| blob | b6e8ed6878330863a6025cd862b23881b76550ec |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /*@@ This file should be rewritten to use an arbitrary precision
23 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
24 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
25 @@ The routines that translate from the ap rep should
26 @@ warn if precision et. al. is lost.
27 @@ This would also make life easier when this technology is used
28 @@ for cross-compilers. */
30 /* The entry points in this file are fold, size_int_wide, size_binop
31 and force_fit_type_double.
33 fold takes a tree as argument and returns a simplified tree.
35 size_binop takes a tree code for an arithmetic operation
36 and two operands that are trees, and produces a tree for the
37 result, assuming the type comes from `sizetype'.
39 size_int takes an integer value, and creates a tree constant
40 with type from `sizetype'.
42 force_fit_type_double takes a constant, an overflowable flag and a
43 prior overflow indicator. It forces the value to fit the type and
44 sets TREE_OVERFLOW.
46 Note: Since the folders get called on non-gimple code as well as
47 gimple code, we need to handle GIMPLE tuples as well as their
48 corresponding tree equivalents. */
69 /* Nonzero if we are folding constants inside an initializer; zero
70 otherwise. */
73 /* The following constants represent a bit based encoding of GCC's
74 comparison operators. This encoding simplifies transformations
75 on relational comparison operators, such as AND and OR. */
93 };
113 HOST_WIDE_INT *,
149 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
150 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
151 and SUM1. Then this yields nonzero if overflow occurred during the
152 addition.
154 Overflow occurs if A and B have the same sign, but A and SUM differ in
155 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
156 sign. */
157 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
158 \f
159 /* If ARG2 divides ARG1 with zero remainder, carries out the division
160 of type CODE and returns the quotient.
161 Otherwise returns NULL_TREE. */
163 tree
165 {
169 /* The sign of the division is according to operand two, that
170 does the correct thing for POINTER_PLUS_EXPR where we want
171 a signed division. */
185 }
186 \f
187 /* This is nonzero if we should defer warnings about undefined
188 overflow. This facility exists because these warnings are a
189 special case. The code to estimate loop iterations does not want
190 to issue any warnings, since it works with expressions which do not
191 occur in user code. Various bits of cleanup code call fold(), but
192 only use the result if it has certain characteristics (e.g., is a
193 constant); that code only wants to issue a warning if the result is
194 used. */
198 /* If a warning about undefined overflow is deferred, this is the
199 warning. Note that this may cause us to turn two warnings into
200 one, but that is fine since it is sufficient to only give one
201 warning per expression. */
205 /* If a warning about undefined overflow is deferred, this is the
206 level at which the warning should be emitted. */
210 /* Start deferring overflow warnings. We could use a stack here to
211 permit nested calls, but at present it is not necessary. */
213 void
215 {
217 }
219 /* Stop deferring overflow warnings. If there is a pending warning,
220 and ISSUE is true, then issue the warning if appropriate. STMT is
221 the statement with which the warning should be associated (used for
222 location information); STMT may be NULL. CODE is the level of the
223 warning--a warn_strict_overflow_code value. This function will use
224 the smaller of CODE and the deferred code when deciding whether to
225 issue the warning. CODE may be zero to mean to always use the
226 deferred code. */
228 void
230 {
232 location_t locus;
237 {
243 }
254 /* Use the smallest code level when deciding to issue the
255 warning. */
264 else
267 }
269 /* Stop deferring overflow warnings, ignoring any deferred
270 warnings. */
272 void
274 {
276 }
278 /* Whether we are deferring overflow warnings. */
280 bool
282 {
284 }
286 /* This is called when we fold something based on the fact that signed
287 overflow is undefined. */
289 static void
291 {
293 {
296 {
299 }
300 }
303 }
304 \f
305 /* Return true if the built-in mathematical function specified by CODE
306 is odd, i.e. -f(x) == f(-x). */
308 static bool
310 {
312 {
346 }
348 }
350 /* Check whether we may negate an integer constant T without causing
351 overflow. */
353 bool
355 {
358 tree type;
368 {
373 }
374 else
379 }
381 /* Determine whether an expression T can be cheaply negated using
382 the function negate_expr without introducing undefined overflow. */
384 static bool
386 {
387 tree type;
396 {
401 /* Check that -CST will not overflow type. */
412 /* We want to canonicalize to positive real constants. Pretend
413 that only negative ones can be easily negated. */
431 /* -(A + B) -> (-B) - A. */
436 /* -(A + B) -> (-A) - B. */
440 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
450 /* Fall through. */
463 /* In general we can't negate A / B, because if A is INT_MIN and
464 B is 1, we may turn this into INT_MIN / -1 which is undefined
465 and actually traps on some architectures. But if overflow is
466 undefined, we can negate, because - (INT_MIN / 1) is an
467 overflow. */
475 /* Negate -((double)float) as (double)(-float). */
477 {
481 }
485 /* Negate -f(x) as f(-x). */
491 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
493 {
499 }
504 }
506 }
508 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
509 simplification is possible.
510 If negate_expr_p would return true for T, NULL_TREE will never be
511 returned. */
513 static tree
515 {
517 tree tem;
520 {
521 /* Convert - (~A) to A + 1. */
537 /* Two's complement FP formats, such as c4x, may overflow. */
547 {
556 }
578 {
579 /* -(A + B) -> (-B) - A. */
583 {
587 }
589 /* -(A + B) -> (-A) - B. */
591 {
595 }
596 }
600 /* - (A - B) -> B - A */
612 /* Fall through. */
616 {
625 }
633 /* In general we can't negate A / B, because if A is INT_MIN and
634 B is 1, we may turn this into INT_MIN / -1 which is undefined
635 and actually traps on some architectures. But if overflow is
636 undefined, we can negate, because - (INT_MIN / 1) is an
637 overflow. */
639 {
644 {
651 }
654 {
661 }
662 }
666 /* Convert -((double)float) into (double)(-float). */
668 {
672 }
676 /* Negate -f(x) as f(-x). */
679 {
685 }
689 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
691 {
696 {
703 }
704 }
709 }
712 }
714 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
715 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
716 return NULL_TREE. */
718 static tree
720 {
722 location_t loc;
733 {
736 }
738 }
739 \f
740 /* Split a tree IN into a constant, literal and variable parts that could be
741 combined with CODE to make IN. "constant" means an expression with
742 TREE_CONSTANT but that isn't an actual constant. CODE must be a
743 commutative arithmetic operation. Store the constant part into *CONP,
744 the literal in *LITP and return the variable part. If a part isn't
745 present, set it to null. If the tree does not decompose in this way,
746 return the entire tree as the variable part and the other parts as null.
748 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
749 case, we negate an operand that was subtracted. Except if it is a
750 literal for which we use *MINUS_LITP instead.
752 If NEGATE_P is true, we are negating all of IN, again except a literal
753 for which we use *MINUS_LITP instead.
755 If IN is itself a literal or constant, return it as appropriate.
757 Note that we do not guarantee that any of the three values will be the
758 same type as IN, but they will have the same signedness and mode. */
760 static tree
763 {
770 /* Strip any conversions that don't change the machine mode or signedness. */
779 /* We can associate addition and subtraction together (even
780 though the C standard doesn't say so) for integers because
781 the value is not affected. For reals, the value might be
782 affected, so we can't. */
785 {
791 /* First see if either of the operands is a literal, then a constant. */
804 /* If we haven't dealt with either operand, this is not a case we can
805 decompose. Otherwise, VAR is either of the ones remaining, if any. */
810 else
813 /* Now do any needed negations. */
820 }
823 else
827 {
834 }
837 }
839 /* Re-associate trees split by the above function. T1 and T2 are
840 either expressions to associate or null. Return the new
841 expression, if any. LOC is the location of the new expression. If
842 we build an operation, do it in TYPE and with CODE. */
844 static tree
846 {
847 tree tem;
854 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
855 try to fold this since we will have infinite recursion. But do
856 deal with any NEGATE_EXPRs. */
859 {
861 {
870 }
872 {
875 }
880 }
884 associate_trees_exit:
887 }
888 \f
889 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
890 for use in int_const_binop, size_binop and size_diffop. */
892 static bool
894 {
901 {
910 }
915 }
918 /* Combine two integer constants ARG1 and ARG2 under operation CODE
919 to produce a new constant. Return NULL_TREE if we don't know how
920 to evaluate CODE at compile-time.
922 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
924 tree
926 {
930 HOST_WIDE_INT hi;
932 HOST_WIDE_INT garbageh;
933 tree t;
936 int is_sizetype
946 {
962 /* It's unclear from the C standard whether shifts can overflow.
963 The following code ignores overflow; perhaps a C standard
964 interpretation ruling is needed. */
993 /* This is a shortcut for a common special case. */
998 {
1004 }
1006 /* ... fall through ... */
1012 {
1015 }
1018 {
1021 }
1028 /* This is a shortcut for a common special case. */
1033 {
1038 }
1040 /* ... fall through ... */
1058 else
1064 else
1070 }
1073 {
1076 /* Propagate overflow flags ourselves. */
1079 {
1082 }
1083 }
1084 else
1090 }
1092 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1093 constant. We assume ARG1 and ARG2 have the same data type, or at least
1094 are the same kind of constant and the same machine mode. Return zero if
1095 combining the constants is not allowed in the current operating mode.
1097 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1099 static tree
1101 {
1102 /* Sanity check for the recursive cases. */
1113 {
1115 REAL_VALUE_TYPE d1;
1116 REAL_VALUE_TYPE d2;
1117 REAL_VALUE_TYPE value;
1118 REAL_VALUE_TYPE result;
1122 /* The following codes are handled by real_arithmetic. */
1124 {
1135 }
1143 /* Don't perform operation if we honor signaling NaNs and
1144 either operand is a NaN. */
1149 /* Don't perform operation if it would raise a division
1150 by zero exception. */
1156 /* If either operand is a NaN, just return it. Otherwise, set up
1157 for floating-point trap; we return an overflow. */
1166 /* Don't constant fold this floating point operation if
1167 the result has overflowed and flag_trapping_math. */
1175 /* Don't constant fold this floating point operation if the
1176 result may dependent upon the run-time rounding mode and
1177 flag_rounding_math is set, or if GCC's software emulation
1178 is unable to accurately represent the result. */
1188 }
1191 {
1192 FIXED_VALUE_TYPE f1;
1193 FIXED_VALUE_TYPE f2;
1194 FIXED_VALUE_TYPE result;
1199 /* The following codes are handled by fixed_arithmetic. */
1201 {
1218 }
1225 /* Propagate overflow flags. */
1229 }
1232 {
1241 {
1252 mpc_mul);
1257 notrunc);
1261 notrunc);
1268 mpc_div);
1269 /* Fallthru ... */
1275 {
1276 /* Keep this algorithm in sync with
1277 tree-complex.c:expand_complex_div_straight().
1279 Expand complex division to scalars, straightforward algorithm.
1280 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1281 t = br*br + bi*bi
1282 */
1283 tree magsquared
1287 notrunc);
1288 tree t1
1292 notrunc);
1293 tree t2
1297 notrunc);
1301 }
1302 else
1303 {
1304 /* Keep this algorithm in sync with
1305 tree-complex.c:expand_complex_div_wide().
1307 Expand complex division to scalars, modified algorithm to minimize
1308 overflow with wide input ranges. */
1314 {
1315 /* In the TRUE branch, we compute
1316 ratio = br/bi;
1317 div = (br * ratio) + bi;
1318 tr = (ar * ratio) + ai;
1319 ti = (ai * ratio) - ar;
1320 tr = tr / div;
1321 ti = ti / div; */
1325 notrunc),
1326 notrunc);
1334 }
1335 else
1336 {
1337 /* In the FALSE branch, we compute
1338 ratio = d/c;
1339 divisor = (d * ratio) + c;
1340 tr = (b * ratio) + a;
1341 ti = b - (a * ratio);
1342 tr = tr / div;
1343 ti = ti / div; */
1347 notrunc),
1348 notrunc);
1357 }
1358 }
1363 }
1367 }
1370 {
1382 {
1385 /* The trailing elements can be empty and should be treated as 0 */
1388 else
1389 {
1392 }
1396 else
1397 {
1400 }
1404 /* It is possible that const_binop cannot handle the given
1405 code and return NULL_TREE */
1410 }
1412 }
1414 }
1416 /* Create a size type INT_CST node with NUMBER sign extended. KIND
1417 indicates which particular sizetype to create. */
1419 tree
1421 {
1423 }
1424 \f
1425 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1426 is a tree code. The type of the result is taken from the operands.
1427 Both must be equivalent integer types, ala int_binop_types_match_p.
1428 If the operands are constant, so is the result. */
1430 tree
1432 {
1441 /* Handle the special case of two integer constants faster. */
1443 {
1444 /* And some specific cases even faster than that. */
1446 {
1451 }
1453 {
1456 }
1458 {
1461 }
1463 /* Handle general case of two integer constants. */
1465 }
1468 }
1470 /* Given two values, either both of sizetype or both of bitsizetype,
1471 compute the difference between the two values. Return the value
1472 in signed type corresponding to the type of the operands. */
1474 tree
1476 {
1478 tree ctype;
1483 /* If the type is already signed, just do the simple thing. */
1491 else
1494 /* If either operand is not a constant, do the conversions to the signed
1495 type and subtract. The hardware will do the right thing with any
1496 overflow in the subtraction. */
1502 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1503 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1504 overflow) and negate (which can't either). Special-case a result
1505 of zero while we're here. */
1511 else
1515 MINUS_EXPR,
1517 }
1518 \f
1519 /* A subroutine of fold_convert_const handling conversions of an
1520 INTEGER_CST to another integer type. */
1522 static tree
1524 {
1525 tree t;
1527 /* Given an integer constant, make new constant with new type,
1528 appropriately sign-extended or truncated. */
1538 }
1540 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1541 to an integer type. */
1543 static tree
1545 {
1547 tree t;
1549 /* The following code implements the floating point to integer
1550 conversion rules required by the Java Language Specification,
1551 that IEEE NaNs are mapped to zero and values that overflow
1552 the target precision saturate, i.e. values greater than
1553 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1554 are mapped to INT_MIN. These semantics are allowed by the
1555 C and C++ standards that simply state that the behavior of
1556 FP-to-integer conversion is unspecified upon overflow. */
1558 double_int val;
1559 REAL_VALUE_TYPE r;
1563 {
1570 }
1572 /* If R is NaN, return zero and show we have an overflow. */
1574 {
1577 }
1579 /* See if R is less than the lower bound or greater than the
1580 upper bound. */
1583 {
1587 {
1590 }
1591 }
1594 {
1597 {
1600 {
1603 }
1604 }
1605 }
1613 }
1615 /* A subroutine of fold_convert_const handling conversions of a
1616 FIXED_CST to an integer type. */
1618 static tree
1620 {
1621 tree t;
1625 /* Right shift FIXED_CST to temp by fbit. */
1629 {
1631 HOST_BITS_PER_DOUBLE_INT,
1634 /* Left shift temp to temp_trunc by fbit. */
1636 HOST_BITS_PER_DOUBLE_INT,
1638 }
1639 else
1640 {
1643 }
1645 /* If FIXED_CST is negative, we need to round the value toward 0.
1646 By checking if the fractional bits are not zero to add 1 to temp. */
1652 /* Given a fixed-point constant, make new constant with new type,
1653 appropriately sign-extended or truncated. */
1661 }
1663 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1664 to another floating point type. */
1666 static tree
1668 {
1669 REAL_VALUE_TYPE value;
1670 tree t;
1675 /* If converting an infinity or NAN to a representation that doesn't
1676 have one, set the overflow bit so that we can produce some kind of
1677 error message at the appropriate point if necessary. It's not the
1678 most user-friendly message, but it's better than nothing. */
1685 /* Regular overflow, conversion produced an infinity in a mode that
1686 can't represent them. */
1691 else
1694 }
1696 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1697 to a floating point type. */
1699 static tree
1701 {
1702 REAL_VALUE_TYPE value;
1703 tree t;
1710 }
1712 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1713 to another fixed-point type. */
1715 static tree
1717 {
1718 FIXED_VALUE_TYPE value;
1719 tree t;
1726 /* Propagate overflow flags. */
1730 }
1732 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
1733 to a fixed-point type. */
1735 static tree
1737 {
1738 FIXED_VALUE_TYPE value;
1739 tree t;
1748 /* Propagate overflow flags. */
1752 }
1754 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1755 to a fixed-point type. */
1757 static tree
1759 {
1760 FIXED_VALUE_TYPE value;
1761 tree t;
1769 /* Propagate overflow flags. */
1773 }
1775 /* Attempt to fold type conversion operation CODE of expression ARG1 to
1776 type TYPE. If no simplification can be done return NULL_TREE. */
1778 static tree
1780 {
1786 {
1793 }
1795 {
1802 }
1804 {
1811 }
1813 }
1815 /* Construct a vector of zero elements of vector type TYPE. */
1817 static tree
1819 {
1830 }
1832 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
1834 bool
1836 {
1851 {
1870 }
1871 }
1873 /* Convert expression ARG to type TYPE. Used by the middle-end for
1874 simple conversions in preference to calling the front-end's convert. */
1876 tree
1878 {
1880 tree tem;
1894 {
1897 /* Handle conversions between pointers to different address spaces. */
1902 /* fall through */
1907 {
1911 }
1925 {
1929 }
1931 {
1935 }
1937 {
1941 }
1944 {
1962 }
1967 {
1971 }
1974 {
1988 }
1992 {
2001 integer_zero_node));
2003 {
2007 {
2013 }
2021 }
2025 }
2043 }
2044 fold_convert_exit:
2047 }
2048 \f
2049 /* Return false if expr can be assumed not to be an lvalue, true
2050 otherwise. */
2052 static bool
2054 {
2055 /* We only need to wrap lvalue tree codes. */
2057 {
2089 /* Assume the worst for front-end tree codes. */
2093 }
2096 }
2098 /* Return an expr equal to X but certainly not valid as an lvalue. */
2100 tree
2102 {
2103 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2104 us. */
2113 }
2115 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2116 Zero means allow extended lvalues. */
2120 /* When pedantic, return an expr equal to X but certainly not valid as a
2121 pedantic lvalue. Otherwise, return X. */
2123 static tree
2125 {
2130 }
2131 \f
2132 /* Given a tree comparison code, return the code that is the logical inverse
2133 of the given code. It is not safe to do this for floating-point
2134 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2135 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2137 enum tree_code
2139 {
2144 {
2175 }
2176 }
2178 /* Similar, but return the comparison that results if the operands are
2179 swapped. This is safe for floating-point. */
2181 enum tree_code
2183 {
2185 {
2211 }
2212 }
2215 /* Convert a comparison tree code from an enum tree_code representation
2216 into a compcode bit-based encoding. This function is the inverse of
2217 compcode_to_comparison. */
2219 static enum comparison_code
2221 {
2223 {
2254 }
2255 }
2257 /* Convert a compcode bit-based encoding of a comparison operator back
2258 to GCC's enum tree_code representation. This function is the
2259 inverse of comparison_to_compcode. */
2261 static enum tree_code
2263 {
2265 {
2296 }
2297 }
2299 /* Return a tree for the comparison which is the combination of
2300 doing the AND or OR (depending on CODE) of the two operations LCODE
2301 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2302 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2303 if this makes the transformation invalid. */
2305 tree
2310 {
2317 {
2328 }
2331 {
2332 /* Eliminate unordered comparisons, as well as LTGT and ORD
2333 which are not used unless the mode has NaNs. */
2339 }
2341 {
2342 /* Check that the original operation and the optimized ones will trap
2343 under the same condition. */
2354 /* In a short-circuited boolean expression the LHS might be
2355 such that the RHS, if evaluated, will never trap. For
2356 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2357 if neither x nor y is NaN. (This is a mixed blessing: for
2358 example, the expression above will never trap, hence
2359 optimizing it to x < y would be invalid). */
2364 /* If the comparison was short-circuited, and only the RHS
2365 trapped, we may now generate a spurious trap. */
2370 /* If we changed the conditions that cause a trap, we lose. */
2373 }
2379 else
2380 {
2385 }
2386 }
2387 \f
2388 /* Return nonzero if two operands (typically of the same tree node)
2389 are necessarily equal. If either argument has side-effects this
2390 function returns zero. FLAGS modifies behavior as follows:
2392 If OEP_ONLY_CONST is set, only return nonzero for constants.
2393 This function tests whether the operands are indistinguishable;
2394 it does not test whether they are equal using C's == operation.
2395 The distinction is important for IEEE floating point, because
2396 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2397 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2399 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2400 even though it may hold multiple values during a function.
2401 This is because a GCC tree node guarantees that nothing else is
2402 executed between the evaluation of its "operands" (which may often
2403 be evaluated in arbitrary order). Hence if the operands themselves
2404 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2405 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2406 unset means assuming isochronic (or instantaneous) tree equivalence.
2407 Unless comparing arbitrary expression trees, such as from different
2408 statements, this flag can usually be left unset.
2410 If OEP_PURE_SAME is set, then pure functions with identical arguments
2411 are considered the same. It is used when the caller has other ways
2412 to ensure that global memory is unchanged in between. */
2414 int
2416 {
2417 /* If either is ERROR_MARK, they aren't equal. */
2423 /* Similar, if either does not have a type (like a released SSA name),
2424 they aren't equal. */
2428 /* Check equality of integer constants before bailing out due to
2429 precision differences. */
2433 /* If both types don't have the same signedness, then we can't consider
2434 them equal. We must check this before the STRIP_NOPS calls
2435 because they may change the signedness of the arguments. As pointers
2436 strictly don't have a signedness, require either two pointers or
2437 two non-pointers as well. */
2442 /* We cannot consider pointers to different address space equal. */
2448 /* If both types don't have the same precision, then it is not safe
2449 to strip NOPs. */
2456 /* In case both args are comparisons but with different comparison
2457 code, try to swap the comparison operands of one arg to produce
2458 a match and compare that variant. */
2462 {
2470 }
2473 /* This is needed for conversions and for COMPONENT_REF.
2474 Might as well play it safe and always test this. */
2480 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2481 We don't care about side effects in that case because the SAVE_EXPR
2482 takes care of that for us. In all other cases, two expressions are
2483 equal if they have no side effects. If we have two identical
2484 expressions with side effects that should be treated the same due
2485 to the only side effects being identical SAVE_EXPR's, that will
2486 be detected in the recursive calls below. */
2492 /* Next handle constant cases, those for which we can return 1 even
2493 if ONLY_CONST is set. */
2496 {
2511 {
2512 /* If we do not distinguish between signed and unsigned zero,
2513 consider them equal. */
2516 }
2520 {
2526 {
2528 flags))
2532 }
2535 }
2539 flags)
2541 flags));
2554 }
2559 /* Define macros to test an operand from arg0 and arg1 for equality and a
2560 variant that allows null and views null as being different from any
2561 non-null value. In the latter case, if either is null, the both
2562 must be; otherwise, do the normal comparison. */
2563 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2564 TREE_OPERAND (arg1, N), flags)
2566 #define OP_SAME_WITH_NULL(N) \
2567 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2568 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2571 {
2573 /* Two conversions are equal only if signedness and modes match. */
2575 {
2576 CASE_CONVERT:
2584 }
2594 /* For commutative ops, allow the other order. */
2602 /* If either of the pointer (or reference) expressions we are
2603 dereferencing contain a side effect, these cannot be equal. */
2609 {
2619 /* Operands 2 and 3 may be null.
2620 Compare the array index by value if it is constant first as we
2621 may have different types but same value here. */
2630 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
2631 may be NULL when we're called to compare MEM_EXPRs. */
2641 }
2645 {
2660 /* Otherwise take into account this is a commutative operation. */
2671 }
2675 {
2677 /* If the CALL_EXPRs call different functions, then they
2678 clearly can not be equal. */
2680 flags))
2683 {
2687 else
2691 }
2693 /* Now see if all the arguments are the same. */
2694 {
2705 /* If we get here and both argument lists are exhausted
2706 then the CALL_EXPRs are equal. */
2708 }
2711 }
2714 /* Consider __builtin_sqrt equal to sqrt. */
2722 }
2724 #undef OP_SAME
2725 #undef OP_SAME_WITH_NULL
2726 }
2727 \f
2728 /* Similar to operand_equal_p, but see if ARG0 might have been made by
2729 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
2731 When in doubt, return 0. */
2733 static int
2735 {
2747 /* Discard any conversions that don't change the modes of ARG0 and ARG1
2748 and see if the inner values are the same. This removes any
2749 signedness comparison, which doesn't matter here. */
2756 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
2757 actual comparison operand, ARG0.
2759 First throw away any conversions to wider types
2760 already present in the operands. */
2769 {
2772 /* Make sure shorter operand is extended the right way
2773 to match the longer operand. */
2779 }
2782 }
2783 \f
2784 /* See if ARG is an expression that is either a comparison or is performing
2785 arithmetic on comparisons. The comparisons must only be comparing
2786 two different values, which will be stored in *CVAL1 and *CVAL2; if
2787 they are nonzero it means that some operands have already been found.
2788 No variables may be used anywhere else in the expression except in the
2789 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2790 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2792 If this is true, return 1. Otherwise, return zero. */
2794 static int
2796 {
2800 /* We can handle some of the tcc_expression cases here. */
2810 {
2811 /* If we've already found a CVAL1 or CVAL2, this expression is
2812 two complex to handle. */
2818 }
2821 {
2844 /* First see if we can handle the first operand, then the second. For
2845 the second operand, we know *CVAL1 can't be zero. It must be that
2846 one side of the comparison is each of the values; test for the
2847 case where this isn't true by failing if the two operands
2848 are the same. */
2857 ;
2861 ;
2862 else
2866 ;
2870 ;
2871 else
2878 }
2879 }
2880 \f
2881 /* ARG is a tree that is known to contain just arithmetic operations and
2882 comparisons. Evaluate the operations in the tree substituting NEW0 for
2883 any occurrence of OLD0 as an operand of a comparison and likewise for
2884 NEW1 and OLD1. */
2886 static tree
2889 {
2894 /* We can handle some of the tcc_expression cases here. */
2902 {
2917 {
2936 }
2937 /* Fall through - ??? */
2940 {
2944 /* We need to check both for exact equality and tree equality. The
2945 former will be true if the operand has a side-effect. In that
2946 case, we know the operand occurred exactly once. */
2959 }
2963 }
2964 }
2965 \f
2966 /* Return a tree for the case when the result of an expression is RESULT
2967 converted to TYPE and OMITTED was previously an operand of the expression
2968 but is now not needed (e.g., we folded OMITTED * 0).
2970 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2971 the conversion of RESULT to TYPE. */
2973 tree
2975 {
2978 /* If the resulting operand is an empty statement, just return the omitted
2979 statement casted to void. */
2981 {
2984 }
2987 {
2990 }
2994 omit_one_operand_exit:
2997 }
2999 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3001 static tree
3003 tree omitted)
3004 {
3007 /* If the resulting operand is an empty statement, just return the omitted
3008 statement casted to void. */
3010 {
3013 }
3016 {
3019 }
3023 pedantic_omit_one_operand_exit:
3026 }
3028 /* Return a tree for the case when the result of an expression is RESULT
3029 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3030 of the expression but are now not needed.
3032 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3033 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3034 evaluated before OMITTED2. Otherwise, if neither has side effects,
3035 just do the conversion of RESULT to TYPE. */
3037 tree
3040 {
3044 {
3047 }
3049 {
3052 }
3055 }
3057 \f
3058 /* Return a simplified tree node for the truth-negation of ARG. This
3059 never alters ARG itself. We assume that ARG is an operation that
3060 returns a truth value (0 or 1).
3062 FIXME: one would think we would fold the result, but it causes
3063 problems with the dominator optimizer. */
3065 tree
3067 {
3072 /* If this is a comparison, we can simply invert it, except for
3073 floating-point non-equality comparisons, in which case we just
3074 enclose a TRUTH_NOT_EXPR around what we have. */
3077 {
3080 && flag_trapping_math
3092 }
3095 {
3124 /* Here we can invert either operand. We invert the first operand
3125 unless the second operand is a TRUTH_NOT_EXPR in which case our
3126 result is the XOR of the first operand with the inside of the
3127 negation of the second operand. */
3132 else
3166 {
3177 /* A COND_EXPR may have a throw as one operand, which
3178 then has void type. Just leave void operands
3179 as they are. */
3186 }
3203 CASE_CONVERT:
3205 {
3208 }
3210 /* ... fall through ... */
3241 }
3247 }
3249 /* Return a simplified tree node for the truth-negation of ARG. This
3250 never alters ARG itself. We assume that ARG is an operation that
3251 returns a truth value (0 or 1).
3253 FIXME: one would think we would fold the result, but it causes
3254 problems with the dominator optimizer. */
3256 tree
3258 {
3259 tree tem;
3266 {
3269 }
3272 }
3274 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3275 operands are another bit-wise operation with a common input. If so,
3276 distribute the bit operations to save an operation and possibly two if
3277 constants are involved. For example, convert
3278 (A | B) & (A | C) into A | (B & C)
3279 Further simplification will occur if B and C are constants.
3281 If this optimization cannot be done, 0 will be returned. */
3283 static tree
3286 {
3287 tree common;
3297 {
3301 }
3303 {
3307 }
3309 {
3313 }
3315 {
3319 }
3320 else
3328 }
3330 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3331 with code CODE. This optimization is unsafe. */
3332 static tree
3335 {
3339 /* (A / C) +- (B / C) -> (A +- B) / C. */
3349 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3354 {
3366 }
3369 }
3370 \f
3371 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3372 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3374 static tree
3377 {
3381 {
3388 }
3403 }
3405 /* Optimize a bit-field compare.
3407 There are two cases: First is a compare against a constant and the
3408 second is a comparison of two items where the fields are at the same
3409 bit position relative to the start of a chunk (byte, halfword, word)
3410 large enough to contain it. In these cases we can avoid the shift
3411 implicit in bitfield extractions.
3413 For constants, we emit a compare of the shifted constant with the
3414 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3415 compared. For two fields at the same position, we do the ANDs with the
3416 similar mask and compare the result of the ANDs.
3418 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3419 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3420 are the left and right operands of the comparison, respectively.
3422 If the optimization described above can be done, we return the resulting
3423 tree. Otherwise we return zero. */
3425 static tree
3428 {
3437 tree mask;
3438 tree offset;
3440 /* Get all the information about the extractions being done. If the bit size
3441 if the same as the size of the underlying object, we aren't doing an
3442 extraction at all and so can do nothing. We also don't want to
3443 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3444 then will no longer be able to replace it. */
3452 {
3453 /* If this is not a constant, we can only do something if bit positions,
3454 sizes, and signedness are the same. */
3462 }
3464 /* See if we can find a mode to refer to this field. We should be able to,
3465 but fail if we can't. */
3474 /* Set signed and unsigned types of the precision of this mode for the
3475 shifts below. */
3479 /* Compute the bit position and size for the new reference and our offset
3480 within it. If the new reference is the same size as the original, we
3481 won't optimize anything, so return zero. */
3491 /* Make the mask to be used against the extracted field. */
3498 /* If not comparing with constant, just rework the comparison
3499 and return. */
3503 unsigned_type,
3506 mask),
3509 unsigned_type,
3512 mask));
3514 /* Otherwise, we are handling the constant case. See if the constant is too
3515 big for the field. Warn and return a tree of for 0 (false) if so. We do
3516 this not only for its own sake, but to avoid having to test for this
3517 error case below. If we didn't, we might generate wrong code.
3519 For unsigned fields, the constant shifted right by the field length should
3520 be all zero. For signed fields, the high-order bits should agree with
3521 the sign bit. */
3524 {
3529 {
3533 }
3534 }
3535 else
3536 {
3541 {
3545 }
3546 }
3548 /* Single-bit compares should always be against zero. */
3550 {
3553 }
3555 /* Make a new bitfield reference, shift the constant over the
3556 appropriate number of bits and mask it with the computed mask
3557 (in case this was a signed field). If we changed it, make a new one. */
3560 {
3563 }
3573 rhs);
3576 }
3577 \f
3578 /* Subroutine for fold_truthop: decode a field reference.
3580 If EXP is a comparison reference, we return the innermost reference.
3582 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3583 set to the starting bit number.
3585 If the innermost field can be completely contained in a mode-sized
3586 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3588 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3589 otherwise it is not changed.
3591 *PUNSIGNEDP is set to the signedness of the field.
3593 *PMASK is set to the mask used. This is either contained in a
3594 BIT_AND_EXPR or derived from the width of the field.
3596 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3598 Return 0 if this is not a component reference or is one that we can't
3599 do anything with. */
3601 static tree
3606 {
3610 tree unsigned_type;
3613 /* All the optimizations using this function assume integer fields.
3614 There are problems with FP fields since the type_for_size call
3615 below can fail for, e.g., XFmode. */
3619 /* We are interested in the bare arrangement of bits, so strip everything
3620 that doesn't affect the machine mode. However, record the type of the
3621 outermost expression if it may matter below. */
3628 {
3634 }
3643 /* If the number of bits in the reference is the same as the bitsize of
3644 the outer type, then the outer type gives the signedness. Otherwise
3645 (in case of a small bitfield) the signedness is unchanged. */
3649 /* Compute the mask to access the bitfield. */
3658 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3666 }
3668 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
3669 bit positions. */
3671 static int
3673 {
3676 tree tmask;
3680 return
3687 }
3689 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3690 represents the sign bit of EXP's type. If EXP represents a sign
3691 or zero extension, also test VAL against the unextended type.
3692 The return value is the (sub)expression whose sign bit is VAL,
3693 or NULL_TREE otherwise. */
3695 static tree
3697 {
3701 tree t;
3703 /* Tree EXP must have an integral type. */
3708 /* Tree VAL must be an integer constant. */
3715 {
3722 }
3723 else
3724 {
3731 }
3733 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
3734 treat VAL as if it were unsigned. */
3739 /* Handle extension from a narrower type. */
3745 }
3747 /* Subroutine for fold_truthop: determine if an operand is simple enough
3748 to be evaluated unconditionally. */
3750 static int
3752 {
3753 /* Strip any conversions that don't change the machine mode. */
3762 /* Don't regard global variables as simple. They may be
3763 allocated in ways unknown to the compiler (shared memory,
3764 #pragma weak, etc). */
3767 /* Loading a static variable is unduly expensive, but global
3768 registers aren't expensive. */
3770 }
3771 \f
3772 /* The following functions are subroutines to fold_range_test and allow it to
3773 try to change a logical combination of comparisons into a range test.
3775 For example, both
3776 X == 2 || X == 3 || X == 4 || X == 5
3777 and
3778 X >= 2 && X <= 5
3779 are converted to
3780 (unsigned) (X - 2) <= 3
3782 We describe each set of comparisons as being either inside or outside
3783 a range, using a variable named like IN_P, and then describe the
3784 range with a lower and upper bound. If one of the bounds is omitted,
3785 it represents either the highest or lowest value of the type.
3787 In the comments below, we represent a range by two numbers in brackets
3788 preceded by a "+" to designate being inside that range, or a "-" to
3789 designate being outside that range, so the condition can be inverted by
3790 flipping the prefix. An omitted bound is represented by a "-". For
3791 example, "- [-, 10]" means being outside the range starting at the lowest
3792 possible value and ending at 10, in other words, being greater than 10.
3793 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
3794 always false.
3796 We set up things so that the missing bounds are handled in a consistent
3797 manner so neither a missing bound nor "true" and "false" need to be
3798 handled using a special case. */
3800 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
3801 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
3802 and UPPER1_P are nonzero if the respective argument is an upper bound
3803 and zero for a lower. TYPE, if nonzero, is the type of the result; it
3804 must be specified for a comparison. ARG1 will be converted to ARG0's
3805 type if both are specified. */
3807 static tree
3810 {
3811 tree tem;
3815 /* If neither arg represents infinity, do the normal operation.
3816 Else, if not a comparison, return infinity. Else handle the special
3817 comparison rules. Note that most of the cases below won't occur, but
3818 are handled for consistency. */
3821 {
3826 }
3831 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
3832 for neither. In real maths, we cannot assume open ended ranges are
3833 the same. But, this is computer arithmetic, where numbers are finite.
3834 We can therefore make the transformation of any unbounded range with
3835 the value Z, Z being greater than any representable number. This permits
3836 us to treat unbounded ranges as equal. */
3840 {
3861 }
3864 }
3865 \f
3866 /* Given EXP, a logical expression, set the range it is testing into
3867 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
3868 actually being tested. *PLOW and *PHIGH will be made of the same
3869 type as the returned expression. If EXP is not a comparison, we
3870 will most likely not be returning a useful value and range. Set
3871 *STRICT_OVERFLOW_P to true if the return value is only valid
3872 because signed overflow is undefined; otherwise, do not change
3873 *STRICT_OVERFLOW_P. */
3875 tree
3878 {
3886 /* Start with simply saying "EXP != 0" and then look at the code of EXP
3887 and see if we can refine the range. Some of the cases below may not
3888 happen, but it doesn't seem worth worrying about this. We "continue"
3889 the outer loop when we've changed something; otherwise we "break"
3890 the switch, which will "break" the while. */
3896 {
3901 {
3913 }
3916 {
3923 /* We can only do something if the range is testing for zero
3924 and if the second operand is an integer constant. Note that
3925 saying something is "in" the range we make is done by
3926 complementing IN_P since it will set in the initial case of
3927 being not equal to zero; "out" is leaving it alone. */
3934 {
3955 }
3957 /* If this is an unsigned comparison, we also know that EXP is
3958 greater than or equal to zero. We base the range tests we make
3959 on that fact, so we record it here so we can parse existing
3960 range tests. We test arg0_type since often the return type
3961 of, e.g. EQ_EXPR, is boolean. */
3963 {
3967 NULL_TREE))
3972 /* If the high bound is missing, but we have a nonzero low
3973 bound, reverse the range so it goes from zero to the low bound
3974 minus 1. */
3976 {
3981 }
3982 }
3988 /* (-x) IN [a,b] -> x in [-b, -a] */
4000 /* ~ X -> -X - 1 */
4010 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4011 move a constant to the other side. */
4016 /* If EXP is signed, any overflow in the computation is undefined,
4017 so we don't worry about it so long as our computations on
4018 the bounds don't overflow. For unsigned, overflow is defined
4019 and this is exactly the right thing. */
4031 /* Check for an unsigned range which has wrapped around the maximum
4032 value thus making n_high < n_low, and normalize it. */
4034 {
4040 /* If the range is of the form +/- [ x+1, x ], we won't
4041 be able to normalize it. But then, it represents the
4042 whole range or the empty set, so make it
4043 +/- [ -, - ]. */
4047 else
4049 }
4050 else
4074 /* If we're converting arg0 from an unsigned type, to exp,
4075 a signed type, we will be doing the comparison as unsigned.
4076 The tests above have already verified that LOW and HIGH
4077 are both positive.
4079 So we have to ensure that we will handle large unsigned
4080 values the same way that the current signed bounds treat
4081 negative values. */
4084 {
4085 tree high_positive;
4086 tree equiv_type;
4087 /* For fixed-point modes, we need to pass the saturating flag
4088 as the 2nd parameter. */
4093 else
4097 /* A range without an upper bound is, naturally, unbounded.
4098 Since convert would have cropped a very large value, use
4099 the max value for the destination type. */
4100 high_positive
4107 high_positive),
4110 /* If the low bound is specified, "and" the range with the
4111 range for which the original unsigned value will be
4112 positive. */
4114 {
4118 integer_zero_node),
4119 high_positive))
4123 }
4124 else
4125 {
4126 /* Otherwise, "or" the range with the range of the input
4127 that will be interpreted as negative. */
4131 integer_zero_node),
4132 high_positive))
4136 }
4137 }
4145 }
4148 }
4150 /* If EXP is a constant, we can evaluate whether this is true or false. */
4152 {
4159 }
4163 }
4164 \f
4165 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4166 type, TYPE, return an expression to test if EXP is in (or out of, depending
4167 on IN_P) the range. Return 0 if the test couldn't be created. */
4169 tree
4172 {
4175 #ifdef HAVE_canonicalize_funcptr_for_compare
4176 /* Disable this optimization for function pointer expressions
4177 on targets that require function pointer canonicalization. */
4182 #endif
4185 {
4191 }
4209 {
4211 {
4215 }
4217 }
4219 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4221 {
4223 HOST_WIDE_INT hi;
4228 {
4231 }
4232 else
4233 {
4236 }
4239 {
4241 {
4244 etype
4246 else
4249 }
4252 }
4253 }
4255 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4256 This requires wrap-around arithmetics for the type of the expression.
4257 First make sure that arithmetics in this type is valid, then make sure
4258 that it wraps around. */
4264 {
4267 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4268 for the type in question, as we rely on this here. */
4278 else
4280 }
4290 {
4292 {
4299 }
4301 }
4309 }
4310 \f
4311 /* Return the predecessor of VAL in its type, handling the infinite case. */
4313 static tree
4315 {
4321 else
4323 }
4325 /* Return the successor of VAL in its type, handling the infinite case. */
4327 static tree
4329 {
4335 else
4337 }
4339 /* Given two ranges, see if we can merge them into one. Return 1 if we
4340 can, 0 if we can't. Set the output range into the specified parameters. */
4342 bool
4345 {
4349 tree tem;
4359 /* Make range 0 be the range that starts first, or ends last if they
4360 start at the same value. Swap them if it isn't. */
4363 || (lowequal
4366 {
4370 }
4372 /* Now flag two cases, whether the ranges are disjoint or whether the
4373 second range is totally subsumed in the first. Note that the tests
4374 below are simplified by the ones above. */
4380 /* We now have four cases, depending on whether we are including or
4381 excluding the two ranges. */
4383 {
4384 /* If they don't overlap, the result is false. If the second range
4385 is a subset it is the result. Otherwise, the range is from the start
4386 of the second to the end of the first. */
4391 else
4393 }
4396 {
4397 /* If they don't overlap, the result is the first range. If they are
4398 equal, the result is false. If the second range is a subset of the
4399 first, and the ranges begin at the same place, we go from just after
4400 the end of the second range to the end of the first. If the second
4401 range is not a subset of the first, or if it is a subset and both
4402 ranges end at the same place, the range starts at the start of the
4403 first range and ends just before the second range.
4404 Otherwise, we can't describe this as a single range. */
4410 {
4415 {
4416 /* We are in the weird situation where high0 > high1 but
4417 high1 has no successor. Punt. */
4419 }
4420 }
4422 {
4427 {
4428 /* low0 < low1 but low1 has no predecessor. Punt. */
4430 }
4431 }
4432 else
4434 }
4437 {
4438 /* If they don't overlap, the result is the second range. If the second
4439 is a subset of the first, the result is false. Otherwise,
4440 the range starts just after the first range and ends at the
4441 end of the second. */
4446 else
4447 {
4452 {
4453 /* high1 > high0 but high0 has no successor. Punt. */
4455 }
4456 }
4457 }
4459 else
4460 {
4461 /* The case where we are excluding both ranges. Here the complex case
4462 is if they don't overlap. In that case, the only time we have a
4463 range is if they are adjacent. If the second is a subset of the
4464 first, the result is the first. Otherwise, the range to exclude
4465 starts at the beginning of the first range and ends at the end of the
4466 second. */
4468 {
4473 else
4474 {
4475 /* Canonicalize - [min, x] into - [-, x]. */
4478 {
4483 /* FALLTHROUGH */
4496 }
4498 /* Canonicalize - [x, max] into - [x, -]. */
4501 {
4506 /* FALLTHROUGH */
4521 }
4523 /* The ranges might be also adjacent between the maximum and
4524 minimum values of the given type. For
4525 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4526 return + [x + 1, y - 1]. */
4528 {
4535 }
4536 else
4538 }
4539 }
4542 else
4544 }
4548 }
4549 \f
4551 /* Subroutine of fold, looking inside expressions of the form
4552 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4553 of the COND_EXPR. This function is being used also to optimize
4554 A op B ? C : A, by reversing the comparison first.
4556 Return a folded expression whose code is not a COND_EXPR
4557 anymore, or NULL_TREE if no folding opportunity is found. */
4559 static tree
4562 {
4567 tree tem;
4572 /* If we have A op 0 ? A : -A, consider applying the following
4573 transformations:
4575 A == 0? A : -A same as -A
4576 A != 0? A : -A same as A
4577 A >= 0? A : -A same as abs (A)
4578 A > 0? A : -A same as abs (A)
4579 A <= 0? A : -A same as -abs (A)
4580 A < 0? A : -A same as -abs (A)
4582 None of these transformations work for modes with signed
4583 zeros. If A is +/-0, the first two transformations will
4584 change the sign of the result (from +0 to -0, or vice
4585 versa). The last four will fix the sign of the result,
4586 even though the original expressions could be positive or
4587 negative, depending on the sign of A.
4589 Note that all these transformations are correct if A is
4590 NaN, since the two alternatives (A and -A) are also NaNs. */
4597 /* In the case that A is of the form X-Y, '-A' (arg2) may
4598 have already been folded to Y-X, check for that. */
4606 {
4620 /* Fall through. */
4642 }
4644 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4645 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4646 both transformations are correct when A is NaN: A != 0
4647 is then true, and A == 0 is false. */
4651 {
4656 }
4658 /* Try some transformations of A op B ? A : B.
4660 A == B? A : B same as B
4661 A != B? A : B same as A
4662 A >= B? A : B same as max (A, B)
4663 A > B? A : B same as max (B, A)
4664 A <= B? A : B same as min (A, B)
4665 A < B? A : B same as min (B, A)
4667 As above, these transformations don't work in the presence
4668 of signed zeros. For example, if A and B are zeros of
4669 opposite sign, the first two transformations will change
4670 the sign of the result. In the last four, the original
4671 expressions give different results for (A=+0, B=-0) and
4672 (A=-0, B=+0), but the transformed expressions do not.
4674 The first two transformations are correct if either A or B
4675 is a NaN. In the first transformation, the condition will
4676 be false, and B will indeed be chosen. In the case of the
4677 second transformation, the condition A != B will be true,
4678 and A will be chosen.
4680 The conversions to max() and min() are not correct if B is
4681 a number and A is not. The conditions in the original
4682 expressions will be false, so all four give B. The min()
4683 and max() versions would give a NaN instead. */
4686 /* Avoid these transformations if the COND_EXPR may be used
4687 as an lvalue in the C++ front-end. PR c++/19199. */
4688 && (in_gimple_form
4693 {
4698 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4700 {
4704 }
4707 {
4716 /* In C++ a ?: expression can be an lvalue, so put the
4717 operand which will be used if they are equal first
4718 so that we can convert this back to the
4719 corresponding COND_EXPR. */
4721 {
4730 }
4737 {
4746 }
4761 }
4762 }
4764 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
4765 we might still be able to simplify this. For example,
4766 if C1 is one less or one more than C2, this might have started
4767 out as a MIN or MAX and been transformed by this function.
4768 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
4774 {
4778 /* We can replace A with C1 in this case. */
4783 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
4784 MIN_EXPR, to preserve the signedness of the comparison. */
4786 OEP_ONLY_CONST)
4790 OEP_ONLY_CONST))
4791 {
4794 arg2));
4797 }
4801 /* If C1 is C2 - 1, this is min(A, C2), with the same care
4802 as above. */
4804 OEP_ONLY_CONST)
4808 OEP_ONLY_CONST))
4809 {
4812 arg2));
4815 }
4819 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
4820 MAX_EXPR, to preserve the signedness of the comparison. */
4822 OEP_ONLY_CONST)
4826 OEP_ONLY_CONST))
4827 {
4830 arg2));
4832 }
4836 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
4838 OEP_ONLY_CONST)
4842 OEP_ONLY_CONST))
4843 {
4846 arg2));
4848 }
4854 }
4857 }
4860 \f
4861 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
4862 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
4863 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
4864 false) >= 2)
4865 #endif
4867 /* EXP is some logical combination of boolean tests. See if we can
4868 merge it into some range test. Return the new tree if so. */
4870 static tree
4873 {
4881 tree tem;
4885 /* If this is an OR operation, invert both sides; we will invert
4886 again at the end. */
4890 /* If both expressions are the same, if we can merge the ranges, and we
4891 can build the range test, return it or it inverted. If one of the
4892 ranges is always true or always false, consider it to be the same
4893 expression as the other. */
4901 {
4905 }
4907 /* On machines where the branch cost is expensive, if this is a
4908 short-circuited branch and the underlying object on both sides
4909 is the same, make a non-short-circuit operation. */
4915 {
4916 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
4917 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
4918 which cases we can't do this. */
4920 {
4926 }
4930 {
4939 {
4942 WARN_STRICT_OVERFLOW_COMPARISON);
4948 }
4949 }
4950 }
4953 }
4954 \f
4955 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
4956 bit value. Arrange things so the extra bits will be set to zero if and
4957 only if C is signed-extended to its full width. If MASK is nonzero,
4958 it is an INTEGER_CST that should be AND'ed with the extra bits. */
4960 static tree
4962 {
4965 tree temp;
4970 /* We work by getting just the sign bit into the low-order bit, then
4971 into the high-order bit, then sign-extend. We then XOR that value
4972 with C. */
4976 /* We must use a signed type in order to get an arithmetic right shift.
4977 However, we must also avoid introducing accidental overflows, so that
4978 a subsequent call to integer_zerop will work. Hence we must
4979 do the type conversion here. At this point, the constant is either
4980 zero or one, and the conversion to a signed type can never overflow.
4981 We could get an overflow if this conversion is done anywhere else. */
4991 /* If necessary, convert the type back to match the type of C. */
4997 }
4998 \f
4999 /* For an expression that has the form
5000 (A && B) || ~B
5001 or
5002 (A || B) && ~B,
5003 we can drop one of the inner expressions and simplify to
5004 A || ~B
5005 or
5006 A && ~B
5007 LOC is the location of the resulting expression. OP is the inner
5008 logical operation; the left-hand side in the examples above, while CMPOP
5009 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5010 removing a condition that guards another, as in
5011 (A != NULL && A->...) || A == NULL
5012 which we must not transform. If RHS_ONLY is true, only eliminate the
5013 right-most operand of the inner logical operation. */
5015 static tree
5018 {
5036 {
5039 {
5042 }
5043 }
5045 {
5048 {
5051 }
5052 }
5067 }
5069 /* Find ways of folding logical expressions of LHS and RHS:
5070 Try to merge two comparisons to the same innermost item.
5071 Look for range tests like "ch >= '0' && ch <= '9'".
5072 Look for combinations of simple terms on machines with expensive branches
5073 and evaluate the RHS unconditionally.
5075 For example, if we have p->a == 2 && p->b == 4 and we can make an
5076 object large enough to span both A and B, we can do this with a comparison
5077 against the object ANDed with the a mask.
5079 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5080 operations to do this with one comparison.
5082 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5083 function and the one above.
5085 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5086 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5088 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5089 two operands.
5091 We return the simplified tree or 0 if no optimization is possible. */
5093 static tree
5096 {
5097 /* If this is the "or" of two comparisons, we can do something if
5098 the comparisons are NE_EXPR. If this is the "and", we can do something
5099 if the comparisons are EQ_EXPR. I.e.,
5100 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5102 WANTED_CODE is this operation code. For single bit fields, we can
5103 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5104 comparison for one-bit fields. */
5126 /* Start by getting the comparison codes. Fail if anything is volatile.
5127 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5128 it were surrounded with a NE_EXPR. */
5137 {
5141 }
5144 {
5148 }
5159 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5162 {
5163 tree result;
5166 {
5171 }
5174 {
5180 }
5181 }
5186 /* If the RHS can be evaluated unconditionally and its operands are
5187 simple, it wins to evaluate the RHS unconditionally on machines
5188 with expensive branches. In this case, this isn't a comparison
5189 that can be merged. Avoid doing this if the RHS is a floating-point
5190 comparison since those can trap. */
5197 {
5198 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5204 {
5210 }
5212 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5218 {
5224 }
5227 {
5229 {
5232 }
5234 }
5235 }
5237 /* See if the comparisons can be merged. Then get all the parameters for
5238 each side. */
5262 /* It must be true that the inner operation on the lhs of each
5263 comparison must be the same if we are to be able to do anything.
5264 Then see if we have constants. If not, the same must be true for
5265 the rhs's. */
5276 else
5279 /* If either comparison code is not correct for our logical operation,
5280 fail. However, we can convert a one-bit comparison against zero into
5281 the opposite comparison against that bit being set in the field. */
5285 {
5287 {
5288 /* Make the left operand unsigned, since we are only interested
5289 in the value of one bit. Otherwise we are doing the wrong
5290 thing below. */
5293 }
5294 else
5296 }
5298 /* This is analogous to the code for l_const above. */
5300 {
5302 {
5305 }
5306 else
5308 }
5310 /* See if we can find a mode that contains both fields being compared on
5311 the left. If we can't, fail. Otherwise, update all constants and masks
5312 to be relative to a field of that size. */
5317 volatilep);
5327 {
5330 }
5338 {
5346 {
5350 }
5351 }
5353 {
5361 {
5365 }
5366 }
5368 /* If the right sides are not constant, do the same for it. Also,
5369 disallow this optimization if a size or signedness mismatch occurs
5370 between the left and right sides. */
5372 {
5375 /* Make sure the two fields on the right
5376 correspond to the left without being swapped. */
5384 volatilep);
5394 {
5397 }
5406 /* Make a mask that corresponds to both fields being compared.
5407 Do this for both items being compared. If the operands are the
5408 same size and the bits being compared are in the same position
5409 then we can do this by masking both and comparing the masked
5410 results. */
5414 {
5427 }
5429 /* There is still another way we can do something: If both pairs of
5430 fields being compared are adjacent, we may be able to make a wider
5431 field containing them both.
5433 Note that we still must mask the lhs/rhs expressions. Furthermore,
5434 the mask must be shifted to account for the shift done by
5435 make_bit_field_ref. */
5440 {
5441 tree type;
5455 /* Convert to the smaller type before masking out unwanted bits. */
5458 {
5460 {
5464 }
5466 {
5470 }
5471 }
5481 }
5484 }
5486 /* Handle the case of comparisons with constants. If there is something in
5487 common between the masks, those bits of the constants must be the same.
5488 If not, the condition is always false. Test for this to avoid generating
5489 incorrect code below. */
5494 {
5496 {
5499 }
5500 else
5501 {
5504 }
5505 }
5507 /* Construct the expression we will return. First get the component
5508 reference we will make. Unless the mask is all ones the width of
5509 that field, perform the mask operation. Then compare with the
5510 merged constant. */
5516 {
5519 }
5524 fold_truthop_exit:
5527 }
5528 \f
5529 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5530 constant. */
5532 static tree
5535 {
5538 tree comp_const;
5539 tree minmax_const;
5541 tree inner;
5552 /* If something does not permit us to optimize, return the original tree. */
5560 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5561 and GT_EXPR, doing the rest with recursive calls using logical
5562 simplifications. */
5564 {
5566 {
5567 tree tem
5574 }
5577 return
5579 optimize_minmax_comparison
5581 optimize_minmax_comparison
5586 /* MAX (X, 0) == 0 -> X <= 0 */
5590 /* MAX (X, 0) == 5 -> X == 5 */
5594 /* MAX (X, 0) == -1 -> false */
5598 /* MIN (X, 0) == 0 -> X >= 0 */
5602 /* MIN (X, 0) == 5 -> false */
5605 else
5606 /* MIN (X, 0) == -1 -> X == -1 */
5611 /* MAX (X, 0) > 0 -> X > 0
5612 MAX (X, 0) > 5 -> X > 5 */
5616 /* MAX (X, 0) > -1 -> true */
5620 /* MIN (X, 0) > 0 -> false
5621 MIN (X, 0) > 5 -> false */
5624 else
5625 /* MIN (X, 0) > -1 -> X > -1 */
5630 }
5631 }
5632 \f
5633 /* T is an integer expression that is being multiplied, divided, or taken a
5634 modulus (CODE says which and what kind of divide or modulus) by a
5635 constant C. See if we can eliminate that operation by folding it with
5636 other operations already in T. WIDE_TYPE, if non-null, is a type that
5637 should be used for the computation if wider than our type.
5639 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5640 (X * 2) + (Y * 4). We must, however, be assured that either the original
5641 expression would not overflow or that overflow is undefined for the type
5642 in the language in question.
5644 If we return a non-null expression, it is an equivalent form of the
5645 original computation, but need not be in the original type.
5647 We set *STRICT_OVERFLOW_P to true if the return values depends on
5648 signed overflow being undefined. Otherwise we do not change
5649 *STRICT_OVERFLOW_P. */
5651 static tree
5654 {
5655 /* To avoid exponential search depth, refuse to allow recursion past
5656 three levels. Beyond that (1) it's highly unlikely that we'll find
5657 something interesting and (2) we've probably processed it before
5658 when we built the inner expression. */
5661 tree ret;
5666 depth++;
5668 depth--;
5671 }
5673 static tree
5676 {
5687 /* Don't deal with constants of zero here; they confuse the code below. */
5697 /* Note that we need not handle conditional operations here since fold
5698 already handles those cases. So just do arithmetic here. */
5700 {
5702 /* For a constant, we can always simplify if we are a multiply
5703 or (for divide and modulus) if it is a multiple of our constant. */
5711 /* If op0 is an expression ... */
5717 /* ... and has wrapping overflow, and its type is smaller
5718 than ctype, then we cannot pass through as widening. */
5724 /* ... or this is a truncation (t is narrower than op0),
5725 then we cannot pass through this narrowing. */
5728 /* ... or signedness changes for division or modulus,
5729 then we cannot pass through this conversion. */
5733 /* ... or has undefined overflow while the converted to
5734 type has not, we cannot do the operation in the inner type
5735 as that would introduce undefined overflow. */
5740 /* Pass the constant down and see if we can make a simplification. If
5741 we can, replace this expression with the inner simplification for
5742 possible later conversion to our or some other type. */
5747 code == MULT_EXPR
5749 strict_overflow_p))))
5754 /* If widening the type changes it from signed to unsigned, then we
5755 must avoid building ABS_EXPR itself as unsigned. */
5757 {
5761 {
5764 }
5766 }
5767 /* If the constant is negative, we cannot simplify this. */
5770 /* FALLTHROUGH */
5778 /* If widening the type changes the signedness, then we can't perform
5779 this optimization as that changes the result. */
5783 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5789 {
5796 }
5800 /* If the second operand is constant, this is a multiplication
5801 or floor division, by a power of two, so we can treat it that
5802 way unless the multiplier or divisor overflows. Signed
5803 left-shift overflow is implementation-defined rather than
5804 undefined in C90, so do not convert signed left shift into
5805 multiplication. */
5808 /* const_binop may not detect overflow correctly,
5809 so check for it explicitly here. */
5814 size_one_node,
5819 ctype,
5821 t1),
5826 /* See if we can eliminate the operation on both sides. If we can, we
5827 can return a new PLUS or MINUS. If we can't, the only remaining
5828 cases where we can do anything are if the second operand is a
5829 constant. */
5835 /* If not multiplication, we can only do this if both operands
5836 are divisible by c. */
5839 {
5844 }
5846 /* If this was a subtraction, negate OP1 and set it to be an addition.
5847 This simplifies the logic below. */
5849 {
5851 /* If OP1 was not easily negatable, the constant may be OP0. */
5853 {
5860 }
5861 }
5866 /* If either OP1 or C are negative, this optimization is not safe for
5867 some of the division and remainder types while for others we need
5868 to change the code. */
5870 {
5878 }
5880 /* If it's a multiply or a division/modulus operation of a multiple
5881 of our constant, do the operation and verify it doesn't overflow. */
5884 {
5887 /* We allow the constant to overflow with wrapping semantics. */
5891 }
5892 else
5895 /* If we have an unsigned type is not a sizetype, we cannot widen
5896 the operation since it will change the result if the original
5897 computation overflowed. */
5903 /* If we were able to eliminate our operation from the first side,
5904 apply our operation to the second side and reform the PLUS. */
5908 /* The last case is if we are a multiply. In that case, we can
5909 apply the distributive law to commute the multiply and addition
5910 if the multiplication of the constants doesn't overflow. */
5916 op1);
5921 /* We have a special case here if we are doing something like
5922 (C * 8) % 4 since we know that's zero. */
5925 /* If the multiplication can overflow we cannot optimize this.
5926 ??? Until we can properly mark individual operations as
5927 not overflowing we need to treat sizetype special here as
5928 stor-layout relies on this opimization to make
5929 DECL_FIELD_BIT_OFFSET always a constant. */
5935 {
5938 }
5940 /* ... fall through ... */
5944 /* If we can extract our operation from the LHS, do so and return a
5945 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5946 do something only if the second operand is a constant. */
5960 /* If these are the same operation types, we can associate them
5961 assuming no overflow. */
5974 /* If these operations "cancel" each other, we have the main
5975 optimizations of this pass, which occur when either constant is a
5976 multiple of the other, in which case we replace this with either an
5977 operation or CODE or TCODE.
5979 If we have an unsigned type that is not a sizetype, we cannot do
5980 this since it will change the result if the original computation
5981 overflowed. */
5989 {
5991 {
5998 }
6000 {
6007 }
6008 }
6013 }
6016 }
6017 \f
6018 /* Return a node which has the indicated constant VALUE (either 0 or
6019 1), and is of the indicated TYPE. */
6021 tree
6023 {
6028 else
6030 }
6033 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6034 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6035 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6036 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6037 COND is the first argument to CODE; otherwise (as in the example
6038 given here), it is the second argument. TYPE is the type of the
6039 original expression. Return NULL_TREE if no simplification is
6040 possible. */
6042 static tree
6047 {
6055 {
6059 /* If this operand throws an expression, then it does not make
6060 sense to try to perform a logical or arithmetic operation
6061 involving it. */
6066 }
6067 else
6068 {
6073 }
6075 /* This transformation is only worthwhile if we don't have to wrap ARG
6076 in a SAVE_EXPR and the operation can be simplified on at least one
6077 of the branches once its pushed inside the COND_EXPR. */
6085 {
6089 else
6091 }
6093 {
6097 else
6099 }
6101 /* Check that we have simplified at least one of the branches. */
6106 }
6108 \f
6109 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6111 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6112 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6113 ADDEND is the same as X.
6115 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6116 and finite. The problematic cases are when X is zero, and its mode
6117 has signed zeros. In the case of rounding towards -infinity,
6118 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6119 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6121 bool
6123 {
6127 /* Don't allow the fold with -fsignaling-nans. */
6131 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6135 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6140 /* The mode has signed zeros, and we have to honor their sign.
6141 In this situation, there is only one case we can return true for.
6142 X - 0 is the same as X unless rounding towards -infinity is
6143 supported. */
6145 }
6147 /* Subroutine of fold() that checks comparisons of built-in math
6148 functions against real constants.
6150 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6151 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6152 is the type of the result and ARG0 and ARG1 are the operands of the
6153 comparison. ARG1 must be a TREE_REAL_CST.
6155 The function returns the constant folded tree if a simplification
6156 can be made, and NULL_TREE otherwise. */
6158 static tree
6162 {
6163 REAL_VALUE_TYPE c;
6166 {
6172 {
6173 /* sqrt(x) < y is always false, if y is negative. */
6177 /* sqrt(x) > y is always true, if y is negative and we
6178 don't care about NaNs, i.e. negative values of x. */
6182 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6185 }
6187 {
6188 REAL_VALUE_TYPE c2;
6194 {
6195 /* sqrt(x) > y is x == +Inf, when y is very large. */
6200 /* sqrt(x) > y is always false, when y is very large
6201 and we don't care about infinities. */
6203 }
6205 /* sqrt(x) > c is the same as x > c*c. */
6208 }
6210 {
6211 REAL_VALUE_TYPE c2;
6217 {
6218 /* sqrt(x) < y is always true, when y is a very large
6219 value and we don't care about NaNs or Infinities. */
6223 /* sqrt(x) < y is x != +Inf when y is very large and we
6224 don't care about NaNs. */
6229 /* sqrt(x) < y is x >= 0 when y is very large and we
6230 don't care about Infinities. */
6235 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6244 dconst0)),
6247 c2)));
6248 }
6250 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6255 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6258 {
6263 dconst0)),
6266 c2)));
6267 }
6268 }
6269 }
6272 }
6274 /* Subroutine of fold() that optimizes comparisons against Infinities,
6275 either +Inf or -Inf.
6277 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6278 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6279 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6281 The function returns the constant folded tree if a simplification
6282 can be made, and NULL_TREE otherwise. */
6284 static tree
6287 {
6289 REAL_VALUE_TYPE max;
6290 tree temp;
6295 /* For negative infinity swap the sense of the comparison. */
6301 {
6303 /* x > +Inf is always false, if with ignore sNANs. */
6309 /* x <= +Inf is always true, if we don't case about NaNs. */
6313 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6316 {
6319 }
6324 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6330 /* x < +Inf is always equal to x <= DBL_MAX. */
6336 /* x != +Inf is always equal to !(x > DBL_MAX). */
6348 }
6351 }
6353 /* Subroutine of fold() that optimizes comparisons of a division by
6354 a nonzero integer constant against an integer constant, i.e.
6355 X/C1 op C2.
6357 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6358 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6359 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6361 The function returns the constant folded tree if a simplification
6362 can be made, and NULL_TREE otherwise. */
6364 static tree
6367 {
6372 HOST_WIDE_INT hpart;
6377 /* We have to do this the hard way to detect unsigned overflow.
6378 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6389 {
6394 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6402 }
6404 {
6408 {
6427 }
6428 }
6429 else
6430 {
6431 /* A negative divisor reverses the relational operators. */
6437 {
6456 }
6457 }
6460 {
6481 {
6484 }
6489 {
6492 }
6497 {
6500 }
6505 {
6508 }
6513 }
6516 }
6519 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6520 equality/inequality test, then return a simplified form of the test
6521 using a sign testing. Otherwise return NULL. TYPE is the desired
6522 result type. */
6524 static tree
6527 tree result_type)
6528 {
6529 /* If this is testing a single bit, we can optimize the test. */
6533 {
6534 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6535 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6539 /* This is only a win if casting to a signed type is cheap,
6540 i.e. when arg00's type is not a partial mode. */
6543 {
6546 result_type,
6549 }
6550 }
6553 }
6555 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6556 equality/inequality test, then return a simplified form of
6557 the test using shifts and logical operations. Otherwise return
6558 NULL. TYPE is the desired result type. */
6560 tree
6563 {
6564 /* If this is testing a single bit, we can optimize the test. */
6568 {
6577 /* First, see if we can fold the single bit test into a sign-bit
6578 test. */
6580 result_type);
6584 /* Otherwise we have (A & C) != 0 where C is a single bit,
6585 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6586 Similarly for (A & C) == 0. */
6588 /* If INNER is a right shift of a constant and it plus BITNUM does
6589 not overflow, adjust BITNUM and INNER. */
6596 {
6599 }
6601 /* If we are going to be able to omit the AND below, we must do our
6602 operations as unsigned. If we must use the AND, we have a choice.
6603 Normally unsigned is faster, but for some machines signed is. */
6604 #ifdef LOAD_EXTEND_OP
6607 #else
6609 #endif
6625 /* Put the AND last so it can combine with more things. */
6628 /* Make sure to return the proper type. */
6632 }
6634 }
6636 /* Check whether we are allowed to reorder operands arg0 and arg1,
6637 such that the evaluation of arg1 occurs before arg0. */
6639 static bool
6641 {
6648 }
6650 /* Test whether it is preferable two swap two operands, ARG0 and
6651 ARG1, for example because ARG0 is an integer constant and ARG1
6652 isn't. If REORDER is true, only recommend swapping if we can
6653 evaluate the operands in reverse order. */
6655 bool
6657 {
6693 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6694 for commutative and comparison operators. Ensuring a canonical
6695 form allows the optimizers to find additional redundancies without
6696 having to explicitly check for both orderings. */
6702 /* Put SSA_NAMEs last. */
6708 /* Put variables last. */
6715 }
6717 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6718 ARG0 is extended to a wider type. */
6720 static tree
6723 {
6725 tree arg1_unw;
6734 #ifdef HAVE_canonicalize_funcptr_for_compare
6735 /* Disable this optimization if we're casting a function pointer
6736 type on targets that require function pointer canonicalization. */
6741 #endif
6748 /* If possible, express the comparison in the shorter mode. */
6768 /* If we are comparing with the integer that does not fit into the range
6769 of the shorter type, the result is known. */
6780 {
6807 }
6810 }
6812 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6813 ARG0 just the signedness is changed. */
6815 static tree
6818 {
6819 tree arg0_inner;
6829 #ifdef HAVE_canonicalize_funcptr_for_compare
6830 /* Disable this optimization if we're casting a function pointer
6831 type on targets that require function pointer canonicalization. */
6836 #endif
6856 else
6860 }
6862 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6863 step of the array. Reconstructs s and delta in the case of s *
6864 delta being an integer constant (and thus already folded). ADDR is
6865 the address. MULT is the multiplicative expression. If the
6866 function succeeds, the new address expression is returned.
6867 Otherwise NULL_TREE is returned. LOC is the location of the
6868 resulting expression. */
6870 static tree
6872 {
6876 tree itype;
6879 /* Strip the nops that might be added when converting op1 to sizetype. */
6882 /* Canonicalize op1 into a possibly non-constant delta
6883 and an INTEGER_CST s. */
6885 {
6892 {
6895 }
6897 {
6900 }
6901 else
6903 }
6905 {
6908 }
6909 else
6910 {
6911 /* Simulate we are delta * 1. */
6914 }
6917 {
6919 {
6920 tree domain;
6922 /* Remember if this was a multi-dimensional array. */
6936 {
6939 }
6940 else
6941 {
6942 /* Try if delta is a multiple of step. */
6947 }
6949 /* Only fold here if we can verify we do not overflow one
6950 dimension of a multi-dimensional array. */
6952 {
6953 tree tmp;
6968 }
6971 }
6972 else
6977 }
6979 /* We found the suitable array reference. So copy everything up to it,
6980 and replace the index. */
6988 {
6992 }
7000 }
7003 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7004 means A >= Y && A != MAX, but in this case we know that
7005 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7007 static tree
7009 {
7016 else
7025 {
7028 }
7030 {
7033 }
7034 else
7041 {
7042 /* Convert the pointer types into integer before taking the difference. */
7046 }
7047 else
7054 }
7056 /* Fold a sum or difference of at least one multiplication.
7057 Returns the folded tree or NULL if no simplification could be made. */
7059 static tree
7062 {
7066 /* (A * C) +- (B * C) -> (A+-B) * C.
7067 (A * C) +- A -> A * (C+-1).
7068 We are most concerned about the case where C is a constant,
7069 but other combinations show up during loop reduction. Since
7070 it is not difficult, try all four possibilities. */
7073 {
7076 }
7078 {
7081 }
7082 else
7083 {
7084 /* We cannot generate constant 1 for fract. */
7089 }
7091 {
7094 }
7096 {
7098 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7099 the purpose of this canonicalization. */
7103 {
7106 }
7107 else
7109 }
7110 else
7111 {
7112 /* We cannot generate constant 1 for fract. */
7117 }
7129 /* No identical multiplicands; see if we can find a common
7130 power-of-two factor in non-power-of-two multiplies. This
7131 can help in multi-dimensional array access. */
7134 {
7137 tree maybe_same;
7141 /* Move min of absolute values to int11. */
7144 {
7149 }
7150 else
7154 /* The remainder should not be a constant, otherwise we
7155 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7156 increased the number of multiplications necessary. */
7158 {
7166 }
7167 }
7177 }
7179 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7180 specified by EXPR into the buffer PTR of length LEN bytes.
7181 Return the number of bytes placed in the buffer, or zero
7182 upon failure. */
7184 static int
7186 {
7197 {
7201 else
7206 {
7213 else
7215 }
7216 else
7219 }
7221 }
7224 /* Subroutine of native_encode_expr. Encode the REAL_CST
7225 specified by EXPR into the buffer PTR of length LEN bytes.
7226 Return the number of bytes placed in the buffer, or zero
7227 upon failure. */
7229 static int
7231 {
7237 /* There are always 32 bits in each long, no matter the size of
7238 the hosts long. We handle floating point representations with
7239 up to 192 bits. */
7250 {
7255 {
7262 else
7264 }
7265 else
7268 }
7270 }
7272 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7273 specified by EXPR into the buffer PTR of length LEN bytes.
7274 Return the number of bytes placed in the buffer, or zero
7275 upon failure. */
7277 static int
7279 {
7281 tree part;
7292 }
7295 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7296 specified by EXPR into the buffer PTR of length LEN bytes.
7297 Return the number of bytes placed in the buffer, or zero
7298 upon failure. */
7300 static int
7302 {
7312 {
7314 {
7317 }
7318 else
7322 {
7325 }
7326 else
7327 {
7331 }
7333 }
7335 }
7338 /* Subroutine of native_encode_expr. Encode the STRING_CST
7339 specified by EXPR into the buffer PTR of length LEN bytes.
7340 Return the number of bytes placed in the buffer, or zero
7341 upon failure. */
7343 static int
7345 {
7347 HOST_WIDE_INT total_bytes;
7358 {
7362 }
7363 else
7366 }
7369 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7370 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7371 buffer PTR of length LEN bytes. Return the number of bytes
7372 placed in the buffer, or zero upon failure. */
7374 int
7376 {
7378 {
7396 }
7397 }
7400 /* Subroutine of native_interpret_expr. Interpret the contents of
7401 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7402 If the buffer cannot be interpreted, return NULL_TREE. */
7404 static tree
7406 {
7410 double_int result;
7421 {
7424 {
7431 else
7433 }
7434 else
7440 else
7443 }
7446 }
7449 /* Subroutine of native_interpret_expr. Interpret the contents of
7450 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7451 If the buffer cannot be interpreted, return NULL_TREE. */
7453 static tree
7455 {
7460 /* There are always 32 bits in each long, no matter the size of
7461 the hosts long. We handle floating point representations with
7462 up to 192 bits. */
7463 REAL_VALUE_TYPE r;
7474 {
7477 {
7484 else
7486 }
7487 else
7492 }
7496 }
7499 /* Subroutine of native_interpret_expr. Interpret the contents of
7500 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7501 If the buffer cannot be interpreted, return NULL_TREE. */
7503 static tree
7505 {
7520 }
7523 /* Subroutine of native_interpret_expr. Interpret the contents of
7524 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7525 If the buffer cannot be interpreted, return NULL_TREE. */
7527 static tree
7529 {
7541 {
7546 }
7548 }
7551 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7552 the buffer PTR of length LEN as a constant of type TYPE. For
7553 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7554 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7555 return NULL_TREE. */
7557 tree
7559 {
7561 {
7578 }
7579 }
7582 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7583 TYPE at compile-time. If we're unable to perform the conversion
7584 return NULL_TREE. */
7586 static tree
7588 {
7589 /* We support up to 512-bit values (for V8DFmode). */
7593 /* Check that the host and target are sane. */
7602 }
7604 /* Build an expression for the address of T. Folds away INDIRECT_REF
7605 to avoid confusing the gimplify process. */
7607 tree
7609 {
7610 /* The size of the object is not relevant when talking about its address. */
7614 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7617 {
7621 {
7624 }
7625 }
7627 {
7632 }
7633 else
7634 {
7637 }
7640 }
7642 /* Build an expression for the address of T. */
7644 tree
7646 {
7650 }
7652 /* Fold a unary expression of code CODE and type TYPE with operand
7653 OP0. Return the folded expression if folding is successful.
7654 Otherwise, return NULL_TREE. */
7656 tree
7658 {
7659 tree tem;
7660 tree arg0;
7668 {
7671 {
7672 /* Don't use STRIP_NOPS, because signedness of argument type
7673 matters. */
7675 }
7676 else
7677 {
7678 /* Strip any conversions that don't change the mode. This
7679 is safe for every expression, except for a comparison
7680 expression because its signedness is derived from its
7681 operands.
7683 Note that this is done as an internal manipulation within
7684 the constant folder, in order to find the simplest
7685 representation of the arguments so that their form can be
7686 studied. In any cases, the appropriate type conversions
7687 should be put back in the tree that will get out of the
7688 constant folder. */
7690 }
7691 }
7694 {
7701 {
7715 /* If this was a conversion, and all we did was to move into
7716 inside the COND_EXPR, bring it back out. But leave it if
7717 it is a conversion from integer to integer and the
7718 result precision is no wider than a word since such a
7719 conversion is cheap and may be optimized away by combine,
7720 while it couldn't if it were outside the COND_EXPR. Then return
7721 so we don't get into an infinite recursion loop taking the
7722 conversion out and then back in. */
7734 && (INTEGRAL_TYPE_P
7738 {
7747 }
7749 }
7751 {
7753 {
7757 }
7761 integer_one_node),
7763 integer_zero_node));
7764 }
7765 }
7768 {
7770 /* Re-association barriers around constants and other re-association
7771 barriers can be removed. */
7777 CASE_CONVERT:
7783 /* If we have (type) (a CMP b) and type is an integral type, return
7784 new expression involving the new type. */
7789 /* Handle cases of two conversions in a row. */
7791 {
7813 /* In addition to the cases of two conversions in a row
7814 handled below, if we are converting something to its own
7815 type via an object of identical or wider precision, neither
7816 conversion is needed. */
7823 /* Likewise, if the intermediate and initial types are either both
7824 float or both integer, we don't need the middle conversion if the
7825 former is wider than the latter and doesn't change the signedness
7826 (for integers). Avoid this if the final type is a pointer since
7827 then we sometimes need the middle conversion. Likewise if the
7828 final type has a precision not equal to the size of its mode. */
7837 && ! final_ptr
7841 /* If we have a sign-extension of a zero-extended value, we can
7842 replace that by a single zero-extension. */
7848 /* Two conversions in a row are not needed unless:
7849 - some conversion is floating-point (overstrict for now), or
7850 - some conversion is a vector (overstrict for now), or
7851 - the intermediate type is narrower than both initial and
7852 final, or
7853 - the intermediate type and innermost type differ in signedness,
7854 and the outermost type is wider than the intermediate, or
7855 - the initial type is a pointer type and the precisions of the
7856 intermediate and final types differ, or
7857 - the final type is a pointer type and the precisions of the
7858 initial and intermediate types differ. */
7872 }
7874 /* Handle (T *)&A.B.C for A being of type T and B and C
7875 living at offset zero. This occurs frequently in
7876 C++ upcasting and then accessing the base. */
7880 {
7882 tree offset;
7888 /* If the reference was to a (constant) zero offset, we can use
7889 the address of the base if it has the same base type
7890 as the result type and the pointer type is unqualified. */
7897 }
7901 /* Detect assigning a bitfield. */
7903 && DECL_BIT_FIELD
7905 {
7906 /* Don't leave an assignment inside a conversion
7907 unless assigning a bitfield. */
7909 /* First do the assignment, then return converted constant. */
7915 }
7917 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7918 constants (if x has signed type, the sign bit cannot be set
7919 in c). This folds extension into the BIT_AND_EXPR.
7920 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7921 very likely don't have maximal range for their precision and this
7922 transformation effectively doesn't preserve non-maximal ranges. */
7926 {
7937 <= HOST_BITS_PER_WIDE_INT
7939 {
7946 #ifdef LOAD_EXTEND_OP
7948 && !flag_syntax_only
7951 {
7955 }
7956 #endif
7957 }
7959 {
7965 }
7966 }
7968 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7969 when one of the new casts will fold away. Conservatively we assume
7970 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7976 {
7984 }
7986 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7987 of the same precision, and X is an integer type not narrower than
7988 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7994 {
8000 }
8002 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
8003 type of X and Y (integer types only). */
8008 {
8009 /* Be careful not to introduce new overflows. */
8010 tree mult_type;
8013 else
8017 {
8024 }
8025 }
8046 /* For integral conversions with the same precision or pointer
8047 conversions use a NOP_EXPR instead. */
8055 /* Strip inner integral conversions that do not change the precision. */
8079 /* Convert fabs((double)float) into (double)fabsf(float). */
8082 {
8088 targ0));
8089 }
8090 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8096 /* Strip sign ops from argument. */
8098 {
8103 }
8110 {
8116 }
8118 {
8123 }
8133 /* Convert ~ (-A) to A - 1. */
8138 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8147 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8162 /* Perform BIT_NOT_EXPR on each element individually. */
8164 {
8169 {
8171 {
8177 }
8178 else
8181 }
8184 }
8189 /* The argument to invert_truthvalue must have Boolean type. */
8193 /* Note that the operand of this must be an int
8194 and its values must be 0 or 1.
8195 ("true" is a fixed value perhaps depending on the language,
8196 but we don't handle values other than 1 correctly yet.) */
8211 {
8219 }
8221 {
8226 }
8228 {
8232 {
8241 }
8242 }
8254 {
8262 }
8264 {
8268 }
8270 {
8274 {
8283 }
8284 }
8288 /* Fold *&X to X if X is an lvalue. */
8290 {
8297 }
8303 }
8306 /* If the operation was a conversion do _not_ mark a resulting constant
8307 with TREE_OVERFLOW if the original constant was not. These conversions
8308 have implementation defined behavior and retaining the TREE_OVERFLOW
8309 flag here would confuse later passes such as VRP. */
8310 tree
8313 {
8322 }
8324 /* Fold a binary expression of code CODE and type TYPE with operands
8325 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8326 Return the folded expression if folding is successful. Otherwise,
8327 return NULL_TREE. */
8329 static tree
8331 {
8338 else
8341 /* MIN (MAX (a, b), b) == b. */
8346 /* MIN (MAX (b, a), b) == b. */
8352 /* MIN (a, MAX (a, b)) == a. */
8358 /* MIN (a, MAX (b, a)) == a. */
8365 }
8367 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8368 by changing CODE to reduce the magnitude of constants involved in
8369 ARG0 of the comparison.
8370 Returns a canonicalized comparison tree if a simplification was
8371 possible, otherwise returns NULL_TREE.
8372 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8373 valid if signed overflow is undefined. */
8375 static tree
8379 {
8385 /* Match A +- CST code arg1 and CST code arg1. We can change the
8386 first form only if overflow is undefined. */
8388 /* In principle pointers also have undefined overflow behavior,
8389 but that causes problems elsewhere. */
8397 /* Identify the constant in arg0 and its sign. */
8400 else
8404 /* Overflowed constants and zero will cause problems. */
8409 /* See if we can reduce the magnitude of the constant in
8410 arg0 by changing the comparison code. */
8412 {
8413 /* CST <= arg1 -> CST-1 < arg1. */
8416 /* -CST < arg1 -> -CST-1 <= arg1. */
8419 /* CST > arg1 -> CST-1 >= arg1. */
8422 /* -CST >= arg1 -> -CST-1 > arg1. */
8425 else
8427 /* arg1 code' CST' might be more canonical. */
8429 }
8430 else
8431 {
8432 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8436 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8440 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8444 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8448 else
8451 }
8453 /* Now build the constant reduced in magnitude. But not if that
8454 would produce one outside of its types range. */
8462 /* We cannot swap the comparison here as that would cause us to
8463 endlessly recurse. */
8471 /* If swapping might yield to a more canonical form, do so. */
8474 else
8476 }
8478 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8479 overflow further. Try to decrease the magnitude of constants involved
8480 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8481 and put sole constants at the second argument position.
8482 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8484 static tree
8487 {
8488 tree t;
8493 /* Try canonicalization by simplifying arg0. */
8498 {
8502 }
8504 /* Try canonicalization by simplifying arg1 using the swapped
8505 comparison. */
8513 }
8515 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8516 space. This is used to avoid issuing overflow warnings for
8517 expressions like &p->x which can not wrap. */
8519 static bool
8521 {
8532 {
8535 }
8538 else
8539 {
8542 }
8557 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8558 array. */
8560 {
8561 HOST_WIDE_INT base_size;
8566 }
8569 }
8571 /* Subroutine of fold_binary. This routine performs all of the
8572 transformations that are common to the equality/inequality
8573 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8574 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8575 fold_binary should call fold_binary. Fold a comparison with
8576 tree code CODE and type TYPE with operands OP0 and OP1. Return
8577 the folded comparison or NULL_TREE. */
8579 static tree
8582 {
8595 /* If one arg is a real or integer constant, put it last. */
8599 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8606 {
8610 tree lhs;
8617 /* If the constant operation overflowed this can be
8618 simplified as a comparison against INT_MAX/INT_MIN. */
8621 {
8625 /* Get the sign of the constant on the lhs if the
8626 operation were VARIABLE + CONST1. */
8630 /* The sign of the constant determines if we overflowed
8631 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8632 Canonicalize to the INT_MIN overflow by swapping the comparison
8633 if necessary. */
8637 /* We now can look at the canonicalized case
8638 VARIABLE + 1 CODE2 INT_MIN
8639 and decide on the result. */
8648 }
8653 {
8655 "when changing X +- C1 cmp C2 to "
8657 WARN_STRICT_OVERFLOW_COMPARISON);
8659 }
8660 }
8662 /* For comparisons of pointers we can decompose it to a compile time
8663 comparison of the base objects and the offsets into the object.
8664 This requires at least one operand being an ADDR_EXPR or a
8665 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8671 {
8678 /* Get base and offset for the access. Strip ADDR_EXPR for
8679 get_inner_reference, but put it back by stripping INDIRECT_REF
8680 off the base object if possible. indirect_baseN will be true
8681 if baseN is not an address but refers to the object itself. */
8684 {
8690 else
8692 }
8694 {
8697 }
8701 {
8707 else
8709 }
8711 {
8714 }
8716 /* A local variable can never be pointed to by
8717 the default SSA name of an incoming parameter. */
8719 && indirect_base0
8722 && !indirect_base1
8727 && indirect_base1
8730 && !indirect_base0
8734 {
8739 }
8740 /* If we have equivalent bases we might be able to simplify. */
8743 {
8744 /* We can fold this expression to a constant if the non-constant
8745 offset parts are equal. */
8753 {
8760 "occur when comparing P +- C1 with "
8762 WARN_STRICT_OVERFLOW_CONDITIONAL);
8765 {
8779 }
8780 }
8781 /* We can simplify the comparison to a comparison of the variable
8782 offset parts if the constant offset parts are equal.
8783 Be careful to use signed size type here because otherwise we
8784 mess with array offsets in the wrong way. This is possible
8785 because pointer arithmetic is restricted to retain within an
8786 object and overflow on pointer differences is undefined as of
8787 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8791 {
8792 /* By converting to signed size type we cover middle-end pointer
8793 arithmetic which operates on unsigned pointer types of size
8794 type size and ARRAY_REF offsets which are properly sign or
8795 zero extended from their type in case it is narrower than
8796 size type. */
8799 else
8803 else
8811 "occur when comparing P +- C1 with "
8813 WARN_STRICT_OVERFLOW_COMPARISON);
8816 }
8817 }
8818 /* For non-equal bases we can simplify if they are addresses
8819 of local binding decls or constants. */
8821 /* We know that !operand_equal_p (base0, base1, 0)
8822 because the if condition was false. But make
8823 sure two decls are not the same. */
8837 {
8844 }
8845 /* For equal offsets we can simplify to a comparison of the
8846 base addresses. */
8848 && (indirect_base0
8850 && (indirect_base1
8855 {
8861 }
8862 }
8864 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8865 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8866 the resulting offset is smaller in absolute value than the
8867 original one. */
8875 {
8880 tree cst;
8882 "occur when combining constants around "
8885 /* Put the constant on the side where it doesn't overflow and is
8886 of lower absolute value than before. */
8892 {
8895 variable1,
8899 }
8906 {
8911 variable2);
8912 }
8913 }
8915 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8916 signed arithmetic case. That form is created by the compiler
8917 often enough for folding it to be of value. One example is in
8918 computing loop trip counts after Operator Strength Reduction. */
8924 {
8930 /* Handle unfolded multiplication by zero. */
8935 "eliminating multiplication in comparison "
8937 WARN_STRICT_OVERFLOW_COMPARISON);
8939 /* If const1 is negative we swap the sense of the comparison. */
8944 }
8951 {
8959 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8965 /* (-a) CMP (-b) -> b CMP a */
8972 {
8973 REAL_VALUE_TYPE cst;
8976 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8983 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8984 /* a CMP (-0) -> a CMP 0 */
8989 /* x != NaN is always true, other ops are always false. */
8992 {
8995 }
8997 /* Fold comparisons against infinity. */
9000 {
9004 }
9005 }
9007 /* If this is a comparison of a real constant with a PLUS_EXPR
9008 or a MINUS_EXPR of a real constant, we can convert it into a
9009 comparison with a revised real constant as long as no overflow
9010 occurs when unsafe_math_optimizations are enabled. */
9022 /* Likewise, we can simplify a comparison of a real constant with
9023 a MINUS_EXPR whose first operand is also a real constant, i.e.
9024 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9025 floating-point types only if -fassociative-math is set. */
9036 /* Fold comparisons against built-in math functions. */
9038 && flag_unsafe_math_optimizations
9040 {
9044 {
9048 }
9049 }
9050 }
9054 {
9055 /* If we are widening one operand of an integer comparison,
9056 see if the other operand is similarly being widened. Perhaps we
9057 can do the comparison in the narrower type. */
9062 /* Or if we are changing signedness. */
9066 }
9068 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9069 constant, we can simplify it. */
9074 {
9078 }
9080 /* Simplify comparison of something with itself. (For IEEE
9081 floating-point, we can only do some of these simplifications.) */
9083 {
9085 {
9100 /* For NE, we can only do this simplification if integer
9101 or we don't honor IEEE floating point NaNs. */
9105 /* ... fall through ... */
9111 }
9112 }
9114 /* If we are comparing an expression that just has comparisons
9115 of two integer values, arithmetic expressions of those comparisons,
9116 and constants, we can simplify it. There are only three cases
9117 to check: the two values can either be equal, the first can be
9118 greater, or the second can be greater. Fold the expression for
9119 those three values. Since each value must be 0 or 1, we have
9120 eight possibilities, each of which corresponds to the constant 0
9121 or 1 or one of the six possible comparisons.
9123 This handles common cases like (a > b) == 0 but also handles
9124 expressions like ((x > y) - (y > x)) > 0, which supposedly
9125 occur in macroized code. */
9128 {
9133 /* Don't handle degenerate cases here; they should already
9134 have been handled anyway. */
9143 {
9147 /* We can't just pass T to eval_subst in case cval1 or cval2
9148 was the same as ARG1. */
9150 tree high_result
9154 arg1);
9155 tree equal_result
9159 arg1);
9160 tree low_result
9164 arg1);
9166 /* All three of these results should be 0 or 1. Confirm they are.
9167 Then use those values to select the proper code to use. */
9172 {
9173 /* Make a 3-bit mask with the high-order bit being the
9174 value for `>', the next for '=', and the low for '<'. */
9178 {
9180 /* Always false. */
9201 /* Always true. */
9203 }
9206 {
9210 }
9212 }
9213 }
9214 }
9216 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9217 into a single range test. */
9225 {
9229 }
9231 /* Fold ~X op ~Y as Y op X. */
9234 {
9240 }
9242 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9245 {
9251 }
9254 }
9257 /* Subroutine of fold_binary. Optimize complex multiplications of the
9258 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9259 argument EXPR represents the expression "z" of type TYPE. */
9261 static tree
9263 {
9268 {
9271 }
9273 {
9276 }
9277 else
9278 {
9282 }
9291 }
9294 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9295 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9296 guarantees that P and N have the same least significant log2(M) bits.
9297 N is not otherwise constrained. In particular, N is not normalized to
9298 0 <= N < M as is common. In general, the precise value of P is unknown.
9299 M is chosen as large as possible such that constant N can be determined.
9301 Returns M and sets *RESIDUE to N.
9303 If ALLOW_FUNC_ALIGN is true, do take functions' DECL_ALIGN_UNIT into
9304 account. This is not always possible due to PR 35705.
9305 */
9307 static unsigned HOST_WIDE_INT
9310 {
9317 {
9320 {
9322 tree offset;
9330 {
9333 else
9334 /* We don't handle more complicated offset expressions. */
9336 }
9337 }
9342 }
9344 {
9352 allow_func_align);
9358 {
9361 }
9363 {
9366 {
9369 /* Compute the greatest power-of-2 divisor of op1. */
9373 /* If align is non-zero and less than *modulus, replace
9374 *modulus with align., If align is 0, then either op1 is 0
9375 or the greatest power-of-2 divisor of op1 doesn't fit in an
9376 unsigned HOST_WIDE_INT. In either case, no additional
9377 constraint is imposed. */
9382 }
9383 }
9384 }
9386 /* If we get here, we were unable to determine anything useful about the
9387 expression. */
9389 }
9392 /* Fold a binary expression of code CODE and type TYPE with operands
9393 OP0 and OP1. LOC is the location of the resulting expression.
9394 Return the folded expression if folding is successful. Otherwise,
9395 return NULL_TREE. */
9397 tree
9400 {
9414 /* Strip any conversions that don't change the mode. This is
9415 safe for every expression, except for a comparison expression
9416 because its signedness is derived from its operands. So, in
9417 the latter case, only strip conversions that don't change the
9418 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9419 preserved.
9421 Note that this is done as an internal manipulation within the
9422 constant folder, in order to find the simplest representation
9423 of the arguments so that their form can be studied. In any
9424 cases, the appropriate type conversions should be put back in
9425 the tree that will get out of the constant folder. */
9428 {
9431 }
9432 else
9433 {
9436 }
9438 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9439 constant but we can't do arithmetic on them. */
9446 {
9448 {
9449 /* Make sure type and arg0 have the same saturating flag. */
9453 }
9456 else
9460 {
9464 }
9465 }
9467 /* If this is a commutative operation, and ARG0 is a constant, move it
9468 to ARG1 to reduce the number of tests below. */
9473 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9475 First check for cases where an arithmetic operation is applied to a
9476 compound, conditional, or comparison operation. Push the arithmetic
9477 operation inside the compound or conditional to see if any folding
9478 can then be done. Convert comparison to conditional for this purpose.
9479 The also optimizes non-constant cases that used to be done in
9480 expand_expr.
9482 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9483 one of the operands is a comparison and the other is a comparison, a
9484 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9485 code below would make the expression more complex. Change it to a
9486 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9487 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9499 {
9503 boolean_type_node,
9511 }
9515 {
9517 {
9523 }
9526 {
9532 }
9535 {
9541 }
9544 {
9550 }
9551 }
9554 {
9556 /* 0 +p index -> (type)index */
9560 /* PTR +p 0 -> PTR */
9564 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9570 arg1),
9572 arg0)));
9574 /* index +p PTR -> PTR +p index */
9581 /* (PTR +p B) +p A -> PTR +p (B + A) */
9583 {
9584 tree inner;
9593 }
9595 /* PTR_CST +p CST -> CST1 */
9600 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9601 of the array. Loop optimizer sometimes produce this type of
9602 expressions. */
9604 {
9609 }
9614 /* A + (-B) -> A - B */
9620 /* (-A) + B -> B - A */
9629 {
9630 /* Convert ~A + 1 to -A. */
9637 /* ~X + X is -1. */
9640 {
9645 {
9648 }
9649 }
9651 /* X + ~X is -1. */
9654 {
9659 {
9662 }
9663 }
9665 /* X + (X / CST) * -CST is X % CST. */
9670 {
9679 cst0));
9680 }
9681 }
9683 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9684 same or one. Make sure type is not saturating.
9685 fold_plusminus_mult_expr will re-associate. */
9690 {
9694 }
9697 {
9701 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9702 with a constant, and the two constants have no bits in common,
9703 we should treat this as a BIT_IOR_EXPR since this may produce more
9704 simplifications. */
9712 {
9715 }
9717 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9718 (plus (plus (mult) (mult)) (foo)) so that we can
9719 take advantage of the factoring cases below. */
9726 {
9732 else
9745 parg0),
9747 marg)),
9751 return
9757 parg1)));
9758 }
9759 }
9760 else
9761 {
9762 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9766 /* Likewise if the operands are reversed. */
9770 /* Convert X + -C into X - C. */
9773 {
9779 }
9781 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9782 to __complex__ ( x, y ). This is not the same for SNaNs or
9783 if signed zeros are involved. */
9787 {
9794 {
9798 {
9804 }
9806 {
9812 }
9813 }
9814 }
9822 /* Convert x+x into x*2.0. */
9828 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9829 We associate floats only if the user has specified
9830 -fassociative-math. */
9834 {
9839 {
9840 tree tree0;
9843 }
9844 }
9845 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9846 We associate floats only if the user has specified
9847 -fassociative-math. */
9851 {
9856 {
9857 tree tree0;
9860 }
9861 }
9862 }
9864 bit_rotate:
9865 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9866 is a rotate of A by C1 bits. */
9867 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9868 is a rotate of A by B bits. */
9869 {
9871 tree rtype;
9880 /* Only create rotates in complete modes. Other cases are not
9881 expanded properly. */
9883 {
9899 {
9903 code0 == LSHIFT_EXPR
9907 }
9909 {
9917 TYPE_PRECISION
9921 return
9924 ? LROTATE_EXPR
9928 }
9930 {
9938 TYPE_PRECISION
9942 return fold_convert_loc
9945 ? LROTATE_EXPR
9949 }
9950 }
9951 }
9953 associate:
9954 /* In most languages, can't associate operations on floats through
9955 parentheses. Rather than remember where the parentheses were, we
9956 don't associate floats at all, unless the user has specified
9957 -fassociative-math.
9958 And, we need to make sure type is not saturating. */
9962 {
9967 /* Split both trees into variables, constants, and literals. Then
9968 associate each group together, the constants with literals,
9969 then the result with variables. This increases the chances of
9970 literals being recombined later and of generating relocatable
9971 expressions for the sum of a constant and literal. */
9976 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9980 /* With undefined overflow we can only associate constants with one
9981 variable, and constants whose association doesn't overflow. */
9984 {
9986 {
9994 /* The only case we can still associate with two variables
9995 is if they are the same, modulo negation. */
9998 }
10001 {
10008 }
10009 }
10011 /* Only do something if we found more than two objects. Otherwise,
10012 nothing has changed and we risk infinite recursion. */
10018 {
10024 /* Preserve the MINUS_EXPR if the negative part of the literal is
10025 greater than the positive part. Otherwise, the multiplicative
10026 folding code (i.e extract_muldiv) may be fooled in case
10027 unsigned constants are subtracted, like in the following
10028 example: ((X*2 + 4) - 8U)/2. */
10030 {
10034 {
10038 }
10039 else
10040 {
10044 }
10045 }
10047 {
10049 return
10053 else
10054 {
10057 return
10061 }
10062 }
10065 return
10068 }
10069 }
10074 /* Pointer simplifications for subtraction, simple reassociations. */
10076 {
10077 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10080 {
10090 }
10091 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10093 {
10100 }
10101 }
10102 /* A - (-B) -> A + B */
10107 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10118 /* Convert -A - 1 to ~A. */
10127 /* Convert -1 - A to ~A. */
10133 /* X - (X / CST) * CST is X % CST. */
10141 return
10147 {
10153 /* Fold A - (A & B) into ~B & A. */
10156 {
10158 {
10165 }
10167 {
10174 }
10175 }
10177 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10178 any power of 2 minus 1. */
10183 {
10189 {
10193 }
10194 }
10195 }
10197 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10201 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10202 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10203 (-ARG1 + ARG0) reduces to -ARG1. */
10207 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10208 __complex__ ( x, -y ). This is not the same for SNaNs or if
10209 signed zeros are involved. */
10213 {
10220 {
10224 {
10226 arg1r ? arg1r
10231 }
10233 {
10237 arg1i ? arg1i
10240 }
10241 }
10242 }
10244 /* Fold &x - &x. This can happen from &x.foo - &x.
10245 This is unsafe for certain floats even in non-IEEE formats.
10246 In IEEE, it is unsafe because it does wrong for NaNs.
10247 Also note that operand_equal_p is always false if an operand
10248 is volatile. */
10254 /* A - B -> A + (-B) if B is easily negatable. */
10257 /* Avoid this transformation if B is a positive REAL_CST. */
10266 /* Try folding difference of addresses. */
10267 {
10268 HOST_WIDE_INT diff;
10274 }
10276 /* Fold &a[i] - &a[j] to i-j. */
10281 {
10286 {
10294 }
10295 }
10298 && flag_unsafe_math_optimizations
10304 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10305 same or one. Make sure type is not saturating.
10306 fold_plusminus_mult_expr will re-associate. */
10311 {
10315 }
10320 /* (-A) * (-B) -> A * B */
10335 {
10340 /* Transform x * -1 into -x. Make sure to do the negation
10341 on the original operand with conversions not stripped
10342 because we can only strip non-sign-changing conversions. */
10345 /* Transform x * -C into -x * C if x is easily negatable. */
10354 tem);
10356 /* (a * (1 << b)) is (a << b) */
10366 /* (A + A) * C -> A * 2 * C */
10382 {
10385 "occur when simplifying "
10387 WARN_STRICT_OVERFLOW_MISC);
10389 }
10391 /* Optimize z * conj(z) for integer complex numbers. */
10398 }
10399 else
10400 {
10401 /* Maybe fold x * 0 to 0. The expressions aren't the same
10402 when x is NaN, since x * 0 is also NaN. Nor are they the
10403 same in modes with signed zeros, since multiplying a
10404 negative value by 0 gives -0, not +0. */
10409 /* In IEEE floating point, x*1 is not equivalent to x for snans.
10410 Likewise for complex arithmetic with signed zeros. */
10417 /* Transform x * -1.0 into -x. */
10424 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10425 the result for floating point types due to rounding so it is applied
10426 only if -fassociative-math was specify. */
10431 {
10437 }
10439 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10441 {
10444 {
10447 }
10448 }
10450 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10451 This is not the same for NaNs or if signed zeros are
10452 involved. */
10458 {
10461 return
10467 return
10472 }
10474 /* Optimize z * conj(z) for floating point complex numbers.
10475 Guarded by flag_unsafe_math_optimizations as non-finite
10476 imaginary components don't produce scalar results. */
10487 {
10491 /* Optimizations of root(...)*root(...). */
10493 {
10498 /* Optimize sqrt(x)*sqrt(x) as x. */
10504 /* Optimize root(x)*root(y) as root(x*y). */
10508 }
10510 /* Optimize expN(x)*expN(y) as expN(x+y). */
10512 {
10518 }
10520 /* Optimizations of pow(...)*pow(...). */
10524 {
10530 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10532 {
10537 }
10539 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10541 {
10546 }
10547 }
10549 /* Optimize tan(x)*cos(x) as sin(x). */
10558 {
10564 }
10566 /* Optimize x*pow(x,c) as pow(x,c+1). */
10570 {
10576 {
10578 REAL_VALUE_TYPE c;
10579 tree arg;
10585 }
10586 }
10588 /* Optimize pow(x,c)*x as pow(x,c+1). */
10592 {
10598 {
10600 REAL_VALUE_TYPE c;
10601 tree arg;
10607 }
10608 }
10610 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10613 {
10617 {
10620 }
10621 }
10622 }
10623 }
10627 bit_ior:
10635 /* ~X | X is -1. */
10638 {
10642 }
10644 /* X | ~X is -1. */
10647 {
10651 }
10653 /* Canonicalize (X & C1) | C2. */
10657 {
10665 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10671 {
10675 }
10676 else
10677 {
10681 }
10683 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10688 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10689 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10690 mode which allows further optimizations. */
10700 {
10701 unsigned HOST_WIDE_INT mask
10705 {
10709 }
10710 }
10717 arg1);
10718 }
10720 /* (X & Y) | Y is (X, Y). */
10724 /* (X & Y) | X is (Y, X). */
10729 /* X | (X & Y) is (Y, X). */
10734 /* X | (Y & X) is (Y, X). */
10744 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10746 This results in more efficient code for machines without a NAND
10747 instruction. Combine will canonicalize to the first form
10748 which will allow use of NAND instructions provided by the
10749 backend if they exist. */
10752 {
10753 return
10760 }
10762 /* See if this can be simplified into a rotate first. If that
10763 is unsuccessful continue in the association code. */
10774 /* ~X ^ X is -1. */
10777 {
10781 }
10783 /* X ^ ~X is -1. */
10786 {
10790 }
10792 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10793 with a constant, and the two constants have no bits in common,
10794 we should treat this as a BIT_IOR_EXPR since this may produce more
10795 simplifications. */
10803 {
10806 }
10808 /* (X | Y) ^ X -> Y & ~ X*/
10811 {
10814 arg1);
10819 }
10821 /* (Y | X) ^ X -> Y & ~ X*/
10824 {
10827 arg1);
10832 }
10834 /* X ^ (X | Y) -> Y & ~ X*/
10837 {
10840 arg0);
10845 }
10847 /* X ^ (Y | X) -> Y & ~ X*/
10850 {
10853 arg0);
10858 }
10860 /* Convert ~X ^ ~Y to X ^ Y. */
10869 /* Convert ~X ^ C to X ^ ~C. */
10877 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10884 /* Fold (X & Y) ^ Y as ~X & Y. */
10887 {
10892 }
10893 /* Fold (X & Y) ^ X as ~Y & X. */
10897 {
10902 }
10903 /* Fold X ^ (X & Y) as X & ~Y. */
10906 {
10911 }
10912 /* Fold X ^ (Y & X) as ~Y & X. */
10916 {
10921 }
10923 /* See if this can be simplified into a rotate first. If that
10924 is unsuccessful continue in the association code. */
10935 /* ~X & X is always zero. */
10940 /* X & ~X is always zero. */
10945 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10949 {
10955 return
10959 }
10961 /* (X | Y) & Y is (X, Y). */
10965 /* (X | Y) & X is (Y, X). */
10970 /* X & (X | Y) is (Y, X). */
10975 /* X & (Y | X) is (Y, X). */
10981 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10985 {
10991 }
10992 /* Fold ~X & 1 as (X & 1) == 0. */
10995 {
11001 }
11003 /* Fold (X ^ Y) & Y as ~X & Y. */
11006 {
11011 }
11012 /* Fold (X ^ Y) & X as ~Y & X. */
11016 {
11021 }
11022 /* Fold X & (X ^ Y) as X & ~Y. */
11025 {
11030 }
11031 /* Fold X & (Y ^ X) as ~Y & X. */
11035 {
11040 }
11045 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11048 {
11049 unsigned int prec
11055 return
11057 }
11059 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
11061 This results in more efficient code for machines without a NOR
11062 instruction. Combine will canonicalize to the first form
11063 which will allow use of NOR instructions provided by the
11064 backend if they exist. */
11067 {
11074 }
11076 /* If arg0 is derived from the address of an object or function, we may
11077 be able to fold this expression using the object or function's
11078 alignment. */
11080 {
11087 /* This works because modulus is a power of 2. If this weren't the
11088 case, we'd have to replace it by its greatest power-of-2
11089 divisor: modulus & -modulus. */
11092 }
11094 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
11095 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
11096 if the new mask might be further optimized. */
11105 {
11107 unsigned HOST_WIDE_INT mask
11117 {
11120 /* See if more bits can be proven as zero because of
11121 zero extension. */
11124 {
11129 {
11131 /* See if we can shorten the right shift. */
11134 }
11135 }
11139 /* For arithmetic shift if sign bit could be set, zerobits
11140 can contain actually sign bits, so no transformation is
11141 possible, unless MASK masks them all away. In that
11142 case the shift needs to be converted into logical shift. */
11145 {
11148 else
11150 }
11151 }
11153 /* ((X << 16) & 0xff00) is (X, 0). */
11160 {
11163 /* Only do the transformation if NEWMASK is some integer
11164 mode's mask. */
11171 {
11172 tree newmaskt;
11175 {
11181 }
11182 else
11187 }
11188 }
11189 }
11194 /* Don't touch a floating-point divide by zero unless the mode
11195 of the constant can represent infinity. */
11201 /* Optimize A / A to 1.0 if we don't care about
11202 NaNs or Infinities. Skip the transformation
11203 for non-real operands. */
11208 {
11212 }
11214 /* The complex version of the above A / A optimization. */
11217 {
11221 {
11223 /* omit_two_operands will call fold_convert for us. */
11225 }
11226 }
11228 /* (-A) / (-B) -> A / B */
11238 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11243 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11249 /* If ARG1 is a constant, we can convert this to a multiply by the
11250 reciprocal. This does not have the same rounding properties,
11251 so only do this if -freciprocal-math. We can actually
11252 always safely do it if ARG1 is a power of two, but it's hard to
11253 tell if it is or not in a portable manner. */
11255 {
11260 /* Find the reciprocal if optimizing and the result is exact. */
11262 {
11263 REAL_VALUE_TYPE r;
11266 {
11270 }
11271 }
11272 }
11273 /* Convert A/B/C to A/(B*C). */
11280 /* Convert A/(B/C) to (A/B)*C. */
11288 /* Convert C1/(X*C2) into (C1/C2)/X. */
11293 {
11299 }
11302 {
11306 /* Optimize sin(x)/cos(x) as tan(x). */
11312 {
11317 }
11319 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11325 {
11329 {
11334 }
11335 }
11337 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11338 NaNs or Infinities. */
11342 {
11349 {
11354 }
11355 }
11357 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11358 NaNs or Infinities. */
11362 {
11369 {
11373 {
11377 tmp);
11378 }
11379 }
11380 }
11382 /* Optimize pow(x,c)/x as pow(x,c-1). */
11386 {
11392 {
11394 REAL_VALUE_TYPE c;
11395 tree arg;
11401 }
11402 }
11404 /* Optimize a/root(b/c) into a*root(c/b). */
11406 {
11410 {
11419 }
11420 }
11422 /* Optimize x/expN(y) into x*expN(-y). */
11424 {
11431 }
11433 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11437 {
11445 }
11446 }
11451 /* Simplify A / (B << N) where A and B are positive and B is
11452 a power of 2, to A >> (N + log2(B)). */
11457 {
11460 {
11467 WARN_STRICT_OVERFLOW_MISC);
11473 }
11474 }
11476 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11477 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11483 /* Fall thru */
11492 /* X / -1 is -X. */
11499 /* Convert -A / -B to A / B when the type is signed and overflow is
11500 undefined. */
11504 {
11507 "when distributing negation across "
11509 WARN_STRICT_OVERFLOW_MISC);
11515 }
11519 {
11522 "when distributing negation across "
11524 WARN_STRICT_OVERFLOW_MISC);
11530 }
11532 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11533 operation, EXACT_DIV_EXPR.
11535 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11536 At one time others generated faster code, it's not clear if they do
11537 after the last round to changes to the DIV code in expmed.c. */
11546 {
11550 WARN_STRICT_OVERFLOW_MISC);
11552 }
11560 /* X % 1 is always zero, but be sure to preserve any side
11561 effects in X. */
11565 /* X % 0, return X % 0 unchanged so that we can get the
11566 proper warnings and errors. */
11570 /* 0 % X is always zero, but be sure to preserve any side
11571 effects in X. Place this after checking for X == 0. */
11575 /* X % -1 is zero. */
11582 /* X % -C is the same as X % C. */
11589 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11596 /* X % -Y is the same as X % Y. */
11609 {
11613 WARN_STRICT_OVERFLOW_MISC);
11615 }
11617 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11618 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11622 {
11624 /* Also optimize A % (C << N) where C is a power of 2,
11625 to A & ((C << N) - 1). */
11630 {
11631 tree mask
11636 "occur when simplifying "
11638 WARN_STRICT_OVERFLOW_MISC);
11642 }
11643 }
11654 /* Optimize -1 >> x for arithmetic right shifts. */
11658 /* ... fall through ... */
11661 shift:
11667 /* Since negative shift count is not well-defined,
11668 don't try to compute it in the compiler. */
11672 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11677 {
11681 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11682 being well defined. */
11684 {
11690 else
11692 }
11696 }
11698 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11699 into x & ((unsigned)-1 >> c) for unsigned types. */
11707 {
11710 tree lshift;
11711 tree arg00;
11714 {
11721 }
11722 }
11724 /* Rewrite an LROTATE_EXPR by a constant into an
11725 RROTATE_EXPR by a new constant. */
11727 {
11732 }
11734 /* If we have a rotate of a bit operation with the rotate count and
11735 the second operand of the bit operation both constant,
11736 permute the two operations. */
11748 /* Two consecutive rotates adding up to the precision of the
11749 type can be ignored. */
11760 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11761 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11762 if the latter can be further optimized. */
11767 {
11771 arg1);
11775 arg1);
11779 }
11807 /* Note that the operands of this must be ints
11808 and their values must be 0 or 1.
11809 ("true" is a fixed value perhaps depending on the language.) */
11810 /* If first arg is constant zero, return it. */
11814 /* If either arg is constant true, drop it. */
11818 /* Preserve sequence points. */
11821 /* If second arg is constant zero, result is zero, but first arg
11822 must be evaluated. */
11825 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11826 case will be handled here. */
11830 /* !X && X is always false. */
11834 /* X && !X is always false. */
11839 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11840 means A >= Y && A != MAX, but in this case we know that
11841 A < X <= MAX. */
11845 {
11853 }
11855 truth_andor:
11856 /* We only do these simplifications if we are optimizing. */
11860 /* Check for things like (A || B) && (A || C). We can convert this
11861 to A || (B && C). Note that either operator can be any of the four
11862 truth and/or operations and the transformation will still be
11863 valid. Also note that we only care about order for the
11864 ANDIF and ORIF operators. If B contains side effects, this
11865 might change the truth-value of A. */
11872 {
11892 /* This case if tricky because we must either have commutative
11893 operators or else A10 must not have side-effects. */
11899 a01);
11900 }
11902 /* See if we can build a range comparison. */
11908 {
11912 }
11916 {
11920 }
11922 /* Check for the possibility of merging component references. If our
11923 lhs is another similar operation, try to merge its rhs with our
11924 rhs. Then try to merge our lhs and rhs. */
11936 /* Note that the operands of this must be ints
11937 and their values must be 0 or true.
11938 ("true" is a fixed value perhaps depending on the language.) */
11939 /* If first arg is constant true, return it. */
11943 /* If either arg is constant zero, drop it. */
11947 /* Preserve sequence points. */
11950 /* If second arg is constant true, result is true, but we must
11951 evaluate first arg. */
11954 /* Likewise for first arg, but note this only occurs here for
11955 TRUTH_OR_EXPR. */
11959 /* !X || X is always true. */
11963 /* X || !X is always true. */
11971 /* If the second arg is constant zero, drop it. */
11974 /* If the second arg is constant true, this is a logical inversion. */
11976 {
11977 /* Only call invert_truthvalue if operand is a truth value. */
11980 else
11983 }
11984 /* Identical arguments cancel to zero. */
11988 /* !X ^ X is always true. */
11993 /* X ^ !X is always true. */
12006 /* bool_var != 0 becomes bool_var. */
12011 /* bool_var == 1 becomes bool_var. */
12016 /* bool_var != 1 becomes !bool_var. */
12022 /* bool_var == 0 becomes !bool_var. */
12028 /* !exp != 0 becomes !exp */
12033 /* If this is an equality comparison of the address of two non-weak,
12034 unaliased symbols neither of which are extern (since we do not
12035 have access to attributes for externs), then we know the result. */
12048 {
12049 /* We know that we're looking at the address of two
12050 non-weak, unaliased, static _DECL nodes.
12052 It is both wasteful and incorrect to call operand_equal_p
12053 to compare the two ADDR_EXPR nodes. It is wasteful in that
12054 all we need to do is test pointer equality for the arguments
12055 to the two ADDR_EXPR nodes. It is incorrect to use
12056 operand_equal_p as that function is NOT equivalent to a
12057 C equality test. It can in fact return false for two
12058 objects which would test as equal using the C equality
12059 operator. */
12063 type);
12064 }
12066 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
12067 a MINUS_EXPR of a constant, we can convert it into a comparison with
12068 a revised constant as long as no overflow occurs. */
12076 arg1),
12081 /* Similarly for a NEGATE_EXPR. */
12089 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
12097 arg1),
12100 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
12107 {
12111 val,
12115 }
12117 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
12122 {
12124 code == NE_EXPR
12127 }
12129 /* If we have X - Y == 0, we can convert that to X == Y and similarly
12130 for !=. Don't do this for ordered comparisons due to overflow. */
12136 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
12141 /* If this is an EQ or NE comparison with zero and ARG0 is
12142 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12143 two operations, but the latter can be done in one less insn
12144 on machines that have only two-operand insns or on which a
12145 constant cannot be the first operand. */
12148 {
12153 {
12160 arg1);
12161 }
12164 {
12171 arg1);
12172 }
12173 }
12175 /* If this is an NE or EQ comparison of zero against the result of a
12176 signed MOD operation whose second operand is a power of 2, make
12177 the MOD operation unsigned since it is simpler and equivalent. */
12185 {
12195 }
12197 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12198 C1 is a valid shift constant, and C2 is a power of two, i.e.
12199 a single bit. */
12203 == INTEGER_CST
12206 {
12211 /* Check for a valid shift count. */
12214 {
12218 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12219 can be rewritten as (X & (C2 << C1)) != 0. */
12221 {
12225 }
12226 /* Otherwise, for signed (arithmetic) shifts,
12227 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12228 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12232 /* Otherwise, of unsigned (logical) shifts,
12233 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12234 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12235 else
12239 arg000);
12240 }
12241 }
12243 /* If this is an NE comparison of zero with an AND of one, remove the
12244 comparison since the AND will give the correct value. */
12251 /* If we have (A & C) == C where C is a power of 2, convert this into
12252 (A & C) != 0. Similarly for NE_EXPR. */
12258 integer_zero_node));
12260 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12261 bit, then fold the expression into A < 0 or A >= 0. */
12266 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12267 Similarly for NE_EXPR. */
12271 {
12280 }
12282 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12283 Similarly for NE_EXPR. */
12287 {
12294 }
12296 /* If this is a comparison of a field, we may be able to simplify it. */
12299 /* Handle the constant case even without -O
12300 to make sure the warnings are given. */
12302 {
12306 }
12308 /* Optimize comparisons of strlen vs zero to a compare of the
12309 first character of the string vs zero. To wit,
12310 strlen(ptr) == 0 => *ptr == 0
12311 strlen(ptr) != 0 => *ptr != 0
12312 Other cases should reduce to one of these two (or a constant)
12313 due to the return value of strlen being unsigned. */
12316 {
12324 {
12329 }
12330 }
12332 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12333 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12337 {
12344 {
12346 {
12349 }
12352 }
12353 }
12355 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12361 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12366 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12373 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12381 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12382 (X & C) == 0 when C is a single bit. */
12387 {
12393 }
12395 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12396 constant C is a power of two, i.e. a single bit. */
12403 {
12407 }
12409 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12410 when is C is a power of two, i.e. a single bit. */
12417 {
12423 }
12427 {
12430 }
12432 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12439 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12442 {
12455 arg01),
12464 arg01),
12473 arg00),
12482 arg00),
12484 }
12488 {
12495 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12496 operand_equal_p guarantees no side-effects so we don't need
12497 to use omit_one_operand on Z. */
12507 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12515 arg10);
12516 }
12518 /* Attempt to simplify equality/inequality comparisons of complex
12519 values. Only lower the comparison if the result is known or
12520 can be simplified to a single scalar comparison. */
12525 {
12530 {
12533 }
12534 else
12535 {
12538 }
12541 {
12544 }
12545 else
12546 {
12549 }
12553 {
12555 {
12560 }
12561 else
12562 {
12567 }
12568 }
12572 {
12574 {
12579 }
12580 else
12581 {
12586 }
12587 }
12588 }
12600 /* Transform comparisons of the form X +- C CMP X. */
12607 {
12614 else
12617 /* (X - c) > X becomes false. */
12621 {
12625 "occur when assuming that (X - c) > X "
12627 WARN_STRICT_OVERFLOW_ALL);
12629 }
12631 /* Likewise (X + c) < X becomes false. */
12635 {
12639 "occur when assuming that "
12641 WARN_STRICT_OVERFLOW_ALL);
12643 }
12645 /* Convert (X - c) <= X to true. */
12650 {
12654 "occur when assuming that "
12656 WARN_STRICT_OVERFLOW_ALL);
12658 }
12660 /* Convert (X + c) >= X to true. */
12665 {
12669 "occur when assuming that "
12671 WARN_STRICT_OVERFLOW_ALL);
12673 }
12676 {
12677 /* Convert X + c > X and X - c < X to true for integers. */
12681 {
12684 "not occur when assuming that "
12686 WARN_STRICT_OVERFLOW_ALL);
12688 }
12693 {
12696 "not occur when assuming that "
12698 WARN_STRICT_OVERFLOW_ALL);
12700 }
12702 /* Convert X + c <= X and X - c >= X to false for integers. */
12706 {
12709 "not occur when assuming that "
12711 WARN_STRICT_OVERFLOW_ALL);
12713 }
12718 {
12721 "not occur when assuming that "
12723 WARN_STRICT_OVERFLOW_ALL);
12725 }
12726 }
12727 }
12729 /* Comparisons with the highest or lowest possible integer of
12730 the specified precision will have known values. */
12731 {
12738 {
12739 HOST_WIDE_INT signed_max_hi;
12744 {
12751 {
12755 }
12756 else
12757 {
12761 }
12762 }
12763 else
12764 {
12773 {
12776 }
12777 else
12778 {
12781 }
12782 }
12787 {
12800 /* The GE_EXPR and LT_EXPR cases above are not normally
12801 reached because of previous transformations. */
12805 }
12807 == max_hi
12810 {
12817 arg1);
12823 arg0),
12824 arg1);
12827 }
12829 == min_hi
12832 {
12847 }
12849 == min_hi
12852 {
12858 arg1);
12863 arg0),
12864 arg1);
12867 }
12872 /* We will flip the signedness of the comparison operator
12873 associated with the mode of arg1, so the sign bit is
12874 specified by this mode. Check that arg1 is the signed
12875 max associated with this sign bit. */
12877 /* signed_type does not work on pointer types. */
12879 {
12880 /* The following case also applies to X < signed_max+1
12881 and X >= signed_max+1 because previous transformations. */
12883 {
12884 tree st;
12890 }
12891 }
12892 }
12893 }
12895 /* If we are comparing an ABS_EXPR with a constant, we can
12896 convert all the cases into explicit comparisons, but they may
12897 well not be faster than doing the ABS and one comparison.
12898 But ABS (X) <= C is a range comparison, which becomes a subtraction
12899 and a comparison, and is probably faster. */
12913 /* Convert ABS_EXPR<x> >= 0 to true. */
12920 {
12923 "when simplifying comparison of "
12925 WARN_STRICT_OVERFLOW_CONDITIONAL);
12927 }
12929 /* Convert ABS_EXPR<x> < 0 to false. */
12934 {
12937 "when simplifying comparison of "
12939 WARN_STRICT_OVERFLOW_CONDITIONAL);
12941 }
12943 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12944 and similarly for >= into !=. */
12949 {
12955 }
12962 {
12971 }
12984 {
12988 }
12990 /* If the first operand is NaN, the result is constant. */
12994 {
12996 ? integer_zero_node
12999 }
13001 /* If the second operand is NaN, the result is constant. */
13005 {
13007 ? integer_zero_node
13010 }
13012 /* Simplify unordered comparison of something with itself. */
13018 && !flag_trapping_math
13022 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
13023 {
13035 }
13040 /* When pedantic, a compound expression can be neither an lvalue
13041 nor an integer constant expression. */
13044 /* Don't let (0, 0) be null pointer constant. */
13058 /* An ASSERT_EXPR should never be passed to fold_binary. */
13064 fold_binary_exit:
13067 }
13069 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
13070 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
13071 of GOTO_EXPR. */
13073 static tree
13075 {
13077 {
13084 /* ... fall through ... */
13088 }
13089 }
13091 /* Return whether the sub-tree ST contains a label which is accessible from
13092 outside the sub-tree. */
13094 static bool
13096 {
13097 return
13099 }
13101 /* Fold a ternary expression of code CODE and type TYPE with operands
13102 OP0, OP1, and OP2. Return the folded expression if folding is
13103 successful. Otherwise, return NULL_TREE. */
13105 tree
13108 {
13109 tree tem;
13116 /* Strip any conversions that don't change the mode. This is safe
13117 for every expression, except for a comparison expression because
13118 its signedness is derived from its operands. So, in the latter
13119 case, only strip conversions that don't change the signedness.
13121 Note that this is done as an internal manipulation within the
13122 constant folder, in order to find the simplest representation of
13123 the arguments so that their form can be studied. In any cases,
13124 the appropriate type conversions should be put back in the tree
13125 that will get out of the constant folder. */
13127 {
13130 }
13133 {
13136 }
13139 {
13143 {
13149 }
13153 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
13154 so all simple results must be passed through pedantic_non_lvalue. */
13156 {
13159 /* Only optimize constant conditions when the selected branch
13160 has the same type as the COND_EXPR. This avoids optimizing
13161 away "c ? x : throw", where the throw has a void type.
13162 Avoid throwing away that operand which contains label. */
13169 }
13173 /* If we have A op B ? A : C, we may be able to convert this to a
13174 simpler expression, depending on the operation and the values
13175 of B and C. Signed zeros prevent all of these transformations,
13176 for reasons given above each one.
13178 Also try swapping the arguments and inverting the conditional. */
13183 {
13187 }
13191 op2,
13194 {
13197 {
13201 }
13202 }
13204 /* If the second operand is simpler than the third, swap them
13205 since that produces better jump optimization results. */
13208 {
13209 /* See if this can be inverted. If it can't, possibly because
13210 it was a floating-point inequality comparison, don't do
13211 anything. */
13215 }
13217 /* Convert A ? 1 : 0 to simply A. */
13220 /* If we try to convert OP0 to our type, the
13221 call to fold will try to move the conversion inside
13222 a COND, which will recurse. In that case, the COND_EXPR
13223 is probably the best choice, so leave it alone. */
13227 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13228 over COND_EXPR in cases such as floating point comparisons. */
13235 arg0)));
13237 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13242 {
13243 /* sign_bit_p only checks ARG1 bits within A's precision.
13244 If <sign bit of A> has wider type than A, bits outside
13245 of A's precision in <sign bit of A> need to be checked.
13246 If they are all 0, this optimization needs to be done
13247 in unsigned A's type, if they are all 1 in signed A's type,
13248 otherwise this can't be done. */
13253 {
13255 HOST_WIDE_INT mask_hi;
13257 tree tem_type;
13265 {
13269 }
13270 else
13271 {
13275 }
13277 {
13281 }
13282 else
13288 {
13291 }
13294 {
13297 }
13298 else
13300 }
13303 return
13309 arg1)));
13310 }
13312 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13313 already handled above. */
13318 {
13327 }
13329 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13330 is probably obsolete because the first operand should be a
13331 truth value (that's why we have the two cases above), but let's
13332 leave it in until we can confirm this for all front-ends. */
13344 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13350 arg1);
13352 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13356 {
13357 /* Only perform transformation if ARG0 is easily inverted. */
13362 arg1);
13363 }
13365 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13369 {
13370 /* Only perform transformation if ARG0 is easily inverted. */
13375 op2);
13376 }
13378 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13384 op2);
13389 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13390 of fold_ternary on them. */
13397 {
13406 {
13411 else
13412 {
13414 tree value;
13418 }
13423 else
13425 }
13426 }
13428 /* A bit-field-ref that referenced the full argument can be stripped. */
13439 }
13441 /* Perform constant folding and related simplification of EXPR.
13442 The related simplifications include x*1 => x, x*0 => 0, etc.,
13443 and application of the associative law.
13444 NOP_EXPR conversions may be removed freely (as long as we
13445 are careful not to change the type of the overall expression).
13446 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13447 but we can constant-fold them if they have constant operands. */
13449 #ifdef ENABLE_FOLD_CHECKING
13450 # define fold(x) fold_1 (x)
13452 static
13453 #endif
13454 tree
13456 {
13460 tree tem;
13463 /* Return right away if a constant. */
13467 /* CALL_EXPR-like objects with variable numbers of operands are
13468 treated specially. */
13470 {
13472 {
13475 }
13477 }
13480 {
13485 {
13503 }
13504 }
13507 {
13509 {
13516 {
13521 /* Find a matching index by means of a binary search. */
13523 {
13539 else
13541 }
13542 }
13545 }
13553 }
13555 #ifdef ENABLE_FOLD_CHECKING
13556 #undef fold
13562 /* When --enable-checking=fold, compute a digest of expr before
13563 and after actual fold call to see if fold did not accidentally
13564 change original expr. */
13566 tree
13568 {
13569 tree ret;
13572 htab_t ht;
13591 }
13593 void
13595 {
13598 htab_t ht;
13608 }
13610 static void
13612 {
13614 }
13616 static void
13618 {
13624 recursive_label:
13638 {
13639 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13643 }
13650 {
13651 /* Allow these fields to be modified. */
13652 tree tmp;
13660 {
13663 }
13664 }
13673 {
13676 {
13690 }
13694 {
13707 }
13724 {
13730 }
13735 {
13739 }
13750 {
13753 }
13763 }
13764 }
13766 /* Helper function for outputting the checksum of a tree T. When
13767 debugging with gdb, you can "define mynext" to be "next" followed
13768 by "call debug_fold_checksum (op0)", then just trace down till the
13769 outputs differ. */
13771 DEBUG_FUNCTION void
13773 {
13788 }
13790 #endif
13792 /* Fold a unary tree expression with code CODE of type TYPE with an
13793 operand OP0. LOC is the location of the resulting expression.
13794 Return a folded expression if successful. Otherwise, return a tree
13795 expression with code CODE of type TYPE with an operand OP0. */
13797 tree
13800 {
13801 tree tem;
13802 #ifdef ENABLE_FOLD_CHECKING
13805 htab_t ht;
13812 #endif
13816 {
13819 }
13821 #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
13851 htab_t ht;
13863 #endif
13867 {
13870 }
13872 #ifdef ENABLE_FOLD_CHECKING
13888 #endif
13890 }
13892 /* Fold a ternary tree expression with code CODE of type TYPE with
13893 operands OP0, OP1, and OP2. Return a folded expression if
13894 successful. Otherwise, return a tree expression with code CODE of
13895 type TYPE with operands OP0, OP1, and OP2. */
13897 tree
13900 {
13901 tree tem;
13902 #ifdef ENABLE_FOLD_CHECKING
13910 htab_t ht;
13927 #endif
13932 {
13935 }
13937 #ifdef ENABLE_FOLD_CHECKING
13961 #endif
13963 }
13965 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13966 arguments in ARGARRAY, and a null static chain.
13967 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13968 of type TYPE from the given operands as constructed by build_call_array. */
13970 tree
13973 {
13974 tree tem;
13975 #ifdef ENABLE_FOLD_CHECKING
13981 htab_t ht;
13995 #endif
13999 #ifdef ENABLE_FOLD_CHECKING
14016 #endif
14018 }
14020 /* Perform constant folding and related simplification of initializer
14021 expression EXPR. These behave identically to "fold_buildN" but ignore
14022 potential run-time traps and exceptions that fold must preserve. */
14024 #define START_FOLD_INIT \
14025 int saved_signaling_nans = flag_signaling_nans;\
14026 int saved_trapping_math = flag_trapping_math;\
14027 int saved_rounding_math = flag_rounding_math;\
14028 int saved_trapv = flag_trapv;\
14029 int saved_folding_initializer = folding_initializer;\
14030 flag_signaling_nans = 0;\
14031 flag_trapping_math = 0;\
14032 flag_rounding_math = 0;\
14033 flag_trapv = 0;\
14034 folding_initializer = 1;
14036 #define END_FOLD_INIT \
14037 flag_signaling_nans = saved_signaling_nans;\
14038 flag_trapping_math = saved_trapping_math;\
14039 flag_rounding_math = saved_rounding_math;\
14040 flag_trapv = saved_trapv;\
14041 folding_initializer = saved_folding_initializer;
14043 tree
14046 {
14047 tree result;
14048 START_FOLD_INIT;
14052 END_FOLD_INIT;
14054 }
14056 tree
14059 {
14060 tree result;
14061 START_FOLD_INIT;
14065 END_FOLD_INIT;
14067 }
14069 tree
14072 {
14073 tree result;
14074 START_FOLD_INIT;
14078 END_FOLD_INIT;
14080 }
14082 tree
14085 {
14086 tree result;
14087 START_FOLD_INIT;
14091 END_FOLD_INIT;
14093 }
14095 #undef START_FOLD_INIT
14096 #undef END_FOLD_INIT
14098 /* Determine if first argument is a multiple of second argument. Return 0 if
14099 it is not, or we cannot easily determined it to be.
14101 An example of the sort of thing we care about (at this point; this routine
14102 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14103 fold cases do now) is discovering that
14105 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14107 is a multiple of
14109 SAVE_EXPR (J * 8)
14111 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14113 This code also handles discovering that
14115 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14117 is a multiple of 8 so we don't have to worry about dealing with a
14118 possible remainder.
14120 Note that we *look* inside a SAVE_EXPR only to determine how it was
14121 calculated; it is not safe for fold to do much of anything else with the
14122 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14123 at run time. For example, the latter example above *cannot* be implemented
14124 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14125 evaluation time of the original SAVE_EXPR is not necessarily the same at
14126 the time the new expression is evaluated. The only optimization of this
14127 sort that would be valid is changing
14129 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14131 divided by 8 to
14133 SAVE_EXPR (I) * SAVE_EXPR (J)
14135 (where the same SAVE_EXPR (J) is used in the original and the
14136 transformed version). */
14138 int
14140 {
14148 {
14150 /* Bitwise and provides a power of two multiple. If the mask is
14151 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14154 /* FALLTHRU */
14167 {
14171 /* const_binop may not detect overflow correctly,
14172 so check for it explicitly here. */
14178 size_one_node,
14182 }
14186 /* Can't handle conversions from non-integral or wider integral type. */
14192 /* .. fall through ... */
14213 }
14214 }
14216 /* Return true if CODE or TYPE is known to be non-negative. */
14218 static bool
14220 {
14223 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14224 have a signed:1 type (where the value is -1 and 0). */
14227 }
14229 /* Return true if (CODE OP0) is known to be non-negative. If the return
14230 value is based on the assumption that signed overflow is undefined,
14231 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14232 *STRICT_OVERFLOW_P. */
14234 bool
14237 {
14242 {
14244 /* We can't return 1 if flag_wrapv is set because
14245 ABS_EXPR<INT_MIN> = INT_MIN. */
14249 {
14252 }
14259 strict_overflow_p);
14262 {
14267 {
14270 strict_overflow_p);
14272 {
14276 strict_overflow_p);
14277 }
14278 }
14280 {
14283 strict_overflow_p);
14287 }
14288 }
14293 }
14295 /* We don't know sign of `t', so be conservative and return false. */
14297 }
14299 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14300 value is based on the assumption that signed overflow is undefined,
14301 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14302 *STRICT_OVERFLOW_P. */
14304 bool
14307 {
14312 {
14317 strict_overflow_p)
14319 strict_overflow_p));
14321 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14322 both unsigned and at least 2 bits shorter than the result. */
14326 {
14331 {
14335 }
14336 }
14341 {
14342 /* x * x for floating point x is always non-negative. */
14346 strict_overflow_p)
14348 strict_overflow_p));
14349 }
14351 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14352 both unsigned and their total bits is shorter than the result. */
14356 {
14375 {
14385 }
14386 }
14392 strict_overflow_p)
14394 strict_overflow_p));
14405 strict_overflow_p)
14407 strict_overflow_p));
14414 strict_overflow_p);
14417 }
14419 /* We don't know sign of `t', so be conservative and return false. */
14421 }
14423 /* Return true if T is known to be non-negative. If the return
14424 value is based on the assumption that signed overflow is undefined,
14425 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14426 *STRICT_OVERFLOW_P. */
14428 bool
14430 {
14435 {
14447 strict_overflow_p)
14449 strict_overflow_p));
14453 }
14454 /* We don't know sign of `t', so be conservative and return false. */
14456 }
14458 /* Return true if T is known to be non-negative. If the return
14459 value is based on the assumption that signed overflow is undefined,
14460 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14461 *STRICT_OVERFLOW_P. */
14463 bool
14466 {
14469 {
14487 /* Always true. */
14491 /* sqrt(-0.0) is -0.0. */
14495 strict_overflow_p);
14528 /* True if the 1st argument is nonnegative. */
14530 strict_overflow_p);
14533 /* True if the 1st OR 2nd arguments are nonnegative. */
14535 strict_overflow_p)
14537 strict_overflow_p)));
14540 /* True if the 1st AND 2nd arguments are nonnegative. */
14542 strict_overflow_p)
14544 strict_overflow_p)));
14547 /* True if the 2nd argument is nonnegative. */
14549 strict_overflow_p);
14552 /* True if the 1st argument is nonnegative or the second
14553 argument is an even integer. */
14558 strict_overflow_p);
14561 /* True if the 1st argument is nonnegative or the second
14562 argument is an even integer valued real. */
14564 {
14565 REAL_VALUE_TYPE c;
14566 HOST_WIDE_INT n;
14571 {
14572 REAL_VALUE_TYPE cint;
14577 }
14578 }
14580 strict_overflow_p);
14584 }
14586 type);
14587 }
14589 /* Return true if T is known to be non-negative. If the return
14590 value is based on the assumption that signed overflow is undefined,
14591 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14592 *STRICT_OVERFLOW_P. */
14594 bool
14596 {
14602 {
14604 {
14608 /* If the initializer is non-void, then it's a normal expression
14609 that will be assigned to the slot. */
14613 /* Otherwise, the initializer sets the slot in some way. One common
14614 way is an assignment statement at the end of the initializer. */
14616 {
14624 else
14626 }
14630 strict_overflow_p);
14633 }
14636 {
14642 arg0,
14643 arg1,
14644 strict_overflow_p);
14645 }
14649 strict_overflow_p);
14652 strict_overflow_p);
14655 strict_overflow_p);
14660 }
14662 /* We don't know sign of `t', so be conservative and return false. */
14664 }
14666 /* Return true if T is known to be non-negative. If the return
14667 value is based on the assumption that signed overflow is undefined,
14668 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14669 *STRICT_OVERFLOW_P. */
14671 bool
14673 {
14680 {
14687 strict_overflow_p);
14693 strict_overflow_p);
14702 }
14705 {
14713 strict_overflow_p);
14718 strict_overflow_p);
14731 }
14732 }
14734 /* Return true if `t' is known to be non-negative. Handle warnings
14735 about undefined signed overflow. */
14737 bool
14739 {
14746 "determining that expression is always "
14748 WARN_STRICT_OVERFLOW_MISC);
14750 }
14753 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14754 For floating point we further ensure that T is not denormal.
14755 Similar logic is present in nonzero_address in rtlanal.h.
14757 If the return value is based on the assumption that signed overflow
14758 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14759 change *STRICT_OVERFLOW_P. */
14761 bool
14764 {
14766 {
14769 strict_overflow_p);
14772 {
14778 strict_overflow_p));
14779 }
14784 strict_overflow_p);
14788 }
14791 }
14793 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14794 For floating point we further ensure that T is not denormal.
14795 Similar logic is present in nonzero_address in rtlanal.h.
14797 If the return value is based on the assumption that signed overflow
14798 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14799 change *STRICT_OVERFLOW_P. */
14801 bool
14803 tree type,
14804 tree op0,
14806 {
14809 {
14813 {
14814 /* With the presence of negative values it is hard
14815 to say something. */
14822 /* One of operands must be positive and the other non-negative. */
14823 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14824 overflows, on a twos-complement machine the sum of two
14825 nonnegative numbers can never be zero. */
14827 strict_overflow_p)
14829 strict_overflow_p));
14830 }
14835 {
14837 strict_overflow_p)
14839 strict_overflow_p))
14840 {
14843 }
14844 }
14853 {
14856 }
14863 {
14867 /* When both operands are nonzero, then MAX must be too. */
14869 strict_overflow_p))
14872 /* MAX where operand 0 is positive is positive. */
14874 strict_overflow_p);
14875 }
14876 /* MAX where operand 1 is positive is positive. */
14881 {
14885 }
14890 strict_overflow_p)
14892 strict_overflow_p));
14896 }
14899 }
14901 /* Return true when T is an address and is known to be nonzero.
14902 For floating point we further ensure that T is not denormal.
14903 Similar logic is present in nonzero_address in rtlanal.h.
14905 If the return value is based on the assumption that signed overflow
14906 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14907 change *STRICT_OVERFLOW_P. */
14909 bool
14911 {
14914 {
14919 {
14927 /* Weak declarations may link to NULL. Other things may also be NULL
14928 so protect with -fdelete-null-pointer-checks; but not variables
14929 allocated on the stack. */
14931 && (flag_delete_null_pointer_checks
14937 /* Constants are never weak. */
14942 }
14950 {
14954 }
14959 }
14961 }
14963 /* Return true when T is an address and is known to be nonzero.
14964 For floating point we further ensure that T is not denormal.
14965 Similar logic is present in nonzero_address in rtlanal.h.
14967 If the return value is based on the assumption that signed overflow
14968 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14969 change *STRICT_OVERFLOW_P. */
14971 bool
14973 {
14977 /* Doing something useful for floating point would need more work. */
14983 {
14986 strict_overflow_p);
14992 strict_overflow_p);
15000 }
15003 {
15006 strict_overflow_p);
15014 strict_overflow_p);
15029 strict_overflow_p);
15033 strict_overflow_p);
15040 }
15042 }
15044 /* Return true when T is an address and is known to be nonzero.
15045 Handle warnings about undefined signed overflow. */
15047 bool
15049 {
15056 "determining that expression is always "
15058 WARN_STRICT_OVERFLOW_MISC);
15060 }
15062 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15063 attempt to fold the expression to a constant without modifying TYPE,
15064 OP0 or OP1.
15066 If the expression could be simplified to a constant, then return
15067 the constant. If the expression would not be simplified to a
15068 constant, then return NULL_TREE. */
15070 tree
15072 {
15075 }
15077 /* Given the components of a unary expression CODE, TYPE and OP0,
15078 attempt to fold the expression to a constant without modifying
15079 TYPE or OP0.
15081 If the expression could be simplified to a constant, then return
15082 the constant. If the expression would not be simplified to a
15083 constant, then return NULL_TREE. */
15085 tree
15087 {
15090 }
15092 /* If EXP represents referencing an element in a constant string
15093 (either via pointer arithmetic or array indexing), return the
15094 tree representing the value accessed, otherwise return NULL. */
15096 tree
15098 {
15102 {
15104 tree index;
15105 tree string;
15110 else
15111 {
15115 /* Optimize the special-case of a zero lower bound.
15117 We convert the low_bound to sizetype to avoid some problems
15118 with constant folding. (E.g. suppose the lower bound is 1,
15119 and its mode is QI. Without the conversion,l (ARRAY
15120 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15121 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15127 }
15140 }
15142 }
15144 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15145 an integer constant, real, or fixed-point constant.
15147 TYPE is the type of the result. */
15149 static tree
15151 {
15155 {
15157 {
15159 HOST_WIDE_INT high;
15167 }
15174 {
15175 FIXED_VALUE_TYPE f;
15180 /* Propagate overflow flags. */
15184 }
15188 }
15191 }
15193 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15194 an integer constant or real constant.
15196 TYPE is the type of the result. */
15198 tree
15200 {
15204 {
15206 /* If the value is unsigned, then the absolute value is
15207 the same as the ordinary value. */
15210 /* Similarly, if the value is non-negative. */
15213 /* If the value is negative, then the absolute value is
15214 its negation. */
15215 else
15216 {
15218 HOST_WIDE_INT high;
15224 }
15230 else
15236 }
15239 }
15241 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15242 constant. TYPE is the type of the result. */
15244 static tree
15246 {
15256 }
15258 /* Given CODE, a relational operator, the target type, TYPE and two
15259 constant operands OP0 and OP1, return the result of the
15260 relational operation. If the result is not a compile time
15261 constant, then return NULL_TREE. */
15263 static tree
15265 {
15268 /* From here on, the only cases we handle are when the result is
15269 known to be a constant. */
15272 {
15276 /* Handle the cases where either operand is a NaN. */
15278 {
15280 {
15308 }
15311 }
15314 }
15317 {
15321 }
15323 /* Handle equality/inequality of complex constants. */
15325 {
15336 else
15338 }
15340 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15342 To compute GT, swap the arguments and do LT.
15343 To compute GE, do LT and invert the result.
15344 To compute LE, swap the arguments, do LT and invert the result.
15345 To compute NE, do EQ and invert the result.
15347 Therefore, the code below must handle only EQ and LT. */
15350 {
15355 }
15357 /* Note that it is safe to invert for real values here because we
15358 have already handled the one case that it matters. */
15362 {
15365 }
15367 /* Compute a result for LT or EQ if args permit;
15368 Otherwise return T. */
15370 {
15375 else
15377 }
15378 else
15384 }
15386 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15387 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15388 itself. */
15390 tree
15392 {
15393 /* If the expression does not have side effects then we don't have to wrap
15394 it with a cleanup point expression. */
15398 /* If the expression is a return, check to see if the expression inside the
15399 return has no side effects or the right hand side of the modify expression
15400 inside the return. If either don't have side effects set we don't need to
15401 wrap the expression in a cleanup point expression. Note we don't check the
15402 left hand side of the modify because it should always be a return decl. */
15404 {
15411 }
15414 }
15416 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15417 of an indirection through OP0, or NULL_TREE if no simplification is
15418 possible. */
15420 tree
15422 {
15424 tree subtype;
15432 {
15435 /* *&CONST_DECL -> to the value of the const decl. */
15438 /* *&p => p; make sure to handle *&"str"[cst] here. */
15440 {
15444 else
15446 }
15447 /* *(foo *)&fooarray => fooarray[0] */
15450 {
15458 }
15459 /* *(foo *)&complexfoo => __real__ complexfoo */
15463 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15466 {
15470 }
15471 }
15473 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15476 {
15479 tree op00type;
15486 {
15498 }
15499 }
15502 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15505 {
15508 tree op00type;
15515 {
15520 }
15521 }
15523 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15526 {
15527 tree type_domain;
15536 }
15539 }
15541 /* Builds an expression for an indirection through T, simplifying some
15542 cases. */
15544 tree
15546 {
15556 }
15558 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15560 tree
15562 {
15567 else
15569 }
15571 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15572 whose result is ignored. The type of the returned tree need not be
15573 the same as the original expression. */
15575 tree
15577 {
15583 {
15594 else
15600 {
15616 }
15621 }
15622 }
15624 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15625 This can only be applied to objects of a sizetype. */
15627 tree
15629 {
15636 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15637 have to do anything. Only do this when we are not given a const,
15638 because in that case, this check is more expensive than just
15639 doing it. */
15641 {
15646 }
15648 /* If divisor is a power of two, simplify this to bit manipulation. */
15650 {
15652 {
15665 {
15666 high++;
15669 }
15673 }
15674 else
15675 {
15676 tree t;
15682 }
15683 }
15684 else
15685 {
15690 }
15693 }
15695 /* Likewise, but round down. */
15697 tree
15699 {
15706 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15707 have to do anything. Only do this when we are not given a const,
15708 because in that case, this check is more expensive than just
15709 doing it. */
15711 {
15716 }
15718 /* If divisor is a power of two, simplify this to bit manipulation. */
15720 {
15721 tree t;
15725 }
15726 else
15727 {
15732 }
15735 }
15737 /* Returns the pointer to the base of the object addressed by EXP and
15738 extracts the information about the offset of the access, storing it
15739 to PBITPOS and POFFSET. */
15741 static tree
15744 {
15745 tree core;
15748 HOST_WIDE_INT bitsize;
15752 {
15757 }
15758 else
15759 {
15763 }
15766 }
15768 /* Returns true if addresses of E1 and E2 differ by a constant, false
15769 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15771 bool
15773 {
15787 {
15797 }
15799 {
15800 /* If only one of the offsets is non-constant, the difference cannot
15801 be a constant. */
15803 }
15804 else
15809 }
15811 /* Simplify the floating point expression EXP when the sign of the
15812 result is not significant. Return NULL_TREE if no simplification
15813 is possible. */
15815 tree
15817 {
15822 {
15858 {
15861 {
15863 /* Strip copysign function call, return the 1st argument. */
15869 /* Strip sign ops from the argument of "odd" math functions. */
15871 {
15875 }
15877 }
15878 }
15883 }
15885 }