| blob | f6fb8af8084d875b108754bba37febb1342bedea |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
87 /* Nonzero if we are folding constants inside an initializer; zero
88 otherwise. */
91 /* The following constants represent a bit based encoding of GCC's
92 comparison operators. This encoding simplifies transformations
93 on relational comparison operators, such as AND and OR. */
111 };
130 HOST_WIDE_INT *,
160 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
161 Otherwise, return LOC. */
163 static location_t
165 {
168 }
170 /* Similar to protected_set_expr_location, but never modify x in place,
171 if location can and needs to be set, unshare it. */
175 {
181 {
184 }
186 }
187 \f
188 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
189 division and returns the quotient. Otherwise returns
190 NULL_TREE. */
192 tree
194 {
195 widest_int quo;
202 }
203 \f
204 /* This is nonzero if we should defer warnings about undefined
205 overflow. This facility exists because these warnings are a
206 special case. The code to estimate loop iterations does not want
207 to issue any warnings, since it works with expressions which do not
208 occur in user code. Various bits of cleanup code call fold(), but
209 only use the result if it has certain characteristics (e.g., is a
210 constant); that code only wants to issue a warning if the result is
211 used. */
215 /* If a warning about undefined overflow is deferred, this is the
216 warning. Note that this may cause us to turn two warnings into
217 one, but that is fine since it is sufficient to only give one
218 warning per expression. */
222 /* If a warning about undefined overflow is deferred, this is the
223 level at which the warning should be emitted. */
227 /* Start deferring overflow warnings. We could use a stack here to
228 permit nested calls, but at present it is not necessary. */
230 void
232 {
234 }
236 /* Stop deferring overflow warnings. If there is a pending warning,
237 and ISSUE is true, then issue the warning if appropriate. STMT is
238 the statement with which the warning should be associated (used for
239 location information); STMT may be NULL. CODE is the level of the
240 warning--a warn_strict_overflow_code value. This function will use
241 the smaller of CODE and the deferred code when deciding whether to
242 issue the warning. CODE may be zero to mean to always use the
243 deferred code. */
245 void
247 {
249 location_t locus;
254 {
260 }
271 /* Use the smallest code level when deciding to issue the
272 warning. */
281 else
284 }
286 /* Stop deferring overflow warnings, ignoring any deferred
287 warnings. */
289 void
291 {
293 }
295 /* Whether we are deferring overflow warnings. */
297 bool
299 {
301 }
303 /* This is called when we fold something based on the fact that signed
304 overflow is undefined. */
306 static void
308 {
310 {
313 {
316 }
317 }
320 }
321 \f
322 /* Return true if the built-in mathematical function specified by CODE
323 is odd, i.e. -f(x) == f(-x). */
325 static bool
327 {
329 {
363 }
365 }
367 /* Check whether we may negate an integer constant T without causing
368 overflow. */
370 bool
372 {
373 tree type;
382 }
384 /* Determine whether an expression T can be cheaply negated using
385 the function negate_expr without introducing undefined overflow. */
387 static bool
389 {
390 tree type;
399 {
404 /* Check that -CST will not overflow type. */
415 /* We want to canonicalize to positive real constants. Pretend
416 that only negative ones can be easily negated. */
424 {
435 }
448 /* -(A + B) -> (-B) - A. */
453 /* -(A + B) -> (-A) - B. */
457 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
467 /* Fall through. */
478 /* In general we can't negate A / B, because if A is INT_MIN and
479 B is 1, we may turn this into INT_MIN / -1 which is undefined
480 and actually traps on some architectures. But if overflow is
481 undefined, we can negate, because - (INT_MIN / 1) is an
482 overflow. */
484 {
487 /* If overflow is undefined then we have to be careful because
488 we ask whether it's ok to associate the negate with the
489 division which is not ok for example for
490 -((a - b) / c) where (-(a - b)) / c may invoke undefined
491 overflow because of negating INT_MIN. So do not use
492 negate_expr_p here but open-code the two important cases. */
497 }
503 /* Negate -((double)float) as (double)(-float). */
505 {
509 }
513 /* Negate -f(x) as f(-x). */
519 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
521 {
525 }
530 }
532 }
534 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
535 simplification is possible.
536 If negate_expr_p would return true for T, NULL_TREE will never be
537 returned. */
539 static tree
541 {
543 tree tem;
546 {
547 /* Convert - (~A) to A + 1. */
564 /* Two's complement FP formats, such as c4x, may overflow. */
574 {
583 }
587 {
592 {
596 }
599 }
622 {
623 /* -(A + B) -> (-B) - A. */
627 {
631 }
633 /* -(A + B) -> (-A) - B. */
635 {
639 }
640 }
644 /* - (A - B) -> B - A */
656 /* Fall through. */
660 {
669 }
675 /* In general we can't negate A / B, because if A is INT_MIN and
676 B is 1, we may turn this into INT_MIN / -1 which is undefined
677 and actually traps on some architectures. But if overflow is
678 undefined, we can negate, because - (INT_MIN / 1) is an
679 overflow. */
681 {
686 {
693 }
694 /* If overflow is undefined then we have to be careful because
695 we ask whether it's ok to associate the negate with the
696 division which is not ok for example for
697 -((a - b) / c) where (-(a - b)) / c may invoke undefined
698 overflow because of negating INT_MIN. So do not use
699 negate_expr_p here but open-code the two important cases. */
708 }
712 /* Convert -((double)float) into (double)(-float). */
714 {
718 }
722 /* Negate -f(x) as f(-x). */
725 {
731 }
735 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
737 {
740 {
747 }
748 }
753 }
756 }
758 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
759 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
760 return NULL_TREE. */
762 static tree
764 {
766 location_t loc;
779 }
780 \f
781 /* Split a tree IN into a constant, literal and variable parts that could be
782 combined with CODE to make IN. "constant" means an expression with
783 TREE_CONSTANT but that isn't an actual constant. CODE must be a
784 commutative arithmetic operation. Store the constant part into *CONP,
785 the literal in *LITP and return the variable part. If a part isn't
786 present, set it to null. If the tree does not decompose in this way,
787 return the entire tree as the variable part and the other parts as null.
789 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
790 case, we negate an operand that was subtracted. Except if it is a
791 literal for which we use *MINUS_LITP instead.
793 If NEGATE_P is true, we are negating all of IN, again except a literal
794 for which we use *MINUS_LITP instead.
796 If IN is itself a literal or constant, return it as appropriate.
798 Note that we do not guarantee that any of the three values will be the
799 same type as IN, but they will have the same signedness and mode. */
801 static tree
804 {
811 /* Strip any conversions that don't change the machine mode or signedness. */
820 /* We can associate addition and subtraction together (even
821 though the C standard doesn't say so) for integers because
822 the value is not affected. For reals, the value might be
823 affected, so we can't. */
826 {
832 /* First see if either of the operands is a literal, then a constant. */
845 /* If we haven't dealt with either operand, this is not a case we can
846 decompose. Otherwise, VAR is either of the ones remaining, if any. */
851 else
854 /* Now do any needed negations. */
861 }
864 {
865 /* -X - 1 is folded to ~X, undo that here. */
868 }
871 else
875 {
882 }
885 }
887 /* Re-associate trees split by the above function. T1 and T2 are
888 either expressions to associate or null. Return the new
889 expression, if any. LOC is the location of the new expression. If
890 we build an operation, do it in TYPE and with CODE. */
892 static tree
894 {
900 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
901 try to fold this since we will have infinite recursion. But do
902 deal with any NEGATE_EXPRs. */
905 {
907 {
920 }
922 {
925 }
929 }
933 }
934 \f
935 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
936 for use in int_const_binop, size_binop and size_diffop. */
938 static bool
940 {
947 {
956 }
961 }
964 /* Combine two integer constants ARG1 and ARG2 under operation CODE
965 to produce a new constant. Return NULL_TREE if we don't know how
966 to evaluate CODE at compile-time. */
968 static tree
971 {
972 wide_int res;
973 tree t;
982 {
998 {
1002 else
1004 }
1007 /* It's unclear from the C standard whether shifts can overflow.
1008 The following code ignores overflow; perhaps a C standard
1009 interpretation ruling is needed. */
1011 else
1018 {
1022 else
1024 }
1028 else
1107 }
1115 }
1117 tree
1119 {
1121 }
1123 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1124 constant. We assume ARG1 and ARG2 have the same data type, or at least
1125 are the same kind of constant and the same machine mode. Return zero if
1126 combining the constants is not allowed in the current operating mode. */
1128 static tree
1130 {
1131 /* Sanity check for the recursive cases. */
1142 {
1143 machine_mode mode;
1144 REAL_VALUE_TYPE d1;
1145 REAL_VALUE_TYPE d2;
1146 REAL_VALUE_TYPE value;
1147 REAL_VALUE_TYPE result;
1151 /* The following codes are handled by real_arithmetic. */
1153 {
1164 }
1172 /* Don't perform operation if we honor signaling NaNs and
1173 either operand is a NaN. */
1178 /* Don't perform operation if it would raise a division
1179 by zero exception. */
1185 /* If either operand is a NaN, just return it. Otherwise, set up
1186 for floating-point trap; we return an overflow. */
1195 /* Don't constant fold this floating point operation if
1196 the result has overflowed and flag_trapping_math. */
1204 /* Don't constant fold this floating point operation if the
1205 result may dependent upon the run-time rounding mode and
1206 flag_rounding_math is set, or if GCC's software emulation
1207 is unable to accurately represent the result. */
1217 }
1220 {
1221 FIXED_VALUE_TYPE f1;
1222 FIXED_VALUE_TYPE f2;
1223 FIXED_VALUE_TYPE result;
1228 /* The following codes are handled by fixed_arithmetic. */
1230 {
1240 {
1245 }
1250 }
1257 /* Propagate overflow flags. */
1261 }
1264 {
1273 {
1284 mpc_mul);
1298 mpc_div);
1299 /* Fallthru ... */
1305 {
1306 /* Keep this algorithm in sync with
1307 tree-complex.c:expand_complex_div_straight().
1309 Expand complex division to scalars, straightforward algorithm.
1310 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1311 t = br*br + bi*bi
1312 */
1313 tree magsquared
1317 tree t1
1321 tree t2
1328 }
1329 else
1330 {
1331 /* Keep this algorithm in sync with
1332 tree-complex.c:expand_complex_div_wide().
1334 Expand complex division to scalars, modified algorithm to minimize
1335 overflow with wide input ranges. */
1341 {
1342 /* In the TRUE branch, we compute
1343 ratio = br/bi;
1344 div = (br * ratio) + bi;
1345 tr = (ar * ratio) + ai;
1346 ti = (ai * ratio) - ar;
1347 tr = tr / div;
1348 ti = ti / div; */
1359 }
1360 else
1361 {
1362 /* In the FALSE branch, we compute
1363 ratio = d/c;
1364 divisor = (d * ratio) + c;
1365 tr = (b * ratio) + a;
1366 ti = b - (a * ratio);
1367 tr = tr / div;
1368 ti = ti / div; */
1380 }
1381 }
1386 }
1390 }
1394 {
1400 {
1406 /* It is possible that const_binop cannot handle the given
1407 code and return NULL_TREE */
1410 }
1413 }
1415 /* Shifts allow a scalar offset for a vector. */
1418 {
1424 {
1429 /* It is possible that const_binop cannot handle the given
1430 code and return NULL_TREE. */
1433 }
1436 }
1438 }
1440 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1441 indicates which particular sizetype to create. */
1443 tree
1445 {
1447 }
1448 \f
1449 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1450 is a tree code. The type of the result is taken from the operands.
1451 Both must be equivalent integer types, ala int_binop_types_match_p.
1452 If the operands are constant, so is the result. */
1454 tree
1456 {
1465 /* Handle the special case of two integer constants faster. */
1467 {
1468 /* And some specific cases even faster than that. */
1470 {
1475 }
1477 {
1480 }
1482 {
1485 }
1487 /* Handle general case of two integer constants. For sizetype
1488 constant calculations we always want to know about overflow,
1489 even in the unsigned case. */
1491 }
1494 }
1496 /* Given two values, either both of sizetype or both of bitsizetype,
1497 compute the difference between the two values. Return the value
1498 in signed type corresponding to the type of the operands. */
1500 tree
1502 {
1504 tree ctype;
1509 /* If the type is already signed, just do the simple thing. */
1517 else
1520 /* If either operand is not a constant, do the conversions to the signed
1521 type and subtract. The hardware will do the right thing with any
1522 overflow in the subtraction. */
1528 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1529 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1530 overflow) and negate (which can't either). Special-case a result
1531 of zero while we're here. */
1537 else
1541 MINUS_EXPR,
1543 }
1544 \f
1545 /* A subroutine of fold_convert_const handling conversions of an
1546 INTEGER_CST to another integer type. */
1548 static tree
1550 {
1551 /* Given an integer constant, make new constant with new type,
1552 appropriately sign-extended or truncated. Use widest_int
1553 so that any extension is done according ARG1's type. */
1557 }
1559 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1560 to an integer type. */
1562 static tree
1564 {
1566 tree t;
1568 /* The following code implements the floating point to integer
1569 conversion rules required by the Java Language Specification,
1570 that IEEE NaNs are mapped to zero and values that overflow
1571 the target precision saturate, i.e. values greater than
1572 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1573 are mapped to INT_MIN. These semantics are allowed by the
1574 C and C++ standards that simply state that the behavior of
1575 FP-to-integer conversion is unspecified upon overflow. */
1577 wide_int val;
1578 REAL_VALUE_TYPE r;
1582 {
1589 }
1591 /* If R is NaN, return zero and show we have an overflow. */
1593 {
1596 }
1598 /* See if R is less than the lower bound or greater than the
1599 upper bound. */
1602 {
1606 {
1609 }
1610 }
1613 {
1616 {
1619 {
1622 }
1623 }
1624 }
1631 }
1633 /* A subroutine of fold_convert_const handling conversions of a
1634 FIXED_CST to an integer type. */
1636 static tree
1638 {
1639 tree t;
1643 /* Right shift FIXED_CST to temp by fbit. */
1647 {
1649 HOST_BITS_PER_DOUBLE_INT,
1652 /* Left shift temp to temp_trunc by fbit. */
1654 HOST_BITS_PER_DOUBLE_INT,
1656 }
1657 else
1658 {
1661 }
1663 /* If FIXED_CST is negative, we need to round the value toward 0.
1664 By checking if the fractional bits are not zero to add 1 to temp. */
1670 /* Given a fixed-point constant, make new constant with new type,
1671 appropriately sign-extended or truncated. */
1679 }
1681 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1682 to another floating point type. */
1684 static tree
1686 {
1687 REAL_VALUE_TYPE value;
1688 tree t;
1693 /* If converting an infinity or NAN to a representation that doesn't
1694 have one, set the overflow bit so that we can produce some kind of
1695 error message at the appropriate point if necessary. It's not the
1696 most user-friendly message, but it's better than nothing. */
1703 /* Regular overflow, conversion produced an infinity in a mode that
1704 can't represent them. */
1709 else
1712 }
1714 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1715 to a floating point type. */
1717 static tree
1719 {
1720 REAL_VALUE_TYPE value;
1721 tree t;
1728 }
1730 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1731 to another fixed-point type. */
1733 static tree
1735 {
1736 FIXED_VALUE_TYPE value;
1737 tree t;
1744 /* Propagate overflow flags. */
1748 }
1750 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
1751 to a fixed-point type. */
1753 static tree
1755 {
1756 FIXED_VALUE_TYPE value;
1757 tree t;
1759 double_int di;
1766 else
1774 /* Propagate overflow flags. */
1778 }
1780 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1781 to a fixed-point type. */
1783 static tree
1785 {
1786 FIXED_VALUE_TYPE value;
1787 tree t;
1795 /* Propagate overflow flags. */
1799 }
1801 /* Attempt to fold type conversion operation CODE of expression ARG1 to
1802 type TYPE. If no simplification can be done return NULL_TREE. */
1804 static tree
1806 {
1812 {
1819 }
1821 {
1828 }
1830 {
1837 }
1839 }
1841 /* Construct a vector of zero elements of vector type TYPE. */
1843 static tree
1845 {
1846 tree t;
1850 }
1852 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
1854 bool
1856 {
1871 {
1890 }
1891 }
1893 /* Convert expression ARG to type TYPE. Used by the middle-end for
1894 simple conversions in preference to calling the front-end's convert. */
1896 tree
1898 {
1900 tree tem;
1911 {
1914 /* Handle conversions between pointers to different address spaces. */
1919 /* fall through */
1924 {
1928 }
1942 {
1946 }
1948 {
1952 }
1954 {
1958 }
1961 {
1979 }
1984 {
1988 }
1991 {
2005 }
2009 {
2018 integer_zero_node));
2020 {
2024 {
2030 }
2038 }
2042 }
2060 }
2061 fold_convert_exit:
2064 }
2065 \f
2066 /* Return false if expr can be assumed not to be an lvalue, true
2067 otherwise. */
2069 static bool
2071 {
2072 /* We only need to wrap lvalue tree codes. */
2074 {
2105 /* Assume the worst for front-end tree codes. */
2109 }
2112 }
2114 /* Return an expr equal to X but certainly not valid as an lvalue. */
2116 tree
2118 {
2119 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2120 us. */
2127 }
2129 /* When pedantic, return an expr equal to X but certainly not valid as a
2130 pedantic lvalue. Otherwise, return X. */
2132 static tree
2134 {
2136 }
2137 \f
2138 /* Given a tree comparison code, return the code that is the logical inverse.
2139 It is generally not safe to do this for floating-point comparisons, except
2140 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2141 ERROR_MARK in this case. */
2143 enum tree_code
2145 {
2151 {
2182 }
2183 }
2185 /* Similar, but return the comparison that results if the operands are
2186 swapped. This is safe for floating-point. */
2188 enum tree_code
2190 {
2192 {
2218 }
2219 }
2222 /* Convert a comparison tree code from an enum tree_code representation
2223 into a compcode bit-based encoding. This function is the inverse of
2224 compcode_to_comparison. */
2226 static enum comparison_code
2228 {
2230 {
2261 }
2262 }
2264 /* Convert a compcode bit-based encoding of a comparison operator back
2265 to GCC's enum tree_code representation. This function is the
2266 inverse of comparison_to_compcode. */
2268 static enum tree_code
2270 {
2272 {
2303 }
2304 }
2306 /* Return a tree for the comparison which is the combination of
2307 doing the AND or OR (depending on CODE) of the two operations LCODE
2308 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2309 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2310 if this makes the transformation invalid. */
2312 tree
2317 {
2324 {
2335 }
2338 {
2339 /* Eliminate unordered comparisons, as well as LTGT and ORD
2340 which are not used unless the mode has NaNs. */
2346 }
2348 {
2349 /* Check that the original operation and the optimized ones will trap
2350 under the same condition. */
2361 /* In a short-circuited boolean expression the LHS might be
2362 such that the RHS, if evaluated, will never trap. For
2363 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2364 if neither x nor y is NaN. (This is a mixed blessing: for
2365 example, the expression above will never trap, hence
2366 optimizing it to x < y would be invalid). */
2371 /* If the comparison was short-circuited, and only the RHS
2372 trapped, we may now generate a spurious trap. */
2377 /* If we changed the conditions that cause a trap, we lose. */
2380 }
2386 else
2387 {
2392 }
2393 }
2394 \f
2395 /* Return nonzero if two operands (typically of the same tree node)
2396 are necessarily equal. If either argument has side-effects this
2397 function returns zero. FLAGS modifies behavior as follows:
2399 If OEP_ONLY_CONST is set, only return nonzero for constants.
2400 This function tests whether the operands are indistinguishable;
2401 it does not test whether they are equal using C's == operation.
2402 The distinction is important for IEEE floating point, because
2403 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2404 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2406 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2407 even though it may hold multiple values during a function.
2408 This is because a GCC tree node guarantees that nothing else is
2409 executed between the evaluation of its "operands" (which may often
2410 be evaluated in arbitrary order). Hence if the operands themselves
2411 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2412 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2413 unset means assuming isochronic (or instantaneous) tree equivalence.
2414 Unless comparing arbitrary expression trees, such as from different
2415 statements, this flag can usually be left unset.
2417 If OEP_PURE_SAME is set, then pure functions with identical arguments
2418 are considered the same. It is used when the caller has other ways
2419 to ensure that global memory is unchanged in between. */
2421 int
2423 {
2424 /* If either is ERROR_MARK, they aren't equal. */
2430 /* Similar, if either does not have a type (like a released SSA name),
2431 they aren't equal. */
2435 /* Check equality of integer constants before bailing out due to
2436 precision differences. */
2440 /* If both types don't have the same signedness, then we can't consider
2441 them equal. We must check this before the STRIP_NOPS calls
2442 because they may change the signedness of the arguments. As pointers
2443 strictly don't have a signedness, require either two pointers or
2444 two non-pointers as well. */
2449 /* We cannot consider pointers to different address space equal. */
2455 /* If both types don't have the same precision, then it is not safe
2456 to strip NOPs. */
2464 /* In case both args are comparisons but with different comparison
2465 code, try to swap the comparison operands of one arg to produce
2466 a match and compare that variant. */
2470 {
2478 }
2481 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2485 /* This is needed for conversions and for COMPONENT_REF.
2486 Might as well play it safe and always test this. */
2492 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2493 We don't care about side effects in that case because the SAVE_EXPR
2494 takes care of that for us. In all other cases, two expressions are
2495 equal if they have no side effects. If we have two identical
2496 expressions with side effects that should be treated the same due
2497 to the only side effects being identical SAVE_EXPR's, that will
2498 be detected in the recursive calls below.
2499 If we are taking an invariant address of two identical objects
2500 they are necessarily equal as well. */
2507 /* Next handle constant cases, those for which we can return 1 even
2508 if ONLY_CONST is set. */
2511 {
2526 {
2527 /* If we do not distinguish between signed and unsigned zero,
2528 consider them equal. */
2531 }
2535 {
2542 {
2546 }
2548 }
2552 flags)
2554 flags));
2568 }
2573 /* Define macros to test an operand from arg0 and arg1 for equality and a
2574 variant that allows null and views null as being different from any
2575 non-null value. In the latter case, if either is null, the both
2576 must be; otherwise, do the normal comparison. */
2577 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2578 TREE_OPERAND (arg1, N), flags)
2580 #define OP_SAME_WITH_NULL(N) \
2581 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2582 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2585 {
2587 /* Two conversions are equal only if signedness and modes match. */
2589 {
2590 CASE_CONVERT:
2598 }
2608 /* For commutative ops, allow the other order. */
2616 /* If either of the pointer (or reference) expressions we are
2617 dereferencing contain a side effect, these cannot be equal,
2618 but their addresses can be. */
2625 {
2636 /* Require equal extra operands and then fall through to MEM_REF
2637 handling of the two common operands. */
2642 /* Fallthru. */
2645 /* Require equal access sizes, and similar pointer types.
2646 We can have incomplete types for array references of
2647 variable-sized arrays from the Fortran frontend
2648 though. Also verify the types are compatible. */
2655 && alias_ptr_types_compatible_p
2662 /* Operands 2 and 3 may be null.
2663 Compare the array index by value if it is constant first as we
2664 may have different types but same value here. */
2675 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
2676 may be NULL when we're called to compare MEM_EXPRs. */
2691 }
2695 {
2709 /* The multiplcation operands are commutative. */
2710 /* FALLTHRU */
2718 /* Otherwise take into account this is a commutative operation. */
2731 }
2735 {
2737 /* If the CALL_EXPRs call different functions, then they
2738 clearly can not be equal. */
2740 flags))
2743 {
2747 else
2751 }
2753 /* Now see if all the arguments are the same. */
2754 {
2765 /* If we get here and both argument lists are exhausted
2766 then the CALL_EXPRs are equal. */
2768 }
2771 }
2774 /* Consider __builtin_sqrt equal to sqrt. */
2782 }
2784 #undef OP_SAME
2785 #undef OP_SAME_WITH_NULL
2786 }
2787 \f
2788 /* Similar to operand_equal_p, but see if ARG0 might have been made by
2789 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
2791 When in doubt, return 0. */
2793 static int
2795 {
2807 /* Discard any conversions that don't change the modes of ARG0 and ARG1
2808 and see if the inner values are the same. This removes any
2809 signedness comparison, which doesn't matter here. */
2816 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
2817 actual comparison operand, ARG0.
2819 First throw away any conversions to wider types
2820 already present in the operands. */
2829 {
2832 /* Make sure shorter operand is extended the right way
2833 to match the longer operand. */
2839 }
2842 }
2843 \f
2844 /* See if ARG is an expression that is either a comparison or is performing
2845 arithmetic on comparisons. The comparisons must only be comparing
2846 two different values, which will be stored in *CVAL1 and *CVAL2; if
2847 they are nonzero it means that some operands have already been found.
2848 No variables may be used anywhere else in the expression except in the
2849 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2850 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2852 If this is true, return 1. Otherwise, return zero. */
2854 static int
2856 {
2860 /* We can handle some of the tcc_expression cases here. */
2870 {
2871 /* If we've already found a CVAL1 or CVAL2, this expression is
2872 two complex to handle. */
2878 }
2881 {
2904 /* First see if we can handle the first operand, then the second. For
2905 the second operand, we know *CVAL1 can't be zero. It must be that
2906 one side of the comparison is each of the values; test for the
2907 case where this isn't true by failing if the two operands
2908 are the same. */
2917 ;
2921 ;
2922 else
2926 ;
2930 ;
2931 else
2938 }
2939 }
2940 \f
2941 /* ARG is a tree that is known to contain just arithmetic operations and
2942 comparisons. Evaluate the operations in the tree substituting NEW0 for
2943 any occurrence of OLD0 as an operand of a comparison and likewise for
2944 NEW1 and OLD1. */
2946 static tree
2949 {
2954 /* We can handle some of the tcc_expression cases here. */
2962 {
2977 {
2996 }
2997 /* Fall through - ??? */
3000 {
3004 /* We need to check both for exact equality and tree equality. The
3005 former will be true if the operand has a side-effect. In that
3006 case, we know the operand occurred exactly once. */
3019 }
3023 }
3024 }
3025 \f
3026 /* Return a tree for the case when the result of an expression is RESULT
3027 converted to TYPE and OMITTED was previously an operand of the expression
3028 but is now not needed (e.g., we folded OMITTED * 0).
3030 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3031 the conversion of RESULT to TYPE. */
3033 tree
3035 {
3038 /* If the resulting operand is an empty statement, just return the omitted
3039 statement casted to void. */
3049 }
3051 /* Return a tree for the case when the result of an expression is RESULT
3052 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3053 of the expression but are now not needed.
3055 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3056 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3057 evaluated before OMITTED2. Otherwise, if neither has side effects,
3058 just do the conversion of RESULT to TYPE. */
3060 tree
3063 {
3072 }
3074 \f
3075 /* Return a simplified tree node for the truth-negation of ARG. This
3076 never alters ARG itself. We assume that ARG is an operation that
3077 returns a truth value (0 or 1).
3079 FIXME: one would think we would fold the result, but it causes
3080 problems with the dominator optimizer. */
3082 static tree
3084 {
3089 /* If this is a comparison, we can simply invert it, except for
3090 floating-point non-equality comparisons, in which case we just
3091 enclose a TRUTH_NOT_EXPR around what we have. */
3094 {
3097 && flag_trapping_math
3108 }
3111 {
3130 /* Here we can invert either operand. We invert the first operand
3131 unless the second operand is a TRUTH_NOT_EXPR in which case our
3132 result is the XOR of the first operand with the inside of the
3133 negation of the second operand. */
3138 else
3161 {
3168 /* A COND_EXPR may have a throw as one operand, which
3169 then has void type. Just leave void operands
3170 as they are. */
3176 }
3188 CASE_CONVERT:
3192 /* ... fall through ... */
3214 }
3215 }
3217 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3218 assume that ARG is an operation that returns a truth value (0 or 1
3219 for scalars, 0 or -1 for vectors). Return the folded expression if
3220 folding is successful. Otherwise, return NULL_TREE. */
3222 static tree
3224 {
3227 ? BIT_NOT_EXPR
3230 }
3232 /* Return a simplified tree node for the truth-negation of ARG. This
3233 never alters ARG itself. We assume that ARG is an operation that
3234 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3236 tree
3238 {
3244 ? BIT_NOT_EXPR
3247 }
3249 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3250 operands are another bit-wise operation with a common input. If so,
3251 distribute the bit operations to save an operation and possibly two if
3252 constants are involved. For example, convert
3253 (A | B) & (A | C) into A | (B & C)
3254 Further simplification will occur if B and C are constants.
3256 If this optimization cannot be done, 0 will be returned. */
3258 static tree
3261 {
3262 tree common;
3272 {
3276 }
3278 {
3282 }
3284 {
3288 }
3290 {
3294 }
3295 else
3303 }
3305 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3306 with code CODE. This optimization is unsafe. */
3307 static tree
3310 {
3314 /* (A / C) +- (B / C) -> (A +- B) / C. */
3324 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3329 {
3341 }
3344 }
3345 \f
3346 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3347 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3349 static tree
3352 {
3356 {
3363 }
3377 }
3379 /* Optimize a bit-field compare.
3381 There are two cases: First is a compare against a constant and the
3382 second is a comparison of two items where the fields are at the same
3383 bit position relative to the start of a chunk (byte, halfword, word)
3384 large enough to contain it. In these cases we can avoid the shift
3385 implicit in bitfield extractions.
3387 For constants, we emit a compare of the shifted constant with the
3388 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3389 compared. For two fields at the same position, we do the ANDs with the
3390 similar mask and compare the result of the ANDs.
3392 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3393 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3394 are the left and right operands of the comparison, respectively.
3396 If the optimization described above can be done, we return the resulting
3397 tree. Otherwise we return zero. */
3399 static tree
3402 {
3405 tree unsigned_type;
3411 tree mask;
3412 tree offset;
3414 /* Get all the information about the extractions being done. If the bit size
3415 if the same as the size of the underlying object, we aren't doing an
3416 extraction at all and so can do nothing. We also don't want to
3417 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3418 then will no longer be able to replace it. */
3426 {
3427 /* If this is not a constant, we can only do something if bit positions,
3428 sizes, and signedness are the same. */
3436 }
3438 /* See if we can find a mode to refer to this field. We should be able to,
3439 but fail if we can't. */
3448 /* Set signed and unsigned types of the precision of this mode for the
3449 shifts below. */
3452 /* Compute the bit position and size for the new reference and our offset
3453 within it. If the new reference is the same size as the original, we
3454 won't optimize anything, so return zero. */
3464 /* Make the mask to be used against the extracted field. */
3471 /* If not comparing with constant, just rework the comparison
3472 and return. */
3476 unsigned_type,
3479 mask),
3482 unsigned_type,
3485 mask));
3487 /* Otherwise, we are handling the constant case. See if the constant is too
3488 big for the field. Warn and return a tree of for 0 (false) if so. We do
3489 this not only for its own sake, but to avoid having to test for this
3490 error case below. If we didn't, we might generate wrong code.
3492 For unsigned fields, the constant shifted right by the field length should
3493 be all zero. For signed fields, the high-order bits should agree with
3494 the sign bit. */
3497 {
3499 {
3503 }
3504 }
3505 else
3506 {
3509 {
3513 }
3514 }
3516 /* Single-bit compares should always be against zero. */
3518 {
3521 }
3523 /* Make a new bitfield reference, shift the constant over the
3524 appropriate number of bits and mask it with the computed mask
3525 (in case this was a signed field). If we changed it, make a new one. */
3532 mask);
3537 }
3538 \f
3539 /* Subroutine for fold_truth_andor_1: decode a field reference.
3541 If EXP is a comparison reference, we return the innermost reference.
3543 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3544 set to the starting bit number.
3546 If the innermost field can be completely contained in a mode-sized
3547 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3549 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3550 otherwise it is not changed.
3552 *PUNSIGNEDP is set to the signedness of the field.
3554 *PMASK is set to the mask used. This is either contained in a
3555 BIT_AND_EXPR or derived from the width of the field.
3557 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3559 Return 0 if this is not a component reference or is one that we can't
3560 do anything with. */
3562 static tree
3567 {
3571 tree unsigned_type;
3574 /* All the optimizations using this function assume integer fields.
3575 There are problems with FP fields since the type_for_size call
3576 below can fail for, e.g., XFmode. */
3580 /* We are interested in the bare arrangement of bits, so strip everything
3581 that doesn't affect the machine mode. However, record the type of the
3582 outermost expression if it may matter below. */
3589 {
3595 }
3604 /* If the number of bits in the reference is the same as the bitsize of
3605 the outer type, then the outer type gives the signedness. Otherwise
3606 (in case of a small bitfield) the signedness is unchanged. */
3610 /* Compute the mask to access the bitfield. */
3619 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3627 }
3629 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
3630 bit positions and MASK is SIGNED. */
3632 static int
3634 {
3638 /* If this function returns true when the type of the mask is
3639 UNSIGNED, then there will be errors. In particular see
3640 gcc.c-torture/execute/990326-1.c. There does not appear to be
3641 any documentation paper trail as to why this is so. But the pre
3642 wide-int worked with that restriction and it has been preserved
3643 here. */
3648 }
3650 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3651 represents the sign bit of EXP's type. If EXP represents a sign
3652 or zero extension, also test VAL against the unextended type.
3653 The return value is the (sub)expression whose sign bit is VAL,
3654 or NULL_TREE otherwise. */
3656 tree
3658 {
3660 tree t;
3662 /* Tree EXP must have an integral type. */
3667 /* Tree VAL must be an integer constant. */
3676 /* Handle extension from a narrower type. */
3682 }
3684 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
3685 to be evaluated unconditionally. */
3687 static int
3689 {
3690 /* Strip any conversions that don't change the machine mode. */
3699 /* Don't regard global variables as simple. They may be
3700 allocated in ways unknown to the compiler (shared memory,
3701 #pragma weak, etc). */
3704 /* Weakrefs are not safe to be read, since they can be NULL.
3705 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
3706 have DECL_WEAK flag set. */
3708 /* Loading a static variable is unduly expensive, but global
3709 registers aren't expensive. */
3711 }
3713 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
3714 to be evaluated unconditionally.
3715 I addition to simple_operand_p, we assume that comparisons, conversions,
3716 and logic-not operations are simple, if their operands are simple, too. */
3718 static bool
3720 {
3740 }
3742 \f
3743 /* The following functions are subroutines to fold_range_test and allow it to
3744 try to change a logical combination of comparisons into a range test.
3746 For example, both
3747 X == 2 || X == 3 || X == 4 || X == 5
3748 and
3749 X >= 2 && X <= 5
3750 are converted to
3751 (unsigned) (X - 2) <= 3
3753 We describe each set of comparisons as being either inside or outside
3754 a range, using a variable named like IN_P, and then describe the
3755 range with a lower and upper bound. If one of the bounds is omitted,
3756 it represents either the highest or lowest value of the type.
3758 In the comments below, we represent a range by two numbers in brackets
3759 preceded by a "+" to designate being inside that range, or a "-" to
3760 designate being outside that range, so the condition can be inverted by
3761 flipping the prefix. An omitted bound is represented by a "-". For
3762 example, "- [-, 10]" means being outside the range starting at the lowest
3763 possible value and ending at 10, in other words, being greater than 10.
3764 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
3765 always false.
3767 We set up things so that the missing bounds are handled in a consistent
3768 manner so neither a missing bound nor "true" and "false" need to be
3769 handled using a special case. */
3771 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
3772 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
3773 and UPPER1_P are nonzero if the respective argument is an upper bound
3774 and zero for a lower. TYPE, if nonzero, is the type of the result; it
3775 must be specified for a comparison. ARG1 will be converted to ARG0's
3776 type if both are specified. */
3778 static tree
3781 {
3782 tree tem;
3786 /* If neither arg represents infinity, do the normal operation.
3787 Else, if not a comparison, return infinity. Else handle the special
3788 comparison rules. Note that most of the cases below won't occur, but
3789 are handled for consistency. */
3792 {
3797 }
3802 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
3803 for neither. In real maths, we cannot assume open ended ranges are
3804 the same. But, this is computer arithmetic, where numbers are finite.
3805 We can therefore make the transformation of any unbounded range with
3806 the value Z, Z being greater than any representable number. This permits
3807 us to treat unbounded ranges as equal. */
3811 {
3832 }
3835 }
3836 \f
3837 /* Helper routine for make_range. Perform one step for it, return
3838 new expression if the loop should continue or NULL_TREE if it should
3839 stop. */
3841 tree
3845 {
3851 {
3853 /* We can only do something if the range is testing for zero. */
3862 /* We can only do something if the range is testing for zero
3863 and if the second operand is an integer constant. Note that
3864 saying something is "in" the range we make is done by
3865 complementing IN_P since it will set in the initial case of
3866 being not equal to zero; "out" is leaving it alone. */
3873 {
3894 }
3896 /* If this is an unsigned comparison, we also know that EXP is
3897 greater than or equal to zero. We base the range tests we make
3898 on that fact, so we record it here so we can parse existing
3899 range tests. We test arg0_type since often the return type
3900 of, e.g. EQ_EXPR, is boolean. */
3902 {
3906 NULL_TREE))
3911 /* If the high bound is missing, but we have a nonzero low
3912 bound, reverse the range so it goes from zero to the low bound
3913 minus 1. */
3915 {
3920 }
3921 }
3929 /* If flag_wrapv and ARG0_TYPE is signed, make sure
3930 low and high are non-NULL, then normalize will DTRT. */
3933 {
3938 }
3940 /* (-x) IN [a,b] -> x in [-b, -a] */
3952 /* ~ X -> -X - 1 */
3961 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
3962 move a constant to the other side. */
3967 /* If EXP is signed, any overflow in the computation is undefined,
3968 so we don't worry about it so long as our computations on
3969 the bounds don't overflow. For unsigned, overflow is defined
3970 and this is exactly the right thing. */
3982 normalize:
3983 /* Check for an unsigned range which has wrapped around the maximum
3984 value thus making n_high < n_low, and normalize it. */
3986 {
3992 /* If the range is of the form +/- [ x+1, x ], we won't
3993 be able to normalize it. But then, it represents the
3994 whole range or the empty set, so make it
3995 +/- [ -, - ]. */
3999 else
4001 }
4002 else
4010 CASE_CONVERT:
4028 /* If we're converting arg0 from an unsigned type, to exp,
4029 a signed type, we will be doing the comparison as unsigned.
4030 The tests above have already verified that LOW and HIGH
4031 are both positive.
4033 So we have to ensure that we will handle large unsigned
4034 values the same way that the current signed bounds treat
4035 negative values. */
4038 {
4039 tree high_positive;
4040 tree equiv_type;
4041 /* For fixed-point modes, we need to pass the saturating flag
4042 as the 2nd parameter. */
4044 equiv_type
4047 else
4048 equiv_type
4051 /* A range without an upper bound is, naturally, unbounded.
4052 Since convert would have cropped a very large value, use
4053 the max value for the destination type. */
4054 high_positive
4061 high_positive),
4064 /* If the low bound is specified, "and" the range with the
4065 range for which the original unsigned value will be
4066 positive. */
4068 {
4071 integer_zero_node),
4072 high_positive))
4076 }
4077 else
4078 {
4079 /* Otherwise, "or" the range with the range of the input
4080 that will be interpreted as negative. */
4083 integer_zero_node),
4084 high_positive))
4088 }
4089 }
4098 }
4099 }
4101 /* Given EXP, a logical expression, set the range it is testing into
4102 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4103 actually being tested. *PLOW and *PHIGH will be made of the same
4104 type as the returned expression. If EXP is not a comparison, we
4105 will most likely not be returning a useful value and range. Set
4106 *STRICT_OVERFLOW_P to true if the return value is only valid
4107 because signed overflow is undefined; otherwise, do not change
4108 *STRICT_OVERFLOW_P. */
4110 tree
4113 {
4121 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4122 and see if we can refine the range. Some of the cases below may not
4123 happen, but it doesn't seem worth worrying about this. We "continue"
4124 the outer loop when we've changed something; otherwise we "break"
4125 the switch, which will "break" the while. */
4131 {
4137 {
4145 }
4154 }
4156 /* If EXP is a constant, we can evaluate whether this is true or false. */
4158 {
4165 }
4169 }
4170 \f
4171 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4172 type, TYPE, return an expression to test if EXP is in (or out of, depending
4173 on IN_P) the range. Return 0 if the test couldn't be created. */
4175 tree
4178 {
4181 #ifdef HAVE_canonicalize_funcptr_for_compare
4182 /* Disable this optimization for function pointer expressions
4183 on targets that require function pointer canonicalization. */
4188 #endif
4191 {
4197 }
4215 {
4217 {
4221 }
4223 }
4225 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4227 {
4231 {
4233 {
4236 etype
4238 else
4241 }
4244 }
4245 }
4247 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4248 This requires wrap-around arithmetics for the type of the expression.
4249 First make sure that arithmetics in this type is valid, then make sure
4250 that it wraps around. */
4256 {
4259 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4260 for the type in question, as we rely on this here. */
4270 else
4272 }
4282 {
4284 {
4289 }
4291 }
4299 }
4300 \f
4301 /* Return the predecessor of VAL in its type, handling the infinite case. */
4303 static tree
4305 {
4311 else
4314 }
4316 /* Return the successor of VAL in its type, handling the infinite case. */
4318 static tree
4320 {
4326 else
4329 }
4331 /* Given two ranges, see if we can merge them into one. Return 1 if we
4332 can, 0 if we can't. Set the output range into the specified parameters. */
4334 bool
4337 {
4341 tree tem;
4351 /* Make range 0 be the range that starts first, or ends last if they
4352 start at the same value. Swap them if it isn't. */
4355 || (lowequal
4358 {
4362 }
4364 /* Now flag two cases, whether the ranges are disjoint or whether the
4365 second range is totally subsumed in the first. Note that the tests
4366 below are simplified by the ones above. */
4372 /* We now have four cases, depending on whether we are including or
4373 excluding the two ranges. */
4375 {
4376 /* If they don't overlap, the result is false. If the second range
4377 is a subset it is the result. Otherwise, the range is from the start
4378 of the second to the end of the first. */
4383 else
4385 }
4388 {
4389 /* If they don't overlap, the result is the first range. If they are
4390 equal, the result is false. If the second range is a subset of the
4391 first, and the ranges begin at the same place, we go from just after
4392 the end of the second range to the end of the first. If the second
4393 range is not a subset of the first, or if it is a subset and both
4394 ranges end at the same place, the range starts at the start of the
4395 first range and ends just before the second range.
4396 Otherwise, we can't describe this as a single range. */
4402 {
4407 {
4408 /* We are in the weird situation where high0 > high1 but
4409 high1 has no successor. Punt. */
4411 }
4412 }
4414 {
4419 {
4420 /* low0 < low1 but low1 has no predecessor. Punt. */
4422 }
4423 }
4424 else
4426 }
4429 {
4430 /* If they don't overlap, the result is the second range. If the second
4431 is a subset of the first, the result is false. Otherwise,
4432 the range starts just after the first range and ends at the
4433 end of the second. */
4438 else
4439 {
4444 {
4445 /* high1 > high0 but high0 has no successor. Punt. */
4447 }
4448 }
4449 }
4451 else
4452 {
4453 /* The case where we are excluding both ranges. Here the complex case
4454 is if they don't overlap. In that case, the only time we have a
4455 range is if they are adjacent. If the second is a subset of the
4456 first, the result is the first. Otherwise, the range to exclude
4457 starts at the beginning of the first range and ends at the end of the
4458 second. */
4460 {
4465 else
4466 {
4467 /* Canonicalize - [min, x] into - [-, x]. */
4470 {
4475 /* FALLTHROUGH */
4488 }
4490 /* Canonicalize - [x, max] into - [x, -]. */
4493 {
4498 /* FALLTHROUGH */
4514 }
4516 /* The ranges might be also adjacent between the maximum and
4517 minimum values of the given type. For
4518 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4519 return + [x + 1, y - 1]. */
4521 {
4528 }
4529 else
4531 }
4532 }
4535 else
4537 }
4541 }
4542 \f
4544 /* Subroutine of fold, looking inside expressions of the form
4545 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4546 of the COND_EXPR. This function is being used also to optimize
4547 A op B ? C : A, by reversing the comparison first.
4549 Return a folded expression whose code is not a COND_EXPR
4550 anymore, or NULL_TREE if no folding opportunity is found. */
4552 static tree
4555 {
4560 tree tem;
4565 /* If we have A op 0 ? A : -A, consider applying the following
4566 transformations:
4568 A == 0? A : -A same as -A
4569 A != 0? A : -A same as A
4570 A >= 0? A : -A same as abs (A)
4571 A > 0? A : -A same as abs (A)
4572 A <= 0? A : -A same as -abs (A)
4573 A < 0? A : -A same as -abs (A)
4575 None of these transformations work for modes with signed
4576 zeros. If A is +/-0, the first two transformations will
4577 change the sign of the result (from +0 to -0, or vice
4578 versa). The last four will fix the sign of the result,
4579 even though the original expressions could be positive or
4580 negative, depending on the sign of A.
4582 Note that all these transformations are correct if A is
4583 NaN, since the two alternatives (A and -A) are also NaNs. */
4590 /* In the case that A is of the form X-Y, '-A' (arg2) may
4591 have already been folded to Y-X, check for that. */
4599 {
4613 /* Fall through. */
4635 }
4637 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4638 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4639 both transformations are correct when A is NaN: A != 0
4640 is then true, and A == 0 is false. */
4644 {
4649 }
4651 /* Try some transformations of A op B ? A : B.
4653 A == B? A : B same as B
4654 A != B? A : B same as A
4655 A >= B? A : B same as max (A, B)
4656 A > B? A : B same as max (B, A)
4657 A <= B? A : B same as min (A, B)
4658 A < B? A : B same as min (B, A)
4660 As above, these transformations don't work in the presence
4661 of signed zeros. For example, if A and B are zeros of
4662 opposite sign, the first two transformations will change
4663 the sign of the result. In the last four, the original
4664 expressions give different results for (A=+0, B=-0) and
4665 (A=-0, B=+0), but the transformed expressions do not.
4667 The first two transformations are correct if either A or B
4668 is a NaN. In the first transformation, the condition will
4669 be false, and B will indeed be chosen. In the case of the
4670 second transformation, the condition A != B will be true,
4671 and A will be chosen.
4673 The conversions to max() and min() are not correct if B is
4674 a number and A is not. The conditions in the original
4675 expressions will be false, so all four give B. The min()
4676 and max() versions would give a NaN instead. */
4679 /* Avoid these transformations if the COND_EXPR may be used
4680 as an lvalue in the C++ front-end. PR c++/19199. */
4681 && (in_gimple_form
4687 {
4692 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4694 {
4698 }
4701 {
4710 /* In C++ a ?: expression can be an lvalue, so put the
4711 operand which will be used if they are equal first
4712 so that we can convert this back to the
4713 corresponding COND_EXPR. */
4715 {
4724 }
4731 {
4740 }
4755 }
4756 }
4758 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
4759 we might still be able to simplify this. For example,
4760 if C1 is one less or one more than C2, this might have started
4761 out as a MIN or MAX and been transformed by this function.
4762 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
4768 {
4772 /* We can replace A with C1 in this case. */
4777 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
4778 MIN_EXPR, to preserve the signedness of the comparison. */
4780 OEP_ONLY_CONST)
4784 OEP_ONLY_CONST))
4785 {
4788 arg2));
4791 }
4795 /* If C1 is C2 - 1, this is min(A, C2), with the same care
4796 as above. */
4798 OEP_ONLY_CONST)
4802 OEP_ONLY_CONST))
4803 {
4806 arg2));
4809 }
4813 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
4814 MAX_EXPR, to preserve the signedness of the comparison. */
4816 OEP_ONLY_CONST)
4820 OEP_ONLY_CONST))
4821 {
4824 arg2));
4826 }
4830 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
4832 OEP_ONLY_CONST)
4836 OEP_ONLY_CONST))
4837 {
4840 arg2));
4842 }
4848 }
4851 }
4854 \f
4855 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
4856 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
4857 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
4858 false) >= 2)
4859 #endif
4861 /* EXP is some logical combination of boolean tests. See if we can
4862 merge it into some range test. Return the new tree if so. */
4864 static tree
4867 {
4883 /* If this is an OR operation, invert both sides; we will invert
4884 again at the end. */
4888 /* If both expressions are the same, if we can merge the ranges, and we
4889 can build the range test, return it or it inverted. If one of the
4890 ranges is always true or always false, consider it to be the same
4891 expression as the other. */
4899 {
4903 }
4905 /* On machines where the branch cost is expensive, if this is a
4906 short-circuited branch and the underlying object on both sides
4907 is the same, make a non-short-circuit operation. */
4913 {
4914 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
4915 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
4916 which cases we can't do this. */
4924 {
4933 {
4936 WARN_STRICT_OVERFLOW_COMPARISON);
4940 }
4941 }
4942 }
4945 }
4946 \f
4947 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
4948 bit value. Arrange things so the extra bits will be set to zero if and
4949 only if C is signed-extended to its full width. If MASK is nonzero,
4950 it is an INTEGER_CST that should be AND'ed with the extra bits. */
4952 static tree
4954 {
4957 tree temp;
4962 /* We work by getting just the sign bit into the low-order bit, then
4963 into the high-order bit, then sign-extend. We then XOR that value
4964 with C. */
4967 /* We must use a signed type in order to get an arithmetic right shift.
4968 However, we must also avoid introducing accidental overflows, so that
4969 a subsequent call to integer_zerop will work. Hence we must
4970 do the type conversion here. At this point, the constant is either
4971 zero or one, and the conversion to a signed type can never overflow.
4972 We could get an overflow if this conversion is done anywhere else. */
4981 /* If necessary, convert the type back to match the type of C. */
4986 }
4987 \f
4988 /* For an expression that has the form
4989 (A && B) || ~B
4990 or
4991 (A || B) && ~B,
4992 we can drop one of the inner expressions and simplify to
4993 A || ~B
4994 or
4995 A && ~B
4996 LOC is the location of the resulting expression. OP is the inner
4997 logical operation; the left-hand side in the examples above, while CMPOP
4998 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
4999 removing a condition that guards another, as in
5000 (A != NULL && A->...) || A == NULL
5001 which we must not transform. If RHS_ONLY is true, only eliminate the
5002 right-most operand of the inner logical operation. */
5004 static tree
5007 {
5025 {
5028 {
5031 }
5032 }
5034 {
5037 {
5040 }
5041 }
5056 }
5058 /* Find ways of folding logical expressions of LHS and RHS:
5059 Try to merge two comparisons to the same innermost item.
5060 Look for range tests like "ch >= '0' && ch <= '9'".
5061 Look for combinations of simple terms on machines with expensive branches
5062 and evaluate the RHS unconditionally.
5064 For example, if we have p->a == 2 && p->b == 4 and we can make an
5065 object large enough to span both A and B, we can do this with a comparison
5066 against the object ANDed with the a mask.
5068 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5069 operations to do this with one comparison.
5071 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5072 function and the one above.
5074 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5075 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5077 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5078 two operands.
5080 We return the simplified tree or 0 if no optimization is possible. */
5082 static tree
5085 {
5086 /* If this is the "or" of two comparisons, we can do something if
5087 the comparisons are NE_EXPR. If this is the "and", we can do something
5088 if the comparisons are EQ_EXPR. I.e.,
5089 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5091 WANTED_CODE is this operation code. For single bit fields, we can
5092 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5093 comparison for one-bit fields. */
5113 /* Start by getting the comparison codes. Fail if anything is volatile.
5114 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5115 it were surrounded with a NE_EXPR. */
5124 {
5128 }
5131 {
5135 }
5146 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5149 {
5152 {
5157 }
5160 {
5166 }
5167 }
5172 /* If the RHS can be evaluated unconditionally and its operands are
5173 simple, it wins to evaluate the RHS unconditionally on machines
5174 with expensive branches. In this case, this isn't a comparison
5175 that can be merged. */
5182 {
5183 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5194 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5204 }
5206 /* See if the comparisons can be merged. Then get all the parameters for
5207 each side. */
5231 /* It must be true that the inner operation on the lhs of each
5232 comparison must be the same if we are to be able to do anything.
5233 Then see if we have constants. If not, the same must be true for
5234 the rhs's. */
5245 else
5248 /* If either comparison code is not correct for our logical operation,
5249 fail. However, we can convert a one-bit comparison against zero into
5250 the opposite comparison against that bit being set in the field. */
5254 {
5256 {
5257 /* Make the left operand unsigned, since we are only interested
5258 in the value of one bit. Otherwise we are doing the wrong
5259 thing below. */
5262 }
5263 else
5265 }
5267 /* This is analogous to the code for l_const above. */
5269 {
5271 {
5274 }
5275 else
5277 }
5279 /* See if we can find a mode that contains both fields being compared on
5280 the left. If we can't, fail. Otherwise, update all constants and masks
5281 to be relative to a field of that size. */
5286 volatilep);
5296 {
5299 }
5307 {
5314 {
5318 }
5319 }
5321 {
5328 {
5332 }
5333 }
5335 /* If the right sides are not constant, do the same for it. Also,
5336 disallow this optimization if a size or signedness mismatch occurs
5337 between the left and right sides. */
5339 {
5342 /* Make sure the two fields on the right
5343 correspond to the left without being swapped. */
5351 volatilep);
5361 {
5364 }
5373 /* Make a mask that corresponds to both fields being compared.
5374 Do this for both items being compared. If the operands are the
5375 same size and the bits being compared are in the same position
5376 then we can do this by masking both and comparing the masked
5377 results. */
5381 {
5393 }
5395 /* There is still another way we can do something: If both pairs of
5396 fields being compared are adjacent, we may be able to make a wider
5397 field containing them both.
5399 Note that we still must mask the lhs/rhs expressions. Furthermore,
5400 the mask must be shifted to account for the shift done by
5401 make_bit_field_ref. */
5406 {
5407 tree type;
5421 /* Convert to the smaller type before masking out unwanted bits. */
5424 {
5426 {
5430 }
5432 {
5436 }
5437 }
5446 }
5449 }
5451 /* Handle the case of comparisons with constants. If there is something in
5452 common between the masks, those bits of the constants must be the same.
5453 If not, the condition is always false. Test for this to avoid generating
5454 incorrect code below. */
5459 {
5461 {
5464 }
5465 else
5466 {
5469 }
5470 }
5472 /* Construct the expression we will return. First get the component
5473 reference we will make. Unless the mask is all ones the width of
5474 that field, perform the mask operation. Then compare with the
5475 merged constant. */
5485 }
5486 \f
5487 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5488 constant. */
5490 static tree
5493 {
5496 tree comp_const;
5497 tree minmax_const;
5499 tree inner;
5510 /* If something does not permit us to optimize, return the original tree. */
5518 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5519 and GT_EXPR, doing the rest with recursive calls using logical
5520 simplifications. */
5522 {
5524 {
5525 tree tem
5532 }
5535 return
5537 optimize_minmax_comparison
5539 optimize_minmax_comparison
5544 /* MAX (X, 0) == 0 -> X <= 0 */
5548 /* MAX (X, 0) == 5 -> X == 5 */
5552 /* MAX (X, 0) == -1 -> false */
5556 /* MIN (X, 0) == 0 -> X >= 0 */
5560 /* MIN (X, 0) == 5 -> false */
5563 else
5564 /* MIN (X, 0) == -1 -> X == -1 */
5569 /* MAX (X, 0) > 0 -> X > 0
5570 MAX (X, 0) > 5 -> X > 5 */
5574 /* MAX (X, 0) > -1 -> true */
5578 /* MIN (X, 0) > 0 -> false
5579 MIN (X, 0) > 5 -> false */
5582 else
5583 /* MIN (X, 0) > -1 -> X > -1 */
5588 }
5589 }
5590 \f
5591 /* T is an integer expression that is being multiplied, divided, or taken a
5592 modulus (CODE says which and what kind of divide or modulus) by a
5593 constant C. See if we can eliminate that operation by folding it with
5594 other operations already in T. WIDE_TYPE, if non-null, is a type that
5595 should be used for the computation if wider than our type.
5597 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5598 (X * 2) + (Y * 4). We must, however, be assured that either the original
5599 expression would not overflow or that overflow is undefined for the type
5600 in the language in question.
5602 If we return a non-null expression, it is an equivalent form of the
5603 original computation, but need not be in the original type.
5605 We set *STRICT_OVERFLOW_P to true if the return values depends on
5606 signed overflow being undefined. Otherwise we do not change
5607 *STRICT_OVERFLOW_P. */
5609 static tree
5612 {
5613 /* To avoid exponential search depth, refuse to allow recursion past
5614 three levels. Beyond that (1) it's highly unlikely that we'll find
5615 something interesting and (2) we've probably processed it before
5616 when we built the inner expression. */
5619 tree ret;
5624 depth++;
5626 depth--;
5629 }
5631 static tree
5634 {
5645 /* Don't deal with constants of zero here; they confuse the code below. */
5655 /* Note that we need not handle conditional operations here since fold
5656 already handles those cases. So just do arithmetic here. */
5658 {
5660 /* For a constant, we can always simplify if we are a multiply
5661 or (for divide and modulus) if it is a multiple of our constant. */
5669 /* If op0 is an expression ... */
5675 /* ... and has wrapping overflow, and its type is smaller
5676 than ctype, then we cannot pass through as widening. */
5680 /* ... or this is a truncation (t is narrower than op0),
5681 then we cannot pass through this narrowing. */
5684 /* ... or signedness changes for division or modulus,
5685 then we cannot pass through this conversion. */
5689 /* ... or has undefined overflow while the converted to
5690 type has not, we cannot do the operation in the inner type
5691 as that would introduce undefined overflow. */
5696 /* Pass the constant down and see if we can make a simplification. If
5697 we can, replace this expression with the inner simplification for
5698 possible later conversion to our or some other type. */
5703 code == MULT_EXPR
5705 strict_overflow_p))))
5710 /* If widening the type changes it from signed to unsigned, then we
5711 must avoid building ABS_EXPR itself as unsigned. */
5713 {
5717 {
5720 }
5722 }
5723 /* If the constant is negative, we cannot simplify this. */
5726 /* FALLTHROUGH */
5728 /* For division and modulus, type can't be unsigned, as e.g.
5729 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
5730 For signed types, even with wrapping overflow, this is fine. */
5739 /* If widening the type changes the signedness, then we can't perform
5740 this optimization as that changes the result. */
5744 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5750 {
5757 }
5761 /* If the second operand is constant, this is a multiplication
5762 or floor division, by a power of two, so we can treat it that
5763 way unless the multiplier or divisor overflows. Signed
5764 left-shift overflow is implementation-defined rather than
5765 undefined in C90, so do not convert signed left shift into
5766 multiplication. */
5769 /* const_binop may not detect overflow correctly,
5770 so check for it explicitly here. */
5774 size_one_node,
5775 op1)))
5779 ctype,
5781 t1),
5786 /* See if we can eliminate the operation on both sides. If we can, we
5787 can return a new PLUS or MINUS. If we can't, the only remaining
5788 cases where we can do anything are if the second operand is a
5789 constant. */
5795 /* If not multiplication, we can only do this if both operands
5796 are divisible by c. */
5799 {
5804 }
5806 /* If this was a subtraction, negate OP1 and set it to be an addition.
5807 This simplifies the logic below. */
5809 {
5811 /* If OP1 was not easily negatable, the constant may be OP0. */
5813 {
5820 }
5821 }
5826 /* If either OP1 or C are negative, this optimization is not safe for
5827 some of the division and remainder types while for others we need
5828 to change the code. */
5830 {
5838 }
5840 /* If it's a multiply or a division/modulus operation of a multiple
5841 of our constant, do the operation and verify it doesn't overflow. */
5844 {
5847 /* We allow the constant to overflow with wrapping semantics. */
5851 }
5852 else
5855 /* If we have an unsigned type, we cannot widen the operation since it
5856 will change the result if the original computation overflowed. */
5860 /* If we were able to eliminate our operation from the first side,
5861 apply our operation to the second side and reform the PLUS. */
5865 /* The last case is if we are a multiply. In that case, we can
5866 apply the distributive law to commute the multiply and addition
5867 if the multiplication of the constants doesn't overflow
5868 and overflow is defined. With undefined overflow
5869 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
5875 op1);
5880 /* We have a special case here if we are doing something like
5881 (C * 8) % 4 since we know that's zero. */
5884 /* If the multiplication can overflow we cannot optimize this. */
5888 {
5891 }
5893 /* ... fall through ... */
5897 /* If we can extract our operation from the LHS, do so and return a
5898 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5899 do something only if the second operand is a constant. */
5913 /* If these are the same operation types, we can associate them
5914 assuming no overflow. */
5916 {
5928 }
5930 /* If these operations "cancel" each other, we have the main
5931 optimizations of this pass, which occur when either constant is a
5932 multiple of the other, in which case we replace this with either an
5933 operation or CODE or TCODE.
5935 If we have an unsigned type, we cannot do this since it will change
5936 the result if the original computation overflowed. */
5943 {
5945 {
5952 }
5954 {
5961 }
5962 }
5967 }
5970 }
5971 \f
5972 /* Return a node which has the indicated constant VALUE (either 0 or
5973 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
5974 and is of the indicated TYPE. */
5976 tree
5978 {
5987 else
5989 }
5992 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
5993 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
5994 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
5995 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
5996 COND is the first argument to CODE; otherwise (as in the example
5997 given here), it is the second argument. TYPE is the type of the
5998 original expression. Return NULL_TREE if no simplification is
5999 possible. */
6001 static tree
6006 {
6016 {
6020 /* If this operand throws an expression, then it does not make
6021 sense to try to perform a logical or arithmetic operation
6022 involving it. */
6027 }
6028 else
6029 {
6034 }
6039 /* This transformation is only worthwhile if we don't have to wrap ARG
6040 in a SAVE_EXPR and the operation can be simplified without recursing
6041 on at least one of the branches once its pushed inside the COND_EXPR. */
6050 {
6054 else
6056 }
6058 {
6062 else
6064 }
6066 /* Check that we have simplified at least one of the branches. */
6071 }
6073 \f
6074 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6076 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6077 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6078 ADDEND is the same as X.
6080 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6081 and finite. The problematic cases are when X is zero, and its mode
6082 has signed zeros. In the case of rounding towards -infinity,
6083 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6084 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6086 bool
6088 {
6092 /* Don't allow the fold with -fsignaling-nans. */
6096 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6100 /* In a vector or complex, we would need to check the sign of all zeros. */
6104 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6108 /* The mode has signed zeros, and we have to honor their sign.
6109 In this situation, there is only one case we can return true for.
6110 X - 0 is the same as X unless rounding towards -infinity is
6111 supported. */
6113 }
6115 /* Subroutine of fold() that checks comparisons of built-in math
6116 functions against real constants.
6118 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6119 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6120 is the type of the result and ARG0 and ARG1 are the operands of the
6121 comparison. ARG1 must be a TREE_REAL_CST.
6123 The function returns the constant folded tree if a simplification
6124 can be made, and NULL_TREE otherwise. */
6126 static tree
6130 {
6131 REAL_VALUE_TYPE c;
6134 {
6140 {
6141 /* sqrt(x) < y is always false, if y is negative. */
6145 /* sqrt(x) > y is always true, if y is negative and we
6146 don't care about NaNs, i.e. negative values of x. */
6150 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6153 }
6155 {
6156 REAL_VALUE_TYPE c2;
6162 {
6163 /* sqrt(x) > y is x == +Inf, when y is very large. */
6168 /* sqrt(x) > y is always false, when y is very large
6169 and we don't care about infinities. */
6171 }
6173 /* sqrt(x) > c is the same as x > c*c. */
6176 }
6178 {
6179 REAL_VALUE_TYPE c2;
6185 {
6186 /* sqrt(x) < y is always true, when y is a very large
6187 value and we don't care about NaNs or Infinities. */
6191 /* sqrt(x) < y is x != +Inf when y is very large and we
6192 don't care about NaNs. */
6197 /* sqrt(x) < y is x >= 0 when y is very large and we
6198 don't care about Infinities. */
6203 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6208 dconst0)),
6211 c2)));
6212 }
6214 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6219 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6224 dconst0)),
6227 c2)));
6228 }
6229 }
6232 }
6234 /* Subroutine of fold() that optimizes comparisons against Infinities,
6235 either +Inf or -Inf.
6237 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6238 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6239 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6241 The function returns the constant folded tree if a simplification
6242 can be made, and NULL_TREE otherwise. */
6244 static tree
6247 {
6248 machine_mode mode;
6249 REAL_VALUE_TYPE max;
6250 tree temp;
6255 /* For negative infinity swap the sense of the comparison. */
6261 {
6263 /* x > +Inf is always false, if with ignore sNANs. */
6269 /* x <= +Inf is always true, if we don't case about NaNs. */
6273 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6279 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6285 /* x < +Inf is always equal to x <= DBL_MAX. */
6291 /* x != +Inf is always equal to !(x > DBL_MAX). */
6303 }
6306 }
6308 /* Subroutine of fold() that optimizes comparisons of a division by
6309 a nonzero integer constant against an integer constant, i.e.
6310 X/C1 op C2.
6312 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6313 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6314 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6316 The function returns the constant folded tree if a simplification
6317 can be made, and NULL_TREE otherwise. */
6319 static tree
6322 {
6330 /* We have to do this the hard way to detect unsigned overflow.
6331 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6337 {
6342 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6346 }
6348 {
6352 {
6371 }
6372 }
6373 else
6374 {
6375 /* A negative divisor reverses the relational operators. */
6381 {
6400 }
6401 }
6404 {
6425 {
6428 }
6433 {
6436 }
6441 {
6444 }
6449 {
6452 }
6457 }
6460 }
6463 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6464 equality/inequality test, then return a simplified form of the test
6465 using a sign testing. Otherwise return NULL. TYPE is the desired
6466 result type. */
6468 static tree
6471 tree result_type)
6472 {
6473 /* If this is testing a single bit, we can optimize the test. */
6477 {
6478 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6479 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6483 /* This is only a win if casting to a signed type is cheap,
6484 i.e. when arg00's type is not a partial mode. */
6487 {
6490 result_type,
6493 }
6494 }
6497 }
6499 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6500 equality/inequality test, then return a simplified form of
6501 the test using shifts and logical operations. Otherwise return
6502 NULL. TYPE is the desired result type. */
6504 tree
6507 {
6508 /* If this is testing a single bit, we can optimize the test. */
6512 {
6521 /* First, see if we can fold the single bit test into a sign-bit
6522 test. */
6524 result_type);
6528 /* Otherwise we have (A & C) != 0 where C is a single bit,
6529 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6530 Similarly for (A & C) == 0. */
6532 /* If INNER is a right shift of a constant and it plus BITNUM does
6533 not overflow, adjust BITNUM and INNER. */
6539 {
6542 }
6544 /* If we are going to be able to omit the AND below, we must do our
6545 operations as unsigned. If we must use the AND, we have a choice.
6546 Normally unsigned is faster, but for some machines signed is. */
6547 #ifdef LOAD_EXTEND_OP
6550 #else
6552 #endif
6568 /* Put the AND last so it can combine with more things. */
6571 /* Make sure to return the proper type. */
6575 }
6577 }
6579 /* Check whether we are allowed to reorder operands arg0 and arg1,
6580 such that the evaluation of arg1 occurs before arg0. */
6582 static bool
6584 {
6591 }
6593 /* Test whether it is preferable two swap two operands, ARG0 and
6594 ARG1, for example because ARG0 is an integer constant and ARG1
6595 isn't. If REORDER is true, only recommend swapping if we can
6596 evaluate the operands in reverse order. */
6598 bool
6600 {
6618 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6619 for commutative and comparison operators. Ensuring a canonical
6620 form allows the optimizers to find additional redundancies without
6621 having to explicitly check for both orderings. */
6627 /* Put SSA_NAMEs last. */
6633 /* Put variables last. */
6640 }
6642 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6643 ARG0 is extended to a wider type. */
6645 static tree
6648 {
6650 tree arg1_unw;
6659 #ifdef HAVE_canonicalize_funcptr_for_compare
6660 /* Disable this optimization if we're casting a function pointer
6661 type on targets that require function pointer canonicalization. */
6666 #endif
6673 /* If possible, express the comparison in the shorter mode. */
6693 /* If we are comparing with the integer that does not fit into the range
6694 of the shorter type, the result is known. */
6705 {
6732 }
6735 }
6737 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6738 ARG0 just the signedness is changed. */
6740 static tree
6743 {
6744 tree arg0_inner;
6754 #ifdef HAVE_canonicalize_funcptr_for_compare
6755 /* Disable this optimization if we're casting a function pointer
6756 type on targets that require function pointer canonicalization. */
6761 #endif
6782 else
6786 }
6789 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6790 means A >= Y && A != MAX, but in this case we know that
6791 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6793 static tree
6795 {
6802 else
6811 {
6814 }
6816 {
6819 }
6820 else
6827 {
6828 /* Convert the pointer types into integer before taking the difference. */
6832 }
6833 else
6840 }
6842 /* Fold a sum or difference of at least one multiplication.
6843 Returns the folded tree or NULL if no simplification could be made. */
6845 static tree
6848 {
6852 /* (A * C) +- (B * C) -> (A+-B) * C.
6853 (A * C) +- A -> A * (C+-1).
6854 We are most concerned about the case where C is a constant,
6855 but other combinations show up during loop reduction. Since
6856 it is not difficult, try all four possibilities. */
6859 {
6862 }
6864 {
6867 }
6868 else
6869 {
6870 /* We cannot generate constant 1 for fract. */
6875 }
6877 {
6880 }
6882 {
6884 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6885 the purpose of this canonicalization. */
6889 {
6892 }
6893 else
6895 }
6896 else
6897 {
6898 /* We cannot generate constant 1 for fract. */
6903 }
6915 /* No identical multiplicands; see if we can find a common
6916 power-of-two factor in non-power-of-two multiplies. This
6917 can help in multi-dimensional array access. */
6920 {
6923 tree maybe_same;
6927 /* Move min of absolute values to int11. */
6929 {
6934 }
6935 else
6939 /* The remainder should not be a constant, otherwise we
6940 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6941 increased the number of multiplications necessary. */
6943 {
6951 }
6952 }
6962 }
6964 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6965 specified by EXPR into the buffer PTR of length LEN bytes.
6966 Return the number of bytes placed in the buffer, or zero
6967 upon failure. */
6969 static int
6971 {
6985 {
6987 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
6988 number of bytes. */
6992 {
6999 else
7001 }
7002 else
7007 }
7009 }
7012 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7013 specified by EXPR into the buffer PTR of length LEN bytes.
7014 Return the number of bytes placed in the buffer, or zero
7015 upon failure. */
7017 static int
7019 {
7023 FIXED_VALUE_TYPE value;
7039 }
7042 /* Subroutine of native_encode_expr. Encode the REAL_CST
7043 specified by EXPR into the buffer PTR of length LEN bytes.
7044 Return the number of bytes placed in the buffer, or zero
7045 upon failure. */
7047 static int
7049 {
7055 /* There are always 32 bits in each long, no matter the size of
7056 the hosts long. We handle floating point representations with
7057 up to 192 bits. */
7071 {
7076 {
7083 else
7085 }
7086 else
7092 }
7094 }
7096 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7097 specified by EXPR into the buffer PTR of length LEN bytes.
7098 Return the number of bytes placed in the buffer, or zero
7099 upon failure. */
7101 static int
7103 {
7105 tree part;
7120 }
7123 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7124 specified by EXPR into the buffer PTR of length LEN bytes.
7125 Return the number of bytes placed in the buffer, or zero
7126 upon failure. */
7128 static int
7130 {
7140 {
7142 {
7145 }
7156 }
7158 }
7161 /* Subroutine of native_encode_expr. Encode the STRING_CST
7162 specified by EXPR into the buffer PTR of length LEN bytes.
7163 Return the number of bytes placed in the buffer, or zero
7164 upon failure. */
7166 static int
7168 {
7170 HOST_WIDE_INT total_bytes;
7184 {
7187 {
7190 }
7193 }
7194 else
7197 }
7200 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7201 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7202 buffer PTR of length LEN bytes. If OFF is not -1 then start
7203 the encoding at byte offset OFF and encode at most LEN bytes.
7204 Return the number of bytes placed in the buffer, or zero upon failure. */
7206 int
7208 {
7210 {
7231 }
7232 }
7235 /* Subroutine of native_interpret_expr. Interpret the contents of
7236 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7237 If the buffer cannot be interpreted, return NULL_TREE. */
7239 static tree
7241 {
7251 }
7254 /* Subroutine of native_interpret_expr. Interpret the contents of
7255 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7256 If the buffer cannot be interpreted, return NULL_TREE. */
7258 static tree
7260 {
7262 double_int result;
7263 FIXED_VALUE_TYPE fixed_value;
7273 }
7276 /* Subroutine of native_interpret_expr. Interpret the contents of
7277 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7278 If the buffer cannot be interpreted, return NULL_TREE. */
7280 static tree
7282 {
7287 /* There are always 32 bits in each long, no matter the size of
7288 the hosts long. We handle floating point representations with
7289 up to 192 bits. */
7290 REAL_VALUE_TYPE r;
7301 {
7304 {
7311 else
7313 }
7314 else
7319 }
7323 }
7326 /* Subroutine of native_interpret_expr. Interpret the contents of
7327 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7328 If the buffer cannot be interpreted, return NULL_TREE. */
7330 static tree
7332 {
7347 }
7350 /* Subroutine of native_interpret_expr. Interpret the contents of
7351 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7352 If the buffer cannot be interpreted, return NULL_TREE. */
7354 static tree
7356 {
7369 {
7374 }
7376 }
7379 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7380 the buffer PTR of length LEN as a constant of type TYPE. For
7381 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7382 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7383 return NULL_TREE. */
7385 tree
7387 {
7389 {
7411 }
7412 }
7414 /* Returns true if we can interpret the contents of a native encoding
7415 as TYPE. */
7417 static bool
7419 {
7421 {
7434 }
7435 }
7437 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7438 TYPE at compile-time. If we're unable to perform the conversion
7439 return NULL_TREE. */
7441 static tree
7443 {
7444 /* We support up to 512-bit values (for V8DFmode). */
7448 /* Check that the host and target are sane. */
7457 }
7459 /* Build an expression for the address of T. Folds away INDIRECT_REF
7460 to avoid confusing the gimplify process. */
7462 tree
7464 {
7465 /* The size of the object is not relevant when talking about its address. */
7470 {
7475 }
7485 {
7490 }
7491 else
7495 }
7497 /* Build an expression for the address of T. */
7499 tree
7501 {
7505 }
7509 /* Fold a unary expression of code CODE and type TYPE with operand
7510 OP0. Return the folded expression if folding is successful.
7511 Otherwise, return NULL_TREE. */
7513 tree
7515 {
7516 tree tem;
7517 tree arg0;
7529 {
7532 {
7533 /* Don't use STRIP_NOPS, because signedness of argument type
7534 matters. */
7536 }
7537 else
7538 {
7539 /* Strip any conversions that don't change the mode. This
7540 is safe for every expression, except for a comparison
7541 expression because its signedness is derived from its
7542 operands.
7544 Note that this is done as an internal manipulation within
7545 the constant folder, in order to find the simplest
7546 representation of the arguments so that their form can be
7547 studied. In any cases, the appropriate type conversions
7548 should be put back in the tree that will get out of the
7549 constant folder. */
7551 }
7552 }
7555 {
7562 {
7576 /* If this was a conversion, and all we did was to move into
7577 inside the COND_EXPR, bring it back out. But leave it if
7578 it is a conversion from integer to integer and the
7579 result precision is no wider than a word since such a
7580 conversion is cheap and may be optimized away by combine,
7581 while it couldn't if it were outside the COND_EXPR. Then return
7582 so we don't get into an infinite recursion loop taking the
7583 conversion out and then back in. */
7595 && (INTEGRAL_TYPE_P
7608 }
7609 }
7612 {
7618 CASE_CONVERT:
7622 {
7623 /* If we have (type) (a CMP b) and type is an integral type, return
7624 new expression involving the new type. Canonicalize
7625 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7626 non-integral type.
7627 Do not fold the result as that would not simplify further, also
7628 folding again results in recursions. */
7638 }
7640 /* Handle (T *)&A.B.C for A being of type T and B and C
7641 living at offset zero. This occurs frequently in
7642 C++ upcasting and then accessing the base. */
7646 {
7648 tree offset;
7649 machine_mode mode;
7654 /* If the reference was to a (constant) zero offset, we can use
7655 the address of the base if it has the same base type
7656 as the result type and the pointer type is unqualified. */
7663 }
7667 /* Detect assigning a bitfield. */
7669 && DECL_BIT_FIELD
7671 {
7672 /* Don't leave an assignment inside a conversion
7673 unless assigning a bitfield. */
7675 /* First do the assignment, then return converted constant. */
7680 }
7682 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7683 constants (if x has signed type, the sign bit cannot be set
7684 in c). This folds extension into the BIT_AND_EXPR.
7685 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7686 very likely don't have maximal range for their precision and this
7687 transformation effectively doesn't preserve non-maximal ranges. */
7691 {
7702 <= HOST_BITS_PER_WIDE_INT
7704 {
7708 cst &= HOST_WIDE_INT_M1U
7711 #ifdef LOAD_EXTEND_OP
7713 && !flag_syntax_only
7716 {
7720 }
7721 #endif
7722 }
7724 {
7729 }
7730 }
7732 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7733 when one of the new casts will fold away. Conservatively we assume
7734 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7741 {
7745 return fold_build_pointer_plus_loc
7747 }
7749 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7750 of the same precision, and X is an integer type not narrower than
7751 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7757 {
7763 }
7765 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7766 type of X and Y (integer types only). */
7771 {
7772 /* Be careful not to introduce new overflows. */
7773 tree mult_type;
7776 else
7780 {
7787 }
7788 }
7818 /* Convert fabs((double)float) into (double)fabsf(float). */
7821 {
7827 targ0));
7828 }
7829 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
7833 /* Strip sign ops from argument. */
7835 {
7840 }
7847 {
7853 }
7855 {
7860 }
7868 /* Convert ~ (-A) to A - 1. */
7873 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
7882 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7897 /* Perform BIT_NOT_EXPR on each element individually. */
7899 {
7901 tree elem;
7906 {
7912 }
7915 }
7920 /* Note that the operand of this must be an int
7921 and its values must be 0 or 1.
7922 ("true" is a fixed value perhaps depending on the language,
7923 but we don't handle values other than 1 correctly yet.) */
7935 {
7943 }
7945 {
7950 }
7952 {
7956 {
7965 }
7966 }
7975 {
7983 }
7985 {
7989 }
7991 {
7995 {
8004 }
8005 }
8009 /* Fold *&X to X if X is an lvalue. */
8011 {
8018 }
8025 {
8044 else
8048 {
8052 }
8055 }
8060 {
8074 {
8079 }
8082 {
8086 }
8089 }
8094 }
8097 /* If the operation was a conversion do _not_ mark a resulting constant
8098 with TREE_OVERFLOW if the original constant was not. These conversions
8099 have implementation defined behavior and retaining the TREE_OVERFLOW
8100 flag here would confuse later passes such as VRP. */
8101 tree
8104 {
8113 }
8115 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8116 operands OP0 and OP1. LOC is the location of the resulting expression.
8117 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8118 Return the folded expression if folding is successful. Otherwise,
8119 return NULL_TREE. */
8120 static tree
8123 {
8124 tree tem;
8126 /* We only do these simplifications if we are optimizing. */
8130 /* Check for things like (A || B) && (A || C). We can convert this
8131 to A || (B && C). Note that either operator can be any of the four
8132 truth and/or operations and the transformation will still be
8133 valid. Also note that we only care about order for the
8134 ANDIF and ORIF operators. If B contains side effects, this
8135 might change the truth-value of A. */
8142 {
8162 /* This case if tricky because we must either have commutative
8163 operators or else A10 must not have side-effects. */
8169 a01);
8170 }
8172 /* See if we can build a range comparison. */
8178 {
8182 }
8186 {
8190 }
8192 /* Check for the possibility of merging component references. If our
8193 lhs is another similar operation, try to merge its rhs with our
8194 rhs. Then try to merge our lhs and rhs. */
8208 {
8215 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8216 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8217 We don't want to pack more than two leafs to a non-IF AND/OR
8218 expression.
8219 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8220 equal to IF-CODE, then we don't want to add right-hand operand.
8221 If the inner right-hand side of left-hand operand has
8222 side-effects, or isn't simple, then we can't add to it,
8223 as otherwise we might destroy if-sequence. */
8226 /* Needed for sequence points to handle trappings, and
8227 side-effects. */
8229 {
8231 arg1);
8233 tem);
8234 }
8235 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8236 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8239 /* Needed for sequence points to handle trappings, and
8240 side-effects. */
8242 {
8247 }
8248 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8249 into (A OR B).
8250 For sequence point consistancy, we need to check for trapping,
8251 and side-effects. */
8255 }
8258 }
8260 /* Fold a binary expression of code CODE and type TYPE with operands
8261 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8262 Return the folded expression if folding is successful. Otherwise,
8263 return NULL_TREE. */
8265 static tree
8267 {
8274 else
8277 /* MIN (MAX (a, b), b) == b. */
8282 /* MIN (MAX (b, a), b) == b. */
8288 /* MIN (a, MAX (a, b)) == a. */
8294 /* MIN (a, MAX (b, a)) == a. */
8301 }
8303 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8304 by changing CODE to reduce the magnitude of constants involved in
8305 ARG0 of the comparison.
8306 Returns a canonicalized comparison tree if a simplification was
8307 possible, otherwise returns NULL_TREE.
8308 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8309 valid if signed overflow is undefined. */
8311 static tree
8315 {
8321 /* Match A +- CST code arg1 and CST code arg1. We can change the
8322 first form only if overflow is undefined. */
8324 /* In principle pointers also have undefined overflow behavior,
8325 but that causes problems elsewhere. */
8333 /* Identify the constant in arg0 and its sign. */
8336 else
8340 /* Overflowed constants and zero will cause problems. */
8345 /* See if we can reduce the magnitude of the constant in
8346 arg0 by changing the comparison code. */
8348 {
8349 /* CST <= arg1 -> CST-1 < arg1. */
8352 /* -CST < arg1 -> -CST-1 <= arg1. */
8355 /* CST > arg1 -> CST-1 >= arg1. */
8358 /* -CST >= arg1 -> -CST-1 > arg1. */
8361 else
8363 /* arg1 code' CST' might be more canonical. */
8365 }
8366 else
8367 {
8368 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8372 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8376 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8380 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8384 else
8387 }
8389 /* Now build the constant reduced in magnitude. But not if that
8390 would produce one outside of its types range. */
8398 /* We cannot swap the comparison here as that would cause us to
8399 endlessly recurse. */
8408 /* If swapping might yield to a more canonical form, do so. */
8411 else
8413 }
8415 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8416 overflow further. Try to decrease the magnitude of constants involved
8417 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8418 and put sole constants at the second argument position.
8419 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8421 static tree
8424 {
8425 tree t;
8430 /* Try canonicalization by simplifying arg0. */
8435 {
8439 }
8441 /* Try canonicalization by simplifying arg1 using the swapped
8442 comparison. */
8450 }
8452 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8453 space. This is used to avoid issuing overflow warnings for
8454 expressions like &p->x which can not wrap. */
8456 static bool
8458 {
8465 wide_int wi_offset;
8471 else
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 /* Return the HOST_WIDE_INT least significant bits of T, a sizetype
8502 kind INTEGER_CST. This makes sure to properly sign-extend the
8503 constant. */
8505 static HOST_WIDE_INT
8507 {
8513 }
8515 /* Subroutine of fold_binary. This routine performs all of the
8516 transformations that are common to the equality/inequality
8517 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8518 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8519 fold_binary should call fold_binary. Fold a comparison with
8520 tree code CODE and type TYPE with operands OP0 and OP1. Return
8521 the folded comparison or NULL_TREE. */
8523 static tree
8526 {
8536 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1. */
8543 {
8544 const enum tree_code
8551 /* If the constant operation overflowed this can be
8552 simplified as a comparison against INT_MAX/INT_MIN. */
8555 {
8559 /* Get the sign of the constant on the lhs if the
8560 operation were VARIABLE + CONST1. */
8564 /* The sign of the constant determines if we overflowed
8565 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8566 Canonicalize to the INT_MIN overflow by swapping the comparison
8567 if necessary. */
8571 /* We now can look at the canonicalized case
8572 VARIABLE + 1 CODE2 INT_MIN
8573 and decide on the result. */
8575 {
8579 return
8585 return
8590 }
8591 }
8592 else
8593 {
8596 "when changing X +- C1 cmp C2 to "
8598 WARN_STRICT_OVERFLOW_COMPARISON);
8600 }
8601 }
8603 /* Transform comparisons of the form X - Y CMP 0 to X CMP Y. */
8605 && equality_code
8607 {
8608 /* ??? The transformation is valid for the other operators if overflow
8609 is undefined for the type, but performing it here badly interacts
8610 with the transformation in fold_cond_expr_with_comparison which
8611 attempts to synthetize ABS_EXPR. */
8615 WARN_STRICT_OVERFLOW_COMPARISON);
8618 }
8620 /* For comparisons of pointers we can decompose it to a compile time
8621 comparison of the base objects and the offsets into the object.
8622 This requires at least one operand being an ADDR_EXPR or a
8623 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8629 {
8632 machine_mode mode;
8636 /* Get base and offset for the access. Strip ADDR_EXPR for
8637 get_inner_reference, but put it back by stripping INDIRECT_REF
8638 off the base object if possible. indirect_baseN will be true
8639 if baseN is not an address but refers to the object itself. */
8642 {
8648 else
8650 }
8652 {
8656 {
8659 }
8662 {
8667 {
8670 }
8671 }
8672 }
8676 {
8682 else
8684 }
8686 {
8690 {
8693 }
8696 {
8701 {
8704 }
8705 }
8706 }
8708 /* A local variable can never be pointed to by
8709 the default SSA name of an incoming parameter. */
8711 && indirect_base0
8714 && !indirect_base1
8719 && indirect_base1
8722 && !indirect_base0
8726 {
8731 }
8732 /* If we have equivalent bases we might be able to simplify. */
8735 {
8736 /* We can fold this expression to a constant if the non-constant
8737 offset parts are equal. */
8746 {
8752 "occur when comparing P +- C1 with "
8754 WARN_STRICT_OVERFLOW_CONDITIONAL);
8757 {
8771 }
8772 }
8773 /* We can simplify the comparison to a comparison of the variable
8774 offset parts if the constant offset parts are equal.
8775 Be careful to use signed sizetype here because otherwise we
8776 mess with array offsets in the wrong way. This is possible
8777 because pointer arithmetic is restricted to retain within an
8778 object and overflow on pointer differences is undefined as of
8779 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8781 && (equality_code
8784 {
8785 /* By converting to signed sizetype we cover middle-end pointer
8786 arithmetic which operates on unsigned pointer types of size
8787 type size and ARRAY_REF offsets which are properly sign or
8788 zero extended from their type in case it is narrower than
8789 sizetype. */
8792 else
8796 else
8803 "occur when comparing P +- C1 with "
8805 WARN_STRICT_OVERFLOW_COMPARISON);
8808 }
8809 }
8810 /* For non-equal bases we can simplify if they are addresses
8811 of local binding decls or constants. */
8813 /* We know that !operand_equal_p (base0, base1, 0)
8814 because the if condition was false. But make
8815 sure two decls are not the same. */
8829 {
8836 }
8837 /* For equal offsets we can simplify to a comparison of the
8838 base addresses. */
8840 && (indirect_base0
8842 && (indirect_base1
8847 {
8853 }
8854 }
8856 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8857 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8858 the resulting offset is smaller in absolute value than the
8859 original one and has the same sign. */
8867 {
8872 tree cst;
8874 "occur when combining constants around "
8877 /* Put the constant on the side where it doesn't overflow and is
8878 of lower absolute value and of same sign than before. */
8885 {
8888 variable1,
8892 }
8900 {
8906 variable2);
8907 }
8908 }
8910 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8911 signed arithmetic case. That form is created by the compiler
8912 often enough for folding it to be of value. One example is in
8913 computing loop trip counts after Operator Strength Reduction. */
8919 {
8925 /* Handle unfolded multiplication by zero. */
8930 "eliminating multiplication in comparison "
8932 WARN_STRICT_OVERFLOW_COMPARISON);
8934 /* If const1 is negative we swap the sense of the comparison. */
8939 }
8946 {
8954 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8960 /* (-a) CMP (-b) -> b CMP a */
8967 {
8968 REAL_VALUE_TYPE cst;
8971 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8978 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8979 /* a CMP (-0) -> a CMP 0 */
8984 /* x != NaN is always true, other ops are always false. */
8987 {
8990 }
8992 /* Fold comparisons against infinity. */
8995 {
8999 }
9000 }
9002 /* If this is a comparison of a real constant with a PLUS_EXPR
9003 or a MINUS_EXPR of a real constant, we can convert it into a
9004 comparison with a revised real constant as long as no overflow
9005 occurs when unsafe_math_optimizations are enabled. */
9017 /* Likewise, we can simplify a comparison of a real constant with
9018 a MINUS_EXPR whose first operand is also a real constant, i.e.
9019 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9020 floating-point types only if -fassociative-math is set. */
9026 arg1))
9031 /* Fold comparisons against built-in math functions. */
9033 && flag_unsafe_math_optimizations
9035 {
9039 {
9043 }
9044 }
9045 }
9049 {
9050 /* If we are widening one operand of an integer comparison,
9051 see if the other operand is similarly being widened. Perhaps we
9052 can do the comparison in the narrower type. */
9057 /* Or if we are changing signedness. */
9061 }
9063 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9064 constant, we can simplify it. */
9069 {
9073 }
9075 /* Simplify comparison of something with itself. (For IEEE
9076 floating-point, we can only do some of these simplifications.) */
9078 {
9080 {
9095 /* For NE, we can only do this simplification if integer
9096 or we don't honor IEEE floating point NaNs. */
9100 /* ... fall through ... */
9106 }
9107 }
9109 /* If we are comparing an expression that just has comparisons
9110 of two integer values, arithmetic expressions of those comparisons,
9111 and constants, we can simplify it. There are only three cases
9112 to check: the two values can either be equal, the first can be
9113 greater, or the second can be greater. Fold the expression for
9114 those three values. Since each value must be 0 or 1, we have
9115 eight possibilities, each of which corresponds to the constant 0
9116 or 1 or one of the six possible comparisons.
9118 This handles common cases like (a > b) == 0 but also handles
9119 expressions like ((x > y) - (y > x)) > 0, which supposedly
9120 occur in macroized code. */
9123 {
9128 /* Don't handle degenerate cases here; they should already
9129 have been handled anyway. */
9138 {
9142 /* We can't just pass T to eval_subst in case cval1 or cval2
9143 was the same as ARG1. */
9145 tree high_result
9149 arg1);
9150 tree equal_result
9154 arg1);
9155 tree low_result
9159 arg1);
9161 /* All three of these results should be 0 or 1. Confirm they are.
9162 Then use those values to select the proper code to use. */
9167 {
9168 /* Make a 3-bit mask with the high-order bit being the
9169 value for `>', the next for '=', and the low for '<'. */
9173 {
9175 /* Always false. */
9196 /* Always true. */
9198 }
9201 {
9205 }
9207 }
9208 }
9209 }
9211 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9212 into a single range test. */
9220 {
9224 }
9226 /* Fold ~X op ~Y as Y op X. */
9229 {
9235 }
9237 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9240 {
9246 }
9249 }
9252 /* Subroutine of fold_binary. Optimize complex multiplications of the
9253 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9254 argument EXPR represents the expression "z" of type TYPE. */
9256 static tree
9258 {
9263 {
9266 }
9268 {
9271 }
9272 else
9273 {
9277 }
9286 }
9289 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9290 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9291 guarantees that P and N have the same least significant log2(M) bits.
9292 N is not otherwise constrained. In particular, N is not normalized to
9293 0 <= N < M as is common. In general, the precise value of P is unknown.
9294 M is chosen as large as possible such that constant N can be determined.
9296 Returns M and sets *RESIDUE to N.
9298 If ALLOW_FUNC_ALIGN is true, do take functions' DECL_ALIGN_UNIT into
9299 account. This is not always possible due to PR 35705.
9300 */
9302 static unsigned HOST_WIDE_INT
9305 {
9312 {
9317 }
9319 {
9327 allow_func_align);
9333 {
9336 }
9338 {
9341 {
9344 /* Compute the greatest power-of-2 divisor of op1. */
9348 /* If align is non-zero and less than *modulus, replace
9349 *modulus with align., If align is 0, then either op1 is 0
9350 or the greatest power-of-2 divisor of op1 doesn't fit in an
9351 unsigned HOST_WIDE_INT. In either case, no additional
9352 constraint is imposed. */
9357 }
9358 }
9359 }
9361 /* If we get here, we were unable to determine anything useful about the
9362 expression. */
9364 }
9366 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
9367 CONSTRUCTOR ARG into array ELTS and return true if successful. */
9369 static bool
9371 {
9375 {
9378 }
9380 {
9386 else
9388 }
9389 else
9395 }
9397 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9398 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9399 NULL_TREE otherwise. */
9401 static tree
9403 {
9420 {
9424 }
9427 {
9433 }
9434 else
9436 }
9438 /* Try to fold a pointer difference of type TYPE two address expressions of
9439 array references AREF0 and AREF1 using location LOC. Return a
9440 simplified expression for the difference or NULL_TREE. */
9442 static tree
9445 {
9450 /* If the bases are array references as well, recurse. If the bases
9451 are pointer indirections compute the difference of the pointers.
9452 If the bases are equal, we are set. */
9455 && (base_offset
9463 {
9469 base_offset,
9472 }
9474 }
9476 /* If the real or vector real constant CST of type TYPE has an exact
9477 inverse, return it, else return NULL. */
9479 tree
9481 {
9482 REAL_VALUE_TYPE r;
9484 machine_mode mode;
9488 {
9504 {
9509 }
9515 }
9516 }
9518 /* Mask out the tz least significant bits of X of type TYPE where
9519 tz is the number of trailing zeroes in Y. */
9520 static wide_int
9522 {
9527 }
9529 /* Return true when T is an address and is known to be nonzero.
9530 For floating point we further ensure that T is not denormal.
9531 Similar logic is present in nonzero_address in rtlanal.h.
9533 If the return value is based on the assumption that signed overflow
9534 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9535 change *STRICT_OVERFLOW_P. */
9537 static bool
9539 {
9543 /* Doing something useful for floating point would need more work. */
9549 {
9552 strict_overflow_p);
9558 strict_overflow_p);
9566 }
9569 {
9572 strict_overflow_p);
9580 strict_overflow_p);
9595 strict_overflow_p);
9599 strict_overflow_p);
9602 {
9614 }
9618 }
9620 }
9622 /* Return true when T is an address and is known to be nonzero.
9623 Handle warnings about undefined signed overflow. */
9625 static bool
9627 {
9634 "determining that expression is always "
9636 WARN_STRICT_OVERFLOW_MISC);
9638 }
9640 /* Fold a binary expression of code CODE and type TYPE with operands
9641 OP0 and OP1. LOC is the location of the resulting expression.
9642 Return the folded expression if folding is successful. Otherwise,
9643 return NULL_TREE. */
9645 tree
9648 {
9663 /* Strip any conversions that don't change the mode. This is
9664 safe for every expression, except for a comparison expression
9665 because its signedness is derived from its operands. So, in
9666 the latter case, only strip conversions that don't change the
9667 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9668 preserved.
9670 Note that this is done as an internal manipulation within the
9671 constant folder, in order to find the simplest representation
9672 of the arguments so that their form can be studied. In any
9673 cases, the appropriate type conversions should be put back in
9674 the tree that will get out of the constant folder. */
9677 {
9680 }
9681 else
9682 {
9685 }
9687 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9688 constant but we can't do arithmetic on them. */
9696 {
9698 {
9699 /* Make sure type and arg0 have the same saturating flag. */
9703 }
9706 else
9710 {
9714 }
9715 }
9717 /* If this is a commutative operation, and ARG0 is a constant, move it
9718 to ARG1 to reduce the number of tests below. */
9723 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9724 to ARG1 to reduce the number of tests below. */
9733 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9735 First check for cases where an arithmetic operation is applied to a
9736 compound, conditional, or comparison operation. Push the arithmetic
9737 operation inside the compound or conditional to see if any folding
9738 can then be done. Convert comparison to conditional for this purpose.
9739 The also optimizes non-constant cases that used to be done in
9740 expand_expr.
9742 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9743 one of the operands is a comparison and the other is a comparison, a
9744 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9745 code below would make the expression more complex. Change it to a
9746 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9747 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9760 {
9764 boolean_type_node,
9772 }
9776 {
9778 {
9783 tem);
9784 }
9787 {
9792 tem);
9793 }
9798 {
9804 }
9809 {
9815 }
9816 }
9819 {
9821 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9824 {
9830 }
9832 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9835 {
9836 tree base;
9837 HOST_WIDE_INT coffset;
9846 }
9851 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9857 arg1),
9859 arg0)));
9861 /* PTR_CST +p CST -> CST1 */
9870 {
9871 /* X + (X / CST) * -CST is X % CST. */
9876 {
9885 cst0));
9886 }
9887 }
9889 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9890 one. Make sure the type is not saturating and has the signedness of
9891 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9892 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9899 {
9903 }
9906 {
9907 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9908 with a constant, and the two constants have no bits in common,
9909 we should treat this as a BIT_IOR_EXPR since this may produce more
9910 simplifications. */
9917 {
9920 }
9922 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9923 (plus (plus (mult) (mult)) (foo)) so that we can
9924 take advantage of the factoring cases below. */
9932 {
9938 else
9951 parg0),
9953 marg)),
9957 return
9963 parg1)));
9964 }
9965 }
9966 else
9967 {
9968 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9969 to __complex__ ( x, y ). This is not the same for SNaNs or
9970 if signed zeros are involved. */
9974 {
9981 {
9985 {
9991 }
9993 {
9999 }
10000 }
10001 }
10009 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
10010 We associate floats only if the user has specified
10011 -fassociative-math. */
10015 {
10020 {
10021 tree tree0;
10024 }
10025 }
10026 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
10027 We associate floats only if the user has specified
10028 -fassociative-math. */
10032 {
10037 {
10038 tree tree0;
10041 }
10042 }
10043 }
10045 bit_rotate:
10046 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
10047 is a rotate of A by C1 bits. */
10048 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
10049 is a rotate of A by B bits. */
10050 {
10052 tree rtype;
10061 /* Only create rotates in complete modes. Other cases are not
10062 expanded properly. */
10065 {
10079 {
10085 }
10087 {
10095 element_precision
10099 return
10102 ? LROTATE_EXPR
10106 }
10108 {
10116 element_precision
10120 return fold_convert_loc
10123 ? LROTATE_EXPR
10127 }
10128 }
10129 }
10131 associate:
10132 /* In most languages, can't associate operations on floats through
10133 parentheses. Rather than remember where the parentheses were, we
10134 don't associate floats at all, unless the user has specified
10135 -fassociative-math.
10136 And, we need to make sure type is not saturating. */
10140 {
10146 /* Split both trees into variables, constants, and literals. Then
10147 associate each group together, the constants with literals,
10148 then the result with variables. This increases the chances of
10149 literals being recombined later and of generating relocatable
10150 expressions for the sum of a constant and literal. */
10155 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10159 /* With undefined overflow prefer doing association in a type
10160 which wraps on overflow, if that is one of the operand types. */
10163 {
10171 }
10173 /* With undefined overflow we can only associate constants with one
10174 variable, and constants whose association doesn't overflow. */
10177 {
10179 {
10197 /* The only case we can still associate with two variables
10198 is if they are the same, modulo negation and bit-pattern
10199 preserving conversions. */
10202 }
10203 }
10205 /* Only do something if we found more than two objects. Otherwise,
10206 nothing has changed and we risk infinite recursion. */
10212 {
10224 /* Preserve the MINUS_EXPR if the negative part of the literal is
10225 greater than the positive part. Otherwise, the multiplicative
10226 folding code (i.e extract_muldiv) may be fooled in case
10227 unsigned constants are subtracted, like in the following
10228 example: ((X*2 + 4) - 8U)/2. */
10230 {
10234 {
10238 }
10239 else
10240 {
10244 }
10245 }
10247 /* Don't introduce overflows through reassociation. */
10254 {
10256 return
10260 else
10261 {
10264 return
10268 }
10269 }
10272 return
10275 }
10276 }
10281 /* Pointer simplifications for subtraction, simple reassociations. */
10283 {
10284 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10287 {
10297 }
10298 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10300 {
10307 }
10308 /* PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A, assuming PTR0 - PTR1
10309 simplifies. */
10311 {
10318 arg10);
10321 }
10322 }
10323 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10332 /* Convert -A - 1 to ~A. */
10340 /* Convert -1 - A to ~A. */
10346 /* X - (X / Y) * Y is X % Y. */
10354 return
10360 {
10361 /* Fold A - (A & B) into ~B & A. */
10364 {
10366 {
10373 }
10375 {
10382 }
10383 }
10385 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10386 any power of 2 minus 1. */
10391 {
10397 {
10401 }
10402 }
10403 }
10405 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10406 __complex__ ( x, -y ). This is not the same for SNaNs or if
10407 signed zeros are involved. */
10411 {
10418 {
10422 {
10424 arg1r ? arg1r
10429 }
10431 {
10435 arg1i ? arg1i
10438 }
10439 }
10440 }
10442 /* A - B -> A + (-B) if B is easily negatable. */
10446 /* Avoid this transformation if B is a positive REAL_CST. */
10455 /* Try folding difference of addresses. */
10456 {
10457 HOST_WIDE_INT diff;
10463 }
10465 /* Fold &a[i] - &a[j] to i-j. */
10470 {
10476 }
10479 && flag_unsafe_math_optimizations
10485 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
10486 one. Make sure the type is not saturating and has the signedness of
10487 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10488 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10495 {
10499 }
10504 /* (-A) * (-B) -> A * B */
10519 {
10520 /* Transform x * -C into -x * C if x is easily negatable. */
10529 tem);
10531 /* (a * (1 << b)) is (a << b) */
10541 /* (A + A) * C -> A * 2 * C */
10553 /* ((T) (X /[ex] C)) * C cancels out if the conversion is
10554 sign-changing only. */
10564 {
10567 "occur when simplifying "
10569 WARN_STRICT_OVERFLOW_MISC);
10571 }
10573 /* Optimize z * conj(z) for integer complex numbers. */
10580 }
10581 else
10582 {
10583 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10584 the result for floating point types due to rounding so it is applied
10585 only if -fassociative-math was specify. */
10590 {
10592 arg1);
10596 }
10598 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10600 {
10603 {
10606 }
10607 }
10609 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10610 This is not the same for NaNs or if signed zeros are
10611 involved. */
10617 {
10620 return
10626 return
10631 }
10633 /* Optimize z * conj(z) for floating point complex numbers.
10634 Guarded by flag_unsafe_math_optimizations as non-finite
10635 imaginary components don't produce scalar results. */
10646 {
10650 /* Optimizations of root(...)*root(...). */
10652 {
10657 /* Optimize sqrt(x)*sqrt(x) as x. */
10663 /* Optimize root(x)*root(y) as root(x*y). */
10667 }
10669 /* Optimize expN(x)*expN(y) as expN(x+y). */
10671 {
10677 }
10679 /* Optimizations of pow(...)*pow(...). */
10683 {
10689 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10691 {
10696 }
10698 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10700 {
10705 }
10706 }
10708 /* Optimize tan(x)*cos(x) as sin(x). */
10717 {
10723 }
10725 /* Optimize x*pow(x,c) as pow(x,c+1). */
10729 {
10735 {
10737 REAL_VALUE_TYPE c;
10738 tree arg;
10744 }
10745 }
10747 /* Optimize pow(x,c)*x as pow(x,c+1). */
10751 {
10757 {
10759 REAL_VALUE_TYPE c;
10760 tree arg;
10766 }
10767 }
10769 /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x. */
10771 && optimize
10773 {
10777 {
10780 }
10781 }
10782 }
10783 }
10787 bit_ior:
10788 /* ~X | X is -1. */
10791 {
10795 }
10797 /* X | ~X is -1. */
10800 {
10804 }
10806 /* Canonicalize (X & C1) | C2. */
10810 {
10815 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10823 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10828 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10829 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10830 mode which allows further optimizations. */
10835 {
10839 {
10842 }
10843 }
10850 c3)),
10851 arg1);
10852 }
10854 /* (X & ~Y) | (~X & Y) is X ^ Y */
10857 {
10874 }
10880 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10882 This results in more efficient code for machines without a NAND
10883 instruction. Combine will canonicalize to the first form
10884 which will allow use of NAND instructions provided by the
10885 backend if they exist. */
10888 {
10889 return
10896 }
10898 /* See if this can be simplified into a rotate first. If that
10899 is unsuccessful continue in the association code. */
10903 /* ~X ^ X is -1. */
10906 {
10910 }
10912 /* X ^ ~X is -1. */
10915 {
10919 }
10921 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10922 with a constant, and the two constants have no bits in common,
10923 we should treat this as a BIT_IOR_EXPR since this may produce more
10924 simplifications. */
10931 {
10934 }
10936 /* (X | Y) ^ X -> Y & ~ X*/
10939 {
10942 arg1);
10947 }
10949 /* (Y | X) ^ X -> Y & ~ X*/
10952 {
10955 arg1);
10960 }
10962 /* X ^ (X | Y) -> Y & ~ X*/
10965 {
10968 arg0);
10973 }
10975 /* X ^ (Y | X) -> Y & ~ X*/
10978 {
10981 arg0);
10986 }
10988 /* Convert ~X ^ ~Y to X ^ Y. */
10997 /* Convert ~X ^ C to X ^ ~C. */
11005 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11013 /* Fold (X & Y) ^ Y as ~X & Y. */
11016 {
11021 }
11022 /* Fold (X & Y) ^ X as ~Y & X. */
11026 {
11031 }
11032 /* Fold X ^ (X & Y) as X & ~Y. */
11035 {
11040 }
11041 /* Fold X ^ (Y & X) as ~Y & X. */
11045 {
11050 }
11052 /* See if this can be simplified into a rotate first. If that
11053 is unsuccessful continue in the association code. */
11057 /* ~X & X, (X == 0) & X, and !X & X are always zero. */
11065 /* X & ~X , X & (X == 0), and X & !X are always zero. */
11073 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11078 {
11079 tree tem2;
11086 }
11087 /* Fold ~X & 1 as (X & 1) == 0. */
11091 {
11092 tree tem2;
11099 }
11100 /* Fold !X & 1 as X == 0. */
11103 {
11107 }
11109 /* Fold (X ^ Y) & Y as ~X & Y. */
11112 {
11117 }
11118 /* Fold (X ^ Y) & X as ~Y & X. */
11122 {
11127 }
11128 /* Fold X & (X ^ Y) as X & ~Y. */
11131 {
11136 }
11137 /* Fold X & (Y ^ X) as ~Y & X. */
11141 {
11146 }
11148 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11149 multiple of 1 << CST. */
11151 {
11158 }
11160 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11161 bits from CST2. */
11165 {
11173 {
11174 /* Avoid the transform if arg1 is a mask of some
11175 mode which allows further optimizations. */
11182 }
11183 }
11185 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
11186 ((A & N) + B) & M -> (A + B) & M
11187 Similarly if (N & M) == 0,
11188 ((A | N) + B) & M -> (A + B) & M
11189 and for - instead of + (or unary - instead of +)
11190 and/or ^ instead of |.
11191 If B is constant and (B & M) == 0, fold into A & M. */
11193 {
11202 {
11205 wide_int cst0;
11207 /* Now we know that arg0 is (C + D) or (C - D) or
11208 -C and arg1 (M) is == (1LL << cst) - 1.
11209 Store C into PMOP[0] and D into PMOP[1]. */
11213 {
11216 }
11223 {
11233 {
11236 }
11239 /* If C or D is of the form (A & N) where
11240 (N & M) == M, or of the form (A | N) or
11241 (A ^ N) where (N & M) == 0, replace it with A. */
11245 /* If C or D is a N where (N & M) == 0, it can be
11246 omitted (assumed 0). */
11254 }
11256 /* Only build anything new if we optimized one or both arguments
11257 above. */
11261 {
11264 {
11265 /* Perform the operations in a type that has defined
11266 overflow behavior. */
11272 }
11277 {
11285 else
11287 }
11290 else
11293 /* TEM is now the new binary +, - or unary - replacement. */
11297 }
11298 }
11299 }
11304 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11307 {
11312 return
11314 }
11316 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
11318 This results in more efficient code for machines without a NOR
11319 instruction. Combine will canonicalize to the first form
11320 which will allow use of NOR instructions provided by the
11321 backend if they exist. */
11324 {
11331 }
11333 /* If arg0 is derived from the address of an object or function, we may
11334 be able to fold this expression using the object or function's
11335 alignment. */
11337 {
11344 /* This works because modulus is a power of 2. If this weren't the
11345 case, we'd have to replace it by its greatest power-of-2
11346 divisor: modulus & -modulus. */
11349 }
11351 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
11352 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
11353 if the new mask might be further optimized. */
11362 {
11373 {
11376 /* See if more bits can be proven as zero because of
11377 zero extension. */
11380 {
11385 {
11387 /* See if we can shorten the right shift. */
11390 /* Otherwise X >> C1 is all zeros, so we'll optimize
11391 it into (X, 0) later on by making sure zerobits
11392 is all ones. */
11393 }
11394 }
11397 {
11400 }
11401 /* For arithmetic shift if sign bit could be set, zerobits
11402 can contain actually sign bits, so no transformation is
11403 possible, unless MASK masks them all away. In that
11404 case the shift needs to be converted into logical shift. */
11407 {
11410 else
11412 }
11413 }
11415 /* ((X << 16) & 0xff00) is (X, 0). */
11422 {
11423 /* Only do the transformation if NEWMASK is some integer
11424 mode's mask. */
11431 {
11432 tree newmaskt;
11435 {
11441 }
11442 else
11447 }
11448 }
11449 }
11454 /* Don't touch a floating-point divide by zero unless the mode
11455 of the constant can represent infinity. */
11461 /* (-A) / (-B) -> A / B */
11471 /* Convert A/B/C to A/(B*C). */
11478 /* Convert A/(B/C) to (A/B)*C. */
11486 /* Convert C1/(X*C2) into (C1/C2)/X. */
11491 {
11497 }
11500 {
11504 /* Optimize sin(x)/cos(x) as tan(x). */
11510 {
11515 }
11517 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11523 {
11527 {
11532 }
11533 }
11535 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11536 NaNs or Infinities. */
11540 {
11547 {
11552 }
11553 }
11555 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11556 NaNs or Infinities. */
11560 {
11567 {
11571 {
11575 tmp);
11576 }
11577 }
11578 }
11580 /* Optimize pow(x,c)/x as pow(x,c-1). */
11584 {
11590 {
11592 REAL_VALUE_TYPE c;
11593 tree arg;
11599 }
11600 }
11602 /* Optimize a/root(b/c) into a*root(c/b). */
11604 {
11608 {
11617 }
11618 }
11620 /* Optimize x/expN(y) into x*expN(-y). */
11622 {
11629 }
11631 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11635 {
11643 }
11644 }
11648 /* Optimize (X & (-A)) / A where A is a power of 2,
11649 to X >> log2(A) */
11653 {
11661 }
11662 }
11664 /* Fall through */
11667 /* Simplify A / (B << N) where A and B are positive and B is
11668 a power of 2, to A >> (N + log2(B)). */
11673 {
11676 {
11684 WARN_STRICT_OVERFLOW_MISC);
11690 }
11691 }
11693 /* Fall through */
11701 /* Convert -A / -B to A / B when the type is signed and overflow is
11702 undefined. */
11706 {
11709 "when distributing negation across "
11711 WARN_STRICT_OVERFLOW_MISC);
11717 }
11721 {
11724 "when distributing negation across "
11726 WARN_STRICT_OVERFLOW_MISC);
11732 }
11734 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11735 operation, EXACT_DIV_EXPR.
11737 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11738 At one time others generated faster code, it's not clear if they do
11739 after the last round to changes to the DIV code in expmed.c. */
11748 {
11752 WARN_STRICT_OVERFLOW_MISC);
11754 }
11762 /* X % -Y is the same as X % Y. */
11775 {
11779 WARN_STRICT_OVERFLOW_MISC);
11781 }
11783 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11784 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11788 {
11790 /* Also optimize A % (C << N) where C is a power of 2,
11791 to A & ((C << N) - 1). */
11796 {
11797 tree mask
11802 "occur when simplifying "
11804 WARN_STRICT_OVERFLOW_MISC);
11808 }
11809 }
11817 /* Since negative shift count is not well-defined,
11818 don't try to compute it in the compiler. */
11824 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
11829 {
11833 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
11834 being well defined. */
11836 {
11842 else
11844 }
11848 }
11850 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
11851 into x & ((unsigned)-1 >> c) for unsigned types. */
11859 {
11862 tree lshift;
11863 tree arg00;
11866 {
11873 }
11874 }
11876 /* If we have a rotate of a bit operation with the rotate count and
11877 the second operand of the bit operation both constant,
11878 permute the two operations. */
11890 /* Two consecutive rotates adding up to the some integer
11891 multiple of the precision of the type can be ignored. */
11899 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
11900 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
11901 if the latter can be further optimized. */
11906 {
11910 arg1);
11914 arg1);
11918 }
11935 /* Note that the operands of this must be ints
11936 and their values must be 0 or 1.
11937 ("true" is a fixed value perhaps depending on the language.) */
11938 /* If first arg is constant zero, return it. */
11942 /* If either arg is constant true, drop it. */
11946 /* Preserve sequence points. */
11949 /* If second arg is constant zero, result is zero, but first arg
11950 must be evaluated. */
11953 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11954 case will be handled here. */
11958 /* !X && X is always false. */
11962 /* X && !X is always false. */
11967 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11968 means A >= Y && A != MAX, but in this case we know that
11969 A < X <= MAX. */
11973 {
11981 }
11990 /* Note that the operands of this must be ints
11991 and their values must be 0 or true.
11992 ("true" is a fixed value perhaps depending on the language.) */
11993 /* If first arg is constant true, return it. */
11997 /* If either arg is constant zero, drop it. */
12001 /* Preserve sequence points. */
12004 /* If second arg is constant true, result is true, but we must
12005 evaluate first arg. */
12008 /* Likewise for first arg, but note this only occurs here for
12009 TRUTH_OR_EXPR. */
12013 /* !X || X is always true. */
12017 /* X || !X is always true. */
12022 /* (X && !Y) || (!X && Y) is X ^ Y */
12025 {
12042 }
12051 /* If the second arg is constant zero, drop it. */
12054 /* If the second arg is constant true, this is a logical inversion. */
12056 {
12059 }
12060 /* Identical arguments cancel to zero. */
12064 /* !X ^ X is always true. */
12069 /* X ^ !X is always true. */
12085 /* bool_var != 0 becomes bool_var. */
12090 /* bool_var == 1 becomes bool_var. */
12095 /* bool_var != 1 becomes !bool_var. */
12102 /* bool_var == 0 becomes !bool_var. */
12109 /* !exp != 0 becomes !exp */
12114 /* If this is an equality comparison of the address of two non-weak,
12115 unaliased symbols neither of which are extern (since we do not
12116 have access to attributes for externs), then we know the result. */
12129 {
12130 /* We know that we're looking at the address of two
12131 non-weak, unaliased, static _DECL nodes.
12133 It is both wasteful and incorrect to call operand_equal_p
12134 to compare the two ADDR_EXPR nodes. It is wasteful in that
12135 all we need to do is test pointer equality for the arguments
12136 to the two ADDR_EXPR nodes. It is incorrect to use
12137 operand_equal_p as that function is NOT equivalent to a
12138 C equality test. It can in fact return false for two
12139 objects which would test as equal using the C equality
12140 operator. */
12144 type);
12145 }
12147 /* Similarly for a NEGATE_EXPR. */
12151 arg1)))
12156 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
12164 arg1),
12167 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
12176 {
12180 val,
12184 }
12186 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
12193 {
12195 code == NE_EXPR
12198 }
12200 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
12205 /* If this is an EQ or NE comparison with zero and ARG0 is
12206 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12207 two operations, but the latter can be done in one less insn
12208 on machines that have only two-operand insns or on which a
12209 constant cannot be the first operand. */
12212 {
12217 {
12224 arg1);
12225 }
12228 {
12235 arg1);
12236 }
12237 }
12239 /* If this is an NE or EQ comparison of zero against the result of a
12240 signed MOD operation whose second operand is a power of 2, make
12241 the MOD operation unsigned since it is simpler and equivalent. */
12249 {
12259 }
12261 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12262 C1 is a valid shift constant, and C2 is a power of two, i.e.
12263 a single bit. */
12267 == INTEGER_CST
12270 {
12275 /* Check for a valid shift count. */
12277 {
12281 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12282 can be rewritten as (X & (C2 << C1)) != 0. */
12284 {
12289 }
12290 /* Otherwise, for signed (arithmetic) shifts,
12291 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12292 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12296 /* Otherwise, of unsigned (logical) shifts,
12297 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12298 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12299 else
12303 arg000);
12304 }
12305 }
12307 /* If we have (A & C) == C where C is a power of 2, convert this into
12308 (A & C) != 0. Similarly for NE_EXPR. */
12314 integer_zero_node));
12316 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12317 bit, then fold the expression into A < 0 or A >= 0. */
12322 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12323 Similarly for NE_EXPR. */
12327 {
12331 tree dandnotc
12334 notc);
12338 }
12340 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12341 Similarly for NE_EXPR. */
12345 {
12347 tree candnotd
12354 }
12356 /* If this is a comparison of a field, we may be able to simplify it. */
12359 /* Handle the constant case even without -O
12360 to make sure the warnings are given. */
12362 {
12366 }
12368 /* Optimize comparisons of strlen vs zero to a compare of the
12369 first character of the string vs zero. To wit,
12370 strlen(ptr) == 0 => *ptr == 0
12371 strlen(ptr) != 0 => *ptr != 0
12372 Other cases should reduce to one of these two (or a constant)
12373 due to the return value of strlen being unsigned. */
12376 {
12384 {
12389 }
12390 }
12392 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12393 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12397 {
12402 {
12404 {
12407 }
12410 }
12411 }
12413 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12419 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12424 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12431 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12439 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12440 (X & C) == 0 when C is a single bit. */
12445 {
12452 arg1));
12453 }
12455 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12456 constant C is a power of two, i.e. a single bit. */
12463 {
12467 }
12469 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12470 when is C is a power of two, i.e. a single bit. */
12477 {
12483 }
12487 {
12490 }
12492 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12500 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12503 {
12516 arg01),
12525 arg01),
12534 arg00),
12543 arg00),
12545 }
12549 {
12556 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12557 operand_equal_p guarantees no side-effects so we don't need
12558 to use omit_one_operand on Z. */
12562 arg10));
12566 arg11));
12570 arg10));
12574 arg11));
12576 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12579 {
12585 }
12586 }
12588 /* Attempt to simplify equality/inequality comparisons of complex
12589 values. Only lower the comparison if the result is known or
12590 can be simplified to a single scalar comparison. */
12595 {
12600 {
12603 }
12604 else
12605 {
12608 }
12611 {
12614 }
12615 else
12616 {
12619 }
12623 {
12625 {
12630 }
12631 else
12632 {
12637 }
12638 }
12642 {
12644 {
12649 }
12650 else
12651 {
12656 }
12657 }
12658 }
12670 /* Transform comparisons of the form X +- C CMP X. */
12677 {
12684 else
12687 /* (X - c) > X becomes false. */
12691 {
12695 "occur when assuming that (X - c) > X "
12697 WARN_STRICT_OVERFLOW_ALL);
12699 }
12701 /* Likewise (X + c) < X becomes false. */
12705 {
12709 "occur when assuming that "
12711 WARN_STRICT_OVERFLOW_ALL);
12713 }
12715 /* Convert (X - c) <= X to true. */
12720 {
12724 "occur when assuming that "
12726 WARN_STRICT_OVERFLOW_ALL);
12728 }
12730 /* Convert (X + c) >= X to true. */
12735 {
12739 "occur when assuming that "
12741 WARN_STRICT_OVERFLOW_ALL);
12743 }
12746 {
12747 /* Convert X + c > X and X - c < X to true for integers. */
12751 {
12754 "not occur when assuming that "
12756 WARN_STRICT_OVERFLOW_ALL);
12758 }
12763 {
12766 "not occur when assuming that "
12768 WARN_STRICT_OVERFLOW_ALL);
12770 }
12772 /* Convert X + c <= X and X - c >= X to false for integers. */
12776 {
12779 "not occur when assuming that "
12781 WARN_STRICT_OVERFLOW_ALL);
12783 }
12788 {
12791 "not occur when assuming that "
12793 WARN_STRICT_OVERFLOW_ALL);
12795 }
12796 }
12797 }
12799 /* Comparisons with the highest or lowest possible integer of
12800 the specified precision will have known values. */
12801 {
12807 {
12814 {
12827 /* The GE_EXPR and LT_EXPR cases above are not normally
12828 reached because of previous transformations. */
12832 }
12835 {
12842 arg1);
12848 arg0),
12849 arg1);
12852 }
12855 {
12870 }
12873 {
12880 arg1);
12886 arg0),
12887 arg1);
12890 }
12894 /* We will flip the signedness of the comparison operator
12895 associated with the mode of arg1, so the sign bit is
12896 specified by this mode. Check that arg1 is the signed
12897 max associated with this sign bit. */
12899 /* signed_type does not work on pointer types. */
12901 {
12902 /* The following case also applies to X < signed_max+1
12903 and X >= signed_max+1 because previous transformations. */
12905 {
12911 }
12912 }
12913 }
12914 }
12916 /* If we are comparing an ABS_EXPR with a constant, we can
12917 convert all the cases into explicit comparisons, but they may
12918 well not be faster than doing the ABS and one comparison.
12919 But ABS (X) <= C is a range comparison, which becomes a subtraction
12920 and a comparison, and is probably faster. */
12934 /* Convert ABS_EXPR<x> >= 0 to true. */
12941 {
12944 "when simplifying comparison of "
12946 WARN_STRICT_OVERFLOW_CONDITIONAL);
12949 arg0);
12950 }
12952 /* Convert ABS_EXPR<x> < 0 to false. */
12957 {
12960 "when simplifying comparison of "
12962 WARN_STRICT_OVERFLOW_CONDITIONAL);
12965 arg0);
12966 }
12968 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12969 and similarly for >= into !=. */
12979 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12980 otherwise Y might be >= # of bits in X's type and thus e.g.
12981 (unsigned char) (1 << Y) for Y 15 might be 0.
12982 If the cast is widening, then 1 << Y should have unsigned type,
12983 otherwise if Y is number of bits in the signed shift type minus 1,
12984 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12985 31 might be 0xffffffff80000000. */
12996 {
13002 }
13015 {
13019 }
13021 /* If the first operand is NaN, the result is constant. */
13025 {
13027 ? integer_zero_node
13030 }
13032 /* If the second operand is NaN, the result is constant. */
13036 {
13038 ? integer_zero_node
13041 }
13043 /* Simplify unordered comparison of something with itself. */
13049 && !flag_trapping_math
13053 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
13054 {
13066 }
13071 /* When pedantic, a compound expression can be neither an lvalue
13072 nor an integer constant expression. */
13075 /* Don't let (0, 0) be null pointer constant. */
13089 /* An ASSERT_EXPR should never be passed to fold_binary. */
13094 {
13109 {
13115 }
13118 }
13124 {
13149 {
13162 }
13165 }
13170 }
13172 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
13173 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
13174 of GOTO_EXPR. */
13176 static tree
13178 {
13180 {
13187 /* ... fall through ... */
13191 }
13192 }
13194 /* Return whether the sub-tree ST contains a label which is accessible from
13195 outside the sub-tree. */
13197 static bool
13199 {
13200 return
13202 }
13204 /* Fold a ternary expression of code CODE and type TYPE with operands
13205 OP0, OP1, and OP2. Return the folded expression if folding is
13206 successful. Otherwise, return NULL_TREE. */
13208 tree
13211 {
13212 tree tem;
13219 /* If this is a commutative operation, and OP0 is a constant, move it
13220 to OP1 to reduce the number of tests below. */
13229 /* Strip any conversions that don't change the mode. This is safe
13230 for every expression, except for a comparison expression because
13231 its signedness is derived from its operands. So, in the latter
13232 case, only strip conversions that don't change the signedness.
13234 Note that this is done as an internal manipulation within the
13235 constant folder, in order to find the simplest representation of
13236 the arguments so that their form can be studied. In any cases,
13237 the appropriate type conversions should be put back in the tree
13238 that will get out of the constant folder. */
13240 {
13243 }
13246 {
13249 }
13252 {
13255 }
13258 {
13262 {
13268 }
13273 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
13274 so all simple results must be passed through pedantic_non_lvalue. */
13276 {
13279 /* Only optimize constant conditions when the selected branch
13280 has the same type as the COND_EXPR. This avoids optimizing
13281 away "c ? x : throw", where the throw has a void type.
13282 Avoid throwing away that operand which contains label. */
13289 }
13291 {
13296 {
13301 {
13309 }
13313 }
13314 }
13316 /* If we have A op B ? A : C, we may be able to convert this to a
13317 simpler expression, depending on the operation and the values
13318 of B and C. Signed zeros prevent all of these transformations,
13319 for reasons given above each one.
13321 Also try swapping the arguments and inverting the conditional. */
13326 {
13330 }
13334 op2,
13337 {
13341 {
13345 }
13346 }
13348 /* If the second operand is simpler than the third, swap them
13349 since that produces better jump optimization results. */
13352 {
13354 /* See if this can be inverted. If it can't, possibly because
13355 it was a floating-point inequality comparison, don't do
13356 anything. */
13360 }
13362 /* Convert A ? 1 : 0 to simply A. */
13367 /* If we try to convert OP0 to our type, the
13368 call to fold will try to move the conversion inside
13369 a COND, which will recurse. In that case, the COND_EXPR
13370 is probably the best choice, so leave it alone. */
13374 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13375 over COND_EXPR in cases such as floating point comparisons. */
13384 arg0)));
13386 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13391 {
13392 /* sign_bit_p looks through both zero and sign extensions,
13393 but for this optimization only sign extensions are
13394 usable. */
13397 {
13400 {
13403 }
13405 }
13406 /* sign_bit_p only checks ARG1 bits within A's precision.
13407 If <sign bit of A> has wider type than A, bits outside
13408 of A's precision in <sign bit of A> need to be checked.
13409 If they are all 0, this optimization needs to be done
13410 in unsigned A's type, if they are all 1 in signed A's type,
13411 otherwise this can't be done. */
13417 {
13419 tree tem_type;
13432 {
13435 }
13437 {
13440 }
13441 else
13443 }
13446 return
13452 arg1)));
13453 }
13455 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13456 already handled above. */
13461 {
13470 }
13472 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13473 is probably obsolete because the first operand should be a
13474 truth value (that's why we have the two cases above), but let's
13475 leave it in until we can confirm this for all front-ends. */
13487 /* Disable the transformations below for vectors, since
13488 fold_binary_op_with_conditional_arg may undo them immediately,
13489 yielding an infinite loop. */
13493 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13502 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13507 {
13509 /* Only perform transformation if ARG0 is easily inverted. */
13513 ? BIT_IOR_EXPR
13516 arg1);
13517 }
13519 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13524 {
13526 /* Only perform transformation if ARG0 is easily inverted. */
13532 op2);
13533 }
13535 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13547 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13548 of fold_ternary on them. */
13558 {
13568 {
13573 {
13581 }
13583 /* Constructor elements can be subvectors. */
13586 {
13590 }
13592 /* We keep an exact subset of the constructor elements. */
13594 {
13600 {
13604 }
13612 CONSTRUCTOR_ELT
13615 }
13616 /* The bitfield references a single constructor element. */
13618 {
13623 else
13627 }
13628 }
13629 }
13631 /* A bit-field-ref that referenced the full argument can be stripped. */
13637 /* On constants we can use native encode/interpret to constant
13638 fold (nearly) all BIT_FIELD_REFs. */
13642 /* This limitation should not be necessary, we just need to
13643 round this up to mode size. */
13645 /* Need bit-shifting of the buffer to relax the following. */
13647 {
13652 /* ??? We cannot tell native_encode_expr to start at
13653 some random byte only. So limit us to a reasonable amount
13654 of work. */
13656 {
13661 {
13667 }
13668 }
13669 }
13674 /* For integers we can decompose the FMA if possible. */
13686 {
13702 {
13707 /* Make sure that the perm value is in an acceptable
13708 range. */
13717 else
13722 }
13725 {
13730 }
13735 {
13740 }
13746 {
13750 }
13755 /* Some targets are deficient and fail to expand a single
13756 argument permutation while still allowing an equivalent
13757 2-argument version. */
13761 {
13764 }
13767 {
13774 }
13778 }
13784 }
13786 /* Perform constant folding and related simplification of EXPR.
13787 The related simplifications include x*1 => x, x*0 => 0, etc.,
13788 and application of the associative law.
13789 NOP_EXPR conversions may be removed freely (as long as we
13790 are careful not to change the type of the overall expression).
13791 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13792 but we can constant-fold them if they have constant operands. */
13794 #ifdef ENABLE_FOLD_CHECKING
13795 # define fold(x) fold_1 (x)
13797 static
13798 #endif
13799 tree
13801 {
13805 tree tem;
13808 /* Return right away if a constant. */
13812 /* CALL_EXPR-like objects with variable numbers of operands are
13813 treated specially. */
13815 {
13817 {
13820 }
13822 }
13825 {
13830 {
13848 }
13849 }
13852 {
13854 {
13861 {
13866 /* Find a matching index by means of a binary search. */
13868 {
13884 else
13886 }
13887 }
13890 }
13892 /* Return a VECTOR_CST if possible. */
13894 {
13901 tree value;
13904 {
13908 {
13911 }
13912 else
13914 }
13919 }
13927 }
13929 #ifdef ENABLE_FOLD_CHECKING
13930 #undef fold
13937 /* When --enable-checking=fold, compute a digest of expr before
13938 and after actual fold call to see if fold did not accidentally
13939 change original expr. */
13941 tree
13943 {
13944 tree ret;
13964 }
13966 void
13968 {
13979 }
13981 static void
13983 {
13985 }
13987 static void
13990 {
13996 recursive_label:
14006 {
14007 /* Allow DECL_ASSEMBLER_NAME to be modified. */
14011 }
14018 {
14019 /* Allow these fields to be modified. */
14020 tree tmp;
14028 {
14031 }
14032 }
14043 {
14046 {
14061 }
14065 {
14078 }
14095 {
14101 }
14104 {
14106 {
14109 }
14111 }
14122 {
14125 }
14135 }
14136 }
14138 /* Helper function for outputting the checksum of a tree T. When
14139 debugging with gdb, you can "define mynext" to be "next" followed
14140 by "call debug_fold_checksum (op0)", then just trace down till the
14141 outputs differ. */
14143 DEBUG_FUNCTION void
14145 {
14160 }
14162 #endif
14164 /* Fold a unary tree expression with code CODE of type TYPE with an
14165 operand OP0. LOC is the location of the resulting expression.
14166 Return a folded expression if successful. Otherwise, return a tree
14167 expression with code CODE of type TYPE with an operand OP0. */
14169 tree
14172 {
14173 tree tem;
14174 #ifdef ENABLE_FOLD_CHECKING
14183 #endif
14189 #ifdef ENABLE_FOLD_CHECKING
14196 #endif
14198 }
14200 /* Fold a binary tree expression with code CODE of type TYPE with
14201 operands OP0 and OP1. LOC is the location of the resulting
14202 expression. Return a folded expression if successful. Otherwise,
14203 return a tree expression with code CODE of type TYPE with operands
14204 OP0 and OP1. */
14206 tree
14209 MEM_STAT_DECL)
14210 {
14211 tree tem;
14212 #ifdef ENABLE_FOLD_CHECKING
14229 #endif
14235 #ifdef ENABLE_FOLD_CHECKING
14250 #endif
14252 }
14254 /* Fold a ternary tree expression with code CODE of type TYPE with
14255 operands OP0, OP1, and OP2. Return a folded expression if
14256 successful. Otherwise, return a tree expression with code CODE of
14257 type TYPE with operands OP0, OP1, and OP2. */
14259 tree
14262 {
14263 tree tem;
14264 #ifdef ENABLE_FOLD_CHECKING
14288 #endif
14295 #ifdef ENABLE_FOLD_CHECKING
14318 #endif
14320 }
14322 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
14323 arguments in ARGARRAY, and a null static chain.
14324 Return a folded expression if successful. Otherwise, return a CALL_EXPR
14325 of type TYPE from the given operands as constructed by build_call_array. */
14327 tree
14330 {
14331 tree tem;
14332 #ifdef ENABLE_FOLD_CHECKING
14351 #endif
14355 #ifdef ENABLE_FOLD_CHECKING
14371 #endif
14373 }
14375 /* Perform constant folding and related simplification of initializer
14376 expression EXPR. These behave identically to "fold_buildN" but ignore
14377 potential run-time traps and exceptions that fold must preserve. */
14379 #define START_FOLD_INIT \
14380 int saved_signaling_nans = flag_signaling_nans;\
14381 int saved_trapping_math = flag_trapping_math;\
14382 int saved_rounding_math = flag_rounding_math;\
14383 int saved_trapv = flag_trapv;\
14384 int saved_folding_initializer = folding_initializer;\
14385 flag_signaling_nans = 0;\
14386 flag_trapping_math = 0;\
14387 flag_rounding_math = 0;\
14388 flag_trapv = 0;\
14389 folding_initializer = 1;
14391 #define END_FOLD_INIT \
14392 flag_signaling_nans = saved_signaling_nans;\
14393 flag_trapping_math = saved_trapping_math;\
14394 flag_rounding_math = saved_rounding_math;\
14395 flag_trapv = saved_trapv;\
14396 folding_initializer = saved_folding_initializer;
14398 tree
14401 {
14402 tree result;
14403 START_FOLD_INIT;
14407 END_FOLD_INIT;
14409 }
14411 tree
14414 {
14415 tree result;
14416 START_FOLD_INIT;
14420 END_FOLD_INIT;
14422 }
14424 tree
14427 {
14428 tree result;
14429 START_FOLD_INIT;
14433 END_FOLD_INIT;
14435 }
14437 #undef START_FOLD_INIT
14438 #undef END_FOLD_INIT
14440 /* Determine if first argument is a multiple of second argument. Return 0 if
14441 it is not, or we cannot easily determined it to be.
14443 An example of the sort of thing we care about (at this point; this routine
14444 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14445 fold cases do now) is discovering that
14447 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14449 is a multiple of
14451 SAVE_EXPR (J * 8)
14453 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14455 This code also handles discovering that
14457 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14459 is a multiple of 8 so we don't have to worry about dealing with a
14460 possible remainder.
14462 Note that we *look* inside a SAVE_EXPR only to determine how it was
14463 calculated; it is not safe for fold to do much of anything else with the
14464 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14465 at run time. For example, the latter example above *cannot* be implemented
14466 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14467 evaluation time of the original SAVE_EXPR is not necessarily the same at
14468 the time the new expression is evaluated. The only optimization of this
14469 sort that would be valid is changing
14471 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14473 divided by 8 to
14475 SAVE_EXPR (I) * SAVE_EXPR (J)
14477 (where the same SAVE_EXPR (J) is used in the original and the
14478 transformed version). */
14480 int
14482 {
14490 {
14492 /* Bitwise and provides a power of two multiple. If the mask is
14493 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14496 /* FALLTHRU */
14509 {
14513 /* const_binop may not detect overflow correctly,
14514 so check for it explicitly here. */
14518 size_one_node,
14519 op1)))
14522 }
14526 /* Can't handle conversions from non-integral or wider integral type. */
14532 /* .. fall through ... */
14549 SIGNED);
14553 }
14554 }
14556 /* Return true if CODE or TYPE is known to be non-negative. */
14558 static bool
14560 {
14563 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14564 have a signed:1 type (where the value is -1 and 0). */
14567 }
14569 /* Return true if (CODE OP0) is known to be non-negative. If the return
14570 value is based on the assumption that signed overflow is undefined,
14571 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14572 *STRICT_OVERFLOW_P. */
14574 bool
14577 {
14582 {
14584 /* We can't return 1 if flag_wrapv is set because
14585 ABS_EXPR<INT_MIN> = INT_MIN. */
14589 {
14592 }
14599 strict_overflow_p);
14601 CASE_CONVERT:
14602 {
14607 {
14610 strict_overflow_p);
14612 {
14616 strict_overflow_p);
14617 }
14618 }
14620 {
14623 strict_overflow_p);
14627 }
14628 }
14633 }
14635 /* We don't know sign of `t', so be conservative and return false. */
14637 }
14639 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14640 value is based on the assumption that signed overflow is undefined,
14641 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14642 *STRICT_OVERFLOW_P. */
14644 bool
14647 {
14652 {
14657 strict_overflow_p)
14659 strict_overflow_p));
14661 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14662 both unsigned and at least 2 bits shorter than the result. */
14666 {
14671 {
14675 }
14676 }
14681 {
14682 /* x * x is always non-negative for floating point x
14683 or without overflow. */
14687 {
14691 }
14692 }
14694 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14695 both unsigned and their total bits is shorter than the result. */
14699 {
14718 {
14728 }
14729 }
14735 strict_overflow_p)
14737 strict_overflow_p));
14748 strict_overflow_p)
14750 strict_overflow_p));
14757 strict_overflow_p);
14760 }
14762 /* We don't know sign of `t', so be conservative and return false. */
14764 }
14766 /* Return true if T is known to be non-negative. If the return
14767 value is based on the assumption that signed overflow is undefined,
14768 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14769 *STRICT_OVERFLOW_P. */
14771 bool
14773 {
14778 {
14790 strict_overflow_p)
14792 strict_overflow_p));
14796 }
14797 /* We don't know sign of `t', so be conservative and return false. */
14799 }
14801 /* Return true if T is known to be non-negative. If the return
14802 value is based on the assumption that signed overflow is undefined,
14803 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14804 *STRICT_OVERFLOW_P. */
14806 bool
14809 {
14812 {
14832 /* Always true. */
14836 /* sqrt(-0.0) is -0.0. */
14840 strict_overflow_p);
14877 /* True if the 1st argument is nonnegative. */
14879 strict_overflow_p);
14882 /* True if the 1st OR 2nd arguments are nonnegative. */
14884 strict_overflow_p)
14886 strict_overflow_p)));
14889 /* True if the 1st AND 2nd arguments are nonnegative. */
14891 strict_overflow_p)
14893 strict_overflow_p)));
14896 /* True if the 2nd argument is nonnegative. */
14898 strict_overflow_p);
14901 /* True if the 1st argument is nonnegative or the second
14902 argument is an even integer. */
14907 strict_overflow_p);
14910 /* True if the 1st argument is nonnegative or the second
14911 argument is an even integer valued real. */
14913 {
14914 REAL_VALUE_TYPE c;
14915 HOST_WIDE_INT n;
14920 {
14921 REAL_VALUE_TYPE cint;
14925 }
14926 }
14928 strict_overflow_p);
14932 }
14934 type);
14935 }
14937 /* Return true if T is known to be non-negative. If the return
14938 value is based on the assumption that signed overflow is undefined,
14939 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14940 *STRICT_OVERFLOW_P. */
14942 static bool
14944 {
14950 {
14952 {
14956 /* If the initializer is non-void, then it's a normal expression
14957 that will be assigned to the slot. */
14961 /* Otherwise, the initializer sets the slot in some way. One common
14962 way is an assignment statement at the end of the initializer. */
14964 {
14972 else
14974 }
14978 strict_overflow_p);
14981 }
14984 {
14990 arg0,
14991 arg1,
14992 strict_overflow_p);
14993 }
14997 strict_overflow_p);
15000 strict_overflow_p);
15003 strict_overflow_p);
15008 }
15010 /* We don't know sign of `t', so be conservative and return false. */
15012 }
15014 /* Return true if T is known to be non-negative. If the return
15015 value is based on the assumption that signed overflow is undefined,
15016 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15017 *STRICT_OVERFLOW_P. */
15019 bool
15021 {
15028 {
15035 strict_overflow_p);
15041 strict_overflow_p);
15050 }
15053 {
15061 strict_overflow_p);
15066 strict_overflow_p);
15079 }
15080 }
15082 /* Return true if `t' is known to be non-negative. Handle warnings
15083 about undefined signed overflow. */
15085 bool
15087 {
15094 "determining that expression is always "
15096 WARN_STRICT_OVERFLOW_MISC);
15098 }
15101 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15102 For floating point we further ensure that T is not denormal.
15103 Similar logic is present in nonzero_address in rtlanal.h.
15105 If the return value is based on the assumption that signed overflow
15106 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15107 change *STRICT_OVERFLOW_P. */
15109 bool
15112 {
15114 {
15117 strict_overflow_p);
15120 {
15126 strict_overflow_p));
15127 }
15132 strict_overflow_p);
15136 }
15139 }
15141 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15142 For floating point we further ensure that T is not denormal.
15143 Similar logic is present in nonzero_address in rtlanal.h.
15145 If the return value is based on the assumption that signed overflow
15146 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15147 change *STRICT_OVERFLOW_P. */
15149 bool
15151 tree type,
15152 tree op0,
15154 {
15157 {
15161 {
15162 /* With the presence of negative values it is hard
15163 to say something. */
15170 /* One of operands must be positive and the other non-negative. */
15171 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15172 overflows, on a twos-complement machine the sum of two
15173 nonnegative numbers can never be zero. */
15175 strict_overflow_p)
15177 strict_overflow_p));
15178 }
15183 {
15185 strict_overflow_p)
15187 strict_overflow_p))
15188 {
15191 }
15192 }
15201 {
15204 }
15211 {
15215 /* When both operands are nonzero, then MAX must be too. */
15217 strict_overflow_p))
15220 /* MAX where operand 0 is positive is positive. */
15222 strict_overflow_p);
15223 }
15224 /* MAX where operand 1 is positive is positive. */
15229 {
15233 }
15238 strict_overflow_p)
15240 strict_overflow_p));
15244 }
15247 }
15249 /* Return true when T is an address and is known to be nonzero.
15250 For floating point we further ensure that T is not denormal.
15251 Similar logic is present in nonzero_address in rtlanal.h.
15253 If the return value is based on the assumption that signed overflow
15254 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15255 change *STRICT_OVERFLOW_P. */
15257 bool
15259 {
15262 {
15267 {
15276 /* For objects in symbol table check if we know they are non-zero.
15277 Don't do anything for variables and functions before symtab is built;
15278 it is quite possible that they will be declared weak later. */
15280 {
15286 else
15288 }
15290 /* Function local objects are never NULL. */
15297 /* Constants are never weak. */
15302 }
15310 {
15314 }
15319 }
15321 }
15323 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15324 attempt to fold the expression to a constant without modifying TYPE,
15325 OP0 or OP1.
15327 If the expression could be simplified to a constant, then return
15328 the constant. If the expression would not be simplified to a
15329 constant, then return NULL_TREE. */
15331 tree
15333 {
15336 }
15338 /* Given the components of a unary expression CODE, TYPE and OP0,
15339 attempt to fold the expression to a constant without modifying
15340 TYPE or OP0.
15342 If the expression could be simplified to a constant, then return
15343 the constant. If the expression would not be simplified to a
15344 constant, then return NULL_TREE. */
15346 tree
15348 {
15351 }
15353 /* If EXP represents referencing an element in a constant string
15354 (either via pointer arithmetic or array indexing), return the
15355 tree representing the value accessed, otherwise return NULL. */
15357 tree
15359 {
15363 {
15365 tree index;
15366 tree string;
15371 else
15372 {
15376 /* Optimize the special-case of a zero lower bound.
15378 We convert the low_bound to sizetype to avoid some problems
15379 with constant folding. (E.g. suppose the lower bound is 1,
15380 and its mode is QI. Without the conversion,l (ARRAY
15381 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15382 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15388 }
15401 }
15403 }
15405 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15406 an integer constant, real, or fixed-point constant.
15408 TYPE is the type of the result. */
15410 static tree
15412 {
15416 {
15418 {
15425 }
15432 {
15433 FIXED_VALUE_TYPE f;
15438 /* Propagate overflow flags. */
15442 }
15446 }
15449 }
15451 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15452 an integer constant or real constant.
15454 TYPE is the type of the result. */
15456 tree
15458 {
15462 {
15464 {
15465 /* If the value is unsigned or non-negative, then the absolute value
15466 is the same as the ordinary value. */
15470 /* If the value is negative, then the absolute value is
15471 its negation. */
15472 else
15473 {
15478 }
15479 }
15485 else
15491 }
15494 }
15496 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15497 constant. TYPE is the type of the result. */
15499 static tree
15501 {
15505 }
15507 /* Given CODE, a relational operator, the target type, TYPE and two
15508 constant operands OP0 and OP1, return the result of the
15509 relational operation. If the result is not a compile time
15510 constant, then return NULL_TREE. */
15512 static tree
15514 {
15517 /* From here on, the only cases we handle are when the result is
15518 known to be a constant. */
15521 {
15525 /* Handle the cases where either operand is a NaN. */
15527 {
15529 {
15557 }
15560 }
15563 }
15566 {
15570 }
15572 /* Handle equality/inequality of complex constants. */
15574 {
15585 else
15587 }
15590 {
15597 {
15609 }
15612 }
15614 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15616 To compute GT, swap the arguments and do LT.
15617 To compute GE, do LT and invert the result.
15618 To compute LE, swap the arguments, do LT and invert the result.
15619 To compute NE, do EQ and invert the result.
15621 Therefore, the code below must handle only EQ and LT. */
15624 {
15629 }
15631 /* Note that it is safe to invert for real values here because we
15632 have already handled the one case that it matters. */
15636 {
15639 }
15641 /* Compute a result for LT or EQ if args permit;
15642 Otherwise return T. */
15644 {
15647 else
15649 }
15650 else
15656 }
15658 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15659 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15660 itself. */
15662 tree
15664 {
15665 /* If the expression does not have side effects then we don't have to wrap
15666 it with a cleanup point expression. */
15670 /* If the expression is a return, check to see if the expression inside the
15671 return has no side effects or the right hand side of the modify expression
15672 inside the return. If either don't have side effects set we don't need to
15673 wrap the expression in a cleanup point expression. Note we don't check the
15674 left hand side of the modify because it should always be a return decl. */
15676 {
15683 }
15686 }
15688 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15689 of an indirection through OP0, or NULL_TREE if no simplification is
15690 possible. */
15692 tree
15694 {
15696 tree subtype;
15704 {
15707 /* *&CONST_DECL -> to the value of the const decl. */
15710 /* *&p => p; make sure to handle *&"str"[cst] here. */
15712 {
15716 else
15718 }
15719 /* *(foo *)&fooarray => fooarray[0] */
15722 && (!in_gimple_form
15724 {
15734 }
15735 /* *(foo *)&complexfoo => __real__ complexfoo */
15739 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15742 {
15746 }
15747 }
15751 {
15757 {
15758 tree op00type;
15762 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15765 {
15777 }
15778 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15781 {
15785 }
15786 /* ((foo *)&fooarray)[1] => fooarray[1] */
15789 {
15799 }
15800 }
15801 }
15803 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15806 && (!in_gimple_form
15808 {
15809 tree type_domain;
15819 NULL_TREE);
15820 }
15823 }
15825 /* Builds an expression for an indirection through T, simplifying some
15826 cases. */
15828 tree
15830 {
15838 }
15840 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15842 tree
15844 {
15849 else
15851 }
15853 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15854 whose result is ignored. The type of the returned tree need not be
15855 the same as the original expression. */
15857 tree
15859 {
15865 {
15876 else
15882 {
15898 }
15903 }
15904 }
15906 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
15908 tree
15910 {
15916 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15917 have to do anything. Only do this when we are not given a const,
15918 because in that case, this check is more expensive than just
15919 doing it. */
15921 {
15926 }
15928 /* If divisor is a power of two, simplify this to bit manipulation. */
15930 {
15932 {
15946 }
15947 else
15948 {
15949 tree t;
15955 }
15956 }
15957 else
15958 {
15963 }
15966 }
15968 /* Likewise, but round down. */
15970 tree
15972 {
15979 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15980 have to do anything. Only do this when we are not given a const,
15981 because in that case, this check is more expensive than just
15982 doing it. */
15984 {
15989 }
15991 /* If divisor is a power of two, simplify this to bit manipulation. */
15993 {
15994 tree t;
15998 }
15999 else
16000 {
16005 }
16008 }
16010 /* Returns the pointer to the base of the object addressed by EXP and
16011 extracts the information about the offset of the access, storing it
16012 to PBITPOS and POFFSET. */
16014 static tree
16017 {
16018 tree core;
16019 machine_mode mode;
16021 HOST_WIDE_INT bitsize;
16025 {
16030 }
16031 else
16032 {
16036 }
16039 }
16041 /* Returns true if addresses of E1 and E2 differ by a constant, false
16042 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16044 bool
16046 {
16060 {
16070 }
16072 {
16073 /* If only one of the offsets is non-constant, the difference cannot
16074 be a constant. */
16076 }
16077 else
16082 }
16084 /* Simplify the floating point expression EXP when the sign of the
16085 result is not significant. Return NULL_TREE if no simplification
16086 is possible. */
16088 tree
16090 {
16095 {
16131 {
16134 {
16136 /* Strip copysign function call, return the 1st argument. */
16142 /* Strip sign ops from the argument of "odd" math functions. */
16144 {
16148 }
16150 }
16151 }
16156 }
16158 }