| blob | e34bc81eae8f1458730e9c68d465d9180dbc9285 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2016 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
80 #ifndef LOAD_EXTEND_OP
81 #define LOAD_EXTEND_OP(M) UNKNOWN
82 #endif
84 /* Nonzero if we are folding constants inside an initializer; zero
85 otherwise. */
88 /* The following constants represent a bit based encoding of GCC's
89 comparison operators. This encoding simplifies transformations
90 on relational comparison operators, such as AND and OR. */
108 };
125 HOST_WIDE_INT *,
154 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
155 Otherwise, return LOC. */
157 static location_t
159 {
162 }
164 /* Similar to protected_set_expr_location, but never modify x in place,
165 if location can and needs to be set, unshare it. */
169 {
175 {
178 }
180 }
181 \f
182 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
183 division and returns the quotient. Otherwise returns
184 NULL_TREE. */
186 tree
188 {
189 widest_int quo;
196 }
197 \f
198 /* This is nonzero if we should defer warnings about undefined
199 overflow. This facility exists because these warnings are a
200 special case. The code to estimate loop iterations does not want
201 to issue any warnings, since it works with expressions which do not
202 occur in user code. Various bits of cleanup code call fold(), but
203 only use the result if it has certain characteristics (e.g., is a
204 constant); that code only wants to issue a warning if the result is
205 used. */
209 /* If a warning about undefined overflow is deferred, this is the
210 warning. Note that this may cause us to turn two warnings into
211 one, but that is fine since it is sufficient to only give one
212 warning per expression. */
216 /* If a warning about undefined overflow is deferred, this is the
217 level at which the warning should be emitted. */
221 /* Start deferring overflow warnings. We could use a stack here to
222 permit nested calls, but at present it is not necessary. */
224 void
226 {
228 }
230 /* Stop deferring overflow warnings. If there is a pending warning,
231 and ISSUE is true, then issue the warning if appropriate. STMT is
232 the statement with which the warning should be associated (used for
233 location information); STMT may be NULL. CODE is the level of the
234 warning--a warn_strict_overflow_code value. This function will use
235 the smaller of CODE and the deferred code when deciding whether to
236 issue the warning. CODE may be zero to mean to always use the
237 deferred code. */
239 void
241 {
243 location_t locus;
248 {
254 }
265 /* Use the smallest code level when deciding to issue the
266 warning. */
275 else
278 }
280 /* Stop deferring overflow warnings, ignoring any deferred
281 warnings. */
283 void
285 {
287 }
289 /* Whether we are deferring overflow warnings. */
291 bool
293 {
295 }
297 /* This is called when we fold something based on the fact that signed
298 overflow is undefined. */
300 static void
302 {
304 {
307 {
310 }
311 }
314 }
315 \f
316 /* Return true if the built-in mathematical function specified by CODE
317 is odd, i.e. -f(x) == f(-x). */
319 bool
321 {
323 {
324 CASE_CFN_ASIN:
325 CASE_CFN_ASINH:
326 CASE_CFN_ATAN:
327 CASE_CFN_ATANH:
328 CASE_CFN_CASIN:
329 CASE_CFN_CASINH:
330 CASE_CFN_CATAN:
331 CASE_CFN_CATANH:
332 CASE_CFN_CBRT:
333 CASE_CFN_CPROJ:
334 CASE_CFN_CSIN:
335 CASE_CFN_CSINH:
336 CASE_CFN_CTAN:
337 CASE_CFN_CTANH:
338 CASE_CFN_ERF:
339 CASE_CFN_LLROUND:
340 CASE_CFN_LROUND:
341 CASE_CFN_ROUND:
342 CASE_CFN_SIN:
343 CASE_CFN_SINH:
344 CASE_CFN_TAN:
345 CASE_CFN_TANH:
346 CASE_CFN_TRUNC:
349 CASE_CFN_LLRINT:
350 CASE_CFN_LRINT:
351 CASE_CFN_NEARBYINT:
352 CASE_CFN_RINT:
357 }
359 }
361 /* Check whether we may negate an integer constant T without causing
362 overflow. */
364 bool
366 {
367 tree type;
376 }
378 /* Determine whether an expression T can be cheaply negated using
379 the function negate_expr without introducing undefined overflow. */
381 static bool
383 {
384 tree type;
393 {
398 /* Check that -CST will not overflow type. */
411 /* We want to canonicalize to positive real constants. Pretend
412 that only negative ones can be easily negated. */
420 {
431 }
446 /* -(A + B) -> (-B) - A. */
451 /* -(A + B) -> (-A) - B. */
455 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
466 /* INT_MIN/n * n doesn't overflow while negating one operand it does
467 if n is a power of two. */
476 /* Fall through. */
491 /* In general we can't negate B in A / B, because if A is INT_MIN and
492 B is 1, we may turn this into INT_MIN / -1 which is undefined
493 and actually traps on some architectures. */
502 /* Negate -((double)float) as (double)(-float). */
504 {
508 }
512 /* Negate -f(x) as f(-x). */
518 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
520 {
524 }
529 }
531 }
533 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
534 simplification is possible.
535 If negate_expr_p would return true for T, NULL_TREE will never be
536 returned. */
538 static tree
540 {
542 tree tem;
545 {
546 /* Convert - (~A) to A + 1. */
572 {
577 }
581 {
586 {
590 }
593 }
616 {
617 /* -(A + B) -> (-B) - A. */
621 {
625 }
627 /* -(A + B) -> (-A) - B. */
629 {
633 }
634 }
638 /* - (A - B) -> B - A */
650 /* Fall through. */
654 {
663 }
675 /* In general we can't negate B in A / B, because if A is INT_MIN and
676 B is 1, we may turn this into INT_MIN / -1 which is undefined
677 and actually traps on some architectures. */
689 /* Convert -((double)float) into (double)(-float). */
691 {
695 }
699 /* Negate -f(x) as f(-x). */
702 {
708 }
712 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
714 {
717 {
724 }
725 }
730 }
733 }
735 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
736 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
737 return NULL_TREE. */
739 static tree
741 {
743 location_t loc;
756 }
757 \f
758 /* Split a tree IN into a constant, literal and variable parts that could be
759 combined with CODE to make IN. "constant" means an expression with
760 TREE_CONSTANT but that isn't an actual constant. CODE must be a
761 commutative arithmetic operation. Store the constant part into *CONP,
762 the literal in *LITP and return the variable part. If a part isn't
763 present, set it to null. If the tree does not decompose in this way,
764 return the entire tree as the variable part and the other parts as null.
766 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
767 case, we negate an operand that was subtracted. Except if it is a
768 literal for which we use *MINUS_LITP instead.
770 If NEGATE_P is true, we are negating all of IN, again except a literal
771 for which we use *MINUS_LITP instead. If a variable part is of pointer
772 type, it is negated after converting to TYPE. This prevents us from
773 generating illegal MINUS pointer expression. LOC is the location of
774 the converted variable part.
776 If IN is itself a literal or constant, return it as appropriate.
778 Note that we do not guarantee that any of the three values will be the
779 same type as IN, but they will have the same signedness and mode. */
781 static tree
784 {
791 /* Strip any conversions that don't change the machine mode or signedness. */
800 /* We can associate addition and subtraction together (even
801 though the C standard doesn't say so) for integers because
802 the value is not affected. For reals, the value might be
803 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. */
840 {
841 /* Convert to TYPE before negating a pointer type expr. */
845 }
846 }
849 {
850 /* -X - 1 is folded to ~X, undo that here. */
853 }
856 else
860 {
866 /* Convert to TYPE before negating a pointer type expr. */
870 }
873 }
875 /* Re-associate trees split by the above function. T1 and T2 are
876 either expressions to associate or null. Return the new
877 expression, if any. LOC is the location of the new expression. If
878 we build an operation, do it in TYPE and with CODE. */
880 static tree
882 {
888 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
889 try to fold this since we will have infinite recursion. But do
890 deal with any NEGATE_EXPRs. */
893 {
895 {
908 }
910 {
913 }
917 }
921 }
922 \f
923 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
924 for use in int_const_binop, size_binop and size_diffop. */
926 static bool
928 {
935 {
944 }
949 }
952 /* Combine two integer constants ARG1 and ARG2 under operation CODE
953 to produce a new constant. Return NULL_TREE if we don't know how
954 to evaluate CODE at compile-time. */
956 static tree
959 {
960 wide_int res;
961 tree t;
970 {
986 {
990 else
992 }
995 /* It's unclear from the C standard whether shifts can overflow.
996 The following code ignores overflow; perhaps a C standard
997 interpretation ruling is needed. */
999 else
1006 {
1010 else
1012 }
1016 else
1095 }
1103 }
1105 tree
1107 {
1109 }
1111 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1112 constant. We assume ARG1 and ARG2 have the same data type, or at least
1113 are the same kind of constant and the same machine mode. Return zero if
1114 combining the constants is not allowed in the current operating mode. */
1116 static tree
1118 {
1119 /* Sanity check for the recursive cases. */
1127 {
1133 }
1136 {
1137 machine_mode mode;
1138 REAL_VALUE_TYPE d1;
1139 REAL_VALUE_TYPE d2;
1140 REAL_VALUE_TYPE value;
1141 REAL_VALUE_TYPE result;
1145 /* The following codes are handled by real_arithmetic. */
1147 {
1158 }
1166 /* Don't perform operation if we honor signaling NaNs and
1167 either operand is a signaling NaN. */
1173 /* Don't perform operation if it would raise a division
1174 by zero exception. */
1180 /* If either operand is a NaN, just return it. Otherwise, set up
1181 for floating-point trap; we return an overflow. */
1183 {
1184 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1185 is off. */
1189 }
1191 {
1192 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1193 is off. */
1197 }
1202 /* Don't constant fold this floating point operation if
1203 the result has overflowed and flag_trapping_math. */
1211 /* Don't constant fold this floating point operation if the
1212 result may dependent upon the run-time rounding mode and
1213 flag_rounding_math is set, or if GCC's software emulation
1214 is unable to accurately represent the result. */
1224 }
1227 {
1228 FIXED_VALUE_TYPE f1;
1229 FIXED_VALUE_TYPE f2;
1230 FIXED_VALUE_TYPE result;
1235 /* The following codes are handled by fixed_arithmetic. */
1237 {
1249 {
1256 }
1261 }
1268 /* Propagate overflow flags. */
1272 }
1275 {
1284 {
1295 mpc_mul);
1309 mpc_div);
1310 /* Fallthru ... */
1316 {
1317 /* Keep this algorithm in sync with
1318 tree-complex.c:expand_complex_div_straight().
1320 Expand complex division to scalars, straightforward algorithm.
1321 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1322 t = br*br + bi*bi
1323 */
1324 tree magsquared
1328 tree t1
1332 tree t2
1339 }
1340 else
1341 {
1342 /* Keep this algorithm in sync with
1343 tree-complex.c:expand_complex_div_wide().
1345 Expand complex division to scalars, modified algorithm to minimize
1346 overflow with wide input ranges. */
1352 {
1353 /* In the TRUE branch, we compute
1354 ratio = br/bi;
1355 div = (br * ratio) + bi;
1356 tr = (ar * ratio) + ai;
1357 ti = (ai * ratio) - ar;
1358 tr = tr / div;
1359 ti = ti / div; */
1370 }
1371 else
1372 {
1373 /* In the FALSE branch, we compute
1374 ratio = d/c;
1375 divisor = (d * ratio) + c;
1376 tr = (b * ratio) + a;
1377 ti = b - (a * ratio);
1378 tr = tr / div;
1379 ti = ti / div; */
1391 }
1392 }
1397 }
1401 }
1405 {
1411 {
1417 /* It is possible that const_binop cannot handle the given
1418 code and return NULL_TREE */
1421 }
1424 }
1426 /* Shifts allow a scalar offset for a vector. */
1429 {
1435 {
1440 /* It is possible that const_binop cannot handle the given
1441 code and return NULL_TREE. */
1444 }
1447 }
1449 }
1451 /* Overload that adds a TYPE parameter to be able to dispatch
1452 to fold_relational_const. */
1454 tree
1456 {
1460 /* ??? Until we make the const_binop worker take the type of the
1461 result as argument put those cases that need it here. */
1463 {
1474 {
1490 {
1496 }
1499 }
1505 {
1530 {
1543 }
1546 }
1549 }
1554 /* Make sure type and arg0 have the same saturating flag. */
1559 }
1561 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1562 Return zero if computing the constants is not possible. */
1564 tree
1566 {
1567 /* Don't perform the operation, other than NEGATE and ABS, if
1568 flag_signaling_nans is on and the operand is a signaling NaN. */
1577 {
1578 CASE_CONVERT:
1585 /* If the source address is 0, and the source address space
1586 cannot have a valid object at 0, fold to dest type null. */
1597 {
1598 /* Can't call fold_negate_const directly here as that doesn't
1599 handle all cases and we might not be able to negate some
1600 constants. */
1605 }
1614 {
1618 }
1624 /* Perform BIT_NOT_EXPR on each element individually. */
1626 {
1628 tree elem;
1633 {
1639 }
1642 }
1664 {
1683 else
1687 {
1691 }
1694 }
1699 {
1713 {
1718 }
1721 {
1725 }
1728 }
1732 }
1735 }
1737 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1738 indicates which particular sizetype to create. */
1740 tree
1742 {
1744 }
1745 \f
1746 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1747 is a tree code. The type of the result is taken from the operands.
1748 Both must be equivalent integer types, ala int_binop_types_match_p.
1749 If the operands are constant, so is the result. */
1751 tree
1753 {
1762 /* Handle the special case of two integer constants faster. */
1764 {
1765 /* And some specific cases even faster than that. */
1767 {
1772 }
1774 {
1777 }
1779 {
1782 }
1784 /* Handle general case of two integer constants. For sizetype
1785 constant calculations we always want to know about overflow,
1786 even in the unsigned case. */
1788 }
1791 }
1793 /* Given two values, either both of sizetype or both of bitsizetype,
1794 compute the difference between the two values. Return the value
1795 in signed type corresponding to the type of the operands. */
1797 tree
1799 {
1801 tree ctype;
1806 /* If the type is already signed, just do the simple thing. */
1814 else
1817 /* If either operand is not a constant, do the conversions to the signed
1818 type and subtract. The hardware will do the right thing with any
1819 overflow in the subtraction. */
1825 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1826 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1827 overflow) and negate (which can't either). Special-case a result
1828 of zero while we're here. */
1834 else
1838 MINUS_EXPR,
1840 }
1841 \f
1842 /* A subroutine of fold_convert_const handling conversions of an
1843 INTEGER_CST to another integer type. */
1845 static tree
1847 {
1848 /* Given an integer constant, make new constant with new type,
1849 appropriately sign-extended or truncated. Use widest_int
1850 so that any extension is done according ARG1's type. */
1854 }
1856 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1857 to an integer type. */
1859 static tree
1861 {
1863 tree t;
1865 /* The following code implements the floating point to integer
1866 conversion rules required by the Java Language Specification,
1867 that IEEE NaNs are mapped to zero and values that overflow
1868 the target precision saturate, i.e. values greater than
1869 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1870 are mapped to INT_MIN. These semantics are allowed by the
1871 C and C++ standards that simply state that the behavior of
1872 FP-to-integer conversion is unspecified upon overflow. */
1874 wide_int val;
1875 REAL_VALUE_TYPE r;
1879 {
1886 }
1888 /* If R is NaN, return zero and show we have an overflow. */
1890 {
1893 }
1895 /* See if R is less than the lower bound or greater than the
1896 upper bound. */
1899 {
1903 {
1906 }
1907 }
1910 {
1913 {
1916 {
1919 }
1920 }
1921 }
1928 }
1930 /* A subroutine of fold_convert_const handling conversions of a
1931 FIXED_CST to an integer type. */
1933 static tree
1935 {
1936 tree t;
1940 /* Right shift FIXED_CST to temp by fbit. */
1944 {
1946 HOST_BITS_PER_DOUBLE_INT,
1949 /* Left shift temp to temp_trunc by fbit. */
1951 HOST_BITS_PER_DOUBLE_INT,
1953 }
1954 else
1955 {
1958 }
1960 /* If FIXED_CST is negative, we need to round the value toward 0.
1961 By checking if the fractional bits are not zero to add 1 to temp. */
1967 /* Given a fixed-point constant, make new constant with new type,
1968 appropriately sign-extended or truncated. */
1976 }
1978 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1979 to another floating point type. */
1981 static tree
1983 {
1984 REAL_VALUE_TYPE value;
1985 tree t;
1987 /* Don't perform the operation if flag_signaling_nans is on
1988 and the operand is a signaling NaN. */
1996 /* If converting an infinity or NAN to a representation that doesn't
1997 have one, set the overflow bit so that we can produce some kind of
1998 error message at the appropriate point if necessary. It's not the
1999 most user-friendly message, but it's better than nothing. */
2006 /* Regular overflow, conversion produced an infinity in a mode that
2007 can't represent them. */
2012 else
2015 }
2017 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2018 to a floating point type. */
2020 static tree
2022 {
2023 REAL_VALUE_TYPE value;
2024 tree t;
2031 }
2033 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2034 to another fixed-point type. */
2036 static tree
2038 {
2039 FIXED_VALUE_TYPE value;
2040 tree t;
2047 /* Propagate overflow flags. */
2051 }
2053 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2054 to a fixed-point type. */
2056 static tree
2058 {
2059 FIXED_VALUE_TYPE value;
2060 tree t;
2062 double_int di;
2069 else
2077 /* Propagate overflow flags. */
2081 }
2083 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2084 to a fixed-point type. */
2086 static tree
2088 {
2089 FIXED_VALUE_TYPE value;
2090 tree t;
2098 /* Propagate overflow flags. */
2102 }
2104 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2105 type TYPE. If no simplification can be done return NULL_TREE. */
2107 static tree
2109 {
2115 {
2122 }
2124 {
2131 }
2133 {
2140 }
2142 {
2145 {
2150 {
2156 }
2158 }
2159 }
2161 }
2163 /* Construct a vector of zero elements of vector type TYPE. */
2165 static tree
2167 {
2168 tree t;
2172 }
2174 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2176 bool
2178 {
2193 {
2209 }
2210 }
2212 /* Convert expression ARG to type TYPE. Used by the middle-end for
2213 simple conversions in preference to calling the front-end's convert. */
2215 tree
2217 {
2219 tree tem;
2230 {
2233 /* Handle conversions between pointers to different address spaces. */
2238 /* fall through */
2243 {
2247 }
2261 {
2265 }
2267 {
2271 }
2273 {
2277 }
2280 {
2298 }
2303 {
2307 }
2310 {
2324 }
2328 {
2337 integer_zero_node));
2339 {
2343 {
2349 }
2357 }
2361 }
2379 }
2380 fold_convert_exit:
2383 }
2384 \f
2385 /* Return false if expr can be assumed not to be an lvalue, true
2386 otherwise. */
2388 static bool
2390 {
2391 /* We only need to wrap lvalue tree codes. */
2393 {
2424 /* Assume the worst for front-end tree codes. */
2428 }
2431 }
2433 /* Return an expr equal to X but certainly not valid as an lvalue. */
2435 tree
2437 {
2438 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2439 us. */
2446 }
2448 /* When pedantic, return an expr equal to X but certainly not valid as a
2449 pedantic lvalue. Otherwise, return X. */
2451 static tree
2453 {
2455 }
2456 \f
2457 /* Given a tree comparison code, return the code that is the logical inverse.
2458 It is generally not safe to do this for floating-point comparisons, except
2459 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2460 ERROR_MARK in this case. */
2462 enum tree_code
2464 {
2470 {
2501 }
2502 }
2504 /* Similar, but return the comparison that results if the operands are
2505 swapped. This is safe for floating-point. */
2507 enum tree_code
2509 {
2511 {
2537 }
2538 }
2541 /* Convert a comparison tree code from an enum tree_code representation
2542 into a compcode bit-based encoding. This function is the inverse of
2543 compcode_to_comparison. */
2545 static enum comparison_code
2547 {
2549 {
2580 }
2581 }
2583 /* Convert a compcode bit-based encoding of a comparison operator back
2584 to GCC's enum tree_code representation. This function is the
2585 inverse of comparison_to_compcode. */
2587 static enum tree_code
2589 {
2591 {
2622 }
2623 }
2625 /* Return a tree for the comparison which is the combination of
2626 doing the AND or OR (depending on CODE) of the two operations LCODE
2627 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2628 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2629 if this makes the transformation invalid. */
2631 tree
2636 {
2643 {
2654 }
2657 {
2658 /* Eliminate unordered comparisons, as well as LTGT and ORD
2659 which are not used unless the mode has NaNs. */
2665 }
2667 {
2668 /* Check that the original operation and the optimized ones will trap
2669 under the same condition. */
2680 /* In a short-circuited boolean expression the LHS might be
2681 such that the RHS, if evaluated, will never trap. For
2682 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2683 if neither x nor y is NaN. (This is a mixed blessing: for
2684 example, the expression above will never trap, hence
2685 optimizing it to x < y would be invalid). */
2690 /* If the comparison was short-circuited, and only the RHS
2691 trapped, we may now generate a spurious trap. */
2696 /* If we changed the conditions that cause a trap, we lose. */
2699 }
2705 else
2706 {
2711 }
2712 }
2713 \f
2714 /* Return nonzero if two operands (typically of the same tree node)
2715 are necessarily equal. FLAGS modifies behavior as follows:
2717 If OEP_ONLY_CONST is set, only return nonzero for constants.
2718 This function tests whether the operands are indistinguishable;
2719 it does not test whether they are equal using C's == operation.
2720 The distinction is important for IEEE floating point, because
2721 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2722 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2724 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2725 even though it may hold multiple values during a function.
2726 This is because a GCC tree node guarantees that nothing else is
2727 executed between the evaluation of its "operands" (which may often
2728 be evaluated in arbitrary order). Hence if the operands themselves
2729 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2730 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2731 unset means assuming isochronic (or instantaneous) tree equivalence.
2732 Unless comparing arbitrary expression trees, such as from different
2733 statements, this flag can usually be left unset.
2735 If OEP_PURE_SAME is set, then pure functions with identical arguments
2736 are considered the same. It is used when the caller has other ways
2737 to ensure that global memory is unchanged in between.
2739 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2740 not values of expressions.
2742 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2743 any operand with side effect. This is unnecesarily conservative in the
2744 case we know that arg0 and arg1 are in disjoint code paths (such as in
2745 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2746 addresses with TREE_CONSTANT flag set so we know that &var == &var
2747 even if var is volatile. */
2749 int
2751 {
2752 /* If either is ERROR_MARK, they aren't equal. */
2758 /* Similar, if either does not have a type (like a released SSA name),
2759 they aren't equal. */
2763 /* We cannot consider pointers to different address space equal. */
2770 /* Check equality of integer constants before bailing out due to
2771 precision differences. */
2773 {
2774 /* Address of INTEGER_CST is not defined; check that we did not forget
2775 to drop the OEP_ADDRESS_OF flags. */
2778 }
2781 {
2782 /* If both types don't have the same signedness, then we can't consider
2783 them equal. We must check this before the STRIP_NOPS calls
2784 because they may change the signedness of the arguments. As pointers
2785 strictly don't have a signedness, require either two pointers or
2786 two non-pointers as well. */
2792 /* If both types don't have the same precision, then it is not safe
2793 to strip NOPs. */
2800 }
2801 #if 0
2802 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2803 sanity check once the issue is solved. */
2804 else
2805 /* Addresses of conversions and SSA_NAMEs (and many other things)
2806 are not defined. Check that we did not forget to drop the
2807 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2810 #endif
2812 /* In case both args are comparisons but with different comparison
2813 code, try to swap the comparison operands of one arg to produce
2814 a match and compare that variant. */
2818 {
2826 }
2829 {
2830 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2832 ;
2834 {
2835 /* If we are interested in comparing addresses ignore
2836 MEM_REF wrappings of the base that can appear just for
2837 TBAA reasons. */
2851 }
2852 else
2854 }
2856 /* When not checking adddresses, this is needed for conversions and for
2857 COMPONENT_REF. Might as well play it safe and always test this. */
2864 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2865 We don't care about side effects in that case because the SAVE_EXPR
2866 takes care of that for us. In all other cases, two expressions are
2867 equal if they have no side effects. If we have two identical
2868 expressions with side effects that should be treated the same due
2869 to the only side effects being identical SAVE_EXPR's, that will
2870 be detected in the recursive calls below.
2871 If we are taking an invariant address of two identical objects
2872 they are necessarily equal as well. */
2879 /* Next handle constant cases, those for which we can return 1 even
2880 if ONLY_CONST is set. */
2883 {
2897 {
2898 /* If we do not distinguish between signed and unsigned zero,
2899 consider them equal. */
2902 }
2906 {
2913 {
2917 }
2919 }
2923 flags)
2925 flags));
2936 flags | OEP_ADDRESS_OF
2939 /* In GIMPLE empty constructors are allowed in initializers of
2940 aggregates. */
2945 }
2950 /* Define macros to test an operand from arg0 and arg1 for equality and a
2951 variant that allows null and views null as being different from any
2952 non-null value. In the latter case, if either is null, the both
2953 must be; otherwise, do the normal comparison. */
2954 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2955 TREE_OPERAND (arg1, N), flags)
2957 #define OP_SAME_WITH_NULL(N) \
2958 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2959 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2962 {
2964 /* Two conversions are equal only if signedness and modes match. */
2966 {
2967 CASE_CONVERT:
2975 }
2985 /* For commutative ops, allow the other order. */
2993 /* If either of the pointer (or reference) expressions we are
2994 dereferencing contain a side effect, these cannot be equal,
2995 but their addresses can be. */
3002 {
3019 {
3020 /* Require equal access sizes */
3026 flags)))
3028 /* Verify that accesses are TBAA compatible. */
3037 /* Verify that alignment is compatible. */
3041 }
3044 /* TARGET_MEM_REF require equal extra operands. */
3052 /* Operands 2 and 3 may be null.
3053 Compare the array index by value if it is constant first as we
3054 may have different types but same value here. */
3065 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3066 may be NULL when we're called to compare MEM_EXPRs. */
3081 }
3085 {
3087 /* Be sure we pass right ADDRESS_OF flag. */
3105 /* The multiplcation operands are commutative. */
3106 /* FALLTHRU */
3114 /* Otherwise take into account this is a commutative operation. */
3127 }
3131 {
3135 /* If not both CALL_EXPRs are either internal or normal function
3136 functions, then they are not equal. */
3139 {
3140 /* If the CALL_EXPRs call different internal functions, then they
3141 are not equal. */
3144 }
3145 else
3146 {
3147 /* If the CALL_EXPRs call different functions, then they are not
3148 equal. */
3150 flags))
3152 }
3154 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3155 {
3159 else
3163 }
3165 /* Now see if all the arguments are the same. */
3166 {
3177 /* If we get here and both argument lists are exhausted
3178 then the CALL_EXPRs are equal. */
3180 }
3183 }
3186 /* Consider __builtin_sqrt equal to sqrt. */
3194 {
3195 /* In GIMPLE constructors are used only to build vectors from
3196 elements. Individual elements in the constructor must be
3197 indexed in increasing order and form an initial sequence.
3199 We make no effort to compare constructors in generic.
3200 (see sem_variable::equals in ipa-icf which can do so for
3201 constants). */
3206 /* Be sure that vectors constructed have the same representation.
3207 We only tested element precision and modes to match.
3208 Vectors may be BLKmode and thus also check that the number of
3209 parts match. */
3222 {
3227 /* In GIMPLE the indexes can be either NULL or matching i.
3228 Double check this so we won't get false
3229 positives for GENERIC. */
3237 }
3239 }
3244 }
3246 #undef OP_SAME
3247 #undef OP_SAME_WITH_NULL
3248 }
3249 \f
3250 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3251 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3253 When in doubt, return 0. */
3255 static int
3257 {
3269 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3270 and see if the inner values are the same. This removes any
3271 signedness comparison, which doesn't matter here. */
3278 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3279 actual comparison operand, ARG0.
3281 First throw away any conversions to wider types
3282 already present in the operands. */
3291 {
3294 /* Make sure shorter operand is extended the right way
3295 to match the longer operand. */
3301 }
3304 }
3305 \f
3306 /* See if ARG is an expression that is either a comparison or is performing
3307 arithmetic on comparisons. The comparisons must only be comparing
3308 two different values, which will be stored in *CVAL1 and *CVAL2; if
3309 they are nonzero it means that some operands have already been found.
3310 No variables may be used anywhere else in the expression except in the
3311 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3312 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3314 If this is true, return 1. Otherwise, return zero. */
3316 static int
3318 {
3322 /* We can handle some of the tcc_expression cases here. */
3332 {
3333 /* If we've already found a CVAL1 or CVAL2, this expression is
3334 two complex to handle. */
3340 }
3343 {
3366 /* First see if we can handle the first operand, then the second. For
3367 the second operand, we know *CVAL1 can't be zero. It must be that
3368 one side of the comparison is each of the values; test for the
3369 case where this isn't true by failing if the two operands
3370 are the same. */
3379 ;
3383 ;
3384 else
3388 ;
3392 ;
3393 else
3400 }
3401 }
3402 \f
3403 /* ARG is a tree that is known to contain just arithmetic operations and
3404 comparisons. Evaluate the operations in the tree substituting NEW0 for
3405 any occurrence of OLD0 as an operand of a comparison and likewise for
3406 NEW1 and OLD1. */
3408 static tree
3411 {
3416 /* We can handle some of the tcc_expression cases here. */
3424 {
3439 {
3458 }
3459 /* Fall through - ??? */
3462 {
3466 /* We need to check both for exact equality and tree equality. The
3467 former will be true if the operand has a side-effect. In that
3468 case, we know the operand occurred exactly once. */
3481 }
3485 }
3486 }
3487 \f
3488 /* Return a tree for the case when the result of an expression is RESULT
3489 converted to TYPE and OMITTED was previously an operand of the expression
3490 but is now not needed (e.g., we folded OMITTED * 0).
3492 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3493 the conversion of RESULT to TYPE. */
3495 tree
3497 {
3500 /* If the resulting operand is an empty statement, just return the omitted
3501 statement casted to void. */
3511 }
3513 /* Return a tree for the case when the result of an expression is RESULT
3514 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3515 of the expression but are now not needed.
3517 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3518 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3519 evaluated before OMITTED2. Otherwise, if neither has side effects,
3520 just do the conversion of RESULT to TYPE. */
3522 tree
3525 {
3534 }
3536 \f
3537 /* Return a simplified tree node for the truth-negation of ARG. This
3538 never alters ARG itself. We assume that ARG is an operation that
3539 returns a truth value (0 or 1).
3541 FIXME: one would think we would fold the result, but it causes
3542 problems with the dominator optimizer. */
3544 static tree
3546 {
3551 /* If this is a comparison, we can simply invert it, except for
3552 floating-point non-equality comparisons, in which case we just
3553 enclose a TRUTH_NOT_EXPR around what we have. */
3556 {
3559 && flag_trapping_math
3570 }
3573 {
3592 /* Here we can invert either operand. We invert the first operand
3593 unless the second operand is a TRUTH_NOT_EXPR in which case our
3594 result is the XOR of the first operand with the inside of the
3595 negation of the second operand. */
3600 else
3623 {
3630 /* A COND_EXPR may have a throw as one operand, which
3631 then has void type. Just leave void operands
3632 as they are. */
3638 }
3650 CASE_CONVERT:
3654 /* ... fall through ... */
3676 }
3677 }
3679 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3680 assume that ARG is an operation that returns a truth value (0 or 1
3681 for scalars, 0 or -1 for vectors). Return the folded expression if
3682 folding is successful. Otherwise, return NULL_TREE. */
3684 static tree
3686 {
3689 ? BIT_NOT_EXPR
3692 }
3694 /* Return a simplified tree node for the truth-negation of ARG. This
3695 never alters ARG itself. We assume that ARG is an operation that
3696 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3698 tree
3700 {
3706 ? BIT_NOT_EXPR
3709 }
3711 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3712 with code CODE. This optimization is unsafe. */
3713 static tree
3716 {
3720 /* (A / C) +- (B / C) -> (A +- B) / C. */
3730 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3735 {
3747 }
3750 }
3751 \f
3752 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3753 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3754 and uses reverse storage order if REVERSEP is nonzero. */
3756 static tree
3760 {
3764 {
3771 }
3786 }
3788 /* Optimize a bit-field compare.
3790 There are two cases: First is a compare against a constant and the
3791 second is a comparison of two items where the fields are at the same
3792 bit position relative to the start of a chunk (byte, halfword, word)
3793 large enough to contain it. In these cases we can avoid the shift
3794 implicit in bitfield extractions.
3796 For constants, we emit a compare of the shifted constant with the
3797 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3798 compared. For two fields at the same position, we do the ANDs with the
3799 similar mask and compare the result of the ANDs.
3801 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3802 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3803 are the left and right operands of the comparison, respectively.
3805 If the optimization described above can be done, we return the resulting
3806 tree. Otherwise we return zero. */
3808 static tree
3811 {
3814 tree unsigned_type;
3821 tree mask;
3822 tree offset;
3824 /* Get all the information about the extractions being done. If the bit size
3825 if the same as the size of the underlying object, we aren't doing an
3826 extraction at all and so can do nothing. We also don't want to
3827 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3828 then will no longer be able to replace it. */
3837 else
3838 {
3839 /* If this is not a constant, we can only do something if bit positions,
3840 sizes, signedness and storage order are the same. */
3841 rinner
3849 }
3851 /* See if we can find a mode to refer to this field. We should be able to,
3852 but fail if we can't. */
3861 /* Set signed and unsigned types of the precision of this mode for the
3862 shifts below. */
3865 /* Compute the bit position and size for the new reference and our offset
3866 within it. If the new reference is the same size as the original, we
3867 won't optimize anything, so return zero. */
3877 /* Make the mask to be used against the extracted field. */
3884 /* If not comparing with constant, just rework the comparison
3885 and return. */
3889 unsigned_type,
3892 mask),
3895 unsigned_type,
3898 mask));
3900 /* Otherwise, we are handling the constant case. See if the constant is too
3901 big for the field. Warn and return a tree for 0 (false) if so. We do
3902 this not only for its own sake, but to avoid having to test for this
3903 error case below. If we didn't, we might generate wrong code.
3905 For unsigned fields, the constant shifted right by the field length should
3906 be all zero. For signed fields, the high-order bits should agree with
3907 the sign bit. */
3910 {
3912 {
3916 }
3917 }
3918 else
3919 {
3922 {
3926 }
3927 }
3929 /* Single-bit compares should always be against zero. */
3931 {
3934 }
3936 /* Make a new bitfield reference, shift the constant over the
3937 appropriate number of bits and mask it with the computed mask
3938 (in case this was a signed field). If we changed it, make a new one. */
3940 lreversep);
3946 mask);
3951 }
3952 \f
3953 /* Subroutine for fold_truth_andor_1: decode a field reference.
3955 If EXP is a comparison reference, we return the innermost reference.
3957 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
3958 set to the starting bit number.
3960 If the innermost field can be completely contained in a mode-sized
3961 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
3963 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
3964 otherwise it is not changed.
3966 *PUNSIGNEDP is set to the signedness of the field.
3968 *PREVERSEP is set to the storage order of the field.
3970 *PMASK is set to the mask used. This is either contained in a
3971 BIT_AND_EXPR or derived from the width of the field.
3973 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
3975 Return 0 if this is not a component reference or is one that we can't
3976 do anything with. */
3978 static tree
3983 {
3987 tree unsigned_type;
3990 /* All the optimizations using this function assume integer fields.
3991 There are problems with FP fields since the type_for_size call
3992 below can fail for, e.g., XFmode. */
3996 /* We are interested in the bare arrangement of bits, so strip everything
3997 that doesn't affect the machine mode. However, record the type of the
3998 outermost expression if it may matter below. */
4005 {
4011 }
4020 /* If the number of bits in the reference is the same as the bitsize of
4021 the outer type, then the outer type gives the signedness. Otherwise
4022 (in case of a small bitfield) the signedness is unchanged. */
4026 /* Compute the mask to access the bitfield. */
4035 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4043 }
4045 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4046 bit positions and MASK is SIGNED. */
4048 static int
4050 {
4054 /* If this function returns true when the type of the mask is
4055 UNSIGNED, then there will be errors. In particular see
4056 gcc.c-torture/execute/990326-1.c. There does not appear to be
4057 any documentation paper trail as to why this is so. But the pre
4058 wide-int worked with that restriction and it has been preserved
4059 here. */
4064 }
4066 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4067 represents the sign bit of EXP's type. If EXP represents a sign
4068 or zero extension, also test VAL against the unextended type.
4069 The return value is the (sub)expression whose sign bit is VAL,
4070 or NULL_TREE otherwise. */
4072 tree
4074 {
4076 tree t;
4078 /* Tree EXP must have an integral type. */
4083 /* Tree VAL must be an integer constant. */
4092 /* Handle extension from a narrower type. */
4098 }
4100 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4101 to be evaluated unconditionally. */
4103 static int
4105 {
4106 /* Strip any conversions that don't change the machine mode. */
4115 /* Don't regard global variables as simple. They may be
4116 allocated in ways unknown to the compiler (shared memory,
4117 #pragma weak, etc). */
4120 /* Weakrefs are not safe to be read, since they can be NULL.
4121 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4122 have DECL_WEAK flag set. */
4124 /* Loading a static variable is unduly expensive, but global
4125 registers aren't expensive. */
4127 }
4129 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4130 to be evaluated unconditionally.
4131 I addition to simple_operand_p, we assume that comparisons, conversions,
4132 and logic-not operations are simple, if their operands are simple, too. */
4134 static bool
4136 {
4156 }
4158 \f
4159 /* The following functions are subroutines to fold_range_test and allow it to
4160 try to change a logical combination of comparisons into a range test.
4162 For example, both
4163 X == 2 || X == 3 || X == 4 || X == 5
4164 and
4165 X >= 2 && X <= 5
4166 are converted to
4167 (unsigned) (X - 2) <= 3
4169 We describe each set of comparisons as being either inside or outside
4170 a range, using a variable named like IN_P, and then describe the
4171 range with a lower and upper bound. If one of the bounds is omitted,
4172 it represents either the highest or lowest value of the type.
4174 In the comments below, we represent a range by two numbers in brackets
4175 preceded by a "+" to designate being inside that range, or a "-" to
4176 designate being outside that range, so the condition can be inverted by
4177 flipping the prefix. An omitted bound is represented by a "-". For
4178 example, "- [-, 10]" means being outside the range starting at the lowest
4179 possible value and ending at 10, in other words, being greater than 10.
4180 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4181 always false.
4183 We set up things so that the missing bounds are handled in a consistent
4184 manner so neither a missing bound nor "true" and "false" need to be
4185 handled using a special case. */
4187 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4188 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4189 and UPPER1_P are nonzero if the respective argument is an upper bound
4190 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4191 must be specified for a comparison. ARG1 will be converted to ARG0's
4192 type if both are specified. */
4194 static tree
4197 {
4198 tree tem;
4202 /* If neither arg represents infinity, do the normal operation.
4203 Else, if not a comparison, return infinity. Else handle the special
4204 comparison rules. Note that most of the cases below won't occur, but
4205 are handled for consistency. */
4208 {
4213 }
4218 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4219 for neither. In real maths, we cannot assume open ended ranges are
4220 the same. But, this is computer arithmetic, where numbers are finite.
4221 We can therefore make the transformation of any unbounded range with
4222 the value Z, Z being greater than any representable number. This permits
4223 us to treat unbounded ranges as equal. */
4227 {
4248 }
4251 }
4252 \f
4253 /* Helper routine for make_range. Perform one step for it, return
4254 new expression if the loop should continue or NULL_TREE if it should
4255 stop. */
4257 tree
4261 {
4267 {
4269 /* We can only do something if the range is testing for zero. */
4278 /* We can only do something if the range is testing for zero
4279 and if the second operand is an integer constant. Note that
4280 saying something is "in" the range we make is done by
4281 complementing IN_P since it will set in the initial case of
4282 being not equal to zero; "out" is leaving it alone. */
4289 {
4310 }
4312 /* If this is an unsigned comparison, we also know that EXP is
4313 greater than or equal to zero. We base the range tests we make
4314 on that fact, so we record it here so we can parse existing
4315 range tests. We test arg0_type since often the return type
4316 of, e.g. EQ_EXPR, is boolean. */
4318 {
4322 NULL_TREE))
4327 /* If the high bound is missing, but we have a nonzero low
4328 bound, reverse the range so it goes from zero to the low bound
4329 minus 1. */
4331 {
4336 }
4337 }
4345 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4346 low and high are non-NULL, then normalize will DTRT. */
4349 {
4354 }
4356 /* (-x) IN [a,b] -> x in [-b, -a] */
4368 /* ~ X -> -X - 1 */
4377 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4378 move a constant to the other side. */
4383 /* If EXP is signed, any overflow in the computation is undefined,
4384 so we don't worry about it so long as our computations on
4385 the bounds don't overflow. For unsigned, overflow is defined
4386 and this is exactly the right thing. */
4398 normalize:
4399 /* Check for an unsigned range which has wrapped around the maximum
4400 value thus making n_high < n_low, and normalize it. */
4402 {
4408 /* If the range is of the form +/- [ x+1, x ], we won't
4409 be able to normalize it. But then, it represents the
4410 whole range or the empty set, so make it
4411 +/- [ -, - ]. */
4415 else
4417 }
4418 else
4426 CASE_CONVERT:
4444 /* If we're converting arg0 from an unsigned type, to exp,
4445 a signed type, we will be doing the comparison as unsigned.
4446 The tests above have already verified that LOW and HIGH
4447 are both positive.
4449 So we have to ensure that we will handle large unsigned
4450 values the same way that the current signed bounds treat
4451 negative values. */
4454 {
4455 tree high_positive;
4456 tree equiv_type;
4457 /* For fixed-point modes, we need to pass the saturating flag
4458 as the 2nd parameter. */
4460 equiv_type
4463 else
4464 equiv_type
4467 /* A range without an upper bound is, naturally, unbounded.
4468 Since convert would have cropped a very large value, use
4469 the max value for the destination type. */
4470 high_positive
4477 high_positive),
4480 /* If the low bound is specified, "and" the range with the
4481 range for which the original unsigned value will be
4482 positive. */
4484 {
4487 integer_zero_node),
4488 high_positive))
4492 }
4493 else
4494 {
4495 /* Otherwise, "or" the range with the range of the input
4496 that will be interpreted as negative. */
4499 integer_zero_node),
4500 high_positive))
4504 }
4505 }
4514 }
4515 }
4517 /* Given EXP, a logical expression, set the range it is testing into
4518 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4519 actually being tested. *PLOW and *PHIGH will be made of the same
4520 type as the returned expression. If EXP is not a comparison, we
4521 will most likely not be returning a useful value and range. Set
4522 *STRICT_OVERFLOW_P to true if the return value is only valid
4523 because signed overflow is undefined; otherwise, do not change
4524 *STRICT_OVERFLOW_P. */
4526 tree
4529 {
4537 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4538 and see if we can refine the range. Some of the cases below may not
4539 happen, but it doesn't seem worth worrying about this. We "continue"
4540 the outer loop when we've changed something; otherwise we "break"
4541 the switch, which will "break" the while. */
4547 {
4553 {
4561 }
4570 }
4572 /* If EXP is a constant, we can evaluate whether this is true or false. */
4574 {
4581 }
4585 }
4586 \f
4587 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4588 type, TYPE, return an expression to test if EXP is in (or out of, depending
4589 on IN_P) the range. Return 0 if the test couldn't be created. */
4591 tree
4594 {
4597 /* Disable this optimization for function pointer expressions
4598 on targets that require function pointer canonicalization. */
4605 {
4611 }
4629 {
4631 {
4635 }
4637 }
4639 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4641 {
4645 {
4647 {
4650 etype
4652 else
4655 }
4658 }
4659 }
4661 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4662 This requires wrap-around arithmetics for the type of the expression.
4663 First make sure that arithmetics in this type is valid, then make sure
4664 that it wraps around. */
4670 {
4673 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4674 for the type in question, as we rely on this here. */
4684 else
4686 }
4696 {
4698 {
4703 }
4705 }
4713 }
4714 \f
4715 /* Return the predecessor of VAL in its type, handling the infinite case. */
4717 static tree
4719 {
4725 else
4728 }
4730 /* Return the successor of VAL in its type, handling the infinite case. */
4732 static tree
4734 {
4740 else
4743 }
4745 /* Given two ranges, see if we can merge them into one. Return 1 if we
4746 can, 0 if we can't. Set the output range into the specified parameters. */
4748 bool
4751 {
4755 tree tem;
4765 /* Make range 0 be the range that starts first, or ends last if they
4766 start at the same value. Swap them if it isn't. */
4769 || (lowequal
4772 {
4776 }
4778 /* Now flag two cases, whether the ranges are disjoint or whether the
4779 second range is totally subsumed in the first. Note that the tests
4780 below are simplified by the ones above. */
4786 /* We now have four cases, depending on whether we are including or
4787 excluding the two ranges. */
4789 {
4790 /* If they don't overlap, the result is false. If the second range
4791 is a subset it is the result. Otherwise, the range is from the start
4792 of the second to the end of the first. */
4797 else
4799 }
4802 {
4803 /* If they don't overlap, the result is the first range. If they are
4804 equal, the result is false. If the second range is a subset of the
4805 first, and the ranges begin at the same place, we go from just after
4806 the end of the second range to the end of the first. If the second
4807 range is not a subset of the first, or if it is a subset and both
4808 ranges end at the same place, the range starts at the start of the
4809 first range and ends just before the second range.
4810 Otherwise, we can't describe this as a single range. */
4816 {
4821 {
4822 /* We are in the weird situation where high0 > high1 but
4823 high1 has no successor. Punt. */
4825 }
4826 }
4828 {
4833 {
4834 /* low0 < low1 but low1 has no predecessor. Punt. */
4836 }
4837 }
4838 else
4840 }
4843 {
4844 /* If they don't overlap, the result is the second range. If the second
4845 is a subset of the first, the result is false. Otherwise,
4846 the range starts just after the first range and ends at the
4847 end of the second. */
4852 else
4853 {
4858 {
4859 /* high1 > high0 but high0 has no successor. Punt. */
4861 }
4862 }
4863 }
4865 else
4866 {
4867 /* The case where we are excluding both ranges. Here the complex case
4868 is if they don't overlap. In that case, the only time we have a
4869 range is if they are adjacent. If the second is a subset of the
4870 first, the result is the first. Otherwise, the range to exclude
4871 starts at the beginning of the first range and ends at the end of the
4872 second. */
4874 {
4879 else
4880 {
4881 /* Canonicalize - [min, x] into - [-, x]. */
4884 {
4889 /* FALLTHROUGH */
4902 }
4904 /* Canonicalize - [x, max] into - [x, -]. */
4907 {
4912 /* FALLTHROUGH */
4928 }
4930 /* The ranges might be also adjacent between the maximum and
4931 minimum values of the given type. For
4932 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4933 return + [x + 1, y - 1]. */
4935 {
4942 }
4943 else
4945 }
4946 }
4949 else
4951 }
4955 }
4956 \f
4958 /* Subroutine of fold, looking inside expressions of the form
4959 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
4960 of the COND_EXPR. This function is being used also to optimize
4961 A op B ? C : A, by reversing the comparison first.
4963 Return a folded expression whose code is not a COND_EXPR
4964 anymore, or NULL_TREE if no folding opportunity is found. */
4966 static tree
4969 {
4974 tree tem;
4979 /* If we have A op 0 ? A : -A, consider applying the following
4980 transformations:
4982 A == 0? A : -A same as -A
4983 A != 0? A : -A same as A
4984 A >= 0? A : -A same as abs (A)
4985 A > 0? A : -A same as abs (A)
4986 A <= 0? A : -A same as -abs (A)
4987 A < 0? A : -A same as -abs (A)
4989 None of these transformations work for modes with signed
4990 zeros. If A is +/-0, the first two transformations will
4991 change the sign of the result (from +0 to -0, or vice
4992 versa). The last four will fix the sign of the result,
4993 even though the original expressions could be positive or
4994 negative, depending on the sign of A.
4996 Note that all these transformations are correct if A is
4997 NaN, since the two alternatives (A and -A) are also NaNs. */
5004 /* In the case that A is of the form X-Y, '-A' (arg2) may
5005 have already been folded to Y-X, check for that. */
5013 {
5027 /* Fall through. */
5047 }
5049 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5050 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5051 both transformations are correct when A is NaN: A != 0
5052 is then true, and A == 0 is false. */
5056 {
5061 }
5063 /* Try some transformations of A op B ? A : B.
5065 A == B? A : B same as B
5066 A != B? A : B same as A
5067 A >= B? A : B same as max (A, B)
5068 A > B? A : B same as max (B, A)
5069 A <= B? A : B same as min (A, B)
5070 A < B? A : B same as min (B, A)
5072 As above, these transformations don't work in the presence
5073 of signed zeros. For example, if A and B are zeros of
5074 opposite sign, the first two transformations will change
5075 the sign of the result. In the last four, the original
5076 expressions give different results for (A=+0, B=-0) and
5077 (A=-0, B=+0), but the transformed expressions do not.
5079 The first two transformations are correct if either A or B
5080 is a NaN. In the first transformation, the condition will
5081 be false, and B will indeed be chosen. In the case of the
5082 second transformation, the condition A != B will be true,
5083 and A will be chosen.
5085 The conversions to max() and min() are not correct if B is
5086 a number and A is not. The conditions in the original
5087 expressions will be false, so all four give B. The min()
5088 and max() versions would give a NaN instead. */
5091 /* Avoid these transformations if the COND_EXPR may be used
5092 as an lvalue in the C++ front-end. PR c++/19199. */
5093 && (in_gimple_form
5099 {
5104 /* Avoid adding NOP_EXPRs in case this is an lvalue. */
5106 {
5110 }
5113 {
5122 /* In C++ a ?: expression can be an lvalue, so put the
5123 operand which will be used if they are equal first
5124 so that we can convert this back to the
5125 corresponding COND_EXPR. */
5127 {
5136 }
5143 {
5152 }
5167 }
5168 }
5170 /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
5171 we might still be able to simplify this. For example,
5172 if C1 is one less or one more than C2, this might have started
5173 out as a MIN or MAX and been transformed by this function.
5174 Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
5180 {
5184 /* We can replace A with C1 in this case. */
5189 /* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
5190 MIN_EXPR, to preserve the signedness of the comparison. */
5192 OEP_ONLY_CONST)
5196 OEP_ONLY_CONST))
5197 {
5200 arg2));
5203 }
5207 /* If C1 is C2 - 1, this is min(A, C2), with the same care
5208 as above. */
5210 OEP_ONLY_CONST)
5214 OEP_ONLY_CONST))
5215 {
5218 arg2));
5221 }
5225 /* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
5226 MAX_EXPR, to preserve the signedness of the comparison. */
5228 OEP_ONLY_CONST)
5232 OEP_ONLY_CONST))
5233 {
5236 arg2));
5238 }
5242 /* If C1 is C2 + 1, this is max(A, C2), with the same care as above. */
5244 OEP_ONLY_CONST)
5248 OEP_ONLY_CONST))
5249 {
5252 arg2));
5254 }
5260 }
5263 }
5266 \f
5267 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5268 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5269 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5270 false) >= 2)
5271 #endif
5273 /* EXP is some logical combination of boolean tests. See if we can
5274 merge it into some range test. Return the new tree if so. */
5276 static tree
5279 {
5295 /* If this is an OR operation, invert both sides; we will invert
5296 again at the end. */
5300 /* If both expressions are the same, if we can merge the ranges, and we
5301 can build the range test, return it or it inverted. If one of the
5302 ranges is always true or always false, consider it to be the same
5303 expression as the other. */
5311 {
5315 }
5317 /* On machines where the branch cost is expensive, if this is a
5318 short-circuited branch and the underlying object on both sides
5319 is the same, make a non-short-circuit operation. */
5325 {
5326 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5327 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5328 which cases we can't do this. */
5336 {
5345 {
5348 WARN_STRICT_OVERFLOW_COMPARISON);
5352 }
5353 }
5354 }
5357 }
5358 \f
5359 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5360 bit value. Arrange things so the extra bits will be set to zero if and
5361 only if C is signed-extended to its full width. If MASK is nonzero,
5362 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5364 static tree
5366 {
5369 tree temp;
5374 /* We work by getting just the sign bit into the low-order bit, then
5375 into the high-order bit, then sign-extend. We then XOR that value
5376 with C. */
5379 /* We must use a signed type in order to get an arithmetic right shift.
5380 However, we must also avoid introducing accidental overflows, so that
5381 a subsequent call to integer_zerop will work. Hence we must
5382 do the type conversion here. At this point, the constant is either
5383 zero or one, and the conversion to a signed type can never overflow.
5384 We could get an overflow if this conversion is done anywhere else. */
5393 /* If necessary, convert the type back to match the type of C. */
5398 }
5399 \f
5400 /* For an expression that has the form
5401 (A && B) || ~B
5402 or
5403 (A || B) && ~B,
5404 we can drop one of the inner expressions and simplify to
5405 A || ~B
5406 or
5407 A && ~B
5408 LOC is the location of the resulting expression. OP is the inner
5409 logical operation; the left-hand side in the examples above, while CMPOP
5410 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5411 removing a condition that guards another, as in
5412 (A != NULL && A->...) || A == NULL
5413 which we must not transform. If RHS_ONLY is true, only eliminate the
5414 right-most operand of the inner logical operation. */
5416 static tree
5419 {
5437 {
5440 {
5443 }
5444 }
5446 {
5449 {
5452 }
5453 }
5468 }
5470 /* Find ways of folding logical expressions of LHS and RHS:
5471 Try to merge two comparisons to the same innermost item.
5472 Look for range tests like "ch >= '0' && ch <= '9'".
5473 Look for combinations of simple terms on machines with expensive branches
5474 and evaluate the RHS unconditionally.
5476 For example, if we have p->a == 2 && p->b == 4 and we can make an
5477 object large enough to span both A and B, we can do this with a comparison
5478 against the object ANDed with the a mask.
5480 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5481 operations to do this with one comparison.
5483 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5484 function and the one above.
5486 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5487 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5489 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5490 two operands.
5492 We return the simplified tree or 0 if no optimization is possible. */
5494 static tree
5497 {
5498 /* If this is the "or" of two comparisons, we can do something if
5499 the comparisons are NE_EXPR. If this is the "and", we can do something
5500 if the comparisons are EQ_EXPR. I.e.,
5501 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5503 WANTED_CODE is this operation code. For single bit fields, we can
5504 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5505 comparison for one-bit fields. */
5526 /* Start by getting the comparison codes. Fail if anything is volatile.
5527 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5528 it were surrounded with a NE_EXPR. */
5537 {
5541 }
5544 {
5548 }
5559 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5562 {
5565 {
5570 }
5573 {
5579 }
5580 }
5585 /* If the RHS can be evaluated unconditionally and its operands are
5586 simple, it wins to evaluate the RHS unconditionally on machines
5587 with expensive branches. In this case, this isn't a comparison
5588 that can be merged. */
5595 {
5596 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5607 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5617 }
5619 /* See if the comparisons can be merged. Then get all the parameters for
5620 each side. */
5645 /* It must be true that the inner operation on the lhs of each
5646 comparison must be the same if we are to be able to do anything.
5647 Then see if we have constants. If not, the same must be true for
5648 the rhs's. */
5657 {
5660 }
5665 else
5668 /* If either comparison code is not correct for our logical operation,
5669 fail. However, we can convert a one-bit comparison against zero into
5670 the opposite comparison against that bit being set in the field. */
5674 {
5676 {
5677 /* Make the left operand unsigned, since we are only interested
5678 in the value of one bit. Otherwise we are doing the wrong
5679 thing below. */
5682 }
5683 else
5685 }
5687 /* This is analogous to the code for l_const above. */
5689 {
5691 {
5694 }
5695 else
5697 }
5699 /* See if we can find a mode that contains both fields being compared on
5700 the left. If we can't, fail. Otherwise, update all constants and masks
5701 to be relative to a field of that size. */
5706 volatilep);
5716 {
5719 }
5727 {
5734 {
5738 }
5739 }
5741 {
5748 {
5752 }
5753 }
5755 /* If the right sides are not constant, do the same for it. Also,
5756 disallow this optimization if a size or signedness mismatch occurs
5757 between the left and right sides. */
5759 {
5762 /* Make sure the two fields on the right
5763 correspond to the left without being swapped. */
5771 volatilep);
5781 {
5784 }
5793 /* Make a mask that corresponds to both fields being compared.
5794 Do this for both items being compared. If the operands are the
5795 same size and the bits being compared are in the same position
5796 then we can do this by masking both and comparing the masked
5797 results. */
5801 {
5813 }
5815 /* There is still another way we can do something: If both pairs of
5816 fields being compared are adjacent, we may be able to make a wider
5817 field containing them both.
5819 Note that we still must mask the lhs/rhs expressions. Furthermore,
5820 the mask must be shifted to account for the shift done by
5821 make_bit_field_ref. */
5826 {
5827 tree type;
5843 /* Convert to the smaller type before masking out unwanted bits. */
5846 {
5848 {
5852 }
5854 {
5858 }
5859 }
5868 }
5871 }
5873 /* Handle the case of comparisons with constants. If there is something in
5874 common between the masks, those bits of the constants must be the same.
5875 If not, the condition is always false. Test for this to avoid generating
5876 incorrect code below. */
5881 {
5883 {
5886 }
5887 else
5888 {
5891 }
5892 }
5894 /* Construct the expression we will return. First get the component
5895 reference we will make. Unless the mask is all ones the width of
5896 that field, perform the mask operation. Then compare with the
5897 merged constant. */
5907 }
5908 \f
5909 /* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
5910 constant. */
5912 static tree
5915 {
5918 tree comp_const;
5919 tree minmax_const;
5921 tree inner;
5932 /* If something does not permit us to optimize, return the original tree. */
5940 /* Now handle all the various comparison codes. We only handle EQ_EXPR
5941 and GT_EXPR, doing the rest with recursive calls using logical
5942 simplifications. */
5944 {
5946 {
5947 tree tem
5954 }
5957 return
5959 optimize_minmax_comparison
5961 optimize_minmax_comparison
5966 /* MAX (X, 0) == 0 -> X <= 0 */
5970 /* MAX (X, 0) == 5 -> X == 5 */
5974 /* MAX (X, 0) == -1 -> false */
5978 /* MIN (X, 0) == 0 -> X >= 0 */
5982 /* MIN (X, 0) == 5 -> false */
5985 else
5986 /* MIN (X, 0) == -1 -> X == -1 */
5991 /* MAX (X, 0) > 0 -> X > 0
5992 MAX (X, 0) > 5 -> X > 5 */
5996 /* MAX (X, 0) > -1 -> true */
6000 /* MIN (X, 0) > 0 -> false
6001 MIN (X, 0) > 5 -> false */
6004 else
6005 /* MIN (X, 0) > -1 -> X > -1 */
6010 }
6011 }
6012 \f
6013 /* T is an integer expression that is being multiplied, divided, or taken a
6014 modulus (CODE says which and what kind of divide or modulus) by a
6015 constant C. See if we can eliminate that operation by folding it with
6016 other operations already in T. WIDE_TYPE, if non-null, is a type that
6017 should be used for the computation if wider than our type.
6019 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6020 (X * 2) + (Y * 4). We must, however, be assured that either the original
6021 expression would not overflow or that overflow is undefined for the type
6022 in the language in question.
6024 If we return a non-null expression, it is an equivalent form of the
6025 original computation, but need not be in the original type.
6027 We set *STRICT_OVERFLOW_P to true if the return values depends on
6028 signed overflow being undefined. Otherwise we do not change
6029 *STRICT_OVERFLOW_P. */
6031 static tree
6034 {
6035 /* To avoid exponential search depth, refuse to allow recursion past
6036 three levels. Beyond that (1) it's highly unlikely that we'll find
6037 something interesting and (2) we've probably processed it before
6038 when we built the inner expression. */
6041 tree ret;
6046 depth++;
6048 depth--;
6051 }
6053 static tree
6056 {
6067 /* Don't deal with constants of zero here; they confuse the code below. */
6077 /* Note that we need not handle conditional operations here since fold
6078 already handles those cases. So just do arithmetic here. */
6080 {
6082 /* For a constant, we can always simplify if we are a multiply
6083 or (for divide and modulus) if it is a multiple of our constant. */
6086 {
6089 /* If the multiplication overflowed to INT_MIN then we lost sign
6090 information on it and a subsequent multiplication might
6091 spuriously overflow. See PR68142. */
6096 }
6100 /* If op0 is an expression ... */
6106 /* ... and has wrapping overflow, and its type is smaller
6107 than ctype, then we cannot pass through as widening. */
6112 /* ... or this is a truncation (t is narrower than op0),
6113 then we cannot pass through this narrowing. */
6116 /* ... or signedness changes for division or modulus,
6117 then we cannot pass through this conversion. */
6121 /* ... or has undefined overflow while the converted to
6122 type has not, we cannot do the operation in the inner type
6123 as that would introduce undefined overflow. */
6129 /* Pass the constant down and see if we can make a simplification. If
6130 we can, replace this expression with the inner simplification for
6131 possible later conversion to our or some other type. */
6136 code == MULT_EXPR
6138 strict_overflow_p))))
6143 /* If widening the type changes it from signed to unsigned, then we
6144 must avoid building ABS_EXPR itself as unsigned. */
6146 {
6150 {
6153 }
6155 }
6156 /* If the constant is negative, we cannot simplify this. */
6159 /* FALLTHROUGH */
6161 /* For division and modulus, type can't be unsigned, as e.g.
6162 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6163 For signed types, even with wrapping overflow, this is fine. */
6172 /* If widening the type changes the signedness, then we can't perform
6173 this optimization as that changes the result. */
6177 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6183 {
6190 }
6194 /* If the second operand is constant, this is a multiplication
6195 or floor division, by a power of two, so we can treat it that
6196 way unless the multiplier or divisor overflows. Signed
6197 left-shift overflow is implementation-defined rather than
6198 undefined in C90, so do not convert signed left shift into
6199 multiplication. */
6202 /* const_binop may not detect overflow correctly,
6203 so check for it explicitly here. */
6207 size_one_node,
6208 op1)))
6212 ctype,
6214 t1),
6219 /* See if we can eliminate the operation on both sides. If we can, we
6220 can return a new PLUS or MINUS. If we can't, the only remaining
6221 cases where we can do anything are if the second operand is a
6222 constant. */
6228 /* If not multiplication, we can only do this if both operands
6229 are divisible by c. */
6232 {
6237 }
6239 /* If this was a subtraction, negate OP1 and set it to be an addition.
6240 This simplifies the logic below. */
6242 {
6244 /* If OP1 was not easily negatable, the constant may be OP0. */
6246 {
6249 }
6250 }
6255 /* If either OP1 or C are negative, this optimization is not safe for
6256 some of the division and remainder types while for others we need
6257 to change the code. */
6259 {
6267 }
6269 /* If it's a multiply or a division/modulus operation of a multiple
6270 of our constant, do the operation and verify it doesn't overflow. */
6273 {
6276 /* We allow the constant to overflow with wrapping semantics. */
6280 }
6281 else
6284 /* If we have an unsigned type, we cannot widen the operation since it
6285 will change the result if the original computation overflowed. */
6289 /* If we were able to eliminate our operation from the first side,
6290 apply our operation to the second side and reform the PLUS. */
6294 /* The last case is if we are a multiply. In that case, we can
6295 apply the distributive law to commute the multiply and addition
6296 if the multiplication of the constants doesn't overflow
6297 and overflow is defined. With undefined overflow
6298 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6304 op1);
6309 /* We have a special case here if we are doing something like
6310 (C * 8) % 4 since we know that's zero. */
6313 /* If the multiplication can overflow we cannot optimize this. */
6317 {
6320 }
6322 /* ... fall through ... */
6326 /* If we can extract our operation from the LHS, do so and return a
6327 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6328 do something only if the second operand is a constant. */
6342 /* If these are the same operation types, we can associate them
6343 assuming no overflow. */
6345 {
6355 {
6360 }
6361 }
6363 /* If these operations "cancel" each other, we have the main
6364 optimizations of this pass, which occur when either constant is a
6365 multiple of the other, in which case we replace this with either an
6366 operation or CODE or TCODE.
6368 If we have an unsigned type, we cannot do this since it will change
6369 the result if the original computation overflowed. */
6376 {
6378 {
6385 }
6387 {
6394 }
6395 }
6400 }
6403 }
6404 \f
6405 /* Return a node which has the indicated constant VALUE (either 0 or
6406 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6407 and is of the indicated TYPE. */
6409 tree
6411 {
6420 else
6422 }
6425 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6426 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6427 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6428 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6429 COND is the first argument to CODE; otherwise (as in the example
6430 given here), it is the second argument. TYPE is the type of the
6431 original expression. Return NULL_TREE if no simplification is
6432 possible. */
6434 static tree
6439 {
6449 {
6453 /* If this operand throws an expression, then it does not make
6454 sense to try to perform a logical or arithmetic operation
6455 involving it. */
6460 }
6463 {
6468 }
6469 else
6470 /* Detect the case of mixing vector and scalar types - bail out. */
6476 /* This transformation is only worthwhile if we don't have to wrap ARG
6477 in a SAVE_EXPR and the operation can be simplified without recursing
6478 on at least one of the branches once its pushed inside the COND_EXPR. */
6487 {
6491 else
6493 }
6495 {
6499 else
6501 }
6503 /* Check that we have simplified at least one of the branches. */
6508 }
6510 \f
6511 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6513 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6514 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6515 ADDEND is the same as X.
6517 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6518 and finite. The problematic cases are when X is zero, and its mode
6519 has signed zeros. In the case of rounding towards -infinity,
6520 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6521 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6523 bool
6525 {
6529 /* Don't allow the fold with -fsignaling-nans. */
6533 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6537 /* In a vector or complex, we would need to check the sign of all zeros. */
6541 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6545 /* The mode has signed zeros, and we have to honor their sign.
6546 In this situation, there is only one case we can return true for.
6547 X - 0 is the same as X unless rounding towards -infinity is
6548 supported. */
6550 }
6552 /* Subroutine of fold() that optimizes comparisons of a division by
6553 a nonzero integer constant against an integer constant, i.e.
6554 X/C1 op C2.
6556 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6557 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6558 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6560 The function returns the constant folded tree if a simplification
6561 can be made, and NULL_TREE otherwise. */
6563 static tree
6566 {
6574 /* We have to do this the hard way to detect unsigned overflow.
6575 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6581 {
6586 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6590 }
6592 {
6596 {
6615 }
6616 }
6617 else
6618 {
6619 /* A negative divisor reverses the relational operators. */
6625 {
6644 }
6645 }
6648 {
6669 {
6672 }
6677 {
6680 }
6685 {
6688 }
6693 {
6696 }
6701 }
6704 }
6707 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6708 equality/inequality test, then return a simplified form of the test
6709 using a sign testing. Otherwise return NULL. TYPE is the desired
6710 result type. */
6712 static tree
6715 tree result_type)
6716 {
6717 /* If this is testing a single bit, we can optimize the test. */
6721 {
6722 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6723 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6727 /* This is only a win if casting to a signed type is cheap,
6728 i.e. when arg00's type is not a partial mode. */
6731 {
6734 result_type,
6737 }
6738 }
6741 }
6743 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6744 equality/inequality test, then return a simplified form of
6745 the test using shifts and logical operations. Otherwise return
6746 NULL. TYPE is the desired result type. */
6748 tree
6751 {
6752 /* If this is testing a single bit, we can optimize the test. */
6756 {
6765 /* First, see if we can fold the single bit test into a sign-bit
6766 test. */
6768 result_type);
6772 /* Otherwise we have (A & C) != 0 where C is a single bit,
6773 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6774 Similarly for (A & C) == 0. */
6776 /* If INNER is a right shift of a constant and it plus BITNUM does
6777 not overflow, adjust BITNUM and INNER. */
6783 {
6786 }
6788 /* If we are going to be able to omit the AND below, we must do our
6789 operations as unsigned. If we must use the AND, we have a choice.
6790 Normally unsigned is faster, but for some machines signed is. */
6808 /* Put the AND last so it can combine with more things. */
6811 /* Make sure to return the proper type. */
6815 }
6817 }
6819 /* Check whether we are allowed to reorder operands arg0 and arg1,
6820 such that the evaluation of arg1 occurs before arg0. */
6822 static bool
6824 {
6831 }
6833 /* Test whether it is preferable two swap two operands, ARG0 and
6834 ARG1, for example because ARG0 is an integer constant and ARG1
6835 isn't. If REORDER is true, only recommend swapping if we can
6836 evaluate the operands in reverse order. */
6838 bool
6840 {
6858 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6859 for commutative and comparison operators. Ensuring a canonical
6860 form allows the optimizers to find additional redundancies without
6861 having to explicitly check for both orderings. */
6867 /* Put SSA_NAMEs last. */
6873 /* Put variables last. */
6880 }
6883 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6884 means A >= Y && A != MAX, but in this case we know that
6885 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6887 static tree
6889 {
6896 else
6905 {
6908 }
6910 {
6913 }
6914 else
6921 {
6922 /* Convert the pointer types into integer before taking the difference. */
6926 }
6927 else
6934 }
6936 /* Fold a sum or difference of at least one multiplication.
6937 Returns the folded tree or NULL if no simplification could be made. */
6939 static tree
6942 {
6946 /* (A * C) +- (B * C) -> (A+-B) * C.
6947 (A * C) +- A -> A * (C+-1).
6948 We are most concerned about the case where C is a constant,
6949 but other combinations show up during loop reduction. Since
6950 it is not difficult, try all four possibilities. */
6953 {
6956 }
6958 {
6961 }
6962 else
6963 {
6964 /* We cannot generate constant 1 for fract. */
6969 }
6971 {
6974 }
6976 {
6978 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6979 the purpose of this canonicalization. */
6983 {
6986 }
6987 else
6989 }
6990 else
6991 {
6992 /* We cannot generate constant 1 for fract. */
6997 }
7009 /* No identical multiplicands; see if we can find a common
7010 power-of-two factor in non-power-of-two multiplies. This
7011 can help in multi-dimensional array access. */
7014 {
7017 tree maybe_same;
7021 /* Move min of absolute values to int11. */
7023 {
7028 }
7029 else
7033 /* The remainder should not be a constant, otherwise we
7034 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7035 increased the number of multiplications necessary. */
7037 {
7045 }
7046 }
7056 }
7058 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7059 specified by EXPR into the buffer PTR of length LEN bytes.
7060 Return the number of bytes placed in the buffer, or zero
7061 upon failure. */
7063 static int
7065 {
7079 {
7081 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7082 number of bytes. */
7086 {
7093 else
7095 }
7096 else
7101 }
7103 }
7106 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7107 specified by EXPR into the buffer PTR of length LEN bytes.
7108 Return the number of bytes placed in the buffer, or zero
7109 upon failure. */
7111 static int
7113 {
7117 FIXED_VALUE_TYPE value;
7133 }
7136 /* Subroutine of native_encode_expr. Encode the REAL_CST
7137 specified by EXPR into the buffer PTR of length LEN bytes.
7138 Return the number of bytes placed in the buffer, or zero
7139 upon failure. */
7141 static int
7143 {
7149 /* There are always 32 bits in each long, no matter the size of
7150 the hosts long. We handle floating point representations with
7151 up to 192 bits. */
7165 {
7170 {
7177 else
7179 }
7180 else
7186 }
7188 }
7190 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7191 specified by EXPR into the buffer PTR of length LEN bytes.
7192 Return the number of bytes placed in the buffer, or zero
7193 upon failure. */
7195 static int
7197 {
7199 tree part;
7214 }
7217 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7218 specified by EXPR into the buffer PTR of length LEN bytes.
7219 Return the number of bytes placed in the buffer, or zero
7220 upon failure. */
7222 static int
7224 {
7234 {
7236 {
7239 }
7250 }
7252 }
7255 /* Subroutine of native_encode_expr. Encode the STRING_CST
7256 specified by EXPR into the buffer PTR of length LEN bytes.
7257 Return the number of bytes placed in the buffer, or zero
7258 upon failure. */
7260 static int
7262 {
7264 HOST_WIDE_INT total_bytes;
7278 {
7281 {
7284 }
7287 }
7288 else
7291 }
7294 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7295 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7296 buffer PTR of length LEN bytes. If OFF is not -1 then start
7297 the encoding at byte offset OFF and encode at most LEN bytes.
7298 Return the number of bytes placed in the buffer, or zero upon failure. */
7300 int
7302 {
7303 /* We don't support starting at negative offset and -1 is special. */
7308 {
7329 }
7330 }
7333 /* Subroutine of native_interpret_expr. Interpret the contents of
7334 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7335 If the buffer cannot be interpreted, return NULL_TREE. */
7337 static tree
7339 {
7349 }
7352 /* Subroutine of native_interpret_expr. Interpret the contents of
7353 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7354 If the buffer cannot be interpreted, return NULL_TREE. */
7356 static tree
7358 {
7360 double_int result;
7361 FIXED_VALUE_TYPE fixed_value;
7371 }
7374 /* Subroutine of native_interpret_expr. Interpret the contents of
7375 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7376 If the buffer cannot be interpreted, return NULL_TREE. */
7378 static tree
7380 {
7384 /* There are always 32 bits in each long, no matter the size of
7385 the hosts long. We handle floating point representations with
7386 up to 192 bits. */
7387 REAL_VALUE_TYPE r;
7398 {
7399 /* Both OFFSET and BYTE index within a long;
7400 bitpos indexes the whole float. */
7403 {
7410 else
7412 }
7413 else
7414 {
7417 {
7418 /* Reverse bytes within each long, or within the entire float
7419 if it's smaller than a long (for HFmode). */
7422 }
7423 }
7427 }
7431 }
7434 /* Subroutine of native_interpret_expr. Interpret the contents of
7435 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7436 If the buffer cannot be interpreted, return NULL_TREE. */
7438 static tree
7440 {
7455 }
7458 /* Subroutine of native_interpret_expr. Interpret the contents of
7459 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7460 If the buffer cannot be interpreted, return NULL_TREE. */
7462 static tree
7464 {
7477 {
7482 }
7484 }
7487 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7488 the buffer PTR of length LEN as a constant of type TYPE. For
7489 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7490 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7491 return NULL_TREE. */
7493 tree
7495 {
7497 {
7519 }
7520 }
7522 /* Returns true if we can interpret the contents of a native encoding
7523 as TYPE. */
7525 static bool
7527 {
7529 {
7542 }
7543 }
7545 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7546 TYPE at compile-time. If we're unable to perform the conversion
7547 return NULL_TREE. */
7549 static tree
7551 {
7552 /* We support up to 512-bit values (for V8DFmode). */
7556 /* Check that the host and target are sane. */
7565 }
7567 /* Build an expression for the address of T. Folds away INDIRECT_REF
7568 to avoid confusing the gimplify process. */
7570 tree
7572 {
7573 /* The size of the object is not relevant when talking about its address. */
7578 {
7583 }
7593 {
7598 }
7599 else
7603 }
7605 /* Build an expression for the address of T. */
7607 tree
7609 {
7613 }
7615 /* Fold a unary expression of code CODE and type TYPE with operand
7616 OP0. Return the folded expression if folding is successful.
7617 Otherwise, return NULL_TREE. */
7619 tree
7621 {
7622 tree tem;
7623 tree arg0;
7631 {
7634 {
7635 /* Don't use STRIP_NOPS, because signedness of argument type
7636 matters. */
7638 }
7639 else
7640 {
7641 /* Strip any conversions that don't change the mode. This
7642 is safe for every expression, except for a comparison
7643 expression because its signedness is derived from its
7644 operands.
7646 Note that this is done as an internal manipulation within
7647 the constant folder, in order to find the simplest
7648 representation of the arguments so that their form can be
7649 studied. In any cases, the appropriate type conversions
7650 should be put back in the tree that will get out of the
7651 constant folder. */
7653 }
7656 {
7659 {
7663 }
7664 }
7665 }
7672 {
7679 {
7693 /* If this was a conversion, and all we did was to move into
7694 inside the COND_EXPR, bring it back out. But leave it if
7695 it is a conversion from integer to integer and the
7696 result precision is no wider than a word since such a
7697 conversion is cheap and may be optimized away by combine,
7698 while it couldn't if it were outside the COND_EXPR. Then return
7699 so we don't get into an infinite recursion loop taking the
7700 conversion out and then back in. */
7712 && (INTEGRAL_TYPE_P
7725 }
7726 }
7729 {
7735 CASE_CONVERT:
7739 {
7740 /* If we have (type) (a CMP b) and type is an integral type, return
7741 new expression involving the new type. Canonicalize
7742 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7743 non-integral type.
7744 Do not fold the result as that would not simplify further, also
7745 folding again results in recursions. */
7755 }
7757 /* Handle (T *)&A.B.C for A being of type T and B and C
7758 living at offset zero. This occurs frequently in
7759 C++ upcasting and then accessing the base. */
7763 {
7765 tree offset;
7766 machine_mode mode;
7768 tree base
7772 /* If the reference was to a (constant) zero offset, we can use
7773 the address of the base if it has the same base type
7774 as the result type and the pointer type is unqualified. */
7781 }
7785 /* Detect assigning a bitfield. */
7787 && DECL_BIT_FIELD
7789 {
7790 /* Don't leave an assignment inside a conversion
7791 unless assigning a bitfield. */
7793 /* First do the assignment, then return converted constant. */
7798 }
7800 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7801 constants (if x has signed type, the sign bit cannot be set
7802 in c). This folds extension into the BIT_AND_EXPR.
7803 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7804 very likely don't have maximal range for their precision and this
7805 transformation effectively doesn't preserve non-maximal ranges. */
7809 {
7820 <= HOST_BITS_PER_WIDE_INT
7822 {
7826 cst &= HOST_WIDE_INT_M1U
7830 && !flag_syntax_only
7833 {
7837 }
7838 }
7840 {
7845 }
7846 }
7848 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7849 cast (T1)X will fold away. We assume that this happens when X itself
7850 is a cast. */
7854 {
7858 return fold_build_pointer_plus_loc
7860 }
7862 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7863 of the same precision, and X is an integer type not narrower than
7864 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7870 {
7876 }
7878 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7879 type of X and Y (integer types only). */
7884 {
7885 /* Be careful not to introduce new overflows. */
7886 tree mult_type;
7889 else
7893 {
7900 }
7901 }
7907 {
7912 }
7923 /* Convert fabs((double)float) into (double)fabsf(float). */
7926 {
7932 targ0));
7933 }
7937 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7956 /* Note that the operand of this must be an int
7957 and its values must be 0 or 1.
7958 ("true" is a fixed value perhaps depending on the language,
7959 but we don't handle values other than 1 correctly yet.) */
7966 /* Fold *&X to X if X is an lvalue. */
7968 {
7975 }
7981 }
7984 /* If the operation was a conversion do _not_ mark a resulting constant
7985 with TREE_OVERFLOW if the original constant was not. These conversions
7986 have implementation defined behavior and retaining the TREE_OVERFLOW
7987 flag here would confuse later passes such as VRP. */
7988 tree
7991 {
8000 }
8002 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8003 operands OP0 and OP1. LOC is the location of the resulting expression.
8004 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8005 Return the folded expression if folding is successful. Otherwise,
8006 return NULL_TREE. */
8007 static tree
8010 {
8011 tree tem;
8013 /* We only do these simplifications if we are optimizing. */
8017 /* Check for things like (A || B) && (A || C). We can convert this
8018 to A || (B && C). Note that either operator can be any of the four
8019 truth and/or operations and the transformation will still be
8020 valid. Also note that we only care about order for the
8021 ANDIF and ORIF operators. If B contains side effects, this
8022 might change the truth-value of A. */
8029 {
8049 /* This case if tricky because we must either have commutative
8050 operators or else A10 must not have side-effects. */
8056 a01);
8057 }
8059 /* See if we can build a range comparison. */
8065 {
8069 }
8073 {
8077 }
8079 /* Check for the possibility of merging component references. If our
8080 lhs is another similar operation, try to merge its rhs with our
8081 rhs. Then try to merge our lhs and rhs. */
8095 {
8102 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8103 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8104 We don't want to pack more than two leafs to a non-IF AND/OR
8105 expression.
8106 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8107 equal to IF-CODE, then we don't want to add right-hand operand.
8108 If the inner right-hand side of left-hand operand has
8109 side-effects, or isn't simple, then we can't add to it,
8110 as otherwise we might destroy if-sequence. */
8113 /* Needed for sequence points to handle trappings, and
8114 side-effects. */
8116 {
8118 arg1);
8120 tem);
8121 }
8122 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8123 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8126 /* Needed for sequence points to handle trappings, and
8127 side-effects. */
8129 {
8134 }
8135 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8136 into (A OR B).
8137 For sequence point consistancy, we need to check for trapping,
8138 and side-effects. */
8142 }
8145 }
8147 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8148 by changing CODE to reduce the magnitude of constants involved in
8149 ARG0 of the comparison.
8150 Returns a canonicalized comparison tree if a simplification was
8151 possible, otherwise returns NULL_TREE.
8152 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8153 valid if signed overflow is undefined. */
8155 static tree
8159 {
8164 /* Match A +- CST code arg1. We can change this only if overflow
8165 is undefined. */
8168 /* In principle pointers also have undefined overflow behavior,
8169 but that causes problems elsewhere. */
8176 /* Identify the constant in arg0 and its sign. */
8180 /* Overflowed constants and zero will cause problems. */
8185 /* See if we can reduce the magnitude of the constant in
8186 arg0 by changing the comparison code. */
8187 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8191 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8195 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8199 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8203 else
8207 /* Now build the constant reduced in magnitude. But not if that
8208 would produce one outside of its types range. */
8224 }
8226 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8227 overflow further. Try to decrease the magnitude of constants involved
8228 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8229 and put sole constants at the second argument position.
8230 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8232 static tree
8235 {
8236 tree t;
8241 /* Try canonicalization by simplifying arg0. */
8246 {
8250 }
8252 /* Try canonicalization by simplifying arg1 using the swapped
8253 comparison. */
8261 }
8263 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8264 space. This is used to avoid issuing overflow warnings for
8265 expressions like &p->x which can not wrap. */
8267 static bool
8269 {
8276 wide_int wi_offset;
8282 else
8298 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8299 array. */
8301 {
8302 HOST_WIDE_INT base_size;
8307 }
8310 }
8312 /* Subroutine of fold_binary. This routine performs all of the
8313 transformations that are common to the equality/inequality
8314 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8315 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8316 fold_binary should call fold_binary. Fold a comparison with
8317 tree code CODE and type TYPE with operands OP0 and OP1. Return
8318 the folded comparison or NULL_TREE. */
8320 static tree
8323 {
8333 /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1. */
8335 && (equality_code
8342 {
8343 const enum tree_code
8350 /* If the constant operation overflowed this can be
8351 simplified as a comparison against INT_MAX/INT_MIN. */
8354 {
8358 /* Get the sign of the constant on the lhs if the
8359 operation were VARIABLE + CONST1. */
8363 /* The sign of the constant determines if we overflowed
8364 INT_MAX (const1_sgn == -1) or INT_MIN (const1_sgn == 1).
8365 Canonicalize to the INT_MIN overflow by swapping the comparison
8366 if necessary. */
8370 /* We now can look at the canonicalized case
8371 VARIABLE + 1 CODE2 INT_MIN
8372 and decide on the result. */
8374 {
8378 return
8384 return
8389 }
8390 }
8391 else
8392 {
8395 "when changing X +- C1 cmp C2 to "
8397 WARN_STRICT_OVERFLOW_COMPARISON);
8399 }
8400 }
8402 /* For comparisons of pointers we can decompose it to a compile time
8403 comparison of the base objects and the offsets into the object.
8404 This requires at least one operand being an ADDR_EXPR or a
8405 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8411 {
8414 machine_mode mode;
8418 /* Get base and offset for the access. Strip ADDR_EXPR for
8419 get_inner_reference, but put it back by stripping INDIRECT_REF
8420 off the base object if possible. indirect_baseN will be true
8421 if baseN is not an address but refers to the object itself. */
8424 {
8425 base0
8431 else
8433 }
8435 {
8439 {
8440 base0
8447 else
8449 }
8452 else
8456 {
8462 {
8465 }
8466 }
8467 }
8471 {
8472 base1
8478 else
8480 }
8482 {
8486 {
8487 base1
8494 else
8496 }
8499 else
8503 {
8509 {
8512 }
8513 }
8514 }
8516 /* If we have equivalent bases we might be able to simplify. */
8520 {
8521 /* We can fold this expression to a constant if the non-constant
8522 offset parts are equal. */
8531 {
8537 "occur when comparing P +- C1 with "
8539 WARN_STRICT_OVERFLOW_CONDITIONAL);
8542 {
8556 }
8557 }
8558 /* We can simplify the comparison to a comparison of the variable
8559 offset parts if the constant offset parts are equal.
8560 Be careful to use signed sizetype here because otherwise we
8561 mess with array offsets in the wrong way. This is possible
8562 because pointer arithmetic is restricted to retain within an
8563 object and overflow on pointer differences is undefined as of
8564 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8566 && (equality_code
8569 {
8570 /* By converting to signed sizetype we cover middle-end pointer
8571 arithmetic which operates on unsigned pointer types of size
8572 type size and ARRAY_REF offsets which are properly sign or
8573 zero extended from their type in case it is narrower than
8574 sizetype. */
8577 else
8581 else
8588 "occur when comparing P +- C1 with "
8590 WARN_STRICT_OVERFLOW_COMPARISON);
8593 }
8594 }
8595 /* For equal offsets we can simplify to a comparison of the
8596 base addresses. */
8598 && (indirect_base0
8600 && (indirect_base1
8605 {
8611 }
8612 }
8614 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8615 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8616 the resulting offset is smaller in absolute value than the
8617 original one and has the same sign. */
8626 {
8631 tree cst;
8633 "occur when combining constants around "
8636 /* Put the constant on the side where it doesn't overflow and is
8637 of lower absolute value and of same sign than before. */
8644 {
8647 variable1,
8651 }
8659 {
8665 variable2);
8666 }
8667 }
8673 /* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
8674 constant, we can simplify it. */
8679 {
8683 }
8685 /* If we are comparing an expression that just has comparisons
8686 of two integer values, arithmetic expressions of those comparisons,
8687 and constants, we can simplify it. There are only three cases
8688 to check: the two values can either be equal, the first can be
8689 greater, or the second can be greater. Fold the expression for
8690 those three values. Since each value must be 0 or 1, we have
8691 eight possibilities, each of which corresponds to the constant 0
8692 or 1 or one of the six possible comparisons.
8694 This handles common cases like (a > b) == 0 but also handles
8695 expressions like ((x > y) - (y > x)) > 0, which supposedly
8696 occur in macroized code. */
8699 {
8704 /* Don't handle degenerate cases here; they should already
8705 have been handled anyway. */
8714 {
8718 /* We can't just pass T to eval_subst in case cval1 or cval2
8719 was the same as ARG1. */
8721 tree high_result
8725 arg1);
8726 tree equal_result
8730 arg1);
8731 tree low_result
8735 arg1);
8737 /* All three of these results should be 0 or 1. Confirm they are.
8738 Then use those values to select the proper code to use. */
8743 {
8744 /* Make a 3-bit mask with the high-order bit being the
8745 value for `>', the next for '=', and the low for '<'. */
8749 {
8751 /* Always false. */
8772 /* Always true. */
8774 }
8777 {
8781 }
8783 }
8784 }
8785 }
8787 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8788 into a single range test. */
8796 {
8800 }
8803 }
8806 /* Subroutine of fold_binary. Optimize complex multiplications of the
8807 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8808 argument EXPR represents the expression "z" of type TYPE. */
8810 static tree
8812 {
8817 {
8820 }
8822 {
8825 }
8826 else
8827 {
8831 }
8840 }
8843 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8844 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8846 static bool
8848 {
8852 {
8855 }
8857 {
8863 else
8865 }
8866 else
8872 }
8874 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8875 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8876 NULL_TREE otherwise. */
8878 static tree
8880 {
8897 {
8901 }
8904 {
8910 }
8911 else
8913 }
8915 /* Try to fold a pointer difference of type TYPE two address expressions of
8916 array references AREF0 and AREF1 using location LOC. Return a
8917 simplified expression for the difference or NULL_TREE. */
8919 static tree
8922 {
8927 /* If the bases are array references as well, recurse. If the bases
8928 are pointer indirections compute the difference of the pointers.
8929 If the bases are equal, we are set. */
8932 && (base_offset
8936 && (base_offset
8942 {
8948 base_offset,
8951 }
8953 }
8955 /* If the real or vector real constant CST of type TYPE has an exact
8956 inverse, return it, else return NULL. */
8958 tree
8960 {
8961 REAL_VALUE_TYPE r;
8963 machine_mode mode;
8967 {
8983 {
8988 }
8994 }
8995 }
8997 /* Mask out the tz least significant bits of X of type TYPE where
8998 tz is the number of trailing zeroes in Y. */
8999 static wide_int
9001 {
9006 }
9008 /* Return true when T is an address and is known to be nonzero.
9009 For floating point we further ensure that T is not denormal.
9010 Similar logic is present in nonzero_address in rtlanal.h.
9012 If the return value is based on the assumption that signed overflow
9013 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9014 change *STRICT_OVERFLOW_P. */
9016 static bool
9018 {
9022 /* Doing something useful for floating point would need more work. */
9028 {
9031 strict_overflow_p);
9037 strict_overflow_p);
9045 }
9048 {
9051 strict_overflow_p);
9059 strict_overflow_p);
9074 strict_overflow_p);
9078 strict_overflow_p);
9081 {
9093 }
9097 }
9099 }
9101 /* Return true when T is an address and is known to be nonzero.
9102 Handle warnings about undefined signed overflow. */
9104 static bool
9106 {
9113 "determining that expression is always "
9115 WARN_STRICT_OVERFLOW_MISC);
9117 }
9119 /* Return true if T is known not to be equal to an integer W. */
9121 bool
9123 {
9125 value_range_type rtype;
9127 {
9136 {
9141 }
9146 /* If T has some known zero bits and W has any of those bits set,
9147 then T is known not to be equal to W. */
9155 }
9156 }
9158 /* Fold a binary expression of code CODE and type TYPE with operands
9159 OP0 and OP1. LOC is the location of the resulting expression.
9160 Return the folded expression if folding is successful. Otherwise,
9161 return NULL_TREE. */
9163 tree
9166 {
9181 /* Strip any conversions that don't change the mode. This is
9182 safe for every expression, except for a comparison expression
9183 because its signedness is derived from its operands. So, in
9184 the latter case, only strip conversions that don't change the
9185 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9186 preserved.
9188 Note that this is done as an internal manipulation within the
9189 constant folder, in order to find the simplest representation
9190 of the arguments so that their form can be studied. In any
9191 cases, the appropriate type conversions should be put back in
9192 the tree that will get out of the constant folder. */
9195 {
9198 }
9199 else
9200 {
9203 }
9205 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9206 constant but we can't do arithmetic on them. */
9208 {
9211 {
9215 }
9216 }
9218 /* If this is a commutative operation, and ARG0 is a constant, move it
9219 to ARG1 to reduce the number of tests below. */
9224 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9225 to ARG1 to reduce the number of tests below. */
9234 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9236 First check for cases where an arithmetic operation is applied to a
9237 compound, conditional, or comparison operation. Push the arithmetic
9238 operation inside the compound or conditional to see if any folding
9239 can then be done. Convert comparison to conditional for this purpose.
9240 The also optimizes non-constant cases that used to be done in
9241 expand_expr.
9243 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9244 one of the operands is a comparison and the other is a comparison, a
9245 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9246 code below would make the expression more complex. Change it to a
9247 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9248 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9261 {
9265 boolean_type_node,
9273 }
9277 {
9279 {
9284 tem);
9285 }
9288 {
9293 tem);
9294 }
9299 {
9305 }
9310 {
9316 }
9317 }
9320 {
9322 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9325 {
9331 }
9333 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9336 {
9337 tree base;
9338 HOST_WIDE_INT coffset;
9347 }
9352 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9358 arg1),
9360 arg0)));
9366 {
9367 /* X + (X / CST) * -CST is X % CST. */
9372 {
9381 cst0));
9382 }
9383 }
9385 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9386 one. Make sure the type is not saturating and has the signedness of
9387 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9388 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9395 {
9399 }
9402 {
9403 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9404 (plus (plus (mult) (mult)) (foo)) so that we can
9405 take advantage of the factoring cases below. */
9414 {
9420 else
9433 parg0),
9435 marg)),
9439 return
9445 parg1)));
9446 }
9447 }
9448 else
9449 {
9450 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9451 to __complex__ ( x, y ). This is not the same for SNaNs or
9452 if signed zeros are involved. */
9456 {
9463 {
9467 {
9473 }
9475 {
9481 }
9482 }
9483 }
9491 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9492 We associate floats only if the user has specified
9493 -fassociative-math. */
9497 {
9502 {
9503 tree tree0;
9506 }
9507 }
9508 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9509 We associate floats only if the user has specified
9510 -fassociative-math. */
9514 {
9519 {
9520 tree tree0;
9523 }
9524 }
9525 }
9527 bit_rotate:
9528 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9529 is a rotate of A by C1 bits. */
9530 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9531 is a rotate of A by B bits. */
9532 {
9534 tree rtype;
9543 /* Only create rotates in complete modes. Other cases are not
9544 expanded properly. */
9547 {
9561 {
9565 code0 == LSHIFT_EXPR
9569 }
9571 {
9579 element_precision
9583 return
9586 ? LROTATE_EXPR
9591 }
9593 {
9601 element_precision
9605 return fold_convert_loc
9608 ? LROTATE_EXPR
9612 }
9613 }
9614 }
9616 associate:
9617 /* In most languages, can't associate operations on floats through
9618 parentheses. Rather than remember where the parentheses were, we
9619 don't associate floats at all, unless the user has specified
9620 -fassociative-math.
9621 And, we need to make sure type is not saturating. */
9625 {
9631 /* Split both trees into variables, constants, and literals. Then
9632 associate each group together, the constants with literals,
9633 then the result with variables. This increases the chances of
9634 literals being recombined later and of generating relocatable
9635 expressions for the sum of a constant and literal. */
9641 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9645 /* With undefined overflow prefer doing association in a type
9646 which wraps on overflow, if that is one of the operand types. */
9649 {
9657 }
9659 /* With undefined overflow we can only associate constants with one
9660 variable, and constants whose association doesn't overflow. */
9663 {
9665 {
9671 {
9674 }
9681 {
9684 }
9690 /* The only case we can still associate with two variables
9691 is if they cancel out. */
9695 }
9696 }
9698 /* Only do something if we found more than two objects. Otherwise,
9699 nothing has changed and we risk infinite recursion. */
9705 {
9717 /* Preserve the MINUS_EXPR if the negative part of the literal is
9718 greater than the positive part. Otherwise, the multiplicative
9719 folding code (i.e extract_muldiv) may be fooled in case
9720 unsigned constants are subtracted, like in the following
9721 example: ((X*2 + 4) - 8U)/2. */
9723 {
9727 {
9731 }
9732 else
9733 {
9737 }
9738 }
9740 /* Don't introduce overflows through reassociation. */
9747 {
9749 return
9753 else
9754 {
9757 return
9761 }
9762 }
9765 return
9768 }
9769 }
9774 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9783 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9784 __complex__ ( x, -y ). This is not the same for SNaNs or if
9785 signed zeros are involved. */
9789 {
9796 {
9800 {
9802 arg1r ? arg1r
9807 }
9809 {
9813 arg1i ? arg1i
9816 }
9817 }
9818 }
9820 /* A - B -> A + (-B) if B is easily negatable. */
9824 /* Avoid this transformation if B is a positive REAL_CST. */
9832 /* Fold &a[i] - &a[j] to i-j. */
9837 {
9843 }
9846 && flag_unsafe_math_optimizations
9852 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9853 one. Make sure the type is not saturating and has the signedness of
9854 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9855 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9862 {
9866 }
9872 {
9873 /* Transform x * -C into -x * C if x is easily negatable. */
9883 /* (A + A) * C -> A * 2 * C */
9895 /* ((T) (X /[ex] C)) * C cancels out if the conversion is
9896 sign-changing only. */
9906 {
9909 "occur when simplifying "
9911 WARN_STRICT_OVERFLOW_MISC);
9913 }
9915 /* Optimize z * conj(z) for integer complex numbers. */
9922 }
9923 else
9924 {
9925 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9926 This is not the same for NaNs or if signed zeros are
9927 involved. */
9933 {
9936 return
9942 return
9947 }
9949 /* Optimize z * conj(z) for floating point complex numbers.
9950 Guarded by flag_unsafe_math_optimizations as non-finite
9951 imaginary components don't produce scalar results. */
9962 {
9964 /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x. */
9966 && optimize
9968 {
9972 {
9975 }
9976 }
9977 }
9978 }
9982 /* Canonicalize (X & C1) | C2. */
9986 {
9991 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9999 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10004 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10005 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10006 mode which allows further optimizations. */
10011 {
10015 {
10018 }
10019 }
10026 c3)),
10027 arg1);
10028 }
10030 /* See if this can be simplified into a rotate first. If that
10031 is unsuccessful continue in the association code. */
10035 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10043 /* See if this can be simplified into a rotate first. If that
10044 is unsuccessful continue in the association code. */
10048 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10053 {
10054 tree tem2;
10061 }
10062 /* Fold ~X & 1 as (X & 1) == 0. */
10066 {
10067 tree tem2;
10074 }
10075 /* Fold !X & 1 as X == 0. */
10078 {
10082 }
10084 /* Fold (X ^ Y) & Y as ~X & Y. */
10087 {
10092 }
10093 /* Fold (X ^ Y) & X as ~Y & X. */
10097 {
10102 }
10103 /* Fold X & (X ^ Y) as X & ~Y. */
10106 {
10111 }
10112 /* Fold X & (Y ^ X) as ~Y & X. */
10116 {
10121 }
10123 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10124 multiple of 1 << CST. */
10126 {
10133 }
10135 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10136 bits from CST2. */
10140 {
10148 {
10149 /* Avoid the transform if arg1 is a mask of some
10150 mode which allows further optimizations. */
10157 }
10158 }
10160 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10161 ((A & N) + B) & M -> (A + B) & M
10162 Similarly if (N & M) == 0,
10163 ((A | N) + B) & M -> (A + B) & M
10164 and for - instead of + (or unary - instead of +)
10165 and/or ^ instead of |.
10166 If B is constant and (B & M) == 0, fold into A & M. */
10168 {
10177 {
10180 wide_int cst0;
10182 /* Now we know that arg0 is (C + D) or (C - D) or
10183 -C and arg1 (M) is == (1LL << cst) - 1.
10184 Store C into PMOP[0] and D into PMOP[1]. */
10188 {
10191 }
10198 {
10208 {
10211 }
10214 /* If C or D is of the form (A & N) where
10215 (N & M) == M, or of the form (A | N) or
10216 (A ^ N) where (N & M) == 0, replace it with A. */
10220 /* If C or D is a N where (N & M) == 0, it can be
10221 omitted (assumed 0). */
10229 }
10231 /* Only build anything new if we optimized one or both arguments
10232 above. */
10236 {
10239 {
10240 /* Perform the operations in a type that has defined
10241 overflow behavior. */
10247 }
10252 {
10260 else
10262 }
10265 else
10268 /* TEM is now the new binary +, - or unary - replacement. */
10272 }
10273 }
10274 }
10276 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10279 {
10284 return
10286 }
10291 /* Don't touch a floating-point divide by zero unless the mode
10292 of the constant can represent infinity. */
10298 /* (-A) / (-B) -> A / B */
10310 /* Fall through */
10313 /* Simplify A / (B << N) where A and B are positive and B is
10314 a power of 2, to A >> (N + log2(B)). */
10319 {
10322 {
10330 WARN_STRICT_OVERFLOW_MISC);
10336 }
10337 }
10339 /* Fall through */
10347 /* Convert -A / -B to A / B when the type is signed and overflow is
10348 undefined. */
10352 {
10355 "when distributing negation across "
10357 WARN_STRICT_OVERFLOW_MISC);
10362 }
10366 {
10369 "when distributing negation across "
10371 WARN_STRICT_OVERFLOW_MISC);
10376 }
10378 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10379 operation, EXACT_DIV_EXPR.
10381 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10382 At one time others generated faster code, it's not clear if they do
10383 after the last round to changes to the DIV code in expmed.c. */
10394 {
10398 WARN_STRICT_OVERFLOW_MISC);
10400 }
10412 {
10416 WARN_STRICT_OVERFLOW_MISC);
10418 }
10426 /* Since negative shift count is not well-defined,
10427 don't try to compute it in the compiler. */
10433 /* If we have a rotate of a bit operation with the rotate count and
10434 the second operand of the bit operation both constant,
10435 permute the two operations. */
10447 /* Two consecutive rotates adding up to the some integer
10448 multiple of the precision of the type can be ignored. */
10463 /* Note that the operands of this must be ints
10464 and their values must be 0 or 1.
10465 ("true" is a fixed value perhaps depending on the language.) */
10466 /* If first arg is constant zero, return it. */
10470 /* If either arg is constant true, drop it. */
10474 /* Preserve sequence points. */
10477 /* If second arg is constant zero, result is zero, but first arg
10478 must be evaluated. */
10481 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10482 case will be handled here. */
10486 /* !X && X is always false. */
10490 /* X && !X is always false. */
10495 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10496 means A >= Y && A != MAX, but in this case we know that
10497 A < X <= MAX. */
10501 {
10509 }
10518 /* Note that the operands of this must be ints
10519 and their values must be 0 or true.
10520 ("true" is a fixed value perhaps depending on the language.) */
10521 /* If first arg is constant true, return it. */
10525 /* If either arg is constant zero, drop it. */
10529 /* Preserve sequence points. */
10532 /* If second arg is constant true, result is true, but we must
10533 evaluate first arg. */
10536 /* Likewise for first arg, but note this only occurs here for
10537 TRUTH_OR_EXPR. */
10541 /* !X || X is always true. */
10545 /* X || !X is always true. */
10550 /* (X && !Y) || (!X && Y) is X ^ Y */
10553 {
10570 }
10579 /* If the second arg is constant zero, drop it. */
10582 /* If the second arg is constant true, this is a logical inversion. */
10584 {
10587 }
10588 /* Identical arguments cancel to zero. */
10592 /* !X ^ X is always true. */
10597 /* X ^ !X is always true. */
10613 /* bool_var != 1 becomes !bool_var. */
10620 /* bool_var == 0 becomes !bool_var. */
10627 /* !exp != 0 becomes !exp */
10632 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10641 {
10647 }
10649 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10658 {
10664 }
10666 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
10674 code == NE_EXPR
10678 /* Transform comparisons of the form X CMP C - X if C % 2 == 1. */
10686 code == NE_EXPR
10690 /* If this is an EQ or NE comparison with zero and ARG0 is
10691 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10692 two operations, but the latter can be done in one less insn
10693 on machines that have only two-operand insns or on which a
10694 constant cannot be the first operand. */
10697 {
10702 {
10709 arg1);
10710 }
10713 {
10720 arg1);
10721 }
10722 }
10724 /* If this is an NE or EQ comparison of zero against the result of a
10725 signed MOD operation whose second operand is a power of 2, make
10726 the MOD operation unsigned since it is simpler and equivalent. */
10734 {
10744 }
10746 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10747 C1 is a valid shift constant, and C2 is a power of two, i.e.
10748 a single bit. */
10752 == INTEGER_CST
10755 {
10760 /* Check for a valid shift count. */
10762 {
10766 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10767 can be rewritten as (X & (C2 << C1)) != 0. */
10769 {
10774 }
10775 /* Otherwise, for signed (arithmetic) shifts,
10776 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10777 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10781 /* Otherwise, of unsigned (logical) shifts,
10782 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10783 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10784 else
10788 arg000);
10789 }
10790 }
10792 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
10793 Similarly for NE_EXPR. */
10797 {
10801 tree dandnotc
10804 notc);
10808 }
10810 /* If this is a comparison of a field, we may be able to simplify it. */
10813 /* Handle the constant case even without -O
10814 to make sure the warnings are given. */
10816 {
10820 }
10822 /* Optimize comparisons of strlen vs zero to a compare of the
10823 first character of the string vs zero. To wit,
10824 strlen(ptr) == 0 => *ptr == 0
10825 strlen(ptr) != 0 => *ptr != 0
10826 Other cases should reduce to one of these two (or a constant)
10827 due to the return value of strlen being unsigned. */
10830 {
10838 {
10843 }
10844 }
10846 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10847 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10851 {
10856 {
10858 {
10861 }
10864 }
10865 }
10867 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10868 (X & C) == 0 when C is a single bit. */
10873 {
10880 arg1));
10881 }
10883 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10884 constant C is a power of two, i.e. a single bit. */
10891 {
10895 }
10897 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10898 when is C is a power of two, i.e. a single bit. */
10905 {
10911 }
10915 {
10918 }
10920 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10923 {
10936 arg01),
10945 arg01),
10954 arg00),
10963 arg00),
10965 }
10969 {
10976 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10977 operand_equal_p guarantees no side-effects so we don't need
10978 to use omit_one_operand on Z. */
10982 arg10));
10986 arg11));
10990 arg10));
10994 arg11));
10996 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10999 {
11005 }
11006 }
11008 /* Attempt to simplify equality/inequality comparisons of complex
11009 values. Only lower the comparison if the result is known or
11010 can be simplified to a single scalar comparison. */
11015 {
11020 {
11023 }
11024 else
11025 {
11028 }
11031 {
11034 }
11035 else
11036 {
11039 }
11043 {
11045 {
11050 }
11051 else
11052 {
11057 }
11058 }
11062 {
11064 {
11069 }
11070 else
11071 {
11076 }
11077 }
11078 }
11090 /* Transform comparisons of the form X +- C CMP X. */
11097 {
11104 else
11107 /* (X - c) > X becomes false. */
11111 {
11115 "occur when assuming that (X - c) > X "
11117 WARN_STRICT_OVERFLOW_ALL);
11119 }
11121 /* Likewise (X + c) < X becomes false. */
11125 {
11129 "occur when assuming that "
11131 WARN_STRICT_OVERFLOW_ALL);
11133 }
11135 /* Convert (X - c) <= X to true. */
11140 {
11144 "occur when assuming that "
11146 WARN_STRICT_OVERFLOW_ALL);
11148 }
11150 /* Convert (X + c) >= X to true. */
11155 {
11159 "occur when assuming that "
11161 WARN_STRICT_OVERFLOW_ALL);
11163 }
11166 {
11167 /* Convert X + c > X and X - c < X to true for integers. */
11171 {
11174 "not occur when assuming that "
11176 WARN_STRICT_OVERFLOW_ALL);
11178 }
11183 {
11186 "not occur when assuming that "
11188 WARN_STRICT_OVERFLOW_ALL);
11190 }
11192 /* Convert X + c <= X and X - c >= X to false for integers. */
11196 {
11199 "not occur when assuming that "
11201 WARN_STRICT_OVERFLOW_ALL);
11203 }
11208 {
11211 "not occur when assuming that "
11213 WARN_STRICT_OVERFLOW_ALL);
11215 }
11216 }
11217 }
11219 /* If we are comparing an ABS_EXPR with a constant, we can
11220 convert all the cases into explicit comparisons, but they may
11221 well not be faster than doing the ABS and one comparison.
11222 But ABS (X) <= C is a range comparison, which becomes a subtraction
11223 and a comparison, and is probably faster. */
11237 /* Convert ABS_EXPR<x> >= 0 to true. */
11244 {
11247 "when simplifying comparison of "
11249 WARN_STRICT_OVERFLOW_CONDITIONAL);
11252 arg0);
11253 }
11255 /* Convert ABS_EXPR<x> < 0 to false. */
11260 {
11263 "when simplifying comparison of "
11265 WARN_STRICT_OVERFLOW_CONDITIONAL);
11268 arg0);
11269 }
11271 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11272 and similarly for >= into !=. */
11282 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11283 otherwise Y might be >= # of bits in X's type and thus e.g.
11284 (unsigned char) (1 << Y) for Y 15 might be 0.
11285 If the cast is widening, then 1 << Y should have unsigned type,
11286 otherwise if Y is number of bits in the signed shift type minus 1,
11287 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11288 31 might be 0xffffffff80000000. */
11299 {
11305 }
11317 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11318 {
11330 }
11335 /* When pedantic, a compound expression can be neither an lvalue
11336 nor an integer constant expression. */
11339 /* Don't let (0, 0) be null pointer constant. */
11345 /* An ASSERT_EXPR should never be passed to fold_binary. */
11351 }
11353 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11354 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11355 of GOTO_EXPR. */
11357 static tree
11359 {
11361 {
11368 /* ... fall through ... */
11372 }
11373 }
11375 /* Return whether the sub-tree ST contains a label which is accessible from
11376 outside the sub-tree. */
11378 static bool
11380 {
11381 return
11383 }
11385 /* Fold a ternary expression of code CODE and type TYPE with operands
11386 OP0, OP1, and OP2. Return the folded expression if folding is
11387 successful. Otherwise, return NULL_TREE. */
11389 tree
11392 {
11393 tree tem;
11400 /* If this is a commutative operation, and OP0 is a constant, move it
11401 to OP1 to reduce the number of tests below. */
11410 /* Strip any conversions that don't change the mode. This is safe
11411 for every expression, except for a comparison expression because
11412 its signedness is derived from its operands. So, in the latter
11413 case, only strip conversions that don't change the signedness.
11415 Note that this is done as an internal manipulation within the
11416 constant folder, in order to find the simplest representation of
11417 the arguments so that their form can be studied. In any cases,
11418 the appropriate type conversions should be put back in the tree
11419 that will get out of the constant folder. */
11421 {
11424 }
11427 {
11430 }
11433 {
11436 }
11439 {
11443 {
11449 }
11454 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11455 so all simple results must be passed through pedantic_non_lvalue. */
11457 {
11460 /* Only optimize constant conditions when the selected branch
11461 has the same type as the COND_EXPR. This avoids optimizing
11462 away "c ? x : throw", where the throw has a void type.
11463 Avoid throwing away that operand which contains label. */
11470 }
11472 {
11477 {
11482 {
11490 }
11494 }
11495 }
11497 /* If we have A op B ? A : C, we may be able to convert this to a
11498 simpler expression, depending on the operation and the values
11499 of B and C. Signed zeros prevent all of these transformations,
11500 for reasons given above each one.
11502 Also try swapping the arguments and inverting the conditional. */
11507 {
11511 }
11515 op2,
11518 {
11522 {
11526 }
11527 }
11529 /* If the second operand is simpler than the third, swap them
11530 since that produces better jump optimization results. */
11533 {
11535 /* See if this can be inverted. If it can't, possibly because
11536 it was a floating-point inequality comparison, don't do
11537 anything. */
11541 }
11543 /* Convert A ? 1 : 0 to simply A. */
11548 /* If we try to convert OP0 to our type, the
11549 call to fold will try to move the conversion inside
11550 a COND, which will recurse. In that case, the COND_EXPR
11551 is probably the best choice, so leave it alone. */
11555 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11556 over COND_EXPR in cases such as floating point comparisons. */
11565 arg0)));
11567 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11572 {
11573 /* sign_bit_p looks through both zero and sign extensions,
11574 but for this optimization only sign extensions are
11575 usable. */
11578 {
11581 {
11584 }
11586 }
11587 /* sign_bit_p only checks ARG1 bits within A's precision.
11588 If <sign bit of A> has wider type than A, bits outside
11589 of A's precision in <sign bit of A> need to be checked.
11590 If they are all 0, this optimization needs to be done
11591 in unsigned A's type, if they are all 1 in signed A's type,
11592 otherwise this can't be done. */
11598 {
11600 tree tem_type;
11613 {
11616 }
11618 {
11621 }
11622 else
11624 }
11627 return
11633 arg1)));
11634 }
11636 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11637 already handled above. */
11642 {
11651 }
11653 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11654 is probably obsolete because the first operand should be a
11655 truth value (that's why we have the two cases above), but let's
11656 leave it in until we can confirm this for all front-ends. */
11668 /* Disable the transformations below for vectors, since
11669 fold_binary_op_with_conditional_arg may undo them immediately,
11670 yielding an infinite loop. */
11674 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11683 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11688 {
11690 /* Only perform transformation if ARG0 is easily inverted. */
11694 ? BIT_IOR_EXPR
11697 arg1);
11698 }
11700 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11705 {
11707 /* Only perform transformation if ARG0 is easily inverted. */
11713 op2);
11714 }
11716 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11728 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11729 of fold_ternary on them. */
11739 {
11749 {
11754 {
11762 }
11764 /* Constructor elements can be subvectors. */
11767 {
11771 }
11773 /* We keep an exact subset of the constructor elements. */
11775 {
11781 {
11785 }
11793 CONSTRUCTOR_ELT
11796 }
11797 /* The bitfield references a single constructor element. */
11799 {
11804 else
11808 }
11809 }
11810 }
11812 /* A bit-field-ref that referenced the full argument can be stripped. */
11818 /* On constants we can use native encode/interpret to constant
11819 fold (nearly) all BIT_FIELD_REFs. */
11823 /* This limitation should not be necessary, we just need to
11824 round this up to mode size. */
11826 /* Need bit-shifting of the buffer to relax the following. */
11828 {
11833 /* ??? We cannot tell native_encode_expr to start at
11834 some random byte only. So limit us to a reasonable amount
11835 of work. */
11837 {
11842 {
11848 }
11849 }
11850 }
11855 /* For integers we can decompose the FMA if possible. */
11867 {
11883 {
11888 /* Make sure that the perm value is in an acceptable
11889 range. */
11898 else
11903 }
11906 {
11911 }
11916 {
11921 }
11927 {
11931 }
11936 /* Some targets are deficient and fail to expand a single
11937 argument permutation while still allowing an equivalent
11938 2-argument version. */
11942 {
11945 }
11948 {
11955 }
11959 }
11965 }
11967 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11968 of an array (or vector). */
11970 tree
11972 {
11977 {
11980 {
11981 /* Static constructors for variably sized objects makes no sense. */
11985 }
11986 }
11997 offset_int max_index;
12002 {
12003 /* Array constructor might explicitly set index, or specify a range,
12004 or leave index NULL meaning that it is next index after previous
12005 one. */
12007 {
12010 else
12011 {
12015 }
12016 }
12017 else
12018 {
12024 }
12026 /* Do we have match? */
12030 }
12032 }
12034 /* Perform constant folding and related simplification of EXPR.
12035 The related simplifications include x*1 => x, x*0 => 0, etc.,
12036 and application of the associative law.
12037 NOP_EXPR conversions may be removed freely (as long as we
12038 are careful not to change the type of the overall expression).
12039 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
12040 but we can constant-fold them if they have constant operands. */
12042 #ifdef ENABLE_FOLD_CHECKING
12043 # define fold(x) fold_1 (x)
12045 static
12046 #endif
12047 tree
12049 {
12053 tree tem;
12056 /* Return right away if a constant. */
12060 /* CALL_EXPR-like objects with variable numbers of operands are
12061 treated specially. */
12063 {
12065 {
12068 }
12070 }
12073 {
12078 {
12096 }
12097 }
12100 {
12102 {
12109 {
12114 }
12117 }
12119 /* Return a VECTOR_CST if possible. */
12121 {
12127 tree val;
12133 }
12141 }
12143 #ifdef ENABLE_FOLD_CHECKING
12144 #undef fold
12151 /* When --enable-checking=fold, compute a digest of expr before
12152 and after actual fold call to see if fold did not accidentally
12153 change original expr. */
12155 tree
12157 {
12158 tree ret;
12178 }
12180 void
12182 {
12193 }
12195 static void
12197 {
12199 }
12201 static void
12204 {
12210 recursive_label:
12220 {
12221 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12226 }
12233 {
12234 /* Allow these fields to be modified. */
12235 tree tmp;
12243 {
12246 }
12247 }
12258 {
12261 {
12276 }
12280 {
12293 }
12310 {
12316 }
12319 {
12321 {
12324 }
12326 }
12337 {
12340 }
12350 }
12351 }
12353 /* Helper function for outputting the checksum of a tree T. When
12354 debugging with gdb, you can "define mynext" to be "next" followed
12355 by "call debug_fold_checksum (op0)", then just trace down till the
12356 outputs differ. */
12358 DEBUG_FUNCTION void
12360 {
12375 }
12377 #endif
12379 /* Fold a unary tree expression with code CODE of type TYPE with an
12380 operand OP0. LOC is the location of the resulting expression.
12381 Return a folded expression if successful. Otherwise, return a tree
12382 expression with code CODE of type TYPE with an operand OP0. */
12384 tree
12387 {
12388 tree tem;
12389 #ifdef ENABLE_FOLD_CHECKING
12398 #endif
12404 #ifdef ENABLE_FOLD_CHECKING
12411 #endif
12413 }
12415 /* Fold a binary tree expression with code CODE of type TYPE with
12416 operands OP0 and OP1. LOC is the location of the resulting
12417 expression. Return a folded expression if successful. Otherwise,
12418 return a tree expression with code CODE of type TYPE with operands
12419 OP0 and OP1. */
12421 tree
12424 MEM_STAT_DECL)
12425 {
12426 tree tem;
12427 #ifdef ENABLE_FOLD_CHECKING
12444 #endif
12450 #ifdef ENABLE_FOLD_CHECKING
12465 #endif
12467 }
12469 /* Fold a ternary tree expression with code CODE of type TYPE with
12470 operands OP0, OP1, and OP2. Return a folded expression if
12471 successful. Otherwise, return a tree expression with code CODE of
12472 type TYPE with operands OP0, OP1, and OP2. */
12474 tree
12477 {
12478 tree tem;
12479 #ifdef ENABLE_FOLD_CHECKING
12503 #endif
12510 #ifdef ENABLE_FOLD_CHECKING
12533 #endif
12535 }
12537 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12538 arguments in ARGARRAY, and a null static chain.
12539 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12540 of type TYPE from the given operands as constructed by build_call_array. */
12542 tree
12545 {
12546 tree tem;
12547 #ifdef ENABLE_FOLD_CHECKING
12566 #endif
12572 #ifdef ENABLE_FOLD_CHECKING
12588 #endif
12590 }
12592 /* Perform constant folding and related simplification of initializer
12593 expression EXPR. These behave identically to "fold_buildN" but ignore
12594 potential run-time traps and exceptions that fold must preserve. */
12596 #define START_FOLD_INIT \
12597 int saved_signaling_nans = flag_signaling_nans;\
12598 int saved_trapping_math = flag_trapping_math;\
12599 int saved_rounding_math = flag_rounding_math;\
12600 int saved_trapv = flag_trapv;\
12601 int saved_folding_initializer = folding_initializer;\
12602 flag_signaling_nans = 0;\
12603 flag_trapping_math = 0;\
12604 flag_rounding_math = 0;\
12605 flag_trapv = 0;\
12606 folding_initializer = 1;
12608 #define END_FOLD_INIT \
12609 flag_signaling_nans = saved_signaling_nans;\
12610 flag_trapping_math = saved_trapping_math;\
12611 flag_rounding_math = saved_rounding_math;\
12612 flag_trapv = saved_trapv;\
12613 folding_initializer = saved_folding_initializer;
12615 tree
12618 {
12619 tree result;
12620 START_FOLD_INIT;
12624 END_FOLD_INIT;
12626 }
12628 tree
12631 {
12632 tree result;
12633 START_FOLD_INIT;
12637 END_FOLD_INIT;
12639 }
12641 tree
12644 {
12645 tree result;
12646 START_FOLD_INIT;
12650 END_FOLD_INIT;
12652 }
12654 #undef START_FOLD_INIT
12655 #undef END_FOLD_INIT
12657 /* Determine if first argument is a multiple of second argument. Return 0 if
12658 it is not, or we cannot easily determined it to be.
12660 An example of the sort of thing we care about (at this point; this routine
12661 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12662 fold cases do now) is discovering that
12664 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12666 is a multiple of
12668 SAVE_EXPR (J * 8)
12670 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12672 This code also handles discovering that
12674 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12676 is a multiple of 8 so we don't have to worry about dealing with a
12677 possible remainder.
12679 Note that we *look* inside a SAVE_EXPR only to determine how it was
12680 calculated; it is not safe for fold to do much of anything else with the
12681 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12682 at run time. For example, the latter example above *cannot* be implemented
12683 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12684 evaluation time of the original SAVE_EXPR is not necessarily the same at
12685 the time the new expression is evaluated. The only optimization of this
12686 sort that would be valid is changing
12688 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12690 divided by 8 to
12692 SAVE_EXPR (I) * SAVE_EXPR (J)
12694 (where the same SAVE_EXPR (J) is used in the original and the
12695 transformed version). */
12697 int
12699 {
12707 {
12709 /* Bitwise and provides a power of two multiple. If the mask is
12710 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12713 /* FALLTHRU */
12726 {
12730 /* const_binop may not detect overflow correctly,
12731 so check for it explicitly here. */
12735 size_one_node,
12736 op1)))
12739 }
12743 /* Can't handle conversions from non-integral or wider integral type. */
12749 /* .. fall through ... */
12766 SIGNED);
12770 }
12771 }
12773 #define tree_expr_nonnegative_warnv_p(X, Y) \
12776 #define RECURSE(X) \
12777 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12779 /* Return true if CODE or TYPE is known to be non-negative. */
12781 static bool
12783 {
12786 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12787 have a signed:1 type (where the value is -1 and 0). */
12790 }
12792 /* Return true if (CODE OP0) is known to be non-negative. If the return
12793 value is based on the assumption that signed overflow is undefined,
12794 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12795 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12797 bool
12800 {
12805 {
12807 /* We can't return 1 if flag_wrapv is set because
12808 ABS_EXPR<INT_MIN> = INT_MIN. */
12812 {
12815 }
12823 CASE_CONVERT:
12824 {
12829 {
12833 {
12837 }
12838 }
12840 {
12846 }
12847 }
12852 }
12854 /* We don't know sign of `t', so be conservative and return false. */
12856 }
12858 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12859 value is based on the assumption that signed overflow is undefined,
12860 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12861 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12863 bool
12867 {
12872 {
12878 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12879 both unsigned and at least 2 bits shorter than the result. */
12883 {
12888 {
12892 }
12893 }
12898 {
12899 /* x * x is always non-negative for floating point x
12900 or without overflow. */
12903 {
12908 }
12909 }
12911 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12912 both unsigned and their total bits is shorter than the result. */
12916 {
12935 {
12945 }
12946 }
12973 }
12975 /* We don't know sign of `t', so be conservative and return false. */
12977 }
12979 /* Return true if T is known to be non-negative. If the return
12980 value is based on the assumption that signed overflow is undefined,
12981 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12982 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12984 bool
12986 {
12991 {
13005 /* Limit the depth of recursion to avoid quadratic behavior.
13006 This is expected to catch almost all occurrences in practice.
13007 If this code misses important cases that unbounded recursion
13008 would not, passes that need this information could be revised
13009 to provide it through dataflow propagation. */
13017 }
13018 }
13020 /* Return true if T is known to be non-negative. If the return
13021 value is based on the assumption that signed overflow is undefined,
13022 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13023 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13025 bool
13028 {
13030 {
13031 CASE_CFN_ACOS:
13032 CASE_CFN_ACOSH:
13033 CASE_CFN_CABS:
13034 CASE_CFN_COSH:
13035 CASE_CFN_ERFC:
13036 CASE_CFN_EXP:
13037 CASE_CFN_EXP10:
13038 CASE_CFN_EXP2:
13039 CASE_CFN_FABS:
13040 CASE_CFN_FDIM:
13041 CASE_CFN_HYPOT:
13042 CASE_CFN_POW10:
13043 CASE_CFN_FFS:
13044 CASE_CFN_PARITY:
13045 CASE_CFN_POPCOUNT:
13046 CASE_CFN_CLZ:
13047 CASE_CFN_CLRSB:
13050 /* Always true. */
13053 CASE_CFN_SQRT:
13054 /* sqrt(-0.0) is -0.0. */
13059 CASE_CFN_ASINH:
13060 CASE_CFN_ATAN:
13061 CASE_CFN_ATANH:
13062 CASE_CFN_CBRT:
13063 CASE_CFN_CEIL:
13064 CASE_CFN_ERF:
13065 CASE_CFN_EXPM1:
13066 CASE_CFN_FLOOR:
13067 CASE_CFN_FMOD:
13068 CASE_CFN_FREXP:
13069 CASE_CFN_ICEIL:
13070 CASE_CFN_IFLOOR:
13071 CASE_CFN_IRINT:
13072 CASE_CFN_IROUND:
13073 CASE_CFN_LCEIL:
13074 CASE_CFN_LDEXP:
13075 CASE_CFN_LFLOOR:
13076 CASE_CFN_LLCEIL:
13077 CASE_CFN_LLFLOOR:
13078 CASE_CFN_LLRINT:
13079 CASE_CFN_LLROUND:
13080 CASE_CFN_LRINT:
13081 CASE_CFN_LROUND:
13082 CASE_CFN_MODF:
13083 CASE_CFN_NEARBYINT:
13084 CASE_CFN_RINT:
13085 CASE_CFN_ROUND:
13086 CASE_CFN_SCALB:
13087 CASE_CFN_SCALBLN:
13088 CASE_CFN_SCALBN:
13089 CASE_CFN_SIGNBIT:
13090 CASE_CFN_SIGNIFICAND:
13091 CASE_CFN_SINH:
13092 CASE_CFN_TANH:
13093 CASE_CFN_TRUNC:
13094 /* True if the 1st argument is nonnegative. */
13097 CASE_CFN_FMAX:
13098 /* True if the 1st OR 2nd arguments are nonnegative. */
13101 CASE_CFN_FMIN:
13102 /* True if the 1st AND 2nd arguments are nonnegative. */
13105 CASE_CFN_COPYSIGN:
13106 /* True if the 2nd argument is nonnegative. */
13109 CASE_CFN_POWI:
13110 /* True if the 1st argument is nonnegative or the second
13111 argument is an even integer. */
13117 CASE_CFN_POW:
13118 /* True if the 1st argument is nonnegative or the second
13119 argument is an even integer valued real. */
13121 {
13122 REAL_VALUE_TYPE c;
13123 HOST_WIDE_INT n;
13128 {
13129 REAL_VALUE_TYPE cint;
13133 }
13134 }
13139 }
13141 }
13143 /* Return true if T is known to be non-negative. If the return
13144 value is based on the assumption that signed overflow is undefined,
13145 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13146 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13148 static bool
13150 {
13156 {
13158 {
13162 /* If the initializer is non-void, then it's a normal expression
13163 that will be assigned to the slot. */
13167 /* Otherwise, the initializer sets the slot in some way. One common
13168 way is an assignment statement at the end of the initializer. */
13170 {
13178 else
13180 }
13186 }
13189 {
13195 arg0,
13196 arg1,
13198 }
13211 }
13212 }
13214 #undef RECURSE
13215 #undef tree_expr_nonnegative_warnv_p
13217 /* Return true if T is known to be non-negative. If the return
13218 value is based on the assumption that signed overflow is undefined,
13219 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13220 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13222 bool
13224 {
13231 {
13253 }
13256 {
13282 }
13283 }
13285 /* Return true if `t' is known to be non-negative. Handle warnings
13286 about undefined signed overflow. */
13288 bool
13290 {
13297 "determining that expression is always "
13299 WARN_STRICT_OVERFLOW_MISC);
13301 }
13304 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13305 For floating point we further ensure that T is not denormal.
13306 Similar logic is present in nonzero_address in rtlanal.h.
13308 If the return value is based on the assumption that signed overflow
13309 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13310 change *STRICT_OVERFLOW_P. */
13312 bool
13315 {
13317 {
13320 strict_overflow_p);
13323 {
13329 strict_overflow_p));
13330 }
13335 strict_overflow_p);
13339 }
13342 }
13344 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13345 For floating point we further ensure that T is not denormal.
13346 Similar logic is present in nonzero_address in rtlanal.h.
13348 If the return value is based on the assumption that signed overflow
13349 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13350 change *STRICT_OVERFLOW_P. */
13352 bool
13354 tree type,
13355 tree op0,
13357 {
13360 {
13364 {
13365 /* With the presence of negative values it is hard
13366 to say something. */
13373 /* One of operands must be positive and the other non-negative. */
13374 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13375 overflows, on a twos-complement machine the sum of two
13376 nonnegative numbers can never be zero. */
13378 strict_overflow_p)
13380 strict_overflow_p));
13381 }
13386 {
13388 strict_overflow_p)
13390 strict_overflow_p))
13391 {
13394 }
13395 }
13404 {
13407 }
13414 {
13418 /* When both operands are nonzero, then MAX must be too. */
13420 strict_overflow_p))
13423 /* MAX where operand 0 is positive is positive. */
13425 strict_overflow_p);
13426 }
13427 /* MAX where operand 1 is positive is positive. */
13432 {
13436 }
13441 strict_overflow_p)
13443 strict_overflow_p));
13447 }
13450 }
13452 /* Return true when T is an address and is known to be nonzero.
13453 For floating point we further ensure that T is not denormal.
13454 Similar logic is present in nonzero_address in rtlanal.h.
13456 If the return value is based on the assumption that signed overflow
13457 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13458 change *STRICT_OVERFLOW_P. */
13460 bool
13462 {
13465 {
13470 {
13479 /* For objects in symbol table check if we know they are non-zero.
13480 Don't do anything for variables and functions before symtab is built;
13481 it is quite possible that they will be declared weak later. */
13483 {
13489 else
13491 }
13493 /* Function local objects are never NULL. */
13500 /* Constants are never weak. */
13505 }
13513 {
13517 }
13522 }
13524 }
13526 #define integer_valued_real_p(X) \
13529 #define RECURSE(X) \
13530 ((integer_valued_real_p) (X, depth + 1))
13532 /* Return true if the floating point result of (CODE OP0) has an
13533 integer value. We also allow +Inf, -Inf and NaN to be considered
13534 integer values. Return false for signaling NaN.
13536 DEPTH is the current nesting depth of the query. */
13538 bool
13540 {
13542 {
13549 CASE_CONVERT:
13550 {
13557 }
13561 }
13563 }
13565 /* Return true if the floating point result of (CODE OP0 OP1) has an
13566 integer value. We also allow +Inf, -Inf and NaN to be considered
13567 integer values. Return false for signaling NaN.
13569 DEPTH is the current nesting depth of the query. */
13571 bool
13573 {
13575 {
13585 }
13587 }
13589 /* Return true if the floating point result of calling FNDECL with arguments
13590 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13591 considered integer values. Return false for signaling NaN. If FNDECL
13592 takes fewer than 2 arguments, the remaining ARGn are null.
13594 DEPTH is the current nesting depth of the query. */
13596 bool
13598 {
13600 {
13601 CASE_CFN_CEIL:
13602 CASE_CFN_FLOOR:
13603 CASE_CFN_NEARBYINT:
13604 CASE_CFN_RINT:
13605 CASE_CFN_ROUND:
13606 CASE_CFN_TRUNC:
13609 CASE_CFN_FMIN:
13610 CASE_CFN_FMAX:
13615 }
13617 }
13619 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13620 has an integer value. We also allow +Inf, -Inf and NaN to be
13621 considered integer values. Return false for signaling NaN.
13623 DEPTH is the current nesting depth of the query. */
13625 bool
13627 {
13629 {
13637 /* Limit the depth of recursion to avoid quadratic behavior.
13638 This is expected to catch almost all occurrences in practice.
13639 If this code misses important cases that unbounded recursion
13640 would not, passes that need this information could be revised
13641 to provide it through dataflow propagation. */
13645 depth));
13649 }
13651 }
13653 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13654 has an integer value. We also allow +Inf, -Inf and NaN to be
13655 considered integer values. Return false for signaling NaN.
13657 DEPTH is the current nesting depth of the query. */
13659 static bool
13661 {
13663 {
13674 }
13676 }
13678 #undef RECURSE
13679 #undef integer_valued_real_p
13681 /* Return true if the floating point expression T has an integer value.
13682 We also allow +Inf, -Inf and NaN to be considered integer values.
13683 Return false for signaling NaN.
13685 DEPTH is the current nesting depth of the query. */
13687 bool
13689 {
13695 {
13711 }
13714 {
13720 {
13729 }
13733 }
13734 }
13736 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13737 attempt to fold the expression to a constant without modifying TYPE,
13738 OP0 or OP1.
13740 If the expression could be simplified to a constant, then return
13741 the constant. If the expression would not be simplified to a
13742 constant, then return NULL_TREE. */
13744 tree
13746 {
13749 }
13751 /* Given the components of a unary expression CODE, TYPE and OP0,
13752 attempt to fold the expression to a constant without modifying
13753 TYPE or OP0.
13755 If the expression could be simplified to a constant, then return
13756 the constant. If the expression would not be simplified to a
13757 constant, then return NULL_TREE. */
13759 tree
13761 {
13764 }
13766 /* If EXP represents referencing an element in a constant string
13767 (either via pointer arithmetic or array indexing), return the
13768 tree representing the value accessed, otherwise return NULL. */
13770 tree
13772 {
13776 {
13778 tree index;
13779 tree string;
13784 else
13785 {
13789 /* Optimize the special-case of a zero lower bound.
13791 We convert the low_bound to sizetype to avoid some problems
13792 with constant folding. (E.g. suppose the lower bound is 1,
13793 and its mode is QI. Without the conversion,l (ARRAY
13794 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13795 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13801 }
13814 }
13816 }
13818 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13819 an integer constant, real, or fixed-point constant.
13821 TYPE is the type of the result. */
13823 static tree
13825 {
13829 {
13831 {
13838 }
13845 {
13846 FIXED_VALUE_TYPE f;
13851 /* Propagate overflow flags. */
13855 }
13859 }
13862 }
13864 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13865 an integer constant or real constant.
13867 TYPE is the type of the result. */
13869 tree
13871 {
13875 {
13877 {
13878 /* If the value is unsigned or non-negative, then the absolute value
13879 is the same as the ordinary value. */
13883 /* If the value is negative, then the absolute value is
13884 its negation. */
13885 else
13886 {
13891 }
13892 }
13898 else
13904 }
13907 }
13909 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13910 constant. TYPE is the type of the result. */
13912 static tree
13914 {
13918 }
13920 /* Given CODE, a relational operator, the target type, TYPE and two
13921 constant operands OP0 and OP1, return the result of the
13922 relational operation. If the result is not a compile time
13923 constant, then return NULL_TREE. */
13925 static tree
13927 {
13930 /* From here on, the only cases we handle are when the result is
13931 known to be a constant. */
13934 {
13938 /* Handle the cases where either operand is a NaN. */
13940 {
13942 {
13970 }
13973 }
13976 }
13979 {
13983 }
13985 /* Handle equality/inequality of complex constants. */
13987 {
13998 else
14000 }
14003 {
14005 {
14006 /* Have vector comparison with scalar boolean result. */
14011 {
14016 }
14020 }
14027 {
14039 }
14042 }
14044 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14046 To compute GT, swap the arguments and do LT.
14047 To compute GE, do LT and invert the result.
14048 To compute LE, swap the arguments, do LT and invert the result.
14049 To compute NE, do EQ and invert the result.
14051 Therefore, the code below must handle only EQ and LT. */
14054 {
14057 }
14059 /* Note that it is safe to invert for real values here because we
14060 have already handled the one case that it matters. */
14064 {
14067 }
14069 /* Compute a result for LT or EQ if args permit;
14070 Otherwise return T. */
14072 {
14075 else
14077 }
14078 else
14084 }
14086 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14087 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14088 itself. */
14090 tree
14092 {
14093 /* If the expression does not have side effects then we don't have to wrap
14094 it with a cleanup point expression. */
14098 /* If the expression is a return, check to see if the expression inside the
14099 return has no side effects or the right hand side of the modify expression
14100 inside the return. If either don't have side effects set we don't need to
14101 wrap the expression in a cleanup point expression. Note we don't check the
14102 left hand side of the modify because it should always be a return decl. */
14104 {
14111 }
14114 }
14116 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14117 of an indirection through OP0, or NULL_TREE if no simplification is
14118 possible. */
14120 tree
14122 {
14124 tree subtype;
14132 {
14135 /* *&CONST_DECL -> to the value of the const decl. */
14138 /* *&p => p; make sure to handle *&"str"[cst] here. */
14140 {
14144 else
14146 }
14147 /* *(foo *)&fooarray => fooarray[0] */
14150 && (!in_gimple_form
14152 {
14162 }
14163 /* *(foo *)&complexfoo => __real__ complexfoo */
14167 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14170 {
14174 }
14175 }
14179 {
14185 {
14186 tree op00type;
14190 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14193 {
14205 }
14206 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14209 {
14213 }
14214 /* ((foo *)&fooarray)[1] => fooarray[1] */
14217 {
14227 }
14228 }
14229 }
14231 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14234 && (!in_gimple_form
14236 {
14237 tree type_domain;
14247 NULL_TREE);
14248 }
14251 }
14253 /* Builds an expression for an indirection through T, simplifying some
14254 cases. */
14256 tree
14258 {
14266 }
14268 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14270 tree
14272 {
14277 else
14279 }
14281 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14282 whose result is ignored. The type of the returned tree need not be
14283 the same as the original expression. */
14285 tree
14287 {
14293 {
14304 else
14310 {
14326 }
14331 }
14332 }
14334 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14336 tree
14338 {
14344 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14345 have to do anything. Only do this when we are not given a const,
14346 because in that case, this check is more expensive than just
14347 doing it. */
14349 {
14354 }
14356 /* If divisor is a power of two, simplify this to bit manipulation. */
14358 {
14360 {
14374 }
14375 else
14376 {
14377 tree t;
14383 }
14384 }
14385 else
14386 {
14391 }
14394 }
14396 /* Likewise, but round down. */
14398 tree
14400 {
14407 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14408 have to do anything. Only do this when we are not given a const,
14409 because in that case, this check is more expensive than just
14410 doing it. */
14412 {
14417 }
14419 /* If divisor is a power of two, simplify this to bit manipulation. */
14421 {
14422 tree t;
14426 }
14427 else
14428 {
14433 }
14436 }
14438 /* Returns the pointer to the base of the object addressed by EXP and
14439 extracts the information about the offset of the access, storing it
14440 to PBITPOS and POFFSET. */
14442 static tree
14445 {
14446 tree core;
14447 machine_mode mode;
14449 HOST_WIDE_INT bitsize;
14453 {
14458 }
14459 else
14460 {
14464 }
14467 }
14469 /* Returns true if addresses of E1 and E2 differ by a constant, false
14470 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14472 bool
14474 {
14488 {
14498 }
14500 {
14501 /* If only one of the offsets is non-constant, the difference cannot
14502 be a constant. */
14504 }
14505 else
14510 }
14512 /* Return OFF converted to a pointer offset type suitable as offset for
14513 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14514 tree
14516 {
14518 }
14520 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14521 tree
14523 {
14526 }
14528 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14529 tree
14531 {
14534 }
14536 /* Return a char pointer for a C string if it is a string constant
14537 or sum of string constant and integer constant. */
14541 {
14542 tree offset_node;
14555 }