| blob | 736552c33a9af3876bfd01f3cf47a078dec6558b |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2017 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. */
83 /* Nonzero if we are folding constants inside an initializer; zero
84 otherwise. */
87 /* The following constants represent a bit based encoding of GCC's
88 comparison operators. This encoding simplifies transformations
89 on relational comparison operators, such as AND and OR. */
107 };
145 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
146 Otherwise, return LOC. */
148 static location_t
150 {
153 }
155 /* Similar to protected_set_expr_location, but never modify x in place,
156 if location can and needs to be set, unshare it. */
160 {
166 {
169 }
171 }
172 \f
173 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
174 division and returns the quotient. Otherwise returns
175 NULL_TREE. */
177 tree
179 {
180 widest_int quo;
187 }
188 \f
189 /* This is nonzero if we should defer warnings about undefined
190 overflow. This facility exists because these warnings are a
191 special case. The code to estimate loop iterations does not want
192 to issue any warnings, since it works with expressions which do not
193 occur in user code. Various bits of cleanup code call fold(), but
194 only use the result if it has certain characteristics (e.g., is a
195 constant); that code only wants to issue a warning if the result is
196 used. */
200 /* If a warning about undefined overflow is deferred, this is the
201 warning. Note that this may cause us to turn two warnings into
202 one, but that is fine since it is sufficient to only give one
203 warning per expression. */
207 /* If a warning about undefined overflow is deferred, this is the
208 level at which the warning should be emitted. */
212 /* Start deferring overflow warnings. We could use a stack here to
213 permit nested calls, but at present it is not necessary. */
215 void
217 {
219 }
221 /* Stop deferring overflow warnings. If there is a pending warning,
222 and ISSUE is true, then issue the warning if appropriate. STMT is
223 the statement with which the warning should be associated (used for
224 location information); STMT may be NULL. CODE is the level of the
225 warning--a warn_strict_overflow_code value. This function will use
226 the smaller of CODE and the deferred code when deciding whether to
227 issue the warning. CODE may be zero to mean to always use the
228 deferred code. */
230 void
232 {
234 location_t locus;
239 {
245 }
256 /* Use the smallest code level when deciding to issue the
257 warning. */
266 else
269 }
271 /* Stop deferring overflow warnings, ignoring any deferred
272 warnings. */
274 void
276 {
278 }
280 /* Whether we are deferring overflow warnings. */
282 bool
284 {
286 }
288 /* This is called when we fold something based on the fact that signed
289 overflow is undefined. */
291 void
293 {
295 {
298 {
301 }
302 }
305 }
306 \f
307 /* Return true if the built-in mathematical function specified by CODE
308 is odd, i.e. -f(x) == f(-x). */
310 bool
312 {
314 {
315 CASE_CFN_ASIN:
316 CASE_CFN_ASINH:
317 CASE_CFN_ATAN:
318 CASE_CFN_ATANH:
319 CASE_CFN_CASIN:
320 CASE_CFN_CASINH:
321 CASE_CFN_CATAN:
322 CASE_CFN_CATANH:
323 CASE_CFN_CBRT:
324 CASE_CFN_CPROJ:
325 CASE_CFN_CSIN:
326 CASE_CFN_CSINH:
327 CASE_CFN_CTAN:
328 CASE_CFN_CTANH:
329 CASE_CFN_ERF:
330 CASE_CFN_LLROUND:
331 CASE_CFN_LROUND:
332 CASE_CFN_ROUND:
333 CASE_CFN_SIN:
334 CASE_CFN_SINH:
335 CASE_CFN_TAN:
336 CASE_CFN_TANH:
337 CASE_CFN_TRUNC:
340 CASE_CFN_LLRINT:
341 CASE_CFN_LRINT:
342 CASE_CFN_NEARBYINT:
343 CASE_CFN_RINT:
348 }
350 }
352 /* Check whether we may negate an integer constant T without causing
353 overflow. */
355 bool
357 {
358 tree type;
367 }
369 /* Determine whether an expression T can be cheaply negated using
370 the function negate_expr without introducing undefined overflow. */
372 static bool
374 {
375 tree type;
384 {
389 /* Check that -CST will not overflow type. */
402 /* We want to canonicalize to positive real constants. Pretend
403 that only negative ones can be easily negated. */
411 {
422 }
437 /* -(A + B) -> (-B) - A. */
440 /* -(A + B) -> (-A) - B. */
444 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
453 /* INT_MIN/n * n doesn't overflow while negating one operand it does
454 if n is a (negative) power of two. */
463 /* Fall through. */
478 /* In general we can't negate B in A / B, because if A is INT_MIN and
479 B is 1, we may turn this into INT_MIN / -1 which is undefined
480 and actually traps on some architectures. */
489 /* Negate -((double)float) as (double)(-float). */
491 {
495 }
499 /* Negate -f(x) as f(-x). */
505 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
507 {
511 }
516 }
518 }
520 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
521 simplification is possible.
522 If negate_expr_p would return true for T, NULL_TREE will never be
523 returned. */
525 static tree
527 {
529 tree tem;
532 {
533 /* Convert - (~A) to A + 1. */
559 {
564 }
568 {
573 {
577 }
580 }
603 {
604 /* -(A + B) -> (-B) - A. */
606 {
610 }
612 /* -(A + B) -> (-A) - B. */
614 {
618 }
619 }
623 /* - (A - B) -> B - A */
634 /* Fall through. */
638 {
647 }
659 /* In general we can't negate B in A / B, because if A is INT_MIN and
660 B is 1, we may turn this into INT_MIN / -1 which is undefined
661 and actually traps on some architectures. */
673 /* Convert -((double)float) into (double)(-float). */
675 {
679 }
683 /* Negate -f(x) as f(-x). */
686 {
692 }
696 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
698 {
701 {
708 }
709 }
714 }
717 }
719 /* A wrapper for fold_negate_expr_1. */
721 static tree
723 {
730 }
732 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
733 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
734 return NULL_TREE. */
736 static tree
738 {
740 location_t loc;
753 }
754 \f
755 /* Split a tree IN into a constant, literal and variable parts that could be
756 combined with CODE to make IN. "constant" means an expression with
757 TREE_CONSTANT but that isn't an actual constant. CODE must be a
758 commutative arithmetic operation. Store the constant part into *CONP,
759 the literal in *LITP and return the variable part. If a part isn't
760 present, set it to null. If the tree does not decompose in this way,
761 return the entire tree as the variable part and the other parts as null.
763 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
764 case, we negate an operand that was subtracted. Except if it is a
765 literal for which we use *MINUS_LITP instead.
767 If NEGATE_P is true, we are negating all of IN, again except a literal
768 for which we use *MINUS_LITP instead. If a variable part is of pointer
769 type, it is negated after converting to TYPE. This prevents us from
770 generating illegal MINUS pointer expression. LOC is the location of
771 the converted variable part.
773 If IN is itself a literal or constant, return it as appropriate.
775 Note that we do not guarantee that any of the three values will be the
776 same type as IN, but they will have the same signedness and mode. */
778 static tree
781 {
788 /* Strip any conversions that don't change the machine mode or signedness. */
797 /* We can associate addition and subtraction together (even
798 though the C standard doesn't say so) for integers because
799 the value is not affected. For reals, the value might be
800 affected, so we can't. */
806 {
812 /* First see if either of the operands is a literal, then a constant. */
825 /* If we haven't dealt with either operand, this is not a case we can
826 decompose. Otherwise, VAR is either of the ones remaining, if any. */
831 else
834 /* Now do any needed negations. */
838 {
839 /* Convert to TYPE before negating. */
842 }
844 {
845 /* Convert to TYPE before negating. */
848 }
849 }
854 {
855 /* -X - 1 is folded to ~X, undo that here. Do _not_ do this
856 when IN is constant. */
859 }
860 else
864 {
870 {
871 /* Convert to TYPE before negating. */
874 }
876 {
877 /* Convert to TYPE before negating. */
880 }
881 }
884 }
886 /* Re-associate trees split by the above function. T1 and T2 are
887 either expressions to associate or null. Return the new
888 expression, if any. LOC is the location of the new expression. If
889 we build an operation, do it in TYPE and with CODE. */
891 static tree
893 {
899 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
900 try to fold this since we will have infinite recursion. But do
901 deal with any NEGATE_EXPRs. */
904 {
906 {
919 }
921 {
924 }
928 }
932 }
933 \f
934 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
935 for use in int_const_binop, size_binop and size_diffop. */
937 static bool
939 {
946 {
955 }
960 }
963 /* Combine two integer constants ARG1 and ARG2 under operation CODE
964 to produce a new constant. Return NULL_TREE if we don't know how
965 to evaluate CODE at compile-time. */
967 static tree
970 {
971 wide_int res;
972 tree t;
980 {
996 {
1000 else
1002 }
1005 /* It's unclear from the C standard whether shifts can overflow.
1006 The following code ignores overflow; perhaps a C standard
1007 interpretation ruling is needed. */
1009 else
1016 {
1020 else
1022 }
1026 else
1105 }
1113 }
1115 tree
1117 {
1119 }
1121 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1122 constant. We assume ARG1 and ARG2 have the same data type, or at least
1123 are the same kind of constant and the same machine mode. Return zero if
1124 combining the constants is not allowed in the current operating mode. */
1126 static tree
1128 {
1129 /* Sanity check for the recursive cases. */
1137 {
1143 }
1146 {
1147 machine_mode mode;
1148 REAL_VALUE_TYPE d1;
1149 REAL_VALUE_TYPE d2;
1150 REAL_VALUE_TYPE value;
1151 REAL_VALUE_TYPE result;
1155 /* The following codes are handled by real_arithmetic. */
1157 {
1168 }
1176 /* Don't perform operation if we honor signaling NaNs and
1177 either operand is a signaling NaN. */
1183 /* Don't perform operation if it would raise a division
1184 by zero exception. */
1190 /* If either operand is a NaN, just return it. Otherwise, set up
1191 for floating-point trap; we return an overflow. */
1193 {
1194 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1195 is off. */
1199 }
1201 {
1202 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1203 is off. */
1207 }
1212 /* Don't constant fold this floating point operation if
1213 the result has overflowed and flag_trapping_math. */
1221 /* Don't constant fold this floating point operation if the
1222 result may dependent upon the run-time rounding mode and
1223 flag_rounding_math is set, or if GCC's software emulation
1224 is unable to accurately represent the result. */
1234 }
1237 {
1238 FIXED_VALUE_TYPE f1;
1239 FIXED_VALUE_TYPE f2;
1240 FIXED_VALUE_TYPE result;
1245 /* The following codes are handled by fixed_arithmetic. */
1247 {
1259 {
1266 }
1271 }
1278 /* Propagate overflow flags. */
1282 }
1285 {
1294 {
1305 mpc_mul);
1319 mpc_div);
1320 /* Fallthru. */
1326 {
1327 /* Keep this algorithm in sync with
1328 tree-complex.c:expand_complex_div_straight().
1330 Expand complex division to scalars, straightforward algorithm.
1331 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1332 t = br*br + bi*bi
1333 */
1334 tree magsquared
1338 tree t1
1342 tree t2
1349 }
1350 else
1351 {
1352 /* Keep this algorithm in sync with
1353 tree-complex.c:expand_complex_div_wide().
1355 Expand complex division to scalars, modified algorithm to minimize
1356 overflow with wide input ranges. */
1362 {
1363 /* In the TRUE branch, we compute
1364 ratio = br/bi;
1365 div = (br * ratio) + bi;
1366 tr = (ar * ratio) + ai;
1367 ti = (ai * ratio) - ar;
1368 tr = tr / div;
1369 ti = ti / div; */
1380 }
1381 else
1382 {
1383 /* In the FALSE branch, we compute
1384 ratio = d/c;
1385 divisor = (d * ratio) + c;
1386 tr = (b * ratio) + a;
1387 ti = b - (a * ratio);
1388 tr = tr / div;
1389 ti = ti / div; */
1401 }
1402 }
1407 }
1411 }
1415 {
1421 {
1427 /* It is possible that const_binop cannot handle the given
1428 code and return NULL_TREE */
1431 }
1434 }
1436 /* Shifts allow a scalar offset for a vector. */
1439 {
1445 {
1450 /* It is possible that const_binop cannot handle the given
1451 code and return NULL_TREE. */
1454 }
1457 }
1459 }
1461 /* Overload that adds a TYPE parameter to be able to dispatch
1462 to fold_relational_const. */
1464 tree
1466 {
1470 /* ??? Until we make the const_binop worker take the type of the
1471 result as argument put those cases that need it here. */
1473 {
1484 {
1500 {
1506 }
1509 }
1515 {
1540 {
1553 }
1556 }
1559 }
1564 /* Make sure type and arg0 have the same saturating flag. */
1569 }
1571 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1572 Return zero if computing the constants is not possible. */
1574 tree
1576 {
1577 /* Don't perform the operation, other than NEGATE and ABS, if
1578 flag_signaling_nans is on and the operand is a signaling NaN. */
1587 {
1588 CASE_CONVERT:
1595 /* If the source address is 0, and the source address space
1596 cannot have a valid object at 0, fold to dest type null. */
1607 {
1608 /* Can't call fold_negate_const directly here as that doesn't
1609 handle all cases and we might not be able to negate some
1610 constants. */
1615 }
1624 {
1628 }
1634 /* Perform BIT_NOT_EXPR on each element individually. */
1636 {
1638 tree elem;
1643 {
1649 }
1652 }
1674 {
1693 else
1697 {
1701 }
1704 }
1709 {
1723 {
1728 }
1731 {
1735 }
1738 }
1742 }
1745 }
1747 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1748 indicates which particular sizetype to create. */
1750 tree
1752 {
1754 }
1755 \f
1756 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1757 is a tree code. The type of the result is taken from the operands.
1758 Both must be equivalent integer types, ala int_binop_types_match_p.
1759 If the operands are constant, so is the result. */
1761 tree
1763 {
1772 /* Handle the special case of two integer constants faster. */
1774 {
1775 /* And some specific cases even faster than that. */
1777 {
1782 }
1784 {
1787 }
1789 {
1792 }
1794 /* Handle general case of two integer constants. For sizetype
1795 constant calculations we always want to know about overflow,
1796 even in the unsigned case. */
1798 }
1801 }
1803 /* Given two values, either both of sizetype or both of bitsizetype,
1804 compute the difference between the two values. Return the value
1805 in signed type corresponding to the type of the operands. */
1807 tree
1809 {
1811 tree ctype;
1816 /* If the type is already signed, just do the simple thing. */
1824 else
1827 /* If either operand is not a constant, do the conversions to the signed
1828 type and subtract. The hardware will do the right thing with any
1829 overflow in the subtraction. */
1835 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1836 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1837 overflow) and negate (which can't either). Special-case a result
1838 of zero while we're here. */
1844 else
1848 MINUS_EXPR,
1850 }
1851 \f
1852 /* A subroutine of fold_convert_const handling conversions of an
1853 INTEGER_CST to another integer type. */
1855 static tree
1857 {
1858 /* Given an integer constant, make new constant with new type,
1859 appropriately sign-extended or truncated. Use widest_int
1860 so that any extension is done according ARG1's type. */
1864 }
1866 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1867 to an integer type. */
1869 static tree
1871 {
1873 tree t;
1875 /* The following code implements the floating point to integer
1876 conversion rules required by the Java Language Specification,
1877 that IEEE NaNs are mapped to zero and values that overflow
1878 the target precision saturate, i.e. values greater than
1879 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1880 are mapped to INT_MIN. These semantics are allowed by the
1881 C and C++ standards that simply state that the behavior of
1882 FP-to-integer conversion is unspecified upon overflow. */
1884 wide_int val;
1885 REAL_VALUE_TYPE r;
1889 {
1896 }
1898 /* If R is NaN, return zero and show we have an overflow. */
1900 {
1903 }
1905 /* See if R is less than the lower bound or greater than the
1906 upper bound. */
1909 {
1913 {
1916 }
1917 }
1920 {
1923 {
1926 {
1929 }
1930 }
1931 }
1938 }
1940 /* A subroutine of fold_convert_const handling conversions of a
1941 FIXED_CST to an integer type. */
1943 static tree
1945 {
1946 tree t;
1950 /* Right shift FIXED_CST to temp by fbit. */
1954 {
1956 HOST_BITS_PER_DOUBLE_INT,
1959 /* Left shift temp to temp_trunc by fbit. */
1961 HOST_BITS_PER_DOUBLE_INT,
1963 }
1964 else
1965 {
1968 }
1970 /* If FIXED_CST is negative, we need to round the value toward 0.
1971 By checking if the fractional bits are not zero to add 1 to temp. */
1977 /* Given a fixed-point constant, make new constant with new type,
1978 appropriately sign-extended or truncated. */
1986 }
1988 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1989 to another floating point type. */
1991 static tree
1993 {
1994 REAL_VALUE_TYPE value;
1995 tree t;
1997 /* Don't perform the operation if flag_signaling_nans is on
1998 and the operand is a signaling NaN. */
2006 /* If converting an infinity or NAN to a representation that doesn't
2007 have one, set the overflow bit so that we can produce some kind of
2008 error message at the appropriate point if necessary. It's not the
2009 most user-friendly message, but it's better than nothing. */
2016 /* Regular overflow, conversion produced an infinity in a mode that
2017 can't represent them. */
2022 else
2025 }
2027 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2028 to a floating point type. */
2030 static tree
2032 {
2033 REAL_VALUE_TYPE value;
2034 tree t;
2041 }
2043 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2044 to another fixed-point type. */
2046 static tree
2048 {
2049 FIXED_VALUE_TYPE value;
2050 tree t;
2057 /* Propagate overflow flags. */
2061 }
2063 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2064 to a fixed-point type. */
2066 static tree
2068 {
2069 FIXED_VALUE_TYPE value;
2070 tree t;
2072 double_int di;
2079 else
2087 /* Propagate overflow flags. */
2091 }
2093 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2094 to a fixed-point type. */
2096 static tree
2098 {
2099 FIXED_VALUE_TYPE value;
2100 tree t;
2108 /* Propagate overflow flags. */
2112 }
2114 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2115 type TYPE. If no simplification can be done return NULL_TREE. */
2117 static tree
2119 {
2125 {
2132 }
2134 {
2141 }
2143 {
2150 }
2152 {
2155 {
2160 {
2166 }
2168 }
2169 }
2171 }
2173 /* Construct a vector of zero elements of vector type TYPE. */
2175 static tree
2177 {
2178 tree t;
2182 }
2184 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2186 bool
2188 {
2203 {
2218 }
2219 }
2221 /* Convert expression ARG to type TYPE. Used by the middle-end for
2222 simple conversions in preference to calling the front-end's convert. */
2224 tree
2226 {
2228 tree tem;
2239 {
2242 /* Handle conversions between pointers to different address spaces. */
2247 /* fall through */
2252 {
2256 }
2270 {
2274 }
2276 {
2280 }
2282 {
2286 }
2289 {
2307 }
2312 {
2316 }
2319 {
2333 }
2337 {
2346 integer_zero_node));
2348 {
2352 {
2358 }
2366 }
2370 }
2388 }
2389 fold_convert_exit:
2392 }
2393 \f
2394 /* Return false if expr can be assumed not to be an lvalue, true
2395 otherwise. */
2397 static bool
2399 {
2400 /* We only need to wrap lvalue tree codes. */
2402 {
2433 /* Assume the worst for front-end tree codes. */
2437 }
2440 }
2442 /* Return an expr equal to X but certainly not valid as an lvalue. */
2444 tree
2446 {
2447 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2448 us. */
2455 }
2457 /* When pedantic, return an expr equal to X but certainly not valid as a
2458 pedantic lvalue. Otherwise, return X. */
2460 static tree
2462 {
2464 }
2465 \f
2466 /* Given a tree comparison code, return the code that is the logical inverse.
2467 It is generally not safe to do this for floating-point comparisons, except
2468 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2469 ERROR_MARK in this case. */
2471 enum tree_code
2473 {
2479 {
2510 }
2511 }
2513 /* Similar, but return the comparison that results if the operands are
2514 swapped. This is safe for floating-point. */
2516 enum tree_code
2518 {
2520 {
2546 }
2547 }
2550 /* Convert a comparison tree code from an enum tree_code representation
2551 into a compcode bit-based encoding. This function is the inverse of
2552 compcode_to_comparison. */
2554 static enum comparison_code
2556 {
2558 {
2589 }
2590 }
2592 /* Convert a compcode bit-based encoding of a comparison operator back
2593 to GCC's enum tree_code representation. This function is the
2594 inverse of comparison_to_compcode. */
2596 static enum tree_code
2598 {
2600 {
2631 }
2632 }
2634 /* Return a tree for the comparison which is the combination of
2635 doing the AND or OR (depending on CODE) of the two operations LCODE
2636 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2637 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2638 if this makes the transformation invalid. */
2640 tree
2645 {
2652 {
2663 }
2666 {
2667 /* Eliminate unordered comparisons, as well as LTGT and ORD
2668 which are not used unless the mode has NaNs. */
2674 }
2676 {
2677 /* Check that the original operation and the optimized ones will trap
2678 under the same condition. */
2689 /* In a short-circuited boolean expression the LHS might be
2690 such that the RHS, if evaluated, will never trap. For
2691 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2692 if neither x nor y is NaN. (This is a mixed blessing: for
2693 example, the expression above will never trap, hence
2694 optimizing it to x < y would be invalid). */
2699 /* If the comparison was short-circuited, and only the RHS
2700 trapped, we may now generate a spurious trap. */
2705 /* If we changed the conditions that cause a trap, we lose. */
2708 }
2714 else
2715 {
2720 }
2721 }
2722 \f
2723 /* Return nonzero if two operands (typically of the same tree node)
2724 are necessarily equal. FLAGS modifies behavior as follows:
2726 If OEP_ONLY_CONST is set, only return nonzero for constants.
2727 This function tests whether the operands are indistinguishable;
2728 it does not test whether they are equal using C's == operation.
2729 The distinction is important for IEEE floating point, because
2730 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2731 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2733 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2734 even though it may hold multiple values during a function.
2735 This is because a GCC tree node guarantees that nothing else is
2736 executed between the evaluation of its "operands" (which may often
2737 be evaluated in arbitrary order). Hence if the operands themselves
2738 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2739 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2740 unset means assuming isochronic (or instantaneous) tree equivalence.
2741 Unless comparing arbitrary expression trees, such as from different
2742 statements, this flag can usually be left unset.
2744 If OEP_PURE_SAME is set, then pure functions with identical arguments
2745 are considered the same. It is used when the caller has other ways
2746 to ensure that global memory is unchanged in between.
2748 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2749 not values of expressions.
2751 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2752 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2754 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2755 any operand with side effect. This is unnecesarily conservative in the
2756 case we know that arg0 and arg1 are in disjoint code paths (such as in
2757 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2758 addresses with TREE_CONSTANT flag set so we know that &var == &var
2759 even if var is volatile. */
2761 int
2763 {
2764 /* When checking, verify at the outermost operand_equal_p call that
2765 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2766 hash value. */
2768 {
2770 {
2772 {
2779 }
2781 }
2782 else
2784 }
2786 /* If either is ERROR_MARK, they aren't equal. */
2792 /* Similar, if either does not have a type (like a released SSA name),
2793 they aren't equal. */
2797 /* We cannot consider pointers to different address space equal. */
2804 /* Check equality of integer constants before bailing out due to
2805 precision differences. */
2807 {
2808 /* Address of INTEGER_CST is not defined; check that we did not forget
2809 to drop the OEP_ADDRESS_OF flags. */
2812 }
2815 {
2816 /* If both types don't have the same signedness, then we can't consider
2817 them equal. We must check this before the STRIP_NOPS calls
2818 because they may change the signedness of the arguments. As pointers
2819 strictly don't have a signedness, require either two pointers or
2820 two non-pointers as well. */
2826 /* If both types don't have the same precision, then it is not safe
2827 to strip NOPs. */
2834 }
2835 #if 0
2836 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2837 sanity check once the issue is solved. */
2838 else
2839 /* Addresses of conversions and SSA_NAMEs (and many other things)
2840 are not defined. Check that we did not forget to drop the
2841 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2844 #endif
2846 /* In case both args are comparisons but with different comparison
2847 code, try to swap the comparison operands of one arg to produce
2848 a match and compare that variant. */
2852 {
2860 }
2863 {
2864 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2866 ;
2868 {
2869 /* If we are interested in comparing addresses ignore
2870 MEM_REF wrappings of the base that can appear just for
2871 TBAA reasons. */
2885 }
2886 else
2888 }
2890 /* When not checking adddresses, this is needed for conversions and for
2891 COMPONENT_REF. Might as well play it safe and always test this. */
2898 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2899 We don't care about side effects in that case because the SAVE_EXPR
2900 takes care of that for us. In all other cases, two expressions are
2901 equal if they have no side effects. If we have two identical
2902 expressions with side effects that should be treated the same due
2903 to the only side effects being identical SAVE_EXPR's, that will
2904 be detected in the recursive calls below.
2905 If we are taking an invariant address of two identical objects
2906 they are necessarily equal as well. */
2913 /* Next handle constant cases, those for which we can return 1 even
2914 if ONLY_CONST is set. */
2917 {
2931 {
2932 /* If we do not distinguish between signed and unsigned zero,
2933 consider them equal. */
2936 }
2940 {
2947 {
2951 }
2953 }
2957 flags)
2959 flags));
2970 flags | OEP_ADDRESS_OF
2973 /* In GIMPLE empty constructors are allowed in initializers of
2974 aggregates. */
2978 }
2983 /* Define macros to test an operand from arg0 and arg1 for equality and a
2984 variant that allows null and views null as being different from any
2985 non-null value. In the latter case, if either is null, the both
2986 must be; otherwise, do the normal comparison. */
2987 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2988 TREE_OPERAND (arg1, N), flags)
2990 #define OP_SAME_WITH_NULL(N) \
2991 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2992 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2995 {
2997 /* Two conversions are equal only if signedness and modes match. */
2999 {
3000 CASE_CONVERT:
3008 }
3018 /* For commutative ops, allow the other order. */
3026 /* If either of the pointer (or reference) expressions we are
3027 dereferencing contain a side effect, these cannot be equal,
3028 but their addresses can be. */
3035 {
3045 /* Require the same offset. */
3051 /* Fallthru. */
3059 {
3060 /* Require equal access sizes */
3066 flags)))
3068 /* Verify that access happens in similar types. */
3071 /* Verify that accesses are TBAA compatible. */
3080 /* Verify that alignment is compatible. */
3084 }
3087 /* TARGET_MEM_REF require equal extra operands. */
3098 /* Compare the array index by value if it is constant first as we
3099 may have different types but same value here. */
3105 /* Compare low bound and element size as with OEP_ADDRESS_OF
3106 we have to account for the offset of the ref. */
3111 array_ref_low_bound
3115 array_ref_element_size
3117 flags))));
3120 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3121 may be NULL when we're called to compare MEM_EXPRs. */
3136 }
3140 {
3142 /* Be sure we pass right ADDRESS_OF flag. */
3160 /* The multiplcation operands are commutative. */
3161 /* FALLTHRU */
3169 /* Otherwise take into account this is a commutative operation. */
3205 }
3209 {
3213 /* If not both CALL_EXPRs are either internal or normal function
3214 functions, then they are not equal. */
3217 {
3218 /* If the CALL_EXPRs call different internal functions, then they
3219 are not equal. */
3222 }
3223 else
3224 {
3225 /* If the CALL_EXPRs call different functions, then they are not
3226 equal. */
3228 flags))
3230 }
3232 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3233 {
3237 else
3241 }
3243 /* Now see if all the arguments are the same. */
3244 {
3255 /* If we get here and both argument lists are exhausted
3256 then the CALL_EXPRs are equal. */
3258 }
3261 }
3264 /* Consider __builtin_sqrt equal to sqrt. */
3272 {
3273 /* In GIMPLE constructors are used only to build vectors from
3274 elements. Individual elements in the constructor must be
3275 indexed in increasing order and form an initial sequence.
3277 We make no effort to compare constructors in generic.
3278 (see sem_variable::equals in ipa-icf which can do so for
3279 constants). */
3284 /* Be sure that vectors constructed have the same representation.
3285 We only tested element precision and modes to match.
3286 Vectors may be BLKmode and thus also check that the number of
3287 parts match. */
3300 {
3305 /* In GIMPLE the indexes can be either NULL or matching i.
3306 Double check this so we won't get false
3307 positives for GENERIC. */
3315 }
3317 }
3320 {
3321 /* Compare the STATEMENT_LISTs. */
3327 {
3328 /* The lists don't have the same number of statements. */
3334 OEP_LEXICOGRAPHIC))
3336 }
3337 }
3342 {
3349 }
3353 }
3355 #undef OP_SAME
3356 #undef OP_SAME_WITH_NULL
3357 }
3358 \f
3359 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3360 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3362 When in doubt, return 0. */
3364 static int
3366 {
3378 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3379 and see if the inner values are the same. This removes any
3380 signedness comparison, which doesn't matter here. */
3387 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3388 actual comparison operand, ARG0.
3390 First throw away any conversions to wider types
3391 already present in the operands. */
3400 {
3403 /* Make sure shorter operand is extended the right way
3404 to match the longer operand. */
3410 }
3413 }
3414 \f
3415 /* See if ARG is an expression that is either a comparison or is performing
3416 arithmetic on comparisons. The comparisons must only be comparing
3417 two different values, which will be stored in *CVAL1 and *CVAL2; if
3418 they are nonzero it means that some operands have already been found.
3419 No variables may be used anywhere else in the expression except in the
3420 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3421 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3423 If this is true, return 1. Otherwise, return zero. */
3425 static int
3427 {
3431 /* We can handle some of the tcc_expression cases here. */
3441 {
3442 /* If we've already found a CVAL1 or CVAL2, this expression is
3443 two complex to handle. */
3449 }
3452 {
3475 /* First see if we can handle the first operand, then the second. For
3476 the second operand, we know *CVAL1 can't be zero. It must be that
3477 one side of the comparison is each of the values; test for the
3478 case where this isn't true by failing if the two operands
3479 are the same. */
3488 ;
3492 ;
3493 else
3497 ;
3501 ;
3502 else
3509 }
3510 }
3511 \f
3512 /* ARG is a tree that is known to contain just arithmetic operations and
3513 comparisons. Evaluate the operations in the tree substituting NEW0 for
3514 any occurrence of OLD0 as an operand of a comparison and likewise for
3515 NEW1 and OLD1. */
3517 static tree
3520 {
3525 /* We can handle some of the tcc_expression cases here. */
3533 {
3548 {
3567 }
3568 /* Fall through - ??? */
3571 {
3575 /* We need to check both for exact equality and tree equality. The
3576 former will be true if the operand has a side-effect. In that
3577 case, we know the operand occurred exactly once. */
3590 }
3594 }
3595 }
3596 \f
3597 /* Return a tree for the case when the result of an expression is RESULT
3598 converted to TYPE and OMITTED was previously an operand of the expression
3599 but is now not needed (e.g., we folded OMITTED * 0).
3601 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3602 the conversion of RESULT to TYPE. */
3604 tree
3606 {
3609 /* If the resulting operand is an empty statement, just return the omitted
3610 statement casted to void. */
3620 }
3622 /* Return a tree for the case when the result of an expression is RESULT
3623 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3624 of the expression but are now not needed.
3626 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3627 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3628 evaluated before OMITTED2. Otherwise, if neither has side effects,
3629 just do the conversion of RESULT to TYPE. */
3631 tree
3634 {
3643 }
3645 \f
3646 /* Return a simplified tree node for the truth-negation of ARG. This
3647 never alters ARG itself. We assume that ARG is an operation that
3648 returns a truth value (0 or 1).
3650 FIXME: one would think we would fold the result, but it causes
3651 problems with the dominator optimizer. */
3653 static tree
3655 {
3660 /* If this is a comparison, we can simply invert it, except for
3661 floating-point non-equality comparisons, in which case we just
3662 enclose a TRUTH_NOT_EXPR around what we have. */
3665 {
3668 && flag_trapping_math
3682 }
3685 {
3704 /* Here we can invert either operand. We invert the first operand
3705 unless the second operand is a TRUTH_NOT_EXPR in which case our
3706 result is the XOR of the first operand with the inside of the
3707 negation of the second operand. */
3712 else
3735 {
3742 /* A COND_EXPR may have a throw as one operand, which
3743 then has void type. Just leave void operands
3744 as they are. */
3750 }
3762 CASE_CONVERT:
3766 /* fall through */
3788 }
3789 }
3791 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3792 assume that ARG is an operation that returns a truth value (0 or 1
3793 for scalars, 0 or -1 for vectors). Return the folded expression if
3794 folding is successful. Otherwise, return NULL_TREE. */
3796 static tree
3798 {
3801 ? BIT_NOT_EXPR
3804 }
3806 /* Return a simplified tree node for the truth-negation of ARG. This
3807 never alters ARG itself. We assume that ARG is an operation that
3808 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3810 tree
3812 {
3818 ? BIT_NOT_EXPR
3821 }
3823 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3824 with code CODE. This optimization is unsafe. */
3825 static tree
3828 {
3832 /* (A / C) +- (B / C) -> (A +- B) / C. */
3842 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3847 {
3859 }
3862 }
3863 \f
3864 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3865 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3866 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3867 is the original memory reference used to preserve the alias set of
3868 the access. */
3870 static tree
3874 {
3877 /* Attempt not to lose the access path if possible. */
3879 {
3881 machine_mode nmode;
3883 tree noffset;
3893 && !reversep
3894 && !nreversep
3896 {
3899 }
3900 }
3909 {
3916 }
3931 }
3933 /* Optimize a bit-field compare.
3935 There are two cases: First is a compare against a constant and the
3936 second is a comparison of two items where the fields are at the same
3937 bit position relative to the start of a chunk (byte, halfword, word)
3938 large enough to contain it. In these cases we can avoid the shift
3939 implicit in bitfield extractions.
3941 For constants, we emit a compare of the shifted constant with the
3942 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3943 compared. For two fields at the same position, we do the ANDs with the
3944 similar mask and compare the result of the ANDs.
3946 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3947 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3948 are the left and right operands of the comparison, respectively.
3950 If the optimization described above can be done, we return the resulting
3951 tree. Otherwise we return zero. */
3953 static tree
3956 {
3959 tree unsigned_type;
3966 tree mask;
3967 tree offset;
3969 /* Get all the information about the extractions being done. If the bit size
3970 if the same as the size of the underlying object, we aren't doing an
3971 extraction at all and so can do nothing. We also don't want to
3972 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3973 then will no longer be able to replace it. */
3982 else
3983 {
3984 /* If this is not a constant, we can only do something if bit positions,
3985 sizes, signedness and storage order are the same. */
3986 rinner
3994 }
3996 /* Honor the C++ memory model and mimic what RTL expansion does. */
4000 {
4004 }
4006 /* See if we can find a mode to refer to this field. We should be able to,
4007 but fail if we can't. */
4016 /* Set signed and unsigned types of the precision of this mode for the
4017 shifts below. */
4020 /* Compute the bit position and size for the new reference and our offset
4021 within it. If the new reference is the same size as the original, we
4022 won't optimize anything, so return zero. */
4032 /* Make the mask to be used against the extracted field. */
4039 /* If not comparing with constant, just rework the comparison
4040 and return. */
4044 unsigned_type,
4047 mask),
4050 unsigned_type,
4053 mask));
4055 /* Otherwise, we are handling the constant case. See if the constant is too
4056 big for the field. Warn and return a tree for 0 (false) if so. We do
4057 this not only for its own sake, but to avoid having to test for this
4058 error case below. If we didn't, we might generate wrong code.
4060 For unsigned fields, the constant shifted right by the field length should
4061 be all zero. For signed fields, the high-order bits should agree with
4062 the sign bit. */
4065 {
4067 {
4071 }
4072 }
4073 else
4074 {
4077 {
4081 }
4082 }
4084 /* Single-bit compares should always be against zero. */
4086 {
4089 }
4091 /* Make a new bitfield reference, shift the constant over the
4092 appropriate number of bits and mask it with the computed mask
4093 (in case this was a signed field). If we changed it, make a new one. */
4101 mask);
4106 }
4107 \f
4108 /* Subroutine for fold_truth_andor_1: decode a field reference.
4110 If EXP is a comparison reference, we return the innermost reference.
4112 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4113 set to the starting bit number.
4115 If the innermost field can be completely contained in a mode-sized
4116 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4118 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4119 otherwise it is not changed.
4121 *PUNSIGNEDP is set to the signedness of the field.
4123 *PREVERSEP is set to the storage order of the field.
4125 *PMASK is set to the mask used. This is either contained in a
4126 BIT_AND_EXPR or derived from the width of the field.
4128 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4130 Return 0 if this is not a component reference or is one that we can't
4131 do anything with. */
4133 static tree
4138 {
4143 tree unsigned_type;
4146 /* All the optimizations using this function assume integer fields.
4147 There are problems with FP fields since the type_for_size call
4148 below can fail for, e.g., XFmode. */
4152 /* We are interested in the bare arrangement of bits, so strip everything
4153 that doesn't affect the machine mode. However, record the type of the
4154 outermost expression if it may matter below. */
4161 {
4167 }
4174 /* Reject out-of-bound accesses (PR79731). */
4182 /* If the number of bits in the reference is the same as the bitsize of
4183 the outer type, then the outer type gives the signedness. Otherwise
4184 (in case of a small bitfield) the signedness is unchanged. */
4188 /* Compute the mask to access the bitfield. */
4197 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4205 }
4207 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4208 bit positions and MASK is SIGNED. */
4210 static int
4212 {
4216 /* If this function returns true when the type of the mask is
4217 UNSIGNED, then there will be errors. In particular see
4218 gcc.c-torture/execute/990326-1.c. There does not appear to be
4219 any documentation paper trail as to why this is so. But the pre
4220 wide-int worked with that restriction and it has been preserved
4221 here. */
4226 }
4228 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4229 represents the sign bit of EXP's type. If EXP represents a sign
4230 or zero extension, also test VAL against the unextended type.
4231 The return value is the (sub)expression whose sign bit is VAL,
4232 or NULL_TREE otherwise. */
4234 tree
4236 {
4238 tree t;
4240 /* Tree EXP must have an integral type. */
4245 /* Tree VAL must be an integer constant. */
4254 /* Handle extension from a narrower type. */
4260 }
4262 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4263 to be evaluated unconditionally. */
4265 static int
4267 {
4268 /* Strip any conversions that don't change the machine mode. */
4277 /* Don't regard global variables as simple. They may be
4278 allocated in ways unknown to the compiler (shared memory,
4279 #pragma weak, etc). */
4282 /* Weakrefs are not safe to be read, since they can be NULL.
4283 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4284 have DECL_WEAK flag set. */
4286 /* Loading a static variable is unduly expensive, but global
4287 registers aren't expensive. */
4289 }
4291 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4292 to be evaluated unconditionally.
4293 I addition to simple_operand_p, we assume that comparisons, conversions,
4294 and logic-not operations are simple, if their operands are simple, too. */
4296 static bool
4298 {
4318 }
4320 \f
4321 /* The following functions are subroutines to fold_range_test and allow it to
4322 try to change a logical combination of comparisons into a range test.
4324 For example, both
4325 X == 2 || X == 3 || X == 4 || X == 5
4326 and
4327 X >= 2 && X <= 5
4328 are converted to
4329 (unsigned) (X - 2) <= 3
4331 We describe each set of comparisons as being either inside or outside
4332 a range, using a variable named like IN_P, and then describe the
4333 range with a lower and upper bound. If one of the bounds is omitted,
4334 it represents either the highest or lowest value of the type.
4336 In the comments below, we represent a range by two numbers in brackets
4337 preceded by a "+" to designate being inside that range, or a "-" to
4338 designate being outside that range, so the condition can be inverted by
4339 flipping the prefix. An omitted bound is represented by a "-". For
4340 example, "- [-, 10]" means being outside the range starting at the lowest
4341 possible value and ending at 10, in other words, being greater than 10.
4342 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4343 always false.
4345 We set up things so that the missing bounds are handled in a consistent
4346 manner so neither a missing bound nor "true" and "false" need to be
4347 handled using a special case. */
4349 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4350 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4351 and UPPER1_P are nonzero if the respective argument is an upper bound
4352 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4353 must be specified for a comparison. ARG1 will be converted to ARG0's
4354 type if both are specified. */
4356 static tree
4359 {
4360 tree tem;
4364 /* If neither arg represents infinity, do the normal operation.
4365 Else, if not a comparison, return infinity. Else handle the special
4366 comparison rules. Note that most of the cases below won't occur, but
4367 are handled for consistency. */
4370 {
4375 }
4380 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4381 for neither. In real maths, we cannot assume open ended ranges are
4382 the same. But, this is computer arithmetic, where numbers are finite.
4383 We can therefore make the transformation of any unbounded range with
4384 the value Z, Z being greater than any representable number. This permits
4385 us to treat unbounded ranges as equal. */
4389 {
4410 }
4413 }
4414 \f
4415 /* Helper routine for make_range. Perform one step for it, return
4416 new expression if the loop should continue or NULL_TREE if it should
4417 stop. */
4419 tree
4423 {
4429 {
4431 /* We can only do something if the range is testing for zero. */
4440 /* We can only do something if the range is testing for zero
4441 and if the second operand is an integer constant. Note that
4442 saying something is "in" the range we make is done by
4443 complementing IN_P since it will set in the initial case of
4444 being not equal to zero; "out" is leaving it alone. */
4451 {
4472 }
4474 /* If this is an unsigned comparison, we also know that EXP is
4475 greater than or equal to zero. We base the range tests we make
4476 on that fact, so we record it here so we can parse existing
4477 range tests. We test arg0_type since often the return type
4478 of, e.g. EQ_EXPR, is boolean. */
4480 {
4484 NULL_TREE))
4489 /* If the high bound is missing, but we have a nonzero low
4490 bound, reverse the range so it goes from zero to the low bound
4491 minus 1. */
4493 {
4498 }
4499 }
4507 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4508 low and high are non-NULL, then normalize will DTRT. */
4511 {
4516 }
4518 /* (-x) IN [a,b] -> x in [-b, -a] */
4530 /* ~ X -> -X - 1 */
4539 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4540 move a constant to the other side. */
4545 /* If EXP is signed, any overflow in the computation is undefined,
4546 so we don't worry about it so long as our computations on
4547 the bounds don't overflow. For unsigned, overflow is defined
4548 and this is exactly the right thing. */
4560 normalize:
4561 /* Check for an unsigned range which has wrapped around the maximum
4562 value thus making n_high < n_low, and normalize it. */
4564 {
4570 /* If the range is of the form +/- [ x+1, x ], we won't
4571 be able to normalize it. But then, it represents the
4572 whole range or the empty set, so make it
4573 +/- [ -, - ]. */
4577 else
4579 }
4580 else
4588 CASE_CONVERT:
4606 /* If we're converting arg0 from an unsigned type, to exp,
4607 a signed type, we will be doing the comparison as unsigned.
4608 The tests above have already verified that LOW and HIGH
4609 are both positive.
4611 So we have to ensure that we will handle large unsigned
4612 values the same way that the current signed bounds treat
4613 negative values. */
4616 {
4617 tree high_positive;
4618 tree equiv_type;
4619 /* For fixed-point modes, we need to pass the saturating flag
4620 as the 2nd parameter. */
4622 equiv_type
4625 else
4626 equiv_type
4629 /* A range without an upper bound is, naturally, unbounded.
4630 Since convert would have cropped a very large value, use
4631 the max value for the destination type. */
4632 high_positive
4639 high_positive),
4642 /* If the low bound is specified, "and" the range with the
4643 range for which the original unsigned value will be
4644 positive. */
4646 {
4649 integer_zero_node),
4650 high_positive))
4654 }
4655 else
4656 {
4657 /* Otherwise, "or" the range with the range of the input
4658 that will be interpreted as negative. */
4661 integer_zero_node),
4662 high_positive))
4666 }
4667 }
4676 }
4677 }
4679 /* Given EXP, a logical expression, set the range it is testing into
4680 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4681 actually being tested. *PLOW and *PHIGH will be made of the same
4682 type as the returned expression. If EXP is not a comparison, we
4683 will most likely not be returning a useful value and range. Set
4684 *STRICT_OVERFLOW_P to true if the return value is only valid
4685 because signed overflow is undefined; otherwise, do not change
4686 *STRICT_OVERFLOW_P. */
4688 tree
4691 {
4699 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4700 and see if we can refine the range. Some of the cases below may not
4701 happen, but it doesn't seem worth worrying about this. We "continue"
4702 the outer loop when we've changed something; otherwise we "break"
4703 the switch, which will "break" the while. */
4709 {
4715 {
4723 }
4732 }
4734 /* If EXP is a constant, we can evaluate whether this is true or false. */
4736 {
4743 }
4747 }
4748 \f
4749 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4750 type, TYPE, return an expression to test if EXP is in (or out of, depending
4751 on IN_P) the range. Return 0 if the test couldn't be created. */
4753 tree
4756 {
4759 /* Disable this optimization for function pointer expressions
4760 on targets that require function pointer canonicalization. */
4767 {
4773 }
4791 {
4793 {
4797 }
4799 }
4801 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4803 {
4807 {
4809 {
4812 etype
4814 else
4817 }
4820 }
4821 }
4823 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4824 This requires wrap-around arithmetics for the type of the expression.
4825 First make sure that arithmetics in this type is valid, then make sure
4826 that it wraps around. */
4832 {
4835 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4836 for the type in question, as we rely on this here. */
4846 else
4848 }
4858 {
4860 {
4865 }
4867 }
4875 }
4876 \f
4877 /* Return the predecessor of VAL in its type, handling the infinite case. */
4879 static tree
4881 {
4887 else
4890 }
4892 /* Return the successor of VAL in its type, handling the infinite case. */
4894 static tree
4896 {
4902 else
4905 }
4907 /* Given two ranges, see if we can merge them into one. Return 1 if we
4908 can, 0 if we can't. Set the output range into the specified parameters. */
4910 bool
4913 {
4917 tree tem;
4927 /* Make range 0 be the range that starts first, or ends last if they
4928 start at the same value. Swap them if it isn't. */
4931 || (lowequal
4934 {
4938 }
4940 /* Now flag two cases, whether the ranges are disjoint or whether the
4941 second range is totally subsumed in the first. Note that the tests
4942 below are simplified by the ones above. */
4948 /* We now have four cases, depending on whether we are including or
4949 excluding the two ranges. */
4951 {
4952 /* If they don't overlap, the result is false. If the second range
4953 is a subset it is the result. Otherwise, the range is from the start
4954 of the second to the end of the first. */
4959 else
4961 }
4964 {
4965 /* If they don't overlap, the result is the first range. If they are
4966 equal, the result is false. If the second range is a subset of the
4967 first, and the ranges begin at the same place, we go from just after
4968 the end of the second range to the end of the first. If the second
4969 range is not a subset of the first, or if it is a subset and both
4970 ranges end at the same place, the range starts at the start of the
4971 first range and ends just before the second range.
4972 Otherwise, we can't describe this as a single range. */
4978 {
4983 {
4984 /* We are in the weird situation where high0 > high1 but
4985 high1 has no successor. Punt. */
4987 }
4988 }
4990 {
4995 {
4996 /* low0 < low1 but low1 has no predecessor. Punt. */
4998 }
4999 }
5000 else
5002 }
5005 {
5006 /* If they don't overlap, the result is the second range. If the second
5007 is a subset of the first, the result is false. Otherwise,
5008 the range starts just after the first range and ends at the
5009 end of the second. */
5014 else
5015 {
5020 {
5021 /* high1 > high0 but high0 has no successor. Punt. */
5023 }
5024 }
5025 }
5027 else
5028 {
5029 /* The case where we are excluding both ranges. Here the complex case
5030 is if they don't overlap. In that case, the only time we have a
5031 range is if they are adjacent. If the second is a subset of the
5032 first, the result is the first. Otherwise, the range to exclude
5033 starts at the beginning of the first range and ends at the end of the
5034 second. */
5036 {
5041 else
5042 {
5043 /* Canonicalize - [min, x] into - [-, x]. */
5046 {
5051 /* FALLTHROUGH */
5064 }
5066 /* Canonicalize - [x, max] into - [x, -]. */
5069 {
5074 /* FALLTHROUGH */
5090 }
5092 /* The ranges might be also adjacent between the maximum and
5093 minimum values of the given type. For
5094 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5095 return + [x + 1, y - 1]. */
5097 {
5104 }
5105 else
5107 }
5108 }
5111 else
5113 }
5117 }
5118 \f
5120 /* Subroutine of fold, looking inside expressions of the form
5121 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5122 of the COND_EXPR. This function is being used also to optimize
5123 A op B ? C : A, by reversing the comparison first.
5125 Return a folded expression whose code is not a COND_EXPR
5126 anymore, or NULL_TREE if no folding opportunity is found. */
5128 static tree
5131 {
5136 tree tem;
5141 /* If we have A op 0 ? A : -A, consider applying the following
5142 transformations:
5144 A == 0? A : -A same as -A
5145 A != 0? A : -A same as A
5146 A >= 0? A : -A same as abs (A)
5147 A > 0? A : -A same as abs (A)
5148 A <= 0? A : -A same as -abs (A)
5149 A < 0? A : -A same as -abs (A)
5151 None of these transformations work for modes with signed
5152 zeros. If A is +/-0, the first two transformations will
5153 change the sign of the result (from +0 to -0, or vice
5154 versa). The last four will fix the sign of the result,
5155 even though the original expressions could be positive or
5156 negative, depending on the sign of A.
5158 Note that all these transformations are correct if A is
5159 NaN, since the two alternatives (A and -A) are also NaNs. */
5166 /* In the case that A is of the form X-Y, '-A' (arg2) may
5167 have already been folded to Y-X, check for that. */
5175 {
5187 /* Fall through. */
5198 /* FALLTHRU */
5208 }
5210 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5211 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5212 both transformations are correct when A is NaN: A != 0
5213 is then true, and A == 0 is false. */
5217 {
5222 }
5224 /* Try some transformations of A op B ? A : B.
5226 A == B? A : B same as B
5227 A != B? A : B same as A
5228 A >= B? A : B same as max (A, B)
5229 A > B? A : B same as max (B, A)
5230 A <= B? A : B same as min (A, B)
5231 A < B? A : B same as min (B, A)
5233 As above, these transformations don't work in the presence
5234 of signed zeros. For example, if A and B are zeros of
5235 opposite sign, the first two transformations will change
5236 the sign of the result. In the last four, the original
5237 expressions give different results for (A=+0, B=-0) and
5238 (A=-0, B=+0), but the transformed expressions do not.
5240 The first two transformations are correct if either A or B
5241 is a NaN. In the first transformation, the condition will
5242 be false, and B will indeed be chosen. In the case of the
5243 second transformation, the condition A != B will be true,
5244 and A will be chosen.
5246 The conversions to max() and min() are not correct if B is
5247 a number and A is not. The conditions in the original
5248 expressions will be false, so all four give B. The min()
5249 and max() versions would give a NaN instead. */
5252 /* Avoid these transformations if the COND_EXPR may be used
5253 as an lvalue in the C++ front-end. PR c++/19199. */
5254 && (in_gimple_form
5260 {
5266 {
5275 /* In C++ a ?: expression can be an lvalue, so put the
5276 operand which will be used if they are equal first
5277 so that we can convert this back to the
5278 corresponding COND_EXPR. */
5280 {
5288 }
5295 {
5303 }
5316 }
5317 }
5320 }
5323 \f
5324 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5325 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5326 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5327 false) >= 2)
5328 #endif
5330 /* EXP is some logical combination of boolean tests. See if we can
5331 merge it into some range test. Return the new tree if so. */
5333 static tree
5336 {
5352 /* If this is an OR operation, invert both sides; we will invert
5353 again at the end. */
5357 /* If both expressions are the same, if we can merge the ranges, and we
5358 can build the range test, return it or it inverted. If one of the
5359 ranges is always true or always false, consider it to be the same
5360 expression as the other. */
5368 {
5372 }
5374 /* On machines where the branch cost is expensive, if this is a
5375 short-circuited branch and the underlying object on both sides
5376 is the same, make a non-short-circuit operation. */
5382 {
5383 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5384 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5385 which cases we can't do this. */
5393 {
5402 {
5405 WARN_STRICT_OVERFLOW_COMPARISON);
5409 }
5410 }
5411 }
5414 }
5415 \f
5416 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5417 bit value. Arrange things so the extra bits will be set to zero if and
5418 only if C is signed-extended to its full width. If MASK is nonzero,
5419 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5421 static tree
5423 {
5426 tree temp;
5431 /* We work by getting just the sign bit into the low-order bit, then
5432 into the high-order bit, then sign-extend. We then XOR that value
5433 with C. */
5436 /* We must use a signed type in order to get an arithmetic right shift.
5437 However, we must also avoid introducing accidental overflows, so that
5438 a subsequent call to integer_zerop will work. Hence we must
5439 do the type conversion here. At this point, the constant is either
5440 zero or one, and the conversion to a signed type can never overflow.
5441 We could get an overflow if this conversion is done anywhere else. */
5450 /* If necessary, convert the type back to match the type of C. */
5455 }
5456 \f
5457 /* For an expression that has the form
5458 (A && B) || ~B
5459 or
5460 (A || B) && ~B,
5461 we can drop one of the inner expressions and simplify to
5462 A || ~B
5463 or
5464 A && ~B
5465 LOC is the location of the resulting expression. OP is the inner
5466 logical operation; the left-hand side in the examples above, while CMPOP
5467 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5468 removing a condition that guards another, as in
5469 (A != NULL && A->...) || A == NULL
5470 which we must not transform. If RHS_ONLY is true, only eliminate the
5471 right-most operand of the inner logical operation. */
5473 static tree
5476 {
5494 {
5497 {
5500 }
5501 }
5503 {
5506 {
5509 }
5510 }
5525 }
5527 /* Find ways of folding logical expressions of LHS and RHS:
5528 Try to merge two comparisons to the same innermost item.
5529 Look for range tests like "ch >= '0' && ch <= '9'".
5530 Look for combinations of simple terms on machines with expensive branches
5531 and evaluate the RHS unconditionally.
5533 For example, if we have p->a == 2 && p->b == 4 and we can make an
5534 object large enough to span both A and B, we can do this with a comparison
5535 against the object ANDed with the a mask.
5537 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5538 operations to do this with one comparison.
5540 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5541 function and the one above.
5543 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5544 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5546 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5547 two operands.
5549 We return the simplified tree or 0 if no optimization is possible. */
5551 static tree
5554 {
5555 /* If this is the "or" of two comparisons, we can do something if
5556 the comparisons are NE_EXPR. If this is the "and", we can do something
5557 if the comparisons are EQ_EXPR. I.e.,
5558 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5560 WANTED_CODE is this operation code. For single bit fields, we can
5561 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5562 comparison for one-bit fields. */
5583 /* Start by getting the comparison codes. Fail if anything is volatile.
5584 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5585 it were surrounded with a NE_EXPR. */
5594 {
5598 }
5601 {
5605 }
5616 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5619 {
5622 {
5627 }
5630 {
5636 }
5637 }
5642 /* If the RHS can be evaluated unconditionally and its operands are
5643 simple, it wins to evaluate the RHS unconditionally on machines
5644 with expensive branches. In this case, this isn't a comparison
5645 that can be merged. */
5652 {
5653 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5664 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5674 }
5676 /* See if the comparisons can be merged. Then get all the parameters for
5677 each side. */
5702 /* It must be true that the inner operation on the lhs of each
5703 comparison must be the same if we are to be able to do anything.
5704 Then see if we have constants. If not, the same must be true for
5705 the rhs's. */
5714 {
5717 }
5722 else
5725 /* If either comparison code is not correct for our logical operation,
5726 fail. However, we can convert a one-bit comparison against zero into
5727 the opposite comparison against that bit being set in the field. */
5731 {
5733 {
5734 /* Make the left operand unsigned, since we are only interested
5735 in the value of one bit. Otherwise we are doing the wrong
5736 thing below. */
5739 }
5740 else
5742 }
5744 /* This is analogous to the code for l_const above. */
5746 {
5748 {
5751 }
5752 else
5754 }
5756 /* See if we can find a mode that contains both fields being compared on
5757 the left. If we can't, fail. Otherwise, update all constants and masks
5758 to be relative to a field of that size. */
5763 volatilep);
5773 {
5776 }
5784 {
5791 {
5795 }
5796 }
5798 {
5805 {
5809 }
5810 }
5812 /* If the right sides are not constant, do the same for it. Also,
5813 disallow this optimization if a size or signedness mismatch occurs
5814 between the left and right sides. */
5816 {
5819 /* Make sure the two fields on the right
5820 correspond to the left without being swapped. */
5828 volatilep);
5838 {
5841 }
5850 /* Make a mask that corresponds to both fields being compared.
5851 Do this for both items being compared. If the operands are the
5852 same size and the bits being compared are in the same position
5853 then we can do this by masking both and comparing the masked
5854 results. */
5858 {
5872 }
5874 /* There is still another way we can do something: If both pairs of
5875 fields being compared are adjacent, we may be able to make a wider
5876 field containing them both.
5878 Note that we still must mask the lhs/rhs expressions. Furthermore,
5879 the mask must be shifted to account for the shift done by
5880 make_bit_field_ref. */
5885 {
5886 tree type;
5902 /* Convert to the smaller type before masking out unwanted bits. */
5905 {
5907 {
5911 }
5913 {
5917 }
5918 }
5927 }
5930 }
5932 /* Handle the case of comparisons with constants. If there is something in
5933 common between the masks, those bits of the constants must be the same.
5934 If not, the condition is always false. Test for this to avoid generating
5935 incorrect code below. */
5940 {
5942 {
5945 }
5946 else
5947 {
5950 }
5951 }
5953 /* Construct the expression we will return. First get the component
5954 reference we will make. Unless the mask is all ones the width of
5955 that field, perform the mask operation. Then compare with the
5956 merged constant. */
5967 }
5968 \f
5969 /* T is an integer expression that is being multiplied, divided, or taken a
5970 modulus (CODE says which and what kind of divide or modulus) by a
5971 constant C. See if we can eliminate that operation by folding it with
5972 other operations already in T. WIDE_TYPE, if non-null, is a type that
5973 should be used for the computation if wider than our type.
5975 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5976 (X * 2) + (Y * 4). We must, however, be assured that either the original
5977 expression would not overflow or that overflow is undefined for the type
5978 in the language in question.
5980 If we return a non-null expression, it is an equivalent form of the
5981 original computation, but need not be in the original type.
5983 We set *STRICT_OVERFLOW_P to true if the return values depends on
5984 signed overflow being undefined. Otherwise we do not change
5985 *STRICT_OVERFLOW_P. */
5987 static tree
5990 {
5991 /* To avoid exponential search depth, refuse to allow recursion past
5992 three levels. Beyond that (1) it's highly unlikely that we'll find
5993 something interesting and (2) we've probably processed it before
5994 when we built the inner expression. */
5997 tree ret;
6002 depth++;
6004 depth--;
6007 }
6009 static tree
6012 {
6023 /* Don't deal with constants of zero here; they confuse the code below. */
6033 /* Note that we need not handle conditional operations here since fold
6034 already handles those cases. So just do arithmetic here. */
6036 {
6038 /* For a constant, we can always simplify if we are a multiply
6039 or (for divide and modulus) if it is a multiple of our constant. */
6042 {
6045 /* If the multiplication overflowed, we lost information on it.
6046 See PR68142 and PR69845. */
6050 }
6054 /* If op0 is an expression ... */
6060 /* ... and has wrapping overflow, and its type is smaller
6061 than ctype, then we cannot pass through as widening. */
6066 /* ... or this is a truncation (t is narrower than op0),
6067 then we cannot pass through this narrowing. */
6070 /* ... or signedness changes for division or modulus,
6071 then we cannot pass through this conversion. */
6075 /* ... or has undefined overflow while the converted to
6076 type has not, we cannot do the operation in the inner type
6077 as that would introduce undefined overflow. */
6083 /* Pass the constant down and see if we can make a simplification. If
6084 we can, replace this expression with the inner simplification for
6085 possible later conversion to our or some other type. */
6090 code == MULT_EXPR
6092 strict_overflow_p))))
6097 /* If widening the type changes it from signed to unsigned, then we
6098 must avoid building ABS_EXPR itself as unsigned. */
6100 {
6104 {
6107 }
6109 }
6110 /* If the constant is negative, we cannot simplify this. */
6113 /* FALLTHROUGH */
6115 /* For division and modulus, type can't be unsigned, as e.g.
6116 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6117 For signed types, even with wrapping overflow, this is fine. */
6126 /* If widening the type changes the signedness, then we can't perform
6127 this optimization as that changes the result. */
6131 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6137 {
6144 }
6148 /* If the second operand is constant, this is a multiplication
6149 or floor division, by a power of two, so we can treat it that
6150 way unless the multiplier or divisor overflows. Signed
6151 left-shift overflow is implementation-defined rather than
6152 undefined in C90, so do not convert signed left shift into
6153 multiplication. */
6156 /* const_binop may not detect overflow correctly,
6157 so check for it explicitly here. */
6161 size_one_node,
6162 op1)))
6166 ctype,
6168 t1),
6173 /* See if we can eliminate the operation on both sides. If we can, we
6174 can return a new PLUS or MINUS. If we can't, the only remaining
6175 cases where we can do anything are if the second operand is a
6176 constant. */
6182 /* If not multiplication, we can only do this if both operands
6183 are divisible by c. */
6186 {
6191 }
6193 /* If this was a subtraction, negate OP1 and set it to be an addition.
6194 This simplifies the logic below. */
6196 {
6198 /* If OP1 was not easily negatable, the constant may be OP0. */
6200 {
6203 }
6204 }
6209 /* If either OP1 or C are negative, this optimization is not safe for
6210 some of the division and remainder types while for others we need
6211 to change the code. */
6213 {
6221 }
6223 /* If it's a multiply or a division/modulus operation of a multiple
6224 of our constant, do the operation and verify it doesn't overflow. */
6227 {
6230 /* We allow the constant to overflow with wrapping semantics. */
6234 }
6235 else
6238 /* If we have an unsigned type, we cannot widen the operation since it
6239 will change the result if the original computation overflowed. */
6243 /* If we were able to eliminate our operation from the first side,
6244 apply our operation to the second side and reform the PLUS. */
6248 /* The last case is if we are a multiply. In that case, we can
6249 apply the distributive law to commute the multiply and addition
6250 if the multiplication of the constants doesn't overflow
6251 and overflow is defined. With undefined overflow
6252 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6258 op1);
6263 /* We have a special case here if we are doing something like
6264 (C * 8) % 4 since we know that's zero. */
6267 /* If the multiplication can overflow we cannot optimize this. */
6271 {
6274 }
6276 /* ... fall through ... */
6280 /* If we can extract our operation from the LHS, do so and return a
6281 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6282 do something only if the second operand is a constant. */
6298 /* If these are the same operation types, we can associate them
6299 assuming no overflow. */
6301 {
6316 }
6318 /* If these operations "cancel" each other, we have the main
6319 optimizations of this pass, which occur when either constant is a
6320 multiple of the other, in which case we replace this with either an
6321 operation or CODE or TCODE.
6323 If we have an unsigned type, we cannot do this since it will change
6324 the result if the original computation overflowed. */
6331 {
6333 {
6340 }
6342 {
6349 }
6350 }
6355 }
6358 }
6359 \f
6360 /* Return a node which has the indicated constant VALUE (either 0 or
6361 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6362 and is of the indicated TYPE. */
6364 tree
6366 {
6375 else
6377 }
6380 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6381 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6382 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6383 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6384 COND is the first argument to CODE; otherwise (as in the example
6385 given here), it is the second argument. TYPE is the type of the
6386 original expression. Return NULL_TREE if no simplification is
6387 possible. */
6389 static tree
6394 {
6404 {
6408 /* If this operand throws an expression, then it does not make
6409 sense to try to perform a logical or arithmetic operation
6410 involving it. */
6415 }
6418 {
6423 }
6424 else
6425 /* Detect the case of mixing vector and scalar types - bail out. */
6431 /* This transformation is only worthwhile if we don't have to wrap ARG
6432 in a SAVE_EXPR and the operation can be simplified without recursing
6433 on at least one of the branches once its pushed inside the COND_EXPR. */
6442 {
6446 else
6448 }
6450 {
6454 else
6456 }
6458 /* Check that we have simplified at least one of the branches. */
6463 }
6465 \f
6466 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6468 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6469 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6470 ADDEND is the same as X.
6472 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6473 and finite. The problematic cases are when X is zero, and its mode
6474 has signed zeros. In the case of rounding towards -infinity,
6475 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6476 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6478 bool
6480 {
6484 /* Don't allow the fold with -fsignaling-nans. */
6488 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6492 /* In a vector or complex, we would need to check the sign of all zeros. */
6496 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6500 /* The mode has signed zeros, and we have to honor their sign.
6501 In this situation, there is only one case we can return true for.
6502 X - 0 is the same as X unless rounding towards -infinity is
6503 supported. */
6505 }
6507 /* Subroutine of fold() that optimizes comparisons of a division by
6508 a nonzero integer constant against an integer constant, i.e.
6509 X/C1 op C2.
6511 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6512 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6513 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6515 The function returns the constant folded tree if a simplification
6516 can be made, and NULL_TREE otherwise. */
6518 static tree
6521 {
6529 /* We have to do this the hard way to detect unsigned overflow.
6530 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6536 {
6541 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6545 }
6547 {
6551 {
6570 }
6571 }
6572 else
6573 {
6574 /* A negative divisor reverses the relational operators. */
6580 {
6599 }
6600 }
6603 {
6624 {
6627 }
6632 {
6635 }
6640 {
6643 }
6648 {
6651 }
6656 }
6659 }
6662 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6663 equality/inequality test, then return a simplified form of the test
6664 using a sign testing. Otherwise return NULL. TYPE is the desired
6665 result type. */
6667 static tree
6670 tree result_type)
6671 {
6672 /* If this is testing a single bit, we can optimize the test. */
6676 {
6677 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6678 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6682 /* This is only a win if casting to a signed type is cheap,
6683 i.e. when arg00's type is not a partial mode. */
6686 {
6689 result_type,
6692 }
6693 }
6696 }
6698 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6699 equality/inequality test, then return a simplified form of
6700 the test using shifts and logical operations. Otherwise return
6701 NULL. TYPE is the desired result type. */
6703 tree
6706 {
6707 /* If this is testing a single bit, we can optimize the test. */
6711 {
6720 /* First, see if we can fold the single bit test into a sign-bit
6721 test. */
6723 result_type);
6727 /* Otherwise we have (A & C) != 0 where C is a single bit,
6728 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6729 Similarly for (A & C) == 0. */
6731 /* If INNER is a right shift of a constant and it plus BITNUM does
6732 not overflow, adjust BITNUM and INNER. */
6738 {
6741 }
6743 /* If we are going to be able to omit the AND below, we must do our
6744 operations as unsigned. If we must use the AND, we have a choice.
6745 Normally unsigned is faster, but for some machines signed is. */
6763 /* Put the AND last so it can combine with more things. */
6766 /* Make sure to return the proper type. */
6770 }
6772 }
6774 /* Test whether it is preferable two swap two operands, ARG0 and
6775 ARG1, for example because ARG0 is an integer constant and ARG1
6776 isn't. */
6778 bool
6780 {
6794 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6795 for commutative and comparison operators. Ensuring a canonical
6796 form allows the optimizers to find additional redundancies without
6797 having to explicitly check for both orderings. */
6803 /* Put SSA_NAMEs last. */
6809 /* Put variables last. */
6816 }
6819 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6820 means A >= Y && A != MAX, but in this case we know that
6821 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6823 static tree
6825 {
6832 else
6841 {
6844 }
6846 {
6849 }
6850 else
6857 {
6858 /* Convert the pointer types into integer before taking the difference. */
6862 }
6863 else
6870 }
6872 /* Fold a sum or difference of at least one multiplication.
6873 Returns the folded tree or NULL if no simplification could be made. */
6875 static tree
6878 {
6882 /* (A * C) +- (B * C) -> (A+-B) * C.
6883 (A * C) +- A -> A * (C+-1).
6884 We are most concerned about the case where C is a constant,
6885 but other combinations show up during loop reduction. Since
6886 it is not difficult, try all four possibilities. */
6889 {
6892 }
6894 {
6897 }
6898 else
6899 {
6900 /* We cannot generate constant 1 for fract. */
6905 }
6907 {
6910 }
6912 {
6914 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6915 the purpose of this canonicalization. */
6919 {
6922 }
6923 else
6925 }
6926 else
6927 {
6928 /* We cannot generate constant 1 for fract. */
6933 }
6945 /* No identical multiplicands; see if we can find a common
6946 power-of-two factor in non-power-of-two multiplies. This
6947 can help in multi-dimensional array access. */
6950 {
6953 tree maybe_same;
6957 /* Move min of absolute values to int11. */
6959 {
6964 }
6965 else
6969 /* The remainder should not be a constant, otherwise we
6970 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6971 increased the number of multiplications necessary. */
6973 {
6981 }
6982 }
6992 }
6994 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6995 specified by EXPR into the buffer PTR of length LEN bytes.
6996 Return the number of bytes placed in the buffer, or zero
6997 upon failure. */
6999 static int
7001 {
7015 {
7017 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7018 number of bytes. */
7022 {
7029 else
7031 }
7032 else
7037 }
7039 }
7042 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7043 specified by EXPR into the buffer PTR of length LEN bytes.
7044 Return the number of bytes placed in the buffer, or zero
7045 upon failure. */
7047 static int
7049 {
7053 FIXED_VALUE_TYPE value;
7069 }
7072 /* Subroutine of native_encode_expr. Encode the REAL_CST
7073 specified by EXPR into the buffer PTR of length LEN bytes.
7074 Return the number of bytes placed in the buffer, or zero
7075 upon failure. */
7077 static int
7079 {
7085 /* There are always 32 bits in each long, no matter the size of
7086 the hosts long. We handle floating point representations with
7087 up to 192 bits. */
7101 {
7106 {
7113 else
7115 }
7116 else
7117 {
7120 {
7121 /* Reverse bytes within each long, or within the entire float
7122 if it's smaller than a long (for HFmode). */
7125 }
7126 }
7131 }
7133 }
7135 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7136 specified by EXPR into the buffer PTR of length LEN bytes.
7137 Return the number of bytes placed in the buffer, or zero
7138 upon failure. */
7140 static int
7142 {
7144 tree part;
7159 }
7162 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7163 specified by EXPR into the buffer PTR of length LEN bytes.
7164 Return the number of bytes placed in the buffer, or zero
7165 upon failure. */
7167 static int
7169 {
7179 {
7181 {
7184 }
7195 }
7197 }
7200 /* Subroutine of native_encode_expr. Encode the STRING_CST
7201 specified by EXPR into the buffer PTR of length LEN bytes.
7202 Return the number of bytes placed in the buffer, or zero
7203 upon failure. */
7205 static int
7207 {
7209 HOST_WIDE_INT total_bytes;
7223 {
7226 {
7229 }
7232 }
7233 else
7236 }
7239 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7240 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7241 buffer PTR of length LEN bytes. If OFF is not -1 then start
7242 the encoding at byte offset OFF and encode at most LEN bytes.
7243 Return the number of bytes placed in the buffer, or zero upon failure. */
7245 int
7247 {
7248 /* We don't support starting at negative offset and -1 is special. */
7253 {
7274 }
7275 }
7278 /* Subroutine of native_interpret_expr. Interpret the contents of
7279 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7280 If the buffer cannot be interpreted, return NULL_TREE. */
7282 static tree
7284 {
7294 }
7297 /* Subroutine of native_interpret_expr. Interpret the contents of
7298 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7299 If the buffer cannot be interpreted, return NULL_TREE. */
7301 static tree
7303 {
7305 double_int result;
7306 FIXED_VALUE_TYPE fixed_value;
7316 }
7319 /* Subroutine of native_interpret_expr. Interpret the contents of
7320 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7321 If the buffer cannot be interpreted, return NULL_TREE. */
7323 static tree
7325 {
7329 /* There are always 32 bits in each long, no matter the size of
7330 the hosts long. We handle floating point representations with
7331 up to 192 bits. */
7332 REAL_VALUE_TYPE r;
7343 {
7344 /* Both OFFSET and BYTE index within a long;
7345 bitpos indexes the whole float. */
7348 {
7355 else
7357 }
7358 else
7359 {
7362 {
7363 /* Reverse bytes within each long, or within the entire float
7364 if it's smaller than a long (for HFmode). */
7367 }
7368 }
7372 }
7376 }
7379 /* Subroutine of native_interpret_expr. Interpret the contents of
7380 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7381 If the buffer cannot be interpreted, return NULL_TREE. */
7383 static tree
7385 {
7400 }
7403 /* Subroutine of native_interpret_expr. Interpret the contents of
7404 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7405 If the buffer cannot be interpreted, return NULL_TREE. */
7407 static tree
7409 {
7422 {
7427 }
7429 }
7432 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7433 the buffer PTR of length LEN as a constant of type TYPE. For
7434 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7435 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7436 return NULL_TREE. */
7438 tree
7440 {
7442 {
7464 }
7465 }
7467 /* Returns true if we can interpret the contents of a native encoding
7468 as TYPE. */
7470 static bool
7472 {
7474 {
7487 }
7488 }
7490 /* Return true iff a constant of type TYPE is accepted by
7491 native_encode_expr. */
7493 bool
7495 {
7497 {
7507 }
7508 }
7510 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7511 TYPE at compile-time. If we're unable to perform the conversion
7512 return NULL_TREE. */
7514 static tree
7516 {
7517 /* We support up to 512-bit values (for V8DFmode). */
7521 /* Check that the host and target are sane. */
7530 }
7532 /* Build an expression for the address of T. Folds away INDIRECT_REF
7533 to avoid confusing the gimplify process. */
7535 tree
7537 {
7538 /* The size of the object is not relevant when talking about its address. */
7543 {
7548 }
7558 {
7563 }
7564 else
7568 }
7570 /* Build an expression for the address of T. */
7572 tree
7574 {
7578 }
7580 /* Fold a unary expression of code CODE and type TYPE with operand
7581 OP0. Return the folded expression if folding is successful.
7582 Otherwise, return NULL_TREE. */
7584 tree
7586 {
7587 tree tem;
7588 tree arg0;
7596 {
7599 {
7600 /* Don't use STRIP_NOPS, because signedness of argument type
7601 matters. */
7603 }
7604 else
7605 {
7606 /* Strip any conversions that don't change the mode. This
7607 is safe for every expression, except for a comparison
7608 expression because its signedness is derived from its
7609 operands.
7611 Note that this is done as an internal manipulation within
7612 the constant folder, in order to find the simplest
7613 representation of the arguments so that their form can be
7614 studied. In any cases, the appropriate type conversions
7615 should be put back in the tree that will get out of the
7616 constant folder. */
7618 }
7621 {
7624 {
7628 }
7629 }
7630 }
7637 {
7644 {
7658 /* If this was a conversion, and all we did was to move into
7659 inside the COND_EXPR, bring it back out. But leave it if
7660 it is a conversion from integer to integer and the
7661 result precision is no wider than a word since such a
7662 conversion is cheap and may be optimized away by combine,
7663 while it couldn't if it were outside the COND_EXPR. Then return
7664 so we don't get into an infinite recursion loop taking the
7665 conversion out and then back in. */
7677 && (INTEGRAL_TYPE_P
7690 }
7691 }
7694 {
7700 CASE_CONVERT:
7704 {
7705 /* If we have (type) (a CMP b) and type is an integral type, return
7706 new expression involving the new type. Canonicalize
7707 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7708 non-integral type.
7709 Do not fold the result as that would not simplify further, also
7710 folding again results in recursions. */
7720 }
7722 /* Handle (T *)&A.B.C for A being of type T and B and C
7723 living at offset zero. This occurs frequently in
7724 C++ upcasting and then accessing the base. */
7728 {
7730 tree offset;
7731 machine_mode mode;
7733 tree base
7737 /* If the reference was to a (constant) zero offset, we can use
7738 the address of the base if it has the same base type
7739 as the result type and the pointer type is unqualified. */
7746 }
7750 /* Detect assigning a bitfield. */
7752 && DECL_BIT_FIELD
7754 {
7755 /* Don't leave an assignment inside a conversion
7756 unless assigning a bitfield. */
7758 /* First do the assignment, then return converted constant. */
7763 }
7765 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7766 constants (if x has signed type, the sign bit cannot be set
7767 in c). This folds extension into the BIT_AND_EXPR.
7768 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7769 very likely don't have maximal range for their precision and this
7770 transformation effectively doesn't preserve non-maximal ranges. */
7774 {
7785 <= HOST_BITS_PER_WIDE_INT
7787 {
7791 cst &= HOST_WIDE_INT_M1U
7795 && !flag_syntax_only
7798 {
7802 }
7803 }
7805 {
7810 }
7811 }
7813 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7814 cast (T1)X will fold away. We assume that this happens when X itself
7815 is a cast. */
7819 {
7823 return fold_build_pointer_plus_loc
7825 }
7827 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7828 of the same precision, and X is an integer type not narrower than
7829 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7835 {
7841 }
7843 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7844 type of X and Y (integer types only). */
7849 {
7850 /* Be careful not to introduce new overflows. */
7851 tree mult_type;
7854 else
7858 {
7865 }
7866 }
7872 {
7879 }
7890 /* Convert fabs((double)float) into (double)fabsf(float). */
7893 {
7899 targ0));
7900 }
7904 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7923 /* Note that the operand of this must be an int
7924 and its values must be 0 or 1.
7925 ("true" is a fixed value perhaps depending on the language,
7926 but we don't handle values other than 1 correctly yet.) */
7933 /* Fold *&X to X if X is an lvalue. */
7935 {
7942 }
7948 }
7951 /* If the operation was a conversion do _not_ mark a resulting constant
7952 with TREE_OVERFLOW if the original constant was not. These conversions
7953 have implementation defined behavior and retaining the TREE_OVERFLOW
7954 flag here would confuse later passes such as VRP. */
7955 tree
7958 {
7967 }
7969 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7970 operands OP0 and OP1. LOC is the location of the resulting expression.
7971 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7972 Return the folded expression if folding is successful. Otherwise,
7973 return NULL_TREE. */
7974 static tree
7977 {
7978 tree tem;
7980 /* We only do these simplifications if we are optimizing. */
7984 /* Check for things like (A || B) && (A || C). We can convert this
7985 to A || (B && C). Note that either operator can be any of the four
7986 truth and/or operations and the transformation will still be
7987 valid. Also note that we only care about order for the
7988 ANDIF and ORIF operators. If B contains side effects, this
7989 might change the truth-value of A. */
7996 {
8016 /* This case if tricky because we must either have commutative
8017 operators or else A10 must not have side-effects. */
8023 a01);
8024 }
8026 /* See if we can build a range comparison. */
8032 {
8036 }
8040 {
8044 }
8046 /* Check for the possibility of merging component references. If our
8047 lhs is another similar operation, try to merge its rhs with our
8048 rhs. Then try to merge our lhs and rhs. */
8062 {
8069 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8070 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8071 We don't want to pack more than two leafs to a non-IF AND/OR
8072 expression.
8073 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8074 equal to IF-CODE, then we don't want to add right-hand operand.
8075 If the inner right-hand side of left-hand operand has
8076 side-effects, or isn't simple, then we can't add to it,
8077 as otherwise we might destroy if-sequence. */
8080 /* Needed for sequence points to handle trappings, and
8081 side-effects. */
8083 {
8085 arg1);
8087 tem);
8088 }
8089 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8090 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8093 /* Needed for sequence points to handle trappings, and
8094 side-effects. */
8096 {
8101 }
8102 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8103 into (A OR B).
8104 For sequence point consistancy, we need to check for trapping,
8105 and side-effects. */
8109 }
8112 }
8114 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8115 by changing CODE to reduce the magnitude of constants involved in
8116 ARG0 of the comparison.
8117 Returns a canonicalized comparison tree if a simplification was
8118 possible, otherwise returns NULL_TREE.
8119 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8120 valid if signed overflow is undefined. */
8122 static tree
8126 {
8131 /* Match A +- CST code arg1. We can change this only if overflow
8132 is undefined. */
8135 /* In principle pointers also have undefined overflow behavior,
8136 but that causes problems elsewhere. */
8143 /* Identify the constant in arg0 and its sign. */
8147 /* Overflowed constants and zero will cause problems. */
8152 /* See if we can reduce the magnitude of the constant in
8153 arg0 by changing the comparison code. */
8154 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8158 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8162 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8166 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8170 else
8174 /* Now build the constant reduced in magnitude. But not if that
8175 would produce one outside of its types range. */
8191 }
8193 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8194 overflow further. Try to decrease the magnitude of constants involved
8195 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8196 and put sole constants at the second argument position.
8197 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8199 static tree
8202 {
8203 tree t;
8208 /* Try canonicalization by simplifying arg0. */
8213 {
8217 }
8219 /* Try canonicalization by simplifying arg1 using the swapped
8220 comparison. */
8228 }
8230 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8231 space. This is used to avoid issuing overflow warnings for
8232 expressions like &p->x which can not wrap. */
8234 static bool
8236 {
8243 wide_int wi_offset;
8249 else
8265 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8266 array. */
8268 {
8269 HOST_WIDE_INT base_size;
8274 }
8277 }
8279 /* Return a positive integer when the symbol DECL is known to have
8280 a nonzero address, zero when it's known not to (e.g., it's a weak
8281 symbol), and a negative integer when the symbol is not yet in the
8282 symbol table and so whether or not its address is zero is unknown.
8283 For function local objects always return positive integer. */
8284 static int
8286 {
8291 /* Function local objects are never NULL. */
8299 }
8301 /* Subroutine of fold_binary. This routine performs all of the
8302 transformations that are common to the equality/inequality
8303 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8304 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8305 fold_binary should call fold_binary. Fold a comparison with
8306 tree code CODE and type TYPE with operands OP0 and OP1. Return
8307 the folded comparison or NULL_TREE. */
8309 static tree
8312 {
8322 /* For comparisons of pointers we can decompose it to a compile time
8323 comparison of the base objects and the offsets into the object.
8324 This requires at least one operand being an ADDR_EXPR or a
8325 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8331 {
8334 machine_mode mode;
8338 /* Get base and offset for the access. Strip ADDR_EXPR for
8339 get_inner_reference, but put it back by stripping INDIRECT_REF
8340 off the base object if possible. indirect_baseN will be true
8341 if baseN is not an address but refers to the object itself. */
8344 {
8345 base0
8351 else
8353 }
8355 {
8359 {
8360 base0
8366 else
8368 }
8371 else
8375 {
8381 {
8384 }
8385 }
8386 }
8390 {
8391 base1
8397 else
8399 }
8401 {
8405 {
8406 base1
8412 else
8414 }
8417 else
8421 {
8427 {
8430 }
8431 }
8432 }
8434 /* If we have equivalent bases we might be able to simplify. */
8438 {
8439 /* We can fold this expression to a constant if the non-constant
8440 offset parts are equal. */
8444 && (equality_code
8445 || (indirect_base0
8449 {
8455 "occur when comparing P +- C1 with "
8457 WARN_STRICT_OVERFLOW_CONDITIONAL);
8460 {
8474 }
8475 }
8476 /* We can simplify the comparison to a comparison of the variable
8477 offset parts if the constant offset parts are equal.
8478 Be careful to use signed sizetype here because otherwise we
8479 mess with array offsets in the wrong way. This is possible
8480 because pointer arithmetic is restricted to retain within an
8481 object and overflow on pointer differences is undefined as of
8482 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8484 && (equality_code
8485 || (indirect_base0
8488 {
8489 /* By converting to signed sizetype we cover middle-end pointer
8490 arithmetic which operates on unsigned pointer types of size
8491 type size and ARRAY_REF offsets which are properly sign or
8492 zero extended from their type in case it is narrower than
8493 sizetype. */
8496 else
8500 else
8507 "occur when comparing P +- C1 with "
8509 WARN_STRICT_OVERFLOW_COMPARISON);
8512 }
8513 }
8514 /* For equal offsets we can simplify to a comparison of the
8515 base addresses. */
8517 && (indirect_base0
8519 && (indirect_base1
8524 {
8530 }
8531 /* Comparison between an ordinary (non-weak) symbol and a null
8532 pointer can be eliminated since such symbols must have a non
8533 null address. In C, relational expressions between pointers
8534 to objects and null pointers are undefined. The results
8535 below follow the C++ rules with the additional property that
8536 every object pointer compares greater than a null pointer.
8537 */
8540 /* Avoid folding references to struct members at offset 0 to
8541 prevent tests like '&ptr->firstmember == 0' from getting
8542 eliminated. When ptr is null, although the -> expression
8543 is strictly speaking invalid, GCC retains it as a matter
8544 of QoI. See PR c/44555. */
8547 && indirect_base0
8548 /* The caller guarantees that when one of the arguments is
8549 constant (i.e., null in this case) it is second. */
8551 {
8553 {
8564 }
8565 }
8566 }
8568 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8569 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8570 the resulting offset is smaller in absolute value than the
8571 original one and has the same sign. */
8580 {
8585 tree cst;
8587 "occur when combining constants around "
8590 /* Put the constant on the side where it doesn't overflow and is
8591 of lower absolute value and of same sign than before. */
8598 {
8601 variable1,
8605 }
8613 {
8619 variable2);
8620 }
8621 }
8627 /* If we are comparing an expression that just has comparisons
8628 of two integer values, arithmetic expressions of those comparisons,
8629 and constants, we can simplify it. There are only three cases
8630 to check: the two values can either be equal, the first can be
8631 greater, or the second can be greater. Fold the expression for
8632 those three values. Since each value must be 0 or 1, we have
8633 eight possibilities, each of which corresponds to the constant 0
8634 or 1 or one of the six possible comparisons.
8636 This handles common cases like (a > b) == 0 but also handles
8637 expressions like ((x > y) - (y > x)) > 0, which supposedly
8638 occur in macroized code. */
8641 {
8646 /* Don't handle degenerate cases here; they should already
8647 have been handled anyway. */
8656 {
8660 /* We can't just pass T to eval_subst in case cval1 or cval2
8661 was the same as ARG1. */
8663 tree high_result
8667 arg1);
8668 tree equal_result
8672 arg1);
8673 tree low_result
8677 arg1);
8679 /* All three of these results should be 0 or 1. Confirm they are.
8680 Then use those values to select the proper code to use. */
8685 {
8686 /* Make a 3-bit mask with the high-order bit being the
8687 value for `>', the next for '=', and the low for '<'. */
8691 {
8693 /* Always false. */
8714 /* Always true. */
8716 }
8719 {
8723 }
8725 }
8726 }
8727 }
8729 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8730 into a single range test. */
8737 {
8741 }
8744 }
8747 /* Subroutine of fold_binary. Optimize complex multiplications of the
8748 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8749 argument EXPR represents the expression "z" of type TYPE. */
8751 static tree
8753 {
8758 {
8761 }
8763 {
8766 }
8767 else
8768 {
8772 }
8781 }
8784 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8785 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8787 static bool
8789 {
8793 {
8796 }
8798 {
8804 else
8806 }
8807 else
8813 }
8815 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8816 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8817 NULL_TREE otherwise. */
8819 static tree
8821 {
8838 {
8842 }
8845 {
8851 }
8852 else
8854 }
8856 /* Try to fold a pointer difference of type TYPE two address expressions of
8857 array references AREF0 and AREF1 using location LOC. Return a
8858 simplified expression for the difference or NULL_TREE. */
8860 static tree
8863 {
8868 /* If the bases are array references as well, recurse. If the bases
8869 are pointer indirections compute the difference of the pointers.
8870 If the bases are equal, we are set. */
8873 && (base_offset
8877 && (base_offset
8883 {
8889 base_offset,
8892 }
8894 }
8896 /* If the real or vector real constant CST of type TYPE has an exact
8897 inverse, return it, else return NULL. */
8899 tree
8901 {
8902 REAL_VALUE_TYPE r;
8904 machine_mode mode;
8908 {
8924 {
8929 }
8935 }
8936 }
8938 /* Mask out the tz least significant bits of X of type TYPE where
8939 tz is the number of trailing zeroes in Y. */
8940 static wide_int
8942 {
8947 }
8949 /* Return true when T is an address and is known to be nonzero.
8950 For floating point we further ensure that T is not denormal.
8951 Similar logic is present in nonzero_address in rtlanal.h.
8953 If the return value is based on the assumption that signed overflow
8954 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8955 change *STRICT_OVERFLOW_P. */
8957 static bool
8959 {
8963 /* Doing something useful for floating point would need more work. */
8969 {
8972 strict_overflow_p);
8978 strict_overflow_p);
8986 }
8989 {
8992 strict_overflow_p);
9000 strict_overflow_p);
9015 strict_overflow_p);
9019 strict_overflow_p);
9022 {
9034 }
9038 }
9040 }
9042 /* Return true when T is an address and is known to be nonzero.
9043 Handle warnings about undefined signed overflow. */
9045 bool
9047 {
9054 "determining that expression is always "
9056 WARN_STRICT_OVERFLOW_MISC);
9058 }
9060 /* Return true if T is known not to be equal to an integer W. */
9062 bool
9064 {
9066 value_range_type rtype;
9068 {
9077 {
9082 }
9087 /* If T has some known zero bits and W has any of those bits set,
9088 then T is known not to be equal to W. */
9096 }
9097 }
9099 /* Fold a binary expression of code CODE and type TYPE with operands
9100 OP0 and OP1. LOC is the location of the resulting expression.
9101 Return the folded expression if folding is successful. Otherwise,
9102 return NULL_TREE. */
9104 tree
9107 {
9122 /* Strip any conversions that don't change the mode. This is
9123 safe for every expression, except for a comparison expression
9124 because its signedness is derived from its operands. So, in
9125 the latter case, only strip conversions that don't change the
9126 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9127 preserved.
9129 Note that this is done as an internal manipulation within the
9130 constant folder, in order to find the simplest representation
9131 of the arguments so that their form can be studied. In any
9132 cases, the appropriate type conversions should be put back in
9133 the tree that will get out of the constant folder. */
9136 {
9139 }
9140 else
9141 {
9144 }
9146 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9147 constant but we can't do arithmetic on them. */
9149 {
9152 {
9156 }
9157 }
9159 /* If this is a commutative operation, and ARG0 is a constant, move it
9160 to ARG1 to reduce the number of tests below. */
9165 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9166 to ARG1 to reduce the number of tests below. */
9175 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9177 First check for cases where an arithmetic operation is applied to a
9178 compound, conditional, or comparison operation. Push the arithmetic
9179 operation inside the compound or conditional to see if any folding
9180 can then be done. Convert comparison to conditional for this purpose.
9181 The also optimizes non-constant cases that used to be done in
9182 expand_expr.
9184 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9185 one of the operands is a comparison and the other is a comparison, a
9186 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9187 code below would make the expression more complex. Change it to a
9188 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9189 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9202 {
9206 boolean_type_node,
9214 }
9218 {
9220 {
9225 tem);
9226 }
9228 {
9233 tem);
9234 }
9239 {
9245 }
9250 {
9256 }
9257 }
9260 {
9262 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9265 {
9271 }
9273 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9276 {
9277 tree base;
9278 HOST_WIDE_INT coffset;
9287 }
9292 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9298 arg1),
9300 arg0)));
9306 {
9307 /* X + (X / CST) * -CST is X % CST. */
9312 {
9321 cst0));
9322 }
9323 }
9325 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9326 one. Make sure the type is not saturating and has the signedness of
9327 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9328 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9335 {
9339 }
9342 {
9343 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9344 (plus (plus (mult) (mult)) (foo)) so that we can
9345 take advantage of the factoring cases below. */
9354 {
9360 else
9373 parg0),
9375 marg)),
9379 return
9385 parg1)));
9386 }
9387 }
9388 else
9389 {
9390 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9391 to __complex__ ( x, y ). This is not the same for SNaNs or
9392 if signed zeros are involved. */
9396 {
9403 {
9407 {
9413 }
9415 {
9421 }
9422 }
9423 }
9431 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9432 We associate floats only if the user has specified
9433 -fassociative-math. */
9437 {
9442 {
9443 tree tree0;
9446 }
9447 }
9448 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9449 We associate floats only if the user has specified
9450 -fassociative-math. */
9454 {
9459 {
9460 tree tree0;
9463 }
9464 }
9465 }
9467 bit_rotate:
9468 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9469 is a rotate of A by C1 bits. */
9470 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9471 is a rotate of A by B bits. */
9472 {
9474 tree rtype;
9483 /* Only create rotates in complete modes. Other cases are not
9484 expanded properly. */
9487 {
9501 {
9505 code0 == LSHIFT_EXPR
9509 }
9511 {
9519 element_precision
9523 return
9526 ? LROTATE_EXPR
9531 }
9533 {
9541 element_precision
9545 return fold_convert_loc
9548 ? LROTATE_EXPR
9552 }
9553 }
9554 }
9556 associate:
9557 /* In most languages, can't associate operations on floats through
9558 parentheses. Rather than remember where the parentheses were, we
9559 don't associate floats at all, unless the user has specified
9560 -fassociative-math.
9561 And, we need to make sure type is not saturating. */
9565 {
9571 /* Split both trees into variables, constants, and literals. Then
9572 associate each group together, the constants with literals,
9573 then the result with variables. This increases the chances of
9574 literals being recombined later and of generating relocatable
9575 expressions for the sum of a constant and literal. */
9581 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9585 /* With undefined overflow prefer doing association in a type
9586 which wraps on overflow, if that is one of the operand types. */
9589 {
9597 }
9599 /* With undefined overflow we can only associate constants with one
9600 variable, and constants whose association doesn't overflow. */
9603 {
9605 {
9611 {
9614 }
9621 {
9624 }
9630 /* The only case we can still associate with two variables
9631 is if they cancel out. */
9635 }
9636 }
9638 /* Only do something if we found more than two objects. Otherwise,
9639 nothing has changed and we risk infinite recursion. */
9645 {
9657 /* Preserve the MINUS_EXPR if the negative part of the literal is
9658 greater than the positive part. Otherwise, the multiplicative
9659 folding code (i.e extract_muldiv) may be fooled in case
9660 unsigned constants are subtracted, like in the following
9661 example: ((X*2 + 4) - 8U)/2. */
9663 {
9667 {
9671 }
9672 else
9673 {
9677 }
9678 }
9680 /* Don't introduce overflows through reassociation. */
9687 {
9689 return
9693 else
9694 {
9697 return
9701 }
9702 }
9705 return
9708 }
9709 }
9714 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9722 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9723 __complex__ ( x, -y ). This is not the same for SNaNs or if
9724 signed zeros are involved. */
9728 {
9735 {
9739 {
9741 arg1r ? arg1r
9746 }
9748 {
9752 arg1i ? arg1i
9755 }
9756 }
9757 }
9759 /* A - B -> A + (-B) if B is easily negatable. */
9763 /* Avoid this transformation if B is a positive REAL_CST. */
9771 /* Fold &a[i] - &a[j] to i-j. */
9776 {
9782 }
9785 && flag_unsafe_math_optimizations
9791 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9792 one. Make sure the type is not saturating and has the signedness of
9793 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9794 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9801 {
9805 }
9811 {
9812 /* Transform x * -C into -x * C if x is easily negatable. */
9826 {
9829 "occur when simplifying "
9831 WARN_STRICT_OVERFLOW_MISC);
9833 }
9835 /* Optimize z * conj(z) for integer complex numbers. */
9842 }
9843 else
9844 {
9845 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9846 This is not the same for NaNs or if signed zeros are
9847 involved. */
9853 {
9856 return
9862 return
9867 }
9869 /* Optimize z * conj(z) for floating point complex numbers.
9870 Guarded by flag_unsafe_math_optimizations as non-finite
9871 imaginary components don't produce scalar results. */
9880 }
9884 /* Canonicalize (X & C1) | C2. */
9888 {
9893 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9901 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9903 {
9906 }
9908 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9909 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9910 mode which allows further optimizations. */
9915 {
9919 {
9922 }
9923 }
9926 {
9931 }
9932 }
9934 /* See if this can be simplified into a rotate first. If that
9935 is unsuccessful continue in the association code. */
9939 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9947 /* See if this can be simplified into a rotate first. If that
9948 is unsuccessful continue in the association code. */
9952 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9957 {
9958 tree tem2;
9965 }
9966 /* Fold ~X & 1 as (X & 1) == 0. */
9970 {
9971 tree tem2;
9978 }
9979 /* Fold !X & 1 as X == 0. */
9982 {
9986 }
9988 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
9989 multiple of 1 << CST. */
9991 {
9998 }
10000 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10001 bits from CST2. */
10005 {
10013 {
10014 /* Avoid the transform if arg1 is a mask of some
10015 mode which allows further optimizations. */
10022 }
10023 }
10025 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10026 ((A & N) + B) & M -> (A + B) & M
10027 Similarly if (N & M) == 0,
10028 ((A | N) + B) & M -> (A + B) & M
10029 and for - instead of + (or unary - instead of +)
10030 and/or ^ instead of |.
10031 If B is constant and (B & M) == 0, fold into A & M. */
10033 {
10042 {
10045 wide_int cst0;
10047 /* Now we know that arg0 is (C + D) or (C - D) or
10048 -C and arg1 (M) is == (1LL << cst) - 1.
10049 Store C into PMOP[0] and D into PMOP[1]. */
10053 {
10056 }
10063 {
10073 {
10076 }
10079 /* If C or D is of the form (A & N) where
10080 (N & M) == M, or of the form (A | N) or
10081 (A ^ N) where (N & M) == 0, replace it with A. */
10085 /* If C or D is a N where (N & M) == 0, it can be
10086 omitted (assumed 0). */
10094 }
10096 /* Only build anything new if we optimized one or both arguments
10097 above. */
10101 {
10104 {
10105 /* Perform the operations in a type that has defined
10106 overflow behavior. */
10112 }
10117 {
10125 else
10127 }
10130 else
10133 /* TEM is now the new binary +, - or unary - replacement. */
10137 }
10138 }
10139 }
10141 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10144 {
10149 return
10151 }
10156 /* Don't touch a floating-point divide by zero unless the mode
10157 of the constant can represent infinity. */
10163 /* (-A) / (-B) -> A / B */
10175 /* Fall through */
10178 /* Simplify A / (B << N) where A and B are positive and B is
10179 a power of 2, to A >> (N + log2(B)). */
10184 {
10187 {
10195 WARN_STRICT_OVERFLOW_MISC);
10201 }
10202 }
10204 /* Fall through */
10212 /* Convert -A / -B to A / B when the type is signed and overflow is
10213 undefined. */
10217 {
10220 "when distributing negation across "
10222 WARN_STRICT_OVERFLOW_MISC);
10227 }
10231 {
10234 "when distributing negation across "
10236 WARN_STRICT_OVERFLOW_MISC);
10241 }
10243 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10244 operation, EXACT_DIV_EXPR.
10246 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10247 At one time others generated faster code, it's not clear if they do
10248 after the last round to changes to the DIV code in expmed.c. */
10259 {
10263 WARN_STRICT_OVERFLOW_MISC);
10265 }
10277 {
10281 WARN_STRICT_OVERFLOW_MISC);
10283 }
10291 /* Since negative shift count is not well-defined,
10292 don't try to compute it in the compiler. */
10298 /* If we have a rotate of a bit operation with the rotate count and
10299 the second operand of the bit operation both constant,
10300 permute the two operations. */
10306 {
10314 }
10316 /* Two consecutive rotates adding up to the some integer
10317 multiple of the precision of the type can be ignored. */
10332 /* Note that the operands of this must be ints
10333 and their values must be 0 or 1.
10334 ("true" is a fixed value perhaps depending on the language.) */
10335 /* If first arg is constant zero, return it. */
10338 /* FALLTHRU */
10340 /* If either arg is constant true, drop it. */
10344 /* Preserve sequence points. */
10347 /* If second arg is constant zero, result is zero, but first arg
10348 must be evaluated. */
10351 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10352 case will be handled here. */
10356 /* !X && X is always false. */
10360 /* X && !X is always false. */
10365 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10366 means A >= Y && A != MAX, but in this case we know that
10367 A < X <= MAX. */
10371 {
10379 }
10388 /* Note that the operands of this must be ints
10389 and their values must be 0 or true.
10390 ("true" is a fixed value perhaps depending on the language.) */
10391 /* If first arg is constant true, return it. */
10394 /* FALLTHRU */
10396 /* If either arg is constant zero, drop it. */
10400 /* Preserve sequence points. */
10403 /* If second arg is constant true, result is true, but we must
10404 evaluate first arg. */
10407 /* Likewise for first arg, but note this only occurs here for
10408 TRUTH_OR_EXPR. */
10412 /* !X || X is always true. */
10416 /* X || !X is always true. */
10421 /* (X && !Y) || (!X && Y) is X ^ Y */
10424 {
10441 }
10450 /* If the second arg is constant zero, drop it. */
10453 /* If the second arg is constant true, this is a logical inversion. */
10455 {
10458 }
10459 /* Identical arguments cancel to zero. */
10463 /* !X ^ X is always true. */
10468 /* X ^ !X is always true. */
10484 /* bool_var != 1 becomes !bool_var. */
10491 /* bool_var == 0 becomes !bool_var. */
10498 /* !exp != 0 becomes !exp */
10503 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10512 {
10518 }
10520 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10529 {
10535 }
10537 /* If this is an EQ or NE comparison with zero and ARG0 is
10538 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10539 two operations, but the latter can be done in one less insn
10540 on machines that have only two-operand insns or on which a
10541 constant cannot be the first operand. */
10544 {
10549 {
10556 arg1);
10557 }
10560 {
10567 arg1);
10568 }
10569 }
10571 /* If this is an NE or EQ comparison of zero against the result of a
10572 signed MOD operation whose second operand is a power of 2, make
10573 the MOD operation unsigned since it is simpler and equivalent. */
10581 {
10591 }
10593 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10594 C1 is a valid shift constant, and C2 is a power of two, i.e.
10595 a single bit. */
10599 == INTEGER_CST
10602 {
10607 /* Check for a valid shift count. */
10609 {
10613 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10614 can be rewritten as (X & (C2 << C1)) != 0. */
10616 {
10621 }
10622 /* Otherwise, for signed (arithmetic) shifts,
10623 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10624 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10628 /* Otherwise, of unsigned (logical) shifts,
10629 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10630 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10631 else
10635 arg000);
10636 }
10637 }
10639 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
10640 Similarly for NE_EXPR. */
10644 {
10648 tree dandnotc
10651 notc);
10655 }
10657 /* If this is a comparison of a field, we may be able to simplify it. */
10660 /* Handle the constant case even without -O
10661 to make sure the warnings are given. */
10663 {
10667 }
10669 /* Optimize comparisons of strlen vs zero to a compare of the
10670 first character of the string vs zero. To wit,
10671 strlen(ptr) == 0 => *ptr == 0
10672 strlen(ptr) != 0 => *ptr != 0
10673 Other cases should reduce to one of these two (or a constant)
10674 due to the return value of strlen being unsigned. */
10677 {
10685 {
10690 }
10691 }
10693 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10694 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10698 {
10703 {
10705 {
10708 }
10711 }
10712 }
10714 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10715 (X & C) == 0 when C is a single bit. */
10720 {
10727 arg1));
10728 }
10730 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10731 constant C is a power of two, i.e. a single bit. */
10738 {
10742 }
10744 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10745 when is C is a power of two, i.e. a single bit. */
10752 {
10758 }
10762 {
10765 }
10767 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10770 {
10778 {
10784 }
10786 {
10792 }
10794 {
10800 }
10802 {
10808 }
10809 }
10813 {
10820 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10821 operand_equal_p guarantees no side-effects so we don't need
10822 to use omit_one_operand on Z. */
10826 arg10));
10830 arg11));
10834 arg10));
10838 arg11));
10840 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10843 {
10849 }
10850 }
10852 /* Attempt to simplify equality/inequality comparisons of complex
10853 values. Only lower the comparison if the result is known or
10854 can be simplified to a single scalar comparison. */
10859 {
10864 {
10867 }
10868 else
10869 {
10872 }
10875 {
10878 }
10879 else
10880 {
10883 }
10887 {
10889 {
10894 }
10895 else
10896 {
10901 }
10902 }
10906 {
10908 {
10913 }
10914 else
10915 {
10920 }
10921 }
10922 }
10934 /* Transform comparisons of the form X +- C CMP X. */
10941 {
10948 else
10951 /* (X - c) > X becomes false. */
10955 {
10959 "occur when assuming that (X - c) > X "
10961 WARN_STRICT_OVERFLOW_ALL);
10963 }
10965 /* Likewise (X + c) < X becomes false. */
10969 {
10973 "occur when assuming that "
10975 WARN_STRICT_OVERFLOW_ALL);
10977 }
10979 /* Convert (X - c) <= X to true. */
10984 {
10988 "occur when assuming that "
10990 WARN_STRICT_OVERFLOW_ALL);
10992 }
10994 /* Convert (X + c) >= X to true. */
10999 {
11003 "occur when assuming that "
11005 WARN_STRICT_OVERFLOW_ALL);
11007 }
11010 {
11011 /* Convert X + c > X and X - c < X to true for integers. */
11015 {
11018 "not occur when assuming that "
11020 WARN_STRICT_OVERFLOW_ALL);
11022 }
11027 {
11030 "not occur when assuming that "
11032 WARN_STRICT_OVERFLOW_ALL);
11034 }
11036 /* Convert X + c <= X and X - c >= X to false for integers. */
11040 {
11043 "not occur when assuming that "
11045 WARN_STRICT_OVERFLOW_ALL);
11047 }
11052 {
11055 "not occur when assuming that "
11057 WARN_STRICT_OVERFLOW_ALL);
11059 }
11060 }
11061 }
11063 /* If we are comparing an ABS_EXPR with a constant, we can
11064 convert all the cases into explicit comparisons, but they may
11065 well not be faster than doing the ABS and one comparison.
11066 But ABS (X) <= C is a range comparison, which becomes a subtraction
11067 and a comparison, and is probably faster. */
11081 /* Convert ABS_EXPR<x> >= 0 to true. */
11088 {
11091 "when simplifying comparison of "
11093 WARN_STRICT_OVERFLOW_CONDITIONAL);
11096 arg0);
11097 }
11099 /* Convert ABS_EXPR<x> < 0 to false. */
11104 {
11107 "when simplifying comparison of "
11109 WARN_STRICT_OVERFLOW_CONDITIONAL);
11112 arg0);
11113 }
11115 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11116 and similarly for >= into !=. */
11126 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11127 otherwise Y might be >= # of bits in X's type and thus e.g.
11128 (unsigned char) (1 << Y) for Y 15 might be 0.
11129 If the cast is widening, then 1 << Y should have unsigned type,
11130 otherwise if Y is number of bits in the signed shift type minus 1,
11131 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11132 31 might be 0xffffffff80000000. */
11143 {
11149 }
11161 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11162 {
11174 }
11179 /* When pedantic, a compound expression can be neither an lvalue
11180 nor an integer constant expression. */
11183 /* Don't let (0, 0) be null pointer constant. */
11189 /* An ASSERT_EXPR should never be passed to fold_binary. */
11195 }
11197 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11198 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11199 of GOTO_EXPR. */
11201 static tree
11203 {
11205 {
11212 /* fall through */
11216 }
11217 }
11219 /* Return whether the sub-tree ST contains a label which is accessible from
11220 outside the sub-tree. */
11222 static bool
11224 {
11225 return
11227 }
11229 /* Fold a ternary expression of code CODE and type TYPE with operands
11230 OP0, OP1, and OP2. Return the folded expression if folding is
11231 successful. Otherwise, return NULL_TREE. */
11233 tree
11236 {
11237 tree tem;
11244 /* If this is a commutative operation, and OP0 is a constant, move it
11245 to OP1 to reduce the number of tests below. */
11254 /* Strip any conversions that don't change the mode. This is safe
11255 for every expression, except for a comparison expression because
11256 its signedness is derived from its operands. So, in the latter
11257 case, only strip conversions that don't change the signedness.
11259 Note that this is done as an internal manipulation within the
11260 constant folder, in order to find the simplest representation of
11261 the arguments so that their form can be studied. In any cases,
11262 the appropriate type conversions should be put back in the tree
11263 that will get out of the constant folder. */
11265 {
11268 }
11271 {
11274 }
11277 {
11280 }
11283 {
11287 {
11293 }
11298 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11299 so all simple results must be passed through pedantic_non_lvalue. */
11301 {
11304 /* Only optimize constant conditions when the selected branch
11305 has the same type as the COND_EXPR. This avoids optimizing
11306 away "c ? x : throw", where the throw has a void type.
11307 Avoid throwing away that operand which contains label. */
11314 }
11316 {
11321 {
11326 {
11334 }
11338 }
11339 }
11341 /* If we have A op B ? A : C, we may be able to convert this to a
11342 simpler expression, depending on the operation and the values
11343 of B and C. Signed zeros prevent all of these transformations,
11344 for reasons given above each one.
11346 Also try swapping the arguments and inverting the conditional. */
11351 {
11355 }
11359 op2,
11362 {
11366 {
11370 }
11371 }
11373 /* If the second operand is simpler than the third, swap them
11374 since that produces better jump optimization results. */
11377 {
11379 /* See if this can be inverted. If it can't, possibly because
11380 it was a floating-point inequality comparison, don't do
11381 anything. */
11385 }
11387 /* Convert A ? 1 : 0 to simply A. */
11392 /* If we try to convert OP0 to our type, the
11393 call to fold will try to move the conversion inside
11394 a COND, which will recurse. In that case, the COND_EXPR
11395 is probably the best choice, so leave it alone. */
11399 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11400 over COND_EXPR in cases such as floating point comparisons. */
11409 arg0)));
11411 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11416 {
11417 /* sign_bit_p looks through both zero and sign extensions,
11418 but for this optimization only sign extensions are
11419 usable. */
11422 {
11425 {
11428 }
11430 }
11431 /* sign_bit_p only checks ARG1 bits within A's precision.
11432 If <sign bit of A> has wider type than A, bits outside
11433 of A's precision in <sign bit of A> need to be checked.
11434 If they are all 0, this optimization needs to be done
11435 in unsigned A's type, if they are all 1 in signed A's type,
11436 otherwise this can't be done. */
11442 {
11444 tree tem_type;
11457 {
11460 }
11462 {
11465 }
11466 else
11468 }
11471 return
11477 arg1)));
11478 }
11480 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11481 already handled above. */
11486 {
11496 op1);
11497 }
11499 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11500 is probably obsolete because the first operand should be a
11501 truth value (that's why we have the two cases above), but let's
11502 leave it in until we can confirm this for all front-ends. */
11514 /* Disable the transformations below for vectors, since
11515 fold_binary_op_with_conditional_arg may undo them immediately,
11516 yielding an infinite loop. */
11520 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11529 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11534 {
11536 /* Only perform transformation if ARG0 is easily inverted. */
11540 ? BIT_IOR_EXPR
11543 op1);
11544 }
11546 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11551 {
11553 /* Only perform transformation if ARG0 is easily inverted. */
11559 op2);
11560 }
11562 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11574 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11575 of fold_ternary on them. */
11583 {
11593 {
11598 {
11606 }
11607 }
11608 }
11610 /* On constants we can use native encode/interpret to constant
11611 fold (nearly) all BIT_FIELD_REFs. */
11615 {
11618 /* Limit us to a reasonable amount of work. To relax the
11619 other limitations we need bit-shifting of the buffer
11620 and rounding up the size. */
11624 {
11626 unsigned HOST_WIDE_INT len
11631 {
11636 }
11637 }
11638 }
11643 /* For integers we can decompose the FMA if possible. */
11655 {
11671 {
11676 /* Make sure that the perm value is in an acceptable
11677 range. */
11686 else
11691 }
11694 {
11699 }
11704 {
11709 }
11715 {
11719 }
11724 /* Some targets are deficient and fail to expand a single
11725 argument permutation while still allowing an equivalent
11726 2-argument version. */
11730 {
11733 }
11736 {
11743 }
11747 }
11751 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11754 {
11760 wide_int tem2
11764 }
11769 {
11771 unsigned HOST_WIDE_INT elsize
11774 {
11778 else
11779 {
11785 }
11786 }
11787 }
11793 }
11795 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11796 of an array (or vector). */
11798 tree
11800 {
11805 {
11808 {
11809 /* Static constructors for variably sized objects makes no sense. */
11813 }
11814 }
11825 offset_int max_index;
11830 {
11831 /* Array constructor might explicitly set index, or specify a range,
11832 or leave index NULL meaning that it is next index after previous
11833 one. */
11835 {
11838 else
11839 {
11843 }
11844 }
11845 else
11846 {
11852 }
11854 /* Do we have match? */
11858 }
11860 }
11862 /* Perform constant folding and related simplification of EXPR.
11863 The related simplifications include x*1 => x, x*0 => 0, etc.,
11864 and application of the associative law.
11865 NOP_EXPR conversions may be removed freely (as long as we
11866 are careful not to change the type of the overall expression).
11867 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11868 but we can constant-fold them if they have constant operands. */
11870 #ifdef ENABLE_FOLD_CHECKING
11871 # define fold(x) fold_1 (x)
11873 static
11874 #endif
11875 tree
11877 {
11881 tree tem;
11884 /* Return right away if a constant. */
11888 /* CALL_EXPR-like objects with variable numbers of operands are
11889 treated specially. */
11891 {
11893 {
11896 }
11898 }
11901 {
11906 {
11924 }
11925 }
11928 {
11930 {
11937 {
11942 }
11945 }
11947 /* Return a VECTOR_CST if possible. */
11949 {
11955 tree val;
11961 }
11969 }
11971 #ifdef ENABLE_FOLD_CHECKING
11972 #undef fold
11979 /* When --enable-checking=fold, compute a digest of expr before
11980 and after actual fold call to see if fold did not accidentally
11981 change original expr. */
11983 tree
11985 {
11986 tree ret;
12006 }
12008 void
12010 {
12021 }
12023 static void
12025 {
12027 }
12029 static void
12032 {
12038 recursive_label:
12048 {
12049 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12054 }
12062 {
12063 /* Allow these fields to be modified. */
12064 tree tmp;
12073 {
12076 }
12077 }
12088 {
12091 {
12106 }
12110 {
12123 }
12140 {
12146 }
12149 {
12151 {
12154 }
12156 }
12167 {
12170 }
12180 }
12181 }
12183 /* Helper function for outputting the checksum of a tree T. When
12184 debugging with gdb, you can "define mynext" to be "next" followed
12185 by "call debug_fold_checksum (op0)", then just trace down till the
12186 outputs differ. */
12188 DEBUG_FUNCTION void
12190 {
12205 }
12207 #endif
12209 /* Fold a unary tree expression with code CODE of type TYPE with an
12210 operand OP0. LOC is the location of the resulting expression.
12211 Return a folded expression if successful. Otherwise, return a tree
12212 expression with code CODE of type TYPE with an operand OP0. */
12214 tree
12217 {
12218 tree tem;
12219 #ifdef ENABLE_FOLD_CHECKING
12228 #endif
12234 #ifdef ENABLE_FOLD_CHECKING
12241 #endif
12243 }
12245 /* Fold a binary tree expression with code CODE of type TYPE with
12246 operands OP0 and OP1. LOC is the location of the resulting
12247 expression. Return a folded expression if successful. Otherwise,
12248 return a tree expression with code CODE of type TYPE with operands
12249 OP0 and OP1. */
12251 tree
12254 MEM_STAT_DECL)
12255 {
12256 tree tem;
12257 #ifdef ENABLE_FOLD_CHECKING
12274 #endif
12280 #ifdef ENABLE_FOLD_CHECKING
12295 #endif
12297 }
12299 /* Fold a ternary tree expression with code CODE of type TYPE with
12300 operands OP0, OP1, and OP2. Return a folded expression if
12301 successful. Otherwise, return a tree expression with code CODE of
12302 type TYPE with operands OP0, OP1, and OP2. */
12304 tree
12307 {
12308 tree tem;
12309 #ifdef ENABLE_FOLD_CHECKING
12333 #endif
12340 #ifdef ENABLE_FOLD_CHECKING
12363 #endif
12365 }
12367 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12368 arguments in ARGARRAY, and a null static chain.
12369 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12370 of type TYPE from the given operands as constructed by build_call_array. */
12372 tree
12375 {
12376 tree tem;
12377 #ifdef ENABLE_FOLD_CHECKING
12396 #endif
12402 #ifdef ENABLE_FOLD_CHECKING
12418 #endif
12420 }
12422 /* Perform constant folding and related simplification of initializer
12423 expression EXPR. These behave identically to "fold_buildN" but ignore
12424 potential run-time traps and exceptions that fold must preserve. */
12426 #define START_FOLD_INIT \
12427 int saved_signaling_nans = flag_signaling_nans;\
12428 int saved_trapping_math = flag_trapping_math;\
12429 int saved_rounding_math = flag_rounding_math;\
12430 int saved_trapv = flag_trapv;\
12431 int saved_folding_initializer = folding_initializer;\
12432 flag_signaling_nans = 0;\
12433 flag_trapping_math = 0;\
12434 flag_rounding_math = 0;\
12435 flag_trapv = 0;\
12436 folding_initializer = 1;
12438 #define END_FOLD_INIT \
12439 flag_signaling_nans = saved_signaling_nans;\
12440 flag_trapping_math = saved_trapping_math;\
12441 flag_rounding_math = saved_rounding_math;\
12442 flag_trapv = saved_trapv;\
12443 folding_initializer = saved_folding_initializer;
12445 tree
12448 {
12449 tree result;
12450 START_FOLD_INIT;
12454 END_FOLD_INIT;
12456 }
12458 tree
12461 {
12462 tree result;
12463 START_FOLD_INIT;
12467 END_FOLD_INIT;
12469 }
12471 tree
12474 {
12475 tree result;
12476 START_FOLD_INIT;
12480 END_FOLD_INIT;
12482 }
12484 #undef START_FOLD_INIT
12485 #undef END_FOLD_INIT
12487 /* Determine if first argument is a multiple of second argument. Return 0 if
12488 it is not, or we cannot easily determined it to be.
12490 An example of the sort of thing we care about (at this point; this routine
12491 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12492 fold cases do now) is discovering that
12494 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12496 is a multiple of
12498 SAVE_EXPR (J * 8)
12500 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12502 This code also handles discovering that
12504 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12506 is a multiple of 8 so we don't have to worry about dealing with a
12507 possible remainder.
12509 Note that we *look* inside a SAVE_EXPR only to determine how it was
12510 calculated; it is not safe for fold to do much of anything else with the
12511 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12512 at run time. For example, the latter example above *cannot* be implemented
12513 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12514 evaluation time of the original SAVE_EXPR is not necessarily the same at
12515 the time the new expression is evaluated. The only optimization of this
12516 sort that would be valid is changing
12518 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12520 divided by 8 to
12522 SAVE_EXPR (I) * SAVE_EXPR (J)
12524 (where the same SAVE_EXPR (J) is used in the original and the
12525 transformed version). */
12527 int
12529 {
12540 {
12542 /* Bitwise and provides a power of two multiple. If the mask is
12543 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12546 /* FALLTHRU */
12553 /* It is impossible to prove if op0 - op1 is multiple of bottom
12554 precisely, so be conservative here checking if both op0 and op1
12555 are multiple of bottom. Note we check the second operand first
12556 since it's usually simpler. */
12561 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12562 as op0 - 3 if the expression has unsigned type. For example,
12563 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12573 {
12575 /* const_binop may not detect overflow correctly,
12576 so check for it explicitly here. */
12580 size_one_node,
12581 op1)))
12584 }
12588 /* Can't handle conversions from non-integral or wider integral type. */
12594 /* fall through */
12611 SIGNED);
12617 {
12620 /* Check for special cases to see if top is defined as multiple
12621 of bottom:
12623 top = (X & ~(bottom - 1) ; bottom is power of 2
12625 or
12627 Y = X % bottom
12628 top = X - Y. */
12647 }
12649 /* fall through */
12653 }
12654 }
12656 #define tree_expr_nonnegative_warnv_p(X, Y) \
12659 #define RECURSE(X) \
12660 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12662 /* Return true if CODE or TYPE is known to be non-negative. */
12664 static bool
12666 {
12669 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12670 have a signed:1 type (where the value is -1 and 0). */
12673 }
12675 /* Return true if (CODE OP0) is known to be non-negative. If the return
12676 value is based on the assumption that signed overflow is undefined,
12677 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12678 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12680 bool
12683 {
12688 {
12690 /* We can't return 1 if flag_wrapv is set because
12691 ABS_EXPR<INT_MIN> = INT_MIN. */
12695 {
12698 }
12706 CASE_CONVERT:
12707 {
12712 {
12716 {
12720 }
12721 }
12723 {
12729 }
12730 }
12735 }
12737 /* We don't know sign of `t', so be conservative and return false. */
12739 }
12741 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12742 value is based on the assumption that signed overflow is undefined,
12743 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12744 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12746 bool
12750 {
12755 {
12761 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12762 both unsigned and at least 2 bits shorter than the result. */
12766 {
12771 {
12775 }
12776 }
12781 {
12782 /* x * x is always non-negative for floating point x
12783 or without overflow. */
12786 {
12791 }
12792 }
12794 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12795 both unsigned and their total bits is shorter than the result. */
12799 {
12818 {
12828 }
12829 }
12856 }
12858 /* We don't know sign of `t', so be conservative and return false. */
12860 }
12862 /* Return true if T is known to be non-negative. If the return
12863 value is based on the assumption that signed overflow is undefined,
12864 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12865 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12867 bool
12869 {
12874 {
12888 /* Limit the depth of recursion to avoid quadratic behavior.
12889 This is expected to catch almost all occurrences in practice.
12890 If this code misses important cases that unbounded recursion
12891 would not, passes that need this information could be revised
12892 to provide it through dataflow propagation. */
12900 }
12901 }
12903 /* Return true if T is known to be non-negative. If the return
12904 value is based on the assumption that signed overflow is undefined,
12905 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12906 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12908 bool
12911 {
12913 {
12914 CASE_CFN_ACOS:
12915 CASE_CFN_ACOSH:
12916 CASE_CFN_CABS:
12917 CASE_CFN_COSH:
12918 CASE_CFN_ERFC:
12919 CASE_CFN_EXP:
12920 CASE_CFN_EXP10:
12921 CASE_CFN_EXP2:
12922 CASE_CFN_FABS:
12923 CASE_CFN_FDIM:
12924 CASE_CFN_HYPOT:
12925 CASE_CFN_POW10:
12926 CASE_CFN_FFS:
12927 CASE_CFN_PARITY:
12928 CASE_CFN_POPCOUNT:
12929 CASE_CFN_CLZ:
12930 CASE_CFN_CLRSB:
12933 /* Always true. */
12936 CASE_CFN_SQRT:
12937 /* sqrt(-0.0) is -0.0. */
12942 CASE_CFN_ASINH:
12943 CASE_CFN_ATAN:
12944 CASE_CFN_ATANH:
12945 CASE_CFN_CBRT:
12946 CASE_CFN_CEIL:
12947 CASE_CFN_ERF:
12948 CASE_CFN_EXPM1:
12949 CASE_CFN_FLOOR:
12950 CASE_CFN_FMOD:
12951 CASE_CFN_FREXP:
12952 CASE_CFN_ICEIL:
12953 CASE_CFN_IFLOOR:
12954 CASE_CFN_IRINT:
12955 CASE_CFN_IROUND:
12956 CASE_CFN_LCEIL:
12957 CASE_CFN_LDEXP:
12958 CASE_CFN_LFLOOR:
12959 CASE_CFN_LLCEIL:
12960 CASE_CFN_LLFLOOR:
12961 CASE_CFN_LLRINT:
12962 CASE_CFN_LLROUND:
12963 CASE_CFN_LRINT:
12964 CASE_CFN_LROUND:
12965 CASE_CFN_MODF:
12966 CASE_CFN_NEARBYINT:
12967 CASE_CFN_RINT:
12968 CASE_CFN_ROUND:
12969 CASE_CFN_SCALB:
12970 CASE_CFN_SCALBLN:
12971 CASE_CFN_SCALBN:
12972 CASE_CFN_SIGNBIT:
12973 CASE_CFN_SIGNIFICAND:
12974 CASE_CFN_SINH:
12975 CASE_CFN_TANH:
12976 CASE_CFN_TRUNC:
12977 /* True if the 1st argument is nonnegative. */
12980 CASE_CFN_FMAX:
12981 /* True if the 1st OR 2nd arguments are nonnegative. */
12984 CASE_CFN_FMIN:
12985 /* True if the 1st AND 2nd arguments are nonnegative. */
12988 CASE_CFN_COPYSIGN:
12989 /* True if the 2nd argument is nonnegative. */
12992 CASE_CFN_POWI:
12993 /* True if the 1st argument is nonnegative or the second
12994 argument is an even integer. */
13000 CASE_CFN_POW:
13001 /* True if the 1st argument is nonnegative or the second
13002 argument is an even integer valued real. */
13004 {
13005 REAL_VALUE_TYPE c;
13006 HOST_WIDE_INT n;
13011 {
13012 REAL_VALUE_TYPE cint;
13016 }
13017 }
13022 }
13024 }
13026 /* Return true if T is known to be non-negative. If the return
13027 value is based on the assumption that signed overflow is undefined,
13028 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13029 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13031 static bool
13033 {
13039 {
13041 {
13045 /* If the initializer is non-void, then it's a normal expression
13046 that will be assigned to the slot. */
13050 /* Otherwise, the initializer sets the slot in some way. One common
13051 way is an assignment statement at the end of the initializer. */
13053 {
13061 else
13063 }
13069 }
13072 {
13078 arg0,
13079 arg1,
13081 }
13094 }
13095 }
13097 #undef RECURSE
13098 #undef tree_expr_nonnegative_warnv_p
13100 /* Return true if T is known to be non-negative. If the return
13101 value is based on the assumption that signed overflow is undefined,
13102 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13103 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13105 bool
13107 {
13114 {
13136 }
13139 {
13165 }
13166 }
13168 /* Return true if `t' is known to be non-negative. Handle warnings
13169 about undefined signed overflow. */
13171 bool
13173 {
13180 "determining that expression is always "
13182 WARN_STRICT_OVERFLOW_MISC);
13184 }
13187 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13188 For floating point we further ensure that T is not denormal.
13189 Similar logic is present in nonzero_address in rtlanal.h.
13191 If the return value is based on the assumption that signed overflow
13192 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13193 change *STRICT_OVERFLOW_P. */
13195 bool
13198 {
13200 {
13203 strict_overflow_p);
13206 {
13212 strict_overflow_p));
13213 }
13218 strict_overflow_p);
13222 }
13225 }
13227 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13228 For floating point we further ensure that T is not denormal.
13229 Similar logic is present in nonzero_address in rtlanal.h.
13231 If the return value is based on the assumption that signed overflow
13232 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13233 change *STRICT_OVERFLOW_P. */
13235 bool
13237 tree type,
13238 tree op0,
13240 {
13243 {
13247 {
13248 /* With the presence of negative values it is hard
13249 to say something. */
13256 /* One of operands must be positive and the other non-negative. */
13257 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13258 overflows, on a twos-complement machine the sum of two
13259 nonnegative numbers can never be zero. */
13261 strict_overflow_p)
13263 strict_overflow_p));
13264 }
13269 {
13271 strict_overflow_p)
13273 strict_overflow_p))
13274 {
13277 }
13278 }
13287 {
13290 }
13297 {
13301 /* When both operands are nonzero, then MAX must be too. */
13303 strict_overflow_p))
13306 /* MAX where operand 0 is positive is positive. */
13308 strict_overflow_p);
13309 }
13310 /* MAX where operand 1 is positive is positive. */
13315 {
13319 }
13324 strict_overflow_p)
13326 strict_overflow_p));
13330 }
13333 }
13335 /* Return true when T is an address and is known to be nonzero.
13336 For floating point we further ensure that T is not denormal.
13337 Similar logic is present in nonzero_address in rtlanal.h.
13339 If the return value is based on the assumption that signed overflow
13340 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13341 change *STRICT_OVERFLOW_P. */
13343 bool
13345 {
13348 {
13353 {
13365 /* For objects in symbol table check if we know they are non-zero.
13366 Don't do anything for variables and functions before symtab is built;
13367 it is quite possible that they will be declared weak later. */
13372 /* Constants are never weak. */
13377 }
13385 {
13389 }
13399 }
13401 }
13403 #define integer_valued_real_p(X) \
13406 #define RECURSE(X) \
13407 ((integer_valued_real_p) (X, depth + 1))
13409 /* Return true if the floating point result of (CODE OP0) has an
13410 integer value. We also allow +Inf, -Inf and NaN to be considered
13411 integer values. Return false for signaling NaN.
13413 DEPTH is the current nesting depth of the query. */
13415 bool
13417 {
13419 {
13426 CASE_CONVERT:
13427 {
13434 }
13438 }
13440 }
13442 /* Return true if the floating point result of (CODE OP0 OP1) has an
13443 integer value. We also allow +Inf, -Inf and NaN to be considered
13444 integer values. Return false for signaling NaN.
13446 DEPTH is the current nesting depth of the query. */
13448 bool
13450 {
13452 {
13462 }
13464 }
13466 /* Return true if the floating point result of calling FNDECL with arguments
13467 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13468 considered integer values. Return false for signaling NaN. If FNDECL
13469 takes fewer than 2 arguments, the remaining ARGn are null.
13471 DEPTH is the current nesting depth of the query. */
13473 bool
13475 {
13477 {
13478 CASE_CFN_CEIL:
13479 CASE_CFN_FLOOR:
13480 CASE_CFN_NEARBYINT:
13481 CASE_CFN_RINT:
13482 CASE_CFN_ROUND:
13483 CASE_CFN_TRUNC:
13486 CASE_CFN_FMIN:
13487 CASE_CFN_FMAX:
13492 }
13494 }
13496 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13497 has an integer value. We also allow +Inf, -Inf and NaN to be
13498 considered integer values. Return false for signaling NaN.
13500 DEPTH is the current nesting depth of the query. */
13502 bool
13504 {
13506 {
13514 /* Limit the depth of recursion to avoid quadratic behavior.
13515 This is expected to catch almost all occurrences in practice.
13516 If this code misses important cases that unbounded recursion
13517 would not, passes that need this information could be revised
13518 to provide it through dataflow propagation. */
13522 depth));
13526 }
13528 }
13530 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13531 has an integer value. We also allow +Inf, -Inf and NaN to be
13532 considered integer values. Return false for signaling NaN.
13534 DEPTH is the current nesting depth of the query. */
13536 static bool
13538 {
13540 {
13551 }
13553 }
13555 #undef RECURSE
13556 #undef integer_valued_real_p
13558 /* Return true if the floating point expression T has an integer value.
13559 We also allow +Inf, -Inf and NaN to be considered integer values.
13560 Return false for signaling NaN.
13562 DEPTH is the current nesting depth of the query. */
13564 bool
13566 {
13572 {
13588 }
13591 {
13597 {
13606 }
13610 }
13611 }
13613 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13614 attempt to fold the expression to a constant without modifying TYPE,
13615 OP0 or OP1.
13617 If the expression could be simplified to a constant, then return
13618 the constant. If the expression would not be simplified to a
13619 constant, then return NULL_TREE. */
13621 tree
13623 {
13626 }
13628 /* Given the components of a unary expression CODE, TYPE and OP0,
13629 attempt to fold the expression to a constant without modifying
13630 TYPE or OP0.
13632 If the expression could be simplified to a constant, then return
13633 the constant. If the expression would not be simplified to a
13634 constant, then return NULL_TREE. */
13636 tree
13638 {
13641 }
13643 /* If EXP represents referencing an element in a constant string
13644 (either via pointer arithmetic or array indexing), return the
13645 tree representing the value accessed, otherwise return NULL. */
13647 tree
13649 {
13653 {
13655 tree index;
13656 tree string;
13661 else
13662 {
13666 /* Optimize the special-case of a zero lower bound.
13668 We convert the low_bound to sizetype to avoid some problems
13669 with constant folding. (E.g. suppose the lower bound is 1,
13670 and its mode is QI. Without the conversion,l (ARRAY
13671 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13672 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13678 }
13691 }
13693 }
13695 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13696 an integer constant, real, or fixed-point constant.
13698 TYPE is the type of the result. */
13700 static tree
13702 {
13706 {
13708 {
13715 }
13722 {
13723 FIXED_VALUE_TYPE f;
13728 /* Propagate overflow flags. */
13732 }
13736 }
13739 }
13741 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13742 an integer constant or real constant.
13744 TYPE is the type of the result. */
13746 tree
13748 {
13752 {
13754 {
13755 /* If the value is unsigned or non-negative, then the absolute value
13756 is the same as the ordinary value. */
13760 /* If the value is negative, then the absolute value is
13761 its negation. */
13762 else
13763 {
13768 }
13769 }
13775 else
13781 }
13784 }
13786 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13787 constant. TYPE is the type of the result. */
13789 static tree
13791 {
13795 }
13797 /* Given CODE, a relational operator, the target type, TYPE and two
13798 constant operands OP0 and OP1, return the result of the
13799 relational operation. If the result is not a compile time
13800 constant, then return NULL_TREE. */
13802 static tree
13804 {
13807 /* From here on, the only cases we handle are when the result is
13808 known to be a constant. */
13811 {
13815 /* Handle the cases where either operand is a NaN. */
13817 {
13819 {
13847 }
13850 }
13853 }
13856 {
13860 }
13862 /* Handle equality/inequality of complex constants. */
13864 {
13875 else
13877 }
13880 {
13882 {
13883 /* Have vector comparison with scalar boolean result. */
13887 {
13895 }
13897 }
13904 {
13916 }
13919 }
13921 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13923 To compute GT, swap the arguments and do LT.
13924 To compute GE, do LT and invert the result.
13925 To compute LE, swap the arguments, do LT and invert the result.
13926 To compute NE, do EQ and invert the result.
13928 Therefore, the code below must handle only EQ and LT. */
13931 {
13934 }
13936 /* Note that it is safe to invert for real values here because we
13937 have already handled the one case that it matters. */
13941 {
13944 }
13946 /* Compute a result for LT or EQ if args permit;
13947 Otherwise return T. */
13949 {
13952 else
13954 }
13955 else
13961 }
13963 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13964 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13965 itself. */
13967 tree
13969 {
13970 /* If the expression does not have side effects then we don't have to wrap
13971 it with a cleanup point expression. */
13975 /* If the expression is a return, check to see if the expression inside the
13976 return has no side effects or the right hand side of the modify expression
13977 inside the return. If either don't have side effects set we don't need to
13978 wrap the expression in a cleanup point expression. Note we don't check the
13979 left hand side of the modify because it should always be a return decl. */
13981 {
13988 }
13991 }
13993 /* Given a pointer value OP0 and a type TYPE, return a simplified version
13994 of an indirection through OP0, or NULL_TREE if no simplification is
13995 possible. */
13997 tree
13999 {
14001 tree subtype;
14010 {
14013 /* *&CONST_DECL -> to the value of the const decl. */
14016 /* *&p => p; make sure to handle *&"str"[cst] here. */
14018 {
14022 else
14024 }
14025 /* *(foo *)&fooarray => fooarray[0] */
14028 && (!in_gimple_form
14030 {
14040 }
14041 /* *(foo *)&complexfoo => __real__ complexfoo */
14045 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14048 {
14052 }
14053 }
14057 {
14063 {
14064 tree op00type;
14068 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14071 {
14073 unsigned HOST_WIDE_INT max_offset
14078 {
14085 }
14086 }
14087 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14090 {
14094 }
14095 /* ((foo *)&fooarray)[1] => fooarray[1] */
14098 {
14108 }
14109 }
14110 }
14112 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14115 && (!in_gimple_form
14117 {
14118 tree type_domain;
14128 NULL_TREE);
14129 }
14132 }
14134 /* Builds an expression for an indirection through T, simplifying some
14135 cases. */
14137 tree
14139 {
14147 }
14149 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14151 tree
14153 {
14158 else
14160 }
14162 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14163 whose result is ignored. The type of the returned tree need not be
14164 the same as the original expression. */
14166 tree
14168 {
14174 {
14185 else
14191 {
14207 }
14212 }
14213 }
14215 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14217 tree
14219 {
14225 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14226 have to do anything. Only do this when we are not given a const,
14227 because in that case, this check is more expensive than just
14228 doing it. */
14230 {
14235 }
14237 /* If divisor is a power of two, simplify this to bit manipulation. */
14239 {
14241 {
14255 }
14256 else
14257 {
14258 tree t;
14264 }
14265 }
14266 else
14267 {
14272 }
14275 }
14277 /* Likewise, but round down. */
14279 tree
14281 {
14288 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14289 have to do anything. Only do this when we are not given a const,
14290 because in that case, this check is more expensive than just
14291 doing it. */
14293 {
14298 }
14300 /* If divisor is a power of two, simplify this to bit manipulation. */
14302 {
14303 tree t;
14307 }
14308 else
14309 {
14314 }
14317 }
14319 /* Returns the pointer to the base of the object addressed by EXP and
14320 extracts the information about the offset of the access, storing it
14321 to PBITPOS and POFFSET. */
14323 static tree
14326 {
14327 tree core;
14328 machine_mode mode;
14330 HOST_WIDE_INT bitsize;
14334 {
14339 }
14341 {
14347 {
14352 {
14355 }
14356 }
14357 }
14358 else
14359 {
14363 }
14366 }
14368 /* Returns true if addresses of E1 and E2 differ by a constant, false
14369 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14371 bool
14373 {
14387 {
14397 }
14399 {
14400 /* If only one of the offsets is non-constant, the difference cannot
14401 be a constant. */
14403 }
14404 else
14409 }
14411 /* Return OFF converted to a pointer offset type suitable as offset for
14412 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14413 tree
14415 {
14417 }
14419 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14420 tree
14422 {
14425 }
14427 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14428 tree
14430 {
14433 }
14435 /* Return a char pointer for a C string if it is a string constant
14436 or sum of string constant and integer constant. We only support
14437 string constants properly terminated with '\0' character.
14438 If STRLEN is a valid pointer, length (including terminating character)
14439 of returned string is stored to the argument. */
14443 {
14444 tree offset_node;
14455 {
14458 else
14460 }
14465 /* Support only properly null-terminated strings. */
14474 }
14476 #if CHECKING_P
14480 /* Helper functions for writing tests of folding trees. */
14482 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14484 static void
14486 tree constant)
14487 {
14489 }
14491 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14492 wrapping WRAPPED_EXPR. */
14494 static void
14496 tree wrapped_expr)
14497 {
14502 }
14504 /* Verify that various arithmetic binary operations are folded
14505 correctly. */
14507 static void
14509 {
14515 /* Addition. */
14516 /* 1 <-- (0 + 1) */
14518 one);
14520 one);
14522 /* (nonlvalue)x <-- (x + 0) */
14524 x);
14526 /* Subtraction. */
14527 /* 0 <-- (x - x) */
14529 zero);
14531 x);
14533 /* Multiplication. */
14534 /* 0 <-- (x * 0) */
14536 zero);
14538 /* (nonlvalue)x <-- (x * 1) */
14540 x);
14541 }
14543 /* Verify that various binary operations on vectors are folded
14544 correctly. */
14546 static void
14548 {
14554 /* Verify equality tests that return a scalar boolean result. */
14560 }
14562 /* Run all of the selftests within this file. */
14564 void
14566 {
14569 }