| blob | a02cfb7b1f012b444cfb5cb62f0f79dee3c7b64d |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
87 /* Nonzero if we are folding constants inside an initializer; zero
88 otherwise. */
91 /* The following constants represent a bit based encoding of GCC's
92 comparison operators. This encoding simplifies transformations
93 on relational comparison operators, such as AND and OR. */
111 };
129 HOST_WIDE_INT *,
162 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
163 Otherwise, return LOC. */
165 static location_t
167 {
170 }
172 /* Similar to protected_set_expr_location, but never modify x in place,
173 if location can and needs to be set, unshare it. */
177 {
183 {
186 }
188 }
189 \f
190 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
191 division and returns the quotient. Otherwise returns
192 NULL_TREE. */
194 tree
196 {
197 widest_int quo;
204 }
205 \f
206 /* This is nonzero if we should defer warnings about undefined
207 overflow. This facility exists because these warnings are a
208 special case. The code to estimate loop iterations does not want
209 to issue any warnings, since it works with expressions which do not
210 occur in user code. Various bits of cleanup code call fold(), but
211 only use the result if it has certain characteristics (e.g., is a
212 constant); that code only wants to issue a warning if the result is
213 used. */
217 /* If a warning about undefined overflow is deferred, this is the
218 warning. Note that this may cause us to turn two warnings into
219 one, but that is fine since it is sufficient to only give one
220 warning per expression. */
224 /* If a warning about undefined overflow is deferred, this is the
225 level at which the warning should be emitted. */
229 /* Start deferring overflow warnings. We could use a stack here to
230 permit nested calls, but at present it is not necessary. */
232 void
234 {
236 }
238 /* Stop deferring overflow warnings. If there is a pending warning,
239 and ISSUE is true, then issue the warning if appropriate. STMT is
240 the statement with which the warning should be associated (used for
241 location information); STMT may be NULL. CODE is the level of the
242 warning--a warn_strict_overflow_code value. This function will use
243 the smaller of CODE and the deferred code when deciding whether to
244 issue the warning. CODE may be zero to mean to always use the
245 deferred code. */
247 void
249 {
251 location_t locus;
256 {
262 }
273 /* Use the smallest code level when deciding to issue the
274 warning. */
283 else
286 }
288 /* Stop deferring overflow warnings, ignoring any deferred
289 warnings. */
291 void
293 {
295 }
297 /* Whether we are deferring overflow warnings. */
299 bool
301 {
303 }
305 /* This is called when we fold something based on the fact that signed
306 overflow is undefined. */
308 static void
310 {
312 {
315 {
318 }
319 }
322 }
323 \f
324 /* Return true if the built-in mathematical function specified by CODE
325 is odd, i.e. -f(x) == f(-x). */
327 static bool
329 {
331 {
365 }
367 }
369 /* Check whether we may negate an integer constant T without causing
370 overflow. */
372 bool
374 {
375 tree type;
384 }
386 /* Determine whether an expression T can be cheaply negated using
387 the function negate_expr without introducing undefined overflow. */
389 static bool
391 {
392 tree type;
401 {
406 /* Check that -CST will not overflow type. */
419 /* We want to canonicalize to positive real constants. Pretend
420 that only negative ones can be easily negated. */
428 {
439 }
452 /* -(A + B) -> (-B) - A. */
457 /* -(A + B) -> (-A) - B. */
461 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
471 /* Fall through. */
482 /* In general we can't negate A / B, because if A is INT_MIN and
483 B is 1, we may turn this into INT_MIN / -1 which is undefined
484 and actually traps on some architectures. But if overflow is
485 undefined, we can negate, because - (INT_MIN / 1) is an
486 overflow. */
488 {
491 /* If overflow is undefined then we have to be careful because
492 we ask whether it's ok to associate the negate with the
493 division which is not ok for example for
494 -((a - b) / c) where (-(a - b)) / c may invoke undefined
495 overflow because of negating INT_MIN. So do not use
496 negate_expr_p here but open-code the two important cases. */
501 }
507 /* Negate -((double)float) as (double)(-float). */
509 {
513 }
517 /* Negate -f(x) as f(-x). */
523 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
525 {
529 }
534 }
536 }
538 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
539 simplification is possible.
540 If negate_expr_p would return true for T, NULL_TREE will never be
541 returned. */
543 static tree
545 {
547 tree tem;
550 {
551 /* Convert - (~A) to A + 1. */
577 {
582 }
586 {
591 {
595 }
598 }
621 {
622 /* -(A + B) -> (-B) - A. */
626 {
630 }
632 /* -(A + B) -> (-A) - B. */
634 {
638 }
639 }
643 /* - (A - B) -> B - A */
655 /* Fall through. */
659 {
668 }
674 /* In general we can't negate A / B, because if A is INT_MIN and
675 B is 1, we may turn this into INT_MIN / -1 which is undefined
676 and actually traps on some architectures. But if overflow is
677 undefined, we can negate, because - (INT_MIN / 1) is an
678 overflow. */
680 {
685 {
692 }
693 /* If overflow is undefined then we have to be careful because
694 we ask whether it's ok to associate the negate with the
695 division which is not ok for example for
696 -((a - b) / c) where (-(a - b)) / c may invoke undefined
697 overflow because of negating INT_MIN. So do not use
698 negate_expr_p here but open-code the two important cases. */
707 }
711 /* Convert -((double)float) into (double)(-float). */
713 {
717 }
721 /* Negate -f(x) as f(-x). */
724 {
730 }
734 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
736 {
739 {
746 }
747 }
752 }
755 }
757 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
758 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
759 return NULL_TREE. */
761 static tree
763 {
765 location_t loc;
778 }
779 \f
780 /* Split a tree IN into a constant, literal and variable parts that could be
781 combined with CODE to make IN. "constant" means an expression with
782 TREE_CONSTANT but that isn't an actual constant. CODE must be a
783 commutative arithmetic operation. Store the constant part into *CONP,
784 the literal in *LITP and return the variable part. If a part isn't
785 present, set it to null. If the tree does not decompose in this way,
786 return the entire tree as the variable part and the other parts as null.
788 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
789 case, we negate an operand that was subtracted. Except if it is a
790 literal for which we use *MINUS_LITP instead.
792 If NEGATE_P is true, we are negating all of IN, again except a literal
793 for which we use *MINUS_LITP instead.
795 If IN is itself a literal or constant, return it as appropriate.
797 Note that we do not guarantee that any of the three values will be the
798 same type as IN, but they will have the same signedness and mode. */
800 static tree
803 {
810 /* Strip any conversions that don't change the machine mode or signedness. */
819 /* We can associate addition and subtraction together (even
820 though the C standard doesn't say so) for integers because
821 the value is not affected. For reals, the value might be
822 affected, so we can't. */
825 {
831 /* First see if either of the operands is a literal, then a constant. */
844 /* If we haven't dealt with either operand, this is not a case we can
845 decompose. Otherwise, VAR is either of the ones remaining, if any. */
850 else
853 /* Now do any needed negations. */
860 }
863 {
864 /* -X - 1 is folded to ~X, undo that here. */
867 }
870 else
874 {
881 }
884 }
886 /* Re-associate trees split by the above function. T1 and T2 are
887 either expressions to associate or null. Return the new
888 expression, if any. LOC is the location of the new expression. If
889 we build an operation, do it in TYPE and with CODE. */
891 static tree
893 {
899 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
900 try to fold this since we will have infinite recursion. But do
901 deal with any NEGATE_EXPRs. */
904 {
906 {
919 }
921 {
924 }
928 }
932 }
933 \f
934 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
935 for use in int_const_binop, size_binop and size_diffop. */
937 static bool
939 {
946 {
955 }
960 }
963 /* Combine two integer constants ARG1 and ARG2 under operation CODE
964 to produce a new constant. Return NULL_TREE if we don't know how
965 to evaluate CODE at compile-time. */
967 static tree
970 {
971 wide_int res;
972 tree t;
981 {
997 {
1001 else
1003 }
1006 /* It's unclear from the C standard whether shifts can overflow.
1007 The following code ignores overflow; perhaps a C standard
1008 interpretation ruling is needed. */
1010 else
1017 {
1021 else
1023 }
1027 else
1106 }
1114 }
1116 tree
1118 {
1120 }
1122 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1123 constant. We assume ARG1 and ARG2 have the same data type, or at least
1124 are the same kind of constant and the same machine mode. Return zero if
1125 combining the constants is not allowed in the current operating mode. */
1127 static tree
1129 {
1130 /* Sanity check for the recursive cases. */
1138 {
1144 }
1147 {
1148 machine_mode mode;
1149 REAL_VALUE_TYPE d1;
1150 REAL_VALUE_TYPE d2;
1151 REAL_VALUE_TYPE value;
1152 REAL_VALUE_TYPE result;
1156 /* The following codes are handled by real_arithmetic. */
1158 {
1169 }
1177 /* Don't perform operation if we honor signaling NaNs and
1178 either operand is a NaN. */
1183 /* Don't perform operation if it would raise a division
1184 by zero exception. */
1190 /* If either operand is a NaN, just return it. Otherwise, set up
1191 for floating-point trap; we return an overflow. */
1200 /* Don't constant fold this floating point operation if
1201 the result has overflowed and flag_trapping_math. */
1209 /* Don't constant fold this floating point operation if the
1210 result may dependent upon the run-time rounding mode and
1211 flag_rounding_math is set, or if GCC's software emulation
1212 is unable to accurately represent the result. */
1222 }
1225 {
1226 FIXED_VALUE_TYPE f1;
1227 FIXED_VALUE_TYPE f2;
1228 FIXED_VALUE_TYPE result;
1233 /* The following codes are handled by fixed_arithmetic. */
1235 {
1247 {
1254 }
1259 }
1266 /* Propagate overflow flags. */
1270 }
1273 {
1282 {
1293 mpc_mul);
1307 mpc_div);
1308 /* Fallthru ... */
1314 {
1315 /* Keep this algorithm in sync with
1316 tree-complex.c:expand_complex_div_straight().
1318 Expand complex division to scalars, straightforward algorithm.
1319 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1320 t = br*br + bi*bi
1321 */
1322 tree magsquared
1326 tree t1
1330 tree t2
1337 }
1338 else
1339 {
1340 /* Keep this algorithm in sync with
1341 tree-complex.c:expand_complex_div_wide().
1343 Expand complex division to scalars, modified algorithm to minimize
1344 overflow with wide input ranges. */
1350 {
1351 /* In the TRUE branch, we compute
1352 ratio = br/bi;
1353 div = (br * ratio) + bi;
1354 tr = (ar * ratio) + ai;
1355 ti = (ai * ratio) - ar;
1356 tr = tr / div;
1357 ti = ti / div; */
1368 }
1369 else
1370 {
1371 /* In the FALSE branch, we compute
1372 ratio = d/c;
1373 divisor = (d * ratio) + c;
1374 tr = (b * ratio) + a;
1375 ti = b - (a * ratio);
1376 tr = tr / div;
1377 ti = ti / div; */
1389 }
1390 }
1395 }
1399 }
1403 {
1409 {
1415 /* It is possible that const_binop cannot handle the given
1416 code and return NULL_TREE */
1419 }
1422 }
1424 /* Shifts allow a scalar offset for a vector. */
1427 {
1433 {
1438 /* It is possible that const_binop cannot handle the given
1439 code and return NULL_TREE. */
1442 }
1445 }
1447 }
1449 /* Overload that adds a TYPE parameter to be able to dispatch
1450 to fold_relational_const. */
1452 tree
1454 {
1458 /* ??? Until we make the const_binop worker take the type of the
1459 result as argument put those cases that need it here. */
1461 {
1472 {
1488 {
1494 }
1497 }
1503 {
1528 {
1541 }
1544 }
1547 }
1552 /* Make sure type and arg0 have the same saturating flag. */
1557 }
1559 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1560 Return zero if computing the constants is not possible. */
1562 tree
1564 {
1566 {
1567 CASE_CONVERT:
1582 {
1583 /* Can't call fold_negate_const directly here as that doesn't
1584 handle all cases and we might not be able to negate some
1585 constants. */
1590 }
1599 {
1603 }
1609 /* Perform BIT_NOT_EXPR on each element individually. */
1611 {
1613 tree elem;
1618 {
1624 }
1627 }
1649 {
1668 else
1672 {
1676 }
1679 }
1684 {
1698 {
1703 }
1706 {
1710 }
1713 }
1717 }
1720 }
1722 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1723 indicates which particular sizetype to create. */
1725 tree
1727 {
1729 }
1730 \f
1731 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1732 is a tree code. The type of the result is taken from the operands.
1733 Both must be equivalent integer types, ala int_binop_types_match_p.
1734 If the operands are constant, so is the result. */
1736 tree
1738 {
1747 /* Handle the special case of two integer constants faster. */
1749 {
1750 /* And some specific cases even faster than that. */
1752 {
1757 }
1759 {
1762 }
1764 {
1767 }
1769 /* Handle general case of two integer constants. For sizetype
1770 constant calculations we always want to know about overflow,
1771 even in the unsigned case. */
1773 }
1776 }
1778 /* Given two values, either both of sizetype or both of bitsizetype,
1779 compute the difference between the two values. Return the value
1780 in signed type corresponding to the type of the operands. */
1782 tree
1784 {
1786 tree ctype;
1791 /* If the type is already signed, just do the simple thing. */
1799 else
1802 /* If either operand is not a constant, do the conversions to the signed
1803 type and subtract. The hardware will do the right thing with any
1804 overflow in the subtraction. */
1810 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1811 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1812 overflow) and negate (which can't either). Special-case a result
1813 of zero while we're here. */
1819 else
1823 MINUS_EXPR,
1825 }
1826 \f
1827 /* A subroutine of fold_convert_const handling conversions of an
1828 INTEGER_CST to another integer type. */
1830 static tree
1832 {
1833 /* Given an integer constant, make new constant with new type,
1834 appropriately sign-extended or truncated. Use widest_int
1835 so that any extension is done according ARG1's type. */
1839 }
1841 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1842 to an integer type. */
1844 static tree
1846 {
1848 tree t;
1850 /* The following code implements the floating point to integer
1851 conversion rules required by the Java Language Specification,
1852 that IEEE NaNs are mapped to zero and values that overflow
1853 the target precision saturate, i.e. values greater than
1854 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1855 are mapped to INT_MIN. These semantics are allowed by the
1856 C and C++ standards that simply state that the behavior of
1857 FP-to-integer conversion is unspecified upon overflow. */
1859 wide_int val;
1860 REAL_VALUE_TYPE r;
1864 {
1871 }
1873 /* If R is NaN, return zero and show we have an overflow. */
1875 {
1878 }
1880 /* See if R is less than the lower bound or greater than the
1881 upper bound. */
1884 {
1888 {
1891 }
1892 }
1895 {
1898 {
1901 {
1904 }
1905 }
1906 }
1913 }
1915 /* A subroutine of fold_convert_const handling conversions of a
1916 FIXED_CST to an integer type. */
1918 static tree
1920 {
1921 tree t;
1925 /* Right shift FIXED_CST to temp by fbit. */
1929 {
1931 HOST_BITS_PER_DOUBLE_INT,
1934 /* Left shift temp to temp_trunc by fbit. */
1936 HOST_BITS_PER_DOUBLE_INT,
1938 }
1939 else
1940 {
1943 }
1945 /* If FIXED_CST is negative, we need to round the value toward 0.
1946 By checking if the fractional bits are not zero to add 1 to temp. */
1952 /* Given a fixed-point constant, make new constant with new type,
1953 appropriately sign-extended or truncated. */
1961 }
1963 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1964 to another floating point type. */
1966 static tree
1968 {
1969 REAL_VALUE_TYPE value;
1970 tree t;
1975 /* If converting an infinity or NAN to a representation that doesn't
1976 have one, set the overflow bit so that we can produce some kind of
1977 error message at the appropriate point if necessary. It's not the
1978 most user-friendly message, but it's better than nothing. */
1985 /* Regular overflow, conversion produced an infinity in a mode that
1986 can't represent them. */
1991 else
1994 }
1996 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1997 to a floating point type. */
1999 static tree
2001 {
2002 REAL_VALUE_TYPE value;
2003 tree t;
2010 }
2012 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2013 to another fixed-point type. */
2015 static tree
2017 {
2018 FIXED_VALUE_TYPE value;
2019 tree t;
2026 /* Propagate overflow flags. */
2030 }
2032 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2033 to a fixed-point type. */
2035 static tree
2037 {
2038 FIXED_VALUE_TYPE value;
2039 tree t;
2041 double_int di;
2048 else
2056 /* Propagate overflow flags. */
2060 }
2062 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2063 to a fixed-point type. */
2065 static tree
2067 {
2068 FIXED_VALUE_TYPE value;
2069 tree t;
2077 /* Propagate overflow flags. */
2081 }
2083 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2084 type TYPE. If no simplification can be done return NULL_TREE. */
2086 static tree
2088 {
2094 {
2101 }
2103 {
2110 }
2112 {
2119 }
2121 }
2123 /* Construct a vector of zero elements of vector type TYPE. */
2125 static tree
2127 {
2128 tree t;
2132 }
2134 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2136 bool
2138 {
2153 {
2172 }
2173 }
2175 /* Convert expression ARG to type TYPE. Used by the middle-end for
2176 simple conversions in preference to calling the front-end's convert. */
2178 tree
2180 {
2182 tree tem;
2193 {
2196 /* Handle conversions between pointers to different address spaces. */
2201 /* fall through */
2206 {
2210 }
2224 {
2228 }
2230 {
2234 }
2236 {
2240 }
2243 {
2261 }
2266 {
2270 }
2273 {
2287 }
2291 {
2300 integer_zero_node));
2302 {
2306 {
2312 }
2320 }
2324 }
2342 }
2343 fold_convert_exit:
2346 }
2347 \f
2348 /* Return false if expr can be assumed not to be an lvalue, true
2349 otherwise. */
2351 static bool
2353 {
2354 /* We only need to wrap lvalue tree codes. */
2356 {
2387 /* Assume the worst for front-end tree codes. */
2391 }
2394 }
2396 /* Return an expr equal to X but certainly not valid as an lvalue. */
2398 tree
2400 {
2401 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2402 us. */
2409 }
2411 /* When pedantic, return an expr equal to X but certainly not valid as a
2412 pedantic lvalue. Otherwise, return X. */
2414 static tree
2416 {
2418 }
2419 \f
2420 /* Given a tree comparison code, return the code that is the logical inverse.
2421 It is generally not safe to do this for floating-point comparisons, except
2422 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2423 ERROR_MARK in this case. */
2425 enum tree_code
2427 {
2433 {
2464 }
2465 }
2467 /* Similar, but return the comparison that results if the operands are
2468 swapped. This is safe for floating-point. */
2470 enum tree_code
2472 {
2474 {
2500 }
2501 }
2504 /* Convert a comparison tree code from an enum tree_code representation
2505 into a compcode bit-based encoding. This function is the inverse of
2506 compcode_to_comparison. */
2508 static enum comparison_code
2510 {
2512 {
2543 }
2544 }
2546 /* Convert a compcode bit-based encoding of a comparison operator back
2547 to GCC's enum tree_code representation. This function is the
2548 inverse of comparison_to_compcode. */
2550 static enum tree_code
2552 {
2554 {
2585 }
2586 }
2588 /* Return a tree for the comparison which is the combination of
2589 doing the AND or OR (depending on CODE) of the two operations LCODE
2590 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2591 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2592 if this makes the transformation invalid. */
2594 tree
2599 {
2606 {
2617 }
2620 {
2621 /* Eliminate unordered comparisons, as well as LTGT and ORD
2622 which are not used unless the mode has NaNs. */
2628 }
2630 {
2631 /* Check that the original operation and the optimized ones will trap
2632 under the same condition. */
2643 /* In a short-circuited boolean expression the LHS might be
2644 such that the RHS, if evaluated, will never trap. For
2645 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2646 if neither x nor y is NaN. (This is a mixed blessing: for
2647 example, the expression above will never trap, hence
2648 optimizing it to x < y would be invalid). */
2653 /* If the comparison was short-circuited, and only the RHS
2654 trapped, we may now generate a spurious trap. */
2659 /* If we changed the conditions that cause a trap, we lose. */
2662 }
2668 else
2669 {
2674 }
2675 }
2676 \f
2677 /* Return nonzero if two operands (typically of the same tree node)
2678 are necessarily equal. If either argument has side-effects this
2679 function returns zero. FLAGS modifies behavior as follows:
2681 If OEP_ONLY_CONST is set, only return nonzero for constants.
2682 This function tests whether the operands are indistinguishable;
2683 it does not test whether they are equal using C's == operation.
2684 The distinction is important for IEEE floating point, because
2685 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2686 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2688 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2689 even though it may hold multiple values during a function.
2690 This is because a GCC tree node guarantees that nothing else is
2691 executed between the evaluation of its "operands" (which may often
2692 be evaluated in arbitrary order). Hence if the operands themselves
2693 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2694 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2695 unset means assuming isochronic (or instantaneous) tree equivalence.
2696 Unless comparing arbitrary expression trees, such as from different
2697 statements, this flag can usually be left unset.
2699 If OEP_PURE_SAME is set, then pure functions with identical arguments
2700 are considered the same. It is used when the caller has other ways
2701 to ensure that global memory is unchanged in between. */
2703 int
2705 {
2706 /* If either is ERROR_MARK, they aren't equal. */
2712 /* Similar, if either does not have a type (like a released SSA name),
2713 they aren't equal. */
2717 /* Check equality of integer constants before bailing out due to
2718 precision differences. */
2722 /* If both types don't have the same signedness, then we can't consider
2723 them equal. We must check this before the STRIP_NOPS calls
2724 because they may change the signedness of the arguments. As pointers
2725 strictly don't have a signedness, require either two pointers or
2726 two non-pointers as well. */
2731 /* We cannot consider pointers to different address space equal. */
2737 /* If both types don't have the same precision, then it is not safe
2738 to strip NOPs. */
2746 /* In case both args are comparisons but with different comparison
2747 code, try to swap the comparison operands of one arg to produce
2748 a match and compare that variant. */
2752 {
2760 }
2763 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2767 /* This is needed for conversions and for COMPONENT_REF.
2768 Might as well play it safe and always test this. */
2774 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2775 We don't care about side effects in that case because the SAVE_EXPR
2776 takes care of that for us. In all other cases, two expressions are
2777 equal if they have no side effects. If we have two identical
2778 expressions with side effects that should be treated the same due
2779 to the only side effects being identical SAVE_EXPR's, that will
2780 be detected in the recursive calls below.
2781 If we are taking an invariant address of two identical objects
2782 they are necessarily equal as well. */
2789 /* Next handle constant cases, those for which we can return 1 even
2790 if ONLY_CONST is set. */
2793 {
2808 {
2809 /* If we do not distinguish between signed and unsigned zero,
2810 consider them equal. */
2813 }
2817 {
2824 {
2828 }
2830 }
2834 flags)
2836 flags));
2850 }
2855 /* Define macros to test an operand from arg0 and arg1 for equality and a
2856 variant that allows null and views null as being different from any
2857 non-null value. In the latter case, if either is null, the both
2858 must be; otherwise, do the normal comparison. */
2859 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2860 TREE_OPERAND (arg1, N), flags)
2862 #define OP_SAME_WITH_NULL(N) \
2863 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2864 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2867 {
2869 /* Two conversions are equal only if signedness and modes match. */
2871 {
2872 CASE_CONVERT:
2880 }
2890 /* For commutative ops, allow the other order. */
2898 /* If either of the pointer (or reference) expressions we are
2899 dereferencing contain a side effect, these cannot be equal,
2900 but their addresses can be. */
2907 {
2922 /* Require equal access sizes, and similar pointer types.
2923 We can have incomplete types for array references of
2924 variable-sized arrays from the Fortran frontend
2925 though. Also verify the types are compatible. */
2933 || (alias_ptr_types_compatible_p
2945 /* TARGET_MEM_REF require equal extra operands. */
2953 /* Operands 2 and 3 may be null.
2954 Compare the array index by value if it is constant first as we
2955 may have different types but same value here. */
2966 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
2967 may be NULL when we're called to compare MEM_EXPRs. */
2982 }
2986 {
3004 /* The multiplcation operands are commutative. */
3005 /* FALLTHRU */
3013 /* Otherwise take into account this is a commutative operation. */
3026 }
3030 {
3034 /* If not both CALL_EXPRs are either internal or normal function
3035 functions, then they are not equal. */
3038 {
3039 /* If the CALL_EXPRs call different internal functions, then they
3040 are not equal. */
3043 }
3044 else
3045 {
3046 /* If the CALL_EXPRs call different functions, then they are not
3047 equal. */
3049 flags))
3051 }
3053 {
3057 else
3061 }
3063 /* Now see if all the arguments are the same. */
3064 {
3075 /* If we get here and both argument lists are exhausted
3076 then the CALL_EXPRs are equal. */
3078 }
3081 }
3084 /* Consider __builtin_sqrt equal to sqrt. */
3092 }
3094 #undef OP_SAME
3095 #undef OP_SAME_WITH_NULL
3096 }
3097 \f
3098 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3099 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3101 When in doubt, return 0. */
3103 static int
3105 {
3117 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3118 and see if the inner values are the same. This removes any
3119 signedness comparison, which doesn't matter here. */
3126 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3127 actual comparison operand, ARG0.
3129 First throw away any conversions to wider types
3130 already present in the operands. */
3139 {
3142 /* Make sure shorter operand is extended the right way
3143 to match the longer operand. */
3149 }
3152 }
3153 \f
3154 /* See if ARG is an expression that is either a comparison or is performing
3155 arithmetic on comparisons. The comparisons must only be comparing
3156 two different values, which will be stored in *CVAL1 and *CVAL2; if
3157 they are nonzero it means that some operands have already been found.
3158 No variables may be used anywhere else in the expression except in the
3159 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3160 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3162 If this is true, return 1. Otherwise, return zero. */
3164 static int
3166 {
3170 /* We can handle some of the tcc_expression cases here. */
3180 {
3181 /* If we've already found a CVAL1 or CVAL2, this expression is
3182 two complex to handle. */
3188 }
3191 {
3214 /* First see if we can handle the first operand, then the second. For
3215 the second operand, we know *CVAL1 can't be zero. It must be that
3216 one side of the comparison is each of the values; test for the
3217 case where this isn't true by failing if the two operands
3218 are the same. */
3227 ;
3231 ;
3232 else
3236 ;
3240 ;
3241 else
3248 }
3249 }
3250 \f
3251 /* ARG is a tree that is known to contain just arithmetic operations and
3252 comparisons. Evaluate the operations in the tree substituting NEW0 for
3253 any occurrence of OLD0 as an operand of a comparison and likewise for
3254 NEW1 and OLD1. */
3256 static tree
3259 {
3264 /* We can handle some of the tcc_expression cases here. */
3272 {
3287 {
3306 }
3307 /* Fall through - ??? */
3310 {
3314 /* We need to check both for exact equality and tree equality. The
3315 former will be true if the operand has a side-effect. In that
3316 case, we know the operand occurred exactly once. */
3329 }
3333 }
3334 }
3335 \f
3336 /* Return a tree for the case when the result of an expression is RESULT
3337 converted to TYPE and OMITTED was previously an operand of the expression
3338 but is now not needed (e.g., we folded OMITTED * 0).
3340 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3341 the conversion of RESULT to TYPE. */
3343 tree
3345 {
3348 /* If the resulting operand is an empty statement, just return the omitted
3349 statement casted to void. */
3359 }
3361 /* Return a tree for the case when the result of an expression is RESULT
3362 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3363 of the expression but are now not needed.
3365 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3366 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3367 evaluated before OMITTED2. Otherwise, if neither has side effects,
3368 just do the conversion of RESULT to TYPE. */
3370 tree
3373 {
3382 }
3384 \f
3385 /* Return a simplified tree node for the truth-negation of ARG. This
3386 never alters ARG itself. We assume that ARG is an operation that
3387 returns a truth value (0 or 1).
3389 FIXME: one would think we would fold the result, but it causes
3390 problems with the dominator optimizer. */
3392 static tree
3394 {
3399 /* If this is a comparison, we can simply invert it, except for
3400 floating-point non-equality comparisons, in which case we just
3401 enclose a TRUTH_NOT_EXPR around what we have. */
3404 {
3407 && flag_trapping_math
3418 }
3421 {
3440 /* Here we can invert either operand. We invert the first operand
3441 unless the second operand is a TRUTH_NOT_EXPR in which case our
3442 result is the XOR of the first operand with the inside of the
3443 negation of the second operand. */
3448 else
3471 {
3478 /* A COND_EXPR may have a throw as one operand, which
3479 then has void type. Just leave void operands
3480 as they are. */
3486 }
3498 CASE_CONVERT:
3502 /* ... fall through ... */
3524 }
3525 }
3527 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3528 assume that ARG is an operation that returns a truth value (0 or 1
3529 for scalars, 0 or -1 for vectors). Return the folded expression if
3530 folding is successful. Otherwise, return NULL_TREE. */
3532 static tree
3534 {
3537 ? BIT_NOT_EXPR
3540 }
3542 /* Return a simplified tree node for the truth-negation of ARG. This
3543 never alters ARG itself. We assume that ARG is an operation that
3544 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3546 tree
3548 {
3554 ? BIT_NOT_EXPR
3557 }
3559 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3560 operands are another bit-wise operation with a common input. If so,
3561 distribute the bit operations to save an operation and possibly two if
3562 constants are involved. For example, convert
3563 (A | B) & (A | C) into A | (B & C)
3564 Further simplification will occur if B and C are constants.
3566 If this optimization cannot be done, 0 will be returned. */
3568 static tree
3571 {
3572 tree common;
3582 {
3586 }
3588 {
3592 }
3594 {
3598 }
3600 {
3604 }
3605 else
3613 }
3615 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3616 with code CODE. This optimization is unsafe. */
3617 static tree
3620 {
3624 /* (A / C) +- (B / C) -> (A +- B) / C. */
3634 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3639 {
3651 }
3654 }
3655 \f
3656 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3657 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3659 static tree
3662 {
3666 {
3673 }
3687 }
3689 /* Optimize a bit-field compare.
3691 There are two cases: First is a compare against a constant and the
3692 second is a comparison of two items where the fields are at the same
3693 bit position relative to the start of a chunk (byte, halfword, word)
3694 large enough to contain it. In these cases we can avoid the shift
3695 implicit in bitfield extractions.
3697 For constants, we emit a compare of the shifted constant with the
3698 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3699 compared. For two fields at the same position, we do the ANDs with the
3700 similar mask and compare the result of the ANDs.
3702 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3703 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3704 are the left and right operands of the comparison, respectively.
3706 If the optimization described above can be done, we return the resulting
3707 tree. Otherwise we return zero. */
3709 static tree
3712 {
3715 tree unsigned_type;
3721 tree mask;
3722 tree offset;
3724 /* Get all the information about the extractions being done. If the bit size
3725 if the same as the size of the underlying object, we aren't doing an
3726 extraction at all and so can do nothing. We also don't want to
3727 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3728 then will no longer be able to replace it. */
3736 {
3737 /* If this is not a constant, we can only do something if bit positions,
3738 sizes, and signedness are the same. */
3746 }
3748 /* See if we can find a mode to refer to this field. We should be able to,
3749 but fail if we can't. */
3758 /* Set signed and unsigned types of the precision of this mode for the
3759 shifts below. */
3762 /* Compute the bit position and size for the new reference and our offset
3763 within it. If the new reference is the same size as the original, we
3764 won't optimize anything, so return zero. */
3774 /* Make the mask to be used against the extracted field. */
3781 /* If not comparing with constant, just rework the comparison
3782 and return. */
3786 unsigned_type,
3789 mask),
3792 unsigned_type,
3795 mask));
3797 /* Otherwise, we are handling the constant case. See if the constant is too
3798 big for the field. Warn and return a tree of for 0 (false) if so. We do
3799 this not only for its own sake, but to avoid having to test for this
3800 error case below. If we didn't, we might generate wrong code.
3802 For unsigned fields, the constant shifted right by the field length should
3803 be all zero. For signed fields, the high-order bits should agree with
3804 the sign bit. */
3807 {
3809 {
3813 }
3814 }
3815 else
3816 {
3819 {
3823 }
3824 }
3826 /* Single-bit compares should always be against zero. */
3828 {
3831 }
3833 /* Make a new bitfield reference, shift the constant over the
3834 appropriate number of bits and mask it with the computed mask
3835 (in case this was a signed field). If we changed it, make a new one. */
3842 mask);
3847 }
3848 \f
3849 /* Subroutine for fold_truth_andor_1: decode a field reference.
3851 If EXP is a comparison reference, we return the innermost reference.
3853 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3854 set to the starting bit number.
3856 If the innermost field can be completely contained in a mode-sized
3857 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3859 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3860 otherwise it is not changed.
3862 *PUNSIGNEDP is set to the signedness of the field.
3864 *PMASK is set to the mask used. This is either contained in a
3865 BIT_AND_EXPR or derived from the width of the field.
3867 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3869 Return 0 if this is not a component reference or is one that we can't
3870 do anything with. */
3872 static tree
3877 {
3881 tree unsigned_type;
3884 /* All the optimizations using this function assume integer fields.
3885 There are problems with FP fields since the type_for_size call
3886 below can fail for, e.g., XFmode. */
3890 /* We are interested in the bare arrangement of bits, so strip everything
3891 that doesn't affect the machine mode. However, record the type of the
3892 outermost expression if it may matter below. */
3899 {
3905 }
3914 /* If the number of bits in the reference is the same as the bitsize of
3915 the outer type, then the outer type gives the signedness. Otherwise
3916 (in case of a small bitfield) the signedness is unchanged. */
3920 /* Compute the mask to access the bitfield. */
3929 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3937 }
3939 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
3940 bit positions and MASK is SIGNED. */
3942 static int
3944 {
3948 /* If this function returns true when the type of the mask is
3949 UNSIGNED, then there will be errors. In particular see
3950 gcc.c-torture/execute/990326-1.c. There does not appear to be
3951 any documentation paper trail as to why this is so. But the pre
3952 wide-int worked with that restriction and it has been preserved
3953 here. */
3958 }
3960 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3961 represents the sign bit of EXP's type. If EXP represents a sign
3962 or zero extension, also test VAL against the unextended type.
3963 The return value is the (sub)expression whose sign bit is VAL,
3964 or NULL_TREE otherwise. */
3966 tree
3968 {
3970 tree t;
3972 /* Tree EXP must have an integral type. */
3977 /* Tree VAL must be an integer constant. */
3986 /* Handle extension from a narrower type. */
3992 }
3994 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
3995 to be evaluated unconditionally. */
3997 static int
3999 {
4000 /* Strip any conversions that don't change the machine mode. */
4009 /* Don't regard global variables as simple. They may be
4010 allocated in ways unknown to the compiler (shared memory,
4011 #pragma weak, etc). */
4014 /* Weakrefs are not safe to be read, since they can be NULL.
4015 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4016 have DECL_WEAK flag set. */
4018 /* Loading a static variable is unduly expensive, but global
4019 registers aren't expensive. */
4021 }
4023 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4024 to be evaluated unconditionally.
4025 I addition to simple_operand_p, we assume that comparisons, conversions,
4026 and logic-not operations are simple, if their operands are simple, too. */
4028 static bool
4030 {
4050 }
4052 \f
4053 /* The following functions are subroutines to fold_range_test and allow it to
4054 try to change a logical combination of comparisons into a range test.
4056 For example, both
4057 X == 2 || X == 3 || X == 4 || X == 5
4058 and
4059 X >= 2 && X <= 5
4060 are converted to
4061 (unsigned) (X - 2) <= 3
4063 We describe each set of comparisons as being either inside or outside
4064 a range, using a variable named like IN_P, and then describe the
4065 range with a lower and upper bound. If one of the bounds is omitted,
4066 it represents either the highest or lowest value of the type.
4068 In the comments below, we represent a range by two numbers in brackets
4069 preceded by a "+" to designate being inside that range, or a "-" to
4070 designate being outside that range, so the condition can be inverted by
4071 flipping the prefix. An omitted bound is represented by a "-". For
4072 example, "- [-, 10]" means being outside the range starting at the lowest
4073 possible value and ending at 10, in other words, being greater than 10.
4074 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4075 always false.
4077 We set up things so that the missing bounds are handled in a consistent
4078 manner so neither a missing bound nor "true" and "false" need to be
4079 handled using a special case. */
4081 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4082 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4083 and UPPER1_P are nonzero if the respective argument is an upper bound
4084 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4085 must be specified for a comparison. ARG1 will be converted to ARG0's
4086 type if both are specified. */
4088 static tree
4091 {
4092 tree tem;
4096 /* If neither arg represents infinity, do the normal operation.
4097 Else, if not a comparison, return infinity. Else handle the special
4098 comparison rules. Note that most of the cases below won't occur, but
4099 are handled for consistency. */
4102 {
4107 }
4112 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4113 for neither. In real maths, we cannot assume open ended ranges are
4114 the same. But, this is computer arithmetic, where numbers are finite.
4115 We can therefore make the transformation of any unbounded range with
4116 the value Z, Z being greater than any representable number. This permits
4117 us to treat unbounded ranges as equal. */
4121 {
4142 }
4145 }
4146 \f
4147 /* Helper routine for make_range. Perform one step for it, return
4148 new expression if the loop should continue or NULL_TREE if it should
4149 stop. */
4151 tree
4155 {
4161 {
4163 /* We can only do something if the range is testing for zero. */
4172 /* We can only do something if the range is testing for zero
4173 and if the second operand is an integer constant. Note that
4174 saying something is "in" the range we make is done by
4175 complementing IN_P since it will set in the initial case of
4176 being not equal to zero; "out" is leaving it alone. */
4183 {
4204 }
4206 /* If this is an unsigned comparison, we also know that EXP is
4207 greater than or equal to zero. We base the range tests we make
4208 on that fact, so we record it here so we can parse existing
4209 range tests. We test arg0_type since often the return type
4210 of, e.g. EQ_EXPR, is boolean. */
4212 {
4216 NULL_TREE))
4221 /* If the high bound is missing, but we have a nonzero low
4222 bound, reverse the range so it goes from zero to the low bound
4223 minus 1. */
4225 {
4230 }
4231 }
4239 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4240 low and high are non-NULL, then normalize will DTRT. */
4243 {
4248 }
4250 /* (-x) IN [a,b] -> x in [-b, -a] */
4262 /* ~ X -> -X - 1 */
4271 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4272 move a constant to the other side. */
4277 /* If EXP is signed, any overflow in the computation is undefined,
4278 so we don't worry about it so long as our computations on
4279 the bounds don't overflow. For unsigned, overflow is defined
4280 and this is exactly the right thing. */
4292 normalize:
4293 /* Check for an unsigned range which has wrapped around the maximum
4294 value thus making n_high < n_low, and normalize it. */
4296 {
4302 /* If the range is of the form +/- [ x+1, x ], we won't
4303 be able to normalize it. But then, it represents the
4304 whole range or the empty set, so make it
4305 +/- [ -, - ]. */
4309 else
4311 }
4312 else
4320 CASE_CONVERT:
4338 /* If we're converting arg0 from an unsigned type, to exp,
4339 a signed type, we will be doing the comparison as unsigned.
4340 The tests above have already verified that LOW and HIGH
4341 are both positive.
4343 So we have to ensure that we will handle large unsigned
4344 values the same way that the current signed bounds treat
4345 negative values. */
4348 {
4349 tree high_positive;
4350 tree equiv_type;
4351 /* For fixed-point modes, we need to pass the saturating flag
4352 as the 2nd parameter. */
4354 equiv_type
4357 else
4358 equiv_type
4361 /* A range without an upper bound is, naturally, unbounded.
4362 Since convert would have cropped a very large value, use
4363 the max value for the destination type. */
4364 high_positive
4371 high_positive),
4374 /* If the low bound is specified, "and" the range with the
4375 range for which the original unsigned value will be
4376 positive. */
4378 {
4381 integer_zero_node),
4382 high_positive))
4386 }
4387 else
4388 {
4389 /* Otherwise, "or" the range with the range of the input
4390 that will be interpreted as negative. */
4393 integer_zero_node),
4394 high_positive))
4398 }
4399 }
4408 }
4409 }
4411 /* Given EXP, a logical expression, set the range it is testing into
4412 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4413 actually being tested. *PLOW and *PHIGH will be made of the same
4414 type as the returned expression. If EXP is not a comparison, we
4415 will most likely not be returning a useful value and range. Set
4416 *STRICT_OVERFLOW_P to true if the return value is only valid
4417 because signed overflow is undefined; otherwise, do not change
4418 *STRICT_OVERFLOW_P. */
4420 tree
4423 {
4431 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4432 and see if we can refine the range. Some of the cases below may not
4433 happen, but it doesn't seem worth worrying about this. We "continue"
4434 the outer loop when we've changed something; otherwise we "break"
4435 the switch, which will "break" the while. */
4441 {
4447 {
4455 }
4464 }
4466 /* If EXP is a constant, we can evaluate whether this is true or false. */
4468 {
4475 }
4479 }
4480 \f
4481 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4482 type, TYPE, return an expression to test if EXP is in (or out of, depending
4483 on IN_P) the range. Return 0 if the test couldn't be created. */
4485 tree
4488 {
4491 /* Disable this optimization for function pointer expressions
4492 on targets that require function pointer canonicalization. */
4499 {
4505 }
4523 {
4525 {
4529 }
4531 }
4533 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4535 {
4539 {
4541 {
4544 etype
4546 else
4549 }
4552 }
4553 }
4555 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4556 This requires wrap-around arithmetics for the type of the expression.
4557 First make sure that arithmetics in this type is valid, then make sure
4558 that it wraps around. */
4564 {
4567 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4568 for the type in question, as we rely on this here. */
4578 else
4580 }
4590 {
4592 {
4597 }
4599 }
4607 }
4608 \f
4609 /* Return the predecessor of VAL in its type, handling the infinite case. */
4611 static tree
4613 {
4619 else
4622 }
4624 /* Return the successor of VAL in its type, handling the infinite case. */
4626 static tree
4628 {
4634 else
4637 }
4639 /* Given two ranges, see if we can merge them into one. Return 1 if we
4640 can, 0 if we can't. Set the output range into the specified parameters. */
4642 bool
4645 {
4649 tree tem;
4659 /* Make range 0 be the range that starts first, or ends last if they
4660 start at the same value. Swap them if it isn't. */
4663 || (lowequal
4666 {
4670 }
4672 /* Now flag two cases, whether the ranges are disjoint or whether the
4673 second range is totally subsumed in the first. Note that the tests
4674 below are simplified by the ones above. */
4680 /* We now have four cases, depending on whether we are including or
4681 excluding the two ranges. */
4683 {
4684 /* If they don't overlap, the result is false. If the second range
4685 is a subset it is the result. Otherwise, the range is from the start
4686 of the second to the end of the first. */
4691 else
4693 }
4696 {
4697 /* If they don't overlap, the result is the first range. If they are
4698 equal, the result is false. If the second range is a subset of the
4699 first, and the ranges begin at the same place, we go from just after
4700 the end of the second range to the end of the first. If the second
4701 range is not a subset of the first, or if it is a subset and both
4702 ranges end at the same place, the range starts at the start of the
4703 first range and ends just before the second range.
4704 Otherwise, we can't describe this as a single range. */
4710 {
4715 {
4716 /* We are in the weird situation where high0 > high1 but
4717 high1 has no successor. Punt. */
4719 }
4720 }
4722 {
4727 {
4728 /* low0 < low1 but low1 has no predecessor. Punt. */
4730 }
4731 }
4732 else
4734 }
4737 {
4738 /* If they don't overlap, the result is the second range. If the second
4739 is a subset of the first, the result is false. Otherwise,
4740 the range starts just after the first range and ends at the
4741 end of the second. */
4746 else
4747 {
4752 {
4753 /* high1 > high0 but high0 has no successor. Punt. */
4755 }
4756 }
4757 }
4759 else
4760 {
4761 /* The case where we are excluding both ranges. Here the complex case
4762 is if they don't overlap. In that case, the only time we have a
4763 range is if they are adjacent. If the second is a subset of the
4764 first, the result is the first. Otherwise, the range to exclude
4765 starts at the beginning of the first range and ends at the end of the
4766 second. */
4768 {
4773 else
4774 {
4775 /* Canonicalize - [min, x] into - [-, x]. */
4778 {
4783 /* FALLTHROUGH */
4796 }
4798 /* Canonicalize - [x, max] into - [x, -]. */
4801 {
4806 /* FALLTHROUGH */
4822 }
4824 /* The ranges might be also adjacent between the maximum and
4825 minimum values of the given type. For
4826 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4827 return + [x + 1, y - 1]. */
4829 {
4836 }
4837 else
4839 }
4840 }
4843 else
4845 }
4849 }
4850 \f
4852 /* Subroutine of fold, looking inside expressions of the form
4853 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4854 of the COND_EXPR. This function is being used also to optimize
4855 A op B ? C : A, by reversing the comparison first.
4857 Return a folded expression whose code is not a COND_EXPR
4858 anymore, or NULL_TREE if no folding opportunity is found. */
4860 static tree
4863 {
4868 tree tem;
4873 /* If we have A op 0 ? A : -A, consider applying the following
4874 transformations:
4876 A == 0? A : -A same as -A
4877 A != 0? A : -A same as A
4878 A >= 0? A : -A same as abs (A)
4879 A > 0? A : -A same as abs (A)
4880 A <= 0? A : -A same as -abs (A)
4881 A < 0? A : -A same as -abs (A)
4883 None of these transformations work for modes with signed
4884 zeros. If A is +/-0, the first two transformations will
4885 change the sign of the result (from +0 to -0, or vice
4886 versa). The last four will fix the sign of the result,
4887 even though the original expressions could be positive or
4888 negative, depending on the sign of A.
4890 Note that all these transformations are correct if A is
4891 NaN, since the two alternatives (A and -A) are also NaNs. */
4898 /* In the case that A is of the form X-Y, '-A' (arg2) may
4899 have already been folded to Y-X, check for that. */
4907 {
4921 /* Fall through. */
4943 }
4945 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4946 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4947 both transformations are correct when A is NaN: A != 0
4948 is then true, and A == 0 is false. */
4952 {
4957 }
4959 /* Try some transformations of A op B ? A : B.
4961 A == B? A : B same as B
4962 A != B? A : B same as A
4963 A >= B? A : B same as max (A, B)
4964 A > B? A : B same as max (B, A)
4965 A <= B? A : B same as min (A, B)
4966 A < B? A : B same as min (B, A)
4968 As above, these transformations don't work in the presence
4969 of signed zeros. For example, if A and B are zeros of
4970 opposite sign, the first two transformations will change
4971 the sign of the result. In the last four, the original
4972 expressions give different results for (A=+0, B=-0) and
4973 (A=-0, B=+0), but the transformed expressions do not.
4975 The first two transformations are correct if either A or B
4976 is a NaN. In the first transformation, the condition will
4977 be false, and B will indeed be chosen. In the case of the
4978 second transformation, the condition A != B will be true,
4979 and A will be chosen.
4981 The conversions to max() and min() are not correct if B is
4982 a number and A is not. The conditions in the original
4983 expressions will be false, so all four give B. The min()
4984 and max() versions would give a NaN instead. */
4987 /* Avoid these transformations if the COND_EXPR may be used
4988 as an lvalue in the C++ front-end. PR c++/19199. */
4989 && (in_gimple_form
4995 {
5000 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
5002 {
5006 }
5009 {
5018 /* In C++ a ?: expression can be an lvalue, so put the
5019 operand which will be used if they are equal first
5020 so that we can convert this back to the
5021 corresponding COND_EXPR. */
5023 {
5032 }
5039 {
5048 }
5063 }
5064 }
5066 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5067 we might still be able to simplify this. For example,
5068 if C1 is one less or one more than C2, this might have started
5069 out as a MIN or MAX and been transformed by this function.
5070 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5076 {
5080 /* We can replace A with C1 in this case. */
5085 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
5086 MIN_EXPR, to preserve the signedness of the comparison. */
5088 OEP_ONLY_CONST)
5092 OEP_ONLY_CONST))
5093 {
5096 arg2));
5099 }
5103 /* If C1 is C2 - 1, this is min(A, C2), with the same care
5104 as above. */
5106 OEP_ONLY_CONST)
5110 OEP_ONLY_CONST))
5111 {
5114 arg2));
5117 }
5121 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
5122 MAX_EXPR, to preserve the signedness of the comparison. */
5124 OEP_ONLY_CONST)
5128 OEP_ONLY_CONST))
5129 {
5132 arg2));
5134 }
5138 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
5140 OEP_ONLY_CONST)
5144 OEP_ONLY_CONST))
5145 {
5148 arg2));
5150 }
5156 }
5159 }
5162 \f
5163 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5164 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5165 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5166 false) >= 2)
5167 #endif
5169 /* EXP is some logical combination of boolean tests. See if we can
5170 merge it into some range test. Return the new tree if so. */
5172 static tree
5175 {
5191 /* If this is an OR operation, invert both sides; we will invert
5192 again at the end. */
5196 /* If both expressions are the same, if we can merge the ranges, and we
5197 can build the range test, return it or it inverted. If one of the
5198 ranges is always true or always false, consider it to be the same
5199 expression as the other. */
5207 {
5211 }
5213 /* On machines where the branch cost is expensive, if this is a
5214 short-circuited branch and the underlying object on both sides
5215 is the same, make a non-short-circuit operation. */
5221 {
5222 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5223 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5224 which cases we can't do this. */
5232 {
5241 {
5244 WARN_STRICT_OVERFLOW_COMPARISON);
5248 }
5249 }
5250 }
5253 }
5254 \f
5255 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5256 bit value. Arrange things so the extra bits will be set to zero if and
5257 only if C is signed-extended to its full width. If MASK is nonzero,
5258 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5260 static tree
5262 {
5265 tree temp;
5270 /* We work by getting just the sign bit into the low-order bit, then
5271 into the high-order bit, then sign-extend. We then XOR that value
5272 with C. */
5275 /* We must use a signed type in order to get an arithmetic right shift.
5276 However, we must also avoid introducing accidental overflows, so that
5277 a subsequent call to integer_zerop will work. Hence we must
5278 do the type conversion here. At this point, the constant is either
5279 zero or one, and the conversion to a signed type can never overflow.
5280 We could get an overflow if this conversion is done anywhere else. */
5289 /* If necessary, convert the type back to match the type of C. */
5294 }
5295 \f
5296 /* For an expression that has the form
5297 (A && B) || ~B
5298 or
5299 (A || B) && ~B,
5300 we can drop one of the inner expressions and simplify to
5301 A || ~B
5302 or
5303 A && ~B
5304 LOC is the location of the resulting expression. OP is the inner
5305 logical operation; the left-hand side in the examples above, while CMPOP
5306 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5307 removing a condition that guards another, as in
5308 (A != NULL && A->...) || A == NULL
5309 which we must not transform. If RHS_ONLY is true, only eliminate the
5310 right-most operand of the inner logical operation. */
5312 static tree
5315 {
5333 {
5336 {
5339 }
5340 }
5342 {
5345 {
5348 }
5349 }
5364 }
5366 /* Find ways of folding logical expressions of LHS and RHS:
5367 Try to merge two comparisons to the same innermost item.
5368 Look for range tests like "ch >= '0' && ch <= '9'".
5369 Look for combinations of simple terms on machines with expensive branches
5370 and evaluate the RHS unconditionally.
5372 For example, if we have p->a == 2 && p->b == 4 and we can make an
5373 object large enough to span both A and B, we can do this with a comparison
5374 against the object ANDed with the a mask.
5376 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5377 operations to do this with one comparison.
5379 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5380 function and the one above.
5382 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5383 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5385 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5386 two operands.
5388 We return the simplified tree or 0 if no optimization is possible. */
5390 static tree
5393 {
5394 /* If this is the "or" of two comparisons, we can do something if
5395 the comparisons are NE_EXPR. If this is the "and", we can do something
5396 if the comparisons are EQ_EXPR. I.e.,
5397 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5399 WANTED_CODE is this operation code. For single bit fields, we can
5400 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5401 comparison for one-bit fields. */
5421 /* Start by getting the comparison codes. Fail if anything is volatile.
5422 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5423 it were surrounded with a NE_EXPR. */
5432 {
5436 }
5439 {
5443 }
5454 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5457 {
5460 {
5465 }
5468 {
5474 }
5475 }
5480 /* If the RHS can be evaluated unconditionally and its operands are
5481 simple, it wins to evaluate the RHS unconditionally on machines
5482 with expensive branches. In this case, this isn't a comparison
5483 that can be merged. */
5490 {
5491 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5502 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5512 }
5514 /* See if the comparisons can be merged. Then get all the parameters for
5515 each side. */
5539 /* It must be true that the inner operation on the lhs of each
5540 comparison must be the same if we are to be able to do anything.
5541 Then see if we have constants. If not, the same must be true for
5542 the rhs's. */
5553 else
5556 /* If either comparison code is not correct for our logical operation,
5557 fail. However, we can convert a one-bit comparison against zero into
5558 the opposite comparison against that bit being set in the field. */
5562 {
5564 {
5565 /* Make the left operand unsigned, since we are only interested
5566 in the value of one bit. Otherwise we are doing the wrong
5567 thing below. */
5570 }
5571 else
5573 }
5575 /* This is analogous to the code for l_const above. */
5577 {
5579 {
5582 }
5583 else
5585 }
5587 /* See if we can find a mode that contains both fields being compared on
5588 the left. If we can't, fail. Otherwise, update all constants and masks
5589 to be relative to a field of that size. */
5594 volatilep);
5604 {
5607 }
5615 {
5622 {
5626 }
5627 }
5629 {
5636 {
5640 }
5641 }
5643 /* If the right sides are not constant, do the same for it. Also,
5644 disallow this optimization if a size or signedness mismatch occurs
5645 between the left and right sides. */
5647 {
5650 /* Make sure the two fields on the right
5651 correspond to the left without being swapped. */
5659 volatilep);
5669 {
5672 }
5681 /* Make a mask that corresponds to both fields being compared.
5682 Do this for both items being compared. If the operands are the
5683 same size and the bits being compared are in the same position
5684 then we can do this by masking both and comparing the masked
5685 results. */
5689 {
5701 }
5703 /* There is still another way we can do something: If both pairs of
5704 fields being compared are adjacent, we may be able to make a wider
5705 field containing them both.
5707 Note that we still must mask the lhs/rhs expressions. Furthermore,
5708 the mask must be shifted to account for the shift done by
5709 make_bit_field_ref. */
5714 {
5715 tree type;
5729 /* Convert to the smaller type before masking out unwanted bits. */
5732 {
5734 {
5738 }
5740 {
5744 }
5745 }
5754 }
5757 }
5759 /* Handle the case of comparisons with constants. If there is something in
5760 common between the masks, those bits of the constants must be the same.
5761 If not, the condition is always false. Test for this to avoid generating
5762 incorrect code below. */
5767 {
5769 {
5772 }
5773 else
5774 {
5777 }
5778 }
5780 /* Construct the expression we will return. First get the component
5781 reference we will make. Unless the mask is all ones the width of
5782 that field, perform the mask operation. Then compare with the
5783 merged constant. */
5793 }
5794 \f
5795 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5796 constant. */
5798 static tree
5801 {
5804 tree comp_const;
5805 tree minmax_const;
5807 tree inner;
5818 /* If something does not permit us to optimize, return the original tree. */
5826 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5827 and GT_EXPR, doing the rest with recursive calls using logical
5828 simplifications. */
5830 {
5832 {
5833 tree tem
5840 }
5843 return
5845 optimize_minmax_comparison
5847 optimize_minmax_comparison
5852 /* MAX (X, 0) == 0 -> X <= 0 */
5856 /* MAX (X, 0) == 5 -> X == 5 */
5860 /* MAX (X, 0) == -1 -> false */
5864 /* MIN (X, 0) == 0 -> X >= 0 */
5868 /* MIN (X, 0) == 5 -> false */
5871 else
5872 /* MIN (X, 0) == -1 -> X == -1 */
5877 /* MAX (X, 0) > 0 -> X > 0
5878 MAX (X, 0) > 5 -> X > 5 */
5882 /* MAX (X, 0) > -1 -> true */
5886 /* MIN (X, 0) > 0 -> false
5887 MIN (X, 0) > 5 -> false */
5890 else
5891 /* MIN (X, 0) > -1 -> X > -1 */
5896 }
5897 }
5898 \f
5899 /* T is an integer expression that is being multiplied, divided, or taken a
5900 modulus (CODE says which and what kind of divide or modulus) by a
5901 constant C. See if we can eliminate that operation by folding it with
5902 other operations already in T. WIDE_TYPE, if non-null, is a type that
5903 should be used for the computation if wider than our type.
5905 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5906 (X * 2) + (Y * 4). We must, however, be assured that either the original
5907 expression would not overflow or that overflow is undefined for the type
5908 in the language in question.
5910 If we return a non-null expression, it is an equivalent form of the
5911 original computation, but need not be in the original type.
5913 We set *STRICT_OVERFLOW_P to true if the return values depends on
5914 signed overflow being undefined. Otherwise we do not change
5915 *STRICT_OVERFLOW_P. */
5917 static tree
5920 {
5921 /* To avoid exponential search depth, refuse to allow recursion past
5922 three levels. Beyond that (1) it's highly unlikely that we'll find
5923 something interesting and (2) we've probably processed it before
5924 when we built the inner expression. */
5927 tree ret;
5932 depth++;
5934 depth--;
5937 }
5939 static tree
5942 {
5953 /* Don't deal with constants of zero here; they confuse the code below. */
5963 /* Note that we need not handle conditional operations here since fold
5964 already handles those cases. So just do arithmetic here. */
5966 {
5968 /* For a constant, we can always simplify if we are a multiply
5969 or (for divide and modulus) if it is a multiple of our constant. */
5977 /* If op0 is an expression ... */
5983 /* ... and has wrapping overflow, and its type is smaller
5984 than ctype, then we cannot pass through as widening. */
5989 /* ... or this is a truncation (t is narrower than op0),
5990 then we cannot pass through this narrowing. */
5993 /* ... or signedness changes for division or modulus,
5994 then we cannot pass through this conversion. */
5998 /* ... or has undefined overflow while the converted to
5999 type has not, we cannot do the operation in the inner type
6000 as that would introduce undefined overflow. */
6006 /* Pass the constant down and see if we can make a simplification. If
6007 we can, replace this expression with the inner simplification for
6008 possible later conversion to our or some other type. */
6013 code == MULT_EXPR
6015 strict_overflow_p))))
6020 /* If widening the type changes it from signed to unsigned, then we
6021 must avoid building ABS_EXPR itself as unsigned. */
6023 {
6027 {
6030 }
6032 }
6033 /* If the constant is negative, we cannot simplify this. */
6036 /* FALLTHROUGH */
6038 /* For division and modulus, type can't be unsigned, as e.g.
6039 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6040 For signed types, even with wrapping overflow, this is fine. */
6049 /* If widening the type changes the signedness, then we can't perform
6050 this optimization as that changes the result. */
6054 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6060 {
6067 }
6071 /* If the second operand is constant, this is a multiplication
6072 or floor division, by a power of two, so we can treat it that
6073 way unless the multiplier or divisor overflows. Signed
6074 left-shift overflow is implementation-defined rather than
6075 undefined in C90, so do not convert signed left shift into
6076 multiplication. */
6079 /* const_binop may not detect overflow correctly,
6080 so check for it explicitly here. */
6084 size_one_node,
6085 op1)))
6089 ctype,
6091 t1),
6096 /* See if we can eliminate the operation on both sides. If we can, we
6097 can return a new PLUS or MINUS. If we can't, the only remaining
6098 cases where we can do anything are if the second operand is a
6099 constant. */
6105 /* If not multiplication, we can only do this if both operands
6106 are divisible by c. */
6109 {
6114 }
6116 /* If this was a subtraction, negate OP1 and set it to be an addition.
6117 This simplifies the logic below. */
6119 {
6121 /* If OP1 was not easily negatable, the constant may be OP0. */
6123 {
6126 }
6127 }
6132 /* If either OP1 or C are negative, this optimization is not safe for
6133 some of the division and remainder types while for others we need
6134 to change the code. */
6136 {
6144 }
6146 /* If it's a multiply or a division/modulus operation of a multiple
6147 of our constant, do the operation and verify it doesn't overflow. */
6150 {
6153 /* We allow the constant to overflow with wrapping semantics. */
6157 }
6158 else
6161 /* If we have an unsigned type, we cannot widen the operation since it
6162 will change the result if the original computation overflowed. */
6166 /* If we were able to eliminate our operation from the first side,
6167 apply our operation to the second side and reform the PLUS. */
6171 /* The last case is if we are a multiply. In that case, we can
6172 apply the distributive law to commute the multiply and addition
6173 if the multiplication of the constants doesn't overflow
6174 and overflow is defined. With undefined overflow
6175 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6181 op1);
6186 /* We have a special case here if we are doing something like
6187 (C * 8) % 4 since we know that's zero. */
6190 /* If the multiplication can overflow we cannot optimize this. */
6194 {
6197 }
6199 /* ... fall through ... */
6203 /* If we can extract our operation from the LHS, do so and return a
6204 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6205 do something only if the second operand is a constant. */
6219 /* If these are the same operation types, we can associate them
6220 assuming no overflow. */
6222 {
6234 }
6236 /* If these operations "cancel" each other, we have the main
6237 optimizations of this pass, which occur when either constant is a
6238 multiple of the other, in which case we replace this with either an
6239 operation or CODE or TCODE.
6241 If we have an unsigned type, we cannot do this since it will change
6242 the result if the original computation overflowed. */
6249 {
6251 {
6258 }
6260 {
6267 }
6268 }
6273 }
6276 }
6277 \f
6278 /* Return a node which has the indicated constant VALUE (either 0 or
6279 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6280 and is of the indicated TYPE. */
6282 tree
6284 {
6293 else
6295 }
6298 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6299 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6300 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6301 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6302 COND is the first argument to CODE; otherwise (as in the example
6303 given here), it is the second argument. TYPE is the type of the
6304 original expression. Return NULL_TREE if no simplification is
6305 possible. */
6307 static tree
6312 {
6322 {
6326 /* If this operand throws an expression, then it does not make
6327 sense to try to perform a logical or arithmetic operation
6328 involving it. */
6333 }
6334 else
6335 {
6340 }
6345 /* This transformation is only worthwhile if we don't have to wrap ARG
6346 in a SAVE_EXPR and the operation can be simplified without recursing
6347 on at least one of the branches once its pushed inside the COND_EXPR. */
6356 {
6360 else
6362 }
6364 {
6368 else
6370 }
6372 /* Check that we have simplified at least one of the branches. */
6377 }
6379 \f
6380 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6382 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6383 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6384 ADDEND is the same as X.
6386 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6387 and finite. The problematic cases are when X is zero, and its mode
6388 has signed zeros. In the case of rounding towards -infinity,
6389 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6390 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6392 bool
6394 {
6398 /* Don't allow the fold with -fsignaling-nans. */
6402 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6406 /* In a vector or complex, we would need to check the sign of all zeros. */
6410 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6414 /* The mode has signed zeros, and we have to honor their sign.
6415 In this situation, there is only one case we can return true for.
6416 X - 0 is the same as X unless rounding towards -infinity is
6417 supported. */
6419 }
6421 /* Subroutine of fold() that checks comparisons of built-in math
6422 functions against real constants.
6424 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6425 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6426 is the type of the result and ARG0 and ARG1 are the operands of the
6427 comparison. ARG1 must be a TREE_REAL_CST.
6429 The function returns the constant folded tree if a simplification
6430 can be made, and NULL_TREE otherwise. */
6432 static tree
6436 {
6437 REAL_VALUE_TYPE c;
6440 {
6446 {
6447 /* sqrt(x) < y is always false, if y is negative. */
6451 /* sqrt(x) > y is always true, if y is negative and we
6452 don't care about NaNs, i.e. negative values of x. */
6456 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6459 }
6461 {
6462 REAL_VALUE_TYPE c2;
6468 {
6469 /* sqrt(x) > y is x == +Inf, when y is very large. */
6474 /* sqrt(x) > y is always false, when y is very large
6475 and we don't care about infinities. */
6477 }
6479 /* sqrt(x) > c is the same as x > c*c. */
6482 }
6484 {
6485 REAL_VALUE_TYPE c2;
6491 {
6492 /* sqrt(x) < y is always true, when y is a very large
6493 value and we don't care about NaNs or Infinities. */
6497 /* sqrt(x) < y is x != +Inf when y is very large and we
6498 don't care about NaNs. */
6503 /* sqrt(x) < y is x >= 0 when y is very large and we
6504 don't care about Infinities. */
6509 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6514 dconst0)),
6517 c2)));
6518 }
6520 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6525 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6530 dconst0)),
6533 c2)));
6534 }
6535 }
6538 }
6540 /* Subroutine of fold() that optimizes comparisons against Infinities,
6541 either +Inf or -Inf.
6543 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6544 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6545 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6547 The function returns the constant folded tree if a simplification
6548 can be made, and NULL_TREE otherwise. */
6550 static tree
6553 {
6554 machine_mode mode;
6555 REAL_VALUE_TYPE max;
6556 tree temp;
6561 /* For negative infinity swap the sense of the comparison. */
6567 {
6569 /* x > +Inf is always false, if with ignore sNANs. */
6575 /* x <= +Inf is always true, if we don't case about NaNs. */
6579 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6585 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6591 /* x < +Inf is always equal to x <= DBL_MAX. */
6597 /* x != +Inf is always equal to !(x > DBL_MAX). */
6609 }
6612 }
6614 /* Subroutine of fold() that optimizes comparisons of a division by
6615 a nonzero integer constant against an integer constant, i.e.
6616 X/C1 op C2.
6618 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6619 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6620 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6622 The function returns the constant folded tree if a simplification
6623 can be made, and NULL_TREE otherwise. */
6625 static tree
6628 {
6636 /* We have to do this the hard way to detect unsigned overflow.
6637 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6643 {
6648 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6652 }
6654 {
6658 {
6677 }
6678 }
6679 else
6680 {
6681 /* A negative divisor reverses the relational operators. */
6687 {
6706 }
6707 }
6710 {
6731 {
6734 }
6739 {
6742 }
6747 {
6750 }
6755 {
6758 }
6763 }
6766 }
6769 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6770 equality/inequality test, then return a simplified form of the test
6771 using a sign testing. Otherwise return NULL. TYPE is the desired
6772 result type. */
6774 static tree
6777 tree result_type)
6778 {
6779 /* If this is testing a single bit, we can optimize the test. */
6783 {
6784 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6785 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6789 /* This is only a win if casting to a signed type is cheap,
6790 i.e. when arg00's type is not a partial mode. */
6793 {
6796 result_type,
6799 }
6800 }
6803 }
6805 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6806 equality/inequality test, then return a simplified form of
6807 the test using shifts and logical operations. Otherwise return
6808 NULL. TYPE is the desired result type. */
6810 tree
6813 {
6814 /* If this is testing a single bit, we can optimize the test. */
6818 {
6827 /* First, see if we can fold the single bit test into a sign-bit
6828 test. */
6830 result_type);
6834 /* Otherwise we have (A & C) != 0 where C is a single bit,
6835 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6836 Similarly for (A & C) == 0. */
6838 /* If INNER is a right shift of a constant and it plus BITNUM does
6839 not overflow, adjust BITNUM and INNER. */
6845 {
6848 }
6850 /* If we are going to be able to omit the AND below, we must do our
6851 operations as unsigned. If we must use the AND, we have a choice.
6852 Normally unsigned is faster, but for some machines signed is. */
6853 #ifdef LOAD_EXTEND_OP
6856 #else
6858 #endif
6874 /* Put the AND last so it can combine with more things. */
6877 /* Make sure to return the proper type. */
6881 }
6883 }
6885 /* Check whether we are allowed to reorder operands arg0 and arg1,
6886 such that the evaluation of arg1 occurs before arg0. */
6888 static bool
6890 {
6897 }
6899 /* Test whether it is preferable two swap two operands, ARG0 and
6900 ARG1, for example because ARG0 is an integer constant and ARG1
6901 isn't. If REORDER is true, only recommend swapping if we can
6902 evaluate the operands in reverse order. */
6904 bool
6906 {
6924 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6925 for commutative and comparison operators. Ensuring a canonical
6926 form allows the optimizers to find additional redundancies without
6927 having to explicitly check for both orderings. */
6933 /* Put SSA_NAMEs last. */
6939 /* Put variables last. */
6946 }
6948 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6949 ARG0 is extended to a wider type. */
6951 static tree
6954 {
6956 tree arg1_unw;
6965 /* Disable this optimization if we're casting a function pointer
6966 type on targets that require function pointer canonicalization. */
6977 /* If possible, express the comparison in the shorter mode. */
6997 /* If we are comparing with the integer that does not fit into the range
6998 of the shorter type, the result is known. */
7009 {
7036 }
7039 }
7041 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
7042 ARG0 just the signedness is changed. */
7044 static tree
7047 {
7048 tree arg0_inner;
7058 /* Disable this optimization if we're casting a function pointer
7059 type on targets that require function pointer canonicalization. */
7084 else
7088 }
7091 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7092 means A >= Y && A != MAX, but in this case we know that
7093 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7095 static tree
7097 {
7104 else
7113 {
7116 }
7118 {
7121 }
7122 else
7129 {
7130 /* Convert the pointer types into integer before taking the difference. */
7134 }
7135 else
7142 }
7144 /* Fold a sum or difference of at least one multiplication.
7145 Returns the folded tree or NULL if no simplification could be made. */
7147 static tree
7150 {
7154 /* (A * C) +- (B * C) -> (A+-B) * C.
7155 (A * C) +- A -> A * (C+-1).
7156 We are most concerned about the case where C is a constant,
7157 but other combinations show up during loop reduction. Since
7158 it is not difficult, try all four possibilities. */
7161 {
7164 }
7166 {
7169 }
7170 else
7171 {
7172 /* We cannot generate constant 1 for fract. */
7177 }
7179 {
7182 }
7184 {
7186 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7187 the purpose of this canonicalization. */
7191 {
7194 }
7195 else
7197 }
7198 else
7199 {
7200 /* We cannot generate constant 1 for fract. */
7205 }
7217 /* No identical multiplicands; see if we can find a common
7218 power-of-two factor in non-power-of-two multiplies. This
7219 can help in multi-dimensional array access. */
7222 {
7225 tree maybe_same;
7229 /* Move min of absolute values to int11. */
7231 {
7236 }
7237 else
7241 /* The remainder should not be a constant, otherwise we
7242 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7243 increased the number of multiplications necessary. */
7245 {
7253 }
7254 }
7264 }
7266 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7267 specified by EXPR into the buffer PTR of length LEN bytes.
7268 Return the number of bytes placed in the buffer, or zero
7269 upon failure. */
7271 static int
7273 {
7287 {
7289 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7290 number of bytes. */
7294 {
7301 else
7303 }
7304 else
7309 }
7311 }
7314 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7315 specified by EXPR into the buffer PTR of length LEN bytes.
7316 Return the number of bytes placed in the buffer, or zero
7317 upon failure. */
7319 static int
7321 {
7325 FIXED_VALUE_TYPE value;
7341 }
7344 /* Subroutine of native_encode_expr. Encode the REAL_CST
7345 specified by EXPR into the buffer PTR of length LEN bytes.
7346 Return the number of bytes placed in the buffer, or zero
7347 upon failure. */
7349 static int
7351 {
7357 /* There are always 32 bits in each long, no matter the size of
7358 the hosts long. We handle floating point representations with
7359 up to 192 bits. */
7373 {
7378 {
7385 else
7387 }
7388 else
7394 }
7396 }
7398 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7399 specified by EXPR into the buffer PTR of length LEN bytes.
7400 Return the number of bytes placed in the buffer, or zero
7401 upon failure. */
7403 static int
7405 {
7407 tree part;
7422 }
7425 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7426 specified by EXPR into the buffer PTR of length LEN bytes.
7427 Return the number of bytes placed in the buffer, or zero
7428 upon failure. */
7430 static int
7432 {
7442 {
7444 {
7447 }
7458 }
7460 }
7463 /* Subroutine of native_encode_expr. Encode the STRING_CST
7464 specified by EXPR into the buffer PTR of length LEN bytes.
7465 Return the number of bytes placed in the buffer, or zero
7466 upon failure. */
7468 static int
7470 {
7472 HOST_WIDE_INT total_bytes;
7486 {
7489 {
7492 }
7495 }
7496 else
7499 }
7502 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7503 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7504 buffer PTR of length LEN bytes. If OFF is not -1 then start
7505 the encoding at byte offset OFF and encode at most LEN bytes.
7506 Return the number of bytes placed in the buffer, or zero upon failure. */
7508 int
7510 {
7512 {
7533 }
7534 }
7537 /* Subroutine of native_interpret_expr. Interpret the contents of
7538 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7539 If the buffer cannot be interpreted, return NULL_TREE. */
7541 static tree
7543 {
7553 }
7556 /* Subroutine of native_interpret_expr. Interpret the contents of
7557 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7558 If the buffer cannot be interpreted, return NULL_TREE. */
7560 static tree
7562 {
7564 double_int result;
7565 FIXED_VALUE_TYPE fixed_value;
7575 }
7578 /* Subroutine of native_interpret_expr. Interpret the contents of
7579 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7580 If the buffer cannot be interpreted, return NULL_TREE. */
7582 static tree
7584 {
7589 /* There are always 32 bits in each long, no matter the size of
7590 the hosts long. We handle floating point representations with
7591 up to 192 bits. */
7592 REAL_VALUE_TYPE r;
7603 {
7606 {
7613 else
7615 }
7616 else
7621 }
7625 }
7628 /* Subroutine of native_interpret_expr. Interpret the contents of
7629 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7630 If the buffer cannot be interpreted, return NULL_TREE. */
7632 static tree
7634 {
7649 }
7652 /* Subroutine of native_interpret_expr. Interpret the contents of
7653 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7654 If the buffer cannot be interpreted, return NULL_TREE. */
7656 static tree
7658 {
7671 {
7676 }
7678 }
7681 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7682 the buffer PTR of length LEN as a constant of type TYPE. For
7683 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7684 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7685 return NULL_TREE. */
7687 tree
7689 {
7691 {
7713 }
7714 }
7716 /* Returns true if we can interpret the contents of a native encoding
7717 as TYPE. */
7719 static bool
7721 {
7723 {
7736 }
7737 }
7739 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7740 TYPE at compile-time. If we're unable to perform the conversion
7741 return NULL_TREE. */
7743 static tree
7745 {
7746 /* We support up to 512-bit values (for V8DFmode). */
7750 /* Check that the host and target are sane. */
7759 }
7761 /* Build an expression for the address of T. Folds away INDIRECT_REF
7762 to avoid confusing the gimplify process. */
7764 tree
7766 {
7767 /* The size of the object is not relevant when talking about its address. */
7772 {
7777 }
7787 {
7792 }
7793 else
7797 }
7799 /* Build an expression for the address of T. */
7801 tree
7803 {
7807 }
7809 /* Fold a unary expression of code CODE and type TYPE with operand
7810 OP0. Return the folded expression if folding is successful.
7811 Otherwise, return NULL_TREE. */
7813 tree
7815 {
7816 tree tem;
7817 tree arg0;
7825 {
7828 {
7829 /* Don't use STRIP_NOPS, because signedness of argument type
7830 matters. */
7832 }
7833 else
7834 {
7835 /* Strip any conversions that don't change the mode. This
7836 is safe for every expression, except for a comparison
7837 expression because its signedness is derived from its
7838 operands.
7840 Note that this is done as an internal manipulation within
7841 the constant folder, in order to find the simplest
7842 representation of the arguments so that their form can be
7843 studied. In any cases, the appropriate type conversions
7844 should be put back in the tree that will get out of the
7845 constant folder. */
7847 }
7850 {
7853 {
7857 }
7858 }
7859 }
7866 {
7873 {
7887 /* If this was a conversion, and all we did was to move into
7888 inside the COND_EXPR, bring it back out. But leave it if
7889 it is a conversion from integer to integer and the
7890 result precision is no wider than a word since such a
7891 conversion is cheap and may be optimized away by combine,
7892 while it couldn't if it were outside the COND_EXPR. Then return
7893 so we don't get into an infinite recursion loop taking the
7894 conversion out and then back in. */
7906 && (INTEGRAL_TYPE_P
7919 }
7920 }
7923 {
7929 CASE_CONVERT:
7933 {
7934 /* If we have (type) (a CMP b) and type is an integral type, return
7935 new expression involving the new type. Canonicalize
7936 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7937 non-integral type.
7938 Do not fold the result as that would not simplify further, also
7939 folding again results in recursions. */
7949 }
7951 /* Handle (T *)&A.B.C for A being of type T and B and C
7952 living at offset zero. This occurs frequently in
7953 C++ upcasting and then accessing the base. */
7957 {
7959 tree offset;
7960 machine_mode mode;
7965 /* If the reference was to a (constant) zero offset, we can use
7966 the address of the base if it has the same base type
7967 as the result type and the pointer type is unqualified. */
7974 }
7978 /* Detect assigning a bitfield. */
7980 && DECL_BIT_FIELD
7982 {
7983 /* Don't leave an assignment inside a conversion
7984 unless assigning a bitfield. */
7986 /* First do the assignment, then return converted constant. */
7991 }
7993 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7994 constants (if x has signed type, the sign bit cannot be set
7995 in c). This folds extension into the BIT_AND_EXPR.
7996 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7997 very likely don't have maximal range for their precision and this
7998 transformation effectively doesn't preserve non-maximal ranges. */
8002 {
8013 <= HOST_BITS_PER_WIDE_INT
8015 {
8019 cst &= HOST_WIDE_INT_M1U
8022 #ifdef LOAD_EXTEND_OP
8024 && !flag_syntax_only
8027 {
8031 }
8032 #endif
8033 }
8035 {
8040 }
8041 }
8043 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
8044 when one of the new casts will fold away. Conservatively we assume
8045 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
8052 {
8056 return fold_build_pointer_plus_loc
8058 }
8060 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
8061 of the same precision, and X is an integer type not narrower than
8062 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
8068 {
8074 }
8076 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
8077 type of X and Y (integer types only). */
8082 {
8083 /* Be careful not to introduce new overflows. */
8084 tree mult_type;
8087 else
8091 {
8098 }
8099 }
8117 /* Convert fabs((double)float) into (double)fabsf(float). */
8120 {
8126 targ0));
8127 }
8129 /* Strip sign ops from argument. */
8131 {
8136 }
8143 {
8149 }
8155 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8174 /* Note that the operand of this must be an int
8175 and its values must be 0 or 1.
8176 ("true" is a fixed value perhaps depending on the language,
8177 but we don't handle values other than 1 correctly yet.) */
8187 {
8195 }
8197 {
8202 }
8204 {
8208 {
8217 }
8218 }
8225 {
8233 }
8235 {
8239 }
8241 {
8245 {
8254 }
8255 }
8259 /* Fold *&X to X if X is an lvalue. */
8261 {
8268 }
8274 }
8277 /* If the operation was a conversion do _not_ mark a resulting constant
8278 with TREE_OVERFLOW if the original constant was not. These conversions
8279 have implementation defined behavior and retaining the TREE_OVERFLOW
8280 flag here would confuse later passes such as VRP. */
8281 tree
8284 {
8293 }
8295 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8296 operands OP0 and OP1. LOC is the location of the resulting expression.
8297 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8298 Return the folded expression if folding is successful. Otherwise,
8299 return NULL_TREE. */
8300 static tree
8303 {
8304 tree tem;
8306 /* We only do these simplifications if we are optimizing. */
8310 /* Check for things like (A || B) && (A || C). We can convert this
8311 to A || (B && C). Note that either operator can be any of the four
8312 truth and/or operations and the transformation will still be
8313 valid. Also note that we only care about order for the
8314 ANDIF and ORIF operators. If B contains side effects, this
8315 might change the truth-value of A. */
8322 {
8342 /* This case if tricky because we must either have commutative
8343 operators or else A10 must not have side-effects. */
8349 a01);
8350 }
8352 /* See if we can build a range comparison. */
8358 {
8362 }
8366 {
8370 }
8372 /* Check for the possibility of merging component references. If our
8373 lhs is another similar operation, try to merge its rhs with our
8374 rhs. Then try to merge our lhs and rhs. */
8388 {
8395 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8396 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8397 We don't want to pack more than two leafs to a non-IF AND/OR
8398 expression.
8399 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8400 equal to IF-CODE, then we don't want to add right-hand operand.
8401 If the inner right-hand side of left-hand operand has
8402 side-effects, or isn't simple, then we can't add to it,
8403 as otherwise we might destroy if-sequence. */
8406 /* Needed for sequence points to handle trappings, and
8407 side-effects. */
8409 {
8411 arg1);
8413 tem);
8414 }
8415 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8416 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8419 /* Needed for sequence points to handle trappings, and
8420 side-effects. */
8422 {
8427 }
8428 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8429 into (A OR B).
8430 For sequence point consistancy, we need to check for trapping,
8431 and side-effects. */
8435 }
8438 }
8440 /* Fold a binary expression of code CODE and type TYPE with operands
8441 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8442 Return the folded expression if folding is successful. Otherwise,
8443 return NULL_TREE. */
8445 static tree
8447 {
8454 else
8457 /* MIN (MAX (a, b), b) == b. */
8462 /* MIN (MAX (b, a), b) == b. */
8468 /* MIN (a, MAX (a, b)) == a. */
8474 /* MIN (a, MAX (b, a)) == a. */
8481 }
8483 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8484 by changing CODE to reduce the magnitude of constants involved in
8485 ARG0 of the comparison.
8486 Returns a canonicalized comparison tree if a simplification was
8487 possible, otherwise returns NULL_TREE.
8488 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8489 valid if signed overflow is undefined. */
8491 static tree
8495 {
8501 /* Match A +- CST code arg1 and CST code arg1. We can change the
8502 first form only if overflow is undefined. */
8505 /* In principle pointers also have undefined overflow behavior,
8506 but that causes problems elsewhere. */
8514 /* Identify the constant in arg0 and its sign. */
8517 else
8521 /* Overflowed constants and zero will cause problems. */
8526 /* See if we can reduce the magnitude of the constant in
8527 arg0 by changing the comparison code. */
8529 {
8530 /* CST <= arg1 -> CST-1 < arg1. */
8533 /* -CST < arg1 -> -CST-1 <= arg1. */
8536 /* CST > arg1 -> CST-1 >= arg1. */
8539 /* -CST >= arg1 -> -CST-1 > arg1. */
8542 else
8544 /* arg1 code' CST' might be more canonical. */
8546 }
8547 else
8548 {
8549 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8553 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8557 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8561 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8565 else
8568 }
8570 /* Now build the constant reduced in magnitude. But not if that
8571 would produce one outside of its types range. */
8579 /* We cannot swap the comparison here as that would cause us to
8580 endlessly recurse. */
8589 /* If swapping might yield to a more canonical form, do so. */
8592 else
8594 }
8596 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8597 overflow further. Try to decrease the magnitude of constants involved
8598 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8599 and put sole constants at the second argument position.
8600 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8602 static tree
8605 {
8606 tree t;
8611 /* Try canonicalization by simplifying arg0. */
8616 {
8620 }
8622 /* Try canonicalization by simplifying arg1 using the swapped
8623 comparison. */
8631 }
8633 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8634 space. This is used to avoid issuing overflow warnings for
8635 expressions like &p->x which can not wrap. */
8637 static bool
8639 {
8646 wide_int wi_offset;
8652 else
8668 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8669 array. */
8671 {
8672 HOST_WIDE_INT base_size;
8677 }
8680 }
8682 /* Return the HOST_WIDE_INT least significant bits of T, a sizetype
8683 kind INTEGER_CST. This makes sure to properly sign-extend the
8684 constant. */
8686 static HOST_WIDE_INT
8688 {
8694 }
8696 /* Subroutine of fold_binary. This routine performs all of the
8697 transformations that are common to the equality/inequality
8698 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8699 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8700 fold_binary should call fold_binary. Fold a comparison with
8701 tree code CODE and type TYPE with operands OP0 and OP1. Return
8702 the folded comparison or NULL_TREE. */
8704 static tree
8707 {
8717 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1. */
8719 && (equality_code
8726 {
8727 const enum tree_code
8734 /* If the constant operation overflowed this can be
8735 simplified as a comparison against INT_MAX/INT_MIN. */
8738 {
8742 /* Get the sign of the constant on the lhs if the
8743 operation were VARIABLE + CONST1. */
8747 /* The sign of the constant determines if we overflowed
8748 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8749 Canonicalize to the INT_MIN overflow by swapping the comparison
8750 if necessary. */
8754 /* We now can look at the canonicalized case
8755 VARIABLE + 1 CODE2 INT_MIN
8756 and decide on the result. */
8758 {
8762 return
8768 return
8773 }
8774 }
8775 else
8776 {
8779 "when changing X +- C1 cmp C2 to "
8781 WARN_STRICT_OVERFLOW_COMPARISON);
8783 }
8784 }
8786 /* For comparisons of pointers we can decompose it to a compile time
8787 comparison of the base objects and the offsets into the object.
8788 This requires at least one operand being an ADDR_EXPR or a
8789 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8795 {
8798 machine_mode mode;
8802 /* Get base and offset for the access. Strip ADDR_EXPR for
8803 get_inner_reference, but put it back by stripping INDIRECT_REF
8804 off the base object if possible. indirect_baseN will be true
8805 if baseN is not an address but refers to the object itself. */
8808 {
8814 else
8816 }
8818 {
8822 {
8825 }
8828 {
8833 {
8836 }
8837 }
8838 }
8842 {
8848 else
8850 }
8852 {
8856 {
8859 }
8862 {
8867 {
8870 }
8871 }
8872 }
8874 /* A local variable can never be pointed to by
8875 the default SSA name of an incoming parameter. */
8877 && indirect_base0
8880 && !indirect_base1
8885 && indirect_base1
8888 && !indirect_base0
8892 {
8897 }
8898 /* If we have equivalent bases we might be able to simplify. */
8901 {
8902 /* We can fold this expression to a constant if the non-constant
8903 offset parts are equal. */
8912 {
8918 "occur when comparing P +- C1 with "
8920 WARN_STRICT_OVERFLOW_CONDITIONAL);
8923 {
8937 }
8938 }
8939 /* We can simplify the comparison to a comparison of the variable
8940 offset parts if the constant offset parts are equal.
8941 Be careful to use signed sizetype here because otherwise we
8942 mess with array offsets in the wrong way. This is possible
8943 because pointer arithmetic is restricted to retain within an
8944 object and overflow on pointer differences is undefined as of
8945 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8947 && (equality_code
8950 {
8951 /* By converting to signed sizetype we cover middle-end pointer
8952 arithmetic which operates on unsigned pointer types of size
8953 type size and ARRAY_REF offsets which are properly sign or
8954 zero extended from their type in case it is narrower than
8955 sizetype. */
8958 else
8962 else
8969 "occur when comparing P +- C1 with "
8971 WARN_STRICT_OVERFLOW_COMPARISON);
8974 }
8975 }
8976 /* For non-equal bases we can simplify if they are addresses
8977 declarations with different addresses. */
8979 /* We know that !operand_equal_p (base0, base1, 0)
8980 because the if condition was false. But make
8981 sure two decls are not the same. */
8987 /* Watch for aliases. */
8992 {
8999 }
9000 /* For equal offsets we can simplify to a comparison of the
9001 base addresses. */
9003 && (indirect_base0
9005 && (indirect_base1
9010 {
9016 }
9017 }
9019 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
9020 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
9021 the resulting offset is smaller in absolute value than the
9022 original one and has the same sign. */
9031 {
9036 tree cst;
9038 "occur when combining constants around "
9041 /* Put the constant on the side where it doesn't overflow and is
9042 of lower absolute value and of same sign than before. */
9049 {
9052 variable1,
9056 }
9064 {
9070 variable2);
9071 }
9072 }
9079 {
9087 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
9094 {
9095 REAL_VALUE_TYPE cst;
9098 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
9099 /* a CMP (-0) -> a CMP 0 */
9104 /* x != NaN is always true, other ops are always false. */
9107 {
9110 }
9112 /* Fold comparisons against infinity. */
9115 {
9119 }
9120 }
9122 /* If this is a comparison of a real constant with a PLUS_EXPR
9123 or a MINUS_EXPR of a real constant, we can convert it into a
9124 comparison with a revised real constant as long as no overflow
9125 occurs when unsafe_math_optimizations are enabled. */
9137 /* Likewise, we can simplify a comparison of a real constant with
9138 a MINUS_EXPR whose first operand is also a real constant, i.e.
9139 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9140 floating-point types only if -fassociative-math is set. */
9146 arg1))
9151 /* Fold comparisons against built-in math functions. */
9153 && flag_unsafe_math_optimizations
9155 {
9159 {
9163 }
9164 }
9165 }
9169 {
9170 /* If we are widening one operand of an integer comparison,
9171 see if the other operand is similarly being widened. Perhaps we
9172 can do the comparison in the narrower type. */
9177 /* Or if we are changing signedness. */
9181 }
9183 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9184 constant, we can simplify it. */
9189 {
9193 }
9195 /* If we are comparing an expression that just has comparisons
9196 of two integer values, arithmetic expressions of those comparisons,
9197 and constants, we can simplify it. There are only three cases
9198 to check: the two values can either be equal, the first can be
9199 greater, or the second can be greater. Fold the expression for
9200 those three values. Since each value must be 0 or 1, we have
9201 eight possibilities, each of which corresponds to the constant 0
9202 or 1 or one of the six possible comparisons.
9204 This handles common cases like (a > b) == 0 but also handles
9205 expressions like ((x > y) - (y > x)) > 0, which supposedly
9206 occur in macroized code. */
9209 {
9214 /* Don't handle degenerate cases here; they should already
9215 have been handled anyway. */
9224 {
9228 /* We can't just pass T to eval_subst in case cval1 or cval2
9229 was the same as ARG1. */
9231 tree high_result
9235 arg1);
9236 tree equal_result
9240 arg1);
9241 tree low_result
9245 arg1);
9247 /* All three of these results should be 0 or 1. Confirm they are.
9248 Then use those values to select the proper code to use. */
9253 {
9254 /* Make a 3-bit mask with the high-order bit being the
9255 value for `>', the next for '=', and the low for '<'. */
9259 {
9261 /* Always false. */
9282 /* Always true. */
9284 }
9287 {
9291 }
9293 }
9294 }
9295 }
9297 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9298 into a single range test. */
9306 {
9310 }
9313 }
9316 /* Subroutine of fold_binary. Optimize complex multiplications of the
9317 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9318 argument EXPR represents the expression "z" of type TYPE. */
9320 static tree
9322 {
9327 {
9330 }
9332 {
9335 }
9336 else
9337 {
9341 }
9350 }
9353 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
9354 CONSTRUCTOR ARG into array ELTS and return true if successful. */
9356 static bool
9358 {
9362 {
9365 }
9367 {
9373 else
9375 }
9376 else
9382 }
9384 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9385 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9386 NULL_TREE otherwise. */
9388 static tree
9390 {
9407 {
9411 }
9414 {
9420 }
9421 else
9423 }
9425 /* Try to fold a pointer difference of type TYPE two address expressions of
9426 array references AREF0 and AREF1 using location LOC. Return a
9427 simplified expression for the difference or NULL_TREE. */
9429 static tree
9432 {
9437 /* If the bases are array references as well, recurse. If the bases
9438 are pointer indirections compute the difference of the pointers.
9439 If the bases are equal, we are set. */
9442 && (base_offset
9450 {
9456 base_offset,
9459 }
9461 }
9463 /* If the real or vector real constant CST of type TYPE has an exact
9464 inverse, return it, else return NULL. */
9466 tree
9468 {
9469 REAL_VALUE_TYPE r;
9471 machine_mode mode;
9475 {
9491 {
9496 }
9502 }
9503 }
9505 /* Mask out the tz least significant bits of X of type TYPE where
9506 tz is the number of trailing zeroes in Y. */
9507 static wide_int
9509 {
9514 }
9516 /* Return true when T is an address and is known to be nonzero.
9517 For floating point we further ensure that T is not denormal.
9518 Similar logic is present in nonzero_address in rtlanal.h.
9520 If the return value is based on the assumption that signed overflow
9521 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9522 change *STRICT_OVERFLOW_P. */
9524 static bool
9526 {
9530 /* Doing something useful for floating point would need more work. */
9536 {
9539 strict_overflow_p);
9545 strict_overflow_p);
9553 }
9556 {
9559 strict_overflow_p);
9567 strict_overflow_p);
9582 strict_overflow_p);
9586 strict_overflow_p);
9589 {
9601 }
9605 }
9607 }
9609 /* Return true when T is an address and is known to be nonzero.
9610 Handle warnings about undefined signed overflow. */
9612 static bool
9614 {
9621 "determining that expression is always "
9623 WARN_STRICT_OVERFLOW_MISC);
9625 }
9627 /* Fold a binary expression of code CODE and type TYPE with operands
9628 OP0 and OP1. LOC is the location of the resulting expression.
9629 Return the folded expression if folding is successful. Otherwise,
9630 return NULL_TREE. */
9632 tree
9635 {
9650 /* Strip any conversions that don't change the mode. This is
9651 safe for every expression, except for a comparison expression
9652 because its signedness is derived from its operands. So, in
9653 the latter case, only strip conversions that don't change the
9654 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9655 preserved.
9657 Note that this is done as an internal manipulation within the
9658 constant folder, in order to find the simplest representation
9659 of the arguments so that their form can be studied. In any
9660 cases, the appropriate type conversions should be put back in
9661 the tree that will get out of the constant folder. */
9664 {
9667 }
9668 else
9669 {
9672 }
9674 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9675 constant but we can't do arithmetic on them. */
9677 {
9680 {
9684 }
9685 }
9687 /* If this is a commutative operation, and ARG0 is a constant, move it
9688 to ARG1 to reduce the number of tests below. */
9693 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9694 to ARG1 to reduce the number of tests below. */
9703 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9705 First check for cases where an arithmetic operation is applied to a
9706 compound, conditional, or comparison operation. Push the arithmetic
9707 operation inside the compound or conditional to see if any folding
9708 can then be done. Convert comparison to conditional for this purpose.
9709 The also optimizes non-constant cases that used to be done in
9710 expand_expr.
9712 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9713 one of the operands is a comparison and the other is a comparison, a
9714 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9715 code below would make the expression more complex. Change it to a
9716 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9717 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9730 {
9734 boolean_type_node,
9742 }
9746 {
9748 {
9753 tem);
9754 }
9757 {
9762 tem);
9763 }
9768 {
9774 }
9779 {
9785 }
9786 }
9789 {
9791 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9794 {
9800 }
9802 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9805 {
9806 tree base;
9807 HOST_WIDE_INT coffset;
9816 }
9821 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9827 arg1),
9829 arg0)));
9835 {
9836 /* X + (X / CST) * -CST is X % CST. */
9841 {
9850 cst0));
9851 }
9852 }
9854 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9855 one. Make sure the type is not saturating and has the signedness of
9856 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9857 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9864 {
9868 }
9871 {
9872 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9873 with a constant, and the two constants have no bits in common,
9874 we should treat this as a BIT_IOR_EXPR since this may produce more
9875 simplifications. */
9882 {
9885 }
9887 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9888 (plus (plus (mult) (mult)) (foo)) so that we can
9889 take advantage of the factoring cases below. */
9898 {
9904 else
9917 parg0),
9919 marg)),
9923 return
9929 parg1)));
9930 }
9931 }
9932 else
9933 {
9934 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9935 to __complex__ ( x, y ). This is not the same for SNaNs or
9936 if signed zeros are involved. */
9940 {
9947 {
9951 {
9957 }
9959 {
9965 }
9966 }
9967 }
9975 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9976 We associate floats only if the user has specified
9977 -fassociative-math. */
9981 {
9986 {
9987 tree tree0;
9990 }
9991 }
9992 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9993 We associate floats only if the user has specified
9994 -fassociative-math. */
9998 {
10003 {
10004 tree tree0;
10007 }
10008 }
10009 }
10011 bit_rotate:
10012 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
10013 is a rotate of A by C1 bits. */
10014 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
10015 is a rotate of A by B bits. */
10016 {
10018 tree rtype;
10027 /* Only create rotates in complete modes. Other cases are not
10028 expanded properly. */
10031 {
10045 {
10049 code0 == LSHIFT_EXPR
10053 }
10055 {
10063 element_precision
10067 return
10070 ? LROTATE_EXPR
10075 }
10077 {
10085 element_precision
10089 return fold_convert_loc
10092 ? LROTATE_EXPR
10096 }
10097 }
10098 }
10100 associate:
10101 /* In most languages, can't associate operations on floats through
10102 parentheses. Rather than remember where the parentheses were, we
10103 don't associate floats at all, unless the user has specified
10104 -fassociative-math.
10105 And, we need to make sure type is not saturating. */
10109 {
10115 /* Split both trees into variables, constants, and literals. Then
10116 associate each group together, the constants with literals,
10117 then the result with variables. This increases the chances of
10118 literals being recombined later and of generating relocatable
10119 expressions for the sum of a constant and literal. */
10124 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10128 /* With undefined overflow prefer doing association in a type
10129 which wraps on overflow, if that is one of the operand types. */
10132 {
10140 }
10142 /* With undefined overflow we can only associate constants with one
10143 variable, and constants whose association doesn't overflow. */
10146 {
10148 {
10166 /* The only case we can still associate with two variables
10167 is if they are the same, modulo negation and bit-pattern
10168 preserving conversions. */
10171 }
10172 }
10174 /* Only do something if we found more than two objects. Otherwise,
10175 nothing has changed and we risk infinite recursion. */
10181 {
10193 /* Preserve the MINUS_EXPR if the negative part of the literal is
10194 greater than the positive part. Otherwise, the multiplicative
10195 folding code (i.e extract_muldiv) may be fooled in case
10196 unsigned constants are subtracted, like in the following
10197 example: ((X*2 + 4) - 8U)/2. */
10199 {
10203 {
10207 }
10208 else
10209 {
10213 }
10214 }
10216 /* Don't introduce overflows through reassociation. */
10223 {
10225 return
10229 else
10230 {
10233 return
10237 }
10238 }
10241 return
10244 }
10245 }
10250 /* Pointer simplifications for subtraction, simple reassociations. */
10252 {
10253 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10256 {
10266 }
10267 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10269 {
10276 }
10277 /* PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A, assuming PTR0 - PTR1
10278 simplifies. */
10280 {
10287 arg10);
10290 }
10291 }
10292 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10303 {
10304 /* Fold A - (A & B) into ~B & A. */
10307 {
10309 {
10316 }
10318 {
10325 }
10326 }
10328 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10329 any power of 2 minus 1. */
10334 {
10340 {
10344 }
10345 }
10346 }
10348 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10349 __complex__ ( x, -y ). This is not the same for SNaNs or if
10350 signed zeros are involved. */
10354 {
10361 {
10365 {
10367 arg1r ? arg1r
10372 }
10374 {
10378 arg1i ? arg1i
10381 }
10382 }
10383 }
10385 /* A - B -> A + (-B) if B is easily negatable. */
10389 /* Avoid this transformation if B is a positive REAL_CST. */
10398 /* Fold &a[i] - &a[j] to i-j. */
10403 {
10409 }
10412 && flag_unsafe_math_optimizations
10418 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
10419 one. Make sure the type is not saturating and has the signedness of
10420 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10421 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10428 {
10432 }
10437 /* (-A) * (-B) -> A * B */
10452 {
10453 /* Transform x * -C into -x * C if x is easily negatable. */
10462 tem);
10464 /* (a * (1 << b)) is (a << b) */
10474 /* (A + A) * C -> A * 2 * C */
10486 /* ((T) (X /[ex] C)) * C cancels out if the conversion is
10487 sign-changing only. */
10497 {
10500 "occur when simplifying "
10502 WARN_STRICT_OVERFLOW_MISC);
10504 }
10506 /* Optimize z * conj(z) for integer complex numbers. */
10513 }
10514 else
10515 {
10516 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10517 the result for floating point types due to rounding so it is applied
10518 only if -fassociative-math was specify. */
10523 {
10525 arg1);
10529 }
10531 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10533 {
10536 {
10539 }
10540 }
10542 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10543 This is not the same for NaNs or if signed zeros are
10544 involved. */
10550 {
10553 return
10559 return
10564 }
10566 /* Optimize z * conj(z) for floating point complex numbers.
10567 Guarded by flag_unsafe_math_optimizations as non-finite
10568 imaginary components don't produce scalar results. */
10579 {
10583 /* Optimizations of root(...)*root(...). */
10585 {
10590 /* Optimize sqrt(x)*sqrt(x) as x. */
10596 /* Optimize root(x)*root(y) as root(x*y). */
10600 }
10602 /* Optimize expN(x)*expN(y) as expN(x+y). */
10604 {
10610 }
10612 /* Optimizations of pow(...)*pow(...). */
10616 {
10622 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10624 {
10629 }
10631 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10633 {
10638 }
10639 }
10641 /* Optimize tan(x)*cos(x) as sin(x). */
10650 {
10656 }
10658 /* Optimize x*pow(x,c) as pow(x,c+1). */
10662 {
10668 {
10670 REAL_VALUE_TYPE c;
10671 tree arg;
10677 }
10678 }
10680 /* Optimize pow(x,c)*x as pow(x,c+1). */
10684 {
10690 {
10692 REAL_VALUE_TYPE c;
10693 tree arg;
10699 }
10700 }
10702 /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x. */
10704 && optimize
10706 {
10710 {
10713 }
10714 }
10715 }
10716 }
10720 bit_ior:
10721 /* Canonicalize (X & C1) | C2. */
10725 {
10730 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10738 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10743 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10744 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10745 mode which allows further optimizations. */
10750 {
10754 {
10757 }
10758 }
10765 c3)),
10766 arg1);
10767 }
10769 /* (X & ~Y) | (~X & Y) is X ^ Y */
10772 {
10789 }
10795 /* See if this can be simplified into a rotate first. If that
10796 is unsuccessful continue in the association code. */
10800 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10808 /* See if this can be simplified into a rotate first. If that
10809 is unsuccessful continue in the association code. */
10813 /* ~X & X, (X == 0) & X, and !X & X are always zero. */
10821 /* X & ~X , X & (X == 0), and X & !X are always zero. */
10829 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10834 {
10835 tree tem2;
10842 }
10843 /* Fold ~X & 1 as (X & 1) == 0. */
10847 {
10848 tree tem2;
10855 }
10856 /* Fold !X & 1 as X == 0. */
10859 {
10863 }
10865 /* Fold (X ^ Y) & Y as ~X & Y. */
10868 {
10873 }
10874 /* Fold (X ^ Y) & X as ~Y & X. */
10878 {
10883 }
10884 /* Fold X & (X ^ Y) as X & ~Y. */
10887 {
10892 }
10893 /* Fold X & (Y ^ X) as ~Y & X. */
10897 {
10902 }
10904 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10905 multiple of 1 << CST. */
10907 {
10914 }
10916 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10917 bits from CST2. */
10921 {
10929 {
10930 /* Avoid the transform if arg1 is a mask of some
10931 mode which allows further optimizations. */
10938 }
10939 }
10941 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10942 ((A & N) + B) & M -> (A + B) & M
10943 Similarly if (N & M) == 0,
10944 ((A | N) + B) & M -> (A + B) & M
10945 and for - instead of + (or unary - instead of +)
10946 and/or ^ instead of |.
10947 If B is constant and (B & M) == 0, fold into A & M. */
10949 {
10958 {
10961 wide_int cst0;
10963 /* Now we know that arg0 is (C + D) or (C - D) or
10964 -C and arg1 (M) is == (1LL << cst) - 1.
10965 Store C into PMOP[0] and D into PMOP[1]. */
10969 {
10972 }
10979 {
10989 {
10992 }
10995 /* If C or D is of the form (A & N) where
10996 (N & M) == M, or of the form (A | N) or
10997 (A ^ N) where (N & M) == 0, replace it with A. */
11001 /* If C or D is a N where (N & M) == 0, it can be
11002 omitted (assumed 0). */
11010 }
11012 /* Only build anything new if we optimized one or both arguments
11013 above. */
11017 {
11020 {
11021 /* Perform the operations in a type that has defined
11022 overflow behavior. */
11028 }
11033 {
11041 else
11043 }
11046 else
11049 /* TEM is now the new binary +, - or unary - replacement. */
11053 }
11054 }
11055 }
11060 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11063 {
11068 return
11070 }
11072 /* If arg0 is derived from the address of an object or function, we may
11073 be able to fold this expression using the object or function's
11074 alignment. */
11076 {
11082 /* This works because modulus is a power of 2. If this weren't the
11083 case, we'd have to replace it by its greatest power-of-2
11084 divisor: modulus & -modulus. */
11089 }
11094 /* Don't touch a floating-point divide by zero unless the mode
11095 of the constant can represent infinity. */
11101 /* (-A) / (-B) -> A / B */
11111 /* Convert A/B/C to A/(B*C). */
11118 /* Convert A/(B/C) to (A/B)*C. */
11126 /* Convert C1/(X*C2) into (C1/C2)/X. */
11131 {
11137 }
11140 {
11144 /* Optimize sin(x)/cos(x) as tan(x). */
11150 {
11155 }
11157 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11163 {
11167 {
11172 }
11173 }
11175 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11176 NaNs or Infinities. */
11180 {
11187 {
11192 }
11193 }
11195 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11196 NaNs or Infinities. */
11200 {
11207 {
11211 {
11215 tmp);
11216 }
11217 }
11218 }
11220 /* Optimize pow(x,c)/x as pow(x,c-1). */
11224 {
11230 {
11232 REAL_VALUE_TYPE c;
11233 tree arg;
11239 }
11240 }
11242 /* Optimize a/root(b/c) into a*root(c/b). */
11244 {
11248 {
11257 }
11258 }
11260 /* Optimize x/expN(y) into x*expN(-y). */
11262 {
11269 }
11271 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11275 {
11283 }
11284 }
11288 /* Optimize (X & (-A)) / A where A is a power of 2,
11289 to X >> log2(A) */
11293 {
11301 }
11302 }
11304 /* Fall through */
11307 /* Simplify A / (B << N) where A and B are positive and B is
11308 a power of 2, to A >> (N + log2(B)). */
11313 {
11316 {
11324 WARN_STRICT_OVERFLOW_MISC);
11330 }
11331 }
11333 /* Fall through */
11341 /* Convert -A / -B to A / B when the type is signed and overflow is
11342 undefined. */
11346 {
11349 "when distributing negation across "
11351 WARN_STRICT_OVERFLOW_MISC);
11357 }
11361 {
11364 "when distributing negation across "
11366 WARN_STRICT_OVERFLOW_MISC);
11372 }
11374 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11375 operation, EXACT_DIV_EXPR.
11377 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11378 At one time others generated faster code, it's not clear if they do
11379 after the last round to changes to the DIV code in expmed.c. */
11388 {
11392 WARN_STRICT_OVERFLOW_MISC);
11394 }
11406 {
11410 WARN_STRICT_OVERFLOW_MISC);
11412 }
11420 /* Since negative shift count is not well-defined,
11421 don't try to compute it in the compiler. */
11427 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11432 {
11436 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11437 being well defined. */
11439 {
11445 else
11447 }
11451 }
11453 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11454 into x & ((unsigned)-1 >> c) for unsigned types. */
11462 {
11465 tree lshift;
11466 tree arg00;
11469 {
11476 }
11477 }
11479 /* If we have a rotate of a bit operation with the rotate count and
11480 the second operand of the bit operation both constant,
11481 permute the two operations. */
11493 /* Two consecutive rotates adding up to the some integer
11494 multiple of the precision of the type can be ignored. */
11502 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11503 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11504 if the latter can be further optimized. */
11509 {
11513 arg1);
11517 arg1);
11521 }
11538 /* Note that the operands of this must be ints
11539 and their values must be 0 or 1.
11540 ("true" is a fixed value perhaps depending on the language.) */
11541 /* If first arg is constant zero, return it. */
11545 /* If either arg is constant true, drop it. */
11549 /* Preserve sequence points. */
11552 /* If second arg is constant zero, result is zero, but first arg
11553 must be evaluated. */
11556 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11557 case will be handled here. */
11561 /* !X && X is always false. */
11565 /* X && !X is always false. */
11570 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11571 means A >= Y && A != MAX, but in this case we know that
11572 A < X <= MAX. */
11576 {
11584 }
11593 /* Note that the operands of this must be ints
11594 and their values must be 0 or true.
11595 ("true" is a fixed value perhaps depending on the language.) */
11596 /* If first arg is constant true, return it. */
11600 /* If either arg is constant zero, drop it. */
11604 /* Preserve sequence points. */
11607 /* If second arg is constant true, result is true, but we must
11608 evaluate first arg. */
11611 /* Likewise for first arg, but note this only occurs here for
11612 TRUTH_OR_EXPR. */
11616 /* !X || X is always true. */
11620 /* X || !X is always true. */
11625 /* (X && !Y) || (!X && Y) is X ^ Y */
11628 {
11645 }
11654 /* If the second arg is constant zero, drop it. */
11657 /* If the second arg is constant true, this is a logical inversion. */
11659 {
11662 }
11663 /* Identical arguments cancel to zero. */
11667 /* !X ^ X is always true. */
11672 /* X ^ !X is always true. */
11688 /* bool_var != 0 becomes bool_var. */
11693 /* bool_var == 1 becomes bool_var. */
11698 /* bool_var != 1 becomes !bool_var. */
11705 /* bool_var == 0 becomes !bool_var. */
11712 /* !exp != 0 becomes !exp */
11717 /* If this is an equality comparison of the address of two non-weak,
11718 unaliased symbols neither of which are extern (since we do not
11719 have access to attributes for externs), then we know the result. */
11724 {
11732 else
11737 type);
11738 }
11740 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11748 arg1),
11751 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
11760 {
11764 val,
11768 }
11770 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
11777 {
11779 code == NE_EXPR
11782 }
11784 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11789 /* If this is an EQ or NE comparison with zero and ARG0 is
11790 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11791 two operations, but the latter can be done in one less insn
11792 on machines that have only two-operand insns or on which a
11793 constant cannot be the first operand. */
11796 {
11801 {
11808 arg1);
11809 }
11812 {
11819 arg1);
11820 }
11821 }
11823 /* If this is an NE or EQ comparison of zero against the result of a
11824 signed MOD operation whose second operand is a power of 2, make
11825 the MOD operation unsigned since it is simpler and equivalent. */
11833 {
11843 }
11845 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11846 C1 is a valid shift constant, and C2 is a power of two, i.e.
11847 a single bit. */
11851 == INTEGER_CST
11854 {
11859 /* Check for a valid shift count. */
11861 {
11865 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11866 can be rewritten as (X & (C2 << C1)) != 0. */
11868 {
11873 }
11874 /* Otherwise, for signed (arithmetic) shifts,
11875 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11876 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11880 /* Otherwise, of unsigned (logical) shifts,
11881 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11882 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11883 else
11887 arg000);
11888 }
11889 }
11891 /* If we have (A & C) == C where C is a power of 2, convert this into
11892 (A & C) != 0. Similarly for NE_EXPR. */
11898 integer_zero_node));
11900 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
11901 bit, then fold the expression into A < 0 or A >= 0. */
11906 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
11907 Similarly for NE_EXPR. */
11911 {
11915 tree dandnotc
11918 notc);
11922 }
11924 /* If this is a comparison of a field, we may be able to simplify it. */
11927 /* Handle the constant case even without -O
11928 to make sure the warnings are given. */
11930 {
11934 }
11936 /* Optimize comparisons of strlen vs zero to a compare of the
11937 first character of the string vs zero. To wit,
11938 strlen(ptr) == 0 => *ptr == 0
11939 strlen(ptr) != 0 => *ptr != 0
11940 Other cases should reduce to one of these two (or a constant)
11941 due to the return value of strlen being unsigned. */
11944 {
11952 {
11957 }
11958 }
11960 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
11961 of X. Similarly fold (X >> C) == 0 into X >= 0. */
11965 {
11970 {
11972 {
11975 }
11978 }
11979 }
11981 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
11982 (X & C) == 0 when C is a single bit. */
11987 {
11994 arg1));
11995 }
11997 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
11998 constant C is a power of two, i.e. a single bit. */
12005 {
12009 }
12011 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12012 when is C is a power of two, i.e. a single bit. */
12019 {
12025 }
12029 {
12032 }
12034 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12037 {
12050 arg01),
12059 arg01),
12068 arg00),
12077 arg00),
12079 }
12083 {
12090 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12091 operand_equal_p guarantees no side-effects so we don't need
12092 to use omit_one_operand on Z. */
12096 arg10));
12100 arg11));
12104 arg10));
12108 arg11));
12110 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12113 {
12119 }
12120 }
12122 /* Attempt to simplify equality/inequality comparisons of complex
12123 values. Only lower the comparison if the result is known or
12124 can be simplified to a single scalar comparison. */
12129 {
12134 {
12137 }
12138 else
12139 {
12142 }
12145 {
12148 }
12149 else
12150 {
12153 }
12157 {
12159 {
12164 }
12165 else
12166 {
12171 }
12172 }
12176 {
12178 {
12183 }
12184 else
12185 {
12190 }
12191 }
12192 }
12204 /* Transform comparisons of the form X +- C CMP X. */
12211 {
12218 else
12221 /* (X - c) > X becomes false. */
12225 {
12229 "occur when assuming that (X - c) > X "
12231 WARN_STRICT_OVERFLOW_ALL);
12233 }
12235 /* Likewise (X + c) < X becomes false. */
12239 {
12243 "occur when assuming that "
12245 WARN_STRICT_OVERFLOW_ALL);
12247 }
12249 /* Convert (X - c) <= X to true. */
12254 {
12258 "occur when assuming that "
12260 WARN_STRICT_OVERFLOW_ALL);
12262 }
12264 /* Convert (X + c) >= X to true. */
12269 {
12273 "occur when assuming that "
12275 WARN_STRICT_OVERFLOW_ALL);
12277 }
12280 {
12281 /* Convert X + c > X and X - c < X to true for integers. */
12285 {
12288 "not occur when assuming that "
12290 WARN_STRICT_OVERFLOW_ALL);
12292 }
12297 {
12300 "not occur when assuming that "
12302 WARN_STRICT_OVERFLOW_ALL);
12304 }
12306 /* Convert X + c <= X and X - c >= X to false for integers. */
12310 {
12313 "not occur when assuming that "
12315 WARN_STRICT_OVERFLOW_ALL);
12317 }
12322 {
12325 "not occur when assuming that "
12327 WARN_STRICT_OVERFLOW_ALL);
12329 }
12330 }
12331 }
12333 /* Comparisons with the highest or lowest possible integer of
12334 the specified precision will have known values. */
12335 {
12341 {
12348 {
12361 /* The GE_EXPR and LT_EXPR cases above are not normally
12362 reached because of previous transformations. */
12366 }
12369 {
12376 arg1);
12382 arg0),
12383 arg1);
12386 }
12389 {
12404 }
12407 {
12414 arg1);
12420 arg0),
12421 arg1);
12424 }
12428 /* We will flip the signedness of the comparison operator
12429 associated with the mode of arg1, so the sign bit is
12430 specified by this mode. Check that arg1 is the signed
12431 max associated with this sign bit. */
12433 /* signed_type does not work on pointer types. */
12435 {
12436 /* The following case also applies to X < signed_max+1
12437 and X >= signed_max+1 because previous transformations. */
12439 {
12445 }
12446 }
12447 }
12448 }
12450 /* If we are comparing an ABS_EXPR with a constant, we can
12451 convert all the cases into explicit comparisons, but they may
12452 well not be faster than doing the ABS and one comparison.
12453 But ABS (X) <= C is a range comparison, which becomes a subtraction
12454 and a comparison, and is probably faster. */
12468 /* Convert ABS_EXPR<x> >= 0 to true. */
12475 {
12478 "when simplifying comparison of "
12480 WARN_STRICT_OVERFLOW_CONDITIONAL);
12483 arg0);
12484 }
12486 /* Convert ABS_EXPR<x> < 0 to false. */
12491 {
12494 "when simplifying comparison of "
12496 WARN_STRICT_OVERFLOW_CONDITIONAL);
12499 arg0);
12500 }
12502 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12503 and similarly for >= into !=. */
12513 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12514 otherwise Y might be >= # of bits in X's type and thus e.g.
12515 (unsigned char) (1 << Y) for Y 15 might be 0.
12516 If the cast is widening, then 1 << Y should have unsigned type,
12517 otherwise if Y is number of bits in the signed shift type minus 1,
12518 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12519 31 might be 0xffffffff80000000. */
12530 {
12536 }
12549 {
12553 }
12555 /* If the first operand is NaN, the result is constant. */
12559 {
12561 ? integer_zero_node
12564 }
12566 /* If the second operand is NaN, the result is constant. */
12570 {
12572 ? integer_zero_node
12575 }
12577 /* Simplify unordered comparison of something with itself. */
12583 && !flag_trapping_math
12587 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12588 {
12600 }
12605 /* When pedantic, a compound expression can be neither an lvalue
12606 nor an integer constant expression. */
12609 /* Don't let (0, 0) be null pointer constant. */
12615 /* An ASSERT_EXPR should never be passed to fold_binary. */
12621 }
12623 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12624 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
12625 of GOTO_EXPR. */
12627 static tree
12629 {
12631 {
12638 /* ... fall through ... */
12642 }
12643 }
12645 /* Return whether the sub-tree ST contains a label which is accessible from
12646 outside the sub-tree. */
12648 static bool
12650 {
12651 return
12653 }
12655 /* Fold a ternary expression of code CODE and type TYPE with operands
12656 OP0, OP1, and OP2. Return the folded expression if folding is
12657 successful. Otherwise, return NULL_TREE. */
12659 tree
12662 {
12663 tree tem;
12670 /* If this is a commutative operation, and OP0 is a constant, move it
12671 to OP1 to reduce the number of tests below. */
12680 /* Strip any conversions that don't change the mode. This is safe
12681 for every expression, except for a comparison expression because
12682 its signedness is derived from its operands. So, in the latter
12683 case, only strip conversions that don't change the signedness.
12685 Note that this is done as an internal manipulation within the
12686 constant folder, in order to find the simplest representation of
12687 the arguments so that their form can be studied. In any cases,
12688 the appropriate type conversions should be put back in the tree
12689 that will get out of the constant folder. */
12691 {
12694 }
12697 {
12700 }
12703 {
12706 }
12709 {
12713 {
12719 }
12724 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12725 so all simple results must be passed through pedantic_non_lvalue. */
12727 {
12730 /* Only optimize constant conditions when the selected branch
12731 has the same type as the COND_EXPR. This avoids optimizing
12732 away "c ? x : throw", where the throw has a void type.
12733 Avoid throwing away that operand which contains label. */
12740 }
12742 {
12747 {
12752 {
12760 }
12764 }
12765 }
12767 /* If we have A op B ? A : C, we may be able to convert this to a
12768 simpler expression, depending on the operation and the values
12769 of B and C. Signed zeros prevent all of these transformations,
12770 for reasons given above each one.
12772 Also try swapping the arguments and inverting the conditional. */
12777 {
12781 }
12785 op2,
12788 {
12792 {
12796 }
12797 }
12799 /* If the second operand is simpler than the third, swap them
12800 since that produces better jump optimization results. */
12803 {
12805 /* See if this can be inverted. If it can't, possibly because
12806 it was a floating-point inequality comparison, don't do
12807 anything. */
12811 }
12813 /* Convert A ? 1 : 0 to simply A. */
12818 /* If we try to convert OP0 to our type, the
12819 call to fold will try to move the conversion inside
12820 a COND, which will recurse. In that case, the COND_EXPR
12821 is probably the best choice, so leave it alone. */
12825 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12826 over COND_EXPR in cases such as floating point comparisons. */
12835 arg0)));
12837 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12842 {
12843 /* sign_bit_p looks through both zero and sign extensions,
12844 but for this optimization only sign extensions are
12845 usable. */
12848 {
12851 {
12854 }
12856 }
12857 /* sign_bit_p only checks ARG1 bits within A's precision.
12858 If <sign bit of A> has wider type than A, bits outside
12859 of A's precision in <sign bit of A> need to be checked.
12860 If they are all 0, this optimization needs to be done
12861 in unsigned A's type, if they are all 1 in signed A's type,
12862 otherwise this can't be done. */
12868 {
12870 tree tem_type;
12883 {
12886 }
12888 {
12891 }
12892 else
12894 }
12897 return
12903 arg1)));
12904 }
12906 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12907 already handled above. */
12912 {
12921 }
12923 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12924 is probably obsolete because the first operand should be a
12925 truth value (that's why we have the two cases above), but let's
12926 leave it in until we can confirm this for all front-ends. */
12938 /* Disable the transformations below for vectors, since
12939 fold_binary_op_with_conditional_arg may undo them immediately,
12940 yielding an infinite loop. */
12944 /* Convert A ? B : 0 into A && B if A and B are truth values. */
12953 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
12958 {
12960 /* Only perform transformation if ARG0 is easily inverted. */
12964 ? BIT_IOR_EXPR
12967 arg1);
12968 }
12970 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
12975 {
12977 /* Only perform transformation if ARG0 is easily inverted. */
12983 op2);
12984 }
12986 /* Convert A ? 1 : B into A || B if A and B are truth values. */
12998 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
12999 of fold_ternary on them. */
13009 {
13019 {
13024 {
13032 }
13034 /* Constructor elements can be subvectors. */
13037 {
13041 }
13043 /* We keep an exact subset of the constructor elements. */
13045 {
13051 {
13055 }
13063 CONSTRUCTOR_ELT
13066 }
13067 /* The bitfield references a single constructor element. */
13069 {
13074 else
13078 }
13079 }
13080 }
13082 /* A bit-field-ref that referenced the full argument can be stripped. */
13088 /* On constants we can use native encode/interpret to constant
13089 fold (nearly) all BIT_FIELD_REFs. */
13093 /* This limitation should not be necessary, we just need to
13094 round this up to mode size. */
13096 /* Need bit-shifting of the buffer to relax the following. */
13098 {
13103 /* ??? We cannot tell native_encode_expr to start at
13104 some random byte only. So limit us to a reasonable amount
13105 of work. */
13107 {
13112 {
13118 }
13119 }
13120 }
13125 /* For integers we can decompose the FMA if possible. */
13137 {
13153 {
13158 /* Make sure that the perm value is in an acceptable
13159 range. */
13168 else
13173 }
13176 {
13181 }
13186 {
13191 }
13197 {
13201 }
13206 /* Some targets are deficient and fail to expand a single
13207 argument permutation while still allowing an equivalent
13208 2-argument version. */
13212 {
13215 }
13218 {
13225 }
13229 }
13235 }
13237 /* Perform constant folding and related simplification of EXPR.
13238 The related simplifications include x*1 => x, x*0 => 0, etc.,
13239 and application of the associative law.
13240 NOP_EXPR conversions may be removed freely (as long as we
13241 are careful not to change the type of the overall expression).
13242 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13243 but we can constant-fold them if they have constant operands. */
13245 #ifdef ENABLE_FOLD_CHECKING
13246 # define fold(x) fold_1 (x)
13248 static
13249 #endif
13250 tree
13252 {
13256 tree tem;
13259 /* Return right away if a constant. */
13263 /* CALL_EXPR-like objects with variable numbers of operands are
13264 treated specially. */
13266 {
13268 {
13271 }
13273 }
13276 {
13281 {
13299 }
13300 }
13303 {
13305 {
13312 {
13317 /* Find a matching index by means of a binary search. */
13319 {
13335 else
13337 }
13338 }
13341 }
13343 /* Return a VECTOR_CST if possible. */
13345 {
13352 tree value;
13355 {
13359 {
13362 }
13363 else
13365 }
13370 }
13378 }
13380 #ifdef ENABLE_FOLD_CHECKING
13381 #undef fold
13388 /* When --enable-checking=fold, compute a digest of expr before
13389 and after actual fold call to see if fold did not accidentally
13390 change original expr. */
13392 tree
13394 {
13395 tree ret;
13415 }
13417 void
13419 {
13430 }
13432 static void
13434 {
13436 }
13438 static void
13441 {
13447 recursive_label:
13457 {
13458 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13463 }
13470 {
13471 /* Allow these fields to be modified. */
13472 tree tmp;
13480 {
13483 }
13484 }
13495 {
13498 {
13513 }
13517 {
13530 }
13547 {
13553 }
13556 {
13558 {
13561 }
13563 }
13574 {
13577 }
13587 }
13588 }
13590 /* Helper function for outputting the checksum of a tree T. When
13591 debugging with gdb, you can "define mynext" to be "next" followed
13592 by "call debug_fold_checksum (op0)", then just trace down till the
13593 outputs differ. */
13595 DEBUG_FUNCTION void
13597 {
13612 }
13614 #endif
13616 /* Fold a unary tree expression with code CODE of type TYPE with an
13617 operand OP0. LOC is the location of the resulting expression.
13618 Return a folded expression if successful. Otherwise, return a tree
13619 expression with code CODE of type TYPE with an operand OP0. */
13621 tree
13624 {
13625 tree tem;
13626 #ifdef ENABLE_FOLD_CHECKING
13635 #endif
13641 #ifdef ENABLE_FOLD_CHECKING
13648 #endif
13650 }
13652 /* Fold a binary tree expression with code CODE of type TYPE with
13653 operands OP0 and OP1. LOC is the location of the resulting
13654 expression. Return a folded expression if successful. Otherwise,
13655 return a tree expression with code CODE of type TYPE with operands
13656 OP0 and OP1. */
13658 tree
13661 MEM_STAT_DECL)
13662 {
13663 tree tem;
13664 #ifdef ENABLE_FOLD_CHECKING
13681 #endif
13687 #ifdef ENABLE_FOLD_CHECKING
13702 #endif
13704 }
13706 /* Fold a ternary tree expression with code CODE of type TYPE with
13707 operands OP0, OP1, and OP2. Return a folded expression if
13708 successful. Otherwise, return a tree expression with code CODE of
13709 type TYPE with operands OP0, OP1, and OP2. */
13711 tree
13714 {
13715 tree tem;
13716 #ifdef ENABLE_FOLD_CHECKING
13740 #endif
13747 #ifdef ENABLE_FOLD_CHECKING
13770 #endif
13772 }
13774 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13775 arguments in ARGARRAY, and a null static chain.
13776 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13777 of type TYPE from the given operands as constructed by build_call_array. */
13779 tree
13782 {
13783 tree tem;
13784 #ifdef ENABLE_FOLD_CHECKING
13803 #endif
13809 #ifdef ENABLE_FOLD_CHECKING
13825 #endif
13827 }
13829 /* Perform constant folding and related simplification of initializer
13830 expression EXPR. These behave identically to "fold_buildN" but ignore
13831 potential run-time traps and exceptions that fold must preserve. */
13833 #define START_FOLD_INIT \
13834 int saved_signaling_nans = flag_signaling_nans;\
13835 int saved_trapping_math = flag_trapping_math;\
13836 int saved_rounding_math = flag_rounding_math;\
13837 int saved_trapv = flag_trapv;\
13838 int saved_folding_initializer = folding_initializer;\
13839 flag_signaling_nans = 0;\
13840 flag_trapping_math = 0;\
13841 flag_rounding_math = 0;\
13842 flag_trapv = 0;\
13843 folding_initializer = 1;
13845 #define END_FOLD_INIT \
13846 flag_signaling_nans = saved_signaling_nans;\
13847 flag_trapping_math = saved_trapping_math;\
13848 flag_rounding_math = saved_rounding_math;\
13849 flag_trapv = saved_trapv;\
13850 folding_initializer = saved_folding_initializer;
13852 tree
13855 {
13856 tree result;
13857 START_FOLD_INIT;
13861 END_FOLD_INIT;
13863 }
13865 tree
13868 {
13869 tree result;
13870 START_FOLD_INIT;
13874 END_FOLD_INIT;
13876 }
13878 tree
13881 {
13882 tree result;
13883 START_FOLD_INIT;
13887 END_FOLD_INIT;
13889 }
13891 #undef START_FOLD_INIT
13892 #undef END_FOLD_INIT
13894 /* Determine if first argument is a multiple of second argument. Return 0 if
13895 it is not, or we cannot easily determined it to be.
13897 An example of the sort of thing we care about (at this point; this routine
13898 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13899 fold cases do now) is discovering that
13901 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13903 is a multiple of
13905 SAVE_EXPR (J * 8)
13907 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13909 This code also handles discovering that
13911 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13913 is a multiple of 8 so we don't have to worry about dealing with a
13914 possible remainder.
13916 Note that we *look* inside a SAVE_EXPR only to determine how it was
13917 calculated; it is not safe for fold to do much of anything else with the
13918 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13919 at run time. For example, the latter example above *cannot* be implemented
13920 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13921 evaluation time of the original SAVE_EXPR is not necessarily the same at
13922 the time the new expression is evaluated. The only optimization of this
13923 sort that would be valid is changing
13925 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13927 divided by 8 to
13929 SAVE_EXPR (I) * SAVE_EXPR (J)
13931 (where the same SAVE_EXPR (J) is used in the original and the
13932 transformed version). */
13934 int
13936 {
13944 {
13946 /* Bitwise and provides a power of two multiple. If the mask is
13947 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13950 /* FALLTHRU */
13963 {
13967 /* const_binop may not detect overflow correctly,
13968 so check for it explicitly here. */
13972 size_one_node,
13973 op1)))
13976 }
13980 /* Can't handle conversions from non-integral or wider integral type. */
13986 /* .. fall through ... */
14003 SIGNED);
14007 }
14008 }
14010 /* Return true if CODE or TYPE is known to be non-negative. */
14012 static bool
14014 {
14017 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14018 have a signed:1 type (where the value is -1 and 0). */
14021 }
14023 /* Return true if (CODE OP0) is known to be non-negative. If the return
14024 value is based on the assumption that signed overflow is undefined,
14025 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14026 *STRICT_OVERFLOW_P. */
14028 bool
14031 {
14036 {
14038 /* We can't return 1 if flag_wrapv is set because
14039 ABS_EXPR<INT_MIN> = INT_MIN. */
14043 {
14046 }
14053 strict_overflow_p);
14055 CASE_CONVERT:
14056 {
14061 {
14064 strict_overflow_p);
14066 {
14070 strict_overflow_p);
14071 }
14072 }
14074 {
14077 strict_overflow_p);
14081 }
14082 }
14087 }
14089 /* We don't know sign of `t', so be conservative and return false. */
14091 }
14093 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14094 value is based on the assumption that signed overflow is undefined,
14095 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14096 *STRICT_OVERFLOW_P. */
14098 bool
14101 {
14106 {
14111 strict_overflow_p)
14113 strict_overflow_p));
14115 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14116 both unsigned and at least 2 bits shorter than the result. */
14120 {
14125 {
14129 }
14130 }
14135 {
14136 /* x * x is always non-negative for floating point x
14137 or without overflow. */
14141 {
14146 }
14147 }
14149 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14150 both unsigned and their total bits is shorter than the result. */
14154 {
14173 {
14183 }
14184 }
14190 strict_overflow_p)
14192 strict_overflow_p));
14203 strict_overflow_p)
14205 strict_overflow_p));
14212 strict_overflow_p);
14215 }
14217 /* We don't know sign of `t', so be conservative and return false. */
14219 }
14221 /* Return true if T is known to be non-negative. If the return
14222 value is based on the assumption that signed overflow is undefined,
14223 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14224 *STRICT_OVERFLOW_P. */
14226 bool
14228 {
14233 {
14245 strict_overflow_p)
14247 strict_overflow_p));
14251 }
14252 /* We don't know sign of `t', so be conservative and return false. */
14254 }
14256 /* Return true if T is known to be non-negative. If the return
14257 value is based on the assumption that signed overflow is undefined,
14258 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14259 *STRICT_OVERFLOW_P. */
14261 bool
14264 {
14267 {
14287 /* Always true. */
14291 /* sqrt(-0.0) is -0.0. */
14295 strict_overflow_p);
14332 /* True if the 1st argument is nonnegative. */
14334 strict_overflow_p);
14337 /* True if the 1st OR 2nd arguments are nonnegative. */
14339 strict_overflow_p)
14341 strict_overflow_p)));
14344 /* True if the 1st AND 2nd arguments are nonnegative. */
14346 strict_overflow_p)
14348 strict_overflow_p)));
14351 /* True if the 2nd argument is nonnegative. */
14353 strict_overflow_p);
14356 /* True if the 1st argument is nonnegative or the second
14357 argument is an even integer. */
14362 strict_overflow_p);
14365 /* True if the 1st argument is nonnegative or the second
14366 argument is an even integer valued real. */
14368 {
14369 REAL_VALUE_TYPE c;
14370 HOST_WIDE_INT n;
14375 {
14376 REAL_VALUE_TYPE cint;
14380 }
14381 }
14383 strict_overflow_p);
14387 }
14389 type);
14390 }
14392 /* Return true if T is known to be non-negative. If the return
14393 value is based on the assumption that signed overflow is undefined,
14394 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14395 *STRICT_OVERFLOW_P. */
14397 static bool
14399 {
14405 {
14407 {
14411 /* If the initializer is non-void, then it's a normal expression
14412 that will be assigned to the slot. */
14416 /* Otherwise, the initializer sets the slot in some way. One common
14417 way is an assignment statement at the end of the initializer. */
14419 {
14427 else
14429 }
14433 strict_overflow_p);
14436 }
14439 {
14445 arg0,
14446 arg1,
14447 strict_overflow_p);
14448 }
14452 strict_overflow_p);
14455 strict_overflow_p);
14458 strict_overflow_p);
14463 }
14465 /* We don't know sign of `t', so be conservative and return false. */
14467 }
14469 /* Return true if T is known to be non-negative. If the return
14470 value is based on the assumption that signed overflow is undefined,
14471 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14472 *STRICT_OVERFLOW_P. */
14474 bool
14476 {
14483 {
14490 strict_overflow_p);
14496 strict_overflow_p);
14505 }
14508 {
14516 strict_overflow_p);
14521 strict_overflow_p);
14534 }
14535 }
14537 /* Return true if `t' is known to be non-negative. Handle warnings
14538 about undefined signed overflow. */
14540 bool
14542 {
14549 "determining that expression is always "
14551 WARN_STRICT_OVERFLOW_MISC);
14553 }
14556 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14557 For floating point we further ensure that T is not denormal.
14558 Similar logic is present in nonzero_address in rtlanal.h.
14560 If the return value is based on the assumption that signed overflow
14561 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14562 change *STRICT_OVERFLOW_P. */
14564 bool
14567 {
14569 {
14572 strict_overflow_p);
14575 {
14581 strict_overflow_p));
14582 }
14587 strict_overflow_p);
14591 }
14594 }
14596 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14597 For floating point we further ensure that T is not denormal.
14598 Similar logic is present in nonzero_address in rtlanal.h.
14600 If the return value is based on the assumption that signed overflow
14601 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14602 change *STRICT_OVERFLOW_P. */
14604 bool
14606 tree type,
14607 tree op0,
14609 {
14612 {
14616 {
14617 /* With the presence of negative values it is hard
14618 to say something. */
14625 /* One of operands must be positive and the other non-negative. */
14626 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14627 overflows, on a twos-complement machine the sum of two
14628 nonnegative numbers can never be zero. */
14630 strict_overflow_p)
14632 strict_overflow_p));
14633 }
14638 {
14640 strict_overflow_p)
14642 strict_overflow_p))
14643 {
14646 }
14647 }
14656 {
14659 }
14666 {
14670 /* When both operands are nonzero, then MAX must be too. */
14672 strict_overflow_p))
14675 /* MAX where operand 0 is positive is positive. */
14677 strict_overflow_p);
14678 }
14679 /* MAX where operand 1 is positive is positive. */
14684 {
14688 }
14693 strict_overflow_p)
14695 strict_overflow_p));
14699 }
14702 }
14704 /* Return true when T is an address and is known to be nonzero.
14705 For floating point we further ensure that T is not denormal.
14706 Similar logic is present in nonzero_address in rtlanal.h.
14708 If the return value is based on the assumption that signed overflow
14709 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14710 change *STRICT_OVERFLOW_P. */
14712 bool
14714 {
14717 {
14722 {
14731 /* For objects in symbol table check if we know they are non-zero.
14732 Don't do anything for variables and functions before symtab is built;
14733 it is quite possible that they will be declared weak later. */
14735 {
14741 else
14743 }
14745 /* Function local objects are never NULL. */
14752 /* Constants are never weak. */
14757 }
14765 {
14769 }
14774 }
14776 }
14778 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14779 attempt to fold the expression to a constant without modifying TYPE,
14780 OP0 or OP1.
14782 If the expression could be simplified to a constant, then return
14783 the constant. If the expression would not be simplified to a
14784 constant, then return NULL_TREE. */
14786 tree
14788 {
14791 }
14793 /* Given the components of a unary expression CODE, TYPE and OP0,
14794 attempt to fold the expression to a constant without modifying
14795 TYPE or OP0.
14797 If the expression could be simplified to a constant, then return
14798 the constant. If the expression would not be simplified to a
14799 constant, then return NULL_TREE. */
14801 tree
14803 {
14806 }
14808 /* If EXP represents referencing an element in a constant string
14809 (either via pointer arithmetic or array indexing), return the
14810 tree representing the value accessed, otherwise return NULL. */
14812 tree
14814 {
14818 {
14820 tree index;
14821 tree string;
14826 else
14827 {
14831 /* Optimize the special-case of a zero lower bound.
14833 We convert the low_bound to sizetype to avoid some problems
14834 with constant folding. (E.g. suppose the lower bound is 1,
14835 and its mode is QI. Without the conversion,l (ARRAY
14836 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14837 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
14843 }
14856 }
14858 }
14860 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14861 an integer constant, real, or fixed-point constant.
14863 TYPE is the type of the result. */
14865 static tree
14867 {
14871 {
14873 {
14880 }
14887 {
14888 FIXED_VALUE_TYPE f;
14893 /* Propagate overflow flags. */
14897 }
14901 }
14904 }
14906 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14907 an integer constant or real constant.
14909 TYPE is the type of the result. */
14911 tree
14913 {
14917 {
14919 {
14920 /* If the value is unsigned or non-negative, then the absolute value
14921 is the same as the ordinary value. */
14925 /* If the value is negative, then the absolute value is
14926 its negation. */
14927 else
14928 {
14933 }
14934 }
14940 else
14946 }
14949 }
14951 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14952 constant. TYPE is the type of the result. */
14954 static tree
14956 {
14960 }
14962 /* Given CODE, a relational operator, the target type, TYPE and two
14963 constant operands OP0 and OP1, return the result of the
14964 relational operation. If the result is not a compile time
14965 constant, then return NULL_TREE. */
14967 static tree
14969 {
14972 /* From here on, the only cases we handle are when the result is
14973 known to be a constant. */
14976 {
14980 /* Handle the cases where either operand is a NaN. */
14982 {
14984 {
15012 }
15015 }
15018 }
15021 {
15025 }
15027 /* Handle equality/inequality of complex constants. */
15029 {
15040 else
15042 }
15045 {
15052 {
15064 }
15067 }
15069 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15071 To compute GT, swap the arguments and do LT.
15072 To compute GE, do LT and invert the result.
15073 To compute LE, swap the arguments, do LT and invert the result.
15074 To compute NE, do EQ and invert the result.
15076 Therefore, the code below must handle only EQ and LT. */
15079 {
15082 }
15084 /* Note that it is safe to invert for real values here because we
15085 have already handled the one case that it matters. */
15089 {
15092 }
15094 /* Compute a result for LT or EQ if args permit;
15095 Otherwise return T. */
15097 {
15100 else
15102 }
15103 else
15109 }
15111 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15112 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15113 itself. */
15115 tree
15117 {
15118 /* If the expression does not have side effects then we don't have to wrap
15119 it with a cleanup point expression. */
15123 /* If the expression is a return, check to see if the expression inside the
15124 return has no side effects or the right hand side of the modify expression
15125 inside the return. If either don't have side effects set we don't need to
15126 wrap the expression in a cleanup point expression. Note we don't check the
15127 left hand side of the modify because it should always be a return decl. */
15129 {
15136 }
15139 }
15141 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15142 of an indirection through OP0, or NULL_TREE if no simplification is
15143 possible. */
15145 tree
15147 {
15149 tree subtype;
15157 {
15160 /* *&CONST_DECL -> to the value of the const decl. */
15163 /* *&p => p; make sure to handle *&"str"[cst] here. */
15165 {
15169 else
15171 }
15172 /* *(foo *)&fooarray => fooarray[0] */
15175 && (!in_gimple_form
15177 {
15187 }
15188 /* *(foo *)&complexfoo => __real__ complexfoo */
15192 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15195 {
15199 }
15200 }
15204 {
15210 {
15211 tree op00type;
15215 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15218 {
15230 }
15231 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15234 {
15238 }
15239 /* ((foo *)&fooarray)[1] => fooarray[1] */
15242 {
15252 }
15253 }
15254 }
15256 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15259 && (!in_gimple_form
15261 {
15262 tree type_domain;
15272 NULL_TREE);
15273 }
15276 }
15278 /* Builds an expression for an indirection through T, simplifying some
15279 cases. */
15281 tree
15283 {
15291 }
15293 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15295 tree
15297 {
15302 else
15304 }
15306 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15307 whose result is ignored. The type of the returned tree need not be
15308 the same as the original expression. */
15310 tree
15312 {
15318 {
15329 else
15335 {
15351 }
15356 }
15357 }
15359 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
15361 tree
15363 {
15369 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15370 have to do anything. Only do this when we are not given a const,
15371 because in that case, this check is more expensive than just
15372 doing it. */
15374 {
15379 }
15381 /* If divisor is a power of two, simplify this to bit manipulation. */
15383 {
15385 {
15399 }
15400 else
15401 {
15402 tree t;
15408 }
15409 }
15410 else
15411 {
15416 }
15419 }
15421 /* Likewise, but round down. */
15423 tree
15425 {
15432 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15433 have to do anything. Only do this when we are not given a const,
15434 because in that case, this check is more expensive than just
15435 doing it. */
15437 {
15442 }
15444 /* If divisor is a power of two, simplify this to bit manipulation. */
15446 {
15447 tree t;
15451 }
15452 else
15453 {
15458 }
15461 }
15463 /* Returns the pointer to the base of the object addressed by EXP and
15464 extracts the information about the offset of the access, storing it
15465 to PBITPOS and POFFSET. */
15467 static tree
15470 {
15471 tree core;
15472 machine_mode mode;
15474 HOST_WIDE_INT bitsize;
15478 {
15483 }
15484 else
15485 {
15489 }
15492 }
15494 /* Returns true if addresses of E1 and E2 differ by a constant, false
15495 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15497 bool
15499 {
15513 {
15523 }
15525 {
15526 /* If only one of the offsets is non-constant, the difference cannot
15527 be a constant. */
15529 }
15530 else
15535 }
15537 /* Simplify the floating point expression EXP when the sign of the
15538 result is not significant. Return NULL_TREE if no simplification
15539 is possible. */
15541 tree
15543 {
15548 {
15584 {
15587 {
15589 /* Strip copysign function call, return the 1st argument. */
15595 /* Strip sign ops from the argument of "odd" math functions. */
15597 {
15601 }
15603 }
15604 }
15609 }
15611 }
15613 /* Return OFF converted to a pointer offset type suitable as offset for
15614 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
15615 tree
15617 {
15619 }
15621 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15622 tree
15624 {
15627 }
15629 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15630 tree
15632 {
15635 }