| blob | c5d9a79ed28c8d346645eb2f4ca5d482a7f7e1d7 |
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. */
81 #ifndef LOAD_EXTEND_OP
82 #define LOAD_EXTEND_OP(M) UNKNOWN
83 #endif
85 /* Nonzero if we are folding constants inside an initializer; zero
86 otherwise. */
89 /* The following constants represent a bit based encoding of GCC's
90 comparison operators. This encoding simplifies transformations
91 on relational comparison operators, such as AND and OR. */
109 };
147 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
148 Otherwise, return LOC. */
150 static location_t
152 {
155 }
157 /* Similar to protected_set_expr_location, but never modify x in place,
158 if location can and needs to be set, unshare it. */
162 {
168 {
171 }
173 }
174 \f
175 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
176 division and returns the quotient. Otherwise returns
177 NULL_TREE. */
179 tree
181 {
182 widest_int quo;
189 }
190 \f
191 /* This is nonzero if we should defer warnings about undefined
192 overflow. This facility exists because these warnings are a
193 special case. The code to estimate loop iterations does not want
194 to issue any warnings, since it works with expressions which do not
195 occur in user code. Various bits of cleanup code call fold(), but
196 only use the result if it has certain characteristics (e.g., is a
197 constant); that code only wants to issue a warning if the result is
198 used. */
202 /* If a warning about undefined overflow is deferred, this is the
203 warning. Note that this may cause us to turn two warnings into
204 one, but that is fine since it is sufficient to only give one
205 warning per expression. */
209 /* If a warning about undefined overflow is deferred, this is the
210 level at which the warning should be emitted. */
214 /* Start deferring overflow warnings. We could use a stack here to
215 permit nested calls, but at present it is not necessary. */
217 void
219 {
221 }
223 /* Stop deferring overflow warnings. If there is a pending warning,
224 and ISSUE is true, then issue the warning if appropriate. STMT is
225 the statement with which the warning should be associated (used for
226 location information); STMT may be NULL. CODE is the level of the
227 warning--a warn_strict_overflow_code value. This function will use
228 the smaller of CODE and the deferred code when deciding whether to
229 issue the warning. CODE may be zero to mean to always use the
230 deferred code. */
232 void
234 {
236 location_t locus;
241 {
247 }
258 /* Use the smallest code level when deciding to issue the
259 warning. */
268 else
271 }
273 /* Stop deferring overflow warnings, ignoring any deferred
274 warnings. */
276 void
278 {
280 }
282 /* Whether we are deferring overflow warnings. */
284 bool
286 {
288 }
290 /* This is called when we fold something based on the fact that signed
291 overflow is undefined. */
293 void
295 {
297 {
300 {
303 }
304 }
307 }
308 \f
309 /* Return true if the built-in mathematical function specified by CODE
310 is odd, i.e. -f(x) == f(-x). */
312 bool
314 {
316 {
317 CASE_CFN_ASIN:
318 CASE_CFN_ASINH:
319 CASE_CFN_ATAN:
320 CASE_CFN_ATANH:
321 CASE_CFN_CASIN:
322 CASE_CFN_CASINH:
323 CASE_CFN_CATAN:
324 CASE_CFN_CATANH:
325 CASE_CFN_CBRT:
326 CASE_CFN_CPROJ:
327 CASE_CFN_CSIN:
328 CASE_CFN_CSINH:
329 CASE_CFN_CTAN:
330 CASE_CFN_CTANH:
331 CASE_CFN_ERF:
332 CASE_CFN_LLROUND:
333 CASE_CFN_LROUND:
334 CASE_CFN_ROUND:
335 CASE_CFN_SIN:
336 CASE_CFN_SINH:
337 CASE_CFN_TAN:
338 CASE_CFN_TANH:
339 CASE_CFN_TRUNC:
342 CASE_CFN_LLRINT:
343 CASE_CFN_LRINT:
344 CASE_CFN_NEARBYINT:
345 CASE_CFN_RINT:
350 }
352 }
354 /* Check whether we may negate an integer constant T without causing
355 overflow. */
357 bool
359 {
360 tree type;
369 }
371 /* Determine whether an expression T can be cheaply negated using
372 the function negate_expr without introducing undefined overflow. */
374 static bool
376 {
377 tree type;
386 {
391 /* Check that -CST will not overflow type. */
404 /* We want to canonicalize to positive real constants. Pretend
405 that only negative ones can be easily negated. */
413 {
424 }
439 /* -(A + B) -> (-B) - A. */
444 /* -(A + B) -> (-A) - B. */
448 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
459 /* INT_MIN/n * n doesn't overflow while negating one operand it does
460 if n is a power of two. */
469 /* Fall through. */
484 /* In general we can't negate B in A / B, because if A is INT_MIN and
485 B is 1, we may turn this into INT_MIN / -1 which is undefined
486 and actually traps on some architectures. */
495 /* Negate -((double)float) as (double)(-float). */
497 {
501 }
505 /* Negate -f(x) as f(-x). */
511 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
513 {
517 }
522 }
524 }
526 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
527 simplification is possible.
528 If negate_expr_p would return true for T, NULL_TREE will never be
529 returned. */
531 static tree
533 {
535 tree tem;
538 {
539 /* Convert - (~A) to A + 1. */
565 {
570 }
574 {
579 {
583 }
586 }
609 {
610 /* -(A + B) -> (-B) - A. */
614 {
618 }
620 /* -(A + B) -> (-A) - B. */
622 {
626 }
627 }
631 /* - (A - B) -> B - A */
643 /* Fall through. */
647 {
656 }
668 /* In general we can't negate B in A / B, because if A is INT_MIN and
669 B is 1, we may turn this into INT_MIN / -1 which is undefined
670 and actually traps on some architectures. */
682 /* Convert -((double)float) into (double)(-float). */
684 {
688 }
692 /* Negate -f(x) as f(-x). */
695 {
701 }
705 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
707 {
710 {
717 }
718 }
723 }
726 }
728 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
729 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
730 return NULL_TREE. */
732 static tree
734 {
736 location_t loc;
749 }
750 \f
751 /* Split a tree IN into a constant, literal and variable parts that could be
752 combined with CODE to make IN. "constant" means an expression with
753 TREE_CONSTANT but that isn't an actual constant. CODE must be a
754 commutative arithmetic operation. Store the constant part into *CONP,
755 the literal in *LITP and return the variable part. If a part isn't
756 present, set it to null. If the tree does not decompose in this way,
757 return the entire tree as the variable part and the other parts as null.
759 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
760 case, we negate an operand that was subtracted. Except if it is a
761 literal for which we use *MINUS_LITP instead.
763 If NEGATE_P is true, we are negating all of IN, again except a literal
764 for which we use *MINUS_LITP instead. If a variable part is of pointer
765 type, it is negated after converting to TYPE. This prevents us from
766 generating illegal MINUS pointer expression. LOC is the location of
767 the converted variable part.
769 If IN is itself a literal or constant, return it as appropriate.
771 Note that we do not guarantee that any of the three values will be the
772 same type as IN, but they will have the same signedness and mode. */
774 static tree
777 {
784 /* Strip any conversions that don't change the machine mode or signedness. */
793 /* We can associate addition and subtraction together (even
794 though the C standard doesn't say so) for integers because
795 the value is not affected. For reals, the value might be
796 affected, so we can't. */
799 {
805 /* First see if either of the operands is a literal, then a constant. */
818 /* If we haven't dealt with either operand, this is not a case we can
819 decompose. Otherwise, VAR is either of the ones remaining, if any. */
824 else
827 /* Now do any needed negations. */
833 {
834 /* Convert to TYPE before negating. */
837 }
838 }
841 {
842 /* -X - 1 is folded to ~X, undo that here. */
845 }
848 else
852 {
859 {
860 /* Convert to TYPE before negating. */
863 }
864 }
867 }
869 /* Re-associate trees split by the above function. T1 and T2 are
870 either expressions to associate or null. Return the new
871 expression, if any. LOC is the location of the new expression. If
872 we build an operation, do it in TYPE and with CODE. */
874 static tree
876 {
882 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
883 try to fold this since we will have infinite recursion. But do
884 deal with any NEGATE_EXPRs. */
887 {
889 {
902 }
904 {
907 }
911 }
915 }
916 \f
917 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
918 for use in int_const_binop, size_binop and size_diffop. */
920 static bool
922 {
929 {
938 }
943 }
946 /* Combine two integer constants ARG1 and ARG2 under operation CODE
947 to produce a new constant. Return NULL_TREE if we don't know how
948 to evaluate CODE at compile-time. */
950 static tree
953 {
954 wide_int res;
955 tree t;
963 {
979 {
983 else
985 }
988 /* It's unclear from the C standard whether shifts can overflow.
989 The following code ignores overflow; perhaps a C standard
990 interpretation ruling is needed. */
992 else
999 {
1003 else
1005 }
1009 else
1088 }
1096 }
1098 tree
1100 {
1102 }
1104 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1105 constant. We assume ARG1 and ARG2 have the same data type, or at least
1106 are the same kind of constant and the same machine mode. Return zero if
1107 combining the constants is not allowed in the current operating mode. */
1109 static tree
1111 {
1112 /* Sanity check for the recursive cases. */
1120 {
1126 }
1129 {
1130 machine_mode mode;
1131 REAL_VALUE_TYPE d1;
1132 REAL_VALUE_TYPE d2;
1133 REAL_VALUE_TYPE value;
1134 REAL_VALUE_TYPE result;
1138 /* The following codes are handled by real_arithmetic. */
1140 {
1151 }
1159 /* Don't perform operation if we honor signaling NaNs and
1160 either operand is a signaling NaN. */
1166 /* Don't perform operation if it would raise a division
1167 by zero exception. */
1173 /* If either operand is a NaN, just return it. Otherwise, set up
1174 for floating-point trap; we return an overflow. */
1176 {
1177 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1178 is off. */
1182 }
1184 {
1185 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1186 is off. */
1190 }
1195 /* Don't constant fold this floating point operation if
1196 the result has overflowed and flag_trapping_math. */
1204 /* Don't constant fold this floating point operation if the
1205 result may dependent upon the run-time rounding mode and
1206 flag_rounding_math is set, or if GCC's software emulation
1207 is unable to accurately represent the result. */
1217 }
1220 {
1221 FIXED_VALUE_TYPE f1;
1222 FIXED_VALUE_TYPE f2;
1223 FIXED_VALUE_TYPE result;
1228 /* The following codes are handled by fixed_arithmetic. */
1230 {
1242 {
1249 }
1254 }
1261 /* Propagate overflow flags. */
1265 }
1268 {
1277 {
1288 mpc_mul);
1302 mpc_div);
1303 /* Fallthru ... */
1309 {
1310 /* Keep this algorithm in sync with
1311 tree-complex.c:expand_complex_div_straight().
1313 Expand complex division to scalars, straightforward algorithm.
1314 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1315 t = br*br + bi*bi
1316 */
1317 tree magsquared
1321 tree t1
1325 tree t2
1332 }
1333 else
1334 {
1335 /* Keep this algorithm in sync with
1336 tree-complex.c:expand_complex_div_wide().
1338 Expand complex division to scalars, modified algorithm to minimize
1339 overflow with wide input ranges. */
1345 {
1346 /* In the TRUE branch, we compute
1347 ratio = br/bi;
1348 div = (br * ratio) + bi;
1349 tr = (ar * ratio) + ai;
1350 ti = (ai * ratio) - ar;
1351 tr = tr / div;
1352 ti = ti / div; */
1363 }
1364 else
1365 {
1366 /* In the FALSE branch, we compute
1367 ratio = d/c;
1368 divisor = (d * ratio) + c;
1369 tr = (b * ratio) + a;
1370 ti = b - (a * ratio);
1371 tr = tr / div;
1372 ti = ti / div; */
1384 }
1385 }
1390 }
1394 }
1398 {
1404 {
1410 /* It is possible that const_binop cannot handle the given
1411 code and return NULL_TREE */
1414 }
1417 }
1419 /* Shifts allow a scalar offset for a vector. */
1422 {
1428 {
1433 /* It is possible that const_binop cannot handle the given
1434 code and return NULL_TREE. */
1437 }
1440 }
1442 }
1444 /* Overload that adds a TYPE parameter to be able to dispatch
1445 to fold_relational_const. */
1447 tree
1449 {
1453 /* ??? Until we make the const_binop worker take the type of the
1454 result as argument put those cases that need it here. */
1456 {
1467 {
1483 {
1489 }
1492 }
1498 {
1523 {
1536 }
1539 }
1542 }
1547 /* Make sure type and arg0 have the same saturating flag. */
1552 }
1554 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1555 Return zero if computing the constants is not possible. */
1557 tree
1559 {
1560 /* Don't perform the operation, other than NEGATE and ABS, if
1561 flag_signaling_nans is on and the operand is a signaling NaN. */
1570 {
1571 CASE_CONVERT:
1578 /* If the source address is 0, and the source address space
1579 cannot have a valid object at 0, fold to dest type null. */
1590 {
1591 /* Can't call fold_negate_const directly here as that doesn't
1592 handle all cases and we might not be able to negate some
1593 constants. */
1598 }
1607 {
1611 }
1617 /* Perform BIT_NOT_EXPR on each element individually. */
1619 {
1621 tree elem;
1626 {
1632 }
1635 }
1657 {
1676 else
1680 {
1684 }
1687 }
1692 {
1706 {
1711 }
1714 {
1718 }
1721 }
1725 }
1728 }
1730 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1731 indicates which particular sizetype to create. */
1733 tree
1735 {
1737 }
1738 \f
1739 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1740 is a tree code. The type of the result is taken from the operands.
1741 Both must be equivalent integer types, ala int_binop_types_match_p.
1742 If the operands are constant, so is the result. */
1744 tree
1746 {
1755 /* Handle the special case of two integer constants faster. */
1757 {
1758 /* And some specific cases even faster than that. */
1760 {
1765 }
1767 {
1770 }
1772 {
1775 }
1777 /* Handle general case of two integer constants. For sizetype
1778 constant calculations we always want to know about overflow,
1779 even in the unsigned case. */
1781 }
1784 }
1786 /* Given two values, either both of sizetype or both of bitsizetype,
1787 compute the difference between the two values. Return the value
1788 in signed type corresponding to the type of the operands. */
1790 tree
1792 {
1794 tree ctype;
1799 /* If the type is already signed, just do the simple thing. */
1807 else
1810 /* If either operand is not a constant, do the conversions to the signed
1811 type and subtract. The hardware will do the right thing with any
1812 overflow in the subtraction. */
1818 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1819 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1820 overflow) and negate (which can't either). Special-case a result
1821 of zero while we're here. */
1827 else
1831 MINUS_EXPR,
1833 }
1834 \f
1835 /* A subroutine of fold_convert_const handling conversions of an
1836 INTEGER_CST to another integer type. */
1838 static tree
1840 {
1841 /* Given an integer constant, make new constant with new type,
1842 appropriately sign-extended or truncated. Use widest_int
1843 so that any extension is done according ARG1's type. */
1847 }
1849 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1850 to an integer type. */
1852 static tree
1854 {
1856 tree t;
1858 /* The following code implements the floating point to integer
1859 conversion rules required by the Java Language Specification,
1860 that IEEE NaNs are mapped to zero and values that overflow
1861 the target precision saturate, i.e. values greater than
1862 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1863 are mapped to INT_MIN. These semantics are allowed by the
1864 C and C++ standards that simply state that the behavior of
1865 FP-to-integer conversion is unspecified upon overflow. */
1867 wide_int val;
1868 REAL_VALUE_TYPE r;
1872 {
1879 }
1881 /* If R is NaN, return zero and show we have an overflow. */
1883 {
1886 }
1888 /* See if R is less than the lower bound or greater than the
1889 upper bound. */
1892 {
1896 {
1899 }
1900 }
1903 {
1906 {
1909 {
1912 }
1913 }
1914 }
1921 }
1923 /* A subroutine of fold_convert_const handling conversions of a
1924 FIXED_CST to an integer type. */
1926 static tree
1928 {
1929 tree t;
1933 /* Right shift FIXED_CST to temp by fbit. */
1937 {
1939 HOST_BITS_PER_DOUBLE_INT,
1942 /* Left shift temp to temp_trunc by fbit. */
1944 HOST_BITS_PER_DOUBLE_INT,
1946 }
1947 else
1948 {
1951 }
1953 /* If FIXED_CST is negative, we need to round the value toward 0.
1954 By checking if the fractional bits are not zero to add 1 to temp. */
1960 /* Given a fixed-point constant, make new constant with new type,
1961 appropriately sign-extended or truncated. */
1969 }
1971 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1972 to another floating point type. */
1974 static tree
1976 {
1977 REAL_VALUE_TYPE value;
1978 tree t;
1980 /* Don't perform the operation if flag_signaling_nans is on
1981 and the operand is a signaling NaN. */
1989 /* If converting an infinity or NAN to a representation that doesn't
1990 have one, set the overflow bit so that we can produce some kind of
1991 error message at the appropriate point if necessary. It's not the
1992 most user-friendly message, but it's better than nothing. */
1999 /* Regular overflow, conversion produced an infinity in a mode that
2000 can't represent them. */
2005 else
2008 }
2010 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2011 to a floating point type. */
2013 static tree
2015 {
2016 REAL_VALUE_TYPE value;
2017 tree t;
2024 }
2026 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2027 to another fixed-point type. */
2029 static tree
2031 {
2032 FIXED_VALUE_TYPE value;
2033 tree t;
2040 /* Propagate overflow flags. */
2044 }
2046 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2047 to a fixed-point type. */
2049 static tree
2051 {
2052 FIXED_VALUE_TYPE value;
2053 tree t;
2055 double_int di;
2062 else
2070 /* Propagate overflow flags. */
2074 }
2076 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2077 to a fixed-point type. */
2079 static tree
2081 {
2082 FIXED_VALUE_TYPE value;
2083 tree t;
2091 /* Propagate overflow flags. */
2095 }
2097 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2098 type TYPE. If no simplification can be done return NULL_TREE. */
2100 static tree
2102 {
2108 {
2115 }
2117 {
2124 }
2126 {
2133 }
2135 {
2138 {
2143 {
2149 }
2151 }
2152 }
2154 }
2156 /* Construct a vector of zero elements of vector type TYPE. */
2158 static tree
2160 {
2161 tree t;
2165 }
2167 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2169 bool
2171 {
2186 {
2201 }
2202 }
2204 /* Convert expression ARG to type TYPE. Used by the middle-end for
2205 simple conversions in preference to calling the front-end's convert. */
2207 tree
2209 {
2211 tree tem;
2222 {
2225 /* Handle conversions between pointers to different address spaces. */
2230 /* fall through */
2235 {
2239 }
2253 {
2257 }
2259 {
2263 }
2265 {
2269 }
2272 {
2290 }
2295 {
2299 }
2302 {
2316 }
2320 {
2329 integer_zero_node));
2331 {
2335 {
2341 }
2349 }
2353 }
2371 }
2372 fold_convert_exit:
2375 }
2376 \f
2377 /* Return false if expr can be assumed not to be an lvalue, true
2378 otherwise. */
2380 static bool
2382 {
2383 /* We only need to wrap lvalue tree codes. */
2385 {
2416 /* Assume the worst for front-end tree codes. */
2420 }
2423 }
2425 /* Return an expr equal to X but certainly not valid as an lvalue. */
2427 tree
2429 {
2430 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2431 us. */
2438 }
2440 /* When pedantic, return an expr equal to X but certainly not valid as a
2441 pedantic lvalue. Otherwise, return X. */
2443 static tree
2445 {
2447 }
2448 \f
2449 /* Given a tree comparison code, return the code that is the logical inverse.
2450 It is generally not safe to do this for floating-point comparisons, except
2451 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2452 ERROR_MARK in this case. */
2454 enum tree_code
2456 {
2462 {
2493 }
2494 }
2496 /* Similar, but return the comparison that results if the operands are
2497 swapped. This is safe for floating-point. */
2499 enum tree_code
2501 {
2503 {
2529 }
2530 }
2533 /* Convert a comparison tree code from an enum tree_code representation
2534 into a compcode bit-based encoding. This function is the inverse of
2535 compcode_to_comparison. */
2537 static enum comparison_code
2539 {
2541 {
2572 }
2573 }
2575 /* Convert a compcode bit-based encoding of a comparison operator back
2576 to GCC's enum tree_code representation. This function is the
2577 inverse of comparison_to_compcode. */
2579 static enum tree_code
2581 {
2583 {
2614 }
2615 }
2617 /* Return a tree for the comparison which is the combination of
2618 doing the AND or OR (depending on CODE) of the two operations LCODE
2619 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2620 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2621 if this makes the transformation invalid. */
2623 tree
2628 {
2635 {
2646 }
2649 {
2650 /* Eliminate unordered comparisons, as well as LTGT and ORD
2651 which are not used unless the mode has NaNs. */
2657 }
2659 {
2660 /* Check that the original operation and the optimized ones will trap
2661 under the same condition. */
2672 /* In a short-circuited boolean expression the LHS might be
2673 such that the RHS, if evaluated, will never trap. For
2674 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2675 if neither x nor y is NaN. (This is a mixed blessing: for
2676 example, the expression above will never trap, hence
2677 optimizing it to x < y would be invalid). */
2682 /* If the comparison was short-circuited, and only the RHS
2683 trapped, we may now generate a spurious trap. */
2688 /* If we changed the conditions that cause a trap, we lose. */
2691 }
2697 else
2698 {
2703 }
2704 }
2705 \f
2706 /* Return nonzero if two operands (typically of the same tree node)
2707 are necessarily equal. FLAGS modifies behavior as follows:
2709 If OEP_ONLY_CONST is set, only return nonzero for constants.
2710 This function tests whether the operands are indistinguishable;
2711 it does not test whether they are equal using C's == operation.
2712 The distinction is important for IEEE floating point, because
2713 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2714 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2716 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2717 even though it may hold multiple values during a function.
2718 This is because a GCC tree node guarantees that nothing else is
2719 executed between the evaluation of its "operands" (which may often
2720 be evaluated in arbitrary order). Hence if the operands themselves
2721 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2722 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2723 unset means assuming isochronic (or instantaneous) tree equivalence.
2724 Unless comparing arbitrary expression trees, such as from different
2725 statements, this flag can usually be left unset.
2727 If OEP_PURE_SAME is set, then pure functions with identical arguments
2728 are considered the same. It is used when the caller has other ways
2729 to ensure that global memory is unchanged in between.
2731 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2732 not values of expressions.
2734 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2735 any operand with side effect. This is unnecesarily conservative in the
2736 case we know that arg0 and arg1 are in disjoint code paths (such as in
2737 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2738 addresses with TREE_CONSTANT flag set so we know that &var == &var
2739 even if var is volatile. */
2741 int
2743 {
2744 /* When checking, verify at the outermost operand_equal_p call that
2745 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2746 hash value. */
2748 {
2750 {
2752 {
2759 }
2761 }
2762 else
2764 }
2766 /* If either is ERROR_MARK, they aren't equal. */
2772 /* Similar, if either does not have a type (like a released SSA name),
2773 they aren't equal. */
2777 /* We cannot consider pointers to different address space equal. */
2784 /* Check equality of integer constants before bailing out due to
2785 precision differences. */
2787 {
2788 /* Address of INTEGER_CST is not defined; check that we did not forget
2789 to drop the OEP_ADDRESS_OF flags. */
2792 }
2795 {
2796 /* If both types don't have the same signedness, then we can't consider
2797 them equal. We must check this before the STRIP_NOPS calls
2798 because they may change the signedness of the arguments. As pointers
2799 strictly don't have a signedness, require either two pointers or
2800 two non-pointers as well. */
2806 /* If both types don't have the same precision, then it is not safe
2807 to strip NOPs. */
2814 }
2815 #if 0
2816 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2817 sanity check once the issue is solved. */
2818 else
2819 /* Addresses of conversions and SSA_NAMEs (and many other things)
2820 are not defined. Check that we did not forget to drop the
2821 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2824 #endif
2826 /* In case both args are comparisons but with different comparison
2827 code, try to swap the comparison operands of one arg to produce
2828 a match and compare that variant. */
2832 {
2840 }
2843 {
2844 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2846 ;
2848 {
2849 /* If we are interested in comparing addresses ignore
2850 MEM_REF wrappings of the base that can appear just for
2851 TBAA reasons. */
2865 }
2866 else
2868 }
2870 /* When not checking adddresses, this is needed for conversions and for
2871 COMPONENT_REF. Might as well play it safe and always test this. */
2878 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2879 We don't care about side effects in that case because the SAVE_EXPR
2880 takes care of that for us. In all other cases, two expressions are
2881 equal if they have no side effects. If we have two identical
2882 expressions with side effects that should be treated the same due
2883 to the only side effects being identical SAVE_EXPR's, that will
2884 be detected in the recursive calls below.
2885 If we are taking an invariant address of two identical objects
2886 they are necessarily equal as well. */
2893 /* Next handle constant cases, those for which we can return 1 even
2894 if ONLY_CONST is set. */
2897 {
2911 {
2912 /* If we do not distinguish between signed and unsigned zero,
2913 consider them equal. */
2916 }
2920 {
2927 {
2931 }
2933 }
2937 flags)
2939 flags));
2950 flags | OEP_ADDRESS_OF
2953 /* In GIMPLE empty constructors are allowed in initializers of
2954 aggregates. */
2959 }
2964 /* Define macros to test an operand from arg0 and arg1 for equality and a
2965 variant that allows null and views null as being different from any
2966 non-null value. In the latter case, if either is null, the both
2967 must be; otherwise, do the normal comparison. */
2968 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2969 TREE_OPERAND (arg1, N), flags)
2971 #define OP_SAME_WITH_NULL(N) \
2972 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2973 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2976 {
2978 /* Two conversions are equal only if signedness and modes match. */
2980 {
2981 CASE_CONVERT:
2989 }
2999 /* For commutative ops, allow the other order. */
3007 /* If either of the pointer (or reference) expressions we are
3008 dereferencing contain a side effect, these cannot be equal,
3009 but their addresses can be. */
3016 {
3026 /* Require the same offset. */
3032 /* Fallthru. */
3040 {
3041 /* Require equal access sizes */
3047 flags)))
3049 /* Verify that access happens in similar types. */
3052 /* Verify that accesses are TBAA compatible. */
3061 /* Verify that alignment is compatible. */
3065 }
3068 /* TARGET_MEM_REF require equal extra operands. */
3079 /* Compare the array index by value if it is constant first as we
3080 may have different types but same value here. */
3086 /* Compare low bound and element size as with OEP_ADDRESS_OF
3087 we have to account for the offset of the ref. */
3092 array_ref_low_bound
3096 array_ref_element_size
3098 flags))));
3101 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3102 may be NULL when we're called to compare MEM_EXPRs. */
3117 }
3121 {
3123 /* Be sure we pass right ADDRESS_OF flag. */
3141 /* The multiplcation operands are commutative. */
3142 /* FALLTHRU */
3150 /* Otherwise take into account this is a commutative operation. */
3169 }
3173 {
3177 /* If not both CALL_EXPRs are either internal or normal function
3178 functions, then they are not equal. */
3181 {
3182 /* If the CALL_EXPRs call different internal functions, then they
3183 are not equal. */
3186 }
3187 else
3188 {
3189 /* If the CALL_EXPRs call different functions, then they are not
3190 equal. */
3192 flags))
3194 }
3196 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3197 {
3201 else
3205 }
3207 /* Now see if all the arguments are the same. */
3208 {
3219 /* If we get here and both argument lists are exhausted
3220 then the CALL_EXPRs are equal. */
3222 }
3225 }
3228 /* Consider __builtin_sqrt equal to sqrt. */
3236 {
3237 /* In GIMPLE constructors are used only to build vectors from
3238 elements. Individual elements in the constructor must be
3239 indexed in increasing order and form an initial sequence.
3241 We make no effort to compare constructors in generic.
3242 (see sem_variable::equals in ipa-icf which can do so for
3243 constants). */
3248 /* Be sure that vectors constructed have the same representation.
3249 We only tested element precision and modes to match.
3250 Vectors may be BLKmode and thus also check that the number of
3251 parts match. */
3264 {
3269 /* In GIMPLE the indexes can be either NULL or matching i.
3270 Double check this so we won't get false
3271 positives for GENERIC. */
3279 }
3281 }
3286 }
3288 #undef OP_SAME
3289 #undef OP_SAME_WITH_NULL
3290 }
3291 \f
3292 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3293 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3295 When in doubt, return 0. */
3297 static int
3299 {
3311 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3312 and see if the inner values are the same. This removes any
3313 signedness comparison, which doesn't matter here. */
3320 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3321 actual comparison operand, ARG0.
3323 First throw away any conversions to wider types
3324 already present in the operands. */
3333 {
3336 /* Make sure shorter operand is extended the right way
3337 to match the longer operand. */
3343 }
3346 }
3347 \f
3348 /* See if ARG is an expression that is either a comparison or is performing
3349 arithmetic on comparisons. The comparisons must only be comparing
3350 two different values, which will be stored in *CVAL1 and *CVAL2; if
3351 they are nonzero it means that some operands have already been found.
3352 No variables may be used anywhere else in the expression except in the
3353 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3354 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3356 If this is true, return 1. Otherwise, return zero. */
3358 static int
3360 {
3364 /* We can handle some of the tcc_expression cases here. */
3374 {
3375 /* If we've already found a CVAL1 or CVAL2, this expression is
3376 two complex to handle. */
3382 }
3385 {
3408 /* First see if we can handle the first operand, then the second. For
3409 the second operand, we know *CVAL1 can't be zero. It must be that
3410 one side of the comparison is each of the values; test for the
3411 case where this isn't true by failing if the two operands
3412 are the same. */
3421 ;
3425 ;
3426 else
3430 ;
3434 ;
3435 else
3442 }
3443 }
3444 \f
3445 /* ARG is a tree that is known to contain just arithmetic operations and
3446 comparisons. Evaluate the operations in the tree substituting NEW0 for
3447 any occurrence of OLD0 as an operand of a comparison and likewise for
3448 NEW1 and OLD1. */
3450 static tree
3453 {
3458 /* We can handle some of the tcc_expression cases here. */
3466 {
3481 {
3500 }
3501 /* Fall through - ??? */
3504 {
3508 /* We need to check both for exact equality and tree equality. The
3509 former will be true if the operand has a side-effect. In that
3510 case, we know the operand occurred exactly once. */
3523 }
3527 }
3528 }
3529 \f
3530 /* Return a tree for the case when the result of an expression is RESULT
3531 converted to TYPE and OMITTED was previously an operand of the expression
3532 but is now not needed (e.g., we folded OMITTED * 0).
3534 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3535 the conversion of RESULT to TYPE. */
3537 tree
3539 {
3542 /* If the resulting operand is an empty statement, just return the omitted
3543 statement casted to void. */
3553 }
3555 /* Return a tree for the case when the result of an expression is RESULT
3556 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3557 of the expression but are now not needed.
3559 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3560 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3561 evaluated before OMITTED2. Otherwise, if neither has side effects,
3562 just do the conversion of RESULT to TYPE. */
3564 tree
3567 {
3576 }
3578 \f
3579 /* Return a simplified tree node for the truth-negation of ARG. This
3580 never alters ARG itself. We assume that ARG is an operation that
3581 returns a truth value (0 or 1).
3583 FIXME: one would think we would fold the result, but it causes
3584 problems with the dominator optimizer. */
3586 static tree
3588 {
3593 /* If this is a comparison, we can simply invert it, except for
3594 floating-point non-equality comparisons, in which case we just
3595 enclose a TRUTH_NOT_EXPR around what we have. */
3598 {
3601 && flag_trapping_math
3615 }
3618 {
3637 /* Here we can invert either operand. We invert the first operand
3638 unless the second operand is a TRUTH_NOT_EXPR in which case our
3639 result is the XOR of the first operand with the inside of the
3640 negation of the second operand. */
3645 else
3668 {
3675 /* A COND_EXPR may have a throw as one operand, which
3676 then has void type. Just leave void operands
3677 as they are. */
3683 }
3695 CASE_CONVERT:
3699 /* ... fall through ... */
3721 }
3722 }
3724 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3725 assume that ARG is an operation that returns a truth value (0 or 1
3726 for scalars, 0 or -1 for vectors). Return the folded expression if
3727 folding is successful. Otherwise, return NULL_TREE. */
3729 static tree
3731 {
3734 ? BIT_NOT_EXPR
3737 }
3739 /* Return a simplified tree node for the truth-negation of ARG. This
3740 never alters ARG itself. We assume that ARG is an operation that
3741 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3743 tree
3745 {
3751 ? BIT_NOT_EXPR
3754 }
3756 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3757 with code CODE. This optimization is unsafe. */
3758 static tree
3761 {
3765 /* (A / C) +- (B / C) -> (A +- B) / C. */
3775 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3780 {
3792 }
3795 }
3796 \f
3797 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3798 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3799 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3800 is the original memory reference used to preserve the alias set of
3801 the access. */
3803 static tree
3807 {
3813 build_int_cst
3817 {
3824 }
3839 }
3841 /* Optimize a bit-field compare.
3843 There are two cases: First is a compare against a constant and the
3844 second is a comparison of two items where the fields are at the same
3845 bit position relative to the start of a chunk (byte, halfword, word)
3846 large enough to contain it. In these cases we can avoid the shift
3847 implicit in bitfield extractions.
3849 For constants, we emit a compare of the shifted constant with the
3850 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3851 compared. For two fields at the same position, we do the ANDs with the
3852 similar mask and compare the result of the ANDs.
3854 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3855 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3856 are the left and right operands of the comparison, respectively.
3858 If the optimization described above can be done, we return the resulting
3859 tree. Otherwise we return zero. */
3861 static tree
3864 {
3867 tree unsigned_type;
3874 tree mask;
3875 tree offset;
3877 /* Get all the information about the extractions being done. If the bit size
3878 if the same as the size of the underlying object, we aren't doing an
3879 extraction at all and so can do nothing. We also don't want to
3880 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3881 then will no longer be able to replace it. */
3890 else
3891 {
3892 /* If this is not a constant, we can only do something if bit positions,
3893 sizes, signedness and storage order are the same. */
3894 rinner
3902 }
3904 /* Honor the C++ memory model and mimic what RTL expansion does. */
3908 {
3912 }
3914 /* See if we can find a mode to refer to this field. We should be able to,
3915 but fail if we can't. */
3924 /* Set signed and unsigned types of the precision of this mode for the
3925 shifts below. */
3928 /* Compute the bit position and size for the new reference and our offset
3929 within it. If the new reference is the same size as the original, we
3930 won't optimize anything, so return zero. */
3940 /* Make the mask to be used against the extracted field. */
3947 /* If not comparing with constant, just rework the comparison
3948 and return. */
3952 unsigned_type,
3955 mask),
3958 unsigned_type,
3961 mask));
3963 /* Otherwise, we are handling the constant case. See if the constant is too
3964 big for the field. Warn and return a tree for 0 (false) if so. We do
3965 this not only for its own sake, but to avoid having to test for this
3966 error case below. If we didn't, we might generate wrong code.
3968 For unsigned fields, the constant shifted right by the field length should
3969 be all zero. For signed fields, the high-order bits should agree with
3970 the sign bit. */
3973 {
3975 {
3979 }
3980 }
3981 else
3982 {
3985 {
3989 }
3990 }
3992 /* Single-bit compares should always be against zero. */
3994 {
3997 }
3999 /* Make a new bitfield reference, shift the constant over the
4000 appropriate number of bits and mask it with the computed mask
4001 (in case this was a signed field). If we changed it, make a new one. */
4009 mask);
4014 }
4015 \f
4016 /* Subroutine for fold_truth_andor_1: decode a field reference.
4018 If EXP is a comparison reference, we return the innermost reference.
4020 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4021 set to the starting bit number.
4023 If the innermost field can be completely contained in a mode-sized
4024 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4026 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4027 otherwise it is not changed.
4029 *PUNSIGNEDP is set to the signedness of the field.
4031 *PREVERSEP is set to the storage order of the field.
4033 *PMASK is set to the mask used. This is either contained in a
4034 BIT_AND_EXPR or derived from the width of the field.
4036 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4038 Return 0 if this is not a component reference or is one that we can't
4039 do anything with. */
4041 static tree
4046 {
4051 tree unsigned_type;
4054 /* All the optimizations using this function assume integer fields.
4055 There are problems with FP fields since the type_for_size call
4056 below can fail for, e.g., XFmode. */
4060 /* We are interested in the bare arrangement of bits, so strip everything
4061 that doesn't affect the machine mode. However, record the type of the
4062 outermost expression if it may matter below. */
4069 {
4075 }
4086 /* If the number of bits in the reference is the same as the bitsize of
4087 the outer type, then the outer type gives the signedness. Otherwise
4088 (in case of a small bitfield) the signedness is unchanged. */
4092 /* Compute the mask to access the bitfield. */
4101 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4109 }
4111 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4112 bit positions and MASK is SIGNED. */
4114 static int
4116 {
4120 /* If this function returns true when the type of the mask is
4121 UNSIGNED, then there will be errors. In particular see
4122 gcc.c-torture/execute/990326-1.c. There does not appear to be
4123 any documentation paper trail as to why this is so. But the pre
4124 wide-int worked with that restriction and it has been preserved
4125 here. */
4130 }
4132 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4133 represents the sign bit of EXP's type. If EXP represents a sign
4134 or zero extension, also test VAL against the unextended type.
4135 The return value is the (sub)expression whose sign bit is VAL,
4136 or NULL_TREE otherwise. */
4138 tree
4140 {
4142 tree t;
4144 /* Tree EXP must have an integral type. */
4149 /* Tree VAL must be an integer constant. */
4158 /* Handle extension from a narrower type. */
4164 }
4166 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4167 to be evaluated unconditionally. */
4169 static int
4171 {
4172 /* Strip any conversions that don't change the machine mode. */
4181 /* Don't regard global variables as simple. They may be
4182 allocated in ways unknown to the compiler (shared memory,
4183 #pragma weak, etc). */
4186 /* Weakrefs are not safe to be read, since they can be NULL.
4187 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4188 have DECL_WEAK flag set. */
4190 /* Loading a static variable is unduly expensive, but global
4191 registers aren't expensive. */
4193 }
4195 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4196 to be evaluated unconditionally.
4197 I addition to simple_operand_p, we assume that comparisons, conversions,
4198 and logic-not operations are simple, if their operands are simple, too. */
4200 static bool
4202 {
4222 }
4224 \f
4225 /* The following functions are subroutines to fold_range_test and allow it to
4226 try to change a logical combination of comparisons into a range test.
4228 For example, both
4229 X == 2 || X == 3 || X == 4 || X == 5
4230 and
4231 X >= 2 && X <= 5
4232 are converted to
4233 (unsigned) (X - 2) <= 3
4235 We describe each set of comparisons as being either inside or outside
4236 a range, using a variable named like IN_P, and then describe the
4237 range with a lower and upper bound. If one of the bounds is omitted,
4238 it represents either the highest or lowest value of the type.
4240 In the comments below, we represent a range by two numbers in brackets
4241 preceded by a "+" to designate being inside that range, or a "-" to
4242 designate being outside that range, so the condition can be inverted by
4243 flipping the prefix. An omitted bound is represented by a "-". For
4244 example, "- [-, 10]" means being outside the range starting at the lowest
4245 possible value and ending at 10, in other words, being greater than 10.
4246 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4247 always false.
4249 We set up things so that the missing bounds are handled in a consistent
4250 manner so neither a missing bound nor "true" and "false" need to be
4251 handled using a special case. */
4253 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4254 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4255 and UPPER1_P are nonzero if the respective argument is an upper bound
4256 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4257 must be specified for a comparison. ARG1 will be converted to ARG0's
4258 type if both are specified. */
4260 static tree
4263 {
4264 tree tem;
4268 /* If neither arg represents infinity, do the normal operation.
4269 Else, if not a comparison, return infinity. Else handle the special
4270 comparison rules. Note that most of the cases below won't occur, but
4271 are handled for consistency. */
4274 {
4279 }
4284 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4285 for neither. In real maths, we cannot assume open ended ranges are
4286 the same. But, this is computer arithmetic, where numbers are finite.
4287 We can therefore make the transformation of any unbounded range with
4288 the value Z, Z being greater than any representable number. This permits
4289 us to treat unbounded ranges as equal. */
4293 {
4314 }
4317 }
4318 \f
4319 /* Helper routine for make_range. Perform one step for it, return
4320 new expression if the loop should continue or NULL_TREE if it should
4321 stop. */
4323 tree
4327 {
4333 {
4335 /* We can only do something if the range is testing for zero. */
4344 /* We can only do something if the range is testing for zero
4345 and if the second operand is an integer constant. Note that
4346 saying something is "in" the range we make is done by
4347 complementing IN_P since it will set in the initial case of
4348 being not equal to zero; "out" is leaving it alone. */
4355 {
4376 }
4378 /* If this is an unsigned comparison, we also know that EXP is
4379 greater than or equal to zero. We base the range tests we make
4380 on that fact, so we record it here so we can parse existing
4381 range tests. We test arg0_type since often the return type
4382 of, e.g. EQ_EXPR, is boolean. */
4384 {
4388 NULL_TREE))
4393 /* If the high bound is missing, but we have a nonzero low
4394 bound, reverse the range so it goes from zero to the low bound
4395 minus 1. */
4397 {
4402 }
4403 }
4411 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4412 low and high are non-NULL, then normalize will DTRT. */
4415 {
4420 }
4422 /* (-x) IN [a,b] -> x in [-b, -a] */
4434 /* ~ X -> -X - 1 */
4443 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4444 move a constant to the other side. */
4449 /* If EXP is signed, any overflow in the computation is undefined,
4450 so we don't worry about it so long as our computations on
4451 the bounds don't overflow. For unsigned, overflow is defined
4452 and this is exactly the right thing. */
4464 normalize:
4465 /* Check for an unsigned range which has wrapped around the maximum
4466 value thus making n_high < n_low, and normalize it. */
4468 {
4474 /* If the range is of the form +/- [ x+1, x ], we won't
4475 be able to normalize it. But then, it represents the
4476 whole range or the empty set, so make it
4477 +/- [ -, - ]. */
4481 else
4483 }
4484 else
4492 CASE_CONVERT:
4510 /* If we're converting arg0 from an unsigned type, to exp,
4511 a signed type, we will be doing the comparison as unsigned.
4512 The tests above have already verified that LOW and HIGH
4513 are both positive.
4515 So we have to ensure that we will handle large unsigned
4516 values the same way that the current signed bounds treat
4517 negative values. */
4520 {
4521 tree high_positive;
4522 tree equiv_type;
4523 /* For fixed-point modes, we need to pass the saturating flag
4524 as the 2nd parameter. */
4526 equiv_type
4529 else
4530 equiv_type
4533 /* A range without an upper bound is, naturally, unbounded.
4534 Since convert would have cropped a very large value, use
4535 the max value for the destination type. */
4536 high_positive
4543 high_positive),
4546 /* If the low bound is specified, "and" the range with the
4547 range for which the original unsigned value will be
4548 positive. */
4550 {
4553 integer_zero_node),
4554 high_positive))
4558 }
4559 else
4560 {
4561 /* Otherwise, "or" the range with the range of the input
4562 that will be interpreted as negative. */
4565 integer_zero_node),
4566 high_positive))
4570 }
4571 }
4580 }
4581 }
4583 /* Given EXP, a logical expression, set the range it is testing into
4584 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4585 actually being tested. *PLOW and *PHIGH will be made of the same
4586 type as the returned expression. If EXP is not a comparison, we
4587 will most likely not be returning a useful value and range. Set
4588 *STRICT_OVERFLOW_P to true if the return value is only valid
4589 because signed overflow is undefined; otherwise, do not change
4590 *STRICT_OVERFLOW_P. */
4592 tree
4595 {
4603 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4604 and see if we can refine the range. Some of the cases below may not
4605 happen, but it doesn't seem worth worrying about this. We "continue"
4606 the outer loop when we've changed something; otherwise we "break"
4607 the switch, which will "break" the while. */
4613 {
4619 {
4627 }
4636 }
4638 /* If EXP is a constant, we can evaluate whether this is true or false. */
4640 {
4647 }
4651 }
4652 \f
4653 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4654 type, TYPE, return an expression to test if EXP is in (or out of, depending
4655 on IN_P) the range. Return 0 if the test couldn't be created. */
4657 tree
4660 {
4663 /* Disable this optimization for function pointer expressions
4664 on targets that require function pointer canonicalization. */
4671 {
4677 }
4695 {
4697 {
4701 }
4703 }
4705 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4707 {
4711 {
4713 {
4716 etype
4718 else
4721 }
4724 }
4725 }
4727 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4728 This requires wrap-around arithmetics for the type of the expression.
4729 First make sure that arithmetics in this type is valid, then make sure
4730 that it wraps around. */
4736 {
4739 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4740 for the type in question, as we rely on this here. */
4750 else
4752 }
4762 {
4764 {
4769 }
4771 }
4779 }
4780 \f
4781 /* Return the predecessor of VAL in its type, handling the infinite case. */
4783 static tree
4785 {
4791 else
4794 }
4796 /* Return the successor of VAL in its type, handling the infinite case. */
4798 static tree
4800 {
4806 else
4809 }
4811 /* Given two ranges, see if we can merge them into one. Return 1 if we
4812 can, 0 if we can't. Set the output range into the specified parameters. */
4814 bool
4817 {
4821 tree tem;
4831 /* Make range 0 be the range that starts first, or ends last if they
4832 start at the same value. Swap them if it isn't. */
4835 || (lowequal
4838 {
4842 }
4844 /* Now flag two cases, whether the ranges are disjoint or whether the
4845 second range is totally subsumed in the first. Note that the tests
4846 below are simplified by the ones above. */
4852 /* We now have four cases, depending on whether we are including or
4853 excluding the two ranges. */
4855 {
4856 /* If they don't overlap, the result is false. If the second range
4857 is a subset it is the result. Otherwise, the range is from the start
4858 of the second to the end of the first. */
4863 else
4865 }
4868 {
4869 /* If they don't overlap, the result is the first range. If they are
4870 equal, the result is false. If the second range is a subset of the
4871 first, and the ranges begin at the same place, we go from just after
4872 the end of the second range to the end of the first. If the second
4873 range is not a subset of the first, or if it is a subset and both
4874 ranges end at the same place, the range starts at the start of the
4875 first range and ends just before the second range.
4876 Otherwise, we can't describe this as a single range. */
4882 {
4887 {
4888 /* We are in the weird situation where high0 > high1 but
4889 high1 has no successor. Punt. */
4891 }
4892 }
4894 {
4899 {
4900 /* low0 < low1 but low1 has no predecessor. Punt. */
4902 }
4903 }
4904 else
4906 }
4909 {
4910 /* If they don't overlap, the result is the second range. If the second
4911 is a subset of the first, the result is false. Otherwise,
4912 the range starts just after the first range and ends at the
4913 end of the second. */
4918 else
4919 {
4924 {
4925 /* high1 > high0 but high0 has no successor. Punt. */
4927 }
4928 }
4929 }
4931 else
4932 {
4933 /* The case where we are excluding both ranges. Here the complex case
4934 is if they don't overlap. In that case, the only time we have a
4935 range is if they are adjacent. If the second is a subset of the
4936 first, the result is the first. Otherwise, the range to exclude
4937 starts at the beginning of the first range and ends at the end of the
4938 second. */
4940 {
4945 else
4946 {
4947 /* Canonicalize - [min, x] into - [-, x]. */
4950 {
4955 /* FALLTHROUGH */
4968 }
4970 /* Canonicalize - [x, max] into - [x, -]. */
4973 {
4978 /* FALLTHROUGH */
4994 }
4996 /* The ranges might be also adjacent between the maximum and
4997 minimum values of the given type. For
4998 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4999 return + [x + 1, y - 1]. */
5001 {
5008 }
5009 else
5011 }
5012 }
5015 else
5017 }
5021 }
5022 \f
5024 /* Subroutine of fold, looking inside expressions of the form
5025 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5026 of the COND_EXPR. This function is being used also to optimize
5027 A op B ? C : A, by reversing the comparison first.
5029 Return a folded expression whose code is not a COND_EXPR
5030 anymore, or NULL_TREE if no folding opportunity is found. */
5032 static tree
5035 {
5040 tree tem;
5045 /* If we have A op 0 ? A : -A, consider applying the following
5046 transformations:
5048 A == 0? A : -A same as -A
5049 A != 0? A : -A same as A
5050 A >= 0? A : -A same as abs (A)
5051 A > 0? A : -A same as abs (A)
5052 A <= 0? A : -A same as -abs (A)
5053 A < 0? A : -A same as -abs (A)
5055 None of these transformations work for modes with signed
5056 zeros. If A is +/-0, the first two transformations will
5057 change the sign of the result (from +0 to -0, or vice
5058 versa). The last four will fix the sign of the result,
5059 even though the original expressions could be positive or
5060 negative, depending on the sign of A.
5062 Note that all these transformations are correct if A is
5063 NaN, since the two alternatives (A and -A) are also NaNs. */
5070 /* In the case that A is of the form X-Y, '-A' (arg2) may
5071 have already been folded to Y-X, check for that. */
5079 {
5093 /* Fall through. */
5113 }
5115 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5116 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5117 both transformations are correct when A is NaN: A != 0
5118 is then true, and A == 0 is false. */
5122 {
5127 }
5129 /* Try some transformations of A op B ? A : B.
5131 A == B? A : B same as B
5132 A != B? A : B same as A
5133 A >= B? A : B same as max (A, B)
5134 A > B? A : B same as max (B, A)
5135 A <= B? A : B same as min (A, B)
5136 A < B? A : B same as min (B, A)
5138 As above, these transformations don't work in the presence
5139 of signed zeros. For example, if A and B are zeros of
5140 opposite sign, the first two transformations will change
5141 the sign of the result. In the last four, the original
5142 expressions give different results for (A=+0, B=-0) and
5143 (A=-0, B=+0), but the transformed expressions do not.
5145 The first two transformations are correct if either A or B
5146 is a NaN. In the first transformation, the condition will
5147 be false, and B will indeed be chosen. In the case of the
5148 second transformation, the condition A != B will be true,
5149 and A will be chosen.
5151 The conversions to max() and min() are not correct if B is
5152 a number and A is not. The conditions in the original
5153 expressions will be false, so all four give B. The min()
5154 and max() versions would give a NaN instead. */
5157 /* Avoid these transformations if the COND_EXPR may be used
5158 as an lvalue in the C++ front-end. PR c++/19199. */
5159 && (in_gimple_form
5165 {
5170 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
5172 {
5176 }
5179 {
5188 /* In C++ a ?: expression can be an lvalue, so put the
5189 operand which will be used if they are equal first
5190 so that we can convert this back to the
5191 corresponding COND_EXPR. */
5193 {
5202 }
5209 {
5218 }
5233 }
5234 }
5236 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5237 we might still be able to simplify this. For example,
5238 if C1 is one less or one more than C2, this might have started
5239 out as a MIN or MAX and been transformed by this function.
5240 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5246 {
5250 /* We can replace A with C1 in this case. */
5255 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
5256 MIN_EXPR, to preserve the signedness of the comparison. */
5258 OEP_ONLY_CONST)
5262 OEP_ONLY_CONST))
5263 {
5266 arg2));
5269 }
5273 /* If C1 is C2 - 1, this is min(A, C2), with the same care
5274 as above. */
5276 OEP_ONLY_CONST)
5280 OEP_ONLY_CONST))
5281 {
5284 arg2));
5287 }
5291 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
5292 MAX_EXPR, to preserve the signedness of the comparison. */
5294 OEP_ONLY_CONST)
5298 OEP_ONLY_CONST))
5299 {
5302 arg2));
5304 }
5308 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
5310 OEP_ONLY_CONST)
5314 OEP_ONLY_CONST))
5315 {
5318 arg2));
5320 }
5326 }
5329 }
5332 \f
5333 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5334 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5335 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5336 false) >= 2)
5337 #endif
5339 /* EXP is some logical combination of boolean tests. See if we can
5340 merge it into some range test. Return the new tree if so. */
5342 static tree
5345 {
5361 /* If this is an OR operation, invert both sides; we will invert
5362 again at the end. */
5366 /* If both expressions are the same, if we can merge the ranges, and we
5367 can build the range test, return it or it inverted. If one of the
5368 ranges is always true or always false, consider it to be the same
5369 expression as the other. */
5377 {
5381 }
5383 /* On machines where the branch cost is expensive, if this is a
5384 short-circuited branch and the underlying object on both sides
5385 is the same, make a non-short-circuit operation. */
5391 {
5392 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5393 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5394 which cases we can't do this. */
5402 {
5411 {
5414 WARN_STRICT_OVERFLOW_COMPARISON);
5418 }
5419 }
5420 }
5423 }
5424 \f
5425 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5426 bit value. Arrange things so the extra bits will be set to zero if and
5427 only if C is signed-extended to its full width. If MASK is nonzero,
5428 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5430 static tree
5432 {
5435 tree temp;
5440 /* We work by getting just the sign bit into the low-order bit, then
5441 into the high-order bit, then sign-extend. We then XOR that value
5442 with C. */
5445 /* We must use a signed type in order to get an arithmetic right shift.
5446 However, we must also avoid introducing accidental overflows, so that
5447 a subsequent call to integer_zerop will work. Hence we must
5448 do the type conversion here. At this point, the constant is either
5449 zero or one, and the conversion to a signed type can never overflow.
5450 We could get an overflow if this conversion is done anywhere else. */
5459 /* If necessary, convert the type back to match the type of C. */
5464 }
5465 \f
5466 /* For an expression that has the form
5467 (A && B) || ~B
5468 or
5469 (A || B) && ~B,
5470 we can drop one of the inner expressions and simplify to
5471 A || ~B
5472 or
5473 A && ~B
5474 LOC is the location of the resulting expression. OP is the inner
5475 logical operation; the left-hand side in the examples above, while CMPOP
5476 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5477 removing a condition that guards another, as in
5478 (A != NULL && A->...) || A == NULL
5479 which we must not transform. If RHS_ONLY is true, only eliminate the
5480 right-most operand of the inner logical operation. */
5482 static tree
5485 {
5503 {
5506 {
5509 }
5510 }
5512 {
5515 {
5518 }
5519 }
5534 }
5536 /* Find ways of folding logical expressions of LHS and RHS:
5537 Try to merge two comparisons to the same innermost item.
5538 Look for range tests like "ch >= '0' && ch <= '9'".
5539 Look for combinations of simple terms on machines with expensive branches
5540 and evaluate the RHS unconditionally.
5542 For example, if we have p->a == 2 && p->b == 4 and we can make an
5543 object large enough to span both A and B, we can do this with a comparison
5544 against the object ANDed with the a mask.
5546 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5547 operations to do this with one comparison.
5549 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5550 function and the one above.
5552 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5553 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5555 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5556 two operands.
5558 We return the simplified tree or 0 if no optimization is possible. */
5560 static tree
5563 {
5564 /* If this is the "or" of two comparisons, we can do something if
5565 the comparisons are NE_EXPR. If this is the "and", we can do something
5566 if the comparisons are EQ_EXPR. I.e.,
5567 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5569 WANTED_CODE is this operation code. For single bit fields, we can
5570 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5571 comparison for one-bit fields. */
5592 /* Start by getting the comparison codes. Fail if anything is volatile.
5593 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5594 it were surrounded with a NE_EXPR. */
5603 {
5607 }
5610 {
5614 }
5625 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5628 {
5631 {
5636 }
5639 {
5645 }
5646 }
5651 /* If the RHS can be evaluated unconditionally and its operands are
5652 simple, it wins to evaluate the RHS unconditionally on machines
5653 with expensive branches. In this case, this isn't a comparison
5654 that can be merged. */
5661 {
5662 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5673 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5683 }
5685 /* See if the comparisons can be merged. Then get all the parameters for
5686 each side. */
5711 /* It must be true that the inner operation on the lhs of each
5712 comparison must be the same if we are to be able to do anything.
5713 Then see if we have constants. If not, the same must be true for
5714 the rhs's. */
5723 {
5726 }
5731 else
5734 /* If either comparison code is not correct for our logical operation,
5735 fail. However, we can convert a one-bit comparison against zero into
5736 the opposite comparison against that bit being set in the field. */
5740 {
5742 {
5743 /* Make the left operand unsigned, since we are only interested
5744 in the value of one bit. Otherwise we are doing the wrong
5745 thing below. */
5748 }
5749 else
5751 }
5753 /* This is analogous to the code for l_const above. */
5755 {
5757 {
5760 }
5761 else
5763 }
5765 /* See if we can find a mode that contains both fields being compared on
5766 the left. If we can't, fail. Otherwise, update all constants and masks
5767 to be relative to a field of that size. */
5772 volatilep);
5782 {
5785 }
5793 {
5800 {
5804 }
5805 }
5807 {
5814 {
5818 }
5819 }
5821 /* If the right sides are not constant, do the same for it. Also,
5822 disallow this optimization if a size or signedness mismatch occurs
5823 between the left and right sides. */
5825 {
5828 /* Make sure the two fields on the right
5829 correspond to the left without being swapped. */
5837 volatilep);
5847 {
5850 }
5859 /* Make a mask that corresponds to both fields being compared.
5860 Do this for both items being compared. If the operands are the
5861 same size and the bits being compared are in the same position
5862 then we can do this by masking both and comparing the masked
5863 results. */
5867 {
5881 }
5883 /* There is still another way we can do something: If both pairs of
5884 fields being compared are adjacent, we may be able to make a wider
5885 field containing them both.
5887 Note that we still must mask the lhs/rhs expressions. Furthermore,
5888 the mask must be shifted to account for the shift done by
5889 make_bit_field_ref. */
5894 {
5895 tree type;
5911 /* Convert to the smaller type before masking out unwanted bits. */
5914 {
5916 {
5920 }
5922 {
5926 }
5927 }
5936 }
5939 }
5941 /* Handle the case of comparisons with constants. If there is something in
5942 common between the masks, those bits of the constants must be the same.
5943 If not, the condition is always false. Test for this to avoid generating
5944 incorrect code below. */
5949 {
5951 {
5954 }
5955 else
5956 {
5959 }
5960 }
5962 /* Construct the expression we will return. First get the component
5963 reference we will make. Unless the mask is all ones the width of
5964 that field, perform the mask operation. Then compare with the
5965 merged constant. */
5976 }
5977 \f
5978 /* T is an integer expression that is being multiplied, divided, or taken a
5979 modulus (CODE says which and what kind of divide or modulus) by a
5980 constant C. See if we can eliminate that operation by folding it with
5981 other operations already in T. WIDE_TYPE, if non-null, is a type that
5982 should be used for the computation if wider than our type.
5984 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5985 (X * 2) + (Y * 4). We must, however, be assured that either the original
5986 expression would not overflow or that overflow is undefined for the type
5987 in the language in question.
5989 If we return a non-null expression, it is an equivalent form of the
5990 original computation, but need not be in the original type.
5992 We set *STRICT_OVERFLOW_P to true if the return values depends on
5993 signed overflow being undefined. Otherwise we do not change
5994 *STRICT_OVERFLOW_P. */
5996 static tree
5999 {
6000 /* To avoid exponential search depth, refuse to allow recursion past
6001 three levels. Beyond that (1) it's highly unlikely that we'll find
6002 something interesting and (2) we've probably processed it before
6003 when we built the inner expression. */
6006 tree ret;
6011 depth++;
6013 depth--;
6016 }
6018 static tree
6021 {
6032 /* Don't deal with constants of zero here; they confuse the code below. */
6042 /* Note that we need not handle conditional operations here since fold
6043 already handles those cases. So just do arithmetic here. */
6045 {
6047 /* For a constant, we can always simplify if we are a multiply
6048 or (for divide and modulus) if it is a multiple of our constant. */
6051 {
6054 /* If the multiplication overflowed, we lost information on it.
6055 See PR68142 and PR69845. */
6059 }
6063 /* If op0 is an expression ... */
6069 /* ... and has wrapping overflow, and its type is smaller
6070 than ctype, then we cannot pass through as widening. */
6075 /* ... or this is a truncation (t is narrower than op0),
6076 then we cannot pass through this narrowing. */
6079 /* ... or signedness changes for division or modulus,
6080 then we cannot pass through this conversion. */
6084 /* ... or has undefined overflow while the converted to
6085 type has not, we cannot do the operation in the inner type
6086 as that would introduce undefined overflow. */
6092 /* Pass the constant down and see if we can make a simplification. If
6093 we can, replace this expression with the inner simplification for
6094 possible later conversion to our or some other type. */
6099 code == MULT_EXPR
6101 strict_overflow_p))))
6106 /* If widening the type changes it from signed to unsigned, then we
6107 must avoid building ABS_EXPR itself as unsigned. */
6109 {
6113 {
6116 }
6118 }
6119 /* If the constant is negative, we cannot simplify this. */
6122 /* FALLTHROUGH */
6124 /* For division and modulus, type can't be unsigned, as e.g.
6125 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6126 For signed types, even with wrapping overflow, this is fine. */
6135 /* If widening the type changes the signedness, then we can't perform
6136 this optimization as that changes the result. */
6140 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6146 {
6153 }
6157 /* If the second operand is constant, this is a multiplication
6158 or floor division, by a power of two, so we can treat it that
6159 way unless the multiplier or divisor overflows. Signed
6160 left-shift overflow is implementation-defined rather than
6161 undefined in C90, so do not convert signed left shift into
6162 multiplication. */
6165 /* const_binop may not detect overflow correctly,
6166 so check for it explicitly here. */
6170 size_one_node,
6171 op1)))
6175 ctype,
6177 t1),
6182 /* See if we can eliminate the operation on both sides. If we can, we
6183 can return a new PLUS or MINUS. If we can't, the only remaining
6184 cases where we can do anything are if the second operand is a
6185 constant. */
6191 /* If not multiplication, we can only do this if both operands
6192 are divisible by c. */
6195 {
6200 }
6202 /* If this was a subtraction, negate OP1 and set it to be an addition.
6203 This simplifies the logic below. */
6205 {
6207 /* If OP1 was not easily negatable, the constant may be OP0. */
6209 {
6212 }
6213 }
6218 /* If either OP1 or C are negative, this optimization is not safe for
6219 some of the division and remainder types while for others we need
6220 to change the code. */
6222 {
6230 }
6232 /* If it's a multiply or a division/modulus operation of a multiple
6233 of our constant, do the operation and verify it doesn't overflow. */
6236 {
6239 /* We allow the constant to overflow with wrapping semantics. */
6243 }
6244 else
6247 /* If we have an unsigned type, we cannot widen the operation since it
6248 will change the result if the original computation overflowed. */
6252 /* If we were able to eliminate our operation from the first side,
6253 apply our operation to the second side and reform the PLUS. */
6257 /* The last case is if we are a multiply. In that case, we can
6258 apply the distributive law to commute the multiply and addition
6259 if the multiplication of the constants doesn't overflow
6260 and overflow is defined. With undefined overflow
6261 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6267 op1);
6272 /* We have a special case here if we are doing something like
6273 (C * 8) % 4 since we know that's zero. */
6276 /* If the multiplication can overflow we cannot optimize this. */
6280 {
6283 }
6285 /* ... fall through ... */
6289 /* If we can extract our operation from the LHS, do so and return a
6290 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6291 do something only if the second operand is a constant. */
6305 /* If these are the same operation types, we can associate them
6306 assuming no overflow. */
6308 {
6323 }
6325 /* If these operations "cancel" each other, we have the main
6326 optimizations of this pass, which occur when either constant is a
6327 multiple of the other, in which case we replace this with either an
6328 operation or CODE or TCODE.
6330 If we have an unsigned type, we cannot do this since it will change
6331 the result if the original computation overflowed. */
6338 {
6340 {
6347 }
6349 {
6356 }
6357 }
6362 }
6365 }
6366 \f
6367 /* Return a node which has the indicated constant VALUE (either 0 or
6368 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6369 and is of the indicated TYPE. */
6371 tree
6373 {
6382 else
6384 }
6387 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6388 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6389 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6390 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6391 COND is the first argument to CODE; otherwise (as in the example
6392 given here), it is the second argument. TYPE is the type of the
6393 original expression. Return NULL_TREE if no simplification is
6394 possible. */
6396 static tree
6401 {
6411 {
6415 /* If this operand throws an expression, then it does not make
6416 sense to try to perform a logical or arithmetic operation
6417 involving it. */
6422 }
6425 {
6430 }
6431 else
6432 /* Detect the case of mixing vector and scalar types - bail out. */
6438 /* This transformation is only worthwhile if we don't have to wrap ARG
6439 in a SAVE_EXPR and the operation can be simplified without recursing
6440 on at least one of the branches once its pushed inside the COND_EXPR. */
6449 {
6453 else
6455 }
6457 {
6461 else
6463 }
6465 /* Check that we have simplified at least one of the branches. */
6470 }
6472 \f
6473 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6475 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6476 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6477 ADDEND is the same as X.
6479 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6480 and finite. The problematic cases are when X is zero, and its mode
6481 has signed zeros. In the case of rounding towards -infinity,
6482 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6483 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6485 bool
6487 {
6491 /* Don't allow the fold with -fsignaling-nans. */
6495 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6499 /* In a vector or complex, we would need to check the sign of all zeros. */
6503 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6507 /* The mode has signed zeros, and we have to honor their sign.
6508 In this situation, there is only one case we can return true for.
6509 X - 0 is the same as X unless rounding towards -infinity is
6510 supported. */
6512 }
6514 /* Subroutine of fold() that optimizes comparisons of a division by
6515 a nonzero integer constant against an integer constant, i.e.
6516 X/C1 op C2.
6518 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6519 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6520 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6522 The function returns the constant folded tree if a simplification
6523 can be made, and NULL_TREE otherwise. */
6525 static tree
6528 {
6536 /* We have to do this the hard way to detect unsigned overflow.
6537 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6543 {
6548 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6552 }
6554 {
6558 {
6577 }
6578 }
6579 else
6580 {
6581 /* A negative divisor reverses the relational operators. */
6587 {
6606 }
6607 }
6610 {
6631 {
6634 }
6639 {
6642 }
6647 {
6650 }
6655 {
6658 }
6663 }
6666 }
6669 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6670 equality/inequality test, then return a simplified form of the test
6671 using a sign testing. Otherwise return NULL. TYPE is the desired
6672 result type. */
6674 static tree
6677 tree result_type)
6678 {
6679 /* If this is testing a single bit, we can optimize the test. */
6683 {
6684 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6685 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6689 /* This is only a win if casting to a signed type is cheap,
6690 i.e. when arg00's type is not a partial mode. */
6693 {
6696 result_type,
6699 }
6700 }
6703 }
6705 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6706 equality/inequality test, then return a simplified form of
6707 the test using shifts and logical operations. Otherwise return
6708 NULL. TYPE is the desired result type. */
6710 tree
6713 {
6714 /* If this is testing a single bit, we can optimize the test. */
6718 {
6727 /* First, see if we can fold the single bit test into a sign-bit
6728 test. */
6730 result_type);
6734 /* Otherwise we have (A & C) != 0 where C is a single bit,
6735 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6736 Similarly for (A & C) == 0. */
6738 /* If INNER is a right shift of a constant and it plus BITNUM does
6739 not overflow, adjust BITNUM and INNER. */
6745 {
6748 }
6750 /* If we are going to be able to omit the AND below, we must do our
6751 operations as unsigned. If we must use the AND, we have a choice.
6752 Normally unsigned is faster, but for some machines signed is. */
6770 /* Put the AND last so it can combine with more things. */
6773 /* Make sure to return the proper type. */
6777 }
6779 }
6781 /* Check whether we are allowed to reorder operands arg0 and arg1,
6782 such that the evaluation of arg1 occurs before arg0. */
6784 static bool
6786 {
6793 }
6795 /* Test whether it is preferable two swap two operands, ARG0 and
6796 ARG1, for example because ARG0 is an integer constant and ARG1
6797 isn't. If REORDER is true, only recommend swapping if we can
6798 evaluate the operands in reverse order. */
6800 bool
6802 {
6820 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6821 for commutative and comparison operators. Ensuring a canonical
6822 form allows the optimizers to find additional redundancies without
6823 having to explicitly check for both orderings. */
6829 /* Put SSA_NAMEs last. */
6835 /* Put variables last. */
6842 }
6845 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6846 means A >= Y && A != MAX, but in this case we know that
6847 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6849 static tree
6851 {
6858 else
6867 {
6870 }
6872 {
6875 }
6876 else
6883 {
6884 /* Convert the pointer types into integer before taking the difference. */
6888 }
6889 else
6896 }
6898 /* Fold a sum or difference of at least one multiplication.
6899 Returns the folded tree or NULL if no simplification could be made. */
6901 static tree
6904 {
6908 /* (A * C) +- (B * C) -> (A+-B) * C.
6909 (A * C) +- A -> A * (C+-1).
6910 We are most concerned about the case where C is a constant,
6911 but other combinations show up during loop reduction. Since
6912 it is not difficult, try all four possibilities. */
6915 {
6918 }
6920 {
6923 }
6924 else
6925 {
6926 /* We cannot generate constant 1 for fract. */
6931 }
6933 {
6936 }
6938 {
6940 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6941 the purpose of this canonicalization. */
6945 {
6948 }
6949 else
6951 }
6952 else
6953 {
6954 /* We cannot generate constant 1 for fract. */
6959 }
6971 /* No identical multiplicands; see if we can find a common
6972 power-of-two factor in non-power-of-two multiplies. This
6973 can help in multi-dimensional array access. */
6976 {
6979 tree maybe_same;
6983 /* Move min of absolute values to int11. */
6985 {
6990 }
6991 else
6995 /* The remainder should not be a constant, otherwise we
6996 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6997 increased the number of multiplications necessary. */
6999 {
7007 }
7008 }
7018 }
7020 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7021 specified by EXPR into the buffer PTR of length LEN bytes.
7022 Return the number of bytes placed in the buffer, or zero
7023 upon failure. */
7025 static int
7027 {
7041 {
7043 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7044 number of bytes. */
7048 {
7055 else
7057 }
7058 else
7063 }
7065 }
7068 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7069 specified by EXPR into the buffer PTR of length LEN bytes.
7070 Return the number of bytes placed in the buffer, or zero
7071 upon failure. */
7073 static int
7075 {
7079 FIXED_VALUE_TYPE value;
7095 }
7098 /* Subroutine of native_encode_expr. Encode the REAL_CST
7099 specified by EXPR into the buffer PTR of length LEN bytes.
7100 Return the number of bytes placed in the buffer, or zero
7101 upon failure. */
7103 static int
7105 {
7111 /* There are always 32 bits in each long, no matter the size of
7112 the hosts long. We handle floating point representations with
7113 up to 192 bits. */
7127 {
7132 {
7139 else
7141 }
7142 else
7148 }
7150 }
7152 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7153 specified by EXPR into the buffer PTR of length LEN bytes.
7154 Return the number of bytes placed in the buffer, or zero
7155 upon failure. */
7157 static int
7159 {
7161 tree part;
7176 }
7179 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7180 specified by EXPR into the buffer PTR of length LEN bytes.
7181 Return the number of bytes placed in the buffer, or zero
7182 upon failure. */
7184 static int
7186 {
7196 {
7198 {
7201 }
7212 }
7214 }
7217 /* Subroutine of native_encode_expr. Encode the STRING_CST
7218 specified by EXPR into the buffer PTR of length LEN bytes.
7219 Return the number of bytes placed in the buffer, or zero
7220 upon failure. */
7222 static int
7224 {
7226 HOST_WIDE_INT total_bytes;
7240 {
7243 {
7246 }
7249 }
7250 else
7253 }
7256 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7257 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7258 buffer PTR of length LEN bytes. If OFF is not -1 then start
7259 the encoding at byte offset OFF and encode at most LEN bytes.
7260 Return the number of bytes placed in the buffer, or zero upon failure. */
7262 int
7264 {
7265 /* We don't support starting at negative offset and -1 is special. */
7270 {
7291 }
7292 }
7295 /* Subroutine of native_interpret_expr. Interpret the contents of
7296 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7297 If the buffer cannot be interpreted, return NULL_TREE. */
7299 static tree
7301 {
7311 }
7314 /* Subroutine of native_interpret_expr. Interpret the contents of
7315 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7316 If the buffer cannot be interpreted, return NULL_TREE. */
7318 static tree
7320 {
7322 double_int result;
7323 FIXED_VALUE_TYPE fixed_value;
7333 }
7336 /* Subroutine of native_interpret_expr. Interpret the contents of
7337 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7338 If the buffer cannot be interpreted, return NULL_TREE. */
7340 static tree
7342 {
7346 /* There are always 32 bits in each long, no matter the size of
7347 the hosts long. We handle floating point representations with
7348 up to 192 bits. */
7349 REAL_VALUE_TYPE r;
7360 {
7361 /* Both OFFSET and BYTE index within a long;
7362 bitpos indexes the whole float. */
7365 {
7372 else
7374 }
7375 else
7376 {
7379 {
7380 /* Reverse bytes within each long, or within the entire float
7381 if it's smaller than a long (for HFmode). */
7384 }
7385 }
7389 }
7393 }
7396 /* Subroutine of native_interpret_expr. Interpret the contents of
7397 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7398 If the buffer cannot be interpreted, return NULL_TREE. */
7400 static tree
7402 {
7417 }
7420 /* Subroutine of native_interpret_expr. Interpret the contents of
7421 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7422 If the buffer cannot be interpreted, return NULL_TREE. */
7424 static tree
7426 {
7439 {
7444 }
7446 }
7449 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7450 the buffer PTR of length LEN as a constant of type TYPE. For
7451 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7452 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7453 return NULL_TREE. */
7455 tree
7457 {
7459 {
7481 }
7482 }
7484 /* Returns true if we can interpret the contents of a native encoding
7485 as TYPE. */
7487 static bool
7489 {
7491 {
7504 }
7505 }
7507 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7508 TYPE at compile-time. If we're unable to perform the conversion
7509 return NULL_TREE. */
7511 static tree
7513 {
7514 /* We support up to 512-bit values (for V8DFmode). */
7518 /* Check that the host and target are sane. */
7527 }
7529 /* Build an expression for the address of T. Folds away INDIRECT_REF
7530 to avoid confusing the gimplify process. */
7532 tree
7534 {
7535 /* The size of the object is not relevant when talking about its address. */
7540 {
7545 }
7555 {
7560 }
7561 else
7565 }
7567 /* Build an expression for the address of T. */
7569 tree
7571 {
7575 }
7577 /* Fold a unary expression of code CODE and type TYPE with operand
7578 OP0. Return the folded expression if folding is successful.
7579 Otherwise, return NULL_TREE. */
7581 tree
7583 {
7584 tree tem;
7585 tree arg0;
7593 {
7596 {
7597 /* Don't use STRIP_NOPS, because signedness of argument type
7598 matters. */
7600 }
7601 else
7602 {
7603 /* Strip any conversions that don't change the mode. This
7604 is safe for every expression, except for a comparison
7605 expression because its signedness is derived from its
7606 operands.
7608 Note that this is done as an internal manipulation within
7609 the constant folder, in order to find the simplest
7610 representation of the arguments so that their form can be
7611 studied. In any cases, the appropriate type conversions
7612 should be put back in the tree that will get out of the
7613 constant folder. */
7615 }
7618 {
7621 {
7625 }
7626 }
7627 }
7634 {
7641 {
7655 /* If this was a conversion, and all we did was to move into
7656 inside the COND_EXPR, bring it back out. But leave it if
7657 it is a conversion from integer to integer and the
7658 result precision is no wider than a word since such a
7659 conversion is cheap and may be optimized away by combine,
7660 while it couldn't if it were outside the COND_EXPR. Then return
7661 so we don't get into an infinite recursion loop taking the
7662 conversion out and then back in. */
7674 && (INTEGRAL_TYPE_P
7687 }
7688 }
7691 {
7697 CASE_CONVERT:
7701 {
7702 /* If we have (type) (a CMP b) and type is an integral type, return
7703 new expression involving the new type. Canonicalize
7704 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7705 non-integral type.
7706 Do not fold the result as that would not simplify further, also
7707 folding again results in recursions. */
7717 }
7719 /* Handle (T *)&A.B.C for A being of type T and B and C
7720 living at offset zero. This occurs frequently in
7721 C++ upcasting and then accessing the base. */
7725 {
7727 tree offset;
7728 machine_mode mode;
7730 tree base
7734 /* If the reference was to a (constant) zero offset, we can use
7735 the address of the base if it has the same base type
7736 as the result type and the pointer type is unqualified. */
7743 }
7747 /* Detect assigning a bitfield. */
7749 && DECL_BIT_FIELD
7751 {
7752 /* Don't leave an assignment inside a conversion
7753 unless assigning a bitfield. */
7755 /* First do the assignment, then return converted constant. */
7760 }
7762 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7763 constants (if x has signed type, the sign bit cannot be set
7764 in c). This folds extension into the BIT_AND_EXPR.
7765 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7766 very likely don't have maximal range for their precision and this
7767 transformation effectively doesn't preserve non-maximal ranges. */
7771 {
7782 <= HOST_BITS_PER_WIDE_INT
7784 {
7788 cst &= HOST_WIDE_INT_M1U
7792 && !flag_syntax_only
7795 {
7799 }
7800 }
7802 {
7807 }
7808 }
7810 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7811 cast (T1)X will fold away. We assume that this happens when X itself
7812 is a cast. */
7816 {
7820 return fold_build_pointer_plus_loc
7822 }
7824 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7825 of the same precision, and X is an integer type not narrower than
7826 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7832 {
7838 }
7840 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7841 type of X and Y (integer types only). */
7846 {
7847 /* Be careful not to introduce new overflows. */
7848 tree mult_type;
7851 else
7855 {
7862 }
7863 }
7869 {
7876 }
7887 /* Convert fabs((double)float) into (double)fabsf(float). */
7890 {
7896 targ0));
7897 }
7901 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7920 /* Note that the operand of this must be an int
7921 and its values must be 0 or 1.
7922 ("true" is a fixed value perhaps depending on the language,
7923 but we don't handle values other than 1 correctly yet.) */
7930 /* Fold *&X to X if X is an lvalue. */
7932 {
7939 }
7945 }
7948 /* If the operation was a conversion do _not_ mark a resulting constant
7949 with TREE_OVERFLOW if the original constant was not. These conversions
7950 have implementation defined behavior and retaining the TREE_OVERFLOW
7951 flag here would confuse later passes such as VRP. */
7952 tree
7955 {
7964 }
7966 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7967 operands OP0 and OP1. LOC is the location of the resulting expression.
7968 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7969 Return the folded expression if folding is successful. Otherwise,
7970 return NULL_TREE. */
7971 static tree
7974 {
7975 tree tem;
7977 /* We only do these simplifications if we are optimizing. */
7981 /* Check for things like (A || B) && (A || C). We can convert this
7982 to A || (B && C). Note that either operator can be any of the four
7983 truth and/or operations and the transformation will still be
7984 valid. Also note that we only care about order for the
7985 ANDIF and ORIF operators. If B contains side effects, this
7986 might change the truth-value of A. */
7993 {
8013 /* This case if tricky because we must either have commutative
8014 operators or else A10 must not have side-effects. */
8020 a01);
8021 }
8023 /* See if we can build a range comparison. */
8029 {
8033 }
8037 {
8041 }
8043 /* Check for the possibility of merging component references. If our
8044 lhs is another similar operation, try to merge its rhs with our
8045 rhs. Then try to merge our lhs and rhs. */
8059 {
8066 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8067 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8068 We don't want to pack more than two leafs to a non-IF AND/OR
8069 expression.
8070 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8071 equal to IF-CODE, then we don't want to add right-hand operand.
8072 If the inner right-hand side of left-hand operand has
8073 side-effects, or isn't simple, then we can't add to it,
8074 as otherwise we might destroy if-sequence. */
8077 /* Needed for sequence points to handle trappings, and
8078 side-effects. */
8080 {
8082 arg1);
8084 tem);
8085 }
8086 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8087 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8090 /* Needed for sequence points to handle trappings, and
8091 side-effects. */
8093 {
8098 }
8099 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8100 into (A OR B).
8101 For sequence point consistancy, we need to check for trapping,
8102 and side-effects. */
8106 }
8109 }
8111 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8112 by changing CODE to reduce the magnitude of constants involved in
8113 ARG0 of the comparison.
8114 Returns a canonicalized comparison tree if a simplification was
8115 possible, otherwise returns NULL_TREE.
8116 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8117 valid if signed overflow is undefined. */
8119 static tree
8123 {
8128 /* Match A +- CST code arg1. We can change this only if overflow
8129 is undefined. */
8132 /* In principle pointers also have undefined overflow behavior,
8133 but that causes problems elsewhere. */
8140 /* Identify the constant in arg0 and its sign. */
8144 /* Overflowed constants and zero will cause problems. */
8149 /* See if we can reduce the magnitude of the constant in
8150 arg0 by changing the comparison code. */
8151 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8155 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8159 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8163 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8167 else
8171 /* Now build the constant reduced in magnitude. But not if that
8172 would produce one outside of its types range. */
8188 }
8190 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8191 overflow further. Try to decrease the magnitude of constants involved
8192 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8193 and put sole constants at the second argument position.
8194 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8196 static tree
8199 {
8200 tree t;
8205 /* Try canonicalization by simplifying arg0. */
8210 {
8214 }
8216 /* Try canonicalization by simplifying arg1 using the swapped
8217 comparison. */
8225 }
8227 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8228 space. This is used to avoid issuing overflow warnings for
8229 expressions like &p->x which can not wrap. */
8231 static bool
8233 {
8240 wide_int wi_offset;
8246 else
8262 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8263 array. */
8265 {
8266 HOST_WIDE_INT base_size;
8271 }
8274 }
8276 /* Return a positive integer when the symbol DECL is known to have
8277 a nonzero address, zero when it's known not to (e.g., it's a weak
8278 symbol), and a negative integer when the symbol is not yet in the
8279 symbol table and so whether or not its address is zero is unknown. */
8280 static int
8282 {
8288 }
8290 /* Subroutine of fold_binary. This routine performs all of the
8291 transformations that are common to the equality/inequality
8292 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8293 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8294 fold_binary should call fold_binary. Fold a comparison with
8295 tree code CODE and type TYPE with operands OP0 and OP1. Return
8296 the folded comparison or NULL_TREE. */
8298 static tree
8301 {
8311 /* For comparisons of pointers we can decompose it to a compile time
8312 comparison of the base objects and the offsets into the object.
8313 This requires at least one operand being an ADDR_EXPR or a
8314 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8320 {
8323 machine_mode mode;
8327 /* Get base and offset for the access. Strip ADDR_EXPR for
8328 get_inner_reference, but put it back by stripping INDIRECT_REF
8329 off the base object if possible. indirect_baseN will be true
8330 if baseN is not an address but refers to the object itself. */
8333 {
8334 base0
8340 else
8342 }
8344 {
8348 {
8349 base0
8355 else
8357 }
8360 else
8364 {
8370 {
8373 }
8374 }
8375 }
8379 {
8380 base1
8386 else
8388 }
8390 {
8394 {
8395 base1
8401 else
8403 }
8406 else
8410 {
8416 {
8419 }
8420 }
8421 }
8423 /* If we have equivalent bases we might be able to simplify. */
8427 {
8428 /* We can fold this expression to a constant if the non-constant
8429 offset parts are equal. */
8433 && (equality_code
8434 || (indirect_base0
8438 {
8444 "occur when comparing P +- C1 with "
8446 WARN_STRICT_OVERFLOW_CONDITIONAL);
8449 {
8463 }
8464 }
8465 /* We can simplify the comparison to a comparison of the variable
8466 offset parts if the constant offset parts are equal.
8467 Be careful to use signed sizetype here because otherwise we
8468 mess with array offsets in the wrong way. This is possible
8469 because pointer arithmetic is restricted to retain within an
8470 object and overflow on pointer differences is undefined as of
8471 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8473 && (equality_code
8474 || (indirect_base0
8477 {
8478 /* By converting to signed sizetype we cover middle-end pointer
8479 arithmetic which operates on unsigned pointer types of size
8480 type size and ARRAY_REF offsets which are properly sign or
8481 zero extended from their type in case it is narrower than
8482 sizetype. */
8485 else
8489 else
8496 "occur when comparing P +- C1 with "
8498 WARN_STRICT_OVERFLOW_COMPARISON);
8501 }
8502 }
8503 /* For equal offsets we can simplify to a comparison of the
8504 base addresses. */
8506 && (indirect_base0
8508 && (indirect_base1
8513 {
8519 }
8520 /* Comparison between an ordinary (non-weak) symbol and a null
8521 pointer can be eliminated since such symbols must have a non
8522 null address. In C, relational expressions between pointers
8523 to objects and null pointers are undefined. The results
8524 below follow the C++ rules with the additional property that
8525 every object pointer compares greater than a null pointer.
8526 */
8529 /* Avoid folding references to struct members at offset 0 to
8530 prevent tests like '&ptr->firstmember == 0' from getting
8531 eliminated. When ptr is null, although the -> expression
8532 is strictly speaking invalid, GCC retains it as a matter
8533 of QoI. See PR c/44555. */
8535 /* The caller guarantees that when one of the arguments is
8536 constant (i.e., null in this case) it is second. */
8538 {
8540 {
8551 }
8552 }
8553 }
8555 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8556 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8557 the resulting offset is smaller in absolute value than the
8558 original one and has the same sign. */
8567 {
8572 tree cst;
8574 "occur when combining constants around "
8577 /* Put the constant on the side where it doesn't overflow and is
8578 of lower absolute value and of same sign than before. */
8585 {
8588 variable1,
8592 }
8600 {
8606 variable2);
8607 }
8608 }
8614 /* If we are comparing an expression that just has comparisons
8615 of two integer values, arithmetic expressions of those comparisons,
8616 and constants, we can simplify it. There are only three cases
8617 to check: the two values can either be equal, the first can be
8618 greater, or the second can be greater. Fold the expression for
8619 those three values. Since each value must be 0 or 1, we have
8620 eight possibilities, each of which corresponds to the constant 0
8621 or 1 or one of the six possible comparisons.
8623 This handles common cases like (a > b) == 0 but also handles
8624 expressions like ((x > y) - (y > x)) > 0, which supposedly
8625 occur in macroized code. */
8628 {
8633 /* Don't handle degenerate cases here; they should already
8634 have been handled anyway. */
8643 {
8647 /* We can't just pass T to eval_subst in case cval1 or cval2
8648 was the same as ARG1. */
8650 tree high_result
8654 arg1);
8655 tree equal_result
8659 arg1);
8660 tree low_result
8664 arg1);
8666 /* All three of these results should be 0 or 1. Confirm they are.
8667 Then use those values to select the proper code to use. */
8672 {
8673 /* Make a 3-bit mask with the high-order bit being the
8674 value for `>', the next for '=', and the low for '<'. */
8678 {
8680 /* Always false. */
8701 /* Always true. */
8703 }
8706 {
8710 }
8712 }
8713 }
8714 }
8716 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8717 into a single range test. */
8725 {
8729 }
8732 }
8735 /* Subroutine of fold_binary. Optimize complex multiplications of the
8736 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8737 argument EXPR represents the expression "z" of type TYPE. */
8739 static tree
8741 {
8746 {
8749 }
8751 {
8754 }
8755 else
8756 {
8760 }
8769 }
8772 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8773 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8775 static bool
8777 {
8781 {
8784 }
8786 {
8792 else
8794 }
8795 else
8801 }
8803 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8804 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8805 NULL_TREE otherwise. */
8807 static tree
8809 {
8826 {
8830 }
8833 {
8839 }
8840 else
8842 }
8844 /* Try to fold a pointer difference of type TYPE two address expressions of
8845 array references AREF0 and AREF1 using location LOC. Return a
8846 simplified expression for the difference or NULL_TREE. */
8848 static tree
8851 {
8856 /* If the bases are array references as well, recurse. If the bases
8857 are pointer indirections compute the difference of the pointers.
8858 If the bases are equal, we are set. */
8861 && (base_offset
8865 && (base_offset
8871 {
8877 base_offset,
8880 }
8882 }
8884 /* If the real or vector real constant CST of type TYPE has an exact
8885 inverse, return it, else return NULL. */
8887 tree
8889 {
8890 REAL_VALUE_TYPE r;
8892 machine_mode mode;
8896 {
8912 {
8917 }
8923 }
8924 }
8926 /* Mask out the tz least significant bits of X of type TYPE where
8927 tz is the number of trailing zeroes in Y. */
8928 static wide_int
8930 {
8935 }
8937 /* Return true when T is an address and is known to be nonzero.
8938 For floating point we further ensure that T is not denormal.
8939 Similar logic is present in nonzero_address in rtlanal.h.
8941 If the return value is based on the assumption that signed overflow
8942 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8943 change *STRICT_OVERFLOW_P. */
8945 static bool
8947 {
8951 /* Doing something useful for floating point would need more work. */
8957 {
8960 strict_overflow_p);
8966 strict_overflow_p);
8974 }
8977 {
8980 strict_overflow_p);
8988 strict_overflow_p);
9003 strict_overflow_p);
9007 strict_overflow_p);
9010 {
9022 }
9026 }
9028 }
9030 /* Return true when T is an address and is known to be nonzero.
9031 Handle warnings about undefined signed overflow. */
9033 static bool
9035 {
9042 "determining that expression is always "
9044 WARN_STRICT_OVERFLOW_MISC);
9046 }
9048 /* Return true if T is known not to be equal to an integer W. */
9050 bool
9052 {
9054 value_range_type rtype;
9056 {
9065 {
9070 }
9075 /* If T has some known zero bits and W has any of those bits set,
9076 then T is known not to be equal to W. */
9084 }
9085 }
9087 /* Fold a binary expression of code CODE and type TYPE with operands
9088 OP0 and OP1. LOC is the location of the resulting expression.
9089 Return the folded expression if folding is successful. Otherwise,
9090 return NULL_TREE. */
9092 tree
9095 {
9110 /* Strip any conversions that don't change the mode. This is
9111 safe for every expression, except for a comparison expression
9112 because its signedness is derived from its operands. So, in
9113 the latter case, only strip conversions that don't change the
9114 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9115 preserved.
9117 Note that this is done as an internal manipulation within the
9118 constant folder, in order to find the simplest representation
9119 of the arguments so that their form can be studied. In any
9120 cases, the appropriate type conversions should be put back in
9121 the tree that will get out of the constant folder. */
9124 {
9127 }
9128 else
9129 {
9132 }
9134 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9135 constant but we can't do arithmetic on them. */
9137 {
9140 {
9144 }
9145 }
9147 /* If this is a commutative operation, and ARG0 is a constant, move it
9148 to ARG1 to reduce the number of tests below. */
9153 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9154 to ARG1 to reduce the number of tests below. */
9163 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9165 First check for cases where an arithmetic operation is applied to a
9166 compound, conditional, or comparison operation. Push the arithmetic
9167 operation inside the compound or conditional to see if any folding
9168 can then be done. Convert comparison to conditional for this purpose.
9169 The also optimizes non-constant cases that used to be done in
9170 expand_expr.
9172 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9173 one of the operands is a comparison and the other is a comparison, a
9174 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9175 code below would make the expression more complex. Change it to a
9176 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9177 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9190 {
9194 boolean_type_node,
9202 }
9206 {
9208 {
9213 tem);
9214 }
9217 {
9222 tem);
9223 }
9228 {
9234 }
9239 {
9245 }
9246 }
9249 {
9251 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9254 {
9260 }
9262 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9265 {
9266 tree base;
9267 HOST_WIDE_INT coffset;
9276 }
9281 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9287 arg1),
9289 arg0)));
9295 {
9296 /* X + (X / CST) * -CST is X % CST. */
9301 {
9310 cst0));
9311 }
9312 }
9314 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9315 one. Make sure the type is not saturating and has the signedness of
9316 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9317 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9324 {
9328 }
9331 {
9332 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9333 (plus (plus (mult) (mult)) (foo)) so that we can
9334 take advantage of the factoring cases below. */
9343 {
9349 else
9362 parg0),
9364 marg)),
9368 return
9374 parg1)));
9375 }
9376 }
9377 else
9378 {
9379 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9380 to __complex__ ( x, y ). This is not the same for SNaNs or
9381 if signed zeros are involved. */
9385 {
9392 {
9396 {
9402 }
9404 {
9410 }
9411 }
9412 }
9420 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9421 We associate floats only if the user has specified
9422 -fassociative-math. */
9426 {
9431 {
9432 tree tree0;
9435 }
9436 }
9437 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9438 We associate floats only if the user has specified
9439 -fassociative-math. */
9443 {
9448 {
9449 tree tree0;
9452 }
9453 }
9454 }
9456 bit_rotate:
9457 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9458 is a rotate of A by C1 bits. */
9459 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9460 is a rotate of A by B bits. */
9461 {
9463 tree rtype;
9472 /* Only create rotates in complete modes. Other cases are not
9473 expanded properly. */
9476 {
9490 {
9494 code0 == LSHIFT_EXPR
9498 }
9500 {
9508 element_precision
9512 return
9515 ? LROTATE_EXPR
9520 }
9522 {
9530 element_precision
9534 return fold_convert_loc
9537 ? LROTATE_EXPR
9541 }
9542 }
9543 }
9545 associate:
9546 /* In most languages, can't associate operations on floats through
9547 parentheses. Rather than remember where the parentheses were, we
9548 don't associate floats at all, unless the user has specified
9549 -fassociative-math.
9550 And, we need to make sure type is not saturating. */
9554 {
9560 /* Split both trees into variables, constants, and literals. Then
9561 associate each group together, the constants with literals,
9562 then the result with variables. This increases the chances of
9563 literals being recombined later and of generating relocatable
9564 expressions for the sum of a constant and literal. */
9570 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9574 /* With undefined overflow prefer doing association in a type
9575 which wraps on overflow, if that is one of the operand types. */
9578 {
9586 }
9588 /* With undefined overflow we can only associate constants with one
9589 variable, and constants whose association doesn't overflow. */
9592 {
9594 {
9600 {
9603 }
9610 {
9613 }
9619 /* The only case we can still associate with two variables
9620 is if they cancel out. */
9624 }
9625 }
9627 /* Only do something if we found more than two objects. Otherwise,
9628 nothing has changed and we risk infinite recursion. */
9634 {
9646 /* Preserve the MINUS_EXPR if the negative part of the literal is
9647 greater than the positive part. Otherwise, the multiplicative
9648 folding code (i.e extract_muldiv) may be fooled in case
9649 unsigned constants are subtracted, like in the following
9650 example: ((X*2 + 4) - 8U)/2. */
9652 {
9656 {
9660 }
9661 else
9662 {
9666 }
9667 }
9669 /* Don't introduce overflows through reassociation. */
9676 {
9678 return
9682 else
9683 {
9686 return
9690 }
9691 }
9694 return
9697 }
9698 }
9703 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9712 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9713 __complex__ ( x, -y ). This is not the same for SNaNs or if
9714 signed zeros are involved. */
9718 {
9725 {
9729 {
9731 arg1r ? arg1r
9736 }
9738 {
9742 arg1i ? arg1i
9745 }
9746 }
9747 }
9749 /* A - B -> A + (-B) if B is easily negatable. */
9753 /* Avoid this transformation if B is a positive REAL_CST. */
9761 /* Fold &a[i] - &a[j] to i-j. */
9766 {
9772 }
9775 && flag_unsafe_math_optimizations
9781 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9782 one. Make sure the type is not saturating and has the signedness of
9783 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9784 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9791 {
9795 }
9801 {
9802 /* Transform x * -C into -x * C if x is easily negatable. */
9816 {
9819 "occur when simplifying "
9821 WARN_STRICT_OVERFLOW_MISC);
9823 }
9825 /* Optimize z * conj(z) for integer complex numbers. */
9832 }
9833 else
9834 {
9835 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9836 This is not the same for NaNs or if signed zeros are
9837 involved. */
9843 {
9846 return
9852 return
9857 }
9859 /* Optimize z * conj(z) for floating point complex numbers.
9860 Guarded by flag_unsafe_math_optimizations as non-finite
9861 imaginary components don't produce scalar results. */
9870 }
9874 /* Canonicalize (X & C1) | C2. */
9878 {
9883 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9891 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9896 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9897 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9898 mode which allows further optimizations. */
9903 {
9907 {
9910 }
9911 }
9918 c3)),
9919 arg1);
9920 }
9922 /* See if this can be simplified into a rotate first. If that
9923 is unsuccessful continue in the association code. */
9927 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9935 /* See if this can be simplified into a rotate first. If that
9936 is unsuccessful continue in the association code. */
9940 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9945 {
9946 tree tem2;
9953 }
9954 /* Fold ~X & 1 as (X & 1) == 0. */
9958 {
9959 tree tem2;
9966 }
9967 /* Fold !X & 1 as X == 0. */
9970 {
9974 }
9976 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
9977 multiple of 1 << CST. */
9979 {
9986 }
9988 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
9989 bits from CST2. */
9993 {
10001 {
10002 /* Avoid the transform if arg1 is a mask of some
10003 mode which allows further optimizations. */
10010 }
10011 }
10013 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10014 ((A & N) + B) & M -> (A + B) & M
10015 Similarly if (N & M) == 0,
10016 ((A | N) + B) & M -> (A + B) & M
10017 and for - instead of + (or unary - instead of +)
10018 and/or ^ instead of |.
10019 If B is constant and (B & M) == 0, fold into A & M. */
10021 {
10030 {
10033 wide_int cst0;
10035 /* Now we know that arg0 is (C + D) or (C - D) or
10036 -C and arg1 (M) is == (1LL << cst) - 1.
10037 Store C into PMOP[0] and D into PMOP[1]. */
10041 {
10044 }
10051 {
10061 {
10064 }
10067 /* If C or D is of the form (A & N) where
10068 (N & M) == M, or of the form (A | N) or
10069 (A ^ N) where (N & M) == 0, replace it with A. */
10073 /* If C or D is a N where (N & M) == 0, it can be
10074 omitted (assumed 0). */
10082 }
10084 /* Only build anything new if we optimized one or both arguments
10085 above. */
10089 {
10092 {
10093 /* Perform the operations in a type that has defined
10094 overflow behavior. */
10100 }
10105 {
10113 else
10115 }
10118 else
10121 /* TEM is now the new binary +, - or unary - replacement. */
10125 }
10126 }
10127 }
10129 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10132 {
10137 return
10139 }
10144 /* Don't touch a floating-point divide by zero unless the mode
10145 of the constant can represent infinity. */
10151 /* (-A) / (-B) -> A / B */
10163 /* Fall through */
10166 /* Simplify A / (B << N) where A and B are positive and B is
10167 a power of 2, to A >> (N + log2(B)). */
10172 {
10175 {
10183 WARN_STRICT_OVERFLOW_MISC);
10189 }
10190 }
10192 /* Fall through */
10200 /* Convert -A / -B to A / B when the type is signed and overflow is
10201 undefined. */
10205 {
10208 "when distributing negation across "
10210 WARN_STRICT_OVERFLOW_MISC);
10215 }
10219 {
10222 "when distributing negation across "
10224 WARN_STRICT_OVERFLOW_MISC);
10229 }
10231 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10232 operation, EXACT_DIV_EXPR.
10234 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10235 At one time others generated faster code, it's not clear if they do
10236 after the last round to changes to the DIV code in expmed.c. */
10247 {
10251 WARN_STRICT_OVERFLOW_MISC);
10253 }
10265 {
10269 WARN_STRICT_OVERFLOW_MISC);
10271 }
10279 /* Since negative shift count is not well-defined,
10280 don't try to compute it in the compiler. */
10286 /* If we have a rotate of a bit operation with the rotate count and
10287 the second operand of the bit operation both constant,
10288 permute the two operations. */
10294 {
10302 }
10304 /* Two consecutive rotates adding up to the some integer
10305 multiple of the precision of the type can be ignored. */
10320 /* Note that the operands of this must be ints
10321 and their values must be 0 or 1.
10322 ("true" is a fixed value perhaps depending on the language.) */
10323 /* If first arg is constant zero, return it. */
10327 /* If either arg is constant true, drop it. */
10331 /* Preserve sequence points. */
10334 /* If second arg is constant zero, result is zero, but first arg
10335 must be evaluated. */
10338 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10339 case will be handled here. */
10343 /* !X && X is always false. */
10347 /* X && !X is always false. */
10352 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10353 means A >= Y && A != MAX, but in this case we know that
10354 A < X <= MAX. */
10358 {
10366 }
10375 /* Note that the operands of this must be ints
10376 and their values must be 0 or true.
10377 ("true" is a fixed value perhaps depending on the language.) */
10378 /* If first arg is constant true, return it. */
10382 /* If either arg is constant zero, drop it. */
10386 /* Preserve sequence points. */
10389 /* If second arg is constant true, result is true, but we must
10390 evaluate first arg. */
10393 /* Likewise for first arg, but note this only occurs here for
10394 TRUTH_OR_EXPR. */
10398 /* !X || X is always true. */
10402 /* X || !X is always true. */
10407 /* (X && !Y) || (!X && Y) is X ^ Y */
10410 {
10427 }
10436 /* If the second arg is constant zero, drop it. */
10439 /* If the second arg is constant true, this is a logical inversion. */
10441 {
10444 }
10445 /* Identical arguments cancel to zero. */
10449 /* !X ^ X is always true. */
10454 /* X ^ !X is always true. */
10470 /* bool_var != 1 becomes !bool_var. */
10477 /* bool_var == 0 becomes !bool_var. */
10484 /* !exp != 0 becomes !exp */
10489 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10498 {
10504 }
10506 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10515 {
10521 }
10523 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
10531 code == NE_EXPR
10535 /* Transform comparisons of the form X CMP C - X if C % 2 == 1. */
10543 code == NE_EXPR
10547 /* If this is an EQ or NE comparison with zero and ARG0 is
10548 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10549 two operations, but the latter can be done in one less insn
10550 on machines that have only two-operand insns or on which a
10551 constant cannot be the first operand. */
10554 {
10559 {
10566 arg1);
10567 }
10570 {
10577 arg1);
10578 }
10579 }
10581 /* If this is an NE or EQ comparison of zero against the result of a
10582 signed MOD operation whose second operand is a power of 2, make
10583 the MOD operation unsigned since it is simpler and equivalent. */
10591 {
10601 }
10603 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10604 C1 is a valid shift constant, and C2 is a power of two, i.e.
10605 a single bit. */
10609 == INTEGER_CST
10612 {
10617 /* Check for a valid shift count. */
10619 {
10623 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10624 can be rewritten as (X & (C2 << C1)) != 0. */
10626 {
10631 }
10632 /* Otherwise, for signed (arithmetic) shifts,
10633 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10634 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10638 /* Otherwise, of unsigned (logical) shifts,
10639 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10640 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10641 else
10645 arg000);
10646 }
10647 }
10649 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
10650 Similarly for NE_EXPR. */
10654 {
10658 tree dandnotc
10661 notc);
10665 }
10667 /* If this is a comparison of a field, we may be able to simplify it. */
10670 /* Handle the constant case even without -O
10671 to make sure the warnings are given. */
10673 {
10677 }
10679 /* Optimize comparisons of strlen vs zero to a compare of the
10680 first character of the string vs zero. To wit,
10681 strlen(ptr) == 0 => *ptr == 0
10682 strlen(ptr) != 0 => *ptr != 0
10683 Other cases should reduce to one of these two (or a constant)
10684 due to the return value of strlen being unsigned. */
10687 {
10695 {
10700 }
10701 }
10703 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10704 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10708 {
10713 {
10715 {
10718 }
10721 }
10722 }
10724 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10725 (X & C) == 0 when C is a single bit. */
10730 {
10737 arg1));
10738 }
10740 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10741 constant C is a power of two, i.e. a single bit. */
10748 {
10752 }
10754 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10755 when is C is a power of two, i.e. a single bit. */
10762 {
10768 }
10772 {
10775 }
10777 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10780 {
10793 arg01),
10802 arg01),
10811 arg00),
10820 arg00),
10822 }
10826 {
10833 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10834 operand_equal_p guarantees no side-effects so we don't need
10835 to use omit_one_operand on Z. */
10839 arg10));
10843 arg11));
10847 arg10));
10851 arg11));
10853 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10856 {
10862 }
10863 }
10865 /* Attempt to simplify equality/inequality comparisons of complex
10866 values. Only lower the comparison if the result is known or
10867 can be simplified to a single scalar comparison. */
10872 {
10877 {
10880 }
10881 else
10882 {
10885 }
10888 {
10891 }
10892 else
10893 {
10896 }
10900 {
10902 {
10907 }
10908 else
10909 {
10914 }
10915 }
10919 {
10921 {
10926 }
10927 else
10928 {
10933 }
10934 }
10935 }
10947 /* Transform comparisons of the form X +- C CMP X. */
10954 {
10961 else
10964 /* (X - c) > X becomes false. */
10968 {
10972 "occur when assuming that (X - c) > X "
10974 WARN_STRICT_OVERFLOW_ALL);
10976 }
10978 /* Likewise (X + c) < X becomes false. */
10982 {
10986 "occur when assuming that "
10988 WARN_STRICT_OVERFLOW_ALL);
10990 }
10992 /* Convert (X - c) <= X to true. */
10997 {
11001 "occur when assuming that "
11003 WARN_STRICT_OVERFLOW_ALL);
11005 }
11007 /* Convert (X + c) >= X to true. */
11012 {
11016 "occur when assuming that "
11018 WARN_STRICT_OVERFLOW_ALL);
11020 }
11023 {
11024 /* Convert X + c > X and X - c < X to true for integers. */
11028 {
11031 "not occur when assuming that "
11033 WARN_STRICT_OVERFLOW_ALL);
11035 }
11040 {
11043 "not occur when assuming that "
11045 WARN_STRICT_OVERFLOW_ALL);
11047 }
11049 /* Convert X + c <= X and X - c >= X to false for integers. */
11053 {
11056 "not occur when assuming that "
11058 WARN_STRICT_OVERFLOW_ALL);
11060 }
11065 {
11068 "not occur when assuming that "
11070 WARN_STRICT_OVERFLOW_ALL);
11072 }
11073 }
11074 }
11076 /* If we are comparing an ABS_EXPR with a constant, we can
11077 convert all the cases into explicit comparisons, but they may
11078 well not be faster than doing the ABS and one comparison.
11079 But ABS (X) <= C is a range comparison, which becomes a subtraction
11080 and a comparison, and is probably faster. */
11094 /* Convert ABS_EXPR<x> >= 0 to true. */
11101 {
11104 "when simplifying comparison of "
11106 WARN_STRICT_OVERFLOW_CONDITIONAL);
11109 arg0);
11110 }
11112 /* Convert ABS_EXPR<x> < 0 to false. */
11117 {
11120 "when simplifying comparison of "
11122 WARN_STRICT_OVERFLOW_CONDITIONAL);
11125 arg0);
11126 }
11128 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11129 and similarly for >= into !=. */
11139 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11140 otherwise Y might be >= # of bits in X's type and thus e.g.
11141 (unsigned char) (1 << Y) for Y 15 might be 0.
11142 If the cast is widening, then 1 << Y should have unsigned type,
11143 otherwise if Y is number of bits in the signed shift type minus 1,
11144 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11145 31 might be 0xffffffff80000000. */
11156 {
11162 }
11174 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11175 {
11187 }
11192 /* When pedantic, a compound expression can be neither an lvalue
11193 nor an integer constant expression. */
11196 /* Don't let (0, 0) be null pointer constant. */
11202 /* An ASSERT_EXPR should never be passed to fold_binary. */
11208 }
11210 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11211 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11212 of GOTO_EXPR. */
11214 static tree
11216 {
11218 {
11225 /* ... fall through ... */
11229 }
11230 }
11232 /* Return whether the sub-tree ST contains a label which is accessible from
11233 outside the sub-tree. */
11235 static bool
11237 {
11238 return
11240 }
11242 /* Fold a ternary expression of code CODE and type TYPE with operands
11243 OP0, OP1, and OP2. Return the folded expression if folding is
11244 successful. Otherwise, return NULL_TREE. */
11246 tree
11249 {
11250 tree tem;
11257 /* If this is a commutative operation, and OP0 is a constant, move it
11258 to OP1 to reduce the number of tests below. */
11267 /* Strip any conversions that don't change the mode. This is safe
11268 for every expression, except for a comparison expression because
11269 its signedness is derived from its operands. So, in the latter
11270 case, only strip conversions that don't change the signedness.
11272 Note that this is done as an internal manipulation within the
11273 constant folder, in order to find the simplest representation of
11274 the arguments so that their form can be studied. In any cases,
11275 the appropriate type conversions should be put back in the tree
11276 that will get out of the constant folder. */
11278 {
11281 }
11284 {
11287 }
11290 {
11293 }
11296 {
11300 {
11306 }
11311 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11312 so all simple results must be passed through pedantic_non_lvalue. */
11314 {
11317 /* Only optimize constant conditions when the selected branch
11318 has the same type as the COND_EXPR. This avoids optimizing
11319 away "c ? x : throw", where the throw has a void type.
11320 Avoid throwing away that operand which contains label. */
11327 }
11329 {
11334 {
11339 {
11347 }
11351 }
11352 }
11354 /* If we have A op B ? A : C, we may be able to convert this to a
11355 simpler expression, depending on the operation and the values
11356 of B and C. Signed zeros prevent all of these transformations,
11357 for reasons given above each one.
11359 Also try swapping the arguments and inverting the conditional. */
11364 {
11368 }
11372 op2,
11375 {
11379 {
11383 }
11384 }
11386 /* If the second operand is simpler than the third, swap them
11387 since that produces better jump optimization results. */
11390 {
11392 /* See if this can be inverted. If it can't, possibly because
11393 it was a floating-point inequality comparison, don't do
11394 anything. */
11398 }
11400 /* Convert A ? 1 : 0 to simply A. */
11405 /* If we try to convert OP0 to our type, the
11406 call to fold will try to move the conversion inside
11407 a COND, which will recurse. In that case, the COND_EXPR
11408 is probably the best choice, so leave it alone. */
11412 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11413 over COND_EXPR in cases such as floating point comparisons. */
11422 arg0)));
11424 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11429 {
11430 /* sign_bit_p looks through both zero and sign extensions,
11431 but for this optimization only sign extensions are
11432 usable. */
11435 {
11438 {
11441 }
11443 }
11444 /* sign_bit_p only checks ARG1 bits within A's precision.
11445 If <sign bit of A> has wider type than A, bits outside
11446 of A's precision in <sign bit of A> need to be checked.
11447 If they are all 0, this optimization needs to be done
11448 in unsigned A's type, if they are all 1 in signed A's type,
11449 otherwise this can't be done. */
11455 {
11457 tree tem_type;
11470 {
11473 }
11475 {
11478 }
11479 else
11481 }
11484 return
11490 arg1)));
11491 }
11493 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11494 already handled above. */
11499 {
11508 }
11510 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11511 is probably obsolete because the first operand should be a
11512 truth value (that's why we have the two cases above), but let's
11513 leave it in until we can confirm this for all front-ends. */
11525 /* Disable the transformations below for vectors, since
11526 fold_binary_op_with_conditional_arg may undo them immediately,
11527 yielding an infinite loop. */
11531 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11540 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11545 {
11547 /* Only perform transformation if ARG0 is easily inverted. */
11551 ? BIT_IOR_EXPR
11554 arg1);
11555 }
11557 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11562 {
11564 /* Only perform transformation if ARG0 is easily inverted. */
11570 op2);
11571 }
11573 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11585 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11586 of fold_ternary on them. */
11594 {
11604 {
11609 {
11617 }
11618 }
11619 }
11621 /* On constants we can use native encode/interpret to constant
11622 fold (nearly) all BIT_FIELD_REFs. */
11626 {
11629 /* Limit us to a reasonable amount of work. To relax the
11630 other limitations we need bit-shifting of the buffer
11631 and rounding up the size. */
11635 {
11637 unsigned HOST_WIDE_INT len
11642 {
11647 }
11648 }
11649 }
11654 /* For integers we can decompose the FMA if possible. */
11666 {
11682 {
11687 /* Make sure that the perm value is in an acceptable
11688 range. */
11697 else
11702 }
11705 {
11710 }
11715 {
11720 }
11726 {
11730 }
11735 /* Some targets are deficient and fail to expand a single
11736 argument permutation while still allowing an equivalent
11737 2-argument version. */
11741 {
11744 }
11747 {
11754 }
11758 }
11762 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11765 {
11771 wide_int tem2
11775 }
11780 {
11782 unsigned HOST_WIDE_INT elsize
11785 {
11789 else
11790 {
11796 }
11797 }
11798 }
11804 }
11806 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11807 of an array (or vector). */
11809 tree
11811 {
11816 {
11819 {
11820 /* Static constructors for variably sized objects makes no sense. */
11824 }
11825 }
11836 offset_int max_index;
11841 {
11842 /* Array constructor might explicitly set index, or specify a range,
11843 or leave index NULL meaning that it is next index after previous
11844 one. */
11846 {
11849 else
11850 {
11854 }
11855 }
11856 else
11857 {
11863 }
11865 /* Do we have match? */
11869 }
11871 }
11873 /* Perform constant folding and related simplification of EXPR.
11874 The related simplifications include x*1 => x, x*0 => 0, etc.,
11875 and application of the associative law.
11876 NOP_EXPR conversions may be removed freely (as long as we
11877 are careful not to change the type of the overall expression).
11878 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11879 but we can constant-fold them if they have constant operands. */
11881 #ifdef ENABLE_FOLD_CHECKING
11882 # define fold(x) fold_1 (x)
11884 static
11885 #endif
11886 tree
11888 {
11892 tree tem;
11895 /* Return right away if a constant. */
11899 /* CALL_EXPR-like objects with variable numbers of operands are
11900 treated specially. */
11902 {
11904 {
11907 }
11909 }
11912 {
11917 {
11935 }
11936 }
11939 {
11941 {
11948 {
11953 }
11956 }
11958 /* Return a VECTOR_CST if possible. */
11960 {
11966 tree val;
11972 }
11980 }
11982 #ifdef ENABLE_FOLD_CHECKING
11983 #undef fold
11990 /* When --enable-checking=fold, compute a digest of expr before
11991 and after actual fold call to see if fold did not accidentally
11992 change original expr. */
11994 tree
11996 {
11997 tree ret;
12017 }
12019 void
12021 {
12032 }
12034 static void
12036 {
12038 }
12040 static void
12043 {
12049 recursive_label:
12059 {
12060 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12065 }
12073 {
12074 /* Allow these fields to be modified. */
12075 tree tmp;
12084 {
12087 }
12088 }
12099 {
12102 {
12117 }
12121 {
12134 }
12151 {
12157 }
12160 {
12162 {
12165 }
12167 }
12178 {
12181 }
12191 }
12192 }
12194 /* Helper function for outputting the checksum of a tree T. When
12195 debugging with gdb, you can "define mynext" to be "next" followed
12196 by "call debug_fold_checksum (op0)", then just trace down till the
12197 outputs differ. */
12199 DEBUG_FUNCTION void
12201 {
12216 }
12218 #endif
12220 /* Fold a unary tree expression with code CODE of type TYPE with an
12221 operand OP0. LOC is the location of the resulting expression.
12222 Return a folded expression if successful. Otherwise, return a tree
12223 expression with code CODE of type TYPE with an operand OP0. */
12225 tree
12228 {
12229 tree tem;
12230 #ifdef ENABLE_FOLD_CHECKING
12239 #endif
12245 #ifdef ENABLE_FOLD_CHECKING
12252 #endif
12254 }
12256 /* Fold a binary tree expression with code CODE of type TYPE with
12257 operands OP0 and OP1. LOC is the location of the resulting
12258 expression. Return a folded expression if successful. Otherwise,
12259 return a tree expression with code CODE of type TYPE with operands
12260 OP0 and OP1. */
12262 tree
12265 MEM_STAT_DECL)
12266 {
12267 tree tem;
12268 #ifdef ENABLE_FOLD_CHECKING
12285 #endif
12291 #ifdef ENABLE_FOLD_CHECKING
12306 #endif
12308 }
12310 /* Fold a ternary tree expression with code CODE of type TYPE with
12311 operands OP0, OP1, and OP2. Return a folded expression if
12312 successful. Otherwise, return a tree expression with code CODE of
12313 type TYPE with operands OP0, OP1, and OP2. */
12315 tree
12318 {
12319 tree tem;
12320 #ifdef ENABLE_FOLD_CHECKING
12344 #endif
12351 #ifdef ENABLE_FOLD_CHECKING
12374 #endif
12376 }
12378 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12379 arguments in ARGARRAY, and a null static chain.
12380 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12381 of type TYPE from the given operands as constructed by build_call_array. */
12383 tree
12386 {
12387 tree tem;
12388 #ifdef ENABLE_FOLD_CHECKING
12407 #endif
12413 #ifdef ENABLE_FOLD_CHECKING
12429 #endif
12431 }
12433 /* Perform constant folding and related simplification of initializer
12434 expression EXPR. These behave identically to "fold_buildN" but ignore
12435 potential run-time traps and exceptions that fold must preserve. */
12437 #define START_FOLD_INIT \
12438 int saved_signaling_nans = flag_signaling_nans;\
12439 int saved_trapping_math = flag_trapping_math;\
12440 int saved_rounding_math = flag_rounding_math;\
12441 int saved_trapv = flag_trapv;\
12442 int saved_folding_initializer = folding_initializer;\
12443 flag_signaling_nans = 0;\
12444 flag_trapping_math = 0;\
12445 flag_rounding_math = 0;\
12446 flag_trapv = 0;\
12447 folding_initializer = 1;
12449 #define END_FOLD_INIT \
12450 flag_signaling_nans = saved_signaling_nans;\
12451 flag_trapping_math = saved_trapping_math;\
12452 flag_rounding_math = saved_rounding_math;\
12453 flag_trapv = saved_trapv;\
12454 folding_initializer = saved_folding_initializer;
12456 tree
12459 {
12460 tree result;
12461 START_FOLD_INIT;
12465 END_FOLD_INIT;
12467 }
12469 tree
12472 {
12473 tree result;
12474 START_FOLD_INIT;
12478 END_FOLD_INIT;
12480 }
12482 tree
12485 {
12486 tree result;
12487 START_FOLD_INIT;
12491 END_FOLD_INIT;
12493 }
12495 #undef START_FOLD_INIT
12496 #undef END_FOLD_INIT
12498 /* Determine if first argument is a multiple of second argument. Return 0 if
12499 it is not, or we cannot easily determined it to be.
12501 An example of the sort of thing we care about (at this point; this routine
12502 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12503 fold cases do now) is discovering that
12505 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12507 is a multiple of
12509 SAVE_EXPR (J * 8)
12511 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12513 This code also handles discovering that
12515 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12517 is a multiple of 8 so we don't have to worry about dealing with a
12518 possible remainder.
12520 Note that we *look* inside a SAVE_EXPR only to determine how it was
12521 calculated; it is not safe for fold to do much of anything else with the
12522 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12523 at run time. For example, the latter example above *cannot* be implemented
12524 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12525 evaluation time of the original SAVE_EXPR is not necessarily the same at
12526 the time the new expression is evaluated. The only optimization of this
12527 sort that would be valid is changing
12529 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12531 divided by 8 to
12533 SAVE_EXPR (I) * SAVE_EXPR (J)
12535 (where the same SAVE_EXPR (J) is used in the original and the
12536 transformed version). */
12538 int
12540 {
12548 {
12550 /* Bitwise and provides a power of two multiple. If the mask is
12551 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12554 /* FALLTHRU */
12567 {
12571 /* const_binop may not detect overflow correctly,
12572 so check for it explicitly here. */
12576 size_one_node,
12577 op1)))
12580 }
12584 /* Can't handle conversions from non-integral or wider integral type. */
12590 /* .. fall through ... */
12607 SIGNED);
12611 }
12612 }
12614 #define tree_expr_nonnegative_warnv_p(X, Y) \
12617 #define RECURSE(X) \
12618 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12620 /* Return true if CODE or TYPE is known to be non-negative. */
12622 static bool
12624 {
12627 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12628 have a signed:1 type (where the value is -1 and 0). */
12631 }
12633 /* Return true if (CODE OP0) is known to be non-negative. If the return
12634 value is based on the assumption that signed overflow is undefined,
12635 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12636 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12638 bool
12641 {
12646 {
12648 /* We can't return 1 if flag_wrapv is set because
12649 ABS_EXPR<INT_MIN> = INT_MIN. */
12653 {
12656 }
12664 CASE_CONVERT:
12665 {
12670 {
12674 {
12678 }
12679 }
12681 {
12687 }
12688 }
12693 }
12695 /* We don't know sign of `t', so be conservative and return false. */
12697 }
12699 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12700 value is based on the assumption that signed overflow is undefined,
12701 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12702 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12704 bool
12708 {
12713 {
12719 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12720 both unsigned and at least 2 bits shorter than the result. */
12724 {
12729 {
12733 }
12734 }
12739 {
12740 /* x * x is always non-negative for floating point x
12741 or without overflow. */
12744 {
12749 }
12750 }
12752 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12753 both unsigned and their total bits is shorter than the result. */
12757 {
12776 {
12786 }
12787 }
12814 }
12816 /* We don't know sign of `t', so be conservative and return false. */
12818 }
12820 /* Return true if T is known to be non-negative. If the return
12821 value is based on the assumption that signed overflow is undefined,
12822 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12823 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12825 bool
12827 {
12832 {
12846 /* Limit the depth of recursion to avoid quadratic behavior.
12847 This is expected to catch almost all occurrences in practice.
12848 If this code misses important cases that unbounded recursion
12849 would not, passes that need this information could be revised
12850 to provide it through dataflow propagation. */
12858 }
12859 }
12861 /* Return true if T is known to be non-negative. If the return
12862 value is based on the assumption that signed overflow is undefined,
12863 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12864 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12866 bool
12869 {
12871 {
12872 CASE_CFN_ACOS:
12873 CASE_CFN_ACOSH:
12874 CASE_CFN_CABS:
12875 CASE_CFN_COSH:
12876 CASE_CFN_ERFC:
12877 CASE_CFN_EXP:
12878 CASE_CFN_EXP10:
12879 CASE_CFN_EXP2:
12880 CASE_CFN_FABS:
12881 CASE_CFN_FDIM:
12882 CASE_CFN_HYPOT:
12883 CASE_CFN_POW10:
12884 CASE_CFN_FFS:
12885 CASE_CFN_PARITY:
12886 CASE_CFN_POPCOUNT:
12887 CASE_CFN_CLZ:
12888 CASE_CFN_CLRSB:
12891 /* Always true. */
12894 CASE_CFN_SQRT:
12895 /* sqrt(-0.0) is -0.0. */
12900 CASE_CFN_ASINH:
12901 CASE_CFN_ATAN:
12902 CASE_CFN_ATANH:
12903 CASE_CFN_CBRT:
12904 CASE_CFN_CEIL:
12905 CASE_CFN_ERF:
12906 CASE_CFN_EXPM1:
12907 CASE_CFN_FLOOR:
12908 CASE_CFN_FMOD:
12909 CASE_CFN_FREXP:
12910 CASE_CFN_ICEIL:
12911 CASE_CFN_IFLOOR:
12912 CASE_CFN_IRINT:
12913 CASE_CFN_IROUND:
12914 CASE_CFN_LCEIL:
12915 CASE_CFN_LDEXP:
12916 CASE_CFN_LFLOOR:
12917 CASE_CFN_LLCEIL:
12918 CASE_CFN_LLFLOOR:
12919 CASE_CFN_LLRINT:
12920 CASE_CFN_LLROUND:
12921 CASE_CFN_LRINT:
12922 CASE_CFN_LROUND:
12923 CASE_CFN_MODF:
12924 CASE_CFN_NEARBYINT:
12925 CASE_CFN_RINT:
12926 CASE_CFN_ROUND:
12927 CASE_CFN_SCALB:
12928 CASE_CFN_SCALBLN:
12929 CASE_CFN_SCALBN:
12930 CASE_CFN_SIGNBIT:
12931 CASE_CFN_SIGNIFICAND:
12932 CASE_CFN_SINH:
12933 CASE_CFN_TANH:
12934 CASE_CFN_TRUNC:
12935 /* True if the 1st argument is nonnegative. */
12938 CASE_CFN_FMAX:
12939 /* True if the 1st OR 2nd arguments are nonnegative. */
12942 CASE_CFN_FMIN:
12943 /* True if the 1st AND 2nd arguments are nonnegative. */
12946 CASE_CFN_COPYSIGN:
12947 /* True if the 2nd argument is nonnegative. */
12950 CASE_CFN_POWI:
12951 /* True if the 1st argument is nonnegative or the second
12952 argument is an even integer. */
12958 CASE_CFN_POW:
12959 /* True if the 1st argument is nonnegative or the second
12960 argument is an even integer valued real. */
12962 {
12963 REAL_VALUE_TYPE c;
12964 HOST_WIDE_INT n;
12969 {
12970 REAL_VALUE_TYPE cint;
12974 }
12975 }
12980 }
12982 }
12984 /* Return true if T is known to be non-negative. If the return
12985 value is based on the assumption that signed overflow is undefined,
12986 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12987 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12989 static bool
12991 {
12997 {
12999 {
13003 /* If the initializer is non-void, then it's a normal expression
13004 that will be assigned to the slot. */
13008 /* Otherwise, the initializer sets the slot in some way. One common
13009 way is an assignment statement at the end of the initializer. */
13011 {
13019 else
13021 }
13027 }
13030 {
13036 arg0,
13037 arg1,
13039 }
13052 }
13053 }
13055 #undef RECURSE
13056 #undef tree_expr_nonnegative_warnv_p
13058 /* Return true if T is known to be non-negative. If the return
13059 value is based on the assumption that signed overflow is undefined,
13060 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13061 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13063 bool
13065 {
13072 {
13094 }
13097 {
13123 }
13124 }
13126 /* Return true if `t' is known to be non-negative. Handle warnings
13127 about undefined signed overflow. */
13129 bool
13131 {
13138 "determining that expression is always "
13140 WARN_STRICT_OVERFLOW_MISC);
13142 }
13145 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13146 For floating point we further ensure that T is not denormal.
13147 Similar logic is present in nonzero_address in rtlanal.h.
13149 If the return value is based on the assumption that signed overflow
13150 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13151 change *STRICT_OVERFLOW_P. */
13153 bool
13156 {
13158 {
13161 strict_overflow_p);
13164 {
13170 strict_overflow_p));
13171 }
13176 strict_overflow_p);
13180 }
13183 }
13185 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13186 For floating point we further ensure that T is not denormal.
13187 Similar logic is present in nonzero_address in rtlanal.h.
13189 If the return value is based on the assumption that signed overflow
13190 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13191 change *STRICT_OVERFLOW_P. */
13193 bool
13195 tree type,
13196 tree op0,
13198 {
13201 {
13205 {
13206 /* With the presence of negative values it is hard
13207 to say something. */
13214 /* One of operands must be positive and the other non-negative. */
13215 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13216 overflows, on a twos-complement machine the sum of two
13217 nonnegative numbers can never be zero. */
13219 strict_overflow_p)
13221 strict_overflow_p));
13222 }
13227 {
13229 strict_overflow_p)
13231 strict_overflow_p))
13232 {
13235 }
13236 }
13245 {
13248 }
13255 {
13259 /* When both operands are nonzero, then MAX must be too. */
13261 strict_overflow_p))
13264 /* MAX where operand 0 is positive is positive. */
13266 strict_overflow_p);
13267 }
13268 /* MAX where operand 1 is positive is positive. */
13273 {
13277 }
13282 strict_overflow_p)
13284 strict_overflow_p));
13288 }
13291 }
13293 /* Return true when T is an address and is known to be nonzero.
13294 For floating point we further ensure that T is not denormal.
13295 Similar logic is present in nonzero_address in rtlanal.h.
13297 If the return value is based on the assumption that signed overflow
13298 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13299 change *STRICT_OVERFLOW_P. */
13301 bool
13303 {
13306 {
13311 {
13323 /* For objects in symbol table check if we know they are non-zero.
13324 Don't do anything for variables and functions before symtab is built;
13325 it is quite possible that they will be declared weak later. */
13330 /* Function local objects are never NULL. */
13337 /* Constants are never weak. */
13342 }
13350 {
13354 }
13359 }
13361 }
13363 #define integer_valued_real_p(X) \
13366 #define RECURSE(X) \
13367 ((integer_valued_real_p) (X, depth + 1))
13369 /* Return true if the floating point result of (CODE OP0) has an
13370 integer value. We also allow +Inf, -Inf and NaN to be considered
13371 integer values. Return false for signaling NaN.
13373 DEPTH is the current nesting depth of the query. */
13375 bool
13377 {
13379 {
13386 CASE_CONVERT:
13387 {
13394 }
13398 }
13400 }
13402 /* Return true if the floating point result of (CODE OP0 OP1) has an
13403 integer value. We also allow +Inf, -Inf and NaN to be considered
13404 integer values. Return false for signaling NaN.
13406 DEPTH is the current nesting depth of the query. */
13408 bool
13410 {
13412 {
13422 }
13424 }
13426 /* Return true if the floating point result of calling FNDECL with arguments
13427 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13428 considered integer values. Return false for signaling NaN. If FNDECL
13429 takes fewer than 2 arguments, the remaining ARGn are null.
13431 DEPTH is the current nesting depth of the query. */
13433 bool
13435 {
13437 {
13438 CASE_CFN_CEIL:
13439 CASE_CFN_FLOOR:
13440 CASE_CFN_NEARBYINT:
13441 CASE_CFN_RINT:
13442 CASE_CFN_ROUND:
13443 CASE_CFN_TRUNC:
13446 CASE_CFN_FMIN:
13447 CASE_CFN_FMAX:
13452 }
13454 }
13456 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13457 has an integer value. We also allow +Inf, -Inf and NaN to be
13458 considered integer values. Return false for signaling NaN.
13460 DEPTH is the current nesting depth of the query. */
13462 bool
13464 {
13466 {
13474 /* Limit the depth of recursion to avoid quadratic behavior.
13475 This is expected to catch almost all occurrences in practice.
13476 If this code misses important cases that unbounded recursion
13477 would not, passes that need this information could be revised
13478 to provide it through dataflow propagation. */
13482 depth));
13486 }
13488 }
13490 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13491 has an integer value. We also allow +Inf, -Inf and NaN to be
13492 considered integer values. Return false for signaling NaN.
13494 DEPTH is the current nesting depth of the query. */
13496 static bool
13498 {
13500 {
13511 }
13513 }
13515 #undef RECURSE
13516 #undef integer_valued_real_p
13518 /* Return true if the floating point expression T has an integer value.
13519 We also allow +Inf, -Inf and NaN to be considered integer values.
13520 Return false for signaling NaN.
13522 DEPTH is the current nesting depth of the query. */
13524 bool
13526 {
13532 {
13548 }
13551 {
13557 {
13566 }
13570 }
13571 }
13573 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13574 attempt to fold the expression to a constant without modifying TYPE,
13575 OP0 or OP1.
13577 If the expression could be simplified to a constant, then return
13578 the constant. If the expression would not be simplified to a
13579 constant, then return NULL_TREE. */
13581 tree
13583 {
13586 }
13588 /* Given the components of a unary expression CODE, TYPE and OP0,
13589 attempt to fold the expression to a constant without modifying
13590 TYPE or OP0.
13592 If the expression could be simplified to a constant, then return
13593 the constant. If the expression would not be simplified to a
13594 constant, then return NULL_TREE. */
13596 tree
13598 {
13601 }
13603 /* If EXP represents referencing an element in a constant string
13604 (either via pointer arithmetic or array indexing), return the
13605 tree representing the value accessed, otherwise return NULL. */
13607 tree
13609 {
13613 {
13615 tree index;
13616 tree string;
13621 else
13622 {
13626 /* Optimize the special-case of a zero lower bound.
13628 We convert the low_bound to sizetype to avoid some problems
13629 with constant folding. (E.g. suppose the lower bound is 1,
13630 and its mode is QI. Without the conversion,l (ARRAY
13631 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13632 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13638 }
13651 }
13653 }
13655 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13656 an integer constant, real, or fixed-point constant.
13658 TYPE is the type of the result. */
13660 static tree
13662 {
13666 {
13668 {
13675 }
13682 {
13683 FIXED_VALUE_TYPE f;
13688 /* Propagate overflow flags. */
13692 }
13696 }
13699 }
13701 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13702 an integer constant or real constant.
13704 TYPE is the type of the result. */
13706 tree
13708 {
13712 {
13714 {
13715 /* If the value is unsigned or non-negative, then the absolute value
13716 is the same as the ordinary value. */
13720 /* If the value is negative, then the absolute value is
13721 its negation. */
13722 else
13723 {
13728 }
13729 }
13735 else
13741 }
13744 }
13746 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13747 constant. TYPE is the type of the result. */
13749 static tree
13751 {
13755 }
13757 /* Given CODE, a relational operator, the target type, TYPE and two
13758 constant operands OP0 and OP1, return the result of the
13759 relational operation. If the result is not a compile time
13760 constant, then return NULL_TREE. */
13762 static tree
13764 {
13767 /* From here on, the only cases we handle are when the result is
13768 known to be a constant. */
13771 {
13775 /* Handle the cases where either operand is a NaN. */
13777 {
13779 {
13807 }
13810 }
13813 }
13816 {
13820 }
13822 /* Handle equality/inequality of complex constants. */
13824 {
13835 else
13837 }
13840 {
13842 {
13843 /* Have vector comparison with scalar boolean result. */
13848 {
13853 }
13857 }
13864 {
13876 }
13879 }
13881 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13883 To compute GT, swap the arguments and do LT.
13884 To compute GE, do LT and invert the result.
13885 To compute LE, swap the arguments, do LT and invert the result.
13886 To compute NE, do EQ and invert the result.
13888 Therefore, the code below must handle only EQ and LT. */
13891 {
13894 }
13896 /* Note that it is safe to invert for real values here because we
13897 have already handled the one case that it matters. */
13901 {
13904 }
13906 /* Compute a result for LT or EQ if args permit;
13907 Otherwise return T. */
13909 {
13912 else
13914 }
13915 else
13921 }
13923 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13924 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13925 itself. */
13927 tree
13929 {
13930 /* If the expression does not have side effects then we don't have to wrap
13931 it with a cleanup point expression. */
13935 /* If the expression is a return, check to see if the expression inside the
13936 return has no side effects or the right hand side of the modify expression
13937 inside the return. If either don't have side effects set we don't need to
13938 wrap the expression in a cleanup point expression. Note we don't check the
13939 left hand side of the modify because it should always be a return decl. */
13941 {
13948 }
13951 }
13953 /* Given a pointer value OP0 and a type TYPE, return a simplified version
13954 of an indirection through OP0, or NULL_TREE if no simplification is
13955 possible. */
13957 tree
13959 {
13961 tree subtype;
13969 {
13972 /* *&CONST_DECL -> to the value of the const decl. */
13975 /* *&p => p; make sure to handle *&"str"[cst] here. */
13977 {
13981 else
13983 }
13984 /* *(foo *)&fooarray => fooarray[0] */
13987 && (!in_gimple_form
13989 {
13999 }
14000 /* *(foo *)&complexfoo => __real__ complexfoo */
14004 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14007 {
14011 }
14012 }
14016 {
14022 {
14023 tree op00type;
14027 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14030 {
14032 unsigned HOST_WIDE_INT max_offset
14037 {
14044 }
14045 }
14046 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14049 {
14053 }
14054 /* ((foo *)&fooarray)[1] => fooarray[1] */
14057 {
14067 }
14068 }
14069 }
14071 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14074 && (!in_gimple_form
14076 {
14077 tree type_domain;
14087 NULL_TREE);
14088 }
14091 }
14093 /* Builds an expression for an indirection through T, simplifying some
14094 cases. */
14096 tree
14098 {
14106 }
14108 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14110 tree
14112 {
14117 else
14119 }
14121 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14122 whose result is ignored. The type of the returned tree need not be
14123 the same as the original expression. */
14125 tree
14127 {
14133 {
14144 else
14150 {
14166 }
14171 }
14172 }
14174 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14176 tree
14178 {
14184 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14185 have to do anything. Only do this when we are not given a const,
14186 because in that case, this check is more expensive than just
14187 doing it. */
14189 {
14194 }
14196 /* If divisor is a power of two, simplify this to bit manipulation. */
14198 {
14200 {
14214 }
14215 else
14216 {
14217 tree t;
14223 }
14224 }
14225 else
14226 {
14231 }
14234 }
14236 /* Likewise, but round down. */
14238 tree
14240 {
14247 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14248 have to do anything. Only do this when we are not given a const,
14249 because in that case, this check is more expensive than just
14250 doing it. */
14252 {
14257 }
14259 /* If divisor is a power of two, simplify this to bit manipulation. */
14261 {
14262 tree t;
14266 }
14267 else
14268 {
14273 }
14276 }
14278 /* Returns the pointer to the base of the object addressed by EXP and
14279 extracts the information about the offset of the access, storing it
14280 to PBITPOS and POFFSET. */
14282 static tree
14285 {
14286 tree core;
14287 machine_mode mode;
14289 HOST_WIDE_INT bitsize;
14293 {
14298 }
14299 else
14300 {
14304 }
14307 }
14309 /* Returns true if addresses of E1 and E2 differ by a constant, false
14310 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14312 bool
14314 {
14328 {
14338 }
14340 {
14341 /* If only one of the offsets is non-constant, the difference cannot
14342 be a constant. */
14344 }
14345 else
14350 }
14352 /* Return OFF converted to a pointer offset type suitable as offset for
14353 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14354 tree
14356 {
14358 }
14360 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14361 tree
14363 {
14366 }
14368 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14369 tree
14371 {
14374 }
14376 /* Return a char pointer for a C string if it is a string constant
14377 or sum of string constant and integer constant. */
14381 {
14382 tree offset_node;
14395 }
14397 #if CHECKING_P
14401 /* Helper functions for writing tests of folding trees. */
14403 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14405 static void
14407 tree constant)
14408 {
14410 }
14412 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14413 wrapping WRAPPED_EXPR. */
14415 static void
14417 tree wrapped_expr)
14418 {
14423 }
14425 /* Verify that various arithmetic binary operations are folded
14426 correctly. */
14428 static void
14430 {
14436 /* Addition. */
14437 /* 1 <-- (0 + 1) */
14439 one);
14441 one);
14443 /* (nonlvalue)x <-- (x + 0) */
14445 x);
14447 /* Subtraction. */
14448 /* 0 <-- (x - x) */
14450 zero);
14452 x);
14454 /* Multiplication. */
14455 /* 0 <-- (x * 0) */
14457 zero);
14459 /* (nonlvalue)x <-- (x * 1) */
14461 x);
14462 }
14464 /* Run all of the selftests within this file. */
14466 void
14468 {
14470 }