| blob | f6d5af43b33a8141fbb93bcae537eebed6959a6c |
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. */
6296 /* If these are the same operation types, we can associate them
6297 assuming no overflow. */
6299 {
6314 }
6316 /* If these operations "cancel" each other, we have the main
6317 optimizations of this pass, which occur when either constant is a
6318 multiple of the other, in which case we replace this with either an
6319 operation or CODE or TCODE.
6321 If we have an unsigned type, we cannot do this since it will change
6322 the result if the original computation overflowed. */
6329 {
6331 {
6338 }
6340 {
6347 }
6348 }
6353 }
6356 }
6357 \f
6358 /* Return a node which has the indicated constant VALUE (either 0 or
6359 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6360 and is of the indicated TYPE. */
6362 tree
6364 {
6373 else
6375 }
6378 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6379 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6380 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6381 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6382 COND is the first argument to CODE; otherwise (as in the example
6383 given here), it is the second argument. TYPE is the type of the
6384 original expression. Return NULL_TREE if no simplification is
6385 possible. */
6387 static tree
6392 {
6402 {
6406 /* If this operand throws an expression, then it does not make
6407 sense to try to perform a logical or arithmetic operation
6408 involving it. */
6413 }
6416 {
6421 }
6422 else
6423 /* Detect the case of mixing vector and scalar types - bail out. */
6429 /* This transformation is only worthwhile if we don't have to wrap ARG
6430 in a SAVE_EXPR and the operation can be simplified without recursing
6431 on at least one of the branches once its pushed inside the COND_EXPR. */
6440 {
6444 else
6446 }
6448 {
6452 else
6454 }
6456 /* Check that we have simplified at least one of the branches. */
6461 }
6463 \f
6464 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6466 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6467 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6468 ADDEND is the same as X.
6470 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6471 and finite. The problematic cases are when X is zero, and its mode
6472 has signed zeros. In the case of rounding towards -infinity,
6473 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6474 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6476 bool
6478 {
6482 /* Don't allow the fold with -fsignaling-nans. */
6486 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6490 /* In a vector or complex, we would need to check the sign of all zeros. */
6494 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6498 /* The mode has signed zeros, and we have to honor their sign.
6499 In this situation, there is only one case we can return true for.
6500 X - 0 is the same as X unless rounding towards -infinity is
6501 supported. */
6503 }
6505 /* Subroutine of fold() that optimizes comparisons of a division by
6506 a nonzero integer constant against an integer constant, i.e.
6507 X/C1 op C2.
6509 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6510 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6511 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6513 The function returns the constant folded tree if a simplification
6514 can be made, and NULL_TREE otherwise. */
6516 static tree
6519 {
6527 /* We have to do this the hard way to detect unsigned overflow.
6528 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6534 {
6539 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6543 }
6545 {
6549 {
6568 }
6569 }
6570 else
6571 {
6572 /* A negative divisor reverses the relational operators. */
6578 {
6597 }
6598 }
6601 {
6622 {
6625 }
6630 {
6633 }
6638 {
6641 }
6646 {
6649 }
6654 }
6657 }
6660 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6661 equality/inequality test, then return a simplified form of the test
6662 using a sign testing. Otherwise return NULL. TYPE is the desired
6663 result type. */
6665 static tree
6668 tree result_type)
6669 {
6670 /* If this is testing a single bit, we can optimize the test. */
6674 {
6675 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6676 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6680 /* This is only a win if casting to a signed type is cheap,
6681 i.e. when arg00's type is not a partial mode. */
6684 {
6687 result_type,
6690 }
6691 }
6694 }
6696 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6697 equality/inequality test, then return a simplified form of
6698 the test using shifts and logical operations. Otherwise return
6699 NULL. TYPE is the desired result type. */
6701 tree
6704 {
6705 /* If this is testing a single bit, we can optimize the test. */
6709 {
6718 /* First, see if we can fold the single bit test into a sign-bit
6719 test. */
6721 result_type);
6725 /* Otherwise we have (A & C) != 0 where C is a single bit,
6726 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6727 Similarly for (A & C) == 0. */
6729 /* If INNER is a right shift of a constant and it plus BITNUM does
6730 not overflow, adjust BITNUM and INNER. */
6736 {
6739 }
6741 /* If we are going to be able to omit the AND below, we must do our
6742 operations as unsigned. If we must use the AND, we have a choice.
6743 Normally unsigned is faster, but for some machines signed is. */
6761 /* Put the AND last so it can combine with more things. */
6764 /* Make sure to return the proper type. */
6768 }
6770 }
6772 /* Test whether it is preferable two swap two operands, ARG0 and
6773 ARG1, for example because ARG0 is an integer constant and ARG1
6774 isn't. */
6776 bool
6778 {
6792 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6793 for commutative and comparison operators. Ensuring a canonical
6794 form allows the optimizers to find additional redundancies without
6795 having to explicitly check for both orderings. */
6801 /* Put SSA_NAMEs last. */
6807 /* Put variables last. */
6814 }
6817 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6818 means A >= Y && A != MAX, but in this case we know that
6819 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6821 static tree
6823 {
6830 else
6839 {
6842 }
6844 {
6847 }
6848 else
6855 {
6856 /* Convert the pointer types into integer before taking the difference. */
6860 }
6861 else
6868 }
6870 /* Fold a sum or difference of at least one multiplication.
6871 Returns the folded tree or NULL if no simplification could be made. */
6873 static tree
6876 {
6880 /* (A * C) +- (B * C) -> (A+-B) * C.
6881 (A * C) +- A -> A * (C+-1).
6882 We are most concerned about the case where C is a constant,
6883 but other combinations show up during loop reduction. Since
6884 it is not difficult, try all four possibilities. */
6887 {
6890 }
6892 {
6895 }
6896 else
6897 {
6898 /* We cannot generate constant 1 for fract. */
6903 }
6905 {
6908 }
6910 {
6912 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6913 the purpose of this canonicalization. */
6917 {
6920 }
6921 else
6923 }
6924 else
6925 {
6926 /* We cannot generate constant 1 for fract. */
6931 }
6943 /* No identical multiplicands; see if we can find a common
6944 power-of-two factor in non-power-of-two multiplies. This
6945 can help in multi-dimensional array access. */
6948 {
6951 tree maybe_same;
6955 /* Move min of absolute values to int11. */
6957 {
6962 }
6963 else
6967 /* The remainder should not be a constant, otherwise we
6968 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6969 increased the number of multiplications necessary. */
6971 {
6979 }
6980 }
6990 }
6992 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6993 specified by EXPR into the buffer PTR of length LEN bytes.
6994 Return the number of bytes placed in the buffer, or zero
6995 upon failure. */
6997 static int
6999 {
7013 {
7015 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7016 number of bytes. */
7020 {
7027 else
7029 }
7030 else
7035 }
7037 }
7040 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7041 specified by EXPR into the buffer PTR of length LEN bytes.
7042 Return the number of bytes placed in the buffer, or zero
7043 upon failure. */
7045 static int
7047 {
7051 FIXED_VALUE_TYPE value;
7067 }
7070 /* Subroutine of native_encode_expr. Encode the REAL_CST
7071 specified by EXPR into the buffer PTR of length LEN bytes.
7072 Return the number of bytes placed in the buffer, or zero
7073 upon failure. */
7075 static int
7077 {
7083 /* There are always 32 bits in each long, no matter the size of
7084 the hosts long. We handle floating point representations with
7085 up to 192 bits. */
7099 {
7104 {
7111 else
7113 }
7114 else
7115 {
7118 {
7119 /* Reverse bytes within each long, or within the entire float
7120 if it's smaller than a long (for HFmode). */
7123 }
7124 }
7129 }
7131 }
7133 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7134 specified by EXPR into the buffer PTR of length LEN bytes.
7135 Return the number of bytes placed in the buffer, or zero
7136 upon failure. */
7138 static int
7140 {
7142 tree part;
7157 }
7160 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7161 specified by EXPR into the buffer PTR of length LEN bytes.
7162 Return the number of bytes placed in the buffer, or zero
7163 upon failure. */
7165 static int
7167 {
7177 {
7179 {
7182 }
7193 }
7195 }
7198 /* Subroutine of native_encode_expr. Encode the STRING_CST
7199 specified by EXPR into the buffer PTR of length LEN bytes.
7200 Return the number of bytes placed in the buffer, or zero
7201 upon failure. */
7203 static int
7205 {
7207 HOST_WIDE_INT total_bytes;
7221 {
7224 {
7227 }
7230 }
7231 else
7234 }
7237 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7238 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7239 buffer PTR of length LEN bytes. If OFF is not -1 then start
7240 the encoding at byte offset OFF and encode at most LEN bytes.
7241 Return the number of bytes placed in the buffer, or zero upon failure. */
7243 int
7245 {
7246 /* We don't support starting at negative offset and -1 is special. */
7251 {
7272 }
7273 }
7276 /* Subroutine of native_interpret_expr. Interpret the contents of
7277 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7278 If the buffer cannot be interpreted, return NULL_TREE. */
7280 static tree
7282 {
7292 }
7295 /* Subroutine of native_interpret_expr. Interpret the contents of
7296 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7297 If the buffer cannot be interpreted, return NULL_TREE. */
7299 static tree
7301 {
7303 double_int result;
7304 FIXED_VALUE_TYPE fixed_value;
7314 }
7317 /* Subroutine of native_interpret_expr. Interpret the contents of
7318 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7319 If the buffer cannot be interpreted, return NULL_TREE. */
7321 static tree
7323 {
7327 /* There are always 32 bits in each long, no matter the size of
7328 the hosts long. We handle floating point representations with
7329 up to 192 bits. */
7330 REAL_VALUE_TYPE r;
7341 {
7342 /* Both OFFSET and BYTE index within a long;
7343 bitpos indexes the whole float. */
7346 {
7353 else
7355 }
7356 else
7357 {
7360 {
7361 /* Reverse bytes within each long, or within the entire float
7362 if it's smaller than a long (for HFmode). */
7365 }
7366 }
7370 }
7374 }
7377 /* Subroutine of native_interpret_expr. Interpret the contents of
7378 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7379 If the buffer cannot be interpreted, return NULL_TREE. */
7381 static tree
7383 {
7398 }
7401 /* Subroutine of native_interpret_expr. Interpret the contents of
7402 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7403 If the buffer cannot be interpreted, return NULL_TREE. */
7405 static tree
7407 {
7420 {
7425 }
7427 }
7430 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7431 the buffer PTR of length LEN as a constant of type TYPE. For
7432 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7433 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7434 return NULL_TREE. */
7436 tree
7438 {
7440 {
7462 }
7463 }
7465 /* Returns true if we can interpret the contents of a native encoding
7466 as TYPE. */
7468 static bool
7470 {
7472 {
7485 }
7486 }
7488 /* Return true iff a constant of type TYPE is accepted by
7489 native_encode_expr. */
7491 bool
7493 {
7495 {
7505 }
7506 }
7508 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7509 TYPE at compile-time. If we're unable to perform the conversion
7510 return NULL_TREE. */
7512 static tree
7514 {
7515 /* We support up to 512-bit values (for V8DFmode). */
7519 /* Check that the host and target are sane. */
7528 }
7530 /* Build an expression for the address of T. Folds away INDIRECT_REF
7531 to avoid confusing the gimplify process. */
7533 tree
7535 {
7536 /* The size of the object is not relevant when talking about its address. */
7541 {
7546 }
7556 {
7561 }
7562 else
7566 }
7568 /* Build an expression for the address of T. */
7570 tree
7572 {
7576 }
7578 /* Fold a unary expression of code CODE and type TYPE with operand
7579 OP0. Return the folded expression if folding is successful.
7580 Otherwise, return NULL_TREE. */
7582 tree
7584 {
7585 tree tem;
7586 tree arg0;
7594 {
7597 {
7598 /* Don't use STRIP_NOPS, because signedness of argument type
7599 matters. */
7601 }
7602 else
7603 {
7604 /* Strip any conversions that don't change the mode. This
7605 is safe for every expression, except for a comparison
7606 expression because its signedness is derived from its
7607 operands.
7609 Note that this is done as an internal manipulation within
7610 the constant folder, in order to find the simplest
7611 representation of the arguments so that their form can be
7612 studied. In any cases, the appropriate type conversions
7613 should be put back in the tree that will get out of the
7614 constant folder. */
7616 }
7619 {
7622 {
7626 }
7627 }
7628 }
7635 {
7642 {
7656 /* If this was a conversion, and all we did was to move into
7657 inside the COND_EXPR, bring it back out. But leave it if
7658 it is a conversion from integer to integer and the
7659 result precision is no wider than a word since such a
7660 conversion is cheap and may be optimized away by combine,
7661 while it couldn't if it were outside the COND_EXPR. Then return
7662 so we don't get into an infinite recursion loop taking the
7663 conversion out and then back in. */
7675 && (INTEGRAL_TYPE_P
7688 }
7689 }
7692 {
7698 CASE_CONVERT:
7702 {
7703 /* If we have (type) (a CMP b) and type is an integral type, return
7704 new expression involving the new type. Canonicalize
7705 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7706 non-integral type.
7707 Do not fold the result as that would not simplify further, also
7708 folding again results in recursions. */
7718 }
7720 /* Handle (T *)&A.B.C for A being of type T and B and C
7721 living at offset zero. This occurs frequently in
7722 C++ upcasting and then accessing the base. */
7726 {
7728 tree offset;
7729 machine_mode mode;
7731 tree base
7735 /* If the reference was to a (constant) zero offset, we can use
7736 the address of the base if it has the same base type
7737 as the result type and the pointer type is unqualified. */
7744 }
7748 /* Detect assigning a bitfield. */
7750 && DECL_BIT_FIELD
7752 {
7753 /* Don't leave an assignment inside a conversion
7754 unless assigning a bitfield. */
7756 /* First do the assignment, then return converted constant. */
7761 }
7763 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7764 constants (if x has signed type, the sign bit cannot be set
7765 in c). This folds extension into the BIT_AND_EXPR.
7766 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7767 very likely don't have maximal range for their precision and this
7768 transformation effectively doesn't preserve non-maximal ranges. */
7772 {
7783 <= HOST_BITS_PER_WIDE_INT
7785 {
7789 cst &= HOST_WIDE_INT_M1U
7793 && !flag_syntax_only
7796 {
7800 }
7801 }
7803 {
7808 }
7809 }
7811 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7812 cast (T1)X will fold away. We assume that this happens when X itself
7813 is a cast. */
7817 {
7821 return fold_build_pointer_plus_loc
7823 }
7825 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7826 of the same precision, and X is an integer type not narrower than
7827 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7833 {
7839 }
7841 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7842 type of X and Y (integer types only). */
7847 {
7848 /* Be careful not to introduce new overflows. */
7849 tree mult_type;
7852 else
7856 {
7863 }
7864 }
7870 {
7877 }
7888 /* Convert fabs((double)float) into (double)fabsf(float). */
7891 {
7897 targ0));
7898 }
7902 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7921 /* Note that the operand of this must be an int
7922 and its values must be 0 or 1.
7923 ("true" is a fixed value perhaps depending on the language,
7924 but we don't handle values other than 1 correctly yet.) */
7931 /* Fold *&X to X if X is an lvalue. */
7933 {
7940 }
7946 }
7949 /* If the operation was a conversion do _not_ mark a resulting constant
7950 with TREE_OVERFLOW if the original constant was not. These conversions
7951 have implementation defined behavior and retaining the TREE_OVERFLOW
7952 flag here would confuse later passes such as VRP. */
7953 tree
7956 {
7965 }
7967 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7968 operands OP0 and OP1. LOC is the location of the resulting expression.
7969 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7970 Return the folded expression if folding is successful. Otherwise,
7971 return NULL_TREE. */
7972 static tree
7975 {
7976 tree tem;
7978 /* We only do these simplifications if we are optimizing. */
7982 /* Check for things like (A || B) && (A || C). We can convert this
7983 to A || (B && C). Note that either operator can be any of the four
7984 truth and/or operations and the transformation will still be
7985 valid. Also note that we only care about order for the
7986 ANDIF and ORIF operators. If B contains side effects, this
7987 might change the truth-value of A. */
7994 {
8014 /* This case if tricky because we must either have commutative
8015 operators or else A10 must not have side-effects. */
8021 a01);
8022 }
8024 /* See if we can build a range comparison. */
8030 {
8034 }
8038 {
8042 }
8044 /* Check for the possibility of merging component references. If our
8045 lhs is another similar operation, try to merge its rhs with our
8046 rhs. Then try to merge our lhs and rhs. */
8060 {
8067 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8068 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8069 We don't want to pack more than two leafs to a non-IF AND/OR
8070 expression.
8071 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8072 equal to IF-CODE, then we don't want to add right-hand operand.
8073 If the inner right-hand side of left-hand operand has
8074 side-effects, or isn't simple, then we can't add to it,
8075 as otherwise we might destroy if-sequence. */
8078 /* Needed for sequence points to handle trappings, and
8079 side-effects. */
8081 {
8083 arg1);
8085 tem);
8086 }
8087 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8088 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8091 /* Needed for sequence points to handle trappings, and
8092 side-effects. */
8094 {
8099 }
8100 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8101 into (A OR B).
8102 For sequence point consistancy, we need to check for trapping,
8103 and side-effects. */
8107 }
8110 }
8112 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8113 by changing CODE to reduce the magnitude of constants involved in
8114 ARG0 of the comparison.
8115 Returns a canonicalized comparison tree if a simplification was
8116 possible, otherwise returns NULL_TREE.
8117 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8118 valid if signed overflow is undefined. */
8120 static tree
8124 {
8129 /* Match A +- CST code arg1. We can change this only if overflow
8130 is undefined. */
8133 /* In principle pointers also have undefined overflow behavior,
8134 but that causes problems elsewhere. */
8141 /* Identify the constant in arg0 and its sign. */
8145 /* Overflowed constants and zero will cause problems. */
8150 /* See if we can reduce the magnitude of the constant in
8151 arg0 by changing the comparison code. */
8152 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8156 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8160 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8164 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8168 else
8172 /* Now build the constant reduced in magnitude. But not if that
8173 would produce one outside of its types range. */
8189 }
8191 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8192 overflow further. Try to decrease the magnitude of constants involved
8193 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8194 and put sole constants at the second argument position.
8195 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8197 static tree
8200 {
8201 tree t;
8206 /* Try canonicalization by simplifying arg0. */
8211 {
8215 }
8217 /* Try canonicalization by simplifying arg1 using the swapped
8218 comparison. */
8226 }
8228 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8229 space. This is used to avoid issuing overflow warnings for
8230 expressions like &p->x which can not wrap. */
8232 static bool
8234 {
8241 wide_int wi_offset;
8247 else
8263 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8264 array. */
8266 {
8267 HOST_WIDE_INT base_size;
8272 }
8275 }
8277 /* Return a positive integer when the symbol DECL is known to have
8278 a nonzero address, zero when it's known not to (e.g., it's a weak
8279 symbol), and a negative integer when the symbol is not yet in the
8280 symbol table and so whether or not its address is zero is unknown.
8281 For function local objects always return positive integer. */
8282 static int
8284 {
8289 /* Function local objects are never NULL. */
8297 }
8299 /* Subroutine of fold_binary. This routine performs all of the
8300 transformations that are common to the equality/inequality
8301 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8302 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8303 fold_binary should call fold_binary. Fold a comparison with
8304 tree code CODE and type TYPE with operands OP0 and OP1. Return
8305 the folded comparison or NULL_TREE. */
8307 static tree
8310 {
8320 /* For comparisons of pointers we can decompose it to a compile time
8321 comparison of the base objects and the offsets into the object.
8322 This requires at least one operand being an ADDR_EXPR or a
8323 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8329 {
8332 machine_mode mode;
8336 /* Get base and offset for the access. Strip ADDR_EXPR for
8337 get_inner_reference, but put it back by stripping INDIRECT_REF
8338 off the base object if possible. indirect_baseN will be true
8339 if baseN is not an address but refers to the object itself. */
8342 {
8343 base0
8349 else
8351 }
8353 {
8357 {
8358 base0
8364 else
8366 }
8369 else
8373 {
8379 {
8382 }
8383 }
8384 }
8388 {
8389 base1
8395 else
8397 }
8399 {
8403 {
8404 base1
8410 else
8412 }
8415 else
8419 {
8425 {
8428 }
8429 }
8430 }
8432 /* If we have equivalent bases we might be able to simplify. */
8436 {
8437 /* We can fold this expression to a constant if the non-constant
8438 offset parts are equal. */
8442 && (equality_code
8443 || (indirect_base0
8447 {
8453 "occur when comparing P +- C1 with "
8455 WARN_STRICT_OVERFLOW_CONDITIONAL);
8458 {
8472 }
8473 }
8474 /* We can simplify the comparison to a comparison of the variable
8475 offset parts if the constant offset parts are equal.
8476 Be careful to use signed sizetype here because otherwise we
8477 mess with array offsets in the wrong way. This is possible
8478 because pointer arithmetic is restricted to retain within an
8479 object and overflow on pointer differences is undefined as of
8480 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8482 && (equality_code
8483 || (indirect_base0
8486 {
8487 /* By converting to signed sizetype we cover middle-end pointer
8488 arithmetic which operates on unsigned pointer types of size
8489 type size and ARRAY_REF offsets which are properly sign or
8490 zero extended from their type in case it is narrower than
8491 sizetype. */
8494 else
8498 else
8505 "occur when comparing P +- C1 with "
8507 WARN_STRICT_OVERFLOW_COMPARISON);
8510 }
8511 }
8512 /* For equal offsets we can simplify to a comparison of the
8513 base addresses. */
8515 && (indirect_base0
8517 && (indirect_base1
8522 {
8528 }
8529 /* Comparison between an ordinary (non-weak) symbol and a null
8530 pointer can be eliminated since such symbols must have a non
8531 null address. In C, relational expressions between pointers
8532 to objects and null pointers are undefined. The results
8533 below follow the C++ rules with the additional property that
8534 every object pointer compares greater than a null pointer.
8535 */
8538 /* Avoid folding references to struct members at offset 0 to
8539 prevent tests like '&ptr->firstmember == 0' from getting
8540 eliminated. When ptr is null, although the -> expression
8541 is strictly speaking invalid, GCC retains it as a matter
8542 of QoI. See PR c/44555. */
8545 && indirect_base0
8546 /* The caller guarantees that when one of the arguments is
8547 constant (i.e., null in this case) it is second. */
8549 {
8551 {
8562 }
8563 }
8564 }
8566 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8567 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8568 the resulting offset is smaller in absolute value than the
8569 original one and has the same sign. */
8578 {
8583 tree cst;
8585 "occur when combining constants around "
8588 /* Put the constant on the side where it doesn't overflow and is
8589 of lower absolute value and of same sign than before. */
8596 {
8599 variable1,
8603 }
8611 {
8617 variable2);
8618 }
8619 }
8625 /* If we are comparing an expression that just has comparisons
8626 of two integer values, arithmetic expressions of those comparisons,
8627 and constants, we can simplify it. There are only three cases
8628 to check: the two values can either be equal, the first can be
8629 greater, or the second can be greater. Fold the expression for
8630 those three values. Since each value must be 0 or 1, we have
8631 eight possibilities, each of which corresponds to the constant 0
8632 or 1 or one of the six possible comparisons.
8634 This handles common cases like (a > b) == 0 but also handles
8635 expressions like ((x > y) - (y > x)) > 0, which supposedly
8636 occur in macroized code. */
8639 {
8644 /* Don't handle degenerate cases here; they should already
8645 have been handled anyway. */
8654 {
8658 /* We can't just pass T to eval_subst in case cval1 or cval2
8659 was the same as ARG1. */
8661 tree high_result
8665 arg1);
8666 tree equal_result
8670 arg1);
8671 tree low_result
8675 arg1);
8677 /* All three of these results should be 0 or 1. Confirm they are.
8678 Then use those values to select the proper code to use. */
8683 {
8684 /* Make a 3-bit mask with the high-order bit being the
8685 value for `>', the next for '=', and the low for '<'. */
8689 {
8691 /* Always false. */
8712 /* Always true. */
8714 }
8717 {
8721 }
8723 }
8724 }
8725 }
8727 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8728 into a single range test. */
8735 {
8739 }
8742 }
8745 /* Subroutine of fold_binary. Optimize complex multiplications of the
8746 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8747 argument EXPR represents the expression "z" of type TYPE. */
8749 static tree
8751 {
8756 {
8759 }
8761 {
8764 }
8765 else
8766 {
8770 }
8779 }
8782 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8783 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8785 static bool
8787 {
8791 {
8794 }
8796 {
8802 else
8804 }
8805 else
8811 }
8813 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8814 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8815 NULL_TREE otherwise. */
8817 static tree
8819 {
8836 {
8840 }
8843 {
8849 }
8850 else
8852 }
8854 /* Try to fold a pointer difference of type TYPE two address expressions of
8855 array references AREF0 and AREF1 using location LOC. Return a
8856 simplified expression for the difference or NULL_TREE. */
8858 static tree
8861 {
8866 /* If the bases are array references as well, recurse. If the bases
8867 are pointer indirections compute the difference of the pointers.
8868 If the bases are equal, we are set. */
8871 && (base_offset
8875 && (base_offset
8881 {
8887 base_offset,
8890 }
8892 }
8894 /* If the real or vector real constant CST of type TYPE has an exact
8895 inverse, return it, else return NULL. */
8897 tree
8899 {
8900 REAL_VALUE_TYPE r;
8902 machine_mode mode;
8906 {
8922 {
8927 }
8933 }
8934 }
8936 /* Mask out the tz least significant bits of X of type TYPE where
8937 tz is the number of trailing zeroes in Y. */
8938 static wide_int
8940 {
8945 }
8947 /* Return true when T is an address and is known to be nonzero.
8948 For floating point we further ensure that T is not denormal.
8949 Similar logic is present in nonzero_address in rtlanal.h.
8951 If the return value is based on the assumption that signed overflow
8952 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8953 change *STRICT_OVERFLOW_P. */
8955 static bool
8957 {
8961 /* Doing something useful for floating point would need more work. */
8967 {
8970 strict_overflow_p);
8976 strict_overflow_p);
8984 }
8987 {
8990 strict_overflow_p);
8998 strict_overflow_p);
9013 strict_overflow_p);
9017 strict_overflow_p);
9020 {
9032 }
9036 }
9038 }
9040 /* Return true when T is an address and is known to be nonzero.
9041 Handle warnings about undefined signed overflow. */
9043 bool
9045 {
9052 "determining that expression is always "
9054 WARN_STRICT_OVERFLOW_MISC);
9056 }
9058 /* Return true if T is known not to be equal to an integer W. */
9060 bool
9062 {
9064 value_range_type rtype;
9066 {
9075 {
9080 }
9085 /* If T has some known zero bits and W has any of those bits set,
9086 then T is known not to be equal to W. */
9094 }
9095 }
9097 /* Fold a binary expression of code CODE and type TYPE with operands
9098 OP0 and OP1. LOC is the location of the resulting expression.
9099 Return the folded expression if folding is successful. Otherwise,
9100 return NULL_TREE. */
9102 tree
9105 {
9120 /* Strip any conversions that don't change the mode. This is
9121 safe for every expression, except for a comparison expression
9122 because its signedness is derived from its operands. So, in
9123 the latter case, only strip conversions that don't change the
9124 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9125 preserved.
9127 Note that this is done as an internal manipulation within the
9128 constant folder, in order to find the simplest representation
9129 of the arguments so that their form can be studied. In any
9130 cases, the appropriate type conversions should be put back in
9131 the tree that will get out of the constant folder. */
9134 {
9137 }
9138 else
9139 {
9142 }
9144 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9145 constant but we can't do arithmetic on them. */
9147 {
9150 {
9154 }
9155 }
9157 /* If this is a commutative operation, and ARG0 is a constant, move it
9158 to ARG1 to reduce the number of tests below. */
9163 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9164 to ARG1 to reduce the number of tests below. */
9173 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9175 First check for cases where an arithmetic operation is applied to a
9176 compound, conditional, or comparison operation. Push the arithmetic
9177 operation inside the compound or conditional to see if any folding
9178 can then be done. Convert comparison to conditional for this purpose.
9179 The also optimizes non-constant cases that used to be done in
9180 expand_expr.
9182 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9183 one of the operands is a comparison and the other is a comparison, a
9184 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9185 code below would make the expression more complex. Change it to a
9186 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9187 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9200 {
9204 boolean_type_node,
9212 }
9216 {
9218 {
9223 tem);
9224 }
9226 {
9231 tem);
9232 }
9237 {
9243 }
9248 {
9254 }
9255 }
9258 {
9260 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9263 {
9269 }
9271 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9274 {
9275 tree base;
9276 HOST_WIDE_INT coffset;
9285 }
9290 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9296 arg1),
9298 arg0)));
9304 {
9305 /* X + (X / CST) * -CST is X % CST. */
9310 {
9319 cst0));
9320 }
9321 }
9323 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9324 one. Make sure the type is not saturating and has the signedness of
9325 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9326 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9333 {
9337 }
9340 {
9341 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9342 (plus (plus (mult) (mult)) (foo)) so that we can
9343 take advantage of the factoring cases below. */
9352 {
9358 else
9371 parg0),
9373 marg)),
9377 return
9383 parg1)));
9384 }
9385 }
9386 else
9387 {
9388 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9389 to __complex__ ( x, y ). This is not the same for SNaNs or
9390 if signed zeros are involved. */
9394 {
9401 {
9405 {
9411 }
9413 {
9419 }
9420 }
9421 }
9429 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9430 We associate floats only if the user has specified
9431 -fassociative-math. */
9435 {
9440 {
9441 tree tree0;
9444 }
9445 }
9446 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9447 We associate floats only if the user has specified
9448 -fassociative-math. */
9452 {
9457 {
9458 tree tree0;
9461 }
9462 }
9463 }
9465 bit_rotate:
9466 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9467 is a rotate of A by C1 bits. */
9468 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9469 is a rotate of A by B bits. */
9470 {
9472 tree rtype;
9481 /* Only create rotates in complete modes. Other cases are not
9482 expanded properly. */
9485 {
9499 {
9503 code0 == LSHIFT_EXPR
9507 }
9509 {
9517 element_precision
9521 return
9524 ? LROTATE_EXPR
9529 }
9531 {
9539 element_precision
9543 return fold_convert_loc
9546 ? LROTATE_EXPR
9550 }
9551 }
9552 }
9554 associate:
9555 /* In most languages, can't associate operations on floats through
9556 parentheses. Rather than remember where the parentheses were, we
9557 don't associate floats at all, unless the user has specified
9558 -fassociative-math.
9559 And, we need to make sure type is not saturating. */
9563 {
9569 /* Split both trees into variables, constants, and literals. Then
9570 associate each group together, the constants with literals,
9571 then the result with variables. This increases the chances of
9572 literals being recombined later and of generating relocatable
9573 expressions for the sum of a constant and literal. */
9579 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9583 /* With undefined overflow prefer doing association in a type
9584 which wraps on overflow, if that is one of the operand types. */
9587 {
9595 }
9597 /* With undefined overflow we can only associate constants with one
9598 variable, and constants whose association doesn't overflow. */
9601 {
9603 {
9609 {
9612 }
9619 {
9622 }
9628 /* The only case we can still associate with two variables
9629 is if they cancel out. */
9633 }
9634 }
9636 /* Only do something if we found more than two objects. Otherwise,
9637 nothing has changed and we risk infinite recursion. */
9643 {
9655 /* Preserve the MINUS_EXPR if the negative part of the literal is
9656 greater than the positive part. Otherwise, the multiplicative
9657 folding code (i.e extract_muldiv) may be fooled in case
9658 unsigned constants are subtracted, like in the following
9659 example: ((X*2 + 4) - 8U)/2. */
9661 {
9665 {
9669 }
9670 else
9671 {
9675 }
9676 }
9678 /* Don't introduce overflows through reassociation. */
9685 {
9687 return
9691 else
9692 {
9695 return
9699 }
9700 }
9703 return
9706 }
9707 }
9712 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9720 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9721 __complex__ ( x, -y ). This is not the same for SNaNs or if
9722 signed zeros are involved. */
9726 {
9733 {
9737 {
9739 arg1r ? arg1r
9744 }
9746 {
9750 arg1i ? arg1i
9753 }
9754 }
9755 }
9757 /* A - B -> A + (-B) if B is easily negatable. */
9761 /* Avoid this transformation if B is a positive REAL_CST. */
9769 /* Fold &a[i] - &a[j] to i-j. */
9774 {
9780 }
9783 && flag_unsafe_math_optimizations
9789 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9790 one. Make sure the type is not saturating and has the signedness of
9791 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9792 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9799 {
9803 }
9809 {
9810 /* Transform x * -C into -x * C if x is easily negatable. */
9824 {
9827 "occur when simplifying "
9829 WARN_STRICT_OVERFLOW_MISC);
9831 }
9833 /* Optimize z * conj(z) for integer complex numbers. */
9840 }
9841 else
9842 {
9843 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9844 This is not the same for NaNs or if signed zeros are
9845 involved. */
9851 {
9854 return
9860 return
9865 }
9867 /* Optimize z * conj(z) for floating point complex numbers.
9868 Guarded by flag_unsafe_math_optimizations as non-finite
9869 imaginary components don't produce scalar results. */
9878 }
9882 /* Canonicalize (X & C1) | C2. */
9886 {
9891 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9899 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9901 {
9904 }
9906 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9907 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9908 mode which allows further optimizations. */
9913 {
9917 {
9920 }
9921 }
9924 {
9929 }
9930 }
9932 /* See if this can be simplified into a rotate first. If that
9933 is unsuccessful continue in the association code. */
9937 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9945 /* See if this can be simplified into a rotate first. If that
9946 is unsuccessful continue in the association code. */
9950 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9955 {
9956 tree tem2;
9963 }
9964 /* Fold ~X & 1 as (X & 1) == 0. */
9968 {
9969 tree tem2;
9976 }
9977 /* Fold !X & 1 as X == 0. */
9980 {
9984 }
9986 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
9987 multiple of 1 << CST. */
9989 {
9996 }
9998 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
9999 bits from CST2. */
10003 {
10011 {
10012 /* Avoid the transform if arg1 is a mask of some
10013 mode which allows further optimizations. */
10020 }
10021 }
10023 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10024 ((A & N) + B) & M -> (A + B) & M
10025 Similarly if (N & M) == 0,
10026 ((A | N) + B) & M -> (A + B) & M
10027 and for - instead of + (or unary - instead of +)
10028 and/or ^ instead of |.
10029 If B is constant and (B & M) == 0, fold into A & M. */
10031 {
10040 {
10043 wide_int cst0;
10045 /* Now we know that arg0 is (C + D) or (C - D) or
10046 -C and arg1 (M) is == (1LL << cst) - 1.
10047 Store C into PMOP[0] and D into PMOP[1]. */
10051 {
10054 }
10061 {
10071 {
10074 }
10077 /* If C or D is of the form (A & N) where
10078 (N & M) == M, or of the form (A | N) or
10079 (A ^ N) where (N & M) == 0, replace it with A. */
10083 /* If C or D is a N where (N & M) == 0, it can be
10084 omitted (assumed 0). */
10092 }
10094 /* Only build anything new if we optimized one or both arguments
10095 above. */
10099 {
10102 {
10103 /* Perform the operations in a type that has defined
10104 overflow behavior. */
10110 }
10115 {
10123 else
10125 }
10128 else
10131 /* TEM is now the new binary +, - or unary - replacement. */
10135 }
10136 }
10137 }
10139 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10142 {
10147 return
10149 }
10154 /* Don't touch a floating-point divide by zero unless the mode
10155 of the constant can represent infinity. */
10161 /* (-A) / (-B) -> A / B */
10173 /* Fall through */
10176 /* Simplify A / (B << N) where A and B are positive and B is
10177 a power of 2, to A >> (N + log2(B)). */
10182 {
10185 {
10193 WARN_STRICT_OVERFLOW_MISC);
10199 }
10200 }
10202 /* Fall through */
10210 /* Convert -A / -B to A / B when the type is signed and overflow is
10211 undefined. */
10215 {
10218 "when distributing negation across "
10220 WARN_STRICT_OVERFLOW_MISC);
10225 }
10229 {
10232 "when distributing negation across "
10234 WARN_STRICT_OVERFLOW_MISC);
10239 }
10241 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10242 operation, EXACT_DIV_EXPR.
10244 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10245 At one time others generated faster code, it's not clear if they do
10246 after the last round to changes to the DIV code in expmed.c. */
10257 {
10261 WARN_STRICT_OVERFLOW_MISC);
10263 }
10275 {
10279 WARN_STRICT_OVERFLOW_MISC);
10281 }
10289 /* Since negative shift count is not well-defined,
10290 don't try to compute it in the compiler. */
10296 /* If we have a rotate of a bit operation with the rotate count and
10297 the second operand of the bit operation both constant,
10298 permute the two operations. */
10304 {
10312 }
10314 /* Two consecutive rotates adding up to the some integer
10315 multiple of the precision of the type can be ignored. */
10330 /* Note that the operands of this must be ints
10331 and their values must be 0 or 1.
10332 ("true" is a fixed value perhaps depending on the language.) */
10333 /* If first arg is constant zero, return it. */
10336 /* FALLTHRU */
10338 /* If either arg is constant true, drop it. */
10342 /* Preserve sequence points. */
10345 /* If second arg is constant zero, result is zero, but first arg
10346 must be evaluated. */
10349 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10350 case will be handled here. */
10354 /* !X && X is always false. */
10358 /* X && !X is always false. */
10363 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10364 means A >= Y && A != MAX, but in this case we know that
10365 A < X <= MAX. */
10369 {
10377 }
10386 /* Note that the operands of this must be ints
10387 and their values must be 0 or true.
10388 ("true" is a fixed value perhaps depending on the language.) */
10389 /* If first arg is constant true, return it. */
10392 /* FALLTHRU */
10394 /* If either arg is constant zero, drop it. */
10398 /* Preserve sequence points. */
10401 /* If second arg is constant true, result is true, but we must
10402 evaluate first arg. */
10405 /* Likewise for first arg, but note this only occurs here for
10406 TRUTH_OR_EXPR. */
10410 /* !X || X is always true. */
10414 /* X || !X is always true. */
10419 /* (X && !Y) || (!X && Y) is X ^ Y */
10422 {
10439 }
10448 /* If the second arg is constant zero, drop it. */
10451 /* If the second arg is constant true, this is a logical inversion. */
10453 {
10456 }
10457 /* Identical arguments cancel to zero. */
10461 /* !X ^ X is always true. */
10466 /* X ^ !X is always true. */
10482 /* bool_var != 1 becomes !bool_var. */
10489 /* bool_var == 0 becomes !bool_var. */
10496 /* !exp != 0 becomes !exp */
10501 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10510 {
10516 }
10518 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10527 {
10533 }
10535 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
10543 code == NE_EXPR
10547 /* Transform comparisons of the form X CMP C - X if C % 2 == 1. */
10555 code == NE_EXPR
10559 /* If this is an EQ or NE comparison with zero and ARG0 is
10560 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10561 two operations, but the latter can be done in one less insn
10562 on machines that have only two-operand insns or on which a
10563 constant cannot be the first operand. */
10566 {
10571 {
10578 arg1);
10579 }
10582 {
10589 arg1);
10590 }
10591 }
10593 /* If this is an NE or EQ comparison of zero against the result of a
10594 signed MOD operation whose second operand is a power of 2, make
10595 the MOD operation unsigned since it is simpler and equivalent. */
10603 {
10613 }
10615 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10616 C1 is a valid shift constant, and C2 is a power of two, i.e.
10617 a single bit. */
10621 == INTEGER_CST
10624 {
10629 /* Check for a valid shift count. */
10631 {
10635 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10636 can be rewritten as (X & (C2 << C1)) != 0. */
10638 {
10643 }
10644 /* Otherwise, for signed (arithmetic) shifts,
10645 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10646 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10650 /* Otherwise, of unsigned (logical) shifts,
10651 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10652 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10653 else
10657 arg000);
10658 }
10659 }
10661 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
10662 Similarly for NE_EXPR. */
10666 {
10670 tree dandnotc
10673 notc);
10677 }
10679 /* If this is a comparison of a field, we may be able to simplify it. */
10682 /* Handle the constant case even without -O
10683 to make sure the warnings are given. */
10685 {
10689 }
10691 /* Optimize comparisons of strlen vs zero to a compare of the
10692 first character of the string vs zero. To wit,
10693 strlen(ptr) == 0 => *ptr == 0
10694 strlen(ptr) != 0 => *ptr != 0
10695 Other cases should reduce to one of these two (or a constant)
10696 due to the return value of strlen being unsigned. */
10699 {
10707 {
10712 }
10713 }
10715 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10716 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10720 {
10725 {
10727 {
10730 }
10733 }
10734 }
10736 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10737 (X & C) == 0 when C is a single bit. */
10742 {
10749 arg1));
10750 }
10752 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10753 constant C is a power of two, i.e. a single bit. */
10760 {
10764 }
10766 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10767 when is C is a power of two, i.e. a single bit. */
10774 {
10780 }
10784 {
10787 }
10789 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10792 {
10800 {
10806 }
10808 {
10814 }
10816 {
10822 }
10824 {
10830 }
10831 }
10835 {
10842 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10843 operand_equal_p guarantees no side-effects so we don't need
10844 to use omit_one_operand on Z. */
10848 arg10));
10852 arg11));
10856 arg10));
10860 arg11));
10862 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10865 {
10871 }
10872 }
10874 /* Attempt to simplify equality/inequality comparisons of complex
10875 values. Only lower the comparison if the result is known or
10876 can be simplified to a single scalar comparison. */
10881 {
10886 {
10889 }
10890 else
10891 {
10894 }
10897 {
10900 }
10901 else
10902 {
10905 }
10909 {
10911 {
10916 }
10917 else
10918 {
10923 }
10924 }
10928 {
10930 {
10935 }
10936 else
10937 {
10942 }
10943 }
10944 }
10956 /* Transform comparisons of the form X +- C CMP X. */
10963 {
10970 else
10973 /* (X - c) > X becomes false. */
10977 {
10981 "occur when assuming that (X - c) > X "
10983 WARN_STRICT_OVERFLOW_ALL);
10985 }
10987 /* Likewise (X + c) < X becomes false. */
10991 {
10995 "occur when assuming that "
10997 WARN_STRICT_OVERFLOW_ALL);
10999 }
11001 /* Convert (X - c) <= X to true. */
11006 {
11010 "occur when assuming that "
11012 WARN_STRICT_OVERFLOW_ALL);
11014 }
11016 /* Convert (X + c) >= X to true. */
11021 {
11025 "occur when assuming that "
11027 WARN_STRICT_OVERFLOW_ALL);
11029 }
11032 {
11033 /* Convert X + c > X and X - c < X to true for integers. */
11037 {
11040 "not occur when assuming that "
11042 WARN_STRICT_OVERFLOW_ALL);
11044 }
11049 {
11052 "not occur when assuming that "
11054 WARN_STRICT_OVERFLOW_ALL);
11056 }
11058 /* Convert X + c <= X and X - c >= X to false for integers. */
11062 {
11065 "not occur when assuming that "
11067 WARN_STRICT_OVERFLOW_ALL);
11069 }
11074 {
11077 "not occur when assuming that "
11079 WARN_STRICT_OVERFLOW_ALL);
11081 }
11082 }
11083 }
11085 /* If we are comparing an ABS_EXPR with a constant, we can
11086 convert all the cases into explicit comparisons, but they may
11087 well not be faster than doing the ABS and one comparison.
11088 But ABS (X) <= C is a range comparison, which becomes a subtraction
11089 and a comparison, and is probably faster. */
11103 /* Convert ABS_EXPR<x> >= 0 to true. */
11110 {
11113 "when simplifying comparison of "
11115 WARN_STRICT_OVERFLOW_CONDITIONAL);
11118 arg0);
11119 }
11121 /* Convert ABS_EXPR<x> < 0 to false. */
11126 {
11129 "when simplifying comparison of "
11131 WARN_STRICT_OVERFLOW_CONDITIONAL);
11134 arg0);
11135 }
11137 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11138 and similarly for >= into !=. */
11148 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11149 otherwise Y might be >= # of bits in X's type and thus e.g.
11150 (unsigned char) (1 << Y) for Y 15 might be 0.
11151 If the cast is widening, then 1 << Y should have unsigned type,
11152 otherwise if Y is number of bits in the signed shift type minus 1,
11153 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11154 31 might be 0xffffffff80000000. */
11165 {
11171 }
11183 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11184 {
11196 }
11201 /* When pedantic, a compound expression can be neither an lvalue
11202 nor an integer constant expression. */
11205 /* Don't let (0, 0) be null pointer constant. */
11211 /* An ASSERT_EXPR should never be passed to fold_binary. */
11217 }
11219 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11220 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11221 of GOTO_EXPR. */
11223 static tree
11225 {
11227 {
11234 /* fall through */
11238 }
11239 }
11241 /* Return whether the sub-tree ST contains a label which is accessible from
11242 outside the sub-tree. */
11244 static bool
11246 {
11247 return
11249 }
11251 /* Fold a ternary expression of code CODE and type TYPE with operands
11252 OP0, OP1, and OP2. Return the folded expression if folding is
11253 successful. Otherwise, return NULL_TREE. */
11255 tree
11258 {
11259 tree tem;
11266 /* If this is a commutative operation, and OP0 is a constant, move it
11267 to OP1 to reduce the number of tests below. */
11276 /* Strip any conversions that don't change the mode. This is safe
11277 for every expression, except for a comparison expression because
11278 its signedness is derived from its operands. So, in the latter
11279 case, only strip conversions that don't change the signedness.
11281 Note that this is done as an internal manipulation within the
11282 constant folder, in order to find the simplest representation of
11283 the arguments so that their form can be studied. In any cases,
11284 the appropriate type conversions should be put back in the tree
11285 that will get out of the constant folder. */
11287 {
11290 }
11293 {
11296 }
11299 {
11302 }
11305 {
11309 {
11315 }
11320 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11321 so all simple results must be passed through pedantic_non_lvalue. */
11323 {
11326 /* Only optimize constant conditions when the selected branch
11327 has the same type as the COND_EXPR. This avoids optimizing
11328 away "c ? x : throw", where the throw has a void type.
11329 Avoid throwing away that operand which contains label. */
11336 }
11338 {
11343 {
11348 {
11356 }
11360 }
11361 }
11363 /* If we have A op B ? A : C, we may be able to convert this to a
11364 simpler expression, depending on the operation and the values
11365 of B and C. Signed zeros prevent all of these transformations,
11366 for reasons given above each one.
11368 Also try swapping the arguments and inverting the conditional. */
11373 {
11377 }
11381 op2,
11384 {
11388 {
11392 }
11393 }
11395 /* If the second operand is simpler than the third, swap them
11396 since that produces better jump optimization results. */
11399 {
11401 /* See if this can be inverted. If it can't, possibly because
11402 it was a floating-point inequality comparison, don't do
11403 anything. */
11407 }
11409 /* Convert A ? 1 : 0 to simply A. */
11414 /* If we try to convert OP0 to our type, the
11415 call to fold will try to move the conversion inside
11416 a COND, which will recurse. In that case, the COND_EXPR
11417 is probably the best choice, so leave it alone. */
11421 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11422 over COND_EXPR in cases such as floating point comparisons. */
11431 arg0)));
11433 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11438 {
11439 /* sign_bit_p looks through both zero and sign extensions,
11440 but for this optimization only sign extensions are
11441 usable. */
11444 {
11447 {
11450 }
11452 }
11453 /* sign_bit_p only checks ARG1 bits within A's precision.
11454 If <sign bit of A> has wider type than A, bits outside
11455 of A's precision in <sign bit of A> need to be checked.
11456 If they are all 0, this optimization needs to be done
11457 in unsigned A's type, if they are all 1 in signed A's type,
11458 otherwise this can't be done. */
11464 {
11466 tree tem_type;
11479 {
11482 }
11484 {
11487 }
11488 else
11490 }
11493 return
11499 arg1)));
11500 }
11502 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11503 already handled above. */
11508 {
11518 op1);
11519 }
11521 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11522 is probably obsolete because the first operand should be a
11523 truth value (that's why we have the two cases above), but let's
11524 leave it in until we can confirm this for all front-ends. */
11536 /* Disable the transformations below for vectors, since
11537 fold_binary_op_with_conditional_arg may undo them immediately,
11538 yielding an infinite loop. */
11542 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11551 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11556 {
11558 /* Only perform transformation if ARG0 is easily inverted. */
11562 ? BIT_IOR_EXPR
11565 op1);
11566 }
11568 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11573 {
11575 /* Only perform transformation if ARG0 is easily inverted. */
11581 op2);
11582 }
11584 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11596 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11597 of fold_ternary on them. */
11605 {
11615 {
11620 {
11628 }
11629 }
11630 }
11632 /* On constants we can use native encode/interpret to constant
11633 fold (nearly) all BIT_FIELD_REFs. */
11637 {
11640 /* Limit us to a reasonable amount of work. To relax the
11641 other limitations we need bit-shifting of the buffer
11642 and rounding up the size. */
11646 {
11648 unsigned HOST_WIDE_INT len
11653 {
11658 }
11659 }
11660 }
11665 /* For integers we can decompose the FMA if possible. */
11677 {
11693 {
11698 /* Make sure that the perm value is in an acceptable
11699 range. */
11708 else
11713 }
11716 {
11721 }
11726 {
11731 }
11737 {
11741 }
11746 /* Some targets are deficient and fail to expand a single
11747 argument permutation while still allowing an equivalent
11748 2-argument version. */
11752 {
11755 }
11758 {
11765 }
11769 }
11773 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11776 {
11782 wide_int tem2
11786 }
11791 {
11793 unsigned HOST_WIDE_INT elsize
11796 {
11800 else
11801 {
11807 }
11808 }
11809 }
11815 }
11817 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11818 of an array (or vector). */
11820 tree
11822 {
11827 {
11830 {
11831 /* Static constructors for variably sized objects makes no sense. */
11835 }
11836 }
11847 offset_int max_index;
11852 {
11853 /* Array constructor might explicitly set index, or specify a range,
11854 or leave index NULL meaning that it is next index after previous
11855 one. */
11857 {
11860 else
11861 {
11865 }
11866 }
11867 else
11868 {
11874 }
11876 /* Do we have match? */
11880 }
11882 }
11884 /* Perform constant folding and related simplification of EXPR.
11885 The related simplifications include x*1 => x, x*0 => 0, etc.,
11886 and application of the associative law.
11887 NOP_EXPR conversions may be removed freely (as long as we
11888 are careful not to change the type of the overall expression).
11889 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11890 but we can constant-fold them if they have constant operands. */
11892 #ifdef ENABLE_FOLD_CHECKING
11893 # define fold(x) fold_1 (x)
11895 static
11896 #endif
11897 tree
11899 {
11903 tree tem;
11906 /* Return right away if a constant. */
11910 /* CALL_EXPR-like objects with variable numbers of operands are
11911 treated specially. */
11913 {
11915 {
11918 }
11920 }
11923 {
11928 {
11946 }
11947 }
11950 {
11952 {
11959 {
11964 }
11967 }
11969 /* Return a VECTOR_CST if possible. */
11971 {
11977 tree val;
11983 }
11991 }
11993 #ifdef ENABLE_FOLD_CHECKING
11994 #undef fold
12001 /* When --enable-checking=fold, compute a digest of expr before
12002 and after actual fold call to see if fold did not accidentally
12003 change original expr. */
12005 tree
12007 {
12008 tree ret;
12028 }
12030 void
12032 {
12043 }
12045 static void
12047 {
12049 }
12051 static void
12054 {
12060 recursive_label:
12070 {
12071 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12076 }
12084 {
12085 /* Allow these fields to be modified. */
12086 tree tmp;
12095 {
12098 }
12099 }
12110 {
12113 {
12128 }
12132 {
12145 }
12162 {
12168 }
12171 {
12173 {
12176 }
12178 }
12189 {
12192 }
12202 }
12203 }
12205 /* Helper function for outputting the checksum of a tree T. When
12206 debugging with gdb, you can "define mynext" to be "next" followed
12207 by "call debug_fold_checksum (op0)", then just trace down till the
12208 outputs differ. */
12210 DEBUG_FUNCTION void
12212 {
12227 }
12229 #endif
12231 /* Fold a unary tree expression with code CODE of type TYPE with an
12232 operand OP0. LOC is the location of the resulting expression.
12233 Return a folded expression if successful. Otherwise, return a tree
12234 expression with code CODE of type TYPE with an operand OP0. */
12236 tree
12239 {
12240 tree tem;
12241 #ifdef ENABLE_FOLD_CHECKING
12250 #endif
12256 #ifdef ENABLE_FOLD_CHECKING
12263 #endif
12265 }
12267 /* Fold a binary tree expression with code CODE of type TYPE with
12268 operands OP0 and OP1. LOC is the location of the resulting
12269 expression. Return a folded expression if successful. Otherwise,
12270 return a tree expression with code CODE of type TYPE with operands
12271 OP0 and OP1. */
12273 tree
12276 MEM_STAT_DECL)
12277 {
12278 tree tem;
12279 #ifdef ENABLE_FOLD_CHECKING
12296 #endif
12302 #ifdef ENABLE_FOLD_CHECKING
12317 #endif
12319 }
12321 /* Fold a ternary tree expression with code CODE of type TYPE with
12322 operands OP0, OP1, and OP2. Return a folded expression if
12323 successful. Otherwise, return a tree expression with code CODE of
12324 type TYPE with operands OP0, OP1, and OP2. */
12326 tree
12329 {
12330 tree tem;
12331 #ifdef ENABLE_FOLD_CHECKING
12355 #endif
12362 #ifdef ENABLE_FOLD_CHECKING
12385 #endif
12387 }
12389 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12390 arguments in ARGARRAY, and a null static chain.
12391 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12392 of type TYPE from the given operands as constructed by build_call_array. */
12394 tree
12397 {
12398 tree tem;
12399 #ifdef ENABLE_FOLD_CHECKING
12418 #endif
12424 #ifdef ENABLE_FOLD_CHECKING
12440 #endif
12442 }
12444 /* Perform constant folding and related simplification of initializer
12445 expression EXPR. These behave identically to "fold_buildN" but ignore
12446 potential run-time traps and exceptions that fold must preserve. */
12448 #define START_FOLD_INIT \
12449 int saved_signaling_nans = flag_signaling_nans;\
12450 int saved_trapping_math = flag_trapping_math;\
12451 int saved_rounding_math = flag_rounding_math;\
12452 int saved_trapv = flag_trapv;\
12453 int saved_folding_initializer = folding_initializer;\
12454 flag_signaling_nans = 0;\
12455 flag_trapping_math = 0;\
12456 flag_rounding_math = 0;\
12457 flag_trapv = 0;\
12458 folding_initializer = 1;
12460 #define END_FOLD_INIT \
12461 flag_signaling_nans = saved_signaling_nans;\
12462 flag_trapping_math = saved_trapping_math;\
12463 flag_rounding_math = saved_rounding_math;\
12464 flag_trapv = saved_trapv;\
12465 folding_initializer = saved_folding_initializer;
12467 tree
12470 {
12471 tree result;
12472 START_FOLD_INIT;
12476 END_FOLD_INIT;
12478 }
12480 tree
12483 {
12484 tree result;
12485 START_FOLD_INIT;
12489 END_FOLD_INIT;
12491 }
12493 tree
12496 {
12497 tree result;
12498 START_FOLD_INIT;
12502 END_FOLD_INIT;
12504 }
12506 #undef START_FOLD_INIT
12507 #undef END_FOLD_INIT
12509 /* Determine if first argument is a multiple of second argument. Return 0 if
12510 it is not, or we cannot easily determined it to be.
12512 An example of the sort of thing we care about (at this point; this routine
12513 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12514 fold cases do now) is discovering that
12516 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12518 is a multiple of
12520 SAVE_EXPR (J * 8)
12522 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12524 This code also handles discovering that
12526 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12528 is a multiple of 8 so we don't have to worry about dealing with a
12529 possible remainder.
12531 Note that we *look* inside a SAVE_EXPR only to determine how it was
12532 calculated; it is not safe for fold to do much of anything else with the
12533 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12534 at run time. For example, the latter example above *cannot* be implemented
12535 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12536 evaluation time of the original SAVE_EXPR is not necessarily the same at
12537 the time the new expression is evaluated. The only optimization of this
12538 sort that would be valid is changing
12540 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12542 divided by 8 to
12544 SAVE_EXPR (I) * SAVE_EXPR (J)
12546 (where the same SAVE_EXPR (J) is used in the original and the
12547 transformed version). */
12549 int
12551 {
12562 {
12564 /* Bitwise and provides a power of two multiple. If the mask is
12565 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12568 /* FALLTHRU */
12575 /* It is impossible to prove if op0 - op1 is multiple of bottom
12576 precisely, so be conservative here checking if both op0 and op1
12577 are multiple of bottom. Note we check the second operand first
12578 since it's usually simpler. */
12583 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12584 as op0 - 3 if the expression has unsigned type. For example,
12585 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12595 {
12597 /* const_binop may not detect overflow correctly,
12598 so check for it explicitly here. */
12602 size_one_node,
12603 op1)))
12606 }
12610 /* Can't handle conversions from non-integral or wider integral type. */
12616 /* fall through */
12633 SIGNED);
12639 {
12642 /* Check for special cases to see if top is defined as multiple
12643 of bottom:
12645 top = (X & ~(bottom - 1) ; bottom is power of 2
12647 or
12649 Y = X % bottom
12650 top = X - Y. */
12669 }
12671 /* fall through */
12675 }
12676 }
12678 #define tree_expr_nonnegative_warnv_p(X, Y) \
12681 #define RECURSE(X) \
12682 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12684 /* Return true if CODE or TYPE is known to be non-negative. */
12686 static bool
12688 {
12691 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12692 have a signed:1 type (where the value is -1 and 0). */
12695 }
12697 /* Return true if (CODE OP0) is known to be non-negative. If the return
12698 value is based on the assumption that signed overflow is undefined,
12699 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12700 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12702 bool
12705 {
12710 {
12712 /* We can't return 1 if flag_wrapv is set because
12713 ABS_EXPR<INT_MIN> = INT_MIN. */
12717 {
12720 }
12728 CASE_CONVERT:
12729 {
12734 {
12738 {
12742 }
12743 }
12745 {
12751 }
12752 }
12757 }
12759 /* We don't know sign of `t', so be conservative and return false. */
12761 }
12763 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12764 value is based on the assumption that signed overflow is undefined,
12765 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12766 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12768 bool
12772 {
12777 {
12783 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12784 both unsigned and at least 2 bits shorter than the result. */
12788 {
12793 {
12797 }
12798 }
12803 {
12804 /* x * x is always non-negative for floating point x
12805 or without overflow. */
12808 {
12813 }
12814 }
12816 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12817 both unsigned and their total bits is shorter than the result. */
12821 {
12840 {
12850 }
12851 }
12878 }
12880 /* We don't know sign of `t', so be conservative and return false. */
12882 }
12884 /* Return true if T is known to be non-negative. If the return
12885 value is based on the assumption that signed overflow is undefined,
12886 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12887 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12889 bool
12891 {
12896 {
12910 /* Limit the depth of recursion to avoid quadratic behavior.
12911 This is expected to catch almost all occurrences in practice.
12912 If this code misses important cases that unbounded recursion
12913 would not, passes that need this information could be revised
12914 to provide it through dataflow propagation. */
12922 }
12923 }
12925 /* Return true if T is known to be non-negative. If the return
12926 value is based on the assumption that signed overflow is undefined,
12927 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12928 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12930 bool
12933 {
12935 {
12936 CASE_CFN_ACOS:
12937 CASE_CFN_ACOSH:
12938 CASE_CFN_CABS:
12939 CASE_CFN_COSH:
12940 CASE_CFN_ERFC:
12941 CASE_CFN_EXP:
12942 CASE_CFN_EXP10:
12943 CASE_CFN_EXP2:
12944 CASE_CFN_FABS:
12945 CASE_CFN_FDIM:
12946 CASE_CFN_HYPOT:
12947 CASE_CFN_POW10:
12948 CASE_CFN_FFS:
12949 CASE_CFN_PARITY:
12950 CASE_CFN_POPCOUNT:
12951 CASE_CFN_CLZ:
12952 CASE_CFN_CLRSB:
12955 /* Always true. */
12958 CASE_CFN_SQRT:
12959 /* sqrt(-0.0) is -0.0. */
12964 CASE_CFN_ASINH:
12965 CASE_CFN_ATAN:
12966 CASE_CFN_ATANH:
12967 CASE_CFN_CBRT:
12968 CASE_CFN_CEIL:
12969 CASE_CFN_ERF:
12970 CASE_CFN_EXPM1:
12971 CASE_CFN_FLOOR:
12972 CASE_CFN_FMOD:
12973 CASE_CFN_FREXP:
12974 CASE_CFN_ICEIL:
12975 CASE_CFN_IFLOOR:
12976 CASE_CFN_IRINT:
12977 CASE_CFN_IROUND:
12978 CASE_CFN_LCEIL:
12979 CASE_CFN_LDEXP:
12980 CASE_CFN_LFLOOR:
12981 CASE_CFN_LLCEIL:
12982 CASE_CFN_LLFLOOR:
12983 CASE_CFN_LLRINT:
12984 CASE_CFN_LLROUND:
12985 CASE_CFN_LRINT:
12986 CASE_CFN_LROUND:
12987 CASE_CFN_MODF:
12988 CASE_CFN_NEARBYINT:
12989 CASE_CFN_RINT:
12990 CASE_CFN_ROUND:
12991 CASE_CFN_SCALB:
12992 CASE_CFN_SCALBLN:
12993 CASE_CFN_SCALBN:
12994 CASE_CFN_SIGNBIT:
12995 CASE_CFN_SIGNIFICAND:
12996 CASE_CFN_SINH:
12997 CASE_CFN_TANH:
12998 CASE_CFN_TRUNC:
12999 /* True if the 1st argument is nonnegative. */
13002 CASE_CFN_FMAX:
13003 /* True if the 1st OR 2nd arguments are nonnegative. */
13006 CASE_CFN_FMIN:
13007 /* True if the 1st AND 2nd arguments are nonnegative. */
13010 CASE_CFN_COPYSIGN:
13011 /* True if the 2nd argument is nonnegative. */
13014 CASE_CFN_POWI:
13015 /* True if the 1st argument is nonnegative or the second
13016 argument is an even integer. */
13022 CASE_CFN_POW:
13023 /* True if the 1st argument is nonnegative or the second
13024 argument is an even integer valued real. */
13026 {
13027 REAL_VALUE_TYPE c;
13028 HOST_WIDE_INT n;
13033 {
13034 REAL_VALUE_TYPE cint;
13038 }
13039 }
13044 }
13046 }
13048 /* Return true if T is known to be non-negative. If the return
13049 value is based on the assumption that signed overflow is undefined,
13050 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13051 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13053 static bool
13055 {
13061 {
13063 {
13067 /* If the initializer is non-void, then it's a normal expression
13068 that will be assigned to the slot. */
13072 /* Otherwise, the initializer sets the slot in some way. One common
13073 way is an assignment statement at the end of the initializer. */
13075 {
13083 else
13085 }
13091 }
13094 {
13100 arg0,
13101 arg1,
13103 }
13116 }
13117 }
13119 #undef RECURSE
13120 #undef tree_expr_nonnegative_warnv_p
13122 /* Return true if T is known to be non-negative. If the return
13123 value is based on the assumption that signed overflow is undefined,
13124 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13125 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13127 bool
13129 {
13136 {
13158 }
13161 {
13187 }
13188 }
13190 /* Return true if `t' is known to be non-negative. Handle warnings
13191 about undefined signed overflow. */
13193 bool
13195 {
13202 "determining that expression is always "
13204 WARN_STRICT_OVERFLOW_MISC);
13206 }
13209 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13210 For floating point we further ensure that T is not denormal.
13211 Similar logic is present in nonzero_address in rtlanal.h.
13213 If the return value is based on the assumption that signed overflow
13214 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13215 change *STRICT_OVERFLOW_P. */
13217 bool
13220 {
13222 {
13225 strict_overflow_p);
13228 {
13234 strict_overflow_p));
13235 }
13240 strict_overflow_p);
13244 }
13247 }
13249 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13250 For floating point we further ensure that T is not denormal.
13251 Similar logic is present in nonzero_address in rtlanal.h.
13253 If the return value is based on the assumption that signed overflow
13254 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13255 change *STRICT_OVERFLOW_P. */
13257 bool
13259 tree type,
13260 tree op0,
13262 {
13265 {
13269 {
13270 /* With the presence of negative values it is hard
13271 to say something. */
13278 /* One of operands must be positive and the other non-negative. */
13279 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13280 overflows, on a twos-complement machine the sum of two
13281 nonnegative numbers can never be zero. */
13283 strict_overflow_p)
13285 strict_overflow_p));
13286 }
13291 {
13293 strict_overflow_p)
13295 strict_overflow_p))
13296 {
13299 }
13300 }
13309 {
13312 }
13319 {
13323 /* When both operands are nonzero, then MAX must be too. */
13325 strict_overflow_p))
13328 /* MAX where operand 0 is positive is positive. */
13330 strict_overflow_p);
13331 }
13332 /* MAX where operand 1 is positive is positive. */
13337 {
13341 }
13346 strict_overflow_p)
13348 strict_overflow_p));
13352 }
13355 }
13357 /* Return true when T is an address and is known to be nonzero.
13358 For floating point we further ensure that T is not denormal.
13359 Similar logic is present in nonzero_address in rtlanal.h.
13361 If the return value is based on the assumption that signed overflow
13362 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13363 change *STRICT_OVERFLOW_P. */
13365 bool
13367 {
13370 {
13375 {
13387 /* For objects in symbol table check if we know they are non-zero.
13388 Don't do anything for variables and functions before symtab is built;
13389 it is quite possible that they will be declared weak later. */
13394 /* Constants are never weak. */
13399 }
13407 {
13411 }
13421 }
13423 }
13425 #define integer_valued_real_p(X) \
13428 #define RECURSE(X) \
13429 ((integer_valued_real_p) (X, depth + 1))
13431 /* Return true if the floating point result of (CODE OP0) has an
13432 integer value. We also allow +Inf, -Inf and NaN to be considered
13433 integer values. Return false for signaling NaN.
13435 DEPTH is the current nesting depth of the query. */
13437 bool
13439 {
13441 {
13448 CASE_CONVERT:
13449 {
13456 }
13460 }
13462 }
13464 /* Return true if the floating point result of (CODE OP0 OP1) has an
13465 integer value. We also allow +Inf, -Inf and NaN to be considered
13466 integer values. Return false for signaling NaN.
13468 DEPTH is the current nesting depth of the query. */
13470 bool
13472 {
13474 {
13484 }
13486 }
13488 /* Return true if the floating point result of calling FNDECL with arguments
13489 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13490 considered integer values. Return false for signaling NaN. If FNDECL
13491 takes fewer than 2 arguments, the remaining ARGn are null.
13493 DEPTH is the current nesting depth of the query. */
13495 bool
13497 {
13499 {
13500 CASE_CFN_CEIL:
13501 CASE_CFN_FLOOR:
13502 CASE_CFN_NEARBYINT:
13503 CASE_CFN_RINT:
13504 CASE_CFN_ROUND:
13505 CASE_CFN_TRUNC:
13508 CASE_CFN_FMIN:
13509 CASE_CFN_FMAX:
13514 }
13516 }
13518 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13519 has an integer value. We also allow +Inf, -Inf and NaN to be
13520 considered integer values. Return false for signaling NaN.
13522 DEPTH is the current nesting depth of the query. */
13524 bool
13526 {
13528 {
13536 /* Limit the depth of recursion to avoid quadratic behavior.
13537 This is expected to catch almost all occurrences in practice.
13538 If this code misses important cases that unbounded recursion
13539 would not, passes that need this information could be revised
13540 to provide it through dataflow propagation. */
13544 depth));
13548 }
13550 }
13552 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13553 has an integer value. We also allow +Inf, -Inf and NaN to be
13554 considered integer values. Return false for signaling NaN.
13556 DEPTH is the current nesting depth of the query. */
13558 static bool
13560 {
13562 {
13573 }
13575 }
13577 #undef RECURSE
13578 #undef integer_valued_real_p
13580 /* Return true if the floating point expression T has an integer value.
13581 We also allow +Inf, -Inf and NaN to be considered integer values.
13582 Return false for signaling NaN.
13584 DEPTH is the current nesting depth of the query. */
13586 bool
13588 {
13594 {
13610 }
13613 {
13619 {
13628 }
13632 }
13633 }
13635 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13636 attempt to fold the expression to a constant without modifying TYPE,
13637 OP0 or OP1.
13639 If the expression could be simplified to a constant, then return
13640 the constant. If the expression would not be simplified to a
13641 constant, then return NULL_TREE. */
13643 tree
13645 {
13648 }
13650 /* Given the components of a unary expression CODE, TYPE and OP0,
13651 attempt to fold the expression to a constant without modifying
13652 TYPE or OP0.
13654 If the expression could be simplified to a constant, then return
13655 the constant. If the expression would not be simplified to a
13656 constant, then return NULL_TREE. */
13658 tree
13660 {
13663 }
13665 /* If EXP represents referencing an element in a constant string
13666 (either via pointer arithmetic or array indexing), return the
13667 tree representing the value accessed, otherwise return NULL. */
13669 tree
13671 {
13675 {
13677 tree index;
13678 tree string;
13683 else
13684 {
13688 /* Optimize the special-case of a zero lower bound.
13690 We convert the low_bound to sizetype to avoid some problems
13691 with constant folding. (E.g. suppose the lower bound is 1,
13692 and its mode is QI. Without the conversion,l (ARRAY
13693 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13694 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13700 }
13713 }
13715 }
13717 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13718 an integer constant, real, or fixed-point constant.
13720 TYPE is the type of the result. */
13722 static tree
13724 {
13728 {
13730 {
13737 }
13744 {
13745 FIXED_VALUE_TYPE f;
13750 /* Propagate overflow flags. */
13754 }
13758 }
13761 }
13763 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13764 an integer constant or real constant.
13766 TYPE is the type of the result. */
13768 tree
13770 {
13774 {
13776 {
13777 /* If the value is unsigned or non-negative, then the absolute value
13778 is the same as the ordinary value. */
13782 /* If the value is negative, then the absolute value is
13783 its negation. */
13784 else
13785 {
13790 }
13791 }
13797 else
13803 }
13806 }
13808 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13809 constant. TYPE is the type of the result. */
13811 static tree
13813 {
13817 }
13819 /* Given CODE, a relational operator, the target type, TYPE and two
13820 constant operands OP0 and OP1, return the result of the
13821 relational operation. If the result is not a compile time
13822 constant, then return NULL_TREE. */
13824 static tree
13826 {
13829 /* From here on, the only cases we handle are when the result is
13830 known to be a constant. */
13833 {
13837 /* Handle the cases where either operand is a NaN. */
13839 {
13841 {
13869 }
13872 }
13875 }
13878 {
13882 }
13884 /* Handle equality/inequality of complex constants. */
13886 {
13897 else
13899 }
13902 {
13904 {
13905 /* Have vector comparison with scalar boolean result. */
13909 {
13917 }
13919 }
13926 {
13938 }
13941 }
13943 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13945 To compute GT, swap the arguments and do LT.
13946 To compute GE, do LT and invert the result.
13947 To compute LE, swap the arguments, do LT and invert the result.
13948 To compute NE, do EQ and invert the result.
13950 Therefore, the code below must handle only EQ and LT. */
13953 {
13956 }
13958 /* Note that it is safe to invert for real values here because we
13959 have already handled the one case that it matters. */
13963 {
13966 }
13968 /* Compute a result for LT or EQ if args permit;
13969 Otherwise return T. */
13971 {
13974 else
13976 }
13977 else
13983 }
13985 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13986 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13987 itself. */
13989 tree
13991 {
13992 /* If the expression does not have side effects then we don't have to wrap
13993 it with a cleanup point expression. */
13997 /* If the expression is a return, check to see if the expression inside the
13998 return has no side effects or the right hand side of the modify expression
13999 inside the return. If either don't have side effects set we don't need to
14000 wrap the expression in a cleanup point expression. Note we don't check the
14001 left hand side of the modify because it should always be a return decl. */
14003 {
14010 }
14013 }
14015 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14016 of an indirection through OP0, or NULL_TREE if no simplification is
14017 possible. */
14019 tree
14021 {
14023 tree subtype;
14032 {
14035 /* *&CONST_DECL -> to the value of the const decl. */
14038 /* *&p => p; make sure to handle *&"str"[cst] here. */
14040 {
14044 else
14046 }
14047 /* *(foo *)&fooarray => fooarray[0] */
14050 && (!in_gimple_form
14052 {
14062 }
14063 /* *(foo *)&complexfoo => __real__ complexfoo */
14067 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14070 {
14074 }
14075 }
14079 {
14085 {
14086 tree op00type;
14090 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14093 {
14095 unsigned HOST_WIDE_INT max_offset
14100 {
14107 }
14108 }
14109 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14112 {
14116 }
14117 /* ((foo *)&fooarray)[1] => fooarray[1] */
14120 {
14130 }
14131 }
14132 }
14134 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14137 && (!in_gimple_form
14139 {
14140 tree type_domain;
14150 NULL_TREE);
14151 }
14154 }
14156 /* Builds an expression for an indirection through T, simplifying some
14157 cases. */
14159 tree
14161 {
14169 }
14171 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14173 tree
14175 {
14180 else
14182 }
14184 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14185 whose result is ignored. The type of the returned tree need not be
14186 the same as the original expression. */
14188 tree
14190 {
14196 {
14207 else
14213 {
14229 }
14234 }
14235 }
14237 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14239 tree
14241 {
14247 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14248 have to do anything. Only do this when we are not given a const,
14249 because in that case, this check is more expensive than just
14250 doing it. */
14252 {
14257 }
14259 /* If divisor is a power of two, simplify this to bit manipulation. */
14261 {
14263 {
14277 }
14278 else
14279 {
14280 tree t;
14286 }
14287 }
14288 else
14289 {
14294 }
14297 }
14299 /* Likewise, but round down. */
14301 tree
14303 {
14310 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14311 have to do anything. Only do this when we are not given a const,
14312 because in that case, this check is more expensive than just
14313 doing it. */
14315 {
14320 }
14322 /* If divisor is a power of two, simplify this to bit manipulation. */
14324 {
14325 tree t;
14329 }
14330 else
14331 {
14336 }
14339 }
14341 /* Returns the pointer to the base of the object addressed by EXP and
14342 extracts the information about the offset of the access, storing it
14343 to PBITPOS and POFFSET. */
14345 static tree
14348 {
14349 tree core;
14350 machine_mode mode;
14352 HOST_WIDE_INT bitsize;
14356 {
14361 }
14363 {
14369 {
14374 {
14377 }
14378 }
14379 }
14380 else
14381 {
14385 }
14388 }
14390 /* Returns true if addresses of E1 and E2 differ by a constant, false
14391 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14393 bool
14395 {
14409 {
14419 }
14421 {
14422 /* If only one of the offsets is non-constant, the difference cannot
14423 be a constant. */
14425 }
14426 else
14431 }
14433 /* Return OFF converted to a pointer offset type suitable as offset for
14434 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14435 tree
14437 {
14439 }
14441 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14442 tree
14444 {
14447 }
14449 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14450 tree
14452 {
14455 }
14457 /* Return a char pointer for a C string if it is a string constant
14458 or sum of string constant and integer constant. We only support
14459 string constants properly terminated with '\0' character.
14460 If STRLEN is a valid pointer, length (including terminating character)
14461 of returned string is stored to the argument. */
14465 {
14466 tree offset_node;
14477 {
14480 else
14482 }
14487 /* Support only properly null-terminated strings. */
14496 }
14498 #if CHECKING_P
14502 /* Helper functions for writing tests of folding trees. */
14504 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14506 static void
14508 tree constant)
14509 {
14511 }
14513 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14514 wrapping WRAPPED_EXPR. */
14516 static void
14518 tree wrapped_expr)
14519 {
14524 }
14526 /* Verify that various arithmetic binary operations are folded
14527 correctly. */
14529 static void
14531 {
14537 /* Addition. */
14538 /* 1 <-- (0 + 1) */
14540 one);
14542 one);
14544 /* (nonlvalue)x <-- (x + 0) */
14546 x);
14548 /* Subtraction. */
14549 /* 0 <-- (x - x) */
14551 zero);
14553 x);
14555 /* Multiplication. */
14556 /* 0 <-- (x * 0) */
14558 zero);
14560 /* (nonlvalue)x <-- (x * 1) */
14562 x);
14563 }
14565 /* Verify that various binary operations on vectors are folded
14566 correctly. */
14568 static void
14570 {
14576 /* Verify equality tests that return a scalar boolean result. */
14582 }
14584 /* Run all of the selftests within this file. */
14586 void
14588 {
14591 }