| blob | 8a7c93e0459b83a5a131532b9b9d39ec17e3ac74 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2016 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. */
80 #ifndef LOAD_EXTEND_OP
81 #define LOAD_EXTEND_OP(M) UNKNOWN
82 #endif
84 /* Nonzero if we are folding constants inside an initializer; zero
85 otherwise. */
88 /* The following constants represent a bit based encoding of GCC's
89 comparison operators. This encoding simplifies transformations
90 on relational comparison operators, such as AND and OR. */
108 };
148 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
149 Otherwise, return LOC. */
151 static location_t
153 {
156 }
158 /* Similar to protected_set_expr_location, but never modify x in place,
159 if location can and needs to be set, unshare it. */
163 {
169 {
172 }
174 }
175 \f
176 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
177 division and returns the quotient. Otherwise returns
178 NULL_TREE. */
180 tree
182 {
183 widest_int quo;
190 }
191 \f
192 /* This is nonzero if we should defer warnings about undefined
193 overflow. This facility exists because these warnings are a
194 special case. The code to estimate loop iterations does not want
195 to issue any warnings, since it works with expressions which do not
196 occur in user code. Various bits of cleanup code call fold(), but
197 only use the result if it has certain characteristics (e.g., is a
198 constant); that code only wants to issue a warning if the result is
199 used. */
203 /* If a warning about undefined overflow is deferred, this is the
204 warning. Note that this may cause us to turn two warnings into
205 one, but that is fine since it is sufficient to only give one
206 warning per expression. */
210 /* If a warning about undefined overflow is deferred, this is the
211 level at which the warning should be emitted. */
215 /* Start deferring overflow warnings. We could use a stack here to
216 permit nested calls, but at present it is not necessary. */
218 void
220 {
222 }
224 /* Stop deferring overflow warnings. If there is a pending warning,
225 and ISSUE is true, then issue the warning if appropriate. STMT is
226 the statement with which the warning should be associated (used for
227 location information); STMT may be NULL. CODE is the level of the
228 warning--a warn_strict_overflow_code value. This function will use
229 the smaller of CODE and the deferred code when deciding whether to
230 issue the warning. CODE may be zero to mean to always use the
231 deferred code. */
233 void
235 {
237 location_t locus;
242 {
248 }
259 /* Use the smallest code level when deciding to issue the
260 warning. */
269 else
272 }
274 /* Stop deferring overflow warnings, ignoring any deferred
275 warnings. */
277 void
279 {
281 }
283 /* Whether we are deferring overflow warnings. */
285 bool
287 {
289 }
291 /* This is called when we fold something based on the fact that signed
292 overflow is undefined. */
294 void
296 {
298 {
301 {
304 }
305 }
308 }
309 \f
310 /* Return true if the built-in mathematical function specified by CODE
311 is odd, i.e. -f(x) == f(-x). */
313 bool
315 {
317 {
318 CASE_CFN_ASIN:
319 CASE_CFN_ASINH:
320 CASE_CFN_ATAN:
321 CASE_CFN_ATANH:
322 CASE_CFN_CASIN:
323 CASE_CFN_CASINH:
324 CASE_CFN_CATAN:
325 CASE_CFN_CATANH:
326 CASE_CFN_CBRT:
327 CASE_CFN_CPROJ:
328 CASE_CFN_CSIN:
329 CASE_CFN_CSINH:
330 CASE_CFN_CTAN:
331 CASE_CFN_CTANH:
332 CASE_CFN_ERF:
333 CASE_CFN_LLROUND:
334 CASE_CFN_LROUND:
335 CASE_CFN_ROUND:
336 CASE_CFN_SIN:
337 CASE_CFN_SINH:
338 CASE_CFN_TAN:
339 CASE_CFN_TANH:
340 CASE_CFN_TRUNC:
343 CASE_CFN_LLRINT:
344 CASE_CFN_LRINT:
345 CASE_CFN_NEARBYINT:
346 CASE_CFN_RINT:
351 }
353 }
355 /* Check whether we may negate an integer constant T without causing
356 overflow. */
358 bool
360 {
361 tree type;
370 }
372 /* Determine whether an expression T can be cheaply negated using
373 the function negate_expr without introducing undefined overflow. */
375 static bool
377 {
378 tree type;
387 {
392 /* Check that -CST will not overflow type. */
405 /* We want to canonicalize to positive real constants. Pretend
406 that only negative ones can be easily negated. */
414 {
425 }
440 /* -(A + B) -> (-B) - A. */
445 /* -(A + B) -> (-A) - B. */
449 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
460 /* INT_MIN/n * n doesn't overflow while negating one operand it does
461 if n is a power of two. */
470 /* Fall through. */
485 /* In general we can't negate B in A / B, because if A is INT_MIN and
486 B is 1, we may turn this into INT_MIN / -1 which is undefined
487 and actually traps on some architectures. */
496 /* Negate -((double)float) as (double)(-float). */
498 {
502 }
506 /* Negate -f(x) as f(-x). */
512 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
514 {
518 }
523 }
525 }
527 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
528 simplification is possible.
529 If negate_expr_p would return true for T, NULL_TREE will never be
530 returned. */
532 static tree
534 {
536 tree tem;
539 {
540 /* Convert - (~A) to A + 1. */
566 {
571 }
575 {
580 {
584 }
587 }
610 {
611 /* -(A + B) -> (-B) - A. */
615 {
619 }
621 /* -(A + B) -> (-A) - B. */
623 {
627 }
628 }
632 /* - (A - B) -> B - A */
644 /* Fall through. */
648 {
657 }
669 /* In general we can't negate B in A / B, because if A is INT_MIN and
670 B is 1, we may turn this into INT_MIN / -1 which is undefined
671 and actually traps on some architectures. */
683 /* Convert -((double)float) into (double)(-float). */
685 {
689 }
693 /* Negate -f(x) as f(-x). */
696 {
702 }
706 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
708 {
711 {
718 }
719 }
724 }
727 }
729 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
730 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
731 return NULL_TREE. */
733 static tree
735 {
737 location_t loc;
750 }
751 \f
752 /* Split a tree IN into a constant, literal and variable parts that could be
753 combined with CODE to make IN. "constant" means an expression with
754 TREE_CONSTANT but that isn't an actual constant. CODE must be a
755 commutative arithmetic operation. Store the constant part into *CONP,
756 the literal in *LITP and return the variable part. If a part isn't
757 present, set it to null. If the tree does not decompose in this way,
758 return the entire tree as the variable part and the other parts as null.
760 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
761 case, we negate an operand that was subtracted. Except if it is a
762 literal for which we use *MINUS_LITP instead.
764 If NEGATE_P is true, we are negating all of IN, again except a literal
765 for which we use *MINUS_LITP instead. If a variable part is of pointer
766 type, it is negated after converting to TYPE. This prevents us from
767 generating illegal MINUS pointer expression. LOC is the location of
768 the converted variable part.
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. */
834 {
835 /* Convert to TYPE before negating. */
838 }
839 }
842 {
843 /* -X - 1 is folded to ~X, undo that here. */
846 }
849 else
853 {
860 {
861 /* Convert to TYPE before negating. */
864 }
865 }
868 }
870 /* Re-associate trees split by the above function. T1 and T2 are
871 either expressions to associate or null. Return the new
872 expression, if any. LOC is the location of the new expression. If
873 we build an operation, do it in TYPE and with CODE. */
875 static tree
877 {
883 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
884 try to fold this since we will have infinite recursion. But do
885 deal with any NEGATE_EXPRs. */
888 {
890 {
903 }
905 {
908 }
912 }
916 }
917 \f
918 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
919 for use in int_const_binop, size_binop and size_diffop. */
921 static bool
923 {
930 {
939 }
944 }
947 /* Combine two integer constants ARG1 and ARG2 under operation CODE
948 to produce a new constant. Return NULL_TREE if we don't know how
949 to evaluate CODE at compile-time. */
951 static tree
954 {
955 wide_int res;
956 tree t;
964 {
980 {
984 else
986 }
989 /* It's unclear from the C standard whether shifts can overflow.
990 The following code ignores overflow; perhaps a C standard
991 interpretation ruling is needed. */
993 else
1000 {
1004 else
1006 }
1010 else
1089 }
1097 }
1099 tree
1101 {
1103 }
1105 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1106 constant. We assume ARG1 and ARG2 have the same data type, or at least
1107 are the same kind of constant and the same machine mode. Return zero if
1108 combining the constants is not allowed in the current operating mode. */
1110 static tree
1112 {
1113 /* Sanity check for the recursive cases. */
1121 {
1127 }
1130 {
1131 machine_mode mode;
1132 REAL_VALUE_TYPE d1;
1133 REAL_VALUE_TYPE d2;
1134 REAL_VALUE_TYPE value;
1135 REAL_VALUE_TYPE result;
1139 /* The following codes are handled by real_arithmetic. */
1141 {
1152 }
1160 /* Don't perform operation if we honor signaling NaNs and
1161 either operand is a signaling NaN. */
1167 /* Don't perform operation if it would raise a division
1168 by zero exception. */
1174 /* If either operand is a NaN, just return it. Otherwise, set up
1175 for floating-point trap; we return an overflow. */
1177 {
1178 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1179 is off. */
1183 }
1185 {
1186 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1187 is off. */
1191 }
1196 /* Don't constant fold this floating point operation if
1197 the result has overflowed and flag_trapping_math. */
1205 /* Don't constant fold this floating point operation if the
1206 result may dependent upon the run-time rounding mode and
1207 flag_rounding_math is set, or if GCC's software emulation
1208 is unable to accurately represent the result. */
1218 }
1221 {
1222 FIXED_VALUE_TYPE f1;
1223 FIXED_VALUE_TYPE f2;
1224 FIXED_VALUE_TYPE result;
1229 /* The following codes are handled by fixed_arithmetic. */
1231 {
1243 {
1250 }
1255 }
1262 /* Propagate overflow flags. */
1266 }
1269 {
1278 {
1289 mpc_mul);
1303 mpc_div);
1304 /* Fallthru ... */
1310 {
1311 /* Keep this algorithm in sync with
1312 tree-complex.c:expand_complex_div_straight().
1314 Expand complex division to scalars, straightforward algorithm.
1315 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1316 t = br*br + bi*bi
1317 */
1318 tree magsquared
1322 tree t1
1326 tree t2
1333 }
1334 else
1335 {
1336 /* Keep this algorithm in sync with
1337 tree-complex.c:expand_complex_div_wide().
1339 Expand complex division to scalars, modified algorithm to minimize
1340 overflow with wide input ranges. */
1346 {
1347 /* In the TRUE branch, we compute
1348 ratio = br/bi;
1349 div = (br * ratio) + bi;
1350 tr = (ar * ratio) + ai;
1351 ti = (ai * ratio) - ar;
1352 tr = tr / div;
1353 ti = ti / div; */
1364 }
1365 else
1366 {
1367 /* In the FALSE branch, we compute
1368 ratio = d/c;
1369 divisor = (d * ratio) + c;
1370 tr = (b * ratio) + a;
1371 ti = b - (a * ratio);
1372 tr = tr / div;
1373 ti = ti / div; */
1385 }
1386 }
1391 }
1395 }
1399 {
1405 {
1411 /* It is possible that const_binop cannot handle the given
1412 code and return NULL_TREE */
1415 }
1418 }
1420 /* Shifts allow a scalar offset for a vector. */
1423 {
1429 {
1434 /* It is possible that const_binop cannot handle the given
1435 code and return NULL_TREE. */
1438 }
1441 }
1443 }
1445 /* Overload that adds a TYPE parameter to be able to dispatch
1446 to fold_relational_const. */
1448 tree
1450 {
1454 /* ??? Until we make the const_binop worker take the type of the
1455 result as argument put those cases that need it here. */
1457 {
1468 {
1484 {
1490 }
1493 }
1499 {
1524 {
1537 }
1540 }
1543 }
1548 /* Make sure type and arg0 have the same saturating flag. */
1553 }
1555 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1556 Return zero if computing the constants is not possible. */
1558 tree
1560 {
1561 /* Don't perform the operation, other than NEGATE and ABS, if
1562 flag_signaling_nans is on and the operand is a signaling NaN. */
1571 {
1572 CASE_CONVERT:
1579 /* If the source address is 0, and the source address space
1580 cannot have a valid object at 0, fold to dest type null. */
1591 {
1592 /* Can't call fold_negate_const directly here as that doesn't
1593 handle all cases and we might not be able to negate some
1594 constants. */
1599 }
1608 {
1612 }
1618 /* Perform BIT_NOT_EXPR on each element individually. */
1620 {
1622 tree elem;
1627 {
1633 }
1636 }
1658 {
1677 else
1681 {
1685 }
1688 }
1693 {
1707 {
1712 }
1715 {
1719 }
1722 }
1726 }
1729 }
1731 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1732 indicates which particular sizetype to create. */
1734 tree
1736 {
1738 }
1739 \f
1740 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1741 is a tree code. The type of the result is taken from the operands.
1742 Both must be equivalent integer types, ala int_binop_types_match_p.
1743 If the operands are constant, so is the result. */
1745 tree
1747 {
1756 /* Handle the special case of two integer constants faster. */
1758 {
1759 /* And some specific cases even faster than that. */
1761 {
1766 }
1768 {
1771 }
1773 {
1776 }
1778 /* Handle general case of two integer constants. For sizetype
1779 constant calculations we always want to know about overflow,
1780 even in the unsigned case. */
1782 }
1785 }
1787 /* Given two values, either both of sizetype or both of bitsizetype,
1788 compute the difference between the two values. Return the value
1789 in signed type corresponding to the type of the operands. */
1791 tree
1793 {
1795 tree ctype;
1800 /* If the type is already signed, just do the simple thing. */
1808 else
1811 /* If either operand is not a constant, do the conversions to the signed
1812 type and subtract. The hardware will do the right thing with any
1813 overflow in the subtraction. */
1819 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1820 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1821 overflow) and negate (which can't either). Special-case a result
1822 of zero while we're here. */
1828 else
1832 MINUS_EXPR,
1834 }
1835 \f
1836 /* A subroutine of fold_convert_const handling conversions of an
1837 INTEGER_CST to another integer type. */
1839 static tree
1841 {
1842 /* Given an integer constant, make new constant with new type,
1843 appropriately sign-extended or truncated. Use widest_int
1844 so that any extension is done according ARG1's type. */
1848 }
1850 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1851 to an integer type. */
1853 static tree
1855 {
1857 tree t;
1859 /* The following code implements the floating point to integer
1860 conversion rules required by the Java Language Specification,
1861 that IEEE NaNs are mapped to zero and values that overflow
1862 the target precision saturate, i.e. values greater than
1863 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1864 are mapped to INT_MIN. These semantics are allowed by the
1865 C and C++ standards that simply state that the behavior of
1866 FP-to-integer conversion is unspecified upon overflow. */
1868 wide_int val;
1869 REAL_VALUE_TYPE r;
1873 {
1880 }
1882 /* If R is NaN, return zero and show we have an overflow. */
1884 {
1887 }
1889 /* See if R is less than the lower bound or greater than the
1890 upper bound. */
1893 {
1897 {
1900 }
1901 }
1904 {
1907 {
1910 {
1913 }
1914 }
1915 }
1922 }
1924 /* A subroutine of fold_convert_const handling conversions of a
1925 FIXED_CST to an integer type. */
1927 static tree
1929 {
1930 tree t;
1934 /* Right shift FIXED_CST to temp by fbit. */
1938 {
1940 HOST_BITS_PER_DOUBLE_INT,
1943 /* Left shift temp to temp_trunc by fbit. */
1945 HOST_BITS_PER_DOUBLE_INT,
1947 }
1948 else
1949 {
1952 }
1954 /* If FIXED_CST is negative, we need to round the value toward 0.
1955 By checking if the fractional bits are not zero to add 1 to temp. */
1961 /* Given a fixed-point constant, make new constant with new type,
1962 appropriately sign-extended or truncated. */
1970 }
1972 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1973 to another floating point type. */
1975 static tree
1977 {
1978 REAL_VALUE_TYPE value;
1979 tree t;
1981 /* Don't perform the operation if flag_signaling_nans is on
1982 and the operand is a signaling NaN. */
1990 /* If converting an infinity or NAN to a representation that doesn't
1991 have one, set the overflow bit so that we can produce some kind of
1992 error message at the appropriate point if necessary. It's not the
1993 most user-friendly message, but it's better than nothing. */
2000 /* Regular overflow, conversion produced an infinity in a mode that
2001 can't represent them. */
2006 else
2009 }
2011 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2012 to a floating point type. */
2014 static tree
2016 {
2017 REAL_VALUE_TYPE value;
2018 tree t;
2025 }
2027 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2028 to another fixed-point type. */
2030 static tree
2032 {
2033 FIXED_VALUE_TYPE value;
2034 tree t;
2041 /* Propagate overflow flags. */
2045 }
2047 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2048 to a fixed-point type. */
2050 static tree
2052 {
2053 FIXED_VALUE_TYPE value;
2054 tree t;
2056 double_int di;
2063 else
2071 /* Propagate overflow flags. */
2075 }
2077 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2078 to a fixed-point type. */
2080 static tree
2082 {
2083 FIXED_VALUE_TYPE value;
2084 tree t;
2092 /* Propagate overflow flags. */
2096 }
2098 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2099 type TYPE. If no simplification can be done return NULL_TREE. */
2101 static tree
2103 {
2109 {
2116 }
2118 {
2125 }
2127 {
2134 }
2136 {
2139 {
2144 {
2150 }
2152 }
2153 }
2155 }
2157 /* Construct a vector of zero elements of vector type TYPE. */
2159 static tree
2161 {
2162 tree t;
2166 }
2168 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2170 bool
2172 {
2187 {
2203 }
2204 }
2206 /* Convert expression ARG to type TYPE. Used by the middle-end for
2207 simple conversions in preference to calling the front-end's convert. */
2209 tree
2211 {
2213 tree tem;
2224 {
2227 /* Handle conversions between pointers to different address spaces. */
2232 /* fall through */
2237 {
2241 }
2255 {
2259 }
2261 {
2265 }
2267 {
2271 }
2274 {
2292 }
2297 {
2301 }
2304 {
2318 }
2322 {
2331 integer_zero_node));
2333 {
2337 {
2343 }
2351 }
2355 }
2373 }
2374 fold_convert_exit:
2377 }
2378 \f
2379 /* Return false if expr can be assumed not to be an lvalue, true
2380 otherwise. */
2382 static bool
2384 {
2385 /* We only need to wrap lvalue tree codes. */
2387 {
2418 /* Assume the worst for front-end tree codes. */
2422 }
2425 }
2427 /* Return an expr equal to X but certainly not valid as an lvalue. */
2429 tree
2431 {
2432 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2433 us. */
2440 }
2442 /* When pedantic, return an expr equal to X but certainly not valid as a
2443 pedantic lvalue. Otherwise, return X. */
2445 static tree
2447 {
2449 }
2450 \f
2451 /* Given a tree comparison code, return the code that is the logical inverse.
2452 It is generally not safe to do this for floating-point comparisons, except
2453 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2454 ERROR_MARK in this case. */
2456 enum tree_code
2458 {
2464 {
2495 }
2496 }
2498 /* Similar, but return the comparison that results if the operands are
2499 swapped. This is safe for floating-point. */
2501 enum tree_code
2503 {
2505 {
2531 }
2532 }
2535 /* Convert a comparison tree code from an enum tree_code representation
2536 into a compcode bit-based encoding. This function is the inverse of
2537 compcode_to_comparison. */
2539 static enum comparison_code
2541 {
2543 {
2574 }
2575 }
2577 /* Convert a compcode bit-based encoding of a comparison operator back
2578 to GCC's enum tree_code representation. This function is the
2579 inverse of comparison_to_compcode. */
2581 static enum tree_code
2583 {
2585 {
2616 }
2617 }
2619 /* Return a tree for the comparison which is the combination of
2620 doing the AND or OR (depending on CODE) of the two operations LCODE
2621 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2622 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2623 if this makes the transformation invalid. */
2625 tree
2630 {
2637 {
2648 }
2651 {
2652 /* Eliminate unordered comparisons, as well as LTGT and ORD
2653 which are not used unless the mode has NaNs. */
2659 }
2661 {
2662 /* Check that the original operation and the optimized ones will trap
2663 under the same condition. */
2674 /* In a short-circuited boolean expression the LHS might be
2675 such that the RHS, if evaluated, will never trap. For
2676 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2677 if neither x nor y is NaN. (This is a mixed blessing: for
2678 example, the expression above will never trap, hence
2679 optimizing it to x < y would be invalid). */
2684 /* If the comparison was short-circuited, and only the RHS
2685 trapped, we may now generate a spurious trap. */
2690 /* If we changed the conditions that cause a trap, we lose. */
2693 }
2699 else
2700 {
2705 }
2706 }
2707 \f
2708 /* Return nonzero if two operands (typically of the same tree node)
2709 are necessarily equal. FLAGS modifies behavior as follows:
2711 If OEP_ONLY_CONST is set, only return nonzero for constants.
2712 This function tests whether the operands are indistinguishable;
2713 it does not test whether they are equal using C's == operation.
2714 The distinction is important for IEEE floating point, because
2715 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2716 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2718 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2719 even though it may hold multiple values during a function.
2720 This is because a GCC tree node guarantees that nothing else is
2721 executed between the evaluation of its "operands" (which may often
2722 be evaluated in arbitrary order). Hence if the operands themselves
2723 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2724 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2725 unset means assuming isochronic (or instantaneous) tree equivalence.
2726 Unless comparing arbitrary expression trees, such as from different
2727 statements, this flag can usually be left unset.
2729 If OEP_PURE_SAME is set, then pure functions with identical arguments
2730 are considered the same. It is used when the caller has other ways
2731 to ensure that global memory is unchanged in between.
2733 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2734 not values of expressions.
2736 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2737 any operand with side effect. This is unnecesarily conservative in the
2738 case we know that arg0 and arg1 are in disjoint code paths (such as in
2739 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2740 addresses with TREE_CONSTANT flag set so we know that &var == &var
2741 even if var is volatile. */
2743 int
2745 {
2746 /* When checking, verify at the outermost operand_equal_p call that
2747 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2748 hash value. */
2750 {
2752 {
2754 {
2761 }
2763 }
2764 else
2766 }
2768 /* If either is ERROR_MARK, they aren't equal. */
2774 /* Similar, if either does not have a type (like a released SSA name),
2775 they aren't equal. */
2779 /* We cannot consider pointers to different address space equal. */
2786 /* Check equality of integer constants before bailing out due to
2787 precision differences. */
2789 {
2790 /* Address of INTEGER_CST is not defined; check that we did not forget
2791 to drop the OEP_ADDRESS_OF flags. */
2794 }
2797 {
2798 /* If both types don't have the same signedness, then we can't consider
2799 them equal. We must check this before the STRIP_NOPS calls
2800 because they may change the signedness of the arguments. As pointers
2801 strictly don't have a signedness, require either two pointers or
2802 two non-pointers as well. */
2808 /* If both types don't have the same precision, then it is not safe
2809 to strip NOPs. */
2816 }
2817 #if 0
2818 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2819 sanity check once the issue is solved. */
2820 else
2821 /* Addresses of conversions and SSA_NAMEs (and many other things)
2822 are not defined. Check that we did not forget to drop the
2823 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2826 #endif
2828 /* In case both args are comparisons but with different comparison
2829 code, try to swap the comparison operands of one arg to produce
2830 a match and compare that variant. */
2834 {
2842 }
2845 {
2846 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2848 ;
2850 {
2851 /* If we are interested in comparing addresses ignore
2852 MEM_REF wrappings of the base that can appear just for
2853 TBAA reasons. */
2867 }
2868 else
2870 }
2872 /* When not checking adddresses, this is needed for conversions and for
2873 COMPONENT_REF. Might as well play it safe and always test this. */
2880 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2881 We don't care about side effects in that case because the SAVE_EXPR
2882 takes care of that for us. In all other cases, two expressions are
2883 equal if they have no side effects. If we have two identical
2884 expressions with side effects that should be treated the same due
2885 to the only side effects being identical SAVE_EXPR's, that will
2886 be detected in the recursive calls below.
2887 If we are taking an invariant address of two identical objects
2888 they are necessarily equal as well. */
2895 /* Next handle constant cases, those for which we can return 1 even
2896 if ONLY_CONST is set. */
2899 {
2913 {
2914 /* If we do not distinguish between signed and unsigned zero,
2915 consider them equal. */
2918 }
2922 {
2929 {
2933 }
2935 }
2939 flags)
2941 flags));
2952 flags | OEP_ADDRESS_OF
2955 /* In GIMPLE empty constructors are allowed in initializers of
2956 aggregates. */
2961 }
2966 /* Define macros to test an operand from arg0 and arg1 for equality and a
2967 variant that allows null and views null as being different from any
2968 non-null value. In the latter case, if either is null, the both
2969 must be; otherwise, do the normal comparison. */
2970 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2971 TREE_OPERAND (arg1, N), flags)
2973 #define OP_SAME_WITH_NULL(N) \
2974 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2975 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2978 {
2980 /* Two conversions are equal only if signedness and modes match. */
2982 {
2983 CASE_CONVERT:
2991 }
3001 /* For commutative ops, allow the other order. */
3009 /* If either of the pointer (or reference) expressions we are
3010 dereferencing contain a side effect, these cannot be equal,
3011 but their addresses can be. */
3018 {
3028 /* Require the same offset. */
3034 /* Fallthru. */
3042 {
3043 /* Require equal access sizes */
3049 flags)))
3051 /* Verify that access happens in similar types. */
3054 /* Verify that accesses are TBAA compatible. */
3063 /* Verify that alignment is compatible. */
3067 }
3070 /* TARGET_MEM_REF require equal extra operands. */
3081 /* Compare the array index by value if it is constant first as we
3082 may have different types but same value here. */
3088 /* Compare low bound and element size as with OEP_ADDRESS_OF
3089 we have to account for the offset of the ref. */
3094 array_ref_low_bound
3098 array_ref_element_size
3100 flags))));
3103 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3104 may be NULL when we're called to compare MEM_EXPRs. */
3119 }
3123 {
3125 /* Be sure we pass right ADDRESS_OF flag. */
3143 /* The multiplcation operands are commutative. */
3144 /* FALLTHRU */
3152 /* Otherwise take into account this is a commutative operation. */
3170 }
3174 {
3178 /* If not both CALL_EXPRs are either internal or normal function
3179 functions, then they are not equal. */
3182 {
3183 /* If the CALL_EXPRs call different internal functions, then they
3184 are not equal. */
3187 }
3188 else
3189 {
3190 /* If the CALL_EXPRs call different functions, then they are not
3191 equal. */
3193 flags))
3195 }
3197 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3198 {
3202 else
3206 }
3208 /* Now see if all the arguments are the same. */
3209 {
3220 /* If we get here and both argument lists are exhausted
3221 then the CALL_EXPRs are equal. */
3223 }
3226 }
3229 /* Consider __builtin_sqrt equal to sqrt. */
3237 {
3238 /* In GIMPLE constructors are used only to build vectors from
3239 elements. Individual elements in the constructor must be
3240 indexed in increasing order and form an initial sequence.
3242 We make no effort to compare constructors in generic.
3243 (see sem_variable::equals in ipa-icf which can do so for
3244 constants). */
3249 /* Be sure that vectors constructed have the same representation.
3250 We only tested element precision and modes to match.
3251 Vectors may be BLKmode and thus also check that the number of
3252 parts match. */
3265 {
3270 /* In GIMPLE the indexes can be either NULL or matching i.
3271 Double check this so we won't get false
3272 positives for GENERIC. */
3280 }
3282 }
3287 }
3289 #undef OP_SAME
3290 #undef OP_SAME_WITH_NULL
3291 }
3292 \f
3293 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3294 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3296 When in doubt, return 0. */
3298 static int
3300 {
3312 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3313 and see if the inner values are the same. This removes any
3314 signedness comparison, which doesn't matter here. */
3321 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3322 actual comparison operand, ARG0.
3324 First throw away any conversions to wider types
3325 already present in the operands. */
3334 {
3337 /* Make sure shorter operand is extended the right way
3338 to match the longer operand. */
3344 }
3347 }
3348 \f
3349 /* See if ARG is an expression that is either a comparison or is performing
3350 arithmetic on comparisons. The comparisons must only be comparing
3351 two different values, which will be stored in *CVAL1 and *CVAL2; if
3352 they are nonzero it means that some operands have already been found.
3353 No variables may be used anywhere else in the expression except in the
3354 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3355 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3357 If this is true, return 1. Otherwise, return zero. */
3359 static int
3361 {
3365 /* We can handle some of the tcc_expression cases here. */
3375 {
3376 /* If we've already found a CVAL1 or CVAL2, this expression is
3377 two complex to handle. */
3383 }
3386 {
3409 /* First see if we can handle the first operand, then the second. For
3410 the second operand, we know *CVAL1 can't be zero. It must be that
3411 one side of the comparison is each of the values; test for the
3412 case where this isn't true by failing if the two operands
3413 are the same. */
3422 ;
3426 ;
3427 else
3431 ;
3435 ;
3436 else
3443 }
3444 }
3445 \f
3446 /* ARG is a tree that is known to contain just arithmetic operations and
3447 comparisons. Evaluate the operations in the tree substituting NEW0 for
3448 any occurrence of OLD0 as an operand of a comparison and likewise for
3449 NEW1 and OLD1. */
3451 static tree
3454 {
3459 /* We can handle some of the tcc_expression cases here. */
3467 {
3482 {
3501 }
3502 /* Fall through - ??? */
3505 {
3509 /* We need to check both for exact equality and tree equality. The
3510 former will be true if the operand has a side-effect. In that
3511 case, we know the operand occurred exactly once. */
3524 }
3528 }
3529 }
3530 \f
3531 /* Return a tree for the case when the result of an expression is RESULT
3532 converted to TYPE and OMITTED was previously an operand of the expression
3533 but is now not needed (e.g., we folded OMITTED * 0).
3535 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3536 the conversion of RESULT to TYPE. */
3538 tree
3540 {
3543 /* If the resulting operand is an empty statement, just return the omitted
3544 statement casted to void. */
3554 }
3556 /* Return a tree for the case when the result of an expression is RESULT
3557 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3558 of the expression but are now not needed.
3560 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3561 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3562 evaluated before OMITTED2. Otherwise, if neither has side effects,
3563 just do the conversion of RESULT to TYPE. */
3565 tree
3568 {
3577 }
3579 \f
3580 /* Return a simplified tree node for the truth-negation of ARG. This
3581 never alters ARG itself. We assume that ARG is an operation that
3582 returns a truth value (0 or 1).
3584 FIXME: one would think we would fold the result, but it causes
3585 problems with the dominator optimizer. */
3587 static tree
3589 {
3594 /* If this is a comparison, we can simply invert it, except for
3595 floating-point non-equality comparisons, in which case we just
3596 enclose a TRUTH_NOT_EXPR around what we have. */
3599 {
3602 && flag_trapping_math
3616 }
3619 {
3638 /* Here we can invert either operand. We invert the first operand
3639 unless the second operand is a TRUTH_NOT_EXPR in which case our
3640 result is the XOR of the first operand with the inside of the
3641 negation of the second operand. */
3646 else
3669 {
3676 /* A COND_EXPR may have a throw as one operand, which
3677 then has void type. Just leave void operands
3678 as they are. */
3684 }
3696 CASE_CONVERT:
3700 /* ... fall through ... */
3722 }
3723 }
3725 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3726 assume that ARG is an operation that returns a truth value (0 or 1
3727 for scalars, 0 or -1 for vectors). Return the folded expression if
3728 folding is successful. Otherwise, return NULL_TREE. */
3730 static tree
3732 {
3735 ? BIT_NOT_EXPR
3738 }
3740 /* Return a simplified tree node for the truth-negation of ARG. This
3741 never alters ARG itself. We assume that ARG is an operation that
3742 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3744 tree
3746 {
3752 ? BIT_NOT_EXPR
3755 }
3757 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3758 with code CODE. This optimization is unsafe. */
3759 static tree
3762 {
3766 /* (A / C) +- (B / C) -> (A +- B) / C. */
3776 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3781 {
3793 }
3796 }
3797 \f
3798 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3799 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3800 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3801 is the original memory reference used to preserve the alias set of
3802 the access. */
3804 static tree
3808 {
3814 build_int_cst
3818 {
3825 }
3840 }
3842 /* Optimize a bit-field compare.
3844 There are two cases: First is a compare against a constant and the
3845 second is a comparison of two items where the fields are at the same
3846 bit position relative to the start of a chunk (byte, halfword, word)
3847 large enough to contain it. In these cases we can avoid the shift
3848 implicit in bitfield extractions.
3850 For constants, we emit a compare of the shifted constant with the
3851 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3852 compared. For two fields at the same position, we do the ANDs with the
3853 similar mask and compare the result of the ANDs.
3855 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3856 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3857 are the left and right operands of the comparison, respectively.
3859 If the optimization described above can be done, we return the resulting
3860 tree. Otherwise we return zero. */
3862 static tree
3865 {
3868 tree unsigned_type;
3875 tree mask;
3876 tree offset;
3878 /* Get all the information about the extractions being done. If the bit size
3879 if the same as the size of the underlying object, we aren't doing an
3880 extraction at all and so can do nothing. We also don't want to
3881 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3882 then will no longer be able to replace it. */
3891 else
3892 {
3893 /* If this is not a constant, we can only do something if bit positions,
3894 sizes, signedness and storage order are the same. */
3895 rinner
3903 }
3905 /* See if we can find a mode to refer to this field. We should be able to,
3906 but fail if we can't. */
3915 /* Set signed and unsigned types of the precision of this mode for the
3916 shifts below. */
3919 /* Compute the bit position and size for the new reference and our offset
3920 within it. If the new reference is the same size as the original, we
3921 won't optimize anything, so return zero. */
3931 /* Make the mask to be used against the extracted field. */
3938 /* If not comparing with constant, just rework the comparison
3939 and return. */
3943 unsigned_type,
3946 mask),
3949 unsigned_type,
3952 mask));
3954 /* Otherwise, we are handling the constant case. See if the constant is too
3955 big for the field. Warn and return a tree for 0 (false) if so. We do
3956 this not only for its own sake, but to avoid having to test for this
3957 error case below. If we didn't, we might generate wrong code.
3959 For unsigned fields, the constant shifted right by the field length should
3960 be all zero. For signed fields, the high-order bits should agree with
3961 the sign bit. */
3964 {
3966 {
3970 }
3971 }
3972 else
3973 {
3976 {
3980 }
3981 }
3983 /* Single-bit compares should always be against zero. */
3985 {
3988 }
3990 /* Make a new bitfield reference, shift the constant over the
3991 appropriate number of bits and mask it with the computed mask
3992 (in case this was a signed field). If we changed it, make a new one. */
4000 mask);
4005 }
4006 \f
4007 /* Subroutine for fold_truth_andor_1: decode a field reference.
4009 If EXP is a comparison reference, we return the innermost reference.
4011 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4012 set to the starting bit number.
4014 If the innermost field can be completely contained in a mode-sized
4015 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4017 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4018 otherwise it is not changed.
4020 *PUNSIGNEDP is set to the signedness of the field.
4022 *PREVERSEP is set to the storage order of the field.
4024 *PMASK is set to the mask used. This is either contained in a
4025 BIT_AND_EXPR or derived from the width of the field.
4027 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4029 Return 0 if this is not a component reference or is one that we can't
4030 do anything with. */
4032 static tree
4037 {
4042 tree unsigned_type;
4045 /* All the optimizations using this function assume integer fields.
4046 There are problems with FP fields since the type_for_size call
4047 below can fail for, e.g., XFmode. */
4051 /* We are interested in the bare arrangement of bits, so strip everything
4052 that doesn't affect the machine mode. However, record the type of the
4053 outermost expression if it may matter below. */
4060 {
4066 }
4077 /* If the number of bits in the reference is the same as the bitsize of
4078 the outer type, then the outer type gives the signedness. Otherwise
4079 (in case of a small bitfield) the signedness is unchanged. */
4083 /* Compute the mask to access the bitfield. */
4092 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4100 }
4102 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4103 bit positions and MASK is SIGNED. */
4105 static int
4107 {
4111 /* If this function returns true when the type of the mask is
4112 UNSIGNED, then there will be errors. In particular see
4113 gcc.c-torture/execute/990326-1.c. There does not appear to be
4114 any documentation paper trail as to why this is so. But the pre
4115 wide-int worked with that restriction and it has been preserved
4116 here. */
4121 }
4123 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4124 represents the sign bit of EXP's type. If EXP represents a sign
4125 or zero extension, also test VAL against the unextended type.
4126 The return value is the (sub)expression whose sign bit is VAL,
4127 or NULL_TREE otherwise. */
4129 tree
4131 {
4133 tree t;
4135 /* Tree EXP must have an integral type. */
4140 /* Tree VAL must be an integer constant. */
4149 /* Handle extension from a narrower type. */
4155 }
4157 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4158 to be evaluated unconditionally. */
4160 static int
4162 {
4163 /* Strip any conversions that don't change the machine mode. */
4172 /* Don't regard global variables as simple. They may be
4173 allocated in ways unknown to the compiler (shared memory,
4174 #pragma weak, etc). */
4177 /* Weakrefs are not safe to be read, since they can be NULL.
4178 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4179 have DECL_WEAK flag set. */
4181 /* Loading a static variable is unduly expensive, but global
4182 registers aren't expensive. */
4184 }
4186 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4187 to be evaluated unconditionally.
4188 I addition to simple_operand_p, we assume that comparisons, conversions,
4189 and logic-not operations are simple, if their operands are simple, too. */
4191 static bool
4193 {
4213 }
4215 \f
4216 /* The following functions are subroutines to fold_range_test and allow it to
4217 try to change a logical combination of comparisons into a range test.
4219 For example, both
4220 X == 2 || X == 3 || X == 4 || X == 5
4221 and
4222 X >= 2 && X <= 5
4223 are converted to
4224 (unsigned) (X - 2) <= 3
4226 We describe each set of comparisons as being either inside or outside
4227 a range, using a variable named like IN_P, and then describe the
4228 range with a lower and upper bound. If one of the bounds is omitted,
4229 it represents either the highest or lowest value of the type.
4231 In the comments below, we represent a range by two numbers in brackets
4232 preceded by a "+" to designate being inside that range, or a "-" to
4233 designate being outside that range, so the condition can be inverted by
4234 flipping the prefix. An omitted bound is represented by a "-". For
4235 example, "- [-, 10]" means being outside the range starting at the lowest
4236 possible value and ending at 10, in other words, being greater than 10.
4237 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4238 always false.
4240 We set up things so that the missing bounds are handled in a consistent
4241 manner so neither a missing bound nor "true" and "false" need to be
4242 handled using a special case. */
4244 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4245 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4246 and UPPER1_P are nonzero if the respective argument is an upper bound
4247 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4248 must be specified for a comparison. ARG1 will be converted to ARG0's
4249 type if both are specified. */
4251 static tree
4254 {
4255 tree tem;
4259 /* If neither arg represents infinity, do the normal operation.
4260 Else, if not a comparison, return infinity. Else handle the special
4261 comparison rules. Note that most of the cases below won't occur, but
4262 are handled for consistency. */
4265 {
4270 }
4275 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4276 for neither. In real maths, we cannot assume open ended ranges are
4277 the same. But, this is computer arithmetic, where numbers are finite.
4278 We can therefore make the transformation of any unbounded range with
4279 the value Z, Z being greater than any representable number. This permits
4280 us to treat unbounded ranges as equal. */
4284 {
4305 }
4308 }
4309 \f
4310 /* Helper routine for make_range. Perform one step for it, return
4311 new expression if the loop should continue or NULL_TREE if it should
4312 stop. */
4314 tree
4318 {
4324 {
4326 /* We can only do something if the range is testing for zero. */
4335 /* We can only do something if the range is testing for zero
4336 and if the second operand is an integer constant. Note that
4337 saying something is "in" the range we make is done by
4338 complementing IN_P since it will set in the initial case of
4339 being not equal to zero; "out" is leaving it alone. */
4346 {
4367 }
4369 /* If this is an unsigned comparison, we also know that EXP is
4370 greater than or equal to zero. We base the range tests we make
4371 on that fact, so we record it here so we can parse existing
4372 range tests. We test arg0_type since often the return type
4373 of, e.g. EQ_EXPR, is boolean. */
4375 {
4379 NULL_TREE))
4384 /* If the high bound is missing, but we have a nonzero low
4385 bound, reverse the range so it goes from zero to the low bound
4386 minus 1. */
4388 {
4393 }
4394 }
4402 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4403 low and high are non-NULL, then normalize will DTRT. */
4406 {
4411 }
4413 /* (-x) IN [a,b] -> x in [-b, -a] */
4425 /* ~ X -> -X - 1 */
4434 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4435 move a constant to the other side. */
4440 /* If EXP is signed, any overflow in the computation is undefined,
4441 so we don't worry about it so long as our computations on
4442 the bounds don't overflow. For unsigned, overflow is defined
4443 and this is exactly the right thing. */
4455 normalize:
4456 /* Check for an unsigned range which has wrapped around the maximum
4457 value thus making n_high < n_low, and normalize it. */
4459 {
4465 /* If the range is of the form +/- [ x+1, x ], we won't
4466 be able to normalize it. But then, it represents the
4467 whole range or the empty set, so make it
4468 +/- [ -, - ]. */
4472 else
4474 }
4475 else
4483 CASE_CONVERT:
4501 /* If we're converting arg0 from an unsigned type, to exp,
4502 a signed type, we will be doing the comparison as unsigned.
4503 The tests above have already verified that LOW and HIGH
4504 are both positive.
4506 So we have to ensure that we will handle large unsigned
4507 values the same way that the current signed bounds treat
4508 negative values. */
4511 {
4512 tree high_positive;
4513 tree equiv_type;
4514 /* For fixed-point modes, we need to pass the saturating flag
4515 as the 2nd parameter. */
4517 equiv_type
4520 else
4521 equiv_type
4524 /* A range without an upper bound is, naturally, unbounded.
4525 Since convert would have cropped a very large value, use
4526 the max value for the destination type. */
4527 high_positive
4534 high_positive),
4537 /* If the low bound is specified, "and" the range with the
4538 range for which the original unsigned value will be
4539 positive. */
4541 {
4544 integer_zero_node),
4545 high_positive))
4549 }
4550 else
4551 {
4552 /* Otherwise, "or" the range with the range of the input
4553 that will be interpreted as negative. */
4556 integer_zero_node),
4557 high_positive))
4561 }
4562 }
4571 }
4572 }
4574 /* Given EXP, a logical expression, set the range it is testing into
4575 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4576 actually being tested. *PLOW and *PHIGH will be made of the same
4577 type as the returned expression. If EXP is not a comparison, we
4578 will most likely not be returning a useful value and range. Set
4579 *STRICT_OVERFLOW_P to true if the return value is only valid
4580 because signed overflow is undefined; otherwise, do not change
4581 *STRICT_OVERFLOW_P. */
4583 tree
4586 {
4594 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4595 and see if we can refine the range. Some of the cases below may not
4596 happen, but it doesn't seem worth worrying about this. We "continue"
4597 the outer loop when we've changed something; otherwise we "break"
4598 the switch, which will "break" the while. */
4604 {
4610 {
4618 }
4627 }
4629 /* If EXP is a constant, we can evaluate whether this is true or false. */
4631 {
4638 }
4642 }
4643 \f
4644 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4645 type, TYPE, return an expression to test if EXP is in (or out of, depending
4646 on IN_P) the range. Return 0 if the test couldn't be created. */
4648 tree
4651 {
4654 /* Disable this optimization for function pointer expressions
4655 on targets that require function pointer canonicalization. */
4662 {
4668 }
4686 {
4688 {
4692 }
4694 }
4696 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4698 {
4702 {
4704 {
4707 etype
4709 else
4712 }
4715 }
4716 }
4718 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4719 This requires wrap-around arithmetics for the type of the expression.
4720 First make sure that arithmetics in this type is valid, then make sure
4721 that it wraps around. */
4727 {
4730 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4731 for the type in question, as we rely on this here. */
4741 else
4743 }
4753 {
4755 {
4760 }
4762 }
4770 }
4771 \f
4772 /* Return the predecessor of VAL in its type, handling the infinite case. */
4774 static tree
4776 {
4782 else
4785 }
4787 /* Return the successor of VAL in its type, handling the infinite case. */
4789 static tree
4791 {
4797 else
4800 }
4802 /* Given two ranges, see if we can merge them into one. Return 1 if we
4803 can, 0 if we can't. Set the output range into the specified parameters. */
4805 bool
4808 {
4812 tree tem;
4822 /* Make range 0 be the range that starts first, or ends last if they
4823 start at the same value. Swap them if it isn't. */
4826 || (lowequal
4829 {
4833 }
4835 /* Now flag two cases, whether the ranges are disjoint or whether the
4836 second range is totally subsumed in the first. Note that the tests
4837 below are simplified by the ones above. */
4843 /* We now have four cases, depending on whether we are including or
4844 excluding the two ranges. */
4846 {
4847 /* If they don't overlap, the result is false. If the second range
4848 is a subset it is the result. Otherwise, the range is from the start
4849 of the second to the end of the first. */
4854 else
4856 }
4859 {
4860 /* If they don't overlap, the result is the first range. If they are
4861 equal, the result is false. If the second range is a subset of the
4862 first, and the ranges begin at the same place, we go from just after
4863 the end of the second range to the end of the first. If the second
4864 range is not a subset of the first, or if it is a subset and both
4865 ranges end at the same place, the range starts at the start of the
4866 first range and ends just before the second range.
4867 Otherwise, we can't describe this as a single range. */
4873 {
4878 {
4879 /* We are in the weird situation where high0 > high1 but
4880 high1 has no successor. Punt. */
4882 }
4883 }
4885 {
4890 {
4891 /* low0 < low1 but low1 has no predecessor. Punt. */
4893 }
4894 }
4895 else
4897 }
4900 {
4901 /* If they don't overlap, the result is the second range. If the second
4902 is a subset of the first, the result is false. Otherwise,
4903 the range starts just after the first range and ends at the
4904 end of the second. */
4909 else
4910 {
4915 {
4916 /* high1 > high0 but high0 has no successor. Punt. */
4918 }
4919 }
4920 }
4922 else
4923 {
4924 /* The case where we are excluding both ranges. Here the complex case
4925 is if they don't overlap. In that case, the only time we have a
4926 range is if they are adjacent. If the second is a subset of the
4927 first, the result is the first. Otherwise, the range to exclude
4928 starts at the beginning of the first range and ends at the end of the
4929 second. */
4931 {
4936 else
4937 {
4938 /* Canonicalize - [min, x] into - [-, x]. */
4941 {
4946 /* FALLTHROUGH */
4959 }
4961 /* Canonicalize - [x, max] into - [x, -]. */
4964 {
4969 /* FALLTHROUGH */
4985 }
4987 /* The ranges might be also adjacent between the maximum and
4988 minimum values of the given type. For
4989 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4990 return + [x + 1, y - 1]. */
4992 {
4999 }
5000 else
5002 }
5003 }
5006 else
5008 }
5012 }
5013 \f
5015 /* Subroutine of fold, looking inside expressions of the form
5016 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5017 of the COND_EXPR. This function is being used also to optimize
5018 A op B ? C : A, by reversing the comparison first.
5020 Return a folded expression whose code is not a COND_EXPR
5021 anymore, or NULL_TREE if no folding opportunity is found. */
5023 static tree
5026 {
5031 tree tem;
5036 /* If we have A op 0 ? A : -A, consider applying the following
5037 transformations:
5039 A == 0? A : -A same as -A
5040 A != 0? A : -A same as A
5041 A >= 0? A : -A same as abs (A)
5042 A > 0? A : -A same as abs (A)
5043 A <= 0? A : -A same as -abs (A)
5044 A < 0? A : -A same as -abs (A)
5046 None of these transformations work for modes with signed
5047 zeros. If A is +/-0, the first two transformations will
5048 change the sign of the result (from +0 to -0, or vice
5049 versa). The last four will fix the sign of the result,
5050 even though the original expressions could be positive or
5051 negative, depending on the sign of A.
5053 Note that all these transformations are correct if A is
5054 NaN, since the two alternatives (A and -A) are also NaNs. */
5061 /* In the case that A is of the form X-Y, '-A' (arg2) may
5062 have already been folded to Y-X, check for that. */
5070 {
5084 /* Fall through. */
5104 }
5106 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5107 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5108 both transformations are correct when A is NaN: A != 0
5109 is then true, and A == 0 is false. */
5113 {
5118 }
5120 /* Try some transformations of A op B ? A : B.
5122 A == B? A : B same as B
5123 A != B? A : B same as A
5124 A >= B? A : B same as max (A, B)
5125 A > B? A : B same as max (B, A)
5126 A <= B? A : B same as min (A, B)
5127 A < B? A : B same as min (B, A)
5129 As above, these transformations don't work in the presence
5130 of signed zeros. For example, if A and B are zeros of
5131 opposite sign, the first two transformations will change
5132 the sign of the result. In the last four, the original
5133 expressions give different results for (A=+0, B=-0) and
5134 (A=-0, B=+0), but the transformed expressions do not.
5136 The first two transformations are correct if either A or B
5137 is a NaN. In the first transformation, the condition will
5138 be false, and B will indeed be chosen. In the case of the
5139 second transformation, the condition A != B will be true,
5140 and A will be chosen.
5142 The conversions to max() and min() are not correct if B is
5143 a number and A is not. The conditions in the original
5144 expressions will be false, so all four give B. The min()
5145 and max() versions would give a NaN instead. */
5148 /* Avoid these transformations if the COND_EXPR may be used
5149 as an lvalue in the C++ front-end. PR c++/19199. */
5150 && (in_gimple_form
5156 {
5161 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
5163 {
5167 }
5170 {
5179 /* In C++ a ?: expression can be an lvalue, so put the
5180 operand which will be used if they are equal first
5181 so that we can convert this back to the
5182 corresponding COND_EXPR. */
5184 {
5193 }
5200 {
5209 }
5224 }
5225 }
5227 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5228 we might still be able to simplify this. For example,
5229 if C1 is one less or one more than C2, this might have started
5230 out as a MIN or MAX and been transformed by this function.
5231 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5237 {
5241 /* We can replace A with C1 in this case. */
5246 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
5247 MIN_EXPR, to preserve the signedness of the comparison. */
5249 OEP_ONLY_CONST)
5253 OEP_ONLY_CONST))
5254 {
5257 arg2));
5260 }
5264 /* If C1 is C2 - 1, this is min(A, C2), with the same care
5265 as above. */
5267 OEP_ONLY_CONST)
5271 OEP_ONLY_CONST))
5272 {
5275 arg2));
5278 }
5282 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
5283 MAX_EXPR, to preserve the signedness of the comparison. */
5285 OEP_ONLY_CONST)
5289 OEP_ONLY_CONST))
5290 {
5293 arg2));
5295 }
5299 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
5301 OEP_ONLY_CONST)
5305 OEP_ONLY_CONST))
5306 {
5309 arg2));
5311 }
5317 }
5320 }
5323 \f
5324 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5325 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5326 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5327 false) >= 2)
5328 #endif
5330 /* EXP is some logical combination of boolean tests. See if we can
5331 merge it into some range test. Return the new tree if so. */
5333 static tree
5336 {
5352 /* If this is an OR operation, invert both sides; we will invert
5353 again at the end. */
5357 /* If both expressions are the same, if we can merge the ranges, and we
5358 can build the range test, return it or it inverted. If one of the
5359 ranges is always true or always false, consider it to be the same
5360 expression as the other. */
5368 {
5372 }
5374 /* On machines where the branch cost is expensive, if this is a
5375 short-circuited branch and the underlying object on both sides
5376 is the same, make a non-short-circuit operation. */
5382 {
5383 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5384 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5385 which cases we can't do this. */
5393 {
5402 {
5405 WARN_STRICT_OVERFLOW_COMPARISON);
5409 }
5410 }
5411 }
5414 }
5415 \f
5416 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5417 bit value. Arrange things so the extra bits will be set to zero if and
5418 only if C is signed-extended to its full width. If MASK is nonzero,
5419 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5421 static tree
5423 {
5426 tree temp;
5431 /* We work by getting just the sign bit into the low-order bit, then
5432 into the high-order bit, then sign-extend. We then XOR that value
5433 with C. */
5436 /* We must use a signed type in order to get an arithmetic right shift.
5437 However, we must also avoid introducing accidental overflows, so that
5438 a subsequent call to integer_zerop will work. Hence we must
5439 do the type conversion here. At this point, the constant is either
5440 zero or one, and the conversion to a signed type can never overflow.
5441 We could get an overflow if this conversion is done anywhere else. */
5450 /* If necessary, convert the type back to match the type of C. */
5455 }
5456 \f
5457 /* For an expression that has the form
5458 (A && B) || ~B
5459 or
5460 (A || B) && ~B,
5461 we can drop one of the inner expressions and simplify to
5462 A || ~B
5463 or
5464 A && ~B
5465 LOC is the location of the resulting expression. OP is the inner
5466 logical operation; the left-hand side in the examples above, while CMPOP
5467 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5468 removing a condition that guards another, as in
5469 (A != NULL && A->...) || A == NULL
5470 which we must not transform. If RHS_ONLY is true, only eliminate the
5471 right-most operand of the inner logical operation. */
5473 static tree
5476 {
5494 {
5497 {
5500 }
5501 }
5503 {
5506 {
5509 }
5510 }
5525 }
5527 /* Find ways of folding logical expressions of LHS and RHS:
5528 Try to merge two comparisons to the same innermost item.
5529 Look for range tests like "ch >= '0' && ch <= '9'".
5530 Look for combinations of simple terms on machines with expensive branches
5531 and evaluate the RHS unconditionally.
5533 For example, if we have p->a == 2 && p->b == 4 and we can make an
5534 object large enough to span both A and B, we can do this with a comparison
5535 against the object ANDed with the a mask.
5537 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5538 operations to do this with one comparison.
5540 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5541 function and the one above.
5543 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5544 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5546 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5547 two operands.
5549 We return the simplified tree or 0 if no optimization is possible. */
5551 static tree
5554 {
5555 /* If this is the "or" of two comparisons, we can do something if
5556 the comparisons are NE_EXPR. If this is the "and", we can do something
5557 if the comparisons are EQ_EXPR. I.e.,
5558 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5560 WANTED_CODE is this operation code. For single bit fields, we can
5561 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5562 comparison for one-bit fields. */
5583 /* Start by getting the comparison codes. Fail if anything is volatile.
5584 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5585 it were surrounded with a NE_EXPR. */
5594 {
5598 }
5601 {
5605 }
5616 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5619 {
5622 {
5627 }
5630 {
5636 }
5637 }
5642 /* If the RHS can be evaluated unconditionally and its operands are
5643 simple, it wins to evaluate the RHS unconditionally on machines
5644 with expensive branches. In this case, this isn't a comparison
5645 that can be merged. */
5652 {
5653 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5664 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5674 }
5676 /* See if the comparisons can be merged. Then get all the parameters for
5677 each side. */
5702 /* It must be true that the inner operation on the lhs of each
5703 comparison must be the same if we are to be able to do anything.
5704 Then see if we have constants. If not, the same must be true for
5705 the rhs's. */
5714 {
5717 }
5722 else
5725 /* If either comparison code is not correct for our logical operation,
5726 fail. However, we can convert a one-bit comparison against zero into
5727 the opposite comparison against that bit being set in the field. */
5731 {
5733 {
5734 /* Make the left operand unsigned, since we are only interested
5735 in the value of one bit. Otherwise we are doing the wrong
5736 thing below. */
5739 }
5740 else
5742 }
5744 /* This is analogous to the code for l_const above. */
5746 {
5748 {
5751 }
5752 else
5754 }
5756 /* See if we can find a mode that contains both fields being compared on
5757 the left. If we can't, fail. Otherwise, update all constants and masks
5758 to be relative to a field of that size. */
5763 volatilep);
5773 {
5776 }
5784 {
5791 {
5795 }
5796 }
5798 {
5805 {
5809 }
5810 }
5812 /* If the right sides are not constant, do the same for it. Also,
5813 disallow this optimization if a size or signedness mismatch occurs
5814 between the left and right sides. */
5816 {
5819 /* Make sure the two fields on the right
5820 correspond to the left without being swapped. */
5828 volatilep);
5838 {
5841 }
5850 /* Make a mask that corresponds to both fields being compared.
5851 Do this for both items being compared. If the operands are the
5852 same size and the bits being compared are in the same position
5853 then we can do this by masking both and comparing the masked
5854 results. */
5858 {
5872 }
5874 /* There is still another way we can do something: If both pairs of
5875 fields being compared are adjacent, we may be able to make a wider
5876 field containing them both.
5878 Note that we still must mask the lhs/rhs expressions. Furthermore,
5879 the mask must be shifted to account for the shift done by
5880 make_bit_field_ref. */
5885 {
5886 tree type;
5902 /* Convert to the smaller type before masking out unwanted bits. */
5905 {
5907 {
5911 }
5913 {
5917 }
5918 }
5927 }
5930 }
5932 /* Handle the case of comparisons with constants. If there is something in
5933 common between the masks, those bits of the constants must be the same.
5934 If not, the condition is always false. Test for this to avoid generating
5935 incorrect code below. */
5940 {
5942 {
5945 }
5946 else
5947 {
5950 }
5951 }
5953 /* Construct the expression we will return. First get the component
5954 reference we will make. Unless the mask is all ones the width of
5955 that field, perform the mask operation. Then compare with the
5956 merged constant. */
5967 }
5968 \f
5969 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5970 constant. */
5972 static tree
5975 {
5978 tree comp_const;
5979 tree minmax_const;
5981 tree inner;
5992 /* If something does not permit us to optimize, return the original tree. */
6000 /* Now handle all the various comparison codes. We only handle EQ_EXPR
6001 and GT_EXPR, doing the rest with recursive calls using logical
6002 simplifications. */
6004 {
6006 {
6007 tree tem
6014 }
6017 return
6019 optimize_minmax_comparison
6021 optimize_minmax_comparison
6026 /* MAX (X, 0) == 0 -> X <= 0 */
6030 /* MAX (X, 0) == 5 -> X == 5 */
6034 /* MAX (X, 0) == -1 -> false */
6038 /* MIN (X, 0) == 0 -> X >= 0 */
6042 /* MIN (X, 0) == 5 -> false */
6045 else
6046 /* MIN (X, 0) == -1 -> X == -1 */
6051 /* MAX (X, 0) > 0 -> X > 0
6052 MAX (X, 0) > 5 -> X > 5 */
6056 /* MAX (X, 0) > -1 -> true */
6060 /* MIN (X, 0) > 0 -> false
6061 MIN (X, 0) > 5 -> false */
6064 else
6065 /* MIN (X, 0) > -1 -> X > -1 */
6070 }
6071 }
6072 \f
6073 /* T is an integer expression that is being multiplied, divided, or taken a
6074 modulus (CODE says which and what kind of divide or modulus) by a
6075 constant C. See if we can eliminate that operation by folding it with
6076 other operations already in T. WIDE_TYPE, if non-null, is a type that
6077 should be used for the computation if wider than our type.
6079 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6080 (X * 2) + (Y * 4). We must, however, be assured that either the original
6081 expression would not overflow or that overflow is undefined for the type
6082 in the language in question.
6084 If we return a non-null expression, it is an equivalent form of the
6085 original computation, but need not be in the original type.
6087 We set *STRICT_OVERFLOW_P to true if the return values depends on
6088 signed overflow being undefined. Otherwise we do not change
6089 *STRICT_OVERFLOW_P. */
6091 static tree
6094 {
6095 /* To avoid exponential search depth, refuse to allow recursion past
6096 three levels. Beyond that (1) it's highly unlikely that we'll find
6097 something interesting and (2) we've probably processed it before
6098 when we built the inner expression. */
6101 tree ret;
6106 depth++;
6108 depth--;
6111 }
6113 static tree
6116 {
6127 /* Don't deal with constants of zero here; they confuse the code below. */
6137 /* Note that we need not handle conditional operations here since fold
6138 already handles those cases. So just do arithmetic here. */
6140 {
6142 /* For a constant, we can always simplify if we are a multiply
6143 or (for divide and modulus) if it is a multiple of our constant. */
6146 {
6149 /* If the multiplication overflowed, we lost information on it.
6150 See PR68142 and PR69845. */
6154 }
6158 /* If op0 is an expression ... */
6164 /* ... and has wrapping overflow, and its type is smaller
6165 than ctype, then we cannot pass through as widening. */
6170 /* ... or this is a truncation (t is narrower than op0),
6171 then we cannot pass through this narrowing. */
6174 /* ... or signedness changes for division or modulus,
6175 then we cannot pass through this conversion. */
6179 /* ... or has undefined overflow while the converted to
6180 type has not, we cannot do the operation in the inner type
6181 as that would introduce undefined overflow. */
6187 /* Pass the constant down and see if we can make a simplification. If
6188 we can, replace this expression with the inner simplification for
6189 possible later conversion to our or some other type. */
6194 code == MULT_EXPR
6196 strict_overflow_p))))
6201 /* If widening the type changes it from signed to unsigned, then we
6202 must avoid building ABS_EXPR itself as unsigned. */
6204 {
6208 {
6211 }
6213 }
6214 /* If the constant is negative, we cannot simplify this. */
6217 /* FALLTHROUGH */
6219 /* For division and modulus, type can't be unsigned, as e.g.
6220 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6221 For signed types, even with wrapping overflow, this is fine. */
6230 /* If widening the type changes the signedness, then we can't perform
6231 this optimization as that changes the result. */
6235 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6241 {
6248 }
6252 /* If the second operand is constant, this is a multiplication
6253 or floor division, by a power of two, so we can treat it that
6254 way unless the multiplier or divisor overflows. Signed
6255 left-shift overflow is implementation-defined rather than
6256 undefined in C90, so do not convert signed left shift into
6257 multiplication. */
6260 /* const_binop may not detect overflow correctly,
6261 so check for it explicitly here. */
6265 size_one_node,
6266 op1)))
6270 ctype,
6272 t1),
6277 /* See if we can eliminate the operation on both sides. If we can, we
6278 can return a new PLUS or MINUS. If we can't, the only remaining
6279 cases where we can do anything are if the second operand is a
6280 constant. */
6286 /* If not multiplication, we can only do this if both operands
6287 are divisible by c. */
6290 {
6295 }
6297 /* If this was a subtraction, negate OP1 and set it to be an addition.
6298 This simplifies the logic below. */
6300 {
6302 /* If OP1 was not easily negatable, the constant may be OP0. */
6304 {
6307 }
6308 }
6313 /* If either OP1 or C are negative, this optimization is not safe for
6314 some of the division and remainder types while for others we need
6315 to change the code. */
6317 {
6325 }
6327 /* If it's a multiply or a division/modulus operation of a multiple
6328 of our constant, do the operation and verify it doesn't overflow. */
6331 {
6334 /* We allow the constant to overflow with wrapping semantics. */
6338 }
6339 else
6342 /* If we have an unsigned type, we cannot widen the operation since it
6343 will change the result if the original computation overflowed. */
6347 /* If we were able to eliminate our operation from the first side,
6348 apply our operation to the second side and reform the PLUS. */
6352 /* The last case is if we are a multiply. In that case, we can
6353 apply the distributive law to commute the multiply and addition
6354 if the multiplication of the constants doesn't overflow
6355 and overflow is defined. With undefined overflow
6356 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6362 op1);
6367 /* We have a special case here if we are doing something like
6368 (C * 8) % 4 since we know that's zero. */
6371 /* If the multiplication can overflow we cannot optimize this. */
6375 {
6378 }
6380 /* ... fall through ... */
6384 /* If we can extract our operation from the LHS, do so and return a
6385 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6386 do something only if the second operand is a constant. */
6400 /* If these are the same operation types, we can associate them
6401 assuming no overflow. */
6403 {
6418 }
6420 /* If these operations "cancel" each other, we have the main
6421 optimizations of this pass, which occur when either constant is a
6422 multiple of the other, in which case we replace this with either an
6423 operation or CODE or TCODE.
6425 If we have an unsigned type, we cannot do this since it will change
6426 the result if the original computation overflowed. */
6433 {
6435 {
6442 }
6444 {
6451 }
6452 }
6457 }
6460 }
6461 \f
6462 /* Return a node which has the indicated constant VALUE (either 0 or
6463 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6464 and is of the indicated TYPE. */
6466 tree
6468 {
6477 else
6479 }
6482 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6483 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6484 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6485 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6486 COND is the first argument to CODE; otherwise (as in the example
6487 given here), it is the second argument. TYPE is the type of the
6488 original expression. Return NULL_TREE if no simplification is
6489 possible. */
6491 static tree
6496 {
6506 {
6510 /* If this operand throws an expression, then it does not make
6511 sense to try to perform a logical or arithmetic operation
6512 involving it. */
6517 }
6520 {
6525 }
6526 else
6527 /* Detect the case of mixing vector and scalar types - bail out. */
6533 /* This transformation is only worthwhile if we don't have to wrap ARG
6534 in a SAVE_EXPR and the operation can be simplified without recursing
6535 on at least one of the branches once its pushed inside the COND_EXPR. */
6544 {
6548 else
6550 }
6552 {
6556 else
6558 }
6560 /* Check that we have simplified at least one of the branches. */
6565 }
6567 \f
6568 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6570 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6571 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6572 ADDEND is the same as X.
6574 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6575 and finite. The problematic cases are when X is zero, and its mode
6576 has signed zeros. In the case of rounding towards -infinity,
6577 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6578 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6580 bool
6582 {
6586 /* Don't allow the fold with -fsignaling-nans. */
6590 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6594 /* In a vector or complex, we would need to check the sign of all zeros. */
6598 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6602 /* The mode has signed zeros, and we have to honor their sign.
6603 In this situation, there is only one case we can return true for.
6604 X - 0 is the same as X unless rounding towards -infinity is
6605 supported. */
6607 }
6609 /* Subroutine of fold() that optimizes comparisons of a division by
6610 a nonzero integer constant against an integer constant, i.e.
6611 X/C1 op C2.
6613 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6614 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6615 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6617 The function returns the constant folded tree if a simplification
6618 can be made, and NULL_TREE otherwise. */
6620 static tree
6623 {
6631 /* We have to do this the hard way to detect unsigned overflow.
6632 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6638 {
6643 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6647 }
6649 {
6653 {
6672 }
6673 }
6674 else
6675 {
6676 /* A negative divisor reverses the relational operators. */
6682 {
6701 }
6702 }
6705 {
6726 {
6729 }
6734 {
6737 }
6742 {
6745 }
6750 {
6753 }
6758 }
6761 }
6764 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6765 equality/inequality test, then return a simplified form of the test
6766 using a sign testing. Otherwise return NULL. TYPE is the desired
6767 result type. */
6769 static tree
6772 tree result_type)
6773 {
6774 /* If this is testing a single bit, we can optimize the test. */
6778 {
6779 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6780 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6784 /* This is only a win if casting to a signed type is cheap,
6785 i.e. when arg00's type is not a partial mode. */
6788 {
6791 result_type,
6794 }
6795 }
6798 }
6800 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6801 equality/inequality test, then return a simplified form of
6802 the test using shifts and logical operations. Otherwise return
6803 NULL. TYPE is the desired result type. */
6805 tree
6808 {
6809 /* If this is testing a single bit, we can optimize the test. */
6813 {
6822 /* First, see if we can fold the single bit test into a sign-bit
6823 test. */
6825 result_type);
6829 /* Otherwise we have (A & C) != 0 where C is a single bit,
6830 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6831 Similarly for (A & C) == 0. */
6833 /* If INNER is a right shift of a constant and it plus BITNUM does
6834 not overflow, adjust BITNUM and INNER. */
6840 {
6843 }
6845 /* If we are going to be able to omit the AND below, we must do our
6846 operations as unsigned. If we must use the AND, we have a choice.
6847 Normally unsigned is faster, but for some machines signed is. */
6865 /* Put the AND last so it can combine with more things. */
6868 /* Make sure to return the proper type. */
6872 }
6874 }
6876 /* Check whether we are allowed to reorder operands arg0 and arg1,
6877 such that the evaluation of arg1 occurs before arg0. */
6879 static bool
6881 {
6888 }
6890 /* Test whether it is preferable two swap two operands, ARG0 and
6891 ARG1, for example because ARG0 is an integer constant and ARG1
6892 isn't. If REORDER is true, only recommend swapping if we can
6893 evaluate the operands in reverse order. */
6895 bool
6897 {
6915 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6916 for commutative and comparison operators. Ensuring a canonical
6917 form allows the optimizers to find additional redundancies without
6918 having to explicitly check for both orderings. */
6924 /* Put SSA_NAMEs last. */
6930 /* Put variables last. */
6937 }
6940 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6941 means A >= Y && A != MAX, but in this case we know that
6942 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6944 static tree
6946 {
6953 else
6962 {
6965 }
6967 {
6970 }
6971 else
6978 {
6979 /* Convert the pointer types into integer before taking the difference. */
6983 }
6984 else
6991 }
6993 /* Fold a sum or difference of at least one multiplication.
6994 Returns the folded tree or NULL if no simplification could be made. */
6996 static tree
6999 {
7003 /* (A * C) +- (B * C) -> (A+-B) * C.
7004 (A * C) +- A -> A * (C+-1).
7005 We are most concerned about the case where C is a constant,
7006 but other combinations show up during loop reduction. Since
7007 it is not difficult, try all four possibilities. */
7010 {
7013 }
7015 {
7018 }
7019 else
7020 {
7021 /* We cannot generate constant 1 for fract. */
7026 }
7028 {
7031 }
7033 {
7035 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7036 the purpose of this canonicalization. */
7040 {
7043 }
7044 else
7046 }
7047 else
7048 {
7049 /* We cannot generate constant 1 for fract. */
7054 }
7066 /* No identical multiplicands; see if we can find a common
7067 power-of-two factor in non-power-of-two multiplies. This
7068 can help in multi-dimensional array access. */
7071 {
7074 tree maybe_same;
7078 /* Move min of absolute values to int11. */
7080 {
7085 }
7086 else
7090 /* The remainder should not be a constant, otherwise we
7091 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7092 increased the number of multiplications necessary. */
7094 {
7102 }
7103 }
7113 }
7115 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7116 specified by EXPR into the buffer PTR of length LEN bytes.
7117 Return the number of bytes placed in the buffer, or zero
7118 upon failure. */
7120 static int
7122 {
7136 {
7138 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7139 number of bytes. */
7143 {
7150 else
7152 }
7153 else
7158 }
7160 }
7163 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7164 specified by EXPR into the buffer PTR of length LEN bytes.
7165 Return the number of bytes placed in the buffer, or zero
7166 upon failure. */
7168 static int
7170 {
7174 FIXED_VALUE_TYPE value;
7190 }
7193 /* Subroutine of native_encode_expr. Encode the REAL_CST
7194 specified by EXPR into the buffer PTR of length LEN bytes.
7195 Return the number of bytes placed in the buffer, or zero
7196 upon failure. */
7198 static int
7200 {
7206 /* There are always 32 bits in each long, no matter the size of
7207 the hosts long. We handle floating point representations with
7208 up to 192 bits. */
7222 {
7227 {
7234 else
7236 }
7237 else
7243 }
7245 }
7247 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7248 specified by EXPR into the buffer PTR of length LEN bytes.
7249 Return the number of bytes placed in the buffer, or zero
7250 upon failure. */
7252 static int
7254 {
7256 tree part;
7271 }
7274 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7275 specified by EXPR into the buffer PTR of length LEN bytes.
7276 Return the number of bytes placed in the buffer, or zero
7277 upon failure. */
7279 static int
7281 {
7291 {
7293 {
7296 }
7307 }
7309 }
7312 /* Subroutine of native_encode_expr. Encode the STRING_CST
7313 specified by EXPR into the buffer PTR of length LEN bytes.
7314 Return the number of bytes placed in the buffer, or zero
7315 upon failure. */
7317 static int
7319 {
7321 HOST_WIDE_INT total_bytes;
7335 {
7338 {
7341 }
7344 }
7345 else
7348 }
7351 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7352 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7353 buffer PTR of length LEN bytes. If OFF is not -1 then start
7354 the encoding at byte offset OFF and encode at most LEN bytes.
7355 Return the number of bytes placed in the buffer, or zero upon failure. */
7357 int
7359 {
7360 /* We don't support starting at negative offset and -1 is special. */
7365 {
7386 }
7387 }
7390 /* Subroutine of native_interpret_expr. Interpret the contents of
7391 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7392 If the buffer cannot be interpreted, return NULL_TREE. */
7394 static tree
7396 {
7406 }
7409 /* Subroutine of native_interpret_expr. Interpret the contents of
7410 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7411 If the buffer cannot be interpreted, return NULL_TREE. */
7413 static tree
7415 {
7417 double_int result;
7418 FIXED_VALUE_TYPE fixed_value;
7428 }
7431 /* Subroutine of native_interpret_expr. Interpret the contents of
7432 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7433 If the buffer cannot be interpreted, return NULL_TREE. */
7435 static tree
7437 {
7441 /* There are always 32 bits in each long, no matter the size of
7442 the hosts long. We handle floating point representations with
7443 up to 192 bits. */
7444 REAL_VALUE_TYPE r;
7455 {
7456 /* Both OFFSET and BYTE index within a long;
7457 bitpos indexes the whole float. */
7460 {
7467 else
7469 }
7470 else
7471 {
7474 {
7475 /* Reverse bytes within each long, or within the entire float
7476 if it's smaller than a long (for HFmode). */
7479 }
7480 }
7484 }
7488 }
7491 /* Subroutine of native_interpret_expr. Interpret the contents of
7492 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7493 If the buffer cannot be interpreted, return NULL_TREE. */
7495 static tree
7497 {
7512 }
7515 /* Subroutine of native_interpret_expr. Interpret the contents of
7516 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7517 If the buffer cannot be interpreted, return NULL_TREE. */
7519 static tree
7521 {
7534 {
7539 }
7541 }
7544 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7545 the buffer PTR of length LEN as a constant of type TYPE. For
7546 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7547 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7548 return NULL_TREE. */
7550 tree
7552 {
7554 {
7576 }
7577 }
7579 /* Returns true if we can interpret the contents of a native encoding
7580 as TYPE. */
7582 static bool
7584 {
7586 {
7599 }
7600 }
7602 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7603 TYPE at compile-time. If we're unable to perform the conversion
7604 return NULL_TREE. */
7606 static tree
7608 {
7609 /* We support up to 512-bit values (for V8DFmode). */
7613 /* Check that the host and target are sane. */
7622 }
7624 /* Build an expression for the address of T. Folds away INDIRECT_REF
7625 to avoid confusing the gimplify process. */
7627 tree
7629 {
7630 /* The size of the object is not relevant when talking about its address. */
7635 {
7640 }
7650 {
7655 }
7656 else
7660 }
7662 /* Build an expression for the address of T. */
7664 tree
7666 {
7670 }
7672 /* Fold a unary expression of code CODE and type TYPE with operand
7673 OP0. Return the folded expression if folding is successful.
7674 Otherwise, return NULL_TREE. */
7676 tree
7678 {
7679 tree tem;
7680 tree arg0;
7688 {
7691 {
7692 /* Don't use STRIP_NOPS, because signedness of argument type
7693 matters. */
7695 }
7696 else
7697 {
7698 /* Strip any conversions that don't change the mode. This
7699 is safe for every expression, except for a comparison
7700 expression because its signedness is derived from its
7701 operands.
7703 Note that this is done as an internal manipulation within
7704 the constant folder, in order to find the simplest
7705 representation of the arguments so that their form can be
7706 studied. In any cases, the appropriate type conversions
7707 should be put back in the tree that will get out of the
7708 constant folder. */
7710 }
7713 {
7716 {
7720 }
7721 }
7722 }
7729 {
7736 {
7750 /* If this was a conversion, and all we did was to move into
7751 inside the COND_EXPR, bring it back out. But leave it if
7752 it is a conversion from integer to integer and the
7753 result precision is no wider than a word since such a
7754 conversion is cheap and may be optimized away by combine,
7755 while it couldn't if it were outside the COND_EXPR. Then return
7756 so we don't get into an infinite recursion loop taking the
7757 conversion out and then back in. */
7769 && (INTEGRAL_TYPE_P
7782 }
7783 }
7786 {
7792 CASE_CONVERT:
7796 {
7797 /* If we have (type) (a CMP b) and type is an integral type, return
7798 new expression involving the new type. Canonicalize
7799 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7800 non-integral type.
7801 Do not fold the result as that would not simplify further, also
7802 folding again results in recursions. */
7812 }
7814 /* Handle (T *)&A.B.C for A being of type T and B and C
7815 living at offset zero. This occurs frequently in
7816 C++ upcasting and then accessing the base. */
7820 {
7822 tree offset;
7823 machine_mode mode;
7825 tree base
7829 /* If the reference was to a (constant) zero offset, we can use
7830 the address of the base if it has the same base type
7831 as the result type and the pointer type is unqualified. */
7838 }
7842 /* Detect assigning a bitfield. */
7844 && DECL_BIT_FIELD
7846 {
7847 /* Don't leave an assignment inside a conversion
7848 unless assigning a bitfield. */
7850 /* First do the assignment, then return converted constant. */
7855 }
7857 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7858 constants (if x has signed type, the sign bit cannot be set
7859 in c). This folds extension into the BIT_AND_EXPR.
7860 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7861 very likely don't have maximal range for their precision and this
7862 transformation effectively doesn't preserve non-maximal ranges. */
7866 {
7877 <= HOST_BITS_PER_WIDE_INT
7879 {
7883 cst &= HOST_WIDE_INT_M1U
7887 && !flag_syntax_only
7890 {
7894 }
7895 }
7897 {
7902 }
7903 }
7905 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7906 cast (T1)X will fold away. We assume that this happens when X itself
7907 is a cast. */
7911 {
7915 return fold_build_pointer_plus_loc
7917 }
7919 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7920 of the same precision, and X is an integer type not narrower than
7921 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7927 {
7933 }
7935 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7936 type of X and Y (integer types only). */
7941 {
7942 /* Be careful not to introduce new overflows. */
7943 tree mult_type;
7946 else
7950 {
7957 }
7958 }
7964 {
7969 }
7980 /* Convert fabs((double)float) into (double)fabsf(float). */
7983 {
7989 targ0));
7990 }
7994 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8013 /* Note that the operand of this must be an int
8014 and its values must be 0 or 1.
8015 ("true" is a fixed value perhaps depending on the language,
8016 but we don't handle values other than 1 correctly yet.) */
8023 /* Fold *&X to X if X is an lvalue. */
8025 {
8032 }
8038 }
8041 /* If the operation was a conversion do _not_ mark a resulting constant
8042 with TREE_OVERFLOW if the original constant was not. These conversions
8043 have implementation defined behavior and retaining the TREE_OVERFLOW
8044 flag here would confuse later passes such as VRP. */
8045 tree
8048 {
8057 }
8059 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8060 operands OP0 and OP1. LOC is the location of the resulting expression.
8061 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8062 Return the folded expression if folding is successful. Otherwise,
8063 return NULL_TREE. */
8064 static tree
8067 {
8068 tree tem;
8070 /* We only do these simplifications if we are optimizing. */
8074 /* Check for things like (A || B) && (A || C). We can convert this
8075 to A || (B && C). Note that either operator can be any of the four
8076 truth and/or operations and the transformation will still be
8077 valid. Also note that we only care about order for the
8078 ANDIF and ORIF operators. If B contains side effects, this
8079 might change the truth-value of A. */
8086 {
8106 /* This case if tricky because we must either have commutative
8107 operators or else A10 must not have side-effects. */
8113 a01);
8114 }
8116 /* See if we can build a range comparison. */
8122 {
8126 }
8130 {
8134 }
8136 /* Check for the possibility of merging component references. If our
8137 lhs is another similar operation, try to merge its rhs with our
8138 rhs. Then try to merge our lhs and rhs. */
8152 {
8159 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8160 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8161 We don't want to pack more than two leafs to a non-IF AND/OR
8162 expression.
8163 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8164 equal to IF-CODE, then we don't want to add right-hand operand.
8165 If the inner right-hand side of left-hand operand has
8166 side-effects, or isn't simple, then we can't add to it,
8167 as otherwise we might destroy if-sequence. */
8170 /* Needed for sequence points to handle trappings, and
8171 side-effects. */
8173 {
8175 arg1);
8177 tem);
8178 }
8179 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8180 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8183 /* Needed for sequence points to handle trappings, and
8184 side-effects. */
8186 {
8191 }
8192 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8193 into (A OR B).
8194 For sequence point consistancy, we need to check for trapping,
8195 and side-effects. */
8199 }
8202 }
8204 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8205 by changing CODE to reduce the magnitude of constants involved in
8206 ARG0 of the comparison.
8207 Returns a canonicalized comparison tree if a simplification was
8208 possible, otherwise returns NULL_TREE.
8209 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8210 valid if signed overflow is undefined. */
8212 static tree
8216 {
8221 /* Match A +- CST code arg1. We can change this only if overflow
8222 is undefined. */
8225 /* In principle pointers also have undefined overflow behavior,
8226 but that causes problems elsewhere. */
8233 /* Identify the constant in arg0 and its sign. */
8237 /* Overflowed constants and zero will cause problems. */
8242 /* See if we can reduce the magnitude of the constant in
8243 arg0 by changing the comparison code. */
8244 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8248 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8252 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8256 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8260 else
8264 /* Now build the constant reduced in magnitude. But not if that
8265 would produce one outside of its types range. */
8281 }
8283 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8284 overflow further. Try to decrease the magnitude of constants involved
8285 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8286 and put sole constants at the second argument position.
8287 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8289 static tree
8292 {
8293 tree t;
8298 /* Try canonicalization by simplifying arg0. */
8303 {
8307 }
8309 /* Try canonicalization by simplifying arg1 using the swapped
8310 comparison. */
8318 }
8320 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8321 space. This is used to avoid issuing overflow warnings for
8322 expressions like &p->x which can not wrap. */
8324 static bool
8326 {
8333 wide_int wi_offset;
8339 else
8355 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8356 array. */
8358 {
8359 HOST_WIDE_INT base_size;
8364 }
8367 }
8369 /* Return a positive integer when the symbol DECL is known to have
8370 a nonzero address, zero when it's known not to (e.g., it's a weak
8371 symbol), and a negative integer when the symbol is not yet in the
8372 symbol table and so whether or not its address is zero is unknown. */
8373 static int
8375 {
8381 }
8383 /* Subroutine of fold_binary. This routine performs all of the
8384 transformations that are common to the equality/inequality
8385 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8386 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8387 fold_binary should call fold_binary. Fold a comparison with
8388 tree code CODE and type TYPE with operands OP0 and OP1. Return
8389 the folded comparison or NULL_TREE. */
8391 static tree
8394 {
8404 /* For comparisons of pointers we can decompose it to a compile time
8405 comparison of the base objects and the offsets into the object.
8406 This requires at least one operand being an ADDR_EXPR or a
8407 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8413 {
8416 machine_mode mode;
8420 /* Get base and offset for the access. Strip ADDR_EXPR for
8421 get_inner_reference, but put it back by stripping INDIRECT_REF
8422 off the base object if possible. indirect_baseN will be true
8423 if baseN is not an address but refers to the object itself. */
8426 {
8427 base0
8433 else
8435 }
8437 {
8441 {
8442 base0
8449 else
8451 }
8454 else
8458 {
8464 {
8467 }
8468 }
8469 }
8473 {
8474 base1
8480 else
8482 }
8484 {
8488 {
8489 base1
8496 else
8498 }
8501 else
8505 {
8511 {
8514 }
8515 }
8516 }
8518 /* If we have equivalent bases we might be able to simplify. */
8522 {
8523 /* We can fold this expression to a constant if the non-constant
8524 offset parts are equal. */
8533 {
8539 "occur when comparing P +- C1 with "
8541 WARN_STRICT_OVERFLOW_CONDITIONAL);
8544 {
8558 }
8559 }
8560 /* We can simplify the comparison to a comparison of the variable
8561 offset parts if the constant offset parts are equal.
8562 Be careful to use signed sizetype here because otherwise we
8563 mess with array offsets in the wrong way. This is possible
8564 because pointer arithmetic is restricted to retain within an
8565 object and overflow on pointer differences is undefined as of
8566 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8568 && (equality_code
8571 {
8572 /* By converting to signed sizetype we cover middle-end pointer
8573 arithmetic which operates on unsigned pointer types of size
8574 type size and ARRAY_REF offsets which are properly sign or
8575 zero extended from their type in case it is narrower than
8576 sizetype. */
8579 else
8583 else
8590 "occur when comparing P +- C1 with "
8592 WARN_STRICT_OVERFLOW_COMPARISON);
8595 }
8596 }
8597 /* For equal offsets we can simplify to a comparison of the
8598 base addresses. */
8600 && (indirect_base0
8602 && (indirect_base1
8607 {
8613 }
8614 /* Comparison between an ordinary (non-weak) symbol and a null
8615 pointer can be eliminated since such symbols must have a non
8616 null address. In C, relational expressions between pointers
8617 to objects and null pointers are undefined. The results
8618 below follow the C++ rules with the additional property that
8619 every object pointer compares greater than a null pointer.
8620 */
8623 /* Avoid folding references to struct members at offset 0 to
8624 prevent tests like '&ptr->firstmember == 0' from getting
8625 eliminated. When ptr is null, although the -> expression
8626 is strictly speaking invalid, GCC retains it as a matter
8627 of QoI. See PR c/44555. */
8629 /* The caller guarantees that when one of the arguments is
8630 constant (i.e., null in this case) it is second. */
8632 {
8634 {
8645 }
8646 }
8647 }
8649 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8650 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8651 the resulting offset is smaller in absolute value than the
8652 original one and has the same sign. */
8661 {
8666 tree cst;
8668 "occur when combining constants around "
8671 /* Put the constant on the side where it doesn't overflow and is
8672 of lower absolute value and of same sign than before. */
8679 {
8682 variable1,
8686 }
8694 {
8700 variable2);
8701 }
8702 }
8708 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8709 constant, we can simplify it. */
8714 {
8718 }
8720 /* If we are comparing an expression that just has comparisons
8721 of two integer values, arithmetic expressions of those comparisons,
8722 and constants, we can simplify it. There are only three cases
8723 to check: the two values can either be equal, the first can be
8724 greater, or the second can be greater. Fold the expression for
8725 those three values. Since each value must be 0 or 1, we have
8726 eight possibilities, each of which corresponds to the constant 0
8727 or 1 or one of the six possible comparisons.
8729 This handles common cases like (a > b) == 0 but also handles
8730 expressions like ((x > y) - (y > x)) > 0, which supposedly
8731 occur in macroized code. */
8734 {
8739 /* Don't handle degenerate cases here; they should already
8740 have been handled anyway. */
8749 {
8753 /* We can't just pass T to eval_subst in case cval1 or cval2
8754 was the same as ARG1. */
8756 tree high_result
8760 arg1);
8761 tree equal_result
8765 arg1);
8766 tree low_result
8770 arg1);
8772 /* All three of these results should be 0 or 1. Confirm they are.
8773 Then use those values to select the proper code to use. */
8778 {
8779 /* Make a 3-bit mask with the high-order bit being the
8780 value for `>', the next for '=', and the low for '<'. */
8784 {
8786 /* Always false. */
8807 /* Always true. */
8809 }
8812 {
8816 }
8818 }
8819 }
8820 }
8822 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8823 into a single range test. */
8831 {
8835 }
8838 }
8841 /* Subroutine of fold_binary. Optimize complex multiplications of the
8842 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8843 argument EXPR represents the expression "z" of type TYPE. */
8845 static tree
8847 {
8852 {
8855 }
8857 {
8860 }
8861 else
8862 {
8866 }
8875 }
8878 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8879 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8881 static bool
8883 {
8887 {
8890 }
8892 {
8898 else
8900 }
8901 else
8907 }
8909 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8910 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8911 NULL_TREE otherwise. */
8913 static tree
8915 {
8932 {
8936 }
8939 {
8945 }
8946 else
8948 }
8950 /* Try to fold a pointer difference of type TYPE two address expressions of
8951 array references AREF0 and AREF1 using location LOC. Return a
8952 simplified expression for the difference or NULL_TREE. */
8954 static tree
8957 {
8962 /* If the bases are array references as well, recurse. If the bases
8963 are pointer indirections compute the difference of the pointers.
8964 If the bases are equal, we are set. */
8967 && (base_offset
8971 && (base_offset
8977 {
8983 base_offset,
8986 }
8988 }
8990 /* If the real or vector real constant CST of type TYPE has an exact
8991 inverse, return it, else return NULL. */
8993 tree
8995 {
8996 REAL_VALUE_TYPE r;
8998 machine_mode mode;
9002 {
9018 {
9023 }
9029 }
9030 }
9032 /* Mask out the tz least significant bits of X of type TYPE where
9033 tz is the number of trailing zeroes in Y. */
9034 static wide_int
9036 {
9041 }
9043 /* Return true when T is an address and is known to be nonzero.
9044 For floating point we further ensure that T is not denormal.
9045 Similar logic is present in nonzero_address in rtlanal.h.
9047 If the return value is based on the assumption that signed overflow
9048 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9049 change *STRICT_OVERFLOW_P. */
9051 static bool
9053 {
9057 /* Doing something useful for floating point would need more work. */
9063 {
9066 strict_overflow_p);
9072 strict_overflow_p);
9080 }
9083 {
9086 strict_overflow_p);
9094 strict_overflow_p);
9109 strict_overflow_p);
9113 strict_overflow_p);
9116 {
9128 }
9132 }
9134 }
9136 /* Return true when T is an address and is known to be nonzero.
9137 Handle warnings about undefined signed overflow. */
9139 static bool
9141 {
9148 "determining that expression is always "
9150 WARN_STRICT_OVERFLOW_MISC);
9152 }
9154 /* Return true if T is known not to be equal to an integer W. */
9156 bool
9158 {
9160 value_range_type rtype;
9162 {
9171 {
9176 }
9181 /* If T has some known zero bits and W has any of those bits set,
9182 then T is known not to be equal to W. */
9190 }
9191 }
9193 /* Fold a binary expression of code CODE and type TYPE with operands
9194 OP0 and OP1. LOC is the location of the resulting expression.
9195 Return the folded expression if folding is successful. Otherwise,
9196 return NULL_TREE. */
9198 tree
9201 {
9216 /* Strip any conversions that don't change the mode. This is
9217 safe for every expression, except for a comparison expression
9218 because its signedness is derived from its operands. So, in
9219 the latter case, only strip conversions that don't change the
9220 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9221 preserved.
9223 Note that this is done as an internal manipulation within the
9224 constant folder, in order to find the simplest representation
9225 of the arguments so that their form can be studied. In any
9226 cases, the appropriate type conversions should be put back in
9227 the tree that will get out of the constant folder. */
9230 {
9233 }
9234 else
9235 {
9238 }
9240 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9241 constant but we can't do arithmetic on them. */
9243 {
9246 {
9250 }
9251 }
9253 /* If this is a commutative operation, and ARG0 is a constant, move it
9254 to ARG1 to reduce the number of tests below. */
9259 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9260 to ARG1 to reduce the number of tests below. */
9269 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9271 First check for cases where an arithmetic operation is applied to a
9272 compound, conditional, or comparison operation. Push the arithmetic
9273 operation inside the compound or conditional to see if any folding
9274 can then be done. Convert comparison to conditional for this purpose.
9275 The also optimizes non-constant cases that used to be done in
9276 expand_expr.
9278 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9279 one of the operands is a comparison and the other is a comparison, a
9280 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9281 code below would make the expression more complex. Change it to a
9282 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9283 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9296 {
9300 boolean_type_node,
9308 }
9312 {
9314 {
9319 tem);
9320 }
9323 {
9328 tem);
9329 }
9334 {
9340 }
9345 {
9351 }
9352 }
9355 {
9357 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9360 {
9366 }
9368 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9371 {
9372 tree base;
9373 HOST_WIDE_INT coffset;
9382 }
9387 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9393 arg1),
9395 arg0)));
9401 {
9402 /* X + (X / CST) * -CST is X % CST. */
9407 {
9416 cst0));
9417 }
9418 }
9420 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9421 one. Make sure the type is not saturating and has the signedness of
9422 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9423 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9430 {
9434 }
9437 {
9438 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9439 (plus (plus (mult) (mult)) (foo)) so that we can
9440 take advantage of the factoring cases below. */
9449 {
9455 else
9468 parg0),
9470 marg)),
9474 return
9480 parg1)));
9481 }
9482 }
9483 else
9484 {
9485 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9486 to __complex__ ( x, y ). This is not the same for SNaNs or
9487 if signed zeros are involved. */
9491 {
9498 {
9502 {
9508 }
9510 {
9516 }
9517 }
9518 }
9526 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9527 We associate floats only if the user has specified
9528 -fassociative-math. */
9532 {
9537 {
9538 tree tree0;
9541 }
9542 }
9543 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9544 We associate floats only if the user has specified
9545 -fassociative-math. */
9549 {
9554 {
9555 tree tree0;
9558 }
9559 }
9560 }
9562 bit_rotate:
9563 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9564 is a rotate of A by C1 bits. */
9565 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9566 is a rotate of A by B bits. */
9567 {
9569 tree rtype;
9578 /* Only create rotates in complete modes. Other cases are not
9579 expanded properly. */
9582 {
9596 {
9600 code0 == LSHIFT_EXPR
9604 }
9606 {
9614 element_precision
9618 return
9621 ? LROTATE_EXPR
9626 }
9628 {
9636 element_precision
9640 return fold_convert_loc
9643 ? LROTATE_EXPR
9647 }
9648 }
9649 }
9651 associate:
9652 /* In most languages, can't associate operations on floats through
9653 parentheses. Rather than remember where the parentheses were, we
9654 don't associate floats at all, unless the user has specified
9655 -fassociative-math.
9656 And, we need to make sure type is not saturating. */
9660 {
9666 /* Split both trees into variables, constants, and literals. Then
9667 associate each group together, the constants with literals,
9668 then the result with variables. This increases the chances of
9669 literals being recombined later and of generating relocatable
9670 expressions for the sum of a constant and literal. */
9676 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9680 /* With undefined overflow prefer doing association in a type
9681 which wraps on overflow, if that is one of the operand types. */
9684 {
9692 }
9694 /* With undefined overflow we can only associate constants with one
9695 variable, and constants whose association doesn't overflow. */
9698 {
9700 {
9706 {
9709 }
9716 {
9719 }
9725 /* The only case we can still associate with two variables
9726 is if they cancel out. */
9730 }
9731 }
9733 /* Only do something if we found more than two objects. Otherwise,
9734 nothing has changed and we risk infinite recursion. */
9740 {
9752 /* Preserve the MINUS_EXPR if the negative part of the literal is
9753 greater than the positive part. Otherwise, the multiplicative
9754 folding code (i.e extract_muldiv) may be fooled in case
9755 unsigned constants are subtracted, like in the following
9756 example: ((X*2 + 4) - 8U)/2. */
9758 {
9762 {
9766 }
9767 else
9768 {
9772 }
9773 }
9775 /* Don't introduce overflows through reassociation. */
9782 {
9784 return
9788 else
9789 {
9792 return
9796 }
9797 }
9800 return
9803 }
9804 }
9809 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9818 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9819 __complex__ ( x, -y ). This is not the same for SNaNs or if
9820 signed zeros are involved. */
9824 {
9831 {
9835 {
9837 arg1r ? arg1r
9842 }
9844 {
9848 arg1i ? arg1i
9851 }
9852 }
9853 }
9855 /* A - B -> A + (-B) if B is easily negatable. */
9859 /* Avoid this transformation if B is a positive REAL_CST. */
9867 /* Fold &a[i] - &a[j] to i-j. */
9872 {
9878 }
9881 && flag_unsafe_math_optimizations
9887 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9888 one. Make sure the type is not saturating and has the signedness of
9889 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9890 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9897 {
9901 }
9907 {
9908 /* Transform x * -C into -x * C if x is easily negatable. */
9922 {
9925 "occur when simplifying "
9927 WARN_STRICT_OVERFLOW_MISC);
9929 }
9931 /* Optimize z * conj(z) for integer complex numbers. */
9938 }
9939 else
9940 {
9941 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9942 This is not the same for NaNs or if signed zeros are
9943 involved. */
9949 {
9952 return
9958 return
9963 }
9965 /* Optimize z * conj(z) for floating point complex numbers.
9966 Guarded by flag_unsafe_math_optimizations as non-finite
9967 imaginary components don't produce scalar results. */
9976 }
9980 /* Canonicalize (X & C1) | C2. */
9984 {
9989 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9997 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10002 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10003 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10004 mode which allows further optimizations. */
10009 {
10013 {
10016 }
10017 }
10024 c3)),
10025 arg1);
10026 }
10028 /* See if this can be simplified into a rotate first. If that
10029 is unsuccessful continue in the association code. */
10033 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10041 /* See if this can be simplified into a rotate first. If that
10042 is unsuccessful continue in the association code. */
10046 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10051 {
10052 tree tem2;
10059 }
10060 /* Fold ~X & 1 as (X & 1) == 0. */
10064 {
10065 tree tem2;
10072 }
10073 /* Fold !X & 1 as X == 0. */
10076 {
10080 }
10082 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10083 multiple of 1 << CST. */
10085 {
10092 }
10094 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10095 bits from CST2. */
10099 {
10107 {
10108 /* Avoid the transform if arg1 is a mask of some
10109 mode which allows further optimizations. */
10116 }
10117 }
10119 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10120 ((A & N) + B) & M -> (A + B) & M
10121 Similarly if (N & M) == 0,
10122 ((A | N) + B) & M -> (A + B) & M
10123 and for - instead of + (or unary - instead of +)
10124 and/or ^ instead of |.
10125 If B is constant and (B & M) == 0, fold into A & M. */
10127 {
10136 {
10139 wide_int cst0;
10141 /* Now we know that arg0 is (C + D) or (C - D) or
10142 -C and arg1 (M) is == (1LL << cst) - 1.
10143 Store C into PMOP[0] and D into PMOP[1]. */
10147 {
10150 }
10157 {
10167 {
10170 }
10173 /* If C or D is of the form (A & N) where
10174 (N & M) == M, or of the form (A | N) or
10175 (A ^ N) where (N & M) == 0, replace it with A. */
10179 /* If C or D is a N where (N & M) == 0, it can be
10180 omitted (assumed 0). */
10188 }
10190 /* Only build anything new if we optimized one or both arguments
10191 above. */
10195 {
10198 {
10199 /* Perform the operations in a type that has defined
10200 overflow behavior. */
10206 }
10211 {
10219 else
10221 }
10224 else
10227 /* TEM is now the new binary +, - or unary - replacement. */
10231 }
10232 }
10233 }
10235 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10238 {
10243 return
10245 }
10250 /* Don't touch a floating-point divide by zero unless the mode
10251 of the constant can represent infinity. */
10257 /* (-A) / (-B) -> A / B */
10269 /* Fall through */
10272 /* Simplify A / (B << N) where A and B are positive and B is
10273 a power of 2, to A >> (N + log2(B)). */
10278 {
10281 {
10289 WARN_STRICT_OVERFLOW_MISC);
10295 }
10296 }
10298 /* Fall through */
10306 /* Convert -A / -B to A / B when the type is signed and overflow is
10307 undefined. */
10311 {
10314 "when distributing negation across "
10316 WARN_STRICT_OVERFLOW_MISC);
10321 }
10325 {
10328 "when distributing negation across "
10330 WARN_STRICT_OVERFLOW_MISC);
10335 }
10337 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10338 operation, EXACT_DIV_EXPR.
10340 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10341 At one time others generated faster code, it's not clear if they do
10342 after the last round to changes to the DIV code in expmed.c. */
10353 {
10357 WARN_STRICT_OVERFLOW_MISC);
10359 }
10371 {
10375 WARN_STRICT_OVERFLOW_MISC);
10377 }
10385 /* Since negative shift count is not well-defined,
10386 don't try to compute it in the compiler. */
10392 /* If we have a rotate of a bit operation with the rotate count and
10393 the second operand of the bit operation both constant,
10394 permute the two operations. */
10406 /* Two consecutive rotates adding up to the some integer
10407 multiple of the precision of the type can be ignored. */
10422 /* Note that the operands of this must be ints
10423 and their values must be 0 or 1.
10424 ("true" is a fixed value perhaps depending on the language.) */
10425 /* If first arg is constant zero, return it. */
10429 /* If either arg is constant true, drop it. */
10433 /* Preserve sequence points. */
10436 /* If second arg is constant zero, result is zero, but first arg
10437 must be evaluated. */
10440 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10441 case will be handled here. */
10445 /* !X && X is always false. */
10449 /* X && !X is always false. */
10454 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10455 means A >= Y && A != MAX, but in this case we know that
10456 A < X <= MAX. */
10460 {
10468 }
10477 /* Note that the operands of this must be ints
10478 and their values must be 0 or true.
10479 ("true" is a fixed value perhaps depending on the language.) */
10480 /* If first arg is constant true, return it. */
10484 /* If either arg is constant zero, drop it. */
10488 /* Preserve sequence points. */
10491 /* If second arg is constant true, result is true, but we must
10492 evaluate first arg. */
10495 /* Likewise for first arg, but note this only occurs here for
10496 TRUTH_OR_EXPR. */
10500 /* !X || X is always true. */
10504 /* X || !X is always true. */
10509 /* (X && !Y) || (!X && Y) is X ^ Y */
10512 {
10529 }
10538 /* If the second arg is constant zero, drop it. */
10541 /* If the second arg is constant true, this is a logical inversion. */
10543 {
10546 }
10547 /* Identical arguments cancel to zero. */
10551 /* !X ^ X is always true. */
10556 /* X ^ !X is always true. */
10572 /* bool_var != 1 becomes !bool_var. */
10579 /* bool_var == 0 becomes !bool_var. */
10586 /* !exp != 0 becomes !exp */
10591 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10600 {
10606 }
10608 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10617 {
10623 }
10625 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
10633 code == NE_EXPR
10637 /* Transform comparisons of the form X CMP C - X if C % 2 == 1. */
10645 code == NE_EXPR
10649 /* If this is an EQ or NE comparison with zero and ARG0 is
10650 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10651 two operations, but the latter can be done in one less insn
10652 on machines that have only two-operand insns or on which a
10653 constant cannot be the first operand. */
10656 {
10661 {
10668 arg1);
10669 }
10672 {
10679 arg1);
10680 }
10681 }
10683 /* If this is an NE or EQ comparison of zero against the result of a
10684 signed MOD operation whose second operand is a power of 2, make
10685 the MOD operation unsigned since it is simpler and equivalent. */
10693 {
10703 }
10705 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10706 C1 is a valid shift constant, and C2 is a power of two, i.e.
10707 a single bit. */
10711 == INTEGER_CST
10714 {
10719 /* Check for a valid shift count. */
10721 {
10725 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10726 can be rewritten as (X & (C2 << C1)) != 0. */
10728 {
10733 }
10734 /* Otherwise, for signed (arithmetic) shifts,
10735 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10736 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10740 /* Otherwise, of unsigned (logical) shifts,
10741 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10742 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10743 else
10747 arg000);
10748 }
10749 }
10751 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
10752 Similarly for NE_EXPR. */
10756 {
10760 tree dandnotc
10763 notc);
10767 }
10769 /* If this is a comparison of a field, we may be able to simplify it. */
10772 /* Handle the constant case even without -O
10773 to make sure the warnings are given. */
10775 {
10779 }
10781 /* Optimize comparisons of strlen vs zero to a compare of the
10782 first character of the string vs zero. To wit,
10783 strlen(ptr) == 0 => *ptr == 0
10784 strlen(ptr) != 0 => *ptr != 0
10785 Other cases should reduce to one of these two (or a constant)
10786 due to the return value of strlen being unsigned. */
10789 {
10797 {
10802 }
10803 }
10805 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10806 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10810 {
10815 {
10817 {
10820 }
10823 }
10824 }
10826 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10827 (X & C) == 0 when C is a single bit. */
10832 {
10839 arg1));
10840 }
10842 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10843 constant C is a power of two, i.e. a single bit. */
10850 {
10854 }
10856 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10857 when is C is a power of two, i.e. a single bit. */
10864 {
10870 }
10874 {
10877 }
10879 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10882 {
10895 arg01),
10904 arg01),
10913 arg00),
10922 arg00),
10924 }
10928 {
10935 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10936 operand_equal_p guarantees no side-effects so we don't need
10937 to use omit_one_operand on Z. */
10941 arg10));
10945 arg11));
10949 arg10));
10953 arg11));
10955 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10958 {
10964 }
10965 }
10967 /* Attempt to simplify equality/inequality comparisons of complex
10968 values. Only lower the comparison if the result is known or
10969 can be simplified to a single scalar comparison. */
10974 {
10979 {
10982 }
10983 else
10984 {
10987 }
10990 {
10993 }
10994 else
10995 {
10998 }
11002 {
11004 {
11009 }
11010 else
11011 {
11016 }
11017 }
11021 {
11023 {
11028 }
11029 else
11030 {
11035 }
11036 }
11037 }
11049 /* Transform comparisons of the form X +- C CMP X. */
11056 {
11063 else
11066 /* (X - c) > X becomes false. */
11070 {
11074 "occur when assuming that (X - c) > X "
11076 WARN_STRICT_OVERFLOW_ALL);
11078 }
11080 /* Likewise (X + c) < X becomes false. */
11084 {
11088 "occur when assuming that "
11090 WARN_STRICT_OVERFLOW_ALL);
11092 }
11094 /* Convert (X - c) <= X to true. */
11099 {
11103 "occur when assuming that "
11105 WARN_STRICT_OVERFLOW_ALL);
11107 }
11109 /* Convert (X + c) >= X to true. */
11114 {
11118 "occur when assuming that "
11120 WARN_STRICT_OVERFLOW_ALL);
11122 }
11125 {
11126 /* Convert X + c > X and X - c < X to true for integers. */
11130 {
11133 "not occur when assuming that "
11135 WARN_STRICT_OVERFLOW_ALL);
11137 }
11142 {
11145 "not occur when assuming that "
11147 WARN_STRICT_OVERFLOW_ALL);
11149 }
11151 /* Convert X + c <= X and X - c >= X to false for integers. */
11155 {
11158 "not occur when assuming that "
11160 WARN_STRICT_OVERFLOW_ALL);
11162 }
11167 {
11170 "not occur when assuming that "
11172 WARN_STRICT_OVERFLOW_ALL);
11174 }
11175 }
11176 }
11178 /* If we are comparing an ABS_EXPR with a constant, we can
11179 convert all the cases into explicit comparisons, but they may
11180 well not be faster than doing the ABS and one comparison.
11181 But ABS (X) <= C is a range comparison, which becomes a subtraction
11182 and a comparison, and is probably faster. */
11196 /* Convert ABS_EXPR<x> >= 0 to true. */
11203 {
11206 "when simplifying comparison of "
11208 WARN_STRICT_OVERFLOW_CONDITIONAL);
11211 arg0);
11212 }
11214 /* Convert ABS_EXPR<x> < 0 to false. */
11219 {
11222 "when simplifying comparison of "
11224 WARN_STRICT_OVERFLOW_CONDITIONAL);
11227 arg0);
11228 }
11230 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11231 and similarly for >= into !=. */
11241 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11242 otherwise Y might be >= # of bits in X's type and thus e.g.
11243 (unsigned char) (1 << Y) for Y 15 might be 0.
11244 If the cast is widening, then 1 << Y should have unsigned type,
11245 otherwise if Y is number of bits in the signed shift type minus 1,
11246 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11247 31 might be 0xffffffff80000000. */
11258 {
11264 }
11276 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11277 {
11289 }
11294 /* When pedantic, a compound expression can be neither an lvalue
11295 nor an integer constant expression. */
11298 /* Don't let (0, 0) be null pointer constant. */
11304 /* An ASSERT_EXPR should never be passed to fold_binary. */
11310 }
11312 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11313 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11314 of GOTO_EXPR. */
11316 static tree
11318 {
11320 {
11327 /* ... fall through ... */
11331 }
11332 }
11334 /* Return whether the sub-tree ST contains a label which is accessible from
11335 outside the sub-tree. */
11337 static bool
11339 {
11340 return
11342 }
11344 /* Fold a ternary expression of code CODE and type TYPE with operands
11345 OP0, OP1, and OP2. Return the folded expression if folding is
11346 successful. Otherwise, return NULL_TREE. */
11348 tree
11351 {
11352 tree tem;
11359 /* If this is a commutative operation, and OP0 is a constant, move it
11360 to OP1 to reduce the number of tests below. */
11369 /* Strip any conversions that don't change the mode. This is safe
11370 for every expression, except for a comparison expression because
11371 its signedness is derived from its operands. So, in the latter
11372 case, only strip conversions that don't change the signedness.
11374 Note that this is done as an internal manipulation within the
11375 constant folder, in order to find the simplest representation of
11376 the arguments so that their form can be studied. In any cases,
11377 the appropriate type conversions should be put back in the tree
11378 that will get out of the constant folder. */
11380 {
11383 }
11386 {
11389 }
11392 {
11395 }
11398 {
11402 {
11408 }
11413 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11414 so all simple results must be passed through pedantic_non_lvalue. */
11416 {
11419 /* Only optimize constant conditions when the selected branch
11420 has the same type as the COND_EXPR. This avoids optimizing
11421 away "c ? x : throw", where the throw has a void type.
11422 Avoid throwing away that operand which contains label. */
11429 }
11431 {
11436 {
11441 {
11449 }
11453 }
11454 }
11456 /* If we have A op B ? A : C, we may be able to convert this to a
11457 simpler expression, depending on the operation and the values
11458 of B and C. Signed zeros prevent all of these transformations,
11459 for reasons given above each one.
11461 Also try swapping the arguments and inverting the conditional. */
11466 {
11470 }
11474 op2,
11477 {
11481 {
11485 }
11486 }
11488 /* If the second operand is simpler than the third, swap them
11489 since that produces better jump optimization results. */
11492 {
11494 /* See if this can be inverted. If it can't, possibly because
11495 it was a floating-point inequality comparison, don't do
11496 anything. */
11500 }
11502 /* Convert A ? 1 : 0 to simply A. */
11507 /* If we try to convert OP0 to our type, the
11508 call to fold will try to move the conversion inside
11509 a COND, which will recurse. In that case, the COND_EXPR
11510 is probably the best choice, so leave it alone. */
11514 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11515 over COND_EXPR in cases such as floating point comparisons. */
11524 arg0)));
11526 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11531 {
11532 /* sign_bit_p looks through both zero and sign extensions,
11533 but for this optimization only sign extensions are
11534 usable. */
11537 {
11540 {
11543 }
11545 }
11546 /* sign_bit_p only checks ARG1 bits within A's precision.
11547 If <sign bit of A> has wider type than A, bits outside
11548 of A's precision in <sign bit of A> need to be checked.
11549 If they are all 0, this optimization needs to be done
11550 in unsigned A's type, if they are all 1 in signed A's type,
11551 otherwise this can't be done. */
11557 {
11559 tree tem_type;
11572 {
11575 }
11577 {
11580 }
11581 else
11583 }
11586 return
11592 arg1)));
11593 }
11595 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11596 already handled above. */
11601 {
11610 }
11612 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11613 is probably obsolete because the first operand should be a
11614 truth value (that's why we have the two cases above), but let's
11615 leave it in until we can confirm this for all front-ends. */
11627 /* Disable the transformations below for vectors, since
11628 fold_binary_op_with_conditional_arg may undo them immediately,
11629 yielding an infinite loop. */
11633 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11642 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11647 {
11649 /* Only perform transformation if ARG0 is easily inverted. */
11653 ? BIT_IOR_EXPR
11656 arg1);
11657 }
11659 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11664 {
11666 /* Only perform transformation if ARG0 is easily inverted. */
11672 op2);
11673 }
11675 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11687 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11688 of fold_ternary on them. */
11696 {
11706 {
11711 {
11719 }
11720 }
11721 }
11723 /* On constants we can use native encode/interpret to constant
11724 fold (nearly) all BIT_FIELD_REFs. */
11728 {
11731 /* Limit us to a reasonable amount of work. To relax the
11732 other limitations we need bit-shifting of the buffer
11733 and rounding up the size. */
11737 {
11739 unsigned HOST_WIDE_INT len
11744 {
11749 }
11750 }
11751 }
11756 /* For integers we can decompose the FMA if possible. */
11768 {
11784 {
11789 /* Make sure that the perm value is in an acceptable
11790 range. */
11799 else
11804 }
11807 {
11812 }
11817 {
11822 }
11828 {
11832 }
11837 /* Some targets are deficient and fail to expand a single
11838 argument permutation while still allowing an equivalent
11839 2-argument version. */
11843 {
11846 }
11849 {
11856 }
11860 }
11866 }
11868 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11869 of an array (or vector). */
11871 tree
11873 {
11878 {
11881 {
11882 /* Static constructors for variably sized objects makes no sense. */
11886 }
11887 }
11898 offset_int max_index;
11903 {
11904 /* Array constructor might explicitly set index, or specify a range,
11905 or leave index NULL meaning that it is next index after previous
11906 one. */
11908 {
11911 else
11912 {
11916 }
11917 }
11918 else
11919 {
11925 }
11927 /* Do we have match? */
11931 }
11933 }
11935 /* Perform constant folding and related simplification of EXPR.
11936 The related simplifications include x*1 => x, x*0 => 0, etc.,
11937 and application of the associative law.
11938 NOP_EXPR conversions may be removed freely (as long as we
11939 are careful not to change the type of the overall expression).
11940 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11941 but we can constant-fold them if they have constant operands. */
11943 #ifdef ENABLE_FOLD_CHECKING
11944 # define fold(x) fold_1 (x)
11946 static
11947 #endif
11948 tree
11950 {
11954 tree tem;
11957 /* Return right away if a constant. */
11961 /* CALL_EXPR-like objects with variable numbers of operands are
11962 treated specially. */
11964 {
11966 {
11969 }
11971 }
11974 {
11979 {
11997 }
11998 }
12001 {
12003 {
12010 {
12015 }
12018 }
12020 /* Return a VECTOR_CST if possible. */
12022 {
12028 tree val;
12034 }
12042 }
12044 #ifdef ENABLE_FOLD_CHECKING
12045 #undef fold
12052 /* When --enable-checking=fold, compute a digest of expr before
12053 and after actual fold call to see if fold did not accidentally
12054 change original expr. */
12056 tree
12058 {
12059 tree ret;
12079 }
12081 void
12083 {
12094 }
12096 static void
12098 {
12100 }
12102 static void
12105 {
12111 recursive_label:
12121 {
12122 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12127 }
12135 {
12136 /* Allow these fields to be modified. */
12137 tree tmp;
12146 {
12149 }
12150 }
12161 {
12164 {
12179 }
12183 {
12196 }
12213 {
12219 }
12222 {
12224 {
12227 }
12229 }
12240 {
12243 }
12253 }
12254 }
12256 /* Helper function for outputting the checksum of a tree T. When
12257 debugging with gdb, you can "define mynext" to be "next" followed
12258 by "call debug_fold_checksum (op0)", then just trace down till the
12259 outputs differ. */
12261 DEBUG_FUNCTION void
12263 {
12278 }
12280 #endif
12282 /* Fold a unary tree expression with code CODE of type TYPE with an
12283 operand OP0. LOC is the location of the resulting expression.
12284 Return a folded expression if successful. Otherwise, return a tree
12285 expression with code CODE of type TYPE with an operand OP0. */
12287 tree
12290 {
12291 tree tem;
12292 #ifdef ENABLE_FOLD_CHECKING
12301 #endif
12307 #ifdef ENABLE_FOLD_CHECKING
12314 #endif
12316 }
12318 /* Fold a binary tree expression with code CODE of type TYPE with
12319 operands OP0 and OP1. LOC is the location of the resulting
12320 expression. Return a folded expression if successful. Otherwise,
12321 return a tree expression with code CODE of type TYPE with operands
12322 OP0 and OP1. */
12324 tree
12327 MEM_STAT_DECL)
12328 {
12329 tree tem;
12330 #ifdef ENABLE_FOLD_CHECKING
12347 #endif
12353 #ifdef ENABLE_FOLD_CHECKING
12368 #endif
12370 }
12372 /* Fold a ternary tree expression with code CODE of type TYPE with
12373 operands OP0, OP1, and OP2. Return a folded expression if
12374 successful. Otherwise, return a tree expression with code CODE of
12375 type TYPE with operands OP0, OP1, and OP2. */
12377 tree
12380 {
12381 tree tem;
12382 #ifdef ENABLE_FOLD_CHECKING
12406 #endif
12413 #ifdef ENABLE_FOLD_CHECKING
12436 #endif
12438 }
12440 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12441 arguments in ARGARRAY, and a null static chain.
12442 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12443 of type TYPE from the given operands as constructed by build_call_array. */
12445 tree
12448 {
12449 tree tem;
12450 #ifdef ENABLE_FOLD_CHECKING
12469 #endif
12475 #ifdef ENABLE_FOLD_CHECKING
12491 #endif
12493 }
12495 /* Perform constant folding and related simplification of initializer
12496 expression EXPR. These behave identically to "fold_buildN" but ignore
12497 potential run-time traps and exceptions that fold must preserve. */
12499 #define START_FOLD_INIT \
12500 int saved_signaling_nans = flag_signaling_nans;\
12501 int saved_trapping_math = flag_trapping_math;\
12502 int saved_rounding_math = flag_rounding_math;\
12503 int saved_trapv = flag_trapv;\
12504 int saved_folding_initializer = folding_initializer;\
12505 flag_signaling_nans = 0;\
12506 flag_trapping_math = 0;\
12507 flag_rounding_math = 0;\
12508 flag_trapv = 0;\
12509 folding_initializer = 1;
12511 #define END_FOLD_INIT \
12512 flag_signaling_nans = saved_signaling_nans;\
12513 flag_trapping_math = saved_trapping_math;\
12514 flag_rounding_math = saved_rounding_math;\
12515 flag_trapv = saved_trapv;\
12516 folding_initializer = saved_folding_initializer;
12518 tree
12521 {
12522 tree result;
12523 START_FOLD_INIT;
12527 END_FOLD_INIT;
12529 }
12531 tree
12534 {
12535 tree result;
12536 START_FOLD_INIT;
12540 END_FOLD_INIT;
12542 }
12544 tree
12547 {
12548 tree result;
12549 START_FOLD_INIT;
12553 END_FOLD_INIT;
12555 }
12557 #undef START_FOLD_INIT
12558 #undef END_FOLD_INIT
12560 /* Determine if first argument is a multiple of second argument. Return 0 if
12561 it is not, or we cannot easily determined it to be.
12563 An example of the sort of thing we care about (at this point; this routine
12564 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12565 fold cases do now) is discovering that
12567 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12569 is a multiple of
12571 SAVE_EXPR (J * 8)
12573 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12575 This code also handles discovering that
12577 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12579 is a multiple of 8 so we don't have to worry about dealing with a
12580 possible remainder.
12582 Note that we *look* inside a SAVE_EXPR only to determine how it was
12583 calculated; it is not safe for fold to do much of anything else with the
12584 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12585 at run time. For example, the latter example above *cannot* be implemented
12586 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12587 evaluation time of the original SAVE_EXPR is not necessarily the same at
12588 the time the new expression is evaluated. The only optimization of this
12589 sort that would be valid is changing
12591 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12593 divided by 8 to
12595 SAVE_EXPR (I) * SAVE_EXPR (J)
12597 (where the same SAVE_EXPR (J) is used in the original and the
12598 transformed version). */
12600 int
12602 {
12610 {
12612 /* Bitwise and provides a power of two multiple. If the mask is
12613 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12616 /* FALLTHRU */
12629 {
12633 /* const_binop may not detect overflow correctly,
12634 so check for it explicitly here. */
12638 size_one_node,
12639 op1)))
12642 }
12646 /* Can't handle conversions from non-integral or wider integral type. */
12652 /* .. fall through ... */
12669 SIGNED);
12673 }
12674 }
12676 #define tree_expr_nonnegative_warnv_p(X, Y) \
12679 #define RECURSE(X) \
12680 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12682 /* Return true if CODE or TYPE is known to be non-negative. */
12684 static bool
12686 {
12689 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12690 have a signed:1 type (where the value is -1 and 0). */
12693 }
12695 /* Return true if (CODE OP0) is known to be non-negative. If the return
12696 value is based on the assumption that signed overflow is undefined,
12697 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12698 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12700 bool
12703 {
12708 {
12710 /* We can't return 1 if flag_wrapv is set because
12711 ABS_EXPR<INT_MIN> = INT_MIN. */
12715 {
12718 }
12726 CASE_CONVERT:
12727 {
12732 {
12736 {
12740 }
12741 }
12743 {
12749 }
12750 }
12755 }
12757 /* We don't know sign of `t', so be conservative and return false. */
12759 }
12761 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12762 value is based on the assumption that signed overflow is undefined,
12763 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12764 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12766 bool
12770 {
12775 {
12781 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12782 both unsigned and at least 2 bits shorter than the result. */
12786 {
12791 {
12795 }
12796 }
12801 {
12802 /* x * x is always non-negative for floating point x
12803 or without overflow. */
12806 {
12811 }
12812 }
12814 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12815 both unsigned and their total bits is shorter than the result. */
12819 {
12838 {
12848 }
12849 }
12876 }
12878 /* We don't know sign of `t', so be conservative and return false. */
12880 }
12882 /* Return true if T is known to be non-negative. If the return
12883 value is based on the assumption that signed overflow is undefined,
12884 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12885 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12887 bool
12889 {
12894 {
12908 /* Limit the depth of recursion to avoid quadratic behavior.
12909 This is expected to catch almost all occurrences in practice.
12910 If this code misses important cases that unbounded recursion
12911 would not, passes that need this information could be revised
12912 to provide it through dataflow propagation. */
12920 }
12921 }
12923 /* Return true if T is known to be non-negative. If the return
12924 value is based on the assumption that signed overflow is undefined,
12925 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12926 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12928 bool
12931 {
12933 {
12934 CASE_CFN_ACOS:
12935 CASE_CFN_ACOSH:
12936 CASE_CFN_CABS:
12937 CASE_CFN_COSH:
12938 CASE_CFN_ERFC:
12939 CASE_CFN_EXP:
12940 CASE_CFN_EXP10:
12941 CASE_CFN_EXP2:
12942 CASE_CFN_FABS:
12943 CASE_CFN_FDIM:
12944 CASE_CFN_HYPOT:
12945 CASE_CFN_POW10:
12946 CASE_CFN_FFS:
12947 CASE_CFN_PARITY:
12948 CASE_CFN_POPCOUNT:
12949 CASE_CFN_CLZ:
12950 CASE_CFN_CLRSB:
12953 /* Always true. */
12956 CASE_CFN_SQRT:
12957 /* sqrt(-0.0) is -0.0. */
12962 CASE_CFN_ASINH:
12963 CASE_CFN_ATAN:
12964 CASE_CFN_ATANH:
12965 CASE_CFN_CBRT:
12966 CASE_CFN_CEIL:
12967 CASE_CFN_ERF:
12968 CASE_CFN_EXPM1:
12969 CASE_CFN_FLOOR:
12970 CASE_CFN_FMOD:
12971 CASE_CFN_FREXP:
12972 CASE_CFN_ICEIL:
12973 CASE_CFN_IFLOOR:
12974 CASE_CFN_IRINT:
12975 CASE_CFN_IROUND:
12976 CASE_CFN_LCEIL:
12977 CASE_CFN_LDEXP:
12978 CASE_CFN_LFLOOR:
12979 CASE_CFN_LLCEIL:
12980 CASE_CFN_LLFLOOR:
12981 CASE_CFN_LLRINT:
12982 CASE_CFN_LLROUND:
12983 CASE_CFN_LRINT:
12984 CASE_CFN_LROUND:
12985 CASE_CFN_MODF:
12986 CASE_CFN_NEARBYINT:
12987 CASE_CFN_RINT:
12988 CASE_CFN_ROUND:
12989 CASE_CFN_SCALB:
12990 CASE_CFN_SCALBLN:
12991 CASE_CFN_SCALBN:
12992 CASE_CFN_SIGNBIT:
12993 CASE_CFN_SIGNIFICAND:
12994 CASE_CFN_SINH:
12995 CASE_CFN_TANH:
12996 CASE_CFN_TRUNC:
12997 /* True if the 1st argument is nonnegative. */
13000 CASE_CFN_FMAX:
13001 /* True if the 1st OR 2nd arguments are nonnegative. */
13004 CASE_CFN_FMIN:
13005 /* True if the 1st AND 2nd arguments are nonnegative. */
13008 CASE_CFN_COPYSIGN:
13009 /* True if the 2nd argument is nonnegative. */
13012 CASE_CFN_POWI:
13013 /* True if the 1st argument is nonnegative or the second
13014 argument is an even integer. */
13020 CASE_CFN_POW:
13021 /* True if the 1st argument is nonnegative or the second
13022 argument is an even integer valued real. */
13024 {
13025 REAL_VALUE_TYPE c;
13026 HOST_WIDE_INT n;
13031 {
13032 REAL_VALUE_TYPE cint;
13036 }
13037 }
13042 }
13044 }
13046 /* Return true if T is known to be non-negative. If the return
13047 value is based on the assumption that signed overflow is undefined,
13048 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13049 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13051 static bool
13053 {
13059 {
13061 {
13065 /* If the initializer is non-void, then it's a normal expression
13066 that will be assigned to the slot. */
13070 /* Otherwise, the initializer sets the slot in some way. One common
13071 way is an assignment statement at the end of the initializer. */
13073 {
13081 else
13083 }
13089 }
13092 {
13098 arg0,
13099 arg1,
13101 }
13114 }
13115 }
13117 #undef RECURSE
13118 #undef tree_expr_nonnegative_warnv_p
13120 /* Return true if T is known to be non-negative. If the return
13121 value is based on the assumption that signed overflow is undefined,
13122 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13123 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13125 bool
13127 {
13134 {
13156 }
13159 {
13185 }
13186 }
13188 /* Return true if `t' is known to be non-negative. Handle warnings
13189 about undefined signed overflow. */
13191 bool
13193 {
13200 "determining that expression is always "
13202 WARN_STRICT_OVERFLOW_MISC);
13204 }
13207 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13208 For floating point we further ensure that T is not denormal.
13209 Similar logic is present in nonzero_address in rtlanal.h.
13211 If the return value is based on the assumption that signed overflow
13212 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13213 change *STRICT_OVERFLOW_P. */
13215 bool
13218 {
13220 {
13223 strict_overflow_p);
13226 {
13232 strict_overflow_p));
13233 }
13238 strict_overflow_p);
13242 }
13245 }
13247 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13248 For floating point we further ensure that T is not denormal.
13249 Similar logic is present in nonzero_address in rtlanal.h.
13251 If the return value is based on the assumption that signed overflow
13252 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13253 change *STRICT_OVERFLOW_P. */
13255 bool
13257 tree type,
13258 tree op0,
13260 {
13263 {
13267 {
13268 /* With the presence of negative values it is hard
13269 to say something. */
13276 /* One of operands must be positive and the other non-negative. */
13277 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13278 overflows, on a twos-complement machine the sum of two
13279 nonnegative numbers can never be zero. */
13281 strict_overflow_p)
13283 strict_overflow_p));
13284 }
13289 {
13291 strict_overflow_p)
13293 strict_overflow_p))
13294 {
13297 }
13298 }
13307 {
13310 }
13317 {
13321 /* When both operands are nonzero, then MAX must be too. */
13323 strict_overflow_p))
13326 /* MAX where operand 0 is positive is positive. */
13328 strict_overflow_p);
13329 }
13330 /* MAX where operand 1 is positive is positive. */
13335 {
13339 }
13344 strict_overflow_p)
13346 strict_overflow_p));
13350 }
13353 }
13355 /* Return true when T is an address and is known to be nonzero.
13356 For floating point we further ensure that T is not denormal.
13357 Similar logic is present in nonzero_address in rtlanal.h.
13359 If the return value is based on the assumption that signed overflow
13360 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13361 change *STRICT_OVERFLOW_P. */
13363 bool
13365 {
13368 {
13373 {
13385 /* For objects in symbol table check if we know they are non-zero.
13386 Don't do anything for variables and functions before symtab is built;
13387 it is quite possible that they will be declared weak later. */
13392 /* Function local objects are never NULL. */
13399 /* Constants are never weak. */
13404 }
13412 {
13416 }
13421 }
13423 }
13425 #define integer_valued_real_p(X) \
13428 #define RECURSE(X) \
13429 ((integer_valued_real_p) (X, depth + 1))
13431 /* Return true if the floating point result of (CODE OP0) has an
13432 integer value. We also allow +Inf, -Inf and NaN to be considered
13433 integer values. Return false for signaling NaN.
13435 DEPTH is the current nesting depth of the query. */
13437 bool
13439 {
13441 {
13448 CASE_CONVERT:
13449 {
13456 }
13460 }
13462 }
13464 /* Return true if the floating point result of (CODE OP0 OP1) has an
13465 integer value. We also allow +Inf, -Inf and NaN to be considered
13466 integer values. Return false for signaling NaN.
13468 DEPTH is the current nesting depth of the query. */
13470 bool
13472 {
13474 {
13484 }
13486 }
13488 /* Return true if the floating point result of calling FNDECL with arguments
13489 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13490 considered integer values. Return false for signaling NaN. If FNDECL
13491 takes fewer than 2 arguments, the remaining ARGn are null.
13493 DEPTH is the current nesting depth of the query. */
13495 bool
13497 {
13499 {
13500 CASE_CFN_CEIL:
13501 CASE_CFN_FLOOR:
13502 CASE_CFN_NEARBYINT:
13503 CASE_CFN_RINT:
13504 CASE_CFN_ROUND:
13505 CASE_CFN_TRUNC:
13508 CASE_CFN_FMIN:
13509 CASE_CFN_FMAX:
13514 }
13516 }
13518 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13519 has an integer value. We also allow +Inf, -Inf and NaN to be
13520 considered integer values. Return false for signaling NaN.
13522 DEPTH is the current nesting depth of the query. */
13524 bool
13526 {
13528 {
13536 /* Limit the depth of recursion to avoid quadratic behavior.
13537 This is expected to catch almost all occurrences in practice.
13538 If this code misses important cases that unbounded recursion
13539 would not, passes that need this information could be revised
13540 to provide it through dataflow propagation. */
13544 depth));
13548 }
13550 }
13552 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13553 has an integer value. We also allow +Inf, -Inf and NaN to be
13554 considered integer values. Return false for signaling NaN.
13556 DEPTH is the current nesting depth of the query. */
13558 static bool
13560 {
13562 {
13573 }
13575 }
13577 #undef RECURSE
13578 #undef integer_valued_real_p
13580 /* Return true if the floating point expression T has an integer value.
13581 We also allow +Inf, -Inf and NaN to be considered integer values.
13582 Return false for signaling NaN.
13584 DEPTH is the current nesting depth of the query. */
13586 bool
13588 {
13594 {
13610 }
13613 {
13619 {
13628 }
13632 }
13633 }
13635 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13636 attempt to fold the expression to a constant without modifying TYPE,
13637 OP0 or OP1.
13639 If the expression could be simplified to a constant, then return
13640 the constant. If the expression would not be simplified to a
13641 constant, then return NULL_TREE. */
13643 tree
13645 {
13648 }
13650 /* Given the components of a unary expression CODE, TYPE and OP0,
13651 attempt to fold the expression to a constant without modifying
13652 TYPE or OP0.
13654 If the expression could be simplified to a constant, then return
13655 the constant. If the expression would not be simplified to a
13656 constant, then return NULL_TREE. */
13658 tree
13660 {
13663 }
13665 /* If EXP represents referencing an element in a constant string
13666 (either via pointer arithmetic or array indexing), return the
13667 tree representing the value accessed, otherwise return NULL. */
13669 tree
13671 {
13675 {
13677 tree index;
13678 tree string;
13683 else
13684 {
13688 /* Optimize the special-case of a zero lower bound.
13690 We convert the low_bound to sizetype to avoid some problems
13691 with constant folding. (E.g. suppose the lower bound is 1,
13692 and its mode is QI. Without the conversion,l (ARRAY
13693 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13694 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13700 }
13713 }
13715 }
13717 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13718 an integer constant, real, or fixed-point constant.
13720 TYPE is the type of the result. */
13722 static tree
13724 {
13728 {
13730 {
13737 }
13744 {
13745 FIXED_VALUE_TYPE f;
13750 /* Propagate overflow flags. */
13754 }
13758 }
13761 }
13763 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13764 an integer constant or real constant.
13766 TYPE is the type of the result. */
13768 tree
13770 {
13774 {
13776 {
13777 /* If the value is unsigned or non-negative, then the absolute value
13778 is the same as the ordinary value. */
13782 /* If the value is negative, then the absolute value is
13783 its negation. */
13784 else
13785 {
13790 }
13791 }
13797 else
13803 }
13806 }
13808 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13809 constant. TYPE is the type of the result. */
13811 static tree
13813 {
13817 }
13819 /* Given CODE, a relational operator, the target type, TYPE and two
13820 constant operands OP0 and OP1, return the result of the
13821 relational operation. If the result is not a compile time
13822 constant, then return NULL_TREE. */
13824 static tree
13826 {
13829 /* From here on, the only cases we handle are when the result is
13830 known to be a constant. */
13833 {
13837 /* Handle the cases where either operand is a NaN. */
13839 {
13841 {
13869 }
13872 }
13875 }
13878 {
13882 }
13884 /* Handle equality/inequality of complex constants. */
13886 {
13897 else
13899 }
13902 {
13904 {
13905 /* Have vector comparison with scalar boolean result. */
13910 {
13915 }
13919 }
13926 {
13938 }
13941 }
13943 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13945 To compute GT, swap the arguments and do LT.
13946 To compute GE, do LT and invert the result.
13947 To compute LE, swap the arguments, do LT and invert the result.
13948 To compute NE, do EQ and invert the result.
13950 Therefore, the code below must handle only EQ and LT. */
13953 {
13956 }
13958 /* Note that it is safe to invert for real values here because we
13959 have already handled the one case that it matters. */
13963 {
13966 }
13968 /* Compute a result for LT or EQ if args permit;
13969 Otherwise return T. */
13971 {
13974 else
13976 }
13977 else
13983 }
13985 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13986 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13987 itself. */
13989 tree
13991 {
13992 /* If the expression does not have side effects then we don't have to wrap
13993 it with a cleanup point expression. */
13997 /* If the expression is a return, check to see if the expression inside the
13998 return has no side effects or the right hand side of the modify expression
13999 inside the return. If either don't have side effects set we don't need to
14000 wrap the expression in a cleanup point expression. Note we don't check the
14001 left hand side of the modify because it should always be a return decl. */
14003 {
14010 }
14013 }
14015 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14016 of an indirection through OP0, or NULL_TREE if no simplification is
14017 possible. */
14019 tree
14021 {
14023 tree subtype;
14031 {
14034 /* *&CONST_DECL -> to the value of the const decl. */
14037 /* *&p => p; make sure to handle *&"str"[cst] here. */
14039 {
14043 else
14045 }
14046 /* *(foo *)&fooarray => fooarray[0] */
14049 && (!in_gimple_form
14051 {
14061 }
14062 /* *(foo *)&complexfoo => __real__ complexfoo */
14066 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14069 {
14073 }
14074 }
14078 {
14084 {
14085 tree op00type;
14089 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14092 {
14094 unsigned HOST_WIDE_INT max_offset
14099 {
14106 }
14107 }
14108 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14111 {
14115 }
14116 /* ((foo *)&fooarray)[1] => fooarray[1] */
14119 {
14129 }
14130 }
14131 }
14133 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14136 && (!in_gimple_form
14138 {
14139 tree type_domain;
14149 NULL_TREE);
14150 }
14153 }
14155 /* Builds an expression for an indirection through T, simplifying some
14156 cases. */
14158 tree
14160 {
14168 }
14170 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14172 tree
14174 {
14179 else
14181 }
14183 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14184 whose result is ignored. The type of the returned tree need not be
14185 the same as the original expression. */
14187 tree
14189 {
14195 {
14206 else
14212 {
14228 }
14233 }
14234 }
14236 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14238 tree
14240 {
14246 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14247 have to do anything. Only do this when we are not given a const,
14248 because in that case, this check is more expensive than just
14249 doing it. */
14251 {
14256 }
14258 /* If divisor is a power of two, simplify this to bit manipulation. */
14260 {
14262 {
14276 }
14277 else
14278 {
14279 tree t;
14285 }
14286 }
14287 else
14288 {
14293 }
14296 }
14298 /* Likewise, but round down. */
14300 tree
14302 {
14309 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14310 have to do anything. Only do this when we are not given a const,
14311 because in that case, this check is more expensive than just
14312 doing it. */
14314 {
14319 }
14321 /* If divisor is a power of two, simplify this to bit manipulation. */
14323 {
14324 tree t;
14328 }
14329 else
14330 {
14335 }
14338 }
14340 /* Returns the pointer to the base of the object addressed by EXP and
14341 extracts the information about the offset of the access, storing it
14342 to PBITPOS and POFFSET. */
14344 static tree
14347 {
14348 tree core;
14349 machine_mode mode;
14351 HOST_WIDE_INT bitsize;
14355 {
14360 }
14361 else
14362 {
14366 }
14369 }
14371 /* Returns true if addresses of E1 and E2 differ by a constant, false
14372 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14374 bool
14376 {
14390 {
14400 }
14402 {
14403 /* If only one of the offsets is non-constant, the difference cannot
14404 be a constant. */
14406 }
14407 else
14412 }
14414 /* Return OFF converted to a pointer offset type suitable as offset for
14415 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14416 tree
14418 {
14420 }
14422 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14423 tree
14425 {
14428 }
14430 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14431 tree
14433 {
14436 }
14438 /* Return a char pointer for a C string if it is a string constant
14439 or sum of string constant and integer constant. */
14443 {
14444 tree offset_node;
14457 }