| blob | 553a9c37d7a46318857970828840b1b2d6bed868 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2015 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. */
78 #ifndef LOAD_EXTEND_OP
79 #define LOAD_EXTEND_OP(M) UNKNOWN
80 #endif
82 /* Nonzero if we are folding constants inside an initializer; zero
83 otherwise. */
86 /* The following constants represent a bit based encoding of GCC's
87 comparison operators. This encoding simplifies transformations
88 on relational comparison operators, such as AND and OR. */
106 };
122 HOST_WIDE_INT *,
151 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
152 Otherwise, return LOC. */
154 static location_t
156 {
159 }
161 /* Similar to protected_set_expr_location, but never modify x in place,
162 if location can and needs to be set, unshare it. */
166 {
172 {
175 }
177 }
178 \f
179 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
180 division and returns the quotient. Otherwise returns
181 NULL_TREE. */
183 tree
185 {
186 widest_int quo;
193 }
194 \f
195 /* This is nonzero if we should defer warnings about undefined
196 overflow. This facility exists because these warnings are a
197 special case. The code to estimate loop iterations does not want
198 to issue any warnings, since it works with expressions which do not
199 occur in user code. Various bits of cleanup code call fold(), but
200 only use the result if it has certain characteristics (e.g., is a
201 constant); that code only wants to issue a warning if the result is
202 used. */
206 /* If a warning about undefined overflow is deferred, this is the
207 warning. Note that this may cause us to turn two warnings into
208 one, but that is fine since it is sufficient to only give one
209 warning per expression. */
213 /* If a warning about undefined overflow is deferred, this is the
214 level at which the warning should be emitted. */
218 /* Start deferring overflow warnings. We could use a stack here to
219 permit nested calls, but at present it is not necessary. */
221 void
223 {
225 }
227 /* Stop deferring overflow warnings. If there is a pending warning,
228 and ISSUE is true, then issue the warning if appropriate. STMT is
229 the statement with which the warning should be associated (used for
230 location information); STMT may be NULL. CODE is the level of the
231 warning--a warn_strict_overflow_code value. This function will use
232 the smaller of CODE and the deferred code when deciding whether to
233 issue the warning. CODE may be zero to mean to always use the
234 deferred code. */
236 void
238 {
240 location_t locus;
245 {
251 }
262 /* Use the smallest code level when deciding to issue the
263 warning. */
272 else
275 }
277 /* Stop deferring overflow warnings, ignoring any deferred
278 warnings. */
280 void
282 {
284 }
286 /* Whether we are deferring overflow warnings. */
288 bool
290 {
292 }
294 /* This is called when we fold something based on the fact that signed
295 overflow is undefined. */
297 static void
299 {
301 {
304 {
307 }
308 }
311 }
312 \f
313 /* Return true if the built-in mathematical function specified by CODE
314 is odd, i.e. -f(x) == f(-x). */
316 bool
318 {
320 {
321 CASE_CFN_ASIN:
322 CASE_CFN_ASINH:
323 CASE_CFN_ATAN:
324 CASE_CFN_ATANH:
325 CASE_CFN_CASIN:
326 CASE_CFN_CASINH:
327 CASE_CFN_CATAN:
328 CASE_CFN_CATANH:
329 CASE_CFN_CBRT:
330 CASE_CFN_CPROJ:
331 CASE_CFN_CSIN:
332 CASE_CFN_CSINH:
333 CASE_CFN_CTAN:
334 CASE_CFN_CTANH:
335 CASE_CFN_ERF:
336 CASE_CFN_LLROUND:
337 CASE_CFN_LROUND:
338 CASE_CFN_ROUND:
339 CASE_CFN_SIN:
340 CASE_CFN_SINH:
341 CASE_CFN_TAN:
342 CASE_CFN_TANH:
343 CASE_CFN_TRUNC:
346 CASE_CFN_LLRINT:
347 CASE_CFN_LRINT:
348 CASE_CFN_NEARBYINT:
349 CASE_CFN_RINT:
354 }
356 }
358 /* Check whether we may negate an integer constant T without causing
359 overflow. */
361 bool
363 {
364 tree type;
373 }
375 /* Determine whether an expression T can be cheaply negated using
376 the function negate_expr without introducing undefined overflow. */
378 static bool
380 {
381 tree type;
390 {
395 /* Check that -CST will not overflow type. */
408 /* We want to canonicalize to positive real constants. Pretend
409 that only negative ones can be easily negated. */
417 {
428 }
443 /* -(A + B) -> (-B) - A. */
448 /* -(A + B) -> (-A) - B. */
452 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
463 /* INT_MIN/n * n doesn't overflow while negating one operand it does
464 if n is a power of two. */
473 /* Fall through. */
488 /* In general we can't negate B in A / B, because if A is INT_MIN and
489 B is 1, we may turn this into INT_MIN / -1 which is undefined
490 and actually traps on some architectures. */
499 /* Negate -((double)float) as (double)(-float). */
501 {
505 }
509 /* Negate -f(x) as f(-x). */
515 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
517 {
521 }
526 }
528 }
530 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
531 simplification is possible.
532 If negate_expr_p would return true for T, NULL_TREE will never be
533 returned. */
535 static tree
537 {
539 tree tem;
542 {
543 /* Convert - (~A) to A + 1. */
569 {
574 }
578 {
583 {
587 }
590 }
613 {
614 /* -(A + B) -> (-B) - A. */
618 {
622 }
624 /* -(A + B) -> (-A) - B. */
626 {
630 }
631 }
635 /* - (A - B) -> B - A */
647 /* Fall through. */
651 {
660 }
672 /* In general we can't negate B in A / B, because if A is INT_MIN and
673 B is 1, we may turn this into INT_MIN / -1 which is undefined
674 and actually traps on some architectures. */
686 /* Convert -((double)float) into (double)(-float). */
688 {
692 }
696 /* Negate -f(x) as f(-x). */
699 {
705 }
709 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
711 {
714 {
721 }
722 }
727 }
730 }
732 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
733 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
734 return NULL_TREE. */
736 static tree
738 {
740 location_t loc;
753 }
754 \f
755 /* Split a tree IN into a constant, literal and variable parts that could be
756 combined with CODE to make IN. "constant" means an expression with
757 TREE_CONSTANT but that isn't an actual constant. CODE must be a
758 commutative arithmetic operation. Store the constant part into *CONP,
759 the literal in *LITP and return the variable part. If a part isn't
760 present, set it to null. If the tree does not decompose in this way,
761 return the entire tree as the variable part and the other parts as null.
763 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
764 case, we negate an operand that was subtracted. Except if it is a
765 literal for which we use *MINUS_LITP instead.
767 If NEGATE_P is true, we are negating all of IN, again except a literal
768 for which we use *MINUS_LITP instead.
770 If IN is itself a literal or constant, return it as appropriate.
772 Note that we do not guarantee that any of the three values will be the
773 same type as IN, but they will have the same signedness and mode. */
775 static tree
778 {
785 /* Strip any conversions that don't change the machine mode or signedness. */
794 /* We can associate addition and subtraction together (even
795 though the C standard doesn't say so) for integers because
796 the value is not affected. For reals, the value might be
797 affected, so we can't. */
800 {
806 /* First see if either of the operands is a literal, then a constant. */
819 /* If we haven't dealt with either operand, this is not a case we can
820 decompose. Otherwise, VAR is either of the ones remaining, if any. */
825 else
828 /* Now do any needed negations. */
835 }
838 {
839 /* -X - 1 is folded to ~X, undo that here. */
842 }
845 else
849 {
856 }
859 }
861 /* Re-associate trees split by the above function. T1 and T2 are
862 either expressions to associate or null. Return the new
863 expression, if any. LOC is the location of the new expression. If
864 we build an operation, do it in TYPE and with CODE. */
866 static tree
868 {
874 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
875 try to fold this since we will have infinite recursion. But do
876 deal with any NEGATE_EXPRs. */
879 {
881 {
894 }
896 {
899 }
903 }
907 }
908 \f
909 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
910 for use in int_const_binop, size_binop and size_diffop. */
912 static bool
914 {
921 {
930 }
935 }
938 /* Combine two integer constants ARG1 and ARG2 under operation CODE
939 to produce a new constant. Return NULL_TREE if we don't know how
940 to evaluate CODE at compile-time. */
942 static tree
945 {
946 wide_int res;
947 tree t;
956 {
972 {
976 else
978 }
981 /* It's unclear from the C standard whether shifts can overflow.
982 The following code ignores overflow; perhaps a C standard
983 interpretation ruling is needed. */
985 else
992 {
996 else
998 }
1002 else
1081 }
1089 }
1091 tree
1093 {
1095 }
1097 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1098 constant. We assume ARG1 and ARG2 have the same data type, or at least
1099 are the same kind of constant and the same machine mode. Return zero if
1100 combining the constants is not allowed in the current operating mode. */
1102 static tree
1104 {
1105 /* Sanity check for the recursive cases. */
1113 {
1119 }
1122 {
1123 machine_mode mode;
1124 REAL_VALUE_TYPE d1;
1125 REAL_VALUE_TYPE d2;
1126 REAL_VALUE_TYPE value;
1127 REAL_VALUE_TYPE result;
1131 /* The following codes are handled by real_arithmetic. */
1133 {
1144 }
1152 /* Don't perform operation if we honor signaling NaNs and
1153 either operand is a NaN. */
1158 /* Don't perform operation if it would raise a division
1159 by zero exception. */
1165 /* If either operand is a NaN, just return it. Otherwise, set up
1166 for floating-point trap; we return an overflow. */
1175 /* Don't constant fold this floating point operation if
1176 the result has overflowed and flag_trapping_math. */
1184 /* Don't constant fold this floating point operation if the
1185 result may dependent upon the run-time rounding mode and
1186 flag_rounding_math is set, or if GCC's software emulation
1187 is unable to accurately represent the result. */
1197 }
1200 {
1201 FIXED_VALUE_TYPE f1;
1202 FIXED_VALUE_TYPE f2;
1203 FIXED_VALUE_TYPE result;
1208 /* The following codes are handled by fixed_arithmetic. */
1210 {
1222 {
1229 }
1234 }
1241 /* Propagate overflow flags. */
1245 }
1248 {
1257 {
1268 mpc_mul);
1282 mpc_div);
1283 /* Fallthru ... */
1289 {
1290 /* Keep this algorithm in sync with
1291 tree-complex.c:expand_complex_div_straight().
1293 Expand complex division to scalars, straightforward algorithm.
1294 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1295 t = br*br + bi*bi
1296 */
1297 tree magsquared
1301 tree t1
1305 tree t2
1312 }
1313 else
1314 {
1315 /* Keep this algorithm in sync with
1316 tree-complex.c:expand_complex_div_wide().
1318 Expand complex division to scalars, modified algorithm to minimize
1319 overflow with wide input ranges. */
1325 {
1326 /* In the TRUE branch, we compute
1327 ratio = br/bi;
1328 div = (br * ratio) + bi;
1329 tr = (ar * ratio) + ai;
1330 ti = (ai * ratio) - ar;
1331 tr = tr / div;
1332 ti = ti / div; */
1343 }
1344 else
1345 {
1346 /* In the FALSE branch, we compute
1347 ratio = d/c;
1348 divisor = (d * ratio) + c;
1349 tr = (b * ratio) + a;
1350 ti = b - (a * ratio);
1351 tr = tr / div;
1352 ti = ti / div; */
1364 }
1365 }
1370 }
1374 }
1378 {
1384 {
1390 /* It is possible that const_binop cannot handle the given
1391 code and return NULL_TREE */
1394 }
1397 }
1399 /* Shifts allow a scalar offset for a vector. */
1402 {
1408 {
1413 /* It is possible that const_binop cannot handle the given
1414 code and return NULL_TREE. */
1417 }
1420 }
1422 }
1424 /* Overload that adds a TYPE parameter to be able to dispatch
1425 to fold_relational_const. */
1427 tree
1429 {
1433 /* ??? Until we make the const_binop worker take the type of the
1434 result as argument put those cases that need it here. */
1436 {
1447 {
1463 {
1469 }
1472 }
1478 {
1503 {
1516 }
1519 }
1522 }
1527 /* Make sure type and arg0 have the same saturating flag. */
1532 }
1534 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1535 Return zero if computing the constants is not possible. */
1537 tree
1539 {
1541 {
1542 CASE_CONVERT:
1549 /* If the source address is 0, and the source address space
1550 cannot have a valid object at 0, fold to dest type null. */
1561 {
1562 /* Can't call fold_negate_const directly here as that doesn't
1563 handle all cases and we might not be able to negate some
1564 constants. */
1569 }
1578 {
1582 }
1588 /* Perform BIT_NOT_EXPR on each element individually. */
1590 {
1592 tree elem;
1597 {
1603 }
1606 }
1628 {
1647 else
1651 {
1655 }
1658 }
1663 {
1677 {
1682 }
1685 {
1689 }
1692 }
1696 }
1699 }
1701 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1702 indicates which particular sizetype to create. */
1704 tree
1706 {
1708 }
1709 \f
1710 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1711 is a tree code. The type of the result is taken from the operands.
1712 Both must be equivalent integer types, ala int_binop_types_match_p.
1713 If the operands are constant, so is the result. */
1715 tree
1717 {
1726 /* Handle the special case of two integer constants faster. */
1728 {
1729 /* And some specific cases even faster than that. */
1731 {
1736 }
1738 {
1741 }
1743 {
1746 }
1748 /* Handle general case of two integer constants. For sizetype
1749 constant calculations we always want to know about overflow,
1750 even in the unsigned case. */
1752 }
1755 }
1757 /* Given two values, either both of sizetype or both of bitsizetype,
1758 compute the difference between the two values. Return the value
1759 in signed type corresponding to the type of the operands. */
1761 tree
1763 {
1765 tree ctype;
1770 /* If the type is already signed, just do the simple thing. */
1778 else
1781 /* If either operand is not a constant, do the conversions to the signed
1782 type and subtract. The hardware will do the right thing with any
1783 overflow in the subtraction. */
1789 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1790 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1791 overflow) and negate (which can't either). Special-case a result
1792 of zero while we're here. */
1798 else
1802 MINUS_EXPR,
1804 }
1805 \f
1806 /* A subroutine of fold_convert_const handling conversions of an
1807 INTEGER_CST to another integer type. */
1809 static tree
1811 {
1812 /* Given an integer constant, make new constant with new type,
1813 appropriately sign-extended or truncated. Use widest_int
1814 so that any extension is done according ARG1's type. */
1818 }
1820 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1821 to an integer type. */
1823 static tree
1825 {
1827 tree t;
1829 /* The following code implements the floating point to integer
1830 conversion rules required by the Java Language Specification,
1831 that IEEE NaNs are mapped to zero and values that overflow
1832 the target precision saturate, i.e. values greater than
1833 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1834 are mapped to INT_MIN. These semantics are allowed by the
1835 C and C++ standards that simply state that the behavior of
1836 FP-to-integer conversion is unspecified upon overflow. */
1838 wide_int val;
1839 REAL_VALUE_TYPE r;
1843 {
1850 }
1852 /* If R is NaN, return zero and show we have an overflow. */
1854 {
1857 }
1859 /* See if R is less than the lower bound or greater than the
1860 upper bound. */
1863 {
1867 {
1870 }
1871 }
1874 {
1877 {
1880 {
1883 }
1884 }
1885 }
1892 }
1894 /* A subroutine of fold_convert_const handling conversions of a
1895 FIXED_CST to an integer type. */
1897 static tree
1899 {
1900 tree t;
1904 /* Right shift FIXED_CST to temp by fbit. */
1908 {
1910 HOST_BITS_PER_DOUBLE_INT,
1913 /* Left shift temp to temp_trunc by fbit. */
1915 HOST_BITS_PER_DOUBLE_INT,
1917 }
1918 else
1919 {
1922 }
1924 /* If FIXED_CST is negative, we need to round the value toward 0.
1925 By checking if the fractional bits are not zero to add 1 to temp. */
1931 /* Given a fixed-point constant, make new constant with new type,
1932 appropriately sign-extended or truncated. */
1940 }
1942 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1943 to another floating point type. */
1945 static tree
1947 {
1948 REAL_VALUE_TYPE value;
1949 tree t;
1954 /* If converting an infinity or NAN to a representation that doesn't
1955 have one, set the overflow bit so that we can produce some kind of
1956 error message at the appropriate point if necessary. It's not the
1957 most user-friendly message, but it's better than nothing. */
1964 /* Regular overflow, conversion produced an infinity in a mode that
1965 can't represent them. */
1970 else
1973 }
1975 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1976 to a floating point type. */
1978 static tree
1980 {
1981 REAL_VALUE_TYPE value;
1982 tree t;
1989 }
1991 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
1992 to another fixed-point type. */
1994 static tree
1996 {
1997 FIXED_VALUE_TYPE value;
1998 tree t;
2005 /* Propagate overflow flags. */
2009 }
2011 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2012 to a fixed-point type. */
2014 static tree
2016 {
2017 FIXED_VALUE_TYPE value;
2018 tree t;
2020 double_int di;
2027 else
2035 /* Propagate overflow flags. */
2039 }
2041 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2042 to a fixed-point type. */
2044 static tree
2046 {
2047 FIXED_VALUE_TYPE value;
2048 tree t;
2056 /* Propagate overflow flags. */
2060 }
2062 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2063 type TYPE. If no simplification can be done return NULL_TREE. */
2065 static tree
2067 {
2073 {
2080 }
2082 {
2089 }
2091 {
2098 }
2100 {
2103 {
2108 {
2114 }
2116 }
2117 }
2119 }
2121 /* Construct a vector of zero elements of vector type TYPE. */
2123 static tree
2125 {
2126 tree t;
2130 }
2132 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2134 bool
2136 {
2151 {
2170 }
2171 }
2173 /* Convert expression ARG to type TYPE. Used by the middle-end for
2174 simple conversions in preference to calling the front-end's convert. */
2176 tree
2178 {
2180 tree tem;
2191 {
2194 /* Handle conversions between pointers to different address spaces. */
2199 /* fall through */
2204 {
2208 }
2222 {
2226 }
2228 {
2232 }
2234 {
2238 }
2241 {
2259 }
2264 {
2268 }
2271 {
2285 }
2289 {
2298 integer_zero_node));
2300 {
2304 {
2310 }
2318 }
2322 }
2340 }
2341 fold_convert_exit:
2344 }
2345 \f
2346 /* Return false if expr can be assumed not to be an lvalue, true
2347 otherwise. */
2349 static bool
2351 {
2352 /* We only need to wrap lvalue tree codes. */
2354 {
2385 /* Assume the worst for front-end tree codes. */
2389 }
2392 }
2394 /* Return an expr equal to X but certainly not valid as an lvalue. */
2396 tree
2398 {
2399 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2400 us. */
2407 }
2409 /* When pedantic, return an expr equal to X but certainly not valid as a
2410 pedantic lvalue. Otherwise, return X. */
2412 static tree
2414 {
2416 }
2417 \f
2418 /* Given a tree comparison code, return the code that is the logical inverse.
2419 It is generally not safe to do this for floating-point comparisons, except
2420 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2421 ERROR_MARK in this case. */
2423 enum tree_code
2425 {
2431 {
2462 }
2463 }
2465 /* Similar, but return the comparison that results if the operands are
2466 swapped. This is safe for floating-point. */
2468 enum tree_code
2470 {
2472 {
2498 }
2499 }
2502 /* Convert a comparison tree code from an enum tree_code representation
2503 into a compcode bit-based encoding. This function is the inverse of
2504 compcode_to_comparison. */
2506 static enum comparison_code
2508 {
2510 {
2541 }
2542 }
2544 /* Convert a compcode bit-based encoding of a comparison operator back
2545 to GCC's enum tree_code representation. This function is the
2546 inverse of comparison_to_compcode. */
2548 static enum tree_code
2550 {
2552 {
2583 }
2584 }
2586 /* Return a tree for the comparison which is the combination of
2587 doing the AND or OR (depending on CODE) of the two operations LCODE
2588 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2589 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2590 if this makes the transformation invalid. */
2592 tree
2597 {
2604 {
2615 }
2618 {
2619 /* Eliminate unordered comparisons, as well as LTGT and ORD
2620 which are not used unless the mode has NaNs. */
2626 }
2628 {
2629 /* Check that the original operation and the optimized ones will trap
2630 under the same condition. */
2641 /* In a short-circuited boolean expression the LHS might be
2642 such that the RHS, if evaluated, will never trap. For
2643 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2644 if neither x nor y is NaN. (This is a mixed blessing: for
2645 example, the expression above will never trap, hence
2646 optimizing it to x < y would be invalid). */
2651 /* If the comparison was short-circuited, and only the RHS
2652 trapped, we may now generate a spurious trap. */
2657 /* If we changed the conditions that cause a trap, we lose. */
2660 }
2666 else
2667 {
2672 }
2673 }
2674 \f
2675 /* Return nonzero if two operands (typically of the same tree node)
2676 are necessarily equal. FLAGS modifies behavior as follows:
2678 If OEP_ONLY_CONST is set, only return nonzero for constants.
2679 This function tests whether the operands are indistinguishable;
2680 it does not test whether they are equal using C's == operation.
2681 The distinction is important for IEEE floating point, because
2682 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2683 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2685 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2686 even though it may hold multiple values during a function.
2687 This is because a GCC tree node guarantees that nothing else is
2688 executed between the evaluation of its "operands" (which may often
2689 be evaluated in arbitrary order). Hence if the operands themselves
2690 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2691 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2692 unset means assuming isochronic (or instantaneous) tree equivalence.
2693 Unless comparing arbitrary expression trees, such as from different
2694 statements, this flag can usually be left unset.
2696 If OEP_PURE_SAME is set, then pure functions with identical arguments
2697 are considered the same. It is used when the caller has other ways
2698 to ensure that global memory is unchanged in between.
2700 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2701 not values of expressions.
2703 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2704 any operand with side effect. This is unnecesarily conservative in the
2705 case we know that arg0 and arg1 are in disjoint code paths (such as in
2706 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2707 addresses with TREE_CONSTANT flag set so we know that &var == &var
2708 even if var is volatile. */
2710 int
2712 {
2713 /* If either is ERROR_MARK, they aren't equal. */
2719 /* Similar, if either does not have a type (like a released SSA name),
2720 they aren't equal. */
2724 /* We cannot consider pointers to different address space equal. */
2731 /* Check equality of integer constants before bailing out due to
2732 precision differences. */
2734 {
2735 /* Address of INTEGER_CST is not defined; check that we did not forget
2736 to drop the OEP_ADDRESS_OF flags. */
2739 }
2742 {
2743 /* If both types don't have the same signedness, then we can't consider
2744 them equal. We must check this before the STRIP_NOPS calls
2745 because they may change the signedness of the arguments. As pointers
2746 strictly don't have a signedness, require either two pointers or
2747 two non-pointers as well. */
2753 /* If both types don't have the same precision, then it is not safe
2754 to strip NOPs. */
2761 }
2762 #if 0
2763 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2764 sanity check once the issue is solved. */
2765 else
2766 /* Addresses of conversions and SSA_NAMEs (and many other things)
2767 are not defined. Check that we did not forget to drop the
2768 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2771 #endif
2773 /* In case both args are comparisons but with different comparison
2774 code, try to swap the comparison operands of one arg to produce
2775 a match and compare that variant. */
2779 {
2787 }
2790 {
2791 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2793 ;
2795 {
2796 /* If we are interested in comparing addresses ignore
2797 MEM_REF wrappings of the base that can appear just for
2798 TBAA reasons. */
2812 }
2813 else
2815 }
2817 /* When not checking adddresses, this is needed for conversions and for
2818 COMPONENT_REF. Might as well play it safe and always test this. */
2825 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2826 We don't care about side effects in that case because the SAVE_EXPR
2827 takes care of that for us. In all other cases, two expressions are
2828 equal if they have no side effects. If we have two identical
2829 expressions with side effects that should be treated the same due
2830 to the only side effects being identical SAVE_EXPR's, that will
2831 be detected in the recursive calls below.
2832 If we are taking an invariant address of two identical objects
2833 they are necessarily equal as well. */
2840 /* Next handle constant cases, those for which we can return 1 even
2841 if ONLY_CONST is set. */
2844 {
2858 {
2859 /* If we do not distinguish between signed and unsigned zero,
2860 consider them equal. */
2863 }
2867 {
2874 {
2878 }
2880 }
2884 flags)
2886 flags));
2897 flags | OEP_ADDRESS_OF
2900 /* In GIMPLE empty constructors are allowed in initializers of
2901 aggregates. */
2906 }
2911 /* Define macros to test an operand from arg0 and arg1 for equality and a
2912 variant that allows null and views null as being different from any
2913 non-null value. In the latter case, if either is null, the both
2914 must be; otherwise, do the normal comparison. */
2915 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2916 TREE_OPERAND (arg1, N), flags)
2918 #define OP_SAME_WITH_NULL(N) \
2919 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2920 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2923 {
2925 /* Two conversions are equal only if signedness and modes match. */
2927 {
2928 CASE_CONVERT:
2936 }
2946 /* For commutative ops, allow the other order. */
2954 /* If either of the pointer (or reference) expressions we are
2955 dereferencing contain a side effect, these cannot be equal,
2956 but their addresses can be. */
2963 {
2980 {
2981 /* Require equal access sizes */
2987 flags)))
2989 /* Verify that accesses are TBAA compatible. */
2998 /* Verify that alignment is compatible. */
3002 }
3005 /* TARGET_MEM_REF require equal extra operands. */
3013 /* Operands 2 and 3 may be null.
3014 Compare the array index by value if it is constant first as we
3015 may have different types but same value here. */
3026 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3027 may be NULL when we're called to compare MEM_EXPRs. */
3042 }
3046 {
3048 /* Be sure we pass right ADDRESS_OF flag. */
3066 /* The multiplcation operands are commutative. */
3067 /* FALLTHRU */
3075 /* Otherwise take into account this is a commutative operation. */
3088 }
3092 {
3096 /* If not both CALL_EXPRs are either internal or normal function
3097 functions, then they are not equal. */
3100 {
3101 /* If the CALL_EXPRs call different internal functions, then they
3102 are not equal. */
3105 }
3106 else
3107 {
3108 /* If the CALL_EXPRs call different functions, then they are not
3109 equal. */
3111 flags))
3113 }
3115 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3116 {
3120 else
3124 }
3126 /* Now see if all the arguments are the same. */
3127 {
3138 /* If we get here and both argument lists are exhausted
3139 then the CALL_EXPRs are equal. */
3141 }
3144 }
3147 /* Consider __builtin_sqrt equal to sqrt. */
3155 {
3156 /* In GIMPLE constructors are used only to build vectors from
3157 elements. Individual elements in the constructor must be
3158 indexed in increasing order and form an initial sequence.
3160 We make no effort to compare constructors in generic.
3161 (see sem_variable::equals in ipa-icf which can do so for
3162 constants). */
3167 /* Be sure that vectors constructed have the same representation.
3168 We only tested element precision and modes to match.
3169 Vectors may be BLKmode and thus also check that the number of
3170 parts match. */
3183 {
3188 /* In GIMPLE the indexes can be either NULL or matching i.
3189 Double check this so we won't get false
3190 positives for GENERIC. */
3198 }
3200 }
3205 }
3207 #undef OP_SAME
3208 #undef OP_SAME_WITH_NULL
3209 }
3210 \f
3211 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3212 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3214 When in doubt, return 0. */
3216 static int
3218 {
3230 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3231 and see if the inner values are the same. This removes any
3232 signedness comparison, which doesn't matter here. */
3239 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3240 actual comparison operand, ARG0.
3242 First throw away any conversions to wider types
3243 already present in the operands. */
3252 {
3255 /* Make sure shorter operand is extended the right way
3256 to match the longer operand. */
3262 }
3265 }
3266 \f
3267 /* See if ARG is an expression that is either a comparison or is performing
3268 arithmetic on comparisons. The comparisons must only be comparing
3269 two different values, which will be stored in *CVAL1 and *CVAL2; if
3270 they are nonzero it means that some operands have already been found.
3271 No variables may be used anywhere else in the expression except in the
3272 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3273 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3275 If this is true, return 1. Otherwise, return zero. */
3277 static int
3279 {
3283 /* We can handle some of the tcc_expression cases here. */
3293 {
3294 /* If we've already found a CVAL1 or CVAL2, this expression is
3295 two complex to handle. */
3301 }
3304 {
3327 /* First see if we can handle the first operand, then the second. For
3328 the second operand, we know *CVAL1 can't be zero. It must be that
3329 one side of the comparison is each of the values; test for the
3330 case where this isn't true by failing if the two operands
3331 are the same. */
3340 ;
3344 ;
3345 else
3349 ;
3353 ;
3354 else
3361 }
3362 }
3363 \f
3364 /* ARG is a tree that is known to contain just arithmetic operations and
3365 comparisons. Evaluate the operations in the tree substituting NEW0 for
3366 any occurrence of OLD0 as an operand of a comparison and likewise for
3367 NEW1 and OLD1. */
3369 static tree
3372 {
3377 /* We can handle some of the tcc_expression cases here. */
3385 {
3400 {
3419 }
3420 /* Fall through - ??? */
3423 {
3427 /* We need to check both for exact equality and tree equality. The
3428 former will be true if the operand has a side-effect. In that
3429 case, we know the operand occurred exactly once. */
3442 }
3446 }
3447 }
3448 \f
3449 /* Return a tree for the case when the result of an expression is RESULT
3450 converted to TYPE and OMITTED was previously an operand of the expression
3451 but is now not needed (e.g., we folded OMITTED * 0).
3453 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3454 the conversion of RESULT to TYPE. */
3456 tree
3458 {
3461 /* If the resulting operand is an empty statement, just return the omitted
3462 statement casted to void. */
3472 }
3474 /* Return a tree for the case when the result of an expression is RESULT
3475 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3476 of the expression but are now not needed.
3478 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3479 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3480 evaluated before OMITTED2. Otherwise, if neither has side effects,
3481 just do the conversion of RESULT to TYPE. */
3483 tree
3486 {
3495 }
3497 \f
3498 /* Return a simplified tree node for the truth-negation of ARG. This
3499 never alters ARG itself. We assume that ARG is an operation that
3500 returns a truth value (0 or 1).
3502 FIXME: one would think we would fold the result, but it causes
3503 problems with the dominator optimizer. */
3505 static tree
3507 {
3512 /* If this is a comparison, we can simply invert it, except for
3513 floating-point non-equality comparisons, in which case we just
3514 enclose a TRUTH_NOT_EXPR around what we have. */
3517 {
3520 && flag_trapping_math
3531 }
3534 {
3553 /* Here we can invert either operand. We invert the first operand
3554 unless the second operand is a TRUTH_NOT_EXPR in which case our
3555 result is the XOR of the first operand with the inside of the
3556 negation of the second operand. */
3561 else
3584 {
3591 /* A COND_EXPR may have a throw as one operand, which
3592 then has void type. Just leave void operands
3593 as they are. */
3599 }
3611 CASE_CONVERT:
3615 /* ... fall through ... */
3637 }
3638 }
3640 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3641 assume that ARG is an operation that returns a truth value (0 or 1
3642 for scalars, 0 or -1 for vectors). Return the folded expression if
3643 folding is successful. Otherwise, return NULL_TREE. */
3645 static tree
3647 {
3650 ? BIT_NOT_EXPR
3653 }
3655 /* Return a simplified tree node for the truth-negation of ARG. This
3656 never alters ARG itself. We assume that ARG is an operation that
3657 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3659 tree
3661 {
3667 ? BIT_NOT_EXPR
3670 }
3672 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3673 with code CODE. This optimization is unsafe. */
3674 static tree
3677 {
3681 /* (A / C) +- (B / C) -> (A +- B) / C. */
3691 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3696 {
3708 }
3711 }
3712 \f
3713 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3714 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3715 and uses reverse storage order if REVERSEP is nonzero. */
3717 static tree
3721 {
3725 {
3732 }
3747 }
3749 /* Optimize a bit-field compare.
3751 There are two cases: First is a compare against a constant and the
3752 second is a comparison of two items where the fields are at the same
3753 bit position relative to the start of a chunk (byte, halfword, word)
3754 large enough to contain it. In these cases we can avoid the shift
3755 implicit in bitfield extractions.
3757 For constants, we emit a compare of the shifted constant with the
3758 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3759 compared. For two fields at the same position, we do the ANDs with the
3760 similar mask and compare the result of the ANDs.
3762 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3763 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3764 are the left and right operands of the comparison, respectively.
3766 If the optimization described above can be done, we return the resulting
3767 tree. Otherwise we return zero. */
3769 static tree
3772 {
3775 tree unsigned_type;
3782 tree mask;
3783 tree offset;
3785 /* Get all the information about the extractions being done. If the bit size
3786 if the same as the size of the underlying object, we aren't doing an
3787 extraction at all and so can do nothing. We also don't want to
3788 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3789 then will no longer be able to replace it. */
3798 else
3799 {
3800 /* If this is not a constant, we can only do something if bit positions,
3801 sizes, signedness and storage order are the same. */
3802 rinner
3810 }
3812 /* See if we can find a mode to refer to this field. We should be able to,
3813 but fail if we can't. */
3822 /* Set signed and unsigned types of the precision of this mode for the
3823 shifts below. */
3826 /* Compute the bit position and size for the new reference and our offset
3827 within it. If the new reference is the same size as the original, we
3828 won't optimize anything, so return zero. */
3838 /* Make the mask to be used against the extracted field. */
3845 /* If not comparing with constant, just rework the comparison
3846 and return. */
3850 unsigned_type,
3853 mask),
3856 unsigned_type,
3859 mask));
3861 /* Otherwise, we are handling the constant case. See if the constant is too
3862 big for the field. Warn and return a tree for 0 (false) if so. We do
3863 this not only for its own sake, but to avoid having to test for this
3864 error case below. If we didn't, we might generate wrong code.
3866 For unsigned fields, the constant shifted right by the field length should
3867 be all zero. For signed fields, the high-order bits should agree with
3868 the sign bit. */
3871 {
3873 {
3877 }
3878 }
3879 else
3880 {
3883 {
3887 }
3888 }
3890 /* Single-bit compares should always be against zero. */
3892 {
3895 }
3897 /* Make a new bitfield reference, shift the constant over the
3898 appropriate number of bits and mask it with the computed mask
3899 (in case this was a signed field). If we changed it, make a new one. */
3901 lreversep);
3907 mask);
3912 }
3913 \f
3914 /* Subroutine for fold_truth_andor_1: decode a field reference.
3916 If EXP is a comparison reference, we return the innermost reference.
3918 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3919 set to the starting bit number.
3921 If the innermost field can be completely contained in a mode-sized
3922 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3924 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3925 otherwise it is not changed.
3927 *PUNSIGNEDP is set to the signedness of the field.
3929 *PREVERSEP is set to the storage order of the field.
3931 *PMASK is set to the mask used. This is either contained in a
3932 BIT_AND_EXPR or derived from the width of the field.
3934 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3936 Return 0 if this is not a component reference or is one that we can't
3937 do anything with. */
3939 static tree
3944 {
3948 tree unsigned_type;
3951 /* All the optimizations using this function assume integer fields.
3952 There are problems with FP fields since the type_for_size call
3953 below can fail for, e.g., XFmode. */
3957 /* We are interested in the bare arrangement of bits, so strip everything
3958 that doesn't affect the machine mode. However, record the type of the
3959 outermost expression if it may matter below. */
3966 {
3972 }
3981 /* If the number of bits in the reference is the same as the bitsize of
3982 the outer type, then the outer type gives the signedness. Otherwise
3983 (in case of a small bitfield) the signedness is unchanged. */
3987 /* Compute the mask to access the bitfield. */
3996 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4004 }
4006 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4007 bit positions and MASK is SIGNED. */
4009 static int
4011 {
4015 /* If this function returns true when the type of the mask is
4016 UNSIGNED, then there will be errors. In particular see
4017 gcc.c-torture/execute/990326-1.c. There does not appear to be
4018 any documentation paper trail as to why this is so. But the pre
4019 wide-int worked with that restriction and it has been preserved
4020 here. */
4025 }
4027 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4028 represents the sign bit of EXP's type. If EXP represents a sign
4029 or zero extension, also test VAL against the unextended type.
4030 The return value is the (sub)expression whose sign bit is VAL,
4031 or NULL_TREE otherwise. */
4033 tree
4035 {
4037 tree t;
4039 /* Tree EXP must have an integral type. */
4044 /* Tree VAL must be an integer constant. */
4053 /* Handle extension from a narrower type. */
4059 }
4061 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4062 to be evaluated unconditionally. */
4064 static int
4066 {
4067 /* Strip any conversions that don't change the machine mode. */
4076 /* Don't regard global variables as simple. They may be
4077 allocated in ways unknown to the compiler (shared memory,
4078 #pragma weak, etc). */
4081 /* Weakrefs are not safe to be read, since they can be NULL.
4082 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4083 have DECL_WEAK flag set. */
4085 /* Loading a static variable is unduly expensive, but global
4086 registers aren't expensive. */
4088 }
4090 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4091 to be evaluated unconditionally.
4092 I addition to simple_operand_p, we assume that comparisons, conversions,
4093 and logic-not operations are simple, if their operands are simple, too. */
4095 static bool
4097 {
4117 }
4119 \f
4120 /* The following functions are subroutines to fold_range_test and allow it to
4121 try to change a logical combination of comparisons into a range test.
4123 For example, both
4124 X == 2 || X == 3 || X == 4 || X == 5
4125 and
4126 X >= 2 && X <= 5
4127 are converted to
4128 (unsigned) (X - 2) <= 3
4130 We describe each set of comparisons as being either inside or outside
4131 a range, using a variable named like IN_P, and then describe the
4132 range with a lower and upper bound. If one of the bounds is omitted,
4133 it represents either the highest or lowest value of the type.
4135 In the comments below, we represent a range by two numbers in brackets
4136 preceded by a "+" to designate being inside that range, or a "-" to
4137 designate being outside that range, so the condition can be inverted by
4138 flipping the prefix. An omitted bound is represented by a "-". For
4139 example, "- [-, 10]" means being outside the range starting at the lowest
4140 possible value and ending at 10, in other words, being greater than 10.
4141 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4142 always false.
4144 We set up things so that the missing bounds are handled in a consistent
4145 manner so neither a missing bound nor "true" and "false" need to be
4146 handled using a special case. */
4148 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4149 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4150 and UPPER1_P are nonzero if the respective argument is an upper bound
4151 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4152 must be specified for a comparison. ARG1 will be converted to ARG0's
4153 type if both are specified. */
4155 static tree
4158 {
4159 tree tem;
4163 /* If neither arg represents infinity, do the normal operation.
4164 Else, if not a comparison, return infinity. Else handle the special
4165 comparison rules. Note that most of the cases below won't occur, but
4166 are handled for consistency. */
4169 {
4174 }
4179 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4180 for neither. In real maths, we cannot assume open ended ranges are
4181 the same. But, this is computer arithmetic, where numbers are finite.
4182 We can therefore make the transformation of any unbounded range with
4183 the value Z, Z being greater than any representable number. This permits
4184 us to treat unbounded ranges as equal. */
4188 {
4209 }
4212 }
4213 \f
4214 /* Helper routine for make_range. Perform one step for it, return
4215 new expression if the loop should continue or NULL_TREE if it should
4216 stop. */
4218 tree
4222 {
4228 {
4230 /* We can only do something if the range is testing for zero. */
4239 /* We can only do something if the range is testing for zero
4240 and if the second operand is an integer constant. Note that
4241 saying something is "in" the range we make is done by
4242 complementing IN_P since it will set in the initial case of
4243 being not equal to zero; "out" is leaving it alone. */
4250 {
4271 }
4273 /* If this is an unsigned comparison, we also know that EXP is
4274 greater than or equal to zero. We base the range tests we make
4275 on that fact, so we record it here so we can parse existing
4276 range tests. We test arg0_type since often the return type
4277 of, e.g. EQ_EXPR, is boolean. */
4279 {
4283 NULL_TREE))
4288 /* If the high bound is missing, but we have a nonzero low
4289 bound, reverse the range so it goes from zero to the low bound
4290 minus 1. */
4292 {
4297 }
4298 }
4306 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4307 low and high are non-NULL, then normalize will DTRT. */
4310 {
4315 }
4317 /* (-x) IN [a,b] -> x in [-b, -a] */
4329 /* ~ X -> -X - 1 */
4338 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4339 move a constant to the other side. */
4344 /* If EXP is signed, any overflow in the computation is undefined,
4345 so we don't worry about it so long as our computations on
4346 the bounds don't overflow. For unsigned, overflow is defined
4347 and this is exactly the right thing. */
4359 normalize:
4360 /* Check for an unsigned range which has wrapped around the maximum
4361 value thus making n_high < n_low, and normalize it. */
4363 {
4369 /* If the range is of the form +/- [ x+1, x ], we won't
4370 be able to normalize it. But then, it represents the
4371 whole range or the empty set, so make it
4372 +/- [ -, - ]. */
4376 else
4378 }
4379 else
4387 CASE_CONVERT:
4405 /* If we're converting arg0 from an unsigned type, to exp,
4406 a signed type, we will be doing the comparison as unsigned.
4407 The tests above have already verified that LOW and HIGH
4408 are both positive.
4410 So we have to ensure that we will handle large unsigned
4411 values the same way that the current signed bounds treat
4412 negative values. */
4415 {
4416 tree high_positive;
4417 tree equiv_type;
4418 /* For fixed-point modes, we need to pass the saturating flag
4419 as the 2nd parameter. */
4421 equiv_type
4424 else
4425 equiv_type
4428 /* A range without an upper bound is, naturally, unbounded.
4429 Since convert would have cropped a very large value, use
4430 the max value for the destination type. */
4431 high_positive
4438 high_positive),
4441 /* If the low bound is specified, "and" the range with the
4442 range for which the original unsigned value will be
4443 positive. */
4445 {
4448 integer_zero_node),
4449 high_positive))
4453 }
4454 else
4455 {
4456 /* Otherwise, "or" the range with the range of the input
4457 that will be interpreted as negative. */
4460 integer_zero_node),
4461 high_positive))
4465 }
4466 }
4475 }
4476 }
4478 /* Given EXP, a logical expression, set the range it is testing into
4479 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4480 actually being tested. *PLOW and *PHIGH will be made of the same
4481 type as the returned expression. If EXP is not a comparison, we
4482 will most likely not be returning a useful value and range. Set
4483 *STRICT_OVERFLOW_P to true if the return value is only valid
4484 because signed overflow is undefined; otherwise, do not change
4485 *STRICT_OVERFLOW_P. */
4487 tree
4490 {
4498 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4499 and see if we can refine the range. Some of the cases below may not
4500 happen, but it doesn't seem worth worrying about this. We "continue"
4501 the outer loop when we've changed something; otherwise we "break"
4502 the switch, which will "break" the while. */
4508 {
4514 {
4522 }
4531 }
4533 /* If EXP is a constant, we can evaluate whether this is true or false. */
4535 {
4542 }
4546 }
4547 \f
4548 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4549 type, TYPE, return an expression to test if EXP is in (or out of, depending
4550 on IN_P) the range. Return 0 if the test couldn't be created. */
4552 tree
4555 {
4558 /* Disable this optimization for function pointer expressions
4559 on targets that require function pointer canonicalization. */
4566 {
4572 }
4590 {
4592 {
4596 }
4598 }
4600 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4602 {
4606 {
4608 {
4611 etype
4613 else
4616 }
4619 }
4620 }
4622 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4623 This requires wrap-around arithmetics for the type of the expression.
4624 First make sure that arithmetics in this type is valid, then make sure
4625 that it wraps around. */
4631 {
4634 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4635 for the type in question, as we rely on this here. */
4645 else
4647 }
4657 {
4659 {
4664 }
4666 }
4674 }
4675 \f
4676 /* Return the predecessor of VAL in its type, handling the infinite case. */
4678 static tree
4680 {
4686 else
4689 }
4691 /* Return the successor of VAL in its type, handling the infinite case. */
4693 static tree
4695 {
4701 else
4704 }
4706 /* Given two ranges, see if we can merge them into one. Return 1 if we
4707 can, 0 if we can't. Set the output range into the specified parameters. */
4709 bool
4712 {
4716 tree tem;
4726 /* Make range 0 be the range that starts first, or ends last if they
4727 start at the same value. Swap them if it isn't. */
4730 || (lowequal
4733 {
4737 }
4739 /* Now flag two cases, whether the ranges are disjoint or whether the
4740 second range is totally subsumed in the first. Note that the tests
4741 below are simplified by the ones above. */
4747 /* We now have four cases, depending on whether we are including or
4748 excluding the two ranges. */
4750 {
4751 /* If they don't overlap, the result is false. If the second range
4752 is a subset it is the result. Otherwise, the range is from the start
4753 of the second to the end of the first. */
4758 else
4760 }
4763 {
4764 /* If they don't overlap, the result is the first range. If they are
4765 equal, the result is false. If the second range is a subset of the
4766 first, and the ranges begin at the same place, we go from just after
4767 the end of the second range to the end of the first. If the second
4768 range is not a subset of the first, or if it is a subset and both
4769 ranges end at the same place, the range starts at the start of the
4770 first range and ends just before the second range.
4771 Otherwise, we can't describe this as a single range. */
4777 {
4782 {
4783 /* We are in the weird situation where high0 > high1 but
4784 high1 has no successor. Punt. */
4786 }
4787 }
4789 {
4794 {
4795 /* low0 < low1 but low1 has no predecessor. Punt. */
4797 }
4798 }
4799 else
4801 }
4804 {
4805 /* If they don't overlap, the result is the second range. If the second
4806 is a subset of the first, the result is false. Otherwise,
4807 the range starts just after the first range and ends at the
4808 end of the second. */
4813 else
4814 {
4819 {
4820 /* high1 > high0 but high0 has no successor. Punt. */
4822 }
4823 }
4824 }
4826 else
4827 {
4828 /* The case where we are excluding both ranges. Here the complex case
4829 is if they don't overlap. In that case, the only time we have a
4830 range is if they are adjacent. If the second is a subset of the
4831 first, the result is the first. Otherwise, the range to exclude
4832 starts at the beginning of the first range and ends at the end of the
4833 second. */
4835 {
4840 else
4841 {
4842 /* Canonicalize - [min, x] into - [-, x]. */
4845 {
4850 /* FALLTHROUGH */
4863 }
4865 /* Canonicalize - [x, max] into - [x, -]. */
4868 {
4873 /* FALLTHROUGH */
4889 }
4891 /* The ranges might be also adjacent between the maximum and
4892 minimum values of the given type. For
4893 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4894 return + [x + 1, y - 1]. */
4896 {
4903 }
4904 else
4906 }
4907 }
4910 else
4912 }
4916 }
4917 \f
4919 /* Subroutine of fold, looking inside expressions of the form
4920 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4921 of the COND_EXPR. This function is being used also to optimize
4922 A op B ? C : A, by reversing the comparison first.
4924 Return a folded expression whose code is not a COND_EXPR
4925 anymore, or NULL_TREE if no folding opportunity is found. */
4927 static tree
4930 {
4935 tree tem;
4940 /* If we have A op 0 ? A : -A, consider applying the following
4941 transformations:
4943 A == 0? A : -A same as -A
4944 A != 0? A : -A same as A
4945 A >= 0? A : -A same as abs (A)
4946 A > 0? A : -A same as abs (A)
4947 A <= 0? A : -A same as -abs (A)
4948 A < 0? A : -A same as -abs (A)
4950 None of these transformations work for modes with signed
4951 zeros. If A is +/-0, the first two transformations will
4952 change the sign of the result (from +0 to -0, or vice
4953 versa). The last four will fix the sign of the result,
4954 even though the original expressions could be positive or
4955 negative, depending on the sign of A.
4957 Note that all these transformations are correct if A is
4958 NaN, since the two alternatives (A and -A) are also NaNs. */
4965 /* In the case that A is of the form X-Y, '-A' (arg2) may
4966 have already been folded to Y-X, check for that. */
4974 {
4988 /* Fall through. */
5008 }
5010 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5011 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5012 both transformations are correct when A is NaN: A != 0
5013 is then true, and A == 0 is false. */
5017 {
5022 }
5024 /* Try some transformations of A op B ? A : B.
5026 A == B? A : B same as B
5027 A != B? A : B same as A
5028 A >= B? A : B same as max (A, B)
5029 A > B? A : B same as max (B, A)
5030 A <= B? A : B same as min (A, B)
5031 A < B? A : B same as min (B, A)
5033 As above, these transformations don't work in the presence
5034 of signed zeros. For example, if A and B are zeros of
5035 opposite sign, the first two transformations will change
5036 the sign of the result. In the last four, the original
5037 expressions give different results for (A=+0, B=-0) and
5038 (A=-0, B=+0), but the transformed expressions do not.
5040 The first two transformations are correct if either A or B
5041 is a NaN. In the first transformation, the condition will
5042 be false, and B will indeed be chosen. In the case of the
5043 second transformation, the condition A != B will be true,
5044 and A will be chosen.
5046 The conversions to max() and min() are not correct if B is
5047 a number and A is not. The conditions in the original
5048 expressions will be false, so all four give B. The min()
5049 and max() versions would give a NaN instead. */
5052 /* Avoid these transformations if the COND_EXPR may be used
5053 as an lvalue in the C++ front-end. PR c++/19199. */
5054 && (in_gimple_form
5060 {
5065 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
5067 {
5071 }
5074 {
5083 /* In C++ a ?: expression can be an lvalue, so put the
5084 operand which will be used if they are equal first
5085 so that we can convert this back to the
5086 corresponding COND_EXPR. */
5088 {
5097 }
5104 {
5113 }
5128 }
5129 }
5131 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5132 we might still be able to simplify this. For example,
5133 if C1 is one less or one more than C2, this might have started
5134 out as a MIN or MAX and been transformed by this function.
5135 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5141 {
5145 /* We can replace A with C1 in this case. */
5150 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
5151 MIN_EXPR, to preserve the signedness of the comparison. */
5153 OEP_ONLY_CONST)
5157 OEP_ONLY_CONST))
5158 {
5161 arg2));
5164 }
5168 /* If C1 is C2 - 1, this is min(A, C2), with the same care
5169 as above. */
5171 OEP_ONLY_CONST)
5175 OEP_ONLY_CONST))
5176 {
5179 arg2));
5182 }
5186 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
5187 MAX_EXPR, to preserve the signedness of the comparison. */
5189 OEP_ONLY_CONST)
5193 OEP_ONLY_CONST))
5194 {
5197 arg2));
5199 }
5203 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
5205 OEP_ONLY_CONST)
5209 OEP_ONLY_CONST))
5210 {
5213 arg2));
5215 }
5221 }
5224 }
5227 \f
5228 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5229 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5230 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5231 false) >= 2)
5232 #endif
5234 /* EXP is some logical combination of boolean tests. See if we can
5235 merge it into some range test. Return the new tree if so. */
5237 static tree
5240 {
5256 /* If this is an OR operation, invert both sides; we will invert
5257 again at the end. */
5261 /* If both expressions are the same, if we can merge the ranges, and we
5262 can build the range test, return it or it inverted. If one of the
5263 ranges is always true or always false, consider it to be the same
5264 expression as the other. */
5272 {
5276 }
5278 /* On machines where the branch cost is expensive, if this is a
5279 short-circuited branch and the underlying object on both sides
5280 is the same, make a non-short-circuit operation. */
5286 {
5287 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5288 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5289 which cases we can't do this. */
5297 {
5306 {
5309 WARN_STRICT_OVERFLOW_COMPARISON);
5313 }
5314 }
5315 }
5318 }
5319 \f
5320 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5321 bit value. Arrange things so the extra bits will be set to zero if and
5322 only if C is signed-extended to its full width. If MASK is nonzero,
5323 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5325 static tree
5327 {
5330 tree temp;
5335 /* We work by getting just the sign bit into the low-order bit, then
5336 into the high-order bit, then sign-extend. We then XOR that value
5337 with C. */
5340 /* We must use a signed type in order to get an arithmetic right shift.
5341 However, we must also avoid introducing accidental overflows, so that
5342 a subsequent call to integer_zerop will work. Hence we must
5343 do the type conversion here. At this point, the constant is either
5344 zero or one, and the conversion to a signed type can never overflow.
5345 We could get an overflow if this conversion is done anywhere else. */
5354 /* If necessary, convert the type back to match the type of C. */
5359 }
5360 \f
5361 /* For an expression that has the form
5362 (A && B) || ~B
5363 or
5364 (A || B) && ~B,
5365 we can drop one of the inner expressions and simplify to
5366 A || ~B
5367 or
5368 A && ~B
5369 LOC is the location of the resulting expression. OP is the inner
5370 logical operation; the left-hand side in the examples above, while CMPOP
5371 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5372 removing a condition that guards another, as in
5373 (A != NULL && A->...) || A == NULL
5374 which we must not transform. If RHS_ONLY is true, only eliminate the
5375 right-most operand of the inner logical operation. */
5377 static tree
5380 {
5398 {
5401 {
5404 }
5405 }
5407 {
5410 {
5413 }
5414 }
5429 }
5431 /* Find ways of folding logical expressions of LHS and RHS:
5432 Try to merge two comparisons to the same innermost item.
5433 Look for range tests like "ch >= '0' && ch <= '9'".
5434 Look for combinations of simple terms on machines with expensive branches
5435 and evaluate the RHS unconditionally.
5437 For example, if we have p->a == 2 && p->b == 4 and we can make an
5438 object large enough to span both A and B, we can do this with a comparison
5439 against the object ANDed with the a mask.
5441 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5442 operations to do this with one comparison.
5444 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5445 function and the one above.
5447 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5448 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5450 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5451 two operands.
5453 We return the simplified tree or 0 if no optimization is possible. */
5455 static tree
5458 {
5459 /* If this is the "or" of two comparisons, we can do something if
5460 the comparisons are NE_EXPR. If this is the "and", we can do something
5461 if the comparisons are EQ_EXPR. I.e.,
5462 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5464 WANTED_CODE is this operation code. For single bit fields, we can
5465 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5466 comparison for one-bit fields. */
5487 /* Start by getting the comparison codes. Fail if anything is volatile.
5488 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5489 it were surrounded with a NE_EXPR. */
5498 {
5502 }
5505 {
5509 }
5520 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5523 {
5526 {
5531 }
5534 {
5540 }
5541 }
5546 /* If the RHS can be evaluated unconditionally and its operands are
5547 simple, it wins to evaluate the RHS unconditionally on machines
5548 with expensive branches. In this case, this isn't a comparison
5549 that can be merged. */
5556 {
5557 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5568 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5578 }
5580 /* See if the comparisons can be merged. Then get all the parameters for
5581 each side. */
5606 /* It must be true that the inner operation on the lhs of each
5607 comparison must be the same if we are to be able to do anything.
5608 Then see if we have constants. If not, the same must be true for
5609 the rhs's. */
5618 {
5621 }
5626 else
5629 /* If either comparison code is not correct for our logical operation,
5630 fail. However, we can convert a one-bit comparison against zero into
5631 the opposite comparison against that bit being set in the field. */
5635 {
5637 {
5638 /* Make the left operand unsigned, since we are only interested
5639 in the value of one bit. Otherwise we are doing the wrong
5640 thing below. */
5643 }
5644 else
5646 }
5648 /* This is analogous to the code for l_const above. */
5650 {
5652 {
5655 }
5656 else
5658 }
5660 /* See if we can find a mode that contains both fields being compared on
5661 the left. If we can't, fail. Otherwise, update all constants and masks
5662 to be relative to a field of that size. */
5667 volatilep);
5677 {
5680 }
5688 {
5695 {
5699 }
5700 }
5702 {
5709 {
5713 }
5714 }
5716 /* If the right sides are not constant, do the same for it. Also,
5717 disallow this optimization if a size or signedness mismatch occurs
5718 between the left and right sides. */
5720 {
5723 /* Make sure the two fields on the right
5724 correspond to the left without being swapped. */
5732 volatilep);
5742 {
5745 }
5754 /* Make a mask that corresponds to both fields being compared.
5755 Do this for both items being compared. If the operands are the
5756 same size and the bits being compared are in the same position
5757 then we can do this by masking both and comparing the masked
5758 results. */
5762 {
5774 }
5776 /* There is still another way we can do something: If both pairs of
5777 fields being compared are adjacent, we may be able to make a wider
5778 field containing them both.
5780 Note that we still must mask the lhs/rhs expressions. Furthermore,
5781 the mask must be shifted to account for the shift done by
5782 make_bit_field_ref. */
5787 {
5788 tree type;
5804 /* Convert to the smaller type before masking out unwanted bits. */
5807 {
5809 {
5813 }
5815 {
5819 }
5820 }
5829 }
5832 }
5834 /* Handle the case of comparisons with constants. If there is something in
5835 common between the masks, those bits of the constants must be the same.
5836 If not, the condition is always false. Test for this to avoid generating
5837 incorrect code below. */
5842 {
5844 {
5847 }
5848 else
5849 {
5852 }
5853 }
5855 /* Construct the expression we will return. First get the component
5856 reference we will make. Unless the mask is all ones the width of
5857 that field, perform the mask operation. Then compare with the
5858 merged constant. */
5868 }
5869 \f
5870 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5871 constant. */
5873 static tree
5876 {
5879 tree comp_const;
5880 tree minmax_const;
5882 tree inner;
5893 /* If something does not permit us to optimize, return the original tree. */
5901 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5902 and GT_EXPR, doing the rest with recursive calls using logical
5903 simplifications. */
5905 {
5907 {
5908 tree tem
5915 }
5918 return
5920 optimize_minmax_comparison
5922 optimize_minmax_comparison
5927 /* MAX (X, 0) == 0 -> X <= 0 */
5931 /* MAX (X, 0) == 5 -> X == 5 */
5935 /* MAX (X, 0) == -1 -> false */
5939 /* MIN (X, 0) == 0 -> X >= 0 */
5943 /* MIN (X, 0) == 5 -> false */
5946 else
5947 /* MIN (X, 0) == -1 -> X == -1 */
5952 /* MAX (X, 0) > 0 -> X > 0
5953 MAX (X, 0) > 5 -> X > 5 */
5957 /* MAX (X, 0) > -1 -> true */
5961 /* MIN (X, 0) > 0 -> false
5962 MIN (X, 0) > 5 -> false */
5965 else
5966 /* MIN (X, 0) > -1 -> X > -1 */
5971 }
5972 }
5973 \f
5974 /* T is an integer expression that is being multiplied, divided, or taken a
5975 modulus (CODE says which and what kind of divide or modulus) by a
5976 constant C. See if we can eliminate that operation by folding it with
5977 other operations already in T. WIDE_TYPE, if non-null, is a type that
5978 should be used for the computation if wider than our type.
5980 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5981 (X * 2) + (Y * 4). We must, however, be assured that either the original
5982 expression would not overflow or that overflow is undefined for the type
5983 in the language in question.
5985 If we return a non-null expression, it is an equivalent form of the
5986 original computation, but need not be in the original type.
5988 We set *STRICT_OVERFLOW_P to true if the return values depends on
5989 signed overflow being undefined. Otherwise we do not change
5990 *STRICT_OVERFLOW_P. */
5992 static tree
5995 {
5996 /* To avoid exponential search depth, refuse to allow recursion past
5997 three levels. Beyond that (1) it's highly unlikely that we'll find
5998 something interesting and (2) we've probably processed it before
5999 when we built the inner expression. */
6002 tree ret;
6007 depth++;
6009 depth--;
6012 }
6014 static tree
6017 {
6028 /* Don't deal with constants of zero here; they confuse the code below. */
6038 /* Note that we need not handle conditional operations here since fold
6039 already handles those cases. So just do arithmetic here. */
6041 {
6043 /* For a constant, we can always simplify if we are a multiply
6044 or (for divide and modulus) if it is a multiple of our constant. */
6047 {
6050 /* If the multiplication overflowed to INT_MIN then we lost sign
6051 information on it and a subsequent multiplication might
6052 spuriously overflow. See PR68142. */
6057 }
6061 /* If op0 is an expression ... */
6067 /* ... and has wrapping overflow, and its type is smaller
6068 than ctype, then we cannot pass through as widening. */
6073 /* ... or this is a truncation (t is narrower than op0),
6074 then we cannot pass through this narrowing. */
6077 /* ... or signedness changes for division or modulus,
6078 then we cannot pass through this conversion. */
6082 /* ... or has undefined overflow while the converted to
6083 type has not, we cannot do the operation in the inner type
6084 as that would introduce undefined overflow. */
6090 /* Pass the constant down and see if we can make a simplification. If
6091 we can, replace this expression with the inner simplification for
6092 possible later conversion to our or some other type. */
6097 code == MULT_EXPR
6099 strict_overflow_p))))
6104 /* If widening the type changes it from signed to unsigned, then we
6105 must avoid building ABS_EXPR itself as unsigned. */
6107 {
6111 {
6114 }
6116 }
6117 /* If the constant is negative, we cannot simplify this. */
6120 /* FALLTHROUGH */
6122 /* For division and modulus, type can't be unsigned, as e.g.
6123 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6124 For signed types, even with wrapping overflow, this is fine. */
6133 /* If widening the type changes the signedness, then we can't perform
6134 this optimization as that changes the result. */
6138 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6144 {
6151 }
6155 /* If the second operand is constant, this is a multiplication
6156 or floor division, by a power of two, so we can treat it that
6157 way unless the multiplier or divisor overflows. Signed
6158 left-shift overflow is implementation-defined rather than
6159 undefined in C90, so do not convert signed left shift into
6160 multiplication. */
6163 /* const_binop may not detect overflow correctly,
6164 so check for it explicitly here. */
6168 size_one_node,
6169 op1)))
6173 ctype,
6175 t1),
6180 /* See if we can eliminate the operation on both sides. If we can, we
6181 can return a new PLUS or MINUS. If we can't, the only remaining
6182 cases where we can do anything are if the second operand is a
6183 constant. */
6189 /* If not multiplication, we can only do this if both operands
6190 are divisible by c. */
6193 {
6198 }
6200 /* If this was a subtraction, negate OP1 and set it to be an addition.
6201 This simplifies the logic below. */
6203 {
6205 /* If OP1 was not easily negatable, the constant may be OP0. */
6207 {
6210 }
6211 }
6216 /* If either OP1 or C are negative, this optimization is not safe for
6217 some of the division and remainder types while for others we need
6218 to change the code. */
6220 {
6228 }
6230 /* If it's a multiply or a division/modulus operation of a multiple
6231 of our constant, do the operation and verify it doesn't overflow. */
6234 {
6237 /* We allow the constant to overflow with wrapping semantics. */
6241 }
6242 else
6245 /* If we have an unsigned type, we cannot widen the operation since it
6246 will change the result if the original computation overflowed. */
6250 /* If we were able to eliminate our operation from the first side,
6251 apply our operation to the second side and reform the PLUS. */
6255 /* The last case is if we are a multiply. In that case, we can
6256 apply the distributive law to commute the multiply and addition
6257 if the multiplication of the constants doesn't overflow
6258 and overflow is defined. With undefined overflow
6259 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6265 op1);
6270 /* We have a special case here if we are doing something like
6271 (C * 8) % 4 since we know that's zero. */
6274 /* If the multiplication can overflow we cannot optimize this. */
6278 {
6281 }
6283 /* ... fall through ... */
6287 /* If we can extract our operation from the LHS, do so and return a
6288 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6289 do something only if the second operand is a constant. */
6303 /* If these are the same operation types, we can associate them
6304 assuming no overflow. */
6306 {
6316 {
6321 }
6322 }
6324 /* If these operations "cancel" each other, we have the main
6325 optimizations of this pass, which occur when either constant is a
6326 multiple of the other, in which case we replace this with either an
6327 operation or CODE or TCODE.
6329 If we have an unsigned type, we cannot do this since it will change
6330 the result if the original computation overflowed. */
6337 {
6339 {
6346 }
6348 {
6355 }
6356 }
6361 }
6364 }
6365 \f
6366 /* Return a node which has the indicated constant VALUE (either 0 or
6367 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6368 and is of the indicated TYPE. */
6370 tree
6372 {
6381 else
6383 }
6386 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6387 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6388 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6389 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6390 COND is the first argument to CODE; otherwise (as in the example
6391 given here), it is the second argument. TYPE is the type of the
6392 original expression. Return NULL_TREE if no simplification is
6393 possible. */
6395 static tree
6400 {
6410 {
6414 /* If this operand throws an expression, then it does not make
6415 sense to try to perform a logical or arithmetic operation
6416 involving it. */
6421 }
6422 else
6423 {
6428 }
6433 /* This transformation is only worthwhile if we don't have to wrap ARG
6434 in a SAVE_EXPR and the operation can be simplified without recursing
6435 on at least one of the branches once its pushed inside the COND_EXPR. */
6444 {
6448 else
6450 }
6452 {
6456 else
6458 }
6460 /* Check that we have simplified at least one of the branches. */
6465 }
6467 \f
6468 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6470 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6471 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6472 ADDEND is the same as X.
6474 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6475 and finite. The problematic cases are when X is zero, and its mode
6476 has signed zeros. In the case of rounding towards -infinity,
6477 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6478 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6480 bool
6482 {
6486 /* Don't allow the fold with -fsignaling-nans. */
6490 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6494 /* In a vector or complex, we would need to check the sign of all zeros. */
6498 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6502 /* The mode has signed zeros, and we have to honor their sign.
6503 In this situation, there is only one case we can return true for.
6504 X - 0 is the same as X unless rounding towards -infinity is
6505 supported. */
6507 }
6509 /* Subroutine of fold() that optimizes comparisons of a division by
6510 a nonzero integer constant against an integer constant, i.e.
6511 X/C1 op C2.
6513 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6514 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6515 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6517 The function returns the constant folded tree if a simplification
6518 can be made, and NULL_TREE otherwise. */
6520 static tree
6523 {
6531 /* We have to do this the hard way to detect unsigned overflow.
6532 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6538 {
6543 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6547 }
6549 {
6553 {
6572 }
6573 }
6574 else
6575 {
6576 /* A negative divisor reverses the relational operators. */
6582 {
6601 }
6602 }
6605 {
6626 {
6629 }
6634 {
6637 }
6642 {
6645 }
6650 {
6653 }
6658 }
6661 }
6664 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6665 equality/inequality test, then return a simplified form of the test
6666 using a sign testing. Otherwise return NULL. TYPE is the desired
6667 result type. */
6669 static tree
6672 tree result_type)
6673 {
6674 /* If this is testing a single bit, we can optimize the test. */
6678 {
6679 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6680 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6684 /* This is only a win if casting to a signed type is cheap,
6685 i.e. when arg00's type is not a partial mode. */
6688 {
6691 result_type,
6694 }
6695 }
6698 }
6700 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6701 equality/inequality test, then return a simplified form of
6702 the test using shifts and logical operations. Otherwise return
6703 NULL. TYPE is the desired result type. */
6705 tree
6708 {
6709 /* If this is testing a single bit, we can optimize the test. */
6713 {
6722 /* First, see if we can fold the single bit test into a sign-bit
6723 test. */
6725 result_type);
6729 /* Otherwise we have (A & C) != 0 where C is a single bit,
6730 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6731 Similarly for (A & C) == 0. */
6733 /* If INNER is a right shift of a constant and it plus BITNUM does
6734 not overflow, adjust BITNUM and INNER. */
6740 {
6743 }
6745 /* If we are going to be able to omit the AND below, we must do our
6746 operations as unsigned. If we must use the AND, we have a choice.
6747 Normally unsigned is faster, but for some machines signed is. */
6765 /* Put the AND last so it can combine with more things. */
6768 /* Make sure to return the proper type. */
6772 }
6774 }
6776 /* Check whether we are allowed to reorder operands arg0 and arg1,
6777 such that the evaluation of arg1 occurs before arg0. */
6779 static bool
6781 {
6788 }
6790 /* Test whether it is preferable two swap two operands, ARG0 and
6791 ARG1, for example because ARG0 is an integer constant and ARG1
6792 isn't. If REORDER is true, only recommend swapping if we can
6793 evaluate the operands in reverse order. */
6795 bool
6797 {
6815 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6816 for commutative and comparison operators. Ensuring a canonical
6817 form allows the optimizers to find additional redundancies without
6818 having to explicitly check for both orderings. */
6824 /* Put SSA_NAMEs last. */
6830 /* Put variables last. */
6837 }
6840 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6841 means A >= Y && A != MAX, but in this case we know that
6842 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6844 static tree
6846 {
6853 else
6862 {
6865 }
6867 {
6870 }
6871 else
6878 {
6879 /* Convert the pointer types into integer before taking the difference. */
6883 }
6884 else
6891 }
6893 /* Fold a sum or difference of at least one multiplication.
6894 Returns the folded tree or NULL if no simplification could be made. */
6896 static tree
6899 {
6903 /* (A * C) +- (B * C) -> (A+-B) * C.
6904 (A * C) +- A -> A * (C+-1).
6905 We are most concerned about the case where C is a constant,
6906 but other combinations show up during loop reduction. Since
6907 it is not difficult, try all four possibilities. */
6910 {
6913 }
6915 {
6918 }
6919 else
6920 {
6921 /* We cannot generate constant 1 for fract. */
6926 }
6928 {
6931 }
6933 {
6935 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6936 the purpose of this canonicalization. */
6940 {
6943 }
6944 else
6946 }
6947 else
6948 {
6949 /* We cannot generate constant 1 for fract. */
6954 }
6966 /* No identical multiplicands; see if we can find a common
6967 power-of-two factor in non-power-of-two multiplies. This
6968 can help in multi-dimensional array access. */
6971 {
6974 tree maybe_same;
6978 /* Move min of absolute values to int11. */
6980 {
6985 }
6986 else
6990 /* The remainder should not be a constant, otherwise we
6991 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6992 increased the number of multiplications necessary. */
6994 {
7002 }
7003 }
7013 }
7015 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7016 specified by EXPR into the buffer PTR of length LEN bytes.
7017 Return the number of bytes placed in the buffer, or zero
7018 upon failure. */
7020 static int
7022 {
7036 {
7038 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7039 number of bytes. */
7043 {
7050 else
7052 }
7053 else
7058 }
7060 }
7063 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7064 specified by EXPR into the buffer PTR of length LEN bytes.
7065 Return the number of bytes placed in the buffer, or zero
7066 upon failure. */
7068 static int
7070 {
7074 FIXED_VALUE_TYPE value;
7090 }
7093 /* Subroutine of native_encode_expr. Encode the REAL_CST
7094 specified by EXPR into the buffer PTR of length LEN bytes.
7095 Return the number of bytes placed in the buffer, or zero
7096 upon failure. */
7098 static int
7100 {
7106 /* There are always 32 bits in each long, no matter the size of
7107 the hosts long. We handle floating point representations with
7108 up to 192 bits. */
7122 {
7127 {
7134 else
7136 }
7137 else
7143 }
7145 }
7147 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7148 specified by EXPR into the buffer PTR of length LEN bytes.
7149 Return the number of bytes placed in the buffer, or zero
7150 upon failure. */
7152 static int
7154 {
7156 tree part;
7171 }
7174 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7175 specified by EXPR into the buffer PTR of length LEN bytes.
7176 Return the number of bytes placed in the buffer, or zero
7177 upon failure. */
7179 static int
7181 {
7191 {
7193 {
7196 }
7207 }
7209 }
7212 /* Subroutine of native_encode_expr. Encode the STRING_CST
7213 specified by EXPR into the buffer PTR of length LEN bytes.
7214 Return the number of bytes placed in the buffer, or zero
7215 upon failure. */
7217 static int
7219 {
7221 HOST_WIDE_INT total_bytes;
7235 {
7238 {
7241 }
7244 }
7245 else
7248 }
7251 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7252 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7253 buffer PTR of length LEN bytes. If OFF is not -1 then start
7254 the encoding at byte offset OFF and encode at most LEN bytes.
7255 Return the number of bytes placed in the buffer, or zero upon failure. */
7257 int
7259 {
7260 /* We don't support starting at negative offset and -1 is special. */
7265 {
7286 }
7287 }
7290 /* Subroutine of native_interpret_expr. Interpret the contents of
7291 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7292 If the buffer cannot be interpreted, return NULL_TREE. */
7294 static tree
7296 {
7306 }
7309 /* Subroutine of native_interpret_expr. Interpret the contents of
7310 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7311 If the buffer cannot be interpreted, return NULL_TREE. */
7313 static tree
7315 {
7317 double_int result;
7318 FIXED_VALUE_TYPE fixed_value;
7328 }
7331 /* Subroutine of native_interpret_expr. Interpret the contents of
7332 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7333 If the buffer cannot be interpreted, return NULL_TREE. */
7335 static tree
7337 {
7341 /* There are always 32 bits in each long, no matter the size of
7342 the hosts long. We handle floating point representations with
7343 up to 192 bits. */
7344 REAL_VALUE_TYPE r;
7355 {
7356 /* Both OFFSET and BYTE index within a long;
7357 bitpos indexes the whole float. */
7360 {
7367 else
7369 }
7370 else
7371 {
7374 {
7375 /* Reverse bytes within each long, or within the entire float
7376 if it's smaller than a long (for HFmode). */
7379 }
7380 }
7384 }
7388 }
7391 /* Subroutine of native_interpret_expr. Interpret the contents of
7392 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7393 If the buffer cannot be interpreted, return NULL_TREE. */
7395 static tree
7397 {
7412 }
7415 /* Subroutine of native_interpret_expr. Interpret the contents of
7416 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7417 If the buffer cannot be interpreted, return NULL_TREE. */
7419 static tree
7421 {
7434 {
7439 }
7441 }
7444 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7445 the buffer PTR of length LEN as a constant of type TYPE. For
7446 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7447 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7448 return NULL_TREE. */
7450 tree
7452 {
7454 {
7476 }
7477 }
7479 /* Returns true if we can interpret the contents of a native encoding
7480 as TYPE. */
7482 static bool
7484 {
7486 {
7499 }
7500 }
7502 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7503 TYPE at compile-time. If we're unable to perform the conversion
7504 return NULL_TREE. */
7506 static tree
7508 {
7509 /* We support up to 512-bit values (for V8DFmode). */
7513 /* Check that the host and target are sane. */
7522 }
7524 /* Build an expression for the address of T. Folds away INDIRECT_REF
7525 to avoid confusing the gimplify process. */
7527 tree
7529 {
7530 /* The size of the object is not relevant when talking about its address. */
7535 {
7540 }
7550 {
7555 }
7556 else
7560 }
7562 /* Build an expression for the address of T. */
7564 tree
7566 {
7570 }
7572 /* Fold a unary expression of code CODE and type TYPE with operand
7573 OP0. Return the folded expression if folding is successful.
7574 Otherwise, return NULL_TREE. */
7576 tree
7578 {
7579 tree tem;
7580 tree arg0;
7588 {
7591 {
7592 /* Don't use STRIP_NOPS, because signedness of argument type
7593 matters. */
7595 }
7596 else
7597 {
7598 /* Strip any conversions that don't change the mode. This
7599 is safe for every expression, except for a comparison
7600 expression because its signedness is derived from its
7601 operands.
7603 Note that this is done as an internal manipulation within
7604 the constant folder, in order to find the simplest
7605 representation of the arguments so that their form can be
7606 studied. In any cases, the appropriate type conversions
7607 should be put back in the tree that will get out of the
7608 constant folder. */
7610 }
7613 {
7616 {
7620 }
7621 }
7622 }
7629 {
7636 {
7650 /* If this was a conversion, and all we did was to move into
7651 inside the COND_EXPR, bring it back out. But leave it if
7652 it is a conversion from integer to integer and the
7653 result precision is no wider than a word since such a
7654 conversion is cheap and may be optimized away by combine,
7655 while it couldn't if it were outside the COND_EXPR. Then return
7656 so we don't get into an infinite recursion loop taking the
7657 conversion out and then back in. */
7669 && (INTEGRAL_TYPE_P
7682 }
7683 }
7686 {
7692 CASE_CONVERT:
7696 {
7697 /* If we have (type) (a CMP b) and type is an integral type, return
7698 new expression involving the new type. Canonicalize
7699 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7700 non-integral type.
7701 Do not fold the result as that would not simplify further, also
7702 folding again results in recursions. */
7712 }
7714 /* Handle (T *)&A.B.C for A being of type T and B and C
7715 living at offset zero. This occurs frequently in
7716 C++ upcasting and then accessing the base. */
7720 {
7722 tree offset;
7723 machine_mode mode;
7725 tree base
7729 /* If the reference was to a (constant) zero offset, we can use
7730 the address of the base if it has the same base type
7731 as the result type and the pointer type is unqualified. */
7738 }
7742 /* Detect assigning a bitfield. */
7744 && DECL_BIT_FIELD
7746 {
7747 /* Don't leave an assignment inside a conversion
7748 unless assigning a bitfield. */
7750 /* First do the assignment, then return converted constant. */
7755 }
7757 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7758 constants (if x has signed type, the sign bit cannot be set
7759 in c). This folds extension into the BIT_AND_EXPR.
7760 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7761 very likely don't have maximal range for their precision and this
7762 transformation effectively doesn't preserve non-maximal ranges. */
7766 {
7777 <= HOST_BITS_PER_WIDE_INT
7779 {
7783 cst &= HOST_WIDE_INT_M1U
7787 && !flag_syntax_only
7790 {
7794 }
7795 }
7797 {
7802 }
7803 }
7805 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7806 cast (T1)X will fold away. We assume that this happens when X itself
7807 is a cast. */
7811 {
7815 return fold_build_pointer_plus_loc
7817 }
7819 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7820 of the same precision, and X is an integer type not narrower than
7821 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7827 {
7833 }
7835 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7836 type of X and Y (integer types only). */
7841 {
7842 /* Be careful not to introduce new overflows. */
7843 tree mult_type;
7846 else
7850 {
7857 }
7858 }
7864 {
7869 }
7880 /* Convert fabs((double)float) into (double)fabsf(float). */
7883 {
7889 targ0));
7890 }
7894 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7913 /* Note that the operand of this must be an int
7914 and its values must be 0 or 1.
7915 ("true" is a fixed value perhaps depending on the language,
7916 but we don't handle values other than 1 correctly yet.) */
7923 /* Fold *&X to X if X is an lvalue. */
7925 {
7932 }
7938 }
7941 /* If the operation was a conversion do _not_ mark a resulting constant
7942 with TREE_OVERFLOW if the original constant was not. These conversions
7943 have implementation defined behavior and retaining the TREE_OVERFLOW
7944 flag here would confuse later passes such as VRP. */
7945 tree
7948 {
7957 }
7959 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7960 operands OP0 and OP1. LOC is the location of the resulting expression.
7961 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7962 Return the folded expression if folding is successful. Otherwise,
7963 return NULL_TREE. */
7964 static tree
7967 {
7968 tree tem;
7970 /* We only do these simplifications if we are optimizing. */
7974 /* Check for things like (A || B) && (A || C). We can convert this
7975 to A || (B && C). Note that either operator can be any of the four
7976 truth and/or operations and the transformation will still be
7977 valid. Also note that we only care about order for the
7978 ANDIF and ORIF operators. If B contains side effects, this
7979 might change the truth-value of A. */
7986 {
8006 /* This case if tricky because we must either have commutative
8007 operators or else A10 must not have side-effects. */
8013 a01);
8014 }
8016 /* See if we can build a range comparison. */
8022 {
8026 }
8030 {
8034 }
8036 /* Check for the possibility of merging component references. If our
8037 lhs is another similar operation, try to merge its rhs with our
8038 rhs. Then try to merge our lhs and rhs. */
8052 {
8059 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8060 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8061 We don't want to pack more than two leafs to a non-IF AND/OR
8062 expression.
8063 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8064 equal to IF-CODE, then we don't want to add right-hand operand.
8065 If the inner right-hand side of left-hand operand has
8066 side-effects, or isn't simple, then we can't add to it,
8067 as otherwise we might destroy if-sequence. */
8070 /* Needed for sequence points to handle trappings, and
8071 side-effects. */
8073 {
8075 arg1);
8077 tem);
8078 }
8079 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8080 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8083 /* Needed for sequence points to handle trappings, and
8084 side-effects. */
8086 {
8091 }
8092 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8093 into (A OR B).
8094 For sequence point consistancy, we need to check for trapping,
8095 and side-effects. */
8099 }
8102 }
8104 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8105 by changing CODE to reduce the magnitude of constants involved in
8106 ARG0 of the comparison.
8107 Returns a canonicalized comparison tree if a simplification was
8108 possible, otherwise returns NULL_TREE.
8109 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8110 valid if signed overflow is undefined. */
8112 static tree
8116 {
8121 /* Match A +- CST code arg1. We can change this only if overflow
8122 is undefined. */
8125 /* In principle pointers also have undefined overflow behavior,
8126 but that causes problems elsewhere. */
8133 /* Identify the constant in arg0 and its sign. */
8137 /* Overflowed constants and zero will cause problems. */
8142 /* See if we can reduce the magnitude of the constant in
8143 arg0 by changing the comparison code. */
8144 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8148 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8152 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8156 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8160 else
8164 /* Now build the constant reduced in magnitude. But not if that
8165 would produce one outside of its types range. */
8181 }
8183 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8184 overflow further. Try to decrease the magnitude of constants involved
8185 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8186 and put sole constants at the second argument position.
8187 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8189 static tree
8192 {
8193 tree t;
8198 /* Try canonicalization by simplifying arg0. */
8203 {
8207 }
8209 /* Try canonicalization by simplifying arg1 using the swapped
8210 comparison. */
8218 }
8220 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8221 space. This is used to avoid issuing overflow warnings for
8222 expressions like &p->x which can not wrap. */
8224 static bool
8226 {
8233 wide_int wi_offset;
8239 else
8255 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8256 array. */
8258 {
8259 HOST_WIDE_INT base_size;
8264 }
8267 }
8269 /* Return the HOST_WIDE_INT least significant bits of T, a sizetype
8270 kind INTEGER_CST. This makes sure to properly sign-extend the
8271 constant. */
8273 static HOST_WIDE_INT
8275 {
8281 }
8283 /* Subroutine of fold_binary. This routine performs all of the
8284 transformations that are common to the equality/inequality
8285 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8286 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8287 fold_binary should call fold_binary. Fold a comparison with
8288 tree code CODE and type TYPE with operands OP0 and OP1. Return
8289 the folded comparison or NULL_TREE. */
8291 static tree
8294 {
8304 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1. */
8306 && (equality_code
8313 {
8314 const enum tree_code
8321 /* If the constant operation overflowed this can be
8322 simplified as a comparison against INT_MAX/INT_MIN. */
8325 {
8329 /* Get the sign of the constant on the lhs if the
8330 operation were VARIABLE + CONST1. */
8334 /* The sign of the constant determines if we overflowed
8335 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8336 Canonicalize to the INT_MIN overflow by swapping the comparison
8337 if necessary. */
8341 /* We now can look at the canonicalized case
8342 VARIABLE + 1 CODE2 INT_MIN
8343 and decide on the result. */
8345 {
8349 return
8355 return
8360 }
8361 }
8362 else
8363 {
8366 "when changing X +- C1 cmp C2 to "
8368 WARN_STRICT_OVERFLOW_COMPARISON);
8370 }
8371 }
8373 /* For comparisons of pointers we can decompose it to a compile time
8374 comparison of the base objects and the offsets into the object.
8375 This requires at least one operand being an ADDR_EXPR or a
8376 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8382 {
8385 machine_mode mode;
8389 /* Get base and offset for the access. Strip ADDR_EXPR for
8390 get_inner_reference, but put it back by stripping INDIRECT_REF
8391 off the base object if possible. indirect_baseN will be true
8392 if baseN is not an address but refers to the object itself. */
8395 {
8396 base0
8402 else
8404 }
8406 {
8410 {
8413 }
8416 {
8421 {
8424 }
8425 }
8426 }
8430 {
8431 base1
8437 else
8439 }
8441 {
8445 {
8448 }
8451 {
8456 {
8459 }
8460 }
8461 }
8463 /* If we have equivalent bases we might be able to simplify. */
8467 {
8468 /* We can fold this expression to a constant if the non-constant
8469 offset parts are equal. */
8478 {
8484 "occur when comparing P +- C1 with "
8486 WARN_STRICT_OVERFLOW_CONDITIONAL);
8489 {
8503 }
8504 }
8505 /* We can simplify the comparison to a comparison of the variable
8506 offset parts if the constant offset parts are equal.
8507 Be careful to use signed sizetype here because otherwise we
8508 mess with array offsets in the wrong way. This is possible
8509 because pointer arithmetic is restricted to retain within an
8510 object and overflow on pointer differences is undefined as of
8511 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8513 && (equality_code
8516 {
8517 /* By converting to signed sizetype we cover middle-end pointer
8518 arithmetic which operates on unsigned pointer types of size
8519 type size and ARRAY_REF offsets which are properly sign or
8520 zero extended from their type in case it is narrower than
8521 sizetype. */
8524 else
8528 else
8535 "occur when comparing P +- C1 with "
8537 WARN_STRICT_OVERFLOW_COMPARISON);
8540 }
8541 }
8542 /* For equal offsets we can simplify to a comparison of the
8543 base addresses. */
8545 && (indirect_base0
8547 && (indirect_base1
8552 {
8558 }
8559 }
8561 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8562 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8563 the resulting offset is smaller in absolute value than the
8564 original one and has the same sign. */
8573 {
8578 tree cst;
8580 "occur when combining constants around "
8583 /* Put the constant on the side where it doesn't overflow and is
8584 of lower absolute value and of same sign than before. */
8591 {
8594 variable1,
8598 }
8606 {
8612 variable2);
8613 }
8614 }
8620 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8621 constant, we can simplify it. */
8626 {
8630 }
8632 /* If we are comparing an expression that just has comparisons
8633 of two integer values, arithmetic expressions of those comparisons,
8634 and constants, we can simplify it. There are only three cases
8635 to check: the two values can either be equal, the first can be
8636 greater, or the second can be greater. Fold the expression for
8637 those three values. Since each value must be 0 or 1, we have
8638 eight possibilities, each of which corresponds to the constant 0
8639 or 1 or one of the six possible comparisons.
8641 This handles common cases like (a > b) == 0 but also handles
8642 expressions like ((x > y) - (y > x)) > 0, which supposedly
8643 occur in macroized code. */
8646 {
8651 /* Don't handle degenerate cases here; they should already
8652 have been handled anyway. */
8661 {
8665 /* We can't just pass T to eval_subst in case cval1 or cval2
8666 was the same as ARG1. */
8668 tree high_result
8672 arg1);
8673 tree equal_result
8677 arg1);
8678 tree low_result
8682 arg1);
8684 /* All three of these results should be 0 or 1. Confirm they are.
8685 Then use those values to select the proper code to use. */
8690 {
8691 /* Make a 3-bit mask with the high-order bit being the
8692 value for `>', the next for '=', and the low for '<'. */
8696 {
8698 /* Always false. */
8719 /* Always true. */
8721 }
8724 {
8728 }
8730 }
8731 }
8732 }
8734 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8735 into a single range test. */
8743 {
8747 }
8750 }
8753 /* Subroutine of fold_binary. Optimize complex multiplications of the
8754 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8755 argument EXPR represents the expression "z" of type TYPE. */
8757 static tree
8759 {
8764 {
8767 }
8769 {
8772 }
8773 else
8774 {
8778 }
8787 }
8790 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8791 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8793 static bool
8795 {
8799 {
8802 }
8804 {
8810 else
8812 }
8813 else
8819 }
8821 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8822 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8823 NULL_TREE otherwise. */
8825 static tree
8827 {
8844 {
8848 }
8851 {
8857 }
8858 else
8860 }
8862 /* Try to fold a pointer difference of type TYPE two address expressions of
8863 array references AREF0 and AREF1 using location LOC. Return a
8864 simplified expression for the difference or NULL_TREE. */
8866 static tree
8869 {
8874 /* If the bases are array references as well, recurse. If the bases
8875 are pointer indirections compute the difference of the pointers.
8876 If the bases are equal, we are set. */
8879 && (base_offset
8883 && (base_offset
8889 {
8895 base_offset,
8898 }
8900 }
8902 /* If the real or vector real constant CST of type TYPE has an exact
8903 inverse, return it, else return NULL. */
8905 tree
8907 {
8908 REAL_VALUE_TYPE r;
8910 machine_mode mode;
8914 {
8930 {
8935 }
8941 }
8942 }
8944 /* Mask out the tz least significant bits of X of type TYPE where
8945 tz is the number of trailing zeroes in Y. */
8946 static wide_int
8948 {
8953 }
8955 /* Return true when T is an address and is known to be nonzero.
8956 For floating point we further ensure that T is not denormal.
8957 Similar logic is present in nonzero_address in rtlanal.h.
8959 If the return value is based on the assumption that signed overflow
8960 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8961 change *STRICT_OVERFLOW_P. */
8963 static bool
8965 {
8969 /* Doing something useful for floating point would need more work. */
8975 {
8978 strict_overflow_p);
8984 strict_overflow_p);
8992 }
8995 {
8998 strict_overflow_p);
9006 strict_overflow_p);
9021 strict_overflow_p);
9025 strict_overflow_p);
9028 {
9040 }
9044 }
9046 }
9048 /* Return true when T is an address and is known to be nonzero.
9049 Handle warnings about undefined signed overflow. */
9051 static bool
9053 {
9060 "determining that expression is always "
9062 WARN_STRICT_OVERFLOW_MISC);
9064 }
9066 /* Fold a binary expression of code CODE and type TYPE with operands
9067 OP0 and OP1. LOC is the location of the resulting expression.
9068 Return the folded expression if folding is successful. Otherwise,
9069 return NULL_TREE. */
9071 tree
9074 {
9089 /* Strip any conversions that don't change the mode. This is
9090 safe for every expression, except for a comparison expression
9091 because its signedness is derived from its operands. So, in
9092 the latter case, only strip conversions that don't change the
9093 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9094 preserved.
9096 Note that this is done as an internal manipulation within the
9097 constant folder, in order to find the simplest representation
9098 of the arguments so that their form can be studied. In any
9099 cases, the appropriate type conversions should be put back in
9100 the tree that will get out of the constant folder. */
9103 {
9106 }
9107 else
9108 {
9111 }
9113 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9114 constant but we can't do arithmetic on them. */
9116 {
9119 {
9123 }
9124 }
9126 /* If this is a commutative operation, and ARG0 is a constant, move it
9127 to ARG1 to reduce the number of tests below. */
9132 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9133 to ARG1 to reduce the number of tests below. */
9142 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9144 First check for cases where an arithmetic operation is applied to a
9145 compound, conditional, or comparison operation. Push the arithmetic
9146 operation inside the compound or conditional to see if any folding
9147 can then be done. Convert comparison to conditional for this purpose.
9148 The also optimizes non-constant cases that used to be done in
9149 expand_expr.
9151 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9152 one of the operands is a comparison and the other is a comparison, a
9153 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9154 code below would make the expression more complex. Change it to a
9155 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9156 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9169 {
9173 boolean_type_node,
9181 }
9185 {
9187 {
9192 tem);
9193 }
9196 {
9201 tem);
9202 }
9207 {
9213 }
9218 {
9224 }
9225 }
9228 {
9230 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9233 {
9239 }
9241 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9244 {
9245 tree base;
9246 HOST_WIDE_INT coffset;
9255 }
9260 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9266 arg1),
9268 arg0)));
9274 {
9275 /* X + (X / CST) * -CST is X % CST. */
9280 {
9289 cst0));
9290 }
9291 }
9293 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9294 one. Make sure the type is not saturating and has the signedness of
9295 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9296 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9303 {
9307 }
9310 {
9311 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9312 (plus (plus (mult) (mult)) (foo)) so that we can
9313 take advantage of the factoring cases below. */
9322 {
9328 else
9341 parg0),
9343 marg)),
9347 return
9353 parg1)));
9354 }
9355 }
9356 else
9357 {
9358 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9359 to __complex__ ( x, y ). This is not the same for SNaNs or
9360 if signed zeros are involved. */
9364 {
9371 {
9375 {
9381 }
9383 {
9389 }
9390 }
9391 }
9399 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9400 We associate floats only if the user has specified
9401 -fassociative-math. */
9405 {
9410 {
9411 tree tree0;
9414 }
9415 }
9416 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9417 We associate floats only if the user has specified
9418 -fassociative-math. */
9422 {
9427 {
9428 tree tree0;
9431 }
9432 }
9433 }
9435 bit_rotate:
9436 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9437 is a rotate of A by C1 bits. */
9438 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9439 is a rotate of A by B bits. */
9440 {
9442 tree rtype;
9451 /* Only create rotates in complete modes. Other cases are not
9452 expanded properly. */
9455 {
9469 {
9473 code0 == LSHIFT_EXPR
9477 }
9479 {
9487 element_precision
9491 return
9494 ? LROTATE_EXPR
9499 }
9501 {
9509 element_precision
9513 return fold_convert_loc
9516 ? LROTATE_EXPR
9520 }
9521 }
9522 }
9524 associate:
9525 /* In most languages, can't associate operations on floats through
9526 parentheses. Rather than remember where the parentheses were, we
9527 don't associate floats at all, unless the user has specified
9528 -fassociative-math.
9529 And, we need to make sure type is not saturating. */
9533 {
9539 /* Split both trees into variables, constants, and literals. Then
9540 associate each group together, the constants with literals,
9541 then the result with variables. This increases the chances of
9542 literals being recombined later and of generating relocatable
9543 expressions for the sum of a constant and literal. */
9548 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9552 /* With undefined overflow prefer doing association in a type
9553 which wraps on overflow, if that is one of the operand types. */
9556 {
9564 }
9566 /* With undefined overflow we can only associate constants with one
9567 variable, and constants whose association doesn't overflow. */
9570 {
9572 {
9578 {
9581 }
9588 {
9591 }
9597 /* The only case we can still associate with two variables
9598 is if they cancel out. */
9602 }
9603 }
9605 /* Only do something if we found more than two objects. Otherwise,
9606 nothing has changed and we risk infinite recursion. */
9612 {
9624 /* Preserve the MINUS_EXPR if the negative part of the literal is
9625 greater than the positive part. Otherwise, the multiplicative
9626 folding code (i.e extract_muldiv) may be fooled in case
9627 unsigned constants are subtracted, like in the following
9628 example: ((X*2 + 4) - 8U)/2. */
9630 {
9634 {
9638 }
9639 else
9640 {
9644 }
9645 }
9647 /* Don't introduce overflows through reassociation. */
9654 {
9656 return
9660 else
9661 {
9664 return
9668 }
9669 }
9672 return
9675 }
9676 }
9681 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9690 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9691 __complex__ ( x, -y ). This is not the same for SNaNs or if
9692 signed zeros are involved. */
9696 {
9703 {
9707 {
9709 arg1r ? arg1r
9714 }
9716 {
9720 arg1i ? arg1i
9723 }
9724 }
9725 }
9727 /* A - B -> A + (-B) if B is easily negatable. */
9731 /* Avoid this transformation if B is a positive REAL_CST. */
9739 /* Fold &a[i] - &a[j] to i-j. */
9744 {
9750 }
9753 && flag_unsafe_math_optimizations
9759 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9760 one. Make sure the type is not saturating and has the signedness of
9761 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9762 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9769 {
9773 }
9779 {
9780 /* Transform x * -C into -x * C if x is easily negatable. */
9790 /* (A + A) * C -> A * 2 * C */
9802 /* ((T) (X /[ex] C)) * C cancels out if the conversion is
9803 sign-changing only. */
9813 {
9816 "occur when simplifying "
9818 WARN_STRICT_OVERFLOW_MISC);
9820 }
9822 /* Optimize z * conj(z) for integer complex numbers. */
9829 }
9830 else
9831 {
9832 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9833 This is not the same for NaNs or if signed zeros are
9834 involved. */
9840 {
9843 return
9849 return
9854 }
9856 /* Optimize z * conj(z) for floating point complex numbers.
9857 Guarded by flag_unsafe_math_optimizations as non-finite
9858 imaginary components don't produce scalar results. */
9869 {
9871 /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x. */
9873 && optimize
9875 {
9879 {
9882 }
9883 }
9884 }
9885 }
9889 /* Canonicalize (X & C1) | C2. */
9893 {
9898 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9906 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9911 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9912 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9913 mode which allows further optimizations. */
9918 {
9922 {
9925 }
9926 }
9933 c3)),
9934 arg1);
9935 }
9937 /* See if this can be simplified into a rotate first. If that
9938 is unsuccessful continue in the association code. */
9942 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9950 /* See if this can be simplified into a rotate first. If that
9951 is unsuccessful continue in the association code. */
9955 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9960 {
9961 tree tem2;
9968 }
9969 /* Fold ~X & 1 as (X & 1) == 0. */
9973 {
9974 tree tem2;
9981 }
9982 /* Fold !X & 1 as X == 0. */
9985 {
9989 }
9991 /* Fold (X ^ Y) & Y as ~X & Y. */
9994 {
9999 }
10000 /* Fold (X ^ Y) & X as ~Y & X. */
10004 {
10009 }
10010 /* Fold X & (X ^ Y) as X & ~Y. */
10013 {
10018 }
10019 /* Fold X & (Y ^ X) as ~Y & X. */
10023 {
10028 }
10030 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10031 multiple of 1 << CST. */
10033 {
10040 }
10042 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10043 bits from CST2. */
10047 {
10055 {
10056 /* Avoid the transform if arg1 is a mask of some
10057 mode which allows further optimizations. */
10064 }
10065 }
10067 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10068 ((A & N) + B) & M -> (A + B) & M
10069 Similarly if (N & M) == 0,
10070 ((A | N) + B) & M -> (A + B) & M
10071 and for - instead of + (or unary - instead of +)
10072 and/or ^ instead of |.
10073 If B is constant and (B & M) == 0, fold into A & M. */
10075 {
10084 {
10087 wide_int cst0;
10089 /* Now we know that arg0 is (C + D) or (C - D) or
10090 -C and arg1 (M) is == (1LL << cst) - 1.
10091 Store C into PMOP[0] and D into PMOP[1]. */
10095 {
10098 }
10105 {
10115 {
10118 }
10121 /* If C or D is of the form (A & N) where
10122 (N & M) == M, or of the form (A | N) or
10123 (A ^ N) where (N & M) == 0, replace it with A. */
10127 /* If C or D is a N where (N & M) == 0, it can be
10128 omitted (assumed 0). */
10136 }
10138 /* Only build anything new if we optimized one or both arguments
10139 above. */
10143 {
10146 {
10147 /* Perform the operations in a type that has defined
10148 overflow behavior. */
10154 }
10159 {
10167 else
10169 }
10172 else
10175 /* TEM is now the new binary +, - or unary - replacement. */
10179 }
10180 }
10181 }
10183 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10186 {
10191 return
10193 }
10198 /* Don't touch a floating-point divide by zero unless the mode
10199 of the constant can represent infinity. */
10205 /* (-A) / (-B) -> A / B */
10217 /* Fall through */
10220 /* Simplify A / (B << N) where A and B are positive and B is
10221 a power of 2, to A >> (N + log2(B)). */
10226 {
10229 {
10237 WARN_STRICT_OVERFLOW_MISC);
10243 }
10244 }
10246 /* Fall through */
10254 /* Convert -A / -B to A / B when the type is signed and overflow is
10255 undefined. */
10259 {
10262 "when distributing negation across "
10264 WARN_STRICT_OVERFLOW_MISC);
10269 }
10273 {
10276 "when distributing negation across "
10278 WARN_STRICT_OVERFLOW_MISC);
10283 }
10285 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10286 operation, EXACT_DIV_EXPR.
10288 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10289 At one time others generated faster code, it's not clear if they do
10290 after the last round to changes to the DIV code in expmed.c. */
10301 {
10305 WARN_STRICT_OVERFLOW_MISC);
10307 }
10319 {
10323 WARN_STRICT_OVERFLOW_MISC);
10325 }
10333 /* Since negative shift count is not well-defined,
10334 don't try to compute it in the compiler. */
10340 /* If we have a rotate of a bit operation with the rotate count and
10341 the second operand of the bit operation both constant,
10342 permute the two operations. */
10354 /* Two consecutive rotates adding up to the some integer
10355 multiple of the precision of the type can be ignored. */
10370 /* Note that the operands of this must be ints
10371 and their values must be 0 or 1.
10372 ("true" is a fixed value perhaps depending on the language.) */
10373 /* If first arg is constant zero, return it. */
10377 /* If either arg is constant true, drop it. */
10381 /* Preserve sequence points. */
10384 /* If second arg is constant zero, result is zero, but first arg
10385 must be evaluated. */
10388 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10389 case will be handled here. */
10393 /* !X && X is always false. */
10397 /* X && !X is always false. */
10402 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10403 means A >= Y && A != MAX, but in this case we know that
10404 A < X <= MAX. */
10408 {
10416 }
10425 /* Note that the operands of this must be ints
10426 and their values must be 0 or true.
10427 ("true" is a fixed value perhaps depending on the language.) */
10428 /* If first arg is constant true, return it. */
10432 /* If either arg is constant zero, drop it. */
10436 /* Preserve sequence points. */
10439 /* If second arg is constant true, result is true, but we must
10440 evaluate first arg. */
10443 /* Likewise for first arg, but note this only occurs here for
10444 TRUTH_OR_EXPR. */
10448 /* !X || X is always true. */
10452 /* X || !X is always true. */
10457 /* (X && !Y) || (!X && Y) is X ^ Y */
10460 {
10477 }
10486 /* If the second arg is constant zero, drop it. */
10489 /* If the second arg is constant true, this is a logical inversion. */
10491 {
10494 }
10495 /* Identical arguments cancel to zero. */
10499 /* !X ^ X is always true. */
10504 /* X ^ !X is always true. */
10520 /* bool_var != 1 becomes !bool_var. */
10527 /* bool_var == 0 becomes !bool_var. */
10534 /* !exp != 0 becomes !exp */
10539 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10548 {
10552 val,
10556 }
10558 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
10565 {
10567 code == NE_EXPR
10570 }
10572 /* If this is an EQ or NE comparison with zero and ARG0 is
10573 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10574 two operations, but the latter can be done in one less insn
10575 on machines that have only two-operand insns or on which a
10576 constant cannot be the first operand. */
10579 {
10584 {
10591 arg1);
10592 }
10595 {
10602 arg1);
10603 }
10604 }
10606 /* If this is an NE or EQ comparison of zero against the result of a
10607 signed MOD operation whose second operand is a power of 2, make
10608 the MOD operation unsigned since it is simpler and equivalent. */
10616 {
10626 }
10628 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10629 C1 is a valid shift constant, and C2 is a power of two, i.e.
10630 a single bit. */
10634 == INTEGER_CST
10637 {
10642 /* Check for a valid shift count. */
10644 {
10648 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10649 can be rewritten as (X & (C2 << C1)) != 0. */
10651 {
10656 }
10657 /* Otherwise, for signed (arithmetic) shifts,
10658 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10659 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10663 /* Otherwise, of unsigned (logical) shifts,
10664 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10665 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10666 else
10670 arg000);
10671 }
10672 }
10674 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
10675 Similarly for NE_EXPR. */
10679 {
10683 tree dandnotc
10686 notc);
10690 }
10692 /* If this is a comparison of a field, we may be able to simplify it. */
10695 /* Handle the constant case even without -O
10696 to make sure the warnings are given. */
10698 {
10702 }
10704 /* Optimize comparisons of strlen vs zero to a compare of the
10705 first character of the string vs zero. To wit,
10706 strlen(ptr) == 0 => *ptr == 0
10707 strlen(ptr) != 0 => *ptr != 0
10708 Other cases should reduce to one of these two (or a constant)
10709 due to the return value of strlen being unsigned. */
10712 {
10720 {
10725 }
10726 }
10728 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10729 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10733 {
10738 {
10740 {
10743 }
10746 }
10747 }
10749 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10750 (X & C) == 0 when C is a single bit. */
10755 {
10762 arg1));
10763 }
10765 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10766 constant C is a power of two, i.e. a single bit. */
10773 {
10777 }
10779 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10780 when is C is a power of two, i.e. a single bit. */
10787 {
10793 }
10797 {
10800 }
10802 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10805 {
10818 arg01),
10827 arg01),
10836 arg00),
10845 arg00),
10847 }
10851 {
10858 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10859 operand_equal_p guarantees no side-effects so we don't need
10860 to use omit_one_operand on Z. */
10864 arg10));
10868 arg11));
10872 arg10));
10876 arg11));
10878 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10881 {
10887 }
10888 }
10890 /* Attempt to simplify equality/inequality comparisons of complex
10891 values. Only lower the comparison if the result is known or
10892 can be simplified to a single scalar comparison. */
10897 {
10902 {
10905 }
10906 else
10907 {
10910 }
10913 {
10916 }
10917 else
10918 {
10921 }
10925 {
10927 {
10932 }
10933 else
10934 {
10939 }
10940 }
10944 {
10946 {
10951 }
10952 else
10953 {
10958 }
10959 }
10960 }
10972 /* Transform comparisons of the form X +- C CMP X. */
10979 {
10986 else
10989 /* (X - c) > X becomes false. */
10993 {
10997 "occur when assuming that (X - c) > X "
10999 WARN_STRICT_OVERFLOW_ALL);
11001 }
11003 /* Likewise (X + c) < X becomes false. */
11007 {
11011 "occur when assuming that "
11013 WARN_STRICT_OVERFLOW_ALL);
11015 }
11017 /* Convert (X - c) <= X to true. */
11022 {
11026 "occur when assuming that "
11028 WARN_STRICT_OVERFLOW_ALL);
11030 }
11032 /* Convert (X + c) >= X to true. */
11037 {
11041 "occur when assuming that "
11043 WARN_STRICT_OVERFLOW_ALL);
11045 }
11048 {
11049 /* Convert X + c > X and X - c < X to true for integers. */
11053 {
11056 "not occur when assuming that "
11058 WARN_STRICT_OVERFLOW_ALL);
11060 }
11065 {
11068 "not occur when assuming that "
11070 WARN_STRICT_OVERFLOW_ALL);
11072 }
11074 /* Convert X + c <= X and X - c >= X to false for integers. */
11078 {
11081 "not occur when assuming that "
11083 WARN_STRICT_OVERFLOW_ALL);
11085 }
11090 {
11093 "not occur when assuming that "
11095 WARN_STRICT_OVERFLOW_ALL);
11097 }
11098 }
11099 }
11101 /* If we are comparing an ABS_EXPR with a constant, we can
11102 convert all the cases into explicit comparisons, but they may
11103 well not be faster than doing the ABS and one comparison.
11104 But ABS (X) <= C is a range comparison, which becomes a subtraction
11105 and a comparison, and is probably faster. */
11119 /* Convert ABS_EXPR<x> >= 0 to true. */
11126 {
11129 "when simplifying comparison of "
11131 WARN_STRICT_OVERFLOW_CONDITIONAL);
11134 arg0);
11135 }
11137 /* Convert ABS_EXPR<x> < 0 to false. */
11142 {
11145 "when simplifying comparison of "
11147 WARN_STRICT_OVERFLOW_CONDITIONAL);
11150 arg0);
11151 }
11153 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11154 and similarly for >= into !=. */
11164 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11165 otherwise Y might be >= # of bits in X's type and thus e.g.
11166 (unsigned char) (1 << Y) for Y 15 might be 0.
11167 If the cast is widening, then 1 << Y should have unsigned type,
11168 otherwise if Y is number of bits in the signed shift type minus 1,
11169 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11170 31 might be 0xffffffff80000000. */
11181 {
11187 }
11199 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11200 {
11212 }
11217 /* When pedantic, a compound expression can be neither an lvalue
11218 nor an integer constant expression. */
11221 /* Don't let (0, 0) be null pointer constant. */
11227 /* An ASSERT_EXPR should never be passed to fold_binary. */
11233 }
11235 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11236 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11237 of GOTO_EXPR. */
11239 static tree
11241 {
11243 {
11250 /* ... fall through ... */
11254 }
11255 }
11257 /* Return whether the sub-tree ST contains a label which is accessible from
11258 outside the sub-tree. */
11260 static bool
11262 {
11263 return
11265 }
11267 /* Fold a ternary expression of code CODE and type TYPE with operands
11268 OP0, OP1, and OP2. Return the folded expression if folding is
11269 successful. Otherwise, return NULL_TREE. */
11271 tree
11274 {
11275 tree tem;
11282 /* If this is a commutative operation, and OP0 is a constant, move it
11283 to OP1 to reduce the number of tests below. */
11292 /* Strip any conversions that don't change the mode. This is safe
11293 for every expression, except for a comparison expression because
11294 its signedness is derived from its operands. So, in the latter
11295 case, only strip conversions that don't change the signedness.
11297 Note that this is done as an internal manipulation within the
11298 constant folder, in order to find the simplest representation of
11299 the arguments so that their form can be studied. In any cases,
11300 the appropriate type conversions should be put back in the tree
11301 that will get out of the constant folder. */
11303 {
11306 }
11309 {
11312 }
11315 {
11318 }
11321 {
11325 {
11331 }
11336 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11337 so all simple results must be passed through pedantic_non_lvalue. */
11339 {
11342 /* Only optimize constant conditions when the selected branch
11343 has the same type as the COND_EXPR. This avoids optimizing
11344 away "c ? x : throw", where the throw has a void type.
11345 Avoid throwing away that operand which contains label. */
11352 }
11354 {
11359 {
11364 {
11372 }
11376 }
11377 }
11379 /* If we have A op B ? A : C, we may be able to convert this to a
11380 simpler expression, depending on the operation and the values
11381 of B and C. Signed zeros prevent all of these transformations,
11382 for reasons given above each one.
11384 Also try swapping the arguments and inverting the conditional. */
11389 {
11393 }
11397 op2,
11400 {
11404 {
11408 }
11409 }
11411 /* If the second operand is simpler than the third, swap them
11412 since that produces better jump optimization results. */
11415 {
11417 /* See if this can be inverted. If it can't, possibly because
11418 it was a floating-point inequality comparison, don't do
11419 anything. */
11423 }
11425 /* Convert A ? 1 : 0 to simply A. */
11430 /* If we try to convert OP0 to our type, the
11431 call to fold will try to move the conversion inside
11432 a COND, which will recurse. In that case, the COND_EXPR
11433 is probably the best choice, so leave it alone. */
11437 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11438 over COND_EXPR in cases such as floating point comparisons. */
11447 arg0)));
11449 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11454 {
11455 /* sign_bit_p looks through both zero and sign extensions,
11456 but for this optimization only sign extensions are
11457 usable. */
11460 {
11463 {
11466 }
11468 }
11469 /* sign_bit_p only checks ARG1 bits within A's precision.
11470 If <sign bit of A> has wider type than A, bits outside
11471 of A's precision in <sign bit of A> need to be checked.
11472 If they are all 0, this optimization needs to be done
11473 in unsigned A's type, if they are all 1 in signed A's type,
11474 otherwise this can't be done. */
11480 {
11482 tree tem_type;
11495 {
11498 }
11500 {
11503 }
11504 else
11506 }
11509 return
11515 arg1)));
11516 }
11518 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11519 already handled above. */
11524 {
11533 }
11535 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11536 is probably obsolete because the first operand should be a
11537 truth value (that's why we have the two cases above), but let's
11538 leave it in until we can confirm this for all front-ends. */
11550 /* Disable the transformations below for vectors, since
11551 fold_binary_op_with_conditional_arg may undo them immediately,
11552 yielding an infinite loop. */
11556 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11565 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11570 {
11572 /* Only perform transformation if ARG0 is easily inverted. */
11576 ? BIT_IOR_EXPR
11579 arg1);
11580 }
11582 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11587 {
11589 /* Only perform transformation if ARG0 is easily inverted. */
11595 op2);
11596 }
11598 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11610 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11611 of fold_ternary on them. */
11621 {
11631 {
11636 {
11644 }
11646 /* Constructor elements can be subvectors. */
11649 {
11653 }
11655 /* We keep an exact subset of the constructor elements. */
11657 {
11663 {
11667 }
11675 CONSTRUCTOR_ELT
11678 }
11679 /* The bitfield references a single constructor element. */
11681 {
11686 else
11690 }
11691 }
11692 }
11694 /* A bit-field-ref that referenced the full argument can be stripped. */
11700 /* On constants we can use native encode/interpret to constant
11701 fold (nearly) all BIT_FIELD_REFs. */
11705 /* This limitation should not be necessary, we just need to
11706 round this up to mode size. */
11708 /* Need bit-shifting of the buffer to relax the following. */
11710 {
11715 /* ??? We cannot tell native_encode_expr to start at
11716 some random byte only. So limit us to a reasonable amount
11717 of work. */
11719 {
11724 {
11730 }
11731 }
11732 }
11737 /* For integers we can decompose the FMA if possible. */
11749 {
11765 {
11770 /* Make sure that the perm value is in an acceptable
11771 range. */
11780 else
11785 }
11788 {
11793 }
11798 {
11803 }
11809 {
11813 }
11818 /* Some targets are deficient and fail to expand a single
11819 argument permutation while still allowing an equivalent
11820 2-argument version. */
11824 {
11827 }
11830 {
11837 }
11841 }
11847 }
11849 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11850 of an array (or vector). */
11852 tree
11854 {
11859 {
11862 {
11863 /* Static constructors for variably sized objects makes no sense. */
11867 }
11868 }
11879 offset_int max_index;
11884 {
11885 /* Array constructor might explicitly set index, or specify a range,
11886 or leave index NULL meaning that it is next index after previous
11887 one. */
11889 {
11892 else
11893 {
11897 }
11898 }
11899 else
11900 {
11906 }
11908 /* Do we have match? */
11912 }
11914 }
11916 /* Perform constant folding and related simplification of EXPR.
11917 The related simplifications include x*1 => x, x*0 => 0, etc.,
11918 and application of the associative law.
11919 NOP_EXPR conversions may be removed freely (as long as we
11920 are careful not to change the type of the overall expression).
11921 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11922 but we can constant-fold them if they have constant operands. */
11924 #ifdef ENABLE_FOLD_CHECKING
11925 # define fold(x) fold_1 (x)
11927 static
11928 #endif
11929 tree
11931 {
11935 tree tem;
11938 /* Return right away if a constant. */
11942 /* CALL_EXPR-like objects with variable numbers of operands are
11943 treated specially. */
11945 {
11947 {
11950 }
11952 }
11955 {
11960 {
11978 }
11979 }
11982 {
11984 {
11991 {
11996 }
11999 }
12001 /* Return a VECTOR_CST if possible. */
12003 {
12009 tree val;
12015 }
12023 }
12025 #ifdef ENABLE_FOLD_CHECKING
12026 #undef fold
12033 /* When --enable-checking=fold, compute a digest of expr before
12034 and after actual fold call to see if fold did not accidentally
12035 change original expr. */
12037 tree
12039 {
12040 tree ret;
12060 }
12062 void
12064 {
12075 }
12077 static void
12079 {
12081 }
12083 static void
12086 {
12092 recursive_label:
12102 {
12103 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12108 }
12115 {
12116 /* Allow these fields to be modified. */
12117 tree tmp;
12125 {
12128 }
12129 }
12140 {
12143 {
12158 }
12162 {
12175 }
12192 {
12198 }
12201 {
12203 {
12206 }
12208 }
12219 {
12222 }
12232 }
12233 }
12235 /* Helper function for outputting the checksum of a tree T. When
12236 debugging with gdb, you can "define mynext" to be "next" followed
12237 by "call debug_fold_checksum (op0)", then just trace down till the
12238 outputs differ. */
12240 DEBUG_FUNCTION void
12242 {
12257 }
12259 #endif
12261 /* Fold a unary tree expression with code CODE of type TYPE with an
12262 operand OP0. LOC is the location of the resulting expression.
12263 Return a folded expression if successful. Otherwise, return a tree
12264 expression with code CODE of type TYPE with an operand OP0. */
12266 tree
12269 {
12270 tree tem;
12271 #ifdef ENABLE_FOLD_CHECKING
12280 #endif
12286 #ifdef ENABLE_FOLD_CHECKING
12293 #endif
12295 }
12297 /* Fold a binary tree expression with code CODE of type TYPE with
12298 operands OP0 and OP1. LOC is the location of the resulting
12299 expression. Return a folded expression if successful. Otherwise,
12300 return a tree expression with code CODE of type TYPE with operands
12301 OP0 and OP1. */
12303 tree
12306 MEM_STAT_DECL)
12307 {
12308 tree tem;
12309 #ifdef ENABLE_FOLD_CHECKING
12326 #endif
12332 #ifdef ENABLE_FOLD_CHECKING
12347 #endif
12349 }
12351 /* Fold a ternary tree expression with code CODE of type TYPE with
12352 operands OP0, OP1, and OP2. Return a folded expression if
12353 successful. Otherwise, return a tree expression with code CODE of
12354 type TYPE with operands OP0, OP1, and OP2. */
12356 tree
12359 {
12360 tree tem;
12361 #ifdef ENABLE_FOLD_CHECKING
12385 #endif
12392 #ifdef ENABLE_FOLD_CHECKING
12415 #endif
12417 }
12419 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12420 arguments in ARGARRAY, and a null static chain.
12421 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12422 of type TYPE from the given operands as constructed by build_call_array. */
12424 tree
12427 {
12428 tree tem;
12429 #ifdef ENABLE_FOLD_CHECKING
12448 #endif
12454 #ifdef ENABLE_FOLD_CHECKING
12470 #endif
12472 }
12474 /* Perform constant folding and related simplification of initializer
12475 expression EXPR. These behave identically to "fold_buildN" but ignore
12476 potential run-time traps and exceptions that fold must preserve. */
12478 #define START_FOLD_INIT \
12479 int saved_signaling_nans = flag_signaling_nans;\
12480 int saved_trapping_math = flag_trapping_math;\
12481 int saved_rounding_math = flag_rounding_math;\
12482 int saved_trapv = flag_trapv;\
12483 int saved_folding_initializer = folding_initializer;\
12484 flag_signaling_nans = 0;\
12485 flag_trapping_math = 0;\
12486 flag_rounding_math = 0;\
12487 flag_trapv = 0;\
12488 folding_initializer = 1;
12490 #define END_FOLD_INIT \
12491 flag_signaling_nans = saved_signaling_nans;\
12492 flag_trapping_math = saved_trapping_math;\
12493 flag_rounding_math = saved_rounding_math;\
12494 flag_trapv = saved_trapv;\
12495 folding_initializer = saved_folding_initializer;
12497 tree
12500 {
12501 tree result;
12502 START_FOLD_INIT;
12506 END_FOLD_INIT;
12508 }
12510 tree
12513 {
12514 tree result;
12515 START_FOLD_INIT;
12519 END_FOLD_INIT;
12521 }
12523 tree
12526 {
12527 tree result;
12528 START_FOLD_INIT;
12532 END_FOLD_INIT;
12534 }
12536 #undef START_FOLD_INIT
12537 #undef END_FOLD_INIT
12539 /* Determine if first argument is a multiple of second argument. Return 0 if
12540 it is not, or we cannot easily determined it to be.
12542 An example of the sort of thing we care about (at this point; this routine
12543 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12544 fold cases do now) is discovering that
12546 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12548 is a multiple of
12550 SAVE_EXPR (J * 8)
12552 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12554 This code also handles discovering that
12556 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12558 is a multiple of 8 so we don't have to worry about dealing with a
12559 possible remainder.
12561 Note that we *look* inside a SAVE_EXPR only to determine how it was
12562 calculated; it is not safe for fold to do much of anything else with the
12563 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12564 at run time. For example, the latter example above *cannot* be implemented
12565 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12566 evaluation time of the original SAVE_EXPR is not necessarily the same at
12567 the time the new expression is evaluated. The only optimization of this
12568 sort that would be valid is changing
12570 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12572 divided by 8 to
12574 SAVE_EXPR (I) * SAVE_EXPR (J)
12576 (where the same SAVE_EXPR (J) is used in the original and the
12577 transformed version). */
12579 int
12581 {
12589 {
12591 /* Bitwise and provides a power of two multiple. If the mask is
12592 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12595 /* FALLTHRU */
12608 {
12612 /* const_binop may not detect overflow correctly,
12613 so check for it explicitly here. */
12617 size_one_node,
12618 op1)))
12621 }
12625 /* Can't handle conversions from non-integral or wider integral type. */
12631 /* .. fall through ... */
12648 SIGNED);
12652 }
12653 }
12655 #define tree_expr_nonnegative_warnv_p(X, Y) \
12658 #define RECURSE(X) \
12659 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12661 /* Return true if CODE or TYPE is known to be non-negative. */
12663 static bool
12665 {
12668 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12669 have a signed:1 type (where the value is -1 and 0). */
12672 }
12674 /* Return true if (CODE OP0) is known to be non-negative. If the return
12675 value is based on the assumption that signed overflow is undefined,
12676 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12677 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12679 bool
12682 {
12687 {
12689 /* We can't return 1 if flag_wrapv is set because
12690 ABS_EXPR<INT_MIN> = INT_MIN. */
12694 {
12697 }
12705 CASE_CONVERT:
12706 {
12711 {
12715 {
12719 }
12720 }
12722 {
12728 }
12729 }
12734 }
12736 /* We don't know sign of `t', so be conservative and return false. */
12738 }
12740 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12741 value is based on the assumption that signed overflow is undefined,
12742 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12743 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12745 bool
12749 {
12754 {
12760 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12761 both unsigned and at least 2 bits shorter than the result. */
12765 {
12770 {
12774 }
12775 }
12780 {
12781 /* x * x is always non-negative for floating point x
12782 or without overflow. */
12785 {
12790 }
12791 }
12793 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12794 both unsigned and their total bits is shorter than the result. */
12798 {
12817 {
12827 }
12828 }
12855 }
12857 /* We don't know sign of `t', so be conservative and return false. */
12859 }
12861 /* Return true if T is known to be non-negative. If the return
12862 value is based on the assumption that signed overflow is undefined,
12863 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12864 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12866 bool
12868 {
12873 {
12887 /* Limit the depth of recursion to avoid quadratic behavior.
12888 This is expected to catch almost all occurrences in practice.
12889 If this code misses important cases that unbounded recursion
12890 would not, passes that need this information could be revised
12891 to provide it through dataflow propagation. */
12899 }
12900 }
12902 /* Return true if T is known to be non-negative. If the return
12903 value is based on the assumption that signed overflow is undefined,
12904 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12905 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12907 bool
12910 {
12912 {
12913 CASE_CFN_ACOS:
12914 CASE_CFN_ACOSH:
12915 CASE_CFN_CABS:
12916 CASE_CFN_COSH:
12917 CASE_CFN_ERFC:
12918 CASE_CFN_EXP:
12919 CASE_CFN_EXP10:
12920 CASE_CFN_EXP2:
12921 CASE_CFN_FABS:
12922 CASE_CFN_FDIM:
12923 CASE_CFN_HYPOT:
12924 CASE_CFN_POW10:
12925 CASE_CFN_FFS:
12926 CASE_CFN_PARITY:
12927 CASE_CFN_POPCOUNT:
12928 CASE_CFN_CLZ:
12929 CASE_CFN_CLRSB:
12932 /* Always true. */
12935 CASE_CFN_SQRT:
12936 /* sqrt(-0.0) is -0.0. */
12941 CASE_CFN_ASINH:
12942 CASE_CFN_ATAN:
12943 CASE_CFN_ATANH:
12944 CASE_CFN_CBRT:
12945 CASE_CFN_CEIL:
12946 CASE_CFN_ERF:
12947 CASE_CFN_EXPM1:
12948 CASE_CFN_FLOOR:
12949 CASE_CFN_FMOD:
12950 CASE_CFN_FREXP:
12951 CASE_CFN_ICEIL:
12952 CASE_CFN_IFLOOR:
12953 CASE_CFN_IRINT:
12954 CASE_CFN_IROUND:
12955 CASE_CFN_LCEIL:
12956 CASE_CFN_LDEXP:
12957 CASE_CFN_LFLOOR:
12958 CASE_CFN_LLCEIL:
12959 CASE_CFN_LLFLOOR:
12960 CASE_CFN_LLRINT:
12961 CASE_CFN_LLROUND:
12962 CASE_CFN_LRINT:
12963 CASE_CFN_LROUND:
12964 CASE_CFN_MODF:
12965 CASE_CFN_NEARBYINT:
12966 CASE_CFN_RINT:
12967 CASE_CFN_ROUND:
12968 CASE_CFN_SCALB:
12969 CASE_CFN_SCALBLN:
12970 CASE_CFN_SCALBN:
12971 CASE_CFN_SIGNBIT:
12972 CASE_CFN_SIGNIFICAND:
12973 CASE_CFN_SINH:
12974 CASE_CFN_TANH:
12975 CASE_CFN_TRUNC:
12976 /* True if the 1st argument is nonnegative. */
12979 CASE_CFN_FMAX:
12980 /* True if the 1st OR 2nd arguments are nonnegative. */
12983 CASE_CFN_FMIN:
12984 /* True if the 1st AND 2nd arguments are nonnegative. */
12987 CASE_CFN_COPYSIGN:
12988 /* True if the 2nd argument is nonnegative. */
12991 CASE_CFN_POWI:
12992 /* True if the 1st argument is nonnegative or the second
12993 argument is an even integer. */
12999 CASE_CFN_POW:
13000 /* True if the 1st argument is nonnegative or the second
13001 argument is an even integer valued real. */
13003 {
13004 REAL_VALUE_TYPE c;
13005 HOST_WIDE_INT n;
13010 {
13011 REAL_VALUE_TYPE cint;
13015 }
13016 }
13021 }
13023 }
13025 /* Return true if T is known to be non-negative. If the return
13026 value is based on the assumption that signed overflow is undefined,
13027 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13028 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13030 static bool
13032 {
13038 {
13040 {
13044 /* If the initializer is non-void, then it's a normal expression
13045 that will be assigned to the slot. */
13049 /* Otherwise, the initializer sets the slot in some way. One common
13050 way is an assignment statement at the end of the initializer. */
13052 {
13060 else
13062 }
13068 }
13071 {
13077 arg0,
13078 arg1,
13080 }
13093 }
13094 }
13096 #undef RECURSE
13097 #undef tree_expr_nonnegative_warnv_p
13099 /* Return true if T is known to be non-negative. If the return
13100 value is based on the assumption that signed overflow is undefined,
13101 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13102 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13104 bool
13106 {
13113 {
13135 }
13138 {
13164 }
13165 }
13167 /* Return true if `t' is known to be non-negative. Handle warnings
13168 about undefined signed overflow. */
13170 bool
13172 {
13179 "determining that expression is always "
13181 WARN_STRICT_OVERFLOW_MISC);
13183 }
13186 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13187 For floating point we further ensure that T is not denormal.
13188 Similar logic is present in nonzero_address in rtlanal.h.
13190 If the return value is based on the assumption that signed overflow
13191 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13192 change *STRICT_OVERFLOW_P. */
13194 bool
13197 {
13199 {
13202 strict_overflow_p);
13205 {
13211 strict_overflow_p));
13212 }
13217 strict_overflow_p);
13221 }
13224 }
13226 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13227 For floating point we further ensure that T is not denormal.
13228 Similar logic is present in nonzero_address in rtlanal.h.
13230 If the return value is based on the assumption that signed overflow
13231 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13232 change *STRICT_OVERFLOW_P. */
13234 bool
13236 tree type,
13237 tree op0,
13239 {
13242 {
13246 {
13247 /* With the presence of negative values it is hard
13248 to say something. */
13255 /* One of operands must be positive and the other non-negative. */
13256 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13257 overflows, on a twos-complement machine the sum of two
13258 nonnegative numbers can never be zero. */
13260 strict_overflow_p)
13262 strict_overflow_p));
13263 }
13268 {
13270 strict_overflow_p)
13272 strict_overflow_p))
13273 {
13276 }
13277 }
13286 {
13289 }
13296 {
13300 /* When both operands are nonzero, then MAX must be too. */
13302 strict_overflow_p))
13305 /* MAX where operand 0 is positive is positive. */
13307 strict_overflow_p);
13308 }
13309 /* MAX where operand 1 is positive is positive. */
13314 {
13318 }
13323 strict_overflow_p)
13325 strict_overflow_p));
13329 }
13332 }
13334 /* Return true when T is an address and is known to be nonzero.
13335 For floating point we further ensure that T is not denormal.
13336 Similar logic is present in nonzero_address in rtlanal.h.
13338 If the return value is based on the assumption that signed overflow
13339 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13340 change *STRICT_OVERFLOW_P. */
13342 bool
13344 {
13347 {
13352 {
13361 /* For objects in symbol table check if we know they are non-zero.
13362 Don't do anything for variables and functions before symtab is built;
13363 it is quite possible that they will be declared weak later. */
13365 {
13371 else
13373 }
13375 /* Function local objects are never NULL. */
13382 /* Constants are never weak. */
13387 }
13395 {
13399 }
13404 }
13406 }
13408 #define integer_valued_real_p(X) \
13411 #define RECURSE(X) \
13412 ((integer_valued_real_p) (X, depth + 1))
13414 /* Return true if the floating point result of (CODE OP0) has an
13415 integer value. We also allow +Inf, -Inf and NaN to be considered
13416 integer values.
13418 DEPTH is the current nesting depth of the query. */
13420 bool
13422 {
13424 {
13431 CASE_CONVERT:
13432 {
13439 }
13443 }
13445 }
13447 /* Return true if the floating point result of (CODE OP0 OP1) has an
13448 integer value. We also allow +Inf, -Inf and NaN to be considered
13449 integer values.
13451 DEPTH is the current nesting depth of the query. */
13453 bool
13455 {
13457 {
13467 }
13469 }
13471 /* Return true if the floating point result of calling FNDECL with arguments
13472 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13473 considered integer values. If FNDECL takes fewer than 2 arguments,
13474 the remaining ARGn are null.
13476 DEPTH is the current nesting depth of the query. */
13478 bool
13480 {
13482 {
13483 CASE_CFN_CEIL:
13484 CASE_CFN_FLOOR:
13485 CASE_CFN_NEARBYINT:
13486 CASE_CFN_RINT:
13487 CASE_CFN_ROUND:
13488 CASE_CFN_TRUNC:
13491 CASE_CFN_FMIN:
13492 CASE_CFN_FMAX:
13497 }
13499 }
13501 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13502 has an integer value. We also allow +Inf, -Inf and NaN to be
13503 considered integer values.
13505 DEPTH is the current nesting depth of the query. */
13507 bool
13509 {
13511 {
13519 /* Limit the depth of recursion to avoid quadratic behavior.
13520 This is expected to catch almost all occurrences in practice.
13521 If this code misses important cases that unbounded recursion
13522 would not, passes that need this information could be revised
13523 to provide it through dataflow propagation. */
13527 depth));
13531 }
13533 }
13535 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13536 has an integer value. We also allow +Inf, -Inf and NaN to be
13537 considered integer values.
13539 DEPTH is the current nesting depth of the query. */
13541 static bool
13543 {
13545 {
13556 }
13558 }
13560 #undef RECURSE
13561 #undef integer_valued_real_p
13563 /* Return true if the floating point expression T has an integer value.
13564 We also allow +Inf, -Inf and NaN to be considered integer values.
13566 DEPTH is the current nesting depth of the query. */
13568 bool
13570 {
13576 {
13592 }
13595 {
13601 {
13610 }
13614 }
13615 }
13617 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13618 attempt to fold the expression to a constant without modifying TYPE,
13619 OP0 or OP1.
13621 If the expression could be simplified to a constant, then return
13622 the constant. If the expression would not be simplified to a
13623 constant, then return NULL_TREE. */
13625 tree
13627 {
13630 }
13632 /* Given the components of a unary expression CODE, TYPE and OP0,
13633 attempt to fold the expression to a constant without modifying
13634 TYPE or OP0.
13636 If the expression could be simplified to a constant, then return
13637 the constant. If the expression would not be simplified to a
13638 constant, then return NULL_TREE. */
13640 tree
13642 {
13645 }
13647 /* If EXP represents referencing an element in a constant string
13648 (either via pointer arithmetic or array indexing), return the
13649 tree representing the value accessed, otherwise return NULL. */
13651 tree
13653 {
13657 {
13659 tree index;
13660 tree string;
13665 else
13666 {
13670 /* Optimize the special-case of a zero lower bound.
13672 We convert the low_bound to sizetype to avoid some problems
13673 with constant folding. (E.g. suppose the lower bound is 1,
13674 and its mode is QI. Without the conversion,l (ARRAY
13675 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13676 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13682 }
13695 }
13697 }
13699 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13700 an integer constant, real, or fixed-point constant.
13702 TYPE is the type of the result. */
13704 static tree
13706 {
13710 {
13712 {
13719 }
13726 {
13727 FIXED_VALUE_TYPE f;
13732 /* Propagate overflow flags. */
13736 }
13740 }
13743 }
13745 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13746 an integer constant or real constant.
13748 TYPE is the type of the result. */
13750 tree
13752 {
13756 {
13758 {
13759 /* If the value is unsigned or non-negative, then the absolute value
13760 is the same as the ordinary value. */
13764 /* If the value is negative, then the absolute value is
13765 its negation. */
13766 else
13767 {
13772 }
13773 }
13779 else
13785 }
13788 }
13790 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13791 constant. TYPE is the type of the result. */
13793 static tree
13795 {
13799 }
13801 /* Given CODE, a relational operator, the target type, TYPE and two
13802 constant operands OP0 and OP1, return the result of the
13803 relational operation. If the result is not a compile time
13804 constant, then return NULL_TREE. */
13806 static tree
13808 {
13811 /* From here on, the only cases we handle are when the result is
13812 known to be a constant. */
13815 {
13819 /* Handle the cases where either operand is a NaN. */
13821 {
13823 {
13851 }
13854 }
13857 }
13860 {
13864 }
13866 /* Handle equality/inequality of complex constants. */
13868 {
13879 else
13881 }
13884 {
13891 {
13903 }
13906 }
13908 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13910 To compute GT, swap the arguments and do LT.
13911 To compute GE, do LT and invert the result.
13912 To compute LE, swap the arguments, do LT and invert the result.
13913 To compute NE, do EQ and invert the result.
13915 Therefore, the code below must handle only EQ and LT. */
13918 {
13921 }
13923 /* Note that it is safe to invert for real values here because we
13924 have already handled the one case that it matters. */
13928 {
13931 }
13933 /* Compute a result for LT or EQ if args permit;
13934 Otherwise return T. */
13936 {
13939 else
13941 }
13942 else
13948 }
13950 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13951 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13952 itself. */
13954 tree
13956 {
13957 /* If the expression does not have side effects then we don't have to wrap
13958 it with a cleanup point expression. */
13962 /* If the expression is a return, check to see if the expression inside the
13963 return has no side effects or the right hand side of the modify expression
13964 inside the return. If either don't have side effects set we don't need to
13965 wrap the expression in a cleanup point expression. Note we don't check the
13966 left hand side of the modify because it should always be a return decl. */
13968 {
13975 }
13978 }
13980 /* Given a pointer value OP0 and a type TYPE, return a simplified version
13981 of an indirection through OP0, or NULL_TREE if no simplification is
13982 possible. */
13984 tree
13986 {
13988 tree subtype;
13996 {
13999 /* *&CONST_DECL -> to the value of the const decl. */
14002 /* *&p => p; make sure to handle *&"str"[cst] here. */
14004 {
14008 else
14010 }
14011 /* *(foo *)&fooarray => fooarray[0] */
14014 && (!in_gimple_form
14016 {
14026 }
14027 /* *(foo *)&complexfoo => __real__ complexfoo */
14031 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14034 {
14038 }
14039 }
14043 {
14049 {
14050 tree op00type;
14054 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14057 {
14069 }
14070 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14073 {
14077 }
14078 /* ((foo *)&fooarray)[1] => fooarray[1] */
14081 {
14091 }
14092 }
14093 }
14095 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14098 && (!in_gimple_form
14100 {
14101 tree type_domain;
14111 NULL_TREE);
14112 }
14115 }
14117 /* Builds an expression for an indirection through T, simplifying some
14118 cases. */
14120 tree
14122 {
14130 }
14132 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14134 tree
14136 {
14141 else
14143 }
14145 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14146 whose result is ignored. The type of the returned tree need not be
14147 the same as the original expression. */
14149 tree
14151 {
14157 {
14168 else
14174 {
14190 }
14195 }
14196 }
14198 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14200 tree
14202 {
14208 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14209 have to do anything. Only do this when we are not given a const,
14210 because in that case, this check is more expensive than just
14211 doing it. */
14213 {
14218 }
14220 /* If divisor is a power of two, simplify this to bit manipulation. */
14222 {
14224 {
14238 }
14239 else
14240 {
14241 tree t;
14247 }
14248 }
14249 else
14250 {
14255 }
14258 }
14260 /* Likewise, but round down. */
14262 tree
14264 {
14271 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14272 have to do anything. Only do this when we are not given a const,
14273 because in that case, this check is more expensive than just
14274 doing it. */
14276 {
14281 }
14283 /* If divisor is a power of two, simplify this to bit manipulation. */
14285 {
14286 tree t;
14290 }
14291 else
14292 {
14297 }
14300 }
14302 /* Returns the pointer to the base of the object addressed by EXP and
14303 extracts the information about the offset of the access, storing it
14304 to PBITPOS and POFFSET. */
14306 static tree
14309 {
14310 tree core;
14311 machine_mode mode;
14313 HOST_WIDE_INT bitsize;
14317 {
14322 }
14323 else
14324 {
14328 }
14331 }
14333 /* Returns true if addresses of E1 and E2 differ by a constant, false
14334 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14336 bool
14338 {
14352 {
14362 }
14364 {
14365 /* If only one of the offsets is non-constant, the difference cannot
14366 be a constant. */
14368 }
14369 else
14374 }
14376 /* Return OFF converted to a pointer offset type suitable as offset for
14377 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14378 tree
14380 {
14382 }
14384 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14385 tree
14387 {
14390 }
14392 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14393 tree
14395 {
14398 }
14400 /* Return a char pointer for a C string if it is a string constant
14401 or sum of string constant and integer constant. */
14405 {
14406 tree offset_node;
14419 }