| blob | 65ded14e95fe2a5f08a3e97840e09025a4f6102f |
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. */
68 /* Nonzero if we are folding constants inside an initializer; zero
69 otherwise. */
72 /* The following constants represent a bit based encoding of GCC's
73 comparison operators. This encoding simplifies transformations
74 on relational comparison operators, such as AND and OR. */
92 };
112 HOST_WIDE_INT *,
148 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
149 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
150 and SUM1. Then this yields nonzero if overflow occurred during the
151 addition.
153 Overflow occurs if A and B have the same sign, but A and SUM differ in
154 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
155 sign. */
156 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
157 \f
158 /* If ARG2 divides ARG1 with zero remainder, carries out the division
159 of type CODE and returns the quotient.
160 Otherwise returns NULL_TREE. */
162 tree
164 {
168 /* The sign of the division is according to operand two, that
169 does the correct thing for POINTER_PLUS_EXPR where we want
170 a signed division. */
184 }
185 \f
186 /* This is nonzero if we should defer warnings about undefined
187 overflow. This facility exists because these warnings are a
188 special case. The code to estimate loop iterations does not want
189 to issue any warnings, since it works with expressions which do not
190 occur in user code. Various bits of cleanup code call fold(), but
191 only use the result if it has certain characteristics (e.g., is a
192 constant); that code only wants to issue a warning if the result is
193 used. */
197 /* If a warning about undefined overflow is deferred, this is the
198 warning. Note that this may cause us to turn two warnings into
199 one, but that is fine since it is sufficient to only give one
200 warning per expression. */
204 /* If a warning about undefined overflow is deferred, this is the
205 level at which the warning should be emitted. */
209 /* Start deferring overflow warnings. We could use a stack here to
210 permit nested calls, but at present it is not necessary. */
212 void
214 {
216 }
218 /* Stop deferring overflow warnings. If there is a pending warning,
219 and ISSUE is true, then issue the warning if appropriate. STMT is
220 the statement with which the warning should be associated (used for
221 location information); STMT may be NULL. CODE is the level of the
222 warning--a warn_strict_overflow_code value. This function will use
223 the smaller of CODE and the deferred code when deciding whether to
224 issue the warning. CODE may be zero to mean to always use the
225 deferred code. */
227 void
229 {
231 location_t locus;
236 {
242 }
253 /* Use the smallest code level when deciding to issue the
254 warning. */
263 else
266 }
268 /* Stop deferring overflow warnings, ignoring any deferred
269 warnings. */
271 void
273 {
275 }
277 /* Whether we are deferring overflow warnings. */
279 bool
281 {
283 }
285 /* This is called when we fold something based on the fact that signed
286 overflow is undefined. */
288 static void
290 {
292 {
295 {
298 }
299 }
302 }
303 \f
304 /* Return true if the built-in mathematical function specified by CODE
305 is odd, i.e. -f(x) == f(-x). */
307 static bool
309 {
311 {
345 }
347 }
349 /* Check whether we may negate an integer constant T without causing
350 overflow. */
352 bool
354 {
357 tree type;
367 {
372 }
373 else
378 }
380 /* Determine whether an expression T can be cheaply negated using
381 the function negate_expr without introducing undefined overflow. */
383 static bool
385 {
386 tree type;
395 {
400 /* Check that -CST will not overflow type. */
411 /* We want to canonicalize to positive real constants. Pretend
412 that only negative ones can be easily negated. */
430 /* -(A + B) -> (-B) - A. */
435 /* -(A + B) -> (-A) - B. */
439 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
449 /* Fall through. */
462 /* In general we can't negate A / B, because if A is INT_MIN and
463 B is 1, we may turn this into INT_MIN / -1 which is undefined
464 and actually traps on some architectures. But if overflow is
465 undefined, we can negate, because - (INT_MIN / 1) is an
466 overflow. */
474 /* Negate -((double)float) as (double)(-float). */
476 {
480 }
484 /* Negate -f(x) as f(-x). */
490 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
492 {
498 }
503 }
505 }
507 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
508 simplification is possible.
509 If negate_expr_p would return true for T, NULL_TREE will never be
510 returned. */
512 static tree
514 {
516 tree tem;
519 {
520 /* Convert - (~A) to A + 1. */
536 /* Two's complement FP formats, such as c4x, may overflow. */
546 {
555 }
577 {
578 /* -(A + B) -> (-B) - A. */
582 {
586 }
588 /* -(A + B) -> (-A) - B. */
590 {
594 }
595 }
599 /* - (A - B) -> B - A */
611 /* Fall through. */
615 {
624 }
632 /* In general we can't negate A / B, because if A is INT_MIN and
633 B is 1, we may turn this into INT_MIN / -1 which is undefined
634 and actually traps on some architectures. But if overflow is
635 undefined, we can negate, because - (INT_MIN / 1) is an
636 overflow. */
638 {
643 {
650 }
653 {
660 }
661 }
665 /* Convert -((double)float) into (double)(-float). */
667 {
671 }
675 /* Negate -f(x) as f(-x). */
678 {
684 }
688 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
690 {
695 {
702 }
703 }
708 }
711 }
713 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
714 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
715 return NULL_TREE. */
717 static tree
719 {
721 location_t loc;
732 {
735 }
737 }
738 \f
739 /* Split a tree IN into a constant, literal and variable parts that could be
740 combined with CODE to make IN. "constant" means an expression with
741 TREE_CONSTANT but that isn't an actual constant. CODE must be a
742 commutative arithmetic operation. Store the constant part into *CONP,
743 the literal in *LITP and return the variable part. If a part isn't
744 present, set it to null. If the tree does not decompose in this way,
745 return the entire tree as the variable part and the other parts as null.
747 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
748 case, we negate an operand that was subtracted. Except if it is a
749 literal for which we use *MINUS_LITP instead.
751 If NEGATE_P is true, we are negating all of IN, again except a literal
752 for which we use *MINUS_LITP instead.
754 If IN is itself a literal or constant, return it as appropriate.
756 Note that we do not guarantee that any of the three values will be the
757 same type as IN, but they will have the same signedness and mode. */
759 static tree
762 {
769 /* Strip any conversions that don't change the machine mode or signedness. */
778 /* We can associate addition and subtraction together (even
779 though the C standard doesn't say so) for integers because
780 the value is not affected. For reals, the value might be
781 affected, so we can't. */
784 {
790 /* First see if either of the operands is a literal, then a constant. */
803 /* If we haven't dealt with either operand, this is not a case we can
804 decompose. Otherwise, VAR is either of the ones remaining, if any. */
809 else
812 /* Now do any needed negations. */
819 }
822 else
826 {
833 }
836 }
838 /* Re-associate trees split by the above function. T1 and T2 are
839 either expressions to associate or null. Return the new
840 expression, if any. LOC is the location of the new expression. If
841 we build an operation, do it in TYPE and with CODE. */
843 static tree
845 {
846 tree tem;
853 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
854 try to fold this since we will have infinite recursion. But do
855 deal with any NEGATE_EXPRs. */
858 {
860 {
869 }
871 {
874 }
879 }
883 associate_trees_exit:
886 }
887 \f
888 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
889 for use in int_const_binop, size_binop and size_diffop. */
891 static bool
893 {
900 {
909 }
914 }
917 /* Combine two integer constants ARG1 and ARG2 under operation CODE
918 to produce a new constant. Return NULL_TREE if we don't know how
919 to evaluate CODE at compile-time.
921 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
923 tree
925 {
929 HOST_WIDE_INT hi;
931 HOST_WIDE_INT garbageh;
932 tree t;
935 int is_sizetype
945 {
961 /* It's unclear from the C standard whether shifts can overflow.
962 The following code ignores overflow; perhaps a C standard
963 interpretation ruling is needed. */
992 /* This is a shortcut for a common special case. */
997 {
1003 }
1005 /* ... fall through ... */
1011 {
1014 }
1017 {
1020 }
1027 /* This is a shortcut for a common special case. */
1032 {
1037 }
1039 /* ... fall through ... */
1057 else
1063 else
1069 }
1072 {
1075 /* Propagate overflow flags ourselves. */
1078 {
1081 }
1082 }
1083 else
1089 }
1091 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1092 constant. We assume ARG1 and ARG2 have the same data type, or at least
1093 are the same kind of constant and the same machine mode. Return zero if
1094 combining the constants is not allowed in the current operating mode.
1096 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1098 static tree
1100 {
1101 /* Sanity check for the recursive cases. */
1112 {
1114 REAL_VALUE_TYPE d1;
1115 REAL_VALUE_TYPE d2;
1116 REAL_VALUE_TYPE value;
1117 REAL_VALUE_TYPE result;
1121 /* The following codes are handled by real_arithmetic. */
1123 {
1134 }
1142 /* Don't perform operation if we honor signaling NaNs and
1143 either operand is a NaN. */
1148 /* Don't perform operation if it would raise a division
1149 by zero exception. */
1155 /* If either operand is a NaN, just return it. Otherwise, set up
1156 for floating-point trap; we return an overflow. */
1165 /* Don't constant fold this floating point operation if
1166 the result has overflowed and flag_trapping_math. */
1174 /* Don't constant fold this floating point operation if the
1175 result may dependent upon the run-time rounding mode and
1176 flag_rounding_math is set, or if GCC's software emulation
1177 is unable to accurately represent the result. */
1187 }
1190 {
1191 FIXED_VALUE_TYPE f1;
1192 FIXED_VALUE_TYPE f2;
1193 FIXED_VALUE_TYPE result;
1198 /* The following codes are handled by fixed_arithmetic. */
1200 {
1217 }
1224 /* Propagate overflow flags. */
1228 }
1231 {
1240 {
1251 mpc_mul);
1256 notrunc);
1260 notrunc);
1267 mpc_div);
1268 /* Fallthru ... */
1274 {
1275 /* Keep this algorithm in sync with
1276 tree-complex.c:expand_complex_div_straight().
1278 Expand complex division to scalars, straightforward algorithm.
1279 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1280 t = br*br + bi*bi
1281 */
1282 tree magsquared
1286 notrunc);
1287 tree t1
1291 notrunc);
1292 tree t2
1296 notrunc);
1300 }
1301 else
1302 {
1303 /* Keep this algorithm in sync with
1304 tree-complex.c:expand_complex_div_wide().
1306 Expand complex division to scalars, modified algorithm to minimize
1307 overflow with wide input ranges. */
1313 {
1314 /* In the TRUE branch, we compute
1315 ratio = br/bi;
1316 div = (br * ratio) + bi;
1317 tr = (ar * ratio) + ai;
1318 ti = (ai * ratio) - ar;
1319 tr = tr / div;
1320 ti = ti / div; */
1324 notrunc),
1325 notrunc);
1333 }
1334 else
1335 {
1336 /* In the FALSE branch, we compute
1337 ratio = d/c;
1338 divisor = (d * ratio) + c;
1339 tr = (b * ratio) + a;
1340 ti = b - (a * ratio);
1341 tr = tr / div;
1342 ti = ti / div; */
1346 notrunc),
1347 notrunc);
1356 }
1357 }
1362 }
1366 }
1369 {
1381 {
1384 /* The trailing elements can be empty and should be treated as 0 */
1387 else
1388 {
1391 }
1395 else
1396 {
1399 }
1403 /* It is possible that const_binop cannot handle the given
1404 code and return NULL_TREE */
1409 }
1411 }
1413 }
1415 /* Create a size type INT_CST node with NUMBER sign extended. KIND
1416 indicates which particular sizetype to create. */
1418 tree
1420 {
1422 }
1423 \f
1424 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1425 is a tree code. The type of the result is taken from the operands.
1426 Both must be equivalent integer types, ala int_binop_types_match_p.
1427 If the operands are constant, so is the result. */
1429 tree
1431 {
1440 /* Handle the special case of two integer constants faster. */
1442 {
1443 /* And some specific cases even faster than that. */
1445 {
1450 }
1452 {
1455 }
1457 {
1460 }
1462 /* Handle general case of two integer constants. */
1464 }
1467 }
1469 /* Given two values, either both of sizetype or both of bitsizetype,
1470 compute the difference between the two values. Return the value
1471 in signed type corresponding to the type of the operands. */
1473 tree
1475 {
1477 tree ctype;
1482 /* If the type is already signed, just do the simple thing. */
1490 else
1493 /* If either operand is not a constant, do the conversions to the signed
1494 type and subtract. The hardware will do the right thing with any
1495 overflow in the subtraction. */
1501 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1502 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1503 overflow) and negate (which can't either). Special-case a result
1504 of zero while we're here. */
1510 else
1514 MINUS_EXPR,
1516 }
1517 \f
1518 /* A subroutine of fold_convert_const handling conversions of an
1519 INTEGER_CST to another integer type. */
1521 static tree
1523 {
1524 tree t;
1526 /* Given an integer constant, make new constant with new type,
1527 appropriately sign-extended or truncated. */
1537 }
1539 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1540 to an integer type. */
1542 static tree
1544 {
1546 tree t;
1548 /* The following code implements the floating point to integer
1549 conversion rules required by the Java Language Specification,
1550 that IEEE NaNs are mapped to zero and values that overflow
1551 the target precision saturate, i.e. values greater than
1552 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1553 are mapped to INT_MIN. These semantics are allowed by the
1554 C and C++ standards that simply state that the behavior of
1555 FP-to-integer conversion is unspecified upon overflow. */
1557 double_int val;
1558 REAL_VALUE_TYPE r;
1562 {
1569 }
1571 /* If R is NaN, return zero and show we have an overflow. */
1573 {
1576 }
1578 /* See if R is less than the lower bound or greater than the
1579 upper bound. */
1582 {
1586 {
1589 }
1590 }
1593 {
1596 {
1599 {
1602 }
1603 }
1604 }
1612 }
1614 /* A subroutine of fold_convert_const handling conversions of a
1615 FIXED_CST to an integer type. */
1617 static tree
1619 {
1620 tree t;
1624 /* Right shift FIXED_CST to temp by fbit. */
1628 {
1630 HOST_BITS_PER_DOUBLE_INT,
1633 /* Left shift temp to temp_trunc by fbit. */
1635 HOST_BITS_PER_DOUBLE_INT,
1637 }
1638 else
1639 {
1642 }
1644 /* If FIXED_CST is negative, we need to round the value toward 0.
1645 By checking if the fractional bits are not zero to add 1 to temp. */
1651 /* Given a fixed-point constant, make new constant with new type,
1652 appropriately sign-extended or truncated. */
1660 }
1662 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1663 to another floating point type. */
1665 static tree
1667 {
1668 REAL_VALUE_TYPE value;
1669 tree t;
1674 /* If converting an infinity or NAN to a representation that doesn't
1675 have one, set the overflow bit so that we can produce some kind of
1676 error message at the appropriate point if necessary. It's not the
1677 most user-friendly message, but it's better than nothing. */
1684 /* Regular overflow, conversion produced an infinity in a mode that
1685 can't represent them. */
1690 else
1693 }
1695 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1696 to a floating point type. */
1698 static tree
1700 {
1701 REAL_VALUE_TYPE value;
1702 tree t;
1709 }
1711 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1712 to another fixed-point type. */
1714 static tree
1716 {
1717 FIXED_VALUE_TYPE value;
1718 tree t;
1725 /* Propagate overflow flags. */
1729 }
1731 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
1732 to a fixed-point type. */
1734 static tree
1736 {
1737 FIXED_VALUE_TYPE value;
1738 tree t;
1747 /* Propagate overflow flags. */
1751 }
1753 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1754 to a fixed-point type. */
1756 static tree
1758 {
1759 FIXED_VALUE_TYPE value;
1760 tree t;
1768 /* Propagate overflow flags. */
1772 }
1774 /* Attempt to fold type conversion operation CODE of expression ARG1 to
1775 type TYPE. If no simplification can be done return NULL_TREE. */
1777 static tree
1779 {
1785 {
1792 }
1794 {
1801 }
1803 {
1810 }
1812 }
1814 /* Construct a vector of zero elements of vector type TYPE. */
1816 static tree
1818 {
1829 }
1831 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
1833 bool
1835 {
1850 {
1869 }
1870 }
1872 /* Convert expression ARG to type TYPE. Used by the middle-end for
1873 simple conversions in preference to calling the front-end's convert. */
1875 tree
1877 {
1879 tree tem;
1893 {
1896 /* Handle conversions between pointers to different address spaces. */
1901 /* fall through */
1906 {
1910 }
1924 {
1928 }
1930 {
1934 }
1936 {
1940 }
1943 {
1961 }
1966 {
1970 }
1973 {
1987 }
1991 {
2000 integer_zero_node));
2002 {
2006 {
2012 }
2020 }
2024 }
2042 }
2043 fold_convert_exit:
2046 }
2047 \f
2048 /* Return false if expr can be assumed not to be an lvalue, true
2049 otherwise. */
2051 static bool
2053 {
2054 /* We only need to wrap lvalue tree codes. */
2056 {
2088 /* Assume the worst for front-end tree codes. */
2092 }
2095 }
2097 /* Return an expr equal to X but certainly not valid as an lvalue. */
2099 tree
2101 {
2102 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2103 us. */
2112 }
2114 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2115 Zero means allow extended lvalues. */
2119 /* When pedantic, return an expr equal to X but certainly not valid as a
2120 pedantic lvalue. Otherwise, return X. */
2122 static tree
2124 {
2129 }
2130 \f
2131 /* Given a tree comparison code, return the code that is the logical inverse
2132 of the given code. It is not safe to do this for floating-point
2133 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2134 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2136 enum tree_code
2138 {
2143 {
2174 }
2175 }
2177 /* Similar, but return the comparison that results if the operands are
2178 swapped. This is safe for floating-point. */
2180 enum tree_code
2182 {
2184 {
2210 }
2211 }
2214 /* Convert a comparison tree code from an enum tree_code representation
2215 into a compcode bit-based encoding. This function is the inverse of
2216 compcode_to_comparison. */
2218 static enum comparison_code
2220 {
2222 {
2253 }
2254 }
2256 /* Convert a compcode bit-based encoding of a comparison operator back
2257 to GCC's enum tree_code representation. This function is the
2258 inverse of comparison_to_compcode. */
2260 static enum tree_code
2262 {
2264 {
2295 }
2296 }
2298 /* Return a tree for the comparison which is the combination of
2299 doing the AND or OR (depending on CODE) of the two operations LCODE
2300 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2301 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2302 if this makes the transformation invalid. */
2304 tree
2309 {
2316 {
2327 }
2330 {
2331 /* Eliminate unordered comparisons, as well as LTGT and ORD
2332 which are not used unless the mode has NaNs. */
2338 }
2340 {
2341 /* Check that the original operation and the optimized ones will trap
2342 under the same condition. */
2353 /* In a short-circuited boolean expression the LHS might be
2354 such that the RHS, if evaluated, will never trap. For
2355 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2356 if neither x nor y is NaN. (This is a mixed blessing: for
2357 example, the expression above will never trap, hence
2358 optimizing it to x < y would be invalid). */
2363 /* If the comparison was short-circuited, and only the RHS
2364 trapped, we may now generate a spurious trap. */
2369 /* If we changed the conditions that cause a trap, we lose. */
2372 }
2378 else
2379 {
2384 }
2385 }
2386 \f
2387 /* Return nonzero if two operands (typically of the same tree node)
2388 are necessarily equal. If either argument has side-effects this
2389 function returns zero. FLAGS modifies behavior as follows:
2391 If OEP_ONLY_CONST is set, only return nonzero for constants.
2392 This function tests whether the operands are indistinguishable;
2393 it does not test whether they are equal using C's == operation.
2394 The distinction is important for IEEE floating point, because
2395 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2396 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2398 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2399 even though it may hold multiple values during a function.
2400 This is because a GCC tree node guarantees that nothing else is
2401 executed between the evaluation of its "operands" (which may often
2402 be evaluated in arbitrary order). Hence if the operands themselves
2403 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2404 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2405 unset means assuming isochronic (or instantaneous) tree equivalence.
2406 Unless comparing arbitrary expression trees, such as from different
2407 statements, this flag can usually be left unset.
2409 If OEP_PURE_SAME is set, then pure functions with identical arguments
2410 are considered the same. It is used when the caller has other ways
2411 to ensure that global memory is unchanged in between. */
2413 int
2415 {
2416 /* If either is ERROR_MARK, they aren't equal. */
2422 /* Similar, if either does not have a type (like a released SSA name),
2423 they aren't equal. */
2427 /* Check equality of integer constants before bailing out due to
2428 precision differences. */
2432 /* If both types don't have the same signedness, then we can't consider
2433 them equal. We must check this before the STRIP_NOPS calls
2434 because they may change the signedness of the arguments. As pointers
2435 strictly don't have a signedness, require either two pointers or
2436 two non-pointers as well. */
2441 /* We cannot consider pointers to different address space equal. */
2447 /* If both types don't have the same precision, then it is not safe
2448 to strip NOPs. */
2455 /* In case both args are comparisons but with different comparison
2456 code, try to swap the comparison operands of one arg to produce
2457 a match and compare that variant. */
2461 {
2469 }
2472 /* This is needed for conversions and for COMPONENT_REF.
2473 Might as well play it safe and always test this. */
2479 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2480 We don't care about side effects in that case because the SAVE_EXPR
2481 takes care of that for us. In all other cases, two expressions are
2482 equal if they have no side effects. If we have two identical
2483 expressions with side effects that should be treated the same due
2484 to the only side effects being identical SAVE_EXPR's, that will
2485 be detected in the recursive calls below. */
2491 /* Next handle constant cases, those for which we can return 1 even
2492 if ONLY_CONST is set. */
2495 {
2510 {
2511 /* If we do not distinguish between signed and unsigned zero,
2512 consider them equal. */
2515 }
2519 {
2525 {
2527 flags))
2531 }
2534 }
2538 flags)
2540 flags));
2553 }
2558 /* Define macros to test an operand from arg0 and arg1 for equality and a
2559 variant that allows null and views null as being different from any
2560 non-null value. In the latter case, if either is null, the both
2561 must be; otherwise, do the normal comparison. */
2562 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2563 TREE_OPERAND (arg1, N), flags)
2565 #define OP_SAME_WITH_NULL(N) \
2566 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2567 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2570 {
2572 /* Two conversions are equal only if signedness and modes match. */
2574 {
2575 CASE_CONVERT:
2583 }
2593 /* For commutative ops, allow the other order. */
2601 /* If either of the pointer (or reference) expressions we are
2602 dereferencing contain a side effect, these cannot be equal. */
2608 {
2618 /* Operands 2 and 3 may be null.
2619 Compare the array index by value if it is constant first as we
2620 may have different types but same value here. */
2629 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
2630 may be NULL when we're called to compare MEM_EXPRs. */
2640 }
2644 {
2659 /* Otherwise take into account this is a commutative operation. */
2670 }
2674 {
2676 /* If the CALL_EXPRs call different functions, then they
2677 clearly can not be equal. */
2679 flags))
2682 {
2686 else
2690 }
2692 /* Now see if all the arguments are the same. */
2693 {
2704 /* If we get here and both argument lists are exhausted
2705 then the CALL_EXPRs are equal. */
2707 }
2710 }
2713 /* Consider __builtin_sqrt equal to sqrt. */
2721 }
2723 #undef OP_SAME
2724 #undef OP_SAME_WITH_NULL
2725 }
2726 \f
2727 /* Similar to operand_equal_p, but see if ARG0 might have been made by
2728 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
2730 When in doubt, return 0. */
2732 static int
2734 {
2746 /* Discard any conversions that don't change the modes of ARG0 and ARG1
2747 and see if the inner values are the same. This removes any
2748 signedness comparison, which doesn't matter here. */
2755 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
2756 actual comparison operand, ARG0.
2758 First throw away any conversions to wider types
2759 already present in the operands. */
2768 {
2771 /* Make sure shorter operand is extended the right way
2772 to match the longer operand. */
2778 }
2781 }
2782 \f
2783 /* See if ARG is an expression that is either a comparison or is performing
2784 arithmetic on comparisons. The comparisons must only be comparing
2785 two different values, which will be stored in *CVAL1 and *CVAL2; if
2786 they are nonzero it means that some operands have already been found.
2787 No variables may be used anywhere else in the expression except in the
2788 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2789 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2791 If this is true, return 1. Otherwise, return zero. */
2793 static int
2795 {
2799 /* We can handle some of the tcc_expression cases here. */
2809 {
2810 /* If we've already found a CVAL1 or CVAL2, this expression is
2811 two complex to handle. */
2817 }
2820 {
2843 /* First see if we can handle the first operand, then the second. For
2844 the second operand, we know *CVAL1 can't be zero. It must be that
2845 one side of the comparison is each of the values; test for the
2846 case where this isn't true by failing if the two operands
2847 are the same. */
2856 ;
2860 ;
2861 else
2865 ;
2869 ;
2870 else
2877 }
2878 }
2879 \f
2880 /* ARG is a tree that is known to contain just arithmetic operations and
2881 comparisons. Evaluate the operations in the tree substituting NEW0 for
2882 any occurrence of OLD0 as an operand of a comparison and likewise for
2883 NEW1 and OLD1. */
2885 static tree
2888 {
2893 /* We can handle some of the tcc_expression cases here. */
2901 {
2916 {
2935 }
2936 /* Fall through - ??? */
2939 {
2943 /* We need to check both for exact equality and tree equality. The
2944 former will be true if the operand has a side-effect. In that
2945 case, we know the operand occurred exactly once. */
2958 }
2962 }
2963 }
2964 \f
2965 /* Return a tree for the case when the result of an expression is RESULT
2966 converted to TYPE and OMITTED was previously an operand of the expression
2967 but is now not needed (e.g., we folded OMITTED * 0).
2969 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2970 the conversion of RESULT to TYPE. */
2972 tree
2974 {
2977 /* If the resulting operand is an empty statement, just return the omitted
2978 statement casted to void. */
2980 {
2983 }
2986 {
2989 }
2993 omit_one_operand_exit:
2996 }
2998 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3000 static tree
3002 tree omitted)
3003 {
3006 /* If the resulting operand is an empty statement, just return the omitted
3007 statement casted to void. */
3009 {
3012 }
3015 {
3018 }
3022 pedantic_omit_one_operand_exit:
3025 }
3027 /* Return a tree for the case when the result of an expression is RESULT
3028 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3029 of the expression but are now not needed.
3031 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3032 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3033 evaluated before OMITTED2. Otherwise, if neither has side effects,
3034 just do the conversion of RESULT to TYPE. */
3036 tree
3039 {
3043 {
3046 }
3048 {
3051 }
3054 }
3056 \f
3057 /* Return a simplified tree node for the truth-negation of ARG. This
3058 never alters ARG itself. We assume that ARG is an operation that
3059 returns a truth value (0 or 1).
3061 FIXME: one would think we would fold the result, but it causes
3062 problems with the dominator optimizer. */
3064 tree
3066 {
3071 /* If this is a comparison, we can simply invert it, except for
3072 floating-point non-equality comparisons, in which case we just
3073 enclose a TRUTH_NOT_EXPR around what we have. */
3076 {
3079 && flag_trapping_math
3091 }
3094 {
3123 /* Here we can invert either operand. We invert the first operand
3124 unless the second operand is a TRUTH_NOT_EXPR in which case our
3125 result is the XOR of the first operand with the inside of the
3126 negation of the second operand. */
3131 else
3165 {
3176 /* A COND_EXPR may have a throw as one operand, which
3177 then has void type. Just leave void operands
3178 as they are. */
3185 }
3202 CASE_CONVERT:
3204 {
3207 }
3209 /* ... fall through ... */
3240 }
3246 }
3248 /* Return a simplified tree node for the truth-negation of ARG. This
3249 never alters ARG itself. We assume that ARG is an operation that
3250 returns a truth value (0 or 1).
3252 FIXME: one would think we would fold the result, but it causes
3253 problems with the dominator optimizer. */
3255 tree
3257 {
3258 tree tem;
3265 {
3268 }
3271 }
3273 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3274 operands are another bit-wise operation with a common input. If so,
3275 distribute the bit operations to save an operation and possibly two if
3276 constants are involved. For example, convert
3277 (A | B) & (A | C) into A | (B & C)
3278 Further simplification will occur if B and C are constants.
3280 If this optimization cannot be done, 0 will be returned. */
3282 static tree
3285 {
3286 tree common;
3296 {
3300 }
3302 {
3306 }
3308 {
3312 }
3314 {
3318 }
3319 else
3327 }
3329 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3330 with code CODE. This optimization is unsafe. */
3331 static tree
3334 {
3338 /* (A / C) +- (B / C) -> (A +- B) / C. */
3348 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3353 {
3365 }
3368 }
3369 \f
3370 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3371 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3373 static tree
3376 {
3380 {
3387 }
3402 }
3404 /* Optimize a bit-field compare.
3406 There are two cases: First is a compare against a constant and the
3407 second is a comparison of two items where the fields are at the same
3408 bit position relative to the start of a chunk (byte, halfword, word)
3409 large enough to contain it. In these cases we can avoid the shift
3410 implicit in bitfield extractions.
3412 For constants, we emit a compare of the shifted constant with the
3413 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3414 compared. For two fields at the same position, we do the ANDs with the
3415 similar mask and compare the result of the ANDs.
3417 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3418 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3419 are the left and right operands of the comparison, respectively.
3421 If the optimization described above can be done, we return the resulting
3422 tree. Otherwise we return zero. */
3424 static tree
3427 {
3436 tree mask;
3437 tree offset;
3439 /* Get all the information about the extractions being done. If the bit size
3440 if the same as the size of the underlying object, we aren't doing an
3441 extraction at all and so can do nothing. We also don't want to
3442 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3443 then will no longer be able to replace it. */
3451 {
3452 /* If this is not a constant, we can only do something if bit positions,
3453 sizes, and signedness are the same. */
3461 }
3463 /* See if we can find a mode to refer to this field. We should be able to,
3464 but fail if we can't. */
3473 /* Set signed and unsigned types of the precision of this mode for the
3474 shifts below. */
3478 /* Compute the bit position and size for the new reference and our offset
3479 within it. If the new reference is the same size as the original, we
3480 won't optimize anything, so return zero. */
3490 /* Make the mask to be used against the extracted field. */
3497 /* If not comparing with constant, just rework the comparison
3498 and return. */
3502 unsigned_type,
3505 mask),
3508 unsigned_type,
3511 mask));
3513 /* Otherwise, we are handling the constant case. See if the constant is too
3514 big for the field. Warn and return a tree of for 0 (false) if so. We do
3515 this not only for its own sake, but to avoid having to test for this
3516 error case below. If we didn't, we might generate wrong code.
3518 For unsigned fields, the constant shifted right by the field length should
3519 be all zero. For signed fields, the high-order bits should agree with
3520 the sign bit. */
3523 {
3528 {
3532 }
3533 }
3534 else
3535 {
3540 {
3544 }
3545 }
3547 /* Single-bit compares should always be against zero. */
3549 {
3552 }
3554 /* Make a new bitfield reference, shift the constant over the
3555 appropriate number of bits and mask it with the computed mask
3556 (in case this was a signed field). If we changed it, make a new one. */
3559 {
3562 }
3572 rhs);
3575 }
3576 \f
3577 /* Subroutine for fold_truthop: decode a field reference.
3579 If EXP is a comparison reference, we return the innermost reference.
3581 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3582 set to the starting bit number.
3584 If the innermost field can be completely contained in a mode-sized
3585 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3587 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3588 otherwise it is not changed.
3590 *PUNSIGNEDP is set to the signedness of the field.
3592 *PMASK is set to the mask used. This is either contained in a
3593 BIT_AND_EXPR or derived from the width of the field.
3595 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3597 Return 0 if this is not a component reference or is one that we can't
3598 do anything with. */
3600 static tree
3605 {
3609 tree unsigned_type;
3612 /* All the optimizations using this function assume integer fields.
3613 There are problems with FP fields since the type_for_size call
3614 below can fail for, e.g., XFmode. */
3618 /* We are interested in the bare arrangement of bits, so strip everything
3619 that doesn't affect the machine mode. However, record the type of the
3620 outermost expression if it may matter below. */
3627 {
3633 }
3642 /* If the number of bits in the reference is the same as the bitsize of
3643 the outer type, then the outer type gives the signedness. Otherwise
3644 (in case of a small bitfield) the signedness is unchanged. */
3648 /* Compute the mask to access the bitfield. */
3657 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3665 }
3667 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
3668 bit positions. */
3670 static int
3672 {
3675 tree tmask;
3679 return
3686 }
3688 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3689 represents the sign bit of EXP's type. If EXP represents a sign
3690 or zero extension, also test VAL against the unextended type.
3691 The return value is the (sub)expression whose sign bit is VAL,
3692 or NULL_TREE otherwise. */
3694 static tree
3696 {
3700 tree t;
3702 /* Tree EXP must have an integral type. */
3707 /* Tree VAL must be an integer constant. */
3714 {
3721 }
3722 else
3723 {
3730 }
3732 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
3733 treat VAL as if it were unsigned. */
3738 /* Handle extension from a narrower type. */
3744 }
3746 /* Subroutine for fold_truthop: determine if an operand is simple enough
3747 to be evaluated unconditionally. */
3749 static int
3751 {
3752 /* Strip any conversions that don't change the machine mode. */
3761 /* Don't regard global variables as simple. They may be
3762 allocated in ways unknown to the compiler (shared memory,
3763 #pragma weak, etc). */
3766 /* Loading a static variable is unduly expensive, but global
3767 registers aren't expensive. */
3769 }
3770 \f
3771 /* The following functions are subroutines to fold_range_test and allow it to
3772 try to change a logical combination of comparisons into a range test.
3774 For example, both
3775 X == 2 || X == 3 || X == 4 || X == 5
3776 and
3777 X >= 2 && X <= 5
3778 are converted to
3779 (unsigned) (X - 2) <= 3
3781 We describe each set of comparisons as being either inside or outside
3782 a range, using a variable named like IN_P, and then describe the
3783 range with a lower and upper bound. If one of the bounds is omitted,
3784 it represents either the highest or lowest value of the type.
3786 In the comments below, we represent a range by two numbers in brackets
3787 preceded by a "+" to designate being inside that range, or a "-" to
3788 designate being outside that range, so the condition can be inverted by
3789 flipping the prefix. An omitted bound is represented by a "-". For
3790 example, "- [-, 10]" means being outside the range starting at the lowest
3791 possible value and ending at 10, in other words, being greater than 10.
3792 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
3793 always false.
3795 We set up things so that the missing bounds are handled in a consistent
3796 manner so neither a missing bound nor "true" and "false" need to be
3797 handled using a special case. */
3799 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
3800 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
3801 and UPPER1_P are nonzero if the respective argument is an upper bound
3802 and zero for a lower. TYPE, if nonzero, is the type of the result; it
3803 must be specified for a comparison. ARG1 will be converted to ARG0's
3804 type if both are specified. */
3806 static tree
3809 {
3810 tree tem;
3814 /* If neither arg represents infinity, do the normal operation.
3815 Else, if not a comparison, return infinity. Else handle the special
3816 comparison rules. Note that most of the cases below won't occur, but
3817 are handled for consistency. */
3820 {
3825 }
3830 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
3831 for neither. In real maths, we cannot assume open ended ranges are
3832 the same. But, this is computer arithmetic, where numbers are finite.
3833 We can therefore make the transformation of any unbounded range with
3834 the value Z, Z being greater than any representable number. This permits
3835 us to treat unbounded ranges as equal. */
3839 {
3860 }
3863 }
3864 \f
3865 /* Given EXP, a logical expression, set the range it is testing into
3866 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
3867 actually being tested. *PLOW and *PHIGH will be made of the same
3868 type as the returned expression. If EXP is not a comparison, we
3869 will most likely not be returning a useful value and range. Set
3870 *STRICT_OVERFLOW_P to true if the return value is only valid
3871 because signed overflow is undefined; otherwise, do not change
3872 *STRICT_OVERFLOW_P. */
3874 tree
3877 {
3885 /* Start with simply saying "EXP != 0" and then look at the code of EXP
3886 and see if we can refine the range. Some of the cases below may not
3887 happen, but it doesn't seem worth worrying about this. We "continue"
3888 the outer loop when we've changed something; otherwise we "break"
3889 the switch, which will "break" the while. */
3895 {
3900 {
3912 }
3915 {
3922 /* We can only do something if the range is testing for zero
3923 and if the second operand is an integer constant. Note that
3924 saying something is "in" the range we make is done by
3925 complementing IN_P since it will set in the initial case of
3926 being not equal to zero; "out" is leaving it alone. */
3933 {
3954 }
3956 /* If this is an unsigned comparison, we also know that EXP is
3957 greater than or equal to zero. We base the range tests we make
3958 on that fact, so we record it here so we can parse existing
3959 range tests. We test arg0_type since often the return type
3960 of, e.g. EQ_EXPR, is boolean. */
3962 {
3966 NULL_TREE))
3971 /* If the high bound is missing, but we have a nonzero low
3972 bound, reverse the range so it goes from zero to the low bound
3973 minus 1. */
3975 {
3980 }
3981 }
3987 /* (-x) IN [a,b] -> x in [-b, -a] */
3999 /* ~ X -> -X - 1 */
4009 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4010 move a constant to the other side. */
4015 /* If EXP is signed, any overflow in the computation is undefined,
4016 so we don't worry about it so long as our computations on
4017 the bounds don't overflow. For unsigned, overflow is defined
4018 and this is exactly the right thing. */
4030 /* Check for an unsigned range which has wrapped around the maximum
4031 value thus making n_high < n_low, and normalize it. */
4033 {
4039 /* If the range is of the form +/- [ x+1, x ], we won't
4040 be able to normalize it. But then, it represents the
4041 whole range or the empty set, so make it
4042 +/- [ -, - ]. */
4046 else
4048 }
4049 else
4073 /* If we're converting arg0 from an unsigned type, to exp,
4074 a signed type, we will be doing the comparison as unsigned.
4075 The tests above have already verified that LOW and HIGH
4076 are both positive.
4078 So we have to ensure that we will handle large unsigned
4079 values the same way that the current signed bounds treat
4080 negative values. */
4083 {
4084 tree high_positive;
4085 tree equiv_type;
4086 /* For fixed-point modes, we need to pass the saturating flag
4087 as the 2nd parameter. */
4092 else
4096 /* A range without an upper bound is, naturally, unbounded.
4097 Since convert would have cropped a very large value, use
4098 the max value for the destination type. */
4099 high_positive
4106 high_positive),
4109 /* If the low bound is specified, "and" the range with the
4110 range for which the original unsigned value will be
4111 positive. */
4113 {
4117 integer_zero_node),
4118 high_positive))
4122 }
4123 else
4124 {
4125 /* Otherwise, "or" the range with the range of the input
4126 that will be interpreted as negative. */
4130 integer_zero_node),
4131 high_positive))
4135 }
4136 }
4144 }
4147 }
4149 /* If EXP is a constant, we can evaluate whether this is true or false. */
4151 {
4158 }
4162 }
4163 \f
4164 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4165 type, TYPE, return an expression to test if EXP is in (or out of, depending
4166 on IN_P) the range. Return 0 if the test couldn't be created. */
4168 tree
4171 {
4174 #ifdef HAVE_canonicalize_funcptr_for_compare
4175 /* Disable this optimization for function pointer expressions
4176 on targets that require function pointer canonicalization. */
4181 #endif
4184 {
4190 }
4208 {
4210 {
4214 }
4216 }
4218 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4220 {
4222 HOST_WIDE_INT hi;
4227 {
4230 }
4231 else
4232 {
4235 }
4238 {
4240 {
4243 etype
4245 else
4248 }
4251 }
4252 }
4254 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4255 This requires wrap-around arithmetics for the type of the expression.
4256 First make sure that arithmetics in this type is valid, then make sure
4257 that it wraps around. */
4263 {
4266 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4267 for the type in question, as we rely on this here. */
4277 else
4279 }
4289 {
4291 {
4298 }
4300 }
4308 }
4309 \f
4310 /* Return the predecessor of VAL in its type, handling the infinite case. */
4312 static tree
4314 {
4320 else
4322 }
4324 /* Return the successor of VAL in its type, handling the infinite case. */
4326 static tree
4328 {
4334 else
4336 }
4338 /* Given two ranges, see if we can merge them into one. Return 1 if we
4339 can, 0 if we can't. Set the output range into the specified parameters. */
4341 bool
4344 {
4348 tree tem;
4358 /* Make range 0 be the range that starts first, or ends last if they
4359 start at the same value. Swap them if it isn't. */
4362 || (lowequal
4365 {
4369 }
4371 /* Now flag two cases, whether the ranges are disjoint or whether the
4372 second range is totally subsumed in the first. Note that the tests
4373 below are simplified by the ones above. */
4379 /* We now have four cases, depending on whether we are including or
4380 excluding the two ranges. */
4382 {
4383 /* If they don't overlap, the result is false. If the second range
4384 is a subset it is the result. Otherwise, the range is from the start
4385 of the second to the end of the first. */
4390 else
4392 }
4395 {
4396 /* If they don't overlap, the result is the first range. If they are
4397 equal, the result is false. If the second range is a subset of the
4398 first, and the ranges begin at the same place, we go from just after
4399 the end of the second range to the end of the first. If the second
4400 range is not a subset of the first, or if it is a subset and both
4401 ranges end at the same place, the range starts at the start of the
4402 first range and ends just before the second range.
4403 Otherwise, we can't describe this as a single range. */
4409 {
4414 {
4415 /* We are in the weird situation where high0 > high1 but
4416 high1 has no successor. Punt. */
4418 }
4419 }
4421 {
4426 {
4427 /* low0 < low1 but low1 has no predecessor. Punt. */
4429 }
4430 }
4431 else
4433 }
4436 {
4437 /* If they don't overlap, the result is the second range. If the second
4438 is a subset of the first, the result is false. Otherwise,
4439 the range starts just after the first range and ends at the
4440 end of the second. */
4445 else
4446 {
4451 {
4452 /* high1 > high0 but high0 has no successor. Punt. */
4454 }
4455 }
4456 }
4458 else
4459 {
4460 /* The case where we are excluding both ranges. Here the complex case
4461 is if they don't overlap. In that case, the only time we have a
4462 range is if they are adjacent. If the second is a subset of the
4463 first, the result is the first. Otherwise, the range to exclude
4464 starts at the beginning of the first range and ends at the end of the
4465 second. */
4467 {
4472 else
4473 {
4474 /* Canonicalize - [min, x] into - [-, x]. */
4477 {
4482 /* FALLTHROUGH */
4495 }
4497 /* Canonicalize - [x, max] into - [x, -]. */
4500 {
4505 /* FALLTHROUGH */
4520 }
4522 /* The ranges might be also adjacent between the maximum and
4523 minimum values of the given type. For
4524 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4525 return + [x + 1, y - 1]. */
4527 {
4534 }
4535 else
4537 }
4538 }
4541 else
4543 }
4547 }
4548 \f
4550 /* Subroutine of fold, looking inside expressions of the form
4551 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4552 of the COND_EXPR. This function is being used also to optimize
4553 A op B ? C : A, by reversing the comparison first.
4555 Return a folded expression whose code is not a COND_EXPR
4556 anymore, or NULL_TREE if no folding opportunity is found. */
4558 static tree
4561 {
4566 tree tem;
4571 /* If we have A op 0 ? A : -A, consider applying the following
4572 transformations:
4574 A == 0? A : -A same as -A
4575 A != 0? A : -A same as A
4576 A >= 0? A : -A same as abs (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)
4581 None of these transformations work for modes with signed
4582 zeros. If A is +/-0, the first two transformations will
4583 change the sign of the result (from +0 to -0, or vice
4584 versa). The last four will fix the sign of the result,
4585 even though the original expressions could be positive or
4586 negative, depending on the sign of A.
4588 Note that all these transformations are correct if A is
4589 NaN, since the two alternatives (A and -A) are also NaNs. */
4596 /* In the case that A is of the form X-Y, '-A' (arg2) may
4597 have already been folded to Y-X, check for that. */
4605 {
4619 /* Fall through. */
4641 }
4643 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4644 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4645 both transformations are correct when A is NaN: A != 0
4646 is then true, and A == 0 is false. */
4650 {
4655 }
4657 /* Try some transformations of A op B ? A : B.
4659 A == B? A : B same as B
4660 A != B? A : B same as A
4661 A >= B? A : B same as max (A, B)
4662 A > B? A : B same as max (B, A)
4663 A <= B? A : B same as min (A, B)
4664 A < B? A : B same as min (B, A)
4666 As above, these transformations don't work in the presence
4667 of signed zeros. For example, if A and B are zeros of
4668 opposite sign, the first two transformations will change
4669 the sign of the result. In the last four, the original
4670 expressions give different results for (A=+0, B=-0) and
4671 (A=-0, B=+0), but the transformed expressions do not.
4673 The first two transformations are correct if either A or B
4674 is a NaN. In the first transformation, the condition will
4675 be false, and B will indeed be chosen. In the case of the
4676 second transformation, the condition A != B will be true,
4677 and A will be chosen.
4679 The conversions to max() and min() are not correct if B is
4680 a number and A is not. The conditions in the original
4681 expressions will be false, so all four give B. The min()
4682 and max() versions would give a NaN instead. */
4685 /* Avoid these transformations if the COND_EXPR may be used
4686 as an lvalue in the C++ front-end. PR c++/19199. */
4687 && (in_gimple_form
4692 {
4697 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4699 {
4703 }
4706 {
4715 /* In C++ a ?: expression can be an lvalue, so put the
4716 operand which will be used if they are equal first
4717 so that we can convert this back to the
4718 corresponding COND_EXPR. */
4720 {
4729 }
4736 {
4745 }
4760 }
4761 }
4763 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
4764 we might still be able to simplify this. For example,
4765 if C1 is one less or one more than C2, this might have started
4766 out as a MIN or MAX and been transformed by this function.
4767 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
4773 {
4777 /* We can replace A with C1 in this case. */
4782 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
4783 MIN_EXPR, to preserve the signedness of the comparison. */
4785 OEP_ONLY_CONST)
4789 OEP_ONLY_CONST))
4790 {
4793 arg2));
4796 }
4800 /* If C1 is C2 - 1, this is min(A, C2), with the same care
4801 as above. */
4803 OEP_ONLY_CONST)
4807 OEP_ONLY_CONST))
4808 {
4811 arg2));
4814 }
4818 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
4819 MAX_EXPR, to preserve the signedness of the comparison. */
4821 OEP_ONLY_CONST)
4825 OEP_ONLY_CONST))
4826 {
4829 arg2));
4831 }
4835 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
4837 OEP_ONLY_CONST)
4841 OEP_ONLY_CONST))
4842 {
4845 arg2));
4847 }
4853 }
4856 }
4859 \f
4860 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
4861 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
4862 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
4863 false) >= 2)
4864 #endif
4866 /* EXP is some logical combination of boolean tests. See if we can
4867 merge it into some range test. Return the new tree if so. */
4869 static tree
4872 {
4880 tree tem;
4884 /* If this is an OR operation, invert both sides; we will invert
4885 again at the end. */
4889 /* If both expressions are the same, if we can merge the ranges, and we
4890 can build the range test, return it or it inverted. If one of the
4891 ranges is always true or always false, consider it to be the same
4892 expression as the other. */
4900 {
4904 }
4906 /* On machines where the branch cost is expensive, if this is a
4907 short-circuited branch and the underlying object on both sides
4908 is the same, make a non-short-circuit operation. */
4914 {
4915 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
4916 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
4917 which cases we can't do this. */
4919 {
4925 }
4929 {
4938 {
4941 WARN_STRICT_OVERFLOW_COMPARISON);
4947 }
4948 }
4949 }
4952 }
4953 \f
4954 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
4955 bit value. Arrange things so the extra bits will be set to zero if and
4956 only if C is signed-extended to its full width. If MASK is nonzero,
4957 it is an INTEGER_CST that should be AND'ed with the extra bits. */
4959 static tree
4961 {
4964 tree temp;
4969 /* We work by getting just the sign bit into the low-order bit, then
4970 into the high-order bit, then sign-extend. We then XOR that value
4971 with C. */
4975 /* We must use a signed type in order to get an arithmetic right shift.
4976 However, we must also avoid introducing accidental overflows, so that
4977 a subsequent call to integer_zerop will work. Hence we must
4978 do the type conversion here. At this point, the constant is either
4979 zero or one, and the conversion to a signed type can never overflow.
4980 We could get an overflow if this conversion is done anywhere else. */
4990 /* If necessary, convert the type back to match the type of C. */
4996 }
4997 \f
4998 /* For an expression that has the form
4999 (A && B) || ~B
5000 or
5001 (A || B) && ~B,
5002 we can drop one of the inner expressions and simplify to
5003 A || ~B
5004 or
5005 A && ~B
5006 LOC is the location of the resulting expression. OP is the inner
5007 logical operation; the left-hand side in the examples above, while CMPOP
5008 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5009 removing a condition that guards another, as in
5010 (A != NULL && A->...) || A == NULL
5011 which we must not transform. If RHS_ONLY is true, only eliminate the
5012 right-most operand of the inner logical operation. */
5014 static tree
5017 {
5035 {
5038 {
5041 }
5042 }
5044 {
5047 {
5050 }
5051 }
5066 }
5068 /* Find ways of folding logical expressions of LHS and RHS:
5069 Try to merge two comparisons to the same innermost item.
5070 Look for range tests like "ch >= '0' && ch <= '9'".
5071 Look for combinations of simple terms on machines with expensive branches
5072 and evaluate the RHS unconditionally.
5074 For example, if we have p->a == 2 && p->b == 4 and we can make an
5075 object large enough to span both A and B, we can do this with a comparison
5076 against the object ANDed with the a mask.
5078 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5079 operations to do this with one comparison.
5081 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5082 function and the one above.
5084 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5085 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5087 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5088 two operands.
5090 We return the simplified tree or 0 if no optimization is possible. */
5092 static tree
5095 {
5096 /* If this is the "or" of two comparisons, we can do something if
5097 the comparisons are NE_EXPR. If this is the "and", we can do something
5098 if the comparisons are EQ_EXPR. I.e.,
5099 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5101 WANTED_CODE is this operation code. For single bit fields, we can
5102 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5103 comparison for one-bit fields. */
5125 /* Start by getting the comparison codes. Fail if anything is volatile.
5126 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5127 it were surrounded with a NE_EXPR. */
5136 {
5140 }
5143 {
5147 }
5158 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5161 {
5162 tree result;
5165 {
5170 }
5173 {
5179 }
5180 }
5185 /* If the RHS can be evaluated unconditionally and its operands are
5186 simple, it wins to evaluate the RHS unconditionally on machines
5187 with expensive branches. In this case, this isn't a comparison
5188 that can be merged. Avoid doing this if the RHS is a floating-point
5189 comparison since those can trap. */
5196 {
5197 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5203 {
5209 }
5211 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5217 {
5223 }
5226 {
5228 {
5231 }
5233 }
5234 }
5236 /* See if the comparisons can be merged. Then get all the parameters for
5237 each side. */
5261 /* It must be true that the inner operation on the lhs of each
5262 comparison must be the same if we are to be able to do anything.
5263 Then see if we have constants. If not, the same must be true for
5264 the rhs's. */
5275 else
5278 /* If either comparison code is not correct for our logical operation,
5279 fail. However, we can convert a one-bit comparison against zero into
5280 the opposite comparison against that bit being set in the field. */
5284 {
5286 {
5287 /* Make the left operand unsigned, since we are only interested
5288 in the value of one bit. Otherwise we are doing the wrong
5289 thing below. */
5292 }
5293 else
5295 }
5297 /* This is analogous to the code for l_const above. */
5299 {
5301 {
5304 }
5305 else
5307 }
5309 /* See if we can find a mode that contains both fields being compared on
5310 the left. If we can't, fail. Otherwise, update all constants and masks
5311 to be relative to a field of that size. */
5316 volatilep);
5326 {
5329 }
5337 {
5345 {
5349 }
5350 }
5352 {
5360 {
5364 }
5365 }
5367 /* If the right sides are not constant, do the same for it. Also,
5368 disallow this optimization if a size or signedness mismatch occurs
5369 between the left and right sides. */
5371 {
5374 /* Make sure the two fields on the right
5375 correspond to the left without being swapped. */
5383 volatilep);
5393 {
5396 }
5405 /* Make a mask that corresponds to both fields being compared.
5406 Do this for both items being compared. If the operands are the
5407 same size and the bits being compared are in the same position
5408 then we can do this by masking both and comparing the masked
5409 results. */
5413 {
5426 }
5428 /* There is still another way we can do something: If both pairs of
5429 fields being compared are adjacent, we may be able to make a wider
5430 field containing them both.
5432 Note that we still must mask the lhs/rhs expressions. Furthermore,
5433 the mask must be shifted to account for the shift done by
5434 make_bit_field_ref. */
5439 {
5440 tree type;
5454 /* Convert to the smaller type before masking out unwanted bits. */
5457 {
5459 {
5463 }
5465 {
5469 }
5470 }
5480 }
5483 }
5485 /* Handle the case of comparisons with constants. If there is something in
5486 common between the masks, those bits of the constants must be the same.
5487 If not, the condition is always false. Test for this to avoid generating
5488 incorrect code below. */
5493 {
5495 {
5498 }
5499 else
5500 {
5503 }
5504 }
5506 /* Construct the expression we will return. First get the component
5507 reference we will make. Unless the mask is all ones the width of
5508 that field, perform the mask operation. Then compare with the
5509 merged constant. */
5515 {
5518 }
5523 fold_truthop_exit:
5526 }
5527 \f
5528 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5529 constant. */
5531 static tree
5534 {
5537 tree comp_const;
5538 tree minmax_const;
5540 tree inner;
5551 /* If something does not permit us to optimize, return the original tree. */
5559 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5560 and GT_EXPR, doing the rest with recursive calls using logical
5561 simplifications. */
5563 {
5565 {
5566 tree tem
5573 }
5576 return
5578 optimize_minmax_comparison
5580 optimize_minmax_comparison
5585 /* MAX (X, 0) == 0 -> X <= 0 */
5589 /* MAX (X, 0) == 5 -> X == 5 */
5593 /* MAX (X, 0) == -1 -> false */
5597 /* MIN (X, 0) == 0 -> X >= 0 */
5601 /* MIN (X, 0) == 5 -> false */
5604 else
5605 /* MIN (X, 0) == -1 -> X == -1 */
5610 /* MAX (X, 0) > 0 -> X > 0
5611 MAX (X, 0) > 5 -> X > 5 */
5615 /* MAX (X, 0) > -1 -> true */
5619 /* MIN (X, 0) > 0 -> false
5620 MIN (X, 0) > 5 -> false */
5623 else
5624 /* MIN (X, 0) > -1 -> X > -1 */
5629 }
5630 }
5631 \f
5632 /* T is an integer expression that is being multiplied, divided, or taken a
5633 modulus (CODE says which and what kind of divide or modulus) by a
5634 constant C. See if we can eliminate that operation by folding it with
5635 other operations already in T. WIDE_TYPE, if non-null, is a type that
5636 should be used for the computation if wider than our type.
5638 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5639 (X * 2) + (Y * 4). We must, however, be assured that either the original
5640 expression would not overflow or that overflow is undefined for the type
5641 in the language in question.
5643 If we return a non-null expression, it is an equivalent form of the
5644 original computation, but need not be in the original type.
5646 We set *STRICT_OVERFLOW_P to true if the return values depends on
5647 signed overflow being undefined. Otherwise we do not change
5648 *STRICT_OVERFLOW_P. */
5650 static tree
5653 {
5654 /* To avoid exponential search depth, refuse to allow recursion past
5655 three levels. Beyond that (1) it's highly unlikely that we'll find
5656 something interesting and (2) we've probably processed it before
5657 when we built the inner expression. */
5660 tree ret;
5665 depth++;
5667 depth--;
5670 }
5672 static tree
5675 {
5686 /* Don't deal with constants of zero here; they confuse the code below. */
5696 /* Note that we need not handle conditional operations here since fold
5697 already handles those cases. So just do arithmetic here. */
5699 {
5701 /* For a constant, we can always simplify if we are a multiply
5702 or (for divide and modulus) if it is a multiple of our constant. */
5710 /* If op0 is an expression ... */
5716 /* ... and has wrapping overflow, and its type is smaller
5717 than ctype, then we cannot pass through as widening. */
5723 /* ... or this is a truncation (t is narrower than op0),
5724 then we cannot pass through this narrowing. */
5727 /* ... or signedness changes for division or modulus,
5728 then we cannot pass through this conversion. */
5732 /* ... or has undefined overflow while the converted to
5733 type has not, we cannot do the operation in the inner type
5734 as that would introduce undefined overflow. */
5739 /* Pass the constant down and see if we can make a simplification. If
5740 we can, replace this expression with the inner simplification for
5741 possible later conversion to our or some other type. */
5746 code == MULT_EXPR
5748 strict_overflow_p))))
5753 /* If widening the type changes it from signed to unsigned, then we
5754 must avoid building ABS_EXPR itself as unsigned. */
5756 {
5760 {
5763 }
5765 }
5766 /* If the constant is negative, we cannot simplify this. */
5769 /* FALLTHROUGH */
5777 /* If widening the type changes the signedness, then we can't perform
5778 this optimization as that changes the result. */
5782 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5788 {
5795 }
5799 /* If the second operand is constant, this is a multiplication
5800 or floor division, by a power of two, so we can treat it that
5801 way unless the multiplier or divisor overflows. Signed
5802 left-shift overflow is implementation-defined rather than
5803 undefined in C90, so do not convert signed left shift into
5804 multiplication. */
5807 /* const_binop may not detect overflow correctly,
5808 so check for it explicitly here. */
5813 size_one_node,
5818 ctype,
5820 t1),
5825 /* See if we can eliminate the operation on both sides. If we can, we
5826 can return a new PLUS or MINUS. If we can't, the only remaining
5827 cases where we can do anything are if the second operand is a
5828 constant. */
5834 /* If not multiplication, we can only do this if both operands
5835 are divisible by c. */
5838 {
5843 }
5845 /* If this was a subtraction, negate OP1 and set it to be an addition.
5846 This simplifies the logic below. */
5848 {
5850 /* If OP1 was not easily negatable, the constant may be OP0. */
5852 {
5859 }
5860 }
5865 /* If either OP1 or C are negative, this optimization is not safe for
5866 some of the division and remainder types while for others we need
5867 to change the code. */
5869 {
5877 }
5879 /* If it's a multiply or a division/modulus operation of a multiple
5880 of our constant, do the operation and verify it doesn't overflow. */
5883 {
5886 /* We allow the constant to overflow with wrapping semantics. */
5890 }
5891 else
5894 /* If we have an unsigned type is not a sizetype, we cannot widen
5895 the operation since it will change the result if the original
5896 computation overflowed. */
5902 /* If we were able to eliminate our operation from the first side,
5903 apply our operation to the second side and reform the PLUS. */
5907 /* The last case is if we are a multiply. In that case, we can
5908 apply the distributive law to commute the multiply and addition
5909 if the multiplication of the constants doesn't overflow. */
5915 op1);
5920 /* We have a special case here if we are doing something like
5921 (C * 8) % 4 since we know that's zero. */
5924 /* If the multiplication can overflow we cannot optimize this.
5925 ??? Until we can properly mark individual operations as
5926 not overflowing we need to treat sizetype special here as
5927 stor-layout relies on this opimization to make
5928 DECL_FIELD_BIT_OFFSET always a constant. */
5934 {
5937 }
5939 /* ... fall through ... */
5943 /* If we can extract our operation from the LHS, do so and return a
5944 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5945 do something only if the second operand is a constant. */
5959 /* If these are the same operation types, we can associate them
5960 assuming no overflow. */
5973 /* If these operations "cancel" each other, we have the main
5974 optimizations of this pass, which occur when either constant is a
5975 multiple of the other, in which case we replace this with either an
5976 operation or CODE or TCODE.
5978 If we have an unsigned type that is not a sizetype, we cannot do
5979 this since it will change the result if the original computation
5980 overflowed. */
5988 {
5990 {
5997 }
5999 {
6006 }
6007 }
6012 }
6015 }
6016 \f
6017 /* Return a node which has the indicated constant VALUE (either 0 or
6018 1), and is of the indicated TYPE. */
6020 tree
6022 {
6027 else
6029 }
6032 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6033 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6034 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6035 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6036 COND is the first argument to CODE; otherwise (as in the example
6037 given here), it is the second argument. TYPE is the type of the
6038 original expression. Return NULL_TREE if no simplification is
6039 possible. */
6041 static tree
6046 {
6054 {
6058 /* If this operand throws an expression, then it does not make
6059 sense to try to perform a logical or arithmetic operation
6060 involving it. */
6065 }
6066 else
6067 {
6072 }
6074 /* This transformation is only worthwhile if we don't have to wrap ARG
6075 in a SAVE_EXPR and the operation can be simplified on at least one
6076 of the branches once its pushed inside the COND_EXPR. */
6084 {
6088 else
6090 }
6092 {
6096 else
6098 }
6100 /* Check that we have simplified at least one of the branches. */
6105 }
6107 \f
6108 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6110 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6111 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6112 ADDEND is the same as X.
6114 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6115 and finite. The problematic cases are when X is zero, and its mode
6116 has signed zeros. In the case of rounding towards -infinity,
6117 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6118 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6120 bool
6122 {
6126 /* Don't allow the fold with -fsignaling-nans. */
6130 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6134 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6139 /* The mode has signed zeros, and we have to honor their sign.
6140 In this situation, there is only one case we can return true for.
6141 X - 0 is the same as X unless rounding towards -infinity is
6142 supported. */
6144 }
6146 /* Subroutine of fold() that checks comparisons of built-in math
6147 functions against real constants.
6149 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6150 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6151 is the type of the result and ARG0 and ARG1 are the operands of the
6152 comparison. ARG1 must be a TREE_REAL_CST.
6154 The function returns the constant folded tree if a simplification
6155 can be made, and NULL_TREE otherwise. */
6157 static tree
6161 {
6162 REAL_VALUE_TYPE c;
6165 {
6171 {
6172 /* sqrt(x) < y is always false, if y is negative. */
6176 /* sqrt(x) > y is always true, if y is negative and we
6177 don't care about NaNs, i.e. negative values of x. */
6181 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6184 }
6186 {
6187 REAL_VALUE_TYPE c2;
6193 {
6194 /* sqrt(x) > y is x == +Inf, when y is very large. */
6199 /* sqrt(x) > y is always false, when y is very large
6200 and we don't care about infinities. */
6202 }
6204 /* sqrt(x) > c is the same as x > c*c. */
6207 }
6209 {
6210 REAL_VALUE_TYPE c2;
6216 {
6217 /* sqrt(x) < y is always true, when y is a very large
6218 value and we don't care about NaNs or Infinities. */
6222 /* sqrt(x) < y is x != +Inf when y is very large and we
6223 don't care about NaNs. */
6228 /* sqrt(x) < y is x >= 0 when y is very large and we
6229 don't care about Infinities. */
6234 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6243 dconst0)),
6246 c2)));
6247 }
6249 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6254 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6257 {
6262 dconst0)),
6265 c2)));
6266 }
6267 }
6268 }
6271 }
6273 /* Subroutine of fold() that optimizes comparisons against Infinities,
6274 either +Inf or -Inf.
6276 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6277 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6278 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6280 The function returns the constant folded tree if a simplification
6281 can be made, and NULL_TREE otherwise. */
6283 static tree
6286 {
6288 REAL_VALUE_TYPE max;
6289 tree temp;
6294 /* For negative infinity swap the sense of the comparison. */
6300 {
6302 /* x > +Inf is always false, if with ignore sNANs. */
6308 /* x <= +Inf is always true, if we don't case about NaNs. */
6312 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6315 {
6318 }
6323 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6329 /* x < +Inf is always equal to x <= DBL_MAX. */
6335 /* x != +Inf is always equal to !(x > DBL_MAX). */
6347 }
6350 }
6352 /* Subroutine of fold() that optimizes comparisons of a division by
6353 a nonzero integer constant against an integer constant, i.e.
6354 X/C1 op C2.
6356 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6357 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6358 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6360 The function returns the constant folded tree if a simplification
6361 can be made, and NULL_TREE otherwise. */
6363 static tree
6366 {
6371 HOST_WIDE_INT hpart;
6376 /* We have to do this the hard way to detect unsigned overflow.
6377 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6388 {
6393 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6401 }
6403 {
6407 {
6426 }
6427 }
6428 else
6429 {
6430 /* A negative divisor reverses the relational operators. */
6436 {
6455 }
6456 }
6459 {
6480 {
6483 }
6488 {
6491 }
6496 {
6499 }
6504 {
6507 }
6512 }
6515 }
6518 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6519 equality/inequality test, then return a simplified form of the test
6520 using a sign testing. Otherwise return NULL. TYPE is the desired
6521 result type. */
6523 static tree
6526 tree result_type)
6527 {
6528 /* If this is testing a single bit, we can optimize the test. */
6532 {
6533 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6534 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6538 /* This is only a win if casting to a signed type is cheap,
6539 i.e. when arg00's type is not a partial mode. */
6542 {
6545 result_type,
6548 }
6549 }
6552 }
6554 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6555 equality/inequality test, then return a simplified form of
6556 the test using shifts and logical operations. Otherwise return
6557 NULL. TYPE is the desired result type. */
6559 tree
6562 {
6563 /* If this is testing a single bit, we can optimize the test. */
6567 {
6576 /* First, see if we can fold the single bit test into a sign-bit
6577 test. */
6579 result_type);
6583 /* Otherwise we have (A & C) != 0 where C is a single bit,
6584 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6585 Similarly for (A & C) == 0. */
6587 /* If INNER is a right shift of a constant and it plus BITNUM does
6588 not overflow, adjust BITNUM and INNER. */
6595 {
6598 }
6600 /* If we are going to be able to omit the AND below, we must do our
6601 operations as unsigned. If we must use the AND, we have a choice.
6602 Normally unsigned is faster, but for some machines signed is. */
6603 #ifdef LOAD_EXTEND_OP
6606 #else
6608 #endif
6624 /* Put the AND last so it can combine with more things. */
6627 /* Make sure to return the proper type. */
6631 }
6633 }
6635 /* Check whether we are allowed to reorder operands arg0 and arg1,
6636 such that the evaluation of arg1 occurs before arg0. */
6638 static bool
6640 {
6647 }
6649 /* Test whether it is preferable two swap two operands, ARG0 and
6650 ARG1, for example because ARG0 is an integer constant and ARG1
6651 isn't. If REORDER is true, only recommend swapping if we can
6652 evaluate the operands in reverse order. */
6654 bool
6656 {
6692 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6693 for commutative and comparison operators. Ensuring a canonical
6694 form allows the optimizers to find additional redundancies without
6695 having to explicitly check for both orderings. */
6701 /* Put SSA_NAMEs last. */
6707 /* Put variables last. */
6714 }
6716 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6717 ARG0 is extended to a wider type. */
6719 static tree
6722 {
6724 tree arg1_unw;
6733 #ifdef HAVE_canonicalize_funcptr_for_compare
6734 /* Disable this optimization if we're casting a function pointer
6735 type on targets that require function pointer canonicalization. */
6740 #endif
6747 /* If possible, express the comparison in the shorter mode. */
6767 /* If we are comparing with the integer that does not fit into the range
6768 of the shorter type, the result is known. */
6779 {
6806 }
6809 }
6811 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6812 ARG0 just the signedness is changed. */
6814 static tree
6817 {
6818 tree arg0_inner;
6828 #ifdef HAVE_canonicalize_funcptr_for_compare
6829 /* Disable this optimization if we're casting a function pointer
6830 type on targets that require function pointer canonicalization. */
6835 #endif
6855 else
6859 }
6861 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6862 step of the array. Reconstructs s and delta in the case of s *
6863 delta being an integer constant (and thus already folded). ADDR is
6864 the address. MULT is the multiplicative expression. If the
6865 function succeeds, the new address expression is returned.
6866 Otherwise NULL_TREE is returned. LOC is the location of the
6867 resulting expression. */
6869 static tree
6871 {
6875 tree itype;
6878 /* Strip the nops that might be added when converting op1 to sizetype. */
6881 /* Canonicalize op1 into a possibly non-constant delta
6882 and an INTEGER_CST s. */
6884 {
6891 {
6894 }
6896 {
6899 }
6900 else
6902 }
6904 {
6907 }
6908 else
6909 {
6910 /* Simulate we are delta * 1. */
6913 }
6916 {
6918 {
6919 tree domain;
6921 /* Remember if this was a multi-dimensional array. */
6935 {
6938 }
6939 else
6940 {
6941 /* Try if delta is a multiple of step. */
6946 }
6948 /* Only fold here if we can verify we do not overflow one
6949 dimension of a multi-dimensional array. */
6951 {
6952 tree tmp;
6967 }
6970 }
6971 else
6976 }
6978 /* We found the suitable array reference. So copy everything up to it,
6979 and replace the index. */
6987 {
6991 }
6999 }
7002 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7003 means A >= Y && A != MAX, but in this case we know that
7004 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7006 static tree
7008 {
7015 else
7024 {
7027 }
7029 {
7032 }
7033 else
7040 {
7041 /* Convert the pointer types into integer before taking the difference. */
7045 }
7046 else
7053 }
7055 /* Fold a sum or difference of at least one multiplication.
7056 Returns the folded tree or NULL if no simplification could be made. */
7058 static tree
7061 {
7065 /* (A * C) +- (B * C) -> (A+-B) * C.
7066 (A * C) +- A -> A * (C+-1).
7067 We are most concerned about the case where C is a constant,
7068 but other combinations show up during loop reduction. Since
7069 it is not difficult, try all four possibilities. */
7072 {
7075 }
7077 {
7080 }
7081 else
7082 {
7083 /* We cannot generate constant 1 for fract. */
7088 }
7090 {
7093 }
7095 {
7097 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7098 the purpose of this canonicalization. */
7102 {
7105 }
7106 else
7108 }
7109 else
7110 {
7111 /* We cannot generate constant 1 for fract. */
7116 }
7128 /* No identical multiplicands; see if we can find a common
7129 power-of-two factor in non-power-of-two multiplies. This
7130 can help in multi-dimensional array access. */
7133 {
7136 tree maybe_same;
7140 /* Move min of absolute values to int11. */
7143 {
7148 }
7149 else
7153 /* The remainder should not be a constant, otherwise we
7154 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7155 increased the number of multiplications necessary. */
7157 {
7165 }
7166 }
7176 }
7178 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7179 specified by EXPR into the buffer PTR of length LEN bytes.
7180 Return the number of bytes placed in the buffer, or zero
7181 upon failure. */
7183 static int
7185 {
7196 {
7200 else
7205 {
7212 else
7214 }
7215 else
7218 }
7220 }
7223 /* Subroutine of native_encode_expr. Encode the REAL_CST
7224 specified by EXPR into the buffer PTR of length LEN bytes.
7225 Return the number of bytes placed in the buffer, or zero
7226 upon failure. */
7228 static int
7230 {
7236 /* There are always 32 bits in each long, no matter the size of
7237 the hosts long. We handle floating point representations with
7238 up to 192 bits. */
7249 {
7254 {
7261 else
7263 }
7264 else
7267 }
7269 }
7271 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7272 specified by EXPR into the buffer PTR of length LEN bytes.
7273 Return the number of bytes placed in the buffer, or zero
7274 upon failure. */
7276 static int
7278 {
7280 tree part;
7291 }
7294 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7295 specified by EXPR into the buffer PTR of length LEN bytes.
7296 Return the number of bytes placed in the buffer, or zero
7297 upon failure. */
7299 static int
7301 {
7311 {
7313 {
7316 }
7317 else
7321 {
7324 }
7325 else
7326 {
7330 }
7332 }
7334 }
7337 /* Subroutine of native_encode_expr. Encode the STRING_CST
7338 specified by EXPR into the buffer PTR of length LEN bytes.
7339 Return the number of bytes placed in the buffer, or zero
7340 upon failure. */
7342 static int
7344 {
7346 HOST_WIDE_INT total_bytes;
7357 {
7361 }
7362 else
7365 }
7368 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7369 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7370 buffer PTR of length LEN bytes. Return the number of bytes
7371 placed in the buffer, or zero upon failure. */
7373 int
7375 {
7377 {
7395 }
7396 }
7399 /* Subroutine of native_interpret_expr. Interpret the contents of
7400 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7401 If the buffer cannot be interpreted, return NULL_TREE. */
7403 static tree
7405 {
7409 double_int result;
7420 {
7423 {
7430 else
7432 }
7433 else
7439 else
7442 }
7445 }
7448 /* Subroutine of native_interpret_expr. Interpret the contents of
7449 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7450 If the buffer cannot be interpreted, return NULL_TREE. */
7452 static tree
7454 {
7459 /* There are always 32 bits in each long, no matter the size of
7460 the hosts long. We handle floating point representations with
7461 up to 192 bits. */
7462 REAL_VALUE_TYPE r;
7473 {
7476 {
7483 else
7485 }
7486 else
7491 }
7495 }
7498 /* Subroutine of native_interpret_expr. Interpret the contents of
7499 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7500 If the buffer cannot be interpreted, return NULL_TREE. */
7502 static tree
7504 {
7519 }
7522 /* Subroutine of native_interpret_expr. Interpret the contents of
7523 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7524 If the buffer cannot be interpreted, return NULL_TREE. */
7526 static tree
7528 {
7540 {
7545 }
7547 }
7550 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7551 the buffer PTR of length LEN as a constant of type TYPE. For
7552 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7553 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7554 return NULL_TREE. */
7556 tree
7558 {
7560 {
7577 }
7578 }
7581 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7582 TYPE at compile-time. If we're unable to perform the conversion
7583 return NULL_TREE. */
7585 static tree
7587 {
7588 /* We support up to 512-bit values (for V8DFmode). */
7592 /* Check that the host and target are sane. */
7601 }
7603 /* Build an expression for the address of T. Folds away INDIRECT_REF
7604 to avoid confusing the gimplify process. */
7606 tree
7608 {
7609 /* The size of the object is not relevant when talking about its address. */
7613 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7616 {
7620 {
7623 }
7624 }
7626 {
7631 }
7632 else
7633 {
7636 }
7639 }
7641 /* Build an expression for the address of T. */
7643 tree
7645 {
7649 }
7651 /* Fold a unary expression of code CODE and type TYPE with operand
7652 OP0. Return the folded expression if folding is successful.
7653 Otherwise, return NULL_TREE. */
7655 tree
7657 {
7658 tree tem;
7659 tree arg0;
7667 {
7670 {
7671 /* Don't use STRIP_NOPS, because signedness of argument type
7672 matters. */
7674 }
7675 else
7676 {
7677 /* Strip any conversions that don't change the mode. This
7678 is safe for every expression, except for a comparison
7679 expression because its signedness is derived from its
7680 operands.
7682 Note that this is done as an internal manipulation within
7683 the constant folder, in order to find the simplest
7684 representation of the arguments so that their form can be
7685 studied. In any cases, the appropriate type conversions
7686 should be put back in the tree that will get out of the
7687 constant folder. */
7689 }
7690 }
7693 {
7700 {
7714 /* If this was a conversion, and all we did was to move into
7715 inside the COND_EXPR, bring it back out. But leave it if
7716 it is a conversion from integer to integer and the
7717 result precision is no wider than a word since such a
7718 conversion is cheap and may be optimized away by combine,
7719 while it couldn't if it were outside the COND_EXPR. Then return
7720 so we don't get into an infinite recursion loop taking the
7721 conversion out and then back in. */
7733 && (INTEGRAL_TYPE_P
7737 {
7746 }
7748 }
7750 {
7752 {
7756 }
7760 integer_one_node),
7762 integer_zero_node));
7763 }
7764 }
7767 {
7769 /* Re-association barriers around constants and other re-association
7770 barriers can be removed. */
7776 CASE_CONVERT:
7782 /* If we have (type) (a CMP b) and type is an integral type, return
7783 new expression involving the new type. */
7788 /* Handle cases of two conversions in a row. */
7790 {
7812 /* In addition to the cases of two conversions in a row
7813 handled below, if we are converting something to its own
7814 type via an object of identical or wider precision, neither
7815 conversion is needed. */
7822 /* Likewise, if the intermediate and initial types are either both
7823 float or both integer, we don't need the middle conversion if the
7824 former is wider than the latter and doesn't change the signedness
7825 (for integers). Avoid this if the final type is a pointer since
7826 then we sometimes need the middle conversion. Likewise if the
7827 final type has a precision not equal to the size of its mode. */
7836 && ! final_ptr
7840 /* If we have a sign-extension of a zero-extended value, we can
7841 replace that by a single zero-extension. */
7847 /* Two conversions in a row are not needed unless:
7848 - some conversion is floating-point (overstrict for now), or
7849 - some conversion is a vector (overstrict for now), or
7850 - the intermediate type is narrower than both initial and
7851 final, or
7852 - the intermediate type and innermost type differ in signedness,
7853 and the outermost type is wider than the intermediate, or
7854 - the initial type is a pointer type and the precisions of the
7855 intermediate and final types differ, or
7856 - the final type is a pointer type and the precisions of the
7857 initial and intermediate types differ. */
7871 }
7873 /* Handle (T *)&A.B.C for A being of type T and B and C
7874 living at offset zero. This occurs frequently in
7875 C++ upcasting and then accessing the base. */
7879 {
7881 tree offset;
7887 /* If the reference was to a (constant) zero offset, we can use
7888 the address of the base if it has the same base type
7889 as the result type and the pointer type is unqualified. */
7896 }
7900 /* Detect assigning a bitfield. */
7902 && DECL_BIT_FIELD
7904 {
7905 /* Don't leave an assignment inside a conversion
7906 unless assigning a bitfield. */
7908 /* First do the assignment, then return converted constant. */
7914 }
7916 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7917 constants (if x has signed type, the sign bit cannot be set
7918 in c). This folds extension into the BIT_AND_EXPR.
7919 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7920 very likely don't have maximal range for their precision and this
7921 transformation effectively doesn't preserve non-maximal ranges. */
7925 {
7936 <= HOST_BITS_PER_WIDE_INT
7938 {
7945 #ifdef LOAD_EXTEND_OP
7947 && !flag_syntax_only
7950 {
7954 }
7955 #endif
7956 }
7958 {
7964 }
7965 }
7967 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7968 when one of the new casts will fold away. Conservatively we assume
7969 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7975 {
7983 }
7985 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7986 of the same precision, and X is an integer type not narrower than
7987 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7993 {
7999 }
8001 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
8002 type of X and Y (integer types only). */
8007 {
8008 /* Be careful not to introduce new overflows. */
8009 tree mult_type;
8012 else
8016 {
8023 }
8024 }
8045 /* For integral conversions with the same precision or pointer
8046 conversions use a NOP_EXPR instead. */
8054 /* Strip inner integral conversions that do not change the precision. */
8078 /* Convert fabs((double)float) into (double)fabsf(float). */
8081 {
8087 targ0));
8088 }
8089 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8095 /* Strip sign ops from argument. */
8097 {
8102 }
8109 {
8115 }
8117 {
8122 }
8132 /* Convert ~ (-A) to A - 1. */
8137 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8146 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8161 /* Perform BIT_NOT_EXPR on each element individually. */
8163 {
8168 {
8170 {
8176 }
8177 else
8180 }
8183 }
8188 /* The argument to invert_truthvalue must have Boolean type. */
8192 /* Note that the operand of this must be an int
8193 and its values must be 0 or 1.
8194 ("true" is a fixed value perhaps depending on the language,
8195 but we don't handle values other than 1 correctly yet.) */
8210 {
8218 }
8220 {
8225 }
8227 {
8231 {
8240 }
8241 }
8253 {
8261 }
8263 {
8267 }
8269 {
8273 {
8282 }
8283 }
8287 /* Fold *&X to X if X is an lvalue. */
8289 {
8296 }
8302 }
8305 /* If the operation was a conversion do _not_ mark a resulting constant
8306 with TREE_OVERFLOW if the original constant was not. These conversions
8307 have implementation defined behavior and retaining the TREE_OVERFLOW
8308 flag here would confuse later passes such as VRP. */
8309 tree
8312 {
8321 }
8323 /* Fold a binary expression of code CODE and type TYPE with operands
8324 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8325 Return the folded expression if folding is successful. Otherwise,
8326 return NULL_TREE. */
8328 static tree
8330 {
8337 else
8340 /* MIN (MAX (a, b), b) == b. */
8345 /* MIN (MAX (b, a), b) == b. */
8351 /* MIN (a, MAX (a, b)) == a. */
8357 /* MIN (a, MAX (b, a)) == a. */
8364 }
8366 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8367 by changing CODE to reduce the magnitude of constants involved in
8368 ARG0 of the comparison.
8369 Returns a canonicalized comparison tree if a simplification was
8370 possible, otherwise returns NULL_TREE.
8371 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8372 valid if signed overflow is undefined. */
8374 static tree
8378 {
8384 /* Match A +- CST code arg1 and CST code arg1. We can change the
8385 first form only if overflow is undefined. */
8387 /* In principle pointers also have undefined overflow behavior,
8388 but that causes problems elsewhere. */
8396 /* Identify the constant in arg0 and its sign. */
8399 else
8403 /* Overflowed constants and zero will cause problems. */
8408 /* See if we can reduce the magnitude of the constant in
8409 arg0 by changing the comparison code. */
8411 {
8412 /* CST <= arg1 -> CST-1 < arg1. */
8415 /* -CST < arg1 -> -CST-1 <= arg1. */
8418 /* CST > arg1 -> CST-1 >= arg1. */
8421 /* -CST >= arg1 -> -CST-1 > arg1. */
8424 else
8426 /* arg1 code' CST' might be more canonical. */
8428 }
8429 else
8430 {
8431 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8435 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8439 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8443 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8447 else
8450 }
8452 /* Now build the constant reduced in magnitude. But not if that
8453 would produce one outside of its types range. */
8461 /* We cannot swap the comparison here as that would cause us to
8462 endlessly recurse. */
8470 /* If swapping might yield to a more canonical form, do so. */
8473 else
8475 }
8477 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8478 overflow further. Try to decrease the magnitude of constants involved
8479 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8480 and put sole constants at the second argument position.
8481 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8483 static tree
8486 {
8487 tree t;
8492 /* Try canonicalization by simplifying arg0. */
8497 {
8501 }
8503 /* Try canonicalization by simplifying arg1 using the swapped
8504 comparison. */
8512 }
8514 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8515 space. This is used to avoid issuing overflow warnings for
8516 expressions like &p->x which can not wrap. */
8518 static bool
8520 {
8531 {
8534 }
8537 else
8538 {
8541 }
8556 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8557 array. */
8559 {
8560 HOST_WIDE_INT base_size;
8565 }
8568 }
8570 /* Subroutine of fold_binary. This routine performs all of the
8571 transformations that are common to the equality/inequality
8572 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8573 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8574 fold_binary should call fold_binary. Fold a comparison with
8575 tree code CODE and type TYPE with operands OP0 and OP1. Return
8576 the folded comparison or NULL_TREE. */
8578 static tree
8581 {
8594 /* If one arg is a real or integer constant, put it last. */
8598 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8605 {
8609 tree lhs;
8616 /* If the constant operation overflowed this can be
8617 simplified as a comparison against INT_MAX/INT_MIN. */
8620 {
8624 /* Get the sign of the constant on the lhs if the
8625 operation were VARIABLE + CONST1. */
8629 /* The sign of the constant determines if we overflowed
8630 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8631 Canonicalize to the INT_MIN overflow by swapping the comparison
8632 if necessary. */
8636 /* We now can look at the canonicalized case
8637 VARIABLE + 1 CODE2 INT_MIN
8638 and decide on the result. */
8647 }
8652 {
8654 "when changing X +- C1 cmp C2 to "
8656 WARN_STRICT_OVERFLOW_COMPARISON);
8658 }
8659 }
8661 /* For comparisons of pointers we can decompose it to a compile time
8662 comparison of the base objects and the offsets into the object.
8663 This requires at least one operand being an ADDR_EXPR or a
8664 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8670 {
8677 /* Get base and offset for the access. Strip ADDR_EXPR for
8678 get_inner_reference, but put it back by stripping INDIRECT_REF
8679 off the base object if possible. indirect_baseN will be true
8680 if baseN is not an address but refers to the object itself. */
8683 {
8689 else
8691 }
8693 {
8696 }
8700 {
8706 else
8708 }
8710 {
8713 }
8715 /* A local variable can never be pointed to by
8716 the default SSA name of an incoming parameter. */
8718 && indirect_base0
8721 && !indirect_base1
8726 && indirect_base1
8729 && !indirect_base0
8733 {
8738 }
8739 /* If we have equivalent bases we might be able to simplify. */
8742 {
8743 /* We can fold this expression to a constant if the non-constant
8744 offset parts are equal. */
8752 {
8759 "occur when comparing P +- C1 with "
8761 WARN_STRICT_OVERFLOW_CONDITIONAL);
8764 {
8778 }
8779 }
8780 /* We can simplify the comparison to a comparison of the variable
8781 offset parts if the constant offset parts are equal.
8782 Be careful to use signed size type here because otherwise we
8783 mess with array offsets in the wrong way. This is possible
8784 because pointer arithmetic is restricted to retain within an
8785 object and overflow on pointer differences is undefined as of
8786 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8790 {
8791 /* By converting to signed size type we cover middle-end pointer
8792 arithmetic which operates on unsigned pointer types of size
8793 type size and ARRAY_REF offsets which are properly sign or
8794 zero extended from their type in case it is narrower than
8795 size type. */
8798 else
8802 else
8810 "occur when comparing P +- C1 with "
8812 WARN_STRICT_OVERFLOW_COMPARISON);
8815 }
8816 }
8817 /* For non-equal bases we can simplify if they are addresses
8818 of local binding decls or constants. */
8820 /* We know that !operand_equal_p (base0, base1, 0)
8821 because the if condition was false. But make
8822 sure two decls are not the same. */
8836 {
8843 }
8844 /* For equal offsets we can simplify to a comparison of the
8845 base addresses. */
8847 && (indirect_base0
8849 && (indirect_base1
8854 {
8860 }
8861 }
8863 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8864 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8865 the resulting offset is smaller in absolute value than the
8866 original one. */
8874 {
8879 tree cst;
8881 "occur when combining constants around "
8884 /* Put the constant on the side where it doesn't overflow and is
8885 of lower absolute value than before. */
8891 {
8894 variable1,
8898 }
8905 {
8910 variable2);
8911 }
8912 }
8914 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8915 signed arithmetic case. That form is created by the compiler
8916 often enough for folding it to be of value. One example is in
8917 computing loop trip counts after Operator Strength Reduction. */
8923 {
8929 /* Handle unfolded multiplication by zero. */
8934 "eliminating multiplication in comparison "
8936 WARN_STRICT_OVERFLOW_COMPARISON);
8938 /* If const1 is negative we swap the sense of the comparison. */
8943 }
8950 {
8958 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8964 /* (-a) CMP (-b) -> b CMP a */
8971 {
8972 REAL_VALUE_TYPE cst;
8975 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8982 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8983 /* a CMP (-0) -> a CMP 0 */
8988 /* x != NaN is always true, other ops are always false. */
8991 {
8994 }
8996 /* Fold comparisons against infinity. */
8999 {
9003 }
9004 }
9006 /* If this is a comparison of a real constant with a PLUS_EXPR
9007 or a MINUS_EXPR of a real constant, we can convert it into a
9008 comparison with a revised real constant as long as no overflow
9009 occurs when unsafe_math_optimizations are enabled. */
9021 /* Likewise, we can simplify a comparison of a real constant with
9022 a MINUS_EXPR whose first operand is also a real constant, i.e.
9023 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9024 floating-point types only if -fassociative-math is set. */
9035 /* Fold comparisons against built-in math functions. */
9037 && flag_unsafe_math_optimizations
9039 {
9043 {
9047 }
9048 }
9049 }
9053 {
9054 /* If we are widening one operand of an integer comparison,
9055 see if the other operand is similarly being widened. Perhaps we
9056 can do the comparison in the narrower type. */
9061 /* Or if we are changing signedness. */
9065 }
9067 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9068 constant, we can simplify it. */
9073 {
9077 }
9079 /* Simplify comparison of something with itself. (For IEEE
9080 floating-point, we can only do some of these simplifications.) */
9082 {
9084 {
9099 /* For NE, we can only do this simplification if integer
9100 or we don't honor IEEE floating point NaNs. */
9104 /* ... fall through ... */
9110 }
9111 }
9113 /* If we are comparing an expression that just has comparisons
9114 of two integer values, arithmetic expressions of those comparisons,
9115 and constants, we can simplify it. There are only three cases
9116 to check: the two values can either be equal, the first can be
9117 greater, or the second can be greater. Fold the expression for
9118 those three values. Since each value must be 0 or 1, we have
9119 eight possibilities, each of which corresponds to the constant 0
9120 or 1 or one of the six possible comparisons.
9122 This handles common cases like (a > b) == 0 but also handles
9123 expressions like ((x > y) - (y > x)) > 0, which supposedly
9124 occur in macroized code. */
9127 {
9132 /* Don't handle degenerate cases here; they should already
9133 have been handled anyway. */
9142 {
9146 /* We can't just pass T to eval_subst in case cval1 or cval2
9147 was the same as ARG1. */
9149 tree high_result
9153 arg1);
9154 tree equal_result
9158 arg1);
9159 tree low_result
9163 arg1);
9165 /* All three of these results should be 0 or 1. Confirm they are.
9166 Then use those values to select the proper code to use. */
9171 {
9172 /* Make a 3-bit mask with the high-order bit being the
9173 value for `>', the next for '=', and the low for '<'. */
9177 {
9179 /* Always false. */
9200 /* Always true. */
9202 }
9205 {
9209 }
9211 }
9212 }
9213 }
9215 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9216 into a single range test. */
9224 {
9228 }
9230 /* Fold ~X op ~Y as Y op X. */
9233 {
9239 }
9241 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9244 {
9250 }
9253 }
9256 /* Subroutine of fold_binary. Optimize complex multiplications of the
9257 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9258 argument EXPR represents the expression "z" of type TYPE. */
9260 static tree
9262 {
9267 {
9270 }
9272 {
9275 }
9276 else
9277 {
9281 }
9290 }
9293 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9294 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9295 guarantees that P and N have the same least significant log2(M) bits.
9296 N is not otherwise constrained. In particular, N is not normalized to
9297 0 <= N < M as is common. In general, the precise value of P is unknown.
9298 M is chosen as large as possible such that constant N can be determined.
9300 Returns M and sets *RESIDUE to N.
9302 If ALLOW_FUNC_ALIGN is true, do take functions' DECL_ALIGN_UNIT into
9303 account. This is not always possible due to PR 35705.
9304 */
9306 static unsigned HOST_WIDE_INT
9309 {
9316 {
9319 {
9321 tree offset;
9329 {
9332 else
9333 /* We don't handle more complicated offset expressions. */
9335 }
9336 }
9341 }
9343 {
9351 allow_func_align);
9357 {
9360 }
9362 {
9365 {
9368 /* Compute the greatest power-of-2 divisor of op1. */
9372 /* If align is non-zero and less than *modulus, replace
9373 *modulus with align., If align is 0, then either op1 is 0
9374 or the greatest power-of-2 divisor of op1 doesn't fit in an
9375 unsigned HOST_WIDE_INT. In either case, no additional
9376 constraint is imposed. */
9381 }
9382 }
9383 }
9385 /* If we get here, we were unable to determine anything useful about the
9386 expression. */
9388 }
9391 /* Fold a binary expression of code CODE and type TYPE with operands
9392 OP0 and OP1. LOC is the location of the resulting expression.
9393 Return the folded expression if folding is successful. Otherwise,
9394 return NULL_TREE. */
9396 tree
9399 {
9413 /* Strip any conversions that don't change the mode. This is
9414 safe for every expression, except for a comparison expression
9415 because its signedness is derived from its operands. So, in
9416 the latter case, only strip conversions that don't change the
9417 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9418 preserved.
9420 Note that this is done as an internal manipulation within the
9421 constant folder, in order to find the simplest representation
9422 of the arguments so that their form can be studied. In any
9423 cases, the appropriate type conversions should be put back in
9424 the tree that will get out of the constant folder. */
9427 {
9430 }
9431 else
9432 {
9435 }
9437 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9438 constant but we can't do arithmetic on them. */
9445 {
9447 {
9448 /* Make sure type and arg0 have the same saturating flag. */
9452 }
9455 else
9459 {
9463 }
9464 }
9466 /* If this is a commutative operation, and ARG0 is a constant, move it
9467 to ARG1 to reduce the number of tests below. */
9472 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9474 First check for cases where an arithmetic operation is applied to a
9475 compound, conditional, or comparison operation. Push the arithmetic
9476 operation inside the compound or conditional to see if any folding
9477 can then be done. Convert comparison to conditional for this purpose.
9478 The also optimizes non-constant cases that used to be done in
9479 expand_expr.
9481 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9482 one of the operands is a comparison and the other is a comparison, a
9483 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9484 code below would make the expression more complex. Change it to a
9485 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9486 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9498 {
9502 boolean_type_node,
9510 }
9514 {
9516 {
9522 }
9525 {
9531 }
9534 {
9540 }
9543 {
9549 }
9550 }
9553 {
9555 /* 0 +p index -> (type)index */
9559 /* PTR +p 0 -> PTR */
9563 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9569 arg1),
9571 arg0)));
9573 /* index +p PTR -> PTR +p index */
9580 /* (PTR +p B) +p A -> PTR +p (B + A) */
9582 {
9583 tree inner;
9592 }
9594 /* PTR_CST +p CST -> CST1 */
9599 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9600 of the array. Loop optimizer sometimes produce this type of
9601 expressions. */
9603 {
9608 }
9613 /* A + (-B) -> A - B */
9619 /* (-A) + B -> B - A */
9628 {
9629 /* Convert ~A + 1 to -A. */
9636 /* ~X + X is -1. */
9639 {
9644 {
9647 }
9648 }
9650 /* X + ~X is -1. */
9653 {
9658 {
9661 }
9662 }
9664 /* X + (X / CST) * -CST is X % CST. */
9669 {
9678 cst0));
9679 }
9680 }
9682 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9683 same or one. Make sure type is not saturating.
9684 fold_plusminus_mult_expr will re-associate. */
9689 {
9693 }
9696 {
9700 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9701 with a constant, and the two constants have no bits in common,
9702 we should treat this as a BIT_IOR_EXPR since this may produce more
9703 simplifications. */
9711 {
9714 }
9716 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9717 (plus (plus (mult) (mult)) (foo)) so that we can
9718 take advantage of the factoring cases below. */
9725 {
9731 else
9744 parg0),
9746 marg)),
9750 return
9756 parg1)));
9757 }
9758 }
9759 else
9760 {
9761 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9765 /* Likewise if the operands are reversed. */
9769 /* Convert X + -C into X - C. */
9772 {
9778 }
9780 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9781 to __complex__ ( x, y ). This is not the same for SNaNs or
9782 if signed zeros are involved. */
9786 {
9793 {
9797 {
9803 }
9805 {
9811 }
9812 }
9813 }
9821 /* Convert x+x into x*2.0. */
9827 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9828 We associate floats only if the user has specified
9829 -fassociative-math. */
9833 {
9838 {
9839 tree tree0;
9842 }
9843 }
9844 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9845 We associate floats only if the user has specified
9846 -fassociative-math. */
9850 {
9855 {
9856 tree tree0;
9859 }
9860 }
9861 }
9863 bit_rotate:
9864 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9865 is a rotate of A by C1 bits. */
9866 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9867 is a rotate of A by B bits. */
9868 {
9870 tree rtype;
9879 /* Only create rotates in complete modes. Other cases are not
9880 expanded properly. */
9882 {
9898 {
9902 code0 == LSHIFT_EXPR
9906 }
9908 {
9916 TYPE_PRECISION
9920 return
9923 ? LROTATE_EXPR
9927 }
9929 {
9937 TYPE_PRECISION
9941 return fold_convert_loc
9944 ? LROTATE_EXPR
9948 }
9949 }
9950 }
9952 associate:
9953 /* In most languages, can't associate operations on floats through
9954 parentheses. Rather than remember where the parentheses were, we
9955 don't associate floats at all, unless the user has specified
9956 -fassociative-math.
9957 And, we need to make sure type is not saturating. */
9961 {
9966 /* Split both trees into variables, constants, and literals. Then
9967 associate each group together, the constants with literals,
9968 then the result with variables. This increases the chances of
9969 literals being recombined later and of generating relocatable
9970 expressions for the sum of a constant and literal. */
9975 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9979 /* With undefined overflow we can only associate constants with one
9980 variable, and constants whose association doesn't overflow. */
9983 {
9985 {
9993 /* The only case we can still associate with two variables
9994 is if they are the same, modulo negation. */
9997 }
10000 {
10007 }
10008 }
10010 /* Only do something if we found more than two objects. Otherwise,
10011 nothing has changed and we risk infinite recursion. */
10017 {
10023 /* Preserve the MINUS_EXPR if the negative part of the literal is
10024 greater than the positive part. Otherwise, the multiplicative
10025 folding code (i.e extract_muldiv) may be fooled in case
10026 unsigned constants are subtracted, like in the following
10027 example: ((X*2 + 4) - 8U)/2. */
10029 {
10033 {
10037 }
10038 else
10039 {
10043 }
10044 }
10046 {
10048 return
10052 else
10053 {
10056 return
10060 }
10061 }
10064 return
10067 }
10068 }
10073 /* Pointer simplifications for subtraction, simple reassociations. */
10075 {
10076 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10079 {
10089 }
10090 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10092 {
10099 }
10100 }
10101 /* A - (-B) -> A + B */
10106 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10117 /* Convert -A - 1 to ~A. */
10126 /* Convert -1 - A to ~A. */
10132 /* X - (X / CST) * CST is X % CST. */
10140 return
10146 {
10152 /* Fold A - (A & B) into ~B & A. */
10155 {
10157 {
10164 }
10166 {
10173 }
10174 }
10176 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10177 any power of 2 minus 1. */
10182 {
10188 {
10192 }
10193 }
10194 }
10196 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10200 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10201 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10202 (-ARG1 + ARG0) reduces to -ARG1. */
10206 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10207 __complex__ ( x, -y ). This is not the same for SNaNs or if
10208 signed zeros are involved. */
10212 {
10219 {
10223 {
10225 arg1r ? arg1r
10230 }
10232 {
10236 arg1i ? arg1i
10239 }
10240 }
10241 }
10243 /* Fold &x - &x. This can happen from &x.foo - &x.
10244 This is unsafe for certain floats even in non-IEEE formats.
10245 In IEEE, it is unsafe because it does wrong for NaNs.
10246 Also note that operand_equal_p is always false if an operand
10247 is volatile. */
10253 /* A - B -> A + (-B) if B is easily negatable. */
10256 /* Avoid this transformation if B is a positive REAL_CST. */
10265 /* Try folding difference of addresses. */
10266 {
10267 HOST_WIDE_INT diff;
10273 }
10275 /* Fold &a[i] - &a[j] to i-j. */
10280 {
10285 {
10293 }
10294 }
10297 && flag_unsafe_math_optimizations
10303 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10304 same or one. Make sure type is not saturating.
10305 fold_plusminus_mult_expr will re-associate. */
10310 {
10314 }
10319 /* (-A) * (-B) -> A * B */
10334 {
10339 /* Transform x * -1 into -x. Make sure to do the negation
10340 on the original operand with conversions not stripped
10341 because we can only strip non-sign-changing conversions. */
10344 /* Transform x * -C into -x * C if x is easily negatable. */
10353 tem);
10355 /* (a * (1 << b)) is (a << b) */
10365 /* (A + A) * C -> A * 2 * C */
10381 {
10384 "occur when simplifying "
10386 WARN_STRICT_OVERFLOW_MISC);
10388 }
10390 /* Optimize z * conj(z) for integer complex numbers. */
10397 }
10398 else
10399 {
10400 /* Maybe fold x * 0 to 0. The expressions aren't the same
10401 when x is NaN, since x * 0 is also NaN. Nor are they the
10402 same in modes with signed zeros, since multiplying a
10403 negative value by 0 gives -0, not +0. */
10408 /* In IEEE floating point, x*1 is not equivalent to x for snans.
10409 Likewise for complex arithmetic with signed zeros. */
10416 /* Transform x * -1.0 into -x. */
10423 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10424 the result for floating point types due to rounding so it is applied
10425 only if -fassociative-math was specify. */
10430 {
10436 }
10438 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10440 {
10443 {
10446 }
10447 }
10449 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10450 This is not the same for NaNs or if signed zeros are
10451 involved. */
10457 {
10460 return
10466 return
10471 }
10473 /* Optimize z * conj(z) for floating point complex numbers.
10474 Guarded by flag_unsafe_math_optimizations as non-finite
10475 imaginary components don't produce scalar results. */
10486 {
10490 /* Optimizations of root(...)*root(...). */
10492 {
10497 /* Optimize sqrt(x)*sqrt(x) as x. */
10503 /* Optimize root(x)*root(y) as root(x*y). */
10507 }
10509 /* Optimize expN(x)*expN(y) as expN(x+y). */
10511 {
10517 }
10519 /* Optimizations of pow(...)*pow(...). */
10523 {
10529 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10531 {
10536 }
10538 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10540 {
10545 }
10546 }
10548 /* Optimize tan(x)*cos(x) as sin(x). */
10557 {
10563 }
10565 /* Optimize x*pow(x,c) as pow(x,c+1). */
10569 {
10575 {
10577 REAL_VALUE_TYPE c;
10578 tree arg;
10584 }
10585 }
10587 /* Optimize pow(x,c)*x as pow(x,c+1). */
10591 {
10597 {
10599 REAL_VALUE_TYPE c;
10600 tree arg;
10606 }
10607 }
10609 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10612 {
10616 {
10619 }
10620 }
10621 }
10622 }
10626 bit_ior:
10634 /* ~X | X is -1. */
10637 {
10641 }
10643 /* X | ~X is -1. */
10646 {
10650 }
10652 /* Canonicalize (X & C1) | C2. */
10656 {
10664 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10670 {
10674 }
10675 else
10676 {
10680 }
10682 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10687 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10688 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10689 mode which allows further optimizations. */
10699 {
10700 unsigned HOST_WIDE_INT mask
10704 {
10708 }
10709 }
10716 arg1);
10717 }
10719 /* (X & Y) | Y is (X, Y). */
10723 /* (X & Y) | X is (Y, X). */
10728 /* X | (X & Y) is (Y, X). */
10733 /* X | (Y & X) is (Y, X). */
10743 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10745 This results in more efficient code for machines without a NAND
10746 instruction. Combine will canonicalize to the first form
10747 which will allow use of NAND instructions provided by the
10748 backend if they exist. */
10751 {
10752 return
10759 }
10761 /* See if this can be simplified into a rotate first. If that
10762 is unsuccessful continue in the association code. */
10773 /* ~X ^ X is -1. */
10776 {
10780 }
10782 /* X ^ ~X is -1. */
10785 {
10789 }
10791 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10792 with a constant, and the two constants have no bits in common,
10793 we should treat this as a BIT_IOR_EXPR since this may produce more
10794 simplifications. */
10802 {
10805 }
10807 /* (X | Y) ^ X -> Y & ~ X*/
10810 {
10813 arg1);
10818 }
10820 /* (Y | X) ^ X -> Y & ~ X*/
10823 {
10826 arg1);
10831 }
10833 /* X ^ (X | Y) -> Y & ~ X*/
10836 {
10839 arg0);
10844 }
10846 /* X ^ (Y | X) -> Y & ~ X*/
10849 {
10852 arg0);
10857 }
10859 /* Convert ~X ^ ~Y to X ^ Y. */
10868 /* Convert ~X ^ C to X ^ ~C. */
10876 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10883 /* Fold (X & Y) ^ Y as ~X & Y. */
10886 {
10891 }
10892 /* Fold (X & Y) ^ X as ~Y & X. */
10896 {
10901 }
10902 /* Fold X ^ (X & Y) as X & ~Y. */
10905 {
10910 }
10911 /* Fold X ^ (Y & X) as ~Y & X. */
10915 {
10920 }
10922 /* See if this can be simplified into a rotate first. If that
10923 is unsuccessful continue in the association code. */
10934 /* ~X & X is always zero. */
10939 /* X & ~X is always zero. */
10944 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10948 {
10954 return
10958 }
10960 /* (X | Y) & Y is (X, Y). */
10964 /* (X | Y) & X is (Y, X). */
10969 /* X & (X | Y) is (Y, X). */
10974 /* X & (Y | X) is (Y, X). */
10980 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10984 {
10990 }
10991 /* Fold ~X & 1 as (X & 1) == 0. */
10994 {
11000 }
11002 /* Fold (X ^ Y) & Y as ~X & Y. */
11005 {
11010 }
11011 /* Fold (X ^ Y) & X as ~Y & X. */
11015 {
11020 }
11021 /* Fold X & (X ^ Y) as X & ~Y. */
11024 {
11029 }
11030 /* Fold X & (Y ^ X) as ~Y & X. */
11034 {
11039 }
11044 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11047 {
11048 unsigned int prec
11054 return
11056 }
11058 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
11060 This results in more efficient code for machines without a NOR
11061 instruction. Combine will canonicalize to the first form
11062 which will allow use of NOR instructions provided by the
11063 backend if they exist. */
11066 {
11073 }
11075 /* If arg0 is derived from the address of an object or function, we may
11076 be able to fold this expression using the object or function's
11077 alignment. */
11079 {
11086 /* This works because modulus is a power of 2. If this weren't the
11087 case, we'd have to replace it by its greatest power-of-2
11088 divisor: modulus & -modulus. */
11091 }
11093 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
11094 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
11095 if the new mask might be further optimized. */
11104 {
11106 unsigned HOST_WIDE_INT mask
11116 {
11119 /* See if more bits can be proven as zero because of
11120 zero extension. */
11123 {
11128 {
11130 /* See if we can shorten the right shift. */
11133 }
11134 }
11138 /* For arithmetic shift if sign bit could be set, zerobits
11139 can contain actually sign bits, so no transformation is
11140 possible, unless MASK masks them all away. In that
11141 case the shift needs to be converted into logical shift. */
11144 {
11147 else
11149 }
11150 }
11152 /* ((X << 16) & 0xff00) is (X, 0). */
11159 {
11162 /* Only do the transformation if NEWMASK is some integer
11163 mode's mask. */
11170 {
11171 tree newmaskt;
11174 {
11180 }
11181 else
11186 }
11187 }
11188 }
11193 /* Don't touch a floating-point divide by zero unless the mode
11194 of the constant can represent infinity. */
11200 /* Optimize A / A to 1.0 if we don't care about
11201 NaNs or Infinities. Skip the transformation
11202 for non-real operands. */
11207 {
11211 }
11213 /* The complex version of the above A / A optimization. */
11216 {
11220 {
11222 /* omit_two_operands will call fold_convert for us. */
11224 }
11225 }
11227 /* (-A) / (-B) -> A / B */
11237 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11242 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11248 /* If ARG1 is a constant, we can convert this to a multiply by the
11249 reciprocal. This does not have the same rounding properties,
11250 so only do this if -freciprocal-math. We can actually
11251 always safely do it if ARG1 is a power of two, but it's hard to
11252 tell if it is or not in a portable manner. */
11254 {
11259 /* Find the reciprocal if optimizing and the result is exact. */
11261 {
11262 REAL_VALUE_TYPE r;
11265 {
11269 }
11270 }
11271 }
11272 /* Convert A/B/C to A/(B*C). */
11279 /* Convert A/(B/C) to (A/B)*C. */
11287 /* Convert C1/(X*C2) into (C1/C2)/X. */
11292 {
11298 }
11301 {
11305 /* Optimize sin(x)/cos(x) as tan(x). */
11311 {
11316 }
11318 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11324 {
11328 {
11333 }
11334 }
11336 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11337 NaNs or Infinities. */
11341 {
11348 {
11353 }
11354 }
11356 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11357 NaNs or Infinities. */
11361 {
11368 {
11372 {
11376 tmp);
11377 }
11378 }
11379 }
11381 /* Optimize pow(x,c)/x as pow(x,c-1). */
11385 {
11391 {
11393 REAL_VALUE_TYPE c;
11394 tree arg;
11400 }
11401 }
11403 /* Optimize a/root(b/c) into a*root(c/b). */
11405 {
11409 {
11418 }
11419 }
11421 /* Optimize x/expN(y) into x*expN(-y). */
11423 {
11430 }
11432 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11436 {
11444 }
11445 }
11450 /* Simplify A / (B << N) where A and B are positive and B is
11451 a power of 2, to A >> (N + log2(B)). */
11456 {
11459 {
11466 WARN_STRICT_OVERFLOW_MISC);
11472 }
11473 }
11475 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11476 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11482 /* Fall thru */
11491 /* X / -1 is -X. */
11498 /* Convert -A / -B to A / B when the type is signed and overflow is
11499 undefined. */
11503 {
11506 "when distributing negation across "
11508 WARN_STRICT_OVERFLOW_MISC);
11514 }
11518 {
11521 "when distributing negation across "
11523 WARN_STRICT_OVERFLOW_MISC);
11529 }
11531 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11532 operation, EXACT_DIV_EXPR.
11534 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11535 At one time others generated faster code, it's not clear if they do
11536 after the last round to changes to the DIV code in expmed.c. */
11545 {
11549 WARN_STRICT_OVERFLOW_MISC);
11551 }
11559 /* X % 1 is always zero, but be sure to preserve any side
11560 effects in X. */
11564 /* X % 0, return X % 0 unchanged so that we can get the
11565 proper warnings and errors. */
11569 /* 0 % X is always zero, but be sure to preserve any side
11570 effects in X. Place this after checking for X == 0. */
11574 /* X % -1 is zero. */
11581 /* X % -C is the same as X % C. */
11588 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11595 /* X % -Y is the same as X % Y. */
11608 {
11612 WARN_STRICT_OVERFLOW_MISC);
11614 }
11616 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11617 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11621 {
11623 /* Also optimize A % (C << N) where C is a power of 2,
11624 to A & ((C << N) - 1). */
11629 {
11630 tree mask
11635 "occur when simplifying "
11637 WARN_STRICT_OVERFLOW_MISC);
11641 }
11642 }
11653 /* Optimize -1 >> x for arithmetic right shifts. */
11657 /* ... fall through ... */
11660 shift:
11666 /* Since negative shift count is not well-defined,
11667 don't try to compute it in the compiler. */
11671 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11676 {
11680 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11681 being well defined. */
11683 {
11689 else
11691 }
11695 }
11697 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11698 into x & ((unsigned)-1 >> c) for unsigned types. */
11706 {
11709 tree lshift;
11710 tree arg00;
11713 {
11720 }
11721 }
11723 /* Rewrite an LROTATE_EXPR by a constant into an
11724 RROTATE_EXPR by a new constant. */
11726 {
11731 }
11733 /* If we have a rotate of a bit operation with the rotate count and
11734 the second operand of the bit operation both constant,
11735 permute the two operations. */
11747 /* Two consecutive rotates adding up to the precision of the
11748 type can be ignored. */
11759 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11760 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11761 if the latter can be further optimized. */
11766 {
11770 arg1);
11774 arg1);
11778 }
11806 /* Note that the operands of this must be ints
11807 and their values must be 0 or 1.
11808 ("true" is a fixed value perhaps depending on the language.) */
11809 /* If first arg is constant zero, return it. */
11813 /* If either arg is constant true, drop it. */
11817 /* Preserve sequence points. */
11820 /* If second arg is constant zero, result is zero, but first arg
11821 must be evaluated. */
11824 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11825 case will be handled here. */
11829 /* !X && X is always false. */
11833 /* X && !X is always false. */
11838 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11839 means A >= Y && A != MAX, but in this case we know that
11840 A < X <= MAX. */
11844 {
11852 }
11854 truth_andor:
11855 /* We only do these simplifications if we are optimizing. */
11859 /* Check for things like (A || B) && (A || C). We can convert this
11860 to A || (B && C). Note that either operator can be any of the four
11861 truth and/or operations and the transformation will still be
11862 valid. Also note that we only care about order for the
11863 ANDIF and ORIF operators. If B contains side effects, this
11864 might change the truth-value of A. */
11871 {
11891 /* This case if tricky because we must either have commutative
11892 operators or else A10 must not have side-effects. */
11898 a01);
11899 }
11901 /* See if we can build a range comparison. */
11907 {
11911 }
11915 {
11919 }
11921 /* Check for the possibility of merging component references. If our
11922 lhs is another similar operation, try to merge its rhs with our
11923 rhs. Then try to merge our lhs and rhs. */
11935 /* Note that the operands of this must be ints
11936 and their values must be 0 or true.
11937 ("true" is a fixed value perhaps depending on the language.) */
11938 /* If first arg is constant true, return it. */
11942 /* If either arg is constant zero, drop it. */
11946 /* Preserve sequence points. */
11949 /* If second arg is constant true, result is true, but we must
11950 evaluate first arg. */
11953 /* Likewise for first arg, but note this only occurs here for
11954 TRUTH_OR_EXPR. */
11958 /* !X || X is always true. */
11962 /* X || !X is always true. */
11970 /* If the second arg is constant zero, drop it. */
11973 /* If the second arg is constant true, this is a logical inversion. */
11975 {
11976 /* Only call invert_truthvalue if operand is a truth value. */
11979 else
11982 }
11983 /* Identical arguments cancel to zero. */
11987 /* !X ^ X is always true. */
11992 /* X ^ !X is always true. */
12005 /* bool_var != 0 becomes bool_var. */
12010 /* bool_var == 1 becomes bool_var. */
12015 /* bool_var != 1 becomes !bool_var. */
12021 /* bool_var == 0 becomes !bool_var. */
12027 /* !exp != 0 becomes !exp */
12032 /* If this is an equality comparison of the address of two non-weak,
12033 unaliased symbols neither of which are extern (since we do not
12034 have access to attributes for externs), then we know the result. */
12047 {
12048 /* We know that we're looking at the address of two
12049 non-weak, unaliased, static _DECL nodes.
12051 It is both wasteful and incorrect to call operand_equal_p
12052 to compare the two ADDR_EXPR nodes. It is wasteful in that
12053 all we need to do is test pointer equality for the arguments
12054 to the two ADDR_EXPR nodes. It is incorrect to use
12055 operand_equal_p as that function is NOT equivalent to a
12056 C equality test. It can in fact return false for two
12057 objects which would test as equal using the C equality
12058 operator. */
12062 type);
12063 }
12065 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
12066 a MINUS_EXPR of a constant, we can convert it into a comparison with
12067 a revised constant as long as no overflow occurs. */
12075 arg1),
12080 /* Similarly for a NEGATE_EXPR. */
12088 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
12096 arg1),
12099 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
12106 {
12110 val,
12114 }
12116 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
12121 {
12123 code == NE_EXPR
12126 }
12128 /* If we have X - Y == 0, we can convert that to X == Y and similarly
12129 for !=. Don't do this for ordered comparisons due to overflow. */
12135 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
12140 /* If this is an EQ or NE comparison with zero and ARG0 is
12141 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12142 two operations, but the latter can be done in one less insn
12143 on machines that have only two-operand insns or on which a
12144 constant cannot be the first operand. */
12147 {
12152 {
12159 arg1);
12160 }
12163 {
12170 arg1);
12171 }
12172 }
12174 /* If this is an NE or EQ comparison of zero against the result of a
12175 signed MOD operation whose second operand is a power of 2, make
12176 the MOD operation unsigned since it is simpler and equivalent. */
12184 {
12194 }
12196 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12197 C1 is a valid shift constant, and C2 is a power of two, i.e.
12198 a single bit. */
12202 == INTEGER_CST
12205 {
12210 /* Check for a valid shift count. */
12213 {
12217 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12218 can be rewritten as (X & (C2 << C1)) != 0. */
12220 {
12224 }
12225 /* Otherwise, for signed (arithmetic) shifts,
12226 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12227 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12231 /* Otherwise, of unsigned (logical) shifts,
12232 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12233 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12234 else
12238 arg000);
12239 }
12240 }
12242 /* If this is an NE comparison of zero with an AND of one, remove the
12243 comparison since the AND will give the correct value. */
12250 /* If we have (A & C) == C where C is a power of 2, convert this into
12251 (A & C) != 0. Similarly for NE_EXPR. */
12257 integer_zero_node));
12259 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12260 bit, then fold the expression into A < 0 or A >= 0. */
12265 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12266 Similarly for NE_EXPR. */
12270 {
12279 }
12281 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12282 Similarly for NE_EXPR. */
12286 {
12293 }
12295 /* If this is a comparison of a field, we may be able to simplify it. */
12298 /* Handle the constant case even without -O
12299 to make sure the warnings are given. */
12301 {
12305 }
12307 /* Optimize comparisons of strlen vs zero to a compare of the
12308 first character of the string vs zero. To wit,
12309 strlen(ptr) == 0 => *ptr == 0
12310 strlen(ptr) != 0 => *ptr != 0
12311 Other cases should reduce to one of these two (or a constant)
12312 due to the return value of strlen being unsigned. */
12315 {
12323 {
12328 }
12329 }
12331 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12332 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12336 {
12343 {
12345 {
12348 }
12351 }
12352 }
12354 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12360 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12365 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12372 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12380 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12381 (X & C) == 0 when C is a single bit. */
12386 {
12392 }
12394 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12395 constant C is a power of two, i.e. a single bit. */
12402 {
12406 }
12408 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12409 when is C is a power of two, i.e. a single bit. */
12416 {
12422 }
12426 {
12429 }
12431 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12438 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12441 {
12454 arg01),
12463 arg01),
12472 arg00),
12481 arg00),
12483 }
12487 {
12494 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12495 operand_equal_p guarantees no side-effects so we don't need
12496 to use omit_one_operand on Z. */
12506 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12514 arg10);
12515 }
12517 /* Attempt to simplify equality/inequality comparisons of complex
12518 values. Only lower the comparison if the result is known or
12519 can be simplified to a single scalar comparison. */
12524 {
12529 {
12532 }
12533 else
12534 {
12537 }
12540 {
12543 }
12544 else
12545 {
12548 }
12552 {
12554 {
12559 }
12560 else
12561 {
12566 }
12567 }
12571 {
12573 {
12578 }
12579 else
12580 {
12585 }
12586 }
12587 }
12599 /* Transform comparisons of the form X +- C CMP X. */
12606 {
12613 else
12616 /* (X - c) > X becomes false. */
12620 {
12624 "occur when assuming that (X - c) > X "
12626 WARN_STRICT_OVERFLOW_ALL);
12628 }
12630 /* Likewise (X + c) < X becomes false. */
12634 {
12638 "occur when assuming that "
12640 WARN_STRICT_OVERFLOW_ALL);
12642 }
12644 /* Convert (X - c) <= X to true. */
12649 {
12653 "occur when assuming that "
12655 WARN_STRICT_OVERFLOW_ALL);
12657 }
12659 /* Convert (X + c) >= X to true. */
12664 {
12668 "occur when assuming that "
12670 WARN_STRICT_OVERFLOW_ALL);
12672 }
12675 {
12676 /* Convert X + c > X and X - c < X to true for integers. */
12680 {
12683 "not occur when assuming that "
12685 WARN_STRICT_OVERFLOW_ALL);
12687 }
12692 {
12695 "not occur when assuming that "
12697 WARN_STRICT_OVERFLOW_ALL);
12699 }
12701 /* Convert X + c <= X and X - c >= X to false for integers. */
12705 {
12708 "not occur when assuming that "
12710 WARN_STRICT_OVERFLOW_ALL);
12712 }
12717 {
12720 "not occur when assuming that "
12722 WARN_STRICT_OVERFLOW_ALL);
12724 }
12725 }
12726 }
12728 /* Comparisons with the highest or lowest possible integer of
12729 the specified precision will have known values. */
12730 {
12737 {
12738 HOST_WIDE_INT signed_max_hi;
12743 {
12750 {
12754 }
12755 else
12756 {
12760 }
12761 }
12762 else
12763 {
12772 {
12775 }
12776 else
12777 {
12780 }
12781 }
12786 {
12799 /* The GE_EXPR and LT_EXPR cases above are not normally
12800 reached because of previous transformations. */
12804 }
12806 == max_hi
12809 {
12816 arg1);
12822 arg0),
12823 arg1);
12826 }
12828 == min_hi
12831 {
12846 }
12848 == min_hi
12851 {
12857 arg1);
12862 arg0),
12863 arg1);
12866 }
12871 /* We will flip the signedness of the comparison operator
12872 associated with the mode of arg1, so the sign bit is
12873 specified by this mode. Check that arg1 is the signed
12874 max associated with this sign bit. */
12876 /* signed_type does not work on pointer types. */
12878 {
12879 /* The following case also applies to X < signed_max+1
12880 and X >= signed_max+1 because previous transformations. */
12882 {
12883 tree st;
12889 }
12890 }
12891 }
12892 }
12894 /* If we are comparing an ABS_EXPR with a constant, we can
12895 convert all the cases into explicit comparisons, but they may
12896 well not be faster than doing the ABS and one comparison.
12897 But ABS (X) <= C is a range comparison, which becomes a subtraction
12898 and a comparison, and is probably faster. */
12912 /* Convert ABS_EXPR<x> >= 0 to true. */
12919 {
12922 "when simplifying comparison of "
12924 WARN_STRICT_OVERFLOW_CONDITIONAL);
12926 }
12928 /* Convert ABS_EXPR<x> < 0 to false. */
12933 {
12936 "when simplifying comparison of "
12938 WARN_STRICT_OVERFLOW_CONDITIONAL);
12940 }
12942 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12943 and similarly for >= into !=. */
12948 {
12954 }
12961 {
12970 }
12983 {
12987 }
12989 /* If the first operand is NaN, the result is constant. */
12993 {
12995 ? integer_zero_node
12998 }
13000 /* If the second operand is NaN, the result is constant. */
13004 {
13006 ? integer_zero_node
13009 }
13011 /* Simplify unordered comparison of something with itself. */
13017 && !flag_trapping_math
13021 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
13022 {
13034 }
13039 /* When pedantic, a compound expression can be neither an lvalue
13040 nor an integer constant expression. */
13043 /* Don't let (0, 0) be null pointer constant. */
13057 /* An ASSERT_EXPR should never be passed to fold_binary. */
13063 fold_binary_exit:
13066 }
13068 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
13069 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
13070 of GOTO_EXPR. */
13072 static tree
13074 {
13076 {
13083 /* ... fall through ... */
13087 }
13088 }
13090 /* Return whether the sub-tree ST contains a label which is accessible from
13091 outside the sub-tree. */
13093 static bool
13095 {
13096 return
13098 }
13100 /* Fold a ternary expression of code CODE and type TYPE with operands
13101 OP0, OP1, and OP2. Return the folded expression if folding is
13102 successful. Otherwise, return NULL_TREE. */
13104 tree
13107 {
13108 tree tem;
13115 /* Strip any conversions that don't change the mode. This is safe
13116 for every expression, except for a comparison expression because
13117 its signedness is derived from its operands. So, in the latter
13118 case, only strip conversions that don't change the signedness.
13120 Note that this is done as an internal manipulation within the
13121 constant folder, in order to find the simplest representation of
13122 the arguments so that their form can be studied. In any cases,
13123 the appropriate type conversions should be put back in the tree
13124 that will get out of the constant folder. */
13126 {
13129 }
13132 {
13135 }
13138 {
13142 {
13148 }
13152 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
13153 so all simple results must be passed through pedantic_non_lvalue. */
13155 {
13158 /* Only optimize constant conditions when the selected branch
13159 has the same type as the COND_EXPR. This avoids optimizing
13160 away "c ? x : throw", where the throw has a void type.
13161 Avoid throwing away that operand which contains label. */
13168 }
13172 /* If we have A op B ? A : C, we may be able to convert this to a
13173 simpler expression, depending on the operation and the values
13174 of B and C. Signed zeros prevent all of these transformations,
13175 for reasons given above each one.
13177 Also try swapping the arguments and inverting the conditional. */
13182 {
13186 }
13190 op2,
13193 {
13196 {
13200 }
13201 }
13203 /* If the second operand is simpler than the third, swap them
13204 since that produces better jump optimization results. */
13207 {
13208 /* See if this can be inverted. If it can't, possibly because
13209 it was a floating-point inequality comparison, don't do
13210 anything. */
13214 }
13216 /* Convert A ? 1 : 0 to simply A. */
13219 /* If we try to convert OP0 to our type, the
13220 call to fold will try to move the conversion inside
13221 a COND, which will recurse. In that case, the COND_EXPR
13222 is probably the best choice, so leave it alone. */
13226 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13227 over COND_EXPR in cases such as floating point comparisons. */
13234 arg0)));
13236 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13241 {
13242 /* sign_bit_p only checks ARG1 bits within A's precision.
13243 If <sign bit of A> has wider type than A, bits outside
13244 of A's precision in <sign bit of A> need to be checked.
13245 If they are all 0, this optimization needs to be done
13246 in unsigned A's type, if they are all 1 in signed A's type,
13247 otherwise this can't be done. */
13252 {
13254 HOST_WIDE_INT mask_hi;
13256 tree tem_type;
13264 {
13268 }
13269 else
13270 {
13274 }
13276 {
13280 }
13281 else
13287 {
13290 }
13293 {
13296 }
13297 else
13299 }
13302 return
13308 arg1)));
13309 }
13311 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13312 already handled above. */
13317 {
13326 }
13328 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13329 is probably obsolete because the first operand should be a
13330 truth value (that's why we have the two cases above), but let's
13331 leave it in until we can confirm this for all front-ends. */
13343 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13349 arg1);
13351 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13355 {
13356 /* Only perform transformation if ARG0 is easily inverted. */
13361 arg1);
13362 }
13364 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13368 {
13369 /* Only perform transformation if ARG0 is easily inverted. */
13374 op2);
13375 }
13377 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13383 op2);
13388 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13389 of fold_ternary on them. */
13396 {
13405 {
13410 else
13411 {
13413 tree value;
13417 }
13422 else
13424 }
13425 }
13427 /* A bit-field-ref that referenced the full argument can be stripped. */
13438 }
13440 /* Perform constant folding and related simplification of EXPR.
13441 The related simplifications include x*1 => x, x*0 => 0, etc.,
13442 and application of the associative law.
13443 NOP_EXPR conversions may be removed freely (as long as we
13444 are careful not to change the type of the overall expression).
13445 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13446 but we can constant-fold them if they have constant operands. */
13448 #ifdef ENABLE_FOLD_CHECKING
13449 # define fold(x) fold_1 (x)
13451 static
13452 #endif
13453 tree
13455 {
13459 tree tem;
13462 /* Return right away if a constant. */
13466 /* CALL_EXPR-like objects with variable numbers of operands are
13467 treated specially. */
13469 {
13471 {
13474 }
13476 }
13479 {
13484 {
13502 }
13503 }
13506 {
13508 {
13515 {
13520 /* Find a matching index by means of a binary search. */
13522 {
13538 else
13540 }
13541 }
13544 }
13552 }
13554 #ifdef ENABLE_FOLD_CHECKING
13555 #undef fold
13561 /* When --enable-checking=fold, compute a digest of expr before
13562 and after actual fold call to see if fold did not accidentally
13563 change original expr. */
13565 tree
13567 {
13568 tree ret;
13571 htab_t ht;
13590 }
13592 void
13594 {
13597 htab_t ht;
13607 }
13609 static void
13611 {
13613 }
13615 static void
13617 {
13623 recursive_label:
13637 {
13638 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13642 }
13649 {
13650 /* Allow these fields to be modified. */
13651 tree tmp;
13659 {
13662 }
13663 }
13672 {
13675 {
13689 }
13693 {
13706 }
13723 {
13729 }
13734 {
13738 }
13749 {
13752 }
13762 }
13763 }
13765 /* Helper function for outputting the checksum of a tree T. When
13766 debugging with gdb, you can "define mynext" to be "next" followed
13767 by "call debug_fold_checksum (op0)", then just trace down till the
13768 outputs differ. */
13770 void
13772 {
13787 }
13789 #endif
13791 /* Fold a unary tree expression with code CODE of type TYPE with an
13792 operand OP0. LOC is the location of the resulting expression.
13793 Return a folded expression if successful. Otherwise, return a tree
13794 expression with code CODE of type TYPE with an operand OP0. */
13796 tree
13799 {
13800 tree tem;
13801 #ifdef ENABLE_FOLD_CHECKING
13804 htab_t ht;
13811 #endif
13815 {
13818 }
13820 #ifdef ENABLE_FOLD_CHECKING
13828 #endif
13830 }
13832 /* Fold a binary tree expression with code CODE of type TYPE with
13833 operands OP0 and OP1. LOC is the location of the resulting
13834 expression. Return a folded expression if successful. Otherwise,
13835 return a tree expression with code CODE of type TYPE with operands
13836 OP0 and OP1. */
13838 tree
13841 MEM_STAT_DECL)
13842 {
13843 tree tem;
13844 #ifdef ENABLE_FOLD_CHECKING
13850 htab_t ht;
13862 #endif
13866 {
13869 }
13871 #ifdef ENABLE_FOLD_CHECKING
13887 #endif
13889 }
13891 /* Fold a ternary tree expression with code CODE of type TYPE with
13892 operands OP0, OP1, and OP2. Return a folded expression if
13893 successful. Otherwise, return a tree expression with code CODE of
13894 type TYPE with operands OP0, OP1, and OP2. */
13896 tree
13899 {
13900 tree tem;
13901 #ifdef ENABLE_FOLD_CHECKING
13909 htab_t ht;
13926 #endif
13931 {
13934 }
13936 #ifdef ENABLE_FOLD_CHECKING
13960 #endif
13962 }
13964 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13965 arguments in ARGARRAY, and a null static chain.
13966 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13967 of type TYPE from the given operands as constructed by build_call_array. */
13969 tree
13972 {
13973 tree tem;
13974 #ifdef ENABLE_FOLD_CHECKING
13980 htab_t ht;
13994 #endif
13998 #ifdef ENABLE_FOLD_CHECKING
14015 #endif
14017 }
14019 /* Perform constant folding and related simplification of initializer
14020 expression EXPR. These behave identically to "fold_buildN" but ignore
14021 potential run-time traps and exceptions that fold must preserve. */
14023 #define START_FOLD_INIT \
14024 int saved_signaling_nans = flag_signaling_nans;\
14025 int saved_trapping_math = flag_trapping_math;\
14026 int saved_rounding_math = flag_rounding_math;\
14027 int saved_trapv = flag_trapv;\
14028 int saved_folding_initializer = folding_initializer;\
14029 flag_signaling_nans = 0;\
14030 flag_trapping_math = 0;\
14031 flag_rounding_math = 0;\
14032 flag_trapv = 0;\
14033 folding_initializer = 1;
14035 #define END_FOLD_INIT \
14036 flag_signaling_nans = saved_signaling_nans;\
14037 flag_trapping_math = saved_trapping_math;\
14038 flag_rounding_math = saved_rounding_math;\
14039 flag_trapv = saved_trapv;\
14040 folding_initializer = saved_folding_initializer;
14042 tree
14045 {
14046 tree result;
14047 START_FOLD_INIT;
14051 END_FOLD_INIT;
14053 }
14055 tree
14058 {
14059 tree result;
14060 START_FOLD_INIT;
14064 END_FOLD_INIT;
14066 }
14068 tree
14071 {
14072 tree result;
14073 START_FOLD_INIT;
14077 END_FOLD_INIT;
14079 }
14081 tree
14084 {
14085 tree result;
14086 START_FOLD_INIT;
14090 END_FOLD_INIT;
14092 }
14094 #undef START_FOLD_INIT
14095 #undef END_FOLD_INIT
14097 /* Determine if first argument is a multiple of second argument. Return 0 if
14098 it is not, or we cannot easily determined it to be.
14100 An example of the sort of thing we care about (at this point; this routine
14101 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14102 fold cases do now) is discovering that
14104 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14106 is a multiple of
14108 SAVE_EXPR (J * 8)
14110 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14112 This code also handles discovering that
14114 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14116 is a multiple of 8 so we don't have to worry about dealing with a
14117 possible remainder.
14119 Note that we *look* inside a SAVE_EXPR only to determine how it was
14120 calculated; it is not safe for fold to do much of anything else with the
14121 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14122 at run time. For example, the latter example above *cannot* be implemented
14123 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14124 evaluation time of the original SAVE_EXPR is not necessarily the same at
14125 the time the new expression is evaluated. The only optimization of this
14126 sort that would be valid is changing
14128 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14130 divided by 8 to
14132 SAVE_EXPR (I) * SAVE_EXPR (J)
14134 (where the same SAVE_EXPR (J) is used in the original and the
14135 transformed version). */
14137 int
14139 {
14147 {
14149 /* Bitwise and provides a power of two multiple. If the mask is
14150 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14153 /* FALLTHRU */
14166 {
14170 /* const_binop may not detect overflow correctly,
14171 so check for it explicitly here. */
14177 size_one_node,
14181 }
14185 /* Can't handle conversions from non-integral or wider integral type. */
14191 /* .. fall through ... */
14212 }
14213 }
14215 /* Return true if CODE or TYPE is known to be non-negative. */
14217 static bool
14219 {
14222 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14223 have a signed:1 type (where the value is -1 and 0). */
14226 }
14228 /* Return true if (CODE OP0) is known to be non-negative. If the return
14229 value is based on the assumption that signed overflow is undefined,
14230 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14231 *STRICT_OVERFLOW_P. */
14233 bool
14236 {
14241 {
14243 /* We can't return 1 if flag_wrapv is set because
14244 ABS_EXPR<INT_MIN> = INT_MIN. */
14248 {
14251 }
14258 strict_overflow_p);
14261 {
14266 {
14269 strict_overflow_p);
14271 {
14275 strict_overflow_p);
14276 }
14277 }
14279 {
14282 strict_overflow_p);
14286 }
14287 }
14292 }
14294 /* We don't know sign of `t', so be conservative and return false. */
14296 }
14298 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14299 value is based on the assumption that signed overflow is undefined,
14300 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14301 *STRICT_OVERFLOW_P. */
14303 bool
14306 {
14311 {
14316 strict_overflow_p)
14318 strict_overflow_p));
14320 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14321 both unsigned and at least 2 bits shorter than the result. */
14325 {
14330 {
14334 }
14335 }
14340 {
14341 /* x * x for floating point x is always non-negative. */
14345 strict_overflow_p)
14347 strict_overflow_p));
14348 }
14350 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14351 both unsigned and their total bits is shorter than the result. */
14355 {
14374 {
14384 }
14385 }
14391 strict_overflow_p)
14393 strict_overflow_p));
14404 strict_overflow_p)
14406 strict_overflow_p));
14413 strict_overflow_p);
14416 }
14418 /* We don't know sign of `t', so be conservative and return false. */
14420 }
14422 /* Return true if T is known to be non-negative. If the return
14423 value is based on the assumption that signed overflow is undefined,
14424 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14425 *STRICT_OVERFLOW_P. */
14427 bool
14429 {
14434 {
14446 strict_overflow_p)
14448 strict_overflow_p));
14452 }
14453 /* We don't know sign of `t', so be conservative and return false. */
14455 }
14457 /* Return true if T is known to be non-negative. If the return
14458 value is based on the assumption that signed overflow is undefined,
14459 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14460 *STRICT_OVERFLOW_P. */
14462 bool
14465 {
14468 {
14486 /* Always true. */
14490 /* sqrt(-0.0) is -0.0. */
14494 strict_overflow_p);
14527 /* True if the 1st argument is nonnegative. */
14529 strict_overflow_p);
14532 /* True if the 1st OR 2nd arguments are nonnegative. */
14534 strict_overflow_p)
14536 strict_overflow_p)));
14539 /* True if the 1st AND 2nd arguments are nonnegative. */
14541 strict_overflow_p)
14543 strict_overflow_p)));
14546 /* True if the 2nd argument is nonnegative. */
14548 strict_overflow_p);
14551 /* True if the 1st argument is nonnegative or the second
14552 argument is an even integer. */
14557 strict_overflow_p);
14560 /* True if the 1st argument is nonnegative or the second
14561 argument is an even integer valued real. */
14563 {
14564 REAL_VALUE_TYPE c;
14565 HOST_WIDE_INT n;
14570 {
14571 REAL_VALUE_TYPE cint;
14576 }
14577 }
14579 strict_overflow_p);
14583 }
14585 type);
14586 }
14588 /* Return true if T is known to be non-negative. If the return
14589 value is based on the assumption that signed overflow is undefined,
14590 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14591 *STRICT_OVERFLOW_P. */
14593 bool
14595 {
14601 {
14603 {
14607 /* If the initializer is non-void, then it's a normal expression
14608 that will be assigned to the slot. */
14612 /* Otherwise, the initializer sets the slot in some way. One common
14613 way is an assignment statement at the end of the initializer. */
14615 {
14623 else
14625 }
14629 strict_overflow_p);
14632 }
14635 {
14641 arg0,
14642 arg1,
14643 strict_overflow_p);
14644 }
14648 strict_overflow_p);
14651 strict_overflow_p);
14654 strict_overflow_p);
14659 }
14661 /* We don't know sign of `t', so be conservative and return false. */
14663 }
14665 /* Return true if T is known to be non-negative. If the return
14666 value is based on the assumption that signed overflow is undefined,
14667 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14668 *STRICT_OVERFLOW_P. */
14670 bool
14672 {
14679 {
14686 strict_overflow_p);
14692 strict_overflow_p);
14701 }
14704 {
14712 strict_overflow_p);
14717 strict_overflow_p);
14730 }
14731 }
14733 /* Return true if `t' is known to be non-negative. Handle warnings
14734 about undefined signed overflow. */
14736 bool
14738 {
14745 "determining that expression is always "
14747 WARN_STRICT_OVERFLOW_MISC);
14749 }
14752 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14753 For floating point we further ensure that T is not denormal.
14754 Similar logic is present in nonzero_address in rtlanal.h.
14756 If the return value is based on the assumption that signed overflow
14757 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14758 change *STRICT_OVERFLOW_P. */
14760 bool
14763 {
14765 {
14768 strict_overflow_p);
14771 {
14777 strict_overflow_p));
14778 }
14783 strict_overflow_p);
14787 }
14790 }
14792 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14793 For floating point we further ensure that T is not denormal.
14794 Similar logic is present in nonzero_address in rtlanal.h.
14796 If the return value is based on the assumption that signed overflow
14797 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14798 change *STRICT_OVERFLOW_P. */
14800 bool
14802 tree type,
14803 tree op0,
14805 {
14808 {
14812 {
14813 /* With the presence of negative values it is hard
14814 to say something. */
14821 /* One of operands must be positive and the other non-negative. */
14822 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14823 overflows, on a twos-complement machine the sum of two
14824 nonnegative numbers can never be zero. */
14826 strict_overflow_p)
14828 strict_overflow_p));
14829 }
14834 {
14836 strict_overflow_p)
14838 strict_overflow_p))
14839 {
14842 }
14843 }
14852 {
14855 }
14862 {
14866 /* When both operands are nonzero, then MAX must be too. */
14868 strict_overflow_p))
14871 /* MAX where operand 0 is positive is positive. */
14873 strict_overflow_p);
14874 }
14875 /* MAX where operand 1 is positive is positive. */
14880 {
14884 }
14889 strict_overflow_p)
14891 strict_overflow_p));
14895 }
14898 }
14900 /* Return true when T is an address and is known to be nonzero.
14901 For floating point we further ensure that T is not denormal.
14902 Similar logic is present in nonzero_address in rtlanal.h.
14904 If the return value is based on the assumption that signed overflow
14905 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14906 change *STRICT_OVERFLOW_P. */
14908 bool
14910 {
14913 {
14918 {
14926 /* Weak declarations may link to NULL. Other things may also be NULL
14927 so protect with -fdelete-null-pointer-checks; but not variables
14928 allocated on the stack. */
14930 && (flag_delete_null_pointer_checks
14936 /* Constants are never weak. */
14941 }
14949 {
14953 }
14958 }
14960 }
14962 /* Return true when T is an address and is known to be nonzero.
14963 For floating point we further ensure that T is not denormal.
14964 Similar logic is present in nonzero_address in rtlanal.h.
14966 If the return value is based on the assumption that signed overflow
14967 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14968 change *STRICT_OVERFLOW_P. */
14970 bool
14972 {
14976 /* Doing something useful for floating point would need more work. */
14982 {
14985 strict_overflow_p);
14991 strict_overflow_p);
14999 }
15002 {
15005 strict_overflow_p);
15013 strict_overflow_p);
15028 strict_overflow_p);
15032 strict_overflow_p);
15039 }
15041 }
15043 /* Return true when T is an address and is known to be nonzero.
15044 Handle warnings about undefined signed overflow. */
15046 bool
15048 {
15055 "determining that expression is always "
15057 WARN_STRICT_OVERFLOW_MISC);
15059 }
15061 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15062 attempt to fold the expression to a constant without modifying TYPE,
15063 OP0 or OP1.
15065 If the expression could be simplified to a constant, then return
15066 the constant. If the expression would not be simplified to a
15067 constant, then return NULL_TREE. */
15069 tree
15071 {
15074 }
15076 /* Given the components of a unary expression CODE, TYPE and OP0,
15077 attempt to fold the expression to a constant without modifying
15078 TYPE or OP0.
15080 If the expression could be simplified to a constant, then return
15081 the constant. If the expression would not be simplified to a
15082 constant, then return NULL_TREE. */
15084 tree
15086 {
15089 }
15091 /* If EXP represents referencing an element in a constant string
15092 (either via pointer arithmetic or array indexing), return the
15093 tree representing the value accessed, otherwise return NULL. */
15095 tree
15097 {
15101 {
15103 tree index;
15104 tree string;
15109 else
15110 {
15114 /* Optimize the special-case of a zero lower bound.
15116 We convert the low_bound to sizetype to avoid some problems
15117 with constant folding. (E.g. suppose the lower bound is 1,
15118 and its mode is QI. Without the conversion,l (ARRAY
15119 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15120 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15126 }
15139 }
15141 }
15143 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15144 an integer constant, real, or fixed-point constant.
15146 TYPE is the type of the result. */
15148 static tree
15150 {
15154 {
15156 {
15158 HOST_WIDE_INT high;
15166 }
15173 {
15174 FIXED_VALUE_TYPE f;
15179 /* Propagate overflow flags. */
15183 }
15187 }
15190 }
15192 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15193 an integer constant or real constant.
15195 TYPE is the type of the result. */
15197 tree
15199 {
15203 {
15205 /* If the value is unsigned, then the absolute value is
15206 the same as the ordinary value. */
15209 /* Similarly, if the value is non-negative. */
15212 /* If the value is negative, then the absolute value is
15213 its negation. */
15214 else
15215 {
15217 HOST_WIDE_INT high;
15223 }
15229 else
15235 }
15238 }
15240 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15241 constant. TYPE is the type of the result. */
15243 static tree
15245 {
15255 }
15257 /* Given CODE, a relational operator, the target type, TYPE and two
15258 constant operands OP0 and OP1, return the result of the
15259 relational operation. If the result is not a compile time
15260 constant, then return NULL_TREE. */
15262 static tree
15264 {
15267 /* From here on, the only cases we handle are when the result is
15268 known to be a constant. */
15271 {
15275 /* Handle the cases where either operand is a NaN. */
15277 {
15279 {
15307 }
15310 }
15313 }
15316 {
15320 }
15322 /* Handle equality/inequality of complex constants. */
15324 {
15335 else
15337 }
15339 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15341 To compute GT, swap the arguments and do LT.
15342 To compute GE, do LT and invert the result.
15343 To compute LE, swap the arguments, do LT and invert the result.
15344 To compute NE, do EQ and invert the result.
15346 Therefore, the code below must handle only EQ and LT. */
15349 {
15354 }
15356 /* Note that it is safe to invert for real values here because we
15357 have already handled the one case that it matters. */
15361 {
15364 }
15366 /* Compute a result for LT or EQ if args permit;
15367 Otherwise return T. */
15369 {
15374 else
15376 }
15377 else
15383 }
15385 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15386 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15387 itself. */
15389 tree
15391 {
15392 /* If the expression does not have side effects then we don't have to wrap
15393 it with a cleanup point expression. */
15397 /* If the expression is a return, check to see if the expression inside the
15398 return has no side effects or the right hand side of the modify expression
15399 inside the return. If either don't have side effects set we don't need to
15400 wrap the expression in a cleanup point expression. Note we don't check the
15401 left hand side of the modify because it should always be a return decl. */
15403 {
15410 }
15413 }
15415 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15416 of an indirection through OP0, or NULL_TREE if no simplification is
15417 possible. */
15419 tree
15421 {
15423 tree subtype;
15431 {
15434 /* *&CONST_DECL -> to the value of the const decl. */
15437 /* *&p => p; make sure to handle *&"str"[cst] here. */
15439 {
15443 else
15445 }
15446 /* *(foo *)&fooarray => fooarray[0] */
15449 {
15457 }
15458 /* *(foo *)&complexfoo => __real__ complexfoo */
15462 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15465 {
15469 }
15470 }
15472 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15475 {
15478 tree op00type;
15485 {
15497 }
15498 }
15501 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15504 {
15507 tree op00type;
15514 {
15519 }
15520 }
15522 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15525 {
15526 tree type_domain;
15535 }
15538 }
15540 /* Builds an expression for an indirection through T, simplifying some
15541 cases. */
15543 tree
15545 {
15555 }
15557 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15559 tree
15561 {
15566 else
15568 }
15570 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15571 whose result is ignored. The type of the returned tree need not be
15572 the same as the original expression. */
15574 tree
15576 {
15582 {
15593 else
15599 {
15615 }
15620 }
15621 }
15623 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15624 This can only be applied to objects of a sizetype. */
15626 tree
15628 {
15635 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15636 have to do anything. Only do this when we are not given a const,
15637 because in that case, this check is more expensive than just
15638 doing it. */
15640 {
15645 }
15647 /* If divisor is a power of two, simplify this to bit manipulation. */
15649 {
15651 {
15664 {
15665 high++;
15668 }
15672 }
15673 else
15674 {
15675 tree t;
15681 }
15682 }
15683 else
15684 {
15689 }
15692 }
15694 /* Likewise, but round down. */
15696 tree
15698 {
15705 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15706 have to do anything. Only do this when we are not given a const,
15707 because in that case, this check is more expensive than just
15708 doing it. */
15710 {
15715 }
15717 /* If divisor is a power of two, simplify this to bit manipulation. */
15719 {
15720 tree t;
15724 }
15725 else
15726 {
15731 }
15734 }
15736 /* Returns the pointer to the base of the object addressed by EXP and
15737 extracts the information about the offset of the access, storing it
15738 to PBITPOS and POFFSET. */
15740 static tree
15743 {
15744 tree core;
15747 HOST_WIDE_INT bitsize;
15751 {
15756 }
15757 else
15758 {
15762 }
15765 }
15767 /* Returns true if addresses of E1 and E2 differ by a constant, false
15768 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15770 bool
15772 {
15786 {
15796 }
15798 {
15799 /* If only one of the offsets is non-constant, the difference cannot
15800 be a constant. */
15802 }
15803 else
15808 }
15810 /* Simplify the floating point expression EXP when the sign of the
15811 result is not significant. Return NULL_TREE if no simplification
15812 is possible. */
15814 tree
15816 {
15821 {
15857 {
15860 {
15862 /* Strip copysign function call, return the 1st argument. */
15868 /* Strip sign ops from the argument of "odd" math functions. */
15870 {
15874 }
15876 }
15877 }
15882 }
15884 }