| blob | ee9ed7b34fa8f5fa43faa20d0eb8c4eba8de345f |
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 *,
161 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
162 Otherwise, return LOC. */
164 static location_t
166 {
169 }
171 /* Similar to protected_set_expr_location, but never modify x in place,
172 if location can and needs to be set, unshare it. */
176 {
182 {
185 }
187 }
188 \f
189 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
190 division and returns the quotient. Otherwise returns
191 NULL_TREE. */
193 tree
195 {
196 widest_int quo;
203 }
204 \f
205 /* This is nonzero if we should defer warnings about undefined
206 overflow. This facility exists because these warnings are a
207 special case. The code to estimate loop iterations does not want
208 to issue any warnings, since it works with expressions which do not
209 occur in user code. Various bits of cleanup code call fold(), but
210 only use the result if it has certain characteristics (e.g., is a
211 constant); that code only wants to issue a warning if the result is
212 used. */
216 /* If a warning about undefined overflow is deferred, this is the
217 warning. Note that this may cause us to turn two warnings into
218 one, but that is fine since it is sufficient to only give one
219 warning per expression. */
223 /* If a warning about undefined overflow is deferred, this is the
224 level at which the warning should be emitted. */
228 /* Start deferring overflow warnings. We could use a stack here to
229 permit nested calls, but at present it is not necessary. */
231 void
233 {
235 }
237 /* Stop deferring overflow warnings. If there is a pending warning,
238 and ISSUE is true, then issue the warning if appropriate. STMT is
239 the statement with which the warning should be associated (used for
240 location information); STMT may be NULL. CODE is the level of the
241 warning--a warn_strict_overflow_code value. This function will use
242 the smaller of CODE and the deferred code when deciding whether to
243 issue the warning. CODE may be zero to mean to always use the
244 deferred code. */
246 void
248 {
250 location_t locus;
255 {
261 }
272 /* Use the smallest code level when deciding to issue the
273 warning. */
282 else
285 }
287 /* Stop deferring overflow warnings, ignoring any deferred
288 warnings. */
290 void
292 {
294 }
296 /* Whether we are deferring overflow warnings. */
298 bool
300 {
302 }
304 /* This is called when we fold something based on the fact that signed
305 overflow is undefined. */
307 static void
309 {
311 {
314 {
317 }
318 }
321 }
322 \f
323 /* Return true if the built-in mathematical function specified by CODE
324 is odd, i.e. -f(x) == f(-x). */
326 static bool
328 {
330 {
364 }
366 }
368 /* Check whether we may negate an integer constant T without causing
369 overflow. */
371 bool
373 {
374 tree type;
383 }
385 /* Determine whether an expression T can be cheaply negated using
386 the function negate_expr without introducing undefined overflow. */
388 static bool
390 {
391 tree type;
400 {
405 /* Check that -CST will not overflow type. */
416 /* We want to canonicalize to positive real constants. Pretend
417 that only negative ones can be easily negated. */
425 {
436 }
449 /* -(A + B) -> (-B) - A. */
454 /* -(A + B) -> (-A) - B. */
458 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
468 /* Fall through. */
479 /* In general we can't negate A / B, because if A is INT_MIN and
480 B is 1, we may turn this into INT_MIN / -1 which is undefined
481 and actually traps on some architectures. But if overflow is
482 undefined, we can negate, because - (INT_MIN / 1) is an
483 overflow. */
485 {
488 /* If overflow is undefined then we have to be careful because
489 we ask whether it's ok to associate the negate with the
490 division which is not ok for example for
491 -((a - b) / c) where (-(a - b)) / c may invoke undefined
492 overflow because of negating INT_MIN. So do not use
493 negate_expr_p here but open-code the two important cases. */
498 }
504 /* Negate -((double)float) as (double)(-float). */
506 {
510 }
514 /* Negate -f(x) as f(-x). */
520 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
522 {
526 }
531 }
533 }
535 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
536 simplification is possible.
537 If negate_expr_p would return true for T, NULL_TREE will never be
538 returned. */
540 static tree
542 {
544 tree tem;
547 {
548 /* Convert - (~A) to A + 1. */
564 /* Two's complement FP formats, such as c4x, may overflow. */
574 {
583 }
587 {
592 {
596 }
599 }
620 {
621 /* -(A + B) -> (-B) - A. */
625 {
629 }
631 /* -(A + B) -> (-A) - B. */
633 {
637 }
638 }
642 /* - (A - B) -> B - A */
654 /* Fall through. */
658 {
667 }
673 /* In general we can't negate A / B, because if A is INT_MIN and
674 B is 1, we may turn this into INT_MIN / -1 which is undefined
675 and actually traps on some architectures. But if overflow is
676 undefined, we can negate, because - (INT_MIN / 1) is an
677 overflow. */
679 {
684 {
691 }
692 /* If overflow is undefined then we have to be careful because
693 we ask whether it's ok to associate the negate with the
694 division which is not ok for example for
695 -((a - b) / c) where (-(a - b)) / c may invoke undefined
696 overflow because of negating INT_MIN. So do not use
697 negate_expr_p here but open-code the two important cases. */
706 }
710 /* Convert -((double)float) into (double)(-float). */
712 {
716 }
720 /* Negate -f(x) as f(-x). */
723 {
729 }
733 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
735 {
738 {
745 }
746 }
751 }
754 }
756 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
757 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
758 return NULL_TREE. */
760 static tree
762 {
764 location_t loc;
777 }
778 \f
779 /* Split a tree IN into a constant, literal and variable parts that could be
780 combined with CODE to make IN. "constant" means an expression with
781 TREE_CONSTANT but that isn't an actual constant. CODE must be a
782 commutative arithmetic operation. Store the constant part into *CONP,
783 the literal in *LITP and return the variable part. If a part isn't
784 present, set it to null. If the tree does not decompose in this way,
785 return the entire tree as the variable part and the other parts as null.
787 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
788 case, we negate an operand that was subtracted. Except if it is a
789 literal for which we use *MINUS_LITP instead.
791 If NEGATE_P is true, we are negating all of IN, again except a literal
792 for which we use *MINUS_LITP instead.
794 If IN is itself a literal or constant, return it as appropriate.
796 Note that we do not guarantee that any of the three values will be the
797 same type as IN, but they will have the same signedness and mode. */
799 static tree
802 {
809 /* Strip any conversions that don't change the machine mode or signedness. */
818 /* We can associate addition and subtraction together (even
819 though the C standard doesn't say so) for integers because
820 the value is not affected. For reals, the value might be
821 affected, so we can't. */
824 {
830 /* First see if either of the operands is a literal, then a constant. */
843 /* If we haven't dealt with either operand, this is not a case we can
844 decompose. Otherwise, VAR is either of the ones remaining, if any. */
849 else
852 /* Now do any needed negations. */
859 }
862 {
863 /* -X - 1 is folded to ~X, undo that here. */
866 }
869 else
873 {
880 }
883 }
885 /* Re-associate trees split by the above function. T1 and T2 are
886 either expressions to associate or null. Return the new
887 expression, if any. LOC is the location of the new expression. If
888 we build an operation, do it in TYPE and with CODE. */
890 static tree
892 {
898 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
899 try to fold this since we will have infinite recursion. But do
900 deal with any NEGATE_EXPRs. */
903 {
905 {
918 }
920 {
923 }
927 }
931 }
932 \f
933 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
934 for use in int_const_binop, size_binop and size_diffop. */
936 static bool
938 {
945 {
954 }
959 }
962 /* Combine two integer constants ARG1 and ARG2 under operation CODE
963 to produce a new constant. Return NULL_TREE if we don't know how
964 to evaluate CODE at compile-time. */
966 static tree
969 {
970 wide_int res;
971 tree t;
980 {
996 {
1000 else
1002 }
1005 /* It's unclear from the C standard whether shifts can overflow.
1006 The following code ignores overflow; perhaps a C standard
1007 interpretation ruling is needed. */
1009 else
1016 {
1020 else
1022 }
1026 else
1105 }
1113 }
1115 tree
1117 {
1119 }
1121 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1122 constant. We assume ARG1 and ARG2 have the same data type, or at least
1123 are the same kind of constant and the same machine mode. Return zero if
1124 combining the constants is not allowed in the current operating mode. */
1126 static tree
1128 {
1129 /* Sanity check for the recursive cases. */
1140 {
1141 machine_mode mode;
1142 REAL_VALUE_TYPE d1;
1143 REAL_VALUE_TYPE d2;
1144 REAL_VALUE_TYPE value;
1145 REAL_VALUE_TYPE result;
1149 /* The following codes are handled by real_arithmetic. */
1151 {
1162 }
1170 /* Don't perform operation if we honor signaling NaNs and
1171 either operand is a NaN. */
1176 /* Don't perform operation if it would raise a division
1177 by zero exception. */
1183 /* If either operand is a NaN, just return it. Otherwise, set up
1184 for floating-point trap; we return an overflow. */
1193 /* Don't constant fold this floating point operation if
1194 the result has overflowed and flag_trapping_math. */
1202 /* Don't constant fold this floating point operation if the
1203 result may dependent upon the run-time rounding mode and
1204 flag_rounding_math is set, or if GCC's software emulation
1205 is unable to accurately represent the result. */
1215 }
1218 {
1219 FIXED_VALUE_TYPE f1;
1220 FIXED_VALUE_TYPE f2;
1221 FIXED_VALUE_TYPE result;
1226 /* The following codes are handled by fixed_arithmetic. */
1228 {
1238 {
1243 }
1248 }
1255 /* Propagate overflow flags. */
1259 }
1262 {
1271 {
1282 mpc_mul);
1296 mpc_div);
1297 /* Fallthru ... */
1303 {
1304 /* Keep this algorithm in sync with
1305 tree-complex.c:expand_complex_div_straight().
1307 Expand complex division to scalars, straightforward algorithm.
1308 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1309 t = br*br + bi*bi
1310 */
1311 tree magsquared
1315 tree t1
1319 tree t2
1326 }
1327 else
1328 {
1329 /* Keep this algorithm in sync with
1330 tree-complex.c:expand_complex_div_wide().
1332 Expand complex division to scalars, modified algorithm to minimize
1333 overflow with wide input ranges. */
1339 {
1340 /* In the TRUE branch, we compute
1341 ratio = br/bi;
1342 div = (br * ratio) + bi;
1343 tr = (ar * ratio) + ai;
1344 ti = (ai * ratio) - ar;
1345 tr = tr / div;
1346 ti = ti / div; */
1357 }
1358 else
1359 {
1360 /* In the FALSE branch, we compute
1361 ratio = d/c;
1362 divisor = (d * ratio) + c;
1363 tr = (b * ratio) + a;
1364 ti = b - (a * ratio);
1365 tr = tr / div;
1366 ti = ti / div; */
1378 }
1379 }
1384 }
1388 }
1392 {
1398 {
1404 /* It is possible that const_binop cannot handle the given
1405 code and return NULL_TREE */
1408 }
1411 }
1413 /* Shifts allow a scalar offset for a vector. */
1416 {
1422 {
1427 /* It is possible that const_binop cannot handle the given
1428 code and return NULL_TREE. */
1431 }
1434 }
1436 }
1438 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1439 indicates which particular sizetype to create. */
1441 tree
1443 {
1445 }
1446 \f
1447 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1448 is a tree code. The type of the result is taken from the operands.
1449 Both must be equivalent integer types, ala int_binop_types_match_p.
1450 If the operands are constant, so is the result. */
1452 tree
1454 {
1463 /* Handle the special case of two integer constants faster. */
1465 {
1466 /* And some specific cases even faster than that. */
1468 {
1473 }
1475 {
1478 }
1480 {
1483 }
1485 /* Handle general case of two integer constants. For sizetype
1486 constant calculations we always want to know about overflow,
1487 even in the unsigned case. */
1489 }
1492 }
1494 /* Given two values, either both of sizetype or both of bitsizetype,
1495 compute the difference between the two values. Return the value
1496 in signed type corresponding to the type of the operands. */
1498 tree
1500 {
1502 tree ctype;
1507 /* If the type is already signed, just do the simple thing. */
1515 else
1518 /* If either operand is not a constant, do the conversions to the signed
1519 type and subtract. The hardware will do the right thing with any
1520 overflow in the subtraction. */
1526 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1527 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1528 overflow) and negate (which can't either). Special-case a result
1529 of zero while we're here. */
1535 else
1539 MINUS_EXPR,
1541 }
1542 \f
1543 /* A subroutine of fold_convert_const handling conversions of an
1544 INTEGER_CST to another integer type. */
1546 static tree
1548 {
1549 /* Given an integer constant, make new constant with new type,
1550 appropriately sign-extended or truncated. Use widest_int
1551 so that any extension is done according ARG1's type. */
1555 }
1557 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1558 to an integer type. */
1560 static tree
1562 {
1564 tree t;
1566 /* The following code implements the floating point to integer
1567 conversion rules required by the Java Language Specification,
1568 that IEEE NaNs are mapped to zero and values that overflow
1569 the target precision saturate, i.e. values greater than
1570 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1571 are mapped to INT_MIN. These semantics are allowed by the
1572 C and C++ standards that simply state that the behavior of
1573 FP-to-integer conversion is unspecified upon overflow. */
1575 wide_int val;
1576 REAL_VALUE_TYPE r;
1580 {
1587 }
1589 /* If R is NaN, return zero and show we have an overflow. */
1591 {
1594 }
1596 /* See if R is less than the lower bound or greater than the
1597 upper bound. */
1600 {
1604 {
1607 }
1608 }
1611 {
1614 {
1617 {
1620 }
1621 }
1622 }
1629 }
1631 /* A subroutine of fold_convert_const handling conversions of a
1632 FIXED_CST to an integer type. */
1634 static tree
1636 {
1637 tree t;
1641 /* Right shift FIXED_CST to temp by fbit. */
1645 {
1647 HOST_BITS_PER_DOUBLE_INT,
1650 /* Left shift temp to temp_trunc by fbit. */
1652 HOST_BITS_PER_DOUBLE_INT,
1654 }
1655 else
1656 {
1659 }
1661 /* If FIXED_CST is negative, we need to round the value toward 0.
1662 By checking if the fractional bits are not zero to add 1 to temp. */
1668 /* Given a fixed-point constant, make new constant with new type,
1669 appropriately sign-extended or truncated. */
1677 }
1679 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1680 to another floating point type. */
1682 static tree
1684 {
1685 REAL_VALUE_TYPE value;
1686 tree t;
1691 /* If converting an infinity or NAN to a representation that doesn't
1692 have one, set the overflow bit so that we can produce some kind of
1693 error message at the appropriate point if necessary. It's not the
1694 most user-friendly message, but it's better than nothing. */
1701 /* Regular overflow, conversion produced an infinity in a mode that
1702 can't represent them. */
1707 else
1710 }
1712 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1713 to a floating point type. */
1715 static tree
1717 {
1718 REAL_VALUE_TYPE value;
1719 tree t;
1726 }
1728 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1729 to another fixed-point type. */
1731 static tree
1733 {
1734 FIXED_VALUE_TYPE value;
1735 tree t;
1742 /* Propagate overflow flags. */
1746 }
1748 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
1749 to a fixed-point type. */
1751 static tree
1753 {
1754 FIXED_VALUE_TYPE value;
1755 tree t;
1757 double_int di;
1764 else
1772 /* Propagate overflow flags. */
1776 }
1778 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1779 to a fixed-point type. */
1781 static tree
1783 {
1784 FIXED_VALUE_TYPE value;
1785 tree t;
1793 /* Propagate overflow flags. */
1797 }
1799 /* Attempt to fold type conversion operation CODE of expression ARG1 to
1800 type TYPE. If no simplification can be done return NULL_TREE. */
1802 static tree
1804 {
1810 {
1817 }
1819 {
1826 }
1828 {
1835 }
1837 }
1839 /* Construct a vector of zero elements of vector type TYPE. */
1841 static tree
1843 {
1844 tree t;
1848 }
1850 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
1852 bool
1854 {
1869 {
1888 }
1889 }
1891 /* Convert expression ARG to type TYPE. Used by the middle-end for
1892 simple conversions in preference to calling the front-end's convert. */
1894 tree
1896 {
1898 tree tem;
1909 {
1912 /* Handle conversions between pointers to different address spaces. */
1917 /* fall through */
1922 {
1926 }
1940 {
1944 }
1946 {
1950 }
1952 {
1956 }
1959 {
1977 }
1982 {
1986 }
1989 {
2003 }
2007 {
2016 integer_zero_node));
2018 {
2022 {
2028 }
2036 }
2040 }
2058 }
2059 fold_convert_exit:
2062 }
2063 \f
2064 /* Return false if expr can be assumed not to be an lvalue, true
2065 otherwise. */
2067 static bool
2069 {
2070 /* We only need to wrap lvalue tree codes. */
2072 {
2103 /* Assume the worst for front-end tree codes. */
2107 }
2110 }
2112 /* Return an expr equal to X but certainly not valid as an lvalue. */
2114 tree
2116 {
2117 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2118 us. */
2125 }
2127 /* When pedantic, return an expr equal to X but certainly not valid as a
2128 pedantic lvalue. Otherwise, return X. */
2130 static tree
2132 {
2134 }
2135 \f
2136 /* Given a tree comparison code, return the code that is the logical inverse.
2137 It is generally not safe to do this for floating-point comparisons, except
2138 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2139 ERROR_MARK in this case. */
2141 enum tree_code
2143 {
2149 {
2180 }
2181 }
2183 /* Similar, but return the comparison that results if the operands are
2184 swapped. This is safe for floating-point. */
2186 enum tree_code
2188 {
2190 {
2216 }
2217 }
2220 /* Convert a comparison tree code from an enum tree_code representation
2221 into a compcode bit-based encoding. This function is the inverse of
2222 compcode_to_comparison. */
2224 static enum comparison_code
2226 {
2228 {
2259 }
2260 }
2262 /* Convert a compcode bit-based encoding of a comparison operator back
2263 to GCC's enum tree_code representation. This function is the
2264 inverse of comparison_to_compcode. */
2266 static enum tree_code
2268 {
2270 {
2301 }
2302 }
2304 /* Return a tree for the comparison which is the combination of
2305 doing the AND or OR (depending on CODE) of the two operations LCODE
2306 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2307 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2308 if this makes the transformation invalid. */
2310 tree
2315 {
2322 {
2333 }
2336 {
2337 /* Eliminate unordered comparisons, as well as LTGT and ORD
2338 which are not used unless the mode has NaNs. */
2344 }
2346 {
2347 /* Check that the original operation and the optimized ones will trap
2348 under the same condition. */
2359 /* In a short-circuited boolean expression the LHS might be
2360 such that the RHS, if evaluated, will never trap. For
2361 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2362 if neither x nor y is NaN. (This is a mixed blessing: for
2363 example, the expression above will never trap, hence
2364 optimizing it to x < y would be invalid). */
2369 /* If the comparison was short-circuited, and only the RHS
2370 trapped, we may now generate a spurious trap. */
2375 /* If we changed the conditions that cause a trap, we lose. */
2378 }
2384 else
2385 {
2390 }
2391 }
2392 \f
2393 /* Return nonzero if two operands (typically of the same tree node)
2394 are necessarily equal. If either argument has side-effects this
2395 function returns zero. FLAGS modifies behavior as follows:
2397 If OEP_ONLY_CONST is set, only return nonzero for constants.
2398 This function tests whether the operands are indistinguishable;
2399 it does not test whether they are equal using C's == operation.
2400 The distinction is important for IEEE floating point, because
2401 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2402 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2404 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2405 even though it may hold multiple values during a function.
2406 This is because a GCC tree node guarantees that nothing else is
2407 executed between the evaluation of its "operands" (which may often
2408 be evaluated in arbitrary order). Hence if the operands themselves
2409 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2410 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2411 unset means assuming isochronic (or instantaneous) tree equivalence.
2412 Unless comparing arbitrary expression trees, such as from different
2413 statements, this flag can usually be left unset.
2415 If OEP_PURE_SAME is set, then pure functions with identical arguments
2416 are considered the same. It is used when the caller has other ways
2417 to ensure that global memory is unchanged in between. */
2419 int
2421 {
2422 /* If either is ERROR_MARK, they aren't equal. */
2428 /* Similar, if either does not have a type (like a released SSA name),
2429 they aren't equal. */
2433 /* Check equality of integer constants before bailing out due to
2434 precision differences. */
2438 /* If both types don't have the same signedness, then we can't consider
2439 them equal. We must check this before the STRIP_NOPS calls
2440 because they may change the signedness of the arguments. As pointers
2441 strictly don't have a signedness, require either two pointers or
2442 two non-pointers as well. */
2447 /* We cannot consider pointers to different address space equal. */
2453 /* If both types don't have the same precision, then it is not safe
2454 to strip NOPs. */
2462 /* In case both args are comparisons but with different comparison
2463 code, try to swap the comparison operands of one arg to produce
2464 a match and compare that variant. */
2468 {
2476 }
2479 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2483 /* This is needed for conversions and for COMPONENT_REF.
2484 Might as well play it safe and always test this. */
2490 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2491 We don't care about side effects in that case because the SAVE_EXPR
2492 takes care of that for us. In all other cases, two expressions are
2493 equal if they have no side effects. If we have two identical
2494 expressions with side effects that should be treated the same due
2495 to the only side effects being identical SAVE_EXPR's, that will
2496 be detected in the recursive calls below.
2497 If we are taking an invariant address of two identical objects
2498 they are necessarily equal as well. */
2505 /* Next handle constant cases, those for which we can return 1 even
2506 if ONLY_CONST is set. */
2509 {
2524 {
2525 /* If we do not distinguish between signed and unsigned zero,
2526 consider them equal. */
2529 }
2533 {
2540 {
2544 }
2546 }
2550 flags)
2552 flags));
2566 }
2571 /* Define macros to test an operand from arg0 and arg1 for equality and a
2572 variant that allows null and views null as being different from any
2573 non-null value. In the latter case, if either is null, the both
2574 must be; otherwise, do the normal comparison. */
2575 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2576 TREE_OPERAND (arg1, N), flags)
2578 #define OP_SAME_WITH_NULL(N) \
2579 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2580 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2583 {
2585 /* Two conversions are equal only if signedness and modes match. */
2587 {
2588 CASE_CONVERT:
2596 }
2606 /* For commutative ops, allow the other order. */
2614 /* If either of the pointer (or reference) expressions we are
2615 dereferencing contain a side effect, these cannot be equal,
2616 but their addresses can be. */
2623 {
2634 /* Require equal extra operands and then fall through to MEM_REF
2635 handling of the two common operands. */
2640 /* Fallthru. */
2643 /* Require equal access sizes, and similar pointer types.
2644 We can have incomplete types for array references of
2645 variable-sized arrays from the Fortran frontend
2646 though. Also verify the types are compatible. */
2653 && alias_ptr_types_compatible_p
2660 /* Operands 2 and 3 may be null.
2661 Compare the array index by value if it is constant first as we
2662 may have different types but same value here. */
2673 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
2674 may be NULL when we're called to compare MEM_EXPRs. */
2689 }
2693 {
2707 /* The multiplcation operands are commutative. */
2708 /* FALLTHRU */
2716 /* Otherwise take into account this is a commutative operation. */
2729 }
2733 {
2735 /* If the CALL_EXPRs call different functions, then they
2736 clearly can not be equal. */
2738 flags))
2741 {
2745 else
2749 }
2751 /* Now see if all the arguments are the same. */
2752 {
2763 /* If we get here and both argument lists are exhausted
2764 then the CALL_EXPRs are equal. */
2766 }
2769 }
2772 /* Consider __builtin_sqrt equal to sqrt. */
2780 }
2782 #undef OP_SAME
2783 #undef OP_SAME_WITH_NULL
2784 }
2785 \f
2786 /* Similar to operand_equal_p, but see if ARG0 might have been made by
2787 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
2789 When in doubt, return 0. */
2791 static int
2793 {
2805 /* Discard any conversions that don't change the modes of ARG0 and ARG1
2806 and see if the inner values are the same. This removes any
2807 signedness comparison, which doesn't matter here. */
2814 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
2815 actual comparison operand, ARG0.
2817 First throw away any conversions to wider types
2818 already present in the operands. */
2827 {
2830 /* Make sure shorter operand is extended the right way
2831 to match the longer operand. */
2837 }
2840 }
2841 \f
2842 /* See if ARG is an expression that is either a comparison or is performing
2843 arithmetic on comparisons. The comparisons must only be comparing
2844 two different values, which will be stored in *CVAL1 and *CVAL2; if
2845 they are nonzero it means that some operands have already been found.
2846 No variables may be used anywhere else in the expression except in the
2847 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
2848 the expression and save_expr needs to be called with CVAL1 and CVAL2.
2850 If this is true, return 1. Otherwise, return zero. */
2852 static int
2854 {
2858 /* We can handle some of the tcc_expression cases here. */
2868 {
2869 /* If we've already found a CVAL1 or CVAL2, this expression is
2870 two complex to handle. */
2876 }
2879 {
2902 /* First see if we can handle the first operand, then the second. For
2903 the second operand, we know *CVAL1 can't be zero. It must be that
2904 one side of the comparison is each of the values; test for the
2905 case where this isn't true by failing if the two operands
2906 are the same. */
2915 ;
2919 ;
2920 else
2924 ;
2928 ;
2929 else
2936 }
2937 }
2938 \f
2939 /* ARG is a tree that is known to contain just arithmetic operations and
2940 comparisons. Evaluate the operations in the tree substituting NEW0 for
2941 any occurrence of OLD0 as an operand of a comparison and likewise for
2942 NEW1 and OLD1. */
2944 static tree
2947 {
2952 /* We can handle some of the tcc_expression cases here. */
2960 {
2975 {
2994 }
2995 /* Fall through - ??? */
2998 {
3002 /* We need to check both for exact equality and tree equality. The
3003 former will be true if the operand has a side-effect. In that
3004 case, we know the operand occurred exactly once. */
3017 }
3021 }
3022 }
3023 \f
3024 /* Return a tree for the case when the result of an expression is RESULT
3025 converted to TYPE and OMITTED was previously an operand of the expression
3026 but is now not needed (e.g., we folded OMITTED * 0).
3028 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3029 the conversion of RESULT to TYPE. */
3031 tree
3033 {
3036 /* If the resulting operand is an empty statement, just return the omitted
3037 statement casted to void. */
3047 }
3049 /* Return a tree for the case when the result of an expression is RESULT
3050 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3051 of the expression but are now not needed.
3053 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3054 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3055 evaluated before OMITTED2. Otherwise, if neither has side effects,
3056 just do the conversion of RESULT to TYPE. */
3058 tree
3061 {
3070 }
3072 \f
3073 /* Return a simplified tree node for the truth-negation of ARG. This
3074 never alters ARG itself. We assume that ARG is an operation that
3075 returns a truth value (0 or 1).
3077 FIXME: one would think we would fold the result, but it causes
3078 problems with the dominator optimizer. */
3080 static tree
3082 {
3087 /* If this is a comparison, we can simply invert it, except for
3088 floating-point non-equality comparisons, in which case we just
3089 enclose a TRUTH_NOT_EXPR around what we have. */
3092 {
3095 && flag_trapping_math
3106 }
3109 {
3128 /* Here we can invert either operand. We invert the first operand
3129 unless the second operand is a TRUTH_NOT_EXPR in which case our
3130 result is the XOR of the first operand with the inside of the
3131 negation of the second operand. */
3136 else
3159 {
3166 /* A COND_EXPR may have a throw as one operand, which
3167 then has void type. Just leave void operands
3168 as they are. */
3174 }
3186 CASE_CONVERT:
3190 /* ... fall through ... */
3212 }
3213 }
3215 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3216 assume that ARG is an operation that returns a truth value (0 or 1
3217 for scalars, 0 or -1 for vectors). Return the folded expression if
3218 folding is successful. Otherwise, return NULL_TREE. */
3220 static tree
3222 {
3225 ? BIT_NOT_EXPR
3228 }
3230 /* Return a simplified tree node for the truth-negation of ARG. This
3231 never alters ARG itself. We assume that ARG is an operation that
3232 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3234 tree
3236 {
3242 ? BIT_NOT_EXPR
3245 }
3247 /* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
3248 operands are another bit-wise operation with a common input. If so,
3249 distribute the bit operations to save an operation and possibly two if
3250 constants are involved. For example, convert
3251 (A | B) & (A | C) into A | (B & C)
3252 Further simplification will occur if B and C are constants.
3254 If this optimization cannot be done, 0 will be returned. */
3256 static tree
3259 {
3260 tree common;
3270 {
3274 }
3276 {
3280 }
3282 {
3286 }
3288 {
3292 }
3293 else
3301 }
3303 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3304 with code CODE. This optimization is unsafe. */
3305 static tree
3308 {
3312 /* (A / C) +- (B / C) -> (A +- B) / C. */
3322 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3327 {
3339 }
3342 }
3343 \f
3344 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3345 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */
3347 static tree
3350 {
3354 {
3361 }
3375 }
3377 /* Optimize a bit-field compare.
3379 There are two cases: First is a compare against a constant and the
3380 second is a comparison of two items where the fields are at the same
3381 bit position relative to the start of a chunk (byte, halfword, word)
3382 large enough to contain it. In these cases we can avoid the shift
3383 implicit in bitfield extractions.
3385 For constants, we emit a compare of the shifted constant with the
3386 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3387 compared. For two fields at the same position, we do the ANDs with the
3388 similar mask and compare the result of the ANDs.
3390 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3391 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3392 are the left and right operands of the comparison, respectively.
3394 If the optimization described above can be done, we return the resulting
3395 tree. Otherwise we return zero. */
3397 static tree
3400 {
3403 tree unsigned_type;
3409 tree mask;
3410 tree offset;
3412 /* Get all the information about the extractions being done. If the bit size
3413 if the same as the size of the underlying object, we aren't doing an
3414 extraction at all and so can do nothing. We also don't want to
3415 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3416 then will no longer be able to replace it. */
3424 {
3425 /* If this is not a constant, we can only do something if bit positions,
3426 sizes, and signedness are the same. */
3434 }
3436 /* See if we can find a mode to refer to this field. We should be able to,
3437 but fail if we can't. */
3446 /* Set signed and unsigned types of the precision of this mode for the
3447 shifts below. */
3450 /* Compute the bit position and size for the new reference and our offset
3451 within it. If the new reference is the same size as the original, we
3452 won't optimize anything, so return zero. */
3462 /* Make the mask to be used against the extracted field. */
3469 /* If not comparing with constant, just rework the comparison
3470 and return. */
3474 unsigned_type,
3477 mask),
3480 unsigned_type,
3483 mask));
3485 /* Otherwise, we are handling the constant case. See if the constant is too
3486 big for the field. Warn and return a tree of for 0 (false) if so. We do
3487 this not only for its own sake, but to avoid having to test for this
3488 error case below. If we didn't, we might generate wrong code.
3490 For unsigned fields, the constant shifted right by the field length should
3491 be all zero. For signed fields, the high-order bits should agree with
3492 the sign bit. */
3495 {
3497 {
3501 }
3502 }
3503 else
3504 {
3507 {
3511 }
3512 }
3514 /* Single-bit compares should always be against zero. */
3516 {
3519 }
3521 /* Make a new bitfield reference, shift the constant over the
3522 appropriate number of bits and mask it with the computed mask
3523 (in case this was a signed field). If we changed it, make a new one. */
3530 mask);
3535 }
3536 \f
3537 /* Subroutine for fold_truth_andor_1: decode a field reference.
3539 If EXP is a comparison reference, we return the innermost reference.
3541 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3542 set to the starting bit number.
3544 If the innermost field can be completely contained in a mode-sized
3545 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3547 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3548 otherwise it is not changed.
3550 *PUNSIGNEDP is set to the signedness of the field.
3552 *PMASK is set to the mask used. This is either contained in a
3553 BIT_AND_EXPR or derived from the width of the field.
3555 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3557 Return 0 if this is not a component reference or is one that we can't
3558 do anything with. */
3560 static tree
3565 {
3569 tree unsigned_type;
3572 /* All the optimizations using this function assume integer fields.
3573 There are problems with FP fields since the type_for_size call
3574 below can fail for, e.g., XFmode. */
3578 /* We are interested in the bare arrangement of bits, so strip everything
3579 that doesn't affect the machine mode. However, record the type of the
3580 outermost expression if it may matter below. */
3587 {
3593 }
3602 /* If the number of bits in the reference is the same as the bitsize of
3603 the outer type, then the outer type gives the signedness. Otherwise
3604 (in case of a small bitfield) the signedness is unchanged. */
3608 /* Compute the mask to access the bitfield. */
3617 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
3625 }
3627 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
3628 bit positions and MASK is SIGNED. */
3630 static int
3632 {
3636 /* If this function returns true when the type of the mask is
3637 UNSIGNED, then there will be errors. In particular see
3638 gcc.c-torture/execute/990326-1.c. There does not appear to be
3639 any documentation paper trail as to why this is so. But the pre
3640 wide-int worked with that restriction and it has been preserved
3641 here. */
3646 }
3648 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
3649 represents the sign bit of EXP's type. If EXP represents a sign
3650 or zero extension, also test VAL against the unextended type.
3651 The return value is the (sub)expression whose sign bit is VAL,
3652 or NULL_TREE otherwise. */
3654 static tree
3656 {
3658 tree t;
3660 /* Tree EXP must have an integral type. */
3665 /* Tree VAL must be an integer constant. */
3674 /* Handle extension from a narrower type. */
3680 }
3682 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
3683 to be evaluated unconditionally. */
3685 static int
3687 {
3688 /* Strip any conversions that don't change the machine mode. */
3697 /* Don't regard global variables as simple. They may be
3698 allocated in ways unknown to the compiler (shared memory,
3699 #pragma weak, etc). */
3702 /* Weakrefs are not safe to be read, since they can be NULL.
3703 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
3704 have DECL_WEAK flag set. */
3706 /* Loading a static variable is unduly expensive, but global
3707 registers aren't expensive. */
3709 }
3711 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
3712 to be evaluated unconditionally.
3713 I addition to simple_operand_p, we assume that comparisons, conversions,
3714 and logic-not operations are simple, if their operands are simple, too. */
3716 static bool
3718 {
3738 }
3740 \f
3741 /* The following functions are subroutines to fold_range_test and allow it to
3742 try to change a logical combination of comparisons into a range test.
3744 For example, both
3745 X == 2 || X == 3 || X == 4 || X == 5
3746 and
3747 X >= 2 && X <= 5
3748 are converted to
3749 (unsigned) (X - 2) <= 3
3751 We describe each set of comparisons as being either inside or outside
3752 a range, using a variable named like IN_P, and then describe the
3753 range with a lower and upper bound. If one of the bounds is omitted,
3754 it represents either the highest or lowest value of the type.
3756 In the comments below, we represent a range by two numbers in brackets
3757 preceded by a "+" to designate being inside that range, or a "-" to
3758 designate being outside that range, so the condition can be inverted by
3759 flipping the prefix. An omitted bound is represented by a "-". For
3760 example, "- [-, 10]" means being outside the range starting at the lowest
3761 possible value and ending at 10, in other words, being greater than 10.
3762 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
3763 always false.
3765 We set up things so that the missing bounds are handled in a consistent
3766 manner so neither a missing bound nor "true" and "false" need to be
3767 handled using a special case. */
3769 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
3770 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
3771 and UPPER1_P are nonzero if the respective argument is an upper bound
3772 and zero for a lower. TYPE, if nonzero, is the type of the result; it
3773 must be specified for a comparison. ARG1 will be converted to ARG0's
3774 type if both are specified. */
3776 static tree
3779 {
3780 tree tem;
3784 /* If neither arg represents infinity, do the normal operation.
3785 Else, if not a comparison, return infinity. Else handle the special
3786 comparison rules. Note that most of the cases below won't occur, but
3787 are handled for consistency. */
3790 {
3795 }
3800 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
3801 for neither. In real maths, we cannot assume open ended ranges are
3802 the same. But, this is computer arithmetic, where numbers are finite.
3803 We can therefore make the transformation of any unbounded range with
3804 the value Z, Z being greater than any representable number. This permits
3805 us to treat unbounded ranges as equal. */
3809 {
3830 }
3833 }
3834 \f
3835 /* Helper routine for make_range. Perform one step for it, return
3836 new expression if the loop should continue or NULL_TREE if it should
3837 stop. */
3839 tree
3843 {
3849 {
3851 /* We can only do something if the range is testing for zero. */
3860 /* We can only do something if the range is testing for zero
3861 and if the second operand is an integer constant. Note that
3862 saying something is "in" the range we make is done by
3863 complementing IN_P since it will set in the initial case of
3864 being not equal to zero; "out" is leaving it alone. */
3871 {
3892 }
3894 /* If this is an unsigned comparison, we also know that EXP is
3895 greater than or equal to zero. We base the range tests we make
3896 on that fact, so we record it here so we can parse existing
3897 range tests. We test arg0_type since often the return type
3898 of, e.g. EQ_EXPR, is boolean. */
3900 {
3904 NULL_TREE))
3909 /* If the high bound is missing, but we have a nonzero low
3910 bound, reverse the range so it goes from zero to the low bound
3911 minus 1. */
3913 {
3918 }
3919 }
3927 /* If flag_wrapv and ARG0_TYPE is signed, make sure
3928 low and high are non-NULL, then normalize will DTRT. */
3931 {
3936 }
3938 /* (-x) IN [a,b] -> x in [-b, -a] */
3950 /* ~ X -> -X - 1 */
3959 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
3960 move a constant to the other side. */
3965 /* If EXP is signed, any overflow in the computation is undefined,
3966 so we don't worry about it so long as our computations on
3967 the bounds don't overflow. For unsigned, overflow is defined
3968 and this is exactly the right thing. */
3980 normalize:
3981 /* Check for an unsigned range which has wrapped around the maximum
3982 value thus making n_high < n_low, and normalize it. */
3984 {
3990 /* If the range is of the form +/- [ x+1, x ], we won't
3991 be able to normalize it. But then, it represents the
3992 whole range or the empty set, so make it
3993 +/- [ -, - ]. */
3997 else
3999 }
4000 else
4008 CASE_CONVERT:
4026 /* If we're converting arg0 from an unsigned type, to exp,
4027 a signed type, we will be doing the comparison as unsigned.
4028 The tests above have already verified that LOW and HIGH
4029 are both positive.
4031 So we have to ensure that we will handle large unsigned
4032 values the same way that the current signed bounds treat
4033 negative values. */
4036 {
4037 tree high_positive;
4038 tree equiv_type;
4039 /* For fixed-point modes, we need to pass the saturating flag
4040 as the 2nd parameter. */
4042 equiv_type
4045 else
4046 equiv_type
4049 /* A range without an upper bound is, naturally, unbounded.
4050 Since convert would have cropped a very large value, use
4051 the max value for the destination type. */
4052 high_positive
4059 high_positive),
4062 /* If the low bound is specified, "and" the range with the
4063 range for which the original unsigned value will be
4064 positive. */
4066 {
4069 integer_zero_node),
4070 high_positive))
4074 }
4075 else
4076 {
4077 /* Otherwise, "or" the range with the range of the input
4078 that will be interpreted as negative. */
4081 integer_zero_node),
4082 high_positive))
4086 }
4087 }
4096 }
4097 }
4099 /* Given EXP, a logical expression, set the range it is testing into
4100 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4101 actually being tested. *PLOW and *PHIGH will be made of the same
4102 type as the returned expression. If EXP is not a comparison, we
4103 will most likely not be returning a useful value and range. Set
4104 *STRICT_OVERFLOW_P to true if the return value is only valid
4105 because signed overflow is undefined; otherwise, do not change
4106 *STRICT_OVERFLOW_P. */
4108 tree
4111 {
4119 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4120 and see if we can refine the range. Some of the cases below may not
4121 happen, but it doesn't seem worth worrying about this. We "continue"
4122 the outer loop when we've changed something; otherwise we "break"
4123 the switch, which will "break" the while. */
4129 {
4135 {
4143 }
4152 }
4154 /* If EXP is a constant, we can evaluate whether this is true or false. */
4156 {
4163 }
4167 }
4168 \f
4169 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4170 type, TYPE, return an expression to test if EXP is in (or out of, depending
4171 on IN_P) the range. Return 0 if the test couldn't be created. */
4173 tree
4176 {
4179 #ifdef HAVE_canonicalize_funcptr_for_compare
4180 /* Disable this optimization for function pointer expressions
4181 on targets that require function pointer canonicalization. */
4186 #endif
4189 {
4195 }
4213 {
4215 {
4219 }
4221 }
4223 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4225 {
4229 {
4231 {
4234 etype
4236 else
4239 }
4242 }
4243 }
4245 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4246 This requires wrap-around arithmetics for the type of the expression.
4247 First make sure that arithmetics in this type is valid, then make sure
4248 that it wraps around. */
4254 {
4257 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4258 for the type in question, as we rely on this here. */
4268 else
4270 }
4280 {
4282 {
4287 }
4289 }
4297 }
4298 \f
4299 /* Return the predecessor of VAL in its type, handling the infinite case. */
4301 static tree
4303 {
4309 else
4312 }
4314 /* Return the successor of VAL in its type, handling the infinite case. */
4316 static tree
4318 {
4324 else
4327 }
4329 /* Given two ranges, see if we can merge them into one. Return 1 if we
4330 can, 0 if we can't. Set the output range into the specified parameters. */
4332 bool
4335 {
4339 tree tem;
4349 /* Make range 0 be the range that starts first, or ends last if they
4350 start at the same value. Swap them if it isn't. */
4353 || (lowequal
4356 {
4360 }
4362 /* Now flag two cases, whether the ranges are disjoint or whether the
4363 second range is totally subsumed in the first. Note that the tests
4364 below are simplified by the ones above. */
4370 /* We now have four cases, depending on whether we are including or
4371 excluding the two ranges. */
4373 {
4374 /* If they don't overlap, the result is false. If the second range
4375 is a subset it is the result. Otherwise, the range is from the start
4376 of the second to the end of the first. */
4381 else
4383 }
4386 {
4387 /* If they don't overlap, the result is the first range. If they are
4388 equal, the result is false. If the second range is a subset of the
4389 first, and the ranges begin at the same place, we go from just after
4390 the end of the second range to the end of the first. If the second
4391 range is not a subset of the first, or if it is a subset and both
4392 ranges end at the same place, the range starts at the start of the
4393 first range and ends just before the second range.
4394 Otherwise, we can't describe this as a single range. */
4400 {
4405 {
4406 /* We are in the weird situation where high0 > high1 but
4407 high1 has no successor. Punt. */
4409 }
4410 }
4412 {
4417 {
4418 /* low0 < low1 but low1 has no predecessor. Punt. */
4420 }
4421 }
4422 else
4424 }
4427 {
4428 /* If they don't overlap, the result is the second range. If the second
4429 is a subset of the first, the result is false. Otherwise,
4430 the range starts just after the first range and ends at the
4431 end of the second. */
4436 else
4437 {
4442 {
4443 /* high1 > high0 but high0 has no successor. Punt. */
4445 }
4446 }
4447 }
4449 else
4450 {
4451 /* The case where we are excluding both ranges. Here the complex case
4452 is if they don't overlap. In that case, the only time we have a
4453 range is if they are adjacent. If the second is a subset of the
4454 first, the result is the first. Otherwise, the range to exclude
4455 starts at the beginning of the first range and ends at the end of the
4456 second. */
4458 {
4463 else
4464 {
4465 /* Canonicalize - [min, x] into - [-, x]. */
4468 {
4473 /* FALLTHROUGH */
4486 }
4488 /* Canonicalize - [x, max] into - [x, -]. */
4491 {
4496 /* FALLTHROUGH */
4512 }
4514 /* The ranges might be also adjacent between the maximum and
4515 minimum values of the given type. For
4516 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4517 return + [x + 1, y - 1]. */
4519 {
4526 }
4527 else
4529 }
4530 }
4533 else
4535 }
4539 }
4540 \f
4542 /* Subroutine of fold, looking inside expressions of the form
4543 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4544 of the COND_EXPR. This function is being used also to optimize
4545 A op B ? C : A, by reversing the comparison first.
4547 Return a folded expression whose code is not a COND_EXPR
4548 anymore, or NULL_TREE if no folding opportunity is found. */
4550 static tree
4553 {
4558 tree tem;
4563 /* If we have A op 0 ? A : -A, consider applying the following
4564 transformations:
4566 A == 0? A : -A same as -A
4567 A != 0? A : -A same as A
4568 A >= 0? A : -A same as abs (A)
4569 A > 0? A : -A same as abs (A)
4570 A <= 0? A : -A same as -abs (A)
4571 A < 0? A : -A same as -abs (A)
4573 None of these transformations work for modes with signed
4574 zeros. If A is +/-0, the first two transformations will
4575 change the sign of the result (from +0 to -0, or vice
4576 versa). The last four will fix the sign of the result,
4577 even though the original expressions could be positive or
4578 negative, depending on the sign of A.
4580 Note that all these transformations are correct if A is
4581 NaN, since the two alternatives (A and -A) are also NaNs. */
4588 /* In the case that A is of the form X-Y, '-A' (arg2) may
4589 have already been folded to Y-X, check for that. */
4597 {
4611 /* Fall through. */
4633 }
4635 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
4636 A == 0 ? A : 0 is always 0 unless A is -0. Note that
4637 both transformations are correct when A is NaN: A != 0
4638 is then true, and A == 0 is false. */
4642 {
4647 }
4649 /* Try some transformations of A op B ? A : B.
4651 A == B? A : B same as B
4652 A != B? A : B same as A
4653 A >= B? A : B same as max (A, B)
4654 A > B? A : B same as max (B, A)
4655 A <= B? A : B same as min (A, B)
4656 A < B? A : B same as min (B, A)
4658 As above, these transformations don't work in the presence
4659 of signed zeros. For example, if A and B are zeros of
4660 opposite sign, the first two transformations will change
4661 the sign of the result. In the last four, the original
4662 expressions give different results for (A=+0, B=-0) and
4663 (A=-0, B=+0), but the transformed expressions do not.
4665 The first two transformations are correct if either A or B
4666 is a NaN. In the first transformation, the condition will
4667 be false, and B will indeed be chosen. In the case of the
4668 second transformation, the condition A != B will be true,
4669 and A will be chosen.
4671 The conversions to max() and min() are not correct if B is
4672 a number and A is not. The conditions in the original
4673 expressions will be false, so all four give B. The min()
4674 and max() versions would give a NaN instead. */
4677 /* Avoid these transformations if the COND_EXPR may be used
4678 as an lvalue in the C++ front-end. PR c++/19199. */
4679 && (in_gimple_form
4685 {
4690 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
4692 {
4696 }
4699 {
4708 /* In C++ a ?: expression can be an lvalue, so put the
4709 operand which will be used if they are equal first
4710 so that we can convert this back to the
4711 corresponding COND_EXPR. */
4713 {
4722 }
4729 {
4738 }
4753 }
4754 }
4756 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
4757 we might still be able to simplify this. For example,
4758 if C1 is one less or one more than C2, this might have started
4759 out as a MIN or MAX and been transformed by this function.
4760 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
4766 {
4770 /* We can replace A with C1 in this case. */
4775 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
4776 MIN_EXPR, to preserve the signedness of the comparison. */
4778 OEP_ONLY_CONST)
4782 OEP_ONLY_CONST))
4783 {
4786 arg2));
4789 }
4793 /* If C1 is C2 - 1, this is min(A, C2), with the same care
4794 as above. */
4796 OEP_ONLY_CONST)
4800 OEP_ONLY_CONST))
4801 {
4804 arg2));
4807 }
4811 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
4812 MAX_EXPR, to preserve the signedness of the comparison. */
4814 OEP_ONLY_CONST)
4818 OEP_ONLY_CONST))
4819 {
4822 arg2));
4824 }
4828 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
4830 OEP_ONLY_CONST)
4834 OEP_ONLY_CONST))
4835 {
4838 arg2));
4840 }
4846 }
4849 }
4852 \f
4853 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
4854 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
4855 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
4856 false) >= 2)
4857 #endif
4859 /* EXP is some logical combination of boolean tests. See if we can
4860 merge it into some range test. Return the new tree if so. */
4862 static tree
4865 {
4881 /* If this is an OR operation, invert both sides; we will invert
4882 again at the end. */
4886 /* If both expressions are the same, if we can merge the ranges, and we
4887 can build the range test, return it or it inverted. If one of the
4888 ranges is always true or always false, consider it to be the same
4889 expression as the other. */
4897 {
4901 }
4903 /* On machines where the branch cost is expensive, if this is a
4904 short-circuited branch and the underlying object on both sides
4905 is the same, make a non-short-circuit operation. */
4911 {
4912 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
4913 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
4914 which cases we can't do this. */
4922 {
4931 {
4934 WARN_STRICT_OVERFLOW_COMPARISON);
4938 }
4939 }
4940 }
4943 }
4944 \f
4945 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
4946 bit value. Arrange things so the extra bits will be set to zero if and
4947 only if C is signed-extended to its full width. If MASK is nonzero,
4948 it is an INTEGER_CST that should be AND'ed with the extra bits. */
4950 static tree
4952 {
4955 tree temp;
4960 /* We work by getting just the sign bit into the low-order bit, then
4961 into the high-order bit, then sign-extend. We then XOR that value
4962 with C. */
4965 /* We must use a signed type in order to get an arithmetic right shift.
4966 However, we must also avoid introducing accidental overflows, so that
4967 a subsequent call to integer_zerop will work. Hence we must
4968 do the type conversion here. At this point, the constant is either
4969 zero or one, and the conversion to a signed type can never overflow.
4970 We could get an overflow if this conversion is done anywhere else. */
4979 /* If necessary, convert the type back to match the type of C. */
4984 }
4985 \f
4986 /* For an expression that has the form
4987 (A && B) || ~B
4988 or
4989 (A || B) && ~B,
4990 we can drop one of the inner expressions and simplify to
4991 A || ~B
4992 or
4993 A && ~B
4994 LOC is the location of the resulting expression. OP is the inner
4995 logical operation; the left-hand side in the examples above, while CMPOP
4996 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
4997 removing a condition that guards another, as in
4998 (A != NULL && A->...) || A == NULL
4999 which we must not transform. If RHS_ONLY is true, only eliminate the
5000 right-most operand of the inner logical operation. */
5002 static tree
5005 {
5023 {
5026 {
5029 }
5030 }
5032 {
5035 {
5038 }
5039 }
5054 }
5056 /* Find ways of folding logical expressions of LHS and RHS:
5057 Try to merge two comparisons to the same innermost item.
5058 Look for range tests like "ch >= '0' && ch <= '9'".
5059 Look for combinations of simple terms on machines with expensive branches
5060 and evaluate the RHS unconditionally.
5062 For example, if we have p->a == 2 && p->b == 4 and we can make an
5063 object large enough to span both A and B, we can do this with a comparison
5064 against the object ANDed with the a mask.
5066 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5067 operations to do this with one comparison.
5069 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5070 function and the one above.
5072 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5073 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5075 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5076 two operands.
5078 We return the simplified tree or 0 if no optimization is possible. */
5080 static tree
5083 {
5084 /* If this is the "or" of two comparisons, we can do something if
5085 the comparisons are NE_EXPR. If this is the "and", we can do something
5086 if the comparisons are EQ_EXPR. I.e.,
5087 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5089 WANTED_CODE is this operation code. For single bit fields, we can
5090 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5091 comparison for one-bit fields. */
5111 /* Start by getting the comparison codes. Fail if anything is volatile.
5112 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5113 it were surrounded with a NE_EXPR. */
5122 {
5126 }
5129 {
5133 }
5144 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5147 {
5150 {
5155 }
5158 {
5164 }
5165 }
5170 /* If the RHS can be evaluated unconditionally and its operands are
5171 simple, it wins to evaluate the RHS unconditionally on machines
5172 with expensive branches. In this case, this isn't a comparison
5173 that can be merged. */
5180 {
5181 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5192 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5202 }
5204 /* See if the comparisons can be merged. Then get all the parameters for
5205 each side. */
5229 /* It must be true that the inner operation on the lhs of each
5230 comparison must be the same if we are to be able to do anything.
5231 Then see if we have constants. If not, the same must be true for
5232 the rhs's. */
5243 else
5246 /* If either comparison code is not correct for our logical operation,
5247 fail. However, we can convert a one-bit comparison against zero into
5248 the opposite comparison against that bit being set in the field. */
5252 {
5254 {
5255 /* Make the left operand unsigned, since we are only interested
5256 in the value of one bit. Otherwise we are doing the wrong
5257 thing below. */
5260 }
5261 else
5263 }
5265 /* This is analogous to the code for l_const above. */
5267 {
5269 {
5272 }
5273 else
5275 }
5277 /* See if we can find a mode that contains both fields being compared on
5278 the left. If we can't, fail. Otherwise, update all constants and masks
5279 to be relative to a field of that size. */
5284 volatilep);
5294 {
5297 }
5305 {
5312 {
5316 }
5317 }
5319 {
5326 {
5330 }
5331 }
5333 /* If the right sides are not constant, do the same for it. Also,
5334 disallow this optimization if a size or signedness mismatch occurs
5335 between the left and right sides. */
5337 {
5340 /* Make sure the two fields on the right
5341 correspond to the left without being swapped. */
5349 volatilep);
5359 {
5362 }
5371 /* Make a mask that corresponds to both fields being compared.
5372 Do this for both items being compared. If the operands are the
5373 same size and the bits being compared are in the same position
5374 then we can do this by masking both and comparing the masked
5375 results. */
5379 {
5391 }
5393 /* There is still another way we can do something: If both pairs of
5394 fields being compared are adjacent, we may be able to make a wider
5395 field containing them both.
5397 Note that we still must mask the lhs/rhs expressions. Furthermore,
5398 the mask must be shifted to account for the shift done by
5399 make_bit_field_ref. */
5404 {
5405 tree type;
5419 /* Convert to the smaller type before masking out unwanted bits. */
5422 {
5424 {
5428 }
5430 {
5434 }
5435 }
5444 }
5447 }
5449 /* Handle the case of comparisons with constants. If there is something in
5450 common between the masks, those bits of the constants must be the same.
5451 If not, the condition is always false. Test for this to avoid generating
5452 incorrect code below. */
5457 {
5459 {
5462 }
5463 else
5464 {
5467 }
5468 }
5470 /* Construct the expression we will return. First get the component
5471 reference we will make. Unless the mask is all ones the width of
5472 that field, perform the mask operation. Then compare with the
5473 merged constant. */
5483 }
5484 \f
5485 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5486 constant. */
5488 static tree
5491 {
5494 tree comp_const;
5495 tree minmax_const;
5497 tree inner;
5508 /* If something does not permit us to optimize, return the original tree. */
5516 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5517 and GT_EXPR, doing the rest with recursive calls using logical
5518 simplifications. */
5520 {
5522 {
5523 tree tem
5530 }
5533 return
5535 optimize_minmax_comparison
5537 optimize_minmax_comparison
5542 /* MAX (X, 0) == 0 -> X <= 0 */
5546 /* MAX (X, 0) == 5 -> X == 5 */
5550 /* MAX (X, 0) == -1 -> false */
5554 /* MIN (X, 0) == 0 -> X >= 0 */
5558 /* MIN (X, 0) == 5 -> false */
5561 else
5562 /* MIN (X, 0) == -1 -> X == -1 */
5567 /* MAX (X, 0) > 0 -> X > 0
5568 MAX (X, 0) > 5 -> X > 5 */
5572 /* MAX (X, 0) > -1 -> true */
5576 /* MIN (X, 0) > 0 -> false
5577 MIN (X, 0) > 5 -> false */
5580 else
5581 /* MIN (X, 0) > -1 -> X > -1 */
5586 }
5587 }
5588 \f
5589 /* T is an integer expression that is being multiplied, divided, or taken a
5590 modulus (CODE says which and what kind of divide or modulus) by a
5591 constant C. See if we can eliminate that operation by folding it with
5592 other operations already in T. WIDE_TYPE, if non-null, is a type that
5593 should be used for the computation if wider than our type.
5595 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5596 (X * 2) + (Y * 4). We must, however, be assured that either the original
5597 expression would not overflow or that overflow is undefined for the type
5598 in the language in question.
5600 If we return a non-null expression, it is an equivalent form of the
5601 original computation, but need not be in the original type.
5603 We set *STRICT_OVERFLOW_P to true if the return values depends on
5604 signed overflow being undefined. Otherwise we do not change
5605 *STRICT_OVERFLOW_P. */
5607 static tree
5610 {
5611 /* To avoid exponential search depth, refuse to allow recursion past
5612 three levels. Beyond that (1) it's highly unlikely that we'll find
5613 something interesting and (2) we've probably processed it before
5614 when we built the inner expression. */
5617 tree ret;
5622 depth++;
5624 depth--;
5627 }
5629 static tree
5632 {
5643 /* Don't deal with constants of zero here; they confuse the code below. */
5653 /* Note that we need not handle conditional operations here since fold
5654 already handles those cases. So just do arithmetic here. */
5656 {
5658 /* For a constant, we can always simplify if we are a multiply
5659 or (for divide and modulus) if it is a multiple of our constant. */
5667 /* If op0 is an expression ... */
5673 /* ... and has wrapping overflow, and its type is smaller
5674 than ctype, then we cannot pass through as widening. */
5678 /* ... or this is a truncation (t is narrower than op0),
5679 then we cannot pass through this narrowing. */
5682 /* ... or signedness changes for division or modulus,
5683 then we cannot pass through this conversion. */
5687 /* ... or has undefined overflow while the converted to
5688 type has not, we cannot do the operation in the inner type
5689 as that would introduce undefined overflow. */
5694 /* Pass the constant down and see if we can make a simplification. If
5695 we can, replace this expression with the inner simplification for
5696 possible later conversion to our or some other type. */
5701 code == MULT_EXPR
5703 strict_overflow_p))))
5708 /* If widening the type changes it from signed to unsigned, then we
5709 must avoid building ABS_EXPR itself as unsigned. */
5711 {
5715 {
5718 }
5720 }
5721 /* If the constant is negative, we cannot simplify this. */
5724 /* FALLTHROUGH */
5726 /* For division and modulus, type can't be unsigned, as e.g.
5727 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
5728 For signed types, even with wrapping overflow, this is fine. */
5737 /* If widening the type changes the signedness, then we can't perform
5738 this optimization as that changes the result. */
5742 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
5748 {
5755 }
5759 /* If the second operand is constant, this is a multiplication
5760 or floor division, by a power of two, so we can treat it that
5761 way unless the multiplier or divisor overflows. Signed
5762 left-shift overflow is implementation-defined rather than
5763 undefined in C90, so do not convert signed left shift into
5764 multiplication. */
5767 /* const_binop may not detect overflow correctly,
5768 so check for it explicitly here. */
5772 size_one_node,
5773 op1)))
5777 ctype,
5779 t1),
5784 /* See if we can eliminate the operation on both sides. If we can, we
5785 can return a new PLUS or MINUS. If we can't, the only remaining
5786 cases where we can do anything are if the second operand is a
5787 constant. */
5793 /* If not multiplication, we can only do this if both operands
5794 are divisible by c. */
5797 {
5802 }
5804 /* If this was a subtraction, negate OP1 and set it to be an addition.
5805 This simplifies the logic below. */
5807 {
5809 /* If OP1 was not easily negatable, the constant may be OP0. */
5811 {
5818 }
5819 }
5824 /* If either OP1 or C are negative, this optimization is not safe for
5825 some of the division and remainder types while for others we need
5826 to change the code. */
5828 {
5836 }
5838 /* If it's a multiply or a division/modulus operation of a multiple
5839 of our constant, do the operation and verify it doesn't overflow. */
5842 {
5845 /* We allow the constant to overflow with wrapping semantics. */
5849 }
5850 else
5853 /* If we have an unsigned type, we cannot widen the operation since it
5854 will change the result if the original computation overflowed. */
5858 /* If we were able to eliminate our operation from the first side,
5859 apply our operation to the second side and reform the PLUS. */
5863 /* The last case is if we are a multiply. In that case, we can
5864 apply the distributive law to commute the multiply and addition
5865 if the multiplication of the constants doesn't overflow
5866 and overflow is defined. With undefined overflow
5867 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
5873 op1);
5878 /* We have a special case here if we are doing something like
5879 (C * 8) % 4 since we know that's zero. */
5882 /* If the multiplication can overflow we cannot optimize this. */
5886 {
5889 }
5891 /* ... fall through ... */
5895 /* If we can extract our operation from the LHS, do so and return a
5896 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
5897 do something only if the second operand is a constant. */
5911 /* If these are the same operation types, we can associate them
5912 assuming no overflow. */
5914 {
5926 }
5928 /* If these operations "cancel" each other, we have the main
5929 optimizations of this pass, which occur when either constant is a
5930 multiple of the other, in which case we replace this with either an
5931 operation or CODE or TCODE.
5933 If we have an unsigned type, we cannot do this since it will change
5934 the result if the original computation overflowed. */
5941 {
5943 {
5950 }
5952 {
5959 }
5960 }
5965 }
5968 }
5969 \f
5970 /* Return a node which has the indicated constant VALUE (either 0 or
5971 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
5972 and is of the indicated TYPE. */
5974 tree
5976 {
5985 else
5987 }
5990 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
5991 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
5992 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
5993 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
5994 COND is the first argument to CODE; otherwise (as in the example
5995 given here), it is the second argument. TYPE is the type of the
5996 original expression. Return NULL_TREE if no simplification is
5997 possible. */
5999 static tree
6004 {
6014 {
6018 /* If this operand throws an expression, then it does not make
6019 sense to try to perform a logical or arithmetic operation
6020 involving it. */
6025 }
6026 else
6027 {
6032 }
6037 /* This transformation is only worthwhile if we don't have to wrap ARG
6038 in a SAVE_EXPR and the operation can be simplified without recursing
6039 on at least one of the branches once its pushed inside the COND_EXPR. */
6048 {
6052 else
6054 }
6056 {
6060 else
6062 }
6064 /* Check that we have simplified at least one of the branches. */
6069 }
6071 \f
6072 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6074 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6075 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6076 ADDEND is the same as X.
6078 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6079 and finite. The problematic cases are when X is zero, and its mode
6080 has signed zeros. In the case of rounding towards -infinity,
6081 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6082 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6084 bool
6086 {
6090 /* Don't allow the fold with -fsignaling-nans. */
6094 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6098 /* In a vector or complex, we would need to check the sign of all zeros. */
6102 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6106 /* The mode has signed zeros, and we have to honor their sign.
6107 In this situation, there is only one case we can return true for.
6108 X - 0 is the same as X unless rounding towards -infinity is
6109 supported. */
6111 }
6113 /* Subroutine of fold() that checks comparisons of built-in math
6114 functions against real constants.
6116 FCODE is the DECL_FUNCTION_CODE of the built-in, CODE is the comparison
6117 operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR, GE_EXPR or LE_EXPR. TYPE
6118 is the type of the result and ARG0 and ARG1 are the operands of the
6119 comparison. ARG1 must be a TREE_REAL_CST.
6121 The function returns the constant folded tree if a simplification
6122 can be made, and NULL_TREE otherwise. */
6124 static tree
6128 {
6129 REAL_VALUE_TYPE c;
6132 {
6138 {
6139 /* sqrt(x) < y is always false, if y is negative. */
6143 /* sqrt(x) > y is always true, if y is negative and we
6144 don't care about NaNs, i.e. negative values of x. */
6148 /* sqrt(x) > y is the same as x >= 0, if y is negative. */
6151 }
6153 {
6154 REAL_VALUE_TYPE c2;
6160 {
6161 /* sqrt(x) > y is x == +Inf, when y is very large. */
6166 /* sqrt(x) > y is always false, when y is very large
6167 and we don't care about infinities. */
6169 }
6171 /* sqrt(x) > c is the same as x > c*c. */
6174 }
6176 {
6177 REAL_VALUE_TYPE c2;
6183 {
6184 /* sqrt(x) < y is always true, when y is a very large
6185 value and we don't care about NaNs or Infinities. */
6189 /* sqrt(x) < y is x != +Inf when y is very large and we
6190 don't care about NaNs. */
6195 /* sqrt(x) < y is x >= 0 when y is very large and we
6196 don't care about Infinities. */
6201 /* sqrt(x) < y is x >= 0 && x != +Inf, when y is large. */
6206 dconst0)),
6209 c2)));
6210 }
6212 /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */
6217 /* sqrt(x) < c is the same as x >= 0 && x < c*c. */
6222 dconst0)),
6225 c2)));
6226 }
6227 }
6230 }
6232 /* Subroutine of fold() that optimizes comparisons against Infinities,
6233 either +Inf or -Inf.
6235 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6236 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6237 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6239 The function returns the constant folded tree if a simplification
6240 can be made, and NULL_TREE otherwise. */
6242 static tree
6245 {
6246 machine_mode mode;
6247 REAL_VALUE_TYPE max;
6248 tree temp;
6253 /* For negative infinity swap the sense of the comparison. */
6259 {
6261 /* x > +Inf is always false, if with ignore sNANs. */
6267 /* x <= +Inf is always true, if we don't case about NaNs. */
6271 /* x <= +Inf is the same as x == x, i.e. isfinite(x). */
6277 /* x == +Inf and x >= +Inf are always equal to x > DBL_MAX. */
6283 /* x < +Inf is always equal to x <= DBL_MAX. */
6289 /* x != +Inf is always equal to !(x > DBL_MAX). */
6301 }
6304 }
6306 /* Subroutine of fold() that optimizes comparisons of a division by
6307 a nonzero integer constant against an integer constant, i.e.
6308 X/C1 op C2.
6310 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6311 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6312 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6314 The function returns the constant folded tree if a simplification
6315 can be made, and NULL_TREE otherwise. */
6317 static tree
6320 {
6328 /* We have to do this the hard way to detect unsigned overflow.
6329 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6335 {
6340 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6344 }
6346 {
6350 {
6369 }
6370 }
6371 else
6372 {
6373 /* A negative divisor reverses the relational operators. */
6379 {
6398 }
6399 }
6402 {
6423 {
6426 }
6431 {
6434 }
6439 {
6442 }
6447 {
6450 }
6455 }
6458 }
6461 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6462 equality/inequality test, then return a simplified form of the test
6463 using a sign testing. Otherwise return NULL. TYPE is the desired
6464 result type. */
6466 static tree
6469 tree result_type)
6470 {
6471 /* If this is testing a single bit, we can optimize the test. */
6475 {
6476 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6477 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6481 /* This is only a win if casting to a signed type is cheap,
6482 i.e. when arg00's type is not a partial mode. */
6485 {
6488 result_type,
6491 }
6492 }
6495 }
6497 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6498 equality/inequality test, then return a simplified form of
6499 the test using shifts and logical operations. Otherwise return
6500 NULL. TYPE is the desired result type. */
6502 tree
6505 {
6506 /* If this is testing a single bit, we can optimize the test. */
6510 {
6519 /* First, see if we can fold the single bit test into a sign-bit
6520 test. */
6522 result_type);
6526 /* Otherwise we have (A & C) != 0 where C is a single bit,
6527 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6528 Similarly for (A & C) == 0. */
6530 /* If INNER is a right shift of a constant and it plus BITNUM does
6531 not overflow, adjust BITNUM and INNER. */
6537 {
6540 }
6542 /* If we are going to be able to omit the AND below, we must do our
6543 operations as unsigned. If we must use the AND, we have a choice.
6544 Normally unsigned is faster, but for some machines signed is. */
6545 #ifdef LOAD_EXTEND_OP
6548 #else
6550 #endif
6566 /* Put the AND last so it can combine with more things. */
6569 /* Make sure to return the proper type. */
6573 }
6575 }
6577 /* Check whether we are allowed to reorder operands arg0 and arg1,
6578 such that the evaluation of arg1 occurs before arg0. */
6580 static bool
6582 {
6589 }
6591 /* Test whether it is preferable two swap two operands, ARG0 and
6592 ARG1, for example because ARG0 is an integer constant and ARG1
6593 isn't. If REORDER is true, only recommend swapping if we can
6594 evaluate the operands in reverse order. */
6596 bool
6598 {
6616 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6617 for commutative and comparison operators. Ensuring a canonical
6618 form allows the optimizers to find additional redundancies without
6619 having to explicitly check for both orderings. */
6625 /* Put SSA_NAMEs last. */
6631 /* Put variables last. */
6638 }
6640 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where
6641 ARG0 is extended to a wider type. */
6643 static tree
6646 {
6648 tree arg1_unw;
6657 #ifdef HAVE_canonicalize_funcptr_for_compare
6658 /* Disable this optimization if we're casting a function pointer
6659 type on targets that require function pointer canonicalization. */
6664 #endif
6671 /* If possible, express the comparison in the shorter mode. */
6691 /* If we are comparing with the integer that does not fit into the range
6692 of the shorter type, the result is known. */
6703 {
6730 }
6733 }
6735 /* Fold comparison ARG0 CODE ARG1 (with result in TYPE), where for
6736 ARG0 just the signedness is changed. */
6738 static tree
6741 {
6742 tree arg0_inner;
6752 #ifdef HAVE_canonicalize_funcptr_for_compare
6753 /* Disable this optimization if we're casting a function pointer
6754 type on targets that require function pointer canonicalization. */
6759 #endif
6780 else
6784 }
6787 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6788 means A >= Y && A != MAX, but in this case we know that
6789 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6791 static tree
6793 {
6800 else
6809 {
6812 }
6814 {
6817 }
6818 else
6825 {
6826 /* Convert the pointer types into integer before taking the difference. */
6830 }
6831 else
6838 }
6840 /* Fold a sum or difference of at least one multiplication.
6841 Returns the folded tree or NULL if no simplification could be made. */
6843 static tree
6846 {
6850 /* (A * C) +- (B * C) -> (A+-B) * C.
6851 (A * C) +- A -> A * (C+-1).
6852 We are most concerned about the case where C is a constant,
6853 but other combinations show up during loop reduction. Since
6854 it is not difficult, try all four possibilities. */
6857 {
6860 }
6862 {
6865 }
6866 else
6867 {
6868 /* We cannot generate constant 1 for fract. */
6873 }
6875 {
6878 }
6880 {
6882 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6883 the purpose of this canonicalization. */
6887 {
6890 }
6891 else
6893 }
6894 else
6895 {
6896 /* We cannot generate constant 1 for fract. */
6901 }
6913 /* No identical multiplicands; see if we can find a common
6914 power-of-two factor in non-power-of-two multiplies. This
6915 can help in multi-dimensional array access. */
6918 {
6921 tree maybe_same;
6925 /* Move min of absolute values to int11. */
6927 {
6932 }
6933 else
6937 /* The remainder should not be a constant, otherwise we
6938 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6939 increased the number of multiplications necessary. */
6941 {
6949 }
6950 }
6960 }
6962 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6963 specified by EXPR into the buffer PTR of length LEN bytes.
6964 Return the number of bytes placed in the buffer, or zero
6965 upon failure. */
6967 static int
6969 {
6983 {
6985 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
6986 number of bytes. */
6990 {
6997 else
6999 }
7000 else
7005 }
7007 }
7010 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7011 specified by EXPR into the buffer PTR of length LEN bytes.
7012 Return the number of bytes placed in the buffer, or zero
7013 upon failure. */
7015 static int
7017 {
7021 FIXED_VALUE_TYPE value;
7037 }
7040 /* Subroutine of native_encode_expr. Encode the REAL_CST
7041 specified by EXPR into the buffer PTR of length LEN bytes.
7042 Return the number of bytes placed in the buffer, or zero
7043 upon failure. */
7045 static int
7047 {
7053 /* There are always 32 bits in each long, no matter the size of
7054 the hosts long. We handle floating point representations with
7055 up to 192 bits. */
7069 {
7074 {
7081 else
7083 }
7084 else
7090 }
7092 }
7094 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7095 specified by EXPR into the buffer PTR of length LEN bytes.
7096 Return the number of bytes placed in the buffer, or zero
7097 upon failure. */
7099 static int
7101 {
7103 tree part;
7118 }
7121 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7122 specified by EXPR into the buffer PTR of length LEN bytes.
7123 Return the number of bytes placed in the buffer, or zero
7124 upon failure. */
7126 static int
7128 {
7138 {
7140 {
7143 }
7154 }
7156 }
7159 /* Subroutine of native_encode_expr. Encode the STRING_CST
7160 specified by EXPR into the buffer PTR of length LEN bytes.
7161 Return the number of bytes placed in the buffer, or zero
7162 upon failure. */
7164 static int
7166 {
7168 HOST_WIDE_INT total_bytes;
7182 {
7185 {
7188 }
7191 }
7192 else
7195 }
7198 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7199 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7200 buffer PTR of length LEN bytes. If OFF is not -1 then start
7201 the encoding at byte offset OFF and encode at most LEN bytes.
7202 Return the number of bytes placed in the buffer, or zero upon failure. */
7204 int
7206 {
7208 {
7229 }
7230 }
7233 /* Subroutine of native_interpret_expr. Interpret the contents of
7234 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7235 If the buffer cannot be interpreted, return NULL_TREE. */
7237 static tree
7239 {
7249 }
7252 /* Subroutine of native_interpret_expr. Interpret the contents of
7253 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7254 If the buffer cannot be interpreted, return NULL_TREE. */
7256 static tree
7258 {
7260 double_int result;
7261 FIXED_VALUE_TYPE fixed_value;
7271 }
7274 /* Subroutine of native_interpret_expr. Interpret the contents of
7275 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7276 If the buffer cannot be interpreted, return NULL_TREE. */
7278 static tree
7280 {
7285 /* There are always 32 bits in each long, no matter the size of
7286 the hosts long. We handle floating point representations with
7287 up to 192 bits. */
7288 REAL_VALUE_TYPE r;
7299 {
7302 {
7309 else
7311 }
7312 else
7317 }
7321 }
7324 /* Subroutine of native_interpret_expr. Interpret the contents of
7325 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7326 If the buffer cannot be interpreted, return NULL_TREE. */
7328 static tree
7330 {
7345 }
7348 /* Subroutine of native_interpret_expr. Interpret the contents of
7349 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7350 If the buffer cannot be interpreted, return NULL_TREE. */
7352 static tree
7354 {
7367 {
7372 }
7374 }
7377 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7378 the buffer PTR of length LEN as a constant of type TYPE. For
7379 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7380 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7381 return NULL_TREE. */
7383 tree
7385 {
7387 {
7409 }
7410 }
7412 /* Returns true if we can interpret the contents of a native encoding
7413 as TYPE. */
7415 static bool
7417 {
7419 {
7432 }
7433 }
7435 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7436 TYPE at compile-time. If we're unable to perform the conversion
7437 return NULL_TREE. */
7439 static tree
7441 {
7442 /* We support up to 512-bit values (for V8DFmode). */
7446 /* Check that the host and target are sane. */
7455 }
7457 /* Build an expression for the address of T. Folds away INDIRECT_REF
7458 to avoid confusing the gimplify process. */
7460 tree
7462 {
7463 /* The size of the object is not relevant when talking about its address. */
7468 {
7473 }
7483 {
7488 }
7489 else
7493 }
7495 /* Build an expression for the address of T. */
7497 tree
7499 {
7503 }
7507 /* Fold a unary expression of code CODE and type TYPE with operand
7508 OP0. Return the folded expression if folding is successful.
7509 Otherwise, return NULL_TREE. */
7511 tree
7513 {
7514 tree tem;
7515 tree arg0;
7527 {
7530 {
7531 /* Don't use STRIP_NOPS, because signedness of argument type
7532 matters. */
7534 }
7535 else
7536 {
7537 /* Strip any conversions that don't change the mode. This
7538 is safe for every expression, except for a comparison
7539 expression because its signedness is derived from its
7540 operands.
7542 Note that this is done as an internal manipulation within
7543 the constant folder, in order to find the simplest
7544 representation of the arguments so that their form can be
7545 studied. In any cases, the appropriate type conversions
7546 should be put back in the tree that will get out of the
7547 constant folder. */
7549 }
7550 }
7553 {
7560 {
7574 /* If this was a conversion, and all we did was to move into
7575 inside the COND_EXPR, bring it back out. But leave it if
7576 it is a conversion from integer to integer and the
7577 result precision is no wider than a word since such a
7578 conversion is cheap and may be optimized away by combine,
7579 while it couldn't if it were outside the COND_EXPR. Then return
7580 so we don't get into an infinite recursion loop taking the
7581 conversion out and then back in. */
7593 && (INTEGRAL_TYPE_P
7606 }
7607 }
7610 {
7616 CASE_CONVERT:
7620 {
7621 /* If we have (type) (a CMP b) and type is an integral type, return
7622 new expression involving the new type. Canonicalize
7623 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7624 non-integral type.
7625 Do not fold the result as that would not simplify further, also
7626 folding again results in recursions. */
7636 }
7638 /* Handle (T *)&A.B.C for A being of type T and B and C
7639 living at offset zero. This occurs frequently in
7640 C++ upcasting and then accessing the base. */
7644 {
7646 tree offset;
7647 machine_mode mode;
7652 /* If the reference was to a (constant) zero offset, we can use
7653 the address of the base if it has the same base type
7654 as the result type and the pointer type is unqualified. */
7661 }
7665 /* Detect assigning a bitfield. */
7667 && DECL_BIT_FIELD
7669 {
7670 /* Don't leave an assignment inside a conversion
7671 unless assigning a bitfield. */
7673 /* First do the assignment, then return converted constant. */
7678 }
7680 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7681 constants (if x has signed type, the sign bit cannot be set
7682 in c). This folds extension into the BIT_AND_EXPR.
7683 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7684 very likely don't have maximal range for their precision and this
7685 transformation effectively doesn't preserve non-maximal ranges. */
7689 {
7700 <= HOST_BITS_PER_WIDE_INT
7702 {
7706 cst &= HOST_WIDE_INT_M1U
7709 #ifdef LOAD_EXTEND_OP
7711 && !flag_syntax_only
7714 {
7718 }
7719 #endif
7720 }
7722 {
7727 }
7728 }
7730 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type,
7731 when one of the new casts will fold away. Conservatively we assume
7732 that this happens when X or Y is NOP_EXPR or Y is INTEGER_CST. */
7739 {
7743 return fold_build_pointer_plus_loc
7745 }
7747 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7748 of the same precision, and X is an integer type not narrower than
7749 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7755 {
7761 }
7763 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7764 type of X and Y (integer types only). */
7769 {
7770 /* Be careful not to introduce new overflows. */
7771 tree mult_type;
7774 else
7778 {
7785 }
7786 }
7816 /* Convert fabs((double)float) into (double)fabsf(float). */
7819 {
7825 targ0));
7826 }
7827 /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on. */
7831 /* Strip sign ops from argument. */
7833 {
7838 }
7845 {
7851 }
7853 {
7858 }
7866 /* Convert ~ (-A) to A - 1. */
7871 /* Convert ~ (A - 1) or ~ (A + -1) to -A. */
7880 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7895 /* Perform BIT_NOT_EXPR on each element individually. */
7897 {
7899 tree elem;
7904 {
7910 }
7913 }
7918 /* Note that the operand of this must be an int
7919 and its values must be 0 or 1.
7920 ("true" is a fixed value perhaps depending on the language,
7921 but we don't handle values other than 1 correctly yet.) */
7933 {
7941 }
7943 {
7948 }
7950 {
7954 {
7963 }
7964 }
7973 {
7981 }
7983 {
7987 }
7989 {
7993 {
8002 }
8003 }
8007 /* Fold *&X to X if X is an lvalue. */
8009 {
8016 }
8023 {
8042 else
8046 {
8050 }
8053 }
8058 {
8072 {
8077 }
8080 {
8084 }
8087 }
8092 }
8095 /* If the operation was a conversion do _not_ mark a resulting constant
8096 with TREE_OVERFLOW if the original constant was not. These conversions
8097 have implementation defined behavior and retaining the TREE_OVERFLOW
8098 flag here would confuse later passes such as VRP. */
8099 tree
8102 {
8111 }
8113 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8114 operands OP0 and OP1. LOC is the location of the resulting expression.
8115 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8116 Return the folded expression if folding is successful. Otherwise,
8117 return NULL_TREE. */
8118 static tree
8121 {
8122 tree tem;
8124 /* We only do these simplifications if we are optimizing. */
8128 /* Check for things like (A || B) && (A || C). We can convert this
8129 to A || (B && C). Note that either operator can be any of the four
8130 truth and/or operations and the transformation will still be
8131 valid. Also note that we only care about order for the
8132 ANDIF and ORIF operators. If B contains side effects, this
8133 might change the truth-value of A. */
8140 {
8160 /* This case if tricky because we must either have commutative
8161 operators or else A10 must not have side-effects. */
8167 a01);
8168 }
8170 /* See if we can build a range comparison. */
8176 {
8180 }
8184 {
8188 }
8190 /* Check for the possibility of merging component references. If our
8191 lhs is another similar operation, try to merge its rhs with our
8192 rhs. Then try to merge our lhs and rhs. */
8206 {
8213 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8214 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8215 We don't want to pack more than two leafs to a non-IF AND/OR
8216 expression.
8217 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8218 equal to IF-CODE, then we don't want to add right-hand operand.
8219 If the inner right-hand side of left-hand operand has
8220 side-effects, or isn't simple, then we can't add to it,
8221 as otherwise we might destroy if-sequence. */
8224 /* Needed for sequence points to handle trappings, and
8225 side-effects. */
8227 {
8229 arg1);
8231 tem);
8232 }
8233 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8234 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8237 /* Needed for sequence points to handle trappings, and
8238 side-effects. */
8240 {
8245 }
8246 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8247 into (A OR B).
8248 For sequence point consistancy, we need to check for trapping,
8249 and side-effects. */
8253 }
8256 }
8258 /* Fold a binary expression of code CODE and type TYPE with operands
8259 OP0 and OP1, containing either a MIN-MAX or a MAX-MIN combination.
8260 Return the folded expression if folding is successful. Otherwise,
8261 return NULL_TREE. */
8263 static tree
8265 {
8272 else
8275 /* MIN (MAX (a, b), b) == b. */
8280 /* MIN (MAX (b, a), b) == b. */
8286 /* MIN (a, MAX (a, b)) == a. */
8292 /* MIN (a, MAX (b, a)) == a. */
8299 }
8301 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8302 by changing CODE to reduce the magnitude of constants involved in
8303 ARG0 of the comparison.
8304 Returns a canonicalized comparison tree if a simplification was
8305 possible, otherwise returns NULL_TREE.
8306 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8307 valid if signed overflow is undefined. */
8309 static tree
8313 {
8319 /* Match A +- CST code arg1 and CST code arg1. We can change the
8320 first form only if overflow is undefined. */
8322 /* In principle pointers also have undefined overflow behavior,
8323 but that causes problems elsewhere. */
8331 /* Identify the constant in arg0 and its sign. */
8334 else
8338 /* Overflowed constants and zero will cause problems. */
8343 /* See if we can reduce the magnitude of the constant in
8344 arg0 by changing the comparison code. */
8346 {
8347 /* CST <= arg1 -> CST-1 < arg1. */
8350 /* -CST < arg1 -> -CST-1 <= arg1. */
8353 /* CST > arg1 -> CST-1 >= arg1. */
8356 /* -CST >= arg1 -> -CST-1 > arg1. */
8359 else
8361 /* arg1 code' CST' might be more canonical. */
8363 }
8364 else
8365 {
8366 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8370 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8374 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8378 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8382 else
8385 }
8387 /* Now build the constant reduced in magnitude. But not if that
8388 would produce one outside of its types range. */
8396 /* We cannot swap the comparison here as that would cause us to
8397 endlessly recurse. */
8406 /* If swapping might yield to a more canonical form, do so. */
8409 else
8411 }
8413 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8414 overflow further. Try to decrease the magnitude of constants involved
8415 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8416 and put sole constants at the second argument position.
8417 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8419 static tree
8422 {
8423 tree t;
8428 /* Try canonicalization by simplifying arg0. */
8433 {
8437 }
8439 /* Try canonicalization by simplifying arg1 using the swapped
8440 comparison. */
8448 }
8450 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8451 space. This is used to avoid issuing overflow warnings for
8452 expressions like &p->x which can not wrap. */
8454 static bool
8456 {
8463 wide_int wi_offset;
8469 else
8485 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8486 array. */
8488 {
8489 HOST_WIDE_INT base_size;
8494 }
8497 }
8499 /* Return the HOST_WIDE_INT least significant bits of T, a sizetype
8500 kind INTEGER_CST. This makes sure to properly sign-extend the
8501 constant. */
8503 static HOST_WIDE_INT
8505 {
8511 }
8513 /* Subroutine of fold_binary. This routine performs all of the
8514 transformations that are common to the equality/inequality
8515 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8516 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8517 fold_binary should call fold_binary. Fold a comparison with
8518 tree code CODE and type TYPE with operands OP0 and OP1. Return
8519 the folded comparison or NULL_TREE. */
8521 static tree
8524 {
8534 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1. */
8541 {
8542 const enum tree_code
8549 /* If the constant operation overflowed this can be
8550 simplified as a comparison against INT_MAX/INT_MIN. */
8553 {
8557 /* Get the sign of the constant on the lhs if the
8558 operation were VARIABLE + CONST1. */
8562 /* The sign of the constant determines if we overflowed
8563 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8564 Canonicalize to the INT_MIN overflow by swapping the comparison
8565 if necessary. */
8569 /* We now can look at the canonicalized case
8570 VARIABLE + 1 CODE2 INT_MIN
8571 and decide on the result. */
8573 {
8577 return
8583 return
8588 }
8589 }
8590 else
8591 {
8594 "when changing X +- C1 cmp C2 to "
8596 WARN_STRICT_OVERFLOW_COMPARISON);
8598 }
8599 }
8601 /* Transform comparisons of the form X - Y CMP 0 to X CMP Y. */
8603 && equality_code
8605 {
8606 /* ??? The transformation is valid for the other operators if overflow
8607 is undefined for the type, but performing it here badly interacts
8608 with the transformation in fold_cond_expr_with_comparison which
8609 attempts to synthetize ABS_EXPR. */
8613 WARN_STRICT_OVERFLOW_COMPARISON);
8616 }
8618 /* For comparisons of pointers we can decompose it to a compile time
8619 comparison of the base objects and the offsets into the object.
8620 This requires at least one operand being an ADDR_EXPR or a
8621 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8627 {
8630 machine_mode mode;
8634 /* Get base and offset for the access. Strip ADDR_EXPR for
8635 get_inner_reference, but put it back by stripping INDIRECT_REF
8636 off the base object if possible. indirect_baseN will be true
8637 if baseN is not an address but refers to the object itself. */
8640 {
8646 else
8648 }
8650 {
8654 {
8657 }
8660 {
8665 {
8668 }
8669 }
8670 }
8674 {
8680 else
8682 }
8684 {
8688 {
8691 }
8694 {
8699 {
8702 }
8703 }
8704 }
8706 /* A local variable can never be pointed to by
8707 the default SSA name of an incoming parameter. */
8709 && indirect_base0
8712 && !indirect_base1
8717 && indirect_base1
8720 && !indirect_base0
8724 {
8729 }
8730 /* If we have equivalent bases we might be able to simplify. */
8733 {
8734 /* We can fold this expression to a constant if the non-constant
8735 offset parts are equal. */
8744 {
8750 "occur when comparing P +- C1 with "
8752 WARN_STRICT_OVERFLOW_CONDITIONAL);
8755 {
8769 }
8770 }
8771 /* We can simplify the comparison to a comparison of the variable
8772 offset parts if the constant offset parts are equal.
8773 Be careful to use signed sizetype here because otherwise we
8774 mess with array offsets in the wrong way. This is possible
8775 because pointer arithmetic is restricted to retain within an
8776 object and overflow on pointer differences is undefined as of
8777 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8779 && (equality_code
8782 {
8783 /* By converting to signed sizetype we cover middle-end pointer
8784 arithmetic which operates on unsigned pointer types of size
8785 type size and ARRAY_REF offsets which are properly sign or
8786 zero extended from their type in case it is narrower than
8787 sizetype. */
8790 else
8794 else
8801 "occur when comparing P +- C1 with "
8803 WARN_STRICT_OVERFLOW_COMPARISON);
8806 }
8807 }
8808 /* For non-equal bases we can simplify if they are addresses
8809 of local binding decls or constants. */
8811 /* We know that !operand_equal_p (base0, base1, 0)
8812 because the if condition was false. But make
8813 sure two decls are not the same. */
8827 {
8834 }
8835 /* For equal offsets we can simplify to a comparison of the
8836 base addresses. */
8838 && (indirect_base0
8840 && (indirect_base1
8845 {
8851 }
8852 }
8854 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8855 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8856 the resulting offset is smaller in absolute value than the
8857 original one and has the same sign. */
8865 {
8870 tree cst;
8872 "occur when combining constants around "
8875 /* Put the constant on the side where it doesn't overflow and is
8876 of lower absolute value and of same sign than before. */
8883 {
8886 variable1,
8890 }
8898 {
8904 variable2);
8905 }
8906 }
8908 /* Transform comparisons of the form X * C1 CMP 0 to X CMP 0 in the
8909 signed arithmetic case. That form is created by the compiler
8910 often enough for folding it to be of value. One example is in
8911 computing loop trip counts after Operator Strength Reduction. */
8917 {
8923 /* Handle unfolded multiplication by zero. */
8928 "eliminating multiplication in comparison "
8930 WARN_STRICT_OVERFLOW_COMPARISON);
8932 /* If const1 is negative we swap the sense of the comparison. */
8937 }
8944 {
8952 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
8958 /* (-a) CMP (-b) -> b CMP a */
8965 {
8966 REAL_VALUE_TYPE cst;
8969 /* (-a) CMP CST -> a swap(CMP) (-CST) */
8976 /* IEEE doesn't distinguish +0 and -0 in comparisons. */
8977 /* a CMP (-0) -> a CMP 0 */
8982 /* x != NaN is always true, other ops are always false. */
8985 {
8988 }
8990 /* Fold comparisons against infinity. */
8993 {
8997 }
8998 }
9000 /* If this is a comparison of a real constant with a PLUS_EXPR
9001 or a MINUS_EXPR of a real constant, we can convert it into a
9002 comparison with a revised real constant as long as no overflow
9003 occurs when unsafe_math_optimizations are enabled. */
9015 /* Likewise, we can simplify a comparison of a real constant with
9016 a MINUS_EXPR whose first operand is also a real constant, i.e.
9017 (c1 - x) < c2 becomes x > c1-c2. Reordering is allowed on
9018 floating-point types only if -fassociative-math is set. */
9024 arg1))
9029 /* Fold comparisons against built-in math functions. */
9031 && flag_unsafe_math_optimizations
9033 {
9037 {
9041 }
9042 }
9043 }
9047 {
9048 /* If we are widening one operand of an integer comparison,
9049 see if the other operand is similarly being widened. Perhaps we
9050 can do the comparison in the narrower type. */
9055 /* Or if we are changing signedness. */
9059 }
9061 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
9062 constant, we can simplify it. */
9067 {
9071 }
9073 /* Simplify comparison of something with itself. (For IEEE
9074 floating-point, we can only do some of these simplifications.) */
9076 {
9078 {
9093 /* For NE, we can only do this simplification if integer
9094 or we don't honor IEEE floating point NaNs. */
9098 /* ... fall through ... */
9104 }
9105 }
9107 /* If we are comparing an expression that just has comparisons
9108 of two integer values, arithmetic expressions of those comparisons,
9109 and constants, we can simplify it. There are only three cases
9110 to check: the two values can either be equal, the first can be
9111 greater, or the second can be greater. Fold the expression for
9112 those three values. Since each value must be 0 or 1, we have
9113 eight possibilities, each of which corresponds to the constant 0
9114 or 1 or one of the six possible comparisons.
9116 This handles common cases like (a > b) == 0 but also handles
9117 expressions like ((x > y) - (y > x)) > 0, which supposedly
9118 occur in macroized code. */
9121 {
9126 /* Don't handle degenerate cases here; they should already
9127 have been handled anyway. */
9136 {
9140 /* We can't just pass T to eval_subst in case cval1 or cval2
9141 was the same as ARG1. */
9143 tree high_result
9147 arg1);
9148 tree equal_result
9152 arg1);
9153 tree low_result
9157 arg1);
9159 /* All three of these results should be 0 or 1. Confirm they are.
9160 Then use those values to select the proper code to use. */
9165 {
9166 /* Make a 3-bit mask with the high-order bit being the
9167 value for `>', the next for '=', and the low for '<'. */
9171 {
9173 /* Always false. */
9194 /* Always true. */
9196 }
9199 {
9203 }
9205 }
9206 }
9207 }
9209 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
9210 into a single range test. */
9218 {
9222 }
9224 /* Fold ~X op ~Y as Y op X. */
9227 {
9233 }
9235 /* Fold ~X op C as X op' ~C, where op' is the swapped comparison. */
9238 {
9244 }
9247 }
9250 /* Subroutine of fold_binary. Optimize complex multiplications of the
9251 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9252 argument EXPR represents the expression "z" of type TYPE. */
9254 static tree
9256 {
9261 {
9264 }
9266 {
9269 }
9270 else
9271 {
9275 }
9284 }
9287 /* Subroutine of fold_binary. If P is the value of EXPR, computes
9288 power-of-two M and (arbitrary) N such that M divides (P-N). This condition
9289 guarantees that P and N have the same least significant log2(M) bits.
9290 N is not otherwise constrained. In particular, N is not normalized to
9291 0 <= N < M as is common. In general, the precise value of P is unknown.
9292 M is chosen as large as possible such that constant N can be determined.
9294 Returns M and sets *RESIDUE to N.
9296 If ALLOW_FUNC_ALIGN is true, do take functions' DECL_ALIGN_UNIT into
9297 account. This is not always possible due to PR 35705.
9298 */
9300 static unsigned HOST_WIDE_INT
9303 {
9310 {
9315 }
9317 {
9325 allow_func_align);
9331 {
9334 }
9336 {
9339 {
9342 /* Compute the greatest power-of-2 divisor of op1. */
9346 /* If align is non-zero and less than *modulus, replace
9347 *modulus with align., If align is 0, then either op1 is 0
9348 or the greatest power-of-2 divisor of op1 doesn't fit in an
9349 unsigned HOST_WIDE_INT. In either case, no additional
9350 constraint is imposed. */
9355 }
9356 }
9357 }
9359 /* If we get here, we were unable to determine anything useful about the
9360 expression. */
9362 }
9364 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
9365 CONSTRUCTOR ARG into array ELTS and return true if successful. */
9367 static bool
9369 {
9373 {
9376 }
9378 {
9384 else
9386 }
9387 else
9393 }
9395 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9396 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9397 NULL_TREE otherwise. */
9399 static tree
9401 {
9418 {
9422 }
9425 {
9431 }
9432 else
9434 }
9436 /* Try to fold a pointer difference of type TYPE two address expressions of
9437 array references AREF0 and AREF1 using location LOC. Return a
9438 simplified expression for the difference or NULL_TREE. */
9440 static tree
9443 {
9448 /* If the bases are array references as well, recurse. If the bases
9449 are pointer indirections compute the difference of the pointers.
9450 If the bases are equal, we are set. */
9453 && (base_offset
9461 {
9467 base_offset,
9470 }
9472 }
9474 /* If the real or vector real constant CST of type TYPE has an exact
9475 inverse, return it, else return NULL. */
9477 static tree
9479 {
9480 REAL_VALUE_TYPE r;
9482 machine_mode mode;
9486 {
9502 {
9507 }
9513 }
9514 }
9516 /* Mask out the tz least significant bits of X of type TYPE where
9517 tz is the number of trailing zeroes in Y. */
9518 static wide_int
9520 {
9525 }
9527 /* Return true when T is an address and is known to be nonzero.
9528 For floating point we further ensure that T is not denormal.
9529 Similar logic is present in nonzero_address in rtlanal.h.
9531 If the return value is based on the assumption that signed overflow
9532 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9533 change *STRICT_OVERFLOW_P. */
9535 static bool
9537 {
9541 /* Doing something useful for floating point would need more work. */
9547 {
9550 strict_overflow_p);
9556 strict_overflow_p);
9564 }
9567 {
9570 strict_overflow_p);
9578 strict_overflow_p);
9593 strict_overflow_p);
9597 strict_overflow_p);
9600 {
9612 }
9616 }
9618 }
9620 /* Return true when T is an address and is known to be nonzero.
9621 Handle warnings about undefined signed overflow. */
9623 static bool
9625 {
9632 "determining that expression is always "
9634 WARN_STRICT_OVERFLOW_MISC);
9636 }
9638 /* Fold a binary expression of code CODE and type TYPE with operands
9639 OP0 and OP1. LOC is the location of the resulting expression.
9640 Return the folded expression if folding is successful. Otherwise,
9641 return NULL_TREE. */
9643 tree
9646 {
9661 /* Strip any conversions that don't change the mode. This is
9662 safe for every expression, except for a comparison expression
9663 because its signedness is derived from its operands. So, in
9664 the latter case, only strip conversions that don't change the
9665 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9666 preserved.
9668 Note that this is done as an internal manipulation within the
9669 constant folder, in order to find the simplest representation
9670 of the arguments so that their form can be studied. In any
9671 cases, the appropriate type conversions should be put back in
9672 the tree that will get out of the constant folder. */
9675 {
9678 }
9679 else
9680 {
9683 }
9685 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9686 constant but we can't do arithmetic on them. */
9694 {
9696 {
9697 /* Make sure type and arg0 have the same saturating flag. */
9701 }
9704 else
9708 {
9712 }
9713 }
9715 /* If this is a commutative operation, and ARG0 is a constant, move it
9716 to ARG1 to reduce the number of tests below. */
9721 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9722 to ARG1 to reduce the number of tests below. */
9731 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9733 First check for cases where an arithmetic operation is applied to a
9734 compound, conditional, or comparison operation. Push the arithmetic
9735 operation inside the compound or conditional to see if any folding
9736 can then be done. Convert comparison to conditional for this purpose.
9737 The also optimizes non-constant cases that used to be done in
9738 expand_expr.
9740 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9741 one of the operands is a comparison and the other is a comparison, a
9742 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9743 code below would make the expression more complex. Change it to a
9744 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9745 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9758 {
9762 boolean_type_node,
9770 }
9774 {
9776 {
9781 tem);
9782 }
9785 {
9790 tem);
9791 }
9796 {
9802 }
9807 {
9813 }
9814 }
9817 {
9819 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9822 {
9828 }
9830 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9833 {
9834 tree base;
9835 HOST_WIDE_INT coffset;
9844 }
9849 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9855 arg1),
9857 arg0)));
9859 /* PTR_CST +p CST -> CST1 */
9868 {
9869 /* X + (X / CST) * -CST is X % CST. */
9874 {
9883 cst0));
9884 }
9885 }
9887 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9888 one. Make sure the type is not saturating and has the signedness of
9889 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9890 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9897 {
9901 }
9904 {
9905 /* If we are adding two BIT_AND_EXPR's, both of which are and'ing
9906 with a constant, and the two constants have no bits in common,
9907 we should treat this as a BIT_IOR_EXPR since this may produce more
9908 simplifications. */
9915 {
9918 }
9920 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9921 (plus (plus (mult) (mult)) (foo)) so that we can
9922 take advantage of the factoring cases below. */
9930 {
9936 else
9949 parg0),
9951 marg)),
9955 return
9961 parg1)));
9962 }
9963 }
9964 else
9965 {
9966 /* See if ARG1 is zero and X + ARG1 reduces to X. */
9970 /* Likewise if the operands are reversed. */
9974 /* Convert X + -C into X - C. */
9977 {
9983 }
9985 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9986 to __complex__ ( x, y ). This is not the same for SNaNs or
9987 if signed zeros are involved. */
9991 {
9998 {
10002 {
10008 }
10010 {
10016 }
10017 }
10018 }
10026 /* Convert x+x into x*2.0. */
10032 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
10033 We associate floats only if the user has specified
10034 -fassociative-math. */
10038 {
10043 {
10044 tree tree0;
10047 }
10048 }
10049 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
10050 We associate floats only if the user has specified
10051 -fassociative-math. */
10055 {
10060 {
10061 tree tree0;
10064 }
10065 }
10066 }
10068 bit_rotate:
10069 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
10070 is a rotate of A by C1 bits. */
10071 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
10072 is a rotate of A by B bits. */
10073 {
10075 tree rtype;
10084 /* Only create rotates in complete modes. Other cases are not
10085 expanded properly. */
10088 {
10102 {
10108 }
10110 {
10118 element_precision
10122 return
10125 ? LROTATE_EXPR
10129 }
10131 {
10139 element_precision
10143 return fold_convert_loc
10146 ? LROTATE_EXPR
10150 }
10151 }
10152 }
10154 associate:
10155 /* In most languages, can't associate operations on floats through
10156 parentheses. Rather than remember where the parentheses were, we
10157 don't associate floats at all, unless the user has specified
10158 -fassociative-math.
10159 And, we need to make sure type is not saturating. */
10163 {
10169 /* Split both trees into variables, constants, and literals. Then
10170 associate each group together, the constants with literals,
10171 then the result with variables. This increases the chances of
10172 literals being recombined later and of generating relocatable
10173 expressions for the sum of a constant and literal. */
10178 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10182 /* With undefined overflow prefer doing association in a type
10183 which wraps on overflow, if that is one of the operand types. */
10186 {
10194 }
10196 /* With undefined overflow we can only associate constants with one
10197 variable, and constants whose association doesn't overflow. */
10200 {
10202 {
10220 /* The only case we can still associate with two variables
10221 is if they are the same, modulo negation and bit-pattern
10222 preserving conversions. */
10225 }
10226 }
10228 /* Only do something if we found more than two objects. Otherwise,
10229 nothing has changed and we risk infinite recursion. */
10235 {
10247 /* Preserve the MINUS_EXPR if the negative part of the literal is
10248 greater than the positive part. Otherwise, the multiplicative
10249 folding code (i.e extract_muldiv) may be fooled in case
10250 unsigned constants are subtracted, like in the following
10251 example: ((X*2 + 4) - 8U)/2. */
10253 {
10257 {
10261 }
10262 else
10263 {
10267 }
10268 }
10270 /* Don't introduce overflows through reassociation. */
10277 {
10279 return
10283 else
10284 {
10287 return
10291 }
10292 }
10295 return
10298 }
10299 }
10304 /* Pointer simplifications for subtraction, simple reassociations. */
10306 {
10307 /* (PTR0 p+ A) - (PTR1 p+ B) -> (PTR0 - PTR1) + (A - B) */
10310 {
10320 }
10321 /* (PTR0 p+ A) - PTR1 -> (PTR0 - PTR1) + A, assuming PTR0 - PTR1 simplifies. */
10323 {
10330 }
10331 /* PTR0 - (PTR1 p+ A) -> (PTR0 - PTR1) - A, assuming PTR0 - PTR1
10332 simplifies. */
10334 {
10341 arg10);
10344 }
10345 }
10346 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10355 /* Convert -A - 1 to ~A. */
10363 /* Convert -1 - A to ~A. */
10369 /* X - (X / Y) * Y is X % Y. */
10377 return
10383 {
10387 /* Fold A - (A & B) into ~B & A. */
10390 {
10392 {
10399 }
10401 {
10408 }
10409 }
10411 /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
10412 any power of 2 minus 1. */
10417 {
10423 {
10427 }
10428 }
10429 }
10431 /* See if ARG1 is zero and X - ARG1 reduces to X. */
10435 /* (ARG0 - ARG1) is the same as (-ARG1 + ARG0). So check whether
10436 ARG0 is zero and X + ARG0 reduces to X, since that would mean
10437 (-ARG1 + ARG0) reduces to -ARG1. */
10441 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10442 __complex__ ( x, -y ). This is not the same for SNaNs or if
10443 signed zeros are involved. */
10447 {
10454 {
10458 {
10460 arg1r ? arg1r
10465 }
10467 {
10471 arg1i ? arg1i
10474 }
10475 }
10476 }
10478 /* A - B -> A + (-B) if B is easily negatable. */
10482 /* Avoid this transformation if B is a positive REAL_CST. */
10491 /* Try folding difference of addresses. */
10492 {
10493 HOST_WIDE_INT diff;
10499 }
10501 /* Fold &a[i] - &a[j] to i-j. */
10506 {
10512 }
10515 && flag_unsafe_math_optimizations
10521 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
10522 one. Make sure the type is not saturating and has the signedness of
10523 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10524 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10531 {
10535 }
10540 /* (-A) * (-B) -> A * B */
10555 {
10556 /* Transform x * -1 into -x. Make sure to do the negation
10557 on the original operand with conversions not stripped
10558 because we can only strip non-sign-changing conversions. */
10561 /* Transform x * -C into -x * C if x is easily negatable. */
10570 tem);
10572 /* (a * (1 << b)) is (a << b) */
10582 /* (A + A) * C -> A * 2 * C */
10594 /* ((T) (X /[ex] C)) * C cancels out if the conversion is
10595 sign-changing only. */
10605 {
10608 "occur when simplifying "
10610 WARN_STRICT_OVERFLOW_MISC);
10612 }
10614 /* Optimize z * conj(z) for integer complex numbers. */
10621 }
10622 else
10623 {
10624 /* Maybe fold x * 0 to 0. The expressions aren't the same
10625 when x is NaN, since x * 0 is also NaN. Nor are they the
10626 same in modes with signed zeros, since multiplying a
10627 negative value by 0 gives -0, not +0. */
10632 /* In IEEE floating point, x*1 is not equivalent to x for snans.
10633 Likewise for complex arithmetic with signed zeros. */
10640 /* Transform x * -1.0 into -x. */
10647 /* Convert (C1/X)*C2 into (C1*C2)/X. This transformation may change
10648 the result for floating point types due to rounding so it is applied
10649 only if -fassociative-math was specify. */
10654 {
10656 arg1);
10660 }
10662 /* Strip sign operations from X in X*X, i.e. -Y*-Y -> Y*Y. */
10664 {
10667 {
10670 }
10671 }
10673 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10674 This is not the same for NaNs or if signed zeros are
10675 involved. */
10681 {
10684 return
10690 return
10695 }
10697 /* Optimize z * conj(z) for floating point complex numbers.
10698 Guarded by flag_unsafe_math_optimizations as non-finite
10699 imaginary components don't produce scalar results. */
10710 {
10714 /* Optimizations of root(...)*root(...). */
10716 {
10721 /* Optimize sqrt(x)*sqrt(x) as x. */
10727 /* Optimize root(x)*root(y) as root(x*y). */
10731 }
10733 /* Optimize expN(x)*expN(y) as expN(x+y). */
10735 {
10741 }
10743 /* Optimizations of pow(...)*pow(...). */
10747 {
10753 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y). */
10755 {
10760 }
10762 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z). */
10764 {
10769 }
10770 }
10772 /* Optimize tan(x)*cos(x) as sin(x). */
10781 {
10787 }
10789 /* Optimize x*pow(x,c) as pow(x,c+1). */
10793 {
10799 {
10801 REAL_VALUE_TYPE c;
10802 tree arg;
10808 }
10809 }
10811 /* Optimize pow(x,c)*x as pow(x,c+1). */
10815 {
10821 {
10823 REAL_VALUE_TYPE c;
10824 tree arg;
10830 }
10831 }
10833 /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x. */
10835 && optimize
10837 {
10841 {
10844 }
10845 }
10846 }
10847 }
10851 bit_ior:
10852 /* ~X | X is -1. */
10855 {
10859 }
10861 /* X | ~X is -1. */
10864 {
10868 }
10870 /* Canonicalize (X & C1) | C2. */
10874 {
10879 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10887 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10892 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10893 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10894 mode which allows further optimizations. */
10899 {
10903 {
10906 }
10907 }
10914 c3)),
10915 arg1);
10916 }
10918 /* (X & ~Y) | (~X & Y) is X ^ Y */
10921 {
10938 }
10944 /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
10946 This results in more efficient code for machines without a NAND
10947 instruction. Combine will canonicalize to the first form
10948 which will allow use of NAND instructions provided by the
10949 backend if they exist. */
10952 {
10953 return
10960 }
10962 /* See if this can be simplified into a rotate first. If that
10963 is unsuccessful continue in the association code. */
10967 /* ~X ^ X is -1. */
10970 {
10974 }
10976 /* X ^ ~X is -1. */
10979 {
10983 }
10985 /* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
10986 with a constant, and the two constants have no bits in common,
10987 we should treat this as a BIT_IOR_EXPR since this may produce more
10988 simplifications. */
10995 {
10998 }
11000 /* (X | Y) ^ X -> Y & ~ X*/
11003 {
11006 arg1);
11011 }
11013 /* (Y | X) ^ X -> Y & ~ X*/
11016 {
11019 arg1);
11024 }
11026 /* X ^ (X | Y) -> Y & ~ X*/
11029 {
11032 arg0);
11037 }
11039 /* X ^ (Y | X) -> Y & ~ X*/
11042 {
11045 arg0);
11050 }
11052 /* Convert ~X ^ ~Y to X ^ Y. */
11061 /* Convert ~X ^ C to X ^ ~C. */
11069 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11077 /* Fold (X & Y) ^ Y as ~X & Y. */
11080 {
11085 }
11086 /* Fold (X & Y) ^ X as ~Y & X. */
11090 {
11095 }
11096 /* Fold X ^ (X & Y) as X & ~Y. */
11099 {
11104 }
11105 /* Fold X ^ (Y & X) as ~Y & X. */
11109 {
11114 }
11116 /* See if this can be simplified into a rotate first. If that
11117 is unsuccessful continue in the association code. */
11121 /* ~X & X, (X == 0) & X, and !X & X are always zero. */
11129 /* X & ~X , X & (X == 0), and X & !X are always zero. */
11137 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11142 {
11143 tree tem2;
11150 }
11151 /* Fold ~X & 1 as (X & 1) == 0. */
11155 {
11156 tree tem2;
11163 }
11164 /* Fold !X & 1 as X == 0. */
11167 {
11171 }
11173 /* Fold (X ^ Y) & Y as ~X & Y. */
11176 {
11181 }
11182 /* Fold (X ^ Y) & X as ~Y & X. */
11186 {
11191 }
11192 /* Fold X & (X ^ Y) as X & ~Y. */
11195 {
11200 }
11201 /* Fold X & (Y ^ X) as ~Y & X. */
11205 {
11210 }
11212 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11213 multiple of 1 << CST. */
11215 {
11222 }
11224 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11225 bits from CST2. */
11229 {
11237 {
11238 /* Avoid the transform if arg1 is a mask of some
11239 mode which allows further optimizations. */
11246 }
11247 }
11249 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
11250 ((A & N) + B) & M -> (A + B) & M
11251 Similarly if (N & M) == 0,
11252 ((A | N) + B) & M -> (A + B) & M
11253 and for - instead of + (or unary - instead of +)
11254 and/or ^ instead of |.
11255 If B is constant and (B & M) == 0, fold into A & M. */
11257 {
11266 {
11269 wide_int cst0;
11271 /* Now we know that arg0 is (C + D) or (C - D) or
11272 -C and arg1 (M) is == (1LL << cst) - 1.
11273 Store C into PMOP[0] and D into PMOP[1]. */
11277 {
11280 }
11287 {
11297 {
11300 }
11303 /* If C or D is of the form (A & N) where
11304 (N & M) == M, or of the form (A | N) or
11305 (A ^ N) where (N & M) == 0, replace it with A. */
11309 /* If C or D is a N where (N & M) == 0, it can be
11310 omitted (assumed 0). */
11318 }
11320 /* Only build anything new if we optimized one or both arguments
11321 above. */
11325 {
11328 {
11329 /* Perform the operations in a type that has defined
11330 overflow behavior. */
11336 }
11341 {
11349 else
11351 }
11354 else
11357 /* TEM is now the new binary +, - or unary - replacement. */
11361 }
11362 }
11363 }
11368 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11371 {
11376 return
11378 }
11380 /* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
11382 This results in more efficient code for machines without a NOR
11383 instruction. Combine will canonicalize to the first form
11384 which will allow use of NOR instructions provided by the
11385 backend if they exist. */
11388 {
11395 }
11397 /* If arg0 is derived from the address of an object or function, we may
11398 be able to fold this expression using the object or function's
11399 alignment. */
11401 {
11408 /* This works because modulus is a power of 2. If this weren't the
11409 case, we'd have to replace it by its greatest power-of-2
11410 divisor: modulus & -modulus. */
11413 }
11415 /* Fold (X << C1) & C2 into (X << C1) & (C2 | ((1 << C1) - 1))
11416 (X >> C1) & C2 into (X >> C1) & (C2 | ~((type) -1 >> C1))
11417 if the new mask might be further optimized. */
11426 {
11437 {
11440 /* See if more bits can be proven as zero because of
11441 zero extension. */
11444 {
11449 {
11451 /* See if we can shorten the right shift. */
11454 /* Otherwise X >> C1 is all zeros, so we'll optimize
11455 it into (X, 0) later on by making sure zerobits
11456 is all ones. */
11457 }
11458 }
11461 {
11464 }
11465 /* For arithmetic shift if sign bit could be set, zerobits
11466 can contain actually sign bits, so no transformation is
11467 possible, unless MASK masks them all away. In that
11468 case the shift needs to be converted into logical shift. */
11471 {
11474 else
11476 }
11477 }
11479 /* ((X << 16) & 0xff00) is (X, 0). */
11486 {
11487 /* Only do the transformation if NEWMASK is some integer
11488 mode's mask. */
11495 {
11496 tree newmaskt;
11499 {
11505 }
11506 else
11511 }
11512 }
11513 }
11518 /* Don't touch a floating-point divide by zero unless the mode
11519 of the constant can represent infinity. */
11525 /* Optimize A / A to 1.0 if we don't care about
11526 NaNs or Infinities. Skip the transformation
11527 for non-real operands. */
11532 {
11536 }
11538 /* The complex version of the above A / A optimization. */
11541 {
11545 {
11547 /* omit_two_operands will call fold_convert for us. */
11549 }
11550 }
11552 /* (-A) / (-B) -> A / B */
11562 /* In IEEE floating point, x/1 is not equivalent to x for snans. */
11567 /* In IEEE floating point, x/-1 is not equivalent to -x for snans. */
11573 /* If ARG1 is a constant, we can convert this to a multiply by the
11574 reciprocal. This does not have the same rounding properties,
11575 so only do this if -freciprocal-math. We can actually
11576 always safely do it if ARG1 is a power of two, but it's hard to
11577 tell if it is or not in a portable manner. */
11584 {
11588 /* Find the reciprocal if optimizing and the result is exact.
11589 TODO: Complex reciprocal not implemented. */
11591 {
11596 }
11597 }
11598 /* Convert A/B/C to A/(B*C). */
11605 /* Convert A/(B/C) to (A/B)*C. */
11613 /* Convert C1/(X*C2) into (C1/C2)/X. */
11618 {
11624 }
11627 {
11631 /* Optimize sin(x)/cos(x) as tan(x). */
11637 {
11642 }
11644 /* Optimize cos(x)/sin(x) as 1.0/tan(x). */
11650 {
11654 {
11659 }
11660 }
11662 /* Optimize sin(x)/tan(x) as cos(x) if we don't care about
11663 NaNs or Infinities. */
11667 {
11674 {
11679 }
11680 }
11682 /* Optimize tan(x)/sin(x) as 1.0/cos(x) if we don't care about
11683 NaNs or Infinities. */
11687 {
11694 {
11698 {
11702 tmp);
11703 }
11704 }
11705 }
11707 /* Optimize pow(x,c)/x as pow(x,c-1). */
11711 {
11717 {
11719 REAL_VALUE_TYPE c;
11720 tree arg;
11726 }
11727 }
11729 /* Optimize a/root(b/c) into a*root(c/b). */
11731 {
11735 {
11744 }
11745 }
11747 /* Optimize x/expN(y) into x*expN(-y). */
11749 {
11756 }
11758 /* Optimize x/pow(y,z) into x*pow(y,-z). */
11762 {
11770 }
11771 }
11775 /* Optimize (X & (-A)) / A where A is a power of 2,
11776 to X >> log2(A) */
11780 {
11788 }
11789 }
11791 /* Fall through */
11794 /* Simplify A / (B << N) where A and B are positive and B is
11795 a power of 2, to A >> (N + log2(B)). */
11800 {
11803 {
11811 WARN_STRICT_OVERFLOW_MISC);
11817 }
11818 }
11820 /* For unsigned integral types, FLOOR_DIV_EXPR is the same as
11821 TRUNC_DIV_EXPR. Rewrite into the latter in this case. */
11827 /* Fall through */
11834 /* X / -1 is -X. */
11840 /* Convert -A / -B to A / B when the type is signed and overflow is
11841 undefined. */
11845 {
11848 "when distributing negation across "
11850 WARN_STRICT_OVERFLOW_MISC);
11856 }
11860 {
11863 "when distributing negation across "
11865 WARN_STRICT_OVERFLOW_MISC);
11871 }
11873 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11874 operation, EXACT_DIV_EXPR.
11876 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11877 At one time others generated faster code, it's not clear if they do
11878 after the last round to changes to the DIV code in expmed.c. */
11887 {
11891 WARN_STRICT_OVERFLOW_MISC);
11893 }
11901 /* X % -1 is zero. */
11907 /* X % -C is the same as X % C. */
11914 /* Avoid this transformation if C is INT_MIN, i.e. C == -C. */
11921 /* X % -Y is the same as X % Y. */
11934 {
11938 WARN_STRICT_OVERFLOW_MISC);
11940 }
11942 /* Optimize TRUNC_MOD_EXPR by a power of two into a BIT_AND_EXPR,
11943 i.e. "X % C" into "X & (C - 1)", if X and C are positive. */
11947 {
11949 /* Also optimize A % (C << N) where C is a power of 2,
11950 to A & ((C << N) - 1). */
11955 {
11956 tree mask
11961 "occur when simplifying "
11963 WARN_STRICT_OVERFLOW_MISC);
11967 }
11968 }
11979 /* Optimize -1 >> x for arithmetic right shifts. */
11983 /* ... fall through ... */
11986 shift:
11992 /* Prefer vector1 << scalar to vector1 << vector2
11993 if vector2 is uniform. */
11998 /* Since negative shift count is not well-defined,
11999 don't try to compute it in the compiler. */
12005 /* Turn (a OP c1) OP c2 into a OP (c1+c2). */
12010 {
12014 /* Deal with a OP (c1 + c2) being undefined but (a OP c1) OP c2
12015 being well defined. */
12017 {
12023 else
12025 }
12029 }
12031 /* Transform (x >> c) << c into x & (-1<<c), or transform (x << c) >> c
12032 into x & ((unsigned)-1 >> c) for unsigned types. */
12040 {
12043 tree lshift;
12044 tree arg00;
12047 {
12054 }
12055 }
12057 /* Rewrite an LROTATE_EXPR by a constant into an
12058 RROTATE_EXPR by a new constant. */
12060 {
12064 }
12066 /* If we have a rotate of a bit operation with the rotate count and
12067 the second operand of the bit operation both constant,
12068 permute the two operations. */
12080 /* Two consecutive rotates adding up to the some integer
12081 multiple of the precision of the type can be ignored. */
12089 /* Fold (X & C2) << C1 into (X << C1) & (C2 << C1)
12090 (X & C2) >> C1 into (X >> C1) & (C2 >> C1)
12091 if the latter can be further optimized. */
12096 {
12100 arg1);
12104 arg1);
12108 }
12136 /* Note that the operands of this must be ints
12137 and their values must be 0 or 1.
12138 ("true" is a fixed value perhaps depending on the language.) */
12139 /* If first arg is constant zero, return it. */
12143 /* If either arg is constant true, drop it. */
12147 /* Preserve sequence points. */
12150 /* If second arg is constant zero, result is zero, but first arg
12151 must be evaluated. */
12154 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
12155 case will be handled here. */
12159 /* !X && X is always false. */
12163 /* X && !X is always false. */
12168 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
12169 means A >= Y && A != MAX, but in this case we know that
12170 A < X <= MAX. */
12174 {
12182 }
12191 /* Note that the operands of this must be ints
12192 and their values must be 0 or true.
12193 ("true" is a fixed value perhaps depending on the language.) */
12194 /* If first arg is constant true, return it. */
12198 /* If either arg is constant zero, drop it. */
12202 /* Preserve sequence points. */
12205 /* If second arg is constant true, result is true, but we must
12206 evaluate first arg. */
12209 /* Likewise for first arg, but note this only occurs here for
12210 TRUTH_OR_EXPR. */
12214 /* !X || X is always true. */
12218 /* X || !X is always true. */
12223 /* (X && !Y) || (!X && Y) is X ^ Y */
12226 {
12243 }
12252 /* If the second arg is constant zero, drop it. */
12255 /* If the second arg is constant true, this is a logical inversion. */
12257 {
12260 }
12261 /* Identical arguments cancel to zero. */
12265 /* !X ^ X is always true. */
12270 /* X ^ !X is always true. */
12286 /* bool_var != 0 becomes bool_var. */
12291 /* bool_var == 1 becomes bool_var. */
12296 /* bool_var != 1 becomes !bool_var. */
12303 /* bool_var == 0 becomes !bool_var. */
12310 /* !exp != 0 becomes !exp */
12315 /* If this is an equality comparison of the address of two non-weak,
12316 unaliased symbols neither of which are extern (since we do not
12317 have access to attributes for externs), then we know the result. */
12330 {
12331 /* We know that we're looking at the address of two
12332 non-weak, unaliased, static _DECL nodes.
12334 It is both wasteful and incorrect to call operand_equal_p
12335 to compare the two ADDR_EXPR nodes. It is wasteful in that
12336 all we need to do is test pointer equality for the arguments
12337 to the two ADDR_EXPR nodes. It is incorrect to use
12338 operand_equal_p as that function is NOT equivalent to a
12339 C equality test. It can in fact return false for two
12340 objects which would test as equal using the C equality
12341 operator. */
12345 type);
12346 }
12348 /* Similarly for a NEGATE_EXPR. */
12352 arg1)))
12357 /* Similarly for a BIT_XOR_EXPR; X ^ C1 == C2 is X == (C1 ^ C2). */
12365 arg1),
12368 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
12377 {
12381 val,
12385 }
12387 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
12394 {
12396 code == NE_EXPR
12399 }
12401 /* Convert ABS_EXPR<x> == 0 or ABS_EXPR<x> != 0 to x == 0 or x != 0. */
12406 /* If this is an EQ or NE comparison with zero and ARG0 is
12407 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12408 two operations, but the latter can be done in one less insn
12409 on machines that have only two-operand insns or on which a
12410 constant cannot be the first operand. */
12413 {
12418 {
12425 arg1);
12426 }
12429 {
12436 arg1);
12437 }
12438 }
12440 /* If this is an NE or EQ comparison of zero against the result of a
12441 signed MOD operation whose second operand is a power of 2, make
12442 the MOD operation unsigned since it is simpler and equivalent. */
12450 {
12460 }
12462 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12463 C1 is a valid shift constant, and C2 is a power of two, i.e.
12464 a single bit. */
12468 == INTEGER_CST
12471 {
12476 /* Check for a valid shift count. */
12478 {
12482 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
12483 can be rewritten as (X & (C2 << C1)) != 0. */
12485 {
12490 }
12491 /* Otherwise, for signed (arithmetic) shifts,
12492 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12493 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12497 /* Otherwise, of unsigned (logical) shifts,
12498 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12499 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12500 else
12504 arg000);
12505 }
12506 }
12508 /* If we have (A & C) == C where C is a power of 2, convert this into
12509 (A & C) != 0. Similarly for NE_EXPR. */
12515 integer_zero_node));
12517 /* If we have (A & C) != 0 or (A & C) == 0 and C is the sign
12518 bit, then fold the expression into A < 0 or A >= 0. */
12523 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
12524 Similarly for NE_EXPR. */
12528 {
12532 tree dandnotc
12535 notc);
12539 }
12541 /* If we have (A | C) == D where C & ~D != 0, convert this into 0.
12542 Similarly for NE_EXPR. */
12546 {
12548 tree candnotd
12555 }
12557 /* If this is a comparison of a field, we may be able to simplify it. */
12560 /* Handle the constant case even without -O
12561 to make sure the warnings are given. */
12563 {
12567 }
12569 /* Optimize comparisons of strlen vs zero to a compare of the
12570 first character of the string vs zero. To wit,
12571 strlen(ptr) == 0 => *ptr == 0
12572 strlen(ptr) != 0 => *ptr != 0
12573 Other cases should reduce to one of these two (or a constant)
12574 due to the return value of strlen being unsigned. */
12577 {
12585 {
12590 }
12591 }
12593 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12594 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12598 {
12603 {
12605 {
12608 }
12611 }
12612 }
12614 /* (X ^ Y) == 0 becomes X == Y, and (X ^ Y) != 0 becomes X != Y. */
12620 /* (X ^ Y) == Y becomes X == 0. We know that Y has no side-effects. */
12625 /* Likewise (X ^ Y) == X becomes Y == 0. X has no side-effects. */
12632 /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */
12640 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12641 (X & C) == 0 when C is a single bit. */
12646 {
12653 arg1));
12654 }
12656 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12657 constant C is a power of two, i.e. a single bit. */
12664 {
12668 }
12670 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12671 when is C is a power of two, i.e. a single bit. */
12678 {
12684 }
12688 {
12691 }
12693 /* Fold -X op -Y as X op Y, where op is eq/ne. */
12701 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
12704 {
12717 arg01),
12726 arg01),
12735 arg00),
12744 arg00),
12746 }
12750 {
12757 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12758 operand_equal_p guarantees no side-effects so we don't need
12759 to use omit_one_operand on Z. */
12763 arg10));
12767 arg11));
12771 arg10));
12775 arg11));
12777 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12780 {
12786 }
12787 }
12789 /* Attempt to simplify equality/inequality comparisons of complex
12790 values. Only lower the comparison if the result is known or
12791 can be simplified to a single scalar comparison. */
12796 {
12801 {
12804 }
12805 else
12806 {
12809 }
12812 {
12815 }
12816 else
12817 {
12820 }
12824 {
12826 {
12831 }
12832 else
12833 {
12838 }
12839 }
12843 {
12845 {
12850 }
12851 else
12852 {
12857 }
12858 }
12859 }
12871 /* Transform comparisons of the form X +- C CMP X. */
12878 {
12885 else
12888 /* (X - c) > X becomes false. */
12892 {
12896 "occur when assuming that (X - c) > X "
12898 WARN_STRICT_OVERFLOW_ALL);
12900 }
12902 /* Likewise (X + c) < X becomes false. */
12906 {
12910 "occur when assuming that "
12912 WARN_STRICT_OVERFLOW_ALL);
12914 }
12916 /* Convert (X - c) <= X to true. */
12921 {
12925 "occur when assuming that "
12927 WARN_STRICT_OVERFLOW_ALL);
12929 }
12931 /* Convert (X + c) >= X to true. */
12936 {
12940 "occur when assuming that "
12942 WARN_STRICT_OVERFLOW_ALL);
12944 }
12947 {
12948 /* Convert X + c > X and X - c < X to true for integers. */
12952 {
12955 "not occur when assuming that "
12957 WARN_STRICT_OVERFLOW_ALL);
12959 }
12964 {
12967 "not occur when assuming that "
12969 WARN_STRICT_OVERFLOW_ALL);
12971 }
12973 /* Convert X + c <= X and X - c >= X to false for integers. */
12977 {
12980 "not occur when assuming that "
12982 WARN_STRICT_OVERFLOW_ALL);
12984 }
12989 {
12992 "not occur when assuming that "
12994 WARN_STRICT_OVERFLOW_ALL);
12996 }
12997 }
12998 }
13000 /* Comparisons with the highest or lowest possible integer of
13001 the specified precision will have known values. */
13002 {
13008 {
13015 {
13028 /* The GE_EXPR and LT_EXPR cases above are not normally
13029 reached because of previous transformations. */
13033 }
13036 {
13043 arg1);
13049 arg0),
13050 arg1);
13053 }
13056 {
13071 }
13074 {
13081 arg1);
13087 arg0),
13088 arg1);
13091 }
13095 /* We will flip the signedness of the comparison operator
13096 associated with the mode of arg1, so the sign bit is
13097 specified by this mode. Check that arg1 is the signed
13098 max associated with this sign bit. */
13100 /* signed_type does not work on pointer types. */
13102 {
13103 /* The following case also applies to X < signed_max+1
13104 and X >= signed_max+1 because previous transformations. */
13106 {
13112 }
13113 }
13114 }
13115 }
13117 /* If we are comparing an ABS_EXPR with a constant, we can
13118 convert all the cases into explicit comparisons, but they may
13119 well not be faster than doing the ABS and one comparison.
13120 But ABS (X) <= C is a range comparison, which becomes a subtraction
13121 and a comparison, and is probably faster. */
13135 /* Convert ABS_EXPR<x> >= 0 to true. */
13142 {
13145 "when simplifying comparison of "
13147 WARN_STRICT_OVERFLOW_CONDITIONAL);
13150 arg0);
13151 }
13153 /* Convert ABS_EXPR<x> < 0 to false. */
13158 {
13161 "when simplifying comparison of "
13163 WARN_STRICT_OVERFLOW_CONDITIONAL);
13166 arg0);
13167 }
13169 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
13170 and similarly for >= into !=. */
13180 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
13181 otherwise Y might be >= # of bits in X's type and thus e.g.
13182 (unsigned char) (1 << Y) for Y 15 might be 0.
13183 If the cast is widening, then 1 << Y should have unsigned type,
13184 otherwise if Y is number of bits in the signed shift type minus 1,
13185 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
13186 31 might be 0xffffffff80000000. */
13197 {
13203 }
13216 {
13220 }
13222 /* If the first operand is NaN, the result is constant. */
13226 {
13228 ? integer_zero_node
13231 }
13233 /* If the second operand is NaN, the result is constant. */
13237 {
13239 ? integer_zero_node
13242 }
13244 /* Simplify unordered comparison of something with itself. */
13250 && !flag_trapping_math
13254 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
13255 {
13267 }
13272 /* When pedantic, a compound expression can be neither an lvalue
13273 nor an integer constant expression. */
13276 /* Don't let (0, 0) be null pointer constant. */
13290 /* An ASSERT_EXPR should never be passed to fold_binary. */
13295 {
13310 {
13316 }
13319 }
13325 {
13350 {
13363 }
13366 }
13371 }
13373 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
13374 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
13375 of GOTO_EXPR. */
13377 static tree
13379 {
13381 {
13388 /* ... fall through ... */
13392 }
13393 }
13395 /* Return whether the sub-tree ST contains a label which is accessible from
13396 outside the sub-tree. */
13398 static bool
13400 {
13401 return
13403 }
13405 /* Fold a ternary expression of code CODE and type TYPE with operands
13406 OP0, OP1, and OP2. Return the folded expression if folding is
13407 successful. Otherwise, return NULL_TREE. */
13409 tree
13412 {
13413 tree tem;
13420 /* If this is a commutative operation, and OP0 is a constant, move it
13421 to OP1 to reduce the number of tests below. */
13430 /* Strip any conversions that don't change the mode. This is safe
13431 for every expression, except for a comparison expression because
13432 its signedness is derived from its operands. So, in the latter
13433 case, only strip conversions that don't change the signedness.
13435 Note that this is done as an internal manipulation within the
13436 constant folder, in order to find the simplest representation of
13437 the arguments so that their form can be studied. In any cases,
13438 the appropriate type conversions should be put back in the tree
13439 that will get out of the constant folder. */
13441 {
13444 }
13447 {
13450 }
13453 {
13456 }
13459 {
13463 {
13469 }
13474 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
13475 so all simple results must be passed through pedantic_non_lvalue. */
13477 {
13480 /* Only optimize constant conditions when the selected branch
13481 has the same type as the COND_EXPR. This avoids optimizing
13482 away "c ? x : throw", where the throw has a void type.
13483 Avoid throwing away that operand which contains label. */
13490 }
13492 {
13497 {
13502 {
13510 }
13514 }
13515 }
13517 /* If we have A op B ? A : C, we may be able to convert this to a
13518 simpler expression, depending on the operation and the values
13519 of B and C. Signed zeros prevent all of these transformations,
13520 for reasons given above each one.
13522 Also try swapping the arguments and inverting the conditional. */
13527 {
13531 }
13535 op2,
13538 {
13542 {
13546 }
13547 }
13549 /* If the second operand is simpler than the third, swap them
13550 since that produces better jump optimization results. */
13553 {
13555 /* See if this can be inverted. If it can't, possibly because
13556 it was a floating-point inequality comparison, don't do
13557 anything. */
13561 }
13563 /* Convert A ? 1 : 0 to simply A. */
13568 /* If we try to convert OP0 to our type, the
13569 call to fold will try to move the conversion inside
13570 a COND, which will recurse. In that case, the COND_EXPR
13571 is probably the best choice, so leave it alone. */
13575 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
13576 over COND_EXPR in cases such as floating point comparisons. */
13585 arg0)));
13587 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
13592 {
13593 /* sign_bit_p looks through both zero and sign extensions,
13594 but for this optimization only sign extensions are
13595 usable. */
13598 {
13601 {
13604 }
13606 }
13607 /* sign_bit_p only checks ARG1 bits within A's precision.
13608 If <sign bit of A> has wider type than A, bits outside
13609 of A's precision in <sign bit of A> need to be checked.
13610 If they are all 0, this optimization needs to be done
13611 in unsigned A's type, if they are all 1 in signed A's type,
13612 otherwise this can't be done. */
13618 {
13620 tree tem_type;
13633 {
13636 }
13638 {
13641 }
13642 else
13644 }
13647 return
13653 arg1)));
13654 }
13656 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13657 already handled above. */
13662 {
13671 }
13673 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13674 is probably obsolete because the first operand should be a
13675 truth value (that's why we have the two cases above), but let's
13676 leave it in until we can confirm this for all front-ends. */
13688 /* Disable the transformations below for vectors, since
13689 fold_binary_op_with_conditional_arg may undo them immediately,
13690 yielding an infinite loop. */
13694 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13703 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13708 {
13710 /* Only perform transformation if ARG0 is easily inverted. */
13714 ? BIT_IOR_EXPR
13717 arg1);
13718 }
13720 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13725 {
13727 /* Only perform transformation if ARG0 is easily inverted. */
13733 op2);
13734 }
13736 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13748 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13749 of fold_ternary on them. */
13759 {
13769 {
13774 {
13782 }
13784 /* Constructor elements can be subvectors. */
13787 {
13791 }
13793 /* We keep an exact subset of the constructor elements. */
13795 {
13801 {
13805 }
13813 CONSTRUCTOR_ELT
13816 }
13817 /* The bitfield references a single constructor element. */
13819 {
13824 else
13828 }
13829 }
13830 }
13832 /* A bit-field-ref that referenced the full argument can be stripped. */
13838 /* On constants we can use native encode/interpret to constant
13839 fold (nearly) all BIT_FIELD_REFs. */
13843 /* This limitation should not be necessary, we just need to
13844 round this up to mode size. */
13846 /* Need bit-shifting of the buffer to relax the following. */
13848 {
13853 /* ??? We cannot tell native_encode_expr to start at
13854 some random byte only. So limit us to a reasonable amount
13855 of work. */
13857 {
13862 {
13868 }
13869 }
13870 }
13875 /* For integers we can decompose the FMA if possible. */
13887 {
13903 {
13908 /* Make sure that the perm value is in an acceptable
13909 range. */
13918 else
13923 }
13926 {
13931 }
13936 {
13941 }
13947 {
13951 }
13956 /* Some targets are deficient and fail to expand a single
13957 argument permutation while still allowing an equivalent
13958 2-argument version. */
13962 {
13965 }
13968 {
13975 }
13979 }
13985 }
13987 /* Perform constant folding and related simplification of EXPR.
13988 The related simplifications include x*1 => x, x*0 => 0, etc.,
13989 and application of the associative law.
13990 NOP_EXPR conversions may be removed freely (as long as we
13991 are careful not to change the type of the overall expression).
13992 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13993 but we can constant-fold them if they have constant operands. */
13995 #ifdef ENABLE_FOLD_CHECKING
13996 # define fold(x) fold_1 (x)
13998 static
13999 #endif
14000 tree
14002 {
14006 tree tem;
14009 /* Return right away if a constant. */
14013 /* CALL_EXPR-like objects with variable numbers of operands are
14014 treated specially. */
14016 {
14018 {
14021 }
14023 }
14026 {
14031 {
14049 }
14050 }
14053 {
14055 {
14062 {
14067 /* Find a matching index by means of a binary search. */
14069 {
14085 else
14087 }
14088 }
14091 }
14093 /* Return a VECTOR_CST if possible. */
14095 {
14102 tree value;
14105 {
14109 {
14112 }
14113 else
14115 }
14120 }
14128 }
14130 #ifdef ENABLE_FOLD_CHECKING
14131 #undef fold
14138 /* When --enable-checking=fold, compute a digest of expr before
14139 and after actual fold call to see if fold did not accidentally
14140 change original expr. */
14142 tree
14144 {
14145 tree ret;
14165 }
14167 void
14169 {
14180 }
14182 static void
14184 {
14186 }
14188 static void
14191 {
14197 recursive_label:
14207 {
14208 /* Allow DECL_ASSEMBLER_NAME to be modified. */
14212 }
14219 {
14220 /* Allow these fields to be modified. */
14221 tree tmp;
14229 {
14232 }
14233 }
14244 {
14247 {
14262 }
14266 {
14279 }
14296 {
14302 }
14305 {
14307 {
14310 }
14312 }
14323 {
14326 }
14336 }
14337 }
14339 /* Helper function for outputting the checksum of a tree T. When
14340 debugging with gdb, you can "define mynext" to be "next" followed
14341 by "call debug_fold_checksum (op0)", then just trace down till the
14342 outputs differ. */
14344 DEBUG_FUNCTION void
14346 {
14361 }
14363 #endif
14365 /* Fold a unary tree expression with code CODE of type TYPE with an
14366 operand OP0. LOC is the location of the resulting expression.
14367 Return a folded expression if successful. Otherwise, return a tree
14368 expression with code CODE of type TYPE with an operand OP0. */
14370 tree
14373 {
14374 tree tem;
14375 #ifdef ENABLE_FOLD_CHECKING
14384 #endif
14390 #ifdef ENABLE_FOLD_CHECKING
14397 #endif
14399 }
14401 /* Fold a binary tree expression with code CODE of type TYPE with
14402 operands OP0 and OP1. LOC is the location of the resulting
14403 expression. Return a folded expression if successful. Otherwise,
14404 return a tree expression with code CODE of type TYPE with operands
14405 OP0 and OP1. */
14407 tree
14410 MEM_STAT_DECL)
14411 {
14412 tree tem;
14413 #ifdef ENABLE_FOLD_CHECKING
14430 #endif
14436 #ifdef ENABLE_FOLD_CHECKING
14451 #endif
14453 }
14455 /* Fold a ternary tree expression with code CODE of type TYPE with
14456 operands OP0, OP1, and OP2. Return a folded expression if
14457 successful. Otherwise, return a tree expression with code CODE of
14458 type TYPE with operands OP0, OP1, and OP2. */
14460 tree
14463 {
14464 tree tem;
14465 #ifdef ENABLE_FOLD_CHECKING
14489 #endif
14496 #ifdef ENABLE_FOLD_CHECKING
14519 #endif
14521 }
14523 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
14524 arguments in ARGARRAY, and a null static chain.
14525 Return a folded expression if successful. Otherwise, return a CALL_EXPR
14526 of type TYPE from the given operands as constructed by build_call_array. */
14528 tree
14531 {
14532 tree tem;
14533 #ifdef ENABLE_FOLD_CHECKING
14552 #endif
14556 #ifdef ENABLE_FOLD_CHECKING
14572 #endif
14574 }
14576 /* Perform constant folding and related simplification of initializer
14577 expression EXPR. These behave identically to "fold_buildN" but ignore
14578 potential run-time traps and exceptions that fold must preserve. */
14580 #define START_FOLD_INIT \
14581 int saved_signaling_nans = flag_signaling_nans;\
14582 int saved_trapping_math = flag_trapping_math;\
14583 int saved_rounding_math = flag_rounding_math;\
14584 int saved_trapv = flag_trapv;\
14585 int saved_folding_initializer = folding_initializer;\
14586 flag_signaling_nans = 0;\
14587 flag_trapping_math = 0;\
14588 flag_rounding_math = 0;\
14589 flag_trapv = 0;\
14590 folding_initializer = 1;
14592 #define END_FOLD_INIT \
14593 flag_signaling_nans = saved_signaling_nans;\
14594 flag_trapping_math = saved_trapping_math;\
14595 flag_rounding_math = saved_rounding_math;\
14596 flag_trapv = saved_trapv;\
14597 folding_initializer = saved_folding_initializer;
14599 tree
14602 {
14603 tree result;
14604 START_FOLD_INIT;
14608 END_FOLD_INIT;
14610 }
14612 tree
14615 {
14616 tree result;
14617 START_FOLD_INIT;
14621 END_FOLD_INIT;
14623 }
14625 tree
14628 {
14629 tree result;
14630 START_FOLD_INIT;
14634 END_FOLD_INIT;
14636 }
14638 #undef START_FOLD_INIT
14639 #undef END_FOLD_INIT
14641 /* Determine if first argument is a multiple of second argument. Return 0 if
14642 it is not, or we cannot easily determined it to be.
14644 An example of the sort of thing we care about (at this point; this routine
14645 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14646 fold cases do now) is discovering that
14648 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14650 is a multiple of
14652 SAVE_EXPR (J * 8)
14654 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14656 This code also handles discovering that
14658 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14660 is a multiple of 8 so we don't have to worry about dealing with a
14661 possible remainder.
14663 Note that we *look* inside a SAVE_EXPR only to determine how it was
14664 calculated; it is not safe for fold to do much of anything else with the
14665 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14666 at run time. For example, the latter example above *cannot* be implemented
14667 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14668 evaluation time of the original SAVE_EXPR is not necessarily the same at
14669 the time the new expression is evaluated. The only optimization of this
14670 sort that would be valid is changing
14672 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14674 divided by 8 to
14676 SAVE_EXPR (I) * SAVE_EXPR (J)
14678 (where the same SAVE_EXPR (J) is used in the original and the
14679 transformed version). */
14681 int
14683 {
14691 {
14693 /* Bitwise and provides a power of two multiple. If the mask is
14694 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14697 /* FALLTHRU */
14710 {
14714 /* const_binop may not detect overflow correctly,
14715 so check for it explicitly here. */
14719 size_one_node,
14720 op1)))
14723 }
14727 /* Can't handle conversions from non-integral or wider integral type. */
14733 /* .. fall through ... */
14750 SIGNED);
14754 }
14755 }
14757 /* Return true if CODE or TYPE is known to be non-negative. */
14759 static bool
14761 {
14764 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14765 have a signed:1 type (where the value is -1 and 0). */
14768 }
14770 /* Return true if (CODE OP0) is known to be non-negative. If the return
14771 value is based on the assumption that signed overflow is undefined,
14772 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14773 *STRICT_OVERFLOW_P. */
14775 bool
14778 {
14783 {
14785 /* We can't return 1 if flag_wrapv is set because
14786 ABS_EXPR<INT_MIN> = INT_MIN. */
14790 {
14793 }
14800 strict_overflow_p);
14803 {
14808 {
14811 strict_overflow_p);
14813 {
14817 strict_overflow_p);
14818 }
14819 }
14821 {
14824 strict_overflow_p);
14828 }
14829 }
14834 }
14836 /* We don't know sign of `t', so be conservative and return false. */
14838 }
14840 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14841 value is based on the assumption that signed overflow is undefined,
14842 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14843 *STRICT_OVERFLOW_P. */
14845 bool
14848 {
14853 {
14858 strict_overflow_p)
14860 strict_overflow_p));
14862 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14863 both unsigned and at least 2 bits shorter than the result. */
14867 {
14872 {
14876 }
14877 }
14882 {
14883 /* x * x is always non-negative for floating point x
14884 or without overflow. */
14888 {
14892 }
14893 }
14895 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14896 both unsigned and their total bits is shorter than the result. */
14900 {
14919 {
14929 }
14930 }
14936 strict_overflow_p)
14938 strict_overflow_p));
14949 strict_overflow_p)
14951 strict_overflow_p));
14958 strict_overflow_p);
14961 }
14963 /* We don't know sign of `t', so be conservative and return false. */
14965 }
14967 /* Return true if T is known to be non-negative. If the return
14968 value is based on the assumption that signed overflow is undefined,
14969 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14970 *STRICT_OVERFLOW_P. */
14972 bool
14974 {
14979 {
14991 strict_overflow_p)
14993 strict_overflow_p));
14997 }
14998 /* We don't know sign of `t', so be conservative and return false. */
15000 }
15002 /* Return true if T is known to be non-negative. If the return
15003 value is based on the assumption that signed overflow is undefined,
15004 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15005 *STRICT_OVERFLOW_P. */
15007 bool
15010 {
15013 {
15033 /* Always true. */
15037 /* sqrt(-0.0) is -0.0. */
15041 strict_overflow_p);
15078 /* True if the 1st argument is nonnegative. */
15080 strict_overflow_p);
15083 /* True if the 1st OR 2nd arguments are nonnegative. */
15085 strict_overflow_p)
15087 strict_overflow_p)));
15090 /* True if the 1st AND 2nd arguments are nonnegative. */
15092 strict_overflow_p)
15094 strict_overflow_p)));
15097 /* True if the 2nd argument is nonnegative. */
15099 strict_overflow_p);
15102 /* True if the 1st argument is nonnegative or the second
15103 argument is an even integer. */
15108 strict_overflow_p);
15111 /* True if the 1st argument is nonnegative or the second
15112 argument is an even integer valued real. */
15114 {
15115 REAL_VALUE_TYPE c;
15116 HOST_WIDE_INT n;
15121 {
15122 REAL_VALUE_TYPE cint;
15126 }
15127 }
15129 strict_overflow_p);
15133 }
15135 type);
15136 }
15138 /* Return true if T is known to be non-negative. If the return
15139 value is based on the assumption that signed overflow is undefined,
15140 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15141 *STRICT_OVERFLOW_P. */
15143 static bool
15145 {
15151 {
15153 {
15157 /* If the initializer is non-void, then it's a normal expression
15158 that will be assigned to the slot. */
15162 /* Otherwise, the initializer sets the slot in some way. One common
15163 way is an assignment statement at the end of the initializer. */
15165 {
15173 else
15175 }
15179 strict_overflow_p);
15182 }
15185 {
15191 arg0,
15192 arg1,
15193 strict_overflow_p);
15194 }
15198 strict_overflow_p);
15201 strict_overflow_p);
15204 strict_overflow_p);
15209 }
15211 /* We don't know sign of `t', so be conservative and return false. */
15213 }
15215 /* Return true if T is known to be non-negative. If the return
15216 value is based on the assumption that signed overflow is undefined,
15217 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15218 *STRICT_OVERFLOW_P. */
15220 bool
15222 {
15229 {
15236 strict_overflow_p);
15242 strict_overflow_p);
15251 }
15254 {
15262 strict_overflow_p);
15267 strict_overflow_p);
15280 }
15281 }
15283 /* Return true if `t' is known to be non-negative. Handle warnings
15284 about undefined signed overflow. */
15286 bool
15288 {
15295 "determining that expression is always "
15297 WARN_STRICT_OVERFLOW_MISC);
15299 }
15302 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15303 For floating point we further ensure that T is not denormal.
15304 Similar logic is present in nonzero_address in rtlanal.h.
15306 If the return value is based on the assumption that signed overflow
15307 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15308 change *STRICT_OVERFLOW_P. */
15310 bool
15313 {
15315 {
15318 strict_overflow_p);
15321 {
15327 strict_overflow_p));
15328 }
15333 strict_overflow_p);
15337 }
15340 }
15342 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15343 For floating point we further ensure that T is not denormal.
15344 Similar logic is present in nonzero_address in rtlanal.h.
15346 If the return value is based on the assumption that signed overflow
15347 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15348 change *STRICT_OVERFLOW_P. */
15350 bool
15352 tree type,
15353 tree op0,
15355 {
15358 {
15362 {
15363 /* With the presence of negative values it is hard
15364 to say something. */
15371 /* One of operands must be positive and the other non-negative. */
15372 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15373 overflows, on a twos-complement machine the sum of two
15374 nonnegative numbers can never be zero. */
15376 strict_overflow_p)
15378 strict_overflow_p));
15379 }
15384 {
15386 strict_overflow_p)
15388 strict_overflow_p))
15389 {
15392 }
15393 }
15402 {
15405 }
15412 {
15416 /* When both operands are nonzero, then MAX must be too. */
15418 strict_overflow_p))
15421 /* MAX where operand 0 is positive is positive. */
15423 strict_overflow_p);
15424 }
15425 /* MAX where operand 1 is positive is positive. */
15430 {
15434 }
15439 strict_overflow_p)
15441 strict_overflow_p));
15445 }
15448 }
15450 /* Return true when T is an address and is known to be nonzero.
15451 For floating point we further ensure that T is not denormal.
15452 Similar logic is present in nonzero_address in rtlanal.h.
15454 If the return value is based on the assumption that signed overflow
15455 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15456 change *STRICT_OVERFLOW_P. */
15458 bool
15460 {
15463 {
15468 {
15477 /* For objects in symbol table check if we know they are non-zero.
15478 Don't do anything for variables and functions before symtab is built;
15479 it is quite possible that they will be declared weak later. */
15481 {
15487 else
15489 }
15491 /* Function local objects are never NULL. */
15498 /* Constants are never weak. */
15503 }
15511 {
15515 }
15520 }
15522 }
15524 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15525 attempt to fold the expression to a constant without modifying TYPE,
15526 OP0 or OP1.
15528 If the expression could be simplified to a constant, then return
15529 the constant. If the expression would not be simplified to a
15530 constant, then return NULL_TREE. */
15532 tree
15534 {
15537 }
15539 /* Given the components of a unary expression CODE, TYPE and OP0,
15540 attempt to fold the expression to a constant without modifying
15541 TYPE or OP0.
15543 If the expression could be simplified to a constant, then return
15544 the constant. If the expression would not be simplified to a
15545 constant, then return NULL_TREE. */
15547 tree
15549 {
15552 }
15554 /* If EXP represents referencing an element in a constant string
15555 (either via pointer arithmetic or array indexing), return the
15556 tree representing the value accessed, otherwise return NULL. */
15558 tree
15560 {
15564 {
15566 tree index;
15567 tree string;
15572 else
15573 {
15577 /* Optimize the special-case of a zero lower bound.
15579 We convert the low_bound to sizetype to avoid some problems
15580 with constant folding. (E.g. suppose the lower bound is 1,
15581 and its mode is QI. Without the conversion,l (ARRAY
15582 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15583 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15589 }
15602 }
15604 }
15606 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15607 an integer constant, real, or fixed-point constant.
15609 TYPE is the type of the result. */
15611 static tree
15613 {
15617 {
15619 {
15626 }
15633 {
15634 FIXED_VALUE_TYPE f;
15639 /* Propagate overflow flags. */
15643 }
15647 }
15650 }
15652 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15653 an integer constant or real constant.
15655 TYPE is the type of the result. */
15657 tree
15659 {
15663 {
15665 {
15666 /* If the value is unsigned or non-negative, then the absolute value
15667 is the same as the ordinary value. */
15671 /* If the value is negative, then the absolute value is
15672 its negation. */
15673 else
15674 {
15679 }
15680 }
15686 else
15692 }
15695 }
15697 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15698 constant. TYPE is the type of the result. */
15700 static tree
15702 {
15706 }
15708 /* Given CODE, a relational operator, the target type, TYPE and two
15709 constant operands OP0 and OP1, return the result of the
15710 relational operation. If the result is not a compile time
15711 constant, then return NULL_TREE. */
15713 static tree
15715 {
15718 /* From here on, the only cases we handle are when the result is
15719 known to be a constant. */
15722 {
15726 /* Handle the cases where either operand is a NaN. */
15728 {
15730 {
15758 }
15761 }
15764 }
15767 {
15771 }
15773 /* Handle equality/inequality of complex constants. */
15775 {
15786 else
15788 }
15791 {
15798 {
15810 }
15813 }
15815 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15817 To compute GT, swap the arguments and do LT.
15818 To compute GE, do LT and invert the result.
15819 To compute LE, swap the arguments, do LT and invert the result.
15820 To compute NE, do EQ and invert the result.
15822 Therefore, the code below must handle only EQ and LT. */
15825 {
15830 }
15832 /* Note that it is safe to invert for real values here because we
15833 have already handled the one case that it matters. */
15837 {
15840 }
15842 /* Compute a result for LT or EQ if args permit;
15843 Otherwise return T. */
15845 {
15848 else
15850 }
15851 else
15857 }
15859 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15860 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15861 itself. */
15863 tree
15865 {
15866 /* If the expression does not have side effects then we don't have to wrap
15867 it with a cleanup point expression. */
15871 /* If the expression is a return, check to see if the expression inside the
15872 return has no side effects or the right hand side of the modify expression
15873 inside the return. If either don't have side effects set we don't need to
15874 wrap the expression in a cleanup point expression. Note we don't check the
15875 left hand side of the modify because it should always be a return decl. */
15877 {
15884 }
15887 }
15889 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15890 of an indirection through OP0, or NULL_TREE if no simplification is
15891 possible. */
15893 tree
15895 {
15897 tree subtype;
15905 {
15908 /* *&CONST_DECL -> to the value of the const decl. */
15911 /* *&p => p; make sure to handle *&"str"[cst] here. */
15913 {
15917 else
15919 }
15920 /* *(foo *)&fooarray => fooarray[0] */
15923 && (!in_gimple_form
15925 {
15935 }
15936 /* *(foo *)&complexfoo => __real__ complexfoo */
15940 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15943 {
15947 }
15948 }
15952 {
15958 {
15959 tree op00type;
15963 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15966 {
15978 }
15979 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15982 {
15986 }
15987 /* ((foo *)&fooarray)[1] => fooarray[1] */
15990 {
16000 }
16001 }
16002 }
16004 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16007 && (!in_gimple_form
16009 {
16010 tree type_domain;
16020 NULL_TREE);
16021 }
16024 }
16026 /* Builds an expression for an indirection through T, simplifying some
16027 cases. */
16029 tree
16031 {
16039 }
16041 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16043 tree
16045 {
16050 else
16052 }
16054 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16055 whose result is ignored. The type of the returned tree need not be
16056 the same as the original expression. */
16058 tree
16060 {
16066 {
16077 else
16083 {
16099 }
16104 }
16105 }
16107 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16109 tree
16111 {
16117 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16118 have to do anything. Only do this when we are not given a const,
16119 because in that case, this check is more expensive than just
16120 doing it. */
16122 {
16127 }
16129 /* If divisor is a power of two, simplify this to bit manipulation. */
16131 {
16133 {
16147 }
16148 else
16149 {
16150 tree t;
16156 }
16157 }
16158 else
16159 {
16164 }
16167 }
16169 /* Likewise, but round down. */
16171 tree
16173 {
16180 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16181 have to do anything. Only do this when we are not given a const,
16182 because in that case, this check is more expensive than just
16183 doing it. */
16185 {
16190 }
16192 /* If divisor is a power of two, simplify this to bit manipulation. */
16194 {
16195 tree t;
16199 }
16200 else
16201 {
16206 }
16209 }
16211 /* Returns the pointer to the base of the object addressed by EXP and
16212 extracts the information about the offset of the access, storing it
16213 to PBITPOS and POFFSET. */
16215 static tree
16218 {
16219 tree core;
16220 machine_mode mode;
16222 HOST_WIDE_INT bitsize;
16226 {
16231 }
16232 else
16233 {
16237 }
16240 }
16242 /* Returns true if addresses of E1 and E2 differ by a constant, false
16243 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16245 bool
16247 {
16261 {
16271 }
16273 {
16274 /* If only one of the offsets is non-constant, the difference cannot
16275 be a constant. */
16277 }
16278 else
16283 }
16285 /* Simplify the floating point expression EXP when the sign of the
16286 result is not significant. Return NULL_TREE if no simplification
16287 is possible. */
16289 tree
16291 {
16296 {
16332 {
16335 {
16337 /* Strip copysign function call, return the 1st argument. */
16343 /* Strip sign ops from the argument of "odd" math functions. */
16345 {
16349 }
16351 }
16352 }
16357 }
16359 }