| blob | 5da6ed3e5d3ee86383225a0f3866b60a0da67370 |
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 /* Transform comparisons of the form X - Y CMP 0 to X CMP Y. */
8788 && equality_code
8790 {
8791 /* ??? The transformation is valid for the other operators if overflow
8792 is undefined for the type, but performing it here badly interacts
8793 with the transformation in fold_cond_expr_with_comparison which
8794 attempts to synthetize ABS_EXPR. */
8798 WARN_STRICT_OVERFLOW_COMPARISON);
8801 }
8803 /* For comparisons of pointers we can decompose it to a compile time
8804 comparison of the base objects and the offsets into the object.
8805 This requires at least one operand being an ADDR_EXPR or a
8806 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8812 {
8815 machine_mode mode;
8819 /* Get base and offset for the access. Strip ADDR_EXPR for
8820 get_inner_reference, but put it back by stripping INDIRECT_REF
8821 off the base object if possible. indirect_baseN will be true
8822 if baseN is not an address but refers to the object itself. */
8825 {
8831 else
8833 }
8835 {
8839 {
8842 }
8845 {
8850 {
8853 }
8854 }
8855 }
8859 {
8865 else
8867 }
8869 {
8873 {
8876 }
8879 {
8884 {
8887 }
8888 }
8889 }
8891 /* A local variable can never be pointed to by
8892 the default SSA name of an incoming parameter. */
8894 && indirect_base0
8897 && !indirect_base1
8902 && indirect_base1
8905 && !indirect_base0
8909 {
8914 }
8915 /* If we have equivalent bases we might be able to simplify. */
8918 {
8919 /* We can fold this expression to a constant if the non-constant
8920 offset parts are equal. */
8929 {
8935 "occur when comparing P +- C1 with "
8937 WARN_STRICT_OVERFLOW_CONDITIONAL);
8940 {
8954 }
8955 }
8956 /* We can simplify the comparison to a comparison of the variable
8957 offset parts if the constant offset parts are equal.
8958 Be careful to use signed sizetype here because otherwise we
8959 mess with array offsets in the wrong way. This is possible
8960 because pointer arithmetic is restricted to retain within an
8961 object and overflow on pointer differences is undefined as of
8962 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8964 && (equality_code
8967 {
8968 /* By converting to signed sizetype we cover middle-end pointer
8969 arithmetic which operates on unsigned pointer types of size
8970 type size and ARRAY_REF offsets which are properly sign or
8971 zero extended from their type in case it is narrower than
8972 sizetype. */
8975 else
8979 else
8986 "occur when comparing P +- C1 with "
8988 WARN_STRICT_OVERFLOW_COMPARISON);
8991 }
8992 }
8993 /* For non-equal bases we can simplify if they are addresses
8994 declarations with different addresses. */
8996 /* We know that !operand_equal_p (base0, base1, 0)
8997 because the if condition was false. But make
8998 sure two decls are not the same. */
9004 /* Watch for aliases. */
9009 {
9016 }
9017 /* For equal offsets we can simplify to a comparison of the
9018 base addresses. */
9020 && (indirect_base0
9022 && (indirect_base1
9027 {
9033 }
9034 }
9036 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
9037 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
9038 the resulting offset is smaller in absolute value than the
9039 original one and has the same sign. */
9048 {
9053 tree cst;
9055 "occur when combining constants around "
9058 /* Put the constant on the side where it doesn't overflow and is
9059 of lower absolute value and of same sign than before. */
9066 {
9069 variable1,
9073 }
9081 {
9087 variable2);
9088 }
9089 }
9091 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
9092 signed arithmetic case. That form is created by the compiler
9093 often enough for folding it to be of value. One example is in
9094 computing loop trip counts after Operator Strength Reduction. */
9101 {
9107 /* Handle unfolded multiplication by zero. */
9112 "eliminating multiplication in comparison "
9114 WARN_STRICT_OVERFLOW_COMPARISON);
9116 /* If const1 is negative we swap the sense of the comparison. */
9121 }
9128 {
9136 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
9143 {
9144 REAL_VALUE_TYPE cst;
9147 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
9148 /* a CMP (-0) -> a CMP 0 */
9153 /* x != NaN is always true, other ops are always false. */
9156 {
9159 }
9161 /* Fold comparisons against infinity. */
9164 {
9168 }
9169 }
9171 /* If this is a comparison of a real constant with a PLUS_EXPR
9172 or a MINUS_EXPR of a real constant, we can convert it into a
9173 comparison with a revised real constant as long as no overflow
9174 occurs when unsafe_math_optimizations are enabled. */
9186 /* Likewise, we can simplify a comparison of a real constant with
9187 a MINUS_EXPR whose first operand is also a real constant, i.e.
9188 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9189 floating-point types only if -fassociative-math is set. */
9195 arg1))
9200 /* Fold comparisons against built-in math functions. */
9202 && flag_unsafe_math_optimizations
9204 {
9208 {
9212 }
9213 }
9214 }
9218 {
9219 /* If we are widening one operand of an integer comparison,
9220 see if the other operand is similarly being widened. Perhaps we
9221 can do the comparison in the narrower type. */
9226 /* Or if we are changing signedness. */
9230 }
9232 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9233 constant, we can simplify it. */
9238 {
9242 }
9244 /* Simplify comparison of something with itself. (For IEEE
9245 floating-point, we can only do some of these simplifications.) */
9247 {
9249 {
9264 /* For NE, we can only do this simplification if integer
9265 or we don't honor IEEE floating point NaNs. */
9269 /* ... fall through ... */
9275 }
9276 }
9278 /* If we are comparing an expression that just has comparisons
9279 of two integer values, arithmetic expressions of those comparisons,
9280 and constants, we can simplify it. There are only three cases
9281 to check: the two values can either be equal, the first can be
9282 greater, or the second can be greater. Fold the expression for
9283 those three values. Since each value must be 0 or 1, we have
9284 eight possibilities, each of which corresponds to the constant 0
9285 or 1 or one of the six possible comparisons.
9287 This handles common cases like (a > b) == 0 but also handles
9288 expressions like ((x > y) - (y > x)) > 0, which supposedly
9289 occur in macroized code. */
9292 {
9297 /* Don't handle degenerate cases here; they should already
9298 have been handled anyway. */
9307 {
9311 /* We can't just pass T to eval_subst in case cval1 or cval2
9312 was the same as ARG1. */
9314 tree high_result
9318 arg1);
9319 tree equal_result
9323 arg1);
9324 tree low_result
9328 arg1);
9330 /* All three of these results should be 0 or 1. Confirm they are.
9331 Then use those values to select the proper code to use. */
9336 {
9337 /* Make a 3-bit mask with the high-order bit being the
9338 value for `>', the next for '=', and the low for '<'. */
9342 {
9344 /* Always false. */
9365 /* Always true. */
9367 }
9370 {
9374 }
9376 }
9377 }
9378 }
9380 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9381 into a single range test. */
9389 {
9393 }
9395 /* Fold ~X op ~Y as Y op X. */
9398 {
9404 }
9406 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9409 {
9415 }
9418 }
9421 /* Subroutine of fold_binary. Optimize complex multiplications of the
9422 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9423 argument EXPR represents the expression "z" of type TYPE. */
9425 static tree
9427 {
9432 {
9435 }
9437 {
9440 }
9441 else
9442 {
9446 }
9455 }
9458 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9459 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9460 guarantees that P and N have the same least significant log2(M) bits.
9461 N is not otherwise constrained. In particular, N is not normalized to
9462 0 <= N < M as is common. In general, the precise value of P is unknown.
9463 M is chosen as large as possible such that constant N can be determined.
9465 Returns M and sets *RESIDUE to N.
9467 If ALLOW_FUNC_ALIGN is true, do take functions' DECL_ALIGN_UNIT into
9468 account. This is not always possible due to PR 35705.
9469 */
9471 static unsigned HOST_WIDE_INT
9474 {
9481 {
9486 }
9488 {
9496 allow_func_align);
9502 {
9505 }
9507 {
9510 {
9513 /* Compute the greatest power-of-2 divisor of op1. */
9517 /* If align is non-zero and less than *modulus, replace
9518 *modulus with align., If align is 0, then either op1 is 0
9519 or the greatest power-of-2 divisor of op1 doesn't fit in an
9520 unsigned HOST_WIDE_INT. In either case, no additional
9521 constraint is imposed. */
9526 }
9527 }
9528 }
9530 /* If we get here, we were unable to determine anything useful about the
9531 expression. */
9533 }
9535 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
9536 CONSTRUCTOR ARG into array ELTS and return true if successful. */
9538 static bool
9540 {
9544 {
9547 }
9549 {
9555 else
9557 }
9558 else
9564 }
9566 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9567 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9568 NULL_TREE otherwise. */
9570 static tree
9572 {
9589 {
9593 }
9596 {
9602 }
9603 else
9605 }
9607 /* Try to fold a pointer difference of type TYPE two address expressions of
9608 array references AREF0 and AREF1 using location LOC. Return a
9609 simplified expression for the difference or NULL_TREE. */
9611 static tree
9614 {
9619 /* If the bases are array references as well, recurse. If the bases
9620 are pointer indirections compute the difference of the pointers.
9621 If the bases are equal, we are set. */
9624 && (base_offset
9632 {
9638 base_offset,
9641 }
9643 }
9645 /* If the real or vector real constant CST of type TYPE has an exact
9646 inverse, return it, else return NULL. */
9648 tree
9650 {
9651 REAL_VALUE_TYPE r;
9653 machine_mode mode;
9657 {
9673 {
9678 }
9684 }
9685 }
9687 /* Mask out the tz least significant bits of X of type TYPE where
9688 tz is the number of trailing zeroes in Y. */
9689 static wide_int
9691 {
9696 }
9698 /* Return true when T is an address and is known to be nonzero.
9699 For floating point we further ensure that T is not denormal.
9700 Similar logic is present in nonzero_address in rtlanal.h.
9702 If the return value is based on the assumption that signed overflow
9703 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9704 change *STRICT_OVERFLOW_P. */
9706 static bool
9708 {
9712 /* Doing something useful for floating point would need more work. */
9718 {
9721 strict_overflow_p);
9727 strict_overflow_p);
9735 }
9738 {
9741 strict_overflow_p);
9749 strict_overflow_p);
9764 strict_overflow_p);
9768 strict_overflow_p);
9771 {
9783 }
9787 }
9789 }
9791 /* Return true when T is an address and is known to be nonzero.
9792 Handle warnings about undefined signed overflow. */
9794 static bool
9796 {
9803 "determining that expression is always "
9805 WARN_STRICT_OVERFLOW_MISC);
9807 }
9809 /* Fold a binary expression of code CODE and type TYPE with operands
9810 OP0 and OP1. LOC is the location of the resulting expression.
9811 Return the folded expression if folding is successful. Otherwise,
9812 return NULL_TREE. */
9814 tree
9817 {
9832 /* Strip any conversions that don't change the mode. This is
9833 safe for every expression, except for a comparison expression
9834 because its signedness is derived from its operands. So, in
9835 the latter case, only strip conversions that don't change the
9836 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9837 preserved.
9839 Note that this is done as an internal manipulation within the
9840 constant folder, in order to find the simplest representation
9841 of the arguments so that their form can be studied. In any
9842 cases, the appropriate type conversions should be put back in
9843 the tree that will get out of the constant folder. */
9846 {
9849 }
9850 else
9851 {
9854 }
9856 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9857 constant but we can't do arithmetic on them. */
9859 {
9862 {
9866 }
9867 }
9869 /* If this is a commutative operation, and ARG0 is a constant, move it
9870 to ARG1 to reduce the number of tests below. */
9875 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9876 to ARG1 to reduce the number of tests below. */
9885 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9887 First check for cases where an arithmetic operation is applied to a
9888 compound, conditional, or comparison operation. Push the arithmetic
9889 operation inside the compound or conditional to see if any folding
9890 can then be done. Convert comparison to conditional for this purpose.
9891 The also optimizes non-constant cases that used to be done in
9892 expand_expr.
9894 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9895 one of the operands is a comparison and the other is a comparison, a
9896 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9897 code below would make the expression more complex. Change it to a
9898 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9899 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9912 {
9916 boolean_type_node,
9924 }
9928 {
9930 {
9935 tem);
9936 }
9939 {
9944 tem);
9945 }
9950 {
9956 }
9961 {
9967 }
9968 }
9971 {
9973 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9976 {
9982 }
9984 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9987 {
9988 tree base;
9989 HOST_WIDE_INT coffset;
9998 }
10003 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
10009 arg1),
10011 arg0)));
10017 {
10018 /* X + (X / CST) * -CST is X % CST. */
10023 {
10032 cst0));
10033 }
10034 }
10036 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
10037 one. Make sure the type is not saturating and has the signedness of
10038 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10039 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10046 {
10050 }
10053 {
10054 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
10055 with a constant, and the two constants have no bits in common,
10056 we should treat this as a BIT_IOR_EXPR since this may produce more
10057 simplifications. */
10064 {
10067 }
10069 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
10070 (plus (plus (mult) (mult)) (foo)) so that we can
10071 take advantage of the factoring cases below. */
10080 {
10086 else
10099 parg0),
10101 marg)),
10105 return
10111 parg1)));
10112 }
10113 }
10114 else
10115 {
10116 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
10117 to __complex__ ( x, y ). This is not the same for SNaNs or
10118 if signed zeros are involved. */
10122 {
10129 {
10133 {
10139 }
10141 {
10147 }
10148 }
10149 }
10157 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
10158 We associate floats only if the user has specified
10159 -fassociative-math. */
10163 {
10168 {
10169 tree tree0;
10172 }
10173 }
10174 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
10175 We associate floats only if the user has specified
10176 -fassociative-math. */
10180 {
10185 {
10186 tree tree0;
10189 }
10190 }
10191 }
10193 bit_rotate:
10194 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
10195 is a rotate of A by C1 bits. */
10196 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
10197 is a rotate of A by B bits. */
10198 {
10200 tree rtype;
10209 /* Only create rotates in complete modes. Other cases are not
10210 expanded properly. */
10213 {
10227 {
10231 code0 == LSHIFT_EXPR
10235 }
10237 {
10245 element_precision
10249 return
10252 ? LROTATE_EXPR
10257 }
10259 {
10267 element_precision
10271 return fold_convert_loc
10274 ? LROTATE_EXPR
10278 }
10279 }
10280 }
10282 associate:
10283 /* In most languages, can't associate operations on floats through
10284 parentheses. Rather than remember where the parentheses were, we
10285 don't associate floats at all, unless the user has specified
10286 -fassociative-math.
10287 And, we need to make sure type is not saturating. */
10291 {
10297 /* Split both trees into variables, constants, and literals. Then
10298 associate each group together, the constants with literals,
10299 then the result with variables. This increases the chances of
10300 literals being recombined later and of generating relocatable
10301 expressions for the sum of a constant and literal. */
10306 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10310 /* With undefined overflow prefer doing association in a type
10311 which wraps on overflow, if that is one of the operand types. */
10314 {
10322 }
10324 /* With undefined overflow we can only associate constants with one
10325 variable, and constants whose association doesn't overflow. */
10328 {
10330 {
10348 /* The only case we can still associate with two variables
10349 is if they are the same, modulo negation and bit-pattern
10350 preserving conversions. */
10353 }
10354 }
10356 /* Only do something if we found more than two objects. Otherwise,
10357 nothing has changed and we risk infinite recursion. */
10363 {
10375 /* Preserve the MINUS_EXPR if the negative part of the literal is
10376 greater than the positive part. Otherwise, the multiplicative
10377 folding code (i.e extract_muldiv) may be fooled in case
10378 unsigned constants are subtracted, like in the following
10379 example: ((X*2 + 4) - 8U)/2. */
10381 {
10385 {
10389 }
10390 else
10391 {
10395 }
10396 }
10398 /* Don't introduce overflows through reassociation. */
10405 {
10407 return
10411 else
10412 {
10415 return
10419 }
10420 }
10423 return
10426 }
10427 }
10432 /* Pointer simplifications for subtraction, simple reassociations. */
10434 {
10435 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10438 {
10448 }
10449 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10451 {
10458 }
10459 /* PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A, assuming PTR0 - PTR1
10460 simplifies. */
10462 {
10469 arg10);
10472 }
10473 }
10474 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10485 {
10486 /* Fold A - (A & B) into ~B & A. */
10489 {
10491 {
10498 }
10500 {
10507 }
10508 }
10510 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10511 any power of 2 minus 1. */
10516 {
10522 {
10526 }
10527 }
10528 }
10530 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10531 __complex__ ( x, -y ). This is not the same for SNaNs or if
10532 signed zeros are involved. */
10536 {
10543 {
10547 {
10549 arg1r ? arg1r
10554 }
10556 {
10560 arg1i ? arg1i
10563 }
10564 }
10565 }
10567 /* A - B -> A + (-B) if B is easily negatable. */
10571 /* Avoid this transformation if B is a positive REAL_CST. */
10580 /* Fold &a[i] - &a[j] to i-j. */
10585 {
10591 }
10594 && flag_unsafe_math_optimizations
10600 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
10601 one. Make sure the type is not saturating and has the signedness of
10602 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10603 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10610 {
10614 }
10619 /* (-A) * (-B) -> A * B */
10634 {
10635 /* Transform x * -C into -x * C if x is easily negatable. */
10644 tem);
10646 /* (a * (1 << b)) is (a << b) */
10656 /* (A + A) * C -> A * 2 * C */
10668 /* ((T) (X /[ex] C)) * C cancels out if the conversion is
10669 sign-changing only. */
10679 {
10682 "occur when simplifying "
10684 WARN_STRICT_OVERFLOW_MISC);
10686 }
10688 /* Optimize z * conj(z) for integer complex numbers. */
10695 }
10696 else
10697 {
10698 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10699 the result for floating point types due to rounding so it is applied
10700 only if -fassociative-math was specify. */
10705 {
10707 arg1);
10711 }
10713 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10715 {
10718 {
10721 }
10722 }
10724 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10725 This is not the same for NaNs or if signed zeros are
10726 involved. */
10732 {
10735 return
10741 return
10746 }
10748 /* Optimize z * conj(z) for floating point complex numbers.
10749 Guarded by flag_unsafe_math_optimizations as non-finite
10750 imaginary components don't produce scalar results. */
10761 {
10765 /* Optimizations of root(...)*root(...). */
10767 {
10772 /* Optimize sqrt(x)*sqrt(x) as x. */
10778 /* Optimize root(x)*root(y) as root(x*y). */
10782 }
10784 /* Optimize expN(x)*expN(y) as expN(x+y). */
10786 {
10792 }
10794 /* Optimizations of pow(...)*pow(...). */
10798 {
10804 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10806 {
10811 }
10813 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10815 {
10820 }
10821 }
10823 /* Optimize tan(x)*cos(x) as sin(x). */
10832 {
10838 }
10840 /* Optimize x*pow(x,c) as pow(x,c+1). */
10844 {
10850 {
10852 REAL_VALUE_TYPE c;
10853 tree arg;
10859 }
10860 }
10862 /* Optimize pow(x,c)*x as pow(x,c+1). */
10866 {
10872 {
10874 REAL_VALUE_TYPE c;
10875 tree arg;
10881 }
10882 }
10884 /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x. */
10886 && optimize
10888 {
10892 {
10895 }
10896 }
10897 }
10898 }
10902 bit_ior:
10903 /* Canonicalize (X & C1) | C2. */
10907 {
10912 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10920 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10925 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10926 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10927 mode which allows further optimizations. */
10932 {
10936 {
10939 }
10940 }
10947 c3)),
10948 arg1);
10949 }
10951 /* (X & ~Y) | (~X & Y) is X ^ Y */
10954 {
10971 }
10977 /* See if this can be simplified into a rotate first. If that
10978 is unsuccessful continue in the association code. */
10982 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10990 /* See if this can be simplified into a rotate first. If that
10991 is unsuccessful continue in the association code. */
10995 /* ~X & X, (X == 0) & X, and !X & X are always zero. */
11003 /* X & ~X , X & (X == 0), and X & !X are always zero. */
11011 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11016 {
11017 tree tem2;
11024 }
11025 /* Fold ~X & 1 as (X & 1) == 0. */
11029 {
11030 tree tem2;
11037 }
11038 /* Fold !X & 1 as X == 0. */
11041 {
11045 }
11047 /* Fold (X ^ Y) & Y as ~X & Y. */
11050 {
11055 }
11056 /* Fold (X ^ Y) & X as ~Y & X. */
11060 {
11065 }
11066 /* Fold X & (X ^ Y) as X & ~Y. */
11069 {
11074 }
11075 /* Fold X & (Y ^ X) as ~Y & X. */
11079 {
11084 }
11086 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11087 multiple of 1 << CST. */
11089 {
11096 }
11098 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11099 bits from CST2. */
11103 {
11111 {
11112 /* Avoid the transform if arg1 is a mask of some
11113 mode which allows further optimizations. */
11120 }
11121 }
11123 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
11124 ((A & N) + B) & M -> (A + B) & M
11125 Similarly if (N & M) == 0,
11126 ((A | N) + B) & M -> (A + B) & M
11127 and for - instead of + (or unary - instead of +)
11128 and/or ^ instead of |.
11129 If B is constant and (B & M) == 0, fold into A & M. */
11131 {
11140 {
11143 wide_int cst0;
11145 /* Now we know that arg0 is (C + D) or (C - D) or
11146 -C and arg1 (M) is == (1LL << cst) - 1.
11147 Store C into PMOP[0] and D into PMOP[1]. */
11151 {
11154 }
11161 {
11171 {
11174 }
11177 /* If C or D is of the form (A & N) where
11178 (N & M) == M, or of the form (A | N) or
11179 (A ^ N) where (N & M) == 0, replace it with A. */
11183 /* If C or D is a N where (N & M) == 0, it can be
11184 omitted (assumed 0). */
11192 }
11194 /* Only build anything new if we optimized one or both arguments
11195 above. */
11199 {
11202 {
11203 /* Perform the operations in a type that has defined
11204 overflow behavior. */
11210 }
11215 {
11223 else
11225 }
11228 else
11231 /* TEM is now the new binary +, - or unary - replacement. */
11235 }
11236 }
11237 }
11242 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11245 {
11250 return
11252 }
11254 /* If arg0 is derived from the address of an object or function, we may
11255 be able to fold this expression using the object or function's
11256 alignment. */
11258 {
11265 /* This works because modulus is a power of 2. If this weren't the
11266 case, we'd have to replace it by its greatest power-of-2
11267 divisor: modulus & -modulus. */
11270 }
11275 /* Don't touch a floating-point divide by zero unless the mode
11276 of the constant can represent infinity. */
11282 /* (-A) / (-B) -> A / B */
11292 /* Convert A/B/C to A/(B*C). */
11299 /* Convert A/(B/C) to (A/B)*C. */
11307 /* Convert C1/(X*C2) into (C1/C2)/X. */
11312 {
11318 }
11321 {
11325 /* Optimize sin(x)/cos(x) as tan(x). */
11331 {
11336 }
11338 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11344 {
11348 {
11353 }
11354 }
11356 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11357 NaNs or Infinities. */
11361 {
11368 {
11373 }
11374 }
11376 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11377 NaNs or Infinities. */
11381 {
11388 {
11392 {
11396 tmp);
11397 }
11398 }
11399 }
11401 /* Optimize pow(x,c)/x as pow(x,c-1). */
11405 {
11411 {
11413 REAL_VALUE_TYPE c;
11414 tree arg;
11420 }
11421 }
11423 /* Optimize a/root(b/c) into a*root(c/b). */
11425 {
11429 {
11438 }
11439 }
11441 /* Optimize x/expN(y) into x*expN(-y). */
11443 {
11450 }
11452 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11456 {
11464 }
11465 }
11469 /* Optimize (X & (-A)) / A where A is a power of 2,
11470 to X >> log2(A) */
11474 {
11482 }
11483 }
11485 /* Fall through */
11488 /* Simplify A / (B << N) where A and B are positive and B is
11489 a power of 2, to A >> (N + log2(B)). */
11494 {
11497 {
11505 WARN_STRICT_OVERFLOW_MISC);
11511 }
11512 }
11514 /* Fall through */
11522 /* Convert -A / -B to A / B when the type is signed and overflow is
11523 undefined. */
11527 {
11530 "when distributing negation across "
11532 WARN_STRICT_OVERFLOW_MISC);
11538 }
11542 {
11545 "when distributing negation across "
11547 WARN_STRICT_OVERFLOW_MISC);
11553 }
11555 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11556 operation, EXACT_DIV_EXPR.
11558 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11559 At one time others generated faster code, it's not clear if they do
11560 after the last round to changes to the DIV code in expmed.c. */
11569 {
11573 WARN_STRICT_OVERFLOW_MISC);
11575 }
11587 {
11591 WARN_STRICT_OVERFLOW_MISC);
11593 }
11601 /* Since negative shift count is not well-defined,
11602 don't try to compute it in the compiler. */
11608 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11613 {
11617 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11618 being well defined. */
11620 {
11626 else
11628 }
11632 }
11634 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11635 into x & ((unsigned)-1 >> c) for unsigned types. */
11643 {
11646 tree lshift;
11647 tree arg00;
11650 {
11657 }
11658 }
11660 /* If we have a rotate of a bit operation with the rotate count and
11661 the second operand of the bit operation both constant,
11662 permute the two operations. */
11674 /* Two consecutive rotates adding up to the some integer
11675 multiple of the precision of the type can be ignored. */
11683 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11684 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11685 if the latter can be further optimized. */
11690 {
11694 arg1);
11698 arg1);
11702 }
11719 /* Note that the operands of this must be ints
11720 and their values must be 0 or 1.
11721 ("true" is a fixed value perhaps depending on the language.) */
11722 /* If first arg is constant zero, return it. */
11726 /* If either arg is constant true, drop it. */
11730 /* Preserve sequence points. */
11733 /* If second arg is constant zero, result is zero, but first arg
11734 must be evaluated. */
11737 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11738 case will be handled here. */
11742 /* !X && X is always false. */
11746 /* X && !X is always false. */
11751 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11752 means A >= Y && A != MAX, but in this case we know that
11753 A < X <= MAX. */
11757 {
11765 }
11774 /* Note that the operands of this must be ints
11775 and their values must be 0 or true.
11776 ("true" is a fixed value perhaps depending on the language.) */
11777 /* If first arg is constant true, return it. */
11781 /* If either arg is constant zero, drop it. */
11785 /* Preserve sequence points. */
11788 /* If second arg is constant true, result is true, but we must
11789 evaluate first arg. */
11792 /* Likewise for first arg, but note this only occurs here for
11793 TRUTH_OR_EXPR. */
11797 /* !X || X is always true. */
11801 /* X || !X is always true. */
11806 /* (X && !Y) || (!X && Y) is X ^ Y */
11809 {
11826 }
11835 /* If the second arg is constant zero, drop it. */
11838 /* If the second arg is constant true, this is a logical inversion. */
11840 {
11843 }
11844 /* Identical arguments cancel to zero. */
11848 /* !X ^ X is always true. */
11853 /* X ^ !X is always true. */
11869 /* bool_var != 0 becomes bool_var. */
11874 /* bool_var == 1 becomes bool_var. */
11879 /* bool_var != 1 becomes !bool_var. */
11886 /* bool_var == 0 becomes !bool_var. */
11893 /* !exp != 0 becomes !exp */
11898 /* If this is an equality comparison of the address of two non-weak,
11899 unaliased symbols neither of which are extern (since we do not
11900 have access to attributes for externs), then we know the result. */
11905 {
11913 else
11918 type);
11919 }
11921 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
11929 arg1),
11932 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
11941 {
11945 val,
11949 }
11951 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
11958 {
11960 code == NE_EXPR
11963 }
11965 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
11970 /* If this is an EQ or NE comparison with zero and ARG0 is
11971 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11972 two operations, but the latter can be done in one less insn
11973 on machines that have only two-operand insns or on which a
11974 constant cannot be the first operand. */
11977 {
11982 {
11989 arg1);
11990 }
11993 {
12000 arg1);
12001 }
12002 }
12004 /* If this is an NE or EQ comparison of zero against the result of a
12005 signed MOD operation whose second operand is a power of 2, make
12006 the MOD operation unsigned since it is simpler and equivalent. */
12014 {
12024 }
12026 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12027 C1 is a valid shift constant, and C2 is a power of two, i.e.
12028 a single bit. */
12032 == INTEGER_CST
12035 {
12040 /* Check for a valid shift count. */
12042 {
12046 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12047 can be rewritten as (X & (C2 << C1)) != 0. */
12049 {
12054 }
12055 /* Otherwise, for signed (arithmetic) shifts,
12056 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12057 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12061 /* Otherwise, of unsigned (logical) shifts,
12062 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12063 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12064 else
12068 arg000);
12069 }
12070 }
12072 /* If we have (A & C) == C where C is a power of 2, convert this into
12073 (A & C) != 0. Similarly for NE_EXPR. */
12079 integer_zero_node));
12081 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12082 bit, then fold the expression into A < 0 or A >= 0. */
12087 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12088 Similarly for NE_EXPR. */
12092 {
12096 tree dandnotc
12099 notc);
12103 }
12105 /* If this is a comparison of a field, we may be able to simplify it. */
12108 /* Handle the constant case even without -O
12109 to make sure the warnings are given. */
12111 {
12115 }
12117 /* Optimize comparisons of strlen vs zero to a compare of the
12118 first character of the string vs zero. To wit,
12119 strlen(ptr) == 0 => *ptr == 0
12120 strlen(ptr) != 0 => *ptr != 0
12121 Other cases should reduce to one of these two (or a constant)
12122 due to the return value of strlen being unsigned. */
12125 {
12133 {
12138 }
12139 }
12141 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12142 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12146 {
12151 {
12153 {
12156 }
12159 }
12160 }
12162 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12163 (X & C) == 0 when C is a single bit. */
12168 {
12175 arg1));
12176 }
12178 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12179 constant C is a power of two, i.e. a single bit. */
12186 {
12190 }
12192 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12193 when is C is a power of two, i.e. a single bit. */
12200 {
12206 }
12210 {
12213 }
12215 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12218 {
12231 arg01),
12240 arg01),
12249 arg00),
12258 arg00),
12260 }
12264 {
12271 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12272 operand_equal_p guarantees no side-effects so we don't need
12273 to use omit_one_operand on Z. */
12277 arg10));
12281 arg11));
12285 arg10));
12289 arg11));
12291 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12294 {
12300 }
12301 }
12303 /* Attempt to simplify equality/inequality comparisons of complex
12304 values. Only lower the comparison if the result is known or
12305 can be simplified to a single scalar comparison. */
12310 {
12315 {
12318 }
12319 else
12320 {
12323 }
12326 {
12329 }
12330 else
12331 {
12334 }
12338 {
12340 {
12345 }
12346 else
12347 {
12352 }
12353 }
12357 {
12359 {
12364 }
12365 else
12366 {
12371 }
12372 }
12373 }
12385 /* Transform comparisons of the form X +- C CMP X. */
12392 {
12399 else
12402 /* (X - c) > X becomes false. */
12406 {
12410 "occur when assuming that (X - c) > X "
12412 WARN_STRICT_OVERFLOW_ALL);
12414 }
12416 /* Likewise (X + c) < X becomes false. */
12420 {
12424 "occur when assuming that "
12426 WARN_STRICT_OVERFLOW_ALL);
12428 }
12430 /* Convert (X - c) <= X to true. */
12435 {
12439 "occur when assuming that "
12441 WARN_STRICT_OVERFLOW_ALL);
12443 }
12445 /* Convert (X + c) >= X to true. */
12450 {
12454 "occur when assuming that "
12456 WARN_STRICT_OVERFLOW_ALL);
12458 }
12461 {
12462 /* Convert X + c > X and X - c < X to true for integers. */
12466 {
12469 "not occur when assuming that "
12471 WARN_STRICT_OVERFLOW_ALL);
12473 }
12478 {
12481 "not occur when assuming that "
12483 WARN_STRICT_OVERFLOW_ALL);
12485 }
12487 /* Convert X + c <= X and X - c >= X to false for integers. */
12491 {
12494 "not occur when assuming that "
12496 WARN_STRICT_OVERFLOW_ALL);
12498 }
12503 {
12506 "not occur when assuming that "
12508 WARN_STRICT_OVERFLOW_ALL);
12510 }
12511 }
12512 }
12514 /* Comparisons with the highest or lowest possible integer of
12515 the specified precision will have known values. */
12516 {
12522 {
12529 {
12542 /* The GE_EXPR and LT_EXPR cases above are not normally
12543 reached because of previous transformations. */
12547 }
12550 {
12557 arg1);
12563 arg0),
12564 arg1);
12567 }
12570 {
12585 }
12588 {
12595 arg1);
12601 arg0),
12602 arg1);
12605 }
12609 /* We will flip the signedness of the comparison operator
12610 associated with the mode of arg1, so the sign bit is
12611 specified by this mode. Check that arg1 is the signed
12612 max associated with this sign bit. */
12614 /* signed_type does not work on pointer types. */
12616 {
12617 /* The following case also applies to X < signed_max+1
12618 and X >= signed_max+1 because previous transformations. */
12620 {
12626 }
12627 }
12628 }
12629 }
12631 /* If we are comparing an ABS_EXPR with a constant, we can
12632 convert all the cases into explicit comparisons, but they may
12633 well not be faster than doing the ABS and one comparison.
12634 But ABS (X) <= C is a range comparison, which becomes a subtraction
12635 and a comparison, and is probably faster. */
12649 /* Convert ABS_EXPR<x> >= 0 to true. */
12656 {
12659 "when simplifying comparison of "
12661 WARN_STRICT_OVERFLOW_CONDITIONAL);
12664 arg0);
12665 }
12667 /* Convert ABS_EXPR<x> < 0 to false. */
12672 {
12675 "when simplifying comparison of "
12677 WARN_STRICT_OVERFLOW_CONDITIONAL);
12680 arg0);
12681 }
12683 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12684 and similarly for >= into !=. */
12694 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12695 otherwise Y might be >= # of bits in X's type and thus e.g.
12696 (unsigned char) (1 << Y) for Y 15 might be 0.
12697 If the cast is widening, then 1 << Y should have unsigned type,
12698 otherwise if Y is number of bits in the signed shift type minus 1,
12699 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12700 31 might be 0xffffffff80000000. */
12711 {
12717 }
12730 {
12734 }
12736 /* If the first operand is NaN, the result is constant. */
12740 {
12742 ? integer_zero_node
12745 }
12747 /* If the second operand is NaN, the result is constant. */
12751 {
12753 ? integer_zero_node
12756 }
12758 /* Simplify unordered comparison of something with itself. */
12764 && !flag_trapping_math
12768 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12769 {
12781 }
12786 /* When pedantic, a compound expression can be neither an lvalue
12787 nor an integer constant expression. */
12790 /* Don't let (0, 0) be null pointer constant. */
12796 /* An ASSERT_EXPR should never be passed to fold_binary. */
12802 }
12804 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12805 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
12806 of GOTO_EXPR. */
12808 static tree
12810 {
12812 {
12819 /* ... fall through ... */
12823 }
12824 }
12826 /* Return whether the sub-tree ST contains a label which is accessible from
12827 outside the sub-tree. */
12829 static bool
12831 {
12832 return
12834 }
12836 /* Fold a ternary expression of code CODE and type TYPE with operands
12837 OP0, OP1, and OP2. Return the folded expression if folding is
12838 successful. Otherwise, return NULL_TREE. */
12840 tree
12843 {
12844 tree tem;
12851 /* If this is a commutative operation, and OP0 is a constant, move it
12852 to OP1 to reduce the number of tests below. */
12861 /* Strip any conversions that don't change the mode. This is safe
12862 for every expression, except for a comparison expression because
12863 its signedness is derived from its operands. So, in the latter
12864 case, only strip conversions that don't change the signedness.
12866 Note that this is done as an internal manipulation within the
12867 constant folder, in order to find the simplest representation of
12868 the arguments so that their form can be studied. In any cases,
12869 the appropriate type conversions should be put back in the tree
12870 that will get out of the constant folder. */
12872 {
12875 }
12878 {
12881 }
12884 {
12887 }
12890 {
12894 {
12900 }
12905 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12906 so all simple results must be passed through pedantic_non_lvalue. */
12908 {
12911 /* Only optimize constant conditions when the selected branch
12912 has the same type as the COND_EXPR. This avoids optimizing
12913 away "c ? x : throw", where the throw has a void type.
12914 Avoid throwing away that operand which contains label. */
12921 }
12923 {
12928 {
12933 {
12941 }
12945 }
12946 }
12948 /* If we have A op B ? A : C, we may be able to convert this to a
12949 simpler expression, depending on the operation and the values
12950 of B and C. Signed zeros prevent all of these transformations,
12951 for reasons given above each one.
12953 Also try swapping the arguments and inverting the conditional. */
12958 {
12962 }
12966 op2,
12969 {
12973 {
12977 }
12978 }
12980 /* If the second operand is simpler than the third, swap them
12981 since that produces better jump optimization results. */
12984 {
12986 /* See if this can be inverted. If it can't, possibly because
12987 it was a floating-point inequality comparison, don't do
12988 anything. */
12992 }
12994 /* Convert A ? 1 : 0 to simply A. */
12999 /* If we try to convert OP0 to our type, the
13000 call to fold will try to move the conversion inside
13001 a COND, which will recurse. In that case, the COND_EXPR
13002 is probably the best choice, so leave it alone. */
13006 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13007 over COND_EXPR in cases such as floating point comparisons. */
13016 arg0)));
13018 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13023 {
13024 /* sign_bit_p looks through both zero and sign extensions,
13025 but for this optimization only sign extensions are
13026 usable. */
13029 {
13032 {
13035 }
13037 }
13038 /* sign_bit_p only checks ARG1 bits within A's precision.
13039 If <sign bit of A> has wider type than A, bits outside
13040 of A's precision in <sign bit of A> need to be checked.
13041 If they are all 0, this optimization needs to be done
13042 in unsigned A's type, if they are all 1 in signed A's type,
13043 otherwise this can't be done. */
13049 {
13051 tree tem_type;
13064 {
13067 }
13069 {
13072 }
13073 else
13075 }
13078 return
13084 arg1)));
13085 }
13087 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13088 already handled above. */
13093 {
13102 }
13104 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13105 is probably obsolete because the first operand should be a
13106 truth value (that's why we have the two cases above), but let's
13107 leave it in until we can confirm this for all front-ends. */
13119 /* Disable the transformations below for vectors, since
13120 fold_binary_op_with_conditional_arg may undo them immediately,
13121 yielding an infinite loop. */
13125 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13134 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13139 {
13141 /* Only perform transformation if ARG0 is easily inverted. */
13145 ? BIT_IOR_EXPR
13148 arg1);
13149 }
13151 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13156 {
13158 /* Only perform transformation if ARG0 is easily inverted. */
13164 op2);
13165 }
13167 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13179 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13180 of fold_ternary on them. */
13190 {
13200 {
13205 {
13213 }
13215 /* Constructor elements can be subvectors. */
13218 {
13222 }
13224 /* We keep an exact subset of the constructor elements. */
13226 {
13232 {
13236 }
13244 CONSTRUCTOR_ELT
13247 }
13248 /* The bitfield references a single constructor element. */
13250 {
13255 else
13259 }
13260 }
13261 }
13263 /* A bit-field-ref that referenced the full argument can be stripped. */
13269 /* On constants we can use native encode/interpret to constant
13270 fold (nearly) all BIT_FIELD_REFs. */
13274 /* This limitation should not be necessary, we just need to
13275 round this up to mode size. */
13277 /* Need bit-shifting of the buffer to relax the following. */
13279 {
13284 /* ??? We cannot tell native_encode_expr to start at
13285 some random byte only. So limit us to a reasonable amount
13286 of work. */
13288 {
13293 {
13299 }
13300 }
13301 }
13306 /* For integers we can decompose the FMA if possible. */
13318 {
13334 {
13339 /* Make sure that the perm value is in an acceptable
13340 range. */
13349 else
13354 }
13357 {
13362 }
13367 {
13372 }
13378 {
13382 }
13387 /* Some targets are deficient and fail to expand a single
13388 argument permutation while still allowing an equivalent
13389 2-argument version. */
13393 {
13396 }
13399 {
13406 }
13410 }
13416 }
13418 /* Perform constant folding and related simplification of EXPR.
13419 The related simplifications include x*1 => x, x*0 => 0, etc.,
13420 and application of the associative law.
13421 NOP_EXPR conversions may be removed freely (as long as we
13422 are careful not to change the type of the overall expression).
13423 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13424 but we can constant-fold them if they have constant operands. */
13426 #ifdef ENABLE_FOLD_CHECKING
13427 # define fold(x) fold_1 (x)
13429 static
13430 #endif
13431 tree
13433 {
13437 tree tem;
13440 /* Return right away if a constant. */
13444 /* CALL_EXPR-like objects with variable numbers of operands are
13445 treated specially. */
13447 {
13449 {
13452 }
13454 }
13457 {
13462 {
13480 }
13481 }
13484 {
13486 {
13493 {
13498 /* Find a matching index by means of a binary search. */
13500 {
13516 else
13518 }
13519 }
13522 }
13524 /* Return a VECTOR_CST if possible. */
13526 {
13533 tree value;
13536 {
13540 {
13543 }
13544 else
13546 }
13551 }
13559 }
13561 #ifdef ENABLE_FOLD_CHECKING
13562 #undef fold
13569 /* When --enable-checking=fold, compute a digest of expr before
13570 and after actual fold call to see if fold did not accidentally
13571 change original expr. */
13573 tree
13575 {
13576 tree ret;
13596 }
13598 void
13600 {
13611 }
13613 static void
13615 {
13617 }
13619 static void
13622 {
13628 recursive_label:
13638 {
13639 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13644 }
13651 {
13652 /* Allow these fields to be modified. */
13653 tree tmp;
13661 {
13664 }
13665 }
13676 {
13679 {
13694 }
13698 {
13711 }
13728 {
13734 }
13737 {
13739 {
13742 }
13744 }
13755 {
13758 }
13768 }
13769 }
13771 /* Helper function for outputting the checksum of a tree T. When
13772 debugging with gdb, you can "define mynext" to be "next" followed
13773 by "call debug_fold_checksum (op0)", then just trace down till the
13774 outputs differ. */
13776 DEBUG_FUNCTION void
13778 {
13793 }
13795 #endif
13797 /* Fold a unary tree expression with code CODE of type TYPE with an
13798 operand OP0. LOC is the location of the resulting expression.
13799 Return a folded expression if successful. Otherwise, return a tree
13800 expression with code CODE of type TYPE with an operand OP0. */
13802 tree
13805 {
13806 tree tem;
13807 #ifdef ENABLE_FOLD_CHECKING
13816 #endif
13822 #ifdef ENABLE_FOLD_CHECKING
13829 #endif
13831 }
13833 /* Fold a binary tree expression with code CODE of type TYPE with
13834 operands OP0 and OP1. LOC is the location of the resulting
13835 expression. Return a folded expression if successful. Otherwise,
13836 return a tree expression with code CODE of type TYPE with operands
13837 OP0 and OP1. */
13839 tree
13842 MEM_STAT_DECL)
13843 {
13844 tree tem;
13845 #ifdef ENABLE_FOLD_CHECKING
13862 #endif
13868 #ifdef ENABLE_FOLD_CHECKING
13883 #endif
13885 }
13887 /* Fold a ternary tree expression with code CODE of type TYPE with
13888 operands OP0, OP1, and OP2. Return a folded expression if
13889 successful. Otherwise, return a tree expression with code CODE of
13890 type TYPE with operands OP0, OP1, and OP2. */
13892 tree
13895 {
13896 tree tem;
13897 #ifdef ENABLE_FOLD_CHECKING
13921 #endif
13928 #ifdef ENABLE_FOLD_CHECKING
13951 #endif
13953 }
13955 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13956 arguments in ARGARRAY, and a null static chain.
13957 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13958 of type TYPE from the given operands as constructed by build_call_array. */
13960 tree
13963 {
13964 tree tem;
13965 #ifdef ENABLE_FOLD_CHECKING
13984 #endif
13990 #ifdef ENABLE_FOLD_CHECKING
14006 #endif
14008 }
14010 /* Perform constant folding and related simplification of initializer
14011 expression EXPR. These behave identically to "fold_buildN" but ignore
14012 potential run-time traps and exceptions that fold must preserve. */
14014 #define START_FOLD_INIT \
14015 int saved_signaling_nans = flag_signaling_nans;\
14016 int saved_trapping_math = flag_trapping_math;\
14017 int saved_rounding_math = flag_rounding_math;\
14018 int saved_trapv = flag_trapv;\
14019 int saved_folding_initializer = folding_initializer;\
14020 flag_signaling_nans = 0;\
14021 flag_trapping_math = 0;\
14022 flag_rounding_math = 0;\
14023 flag_trapv = 0;\
14024 folding_initializer = 1;
14026 #define END_FOLD_INIT \
14027 flag_signaling_nans = saved_signaling_nans;\
14028 flag_trapping_math = saved_trapping_math;\
14029 flag_rounding_math = saved_rounding_math;\
14030 flag_trapv = saved_trapv;\
14031 folding_initializer = saved_folding_initializer;
14033 tree
14036 {
14037 tree result;
14038 START_FOLD_INIT;
14042 END_FOLD_INIT;
14044 }
14046 tree
14049 {
14050 tree result;
14051 START_FOLD_INIT;
14055 END_FOLD_INIT;
14057 }
14059 tree
14062 {
14063 tree result;
14064 START_FOLD_INIT;
14068 END_FOLD_INIT;
14070 }
14072 #undef START_FOLD_INIT
14073 #undef END_FOLD_INIT
14075 /* Determine if first argument is a multiple of second argument. Return 0 if
14076 it is not, or we cannot easily determined it to be.
14078 An example of the sort of thing we care about (at this point; this routine
14079 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14080 fold cases do now) is discovering that
14082 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14084 is a multiple of
14086 SAVE_EXPR (J * 8)
14088 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14090 This code also handles discovering that
14092 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14094 is a multiple of 8 so we don't have to worry about dealing with a
14095 possible remainder.
14097 Note that we *look* inside a SAVE_EXPR only to determine how it was
14098 calculated; it is not safe for fold to do much of anything else with the
14099 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14100 at run time. For example, the latter example above *cannot* be implemented
14101 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14102 evaluation time of the original SAVE_EXPR is not necessarily the same at
14103 the time the new expression is evaluated. The only optimization of this
14104 sort that would be valid is changing
14106 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14108 divided by 8 to
14110 SAVE_EXPR (I) * SAVE_EXPR (J)
14112 (where the same SAVE_EXPR (J) is used in the original and the
14113 transformed version). */
14115 int
14117 {
14125 {
14127 /* Bitwise and provides a power of two multiple. If the mask is
14128 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14131 /* FALLTHRU */
14144 {
14148 /* const_binop may not detect overflow correctly,
14149 so check for it explicitly here. */
14153 size_one_node,
14154 op1)))
14157 }
14161 /* Can't handle conversions from non-integral or wider integral type. */
14167 /* .. fall through ... */
14184 SIGNED);
14188 }
14189 }
14191 /* Return true if CODE or TYPE is known to be non-negative. */
14193 static bool
14195 {
14198 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14199 have a signed:1 type (where the value is -1 and 0). */
14202 }
14204 /* Return true if (CODE OP0) is known to be non-negative. If the return
14205 value is based on the assumption that signed overflow is undefined,
14206 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14207 *STRICT_OVERFLOW_P. */
14209 bool
14212 {
14217 {
14219 /* We can't return 1 if flag_wrapv is set because
14220 ABS_EXPR<INT_MIN> = INT_MIN. */
14224 {
14227 }
14234 strict_overflow_p);
14236 CASE_CONVERT:
14237 {
14242 {
14245 strict_overflow_p);
14247 {
14251 strict_overflow_p);
14252 }
14253 }
14255 {
14258 strict_overflow_p);
14262 }
14263 }
14268 }
14270 /* We don't know sign of `t', so be conservative and return false. */
14272 }
14274 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14275 value is based on the assumption that signed overflow is undefined,
14276 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14277 *STRICT_OVERFLOW_P. */
14279 bool
14282 {
14287 {
14292 strict_overflow_p)
14294 strict_overflow_p));
14296 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14297 both unsigned and at least 2 bits shorter than the result. */
14301 {
14306 {
14310 }
14311 }
14316 {
14317 /* x * x is always non-negative for floating point x
14318 or without overflow. */
14322 {
14327 }
14328 }
14330 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14331 both unsigned and their total bits is shorter than the result. */
14335 {
14354 {
14364 }
14365 }
14371 strict_overflow_p)
14373 strict_overflow_p));
14384 strict_overflow_p)
14386 strict_overflow_p));
14393 strict_overflow_p);
14396 }
14398 /* We don't know sign of `t', so be conservative and return false. */
14400 }
14402 /* Return true if T is known to be non-negative. If the return
14403 value is based on the assumption that signed overflow is undefined,
14404 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14405 *STRICT_OVERFLOW_P. */
14407 bool
14409 {
14414 {
14426 strict_overflow_p)
14428 strict_overflow_p));
14432 }
14433 /* We don't know sign of `t', so be conservative and return false. */
14435 }
14437 /* Return true if T is known to be non-negative. If the return
14438 value is based on the assumption that signed overflow is undefined,
14439 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14440 *STRICT_OVERFLOW_P. */
14442 bool
14445 {
14448 {
14468 /* Always true. */
14472 /* sqrt(-0.0) is -0.0. */
14476 strict_overflow_p);
14513 /* True if the 1st argument is nonnegative. */
14515 strict_overflow_p);
14518 /* True if the 1st OR 2nd arguments are nonnegative. */
14520 strict_overflow_p)
14522 strict_overflow_p)));
14525 /* True if the 1st AND 2nd arguments are nonnegative. */
14527 strict_overflow_p)
14529 strict_overflow_p)));
14532 /* True if the 2nd argument is nonnegative. */
14534 strict_overflow_p);
14537 /* True if the 1st argument is nonnegative or the second
14538 argument is an even integer. */
14543 strict_overflow_p);
14546 /* True if the 1st argument is nonnegative or the second
14547 argument is an even integer valued real. */
14549 {
14550 REAL_VALUE_TYPE c;
14551 HOST_WIDE_INT n;
14556 {
14557 REAL_VALUE_TYPE cint;
14561 }
14562 }
14564 strict_overflow_p);
14568 }
14570 type);
14571 }
14573 /* Return true if T is known to be non-negative. If the return
14574 value is based on the assumption that signed overflow is undefined,
14575 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14576 *STRICT_OVERFLOW_P. */
14578 static bool
14580 {
14586 {
14588 {
14592 /* If the initializer is non-void, then it's a normal expression
14593 that will be assigned to the slot. */
14597 /* Otherwise, the initializer sets the slot in some way. One common
14598 way is an assignment statement at the end of the initializer. */
14600 {
14608 else
14610 }
14614 strict_overflow_p);
14617 }
14620 {
14626 arg0,
14627 arg1,
14628 strict_overflow_p);
14629 }
14633 strict_overflow_p);
14636 strict_overflow_p);
14639 strict_overflow_p);
14644 }
14646 /* We don't know sign of `t', so be conservative and return false. */
14648 }
14650 /* Return true if T is known to be non-negative. If the return
14651 value is based on the assumption that signed overflow is undefined,
14652 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14653 *STRICT_OVERFLOW_P. */
14655 bool
14657 {
14664 {
14671 strict_overflow_p);
14677 strict_overflow_p);
14686 }
14689 {
14697 strict_overflow_p);
14702 strict_overflow_p);
14715 }
14716 }
14718 /* Return true if `t' is known to be non-negative. Handle warnings
14719 about undefined signed overflow. */
14721 bool
14723 {
14730 "determining that expression is always "
14732 WARN_STRICT_OVERFLOW_MISC);
14734 }
14737 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14738 For floating point we further ensure that T is not denormal.
14739 Similar logic is present in nonzero_address in rtlanal.h.
14741 If the return value is based on the assumption that signed overflow
14742 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14743 change *STRICT_OVERFLOW_P. */
14745 bool
14748 {
14750 {
14753 strict_overflow_p);
14756 {
14762 strict_overflow_p));
14763 }
14768 strict_overflow_p);
14772 }
14775 }
14777 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14778 For floating point we further ensure that T is not denormal.
14779 Similar logic is present in nonzero_address in rtlanal.h.
14781 If the return value is based on the assumption that signed overflow
14782 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14783 change *STRICT_OVERFLOW_P. */
14785 bool
14787 tree type,
14788 tree op0,
14790 {
14793 {
14797 {
14798 /* With the presence of negative values it is hard
14799 to say something. */
14806 /* One of operands must be positive and the other non-negative. */
14807 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14808 overflows, on a twos-complement machine the sum of two
14809 nonnegative numbers can never be zero. */
14811 strict_overflow_p)
14813 strict_overflow_p));
14814 }
14819 {
14821 strict_overflow_p)
14823 strict_overflow_p))
14824 {
14827 }
14828 }
14837 {
14840 }
14847 {
14851 /* When both operands are nonzero, then MAX must be too. */
14853 strict_overflow_p))
14856 /* MAX where operand 0 is positive is positive. */
14858 strict_overflow_p);
14859 }
14860 /* MAX where operand 1 is positive is positive. */
14865 {
14869 }
14874 strict_overflow_p)
14876 strict_overflow_p));
14880 }
14883 }
14885 /* Return true when T is an address and is known to be nonzero.
14886 For floating point we further ensure that T is not denormal.
14887 Similar logic is present in nonzero_address in rtlanal.h.
14889 If the return value is based on the assumption that signed overflow
14890 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14891 change *STRICT_OVERFLOW_P. */
14893 bool
14895 {
14898 {
14903 {
14912 /* For objects in symbol table check if we know they are non-zero.
14913 Don't do anything for variables and functions before symtab is built;
14914 it is quite possible that they will be declared weak later. */
14916 {
14922 else
14924 }
14926 /* Function local objects are never NULL. */
14933 /* Constants are never weak. */
14938 }
14946 {
14950 }
14955 }
14957 }
14959 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14960 attempt to fold the expression to a constant without modifying TYPE,
14961 OP0 or OP1.
14963 If the expression could be simplified to a constant, then return
14964 the constant. If the expression would not be simplified to a
14965 constant, then return NULL_TREE. */
14967 tree
14969 {
14972 }
14974 /* Given the components of a unary expression CODE, TYPE and OP0,
14975 attempt to fold the expression to a constant without modifying
14976 TYPE or OP0.
14978 If the expression could be simplified to a constant, then return
14979 the constant. If the expression would not be simplified to a
14980 constant, then return NULL_TREE. */
14982 tree
14984 {
14987 }
14989 /* If EXP represents referencing an element in a constant string
14990 (either via pointer arithmetic or array indexing), return the
14991 tree representing the value accessed, otherwise return NULL. */
14993 tree
14995 {
14999 {
15001 tree index;
15002 tree string;
15007 else
15008 {
15012 /* Optimize the special-case of a zero lower bound.
15014 We convert the low_bound to sizetype to avoid some problems
15015 with constant folding. (E.g. suppose the lower bound is 1,
15016 and its mode is QI. Without the conversion,l (ARRAY
15017 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15018 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15024 }
15037 }
15039 }
15041 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15042 an integer constant, real, or fixed-point constant.
15044 TYPE is the type of the result. */
15046 static tree
15048 {
15052 {
15054 {
15061 }
15068 {
15069 FIXED_VALUE_TYPE f;
15074 /* Propagate overflow flags. */
15078 }
15082 }
15085 }
15087 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15088 an integer constant or real constant.
15090 TYPE is the type of the result. */
15092 tree
15094 {
15098 {
15100 {
15101 /* If the value is unsigned or non-negative, then the absolute value
15102 is the same as the ordinary value. */
15106 /* If the value is negative, then the absolute value is
15107 its negation. */
15108 else
15109 {
15114 }
15115 }
15121 else
15127 }
15130 }
15132 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15133 constant. TYPE is the type of the result. */
15135 static tree
15137 {
15141 }
15143 /* Given CODE, a relational operator, the target type, TYPE and two
15144 constant operands OP0 and OP1, return the result of the
15145 relational operation. If the result is not a compile time
15146 constant, then return NULL_TREE. */
15148 static tree
15150 {
15153 /* From here on, the only cases we handle are when the result is
15154 known to be a constant. */
15157 {
15161 /* Handle the cases where either operand is a NaN. */
15163 {
15165 {
15193 }
15196 }
15199 }
15202 {
15206 }
15208 /* Handle equality/inequality of complex constants. */
15210 {
15221 else
15223 }
15226 {
15233 {
15245 }
15248 }
15250 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15252 To compute GT, swap the arguments and do LT.
15253 To compute GE, do LT and invert the result.
15254 To compute LE, swap the arguments, do LT and invert the result.
15255 To compute NE, do EQ and invert the result.
15257 Therefore, the code below must handle only EQ and LT. */
15260 {
15263 }
15265 /* Note that it is safe to invert for real values here because we
15266 have already handled the one case that it matters. */
15270 {
15273 }
15275 /* Compute a result for LT or EQ if args permit;
15276 Otherwise return T. */
15278 {
15281 else
15283 }
15284 else
15290 }
15292 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15293 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15294 itself. */
15296 tree
15298 {
15299 /* If the expression does not have side effects then we don't have to wrap
15300 it with a cleanup point expression. */
15304 /* If the expression is a return, check to see if the expression inside the
15305 return has no side effects or the right hand side of the modify expression
15306 inside the return. If either don't have side effects set we don't need to
15307 wrap the expression in a cleanup point expression. Note we don't check the
15308 left hand side of the modify because it should always be a return decl. */
15310 {
15317 }
15320 }
15322 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15323 of an indirection through OP0, or NULL_TREE if no simplification is
15324 possible. */
15326 tree
15328 {
15330 tree subtype;
15338 {
15341 /* *&CONST_DECL -> to the value of the const decl. */
15344 /* *&p => p; make sure to handle *&"str"[cst] here. */
15346 {
15350 else
15352 }
15353 /* *(foo *)&fooarray => fooarray[0] */
15356 && (!in_gimple_form
15358 {
15368 }
15369 /* *(foo *)&complexfoo => __real__ complexfoo */
15373 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15376 {
15380 }
15381 }
15385 {
15391 {
15392 tree op00type;
15396 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15399 {
15411 }
15412 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15415 {
15419 }
15420 /* ((foo *)&fooarray)[1] => fooarray[1] */
15423 {
15433 }
15434 }
15435 }
15437 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15440 && (!in_gimple_form
15442 {
15443 tree type_domain;
15453 NULL_TREE);
15454 }
15457 }
15459 /* Builds an expression for an indirection through T, simplifying some
15460 cases. */
15462 tree
15464 {
15472 }
15474 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15476 tree
15478 {
15483 else
15485 }
15487 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15488 whose result is ignored. The type of the returned tree need not be
15489 the same as the original expression. */
15491 tree
15493 {
15499 {
15510 else
15516 {
15532 }
15537 }
15538 }
15540 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
15542 tree
15544 {
15550 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15551 have to do anything. Only do this when we are not given a const,
15552 because in that case, this check is more expensive than just
15553 doing it. */
15555 {
15560 }
15562 /* If divisor is a power of two, simplify this to bit manipulation. */
15564 {
15566 {
15580 }
15581 else
15582 {
15583 tree t;
15589 }
15590 }
15591 else
15592 {
15597 }
15600 }
15602 /* Likewise, but round down. */
15604 tree
15606 {
15613 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15614 have to do anything. Only do this when we are not given a const,
15615 because in that case, this check is more expensive than just
15616 doing it. */
15618 {
15623 }
15625 /* If divisor is a power of two, simplify this to bit manipulation. */
15627 {
15628 tree t;
15632 }
15633 else
15634 {
15639 }
15642 }
15644 /* Returns the pointer to the base of the object addressed by EXP and
15645 extracts the information about the offset of the access, storing it
15646 to PBITPOS and POFFSET. */
15648 static tree
15651 {
15652 tree core;
15653 machine_mode mode;
15655 HOST_WIDE_INT bitsize;
15659 {
15664 }
15665 else
15666 {
15670 }
15673 }
15675 /* Returns true if addresses of E1 and E2 differ by a constant, false
15676 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15678 bool
15680 {
15694 {
15704 }
15706 {
15707 /* If only one of the offsets is non-constant, the difference cannot
15708 be a constant. */
15710 }
15711 else
15716 }
15718 /* Simplify the floating point expression EXP when the sign of the
15719 result is not significant. Return NULL_TREE if no simplification
15720 is possible. */
15722 tree
15724 {
15729 {
15765 {
15768 {
15770 /* Strip copysign function call, return the 1st argument. */
15776 /* Strip sign ops from the argument of "odd" math functions. */
15778 {
15782 }
15784 }
15785 }
15790 }
15792 }
15794 /* Return OFF converted to a pointer offset type suitable as offset for
15795 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
15796 tree
15798 {
15800 }
15802 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15803 tree
15805 {
15808 }
15810 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15811 tree
15813 {
15816 }