| blob | cdae661733c5b4e59e93745e3529e08b5325e255 |
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. */
70 /* Nonzero if we are folding constants inside an initializer; zero
71 otherwise. */
74 /* The following constants represent a bit based encoding of GCC's
75 comparison operators. This encoding simplifies transformations
76 on relational comparison operators, such as AND and OR. */
94 };
114 HOST_WIDE_INT *,
150 /* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
151 overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
152 and SUM1. Then this yields nonzero if overflow occurred during the
153 addition.
155 Overflow occurs if A and B have the same sign, but A and SUM differ in
156 sign. Use `^' to test whether signs differ, and `< 0' to isolate the
157 sign. */
158 #define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
159 \f
160 /* If ARG2 divides ARG1 with zero remainder, carries out the division
161 of type CODE and returns the quotient.
162 Otherwise returns NULL_TREE. */
164 tree
166 {
170 /* The sign of the division is according to operand two, that
171 does the correct thing for POINTER_PLUS_EXPR where we want
172 a signed division. */
186 }
187 \f
188 /* This is nonzero if we should defer warnings about undefined
189 overflow. This facility exists because these warnings are a
190 special case. The code to estimate loop iterations does not want
191 to issue any warnings, since it works with expressions which do not
192 occur in user code. Various bits of cleanup code call fold(), but
193 only use the result if it has certain characteristics (e.g., is a
194 constant); that code only wants to issue a warning if the result is
195 used. */
199 /* If a warning about undefined overflow is deferred, this is the
200 warning. Note that this may cause us to turn two warnings into
201 one, but that is fine since it is sufficient to only give one
202 warning per expression. */
206 /* If a warning about undefined overflow is deferred, this is the
207 level at which the warning should be emitted. */
211 /* Start deferring overflow warnings. We could use a stack here to
212 permit nested calls, but at present it is not necessary. */
214 void
216 {
218 }
220 /* Stop deferring overflow warnings. If there is a pending warning,
221 and ISSUE is true, then issue the warning if appropriate. STMT is
222 the statement with which the warning should be associated (used for
223 location information); STMT may be NULL. CODE is the level of the
224 warning--a warn_strict_overflow_code value. This function will use
225 the smaller of CODE and the deferred code when deciding whether to
226 issue the warning. CODE may be zero to mean to always use the
227 deferred code. */
229 void
231 {
233 location_t locus;
238 {
244 }
255 /* Use the smallest code level when deciding to issue the
256 warning. */
265 else
268 }
270 /* Stop deferring overflow warnings, ignoring any deferred
271 warnings. */
273 void
275 {
277 }
279 /* Whether we are deferring overflow warnings. */
281 bool
283 {
285 }
287 /* This is called when we fold something based on the fact that signed
288 overflow is undefined. */
290 static void
292 {
294 {
297 {
300 }
301 }
304 }
305 \f
306 /* Return true if the built-in mathematical function specified by CODE
307 is odd, i.e. -f(x) == f(-x). */
309 static bool
311 {
313 {
347 }
349 }
351 /* Check whether we may negate an integer constant T without causing
352 overflow. */
354 bool
356 {
359 tree type;
369 {
374 }
375 else
380 }
382 /* Determine whether an expression T can be cheaply negated using
383 the function negate_expr without introducing undefined overflow. */
385 static bool
387 {
388 tree type;
397 {
402 /* Check that -CST will not overflow type. */
413 /* We want to canonicalize to positive real constants. Pretend
414 that only negative ones can be easily negated. */
432 /* -(A + B) -> (-B) - A. */
437 /* -(A + B) -> (-A) - B. */
441 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
451 /* Fall through. */
464 /* In general we can't negate A / B, because if A is INT_MIN and
465 B is 1, we may turn this into INT_MIN / -1 which is undefined
466 and actually traps on some architectures. But if overflow is
467 undefined, we can negate, because - (INT_MIN / 1) is an
468 overflow. */
476 /* Negate -((double)float) as (double)(-float). */
478 {
482 }
486 /* Negate -f(x) as f(-x). */
492 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
494 {
500 }
505 }
507 }
509 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
510 simplification is possible.
511 If negate_expr_p would return true for T, NULL_TREE will never be
512 returned. */
514 static tree
516 {
518 tree tem;
521 {
522 /* Convert - (~A) to A + 1. */
538 /* Two's complement FP formats, such as c4x, may overflow. */
548 {
557 }
579 {
580 /* -(A + B) -> (-B) - A. */
584 {
588 }
590 /* -(A + B) -> (-A) - B. */
592 {
596 }
597 }
601 /* - (A - B) -> B - A */
613 /* Fall through. */
617 {
626 }
634 /* In general we can't negate A / B, because if A is INT_MIN and
635 B is 1, we may turn this into INT_MIN / -1 which is undefined
636 and actually traps on some architectures. But if overflow is
637 undefined, we can negate, because - (INT_MIN / 1) is an
638 overflow. */
640 {
645 {
652 }
655 {
662 }
663 }
667 /* Convert -((double)float) into (double)(-float). */
669 {
673 }
677 /* Negate -f(x) as f(-x). */
680 {
686 }
690 /* Optimize -((int)x >> 31) into (unsigned)x >> 31. */
692 {
697 {
704 }
705 }
710 }
713 }
715 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
716 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
717 return NULL_TREE. */
719 static tree
721 {
723 location_t loc;
734 {
737 }
739 }
740 \f
741 /* Split a tree IN into a constant, literal and variable parts that could be
742 combined with CODE to make IN. "constant" means an expression with
743 TREE_CONSTANT but that isn't an actual constant. CODE must be a
744 commutative arithmetic operation. Store the constant part into *CONP,
745 the literal in *LITP and return the variable part. If a part isn't
746 present, set it to null. If the tree does not decompose in this way,
747 return the entire tree as the variable part and the other parts as null.
749 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
750 case, we negate an operand that was subtracted. Except if it is a
751 literal for which we use *MINUS_LITP instead.
753 If NEGATE_P is true, we are negating all of IN, again except a literal
754 for which we use *MINUS_LITP instead.
756 If IN is itself a literal or constant, return it as appropriate.
758 Note that we do not guarantee that any of the three values will be the
759 same type as IN, but they will have the same signedness and mode. */
761 static tree
764 {
771 /* Strip any conversions that don't change the machine mode or signedness. */
780 /* We can associate addition and subtraction together (even
781 though the C standard doesn't say so) for integers because
782 the value is not affected. For reals, the value might be
783 affected, so we can't. */
786 {
792 /* First see if either of the operands is a literal, then a constant. */
805 /* If we haven't dealt with either operand, this is not a case we can
806 decompose. Otherwise, VAR is either of the ones remaining, if any. */
811 else
814 /* Now do any needed negations. */
821 }
824 else
828 {
835 }
838 }
840 /* Re-associate trees split by the above function. T1 and T2 are
841 either expressions to associate or null. Return the new
842 expression, if any. LOC is the location of the new expression. If
843 we build an operation, do it in TYPE and with CODE. */
845 static tree
847 {
848 tree tem;
855 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
856 try to fold this since we will have infinite recursion. But do
857 deal with any NEGATE_EXPRs. */
860 {
862 {
871 }
873 {
876 }
881 }
885 associate_trees_exit:
888 }
889 \f
890 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
891 for use in int_const_binop, size_binop and size_diffop. */
893 static bool
895 {
902 {
911 }
916 }
919 /* Combine two integer constants ARG1 and ARG2 under operation CODE
920 to produce a new constant. Return NULL_TREE if we don't know how
921 to evaluate CODE at compile-time.
923 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
925 tree
927 {
931 HOST_WIDE_INT hi;
933 HOST_WIDE_INT garbageh;
934 tree t;
937 int is_sizetype
947 {
963 /* It's unclear from the C standard whether shifts can overflow.
964 The following code ignores overflow; perhaps a C standard
965 interpretation ruling is needed. */
994 /* This is a shortcut for a common special case. */
999 {
1005 }
1007 /* ... fall through ... */
1013 {
1016 }
1019 {
1022 }
1029 /* This is a shortcut for a common special case. */
1034 {
1039 }
1041 /* ... fall through ... */
1059 else
1065 else
1071 }
1074 {
1077 /* Propagate overflow flags ourselves. */
1080 {
1083 }
1084 }
1085 else
1091 }
1093 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1094 constant. We assume ARG1 and ARG2 have the same data type, or at least
1095 are the same kind of constant and the same machine mode. Return zero if
1096 combining the constants is not allowed in the current operating mode.
1098 If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
1100 static tree
1102 {
1103 /* Sanity check for the recursive cases. */
1114 {
1116 REAL_VALUE_TYPE d1;
1117 REAL_VALUE_TYPE d2;
1118 REAL_VALUE_TYPE value;
1119 REAL_VALUE_TYPE result;
1123 /* The following codes are handled by real_arithmetic. */
1125 {
1136 }
1144 /* Don't perform operation if we honor signaling NaNs and
1145 either operand is a NaN. */
1150 /* Don't perform operation if it would raise a division
1151 by zero exception. */
1157 /* If either operand is a NaN, just return it. Otherwise, set up
1158 for floating-point trap; we return an overflow. */
1167 /* Don't constant fold this floating point operation if
1168 the result has overflowed and flag_trapping_math. */
1176 /* Don't constant fold this floating point operation if the
1177 result may dependent upon the run-time rounding mode and
1178 flag_rounding_math is set, or if GCC's software emulation
1179 is unable to accurately represent the result. */
1189 }
1192 {
1193 FIXED_VALUE_TYPE f1;
1194 FIXED_VALUE_TYPE f2;
1195 FIXED_VALUE_TYPE result;
1200 /* The following codes are handled by fixed_arithmetic. */
1202 {
1219 }
1226 /* Propagate overflow flags. */
1230 }
1233 {
1242 {
1253 mpc_mul);
1258 notrunc);
1262 notrunc);
1269 mpc_div);
1270 /* Fallthru ... */
1276 {
1277 /* Keep this algorithm in sync with
1278 tree-complex.c:expand_complex_div_straight().
1280 Expand complex division to scalars, straightforward algorithm.
1281 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1282 t = br*br + bi*bi
1283 */
1284 tree magsquared
1288 notrunc);
1289 tree t1
1293 notrunc);
1294 tree t2
1298 notrunc);
1302 }
1303 else
1304 {
1305 /* Keep this algorithm in sync with
1306 tree-complex.c:expand_complex_div_wide().
1308 Expand complex division to scalars, modified algorithm to minimize
1309 overflow with wide input ranges. */
1315 {
1316 /* In the TRUE branch, we compute
1317 ratio = br/bi;
1318 div = (br * ratio) + bi;
1319 tr = (ar * ratio) + ai;
1320 ti = (ai * ratio) - ar;
1321 tr = tr / div;
1322 ti = ti / div; */
1326 notrunc),
1327 notrunc);
1335 }
1336 else
1337 {
1338 /* In the FALSE branch, we compute
1339 ratio = d/c;
1340 divisor = (d * ratio) + c;
1341 tr = (b * ratio) + a;
1342 ti = b - (a * ratio);
1343 tr = tr / div;
1344 ti = ti / div; */
1348 notrunc),
1349 notrunc);
1358 }
1359 }
1364 }
1368 }
1371 {
1383 {
1386 /* The trailing elements can be empty and should be treated as 0 */
1389 else
1390 {
1393 }
1397 else
1398 {
1401 }
1405 /* It is possible that const_binop cannot handle the given
1406 code and return NULL_TREE */
1411 }
1413 }
1415 }
1417 /* Create a size type INT_CST node with NUMBER sign extended. KIND
1418 indicates which particular sizetype to create. */
1420 tree
1422 {
1424 }
1425 \f
1426 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1427 is a tree code. The type of the result is taken from the operands.
1428 Both must be equivalent integer types, ala int_binop_types_match_p.
1429 If the operands are constant, so is the result. */
1431 tree
1433 {
1442 /* Handle the special case of two integer constants faster. */
1444 {
1445 /* And some specific cases even faster than that. */
1447 {
1452 }
1454 {
1457 }
1459 {
1462 }
1464 /* Handle general case of two integer constants. */
1466 }
1469 }
1471 /* Given two values, either both of sizetype or both of bitsizetype,
1472 compute the difference between the two values. Return the value
1473 in signed type corresponding to the type of the operands. */
1475 tree
1477 {
1479 tree ctype;
1484 /* If the type is already signed, just do the simple thing. */
1492 else
1495 /* If either operand is not a constant, do the conversions to the signed
1496 type and subtract. The hardware will do the right thing with any
1497 overflow in the subtraction. */
1503 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1504 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1505 overflow) and negate (which can't either). Special-case a result
1506 of zero while we're here. */
1512 else
1516 MINUS_EXPR,
1518 }
1519 \f
1520 /* A subroutine of fold_convert_const handling conversions of an
1521 INTEGER_CST to another integer type. */
1523 static tree
1525 {
1526 tree t;
1528 /* Given an integer constant, make new constant with new type,
1529 appropriately sign-extended or truncated. */
1539 }
1541 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1542 to an integer type. */
1544 static tree
1546 {
1548 tree t;
1550 /* The following code implements the floating point to integer
1551 conversion rules required by the Java Language Specification,
1552 that IEEE NaNs are mapped to zero and values that overflow
1553 the target precision saturate, i.e. values greater than
1554 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1555 are mapped to INT_MIN. These semantics are allowed by the
1556 C and C++ standards that simply state that the behavior of
1557 FP-to-integer conversion is unspecified upon overflow. */
1559 double_int val;
1560 REAL_VALUE_TYPE r;
1564 {
1571 }
1573 /* If R is NaN, return zero and show we have an overflow. */
1575 {
1578 }
1580 /* See if R is less than the lower bound or greater than the
1581 upper bound. */
1584 {
1588 {
1591 }
1592 }
1595 {
1598 {
1601 {
1604 }
1605 }
1606 }
1614 }
1616 /* A subroutine of fold_convert_const handling conversions of a
1617 FIXED_CST to an integer type. */
1619 static tree
1621 {
1622 tree t;
1626 /* Right shift FIXED_CST to temp by fbit. */
1630 {
1632 HOST_BITS_PER_DOUBLE_INT,
1635 /* Left shift temp to temp_trunc by fbit. */
1637 HOST_BITS_PER_DOUBLE_INT,
1639 }
1640 else
1641 {
1644 }
1646 /* If FIXED_CST is negative, we need to round the value toward 0.
1647 By checking if the fractional bits are not zero to add 1 to temp. */
1653 /* Given a fixed-point constant, make new constant with new type,
1654 appropriately sign-extended or truncated. */
1662 }
1664 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1665 to another floating point type. */
1667 static tree
1669 {
1670 REAL_VALUE_TYPE value;
1671 tree t;
1676 /* If converting an infinity or NAN to a representation that doesn't
1677 have one, set the overflow bit so that we can produce some kind of
1678 error message at the appropriate point if necessary. It's not the
1679 most user-friendly message, but it's better than nothing. */
1686 /* Regular overflow, conversion produced an infinity in a mode that
1687 can't represent them. */
1692 else
1695 }
1697 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1698 to a floating point type. */
1700 static tree
1702 {
1703 REAL_VALUE_TYPE value;
1704 tree t;
1711 }
1713 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1714 to another fixed-point type. */
1716 static tree
1718 {
1719 FIXED_VALUE_TYPE value;
1720 tree t;
1727 /* Propagate overflow flags. */
1731 }
1733 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
1734 to a fixed-point type. */
1736 static tree
1738 {
1739 FIXED_VALUE_TYPE value;
1740 tree t;
1749 /* Propagate overflow flags. */
1753 }
1755 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1756 to a fixed-point type. */
1758 static tree
1760 {
1761 FIXED_VALUE_TYPE value;
1762 tree t;
1770 /* Propagate overflow flags. */
1774 }
1776 /* Attempt to fold type conversion operation CODE of expression ARG1 to
1777 type TYPE. If no simplification can be done return NULL_TREE. */
1779 static tree
1781 {
1787 {
1794 }
1796 {
1803 }
1805 {
1812 }
1814 }
1816 /* Construct a vector of zero elements of vector type TYPE. */
1818 static tree
1820 {
1831 }
1833 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
1835 bool
1837 {
1852 {
1871 }
1872 }
1874 /* Convert expression ARG to type TYPE. Used by the middle-end for
1875 simple conversions in preference to calling the front-end's convert. */
1877 tree
1879 {
1881 tree tem;
1895 {
1898 /* Handle conversions between pointers to different address spaces. */
1903 /* fall through */
1908 {
1912 }
1926 {
1930 }
1932 {
1936 }
1938 {
1942 }
1945 {
1963 }
1968 {
1972 }
1975 {
1989 }
1993 {
2002 integer_zero_node));
2004 {
2008 {
2014 }
2022 }
2026 }
2044 }
2045 fold_convert_exit:
2048 }
2049 \f
2050 /* Return false if expr can be assumed not to be an lvalue, true
2051 otherwise. */
2053 static bool
2055 {
2056 /* We only need to wrap lvalue tree codes. */
2058 {
2090 /* Assume the worst for front-end tree codes. */
2094 }
2097 }
2099 /* Return an expr equal to X but certainly not valid as an lvalue. */
2101 tree
2103 {
2104 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2105 us. */
2114 }
2116 /* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
2117 Zero means allow extended lvalues. */
2121 /* When pedantic, return an expr equal to X but certainly not valid as a
2122 pedantic lvalue. Otherwise, return X. */
2124 static tree
2126 {
2131 }
2132 \f
2133 /* Given a tree comparison code, return the code that is the logical inverse
2134 of the given code. It is not safe to do this for floating-point
2135 comparisons, except for NE_EXPR and EQ_EXPR, so we receive a machine mode
2136 as well: if reversing the comparison is unsafe, return ERROR_MARK. */
2138 enum tree_code
2140 {
2145 {
2176 }
2177 }
2179 /* Similar, but return the comparison that results if the operands are
2180 swapped. This is safe for floating-point. */
2182 enum tree_code
2184 {
2186 {
2212 }
2213 }
2216 /* Convert a comparison tree code from an enum tree_code representation
2217 into a compcode bit-based encoding. This function is the inverse of
2218 compcode_to_comparison. */
2220 static enum comparison_code
2222 {
2224 {
2255 }
2256 }
2258 /* Convert a compcode bit-based encoding of a comparison operator back
2259 to GCC's enum tree_code representation. This function is the
2260 inverse of comparison_to_compcode. */
2262 static enum tree_code
2264 {
2266 {
2297 }
2298 }
2300 /* Return a tree for the comparison which is the combination of
2301 doing the AND or OR (depending on CODE) of the two operations LCODE
2302 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2303 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2304 if this makes the transformation invalid. */
2306 tree
2311 {
2318 {
2329 }
2332 {
2333 /* Eliminate unordered comparisons, as well as LTGT and ORD
2334 which are not used unless the mode has NaNs. */
2340 }
2342 {
2343 /* Check that the original operation and the optimized ones will trap
2344 under the same condition. */
2355 /* In a short-circuited boolean expression the LHS might be
2356 such that the RHS, if evaluated, will never trap. For
2357 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2358 if neither x nor y is NaN. (This is a mixed blessing: for
2359 example, the expression above will never trap, hence
2360 optimizing it to x < y would be invalid). */
2365 /* If the comparison was short-circuited, and only the RHS
2366 trapped, we may now generate a spurious trap. */
2371 /* If we changed the conditions that cause a trap, we lose. */
2374 }
2380 else
2381 {
2386 }
2387 }
2388 \f
2389 /* Return nonzero if two operands (typically of the same tree node)
2390 are necessarily equal. If either argument has side-effects this
2391 function returns zero. FLAGS modifies behavior as follows:
2393 If OEP_ONLY_CONST is set, only return nonzero for constants.
2394 This function tests whether the operands are indistinguishable;
2395 it does not test whether they are equal using C's == operation.
2396 The distinction is important for IEEE floating point, because
2397 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2398 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2400 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2401 even though it may hold multiple values during a function.
2402 This is because a GCC tree node guarantees that nothing else is
2403 executed between the evaluation of its "operands" (which may often
2404 be evaluated in arbitrary order). Hence if the operands themselves
2405 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2406 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2407 unset means assuming isochronic (or instantaneous) tree equivalence.
2408 Unless comparing arbitrary expression trees, such as from different
2409 statements, this flag can usually be left unset.
2411 If OEP_PURE_SAME is set, then pure functions with identical arguments
2412 are considered the same. It is used when the caller has other ways
2413 to ensure that global memory is unchanged in between. */
2415 int
2417 {
2418 /* If either is ERROR_MARK, they aren't equal. */
2424 /* Similar, if either does not have a type (like a released SSA name),
2425 they aren't equal. */
2429 /* Check equality of integer constants before bailing out due to
2430 precision differences. */
2434 /* If both types don't have the same signedness, then we can't consider
2435 them equal. We must check this before the STRIP_NOPS calls
2436 because they may change the signedness of the arguments. As pointers
2437 strictly don't have a signedness, require either two pointers or
2438 two non-pointers as well. */
2443 /* We cannot consider pointers to different address space equal. */
2449 /* If both types don't have the same precision, then it is not safe
2450 to strip NOPs. */
2457 /* In case both args are comparisons but with different comparison
2458 code, try to swap the comparison operands of one arg to produce
2459 a match and compare that variant. */
2463 {
2471 }
2474 /* This is needed for conversions and for COMPONENT_REF.
2475 Might as well play it safe and always test this. */
2481 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2482 We don't care about side effects in that case because the SAVE_EXPR
2483 takes care of that for us. In all other cases, two expressions are
2484 equal if they have no side effects. If we have two identical
2485 expressions with side effects that should be treated the same due
2486 to the only side effects being identical SAVE_EXPR's, that will
2487 be detected in the recursive calls below. */
2493 /* Next handle constant cases, those for which we can return 1 even
2494 if ONLY_CONST is set. */
2497 {
2512 {
2513 /* If we do not distinguish between signed and unsigned zero,
2514 consider them equal. */
2517 }
2521 {
2527 {
2529 flags))
2533 }
2536 }
2540 flags)
2542 flags));
2555 }
2560 /* Define macros to test an operand from arg0 and arg1 for equality and a
2561 variant that allows null and views null as being different from any
2562 non-null value. In the latter case, if either is null, the both
2563 must be; otherwise, do the normal comparison. */
2564 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2565 TREE_OPERAND (arg1, N), flags)
2567 #define OP_SAME_WITH_NULL(N) \
2568 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2569 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2572 {
2574 /* Two conversions are equal only if signedness and modes match. */
2576 {
2577 CASE_CONVERT:
2585 }
2595 /* For commutative ops, allow the other order. */
2603 /* If either of the pointer (or reference) expressions we are
2604 dereferencing contain a side effect, these cannot be equal. */
2610 {
2620 /* Operands 2 and 3 may be null.
2621 Compare the array index by value if it is constant first as we
2622 may have different types but same value here. */
2631 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
2632 may be NULL when we're called to compare MEM_EXPRs. */
2642 }
2646 {
2661 /* Otherwise take into account this is a commutative operation. */
2672 }
2676 {
2678 /* If the CALL_EXPRs call different functions, then they
2679 clearly can not be equal. */
2681 flags))
2684 {
2688 else
2692 }
2694 /* Now see if all the arguments are the same. */
2695 {
2706 /* If we get here and both argument lists are exhausted
2707 then the CALL_EXPRs are equal. */
2709 }
2712 }
2715 /* Consider __builtin_sqrt equal to sqrt. */
2723 }
2725 #undef OP_SAME
2726 #undef OP_SAME_WITH_NULL
2727 }
2728 \f
2729 /* Similar to operand_equal_p, but see if ARG0 might have been made by
2730 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
2732 When in doubt, return 0. */
2734 static int
2736 {
2748 /* Discard any conversions that don't change the modes of ARG0 and ARG1
2749 and see if the inner values are the same. This removes any
2750 signedness comparison, which doesn't matter here. */
2757 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
2758 actual comparison operand, ARG0.
2760 First throw away any conversions to wider types
2761 already present in the operands. */
2770 {
2773 /* Make sure shorter operand is extended the right way
2774 to match the longer operand. */
2780 }
2783 }
2784 \f
2785 /* See if ARG is an expression that is either a comparison or is performing
2786 arithmetic on comparisons. The comparisons must only be comparing
2787 two different values, which will be stored in *CVAL1 and *CVAL2; if
2788 they are nonzero it means that some operands have already been found.
2789 No variables may be used anywhere else in the expression except in the
2790 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2791 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2793 If this is true, return 1. Otherwise, return zero. */
2795 static int
2797 {
2801 /* We can handle some of the tcc_expression cases here. */
2811 {
2812 /* If we've already found a CVAL1 or CVAL2, this expression is
2813 two complex to handle. */
2819 }
2822 {
2845 /* First see if we can handle the first operand, then the second. For
2846 the second operand, we know *CVAL1 can't be zero. It must be that
2847 one side of the comparison is each of the values; test for the
2848 case where this isn't true by failing if the two operands
2849 are the same. */
2858 ;
2862 ;
2863 else
2867 ;
2871 ;
2872 else
2879 }
2880 }
2881 \f
2882 /* ARG is a tree that is known to contain just arithmetic operations and
2883 comparisons. Evaluate the operations in the tree substituting NEW0 for
2884 any occurrence of OLD0 as an operand of a comparison and likewise for
2885 NEW1 and OLD1. */
2887 static tree
2890 {
2895 /* We can handle some of the tcc_expression cases here. */
2903 {
2918 {
2937 }
2938 /* Fall through - ??? */
2941 {
2945 /* We need to check both for exact equality and tree equality. The
2946 former will be true if the operand has a side-effect. In that
2947 case, we know the operand occurred exactly once. */
2960 }
2964 }
2965 }
2966 \f
2967 /* Return a tree for the case when the result of an expression is RESULT
2968 converted to TYPE and OMITTED was previously an operand of the expression
2969 but is now not needed (e.g., we folded OMITTED * 0).
2971 If OMITTED has side effects, we must evaluate it. Otherwise, just do
2972 the conversion of RESULT to TYPE. */
2974 tree
2976 {
2979 /* If the resulting operand is an empty statement, just return the omitted
2980 statement casted to void. */
2982 {
2985 }
2988 {
2991 }
2995 omit_one_operand_exit:
2998 }
3000 /* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
3002 static tree
3004 tree omitted)
3005 {
3008 /* If the resulting operand is an empty statement, just return the omitted
3009 statement casted to void. */
3011 {
3014 }
3017 {
3020 }
3024 pedantic_omit_one_operand_exit:
3027 }
3029 /* Return a tree for the case when the result of an expression is RESULT
3030 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3031 of the expression but are now not needed.
3033 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3034 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3035 evaluated before OMITTED2. Otherwise, if neither has side effects,
3036 just do the conversion of RESULT to TYPE. */
3038 tree
3041 {
3045 {
3048 }
3050 {
3053 }
3056 }
3058 \f
3059 /* Return a simplified tree node for the truth-negation of ARG. This
3060 never alters ARG itself. We assume that ARG is an operation that
3061 returns a truth value (0 or 1).
3063 FIXME: one would think we would fold the result, but it causes
3064 problems with the dominator optimizer. */
3066 tree
3068 {
3073 /* If this is a comparison, we can simply invert it, except for
3074 floating-point non-equality comparisons, in which case we just
3075 enclose a TRUTH_NOT_EXPR around what we have. */
3078 {
3081 && flag_trapping_math
3093 }
3096 {
3125 /* Here we can invert either operand. We invert the first operand
3126 unless the second operand is a TRUTH_NOT_EXPR in which case our
3127 result is the XOR of the first operand with the inside of the
3128 negation of the second operand. */
3133 else
3167 {
3178 /* A COND_EXPR may have a throw as one operand, which
3179 then has void type. Just leave void operands
3180 as they are. */
3187 }
3204 CASE_CONVERT:
3206 {
3209 }
3211 /* ... fall through ... */
3242 }
3248 }
3250 /* Return a simplified tree node for the truth-negation of ARG. This
3251 never alters ARG itself. We assume that ARG is an operation that
3252 returns a truth value (0 or 1).
3254 FIXME: one would think we would fold the result, but it causes
3255 problems with the dominator optimizer. */
3257 tree
3259 {
3260 tree tem;
3267 {
3270 }
3273 }
3275 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3276 operands are another bit-wise operation with a common input. If so,
3277 distribute the bit operations to save an operation and possibly two if
3278 constants are involved. For example, convert
3279 (A | B) & (A | C) into A | (B & C)
3280 Further simplification will occur if B and C are constants.
3282 If this optimization cannot be done, 0 will be returned. */
3284 static tree
3287 {
3288 tree common;
3298 {
3302 }
3304 {
3308 }
3310 {
3314 }
3316 {
3320 }
3321 else
3329 }
3331 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3332 with code CODE. This optimization is unsafe. */
3333 static tree
3336 {
3340 /* (A / C) +- (B / C) -> (A +- B) / C. */
3350 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3355 {
3367 }
3370 }
3371 \f
3372 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3373 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3375 static tree
3378 {
3382 {
3389 }
3404 }
3406 /* Optimize a bit-field compare.
3408 There are two cases: First is a compare against a constant and the
3409 second is a comparison of two items where the fields are at the same
3410 bit position relative to the start of a chunk (byte, halfword, word)
3411 large enough to contain it. In these cases we can avoid the shift
3412 implicit in bitfield extractions.
3414 For constants, we emit a compare of the shifted constant with the
3415 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3416 compared. For two fields at the same position, we do the ANDs with the
3417 similar mask and compare the result of the ANDs.
3419 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3420 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3421 are the left and right operands of the comparison, respectively.
3423 If the optimization described above can be done, we return the resulting
3424 tree. Otherwise we return zero. */
3426 static tree
3429 {
3438 tree mask;
3439 tree offset;
3441 /* Get all the information about the extractions being done. If the bit size
3442 if the same as the size of the underlying object, we aren't doing an
3443 extraction at all and so can do nothing. We also don't want to
3444 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3445 then will no longer be able to replace it. */
3453 {
3454 /* If this is not a constant, we can only do something if bit positions,
3455 sizes, and signedness are the same. */
3463 }
3465 /* See if we can find a mode to refer to this field. We should be able to,
3466 but fail if we can't. */
3475 /* Set signed and unsigned types of the precision of this mode for the
3476 shifts below. */
3480 /* Compute the bit position and size for the new reference and our offset
3481 within it. If the new reference is the same size as the original, we
3482 won't optimize anything, so return zero. */
3492 /* Make the mask to be used against the extracted field. */
3499 /* If not comparing with constant, just rework the comparison
3500 and return. */
3504 unsigned_type,
3507 mask),
3510 unsigned_type,
3513 mask));
3515 /* Otherwise, we are handling the constant case. See if the constant is too
3516 big for the field. Warn and return a tree of for 0 (false) if so. We do
3517 this not only for its own sake, but to avoid having to test for this
3518 error case below. If we didn't, we might generate wrong code.
3520 For unsigned fields, the constant shifted right by the field length should
3521 be all zero. For signed fields, the high-order bits should agree with
3522 the sign bit. */
3525 {
3530 {
3534 }
3535 }
3536 else
3537 {
3542 {
3546 }
3547 }
3549 /* Single-bit compares should always be against zero. */
3551 {
3554 }
3556 /* Make a new bitfield reference, shift the constant over the
3557 appropriate number of bits and mask it with the computed mask
3558 (in case this was a signed field). If we changed it, make a new one. */
3561 {
3564 }
3574 rhs);
3577 }
3578 \f
3579 /* Subroutine for fold_truthop: decode a field reference.
3581 If EXP is a comparison reference, we return the innermost reference.
3583 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3584 set to the starting bit number.
3586 If the innermost field can be completely contained in a mode-sized
3587 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3589 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3590 otherwise it is not changed.
3592 *PUNSIGNEDP is set to the signedness of the field.
3594 *PMASK is set to the mask used. This is either contained in a
3595 BIT_AND_EXPR or derived from the width of the field.
3597 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3599 Return 0 if this is not a component reference or is one that we can't
3600 do anything with. */
3602 static tree
3607 {
3611 tree unsigned_type;
3614 /* All the optimizations using this function assume integer fields.
3615 There are problems with FP fields since the type_for_size call
3616 below can fail for, e.g., XFmode. */
3620 /* We are interested in the bare arrangement of bits, so strip everything
3621 that doesn't affect the machine mode. However, record the type of the
3622 outermost expression if it may matter below. */
3629 {
3635 }
3644 /* If the number of bits in the reference is the same as the bitsize of
3645 the outer type, then the outer type gives the signedness. Otherwise
3646 (in case of a small bitfield) the signedness is unchanged. */
3650 /* Compute the mask to access the bitfield. */
3659 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3667 }
3669 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
3670 bit positions. */
3672 static int
3674 {
3677 tree tmask;
3681 return
3688 }
3690 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3691 represents the sign bit of EXP's type. If EXP represents a sign
3692 or zero extension, also test VAL against the unextended type.
3693 The return value is the (sub)expression whose sign bit is VAL,
3694 or NULL_TREE otherwise. */
3696 static tree
3698 {
3702 tree t;
3704 /* Tree EXP must have an integral type. */
3709 /* Tree VAL must be an integer constant. */
3716 {
3723 }
3724 else
3725 {
3732 }
3734 /* We mask off those bits beyond TREE_TYPE (exp) so that we can
3735 treat VAL as if it were unsigned. */
3740 /* Handle extension from a narrower type. */
3746 }
3748 /* Subroutine for fold_truthop: determine if an operand is simple enough
3749 to be evaluated unconditionally. */
3751 static int
3753 {
3754 /* Strip any conversions that don't change the machine mode. */
3763 /* Don't regard global variables as simple. They may be
3764 allocated in ways unknown to the compiler (shared memory,
3765 #pragma weak, etc). */
3768 /* Loading a static variable is unduly expensive, but global
3769 registers aren't expensive. */
3771 }
3772 \f
3773 /* The following functions are subroutines to fold_range_test and allow it to
3774 try to change a logical combination of comparisons into a range test.
3776 For example, both
3777 X == 2 || X == 3 || X == 4 || X == 5
3778 and
3779 X >= 2 && X <= 5
3780 are converted to
3781 (unsigned) (X - 2) <= 3
3783 We describe each set of comparisons as being either inside or outside
3784 a range, using a variable named like IN_P, and then describe the
3785 range with a lower and upper bound. If one of the bounds is omitted,
3786 it represents either the highest or lowest value of the type.
3788 In the comments below, we represent a range by two numbers in brackets
3789 preceded by a "+" to designate being inside that range, or a "-" to
3790 designate being outside that range, so the condition can be inverted by
3791 flipping the prefix. An omitted bound is represented by a "-". For
3792 example, "- [-, 10]" means being outside the range starting at the lowest
3793 possible value and ending at 10, in other words, being greater than 10.
3794 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
3795 always false.
3797 We set up things so that the missing bounds are handled in a consistent
3798 manner so neither a missing bound nor "true" and "false" need to be
3799 handled using a special case. */
3801 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
3802 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
3803 and UPPER1_P are nonzero if the respective argument is an upper bound
3804 and zero for a lower. TYPE, if nonzero, is the type of the result; it
3805 must be specified for a comparison. ARG1 will be converted to ARG0's
3806 type if both are specified. */
3808 static tree
3811 {
3812 tree tem;
3816 /* If neither arg represents infinity, do the normal operation.
3817 Else, if not a comparison, return infinity. Else handle the special
3818 comparison rules. Note that most of the cases below won't occur, but
3819 are handled for consistency. */
3822 {
3827 }
3832 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
3833 for neither. In real maths, we cannot assume open ended ranges are
3834 the same. But, this is computer arithmetic, where numbers are finite.
3835 We can therefore make the transformation of any unbounded range with
3836 the value Z, Z being greater than any representable number. This permits
3837 us to treat unbounded ranges as equal. */
3841 {
3862 }
3865 }
3866 \f
3867 /* Given EXP, a logical expression, set the range it is testing into
3868 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
3869 actually being tested. *PLOW and *PHIGH will be made of the same
3870 type as the returned expression. If EXP is not a comparison, we
3871 will most likely not be returning a useful value and range. Set
3872 *STRICT_OVERFLOW_P to true if the return value is only valid
3873 because signed overflow is undefined; otherwise, do not change
3874 *STRICT_OVERFLOW_P. */
3876 tree
3879 {
3887 /* Start with simply saying "EXP != 0" and then look at the code of EXP
3888 and see if we can refine the range. Some of the cases below may not
3889 happen, but it doesn't seem worth worrying about this. We "continue"
3890 the outer loop when we've changed something; otherwise we "break"
3891 the switch, which will "break" the while. */
3897 {
3902 {
3914 }
3917 {
3924 /* We can only do something if the range is testing for zero
3925 and if the second operand is an integer constant. Note that
3926 saying something is "in" the range we make is done by
3927 complementing IN_P since it will set in the initial case of
3928 being not equal to zero; "out" is leaving it alone. */
3935 {
3956 }
3958 /* If this is an unsigned comparison, we also know that EXP is
3959 greater than or equal to zero. We base the range tests we make
3960 on that fact, so we record it here so we can parse existing
3961 range tests. We test arg0_type since often the return type
3962 of, e.g. EQ_EXPR, is boolean. */
3964 {
3968 NULL_TREE))
3973 /* If the high bound is missing, but we have a nonzero low
3974 bound, reverse the range so it goes from zero to the low bound
3975 minus 1. */
3977 {
3982 }
3983 }
3989 /* (-x) IN [a,b] -> x in [-b, -a] */
4001 /* ~ X -> -X - 1 */
4011 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4012 move a constant to the other side. */
4017 /* If EXP is signed, any overflow in the computation is undefined,
4018 so we don't worry about it so long as our computations on
4019 the bounds don't overflow. For unsigned, overflow is defined
4020 and this is exactly the right thing. */
4032 /* Check for an unsigned range which has wrapped around the maximum
4033 value thus making n_high < n_low, and normalize it. */
4035 {
4041 /* If the range is of the form +/- [ x+1, x ], we won't
4042 be able to normalize it. But then, it represents the
4043 whole range or the empty set, so make it
4044 +/- [ -, - ]. */
4048 else
4050 }
4051 else
4075 /* If we're converting arg0 from an unsigned type, to exp,
4076 a signed type, we will be doing the comparison as unsigned.
4077 The tests above have already verified that LOW and HIGH
4078 are both positive.
4080 So we have to ensure that we will handle large unsigned
4081 values the same way that the current signed bounds treat
4082 negative values. */
4085 {
4086 tree high_positive;
4087 tree equiv_type;
4088 /* For fixed-point modes, we need to pass the saturating flag
4089 as the 2nd parameter. */
4094 else
4098 /* A range without an upper bound is, naturally, unbounded.
4099 Since convert would have cropped a very large value, use
4100 the max value for the destination type. */
4101 high_positive
4108 high_positive),
4111 /* If the low bound is specified, "and" the range with the
4112 range for which the original unsigned value will be
4113 positive. */
4115 {
4119 integer_zero_node),
4120 high_positive))
4124 }
4125 else
4126 {
4127 /* Otherwise, "or" the range with the range of the input
4128 that will be interpreted as negative. */
4132 integer_zero_node),
4133 high_positive))
4137 }
4138 }
4146 }
4149 }
4151 /* If EXP is a constant, we can evaluate whether this is true or false. */
4153 {
4160 }
4164 }
4165 \f
4166 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4167 type, TYPE, return an expression to test if EXP is in (or out of, depending
4168 on IN_P) the range. Return 0 if the test couldn't be created. */
4170 tree
4173 {
4176 #ifdef HAVE_canonicalize_funcptr_for_compare
4177 /* Disable this optimization for function pointer expressions
4178 on targets that require function pointer canonicalization. */
4183 #endif
4186 {
4192 }
4210 {
4212 {
4216 }
4218 }
4220 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4222 {
4224 HOST_WIDE_INT hi;
4229 {
4232 }
4233 else
4234 {
4237 }
4240 {
4242 {
4245 etype
4247 else
4250 }
4253 }
4254 }
4256 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4257 This requires wrap-around arithmetics for the type of the expression.
4258 First make sure that arithmetics in this type is valid, then make sure
4259 that it wraps around. */
4265 {
4268 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4269 for the type in question, as we rely on this here. */
4279 else
4281 }
4291 {
4293 {
4300 }
4302 }
4310 }
4311 \f
4312 /* Return the predecessor of VAL in its type, handling the infinite case. */
4314 static tree
4316 {
4322 else
4324 }
4326 /* Return the successor of VAL in its type, handling the infinite case. */
4328 static tree
4330 {
4336 else
4338 }
4340 /* Given two ranges, see if we can merge them into one. Return 1 if we
4341 can, 0 if we can't. Set the output range into the specified parameters. */
4343 bool
4346 {
4350 tree tem;
4360 /* Make range 0 be the range that starts first, or ends last if they
4361 start at the same value. Swap them if it isn't. */
4364 || (lowequal
4367 {
4371 }
4373 /* Now flag two cases, whether the ranges are disjoint or whether the
4374 second range is totally subsumed in the first. Note that the tests
4375 below are simplified by the ones above. */
4381 /* We now have four cases, depending on whether we are including or
4382 excluding the two ranges. */
4384 {
4385 /* If they don't overlap, the result is false. If the second range
4386 is a subset it is the result. Otherwise, the range is from the start
4387 of the second to the end of the first. */
4392 else
4394 }
4397 {
4398 /* If they don't overlap, the result is the first range. If they are
4399 equal, the result is false. If the second range is a subset of the
4400 first, and the ranges begin at the same place, we go from just after
4401 the end of the second range to the end of the first. If the second
4402 range is not a subset of the first, or if it is a subset and both
4403 ranges end at the same place, the range starts at the start of the
4404 first range and ends just before the second range.
4405 Otherwise, we can't describe this as a single range. */
4411 {
4416 {
4417 /* We are in the weird situation where high0 > high1 but
4418 high1 has no successor. Punt. */
4420 }
4421 }
4423 {
4428 {
4429 /* low0 < low1 but low1 has no predecessor. Punt. */
4431 }
4432 }
4433 else
4435 }
4438 {
4439 /* If they don't overlap, the result is the second range. If the second
4440 is a subset of the first, the result is false. Otherwise,
4441 the range starts just after the first range and ends at the
4442 end of the second. */
4447 else
4448 {
4453 {
4454 /* high1 > high0 but high0 has no successor. Punt. */
4456 }
4457 }
4458 }
4460 else
4461 {
4462 /* The case where we are excluding both ranges. Here the complex case
4463 is if they don't overlap. In that case, the only time we have a
4464 range is if they are adjacent. If the second is a subset of the
4465 first, the result is the first. Otherwise, the range to exclude
4466 starts at the beginning of the first range and ends at the end of the
4467 second. */
4469 {
4474 else
4475 {
4476 /* Canonicalize - [min, x] into - [-, x]. */
4479 {
4484 /* FALLTHROUGH */
4497 }
4499 /* Canonicalize - [x, max] into - [x, -]. */
4502 {
4507 /* FALLTHROUGH */
4522 }
4524 /* The ranges might be also adjacent between the maximum and
4525 minimum values of the given type. For
4526 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4527 return + [x + 1, y - 1]. */
4529 {
4536 }
4537 else
4539 }
4540 }
4543 else
4545 }
4549 }
4550 \f
4552 /* Subroutine of fold, looking inside expressions of the form
4553 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4554 of the COND_EXPR. This function is being used also to optimize
4555 A op B ? C : A, by reversing the comparison first.
4557 Return a folded expression whose code is not a COND_EXPR
4558 anymore, or NULL_TREE if no folding opportunity is found. */
4560 static tree
4563 {
4568 tree tem;
4573 /* If we have A op 0 ? A : -A, consider applying the following
4574 transformations:
4576 A == 0? A : -A same as -A
4577 A != 0? A : -A same as A
4578 A >= 0? A : -A same as abs (A)
4579 A > 0? A : -A same as abs (A)
4580 A <= 0? A : -A same as -abs (A)
4581 A < 0? A : -A same as -abs (A)
4583 None of these transformations work for modes with signed
4584 zeros. If A is +/-0, the first two transformations will
4585 change the sign of the result (from +0 to -0, or vice
4586 versa). The last four will fix the sign of the result,
4587 even though the original expressions could be positive or
4588 negative, depending on the sign of A.
4590 Note that all these transformations are correct if A is
4591 NaN, since the two alternatives (A and -A) are also NaNs. */
4598 /* In the case that A is of the form X-Y, '-A' (arg2) may
4599 have already been folded to Y-X, check for that. */
4607 {
4621 /* Fall through. */
4643 }
4645 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4646 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4647 both transformations are correct when A is NaN: A != 0
4648 is then true, and A == 0 is false. */
4652 {
4657 }
4659 /* Try some transformations of A op B ? A : B.
4661 A == B? A : B same as B
4662 A != B? A : B same as A
4663 A >= B? A : B same as max (A, B)
4664 A > B? A : B same as max (B, A)
4665 A <= B? A : B same as min (A, B)
4666 A < B? A : B same as min (B, A)
4668 As above, these transformations don't work in the presence
4669 of signed zeros. For example, if A and B are zeros of
4670 opposite sign, the first two transformations will change
4671 the sign of the result. In the last four, the original
4672 expressions give different results for (A=+0, B=-0) and
4673 (A=-0, B=+0), but the transformed expressions do not.
4675 The first two transformations are correct if either A or B
4676 is a NaN. In the first transformation, the condition will
4677 be false, and B will indeed be chosen. In the case of the
4678 second transformation, the condition A != B will be true,
4679 and A will be chosen.
4681 The conversions to max() and min() are not correct if B is
4682 a number and A is not. The conditions in the original
4683 expressions will be false, so all four give B. The min()
4684 and max() versions would give a NaN instead. */
4687 /* Avoid these transformations if the COND_EXPR may be used
4688 as an lvalue in the C++ front-end. PR c++/19199. */
4689 && (in_gimple_form
4694 {
4699 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4701 {
4705 }
4708 {
4717 /* In C++ a ?: expression can be an lvalue, so put the
4718 operand which will be used if they are equal first
4719 so that we can convert this back to the
4720 corresponding COND_EXPR. */
4722 {
4731 }
4738 {
4747 }
4762 }
4763 }
4765 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
4766 we might still be able to simplify this. For example,
4767 if C1 is one less or one more than C2, this might have started
4768 out as a MIN or MAX and been transformed by this function.
4769 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
4775 {
4779 /* We can replace A with C1 in this case. */
4784 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
4785 MIN_EXPR, to preserve the signedness of the comparison. */
4787 OEP_ONLY_CONST)
4791 OEP_ONLY_CONST))
4792 {
4795 arg2));
4798 }
4802 /* If C1 is C2 - 1, this is min(A, C2), with the same care
4803 as above. */
4805 OEP_ONLY_CONST)
4809 OEP_ONLY_CONST))
4810 {
4813 arg2));
4816 }
4820 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
4821 MAX_EXPR, to preserve the signedness of the comparison. */
4823 OEP_ONLY_CONST)
4827 OEP_ONLY_CONST))
4828 {
4831 arg2));
4833 }
4837 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
4839 OEP_ONLY_CONST)
4843 OEP_ONLY_CONST))
4844 {
4847 arg2));
4849 }
4855 }
4858 }
4861 \f
4862 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
4863 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
4864 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
4865 false) >= 2)
4866 #endif
4868 /* EXP is some logical combination of boolean tests. See if we can
4869 merge it into some range test. Return the new tree if so. */
4871 static tree
4874 {
4882 tree tem;
4886 /* If this is an OR operation, invert both sides; we will invert
4887 again at the end. */
4891 /* If both expressions are the same, if we can merge the ranges, and we
4892 can build the range test, return it or it inverted. If one of the
4893 ranges is always true or always false, consider it to be the same
4894 expression as the other. */
4902 {
4906 }
4908 /* On machines where the branch cost is expensive, if this is a
4909 short-circuited branch and the underlying object on both sides
4910 is the same, make a non-short-circuit operation. */
4916 {
4917 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
4918 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
4919 which cases we can't do this. */
4921 {
4927 }
4931 {
4940 {
4943 WARN_STRICT_OVERFLOW_COMPARISON);
4949 }
4950 }
4951 }
4954 }
4955 \f
4956 /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
4957 bit value. Arrange things so the extra bits will be set to zero if and
4958 only if C is signed-extended to its full width. If MASK is nonzero,
4959 it is an INTEGER_CST that should be AND'ed with the extra bits. */
4961 static tree
4963 {
4966 tree temp;
4971 /* We work by getting just the sign bit into the low-order bit, then
4972 into the high-order bit, then sign-extend. We then XOR that value
4973 with C. */
4977 /* We must use a signed type in order to get an arithmetic right shift.
4978 However, we must also avoid introducing accidental overflows, so that
4979 a subsequent call to integer_zerop will work. Hence we must
4980 do the type conversion here. At this point, the constant is either
4981 zero or one, and the conversion to a signed type can never overflow.
4982 We could get an overflow if this conversion is done anywhere else. */
4992 /* If necessary, convert the type back to match the type of C. */
4998 }
4999 \f
5000 /* Find ways of folding logical expressions of LHS and RHS:
5001 Try to merge two comparisons to the same innermost item.
5002 Look for range tests like "ch >= '0' && ch <= '9'".
5003 Look for combinations of simple terms on machines with expensive branches
5004 and evaluate the RHS unconditionally.
5006 For example, if we have p->a == 2 && p->b == 4 and we can make an
5007 object large enough to span both A and B, we can do this with a comparison
5008 against the object ANDed with the a mask.
5010 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5011 operations to do this with one comparison.
5013 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5014 function and the one above.
5016 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5017 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5019 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5020 two operands.
5022 We return the simplified tree or 0 if no optimization is possible. */
5024 static tree
5027 {
5028 /* If this is the "or" of two comparisons, we can do something if
5029 the comparisons are NE_EXPR. If this is the "and", we can do something
5030 if the comparisons are EQ_EXPR. I.e.,
5031 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5033 WANTED_CODE is this operation code. For single bit fields, we can
5034 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5035 comparison for one-bit fields. */
5057 /* Start by getting the comparison codes. Fail if anything is volatile.
5058 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5059 it were surrounded with a NE_EXPR. */
5068 {
5072 }
5075 {
5079 }
5090 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5093 {
5094 tree result;
5097 {
5102 }
5105 {
5111 }
5112 }
5117 /* If the RHS can be evaluated unconditionally and its operands are
5118 simple, it wins to evaluate the RHS unconditionally on machines
5119 with expensive branches. In this case, this isn't a comparison
5120 that can be merged. Avoid doing this if the RHS is a floating-point
5121 comparison since those can trap. */
5128 {
5129 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5135 {
5141 }
5143 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5149 {
5155 }
5158 {
5160 {
5163 }
5165 }
5166 }
5168 /* See if the comparisons can be merged. Then get all the parameters for
5169 each side. */
5193 /* It must be true that the inner operation on the lhs of each
5194 comparison must be the same if we are to be able to do anything.
5195 Then see if we have constants. If not, the same must be true for
5196 the rhs's. */
5207 else
5210 /* If either comparison code is not correct for our logical operation,
5211 fail. However, we can convert a one-bit comparison against zero into
5212 the opposite comparison against that bit being set in the field. */
5216 {
5218 {
5219 /* Make the left operand unsigned, since we are only interested
5220 in the value of one bit. Otherwise we are doing the wrong
5221 thing below. */
5224 }
5225 else
5227 }
5229 /* This is analogous to the code for l_const above. */
5231 {
5233 {
5236 }
5237 else
5239 }
5241 /* See if we can find a mode that contains both fields being compared on
5242 the left. If we can't, fail. Otherwise, update all constants and masks
5243 to be relative to a field of that size. */
5248 volatilep);
5258 {
5261 }
5269 {
5277 {
5281 }
5282 }
5284 {
5292 {
5296 }
5297 }
5299 /* If the right sides are not constant, do the same for it. Also,
5300 disallow this optimization if a size or signedness mismatch occurs
5301 between the left and right sides. */
5303 {
5306 /* Make sure the two fields on the right
5307 correspond to the left without being swapped. */
5315 volatilep);
5325 {
5328 }
5337 /* Make a mask that corresponds to both fields being compared.
5338 Do this for both items being compared. If the operands are the
5339 same size and the bits being compared are in the same position
5340 then we can do this by masking both and comparing the masked
5341 results. */
5345 {
5358 }
5360 /* There is still another way we can do something: If both pairs of
5361 fields being compared are adjacent, we may be able to make a wider
5362 field containing them both.
5364 Note that we still must mask the lhs/rhs expressions. Furthermore,
5365 the mask must be shifted to account for the shift done by
5366 make_bit_field_ref. */
5371 {
5372 tree type;
5386 /* Convert to the smaller type before masking out unwanted bits. */
5389 {
5391 {
5395 }
5397 {
5401 }
5402 }
5412 }
5415 }
5417 /* Handle the case of comparisons with constants. If there is something in
5418 common between the masks, those bits of the constants must be the same.
5419 If not, the condition is always false. Test for this to avoid generating
5420 incorrect code below. */
5425 {
5427 {
5430 }
5431 else
5432 {
5435 }
5436 }
5438 /* Construct the expression we will return. First get the component
5439 reference we will make. Unless the mask is all ones the width of
5440 that field, perform the mask operation. Then compare with the
5441 merged constant. */
5447 {
5450 }
5455 fold_truthop_exit:
5458 }
5459 \f
5460 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5461 constant. */
5463 static tree
5466 {
5469 tree comp_const;
5470 tree minmax_const;
5472 tree inner;
5483 /* If something does not permit us to optimize, return the original tree. */
5491 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5492 and GT_EXPR, doing the rest with recursive calls using logical
5493 simplifications. */
5495 {
5497 {
5498 tree tem
5505 }
5508 return
5510 optimize_minmax_comparison
5512 optimize_minmax_comparison
5517 /* MAX (X, 0) == 0 -> X <= 0 */
5521 /* MAX (X, 0) == 5 -> X == 5 */
5525 /* MAX (X, 0) == -1 -> false */
5529 /* MIN (X, 0) == 0 -> X >= 0 */
5533 /* MIN (X, 0) == 5 -> false */
5536 else
5537 /* MIN (X, 0) == -1 -> X == -1 */
5542 /* MAX (X, 0) > 0 -> X > 0
5543 MAX (X, 0) > 5 -> X > 5 */
5547 /* MAX (X, 0) > -1 -> true */
5551 /* MIN (X, 0) > 0 -> false
5552 MIN (X, 0) > 5 -> false */
5555 else
5556 /* MIN (X, 0) > -1 -> X > -1 */
5561 }
5562 }
5563 \f
5564 /* T is an integer expression that is being multiplied, divided, or taken a
5565 modulus (CODE says which and what kind of divide or modulus) by a
5566 constant C. See if we can eliminate that operation by folding it with
5567 other operations already in T. WIDE_TYPE, if non-null, is a type that
5568 should be used for the computation if wider than our type.
5570 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5571 (X * 2) + (Y * 4). We must, however, be assured that either the original
5572 expression would not overflow or that overflow is undefined for the type
5573 in the language in question.
5575 If we return a non-null expression, it is an equivalent form of the
5576 original computation, but need not be in the original type.
5578 We set *STRICT_OVERFLOW_P to true if the return values depends on
5579 signed overflow being undefined. Otherwise we do not change
5580 *STRICT_OVERFLOW_P. */
5582 static tree
5585 {
5586 /* To avoid exponential search depth, refuse to allow recursion past
5587 three levels. Beyond that (1) it's highly unlikely that we'll find
5588 something interesting and (2) we've probably processed it before
5589 when we built the inner expression. */
5592 tree ret;
5597 depth++;
5599 depth--;
5602 }
5604 static tree
5607 {
5618 /* Don't deal with constants of zero here; they confuse the code below. */
5628 /* Note that we need not handle conditional operations here since fold
5629 already handles those cases. So just do arithmetic here. */
5631 {
5633 /* For a constant, we can always simplify if we are a multiply
5634 or (for divide and modulus) if it is a multiple of our constant. */
5642 /* If op0 is an expression ... */
5648 /* ... and has wrapping overflow, and its type is smaller
5649 than ctype, then we cannot pass through as widening. */
5655 /* ... or this is a truncation (t is narrower than op0),
5656 then we cannot pass through this narrowing. */
5659 /* ... or signedness changes for division or modulus,
5660 then we cannot pass through this conversion. */
5664 /* ... or has undefined overflow while the converted to
5665 type has not, we cannot do the operation in the inner type
5666 as that would introduce undefined overflow. */
5671 /* Pass the constant down and see if we can make a simplification. If
5672 we can, replace this expression with the inner simplification for
5673 possible later conversion to our or some other type. */
5678 code == MULT_EXPR
5680 strict_overflow_p))))
5685 /* If widening the type changes it from signed to unsigned, then we
5686 must avoid building ABS_EXPR itself as unsigned. */
5688 {
5692 {
5695 }
5697 }
5698 /* If the constant is negative, we cannot simplify this. */
5701 /* FALLTHROUGH */
5709 /* If widening the type changes the signedness, then we can't perform
5710 this optimization as that changes the result. */
5714 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5720 {
5727 }
5731 /* If the second operand is constant, this is a multiplication
5732 or floor division, by a power of two, so we can treat it that
5733 way unless the multiplier or divisor overflows. Signed
5734 left-shift overflow is implementation-defined rather than
5735 undefined in C90, so do not convert signed left shift into
5736 multiplication. */
5739 /* const_binop may not detect overflow correctly,
5740 so check for it explicitly here. */
5745 size_one_node,
5750 ctype,
5752 t1),
5757 /* See if we can eliminate the operation on both sides. If we can, we
5758 can return a new PLUS or MINUS. If we can't, the only remaining
5759 cases where we can do anything are if the second operand is a
5760 constant. */
5766 /* If not multiplication, we can only do this if both operands
5767 are divisible by c. */
5770 {
5775 }
5777 /* If this was a subtraction, negate OP1 and set it to be an addition.
5778 This simplifies the logic below. */
5780 {
5782 /* If OP1 was not easily negatable, the constant may be OP0. */
5784 {
5791 }
5792 }
5797 /* If either OP1 or C are negative, this optimization is not safe for
5798 some of the division and remainder types while for others we need
5799 to change the code. */
5801 {
5809 }
5811 /* If it's a multiply or a division/modulus operation of a multiple
5812 of our constant, do the operation and verify it doesn't overflow. */
5815 {
5818 /* We allow the constant to overflow with wrapping semantics. */
5822 }
5823 else
5826 /* If we have an unsigned type is not a sizetype, we cannot widen
5827 the operation since it will change the result if the original
5828 computation overflowed. */
5834 /* If we were able to eliminate our operation from the first side,
5835 apply our operation to the second side and reform the PLUS. */
5839 /* The last case is if we are a multiply. In that case, we can
5840 apply the distributive law to commute the multiply and addition
5841 if the multiplication of the constants doesn't overflow. */
5847 op1);
5852 /* We have a special case here if we are doing something like
5853 (C * 8) % 4 since we know that's zero. */
5856 /* If the multiplication can overflow we cannot optimize this.
5857 ??? Until we can properly mark individual operations as
5858 not overflowing we need to treat sizetype special here as
5859 stor-layout relies on this opimization to make
5860 DECL_FIELD_BIT_OFFSET always a constant. */
5866 {
5869 }
5871 /* ... fall through ... */
5875 /* If we can extract our operation from the LHS, do so and return a
5876 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5877 do something only if the second operand is a constant. */
5891 /* If these are the same operation types, we can associate them
5892 assuming no overflow. */
5905 /* If these operations "cancel" each other, we have the main
5906 optimizations of this pass, which occur when either constant is a
5907 multiple of the other, in which case we replace this with either an
5908 operation or CODE or TCODE.
5910 If we have an unsigned type that is not a sizetype, we cannot do
5911 this since it will change the result if the original computation
5912 overflowed. */
5920 {
5922 {
5929 }
5931 {
5938 }
5939 }
5944 }
5947 }
5948 \f
5949 /* Return a node which has the indicated constant VALUE (either 0 or
5950 1), and is of the indicated TYPE. */
5952 tree
5954 {
5959 else
5961 }
5964 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
5965 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
5966 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
5967 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
5968 COND is the first argument to CODE; otherwise (as in the example
5969 given here), it is the second argument. TYPE is the type of the
5970 original expression. Return NULL_TREE if no simplification is
5971 possible. */
5973 static tree
5978 {
5986 {
5990 /* If this operand throws an expression, then it does not make
5991 sense to try to perform a logical or arithmetic operation
5992 involving it. */
5997 }
5998 else
5999 {
6004 }
6006 /* This transformation is only worthwhile if we don't have to wrap ARG
6007 in a SAVE_EXPR and the operation can be simplified on at least one
6008 of the branches once its pushed inside the COND_EXPR. */
6016 {
6020 else
6022 }
6024 {
6028 else
6030 }
6032 /* Check that we have simplified at least one of the branches. */
6037 }
6039 \f
6040 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6042 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6043 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6044 ADDEND is the same as X.
6046 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6047 and finite. The problematic cases are when X is zero, and its mode
6048 has signed zeros. In the case of rounding towards -infinity,
6049 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6050 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6052 bool
6054 {
6058 /* Don't allow the fold with -fsignaling-nans. */
6062 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6066 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6071 /* The mode has signed zeros, and we have to honor their sign.
6072 In this situation, there is only one case we can return true for.
6073 X - 0 is the same as X unless rounding towards -infinity is
6074 supported. */
6076 }
6078 /* Subroutine of fold() that checks comparisons of built-in math
6079 functions against real constants.
6081 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6082 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6083 is the type of the result and ARG0 and ARG1 are the operands of the
6084 comparison. ARG1 must be a TREE_REAL_CST.
6086 The function returns the constant folded tree if a simplification
6087 can be made, and NULL_TREE otherwise. */
6089 static tree
6093 {
6094 REAL_VALUE_TYPE c;
6097 {
6103 {
6104 /* sqrt(x) < y is always false, if y is negative. */
6108 /* sqrt(x) > y is always true, if y is negative and we
6109 don't care about NaNs, i.e. negative values of x. */
6113 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6116 }
6118 {
6119 REAL_VALUE_TYPE c2;
6125 {
6126 /* sqrt(x) > y is x == +Inf, when y is very large. */
6131 /* sqrt(x) > y is always false, when y is very large
6132 and we don't care about infinities. */
6134 }
6136 /* sqrt(x) > c is the same as x > c*c. */
6139 }
6141 {
6142 REAL_VALUE_TYPE c2;
6148 {
6149 /* sqrt(x) < y is always true, when y is a very large
6150 value and we don't care about NaNs or Infinities. */
6154 /* sqrt(x) < y is x != +Inf when y is very large and we
6155 don't care about NaNs. */
6160 /* sqrt(x) < y is x >= 0 when y is very large and we
6161 don't care about Infinities. */
6166 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6175 dconst0)),
6178 c2)));
6179 }
6181 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6186 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6189 {
6194 dconst0)),
6197 c2)));
6198 }
6199 }
6200 }
6203 }
6205 /* Subroutine of fold() that optimizes comparisons against Infinities,
6206 either +Inf or -Inf.
6208 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6209 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6210 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6212 The function returns the constant folded tree if a simplification
6213 can be made, and NULL_TREE otherwise. */
6215 static tree
6218 {
6220 REAL_VALUE_TYPE max;
6221 tree temp;
6226 /* For negative infinity swap the sense of the comparison. */
6232 {
6234 /* x > +Inf is always false, if with ignore sNANs. */
6240 /* x <= +Inf is always true, if we don't case about NaNs. */
6244 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6247 {
6250 }
6255 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6261 /* x < +Inf is always equal to x <= DBL_MAX. */
6267 /* x != +Inf is always equal to !(x > DBL_MAX). */
6279 }
6282 }
6284 /* Subroutine of fold() that optimizes comparisons of a division by
6285 a nonzero integer constant against an integer constant, i.e.
6286 X/C1 op C2.
6288 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6289 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6290 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6292 The function returns the constant folded tree if a simplification
6293 can be made, and NULL_TREE otherwise. */
6295 static tree
6298 {
6303 HOST_WIDE_INT hpart;
6308 /* We have to do this the hard way to detect unsigned overflow.
6309 prod = int_const_binop (MULT_EXPR, arg01, arg1, 0); */
6320 {
6325 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp, 0). */
6333 }
6335 {
6339 {
6358 }
6359 }
6360 else
6361 {
6362 /* A negative divisor reverses the relational operators. */
6368 {
6387 }
6388 }
6391 {
6412 {
6415 }
6420 {
6423 }
6428 {
6431 }
6436 {
6439 }
6444 }
6447 }
6450 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6451 equality/inequality test, then return a simplified form of the test
6452 using a sign testing. Otherwise return NULL. TYPE is the desired
6453 result type. */
6455 static tree
6458 tree result_type)
6459 {
6460 /* If this is testing a single bit, we can optimize the test. */
6464 {
6465 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6466 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6470 /* This is only a win if casting to a signed type is cheap,
6471 i.e. when arg00's type is not a partial mode. */
6474 {
6477 result_type,
6480 }
6481 }
6484 }
6486 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6487 equality/inequality test, then return a simplified form of
6488 the test using shifts and logical operations. Otherwise return
6489 NULL. TYPE is the desired result type. */
6491 tree
6494 {
6495 /* If this is testing a single bit, we can optimize the test. */
6499 {
6508 /* First, see if we can fold the single bit test into a sign-bit
6509 test. */
6511 result_type);
6515 /* Otherwise we have (A & C) != 0 where C is a single bit,
6516 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6517 Similarly for (A & C) == 0. */
6519 /* If INNER is a right shift of a constant and it plus BITNUM does
6520 not overflow, adjust BITNUM and INNER. */
6527 {
6530 }
6532 /* If we are going to be able to omit the AND below, we must do our
6533 operations as unsigned. If we must use the AND, we have a choice.
6534 Normally unsigned is faster, but for some machines signed is. */
6535 #ifdef LOAD_EXTEND_OP
6538 #else
6540 #endif
6556 /* Put the AND last so it can combine with more things. */
6559 /* Make sure to return the proper type. */
6563 }
6565 }
6567 /* Check whether we are allowed to reorder operands arg0 and arg1,
6568 such that the evaluation of arg1 occurs before arg0. */
6570 static bool
6572 {
6579 }
6581 /* Test whether it is preferable two swap two operands, ARG0 and
6582 ARG1, for example because ARG0 is an integer constant and ARG1
6583 isn't. If REORDER is true, only recommend swapping if we can
6584 evaluate the operands in reverse order. */
6586 bool
6588 {
6624 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6625 for commutative and comparison operators. Ensuring a canonical
6626 form allows the optimizers to find additional redundancies without
6627 having to explicitly check for both orderings. */
6633 /* Put SSA_NAMEs last. */
6639 /* Put variables last. */
6646 }
6648 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6649 ARG0 is extended to a wider type. */
6651 static tree
6654 {
6656 tree arg1_unw;
6665 #ifdef HAVE_canonicalize_funcptr_for_compare
6666 /* Disable this optimization if we're casting a function pointer
6667 type on targets that require function pointer canonicalization. */
6672 #endif
6679 /* If possible, express the comparison in the shorter mode. */
6699 /* If we are comparing with the integer that does not fit into the range
6700 of the shorter type, the result is known. */
6711 {
6738 }
6741 }
6743 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6744 ARG0 just the signedness is changed. */
6746 static tree
6749 {
6750 tree arg0_inner;
6760 #ifdef HAVE_canonicalize_funcptr_for_compare
6761 /* Disable this optimization if we're casting a function pointer
6762 type on targets that require function pointer canonicalization. */
6767 #endif
6787 else
6791 }
6793 /* Tries to replace &a[idx] p+ s * delta with &a[idx + delta], if s is
6794 step of the array. Reconstructs s and delta in the case of s *
6795 delta being an integer constant (and thus already folded). ADDR is
6796 the address. MULT is the multiplicative expression. If the
6797 function succeeds, the new address expression is returned.
6798 Otherwise NULL_TREE is returned. LOC is the location of the
6799 resulting expression. */
6801 static tree
6803 {
6807 tree itype;
6810 /* Strip the nops that might be added when converting op1 to sizetype. */
6813 /* Canonicalize op1 into a possibly non-constant delta
6814 and an INTEGER_CST s. */
6816 {
6823 {
6826 }
6828 {
6831 }
6832 else
6834 }
6836 {
6839 }
6840 else
6841 {
6842 /* Simulate we are delta * 1. */
6845 }
6848 {
6850 {
6851 tree domain;
6853 /* Remember if this was a multi-dimensional array. */
6867 {
6870 }
6871 else
6872 {
6873 /* Try if delta is a multiple of step. */
6878 }
6880 /* Only fold here if we can verify we do not overflow one
6881 dimension of a multi-dimensional array. */
6883 {
6884 tree tmp;
6899 }
6902 }
6903 else
6908 }
6910 /* We found the suitable array reference. So copy everything up to it,
6911 and replace the index. */
6919 {
6923 }
6931 }
6934 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6935 means A >= Y && A != MAX, but in this case we know that
6936 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6938 static tree
6940 {
6947 else
6956 {
6959 }
6961 {
6964 }
6965 else
6972 {
6973 /* Convert the pointer types into integer before taking the difference. */
6977 }
6978 else
6985 }
6987 /* Fold a sum or difference of at least one multiplication.
6988 Returns the folded tree or NULL if no simplification could be made. */
6990 static tree
6993 {
6997 /* (A * C) +- (B * C) -> (A+-B) * C.
6998 (A * C) +- A -> A * (C+-1).
6999 We are most concerned about the case where C is a constant,
7000 but other combinations show up during loop reduction. Since
7001 it is not difficult, try all four possibilities. */
7004 {
7007 }
7009 {
7012 }
7013 else
7014 {
7015 /* We cannot generate constant 1 for fract. */
7020 }
7022 {
7025 }
7027 {
7029 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7030 the purpose of this canonicalization. */
7034 {
7037 }
7038 else
7040 }
7041 else
7042 {
7043 /* We cannot generate constant 1 for fract. */
7048 }
7060 /* No identical multiplicands; see if we can find a common
7061 power-of-two factor in non-power-of-two multiplies. This
7062 can help in multi-dimensional array access. */
7065 {
7068 tree maybe_same;
7072 /* Move min of absolute values to int11. */
7075 {
7080 }
7081 else
7085 /* The remainder should not be a constant, otherwise we
7086 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7087 increased the number of multiplications necessary. */
7089 {
7097 }
7098 }
7108 }
7110 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7111 specified by EXPR into the buffer PTR of length LEN bytes.
7112 Return the number of bytes placed in the buffer, or zero
7113 upon failure. */
7115 static int
7117 {
7128 {
7132 else
7137 {
7144 else
7146 }
7147 else
7150 }
7152 }
7155 /* Subroutine of native_encode_expr. Encode the REAL_CST
7156 specified by EXPR into the buffer PTR of length LEN bytes.
7157 Return the number of bytes placed in the buffer, or zero
7158 upon failure. */
7160 static int
7162 {
7168 /* There are always 32 bits in each long, no matter the size of
7169 the hosts long. We handle floating point representations with
7170 up to 192 bits. */
7181 {
7186 {
7193 else
7195 }
7196 else
7199 }
7201 }
7203 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7204 specified by EXPR into the buffer PTR of length LEN bytes.
7205 Return the number of bytes placed in the buffer, or zero
7206 upon failure. */
7208 static int
7210 {
7212 tree part;
7223 }
7226 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7227 specified by EXPR into the buffer PTR of length LEN bytes.
7228 Return the number of bytes placed in the buffer, or zero
7229 upon failure. */
7231 static int
7233 {
7243 {
7245 {
7248 }
7249 else
7253 {
7256 }
7257 else
7258 {
7262 }
7264 }
7266 }
7269 /* Subroutine of native_encode_expr. Encode the STRING_CST
7270 specified by EXPR into the buffer PTR of length LEN bytes.
7271 Return the number of bytes placed in the buffer, or zero
7272 upon failure. */
7274 static int
7276 {
7278 HOST_WIDE_INT total_bytes;
7289 {
7293 }
7294 else
7297 }
7300 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7301 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7302 buffer PTR of length LEN bytes. Return the number of bytes
7303 placed in the buffer, or zero upon failure. */
7305 int
7307 {
7309 {
7327 }
7328 }
7331 /* Subroutine of native_interpret_expr. Interpret the contents of
7332 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7333 If the buffer cannot be interpreted, return NULL_TREE. */
7335 static tree
7337 {
7351 {
7354 {
7361 else
7363 }
7364 else
7370 else
7373 }
7376 }
7379 /* Subroutine of native_interpret_expr. Interpret the contents of
7380 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7381 If the buffer cannot be interpreted, return NULL_TREE. */
7383 static tree
7385 {
7390 /* There are always 32 bits in each long, no matter the size of
7391 the hosts long. We handle floating point representations with
7392 up to 192 bits. */
7393 REAL_VALUE_TYPE r;
7404 {
7407 {
7414 else
7416 }
7417 else
7422 }
7426 }
7429 /* Subroutine of native_interpret_expr. Interpret the contents of
7430 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7431 If the buffer cannot be interpreted, return NULL_TREE. */
7433 static tree
7435 {
7450 }
7453 /* Subroutine of native_interpret_expr. Interpret the contents of
7454 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7455 If the buffer cannot be interpreted, return NULL_TREE. */
7457 static tree
7459 {
7471 {
7476 }
7478 }
7481 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7482 the buffer PTR of length LEN as a constant of type TYPE. For
7483 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7484 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7485 return NULL_TREE. */
7487 tree
7489 {
7491 {
7508 }
7509 }
7512 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7513 TYPE at compile-time. If we're unable to perform the conversion
7514 return NULL_TREE. */
7516 static tree
7518 {
7519 /* We support up to 512-bit values (for V8DFmode). */
7523 /* Check that the host and target are sane. */
7532 }
7534 /* Build an expression for the address of T. Folds away INDIRECT_REF
7535 to avoid confusing the gimplify process. */
7537 tree
7539 {
7540 /* The size of the object is not relevant when talking about its address. */
7544 /* Note: doesn't apply to ALIGN_INDIRECT_REF */
7547 {
7551 {
7554 }
7555 }
7557 {
7562 }
7563 else
7564 {
7567 }
7570 }
7572 /* Build an expression for the address of T. */
7574 tree
7576 {
7580 }
7582 /* Fold a unary expression of code CODE and type TYPE with operand
7583 OP0. Return the folded expression if folding is successful.
7584 Otherwise, return NULL_TREE. */
7586 tree
7588 {
7589 tree tem;
7590 tree arg0;
7598 {
7601 {
7602 /* Don't use STRIP_NOPS, because signedness of argument type
7603 matters. */
7605 }
7606 else
7607 {
7608 /* Strip any conversions that don't change the mode. This
7609 is safe for every expression, except for a comparison
7610 expression because its signedness is derived from its
7611 operands.
7613 Note that this is done as an internal manipulation within
7614 the constant folder, in order to find the simplest
7615 representation of the arguments so that their form can be
7616 studied. In any cases, the appropriate type conversions
7617 should be put back in the tree that will get out of the
7618 constant folder. */
7620 }
7621 }
7624 {
7631 {
7645 /* If this was a conversion, and all we did was to move into
7646 inside the COND_EXPR, bring it back out. But leave it if
7647 it is a conversion from integer to integer and the
7648 result precision is no wider than a word since such a
7649 conversion is cheap and may be optimized away by combine,
7650 while it couldn't if it were outside the COND_EXPR. Then return
7651 so we don't get into an infinite recursion loop taking the
7652 conversion out and then back in. */
7664 && (INTEGRAL_TYPE_P
7668 {
7677 }
7679 }
7681 {
7683 {
7687 }
7691 integer_one_node),
7693 integer_zero_node));
7694 }
7695 }
7698 {
7700 /* Re-association barriers around constants and other re-association
7701 barriers can be removed. */
7707 CASE_CONVERT:
7713 /* If we have (type) (a CMP b) and type is an integral type, return
7714 new expression involving the new type. */
7719 /* Handle cases of two conversions in a row. */
7721 {
7743 /* In addition to the cases of two conversions in a row
7744 handled below, if we are converting something to its own
7745 type via an object of identical or wider precision, neither
7746 conversion is needed. */
7753 /* Likewise, if the intermediate and initial types are either both
7754 float or both integer, we don't need the middle conversion if the
7755 former is wider than the latter and doesn't change the signedness
7756 (for integers). Avoid this if the final type is a pointer since
7757 then we sometimes need the middle conversion. Likewise if the
7758 final type has a precision not equal to the size of its mode. */
7767 && ! final_ptr
7771 /* If we have a sign-extension of a zero-extended value, we can
7772 replace that by a single zero-extension. */
7778 /* Two conversions in a row are not needed unless:
7779 - some conversion is floating-point (overstrict for now), or
7780 - some conversion is a vector (overstrict for now), or
7781 - the intermediate type is narrower than both initial and
7782 final, or
7783 - the intermediate type and innermost type differ in signedness,
7784 and the outermost type is wider than the intermediate, or
7785 - the initial type is a pointer type and the precisions of the
7786 intermediate and final types differ, or
7787 - the final type is a pointer type and the precisions of the
7788 initial and intermediate types differ. */
7802 }
7804 /* Handle (T *)&A.B.C for A being of type T and B and C
7805 living at offset zero. This occurs frequently in
7806 C++ upcasting and then accessing the base. */
7810 {
7812 tree offset;
7818 /* If the reference was to a (constant) zero offset, we can use
7819 the address of the base if it has the same base type
7820 as the result type and the pointer type is unqualified. */
7827 }
7831 /* Detect assigning a bitfield. */
7833 && DECL_BIT_FIELD
7835 {
7836 /* Don't leave an assignment inside a conversion
7837 unless assigning a bitfield. */
7839 /* First do the assignment, then return converted constant. */
7845 }
7847 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7848 constants (if x has signed type, the sign bit cannot be set
7849 in c). This folds extension into the BIT_AND_EXPR.
7850 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7851 very likely don't have maximal range for their precision and this
7852 transformation effectively doesn't preserve non-maximal ranges. */
7856 {
7867 <= HOST_BITS_PER_WIDE_INT
7869 {
7876 #ifdef LOAD_EXTEND_OP
7878 && !flag_syntax_only
7881 {
7885 }
7886 #endif
7887 }
7889 {
7895 }
7896 }
7898 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7899 when one of the new casts will fold away. Conservatively we assume
7900 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7906 {
7914 }
7916 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7917 of the same precision, and X is an integer type not narrower than
7918 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7924 {
7930 }
7932 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7933 type of X and Y (integer types only). */
7938 {
7939 /* Be careful not to introduce new overflows. */
7940 tree mult_type;
7943 else
7947 {
7954 }
7955 }
7976 /* For integral conversions with the same precision or pointer
7977 conversions use a NOP_EXPR instead. */
7985 /* Strip inner integral conversions that do not change the precision. */
8009 /* Convert fabs((double)float) into (double)fabsf(float). */
8012 {
8018 targ0));
8019 }
8020 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
8026 /* Strip sign ops from argument. */
8028 {
8033 }
8040 {
8046 }
8048 {
8053 }
8063 /* Convert ~ (-A) to A - 1. */
8068 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
8077 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8092 /* Perform BIT_NOT_EXPR on each element individually. */
8094 {
8099 {
8101 {
8107 }
8108 else
8111 }
8114 }
8119 /* The argument to invert_truthvalue must have Boolean type. */
8123 /* Note that the operand of this must be an int
8124 and its values must be 0 or 1.
8125 ("true" is a fixed value perhaps depending on the language,
8126 but we don't handle values other than 1 correctly yet.) */
8141 {
8149 }
8151 {
8156 }
8158 {
8162 {
8171 }
8172 }
8184 {
8192 }
8194 {
8198 }
8200 {
8204 {
8213 }
8214 }
8218 /* Fold *&X to X if X is an lvalue. */
8220 {
8227 }
8233 }
8236 /* If the operation was a conversion do _not_ mark a resulting constant
8237 with TREE_OVERFLOW if the original constant was not. These conversions
8238 have implementation defined behavior and retaining the TREE_OVERFLOW
8239 flag here would confuse later passes such as VRP. */
8240 tree
8243 {
8252 }
8254 /* Fold a binary expression of code CODE and type TYPE with operands
8255 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8256 Return the folded expression if folding is successful. Otherwise,
8257 return NULL_TREE. */
8259 static tree
8261 {
8268 else
8271 /* MIN (MAX (a, b), b) == b. */
8276 /* MIN (MAX (b, a), b) == b. */
8282 /* MIN (a, MAX (a, b)) == a. */
8288 /* MIN (a, MAX (b, a)) == a. */
8295 }
8297 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8298 by changing CODE to reduce the magnitude of constants involved in
8299 ARG0 of the comparison.
8300 Returns a canonicalized comparison tree if a simplification was
8301 possible, otherwise returns NULL_TREE.
8302 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8303 valid if signed overflow is undefined. */
8305 static tree
8309 {
8315 /* Match A +- CST code arg1 and CST code arg1. We can change the
8316 first form only if overflow is undefined. */
8318 /* In principle pointers also have undefined overflow behavior,
8319 but that causes problems elsewhere. */
8327 /* Identify the constant in arg0 and its sign. */
8330 else
8334 /* Overflowed constants and zero will cause problems. */
8339 /* See if we can reduce the magnitude of the constant in
8340 arg0 by changing the comparison code. */
8342 {
8343 /* CST <= arg1 -> CST-1 < arg1. */
8346 /* -CST < arg1 -> -CST-1 <= arg1. */
8349 /* CST > arg1 -> CST-1 >= arg1. */
8352 /* -CST >= arg1 -> -CST-1 > arg1. */
8355 else
8357 /* arg1 code' CST' might be more canonical. */
8359 }
8360 else
8361 {
8362 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8366 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8370 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8374 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8378 else
8381 }
8383 /* Now build the constant reduced in magnitude. But not if that
8384 would produce one outside of its types range. */
8392 /* We cannot swap the comparison here as that would cause us to
8393 endlessly recurse. */
8401 /* If swapping might yield to a more canonical form, do so. */
8404 else
8406 }
8408 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8409 overflow further. Try to decrease the magnitude of constants involved
8410 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8411 and put sole constants at the second argument position.
8412 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8414 static tree
8417 {
8418 tree t;
8423 /* Try canonicalization by simplifying arg0. */
8428 {
8432 }
8434 /* Try canonicalization by simplifying arg1 using the swapped
8435 comparison. */
8443 }
8445 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8446 space. This is used to avoid issuing overflow warnings for
8447 expressions like &p->x which can not wrap. */
8449 static bool
8451 {
8462 {
8465 }
8468 else
8469 {
8472 }
8487 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8488 array. */
8490 {
8491 HOST_WIDE_INT base_size;
8496 }
8499 }
8501 /* Subroutine of fold_binary. This routine performs all of the
8502 transformations that are common to the equality/inequality
8503 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8504 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8505 fold_binary should call fold_binary. Fold a comparison with
8506 tree code CODE and type TYPE with operands OP0 and OP1. Return
8507 the folded comparison or NULL_TREE. */
8509 static tree
8512 {
8525 /* If one arg is a real or integer constant, put it last. */
8529 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 +- C1. */
8536 {
8540 tree lhs;
8547 /* If the constant operation overflowed this can be
8548 simplified as a comparison against INT_MAX/INT_MIN. */
8551 {
8555 /* Get the sign of the constant on the lhs if the
8556 operation were VARIABLE + CONST1. */
8560 /* The sign of the constant determines if we overflowed
8561 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8562 Canonicalize to the INT_MIN overflow by swapping the comparison
8563 if necessary. */
8567 /* We now can look at the canonicalized case
8568 VARIABLE + 1 CODE2 INT_MIN
8569 and decide on the result. */
8578 }
8583 {
8585 "when changing X +- C1 cmp C2 to "
8587 WARN_STRICT_OVERFLOW_COMPARISON);
8589 }
8590 }
8592 /* For comparisons of pointers we can decompose it to a compile time
8593 comparison of the base objects and the offsets into the object.
8594 This requires at least one operand being an ADDR_EXPR or a
8595 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8601 {
8608 /* Get base and offset for the access. Strip ADDR_EXPR for
8609 get_inner_reference, but put it back by stripping INDIRECT_REF
8610 off the base object if possible. indirect_baseN will be true
8611 if baseN is not an address but refers to the object itself. */
8614 {
8620 else
8622 }
8624 {
8627 }
8631 {
8637 else
8639 }
8641 {
8644 }
8646 /* A local variable can never be pointed to by
8647 the default SSA name of an incoming parameter. */
8649 && indirect_base0
8652 && !indirect_base1
8657 && indirect_base1
8660 && !indirect_base0
8664 {
8669 }
8670 /* If we have equivalent bases we might be able to simplify. */
8673 {
8674 /* We can fold this expression to a constant if the non-constant
8675 offset parts are equal. */
8683 {
8690 "occur when comparing P +- C1 with "
8692 WARN_STRICT_OVERFLOW_CONDITIONAL);
8695 {
8709 }
8710 }
8711 /* We can simplify the comparison to a comparison of the variable
8712 offset parts if the constant offset parts are equal.
8713 Be careful to use signed size type here because otherwise we
8714 mess with array offsets in the wrong way. This is possible
8715 because pointer arithmetic is restricted to retain within an
8716 object and overflow on pointer differences is undefined as of
8717 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8721 {
8722 /* By converting to signed size type we cover middle-end pointer
8723 arithmetic which operates on unsigned pointer types of size
8724 type size and ARRAY_REF offsets which are properly sign or
8725 zero extended from their type in case it is narrower than
8726 size type. */
8729 else
8733 else
8741 "occur when comparing P +- C1 with "
8743 WARN_STRICT_OVERFLOW_COMPARISON);
8746 }
8747 }
8748 /* For non-equal bases we can simplify if they are addresses
8749 of local binding decls or constants. */
8751 /* We know that !operand_equal_p (base0, base1, 0)
8752 because the if condition was false. But make
8753 sure two decls are not the same. */
8767 {
8774 }
8775 /* For equal offsets we can simplify to a comparison of the
8776 base addresses. */
8778 && (indirect_base0
8780 && (indirect_base1
8785 {
8791 }
8792 }
8794 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8795 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8796 the resulting offset is smaller in absolute value than the
8797 original one. */
8805 {
8810 tree cst;
8812 "occur when combining constants around "
8815 /* Put the constant on the side where it doesn't overflow and is
8816 of lower absolute value than before. */
8822 {
8825 variable1,
8829 }
8836 {
8841 variable2);
8842 }
8843 }
8845 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8846 signed arithmetic case. That form is created by the compiler
8847 often enough for folding it to be of value. One example is in
8848 computing loop trip counts after Operator Strength Reduction. */
8854 {
8860 /* Handle unfolded multiplication by zero. */
8865 "eliminating multiplication in comparison "
8867 WARN_STRICT_OVERFLOW_COMPARISON);
8869 /* If const1 is negative we swap the sense of the comparison. */
8874 }
8881 {
8889 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8895 /* (-a) CMP (-b) -> b CMP a */
8902 {
8903 REAL_VALUE_TYPE cst;
8906 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8913 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8914 /* a CMP (-0) -> a CMP 0 */
8919 /* x != NaN is always true, other ops are always false. */
8922 {
8925 }
8927 /* Fold comparisons against infinity. */
8930 {
8934 }
8935 }
8937 /* If this is a comparison of a real constant with a PLUS_EXPR
8938 or a MINUS_EXPR of a real constant, we can convert it into a
8939 comparison with a revised real constant as long as no overflow
8940 occurs when unsafe_math_optimizations are enabled. */
8952 /* Likewise, we can simplify a comparison of a real constant with
8953 a MINUS_EXPR whose first operand is also a real constant, i.e.
8954 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
8955 floating-point types only if -fassociative-math is set. */
8966 /* Fold comparisons against built-in math functions. */
8968 && flag_unsafe_math_optimizations
8970 {
8974 {
8978 }
8979 }
8980 }
8984 {
8985 /* If we are widening one operand of an integer comparison,
8986 see if the other operand is similarly being widened. Perhaps we
8987 can do the comparison in the narrower type. */
8992 /* Or if we are changing signedness. */
8996 }
8998 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8999 constant, we can simplify it. */
9004 {
9008 }
9010 /* Simplify comparison of something with itself. (For IEEE
9011 floating-point, we can only do some of these simplifications.) */
9013 {
9015 {
9030 /* For NE, we can only do this simplification if integer
9031 or we don't honor IEEE floating point NaNs. */
9035 /* ... fall through ... */
9041 }
9042 }
9044 /* If we are comparing an expression that just has comparisons
9045 of two integer values, arithmetic expressions of those comparisons,
9046 and constants, we can simplify it. There are only three cases
9047 to check: the two values can either be equal, the first can be
9048 greater, or the second can be greater. Fold the expression for
9049 those three values. Since each value must be 0 or 1, we have
9050 eight possibilities, each of which corresponds to the constant 0
9051 or 1 or one of the six possible comparisons.
9053 This handles common cases like (a > b) == 0 but also handles
9054 expressions like ((x > y) - (y > x)) > 0, which supposedly
9055 occur in macroized code. */
9058 {
9063 /* Don't handle degenerate cases here; they should already
9064 have been handled anyway. */
9073 {
9077 /* We can't just pass T to eval_subst in case cval1 or cval2
9078 was the same as ARG1. */
9080 tree high_result
9084 arg1);
9085 tree equal_result
9089 arg1);
9090 tree low_result
9094 arg1);
9096 /* All three of these results should be 0 or 1. Confirm they are.
9097 Then use those values to select the proper code to use. */
9102 {
9103 /* Make a 3-bit mask with the high-order bit being the
9104 value for `>', the next for '=', and the low for '<'. */
9108 {
9110 /* Always false. */
9131 /* Always true. */
9133 }
9136 {
9140 }
9142 }
9143 }
9144 }
9146 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9147 into a single range test. */
9155 {
9159 }
9161 /* Fold ~X op ~Y as Y op X. */
9164 {
9170 }
9172 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9175 {
9181 }
9184 }
9187 /* Subroutine of fold_binary. Optimize complex multiplications of the
9188 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9189 argument EXPR represents the expression "z" of type TYPE. */
9191 static tree
9193 {
9198 {
9201 }
9203 {
9206 }
9207 else
9208 {
9212 }
9221 }
9224 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9225 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9226 guarantees that P and N have the same least significant log2(M) bits.
9227 N is not otherwise constrained. In particular, N is not normalized to
9228 0 <= N < M as is common. In general, the precise value of P is unknown.
9229 M is chosen as large as possible such that constant N can be determined.
9231 Returns M and sets *RESIDUE to N.
9233 If ALLOW_FUNC_ALIGN is true, do take functions' DECL_ALIGN_UNIT into
9234 account. This is not always possible due to PR 35705.
9235 */
9237 static unsigned HOST_WIDE_INT
9240 {
9247 {
9250 {
9252 tree offset;
9260 {
9263 else
9264 /* We don't handle more complicated offset expressions. */
9266 }
9267 }
9272 }
9274 {
9282 allow_func_align);
9288 {
9291 }
9293 {
9296 {
9299 /* Compute the greatest power-of-2 divisor of op1. */
9303 /* If align is non-zero and less than *modulus, replace
9304 *modulus with align., If align is 0, then either op1 is 0
9305 or the greatest power-of-2 divisor of op1 doesn't fit in an
9306 unsigned HOST_WIDE_INT. In either case, no additional
9307 constraint is imposed. */
9312 }
9313 }
9314 }
9316 /* If we get here, we were unable to determine anything useful about the
9317 expression. */
9319 }
9322 /* Fold a binary expression of code CODE and type TYPE with operands
9323 OP0 and OP1. LOC is the location of the resulting expression.
9324 Return the folded expression if folding is successful. Otherwise,
9325 return NULL_TREE. */
9327 tree
9330 {
9344 /* Strip any conversions that don't change the mode. This is
9345 safe for every expression, except for a comparison expression
9346 because its signedness is derived from its operands. So, in
9347 the latter case, only strip conversions that don't change the
9348 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9349 preserved.
9351 Note that this is done as an internal manipulation within the
9352 constant folder, in order to find the simplest representation
9353 of the arguments so that their form can be studied. In any
9354 cases, the appropriate type conversions should be put back in
9355 the tree that will get out of the constant folder. */
9358 {
9361 }
9362 else
9363 {
9366 }
9368 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9369 constant but we can't do arithmetic on them. */
9376 {
9378 {
9379 /* Make sure type and arg0 have the same saturating flag. */
9383 }
9386 else
9390 {
9394 }
9395 }
9397 /* If this is a commutative operation, and ARG0 is a constant, move it
9398 to ARG1 to reduce the number of tests below. */
9403 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9405 First check for cases where an arithmetic operation is applied to a
9406 compound, conditional, or comparison operation. Push the arithmetic
9407 operation inside the compound or conditional to see if any folding
9408 can then be done. Convert comparison to conditional for this purpose.
9409 The also optimizes non-constant cases that used to be done in
9410 expand_expr.
9412 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9413 one of the operands is a comparison and the other is a comparison, a
9414 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9415 code below would make the expression more complex. Change it to a
9416 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9417 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9429 {
9433 boolean_type_node,
9441 }
9445 {
9447 {
9453 }
9456 {
9462 }
9465 {
9471 }
9474 {
9480 }
9481 }
9484 {
9486 /* 0 +p index -> (type)index */
9490 /* PTR +p 0 -> PTR */
9494 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9500 arg1),
9502 arg0)));
9504 /* index +p PTR -> PTR +p index */
9511 /* (PTR +p B) +p A -> PTR +p (B + A) */
9513 {
9514 tree inner;
9523 }
9525 /* PTR_CST +p CST -> CST1 */
9530 /* Try replacing &a[i1] +p c * i2 with &a[i1 + i2], if c is step
9531 of the array. Loop optimizer sometimes produce this type of
9532 expressions. */
9534 {
9539 }
9544 /* A + (-B) -> A - B */
9550 /* (-A) + B -> B - A */
9559 {
9560 /* Convert ~A + 1 to -A. */
9567 /* ~X + X is -1. */
9570 {
9575 {
9578 }
9579 }
9581 /* X + ~X is -1. */
9584 {
9589 {
9592 }
9593 }
9595 /* X + (X / CST) * -CST is X % CST. */
9600 {
9609 cst0));
9610 }
9611 }
9613 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
9614 same or one. Make sure type is not saturating.
9615 fold_plusminus_mult_expr will re-associate. */
9620 {
9624 }
9627 {
9631 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9632 with a constant, and the two constants have no bits in common,
9633 we should treat this as a BIT_IOR_EXPR since this may produce more
9634 simplifications. */
9642 {
9645 }
9647 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9648 (plus (plus (mult) (mult)) (foo)) so that we can
9649 take advantage of the factoring cases below. */
9656 {
9662 else
9675 parg0),
9677 marg)),
9681 return
9687 parg1)));
9688 }
9689 }
9690 else
9691 {
9692 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9696 /* Likewise if the operands are reversed. */
9700 /* Convert X + -C into X - C. */
9703 {
9709 }
9711 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9712 to __complex__ ( x, y ). This is not the same for SNaNs or
9713 if signed zeros are involved. */
9717 {
9724 {
9728 {
9734 }
9736 {
9742 }
9743 }
9744 }
9752 /* Convert x+x into x*2.0. */
9758 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9759 We associate floats only if the user has specified
9760 -fassociative-math. */
9764 {
9769 {
9770 tree tree0;
9773 }
9774 }
9775 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9776 We associate floats only if the user has specified
9777 -fassociative-math. */
9781 {
9786 {
9787 tree tree0;
9790 }
9791 }
9792 }
9794 bit_rotate:
9795 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9796 is a rotate of A by C1 bits. */
9797 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9798 is a rotate of A by B bits. */
9799 {
9801 tree rtype;
9810 /* Only create rotates in complete modes. Other cases are not
9811 expanded properly. */
9813 {
9829 {
9833 code0 == LSHIFT_EXPR
9837 }
9839 {
9847 TYPE_PRECISION
9851 return
9854 ? LROTATE_EXPR
9858 }
9860 {
9868 TYPE_PRECISION
9872 return fold_convert_loc
9875 ? LROTATE_EXPR
9879 }
9880 }
9881 }
9883 associate:
9884 /* In most languages, can't associate operations on floats through
9885 parentheses. Rather than remember where the parentheses were, we
9886 don't associate floats at all, unless the user has specified
9887 -fassociative-math.
9888 And, we need to make sure type is not saturating. */
9892 {
9897 /* Split both trees into variables, constants, and literals. Then
9898 associate each group together, the constants with literals,
9899 then the result with variables. This increases the chances of
9900 literals being recombined later and of generating relocatable
9901 expressions for the sum of a constant and literal. */
9906 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9910 /* With undefined overflow we can only associate constants with one
9911 variable, and constants whose association doesn't overflow. */
9914 {
9916 {
9924 /* The only case we can still associate with two variables
9925 is if they are the same, modulo negation. */
9928 }
9931 {
9938 }
9939 }
9941 /* Only do something if we found more than two objects. Otherwise,
9942 nothing has changed and we risk infinite recursion. */
9948 {
9954 /* Preserve the MINUS_EXPR if the negative part of the literal is
9955 greater than the positive part. Otherwise, the multiplicative
9956 folding code (i.e extract_muldiv) may be fooled in case
9957 unsigned constants are subtracted, like in the following
9958 example: ((X*2 + 4) - 8U)/2. */
9960 {
9964 {
9968 }
9969 else
9970 {
9974 }
9975 }
9977 {
9979 return
9983 else
9984 {
9987 return
9991 }
9992 }
9995 return
9998 }
9999 }
10004 /* Pointer simplifications for subtraction, simple reassociations. */
10006 {
10007 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10010 {
10020 }
10021 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10023 {
10030 }
10031 }
10032 /* A - (-B) -> A + B */
10037 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10048 /* Convert -A - 1 to ~A. */
10057 /* Convert -1 - A to ~A. */
10063 /* X - (X / CST) * CST is X % CST. */
10071 return
10077 {
10083 /* Fold A - (A & B) into ~B & A. */
10086 {
10088 {
10095 }
10097 {
10104 }
10105 }
10107 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10108 any power of 2 minus 1. */
10113 {
10119 {
10123 }
10124 }
10125 }
10127 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10131 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10132 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10133 (-ARG1 + ARG0) reduces to -ARG1. */
10137 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10138 __complex__ ( x, -y ). This is not the same for SNaNs or if
10139 signed zeros are involved. */
10143 {
10150 {
10154 {
10156 arg1r ? arg1r
10161 }
10163 {
10167 arg1i ? arg1i
10170 }
10171 }
10172 }
10174 /* Fold &x - &x. This can happen from &x.foo - &x.
10175 This is unsafe for certain floats even in non-IEEE formats.
10176 In IEEE, it is unsafe because it does wrong for NaNs.
10177 Also note that operand_equal_p is always false if an operand
10178 is volatile. */
10184 /* A - B -> A + (-B) if B is easily negatable. */
10187 /* Avoid this transformation if B is a positive REAL_CST. */
10196 /* Try folding difference of addresses. */
10197 {
10198 HOST_WIDE_INT diff;
10204 }
10206 /* Fold &a[i] - &a[j] to i-j. */
10211 {
10216 {
10224 }
10225 }
10228 && flag_unsafe_math_optimizations
10234 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
10235 same or one. Make sure type is not saturating.
10236 fold_plusminus_mult_expr will re-associate. */
10241 {
10245 }
10250 /* (-A) * (-B) -> A * B */
10265 {
10270 /* Transform x * -1 into -x. Make sure to do the negation
10271 on the original operand with conversions not stripped
10272 because we can only strip non-sign-changing conversions. */
10275 /* Transform x * -C into -x * C if x is easily negatable. */
10284 tem);
10286 /* (a * (1 << b)) is (a << b) */
10296 /* (A + A) * C -> A * 2 * C */
10312 {
10315 "occur when simplifying "
10317 WARN_STRICT_OVERFLOW_MISC);
10319 }
10321 /* Optimize z * conj(z) for integer complex numbers. */
10328 }
10329 else
10330 {
10331 /* Maybe fold x * 0 to 0. The expressions aren't the same
10332 when x is NaN, since x * 0 is also NaN. Nor are they the
10333 same in modes with signed zeros, since multiplying a
10334 negative value by 0 gives -0, not +0. */
10339 /* In IEEE floating point, x*1 is not equivalent to x for snans.
10340 Likewise for complex arithmetic with signed zeros. */
10347 /* Transform x * -1.0 into -x. */
10354 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10355 the result for floating point types due to rounding so it is applied
10356 only if -fassociative-math was specify. */
10361 {
10367 }
10369 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10371 {
10374 {
10377 }
10378 }
10380 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10381 This is not the same for NaNs or if signed zeros are
10382 involved. */
10388 {
10391 return
10397 return
10402 }
10404 /* Optimize z * conj(z) for floating point complex numbers.
10405 Guarded by flag_unsafe_math_optimizations as non-finite
10406 imaginary components don't produce scalar results. */
10417 {
10421 /* Optimizations of root(...)*root(...). */
10423 {
10428 /* Optimize sqrt(x)*sqrt(x) as x. */
10434 /* Optimize root(x)*root(y) as root(x*y). */
10438 }
10440 /* Optimize expN(x)*expN(y) as expN(x+y). */
10442 {
10448 }
10450 /* Optimizations of pow(...)*pow(...). */
10454 {
10460 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10462 {
10467 }
10469 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10471 {
10476 }
10477 }
10479 /* Optimize tan(x)*cos(x) as sin(x). */
10488 {
10494 }
10496 /* Optimize x*pow(x,c) as pow(x,c+1). */
10500 {
10506 {
10508 REAL_VALUE_TYPE c;
10509 tree arg;
10515 }
10516 }
10518 /* Optimize pow(x,c)*x as pow(x,c+1). */
10522 {
10528 {
10530 REAL_VALUE_TYPE c;
10531 tree arg;
10537 }
10538 }
10540 /* Optimize x*x as pow(x,2.0), which is expanded as x*x. */
10543 {
10547 {
10550 }
10551 }
10552 }
10553 }
10557 bit_ior:
10565 /* ~X | X is -1. */
10568 {
10572 }
10574 /* X | ~X is -1. */
10577 {
10581 }
10583 /* Canonicalize (X & C1) | C2. */
10587 {
10595 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10601 {
10605 }
10606 else
10607 {
10611 }
10613 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10618 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10619 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10620 mode which allows further optimizations. */
10630 {
10631 unsigned HOST_WIDE_INT mask
10635 {
10639 }
10640 }
10647 arg1);
10648 }
10650 /* (X & Y) | Y is (X, Y). */
10654 /* (X & Y) | X is (Y, X). */
10659 /* X | (X & Y) is (Y, X). */
10664 /* X | (Y & X) is (Y, X). */
10674 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10676 This results in more efficient code for machines without a NAND
10677 instruction. Combine will canonicalize to the first form
10678 which will allow use of NAND instructions provided by the
10679 backend if they exist. */
10682 {
10683 return
10690 }
10692 /* See if this can be simplified into a rotate first. If that
10693 is unsuccessful continue in the association code. */
10704 /* ~X ^ X is -1. */
10707 {
10711 }
10713 /* X ^ ~X is -1. */
10716 {
10720 }
10722 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10723 with a constant, and the two constants have no bits in common,
10724 we should treat this as a BIT_IOR_EXPR since this may produce more
10725 simplifications. */
10733 {
10736 }
10738 /* (X | Y) ^ X -> Y & ~ X*/
10741 {
10744 arg1);
10749 }
10751 /* (Y | X) ^ X -> Y & ~ X*/
10754 {
10757 arg1);
10762 }
10764 /* X ^ (X | Y) -> Y & ~ X*/
10767 {
10770 arg0);
10775 }
10777 /* X ^ (Y | X) -> Y & ~ X*/
10780 {
10783 arg0);
10788 }
10790 /* Convert ~X ^ ~Y to X ^ Y. */
10799 /* Convert ~X ^ C to X ^ ~C. */
10807 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10814 /* Fold (X & Y) ^ Y as ~X & Y. */
10817 {
10822 }
10823 /* Fold (X & Y) ^ X as ~Y & X. */
10827 {
10832 }
10833 /* Fold X ^ (X & Y) as X & ~Y. */
10836 {
10841 }
10842 /* Fold X ^ (Y & X) as ~Y & X. */
10846 {
10851 }
10853 /* See if this can be simplified into a rotate first. If that
10854 is unsuccessful continue in the association code. */
10865 /* ~X & X is always zero. */
10870 /* X & ~X is always zero. */
10875 /* Canonicalize (X | C1) & C2 as (X & C2) | (C1 & C2). */
10879 {
10885 return
10889 }
10891 /* (X | Y) & Y is (X, Y). */
10895 /* (X | Y) & X is (Y, X). */
10900 /* X & (X | Y) is (Y, X). */
10905 /* X & (Y | X) is (Y, X). */
10911 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10915 {
10921 }
10922 /* Fold ~X & 1 as (X & 1) == 0. */
10925 {
10931 }
10933 /* Fold (X ^ Y) & Y as ~X & Y. */
10936 {
10941 }
10942 /* Fold (X ^ Y) & X as ~Y & X. */
10946 {
10951 }
10952 /* Fold X & (X ^ Y) as X & ~Y. */
10955 {
10960 }
10961 /* Fold X & (Y ^ X) as ~Y & X. */
10965 {
10970 }
10975 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10978 {
10979 unsigned int prec
10985 return
10987 }
10989 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
10991 This results in more efficient code for machines without a NOR
10992 instruction. Combine will canonicalize to the first form
10993 which will allow use of NOR instructions provided by the
10994 backend if they exist. */
10997 {
11004 }
11006 /* If arg0 is derived from the address of an object or function, we may
11007 be able to fold this expression using the object or function's
11008 alignment. */
11010 {
11017 /* This works because modulus is a power of 2. If this weren't the
11018 case, we'd have to replace it by its greatest power-of-2
11019 divisor: modulus & -modulus. */
11022 }
11024 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
11025 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
11026 if the new mask might be further optimized. */
11035 {
11037 unsigned HOST_WIDE_INT mask
11047 {
11050 /* See if more bits can be proven as zero because of
11051 zero extension. */
11054 {
11059 {
11061 /* See if we can shorten the right shift. */
11064 }
11065 }
11069 /* For arithmetic shift if sign bit could be set, zerobits
11070 can contain actually sign bits, so no transformation is
11071 possible, unless MASK masks them all away. In that
11072 case the shift needs to be converted into logical shift. */
11075 {
11078 else
11080 }
11081 }
11083 /* ((X << 16) & 0xff00) is (X, 0). */
11090 {
11093 /* Only do the transformation if NEWMASK is some integer
11094 mode's mask. */
11101 {
11102 tree newmaskt;
11105 {
11111 }
11112 else
11117 }
11118 }
11119 }
11124 /* Don't touch a floating-point divide by zero unless the mode
11125 of the constant can represent infinity. */
11131 /* Optimize A / A to 1.0 if we don't care about
11132 NaNs or Infinities. Skip the transformation
11133 for non-real operands. */
11138 {
11142 }
11144 /* The complex version of the above A / A optimization. */
11147 {
11151 {
11153 /* omit_two_operands will call fold_convert for us. */
11155 }
11156 }
11158 /* (-A) / (-B) -> A / B */
11168 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11173 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11179 /* If ARG1 is a constant, we can convert this to a multiply by the
11180 reciprocal. This does not have the same rounding properties,
11181 so only do this if -freciprocal-math. We can actually
11182 always safely do it if ARG1 is a power of two, but it's hard to
11183 tell if it is or not in a portable manner. */
11185 {
11190 /* Find the reciprocal if optimizing and the result is exact. */
11192 {
11193 REAL_VALUE_TYPE r;
11196 {
11200 }
11201 }
11202 }
11203 /* Convert A/B/C to A/(B*C). */
11210 /* Convert A/(B/C) to (A/B)*C. */
11218 /* Convert C1/(X*C2) into (C1/C2)/X. */
11223 {
11229 }
11232 {
11236 /* Optimize sin(x)/cos(x) as tan(x). */
11242 {
11247 }
11249 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11255 {
11259 {
11264 }
11265 }
11267 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11268 NaNs or Infinities. */
11272 {
11279 {
11284 }
11285 }
11287 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11288 NaNs or Infinities. */
11292 {
11299 {
11303 {
11307 tmp);
11308 }
11309 }
11310 }
11312 /* Optimize pow(x,c)/x as pow(x,c-1). */
11316 {
11322 {
11324 REAL_VALUE_TYPE c;
11325 tree arg;
11331 }
11332 }
11334 /* Optimize a/root(b/c) into a*root(c/b). */
11336 {
11340 {
11349 }
11350 }
11352 /* Optimize x/expN(y) into x*expN(-y). */
11354 {
11361 }
11363 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11367 {
11375 }
11376 }
11381 /* Simplify A / (B << N) where A and B are positive and B is
11382 a power of 2, to A >> (N + log2(B)). */
11387 {
11390 {
11397 WARN_STRICT_OVERFLOW_MISC);
11403 }
11404 }
11406 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11407 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11413 /* Fall thru */
11422 /* X / -1 is -X. */
11429 /* Convert -A / -B to A / B when the type is signed and overflow is
11430 undefined. */
11434 {
11437 "when distributing negation across "
11439 WARN_STRICT_OVERFLOW_MISC);
11445 }
11449 {
11452 "when distributing negation across "
11454 WARN_STRICT_OVERFLOW_MISC);
11460 }
11462 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11463 operation, EXACT_DIV_EXPR.
11465 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11466 At one time others generated faster code, it's not clear if they do
11467 after the last round to changes to the DIV code in expmed.c. */
11476 {
11480 WARN_STRICT_OVERFLOW_MISC);
11482 }
11490 /* X % 1 is always zero, but be sure to preserve any side
11491 effects in X. */
11495 /* X % 0, return X % 0 unchanged so that we can get the
11496 proper warnings and errors. */
11500 /* 0 % X is always zero, but be sure to preserve any side
11501 effects in X. Place this after checking for X == 0. */
11505 /* X % -1 is zero. */
11512 /* X % -C is the same as X % C. */
11519 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11526 /* X % -Y is the same as X % Y. */
11539 {
11543 WARN_STRICT_OVERFLOW_MISC);
11545 }
11547 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11548 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11552 {
11554 /* Also optimize A % (C << N) where C is a power of 2,
11555 to A & ((C << N) - 1). */
11560 {
11561 tree mask
11566 "occur when simplifying "
11568 WARN_STRICT_OVERFLOW_MISC);
11572 }
11573 }
11584 /* Optimize -1 >> x for arithmetic right shifts. */
11588 /* ... fall through ... */
11591 shift:
11597 /* Since negative shift count is not well-defined,
11598 don't try to compute it in the compiler. */
11602 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11607 {
11611 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11612 being well defined. */
11614 {
11620 else
11622 }
11626 }
11628 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11629 into x & ((unsigned)-1 >> c) for unsigned types. */
11637 {
11640 tree lshift;
11641 tree arg00;
11644 {
11651 }
11652 }
11654 /* Rewrite an LROTATE_EXPR by a constant into an
11655 RROTATE_EXPR by a new constant. */
11657 {
11662 }
11664 /* If we have a rotate of a bit operation with the rotate count and
11665 the second operand of the bit operation both constant,
11666 permute the two operations. */
11678 /* Two consecutive rotates adding up to the precision of the
11679 type can be ignored. */
11690 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11691 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11692 if the latter can be further optimized. */
11697 {
11701 arg1);
11705 arg1);
11709 }
11737 /* Note that the operands of this must be ints
11738 and their values must be 0 or 1.
11739 ("true" is a fixed value perhaps depending on the language.) */
11740 /* If first arg is constant zero, return it. */
11744 /* If either arg is constant true, drop it. */
11748 /* Preserve sequence points. */
11751 /* If second arg is constant zero, result is zero, but first arg
11752 must be evaluated. */
11755 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11756 case will be handled here. */
11760 /* !X && X is always false. */
11764 /* X && !X is always false. */
11769 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11770 means A >= Y && A != MAX, but in this case we know that
11771 A < X <= MAX. */
11775 {
11783 }
11785 truth_andor:
11786 /* We only do these simplifications if we are optimizing. */
11790 /* Check for things like (A || B) && (A || C). We can convert this
11791 to A || (B && C). Note that either operator can be any of the four
11792 truth and/or operations and the transformation will still be
11793 valid. Also note that we only care about order for the
11794 ANDIF and ORIF operators. If B contains side effects, this
11795 might change the truth-value of A. */
11802 {
11822 /* This case if tricky because we must either have commutative
11823 operators or else A10 must not have side-effects. */
11829 a01);
11830 }
11832 /* See if we can build a range comparison. */
11836 /* Check for the possibility of merging component references. If our
11837 lhs is another similar operation, try to merge its rhs with our
11838 rhs. Then try to merge our lhs and rhs. */
11850 /* Note that the operands of this must be ints
11851 and their values must be 0 or true.
11852 ("true" is a fixed value perhaps depending on the language.) */
11853 /* If first arg is constant true, return it. */
11857 /* If either arg is constant zero, drop it. */
11861 /* Preserve sequence points. */
11864 /* If second arg is constant true, result is true, but we must
11865 evaluate first arg. */
11868 /* Likewise for first arg, but note this only occurs here for
11869 TRUTH_OR_EXPR. */
11873 /* !X || X is always true. */
11877 /* X || !X is always true. */
11885 /* If the second arg is constant zero, drop it. */
11888 /* If the second arg is constant true, this is a logical inversion. */
11890 {
11891 /* Only call invert_truthvalue if operand is a truth value. */
11894 else
11897 }
11898 /* Identical arguments cancel to zero. */
11902 /* !X ^ X is always true. */
11907 /* X ^ !X is always true. */
11920 /* bool_var != 0 becomes bool_var. */
11925 /* bool_var == 1 becomes bool_var. */
11930 /* bool_var != 1 becomes !bool_var. */
11936 /* bool_var == 0 becomes !bool_var. */
11942 /* !exp != 0 becomes !exp */
11947 /* If this is an equality comparison of the address of two non-weak,
11948 unaliased symbols neither of which are extern (since we do not
11949 have access to attributes for externs), then we know the result. */
11962 {
11963 /* We know that we're looking at the address of two
11964 non-weak, unaliased, static _DECL nodes.
11966 It is both wasteful and incorrect to call operand_equal_p
11967 to compare the two ADDR_EXPR nodes. It is wasteful in that
11968 all we need to do is test pointer equality for the arguments
11969 to the two ADDR_EXPR nodes. It is incorrect to use
11970 operand_equal_p as that function is NOT equivalent to a
11971 C equality test. It can in fact return false for two
11972 objects which would test as equal using the C equality
11973 operator. */
11977 type);
11978 }
11980 /* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
11981 a MINUS_EXPR of a constant, we can convert it into a comparison with
11982 a revised constant as long as no overflow occurs. */
11990 arg1),
11995 /* Similarly for a NEGATE_EXPR. */
12003 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
12011 arg1),
12014 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
12021 {
12025 val,
12029 }
12031 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
12036 {
12038 code == NE_EXPR
12041 }
12043 /* If we have X - Y == 0, we can convert that to X == Y and similarly
12044 for !=. Don't do this for ordered comparisons due to overflow. */
12050 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
12055 /* If this is an EQ or NE comparison with zero and ARG0 is
12056 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12057 two operations, but the latter can be done in one less insn
12058 on machines that have only two-operand insns or on which a
12059 constant cannot be the first operand. */
12062 {
12067 {
12074 arg1);
12075 }
12078 {
12085 arg1);
12086 }
12087 }
12089 /* If this is an NE or EQ comparison of zero against the result of a
12090 signed MOD operation whose second operand is a power of 2, make
12091 the MOD operation unsigned since it is simpler and equivalent. */
12099 {
12109 }
12111 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12112 C1 is a valid shift constant, and C2 is a power of two, i.e.
12113 a single bit. */
12117 == INTEGER_CST
12120 {
12125 /* Check for a valid shift count. */
12128 {
12132 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12133 can be rewritten as (X & (C2 << C1)) != 0. */
12135 {
12139 }
12140 /* Otherwise, for signed (arithmetic) shifts,
12141 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12142 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12146 /* Otherwise, of unsigned (logical) shifts,
12147 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12148 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12149 else
12153 arg000);
12154 }
12155 }
12157 /* If this is an NE comparison of zero with an AND of one, remove the
12158 comparison since the AND will give the correct value. */
12165 /* If we have (A & C) == C where C is a power of 2, convert this into
12166 (A & C) != 0. Similarly for NE_EXPR. */
12172 integer_zero_node));
12174 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12175 bit, then fold the expression into A < 0 or A >= 0. */
12180 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12181 Similarly for NE_EXPR. */
12185 {
12194 }
12196 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12197 Similarly for NE_EXPR. */
12201 {
12208 }
12210 /* If this is a comparison of a field, we may be able to simplify it. */
12213 /* Handle the constant case even without -O
12214 to make sure the warnings are given. */
12216 {
12220 }
12222 /* Optimize comparisons of strlen vs zero to a compare of the
12223 first character of the string vs zero. To wit,
12224 strlen(ptr) == 0 => *ptr == 0
12225 strlen(ptr) != 0 => *ptr != 0
12226 Other cases should reduce to one of these two (or a constant)
12227 due to the return value of strlen being unsigned. */
12230 {
12238 {
12243 }
12244 }
12246 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12247 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12251 {
12258 {
12260 {
12263 }
12266 }
12267 }
12269 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12275 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12280 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12287 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12295 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12296 (X & C) == 0 when C is a single bit. */
12301 {
12307 }
12309 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12310 constant C is a power of two, i.e. a single bit. */
12317 {
12321 }
12323 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12324 when is C is a power of two, i.e. a single bit. */
12331 {
12337 }
12341 {
12344 }
12346 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12353 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12356 {
12369 arg01),
12378 arg01),
12387 arg00),
12396 arg00),
12398 }
12402 {
12409 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12410 operand_equal_p guarantees no side-effects so we don't need
12411 to use omit_one_operand on Z. */
12421 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12429 arg10);
12430 }
12432 /* Attempt to simplify equality/inequality comparisons of complex
12433 values. Only lower the comparison if the result is known or
12434 can be simplified to a single scalar comparison. */
12439 {
12444 {
12447 }
12448 else
12449 {
12452 }
12455 {
12458 }
12459 else
12460 {
12463 }
12467 {
12469 {
12474 }
12475 else
12476 {
12481 }
12482 }
12486 {
12488 {
12493 }
12494 else
12495 {
12500 }
12501 }
12502 }
12514 /* Transform comparisons of the form X +- C CMP X. */
12521 {
12528 else
12531 /* (X - c) > X becomes false. */
12535 {
12539 "occur when assuming that (X - c) > X "
12541 WARN_STRICT_OVERFLOW_ALL);
12543 }
12545 /* Likewise (X + c) < X becomes false. */
12549 {
12553 "occur when assuming that "
12555 WARN_STRICT_OVERFLOW_ALL);
12557 }
12559 /* Convert (X - c) <= X to true. */
12564 {
12568 "occur when assuming that "
12570 WARN_STRICT_OVERFLOW_ALL);
12572 }
12574 /* Convert (X + c) >= X to true. */
12579 {
12583 "occur when assuming that "
12585 WARN_STRICT_OVERFLOW_ALL);
12587 }
12590 {
12591 /* Convert X + c > X and X - c < X to true for integers. */
12595 {
12598 "not occur when assuming that "
12600 WARN_STRICT_OVERFLOW_ALL);
12602 }
12607 {
12610 "not occur when assuming that "
12612 WARN_STRICT_OVERFLOW_ALL);
12614 }
12616 /* Convert X + c <= X and X - c >= X to false for integers. */
12620 {
12623 "not occur when assuming that "
12625 WARN_STRICT_OVERFLOW_ALL);
12627 }
12632 {
12635 "not occur when assuming that "
12637 WARN_STRICT_OVERFLOW_ALL);
12639 }
12640 }
12641 }
12643 /* Comparisons with the highest or lowest possible integer of
12644 the specified precision will have known values. */
12645 {
12652 {
12653 HOST_WIDE_INT signed_max_hi;
12658 {
12665 {
12669 }
12670 else
12671 {
12675 }
12676 }
12677 else
12678 {
12687 {
12690 }
12691 else
12692 {
12695 }
12696 }
12701 {
12714 /* The GE_EXPR and LT_EXPR cases above are not normally
12715 reached because of previous transformations. */
12719 }
12721 == max_hi
12724 {
12731 arg1);
12737 arg0),
12738 arg1);
12741 }
12743 == min_hi
12746 {
12761 }
12763 == min_hi
12766 {
12772 arg1);
12777 arg0),
12778 arg1);
12781 }
12786 /* We will flip the signedness of the comparison operator
12787 associated with the mode of arg1, so the sign bit is
12788 specified by this mode. Check that arg1 is the signed
12789 max associated with this sign bit. */
12791 /* signed_type does not work on pointer types. */
12793 {
12794 /* The following case also applies to X < signed_max+1
12795 and X >= signed_max+1 because previous transformations. */
12797 {
12798 tree st;
12804 }
12805 }
12806 }
12807 }
12809 /* If we are comparing an ABS_EXPR with a constant, we can
12810 convert all the cases into explicit comparisons, but they may
12811 well not be faster than doing the ABS and one comparison.
12812 But ABS (X) <= C is a range comparison, which becomes a subtraction
12813 and a comparison, and is probably faster. */
12827 /* Convert ABS_EXPR<x> >= 0 to true. */
12834 {
12837 "when simplifying comparison of "
12839 WARN_STRICT_OVERFLOW_CONDITIONAL);
12841 }
12843 /* Convert ABS_EXPR<x> < 0 to false. */
12848 {
12851 "when simplifying comparison of "
12853 WARN_STRICT_OVERFLOW_CONDITIONAL);
12855 }
12857 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12858 and similarly for >= into !=. */
12863 {
12869 }
12876 {
12885 }
12898 {
12902 }
12904 /* If the first operand is NaN, the result is constant. */
12908 {
12910 ? integer_zero_node
12913 }
12915 /* If the second operand is NaN, the result is constant. */
12919 {
12921 ? integer_zero_node
12924 }
12926 /* Simplify unordered comparison of something with itself. */
12932 && !flag_trapping_math
12936 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12937 {
12949 }
12954 /* When pedantic, a compound expression can be neither an lvalue
12955 nor an integer constant expression. */
12958 /* Don't let (0, 0) be null pointer constant. */
12972 /* An ASSERT_EXPR should never be passed to fold_binary. */
12978 fold_binary_exit:
12981 }
12983 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12984 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
12985 of GOTO_EXPR. */
12987 static tree
12989 {
12991 {
12998 /* ... fall through ... */
13002 }
13003 }
13005 /* Return whether the sub-tree ST contains a label which is accessible from
13006 outside the sub-tree. */
13008 static bool
13010 {
13011 return
13013 }
13015 /* Fold a ternary expression of code CODE and type TYPE with operands
13016 OP0, OP1, and OP2. Return the folded expression if folding is
13017 successful. Otherwise, return NULL_TREE. */
13019 tree
13022 {
13023 tree tem;
13030 /* Strip any conversions that don't change the mode. This is safe
13031 for every expression, except for a comparison expression because
13032 its signedness is derived from its operands. So, in the latter
13033 case, only strip conversions that don't change the signedness.
13035 Note that this is done as an internal manipulation within the
13036 constant folder, in order to find the simplest representation of
13037 the arguments so that their form can be studied. In any cases,
13038 the appropriate type conversions should be put back in the tree
13039 that will get out of the constant folder. */
13041 {
13044 }
13047 {
13050 }
13053 {
13057 {
13063 }
13067 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
13068 so all simple results must be passed through pedantic_non_lvalue. */
13070 {
13073 /* Only optimize constant conditions when the selected branch
13074 has the same type as the COND_EXPR. This avoids optimizing
13075 away "c ? x : throw", where the throw has a void type.
13076 Avoid throwing away that operand which contains label. */
13083 }
13087 /* If we have A op B ? A : C, we may be able to convert this to a
13088 simpler expression, depending on the operation and the values
13089 of B and C. Signed zeros prevent all of these transformations,
13090 for reasons given above each one.
13092 Also try swapping the arguments and inverting the conditional. */
13097 {
13101 }
13105 op2,
13108 {
13111 {
13115 }
13116 }
13118 /* If the second operand is simpler than the third, swap them
13119 since that produces better jump optimization results. */
13122 {
13123 /* See if this can be inverted. If it can't, possibly because
13124 it was a floating-point inequality comparison, don't do
13125 anything. */
13129 }
13131 /* Convert A ? 1 : 0 to simply A. */
13134 /* If we try to convert OP0 to our type, the
13135 call to fold will try to move the conversion inside
13136 a COND, which will recurse. In that case, the COND_EXPR
13137 is probably the best choice, so leave it alone. */
13141 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13142 over COND_EXPR in cases such as floating point comparisons. */
13149 arg0)));
13151 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13156 {
13157 /* sign_bit_p only checks ARG1 bits within A's precision.
13158 If <sign bit of A> has wider type than A, bits outside
13159 of A's precision in <sign bit of A> need to be checked.
13160 If they are all 0, this optimization needs to be done
13161 in unsigned A's type, if they are all 1 in signed A's type,
13162 otherwise this can't be done. */
13167 {
13169 HOST_WIDE_INT mask_hi;
13171 tree tem_type;
13179 {
13183 }
13184 else
13185 {
13189 }
13191 {
13195 }
13196 else
13202 {
13205 }
13208 {
13211 }
13212 else
13214 }
13217 return
13223 arg1)));
13224 }
13226 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13227 already handled above. */
13232 {
13241 }
13243 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13244 is probably obsolete because the first operand should be a
13245 truth value (that's why we have the two cases above), but let's
13246 leave it in until we can confirm this for all front-ends. */
13258 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13264 arg1);
13266 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13270 {
13271 /* Only perform transformation if ARG0 is easily inverted. */
13276 arg1);
13277 }
13279 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13283 {
13284 /* Only perform transformation if ARG0 is easily inverted. */
13289 op2);
13290 }
13292 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13298 op2);
13303 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13304 of fold_ternary on them. */
13311 {
13320 {
13325 else
13326 {
13328 tree value;
13332 }
13337 else
13339 }
13340 }
13342 /* A bit-field-ref that referenced the full argument can be stripped. */
13353 }
13355 /* Perform constant folding and related simplification of EXPR.
13356 The related simplifications include x*1 => x, x*0 => 0, etc.,
13357 and application of the associative law.
13358 NOP_EXPR conversions may be removed freely (as long as we
13359 are careful not to change the type of the overall expression).
13360 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13361 but we can constant-fold them if they have constant operands. */
13363 #ifdef ENABLE_FOLD_CHECKING
13364 # define fold(x) fold_1 (x)
13366 static
13367 #endif
13368 tree
13370 {
13374 tree tem;
13377 /* Return right away if a constant. */
13381 /* CALL_EXPR-like objects with variable numbers of operands are
13382 treated specially. */
13384 {
13386 {
13389 }
13391 }
13394 {
13399 {
13417 }
13418 }
13421 {
13423 {
13430 {
13435 /* Find a matching index by means of a binary search. */
13437 {
13453 else
13455 }
13456 }
13459 }
13467 }
13469 #ifdef ENABLE_FOLD_CHECKING
13470 #undef fold
13476 /* When --enable-checking=fold, compute a digest of expr before
13477 and after actual fold call to see if fold did not accidentally
13478 change original expr. */
13480 tree
13482 {
13483 tree ret;
13486 htab_t ht;
13505 }
13507 void
13509 {
13512 htab_t ht;
13522 }
13524 static void
13526 {
13528 }
13530 static void
13532 {
13538 recursive_label:
13552 {
13553 /* Allow DECL_ASSEMBLER_NAME to be modified. */
13557 }
13564 {
13565 /* Allow these fields to be modified. */
13566 tree tmp;
13574 {
13577 }
13578 }
13587 {
13590 {
13604 }
13608 {
13621 }
13638 {
13644 }
13649 {
13653 }
13664 {
13667 }
13677 }
13678 }
13680 /* Helper function for outputting the checksum of a tree T. When
13681 debugging with gdb, you can "define mynext" to be "next" followed
13682 by "call debug_fold_checksum (op0)", then just trace down till the
13683 outputs differ. */
13685 void
13687 {
13702 }
13704 #endif
13706 /* Fold a unary tree expression with code CODE of type TYPE with an
13707 operand OP0. LOC is the location of the resulting expression.
13708 Return a folded expression if successful. Otherwise, return a tree
13709 expression with code CODE of type TYPE with an operand OP0. */
13711 tree
13714 {
13715 tree tem;
13716 #ifdef ENABLE_FOLD_CHECKING
13719 htab_t ht;
13726 #endif
13730 {
13733 }
13735 #ifdef ENABLE_FOLD_CHECKING
13743 #endif
13745 }
13747 /* Fold a binary tree expression with code CODE of type TYPE with
13748 operands OP0 and OP1. LOC is the location of the resulting
13749 expression. Return a folded expression if successful. Otherwise,
13750 return a tree expression with code CODE of type TYPE with operands
13751 OP0 and OP1. */
13753 tree
13756 MEM_STAT_DECL)
13757 {
13758 tree tem;
13759 #ifdef ENABLE_FOLD_CHECKING
13765 htab_t ht;
13777 #endif
13781 {
13784 }
13786 #ifdef ENABLE_FOLD_CHECKING
13802 #endif
13804 }
13806 /* Fold a ternary tree expression with code CODE of type TYPE with
13807 operands OP0, OP1, and OP2. Return a folded expression if
13808 successful. Otherwise, return a tree expression with code CODE of
13809 type TYPE with operands OP0, OP1, and OP2. */
13811 tree
13814 {
13815 tree tem;
13816 #ifdef ENABLE_FOLD_CHECKING
13824 htab_t ht;
13841 #endif
13846 {
13849 }
13851 #ifdef ENABLE_FOLD_CHECKING
13875 #endif
13877 }
13879 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13880 arguments in ARGARRAY, and a null static chain.
13881 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13882 of type TYPE from the given operands as constructed by build_call_array. */
13884 tree
13887 {
13888 tree tem;
13889 #ifdef ENABLE_FOLD_CHECKING
13895 htab_t ht;
13909 #endif
13913 #ifdef ENABLE_FOLD_CHECKING
13930 #endif
13932 }
13934 /* Perform constant folding and related simplification of initializer
13935 expression EXPR. These behave identically to "fold_buildN" but ignore
13936 potential run-time traps and exceptions that fold must preserve. */
13938 #define START_FOLD_INIT \
13939 int saved_signaling_nans = flag_signaling_nans;\
13940 int saved_trapping_math = flag_trapping_math;\
13941 int saved_rounding_math = flag_rounding_math;\
13942 int saved_trapv = flag_trapv;\
13943 int saved_folding_initializer = folding_initializer;\
13944 flag_signaling_nans = 0;\
13945 flag_trapping_math = 0;\
13946 flag_rounding_math = 0;\
13947 flag_trapv = 0;\
13948 folding_initializer = 1;
13950 #define END_FOLD_INIT \
13951 flag_signaling_nans = saved_signaling_nans;\
13952 flag_trapping_math = saved_trapping_math;\
13953 flag_rounding_math = saved_rounding_math;\
13954 flag_trapv = saved_trapv;\
13955 folding_initializer = saved_folding_initializer;
13957 tree
13960 {
13961 tree result;
13962 START_FOLD_INIT;
13966 END_FOLD_INIT;
13968 }
13970 tree
13973 {
13974 tree result;
13975 START_FOLD_INIT;
13979 END_FOLD_INIT;
13981 }
13983 tree
13986 {
13987 tree result;
13988 START_FOLD_INIT;
13992 END_FOLD_INIT;
13994 }
13996 tree
13999 {
14000 tree result;
14001 START_FOLD_INIT;
14005 END_FOLD_INIT;
14007 }
14009 #undef START_FOLD_INIT
14010 #undef END_FOLD_INIT
14012 /* Determine if first argument is a multiple of second argument. Return 0 if
14013 it is not, or we cannot easily determined it to be.
14015 An example of the sort of thing we care about (at this point; this routine
14016 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14017 fold cases do now) is discovering that
14019 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14021 is a multiple of
14023 SAVE_EXPR (J * 8)
14025 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14027 This code also handles discovering that
14029 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14031 is a multiple of 8 so we don't have to worry about dealing with a
14032 possible remainder.
14034 Note that we *look* inside a SAVE_EXPR only to determine how it was
14035 calculated; it is not safe for fold to do much of anything else with the
14036 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14037 at run time. For example, the latter example above *cannot* be implemented
14038 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14039 evaluation time of the original SAVE_EXPR is not necessarily the same at
14040 the time the new expression is evaluated. The only optimization of this
14041 sort that would be valid is changing
14043 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14045 divided by 8 to
14047 SAVE_EXPR (I) * SAVE_EXPR (J)
14049 (where the same SAVE_EXPR (J) is used in the original and the
14050 transformed version). */
14052 int
14054 {
14062 {
14064 /* Bitwise and provides a power of two multiple. If the mask is
14065 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14068 /* FALLTHRU */
14081 {
14085 /* const_binop may not detect overflow correctly,
14086 so check for it explicitly here. */
14092 size_one_node,
14096 }
14100 /* Can't handle conversions from non-integral or wider integral type. */
14106 /* .. fall through ... */
14127 }
14128 }
14130 /* Return true if CODE or TYPE is known to be non-negative. */
14132 static bool
14134 {
14137 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14138 have a signed:1 type (where the value is -1 and 0). */
14141 }
14143 /* Return true if (CODE OP0) is known to be non-negative. If the return
14144 value is based on the assumption that signed overflow is undefined,
14145 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14146 *STRICT_OVERFLOW_P. */
14148 bool
14151 {
14156 {
14158 /* We can't return 1 if flag_wrapv is set because
14159 ABS_EXPR<INT_MIN> = INT_MIN. */
14163 {
14166 }
14173 strict_overflow_p);
14176 {
14181 {
14184 strict_overflow_p);
14186 {
14190 strict_overflow_p);
14191 }
14192 }
14194 {
14197 strict_overflow_p);
14201 }
14202 }
14207 }
14209 /* We don't know sign of `t', so be conservative and return false. */
14211 }
14213 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14214 value is based on the assumption that signed overflow is undefined,
14215 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14216 *STRICT_OVERFLOW_P. */
14218 bool
14221 {
14226 {
14231 strict_overflow_p)
14233 strict_overflow_p));
14235 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14236 both unsigned and at least 2 bits shorter than the result. */
14240 {
14245 {
14249 }
14250 }
14255 {
14256 /* x * x for floating point x is always non-negative. */
14260 strict_overflow_p)
14262 strict_overflow_p));
14263 }
14265 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14266 both unsigned and their total bits is shorter than the result. */
14270 {
14289 {
14299 }
14300 }
14306 strict_overflow_p)
14308 strict_overflow_p));
14319 strict_overflow_p)
14321 strict_overflow_p));
14328 strict_overflow_p);
14331 }
14333 /* We don't know sign of `t', so be conservative and return false. */
14335 }
14337 /* Return true if T is known to be non-negative. If the return
14338 value is based on the assumption that signed overflow is undefined,
14339 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14340 *STRICT_OVERFLOW_P. */
14342 bool
14344 {
14349 {
14361 strict_overflow_p)
14363 strict_overflow_p));
14367 }
14368 /* We don't know sign of `t', so be conservative and return false. */
14370 }
14372 /* Return true if T is known to be non-negative. If the return
14373 value is based on the assumption that signed overflow is undefined,
14374 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14375 *STRICT_OVERFLOW_P. */
14377 bool
14380 {
14383 {
14401 /* Always true. */
14405 /* sqrt(-0.0) is -0.0. */
14409 strict_overflow_p);
14442 /* True if the 1st argument is nonnegative. */
14444 strict_overflow_p);
14447 /* True if the 1st OR 2nd arguments are nonnegative. */
14449 strict_overflow_p)
14451 strict_overflow_p)));
14454 /* True if the 1st AND 2nd arguments are nonnegative. */
14456 strict_overflow_p)
14458 strict_overflow_p)));
14461 /* True if the 2nd argument is nonnegative. */
14463 strict_overflow_p);
14466 /* True if the 1st argument is nonnegative or the second
14467 argument is an even integer. */
14472 strict_overflow_p);
14475 /* True if the 1st argument is nonnegative or the second
14476 argument is an even integer valued real. */
14478 {
14479 REAL_VALUE_TYPE c;
14480 HOST_WIDE_INT n;
14485 {
14486 REAL_VALUE_TYPE cint;
14491 }
14492 }
14494 strict_overflow_p);
14498 }
14500 type);
14501 }
14503 /* Return true if T is known to be non-negative. If the return
14504 value is based on the assumption that signed overflow is undefined,
14505 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14506 *STRICT_OVERFLOW_P. */
14508 bool
14510 {
14516 {
14518 {
14522 /* If the initializer is non-void, then it's a normal expression
14523 that will be assigned to the slot. */
14527 /* Otherwise, the initializer sets the slot in some way. One common
14528 way is an assignment statement at the end of the initializer. */
14530 {
14538 else
14540 }
14544 strict_overflow_p);
14547 }
14550 {
14556 arg0,
14557 arg1,
14558 strict_overflow_p);
14559 }
14563 strict_overflow_p);
14566 strict_overflow_p);
14569 strict_overflow_p);
14574 }
14576 /* We don't know sign of `t', so be conservative and return false. */
14578 }
14580 /* Return true if T is known to be non-negative. If the return
14581 value is based on the assumption that signed overflow is undefined,
14582 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14583 *STRICT_OVERFLOW_P. */
14585 bool
14587 {
14594 {
14601 strict_overflow_p);
14607 strict_overflow_p);
14616 }
14619 {
14627 strict_overflow_p);
14632 strict_overflow_p);
14645 }
14646 }
14648 /* Return true if `t' is known to be non-negative. Handle warnings
14649 about undefined signed overflow. */
14651 bool
14653 {
14660 "determining that expression is always "
14662 WARN_STRICT_OVERFLOW_MISC);
14664 }
14667 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14668 For floating point we further ensure that T is not denormal.
14669 Similar logic is present in nonzero_address in rtlanal.h.
14671 If the return value is based on the assumption that signed overflow
14672 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14673 change *STRICT_OVERFLOW_P. */
14675 bool
14678 {
14680 {
14683 strict_overflow_p);
14686 {
14692 strict_overflow_p));
14693 }
14698 strict_overflow_p);
14702 }
14705 }
14707 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14708 For floating point we further ensure that T is not denormal.
14709 Similar logic is present in nonzero_address in rtlanal.h.
14711 If the return value is based on the assumption that signed overflow
14712 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14713 change *STRICT_OVERFLOW_P. */
14715 bool
14717 tree type,
14718 tree op0,
14720 {
14723 {
14727 {
14728 /* With the presence of negative values it is hard
14729 to say something. */
14736 /* One of operands must be positive and the other non-negative. */
14737 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14738 overflows, on a twos-complement machine the sum of two
14739 nonnegative numbers can never be zero. */
14741 strict_overflow_p)
14743 strict_overflow_p));
14744 }
14749 {
14751 strict_overflow_p)
14753 strict_overflow_p))
14754 {
14757 }
14758 }
14767 {
14770 }
14777 {
14781 /* When both operands are nonzero, then MAX must be too. */
14783 strict_overflow_p))
14786 /* MAX where operand 0 is positive is positive. */
14788 strict_overflow_p);
14789 }
14790 /* MAX where operand 1 is positive is positive. */
14795 {
14799 }
14804 strict_overflow_p)
14806 strict_overflow_p));
14810 }
14813 }
14815 /* Return true when T is an address and is known to be nonzero.
14816 For floating point we further ensure that T is not denormal.
14817 Similar logic is present in nonzero_address in rtlanal.h.
14819 If the return value is based on the assumption that signed overflow
14820 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14821 change *STRICT_OVERFLOW_P. */
14823 bool
14825 {
14828 {
14833 {
14839 /* Weak declarations may link to NULL. Other things may also be NULL
14840 so protect with -fdelete-null-pointer-checks; but not variables
14841 allocated on the stack. */
14843 && (flag_delete_null_pointer_checks
14847 /* Constants are never weak. */
14852 }
14860 {
14864 }
14869 }
14871 }
14873 /* Return true when T is an address and is known to be nonzero.
14874 For floating point we further ensure that T is not denormal.
14875 Similar logic is present in nonzero_address in rtlanal.h.
14877 If the return value is based on the assumption that signed overflow
14878 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14879 change *STRICT_OVERFLOW_P. */
14881 bool
14883 {
14887 /* Doing something useful for floating point would need more work. */
14893 {
14896 strict_overflow_p);
14902 strict_overflow_p);
14910 }
14913 {
14916 strict_overflow_p);
14924 strict_overflow_p);
14939 strict_overflow_p);
14943 strict_overflow_p);
14950 }
14952 }
14954 /* Return true when T is an address and is known to be nonzero.
14955 Handle warnings about undefined signed overflow. */
14957 bool
14959 {
14966 "determining that expression is always "
14968 WARN_STRICT_OVERFLOW_MISC);
14970 }
14972 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14973 attempt to fold the expression to a constant without modifying TYPE,
14974 OP0 or OP1.
14976 If the expression could be simplified to a constant, then return
14977 the constant. If the expression would not be simplified to a
14978 constant, then return NULL_TREE. */
14980 tree
14982 {
14985 }
14987 /* Given the components of a unary expression CODE, TYPE and OP0,
14988 attempt to fold the expression to a constant without modifying
14989 TYPE or OP0.
14991 If the expression could be simplified to a constant, then return
14992 the constant. If the expression would not be simplified to a
14993 constant, then return NULL_TREE. */
14995 tree
14997 {
15000 }
15002 /* If EXP represents referencing an element in a constant string
15003 (either via pointer arithmetic or array indexing), return the
15004 tree representing the value accessed, otherwise return NULL. */
15006 tree
15008 {
15012 {
15014 tree index;
15015 tree string;
15020 else
15021 {
15025 /* Optimize the special-case of a zero lower bound.
15027 We convert the low_bound to sizetype to avoid some problems
15028 with constant folding. (E.g. suppose the lower bound is 1,
15029 and its mode is QI. Without the conversion,l (ARRAY
15030 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15031 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15037 }
15050 }
15052 }
15054 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15055 an integer constant, real, or fixed-point constant.
15057 TYPE is the type of the result. */
15059 static tree
15061 {
15065 {
15067 {
15069 HOST_WIDE_INT high;
15077 }
15084 {
15085 FIXED_VALUE_TYPE f;
15090 /* Propagate overflow flags. */
15094 }
15098 }
15101 }
15103 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15104 an integer constant or real constant.
15106 TYPE is the type of the result. */
15108 tree
15110 {
15114 {
15116 /* If the value is unsigned, then the absolute value is
15117 the same as the ordinary value. */
15120 /* Similarly, if the value is non-negative. */
15123 /* If the value is negative, then the absolute value is
15124 its negation. */
15125 else
15126 {
15128 HOST_WIDE_INT high;
15134 }
15140 else
15146 }
15149 }
15151 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15152 constant. TYPE is the type of the result. */
15154 static tree
15156 {
15166 }
15168 /* Given CODE, a relational operator, the target type, TYPE and two
15169 constant operands OP0 and OP1, return the result of the
15170 relational operation. If the result is not a compile time
15171 constant, then return NULL_TREE. */
15173 static tree
15175 {
15178 /* From here on, the only cases we handle are when the result is
15179 known to be a constant. */
15182 {
15186 /* Handle the cases where either operand is a NaN. */
15188 {
15190 {
15218 }
15221 }
15224 }
15227 {
15231 }
15233 /* Handle equality/inequality of complex constants. */
15235 {
15246 else
15248 }
15250 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15252 To compute GT, swap the arguments and do LT.
15253 To compute GE, do LT and invert the result.
15254 To compute LE, swap the arguments, do LT and invert the result.
15255 To compute NE, do EQ and invert the result.
15257 Therefore, the code below must handle only EQ and LT. */
15260 {
15265 }
15267 /* Note that it is safe to invert for real values here because we
15268 have already handled the one case that it matters. */
15272 {
15275 }
15277 /* Compute a result for LT or EQ if args permit;
15278 Otherwise return T. */
15280 {
15285 else
15287 }
15288 else
15294 }
15296 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15297 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15298 itself. */
15300 tree
15302 {
15303 /* If the expression does not have side effects then we don't have to wrap
15304 it with a cleanup point expression. */
15308 /* If the expression is a return, check to see if the expression inside the
15309 return has no side effects or the right hand side of the modify expression
15310 inside the return. If either don't have side effects set we don't need to
15311 wrap the expression in a cleanup point expression. Note we don't check the
15312 left hand side of the modify because it should always be a return decl. */
15314 {
15321 }
15324 }
15326 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15327 of an indirection through OP0, or NULL_TREE if no simplification is
15328 possible. */
15330 tree
15332 {
15334 tree subtype;
15342 {
15345 /* *&CONST_DECL -> to the value of the const decl. */
15348 /* *&p => p; make sure to handle *&"str"[cst] here. */
15350 {
15354 else
15356 }
15357 /* *(foo *)&fooarray => fooarray[0] */
15360 {
15368 }
15369 /* *(foo *)&complexfoo => __real__ complexfoo */
15373 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15376 {
15380 }
15381 }
15383 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15386 {
15389 tree op00type;
15396 {
15408 }
15409 }
15412 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15415 {
15418 tree op00type;
15425 {
15430 }
15431 }
15433 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15436 {
15437 tree type_domain;
15446 }
15449 }
15451 /* Builds an expression for an indirection through T, simplifying some
15452 cases. */
15454 tree
15456 {
15466 }
15468 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15470 tree
15472 {
15477 else
15479 }
15481 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15482 whose result is ignored. The type of the returned tree need not be
15483 the same as the original expression. */
15485 tree
15487 {
15493 {
15504 else
15510 {
15526 }
15531 }
15532 }
15534 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
15535 This can only be applied to objects of a sizetype. */
15537 tree
15539 {
15546 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15547 have to do anything. Only do this when we are not given a const,
15548 because in that case, this check is more expensive than just
15549 doing it. */
15551 {
15556 }
15558 /* If divisor is a power of two, simplify this to bit manipulation. */
15560 {
15562 {
15575 {
15576 high++;
15579 }
15583 }
15584 else
15585 {
15586 tree t;
15592 }
15593 }
15594 else
15595 {
15600 }
15603 }
15605 /* Likewise, but round down. */
15607 tree
15609 {
15616 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15617 have to do anything. Only do this when we are not given a const,
15618 because in that case, this check is more expensive than just
15619 doing it. */
15621 {
15626 }
15628 /* If divisor is a power of two, simplify this to bit manipulation. */
15630 {
15631 tree t;
15635 }
15636 else
15637 {
15642 }
15645 }
15647 /* Returns the pointer to the base of the object addressed by EXP and
15648 extracts the information about the offset of the access, storing it
15649 to PBITPOS and POFFSET. */
15651 static tree
15654 {
15655 tree core;
15658 HOST_WIDE_INT bitsize;
15662 {
15667 }
15668 else
15669 {
15673 }
15676 }
15678 /* Returns true if addresses of E1 and E2 differ by a constant, false
15679 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15681 bool
15683 {
15697 {
15707 }
15709 {
15710 /* If only one of the offsets is non-constant, the difference cannot
15711 be a constant. */
15713 }
15714 else
15719 }
15721 /* Simplify the floating point expression EXP when the sign of the
15722 result is not significant. Return NULL_TREE if no simplification
15723 is possible. */
15725 tree
15727 {
15732 {
15768 {
15771 {
15773 /* Strip copysign function call, return the 1st argument. */
15779 /* Strip sign ops from the argument of "odd" math functions. */
15781 {
15785 }
15787 }
15788 }
15793 }
15795 }