368 same in modes with signed zeros, since multiplying a
10369 negative value by 0 gives -0, not +0. */
10374 /* In IEEE floating point, x*1 is not equivalent to x for snans. */
10379 /* Transform x * -1.0 into -x. */
10384 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10385 the result for floating point types due to rounding so it is applied
10386 only if -fassociative-math was specify. */
10391 {
10397 }
10399 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10401 {
10404 {
10407 }
10408 }
10410 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10411 This is not the same for NaNs or if signed zeros are
10412 involved. */
10418 {
10430 }
10432 /* Optimize z * conj(z) for floating point complex numbers.
10433 Guarded by flag_unsafe_math_optimizations as non-finite
10434 imaginary components don't produce scalar results. */
10445 {
10449 /* Optimizations of root(...)*root(...). */
10451 {
10456 /* Optimize sqrt(x)*sqrt(x) as x. */
10462 /* Optimize root(x)*root(y) as root(x*y). */
10466 }
10468 /* Optimize expN(x)*expN(y) as expN(x+y). */
10470 {
10476 }
10478 /* Optimizations of pow(...)*pow(...). */
10482 {
10488 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10490 {
10494 }
10496 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10498 {
10502 }
10503 }
10505 /* Optimize tan(x)*cos(x) as sin(x). */
10514 {
10519 }
10521 /* Optimize x*pow(x,c) as pow(x,c+1). */
10525 {
10531 {
10533 REAL_VALUE_TYPE c;
10534 tree arg;
10540 }
10541 }
10543 /* Optimize pow(x,c)*x as pow(x,c+1). */
10547 {
10553 {
10555 REAL_VALUE_TYPE c;
10556 tree arg;
10562 }
10563 }
10565 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10568 {
10572 {
10575 }
10576 }
10577 }
10578 }
10582 bit_ior:
10590 /* ~X | X is -1. */
10593 {
10597 }
10599 /* X | ~X is -1. */
10602 {
10606 }
10608 /* Canonicalize (X & C1) | C2. */
10612 {
10620 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10625 {
10629 }
10630 else
10631 {
10635 }
10637 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10642 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10643 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10644 mode which allows further optimizations. */
10654 {
10655 unsigned HOST_WIDE_INT mask
10659 {
10663 }
10664 }
10671 arg1);
10672 }
10674 /* (X & Y) | Y is (X, Y). */
10678 /* (X & Y) | X is (Y, X). */
10683 /* X | (X & Y) is (Y, X). */
10688 /* X | (Y & X) is (Y, X). */
10698 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10700 This results in more efficient code for machines without a NAND
10701 instruction. Combine will canonicalize to the first form
10702 which will allow use of NAND instructions provided by the
10703 backend if they exist. */
10706 {
10711 }
10713 /* See if this can be simplified into a rotate first. If that
10714 is unsuccessful continue in the association code. */
10725 /* ~X ^ X is -1. */
10728 {
10732 }
10734 /* X ^ ~X is -1. */
10737 {
10741 }
10743 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10744 with a constant, and the two constants have no bits in common,
10745 we should treat this as a BIT_IOR_EXPR since this may produce more
10746 simplifications. */
10754 {
10757 }
10759 /* (X | Y) ^ X -> Y & ~ X*/
10762 {
10765 arg1);
10769 }
10771 /* (Y | X) ^ X -> Y & ~ X*/
10774 {
10777 arg1);
10781 }
10783 /* X ^ (X | Y) -> Y & ~ X*/
10786 {
10789 arg0);
10793 }
10795 /* X ^ (Y | X) -> Y & ~ X*/
10798 {
10801 arg0);
10805 }
10807 /* Convert ~X ^ ~Y to X ^ Y. */
10814 /* Convert ~X ^ C to X ^ ~C. */
10821 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10828 /* Fold (X & Y) ^ Y as ~X & Y. */
10831 {
10836 }
10837 /* Fold (X & Y) ^ X as ~Y & X. */
10841 {
10846 }
10847 /* Fold X ^ (X & Y) as X & ~Y. */
10850 {
10855 }
10856 /* Fold X ^ (Y & X) as ~Y & X. */
10860 {
10865 }
10867 /* See if this can be simplified into a rotate first. If that
10868 is unsuccessful continue in the association code. */
10879 /* ~X & X is always zero. */
10884 /* X & ~X is always zero. */
10889 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10893 {
10902 }
10904 /* (X | Y) & Y is (X, Y). */
10908 /* (X | Y) & X is (Y, X). */
10913 /* X & (X | Y) is (Y, X). */
10918 /* X & (Y | X) is (Y, X). */
10924 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10928 {
10934 }
10935 /* Fold ~X & 1 as (X & 1) == 0. */
10938 {
10944 }
10946 /* Fold (X ^ Y) & Y as ~X & Y. */
10949 {
10954 }
10955 /* Fold (X ^ Y) & X as ~Y & X. */
10959 {
10964 }
10965 /* Fold X & (X ^ Y) as X & ~Y. */
10968 {
10973 }
10974 /* Fold X & (Y ^ X) as ~Y & X. */
10978 {
10983 }
10988 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10991 {
10992 unsigned int prec
10999 }
11001 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
11003 This results in more efficient code for machines without a NOR
11004 instruction. Combine will canonicalize to the first form
11005 which will allow use of NOR instructions provided by the
11006 backend if they exist. */
11009 {
11016 }
11018 /* If arg0 is derived from the address of an object or function, we may
11019 be able to fold this expression using the object or function's
11020 alignment. */
11022 {
11028 /* This works because modulus is a power of 2. If this weren't the
11029 case, we'd have to replace it by its greatest power-of-2
11030 divisor: modulus & -modulus. */
11033 }
11035 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
11036 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
11037 if the new mask might be further optimized. */
11046 {
11048 unsigned HOST_WIDE_INT mask
11058 {
11061 /* See if more bits can be proven as zero because of
11062 zero extension. */
11065 {
11070 {
11072 /* See if we can shorten the right shift. */
11075 }
11076 }
11080 /* For arithmetic shift if sign bit could be set, zerobits
11081 can contain actually sign bits, so no transformation is
11082 possible, unless MASK masks them all away. In that
11083 case the shift needs to be converted into logical shift. */
11086 {
11089 else
11091 }
11092 }
11094 /* ((X << 16) & 0xff00) is (X, 0). */
11100 {
11103 /* Only do the transformation if NEWMASK is some integer
11104 mode's mask. */
11111 {
11113 {
11119 }
11120 else
11124 newmask));
11125 }
11126 }
11127 }
11132 /* Don't touch a floating-point divide by zero unless the mode
11133 of the constant can represent infinity. */
11139 /* Optimize A / A to 1.0 if we don't care about
11140 NaNs or Infinities. Skip the transformation
11141 for non-real operands. */
11146 {
11150 }
11152 /* The complex version of the above A / A optimization. */
11155 {
11159 {
11161 /* omit_two_operands will call fold_convert for us. */
11163 }
11164 }
11166 /* (-A) / (-B) -> A / B */
11176 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11181 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11186 /* If ARG1 is a constant, we can convert this to a multiply by the
11187 reciprocal. This does not have the same rounding properties,
11188 so only do this if -freciprocal-math. We can actually
11189 always safely do it if ARG1 is a power of two, but it's hard to
11190 tell if it is or not in a portable manner. */
11192 {
11197 /* Find the reciprocal if optimizing and the result is exact. */
11199 {
11200 REAL_VALUE_TYPE r;
11203 {
11207 }
11208 }
11209 }
11210 /* Convert A/B/C to A/(B*C). */
11217 /* Convert A/(B/C) to (A/B)*C. */
11225 /* Convert C1/(X*C2) into (C1/C2)/X. */
11230 {
11236 }
11239 {
11243 /* Optimize sin(x)/cos(x) as tan(x). */
11249 {
11254 }
11256 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11262 {
11266 {
11270 }
11271 }
11273 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11274 NaNs or Infinities. */
11278 {
11285 {
11290 }
11291 }
11293 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11294 NaNs or Infinities. */
11298 {
11305 {
11309 {
11313 tmp);
11314 }
11315 }
11316 }
11318 /* Optimize pow(x,c)/x as pow(x,c-1). */
11322 {
11328 {
11330 REAL_VALUE_TYPE c;
11331 tree arg;
11337 }
11338 }
11340 /* Optimize a/root(b/c) into a*root(c/b). */
11342 {
11346 {
11355 }
11356 }
11358 /* Optimize x/expN(y) into x*expN(-y). */
11360 {
11365 }
11367 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11371 {
11378 }
11379 }
11384 /* Simplify A / (B << N) where A and B are positive and B is
11385 a power of 2, to A >> (N + log2(B)). */
11390 {
11393 {
11400 WARN_STRICT_OVERFLOW_MISC);
11406 }
11407 }
11409 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11410 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11416 /* Fall thru */
11425 /* X / -1 is -X. */
11432 /* Convert -A / -B to A / B when the type is signed and overflow is
11433 undefined. */
11437 {
11440 "when distributing negation across "
11442 WARN_STRICT_OVERFLOW_MISC);
11446 }
11450 {
11453 "when distributing negation across "
11455 WARN_STRICT_OVERFLOW_MISC);
11458 }
11460 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11461 operation, EXACT_DIV_EXPR.
11463 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11464 At one time others generated faster code, it's not clear if they do
11465 after the last round to changes to the DIV code in expmed.c. */
11474 {
11478 WARN_STRICT_OVERFLOW_MISC);
11480 }
11488 /* X % 1 is always zero, but be sure to preserve any side
11489 effects in X. */
11493 /* X % 0, return X % 0 unchanged so that we can get the
11494 proper warnings and errors. */
11498 /* 0 % X is always zero, but be sure to preserve any side
11499 effects in X. Place this after checking for X == 0. */
11503 /* X % -1 is zero. */
11510 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11511 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11516 {
11518 /* Also optimize A % (C << N) where C is a power of 2,
11519 to A & ((C << N) - 1). */
11524 {
11529 "occur when simplifying "
11531 WARN_STRICT_OVERFLOW_MISC);
11535 }
11536 }
11538 /* X % -C is the same as X % C. */
11545 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11550 /* X % -Y is the same as X % Y. */
11561 {
11565 WARN_STRICT_OVERFLOW_MISC);
11567 }
11578 /* Optimize -1 >> x for arithmetic right shifts. */
11581 /* ... fall through ... */
11584 shift:
11590 /* Since negative shift count is not well-defined,
11591 don't try to compute it in the compiler. */
11595 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11600 {
11604 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11605 being well defined. */
11607 {
11612 else
11614 }
11618 }
11620 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11621 into x & ((unsigned)-1 >> c) for unsigned types. */
11629 {
11632 tree lshift;
11633 tree arg00;
11636 {
11643 }
11644 }
11646 /* Rewrite an LROTATE_EXPR by a constant into an
11647 RROTATE_EXPR by a new constant. */
11649 {
11654 }
11656 /* If we have a rotate of a bit operation with the rotate count and
11657 the second operand of the bit operation both constant,
11658 permute the two operations. */
11670 /* Two consecutive rotates adding up to the precision of the
11671 type can be ignored. */
11682 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11683 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11684 if the latter can be further optimized. */
11689 {
11692 arg1);
11695 arg1);
11699 }
11727 /* Note that the operands of this must be ints
11728 and their values must be 0 or 1.
11729 ("true" is a fixed value perhaps depending on the language.) */
11730 /* If first arg is constant zero, return it. */
11734 /* If either arg is constant true, drop it. */
11738 /* Preserve sequence points. */
11741 /* If second arg is constant zero, result is zero, but first arg
11742 must be evaluated. */
11745 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11746 case will be handled here. */
11750 /* !X && X is always false. */
11754 /* X && !X is always false. */
11759 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11760 means A >= Y && A != MAX, but in this case we know that
11761 A < X <= MAX. */
11765 {
11773 }
11775 truth_andor:
11776 /* We only do these simplifications if we are optimizing. */
11780 /* Check for things like (A || B) && (A || C). We can convert this
11781 to A || (B && C). Note that either operator can be any of the four
11782 truth and/or operations and the transformation will still be
11783 valid. Also note that we only care about order for the
11784 ANDIF and ORIF operators. If B contains side effects, this
11785 might change the truth-value of A. */
11792 {
11812 /* This case if tricky because we must either have commutative
11813 operators or else A10 must not have side-effects. */
11819 a01);
11820 }
11822 /* See if we can build a range comparison. */
11826 /* Check for the possibility of merging component references. If our
11827 lhs is another similar operation, try to merge its rhs with our
11828 rhs. Then try to merge our lhs and rhs. */
11840 /* Note that the operands of this must be ints
11841 and their values must be 0 or true.
11842 ("true" is a fixed value perhaps depending on the language.) */
11843 /* If first arg is constant true, return it. */
11847 /* If either arg is constant zero, drop it. */
11851 /* Preserve sequence points. */
11854 /* If second arg is constant true, result is true, but we must
11855 evaluate first arg. */
11858 /* Likewise for first arg, but note this only occurs here for
11859 TRUTH_OR_EXPR. */
11863 /* !X || X is always true. */
11867 /* X || !X is always true. */
11875 /* If the second arg is constant zero, drop it. */
11878 /* If the second arg is constant true, this is a logical inversion. */
11880 {
11881 /* Only call invert_truthvalue if operand is a truth value. */
11884 else
11887 }
11888 /* Identical arguments cancel to zero. */
11892 /* !X ^ X is always true. */
11897 /* X ^ !X is always true. */
11910 /* bool_var != 0 becomes bool_var. */
11915 /* bool_var == 1 becomes bool_var. */
11920 /* bool_var != 1 becomes !bool_var. */
11925 /* bool_var == 0 becomes !bool_var. */
11930 /* If this is an equality comparison of the address of two non-weak,
11931 unaliased symbols neither of which are extern (since we do not
11932 have access to attributes for externs), then we know the result. */
11945 {
11946 /* We know that we're looking at the address of two
11947 non-weak, unaliased, static _DECL nodes.
11949 It is both wasteful and incorrect to call operand_equal_p
11950 to compare the two ADDR_EXPR nodes. It is wasteful in that
11951 all we need to do is test pointer equality for the arguments
11952 to the two ADDR_EXPR nodes. It is incorrect to use
11953 operand_equal_p as that function is NOT equivalent to a
11954 C equality test. It can in fact return false for two
11955 objects which would test as equal using the C equality
11956 operator. */
11960 type);
11961 }
11963 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11964 a MINUS_EXPR of a constant, we can convert it into a comparison with
11965 a revised constant as long as no overflow occurs. */
11977 /* Similarly for a NEGATE_EXPR. */
11985 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11994 /* Transform comparisons of the form X +- C CMP X. */
12000 {
12007 else
12010 }
12012 /* If we have X - Y == 0, we can convert that to X == Y and similarly
12013 for !=. Don't do this for ordered comparisons due to overflow. */
12019 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
12024 /* If this is an EQ or NE comparison with zero and ARG0 is
12025 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12026 two operations, but the latter can be done in one less insn
12027 on machines that have only two-operand insns or on which a
12028 constant cannot be the first operand. */
12031 {
12036 {
12043 }
12046 {
12053 }
12054 }
12056 /* If this is an NE or EQ comparison of zero against the result of a
12057 signed MOD operation whose second operand is a power of 2, make
12058 the MOD operation unsigned since it is simpler and equivalent. */
12066 {
12076 }
12078 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12079 C1 is a valid shift constant, and C2 is a power of two, i.e.
12080 a single bit. */
12084 == INTEGER_CST
12087 {
12092 /* Check for a valid shift count. */
12095 {
12099 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12100 can be rewritten as (X & (C2 << C1)) != 0. */
12102 {
12106 }
12107 /* Otherwise, for signed (arithmetic) shifts,
12108 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12109 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12113 /* Otherwise, of unsigned (logical) shifts,
12114 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12115 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12116 else
12120 arg000);
12121 }
12122 }
12124 /* If this is an NE comparison of zero with an AND of one, remove the
12125 comparison since the AND will give the correct value. */
12132 /* If we have (A & C) == C where C is a power of 2, convert this into
12133 (A & C) != 0. Similarly for NE_EXPR. */
12139 integer_zero_node));
12141 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12142 bit, then fold the expression into A < 0 or A >= 0. */
12147 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12148 Similarly for NE_EXPR. */
12152 {
12161 }
12163 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12164 Similarly for NE_EXPR. */
12168 {
12175 }
12177 /* If this is a comparison of a field, we may be able to simplify it. */
12180 /* Handle the constant case even without -O
12181 to make sure the warnings are given. */
12183 {
12187 }
12189 /* Optimize comparisons of strlen vs zero to a compare of the
12190 first character of the string vs zero. To wit,
12191 strlen(ptr) == 0 => *ptr == 0
12192 strlen(ptr) != 0 => *ptr != 0
12193 Other cases should reduce to one of these two (or a constant)
12194 due to the return value of strlen being unsigned. */
12197 {
12205 {
12209 }
12210 }
12212 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12213 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12217 {
12224 {
12226 {
12229 }
12232 }
12233 }
12235 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12241 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12246 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12253 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12261 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12262 (X & C) == 0 when C is a single bit. */
12267 {
12273 }
12275 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12276 constant C is a power of two, i.e. a single bit. */
12283 {
12287 }
12289 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12290 when is C is a power of two, i.e. a single bit. */
12297 {
12303 }
12307 {
12310 }
12312 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12319 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12322 {
12334 arg01),
12342 arg01),
12350 arg00),
12358 arg00),
12360 }
12364 {
12371 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12372 operand_equal_p guarantees no side-effects so we don't need
12373 to use omit_one_operand on Z. */
12383 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12390 arg10);
12391 }
12393 /* Attempt to simplify equality/inequality comparisons of complex
12394 values. Only lower the comparison if the result is known or
12395 can be simplified to a single scalar comparison. */
12400 {
12405 {
12408 }
12409 else
12410 {
12413 }
12416 {
12419 }
12420 else
12421 {
12424 }
12428 {
12430 {
12435 }
12436 else
12437 {
12442 }
12443 }
12447 {
12449 {
12454 }
12455 else
12456 {
12461 }
12462 }
12463 }
12475 /* Transform comparisons of the form X +- C CMP X. */
12482 {
12489 else
12492 /* (X - c) > X becomes false. */
12496 {
12500 "occur when assuming that (X - c) > X "
12502 WARN_STRICT_OVERFLOW_ALL);
12504 }
12506 /* Likewise (X + c) < X becomes false. */
12510 {
12514 "occur when assuming that "
12516 WARN_STRICT_OVERFLOW_ALL);
12518 }
12520 /* Convert (X - c) <= X to true. */
12525 {
12529 "occur when assuming that "
12531 WARN_STRICT_OVERFLOW_ALL);
12533 }
12535 /* Convert (X + c) >= X to true. */
12540 {
12544 "occur when assuming that "
12546 WARN_STRICT_OVERFLOW_ALL);
12548 }
12551 {
12552 /* Convert X + c > X and X - c < X to true for integers. */
12556 {
12559 "not occur when assuming that "
12561 WARN_STRICT_OVERFLOW_ALL);
12563 }
12568 {
12571 "not occur when assuming that "
12573 WARN_STRICT_OVERFLOW_ALL);
12575 }
12577 /* Convert X + c <= X and X - c >= X to false for integers. */
12581 {
12584 "not occur when assuming that "
12586 WARN_STRICT_OVERFLOW_ALL);
12588 }
12593 {
12596 "not occur when assuming that "
12598 WARN_STRICT_OVERFLOW_ALL);
12600 }
12601 }
12602 }
12604 /* Change X >= C to X > (C - 1) and X < C to X <= (C - 1) if C > 0.
12605 This transformation affects the cases which are handled in later
12606 optimizations involving comparisons with non-negative constants. */
12610 {
12612 {
12617 }
12619 {
12624 }
12625 }
12627 /* Comparisons with the highest or lowest possible integer of
12628 the specified precision will have known values. */
12629 {
12637 {
12638 HOST_WIDE_INT signed_max_hi;
12643 {
12650 {
12654 }
12655 else
12656 {
12660 }
12661 }
12662 else
12663 {
12672 {
12675 }
12676 else
12677 {
12680 }
12681 }
12686 {
12699 /* The GE_EXPR and LT_EXPR cases above are not normally
12700 reached because of previous transformations. */
12704 }
12706 == max_hi
12709 {
12715 arg1);
12721 arg1);
12724 }
12726 == min_hi
12729 {
12744 }
12746 == min_hi
12749 {
12754 arg1);
12759 arg1);
12762 }
12767 /* We will flip the signedness of the comparison operator
12768 associated with the mode of arg1, so the sign bit is
12769 specified by this mode. Check that arg1 is the signed
12770 max associated with this sign bit. */
12772 /* signed_type does not work on pointer types. */
12774 {
12775 /* The following case also applies to X < signed_max+1
12776 and X >= signed_max+1 because previous transformations. */
12778 {
12779 tree st;
12784 }
12785 }
12786 }
12787 }
12789 /* If we are comparing an ABS_EXPR with a constant, we can
12790 convert all the cases into explicit comparisons, but they may
12791 well not be faster than doing the ABS and one comparison.
12792 But ABS (X) <= C is a range comparison, which becomes a subtraction
12793 and a comparison, and is probably faster. */
12807 /* Convert ABS_EXPR<x> >= 0 to true. */
12814 {
12817 "when simplifying comparison of "
12819 WARN_STRICT_OVERFLOW_CONDITIONAL);
12821 }
12823 /* Convert ABS_EXPR<x> < 0 to false. */
12828 {
12831 "when simplifying comparison of "
12833 WARN_STRICT_OVERFLOW_CONDITIONAL);
12835 }
12837 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12838 and similarly for >= into !=. */
12854 return
12873 {
12877 }
12879 /* If the first operand is NaN, the result is constant. */
12883 {
12885 ? integer_zero_node
12888 }
12890 /* If the second operand is NaN, the result is constant. */
12894 {
12896 ? integer_zero_node
12899 }
12901 /* Simplify unordered comparison of something with itself. */
12907 && !flag_trapping_math
12911 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12912 {
12923 }
12928 /* When pedantic, a compound expression can be neither an lvalue
12929 nor an integer constant expression. */
12932 /* Don't let (0, 0) be null pointer constant. */
12946 /* An ASSERT_EXPR should never be passed to fold_binary. */
12952 }
12954 /* Callback for walk_tree, looking for LABEL_EXPR.
12955 Returns tree TP if it is LABEL_EXPR. Otherwise it returns NULL_TREE.
12956 Do not check the sub-tree of GOTO_EXPR. */
12958 static tree
12962 {
12964 {
12969 /* no break */
12972 }
12973 }
12975 /* Checks whether the sub-tree ST contains a label LABEL_EXPR which is
12976 accessible from outside the sub-tree. Returns NULL_TREE if no
12977 addressable label is found. */
12979 static bool
12981 {
12983 }
12985 /* Fold a ternary expression of code CODE and type TYPE with operands
12986 OP0, OP1, and OP2. Return the folded expression if folding is
12987 successful. Otherwise, return NULL_TREE. */
12989 tree
12991 {
12992 tree tem;
12999 /* Strip any conversions that don't change the mode. This is safe
13000 for every expression, except for a comparison expression because
13001 its signedness is derived from its operands. So, in the latter
13002 case, only strip conversions that don't change the signedness.
13004 Note that this is done as an internal manipulation within the
13005 constant folder, in order to find the simplest representation of
13006 the arguments so that their form can be studied. In any cases,
13007 the appropriate type conversions should be put back in the tree
13008 that will get out of the constant folder. */
13010 {
13013 }
13016 {
13019 }
13022 {
13026 {
13032 }
13036 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
13037 so all simple results must be passed through pedantic_non_lvalue. */
13039 {
13042 /* Only optimize constant conditions when the selected branch
13043 has the same type as the COND_EXPR. This avoids optimizing
13044 away "c ? x : throw", where the throw has a void type.
13045 Avoid throwing away that operand which contains label. */
13052 }
13056 /* If we have A op B ? A : C, we may be able to convert this to a
13057 simpler expression, depending on the operation and the values
13058 of B and C. Signed zeros prevent all of these transformations,
13059 for reasons given above each one.
13061 Also try swapping the arguments and inverting the conditional. */
13066 {
13070 }
13074 op2,
13077 {
13080 {
13084 }
13085 }
13087 /* If the second operand is simpler than the third, swap them
13088 since that produces better jump optimization results. */
13091 {
13092 /* See if this can be inverted. If it can't, possibly because
13093 it was a floating-point inequality comparison, don't do
13094 anything. */
13098 }
13100 /* Convert A ? 1 : 0 to simply A. */
13103 /* If we try to convert OP0 to our type, the
13104 call to fold will try to move the conversion inside
13105 a COND, which will recurse. In that case, the COND_EXPR
13106 is probably the best choice, so leave it alone. */
13110 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13111 over COND_EXPR in cases such as floating point comparisons. */
13118 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13123 {
13124 /* sign_bit_p only checks ARG1 bits within A's precision.
13125 If <sign bit of A> has wider type than A, bits outside
13126 of A's precision in <sign bit of A> need to be checked.
13127 If they are all 0, this optimization needs to be done
13128 in unsigned A's type, if they are all 1 in signed A's type,
13129 otherwise this can't be done. */
13134 {
13136 HOST_WIDE_INT mask_hi;
13138 tree tem_type;
13146 {
13150 }
13151 else
13152 {
13156 }
13158 {
13162 }
13163 else
13169 {
13172 }
13175 {
13178 }
13179 else
13181 }
13188 arg1)));
13189 }
13191 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13192 already handled above. */
13197 {
13206 }
13208 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13209 is probably obsolete because the first operand should be a
13210 truth value (that's why we have the two cases above), but let's
13211 leave it in until we can confirm this for all front-ends. */
13222 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13228 arg1);
13230 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13234 {
13235 /* Only perform transformation if ARG0 is easily inverted. */
13240 arg1);
13241 }
13243 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13247 {
13248 /* Only perform transformation if ARG0 is easily inverted. */
13253 op2);
13254 }
13256 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13262 op2);
13267 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13268 of fold_ternary on them. */
13277 {
13286 {
13291 else
13292 {
13294 tree value;
13298 }
13303 else
13305 }
13306 }
13312 }
13314 /* Perform constant folding and related simplification of EXPR.
13315 The related simplifications include x*1 => x, x*0 => 0, etc.,
13316 and application of the associative law.
13317 NOP_EXPR conversions may be removed freely (as long as we
13318 are careful not to change the type of the overall expression).
13319 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13320 but we can constant-fold them if they have constant operands. */
13322 #ifdef ENABLE_FOLD_CHECKING
13323 # define fold(x) fold_1 (x)
13325 static
13326 #endif
13327 tree
13329 {
13333 tree tem;
13335 /* Return right away if a constant. */
13339 /* CALL_EXPR-like objects with variable numbers of operands are
13340 treated specially. */
13342 {
13344 {
13347 }
13349 }
13353 {
13358 {
13376 }
13377 }
13380 {
13387 }
13389 #ifdef ENABLE_FOLD_CHECKING
13390 #undef fold
13396 /* When --enable-checking=fold, compute a digest of expr before
13397 and after actual fold call to see if fold did not accidentally
13398 change original expr. */
13400 tree
13402 {
13403 tree ret;
13406 htab_t ht;
13425 }
13427 void
13429 {
13432 htab_t ht;
13442 }
13444 static void
13446 {
13448 }
13450 static void
13452 {
13458 recursive_label:
13472 {
13473 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13477 }
13482 {
13483 /* Allow these fields to be modified. */
13484 tree tmp;
13491 {
13494 }
13495 }
13504 {
13507 {
13521 }
13525 {
13538 }
13555 {
13561 }
13566 {
13570 }
13581 {
13584 }
13594 }
13595 }
13597 /* Helper function for outputting the checksum of a tree T. When
13598 debugging with gdb, you can "define mynext" to be "next" followed
13599 by "call debug_fold_checksum (op0)", then just trace down till the
13600 outputs differ. */
13602 void
13604 {
13619 }
13621 #endif
13623 /* Fold a unary tree expression with code CODE of type TYPE with an
13624 operand OP0. Return a folded expression if successful. Otherwise,
13625 return a tree expression with code CODE of type TYPE with an
13626 operand OP0. */
13628 tree
13630 {
13631 tree tem;
13632 #ifdef ENABLE_FOLD_CHECKING
13635 htab_t ht;
13642 #endif
13648 #ifdef ENABLE_FOLD_CHECKING
13656 #endif
13658 }
13660 /* Fold a binary tree expression with code CODE of type TYPE with
13661 operands OP0 and OP1. Return a folded expression if successful.
13662 Otherwise, return a tree expression with code CODE of type TYPE
13663 with operands OP0 and OP1. */
13665 tree
13667 MEM_STAT_DECL)
13668 {
13669 tree tem;
13670 #ifdef ENABLE_FOLD_CHECKING
13676 htab_t ht;
13688 #endif
13694 #ifdef ENABLE_FOLD_CHECKING
13710 #endif
13712 }
13714 /* Fold a ternary tree expression with code CODE of type TYPE with
13715 operands OP0, OP1, and OP2. Return a folded expression if
13716 successful. Otherwise, return a tree expression with code CODE of
13717 type TYPE with operands OP0, OP1, and OP2. */
13719 tree
13721 MEM_STAT_DECL)
13722 {
13723 tree tem;
13724 #ifdef ENABLE_FOLD_CHECKING
13732 htab_t ht;
13749 #endif
13756 #ifdef ENABLE_FOLD_CHECKING
13780 #endif
13782 }
13784 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13785 arguments in ARGARRAY, and a null static chain.
13786 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13787 of type TYPE from the given operands as constructed by build_call_array. */
13789 tree
13791 {
13792 tree tem;
13793 #ifdef ENABLE_FOLD_CHECKING
13799 htab_t ht;
13813 #endif
13817 #ifdef ENABLE_FOLD_CHECKING
13834 #endif
13836 }
13838 /* Perform constant folding and related simplification of initializer
13839 expression EXPR. These behave identically to "fold_buildN" but ignore
13840 potential run-time traps and exceptions that fold must preserve. */
13842 #define START_FOLD_INIT \
13843 int saved_signaling_nans = flag_signaling_nans;\
13844 int saved_trapping_math = flag_trapping_math;\
13845 int saved_rounding_math = flag_rounding_math;\
13846 int saved_trapv = flag_trapv;\
13847 int saved_folding_initializer = folding_initializer;\
13848 flag_signaling_nans = 0;\
13849 flag_trapping_math = 0;\
13850 flag_rounding_math = 0;\
13851 flag_trapv = 0;\
13852 folding_initializer = 1;
13854 #define END_FOLD_INIT \
13855 flag_signaling_nans = saved_signaling_nans;\
13856 flag_trapping_math = saved_trapping_math;\
13857 flag_rounding_math = saved_rounding_math;\
13858 flag_trapv = saved_trapv;\
13859 folding_initializer = saved_folding_initializer;
13861 tree
13863 {
13864 tree result;
13865 START_FOLD_INIT;
13869 END_FOLD_INIT;
13871 }
13873 tree
13875 {
13876 tree result;
13877 START_FOLD_INIT;
13881 END_FOLD_INIT;
13883 }
13885 tree
13887 tree op2)
13888 {
13889 tree result;
13890 START_FOLD_INIT;
13894 END_FOLD_INIT;
13896 }
13898 tree
13901 {
13902 tree result;
13903 START_FOLD_INIT;
13907 END_FOLD_INIT;
13909 }
13911 #undef START_FOLD_INIT
13912 #undef END_FOLD_INIT
13914 /* Determine if first argument is a multiple of second argument. Return 0 if
13915 it is not, or we cannot easily determined it to be.
13917 An example of the sort of thing we care about (at this point; this routine
13918 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13919 fold cases do now) is discovering that
13921 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13923 is a multiple of
13925 SAVE_EXPR (J * 8)
13927 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13929 This code also handles discovering that
13931 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13933 is a multiple of 8 so we don't have to worry about dealing with a
13934 possible remainder.
13936 Note that we *look* inside a SAVE_EXPR only to determine how it was
13937 calculated; it is not safe for fold to do much of anything else with the
13938 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13939 at run time. For example, the latter example above *cannot* be implemented
13940 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13941 evaluation time of the original SAVE_EXPR is not necessarily the same at
13942 the time the new expression is evaluated. The only optimization of this
13943 sort that would be valid is changing
13945 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13947 divided by 8 to
13949 SAVE_EXPR (I) * SAVE_EXPR (J)
13951 (where the same SAVE_EXPR (J) is used in the original and the
13952 transformed version). */
13954 int
13956 {
13964 {
13966 /* Bitwise and provides a power of two multiple. If the mask is
13967 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13970 /* FALLTHRU */
13983 {
13987 /* const_binop may not detect overflow correctly,
13988 so check for it explicitly here. */
13994 size_one_node,
13998 }
14002 /* Can't handle conversions from non-integral or wider integral type. */
14008 /* .. fall through ... */
14025 }
14026 }
14028 /* Return true if `t' is known to be non-negative. If the return
14029 value is based on the assumption that signed overflow is undefined,
14030 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14031 *STRICT_OVERFLOW_P. */
14033 bool
14035 {
14043 {
14045 /* Query VRP to see if it has recorded any information about
14046 the range of this object. */
14050 /* We can't return 1 if flag_wrapv is set because
14051 ABS_EXPR<INT_MIN> = INT_MIN. */
14055 {
14058 }
14074 strict_overflow_p)
14076 strict_overflow_p));
14078 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14079 both unsigned and at least 2 bits shorter than the result. */
14083 {
14088 {
14092 }
14093 }
14098 {
14099 /* x * x for floating point x is always non-negative. */
14103 strict_overflow_p)
14105 strict_overflow_p));
14106 }
14108 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14109 both unsigned and their total bits is shorter than the result. */
14113 {
14120 }
14126 strict_overflow_p)
14128 strict_overflow_p));
14139 strict_overflow_p)
14141 strict_overflow_p));
14152 strict_overflow_p);
14158 strict_overflow_p);
14162 strict_overflow_p);
14166 strict_overflow_p)
14168 strict_overflow_p));
14171 {
14176 {
14179 strict_overflow_p);
14181 {
14185 strict_overflow_p);
14186 }
14187 }
14189 {
14192 strict_overflow_p);
14196 }
14197 }
14201 {
14205 /* If the initializer is non-void, then it's a normal expression
14206 that will be assigned to the slot. */
14210 /* Otherwise, the initializer sets the slot in some way. One common
14211 way is an assignment statement at the end of the initializer. */
14213 {
14221 else
14223 }
14228 strict_overflow_p);
14231 }
14234 {
14238 {
14256 /* Always true. */
14260 /* sqrt(-0.0) is -0.0. */
14264 strict_overflow_p);
14297 /* True if the 1st argument is nonnegative. */
14299 strict_overflow_p);
14302 /* True if the 1st OR 2nd arguments are nonnegative. */
14304 strict_overflow_p)
14306 strict_overflow_p)));
14309 /* True if the 1st AND 2nd arguments are nonnegative. */
14311 strict_overflow_p)
14313 strict_overflow_p)));
14316 /* True if the 2nd argument is nonnegative. */
14318 strict_overflow_p);
14321 /* True if the 1st argument is nonnegative or the second
14322 argument is an even integer. */
14324 {
14328 }
14330 strict_overflow_p);
14333 /* True if the 1st argument is nonnegative or the second
14334 argument is an even integer valued real. */
14336 {
14337 REAL_VALUE_TYPE c;
14338 HOST_WIDE_INT n;
14343 {
14344 REAL_VALUE_TYPE cint;
14349 }
14350 }
14352 strict_overflow_p);
14356 }
14357 }
14359 /* ... fall through ... */
14362 {
14366 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14367 have a signed:1 type (where the value is -1 and 0). */
14369 }
14370 }
14372 /* We don't know sign of `t', so be conservative and return false. */
14374 }
14376 /* Return true if `t' is known to be non-negative. Handle warnings
14377 about undefined signed overflow. */
14379 bool
14381 {
14388 "determining that expression is always "
14390 WARN_STRICT_OVERFLOW_MISC);
14392 }
14394 /* Return true when T is an address and is known to be nonzero.
14395 For floating point we further ensure that T is not denormal.
14396 Similar logic is present in nonzero_address in rtlanal.h.
14398 If the return value is based on the assumption that signed overflow
14399 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14400 change *STRICT_OVERFLOW_P. */
14402 bool
14404 {
14408 /* Doing something useful for floating point would need more work. */
14413 {
14415 /* Query VRP to see if it has recorded any information about
14416 the range of this object. */
14421 strict_overflow_p);
14429 {
14430 /* With the presence of negative values it is hard
14431 to say something. */
14438 /* One of operands must be positive and the other non-negative. */
14439 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14440 overflows, on a twos-complement machine the sum of two
14441 nonnegative numbers can never be zero. */
14443 strict_overflow_p)
14445 strict_overflow_p));
14446 }
14451 {
14453 strict_overflow_p)
14455 strict_overflow_p))
14456 {
14459 }
14460 }
14464 {
14470 strict_overflow_p));
14471 }
14475 {
14481 /* Weak declarations may link to NULL. */
14485 /* Constants are never weak. */
14490 }
14498 {
14502 }
14511 {
14514 }
14521 {
14525 /* When both operands are nonzero, then MAX must be too. */
14527 strict_overflow_p))
14530 /* MAX where operand 0 is positive is positive. */
14532 strict_overflow_p);
14533 }
14534 /* MAX where operand 1 is positive is positive. */
14539 {
14543 }
14551 strict_overflow_p);
14556 strict_overflow_p);
14560 strict_overflow_p)
14562 strict_overflow_p));
14569 }
14571 }
14573 /* Return true when T is an address and is known to be nonzero.
14574 Handle warnings about undefined signed overflow. */
14576 bool
14578 {
14585 "determining that expression is always "
14587 WARN_STRICT_OVERFLOW_MISC);
14589 }
14591 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14592 attempt to fold the expression to a constant without modifying TYPE,
14593 OP0 or OP1.
14595 If the expression could be simplified to a constant, then return
14596 the constant. If the expression would not be simplified to a
14597 constant, then return NULL_TREE. */
14599 tree
14601 {
14604 }
14606 /* Given the components of a unary expression CODE, TYPE and OP0,
14607 attempt to fold the expression to a constant without modifying
14608 TYPE or OP0.
14610 If the expression could be simplified to a constant, then return
14611 the constant. If the expression would not be simplified to a
14612 constant, then return NULL_TREE. */
14614 tree
14616 {
14619 }
14621 /* If EXP represents referencing an element in a constant string
14622 (either via pointer arithmetic or array indexing), return the
14623 tree representing the value accessed, otherwise return NULL. */
14625 tree
14627 {
14631 {
14633 tree index;
14634 tree string;
14638 else
14639 {
14643 /* Optimize the special-case of a zero lower bound.
14645 We convert the low_bound to sizetype to avoid some problems
14646 with constant folding. (E.g. suppose the lower bound is 1,
14647 and its mode is QI. Without the conversion,l (ARRAY
14648 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14649 +INDEX), which becomes (ARRAY+255+INDEX). Opps!) */
14654 }
14667 }
14669 }
14671 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14672 an integer constant, real, or fixed-point constant.
14674 TYPE is the type of the result. */
14676 static tree
14678 {
14682 {
14684 {
14686 HOST_WIDE_INT high;
14694 }
14701 {
14702 FIXED_VALUE_TYPE f;
14707 /* Propagate overflow flags. */
14709 {
14712 }
14716 }
14720 }
14723 }
14725 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14726 an integer constant or real constant.
14728 TYPE is the type of the result. */
14730 tree
14732 {
14736 {
14738 /* If the value is unsigned, then the absolute value is
14739 the same as the ordinary value. */
14742 /* Similarly, if the value is non-negative. */
14745 /* If the value is negative, then the absolute value is
14746 its negation. */
14747 else
14748 {
14750 HOST_WIDE_INT high;
14756 }
14762 else
14768 }
14771 }
14773 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14774 constant. TYPE is the type of the result. */
14776 static tree
14778 {
14788 }
14790 /* Given CODE, a relational operator, the target type, TYPE and two
14791 constant operands OP0 and OP1, return the result of the
14792 relational operation. If the result is not a compile time
14793 constant, then return NULL_TREE. */
14795 static tree
14797 {
14800 /* From here on, the only cases we handle are when the result is
14801 known to be a constant. */
14804 {
14808 /* Handle the cases where either operand is a NaN. */
14810 {
14812 {
14840 }
14843 }
14846 }
14849 {
14853 }
14855 /* Handle equality/inequality of complex constants. */
14857 {
14868 else
14870 }
14872 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14874 To compute GT, swap the arguments and do LT.
14875 To compute GE, do LT and invert the result.
14876 To compute LE, swap the arguments, do LT and invert the result.
14877 To compute NE, do EQ and invert the result.
14879 Therefore, the code below must handle only EQ and LT. */
14882 {
14887 }
14889 /* Note that it is safe to invert for real values here because we
14890 have already handled the one case that it matters. */
14894 {
14897 }
14899 /* Compute a result for LT or EQ if args permit;
14900 Otherwise return T. */
14902 {
14907 else
14909 }
14910 else
14916 }
14918 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14919 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14920 itself. */
14922 tree
14924 {
14925 /* If the expression does not have side effects then we don't have to wrap
14926 it with a cleanup point expression. */
14930 /* If the expression is a return, check to see if the expression inside the
14931 return has no side effects or the right hand side of the modify expression
14932 inside the return. If either don't have side effects set we don't need to
14933 wrap the expression in a cleanup point expression. Note we don't check the
14934 left hand side of the modify because it should always be a return decl. */
14936 {
14943 }
14946 }
14948 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14949 of an indirection through OP0, or NULL_TREE if no simplification is
14950 possible. */
14952 tree
14954 {
14956 tree subtype;
14964 {
14967 /* *&CONST_DECL -> to the value of the const decl. */
14970 /* *&p => p; make sure to handle *&"str"[cst] here. */
14972 {
14976 else
14978 }
14979 /* *(foo *)&fooarray => fooarray[0] */
14982 {
14988 }
14989 /* *(foo *)&complexfoo => __real__ complexfoo */
14993 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14996 {
15000 }
15001 }
15003 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15006 {
15009 tree op00type;
15016 {
15020 }
15021 }
15023 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15026 {
15027 tree type_domain;
15034 }
15037 }
15039 /* Builds an expression for an indirection through T, simplifying some
15040 cases. */
15042 tree
15044 {
15050 else
15052 }
15054 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15056 tree
15058 {
15063 else
15065 }
15067 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15068 whose result is ignored. The type of the returned tree need not be
15069 the same as the original expression. */
15071 tree
15073 {
15079 {
15090 else
15096 {
15112 }
15117 }
15118 }
15120 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15121 This can only be applied to objects of a sizetype. */
15123 tree
15125 {
15132 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15133 have to do anything. Only do this when we are not given a const,
15134 because in that case, this check is more expensive than just
15135 doing it. */
15137 {
15142 }
15144 /* If divisor is a power of two, simplify this to bit manipulation. */
15146 {
15148 {
15161 {
15162 high++;
15165 }
15169 }
15170 else
15171 {
15172 tree t;
15178 }
15179 }
15180 else
15181 {
15186 }
15189 }
15191 /* Likewise, but round down. */
15193 tree
15195 {
15202 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15203 have to do anything. Only do this when we are not given a const,
15204 because in that case, this check is more expensive than just
15205 doing it. */
15207 {
15212 }
15214 /* If divisor is a power of two, simplify this to bit manipulation. */
15216 {
15217 tree t;
15221 }
15222 else
15223 {
15228 }
15231 }
15233 /* Returns the pointer to the base of the object addressed by EXP and
15234 extracts the information about the offset of the access, storing it
15235 to PBITPOS and POFFSET. */
15237 static tree
15240 {
15241 tree core;
15244 HOST_WIDE_INT bitsize;
15247 {
15252 }
15253 else
15254 {
15258 }
15261 }
15263 /* Returns true if addresses of E1 and E2 differ by a constant, false
15264 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15266 bool
15268 {
15282 {
15292 }
15294 {
15295 /* If only one of the offsets is non-constant, the difference cannot
15296 be a constant. */
15298 }
15299 else
15304 }
15306 /* Simplify the floating point expression EXP when the sign of the
15307 result is not significant. Return NULL_TREE if no simplification
15308 is possible. */
15310 tree
15312 {
15316 {
15351 {
15354 {
15356 /* Strip copysign function call, return the 1st argument. */
15362 /* Strip sign ops from the argument of "odd" math functions. */
15364 {
15368 }
15370 }
15371 }
15376 }
15378 }