| blob | fa9d1bb20ff503231f77eb85ccbd548594d14c3f |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
85 /* Nonzero if we are folding constants inside an initializer; zero
86 otherwise. */
89 /* The following constants represent a bit based encoding of GCC's
90 comparison operators. This encoding simplifies transformations
91 on relational comparison operators, such as AND and OR. */
109 };
142 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
143 Otherwise, return LOC. */
145 static location_t
147 {
150 }
152 /* Similar to protected_set_expr_location, but never modify x in place,
153 if location can and needs to be set, unshare it. */
157 {
163 {
166 }
168 }
169 \f
170 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
171 division and returns the quotient. Otherwise returns
172 NULL_TREE. */
174 tree
176 {
177 widest_int quo;
184 }
185 \f
186 /* This is nonzero if we should defer warnings about undefined
187 overflow. This facility exists because these warnings are a
188 special case. The code to estimate loop iterations does not want
189 to issue any warnings, since it works with expressions which do not
190 occur in user code. Various bits of cleanup code call fold(), but
191 only use the result if it has certain characteristics (e.g., is a
192 constant); that code only wants to issue a warning if the result is
193 used. */
197 /* If a warning about undefined overflow is deferred, this is the
198 warning. Note that this may cause us to turn two warnings into
199 one, but that is fine since it is sufficient to only give one
200 warning per expression. */
204 /* If a warning about undefined overflow is deferred, this is the
205 level at which the warning should be emitted. */
209 /* Start deferring overflow warnings. We could use a stack here to
210 permit nested calls, but at present it is not necessary. */
212 void
214 {
216 }
218 /* Stop deferring overflow warnings. If there is a pending warning,
219 and ISSUE is true, then issue the warning if appropriate. STMT is
220 the statement with which the warning should be associated (used for
221 location information); STMT may be NULL. CODE is the level of the
222 warning--a warn_strict_overflow_code value. This function will use
223 the smaller of CODE and the deferred code when deciding whether to
224 issue the warning. CODE may be zero to mean to always use the
225 deferred code. */
227 void
229 {
231 location_t locus;
236 {
242 }
253 /* Use the smallest code level when deciding to issue the
254 warning. */
263 else
266 }
268 /* Stop deferring overflow warnings, ignoring any deferred
269 warnings. */
271 void
273 {
275 }
277 /* Whether we are deferring overflow warnings. */
279 bool
281 {
283 }
285 /* This is called when we fold something based on the fact that signed
286 overflow is undefined. */
288 void
290 {
292 {
295 {
298 }
299 }
302 }
303 \f
304 /* Return true if the built-in mathematical function specified by CODE
305 is odd, i.e. -f(x) == f(-x). */
307 bool
309 {
311 {
312 CASE_CFN_ASIN:
313 CASE_CFN_ASINH:
314 CASE_CFN_ATAN:
315 CASE_CFN_ATANH:
316 CASE_CFN_CASIN:
317 CASE_CFN_CASINH:
318 CASE_CFN_CATAN:
319 CASE_CFN_CATANH:
320 CASE_CFN_CBRT:
321 CASE_CFN_CPROJ:
322 CASE_CFN_CSIN:
323 CASE_CFN_CSINH:
324 CASE_CFN_CTAN:
325 CASE_CFN_CTANH:
326 CASE_CFN_ERF:
327 CASE_CFN_LLROUND:
328 CASE_CFN_LROUND:
329 CASE_CFN_ROUND:
330 CASE_CFN_SIN:
331 CASE_CFN_SINH:
332 CASE_CFN_TAN:
333 CASE_CFN_TANH:
334 CASE_CFN_TRUNC:
337 CASE_CFN_LLRINT:
338 CASE_CFN_LRINT:
339 CASE_CFN_NEARBYINT:
340 CASE_CFN_RINT:
345 }
347 }
349 /* Check whether we may negate an integer constant T without causing
350 overflow. */
352 bool
354 {
355 tree type;
364 }
366 /* Determine whether an expression T can be cheaply negated using
367 the function negate_expr without introducing undefined overflow. */
369 static bool
371 {
372 tree type;
381 {
386 /* Check that -CST will not overflow type. */
399 /* We want to canonicalize to positive real constants. Pretend
400 that only negative ones can be easily negated. */
408 {
419 }
434 /* -(A + B) -> (-B) - A. */
437 /* -(A + B) -> (-A) - B. */
441 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
450 /* INT_MIN/n * n doesn't overflow while negating one operand it does
451 if n is a (negative) power of two. */
460 /* Fall through. */
475 /* In general we can't negate B in A / B, because if A is INT_MIN and
476 B is 1, we may turn this into INT_MIN / -1 which is undefined
477 and actually traps on some architectures. */
486 /* Negate -((double)float) as (double)(-float). */
488 {
492 }
496 /* Negate -f(x) as f(-x). */
502 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
504 {
508 }
513 }
515 }
517 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
518 simplification is possible.
519 If negate_expr_p would return true for T, NULL_TREE will never be
520 returned. */
522 static tree
524 {
526 tree tem;
529 {
530 /* Convert - (~A) to A + 1. */
556 {
561 }
565 {
570 {
575 }
578 }
601 {
602 /* -(A + B) -> (-B) - A. */
604 {
608 }
610 /* -(A + B) -> (-A) - B. */
612 {
616 }
617 }
621 /* - (A - B) -> B - A */
632 /* Fall through. */
636 {
645 }
657 /* In general we can't negate B in A / B, because if A is INT_MIN and
658 B is 1, we may turn this into INT_MIN / -1 which is undefined
659 and actually traps on some architectures. */
671 /* Convert -((double)float) into (double)(-float). */
673 {
677 }
681 /* Negate -f(x) as f(-x). */
684 {
690 }
694 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
696 {
699 {
706 }
707 }
712 }
715 }
717 /* A wrapper for fold_negate_expr_1. */
719 static tree
721 {
728 }
730 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
731 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
732 return NULL_TREE. */
734 static tree
736 {
738 location_t loc;
751 }
752 \f
753 /* Split a tree IN into a constant, literal and variable parts that could be
754 combined with CODE to make IN. "constant" means an expression with
755 TREE_CONSTANT but that isn't an actual constant. CODE must be a
756 commutative arithmetic operation. Store the constant part into *CONP,
757 the literal in *LITP and return the variable part. If a part isn't
758 present, set it to null. If the tree does not decompose in this way,
759 return the entire tree as the variable part and the other parts as null.
761 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
762 case, we negate an operand that was subtracted. Except if it is a
763 literal for which we use *MINUS_LITP instead.
765 If NEGATE_P is true, we are negating all of IN, again except a literal
766 for which we use *MINUS_LITP instead. If a variable part is of pointer
767 type, it is negated after converting to TYPE. This prevents us from
768 generating illegal MINUS pointer expression. LOC is the location of
769 the converted variable part.
771 If IN is itself a literal or constant, return it as appropriate.
773 Note that we do not guarantee that any of the three values will be the
774 same type as IN, but they will have the same signedness and mode. */
776 static tree
780 {
788 /* Strip any conversions that don't change the machine mode or signedness. */
797 /* We can associate addition and subtraction together (even
798 though the C standard doesn't say so) for integers because
799 the value is not affected. For reals, the value might be
800 affected, so we can't. */
806 {
812 /* First see if either of the operands is a literal, then a constant. */
825 /* If we haven't dealt with either operand, this is not a case we can
826 decompose. Otherwise, VAR is either of the ones remaining, if any. */
831 else
834 /* Now do any needed negations. */
841 }
846 {
847 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
848 when IN is constant. */
851 }
852 else
856 {
869 }
879 }
881 /* Re-associate trees split by the above function. T1 and T2 are
882 either expressions to associate or null. Return the new
883 expression, if any. LOC is the location of the new expression. If
884 we build an operation, do it in TYPE and with CODE. */
886 static tree
888 {
890 {
893 }
897 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
898 try to fold this since we will have infinite recursion. But do
899 deal with any NEGATE_EXPRs. */
903 {
905 {
918 }
920 {
923 }
927 }
931 }
932 \f
933 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
934 for use in int_const_binop, size_binop and size_diffop. */
936 static bool
938 {
945 {
954 }
959 }
962 /* Combine two integer constants ARG1 and ARG2 under operation CODE
963 to produce a new constant. Return NULL_TREE if we don't know how
964 to evaluate CODE at compile-time. */
966 static tree
969 {
970 wide_int res;
971 tree t;
979 {
995 {
999 else
1001 }
1004 /* It's unclear from the C standard whether shifts can overflow.
1005 The following code ignores overflow; perhaps a C standard
1006 interpretation ruling is needed. */
1008 else
1015 {
1019 else
1021 }
1025 else
1104 }
1112 }
1114 tree
1116 {
1118 }
1120 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1121 constant. We assume ARG1 and ARG2 have the same data type, or at least
1122 are the same kind of constant and the same machine mode. Return zero if
1123 combining the constants is not allowed in the current operating mode. */
1125 static tree
1127 {
1128 /* Sanity check for the recursive cases. */
1136 {
1142 }
1145 {
1146 machine_mode mode;
1147 REAL_VALUE_TYPE d1;
1148 REAL_VALUE_TYPE d2;
1149 REAL_VALUE_TYPE value;
1150 REAL_VALUE_TYPE result;
1154 /* The following codes are handled by real_arithmetic. */
1156 {
1167 }
1175 /* Don't perform operation if we honor signaling NaNs and
1176 either operand is a signaling NaN. */
1182 /* Don't perform operation if it would raise a division
1183 by zero exception. */
1189 /* If either operand is a NaN, just return it. Otherwise, set up
1190 for floating-point trap; we return an overflow. */
1192 {
1193 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1194 is off. */
1198 }
1200 {
1201 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1202 is off. */
1206 }
1211 /* Don't constant fold this floating point operation if
1212 the result has overflowed and flag_trapping_math. */
1220 /* Don't constant fold this floating point operation if the
1221 result may dependent upon the run-time rounding mode and
1222 flag_rounding_math is set, or if GCC's software emulation
1223 is unable to accurately represent the result. */
1233 }
1236 {
1237 FIXED_VALUE_TYPE f1;
1238 FIXED_VALUE_TYPE f2;
1239 FIXED_VALUE_TYPE result;
1244 /* The following codes are handled by fixed_arithmetic. */
1246 {
1258 {
1265 }
1270 }
1277 /* Propagate overflow flags. */
1281 }
1284 {
1293 {
1304 mpc_mul);
1318 mpc_div);
1319 /* Fallthru. */
1325 {
1326 /* Keep this algorithm in sync with
1327 tree-complex.c:expand_complex_div_straight().
1329 Expand complex division to scalars, straightforward algorithm.
1330 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1331 t = br*br + bi*bi
1332 */
1333 tree magsquared
1337 tree t1
1341 tree t2
1348 }
1349 else
1350 {
1351 /* Keep this algorithm in sync with
1352 tree-complex.c:expand_complex_div_wide().
1354 Expand complex division to scalars, modified algorithm to minimize
1355 overflow with wide input ranges. */
1361 {
1362 /* In the TRUE branch, we compute
1363 ratio = br/bi;
1364 div = (br * ratio) + bi;
1365 tr = (ar * ratio) + ai;
1366 ti = (ai * ratio) - ar;
1367 tr = tr / div;
1368 ti = ti / div; */
1379 }
1380 else
1381 {
1382 /* In the FALSE branch, we compute
1383 ratio = d/c;
1384 divisor = (d * ratio) + c;
1385 tr = (b * ratio) + a;
1386 ti = b - (a * ratio);
1387 tr = tr / div;
1388 ti = ti / div; */
1400 }
1401 }
1406 }
1410 }
1414 {
1420 {
1426 /* It is possible that const_binop cannot handle the given
1427 code and return NULL_TREE */
1431 }
1434 }
1436 /* Shifts allow a scalar offset for a vector. */
1439 {
1445 {
1450 /* It is possible that const_binop cannot handle the given
1451 code and return NULL_TREE. */
1455 }
1458 }
1460 }
1462 /* Overload that adds a TYPE parameter to be able to dispatch
1463 to fold_relational_const. */
1465 tree
1467 {
1471 /* ??? Until we make the const_binop worker take the type of the
1472 result as argument put those cases that need it here. */
1474 {
1485 {
1499 {
1509 }
1512 }
1518 {
1540 {
1553 }
1556 }
1559 }
1564 /* Make sure type and arg0 have the same saturating flag. */
1569 }
1571 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1572 Return zero if computing the constants is not possible. */
1574 tree
1576 {
1577 /* Don't perform the operation, other than NEGATE and ABS, if
1578 flag_signaling_nans is on and the operand is a signaling NaN. */
1587 {
1588 CASE_CONVERT:
1595 /* If the source address is 0, and the source address space
1596 cannot have a valid object at 0, fold to dest type null. */
1607 {
1608 /* Can't call fold_negate_const directly here as that doesn't
1609 handle all cases and we might not be able to negate some
1610 constants. */
1615 }
1624 {
1628 }
1634 /* Perform BIT_NOT_EXPR on each element individually. */
1636 {
1637 tree elem;
1642 {
1648 }
1651 }
1673 {
1691 else
1696 {
1702 }
1705 }
1710 {
1719 {
1724 }
1728 {
1732 }
1735 }
1739 }
1742 }
1744 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1745 indicates which particular sizetype to create. */
1747 tree
1749 {
1751 }
1752 \f
1753 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1754 is a tree code. The type of the result is taken from the operands.
1755 Both must be equivalent integer types, ala int_binop_types_match_p.
1756 If the operands are constant, so is the result. */
1758 tree
1760 {
1769 /* Handle the special case of two integer constants faster. */
1771 {
1772 /* And some specific cases even faster than that. */
1774 {
1779 }
1781 {
1784 }
1786 {
1789 }
1791 /* Handle general case of two integer constants. For sizetype
1792 constant calculations we always want to know about overflow,
1793 even in the unsigned case. */
1795 }
1798 }
1800 /* Given two values, either both of sizetype or both of bitsizetype,
1801 compute the difference between the two values. Return the value
1802 in signed type corresponding to the type of the operands. */
1804 tree
1806 {
1808 tree ctype;
1813 /* If the type is already signed, just do the simple thing. */
1821 else
1824 /* If either operand is not a constant, do the conversions to the signed
1825 type and subtract. The hardware will do the right thing with any
1826 overflow in the subtraction. */
1832 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1833 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1834 overflow) and negate (which can't either). Special-case a result
1835 of zero while we're here. */
1841 else
1845 MINUS_EXPR,
1847 }
1848 \f
1849 /* A subroutine of fold_convert_const handling conversions of an
1850 INTEGER_CST to another integer type. */
1852 static tree
1854 {
1855 /* Given an integer constant, make new constant with new type,
1856 appropriately sign-extended or truncated. Use widest_int
1857 so that any extension is done according ARG1's type. */
1861 }
1863 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1864 to an integer type. */
1866 static tree
1868 {
1870 tree t;
1872 /* The following code implements the floating point to integer
1873 conversion rules required by the Java Language Specification,
1874 that IEEE NaNs are mapped to zero and values that overflow
1875 the target precision saturate, i.e. values greater than
1876 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1877 are mapped to INT_MIN. These semantics are allowed by the
1878 C and C++ standards that simply state that the behavior of
1879 FP-to-integer conversion is unspecified upon overflow. */
1881 wide_int val;
1882 REAL_VALUE_TYPE r;
1886 {
1893 }
1895 /* If R is NaN, return zero and show we have an overflow. */
1897 {
1900 }
1902 /* See if R is less than the lower bound or greater than the
1903 upper bound. */
1906 {
1910 {
1913 }
1914 }
1917 {
1920 {
1923 {
1926 }
1927 }
1928 }
1935 }
1937 /* A subroutine of fold_convert_const handling conversions of a
1938 FIXED_CST to an integer type. */
1940 static tree
1942 {
1943 tree t;
1945 scalar_mode mode;
1947 /* Right shift FIXED_CST to temp by fbit. */
1951 {
1953 HOST_BITS_PER_DOUBLE_INT,
1956 /* Left shift temp to temp_trunc by fbit. */
1958 HOST_BITS_PER_DOUBLE_INT,
1960 }
1961 else
1962 {
1965 }
1967 /* If FIXED_CST is negative, we need to round the value toward 0.
1968 By checking if the fractional bits are not zero to add 1 to temp. */
1974 /* Given a fixed-point constant, make new constant with new type,
1975 appropriately sign-extended or truncated. */
1983 }
1985 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1986 to another floating point type. */
1988 static tree
1990 {
1991 REAL_VALUE_TYPE value;
1992 tree t;
1994 /* Don't perform the operation if flag_signaling_nans is on
1995 and the operand is a signaling NaN. */
2003 /* If converting an infinity or NAN to a representation that doesn't
2004 have one, set the overflow bit so that we can produce some kind of
2005 error message at the appropriate point if necessary. It's not the
2006 most user-friendly message, but it's better than nothing. */
2013 /* Regular overflow, conversion produced an infinity in a mode that
2014 can't represent them. */
2019 else
2022 }
2024 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2025 to a floating point type. */
2027 static tree
2029 {
2030 REAL_VALUE_TYPE value;
2031 tree t;
2039 }
2041 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2042 to another fixed-point type. */
2044 static tree
2046 {
2047 FIXED_VALUE_TYPE value;
2048 tree t;
2055 /* Propagate overflow flags. */
2059 }
2061 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2062 to a fixed-point type. */
2064 static tree
2066 {
2067 FIXED_VALUE_TYPE value;
2068 tree t;
2070 double_int di;
2077 else
2085 /* Propagate overflow flags. */
2089 }
2091 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2092 to a fixed-point type. */
2094 static tree
2096 {
2097 FIXED_VALUE_TYPE value;
2098 tree t;
2106 /* Propagate overflow flags. */
2110 }
2112 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2113 type TYPE. If no simplification can be done return NULL_TREE. */
2115 static tree
2117 {
2123 {
2130 }
2132 {
2139 }
2141 {
2148 }
2150 {
2153 {
2158 {
2164 }
2166 }
2167 }
2169 }
2171 /* Construct a vector of zero elements of vector type TYPE. */
2173 static tree
2175 {
2176 tree t;
2180 }
2182 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2184 bool
2186 {
2201 {
2216 }
2217 }
2219 /* Convert expression ARG to type TYPE. Used by the middle-end for
2220 simple conversions in preference to calling the front-end's convert. */
2222 tree
2224 {
2226 tree tem;
2237 {
2240 /* Handle conversions between pointers to different address spaces. */
2245 /* fall through */
2250 {
2254 }
2268 {
2272 }
2274 {
2278 }
2280 {
2284 }
2287 {
2305 }
2310 {
2314 }
2317 {
2331 }
2335 {
2344 integer_zero_node));
2346 {
2350 {
2356 }
2364 }
2368 }
2386 }
2387 fold_convert_exit:
2390 }
2391 \f
2392 /* Return false if expr can be assumed not to be an lvalue, true
2393 otherwise. */
2395 static bool
2397 {
2398 /* We only need to wrap lvalue tree codes. */
2400 {
2431 /* Assume the worst for front-end tree codes. */
2435 }
2438 }
2440 /* Return an expr equal to X but certainly not valid as an lvalue. */
2442 tree
2444 {
2445 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2446 us. */
2453 }
2455 /* When pedantic, return an expr equal to X but certainly not valid as a
2456 pedantic lvalue. Otherwise, return X. */
2458 static tree
2460 {
2462 }
2463 \f
2464 /* Given a tree comparison code, return the code that is the logical inverse.
2465 It is generally not safe to do this for floating-point comparisons, except
2466 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2467 ERROR_MARK in this case. */
2469 enum tree_code
2471 {
2477 {
2508 }
2509 }
2511 /* Similar, but return the comparison that results if the operands are
2512 swapped. This is safe for floating-point. */
2514 enum tree_code
2516 {
2518 {
2544 }
2545 }
2548 /* Convert a comparison tree code from an enum tree_code representation
2549 into a compcode bit-based encoding. This function is the inverse of
2550 compcode_to_comparison. */
2552 static enum comparison_code
2554 {
2556 {
2587 }
2588 }
2590 /* Convert a compcode bit-based encoding of a comparison operator back
2591 to GCC's enum tree_code representation. This function is the
2592 inverse of comparison_to_compcode. */
2594 static enum tree_code
2596 {
2598 {
2629 }
2630 }
2632 /* Return a tree for the comparison which is the combination of
2633 doing the AND or OR (depending on CODE) of the two operations LCODE
2634 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2635 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2636 if this makes the transformation invalid. */
2638 tree
2643 {
2650 {
2661 }
2664 {
2665 /* Eliminate unordered comparisons, as well as LTGT and ORD
2666 which are not used unless the mode has NaNs. */
2672 }
2674 {
2675 /* Check that the original operation and the optimized ones will trap
2676 under the same condition. */
2687 /* In a short-circuited boolean expression the LHS might be
2688 such that the RHS, if evaluated, will never trap. For
2689 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2690 if neither x nor y is NaN. (This is a mixed blessing: for
2691 example, the expression above will never trap, hence
2692 optimizing it to x < y would be invalid). */
2697 /* If the comparison was short-circuited, and only the RHS
2698 trapped, we may now generate a spurious trap. */
2703 /* If we changed the conditions that cause a trap, we lose. */
2706 }
2712 else
2713 {
2718 }
2719 }
2720 \f
2721 /* Return nonzero if two operands (typically of the same tree node)
2722 are necessarily equal. FLAGS modifies behavior as follows:
2724 If OEP_ONLY_CONST is set, only return nonzero for constants.
2725 This function tests whether the operands are indistinguishable;
2726 it does not test whether they are equal using C's == operation.
2727 The distinction is important for IEEE floating point, because
2728 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2729 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2731 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2732 even though it may hold multiple values during a function.
2733 This is because a GCC tree node guarantees that nothing else is
2734 executed between the evaluation of its "operands" (which may often
2735 be evaluated in arbitrary order). Hence if the operands themselves
2736 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2737 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2738 unset means assuming isochronic (or instantaneous) tree equivalence.
2739 Unless comparing arbitrary expression trees, such as from different
2740 statements, this flag can usually be left unset.
2742 If OEP_PURE_SAME is set, then pure functions with identical arguments
2743 are considered the same. It is used when the caller has other ways
2744 to ensure that global memory is unchanged in between.
2746 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2747 not values of expressions.
2749 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2750 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2752 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2753 any operand with side effect. This is unnecesarily conservative in the
2754 case we know that arg0 and arg1 are in disjoint code paths (such as in
2755 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2756 addresses with TREE_CONSTANT flag set so we know that &var == &var
2757 even if var is volatile. */
2759 int
2761 {
2762 /* When checking, verify at the outermost operand_equal_p call that
2763 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2764 hash value. */
2766 {
2768 {
2770 {
2777 }
2779 }
2780 else
2782 }
2784 /* If either is ERROR_MARK, they aren't equal. */
2790 /* Similar, if either does not have a type (like a released SSA name),
2791 they aren't equal. */
2795 /* We cannot consider pointers to different address space equal. */
2802 /* Check equality of integer constants before bailing out due to
2803 precision differences. */
2805 {
2806 /* Address of INTEGER_CST is not defined; check that we did not forget
2807 to drop the OEP_ADDRESS_OF flags. */
2810 }
2813 {
2814 /* If both types don't have the same signedness, then we can't consider
2815 them equal. We must check this before the STRIP_NOPS calls
2816 because they may change the signedness of the arguments. As pointers
2817 strictly don't have a signedness, require either two pointers or
2818 two non-pointers as well. */
2824 /* If both types don't have the same precision, then it is not safe
2825 to strip NOPs. */
2832 }
2833 #if 0
2834 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2835 sanity check once the issue is solved. */
2836 else
2837 /* Addresses of conversions and SSA_NAMEs (and many other things)
2838 are not defined. Check that we did not forget to drop the
2839 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2842 #endif
2844 /* In case both args are comparisons but with different comparison
2845 code, try to swap the comparison operands of one arg to produce
2846 a match and compare that variant. */
2850 {
2858 }
2861 {
2862 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2864 ;
2866 {
2867 /* If we are interested in comparing addresses ignore
2868 MEM_REF wrappings of the base that can appear just for
2869 TBAA reasons. */
2883 }
2884 else
2886 }
2888 /* When not checking adddresses, this is needed for conversions and for
2889 COMPONENT_REF. Might as well play it safe and always test this. */
2896 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2897 We don't care about side effects in that case because the SAVE_EXPR
2898 takes care of that for us. In all other cases, two expressions are
2899 equal if they have no side effects. If we have two identical
2900 expressions with side effects that should be treated the same due
2901 to the only side effects being identical SAVE_EXPR's, that will
2902 be detected in the recursive calls below.
2903 If we are taking an invariant address of two identical objects
2904 they are necessarily equal as well. */
2911 /* Next handle constant cases, those for which we can return 1 even
2912 if ONLY_CONST is set. */
2915 {
2929 {
2930 /* If we do not distinguish between signed and unsigned zero,
2931 consider them equal. */
2934 }
2938 {
2945 {
2949 }
2951 }
2955 flags)
2957 flags));
2968 flags | OEP_ADDRESS_OF
2971 /* In GIMPLE empty constructors are allowed in initializers of
2972 aggregates. */
2976 }
2981 /* Define macros to test an operand from arg0 and arg1 for equality and a
2982 variant that allows null and views null as being different from any
2983 non-null value. In the latter case, if either is null, the both
2984 must be; otherwise, do the normal comparison. */
2985 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2986 TREE_OPERAND (arg1, N), flags)
2988 #define OP_SAME_WITH_NULL(N) \
2989 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2990 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2993 {
2995 /* Two conversions are equal only if signedness and modes match. */
2997 {
2998 CASE_CONVERT:
3006 }
3016 /* For commutative ops, allow the other order. */
3024 /* If either of the pointer (or reference) expressions we are
3025 dereferencing contain a side effect, these cannot be equal,
3026 but their addresses can be. */
3033 {
3043 /* Require the same offset. */
3049 /* Fallthru. */
3057 {
3058 /* Require equal access sizes */
3064 flags)))
3066 /* Verify that access happens in similar types. */
3069 /* Verify that accesses are TBAA compatible. */
3078 /* Verify that alignment is compatible. */
3082 }
3085 /* TARGET_MEM_REF require equal extra operands. */
3096 /* Compare the array index by value if it is constant first as we
3097 may have different types but same value here. */
3103 /* Compare low bound and element size as with OEP_ADDRESS_OF
3104 we have to account for the offset of the ref. */
3109 array_ref_low_bound
3113 array_ref_element_size
3115 flags))));
3118 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3119 may be NULL when we're called to compare MEM_EXPRs. */
3134 }
3138 {
3140 /* Be sure we pass right ADDRESS_OF flag. */
3158 /* The multiplcation operands are commutative. */
3159 /* FALLTHRU */
3167 /* Otherwise take into account this is a commutative operation. */
3180 /* BIT_INSERT_EXPR has an implict operand as the type precision
3181 of op1. Need to check to make sure they are the same. */
3187 /* FALLTHRU */
3212 }
3216 {
3220 /* If not both CALL_EXPRs are either internal or normal function
3221 functions, then they are not equal. */
3224 {
3225 /* If the CALL_EXPRs call different internal functions, then they
3226 are not equal. */
3229 }
3230 else
3231 {
3232 /* If the CALL_EXPRs call different functions, then they are not
3233 equal. */
3235 flags))
3237 }
3239 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3240 {
3244 else
3248 }
3250 /* Now see if all the arguments are the same. */
3251 {
3262 /* If we get here and both argument lists are exhausted
3263 then the CALL_EXPRs are equal. */
3265 }
3268 }
3271 /* Consider __builtin_sqrt equal to sqrt. */
3279 {
3280 /* In GIMPLE constructors are used only to build vectors from
3281 elements. Individual elements in the constructor must be
3282 indexed in increasing order and form an initial sequence.
3284 We make no effort to compare constructors in generic.
3285 (see sem_variable::equals in ipa-icf which can do so for
3286 constants). */
3291 /* Be sure that vectors constructed have the same representation.
3292 We only tested element precision and modes to match.
3293 Vectors may be BLKmode and thus also check that the number of
3294 parts match. */
3307 {
3312 /* In GIMPLE the indexes can be either NULL or matching i.
3313 Double check this so we won't get false
3314 positives for GENERIC. */
3322 }
3324 }
3327 {
3328 /* Compare the STATEMENT_LISTs. */
3334 {
3335 /* The lists don't have the same number of statements. */
3341 OEP_LEXICOGRAPHIC))
3343 }
3344 }
3349 {
3356 }
3360 }
3362 #undef OP_SAME
3363 #undef OP_SAME_WITH_NULL
3364 }
3365 \f
3366 /* Similar to operand_equal_p, but strip nops first. */
3368 static bool
3370 {
3378 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3379 and see if the inner values are the same. This removes any
3380 signedness comparison, which doesn't matter here. */
3387 }
3388 \f
3389 /* See if ARG is an expression that is either a comparison or is performing
3390 arithmetic on comparisons. The comparisons must only be comparing
3391 two different values, which will be stored in *CVAL1 and *CVAL2; if
3392 they are nonzero it means that some operands have already been found.
3393 No variables may be used anywhere else in the expression except in the
3394 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3395 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3397 If this is true, return 1. Otherwise, return zero. */
3399 static int
3401 {
3405 /* We can handle some of the tcc_expression cases here. */
3415 {
3416 /* If we've already found a CVAL1 or CVAL2, this expression is
3417 two complex to handle. */
3423 }
3426 {
3449 /* First see if we can handle the first operand, then the second. For
3450 the second operand, we know *CVAL1 can't be zero. It must be that
3451 one side of the comparison is each of the values; test for the
3452 case where this isn't true by failing if the two operands
3453 are the same. */
3462 ;
3466 ;
3467 else
3471 ;
3475 ;
3476 else
3483 }
3484 }
3485 \f
3486 /* ARG is a tree that is known to contain just arithmetic operations and
3487 comparisons. Evaluate the operations in the tree substituting NEW0 for
3488 any occurrence of OLD0 as an operand of a comparison and likewise for
3489 NEW1 and OLD1. */
3491 static tree
3494 {
3499 /* We can handle some of the tcc_expression cases here. */
3507 {
3522 {
3541 }
3542 /* Fall through - ??? */
3545 {
3549 /* We need to check both for exact equality and tree equality. The
3550 former will be true if the operand has a side-effect. In that
3551 case, we know the operand occurred exactly once. */
3564 }
3568 }
3569 }
3570 \f
3571 /* Return a tree for the case when the result of an expression is RESULT
3572 converted to TYPE and OMITTED was previously an operand of the expression
3573 but is now not needed (e.g., we folded OMITTED * 0).
3575 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3576 the conversion of RESULT to TYPE. */
3578 tree
3580 {
3583 /* If the resulting operand is an empty statement, just return the omitted
3584 statement casted to void. */
3594 }
3596 /* Return a tree for the case when the result of an expression is RESULT
3597 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3598 of the expression but are now not needed.
3600 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3601 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3602 evaluated before OMITTED2. Otherwise, if neither has side effects,
3603 just do the conversion of RESULT to TYPE. */
3605 tree
3608 {
3617 }
3619 \f
3620 /* Return a simplified tree node for the truth-negation of ARG. This
3621 never alters ARG itself. We assume that ARG is an operation that
3622 returns a truth value (0 or 1).
3624 FIXME: one would think we would fold the result, but it causes
3625 problems with the dominator optimizer. */
3627 static tree
3629 {
3634 /* If this is a comparison, we can simply invert it, except for
3635 floating-point non-equality comparisons, in which case we just
3636 enclose a TRUTH_NOT_EXPR around what we have. */
3639 {
3642 && flag_trapping_math
3656 }
3659 {
3678 /* Here we can invert either operand. We invert the first operand
3679 unless the second operand is a TRUTH_NOT_EXPR in which case our
3680 result is the XOR of the first operand with the inside of the
3681 negation of the second operand. */
3686 else
3709 {
3716 /* A COND_EXPR may have a throw as one operand, which
3717 then has void type. Just leave void operands
3718 as they are. */
3724 }
3736 CASE_CONVERT:
3740 /* fall through */
3762 }
3763 }
3765 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3766 assume that ARG is an operation that returns a truth value (0 or 1
3767 for scalars, 0 or -1 for vectors). Return the folded expression if
3768 folding is successful. Otherwise, return NULL_TREE. */
3770 static tree
3772 {
3775 ? BIT_NOT_EXPR
3778 }
3780 /* Return a simplified tree node for the truth-negation of ARG. This
3781 never alters ARG itself. We assume that ARG is an operation that
3782 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3784 tree
3786 {
3792 ? BIT_NOT_EXPR
3795 }
3797 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3798 with code CODE. This optimization is unsafe. */
3799 static tree
3802 {
3806 /* (A / C) +- (B / C) -> (A +- B) / C. */
3816 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3821 {
3833 }
3836 }
3837 \f
3838 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3839 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3840 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3841 is the original memory reference used to preserve the alias set of
3842 the access. */
3844 static tree
3848 {
3851 /* Attempt not to lose the access path if possible. */
3853 {
3855 machine_mode nmode;
3857 tree noffset;
3867 && !reversep
3868 && !nreversep
3870 {
3873 }
3874 }
3883 {
3890 }
3905 }
3907 /* Optimize a bit-field compare.
3909 There are two cases: First is a compare against a constant and the
3910 second is a comparison of two items where the fields are at the same
3911 bit position relative to the start of a chunk (byte, halfword, word)
3912 large enough to contain it. In these cases we can avoid the shift
3913 implicit in bitfield extractions.
3915 For constants, we emit a compare of the shifted constant with the
3916 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3917 compared. For two fields at the same position, we do the ANDs with the
3918 similar mask and compare the result of the ANDs.
3920 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3921 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3922 are the left and right operands of the comparison, respectively.
3924 If the optimization described above can be done, we return the resulting
3925 tree. Otherwise we return zero. */
3927 static tree
3930 {
3933 tree unsigned_type;
3936 scalar_int_mode nmode;
3941 tree mask;
3942 tree offset;
3944 /* Get all the information about the extractions being done. If the bit size
3945 if the same as the size of the underlying object, we aren't doing an
3946 extraction at all and so can do nothing. We also don't want to
3947 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3948 then will no longer be able to replace it. */
3957 else
3958 {
3959 /* If this is not a constant, we can only do something if bit positions,
3960 sizes, signedness and storage order are the same. */
3961 rinner
3969 }
3971 /* Honor the C++ memory model and mimic what RTL expansion does. */
3975 {
3979 }
3981 /* See if we can find a mode to refer to this field. We should be able to,
3982 but fail if we can't. */
3990 /* Set signed and unsigned types of the precision of this mode for the
3991 shifts below. */
3994 /* Compute the bit position and size for the new reference and our offset
3995 within it. If the new reference is the same size as the original, we
3996 won't optimize anything, so return zero. */
4006 /* Make the mask to be used against the extracted field. */
4013 /* If not comparing with constant, just rework the comparison
4014 and return. */
4018 unsigned_type,
4021 mask),
4024 unsigned_type,
4027 mask));
4029 /* Otherwise, we are handling the constant case. See if the constant is too
4030 big for the field. Warn and return a tree for 0 (false) if so. We do
4031 this not only for its own sake, but to avoid having to test for this
4032 error case below. If we didn't, we might generate wrong code.
4034 For unsigned fields, the constant shifted right by the field length should
4035 be all zero. For signed fields, the high-order bits should agree with
4036 the sign bit. */
4039 {
4041 {
4045 }
4046 }
4047 else
4048 {
4051 {
4055 }
4056 }
4058 /* Single-bit compares should always be against zero. */
4060 {
4063 }
4065 /* Make a new bitfield reference, shift the constant over the
4066 appropriate number of bits and mask it with the computed mask
4067 (in case this was a signed field). If we changed it, make a new one. */
4075 mask);
4080 }
4081 \f
4082 /* Subroutine for fold_truth_andor_1: decode a field reference.
4084 If EXP is a comparison reference, we return the innermost reference.
4086 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4087 set to the starting bit number.
4089 If the innermost field can be completely contained in a mode-sized
4090 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4092 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4093 otherwise it is not changed.
4095 *PUNSIGNEDP is set to the signedness of the field.
4097 *PREVERSEP is set to the storage order of the field.
4099 *PMASK is set to the mask used. This is either contained in a
4100 BIT_AND_EXPR or derived from the width of the field.
4102 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4104 Return 0 if this is not a component reference or is one that we can't
4105 do anything with. */
4107 static tree
4112 {
4117 tree unsigned_type;
4120 /* All the optimizations using this function assume integer fields.
4121 There are problems with FP fields since the type_for_size call
4122 below can fail for, e.g., XFmode. */
4126 /* We are interested in the bare arrangement of bits, so strip everything
4127 that doesn't affect the machine mode. However, record the type of the
4128 outermost expression if it may matter below. */
4135 {
4141 }
4148 /* Reject out-of-bound accesses (PR79731). */
4156 /* If the number of bits in the reference is the same as the bitsize of
4157 the outer type, then the outer type gives the signedness. Otherwise
4158 (in case of a small bitfield) the signedness is unchanged. */
4162 /* Compute the mask to access the bitfield. */
4171 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4179 }
4181 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4182 bit positions and MASK is SIGNED. */
4184 static int
4186 {
4190 /* If this function returns true when the type of the mask is
4191 UNSIGNED, then there will be errors. In particular see
4192 gcc.c-torture/execute/990326-1.c. There does not appear to be
4193 any documentation paper trail as to why this is so. But the pre
4194 wide-int worked with that restriction and it has been preserved
4195 here. */
4200 }
4202 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4203 represents the sign bit of EXP's type. If EXP represents a sign
4204 or zero extension, also test VAL against the unextended type.
4205 The return value is the (sub)expression whose sign bit is VAL,
4206 or NULL_TREE otherwise. */
4208 tree
4210 {
4212 tree t;
4214 /* Tree EXP must have an integral type. */
4219 /* Tree VAL must be an integer constant. */
4228 /* Handle extension from a narrower type. */
4234 }
4236 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4237 to be evaluated unconditionally. */
4239 static int
4241 {
4242 /* Strip any conversions that don't change the machine mode. */
4251 /* Don't regard global variables as simple. They may be
4252 allocated in ways unknown to the compiler (shared memory,
4253 #pragma weak, etc). */
4256 /* Weakrefs are not safe to be read, since they can be NULL.
4257 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4258 have DECL_WEAK flag set. */
4260 /* Loading a static variable is unduly expensive, but global
4261 registers aren't expensive. */
4263 }
4265 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4266 to be evaluated unconditionally.
4267 I addition to simple_operand_p, we assume that comparisons, conversions,
4268 and logic-not operations are simple, if their operands are simple, too. */
4270 static bool
4272 {
4292 }
4294 \f
4295 /* The following functions are subroutines to fold_range_test and allow it to
4296 try to change a logical combination of comparisons into a range test.
4298 For example, both
4299 X == 2 || X == 3 || X == 4 || X == 5
4300 and
4301 X >= 2 && X <= 5
4302 are converted to
4303 (unsigned) (X - 2) <= 3
4305 We describe each set of comparisons as being either inside or outside
4306 a range, using a variable named like IN_P, and then describe the
4307 range with a lower and upper bound. If one of the bounds is omitted,
4308 it represents either the highest or lowest value of the type.
4310 In the comments below, we represent a range by two numbers in brackets
4311 preceded by a "+" to designate being inside that range, or a "-" to
4312 designate being outside that range, so the condition can be inverted by
4313 flipping the prefix. An omitted bound is represented by a "-". For
4314 example, "- [-, 10]" means being outside the range starting at the lowest
4315 possible value and ending at 10, in other words, being greater than 10.
4316 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4317 always false.
4319 We set up things so that the missing bounds are handled in a consistent
4320 manner so neither a missing bound nor "true" and "false" need to be
4321 handled using a special case. */
4323 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4324 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4325 and UPPER1_P are nonzero if the respective argument is an upper bound
4326 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4327 must be specified for a comparison. ARG1 will be converted to ARG0's
4328 type if both are specified. */
4330 static tree
4333 {
4334 tree tem;
4338 /* If neither arg represents infinity, do the normal operation.
4339 Else, if not a comparison, return infinity. Else handle the special
4340 comparison rules. Note that most of the cases below won't occur, but
4341 are handled for consistency. */
4344 {
4349 }
4354 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4355 for neither. In real maths, we cannot assume open ended ranges are
4356 the same. But, this is computer arithmetic, where numbers are finite.
4357 We can therefore make the transformation of any unbounded range with
4358 the value Z, Z being greater than any representable number. This permits
4359 us to treat unbounded ranges as equal. */
4363 {
4384 }
4387 }
4388 \f
4389 /* Helper routine for make_range. Perform one step for it, return
4390 new expression if the loop should continue or NULL_TREE if it should
4391 stop. */
4393 tree
4397 {
4403 {
4405 /* We can only do something if the range is testing for zero. */
4414 /* We can only do something if the range is testing for zero
4415 and if the second operand is an integer constant. Note that
4416 saying something is "in" the range we make is done by
4417 complementing IN_P since it will set in the initial case of
4418 being not equal to zero; "out" is leaving it alone. */
4425 {
4446 }
4448 /* If this is an unsigned comparison, we also know that EXP is
4449 greater than or equal to zero. We base the range tests we make
4450 on that fact, so we record it here so we can parse existing
4451 range tests. We test arg0_type since often the return type
4452 of, e.g. EQ_EXPR, is boolean. */
4454 {
4458 NULL_TREE))
4463 /* If the high bound is missing, but we have a nonzero low
4464 bound, reverse the range so it goes from zero to the low bound
4465 minus 1. */
4467 {
4472 }
4473 }
4481 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4482 low and high are non-NULL, then normalize will DTRT. */
4485 {
4490 }
4492 /* (-x) IN [a,b] -> x in [-b, -a] */
4504 /* ~ X -> -X - 1 */
4513 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4514 move a constant to the other side. */
4519 /* If EXP is signed, any overflow in the computation is undefined,
4520 so we don't worry about it so long as our computations on
4521 the bounds don't overflow. For unsigned, overflow is defined
4522 and this is exactly the right thing. */
4534 normalize:
4535 /* Check for an unsigned range which has wrapped around the maximum
4536 value thus making n_high < n_low, and normalize it. */
4538 {
4544 /* If the range is of the form +/- [ x+1, x ], we won't
4545 be able to normalize it. But then, it represents the
4546 whole range or the empty set, so make it
4547 +/- [ -, - ]. */
4551 else
4553 }
4554 else
4562 CASE_CONVERT:
4580 /* If we're converting arg0 from an unsigned type, to exp,
4581 a signed type, we will be doing the comparison as unsigned.
4582 The tests above have already verified that LOW and HIGH
4583 are both positive.
4585 So we have to ensure that we will handle large unsigned
4586 values the same way that the current signed bounds treat
4587 negative values. */
4590 {
4591 tree high_positive;
4592 tree equiv_type;
4593 /* For fixed-point modes, we need to pass the saturating flag
4594 as the 2nd parameter. */
4596 equiv_type
4599 else
4600 equiv_type
4603 /* A range without an upper bound is, naturally, unbounded.
4604 Since convert would have cropped a very large value, use
4605 the max value for the destination type. */
4606 high_positive
4613 high_positive),
4616 /* If the low bound is specified, "and" the range with the
4617 range for which the original unsigned value will be
4618 positive. */
4620 {
4623 integer_zero_node),
4624 high_positive))
4628 }
4629 else
4630 {
4631 /* Otherwise, "or" the range with the range of the input
4632 that will be interpreted as negative. */
4635 integer_zero_node),
4636 high_positive))
4640 }
4641 }
4650 }
4651 }
4653 /* Given EXP, a logical expression, set the range it is testing into
4654 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4655 actually being tested. *PLOW and *PHIGH will be made of the same
4656 type as the returned expression. If EXP is not a comparison, we
4657 will most likely not be returning a useful value and range. Set
4658 *STRICT_OVERFLOW_P to true if the return value is only valid
4659 because signed overflow is undefined; otherwise, do not change
4660 *STRICT_OVERFLOW_P. */
4662 tree
4665 {
4673 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4674 and see if we can refine the range. Some of the cases below may not
4675 happen, but it doesn't seem worth worrying about this. We "continue"
4676 the outer loop when we've changed something; otherwise we "break"
4677 the switch, which will "break" the while. */
4683 {
4689 {
4697 }
4706 }
4708 /* If EXP is a constant, we can evaluate whether this is true or false. */
4710 {
4717 }
4721 }
4723 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4724 a bitwise check i.e. when
4725 LOW == 0xXX...X00...0
4726 HIGH == 0xXX...X11...1
4727 Return corresponding mask in MASK and stem in VALUE. */
4729 static bool
4732 {
4755 }
4756 \f
4757 /* Helper routine for build_range_check and match.pd. Return the type to
4758 perform the check or NULL if it shouldn't be optimized. */
4760 tree
4762 {
4763 /* First make sure that arithmetics in this type is valid, then make sure
4764 that it wraps around. */
4770 {
4773 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4774 for the type in question, as we rely on this here. */
4784 else
4786 }
4788 }
4790 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4791 type, TYPE, return an expression to test if EXP is in (or out of, depending
4792 on IN_P) the range. Return 0 if the test couldn't be created. */
4794 tree
4797 {
4800 /* Disable this optimization for function pointer expressions
4801 on targets that require function pointer canonicalization. */
4808 {
4814 }
4836 value);
4839 {
4841 {
4845 }
4847 }
4849 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4851 {
4855 {
4857 {
4860 etype
4862 else
4865 }
4868 }
4869 }
4871 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4872 This requires wrap-around arithmetics for the type of the expression. */
4892 }
4893 \f
4894 /* Return the predecessor of VAL in its type, handling the infinite case. */
4896 static tree
4898 {
4904 else
4907 }
4909 /* Return the successor of VAL in its type, handling the infinite case. */
4911 static tree
4913 {
4919 else
4922 }
4924 /* Given two ranges, see if we can merge them into one. Return 1 if we
4925 can, 0 if we can't. Set the output range into the specified parameters. */
4927 bool
4930 {
4934 tree tem;
4944 /* Make range 0 be the range that starts first, or ends last if they
4945 start at the same value. Swap them if it isn't. */
4948 || (lowequal
4951 {
4955 }
4957 /* Now flag two cases, whether the ranges are disjoint or whether the
4958 second range is totally subsumed in the first. Note that the tests
4959 below are simplified by the ones above. */
4965 /* We now have four cases, depending on whether we are including or
4966 excluding the two ranges. */
4968 {
4969 /* If they don't overlap, the result is false. If the second range
4970 is a subset it is the result. Otherwise, the range is from the start
4971 of the second to the end of the first. */
4976 else
4978 }
4981 {
4982 /* If they don't overlap, the result is the first range. If they are
4983 equal, the result is false. If the second range is a subset of the
4984 first, and the ranges begin at the same place, we go from just after
4985 the end of the second range to the end of the first. If the second
4986 range is not a subset of the first, or if it is a subset and both
4987 ranges end at the same place, the range starts at the start of the
4988 first range and ends just before the second range.
4989 Otherwise, we can't describe this as a single range. */
4995 {
5000 {
5001 /* We are in the weird situation where high0 > high1 but
5002 high1 has no successor. Punt. */
5004 }
5005 }
5007 {
5012 {
5013 /* low0 < low1 but low1 has no predecessor. Punt. */
5015 }
5016 }
5017 else
5019 }
5022 {
5023 /* If they don't overlap, the result is the second range. If the second
5024 is a subset of the first, the result is false. Otherwise,
5025 the range starts just after the first range and ends at the
5026 end of the second. */
5031 else
5032 {
5037 {
5038 /* high1 > high0 but high0 has no successor. Punt. */
5040 }
5041 }
5042 }
5044 else
5045 {
5046 /* The case where we are excluding both ranges. Here the complex case
5047 is if they don't overlap. In that case, the only time we have a
5048 range is if they are adjacent. If the second is a subset of the
5049 first, the result is the first. Otherwise, the range to exclude
5050 starts at the beginning of the first range and ends at the end of the
5051 second. */
5053 {
5058 else
5059 {
5060 /* Canonicalize - [min, x] into - [-, x]. */
5063 {
5068 /* FALLTHROUGH */
5081 }
5083 /* Canonicalize - [x, max] into - [x, -]. */
5086 {
5091 /* FALLTHROUGH */
5107 }
5109 /* The ranges might be also adjacent between the maximum and
5110 minimum values of the given type. For
5111 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5112 return + [x + 1, y - 1]. */
5114 {
5121 }
5122 else
5124 }
5125 }
5128 else
5130 }
5134 }
5135 \f
5137 /* Subroutine of fold, looking inside expressions of the form
5138 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5139 of the COND_EXPR. This function is being used also to optimize
5140 A op B ? C : A, by reversing the comparison first.
5142 Return a folded expression whose code is not a COND_EXPR
5143 anymore, or NULL_TREE if no folding opportunity is found. */
5145 static tree
5148 {
5153 tree tem;
5158 /* If we have A op 0 ? A : -A, consider applying the following
5159 transformations:
5161 A == 0? A : -A same as -A
5162 A != 0? A : -A same as A
5163 A >= 0? A : -A same as abs (A)
5164 A > 0? A : -A same as abs (A)
5165 A <= 0? A : -A same as -abs (A)
5166 A < 0? A : -A same as -abs (A)
5168 None of these transformations work for modes with signed
5169 zeros. If A is +/-0, the first two transformations will
5170 change the sign of the result (from +0 to -0, or vice
5171 versa). The last four will fix the sign of the result,
5172 even though the original expressions could be positive or
5173 negative, depending on the sign of A.
5175 Note that all these transformations are correct if A is
5176 NaN, since the two alternatives (A and -A) are also NaNs. */
5183 /* In the case that A is of the form X-Y, '-A' (arg2) may
5184 have already been folded to Y-X, check for that. */
5192 {
5204 /* Fall through. */
5215 /* FALLTHRU */
5225 }
5227 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5228 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5229 both transformations are correct when A is NaN: A != 0
5230 is then true, and A == 0 is false. */
5234 {
5239 }
5241 /* Try some transformations of A op B ? A : B.
5243 A == B? A : B same as B
5244 A != B? A : B same as A
5245 A >= B? A : B same as max (A, B)
5246 A > B? A : B same as max (B, A)
5247 A <= B? A : B same as min (A, B)
5248 A < B? A : B same as min (B, A)
5250 As above, these transformations don't work in the presence
5251 of signed zeros. For example, if A and B are zeros of
5252 opposite sign, the first two transformations will change
5253 the sign of the result. In the last four, the original
5254 expressions give different results for (A=+0, B=-0) and
5255 (A=-0, B=+0), but the transformed expressions do not.
5257 The first two transformations are correct if either A or B
5258 is a NaN. In the first transformation, the condition will
5259 be false, and B will indeed be chosen. In the case of the
5260 second transformation, the condition A != B will be true,
5261 and A will be chosen.
5263 The conversions to max() and min() are not correct if B is
5264 a number and A is not. The conditions in the original
5265 expressions will be false, so all four give B. The min()
5266 and max() versions would give a NaN instead. */
5269 /* Avoid these transformations if the COND_EXPR may be used
5270 as an lvalue in the C++ front-end. PR c++/19199. */
5271 && (in_gimple_form
5277 {
5283 {
5292 /* In C++ a ?: expression can be an lvalue, so put the
5293 operand which will be used if they are equal first
5294 so that we can convert this back to the
5295 corresponding COND_EXPR. */
5297 {
5305 }
5312 {
5320 }
5333 }
5334 }
5337 }
5340 \f
5341 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5342 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5343 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5344 false) >= 2)
5345 #endif
5347 /* EXP is some logical combination of boolean tests. See if we can
5348 merge it into some range test. Return the new tree if so. */
5350 static tree
5353 {
5369 /* If this is an OR operation, invert both sides; we will invert
5370 again at the end. */
5374 /* If both expressions are the same, if we can merge the ranges, and we
5375 can build the range test, return it or it inverted. If one of the
5376 ranges is always true or always false, consider it to be the same
5377 expression as the other. */
5385 {
5389 }
5391 /* On machines where the branch cost is expensive, if this is a
5392 short-circuited branch and the underlying object on both sides
5393 is the same, make a non-short-circuit operation. */
5395 && !flag_sanitize_coverage
5400 {
5401 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5402 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5403 which cases we can't do this. */
5411 {
5420 {
5423 WARN_STRICT_OVERFLOW_COMPARISON);
5427 }
5428 }
5429 }
5432 }
5433 \f
5434 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5435 bit value. Arrange things so the extra bits will be set to zero if and
5436 only if C is signed-extended to its full width. If MASK is nonzero,
5437 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5439 static tree
5441 {
5444 tree temp;
5449 /* We work by getting just the sign bit into the low-order bit, then
5450 into the high-order bit, then sign-extend. We then XOR that value
5451 with C. */
5454 /* We must use a signed type in order to get an arithmetic right shift.
5455 However, we must also avoid introducing accidental overflows, so that
5456 a subsequent call to integer_zerop will work. Hence we must
5457 do the type conversion here. At this point, the constant is either
5458 zero or one, and the conversion to a signed type can never overflow.
5459 We could get an overflow if this conversion is done anywhere else. */
5468 /* If necessary, convert the type back to match the type of C. */
5473 }
5474 \f
5475 /* For an expression that has the form
5476 (A && B) || ~B
5477 or
5478 (A || B) && ~B,
5479 we can drop one of the inner expressions and simplify to
5480 A || ~B
5481 or
5482 A && ~B
5483 LOC is the location of the resulting expression. OP is the inner
5484 logical operation; the left-hand side in the examples above, while CMPOP
5485 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5486 removing a condition that guards another, as in
5487 (A != NULL && A->...) || A == NULL
5488 which we must not transform. If RHS_ONLY is true, only eliminate the
5489 right-most operand of the inner logical operation. */
5491 static tree
5494 {
5512 {
5515 {
5518 }
5519 }
5521 {
5524 {
5527 }
5528 }
5543 }
5545 /* Find ways of folding logical expressions of LHS and RHS:
5546 Try to merge two comparisons to the same innermost item.
5547 Look for range tests like "ch >= '0' && ch <= '9'".
5548 Look for combinations of simple terms on machines with expensive branches
5549 and evaluate the RHS unconditionally.
5551 For example, if we have p->a == 2 && p->b == 4 and we can make an
5552 object large enough to span both A and B, we can do this with a comparison
5553 against the object ANDed with the a mask.
5555 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5556 operations to do this with one comparison.
5558 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5559 function and the one above.
5561 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5562 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5564 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5565 two operands.
5567 We return the simplified tree or 0 if no optimization is possible. */
5569 static tree
5572 {
5573 /* If this is the "or" of two comparisons, we can do something if
5574 the comparisons are NE_EXPR. If this is the "and", we can do something
5575 if the comparisons are EQ_EXPR. I.e.,
5576 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5578 WANTED_CODE is this operation code. For single bit fields, we can
5579 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5580 comparison for one-bit fields. */
5601 /* Start by getting the comparison codes. Fail if anything is volatile.
5602 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5603 it were surrounded with a NE_EXPR. */
5612 {
5616 }
5619 {
5623 }
5634 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5637 {
5640 {
5645 }
5648 {
5654 }
5655 }
5660 /* If the RHS can be evaluated unconditionally and its operands are
5661 simple, it wins to evaluate the RHS unconditionally on machines
5662 with expensive branches. In this case, this isn't a comparison
5663 that can be merged. */
5670 {
5671 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5682 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5692 }
5694 /* See if the comparisons can be merged. Then get all the parameters for
5695 each side. */
5720 /* It must be true that the inner operation on the lhs of each
5721 comparison must be the same if we are to be able to do anything.
5722 Then see if we have constants. If not, the same must be true for
5723 the rhs's. */
5732 {
5735 }
5740 else
5743 /* If either comparison code is not correct for our logical operation,
5744 fail. However, we can convert a one-bit comparison against zero into
5745 the opposite comparison against that bit being set in the field. */
5749 {
5751 {
5752 /* Make the left operand unsigned, since we are only interested
5753 in the value of one bit. Otherwise we are doing the wrong
5754 thing below. */
5757 }
5758 else
5760 }
5762 /* This is analogous to the code for l_const above. */
5764 {
5766 {
5769 }
5770 else
5772 }
5774 /* See if we can find a mode that contains both fields being compared on
5775 the left. If we can't, fail. Otherwise, update all constants and masks
5776 to be relative to a field of that size. */
5790 {
5793 }
5801 {
5808 {
5812 }
5813 }
5815 {
5822 {
5826 }
5827 }
5829 /* If the right sides are not constant, do the same for it. Also,
5830 disallow this optimization if a size or signedness mismatch occurs
5831 between the left and right sides. */
5833 {
5836 /* Make sure the two fields on the right
5837 correspond to the left without being swapped. */
5854 {
5857 }
5866 /* Make a mask that corresponds to both fields being compared.
5867 Do this for both items being compared. If the operands are the
5868 same size and the bits being compared are in the same position
5869 then we can do this by masking both and comparing the masked
5870 results. */
5874 {
5888 }
5890 /* There is still another way we can do something: If both pairs of
5891 fields being compared are adjacent, we may be able to make a wider
5892 field containing them both.
5894 Note that we still must mask the lhs/rhs expressions. Furthermore,
5895 the mask must be shifted to account for the shift done by
5896 make_bit_field_ref. */
5901 {
5902 tree type;
5918 /* Convert to the smaller type before masking out unwanted bits. */
5921 {
5923 {
5927 }
5929 {
5933 }
5934 }
5943 }
5946 }
5948 /* Handle the case of comparisons with constants. If there is something in
5949 common between the masks, those bits of the constants must be the same.
5950 If not, the condition is always false. Test for this to avoid generating
5951 incorrect code below. */
5956 {
5958 {
5961 }
5962 else
5963 {
5966 }
5967 }
5969 /* Construct the expression we will return. First get the component
5970 reference we will make. Unless the mask is all ones the width of
5971 that field, perform the mask operation. Then compare with the
5972 merged constant. */
5983 }
5984 \f
5985 /* T is an integer expression that is being multiplied, divided, or taken a
5986 modulus (CODE says which and what kind of divide or modulus) by a
5987 constant C. See if we can eliminate that operation by folding it with
5988 other operations already in T. WIDE_TYPE, if non-null, is a type that
5989 should be used for the computation if wider than our type.
5991 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5992 (X * 2) + (Y * 4). We must, however, be assured that either the original
5993 expression would not overflow or that overflow is undefined for the type
5994 in the language in question.
5996 If we return a non-null expression, it is an equivalent form of the
5997 original computation, but need not be in the original type.
5999 We set *STRICT_OVERFLOW_P to true if the return values depends on
6000 signed overflow being undefined. Otherwise we do not change
6001 *STRICT_OVERFLOW_P. */
6003 static tree
6006 {
6007 /* To avoid exponential search depth, refuse to allow recursion past
6008 three levels. Beyond that (1) it's highly unlikely that we'll find
6009 something interesting and (2) we've probably processed it before
6010 when we built the inner expression. */
6013 tree ret;
6018 depth++;
6020 depth--;
6023 }
6025 static tree
6028 {
6040 /* Don't deal with constants of zero here; they confuse the code below. */
6050 /* Note that we need not handle conditional operations here since fold
6051 already handles those cases. So just do arithmetic here. */
6053 {
6055 /* For a constant, we can always simplify if we are a multiply
6056 or (for divide and modulus) if it is a multiple of our constant. */
6059 {
6062 /* If the multiplication overflowed, we lost information on it.
6063 See PR68142 and PR69845. */
6067 }
6071 /* If op0 is an expression ... */
6077 /* ... and has wrapping overflow, and its type is smaller
6078 than ctype, then we cannot pass through as widening. */
6083 /* ... or this is a truncation (t is narrower than op0),
6084 then we cannot pass through this narrowing. */
6087 /* ... or signedness changes for division or modulus,
6088 then we cannot pass through this conversion. */
6092 /* ... or has undefined overflow while the converted to
6093 type has not, we cannot do the operation in the inner type
6094 as that would introduce undefined overflow. */
6100 /* Pass the constant down and see if we can make a simplification. If
6101 we can, replace this expression with the inner simplification for
6102 possible later conversion to our or some other type. */
6107 code == MULT_EXPR
6109 strict_overflow_p))))
6114 /* If widening the type changes it from signed to unsigned, then we
6115 must avoid building ABS_EXPR itself as unsigned. */
6117 {
6121 {
6124 }
6126 }
6127 /* If the constant is negative, we cannot simplify this. */
6130 /* FALLTHROUGH */
6132 /* For division and modulus, type can't be unsigned, as e.g.
6133 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6134 For signed types, even with wrapping overflow, this is fine. */
6143 /* If widening the type changes the signedness, then we can't perform
6144 this optimization as that changes the result. */
6148 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6154 {
6161 }
6165 /* If the second operand is constant, this is a multiplication
6166 or floor division, by a power of two, so we can treat it that
6167 way unless the multiplier or divisor overflows. Signed
6168 left-shift overflow is implementation-defined rather than
6169 undefined in C90, so do not convert signed left shift into
6170 multiplication. */
6173 /* const_binop may not detect overflow correctly,
6174 so check for it explicitly here. */
6178 size_one_node,
6179 op1)))
6183 ctype,
6185 t1),
6190 /* See if we can eliminate the operation on both sides. If we can, we
6191 can return a new PLUS or MINUS. If we can't, the only remaining
6192 cases where we can do anything are if the second operand is a
6193 constant. */
6200 /* If not multiplication, we can only do this if both operands
6201 are divisible by c. */
6204 {
6209 }
6211 /* If this was a subtraction, negate OP1 and set it to be an addition.
6212 This simplifies the logic below. */
6214 {
6216 /* If OP1 was not easily negatable, the constant may be OP0. */
6218 {
6221 }
6222 }
6227 /* If either OP1 or C are negative, this optimization is not safe for
6228 some of the division and remainder types while for others we need
6229 to change the code. */
6231 {
6239 }
6241 /* If it's a multiply or a division/modulus operation of a multiple
6242 of our constant, do the operation and verify it doesn't overflow. */
6245 {
6248 /* We allow the constant to overflow with wrapping semantics. */
6252 }
6253 else
6256 /* If we have an unsigned type, we cannot widen the operation since it
6257 will change the result if the original computation overflowed. */
6261 /* The last case is if we are a multiply. In that case, we can
6262 apply the distributive law to commute the multiply and addition
6263 if the multiplication of the constants doesn't overflow
6264 and overflow is defined. With undefined overflow
6265 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6271 op1);
6276 /* We have a special case here if we are doing something like
6277 (C * 8) % 4 since we know that's zero. */
6280 /* If the multiplication can overflow we cannot optimize this. */
6284 {
6287 }
6289 /* ... fall through ... */
6293 /* If we can extract our operation from the LHS, do so and return a
6294 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6295 do something only if the second operand is a constant. */
6311 /* If these are the same operation types, we can associate them
6312 assuming no overflow. */
6314 {
6329 }
6331 /* If these operations "cancel" each other, we have the main
6332 optimizations of this pass, which occur when either constant is a
6333 multiple of the other, in which case we replace this with either an
6334 operation or CODE or TCODE.
6336 If we have an unsigned type, we cannot do this since it will change
6337 the result if the original computation overflowed. */
6344 {
6346 {
6353 }
6355 {
6362 }
6363 }
6368 }
6371 }
6372 \f
6373 /* Return a node which has the indicated constant VALUE (either 0 or
6374 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6375 and is of the indicated TYPE. */
6377 tree
6379 {
6388 else
6390 }
6393 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6394 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6395 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6396 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6397 COND is the first argument to CODE; otherwise (as in the example
6398 given here), it is the second argument. TYPE is the type of the
6399 original expression. Return NULL_TREE if no simplification is
6400 possible. */
6402 static tree
6407 {
6417 {
6421 /* If this operand throws an expression, then it does not make
6422 sense to try to perform a logical or arithmetic operation
6423 involving it. */
6428 }
6431 {
6436 }
6437 else
6438 /* Detect the case of mixing vector and scalar types - bail out. */
6444 /* This transformation is only worthwhile if we don't have to wrap ARG
6445 in a SAVE_EXPR and the operation can be simplified without recursing
6446 on at least one of the branches once its pushed inside the COND_EXPR. */
6455 {
6459 else
6461 }
6463 {
6467 else
6469 }
6471 /* Check that we have simplified at least one of the branches. */
6476 }
6478 \f
6479 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6481 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6482 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6483 ADDEND is the same as X.
6485 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6486 and finite. The problematic cases are when X is zero, and its mode
6487 has signed zeros. In the case of rounding towards -infinity,
6488 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6489 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6491 bool
6493 {
6497 /* Don't allow the fold with -fsignaling-nans. */
6501 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6505 /* In a vector or complex, we would need to check the sign of all zeros. */
6509 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6513 /* The mode has signed zeros, and we have to honor their sign.
6514 In this situation, there is only one case we can return true for.
6515 X - 0 is the same as X unless rounding towards -infinity is
6516 supported. */
6518 }
6520 /* Subroutine of match.pd that optimizes comparisons of a division by
6521 a nonzero integer constant against an integer constant, i.e.
6522 X/C1 op C2.
6524 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6525 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6527 enum tree_code
6530 {
6535 /* We have to do this the hard way to detect unsigned overflow.
6536 prod = int_const_binop (MULT_EXPR, c1, c2); */
6542 {
6546 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6549 }
6551 {
6554 {
6573 }
6574 }
6575 else
6576 {
6577 /* A negative divisor reverses the relational operators. */
6582 {
6601 }
6602 }
6615 }
6618 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6619 equality/inequality test, then return a simplified form of the test
6620 using a sign testing. Otherwise return NULL. TYPE is the desired
6621 result type. */
6623 static tree
6626 tree result_type)
6627 {
6628 /* If this is testing a single bit, we can optimize the test. */
6632 {
6633 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6634 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6638 /* This is only a win if casting to a signed type is cheap,
6639 i.e. when arg00's type is not a partial mode. */
6641 {
6644 result_type,
6647 }
6648 }
6651 }
6653 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6654 equality/inequality test, then return a simplified form of
6655 the test using shifts and logical operations. Otherwise return
6656 NULL. TYPE is the desired result type. */
6658 tree
6661 {
6662 /* If this is testing a single bit, we can optimize the test. */
6666 {
6675 /* First, see if we can fold the single bit test into a sign-bit
6676 test. */
6678 result_type);
6682 /* Otherwise we have (A & C) != 0 where C is a single bit,
6683 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6684 Similarly for (A & C) == 0. */
6686 /* If INNER is a right shift of a constant and it plus BITNUM does
6687 not overflow, adjust BITNUM and INNER. */
6693 {
6696 }
6698 /* If we are going to be able to omit the AND below, we must do our
6699 operations as unsigned. If we must use the AND, we have a choice.
6700 Normally unsigned is faster, but for some machines signed is. */
6718 /* Put the AND last so it can combine with more things. */
6721 /* Make sure to return the proper type. */
6725 }
6727 }
6729 /* Test whether it is preferable two swap two operands, ARG0 and
6730 ARG1, for example because ARG0 is an integer constant and ARG1
6731 isn't. */
6733 bool
6735 {
6749 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6750 for commutative and comparison operators. Ensuring a canonical
6751 form allows the optimizers to find additional redundancies without
6752 having to explicitly check for both orderings. */
6758 /* Put SSA_NAMEs last. */
6764 /* Put variables last. */
6771 }
6774 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6775 means A >= Y && A != MAX, but in this case we know that
6776 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6778 static tree
6780 {
6787 else
6796 {
6799 }
6801 {
6804 }
6805 else
6812 {
6813 /* Convert the pointer types into integer before taking the difference. */
6817 }
6818 else
6825 }
6827 /* Fold a sum or difference of at least one multiplication.
6828 Returns the folded tree or NULL if no simplification could be made. */
6830 static tree
6833 {
6837 /* (A * C) +- (B * C) -> (A+-B) * C.
6838 (A * C) +- A -> A * (C+-1).
6839 We are most concerned about the case where C is a constant,
6840 but other combinations show up during loop reduction. Since
6841 it is not difficult, try all four possibilities. */
6844 {
6847 }
6849 {
6852 }
6853 else
6854 {
6855 /* We cannot generate constant 1 for fract. */
6860 }
6862 {
6865 }
6867 {
6869 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6870 the purpose of this canonicalization. */
6874 {
6877 }
6878 else
6880 }
6881 else
6882 {
6883 /* We cannot generate constant 1 for fract. */
6888 }
6891 /* Prefer factoring a common non-constant. */
6901 /* No identical multiplicands; see if we can find a common
6902 power-of-two factor in non-power-of-two multiplies. This
6903 can help in multi-dimensional array access. */
6906 {
6909 tree maybe_same;
6913 /* Move min of absolute values to int11. */
6915 {
6920 }
6921 else
6925 /* The remainder should not be a constant, otherwise we
6926 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6927 increased the number of multiplications necessary. */
6929 {
6937 }
6938 }
6945 /* We are neither factoring zero nor minus one. */
6953 /* Same may be zero and thus the operation 'code' may overflow. Likewise
6954 same may be minus one and thus the multiplication may overflow. Perform
6955 the operations in an unsigned type. */
6960 /* If the sum evaluated to a constant that is not -INF the multiplication
6961 cannot overflow. */
6970 }
6972 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6973 specified by EXPR into the buffer PTR of length LEN bytes.
6974 Return the number of bytes placed in the buffer, or zero
6975 upon failure. */
6977 static int
6979 {
6993 {
6995 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
6996 number of bytes. */
7000 {
7007 else
7009 }
7010 else
7015 }
7017 }
7020 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7021 specified by EXPR into the buffer PTR of length LEN bytes.
7022 Return the number of bytes placed in the buffer, or zero
7023 upon failure. */
7025 static int
7027 {
7031 FIXED_VALUE_TYPE value;
7047 }
7050 /* Subroutine of native_encode_expr. Encode the REAL_CST
7051 specified by EXPR into the buffer PTR of length LEN bytes.
7052 Return the number of bytes placed in the buffer, or zero
7053 upon failure. */
7055 static int
7057 {
7063 /* There are always 32 bits in each long, no matter the size of
7064 the hosts long. We handle floating point representations with
7065 up to 192 bits. */
7079 {
7084 {
7091 else
7093 }
7094 else
7095 {
7098 {
7099 /* Reverse bytes within each long, or within the entire float
7100 if it's smaller than a long (for HFmode). */
7103 }
7104 }
7109 }
7111 }
7113 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7114 specified by EXPR into the buffer PTR of length LEN bytes.
7115 Return the number of bytes placed in the buffer, or zero
7116 upon failure. */
7118 static int
7120 {
7122 tree part;
7137 }
7140 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7141 specified by EXPR into the buffer PTR of length LEN bytes.
7142 Return the number of bytes placed in the buffer, or zero
7143 upon failure. */
7145 static int
7147 {
7157 {
7159 {
7162 }
7173 }
7175 }
7178 /* Subroutine of native_encode_expr. Encode the STRING_CST
7179 specified by EXPR into the buffer PTR of length LEN bytes.
7180 Return the number of bytes placed in the buffer, or zero
7181 upon failure. */
7183 static int
7185 {
7196 {
7199 {
7202 }
7205 }
7206 else
7209 }
7212 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7213 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7214 buffer PTR of length LEN bytes. If OFF is not -1 then start
7215 the encoding at byte offset OFF and encode at most LEN bytes.
7216 Return the number of bytes placed in the buffer, or zero upon failure. */
7218 int
7220 {
7221 /* We don't support starting at negative offset and -1 is special. */
7226 {
7247 }
7248 }
7251 /* Subroutine of native_interpret_expr. Interpret the contents of
7252 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7253 If the buffer cannot be interpreted, return NULL_TREE. */
7255 static tree
7257 {
7267 }
7270 /* Subroutine of native_interpret_expr. Interpret the contents of
7271 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7272 If the buffer cannot be interpreted, return NULL_TREE. */
7274 static tree
7276 {
7279 double_int result;
7280 FIXED_VALUE_TYPE fixed_value;
7290 }
7293 /* Subroutine of native_interpret_expr. Interpret the contents of
7294 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7295 If the buffer cannot be interpreted, return NULL_TREE. */
7297 static tree
7299 {
7303 /* There are always 32 bits in each long, no matter the size of
7304 the hosts long. We handle floating point representations with
7305 up to 192 bits. */
7306 REAL_VALUE_TYPE r;
7316 {
7317 /* Both OFFSET and BYTE index within a long;
7318 bitpos indexes the whole float. */
7321 {
7328 else
7330 }
7331 else
7332 {
7335 {
7336 /* Reverse bytes within each long, or within the entire float
7337 if it's smaller than a long (for HFmode). */
7340 }
7341 }
7345 }
7349 }
7352 /* Subroutine of native_interpret_expr. Interpret the contents of
7353 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7354 If the buffer cannot be interpreted, return NULL_TREE. */
7356 static tree
7358 {
7373 }
7376 /* Subroutine of native_interpret_expr. Interpret the contents of
7377 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7378 If the buffer cannot be interpreted, return NULL_TREE. */
7380 static tree
7382 {
7394 {
7399 }
7401 }
7404 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7405 the buffer PTR of length LEN as a constant of type TYPE. For
7406 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7407 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7408 return NULL_TREE. */
7410 tree
7412 {
7414 {
7436 }
7437 }
7439 /* Returns true if we can interpret the contents of a native encoding
7440 as TYPE. */
7442 static bool
7444 {
7446 {
7459 }
7460 }
7462 /* Return true iff a constant of type TYPE is accepted by
7463 native_encode_expr. */
7465 bool
7467 {
7469 {
7479 }
7480 }
7482 /* Return true iff a STRING_CST S is accepted by
7483 native_encode_expr. */
7485 bool
7487 {
7490 /* Wide-char strings are encoded in target byte-order so native
7491 encoding them is trivial. */
7498 }
7500 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7501 TYPE at compile-time. If we're unable to perform the conversion
7502 return NULL_TREE. */
7504 static tree
7506 {
7507 /* We support up to 512-bit values (for V8DFmode). */
7511 /* Check that the host and target are sane. */
7520 }
7522 /* Build an expression for the address of T. Folds away INDIRECT_REF
7523 to avoid confusing the gimplify process. */
7525 tree
7527 {
7528 /* The size of the object is not relevant when talking about its address. */
7533 {
7538 }
7548 {
7553 }
7554 else
7558 }
7560 /* Build an expression for the address of T. */
7562 tree
7564 {
7568 }
7570 /* Fold a unary expression of code CODE and type TYPE with operand
7571 OP0. Return the folded expression if folding is successful.
7572 Otherwise, return NULL_TREE. */
7574 tree
7576 {
7577 tree tem;
7578 tree arg0;
7586 {
7589 {
7590 /* Don't use STRIP_NOPS, because signedness of argument type
7591 matters. */
7593 }
7594 else
7595 {
7596 /* Strip any conversions that don't change the mode. This
7597 is safe for every expression, except for a comparison
7598 expression because its signedness is derived from its
7599 operands.
7601 Note that this is done as an internal manipulation within
7602 the constant folder, in order to find the simplest
7603 representation of the arguments so that their form can be
7604 studied. In any cases, the appropriate type conversions
7605 should be put back in the tree that will get out of the
7606 constant folder. */
7608 }
7611 {
7614 {
7618 }
7619 }
7620 }
7627 {
7634 {
7648 /* If this was a conversion, and all we did was to move into
7649 inside the COND_EXPR, bring it back out. But leave it if
7650 it is a conversion from integer to integer and the
7651 result precision is no wider than a word since such a
7652 conversion is cheap and may be optimized away by combine,
7653 while it couldn't if it were outside the COND_EXPR. Then return
7654 so we don't get into an infinite recursion loop taking the
7655 conversion out and then back in. */
7667 && (INTEGRAL_TYPE_P
7680 }
7681 }
7684 {
7690 CASE_CONVERT:
7694 {
7695 /* If we have (type) (a CMP b) and type is an integral type, return
7696 new expression involving the new type. Canonicalize
7697 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7698 non-integral type.
7699 Do not fold the result as that would not simplify further, also
7700 folding again results in recursions. */
7710 }
7712 /* Handle (T *)&A.B.C for A being of type T and B and C
7713 living at offset zero. This occurs frequently in
7714 C++ upcasting and then accessing the base. */
7718 {
7720 tree offset;
7721 machine_mode mode;
7723 tree base
7727 /* If the reference was to a (constant) zero offset, we can use
7728 the address of the base if it has the same base type
7729 as the result type and the pointer type is unqualified. */
7736 }
7740 /* Detect assigning a bitfield. */
7742 && DECL_BIT_FIELD
7744 {
7745 /* Don't leave an assignment inside a conversion
7746 unless assigning a bitfield. */
7748 /* First do the assignment, then return converted constant. */
7753 }
7755 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7756 constants (if x has signed type, the sign bit cannot be set
7757 in c). This folds extension into the BIT_AND_EXPR.
7758 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7759 very likely don't have maximal range for their precision and this
7760 transformation effectively doesn't preserve non-maximal ranges. */
7764 {
7775 <= HOST_BITS_PER_WIDE_INT
7777 {
7781 cst &= HOST_WIDE_INT_M1U
7785 && !flag_syntax_only
7788 {
7792 }
7793 }
7795 {
7800 }
7801 }
7803 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7804 cast (T1)X will fold away. We assume that this happens when X itself
7805 is a cast. */
7809 {
7813 return fold_build_pointer_plus_loc
7815 }
7817 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7818 of the same precision, and X is an integer type not narrower than
7819 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7825 {
7831 }
7833 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7834 type of X and Y (integer types only). */
7839 {
7840 /* Be careful not to introduce new overflows. */
7841 tree mult_type;
7844 else
7848 {
7855 }
7856 }
7862 {
7869 }
7880 /* Convert fabs((double)float) into (double)fabsf(float). */
7883 {
7889 targ0));
7890 }
7894 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7913 /* Note that the operand of this must be an int
7914 and its values must be 0 or 1.
7915 ("true" is a fixed value perhaps depending on the language,
7916 but we don't handle values other than 1 correctly yet.) */
7923 /* Fold *&X to X if X is an lvalue. */
7925 {
7932 }
7938 }
7941 /* If the operation was a conversion do _not_ mark a resulting constant
7942 with TREE_OVERFLOW if the original constant was not. These conversions
7943 have implementation defined behavior and retaining the TREE_OVERFLOW
7944 flag here would confuse later passes such as VRP. */
7945 tree
7948 {
7957 }
7959 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7960 operands OP0 and OP1. LOC is the location of the resulting expression.
7961 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7962 Return the folded expression if folding is successful. Otherwise,
7963 return NULL_TREE. */
7964 static tree
7967 {
7968 tree tem;
7970 /* We only do these simplifications if we are optimizing. */
7974 /* Check for things like (A || B) && (A || C). We can convert this
7975 to A || (B && C). Note that either operator can be any of the four
7976 truth and/or operations and the transformation will still be
7977 valid. Also note that we only care about order for the
7978 ANDIF and ORIF operators. If B contains side effects, this
7979 might change the truth-value of A. */
7986 {
8006 /* This case if tricky because we must either have commutative
8007 operators or else A10 must not have side-effects. */
8013 a01);
8014 }
8016 /* See if we can build a range comparison. */
8022 {
8026 }
8030 {
8034 }
8036 /* Check for the possibility of merging component references. If our
8037 lhs is another similar operation, try to merge its rhs with our
8038 rhs. Then try to merge our lhs and rhs. */
8048 && !flag_sanitize_coverage
8053 {
8060 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8061 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8062 We don't want to pack more than two leafs to a non-IF AND/OR
8063 expression.
8064 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8065 equal to IF-CODE, then we don't want to add right-hand operand.
8066 If the inner right-hand side of left-hand operand has
8067 side-effects, or isn't simple, then we can't add to it,
8068 as otherwise we might destroy if-sequence. */
8071 /* Needed for sequence points to handle trappings, and
8072 side-effects. */
8074 {
8076 arg1);
8078 tem);
8079 }
8080 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8081 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8084 /* Needed for sequence points to handle trappings, and
8085 side-effects. */
8087 {
8092 }
8093 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8094 into (A OR B).
8095 For sequence point consistancy, we need to check for trapping,
8096 and side-effects. */
8100 }
8103 }
8105 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8106 by changing CODE to reduce the magnitude of constants involved in
8107 ARG0 of the comparison.
8108 Returns a canonicalized comparison tree if a simplification was
8109 possible, otherwise returns NULL_TREE.
8110 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8111 valid if signed overflow is undefined. */
8113 static tree
8117 {
8122 /* Match A +- CST code arg1. We can change this only if overflow
8123 is undefined. */
8126 /* In principle pointers also have undefined overflow behavior,
8127 but that causes problems elsewhere. */
8134 /* Identify the constant in arg0 and its sign. */
8138 /* Overflowed constants and zero will cause problems. */
8143 /* See if we can reduce the magnitude of the constant in
8144 arg0 by changing the comparison code. */
8145 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8149 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8153 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8157 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8161 else
8165 /* Now build the constant reduced in magnitude. But not if that
8166 would produce one outside of its types range. */
8182 }
8184 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8185 overflow further. Try to decrease the magnitude of constants involved
8186 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8187 and put sole constants at the second argument position.
8188 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8190 static tree
8193 {
8194 tree t;
8199 /* Try canonicalization by simplifying arg0. */
8204 {
8208 }
8210 /* Try canonicalization by simplifying arg1 using the swapped
8211 comparison. */
8219 }
8221 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8222 space. This is used to avoid issuing overflow warnings for
8223 expressions like &p->x which can not wrap. */
8225 static bool
8227 {
8234 wide_int wi_offset;
8240 else
8256 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8257 array. */
8259 {
8260 HOST_WIDE_INT base_size;
8265 }
8268 }
8270 /* Return a positive integer when the symbol DECL is known to have
8271 a nonzero address, zero when it's known not to (e.g., it's a weak
8272 symbol), and a negative integer when the symbol is not yet in the
8273 symbol table and so whether or not its address is zero is unknown.
8274 For function local objects always return positive integer. */
8275 static int
8277 {
8282 /* Function local objects are never NULL. */
8290 }
8292 /* Subroutine of fold_binary. This routine performs all of the
8293 transformations that are common to the equality/inequality
8294 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8295 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8296 fold_binary should call fold_binary. Fold a comparison with
8297 tree code CODE and type TYPE with operands OP0 and OP1. Return
8298 the folded comparison or NULL_TREE. */
8300 static tree
8303 {
8313 /* For comparisons of pointers we can decompose it to a compile time
8314 comparison of the base objects and the offsets into the object.
8315 This requires at least one operand being an ADDR_EXPR or a
8316 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8322 {
8325 machine_mode mode;
8329 /* Get base and offset for the access. Strip ADDR_EXPR for
8330 get_inner_reference, but put it back by stripping INDIRECT_REF
8331 off the base object if possible. indirect_baseN will be true
8332 if baseN is not an address but refers to the object itself. */
8335 {
8336 base0
8342 else
8344 }
8346 {
8350 {
8351 base0
8357 else
8359 }
8362 else
8366 {
8372 {
8375 }
8376 }
8377 }
8381 {
8382 base1
8388 else
8390 }
8392 {
8396 {
8397 base1
8403 else
8405 }
8408 else
8412 {
8418 {
8421 }
8422 }
8423 }
8425 /* If we have equivalent bases we might be able to simplify. */
8429 {
8430 /* We can fold this expression to a constant if the non-constant
8431 offset parts are equal. */
8435 {
8441 "occur when comparing P +- C1 with "
8443 WARN_STRICT_OVERFLOW_CONDITIONAL);
8446 {
8460 }
8461 }
8462 /* We can simplify the comparison to a comparison of the variable
8463 offset parts if the constant offset parts are equal.
8464 Be careful to use signed sizetype here because otherwise we
8465 mess with array offsets in the wrong way. This is possible
8466 because pointer arithmetic is restricted to retain within an
8467 object and overflow on pointer differences is undefined as of
8468 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8470 {
8471 /* By converting to signed sizetype we cover middle-end pointer
8472 arithmetic which operates on unsigned pointer types of size
8473 type size and ARRAY_REF offsets which are properly sign or
8474 zero extended from their type in case it is narrower than
8475 sizetype. */
8478 else
8482 else
8489 "occur when comparing P +- C1 with "
8491 WARN_STRICT_OVERFLOW_COMPARISON);
8494 }
8495 }
8496 /* For equal offsets we can simplify to a comparison of the
8497 base addresses. */
8499 && (indirect_base0
8501 && (indirect_base1
8506 {
8512 }
8513 /* Comparison between an ordinary (non-weak) symbol and a null
8514 pointer can be eliminated since such symbols must have a non
8515 null address. In C, relational expressions between pointers
8516 to objects and null pointers are undefined. The results
8517 below follow the C++ rules with the additional property that
8518 every object pointer compares greater than a null pointer.
8519 */
8522 /* Avoid folding references to struct members at offset 0 to
8523 prevent tests like '&ptr->firstmember == 0' from getting
8524 eliminated. When ptr is null, although the -> expression
8525 is strictly speaking invalid, GCC retains it as a matter
8526 of QoI. See PR c/44555. */
8529 && indirect_base0
8530 /* The caller guarantees that when one of the arguments is
8531 constant (i.e., null in this case) it is second. */
8533 {
8535 {
8546 }
8547 }
8548 }
8550 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8551 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8552 the resulting offset is smaller in absolute value than the
8553 original one and has the same sign. */
8562 {
8567 tree cst;
8569 "occur when combining constants around "
8572 /* Put the constant on the side where it doesn't overflow and is
8573 of lower absolute value and of same sign than before. */
8580 {
8583 variable1,
8587 }
8595 {
8601 variable2);
8602 }
8603 }
8609 /* If we are comparing an expression that just has comparisons
8610 of two integer values, arithmetic expressions of those comparisons,
8611 and constants, we can simplify it. There are only three cases
8612 to check: the two values can either be equal, the first can be
8613 greater, or the second can be greater. Fold the expression for
8614 those three values. Since each value must be 0 or 1, we have
8615 eight possibilities, each of which corresponds to the constant 0
8616 or 1 or one of the six possible comparisons.
8618 This handles common cases like (a > b) == 0 but also handles
8619 expressions like ((x > y) - (y > x)) > 0, which supposedly
8620 occur in macroized code. */
8623 {
8628 /* Don't handle degenerate cases here; they should already
8629 have been handled anyway. */
8638 {
8642 /* We can't just pass T to eval_subst in case cval1 or cval2
8643 was the same as ARG1. */
8645 tree high_result
8649 arg1);
8650 tree equal_result
8654 arg1);
8655 tree low_result
8659 arg1);
8661 /* All three of these results should be 0 or 1. Confirm they are.
8662 Then use those values to select the proper code to use. */
8667 {
8668 /* Make a 3-bit mask with the high-order bit being the
8669 value for `>', the next for '=', and the low for '<'. */
8673 {
8675 /* Always false. */
8696 /* Always true. */
8698 }
8701 {
8705 }
8707 }
8708 }
8709 }
8712 }
8715 /* Subroutine of fold_binary. Optimize complex multiplications of the
8716 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8717 argument EXPR represents the expression "z" of type TYPE. */
8719 static tree
8721 {
8726 {
8729 }
8731 {
8734 }
8735 else
8736 {
8740 }
8749 }
8752 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8753 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8754 true if successful. */
8756 static bool
8758 {
8762 {
8765 }
8767 {
8773 else
8775 }
8776 else
8782 }
8784 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8785 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8786 NULL_TREE otherwise. */
8788 static tree
8790 {
8809 {
8813 }
8816 {
8822 }
8823 else
8825 }
8827 /* Try to fold a pointer difference of type TYPE two address expressions of
8828 array references AREF0 and AREF1 using location LOC. Return a
8829 simplified expression for the difference or NULL_TREE. */
8831 static tree
8834 {
8839 /* If the bases are array references as well, recurse. If the bases
8840 are pointer indirections compute the difference of the pointers.
8841 If the bases are equal, we are set. */
8844 && (base_offset
8848 && (base_offset
8854 {
8860 base_offset,
8863 }
8865 }
8867 /* If the real or vector real constant CST of type TYPE has an exact
8868 inverse, return it, else return NULL. */
8870 tree
8872 {
8873 REAL_VALUE_TYPE r;
8874 tree unit_type;
8875 machine_mode mode;
8879 {
8889 {
8896 {
8901 }
8904 }
8908 }
8909 }
8911 /* Mask out the tz least significant bits of X of type TYPE where
8912 tz is the number of trailing zeroes in Y. */
8913 static wide_int
8915 {
8920 }
8922 /* Return true when T is an address and is known to be nonzero.
8923 For floating point we further ensure that T is not denormal.
8924 Similar logic is present in nonzero_address in rtlanal.h.
8926 If the return value is based on the assumption that signed overflow
8927 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8928 change *STRICT_OVERFLOW_P. */
8930 static bool
8932 {
8936 /* Doing something useful for floating point would need more work. */
8942 {
8945 strict_overflow_p);
8951 strict_overflow_p);
8959 }
8962 {
8965 strict_overflow_p);
8973 strict_overflow_p);
8988 strict_overflow_p);
8992 strict_overflow_p);
8995 {
9007 }
9011 }
9013 }
9015 /* Return true when T is an address and is known to be nonzero.
9016 Handle warnings about undefined signed overflow. */
9018 bool
9020 {
9027 "determining that expression is always "
9029 WARN_STRICT_OVERFLOW_MISC);
9031 }
9033 /* Return true if T is known not to be equal to an integer W. */
9035 bool
9037 {
9039 value_range_type rtype;
9041 {
9050 {
9055 }
9060 /* If T has some known zero bits and W has any of those bits set,
9061 then T is known not to be equal to W. */
9069 }
9070 }
9072 /* Fold a binary expression of code CODE and type TYPE with operands
9073 OP0 and OP1. LOC is the location of the resulting expression.
9074 Return the folded expression if folding is successful. Otherwise,
9075 return NULL_TREE. */
9077 tree
9080 {
9095 /* Strip any conversions that don't change the mode. This is
9096 safe for every expression, except for a comparison expression
9097 because its signedness is derived from its operands. So, in
9098 the latter case, only strip conversions that don't change the
9099 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9100 preserved.
9102 Note that this is done as an internal manipulation within the
9103 constant folder, in order to find the simplest representation
9104 of the arguments so that their form can be studied. In any
9105 cases, the appropriate type conversions should be put back in
9106 the tree that will get out of the constant folder. */
9109 {
9112 }
9113 else
9114 {
9117 }
9119 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9120 constant but we can't do arithmetic on them. */
9122 {
9125 {
9129 }
9130 }
9132 /* If this is a commutative operation, and ARG0 is a constant, move it
9133 to ARG1 to reduce the number of tests below. */
9138 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9139 to ARG1 to reduce the number of tests below. */
9148 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9150 First check for cases where an arithmetic operation is applied to a
9151 compound, conditional, or comparison operation. Push the arithmetic
9152 operation inside the compound or conditional to see if any folding
9153 can then be done. Convert comparison to conditional for this purpose.
9154 The also optimizes non-constant cases that used to be done in
9155 expand_expr.
9157 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9158 one of the operands is a comparison and the other is a comparison, a
9159 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9160 code below would make the expression more complex. Change it to a
9161 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9162 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9175 {
9179 boolean_type_node,
9187 }
9191 {
9193 {
9198 tem);
9199 }
9201 {
9206 tem);
9207 }
9212 {
9218 }
9223 {
9229 }
9230 }
9233 {
9235 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9238 {
9244 }
9246 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9249 {
9250 tree base;
9251 HOST_WIDE_INT coffset;
9260 }
9265 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9271 arg1),
9273 arg0)));
9279 {
9280 /* X + (X / CST) * -CST is X % CST. */
9285 {
9294 cst0));
9295 }
9296 }
9298 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9299 one. Make sure the type is not saturating and has the signedness of
9300 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9301 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9308 {
9312 }
9315 {
9316 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9317 (plus (plus (mult) (mult)) (foo)) so that we can
9318 take advantage of the factoring cases below. */
9327 {
9333 else
9346 parg0),
9348 marg)),
9352 return
9358 parg1)));
9359 }
9360 }
9361 else
9362 {
9363 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9364 to __complex__ ( x, y ). This is not the same for SNaNs or
9365 if signed zeros are involved. */
9369 {
9376 {
9380 {
9386 }
9388 {
9394 }
9395 }
9396 }
9404 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9405 We associate floats only if the user has specified
9406 -fassociative-math. */
9410 {
9415 {
9416 tree tree0;
9419 }
9420 }
9421 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9422 We associate floats only if the user has specified
9423 -fassociative-math. */
9427 {
9432 {
9433 tree tree0;
9436 }
9437 }
9438 }
9440 bit_rotate:
9441 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9442 is a rotate of A by C1 bits. */
9443 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9444 is a rotate of A by B bits. */
9445 {
9447 tree rtype;
9456 /* Only create rotates in complete modes. Other cases are not
9457 expanded properly. */
9460 {
9474 {
9478 code0 == LSHIFT_EXPR
9482 }
9484 {
9492 element_precision
9496 return
9499 ? LROTATE_EXPR
9504 }
9506 {
9514 element_precision
9518 return fold_convert_loc
9521 ? LROTATE_EXPR
9525 }
9526 }
9527 }
9529 associate:
9530 /* In most languages, can't associate operations on floats through
9531 parentheses. Rather than remember where the parentheses were, we
9532 don't associate floats at all, unless the user has specified
9533 -fassociative-math.
9534 And, we need to make sure type is not saturating. */
9538 {
9544 /* Split both trees into variables, constants, and literals. Then
9545 associate each group together, the constants with literals,
9546 then the result with variables. This increases the chances of
9547 literals being recombined later and of generating relocatable
9548 expressions for the sum of a constant and literal. */
9556 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9560 /* With undefined overflow prefer doing association in a type
9561 which wraps on overflow, if that is one of the operand types. */
9564 {
9572 }
9574 /* With undefined overflow we can only associate constants with one
9575 variable, and constants whose association doesn't overflow. */
9578 {
9580 {
9581 /* ??? If split_tree would handle NEGATE_EXPR we could
9582 simply reject these cases and the allowed cases would
9583 be the var0/minus_var1 ones. */
9589 {
9592 }
9599 {
9602 }
9608 /* The only case we can still associate with two variables
9609 is if they cancel out. */
9613 }
9619 }
9621 /* Only do something if we found more than two objects. Otherwise,
9622 nothing has changed and we risk infinite recursion. */
9630 {
9642 {
9646 }
9648 {
9652 }
9654 /* Preserve the MINUS_EXPR if the negative part of the literal is
9655 greater than the positive part. Otherwise, the multiplicative
9656 folding code (i.e extract_muldiv) may be fooled in case
9657 unsigned constants are subtracted, like in the following
9658 example: ((X*2 + 4) - 8U)/2. */
9660 {
9664 /* But avoid ending up with only negated parts. */
9666 {
9670 }
9671 else
9672 {
9676 }
9677 }
9679 /* Don't introduce overflows through reassociation. */
9684 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9691 /* Eliminate minus_con0. */
9693 {
9700 else
9703 }
9705 /* Eliminate minus_var0. */
9707 {
9711 else
9714 }
9716 return
9719 }
9720 }
9725 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9733 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9734 __complex__ ( x, -y ). This is not the same for SNaNs or if
9735 signed zeros are involved. */
9739 {
9746 {
9750 {
9752 arg1r ? arg1r
9757 }
9759 {
9763 arg1i ? arg1i
9766 }
9767 }
9768 }
9770 /* A - B -> A + (-B) if B is easily negatable. */
9774 /* Avoid this transformation if B is a positive REAL_CST. */
9782 /* Fold &a[i] - &a[j] to i-j. */
9787 {
9793 }
9796 && flag_unsafe_math_optimizations
9802 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9803 one. Make sure the type is not saturating and has the signedness of
9804 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9805 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9812 {
9816 }
9822 {
9823 /* Transform x * -C into -x * C if x is easily negatable. */
9838 {
9841 "occur when simplifying "
9843 WARN_STRICT_OVERFLOW_MISC);
9845 }
9847 /* Optimize z * conj(z) for integer complex numbers. */
9854 }
9855 else
9856 {
9857 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9858 This is not the same for NaNs or if signed zeros are
9859 involved. */
9865 {
9868 return
9874 return
9879 }
9881 /* Optimize z * conj(z) for floating point complex numbers.
9882 Guarded by flag_unsafe_math_optimizations as non-finite
9883 imaginary components don't produce scalar results. */
9892 }
9896 /* Canonicalize (X & C1) | C2. */
9900 {
9905 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9913 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9915 {
9918 }
9920 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9921 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9922 mode which allows further optimizations. */
9927 {
9931 {
9934 }
9935 }
9938 {
9943 }
9944 }
9946 /* See if this can be simplified into a rotate first. If that
9947 is unsuccessful continue in the association code. */
9951 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9959 /* See if this can be simplified into a rotate first. If that
9960 is unsuccessful continue in the association code. */
9964 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9969 {
9970 tree tem2;
9977 }
9978 /* Fold ~X & 1 as (X & 1) == 0. */
9982 {
9983 tree tem2;
9990 }
9991 /* Fold !X & 1 as X == 0. */
9994 {
9998 }
10000 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10001 multiple of 1 << CST. */
10003 {
10010 }
10012 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10013 bits from CST2. */
10017 {
10025 {
10026 /* Avoid the transform if arg1 is a mask of some
10027 mode which allows further optimizations. */
10034 }
10035 }
10037 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10038 ((A & N) + B) & M -> (A + B) & M
10039 Similarly if (N & M) == 0,
10040 ((A | N) + B) & M -> (A + B) & M
10041 and for - instead of + (or unary - instead of +)
10042 and/or ^ instead of |.
10043 If B is constant and (B & M) == 0, fold into A & M. */
10045 {
10054 {
10057 wide_int cst0;
10059 /* Now we know that arg0 is (C + D) or (C - D) or
10060 -C and arg1 (M) is == (1LL << cst) - 1.
10061 Store C into PMOP[0] and D into PMOP[1]. */
10065 {
10068 }
10075 {
10085 {
10088 }
10091 /* If C or D is of the form (A & N) where
10092 (N & M) == M, or of the form (A | N) or
10093 (A ^ N) where (N & M) == 0, replace it with A. */
10097 /* If C or D is a N where (N & M) == 0, it can be
10098 omitted (assumed 0). */
10106 }
10108 /* Only build anything new if we optimized one or both arguments
10109 above. */
10113 {
10116 {
10117 /* Perform the operations in a type that has defined
10118 overflow behavior. */
10124 }
10129 {
10137 else
10139 }
10142 else
10145 /* TEM is now the new binary +, - or unary - replacement. */
10149 }
10150 }
10151 }
10153 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10156 {
10161 return
10163 }
10168 /* Don't touch a floating-point divide by zero unless the mode
10169 of the constant can represent infinity. */
10175 /* (-A) / (-B) -> A / B */
10187 /* Fall through */
10190 /* Simplify A / (B << N) where A and B are positive and B is
10191 a power of 2, to A >> (N + log2(B)). */
10196 {
10199 {
10207 WARN_STRICT_OVERFLOW_MISC);
10213 }
10214 }
10216 /* Fall through */
10224 /* Convert -A / -B to A / B when the type is signed and overflow is
10225 undefined. */
10229 {
10232 "when distributing negation across "
10234 WARN_STRICT_OVERFLOW_MISC);
10239 }
10243 {
10246 "when distributing negation across "
10248 WARN_STRICT_OVERFLOW_MISC);
10253 }
10255 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10256 operation, EXACT_DIV_EXPR.
10258 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10259 At one time others generated faster code, it's not clear if they do
10260 after the last round to changes to the DIV code in expmed.c. */
10271 {
10275 WARN_STRICT_OVERFLOW_MISC);
10277 }
10289 {
10293 WARN_STRICT_OVERFLOW_MISC);
10295 }
10303 /* Since negative shift count is not well-defined,
10304 don't try to compute it in the compiler. */
10310 /* If we have a rotate of a bit operation with the rotate count and
10311 the second operand of the bit operation both constant,
10312 permute the two operations. */
10318 {
10326 }
10328 /* Two consecutive rotates adding up to the some integer
10329 multiple of the precision of the type can be ignored. */
10344 /* Note that the operands of this must be ints
10345 and their values must be 0 or 1.
10346 ("true" is a fixed value perhaps depending on the language.) */
10347 /* If first arg is constant zero, return it. */
10350 /* FALLTHRU */
10352 /* If either arg is constant true, drop it. */
10356 /* Preserve sequence points. */
10359 /* If second arg is constant zero, result is zero, but first arg
10360 must be evaluated. */
10363 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10364 case will be handled here. */
10368 /* !X && X is always false. */
10372 /* X && !X is always false. */
10377 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10378 means A >= Y && A != MAX, but in this case we know that
10379 A < X <= MAX. */
10383 {
10391 }
10400 /* Note that the operands of this must be ints
10401 and their values must be 0 or true.
10402 ("true" is a fixed value perhaps depending on the language.) */
10403 /* If first arg is constant true, return it. */
10406 /* FALLTHRU */
10408 /* If either arg is constant zero, drop it. */
10412 /* Preserve sequence points. */
10415 /* If second arg is constant true, result is true, but we must
10416 evaluate first arg. */
10419 /* Likewise for first arg, but note this only occurs here for
10420 TRUTH_OR_EXPR. */
10424 /* !X || X is always true. */
10428 /* X || !X is always true. */
10433 /* (X && !Y) || (!X && Y) is X ^ Y */
10436 {
10453 }
10462 /* If the second arg is constant zero, drop it. */
10465 /* If the second arg is constant true, this is a logical inversion. */
10467 {
10470 }
10471 /* Identical arguments cancel to zero. */
10475 /* !X ^ X is always true. */
10480 /* X ^ !X is always true. */
10496 /* bool_var != 1 becomes !bool_var. */
10503 /* bool_var == 0 becomes !bool_var. */
10510 /* !exp != 0 becomes !exp */
10515 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10524 {
10530 }
10532 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10541 {
10547 }
10549 /* If this is an EQ or NE comparison with zero and ARG0 is
10550 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10551 two operations, but the latter can be done in one less insn
10552 on machines that have only two-operand insns or on which a
10553 constant cannot be the first operand. */
10556 {
10561 {
10568 arg1);
10569 }
10572 {
10579 arg1);
10580 }
10581 }
10583 /* If this is an NE or EQ comparison of zero against the result of a
10584 signed MOD operation whose second operand is a power of 2, make
10585 the MOD operation unsigned since it is simpler and equivalent. */
10593 {
10603 }
10605 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10606 C1 is a valid shift constant, and C2 is a power of two, i.e.
10607 a single bit. */
10611 == INTEGER_CST
10614 {
10619 /* Check for a valid shift count. */
10621 {
10625 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10626 can be rewritten as (X & (C2 << C1)) != 0. */
10628 {
10633 }
10634 /* Otherwise, for signed (arithmetic) shifts,
10635 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10636 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10640 /* Otherwise, of unsigned (logical) shifts,
10641 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10642 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10643 else
10647 arg000);
10648 }
10649 }
10651 /* If this is a comparison of a field, we may be able to simplify it. */
10654 /* Handle the constant case even without -O
10655 to make sure the warnings are given. */
10657 {
10661 }
10663 /* Optimize comparisons of strlen vs zero to a compare of the
10664 first character of the string vs zero. To wit,
10665 strlen(ptr) == 0 => *ptr == 0
10666 strlen(ptr) != 0 => *ptr != 0
10667 Other cases should reduce to one of these two (or a constant)
10668 due to the return value of strlen being unsigned. */
10671 {
10679 {
10684 }
10685 }
10687 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10688 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10692 {
10697 {
10699 {
10702 }
10705 }
10706 }
10708 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10709 (X & C) == 0 when C is a single bit. */
10714 {
10721 arg1));
10722 }
10724 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10725 constant C is a power of two, i.e. a single bit. */
10732 {
10736 }
10738 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10739 when is C is a power of two, i.e. a single bit. */
10746 {
10752 }
10756 {
10759 }
10761 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10764 {
10772 {
10778 }
10780 {
10786 }
10788 {
10794 }
10796 {
10802 }
10803 }
10807 {
10814 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10815 operand_equal_p guarantees no side-effects so we don't need
10816 to use omit_one_operand on Z. */
10820 arg10));
10824 arg11));
10828 arg10));
10832 arg11));
10834 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10837 {
10843 }
10844 }
10846 /* Attempt to simplify equality/inequality comparisons of complex
10847 values. Only lower the comparison if the result is known or
10848 can be simplified to a single scalar comparison. */
10853 {
10858 {
10861 }
10862 else
10863 {
10866 }
10869 {
10872 }
10873 else
10874 {
10877 }
10881 {
10883 {
10888 }
10889 else
10890 {
10895 }
10896 }
10900 {
10902 {
10907 }
10908 else
10909 {
10914 }
10915 }
10916 }
10928 /* Transform comparisons of the form X +- C CMP X. */
10935 {
10942 else
10945 /* (X - c) > X becomes false. */
10949 {
10953 "occur when assuming that (X - c) > X "
10955 WARN_STRICT_OVERFLOW_ALL);
10957 }
10959 /* Likewise (X + c) < X becomes false. */
10963 {
10967 "occur when assuming that "
10969 WARN_STRICT_OVERFLOW_ALL);
10971 }
10973 /* Convert (X - c) <= X to true. */
10978 {
10982 "occur when assuming that "
10984 WARN_STRICT_OVERFLOW_ALL);
10986 }
10988 /* Convert (X + c) >= X to true. */
10993 {
10997 "occur when assuming that "
10999 WARN_STRICT_OVERFLOW_ALL);
11001 }
11004 {
11005 /* Convert X + c > X and X - c < X to true for integers. */
11009 {
11012 "not occur when assuming that "
11014 WARN_STRICT_OVERFLOW_ALL);
11016 }
11021 {
11024 "not occur when assuming that "
11026 WARN_STRICT_OVERFLOW_ALL);
11028 }
11030 /* Convert X + c <= X and X - c >= X to false for integers. */
11034 {
11037 "not occur when assuming that "
11039 WARN_STRICT_OVERFLOW_ALL);
11041 }
11046 {
11049 "not occur when assuming that "
11051 WARN_STRICT_OVERFLOW_ALL);
11053 }
11054 }
11055 }
11057 /* If we are comparing an ABS_EXPR with a constant, we can
11058 convert all the cases into explicit comparisons, but they may
11059 well not be faster than doing the ABS and one comparison.
11060 But ABS (X) <= C is a range comparison, which becomes a subtraction
11061 and a comparison, and is probably faster. */
11075 /* Convert ABS_EXPR<x> >= 0 to true. */
11082 {
11085 "when simplifying comparison of "
11087 WARN_STRICT_OVERFLOW_CONDITIONAL);
11090 arg0);
11091 }
11093 /* Convert ABS_EXPR<x> < 0 to false. */
11098 {
11101 "when simplifying comparison of "
11103 WARN_STRICT_OVERFLOW_CONDITIONAL);
11106 arg0);
11107 }
11109 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11110 and similarly for >= into !=. */
11120 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11121 otherwise Y might be >= # of bits in X's type and thus e.g.
11122 (unsigned char) (1 << Y) for Y 15 might be 0.
11123 If the cast is widening, then 1 << Y should have unsigned type,
11124 otherwise if Y is number of bits in the signed shift type minus 1,
11125 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11126 31 might be 0xffffffff80000000. */
11137 {
11143 }
11155 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11156 {
11168 }
11173 /* When pedantic, a compound expression can be neither an lvalue
11174 nor an integer constant expression. */
11177 /* Don't let (0, 0) be null pointer constant. */
11183 /* An ASSERT_EXPR should never be passed to fold_binary. */
11189 }
11191 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11192 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11193 of GOTO_EXPR. */
11195 static tree
11197 {
11199 {
11206 /* fall through */
11210 }
11211 }
11213 /* Return whether the sub-tree ST contains a label which is accessible from
11214 outside the sub-tree. */
11216 static bool
11218 {
11219 return
11221 }
11223 /* Fold a ternary expression of code CODE and type TYPE with operands
11224 OP0, OP1, and OP2. Return the folded expression if folding is
11225 successful. Otherwise, return NULL_TREE. */
11227 tree
11230 {
11231 tree tem;
11238 /* If this is a commutative operation, and OP0 is a constant, move it
11239 to OP1 to reduce the number of tests below. */
11248 /* Strip any conversions that don't change the mode. This is safe
11249 for every expression, except for a comparison expression because
11250 its signedness is derived from its operands. So, in the latter
11251 case, only strip conversions that don't change the signedness.
11253 Note that this is done as an internal manipulation within the
11254 constant folder, in order to find the simplest representation of
11255 the arguments so that their form can be studied. In any cases,
11256 the appropriate type conversions should be put back in the tree
11257 that will get out of the constant folder. */
11259 {
11262 }
11265 {
11268 }
11271 {
11274 }
11277 {
11281 {
11287 }
11292 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11293 so all simple results must be passed through pedantic_non_lvalue. */
11295 {
11298 /* Only optimize constant conditions when the selected branch
11299 has the same type as the COND_EXPR. This avoids optimizing
11300 away "c ? x : throw", where the throw has a void type.
11301 Avoid throwing away that operand which contains label. */
11308 }
11310 {
11315 {
11320 {
11328 }
11332 }
11333 }
11335 /* If we have A op B ? A : C, we may be able to convert this to a
11336 simpler expression, depending on the operation and the values
11337 of B and C. Signed zeros prevent all of these transformations,
11338 for reasons given above each one.
11340 Also try swapping the arguments and inverting the conditional. */
11344 {
11348 }
11353 {
11357 {
11361 }
11362 }
11364 /* If the second operand is simpler than the third, swap them
11365 since that produces better jump optimization results. */
11368 {
11370 /* See if this can be inverted. If it can't, possibly because
11371 it was a floating-point inequality comparison, don't do
11372 anything. */
11376 }
11378 /* Convert A ? 1 : 0 to simply A. */
11383 /* If we try to convert OP0 to our type, the
11384 call to fold will try to move the conversion inside
11385 a COND, which will recurse. In that case, the COND_EXPR
11386 is probably the best choice, so leave it alone. */
11390 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11391 over COND_EXPR in cases such as floating point comparisons. */
11400 arg0)));
11402 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11407 {
11408 /* sign_bit_p looks through both zero and sign extensions,
11409 but for this optimization only sign extensions are
11410 usable. */
11413 {
11416 {
11419 }
11421 }
11422 /* sign_bit_p only checks ARG1 bits within A's precision.
11423 If <sign bit of A> has wider type than A, bits outside
11424 of A's precision in <sign bit of A> need to be checked.
11425 If they are all 0, this optimization needs to be done
11426 in unsigned A's type, if they are all 1 in signed A's type,
11427 otherwise this can't be done. */
11433 {
11435 tree tem_type;
11448 {
11451 }
11453 {
11456 }
11457 else
11459 }
11462 return
11468 arg1)));
11469 }
11471 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11472 already handled above. */
11477 {
11487 op1);
11488 }
11490 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11491 is probably obsolete because the first operand should be a
11492 truth value (that's why we have the two cases above), but let's
11493 leave it in until we can confirm this for all front-ends. */
11505 /* Disable the transformations below for vectors, since
11506 fold_binary_op_with_conditional_arg may undo them immediately,
11507 yielding an infinite loop. */
11511 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11520 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11525 {
11527 /* Only perform transformation if ARG0 is easily inverted. */
11531 ? BIT_IOR_EXPR
11534 op1);
11535 }
11537 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11542 {
11544 /* Only perform transformation if ARG0 is easily inverted. */
11550 op2);
11551 }
11553 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11565 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11566 of fold_ternary on them. */
11574 {
11584 {
11589 {
11597 }
11598 }
11599 }
11601 /* On constants we can use native encode/interpret to constant
11602 fold (nearly) all BIT_FIELD_REFs. */
11606 {
11609 /* Limit us to a reasonable amount of work. To relax the
11610 other limitations we need bit-shifting of the buffer
11611 and rounding up the size. */
11615 {
11617 unsigned HOST_WIDE_INT len
11622 {
11627 }
11628 }
11629 }
11634 /* For integers we can decompose the FMA if possible. */
11646 {
11662 {
11667 /* Make sure that the perm value is in an acceptable
11668 range. */
11677 else
11685 }
11688 {
11693 }
11698 {
11703 }
11709 {
11713 }
11718 /* Some targets are deficient and fail to expand a single
11719 argument permutation while still allowing an equivalent
11720 2-argument version. */
11724 {
11727 }
11730 {
11737 }
11741 }
11745 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11748 {
11754 wide_int tem2
11758 }
11763 {
11765 unsigned HOST_WIDE_INT elsize
11768 {
11772 else
11773 {
11781 }
11782 }
11783 }
11789 }
11791 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11792 of an array (or vector). */
11794 tree
11796 {
11801 {
11804 {
11805 /* Static constructors for variably sized objects makes no sense. */
11809 }
11810 }
11821 offset_int max_index;
11826 {
11827 /* Array constructor might explicitly set index, or specify a range,
11828 or leave index NULL meaning that it is next index after previous
11829 one. */
11831 {
11834 else
11835 {
11839 }
11840 }
11841 else
11842 {
11848 }
11850 /* Do we have match? */
11854 }
11856 }
11858 /* Perform constant folding and related simplification of EXPR.
11859 The related simplifications include x*1 => x, x*0 => 0, etc.,
11860 and application of the associative law.
11861 NOP_EXPR conversions may be removed freely (as long as we
11862 are careful not to change the type of the overall expression).
11863 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11864 but we can constant-fold them if they have constant operands. */
11866 #ifdef ENABLE_FOLD_CHECKING
11867 # define fold(x) fold_1 (x)
11869 static
11870 #endif
11871 tree
11873 {
11877 tree tem;
11880 /* Return right away if a constant. */
11884 /* CALL_EXPR-like objects with variable numbers of operands are
11885 treated specially. */
11887 {
11889 {
11892 }
11894 }
11897 {
11902 {
11920 }
11921 }
11924 {
11926 {
11933 {
11938 }
11941 }
11943 /* Return a VECTOR_CST if possible. */
11945 {
11951 tree val;
11957 }
11965 }
11967 #ifdef ENABLE_FOLD_CHECKING
11968 #undef fold
11975 /* When --enable-checking=fold, compute a digest of expr before
11976 and after actual fold call to see if fold did not accidentally
11977 change original expr. */
11979 tree
11981 {
11982 tree ret;
12002 }
12004 void
12006 {
12017 }
12019 static void
12021 {
12023 }
12025 static void
12028 {
12034 recursive_label:
12044 {
12045 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12050 }
12058 {
12059 /* Allow these fields to be modified. */
12060 tree tmp;
12069 {
12072 }
12073 }
12084 {
12087 {
12102 }
12106 {
12119 }
12136 {
12142 }
12145 {
12147 {
12150 }
12152 }
12163 {
12166 }
12176 }
12177 }
12179 /* Helper function for outputting the checksum of a tree T. When
12180 debugging with gdb, you can "define mynext" to be "next" followed
12181 by "call debug_fold_checksum (op0)", then just trace down till the
12182 outputs differ. */
12184 DEBUG_FUNCTION void
12186 {
12201 }
12203 #endif
12205 /* Fold a unary tree expression with code CODE of type TYPE with an
12206 operand OP0. LOC is the location of the resulting expression.
12207 Return a folded expression if successful. Otherwise, return a tree
12208 expression with code CODE of type TYPE with an operand OP0. */
12210 tree
12213 {
12214 tree tem;
12215 #ifdef ENABLE_FOLD_CHECKING
12224 #endif
12230 #ifdef ENABLE_FOLD_CHECKING
12237 #endif
12239 }
12241 /* Fold a binary tree expression with code CODE of type TYPE with
12242 operands OP0 and OP1. LOC is the location of the resulting
12243 expression. Return a folded expression if successful. Otherwise,
12244 return a tree expression with code CODE of type TYPE with operands
12245 OP0 and OP1. */
12247 tree
12250 MEM_STAT_DECL)
12251 {
12252 tree tem;
12253 #ifdef ENABLE_FOLD_CHECKING
12270 #endif
12276 #ifdef ENABLE_FOLD_CHECKING
12291 #endif
12293 }
12295 /* Fold a ternary tree expression with code CODE of type TYPE with
12296 operands OP0, OP1, and OP2. Return a folded expression if
12297 successful. Otherwise, return a tree expression with code CODE of
12298 type TYPE with operands OP0, OP1, and OP2. */
12300 tree
12303 {
12304 tree tem;
12305 #ifdef ENABLE_FOLD_CHECKING
12329 #endif
12336 #ifdef ENABLE_FOLD_CHECKING
12359 #endif
12361 }
12363 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12364 arguments in ARGARRAY, and a null static chain.
12365 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12366 of type TYPE from the given operands as constructed by build_call_array. */
12368 tree
12371 {
12372 tree tem;
12373 #ifdef ENABLE_FOLD_CHECKING
12392 #endif
12398 #ifdef ENABLE_FOLD_CHECKING
12414 #endif
12416 }
12418 /* Perform constant folding and related simplification of initializer
12419 expression EXPR. These behave identically to "fold_buildN" but ignore
12420 potential run-time traps and exceptions that fold must preserve. */
12422 #define START_FOLD_INIT \
12423 int saved_signaling_nans = flag_signaling_nans;\
12424 int saved_trapping_math = flag_trapping_math;\
12425 int saved_rounding_math = flag_rounding_math;\
12426 int saved_trapv = flag_trapv;\
12427 int saved_folding_initializer = folding_initializer;\
12428 flag_signaling_nans = 0;\
12429 flag_trapping_math = 0;\
12430 flag_rounding_math = 0;\
12431 flag_trapv = 0;\
12432 folding_initializer = 1;
12434 #define END_FOLD_INIT \
12435 flag_signaling_nans = saved_signaling_nans;\
12436 flag_trapping_math = saved_trapping_math;\
12437 flag_rounding_math = saved_rounding_math;\
12438 flag_trapv = saved_trapv;\
12439 folding_initializer = saved_folding_initializer;
12441 tree
12444 {
12445 tree result;
12446 START_FOLD_INIT;
12450 END_FOLD_INIT;
12452 }
12454 tree
12457 {
12458 tree result;
12459 START_FOLD_INIT;
12463 END_FOLD_INIT;
12465 }
12467 tree
12470 {
12471 tree result;
12472 START_FOLD_INIT;
12476 END_FOLD_INIT;
12478 }
12480 #undef START_FOLD_INIT
12481 #undef END_FOLD_INIT
12483 /* Determine if first argument is a multiple of second argument. Return 0 if
12484 it is not, or we cannot easily determined it to be.
12486 An example of the sort of thing we care about (at this point; this routine
12487 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12488 fold cases do now) is discovering that
12490 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12492 is a multiple of
12494 SAVE_EXPR (J * 8)
12496 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12498 This code also handles discovering that
12500 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12502 is a multiple of 8 so we don't have to worry about dealing with a
12503 possible remainder.
12505 Note that we *look* inside a SAVE_EXPR only to determine how it was
12506 calculated; it is not safe for fold to do much of anything else with the
12507 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12508 at run time. For example, the latter example above *cannot* be implemented
12509 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12510 evaluation time of the original SAVE_EXPR is not necessarily the same at
12511 the time the new expression is evaluated. The only optimization of this
12512 sort that would be valid is changing
12514 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12516 divided by 8 to
12518 SAVE_EXPR (I) * SAVE_EXPR (J)
12520 (where the same SAVE_EXPR (J) is used in the original and the
12521 transformed version). */
12523 int
12525 {
12536 {
12538 /* Bitwise and provides a power of two multiple. If the mask is
12539 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12542 /* FALLTHRU */
12549 /* It is impossible to prove if op0 - op1 is multiple of bottom
12550 precisely, so be conservative here checking if both op0 and op1
12551 are multiple of bottom. Note we check the second operand first
12552 since it's usually simpler. */
12557 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12558 as op0 - 3 if the expression has unsigned type. For example,
12559 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12569 {
12571 /* const_binop may not detect overflow correctly,
12572 so check for it explicitly here. */
12576 size_one_node,
12577 op1)))
12580 }
12584 /* Can't handle conversions from non-integral or wider integral type. */
12590 /* fall through */
12607 SIGNED);
12613 {
12616 /* Check for special cases to see if top is defined as multiple
12617 of bottom:
12619 top = (X & ~(bottom - 1) ; bottom is power of 2
12621 or
12623 Y = X % bottom
12624 top = X - Y. */
12643 }
12645 /* fall through */
12649 }
12650 }
12652 #define tree_expr_nonnegative_warnv_p(X, Y) \
12655 #define RECURSE(X) \
12656 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12658 /* Return true if CODE or TYPE is known to be non-negative. */
12660 static bool
12662 {
12665 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12666 have a signed:1 type (where the value is -1 and 0). */
12669 }
12671 /* Return true if (CODE OP0) is known to be non-negative. If the return
12672 value is based on the assumption that signed overflow is undefined,
12673 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12674 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12676 bool
12679 {
12684 {
12686 /* We can't return 1 if flag_wrapv is set because
12687 ABS_EXPR<INT_MIN> = INT_MIN. */
12691 {
12694 }
12702 CASE_CONVERT:
12703 {
12708 {
12712 {
12716 }
12717 }
12719 {
12725 }
12726 }
12731 }
12733 /* We don't know sign of `t', so be conservative and return false. */
12735 }
12737 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12738 value is based on the assumption that signed overflow is undefined,
12739 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12740 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12742 bool
12746 {
12751 {
12757 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12758 both unsigned and at least 2 bits shorter than the result. */
12762 {
12767 {
12771 }
12772 }
12777 {
12778 /* x * x is always non-negative for floating point x
12779 or without overflow. */
12782 {
12787 }
12788 }
12790 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12791 both unsigned and their total bits is shorter than the result. */
12795 {
12814 {
12824 }
12825 }
12852 }
12854 /* We don't know sign of `t', so be conservative and return false. */
12856 }
12858 /* Return true if T 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
12865 {
12870 {
12884 /* Limit the depth of recursion to avoid quadratic behavior.
12885 This is expected to catch almost all occurrences in practice.
12886 If this code misses important cases that unbounded recursion
12887 would not, passes that need this information could be revised
12888 to provide it through dataflow propagation. */
12896 }
12897 }
12899 /* Return true if T is known to be non-negative. If the return
12900 value is based on the assumption that signed overflow is undefined,
12901 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12902 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12904 bool
12907 {
12909 {
12910 CASE_CFN_ACOS:
12911 CASE_CFN_ACOSH:
12912 CASE_CFN_CABS:
12913 CASE_CFN_COSH:
12914 CASE_CFN_ERFC:
12915 CASE_CFN_EXP:
12916 CASE_CFN_EXP10:
12917 CASE_CFN_EXP2:
12918 CASE_CFN_FABS:
12919 CASE_CFN_FDIM:
12920 CASE_CFN_HYPOT:
12921 CASE_CFN_POW10:
12922 CASE_CFN_FFS:
12923 CASE_CFN_PARITY:
12924 CASE_CFN_POPCOUNT:
12925 CASE_CFN_CLZ:
12926 CASE_CFN_CLRSB:
12929 /* Always true. */
12932 CASE_CFN_SQRT:
12933 /* sqrt(-0.0) is -0.0. */
12938 CASE_CFN_ASINH:
12939 CASE_CFN_ATAN:
12940 CASE_CFN_ATANH:
12941 CASE_CFN_CBRT:
12942 CASE_CFN_CEIL:
12943 CASE_CFN_ERF:
12944 CASE_CFN_EXPM1:
12945 CASE_CFN_FLOOR:
12946 CASE_CFN_FMOD:
12947 CASE_CFN_FREXP:
12948 CASE_CFN_ICEIL:
12949 CASE_CFN_IFLOOR:
12950 CASE_CFN_IRINT:
12951 CASE_CFN_IROUND:
12952 CASE_CFN_LCEIL:
12953 CASE_CFN_LDEXP:
12954 CASE_CFN_LFLOOR:
12955 CASE_CFN_LLCEIL:
12956 CASE_CFN_LLFLOOR:
12957 CASE_CFN_LLRINT:
12958 CASE_CFN_LLROUND:
12959 CASE_CFN_LRINT:
12960 CASE_CFN_LROUND:
12961 CASE_CFN_MODF:
12962 CASE_CFN_NEARBYINT:
12963 CASE_CFN_RINT:
12964 CASE_CFN_ROUND:
12965 CASE_CFN_SCALB:
12966 CASE_CFN_SCALBLN:
12967 CASE_CFN_SCALBN:
12968 CASE_CFN_SIGNBIT:
12969 CASE_CFN_SIGNIFICAND:
12970 CASE_CFN_SINH:
12971 CASE_CFN_TANH:
12972 CASE_CFN_TRUNC:
12973 /* True if the 1st argument is nonnegative. */
12976 CASE_CFN_FMAX:
12977 /* True if the 1st OR 2nd arguments are nonnegative. */
12980 CASE_CFN_FMIN:
12981 /* True if the 1st AND 2nd arguments are nonnegative. */
12984 CASE_CFN_COPYSIGN:
12985 /* True if the 2nd argument is nonnegative. */
12988 CASE_CFN_POWI:
12989 /* True if the 1st argument is nonnegative or the second
12990 argument is an even integer. */
12996 CASE_CFN_POW:
12997 /* True if the 1st argument is nonnegative or the second
12998 argument is an even integer valued real. */
13000 {
13001 REAL_VALUE_TYPE c;
13002 HOST_WIDE_INT n;
13007 {
13008 REAL_VALUE_TYPE cint;
13012 }
13013 }
13018 }
13020 }
13022 /* Return true if T is known to be non-negative. If the return
13023 value is based on the assumption that signed overflow is undefined,
13024 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13025 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13027 static bool
13029 {
13035 {
13037 {
13041 /* If the initializer is non-void, then it's a normal expression
13042 that will be assigned to the slot. */
13046 /* Otherwise, the initializer sets the slot in some way. One common
13047 way is an assignment statement at the end of the initializer. */
13049 {
13057 else
13059 }
13065 }
13068 {
13074 arg0,
13075 arg1,
13077 }
13090 }
13091 }
13093 #undef RECURSE
13094 #undef tree_expr_nonnegative_warnv_p
13096 /* Return true if T is known to be non-negative. If the return
13097 value is based on the assumption that signed overflow is undefined,
13098 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13099 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13101 bool
13103 {
13110 {
13132 }
13135 {
13161 }
13162 }
13164 /* Return true if `t' is known to be non-negative. Handle warnings
13165 about undefined signed overflow. */
13167 bool
13169 {
13176 "determining that expression is always "
13178 WARN_STRICT_OVERFLOW_MISC);
13180 }
13183 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13184 For floating point we further ensure that T is not denormal.
13185 Similar logic is present in nonzero_address in rtlanal.h.
13187 If the return value is based on the assumption that signed overflow
13188 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13189 change *STRICT_OVERFLOW_P. */
13191 bool
13194 {
13196 {
13199 strict_overflow_p);
13202 {
13208 strict_overflow_p));
13209 }
13214 strict_overflow_p);
13218 }
13221 }
13223 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13224 For floating point we further ensure that T is not denormal.
13225 Similar logic is present in nonzero_address in rtlanal.h.
13227 If the return value is based on the assumption that signed overflow
13228 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13229 change *STRICT_OVERFLOW_P. */
13231 bool
13233 tree type,
13234 tree op0,
13236 {
13239 {
13243 {
13244 /* With the presence of negative values it is hard
13245 to say something. */
13252 /* One of operands must be positive and the other non-negative. */
13253 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13254 overflows, on a twos-complement machine the sum of two
13255 nonnegative numbers can never be zero. */
13257 strict_overflow_p)
13259 strict_overflow_p));
13260 }
13265 {
13267 strict_overflow_p)
13269 strict_overflow_p))
13270 {
13273 }
13274 }
13283 {
13286 }
13293 {
13297 /* When both operands are nonzero, then MAX must be too. */
13299 strict_overflow_p))
13302 /* MAX where operand 0 is positive is positive. */
13304 strict_overflow_p);
13305 }
13306 /* MAX where operand 1 is positive is positive. */
13311 {
13315 }
13320 strict_overflow_p)
13322 strict_overflow_p));
13326 }
13329 }
13331 /* Return true when T is an address and is known to be nonzero.
13332 For floating point we further ensure that T is not denormal.
13333 Similar logic is present in nonzero_address in rtlanal.h.
13335 If the return value is based on the assumption that signed overflow
13336 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13337 change *STRICT_OVERFLOW_P. */
13339 bool
13341 {
13344 {
13349 {
13361 /* For objects in symbol table check if we know they are non-zero.
13362 Don't do anything for variables and functions before symtab is built;
13363 it is quite possible that they will be declared weak later. */
13368 /* Constants are never weak. */
13373 }
13381 {
13385 }
13395 }
13397 }
13399 #define integer_valued_real_p(X) \
13402 #define RECURSE(X) \
13403 ((integer_valued_real_p) (X, depth + 1))
13405 /* Return true if the floating point result of (CODE OP0) has an
13406 integer value. We also allow +Inf, -Inf and NaN to be considered
13407 integer values. Return false for signaling NaN.
13409 DEPTH is the current nesting depth of the query. */
13411 bool
13413 {
13415 {
13422 CASE_CONVERT:
13423 {
13430 }
13434 }
13436 }
13438 /* Return true if the floating point result of (CODE OP0 OP1) has an
13439 integer value. We also allow +Inf, -Inf and NaN to be considered
13440 integer values. Return false for signaling NaN.
13442 DEPTH is the current nesting depth of the query. */
13444 bool
13446 {
13448 {
13458 }
13460 }
13462 /* Return true if the floating point result of calling FNDECL with arguments
13463 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13464 considered integer values. Return false for signaling NaN. If FNDECL
13465 takes fewer than 2 arguments, the remaining ARGn are null.
13467 DEPTH is the current nesting depth of the query. */
13469 bool
13471 {
13473 {
13474 CASE_CFN_CEIL:
13475 CASE_CFN_FLOOR:
13476 CASE_CFN_NEARBYINT:
13477 CASE_CFN_RINT:
13478 CASE_CFN_ROUND:
13479 CASE_CFN_TRUNC:
13482 CASE_CFN_FMIN:
13483 CASE_CFN_FMAX:
13488 }
13490 }
13492 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13493 has an integer value. We also allow +Inf, -Inf and NaN to be
13494 considered integer values. Return false for signaling NaN.
13496 DEPTH is the current nesting depth of the query. */
13498 bool
13500 {
13502 {
13510 /* Limit the depth of recursion to avoid quadratic behavior.
13511 This is expected to catch almost all occurrences in practice.
13512 If this code misses important cases that unbounded recursion
13513 would not, passes that need this information could be revised
13514 to provide it through dataflow propagation. */
13518 depth));
13522 }
13524 }
13526 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13527 has an integer value. We also allow +Inf, -Inf and NaN to be
13528 considered integer values. Return false for signaling NaN.
13530 DEPTH is the current nesting depth of the query. */
13532 static bool
13534 {
13536 {
13547 }
13549 }
13551 #undef RECURSE
13552 #undef integer_valued_real_p
13554 /* Return true if the floating point expression T has an integer value.
13555 We also allow +Inf, -Inf and NaN to be considered integer values.
13556 Return false for signaling NaN.
13558 DEPTH is the current nesting depth of the query. */
13560 bool
13562 {
13568 {
13584 }
13587 {
13593 {
13602 }
13606 }
13607 }
13609 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13610 attempt to fold the expression to a constant without modifying TYPE,
13611 OP0 or OP1.
13613 If the expression could be simplified to a constant, then return
13614 the constant. If the expression would not be simplified to a
13615 constant, then return NULL_TREE. */
13617 tree
13619 {
13622 }
13624 /* Given the components of a unary expression CODE, TYPE and OP0,
13625 attempt to fold the expression to a constant without modifying
13626 TYPE or OP0.
13628 If the expression could be simplified to a constant, then return
13629 the constant. If the expression would not be simplified to a
13630 constant, then return NULL_TREE. */
13632 tree
13634 {
13637 }
13639 /* If EXP represents referencing an element in a constant string
13640 (either via pointer arithmetic or array indexing), return the
13641 tree representing the value accessed, otherwise return NULL. */
13643 tree
13645 {
13649 {
13651 tree index;
13652 tree string;
13657 else
13658 {
13662 /* Optimize the special-case of a zero lower bound.
13664 We convert the low_bound to sizetype to avoid some problems
13665 with constant folding. (E.g. suppose the lower bound is 1,
13666 and its mode is QI. Without the conversion,l (ARRAY
13667 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13668 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13674 }
13676 scalar_int_mode char_mode;
13688 }
13690 }
13692 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13693 an integer constant, real, or fixed-point constant.
13695 TYPE is the type of the result. */
13697 static tree
13699 {
13703 {
13705 {
13712 }
13719 {
13720 FIXED_VALUE_TYPE f;
13725 /* Propagate overflow flags. */
13729 }
13733 }
13736 }
13738 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13739 an integer constant or real constant.
13741 TYPE is the type of the result. */
13743 tree
13745 {
13749 {
13751 {
13752 /* If the value is unsigned or non-negative, then the absolute value
13753 is the same as the ordinary value. */
13757 /* If the value is negative, then the absolute value is
13758 its negation. */
13759 else
13760 {
13765 }
13766 }
13772 else
13778 }
13781 }
13783 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13784 constant. TYPE is the type of the result. */
13786 static tree
13788 {
13792 }
13794 /* Given CODE, a relational operator, the target type, TYPE and two
13795 constant operands OP0 and OP1, return the result of the
13796 relational operation. If the result is not a compile time
13797 constant, then return NULL_TREE. */
13799 static tree
13801 {
13804 /* From here on, the only cases we handle are when the result is
13805 known to be a constant. */
13808 {
13812 /* Handle the cases where either operand is a NaN. */
13814 {
13816 {
13844 }
13847 }
13850 }
13853 {
13857 }
13859 /* Handle equality/inequality of complex constants. */
13861 {
13872 else
13874 }
13877 {
13879 {
13880 /* Have vector comparison with scalar boolean result. */
13884 {
13892 }
13894 }
13901 {
13914 }
13917 }
13919 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13921 To compute GT, swap the arguments and do LT.
13922 To compute GE, do LT and invert the result.
13923 To compute LE, swap the arguments, do LT and invert the result.
13924 To compute NE, do EQ and invert the result.
13926 Therefore, the code below must handle only EQ and LT. */
13929 {
13932 }
13934 /* Note that it is safe to invert for real values here because we
13935 have already handled the one case that it matters. */
13939 {
13942 }
13944 /* Compute a result for LT or EQ if args permit;
13945 Otherwise return T. */
13947 {
13950 else
13952 }
13953 else
13959 }
13961 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13962 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13963 itself. */
13965 tree
13967 {
13968 /* If the expression does not have side effects then we don't have to wrap
13969 it with a cleanup point expression. */
13973 /* If the expression is a return, check to see if the expression inside the
13974 return has no side effects or the right hand side of the modify expression
13975 inside the return. If either don't have side effects set we don't need to
13976 wrap the expression in a cleanup point expression. Note we don't check the
13977 left hand side of the modify because it should always be a return decl. */
13979 {
13986 }
13989 }
13991 /* Given a pointer value OP0 and a type TYPE, return a simplified version
13992 of an indirection through OP0, or NULL_TREE if no simplification is
13993 possible. */
13995 tree
13997 {
13999 tree subtype;
14008 {
14011 /* *&CONST_DECL -> to the value of the const decl. */
14014 /* *&p => p; make sure to handle *&"str"[cst] here. */
14016 {
14020 else
14022 }
14023 /* *(foo *)&fooarray => fooarray[0] */
14026 && (!in_gimple_form
14028 {
14038 }
14039 /* *(foo *)&complexfoo => __real__ complexfoo */
14043 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14046 {
14050 }
14051 }
14055 {
14061 {
14062 tree op00type;
14066 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14069 {
14071 unsigned HOST_WIDE_INT max_offset
14076 {
14083 }
14084 }
14085 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14088 {
14092 }
14093 /* ((foo *)&fooarray)[1] => fooarray[1] */
14096 {
14103 offset_int remainder;
14106 {
14111 }
14112 }
14113 }
14114 }
14116 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14119 && (!in_gimple_form
14121 {
14122 tree type_domain;
14132 NULL_TREE);
14133 }
14136 }
14138 /* Builds an expression for an indirection through T, simplifying some
14139 cases. */
14141 tree
14143 {
14151 }
14153 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14155 tree
14157 {
14162 else
14164 }
14166 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14167 whose result is ignored. The type of the returned tree need not be
14168 the same as the original expression. */
14170 tree
14172 {
14178 {
14189 else
14195 {
14211 }
14216 }
14217 }
14219 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14221 tree
14223 {
14229 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14230 have to do anything. Only do this when we are not given a const,
14231 because in that case, this check is more expensive than just
14232 doing it. */
14234 {
14239 }
14241 /* If divisor is a power of two, simplify this to bit manipulation. */
14243 {
14245 {
14259 }
14260 else
14261 {
14262 tree t;
14268 }
14269 }
14270 else
14271 {
14276 }
14279 }
14281 /* Likewise, but round down. */
14283 tree
14285 {
14292 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14293 have to do anything. Only do this when we are not given a const,
14294 because in that case, this check is more expensive than just
14295 doing it. */
14297 {
14302 }
14304 /* If divisor is a power of two, simplify this to bit manipulation. */
14306 {
14307 tree t;
14311 }
14312 else
14313 {
14318 }
14321 }
14323 /* Returns the pointer to the base of the object addressed by EXP and
14324 extracts the information about the offset of the access, storing it
14325 to PBITPOS and POFFSET. */
14327 static tree
14330 {
14331 tree core;
14332 machine_mode mode;
14334 HOST_WIDE_INT bitsize;
14338 {
14343 }
14345 {
14351 {
14356 {
14359 }
14360 }
14361 }
14362 else
14363 {
14367 }
14370 }
14372 /* Returns true if addresses of E1 and E2 differ by a constant, false
14373 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14375 bool
14377 {
14391 {
14401 }
14403 {
14404 /* If only one of the offsets is non-constant, the difference cannot
14405 be a constant. */
14407 }
14408 else
14413 }
14415 /* Return OFF converted to a pointer offset type suitable as offset for
14416 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14417 tree
14419 {
14421 }
14423 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14424 tree
14426 {
14429 }
14431 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14432 tree
14434 {
14437 }
14439 /* Return a char pointer for a C string if it is a string constant
14440 or sum of string constant and integer constant. We only support
14441 string constants properly terminated with '\0' character.
14442 If STRLEN is a valid pointer, length (including terminating character)
14443 of returned string is stored to the argument. */
14447 {
14448 tree offset_node;
14459 {
14462 else
14464 }
14469 /* Support only properly null-terminated strings. */
14478 }
14480 #if CHECKING_P
14484 /* Helper functions for writing tests of folding trees. */
14486 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14488 static void
14490 tree constant)
14491 {
14493 }
14495 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14496 wrapping WRAPPED_EXPR. */
14498 static void
14500 tree wrapped_expr)
14501 {
14506 }
14508 /* Verify that various arithmetic binary operations are folded
14509 correctly. */
14511 static void
14513 {
14519 /* Addition. */
14520 /* 1 <-- (0 + 1) */
14522 one);
14524 one);
14526 /* (nonlvalue)x <-- (x + 0) */
14528 x);
14530 /* Subtraction. */
14531 /* 0 <-- (x - x) */
14533 zero);
14535 x);
14537 /* Multiplication. */
14538 /* 0 <-- (x * 0) */
14540 zero);
14542 /* (nonlvalue)x <-- (x * 1) */
14544 x);
14545 }
14547 /* Verify that various binary operations on vectors are folded
14548 correctly. */
14550 static void
14552 {
14558 /* Verify equality tests that return a scalar boolean result. */
14564 }
14566 /* Run all of the selftests within this file. */
14568 void
14570 {
14573 }