| blob | b48296ca1118041ed2606d14bad0ad10161391f0 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2019 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. */
86 /* Nonzero if we are folding constants inside an initializer; zero
87 otherwise. */
90 /* The following constants represent a bit based encoding of GCC's
91 comparison operators. This encoding simplifies transformations
92 on relational comparison operators, such as AND and OR. */
110 };
143 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
144 Otherwise, return LOC. */
146 static location_t
148 {
151 }
153 /* Similar to protected_set_expr_location, but never modify x in place,
154 if location can and needs to be set, unshare it. */
158 {
164 {
167 }
169 }
170 \f
171 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
172 division and returns the quotient. Otherwise returns
173 NULL_TREE. */
175 tree
177 {
178 widest_int quo;
185 }
186 \f
187 /* This is nonzero if we should defer warnings about undefined
188 overflow. This facility exists because these warnings are a
189 special case. The code to estimate loop iterations does not want
190 to issue any warnings, since it works with expressions which do not
191 occur in user code. Various bits of cleanup code call fold(), but
192 only use the result if it has certain characteristics (e.g., is a
193 constant); that code only wants to issue a warning if the result is
194 used. */
198 /* If a warning about undefined overflow is deferred, this is the
199 warning. Note that this may cause us to turn two warnings into
200 one, but that is fine since it is sufficient to only give one
201 warning per expression. */
205 /* If a warning about undefined overflow is deferred, this is the
206 level at which the warning should be emitted. */
210 /* Start deferring overflow warnings. We could use a stack here to
211 permit nested calls, but at present it is not necessary. */
213 void
215 {
217 }
219 /* Stop deferring overflow warnings. If there is a pending warning,
220 and ISSUE is true, then issue the warning if appropriate. STMT is
221 the statement with which the warning should be associated (used for
222 location information); STMT may be NULL. CODE is the level of the
223 warning--a warn_strict_overflow_code value. This function will use
224 the smaller of CODE and the deferred code when deciding whether to
225 issue the warning. CODE may be zero to mean to always use the
226 deferred code. */
228 void
230 {
232 location_t locus;
237 {
243 }
254 /* Use the smallest code level when deciding to issue the
255 warning. */
264 else
267 }
269 /* Stop deferring overflow warnings, ignoring any deferred
270 warnings. */
272 void
274 {
276 }
278 /* Whether we are deferring overflow warnings. */
280 bool
282 {
284 }
286 /* This is called when we fold something based on the fact that signed
287 overflow is undefined. */
289 void
291 {
293 {
296 {
299 }
300 }
303 }
304 \f
305 /* Return true if the built-in mathematical function specified by CODE
306 is odd, i.e. -f(x) == f(-x). */
308 bool
310 {
312 {
313 CASE_CFN_ASIN:
314 CASE_CFN_ASINH:
315 CASE_CFN_ATAN:
316 CASE_CFN_ATANH:
317 CASE_CFN_CASIN:
318 CASE_CFN_CASINH:
319 CASE_CFN_CATAN:
320 CASE_CFN_CATANH:
321 CASE_CFN_CBRT:
322 CASE_CFN_CPROJ:
323 CASE_CFN_CSIN:
324 CASE_CFN_CSINH:
325 CASE_CFN_CTAN:
326 CASE_CFN_CTANH:
327 CASE_CFN_ERF:
328 CASE_CFN_LLROUND:
329 CASE_CFN_LROUND:
330 CASE_CFN_ROUND:
331 CASE_CFN_ROUNDEVEN:
332 CASE_CFN_ROUNDEVEN_FN:
333 CASE_CFN_SIN:
334 CASE_CFN_SINH:
335 CASE_CFN_TAN:
336 CASE_CFN_TANH:
337 CASE_CFN_TRUNC:
340 CASE_CFN_LLRINT:
341 CASE_CFN_LRINT:
342 CASE_CFN_NEARBYINT:
343 CASE_CFN_RINT:
348 }
350 }
352 /* Check whether we may negate an integer constant T without causing
353 overflow. */
355 bool
357 {
358 tree type;
367 }
369 /* Determine whether an expression T can be cheaply negated using
370 the function negate_expr without introducing undefined overflow. */
372 static bool
374 {
375 tree type;
384 {
389 /* Check that -CST will not overflow type. */
402 /* We want to canonicalize to positive real constants. Pretend
403 that only negative ones can be easily negated. */
411 {
415 /* Steps don't prevent negation. */
422 }
437 /* -(A + B) -> (-B) - A. */
440 /* -(A + B) -> (-A) - B. */
444 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
453 /* INT_MIN/n * n doesn't overflow while negating one operand it does
454 if n is a (negative) power of two. */
465 /* Fall through. */
478 /* In general we can't negate A in A / B, because if A is INT_MIN and
479 B is not 1 we change the sign of the result. */
483 /* In general we can't negate B in A / B, because if A is INT_MIN and
484 B is 1, we may turn this into INT_MIN / -1 which is undefined
485 and actually traps on some architectures. */
494 /* Negate -((double)float) as (double)(-float). */
496 {
500 }
504 /* Negate -f(x) as f(-x). */
510 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
512 {
516 }
521 }
523 }
525 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
526 simplification is possible.
527 If negate_expr_p would return true for T, NULL_TREE will never be
528 returned. */
530 static tree
532 {
534 tree tem;
537 {
538 /* Convert - (~A) to A + 1. */
562 {
567 }
571 {
572 tree_vector_builder elts;
576 {
581 }
584 }
607 {
608 /* -(A + B) -> (-B) - A. */
610 {
614 }
616 /* -(A + B) -> (-A) - B. */
618 {
622 }
623 }
627 /* - (A - B) -> B - A */
638 /* Fall through. */
642 {
651 }
659 /* In general we can't negate A in A / B, because if A is INT_MIN and
660 B is not 1 we change the sign of the result. */
666 /* In general we can't negate B in A / B, because if A is INT_MIN and
667 B is 1, we may turn this into INT_MIN / -1 which is undefined
668 and actually traps on some architectures. */
680 /* Convert -((double)float) into (double)(-float). */
682 {
686 }
690 /* Negate -f(x) as f(-x). */
693 {
699 }
703 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
705 {
708 {
715 }
716 }
721 }
724 }
726 /* A wrapper for fold_negate_expr_1. */
728 static tree
730 {
737 }
739 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
740 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
741 return NULL_TREE. */
743 static tree
745 {
747 location_t loc;
760 }
761 \f
762 /* Split a tree IN into a constant, literal and variable parts that could be
763 combined with CODE to make IN. "constant" means an expression with
764 TREE_CONSTANT but that isn't an actual constant. CODE must be a
765 commutative arithmetic operation. Store the constant part into *CONP,
766 the literal in *LITP and return the variable part. If a part isn't
767 present, set it to null. If the tree does not decompose in this way,
768 return the entire tree as the variable part and the other parts as null.
770 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
771 case, we negate an operand that was subtracted. Except if it is a
772 literal for which we use *MINUS_LITP instead.
774 If NEGATE_P is true, we are negating all of IN, again except a literal
775 for which we use *MINUS_LITP instead. If a variable part is of pointer
776 type, it is negated after converting to TYPE. This prevents us from
777 generating illegal MINUS pointer expression. LOC is the location of
778 the converted variable part.
780 If IN is itself a literal or constant, return it as appropriate.
782 Note that we do not guarantee that any of the three values will be the
783 same type as IN, but they will have the same signedness and mode. */
785 static tree
789 {
797 /* Strip any conversions that don't change the machine mode or signedness. */
806 /* We can associate addition and subtraction together (even
807 though the C standard doesn't say so) for integers because
808 the value is not affected. For reals, the value might be
809 affected, so we can't. */
815 {
821 /* First see if either of the operands is a literal, then a constant. */
834 /* If we haven't dealt with either operand, this is not a case we can
835 decompose. Otherwise, VAR is either of the ones remaining, if any. */
840 else
843 /* Now do any needed negations. */
850 }
855 {
856 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
857 when IN is constant. */
860 }
861 else
865 {
878 }
888 }
890 /* Re-associate trees split by the above function. T1 and T2 are
891 either expressions to associate or null. Return the new
892 expression, if any. LOC is the location of the new expression. If
893 we build an operation, do it in TYPE and with CODE. */
895 static tree
897 {
899 {
902 }
906 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
907 try to fold this since we will have infinite recursion. But do
908 deal with any NEGATE_EXPRs. */
912 {
914 {
927 }
929 {
932 }
936 }
940 }
941 \f
942 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
943 for use in int_const_binop, size_binop and size_diffop. */
945 static bool
947 {
954 {
963 }
968 }
970 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
971 a new constant in RES. Return FALSE if we don't know how to
972 evaluate CODE at compile-time. */
974 bool
978 {
979 wide_int tmp;
982 {
998 {
1002 else
1004 }
1005 else
1009 /* It's unclear from the C standard whether shifts can overflow.
1010 The following code ignores overflow; perhaps a C standard
1011 interpretation ruling is needed. */
1013 else
1020 {
1024 else
1026 }
1027 else
1032 else
1111 }
1113 }
1115 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1116 produce a new constant in RES. Return FALSE if we don't know how
1117 to evaluate CODE at compile-time. */
1119 static bool
1123 {
1127 {
1145 else
1152 else
1165 }
1167 }
1169 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1170 produce a new constant. Return NULL_TREE if we don't know how to
1171 evaluate CODE at compile-time. */
1173 tree
1176 {
1177 poly_wide_int poly_res;
1183 {
1189 }
1198 }
1200 /* Return true if binary operation OP distributes over addition in operand
1201 OPNO, with the other operand being held constant. OPNO counts from 1. */
1203 static bool
1205 {
1207 {
1218 }
1219 }
1221 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1222 constant. We assume ARG1 and ARG2 have the same data type, or at least
1223 are the same kind of constant and the same machine mode. Return zero if
1224 combining the constants is not allowed in the current operating mode. */
1226 static tree
1228 {
1229 /* Sanity check for the recursive cases. */
1237 {
1243 }
1246 {
1247 machine_mode mode;
1248 REAL_VALUE_TYPE d1;
1249 REAL_VALUE_TYPE d2;
1250 REAL_VALUE_TYPE value;
1251 REAL_VALUE_TYPE result;
1255 /* The following codes are handled by real_arithmetic. */
1257 {
1268 }
1276 /* Don't perform operation if we honor signaling NaNs and
1277 either operand is a signaling NaN. */
1283 /* Don't perform operation if it would raise a division
1284 by zero exception. */
1290 /* If either operand is a NaN, just return it. Otherwise, set up
1291 for floating-point trap; we return an overflow. */
1293 {
1294 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1295 is off. */
1299 }
1301 {
1302 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1303 is off. */
1307 }
1312 /* Don't constant fold this floating point operation if
1313 the result has overflowed and flag_trapping_math. */
1321 /* Don't constant fold this floating point operation if the
1322 result may dependent upon the run-time rounding mode and
1323 flag_rounding_math is set, or if GCC's software emulation
1324 is unable to accurately represent the result. */
1334 }
1337 {
1338 FIXED_VALUE_TYPE f1;
1339 FIXED_VALUE_TYPE f2;
1340 FIXED_VALUE_TYPE result;
1345 /* The following codes are handled by fixed_arithmetic. */
1347 {
1359 {
1366 }
1371 }
1378 /* Propagate overflow flags. */
1382 }
1385 {
1394 {
1405 mpc_mul);
1419 mpc_div);
1420 /* Fallthru. */
1426 {
1427 /* Keep this algorithm in sync with
1428 tree-complex.c:expand_complex_div_straight().
1430 Expand complex division to scalars, straightforward algorithm.
1431 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1432 t = br*br + bi*bi
1433 */
1434 tree magsquared
1438 tree t1
1442 tree t2
1449 }
1450 else
1451 {
1452 /* Keep this algorithm in sync with
1453 tree-complex.c:expand_complex_div_wide().
1455 Expand complex division to scalars, modified algorithm to minimize
1456 overflow with wide input ranges. */
1462 {
1463 /* In the TRUE branch, we compute
1464 ratio = br/bi;
1465 div = (br * ratio) + bi;
1466 tr = (ar * ratio) + ai;
1467 ti = (ai * ratio) - ar;
1468 tr = tr / div;
1469 ti = ti / div; */
1480 }
1481 else
1482 {
1483 /* In the FALSE branch, we compute
1484 ratio = d/c;
1485 divisor = (d * ratio) + c;
1486 tr = (b * ratio) + a;
1487 ti = b - (a * ratio);
1488 tr = tr / div;
1489 ti = ti / div; */
1501 }
1502 }
1507 }
1511 }
1517 {
1522 /* We can operate directly on the encoding if:
1524 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1525 implies
1526 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1528 Addition and subtraction are the supported operators
1529 for which this is true. */
1532 /* We can operate directly on stepped encodings if:
1534 a3 - a2 == a2 - a1
1535 implies:
1536 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1538 which is true if (x -> x op c) distributes over addition. */
1540 else
1541 /* Similarly in reverse. */
1543 tree_vector_builder elts;
1548 {
1554 /* It is possible that const_binop cannot handle the given
1555 code and return NULL_TREE */
1559 }
1562 }
1564 /* Shifts allow a scalar offset for a vector. */
1567 {
1570 tree_vector_builder elts;
1575 {
1580 /* It is possible that const_binop cannot handle the given
1581 code and return NULL_TREE. */
1585 }
1588 }
1590 }
1592 /* Overload that adds a TYPE parameter to be able to dispatch
1593 to fold_relational_const. */
1595 tree
1597 {
1601 /* ??? Until we make the const_binop worker take the type of the
1602 result as argument put those cases that need it here. */
1604 {
1621 {
1626 }
1632 {
1648 {
1653 ? NOP_EXPR
1660 }
1663 }
1669 {
1692 {
1705 }
1708 }
1711 }
1716 /* Make sure type and arg0 have the same saturating flag. */
1721 }
1723 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1724 Return zero if computing the constants is not possible. */
1726 tree
1728 {
1729 /* Don't perform the operation, other than NEGATE and ABS, if
1730 flag_signaling_nans is on and the operand is a signaling NaN. */
1740 {
1741 CASE_CONVERT:
1748 /* If the source address is 0, and the source address space
1749 cannot have a valid object at 0, fold to dest type null. */
1760 {
1761 /* Can't call fold_negate_const directly here as that doesn't
1762 handle all cases and we might not be able to negate some
1763 constants. */
1768 }
1778 {
1782 }
1790 /* Perform BIT_NOT_EXPR on each element individually. */
1792 {
1793 tree elem;
1795 /* This can cope with stepped encodings because ~x == -1 - x. */
1796 tree_vector_builder elements;
1800 {
1806 }
1809 }
1833 {
1856 else
1861 {
1867 }
1870 }
1879 }
1882 }
1884 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1885 indicates which particular sizetype to create. */
1887 tree
1889 {
1891 }
1892 \f
1893 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1894 is a tree code. The type of the result is taken from the operands.
1895 Both must be equivalent integer types, ala int_binop_types_match_p.
1896 If the operands are constant, so is the result. */
1898 tree
1900 {
1909 /* Handle the special case of two poly_int constants faster. */
1911 {
1912 /* And some specific cases even faster than that. */
1914 {
1921 }
1923 {
1927 }
1929 {
1933 }
1935 /* Handle general case of two integer constants. For sizetype
1936 constant calculations we always want to know about overflow,
1937 even in the unsigned case. */
1941 }
1944 }
1946 /* Given two values, either both of sizetype or both of bitsizetype,
1947 compute the difference between the two values. Return the value
1948 in signed type corresponding to the type of the operands. */
1950 tree
1952 {
1954 tree ctype;
1959 /* If the type is already signed, just do the simple thing. */
1967 else
1970 /* If either operand is not a constant, do the conversions to the signed
1971 type and subtract. The hardware will do the right thing with any
1972 overflow in the subtraction. */
1978 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1979 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1980 overflow) and negate (which can't either). Special-case a result
1981 of zero while we're here. */
1987 else
1991 MINUS_EXPR,
1993 }
1994 \f
1995 /* A subroutine of fold_convert_const handling conversions of an
1996 INTEGER_CST to another integer type. */
1998 static tree
2000 {
2001 /* Given an integer constant, make new constant with new type,
2002 appropriately sign-extended or truncated. Use widest_int
2003 so that any extension is done according ARG1's type. */
2007 }
2009 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2010 to an integer type. */
2012 static tree
2014 {
2016 tree t;
2018 /* The following code implements the floating point to integer
2019 conversion rules required by the Java Language Specification,
2020 that IEEE NaNs are mapped to zero and values that overflow
2021 the target precision saturate, i.e. values greater than
2022 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2023 are mapped to INT_MIN. These semantics are allowed by the
2024 C and C++ standards that simply state that the behavior of
2025 FP-to-integer conversion is unspecified upon overflow. */
2027 wide_int val;
2028 REAL_VALUE_TYPE r;
2032 {
2039 }
2041 /* If R is NaN, return zero and show we have an overflow. */
2043 {
2046 }
2048 /* See if R is less than the lower bound or greater than the
2049 upper bound. */
2052 {
2056 {
2059 }
2060 }
2063 {
2066 {
2069 {
2072 }
2073 }
2074 }
2081 }
2083 /* A subroutine of fold_convert_const handling conversions of a
2084 FIXED_CST to an integer type. */
2086 static tree
2088 {
2089 tree t;
2091 scalar_mode mode;
2093 /* Right shift FIXED_CST to temp by fbit. */
2097 {
2099 HOST_BITS_PER_DOUBLE_INT,
2102 /* Left shift temp to temp_trunc by fbit. */
2104 HOST_BITS_PER_DOUBLE_INT,
2106 }
2107 else
2108 {
2111 }
2113 /* If FIXED_CST is negative, we need to round the value toward 0.
2114 By checking if the fractional bits are not zero to add 1 to temp. */
2120 /* Given a fixed-point constant, make new constant with new type,
2121 appropriately sign-extended or truncated. */
2129 }
2131 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2132 to another floating point type. */
2134 static tree
2136 {
2137 REAL_VALUE_TYPE value;
2138 tree t;
2140 /* Don't perform the operation if flag_signaling_nans is on
2141 and the operand is a signaling NaN. */
2149 /* If converting an infinity or NAN to a representation that doesn't
2150 have one, set the overflow bit so that we can produce some kind of
2151 error message at the appropriate point if necessary. It's not the
2152 most user-friendly message, but it's better than nothing. */
2159 /* Regular overflow, conversion produced an infinity in a mode that
2160 can't represent them. */
2165 else
2168 }
2170 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2171 to a floating point type. */
2173 static tree
2175 {
2176 REAL_VALUE_TYPE value;
2177 tree t;
2185 }
2187 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2188 to another fixed-point type. */
2190 static tree
2192 {
2193 FIXED_VALUE_TYPE value;
2194 tree t;
2201 /* Propagate overflow flags. */
2205 }
2207 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2208 to a fixed-point type. */
2210 static tree
2212 {
2213 FIXED_VALUE_TYPE value;
2214 tree t;
2216 double_int di;
2223 else
2231 /* Propagate overflow flags. */
2235 }
2237 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2238 to a fixed-point type. */
2240 static tree
2242 {
2243 FIXED_VALUE_TYPE value;
2244 tree t;
2252 /* Propagate overflow flags. */
2256 }
2258 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2259 type TYPE. If no simplification can be done return NULL_TREE. */
2261 static tree
2263 {
2268 /* We can't widen types, since the runtime value could overflow the
2269 original type before being extended to the new type. */
2280 {
2287 }
2289 {
2296 }
2298 {
2305 }
2307 {
2310 {
2313 /* We can't handle steps directly when extending, since the
2314 values need to wrap at the original precision first. */
2315 bool step_ok_p
2319 tree_vector_builder v;
2324 {
2330 }
2332 }
2333 }
2335 }
2337 /* Construct a vector of zero elements of vector type TYPE. */
2339 static tree
2341 {
2342 tree t;
2346 }
2348 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2350 bool
2352 {
2367 {
2384 }
2385 }
2387 /* Convert expression ARG to type TYPE. Used by the middle-end for
2388 simple conversions in preference to calling the front-end's convert. */
2390 tree
2392 {
2394 tree tem;
2405 {
2408 /* Handle conversions between pointers to different address spaces. */
2413 /* fall through */
2418 {
2422 }
2436 {
2440 }
2442 {
2446 }
2448 {
2452 }
2455 {
2473 }
2478 {
2482 }
2485 {
2499 }
2503 {
2512 integer_zero_node));
2514 {
2518 {
2524 }
2532 }
2536 }
2554 }
2555 fold_convert_exit:
2558 }
2559 \f
2560 /* Return false if expr can be assumed not to be an lvalue, true
2561 otherwise. */
2563 static bool
2565 {
2566 /* We only need to wrap lvalue tree codes. */
2568 {
2599 /* Assume the worst for front-end tree codes. */
2603 }
2606 }
2608 /* Return an expr equal to X but certainly not valid as an lvalue. */
2610 tree
2612 {
2613 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2614 us. */
2621 }
2623 /* When pedantic, return an expr equal to X but certainly not valid as a
2624 pedantic lvalue. Otherwise, return X. */
2626 static tree
2628 {
2630 }
2631 \f
2632 /* Given a tree comparison code, return the code that is the logical inverse.
2633 It is generally not safe to do this for floating-point comparisons, except
2634 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2635 ERROR_MARK in this case. */
2637 enum tree_code
2639 {
2645 {
2676 }
2677 }
2679 /* Similar, but return the comparison that results if the operands are
2680 swapped. This is safe for floating-point. */
2682 enum tree_code
2684 {
2686 {
2712 }
2713 }
2716 /* Convert a comparison tree code from an enum tree_code representation
2717 into a compcode bit-based encoding. This function is the inverse of
2718 compcode_to_comparison. */
2720 static enum comparison_code
2722 {
2724 {
2755 }
2756 }
2758 /* Convert a compcode bit-based encoding of a comparison operator back
2759 to GCC's enum tree_code representation. This function is the
2760 inverse of comparison_to_compcode. */
2762 static enum tree_code
2764 {
2766 {
2797 }
2798 }
2800 /* Return true if COND1 tests the opposite condition of COND2. */
2802 bool
2804 {
2807 && (invert_tree_comparison
2814 }
2816 /* Return a tree for the comparison which is the combination of
2817 doing the AND or OR (depending on CODE) of the two operations LCODE
2818 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2819 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2820 if this makes the transformation invalid. */
2822 tree
2827 {
2834 {
2845 }
2848 {
2849 /* Eliminate unordered comparisons, as well as LTGT and ORD
2850 which are not used unless the mode has NaNs. */
2856 }
2858 {
2859 /* Check that the original operation and the optimized ones will trap
2860 under the same condition. */
2871 /* In a short-circuited boolean expression the LHS might be
2872 such that the RHS, if evaluated, will never trap. For
2873 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2874 if neither x nor y is NaN. (This is a mixed blessing: for
2875 example, the expression above will never trap, hence
2876 optimizing it to x < y would be invalid). */
2881 /* If the comparison was short-circuited, and only the RHS
2882 trapped, we may now generate a spurious trap. */
2887 /* If we changed the conditions that cause a trap, we lose. */
2890 }
2896 else
2897 {
2902 }
2903 }
2904 \f
2905 /* Return nonzero if two operands (typically of the same tree node)
2906 are necessarily equal. FLAGS modifies behavior as follows:
2908 If OEP_ONLY_CONST is set, only return nonzero for constants.
2909 This function tests whether the operands are indistinguishable;
2910 it does not test whether they are equal using C's == operation.
2911 The distinction is important for IEEE floating point, because
2912 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2913 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2915 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2916 even though it may hold multiple values during a function.
2917 This is because a GCC tree node guarantees that nothing else is
2918 executed between the evaluation of its "operands" (which may often
2919 be evaluated in arbitrary order). Hence if the operands themselves
2920 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2921 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2922 unset means assuming isochronic (or instantaneous) tree equivalence.
2923 Unless comparing arbitrary expression trees, such as from different
2924 statements, this flag can usually be left unset.
2926 If OEP_PURE_SAME is set, then pure functions with identical arguments
2927 are considered the same. It is used when the caller has other ways
2928 to ensure that global memory is unchanged in between.
2930 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2931 not values of expressions.
2933 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2934 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2936 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2937 any operand with side effect. This is unnecesarily conservative in the
2938 case we know that arg0 and arg1 are in disjoint code paths (such as in
2939 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2940 addresses with TREE_CONSTANT flag set so we know that &var == &var
2941 even if var is volatile. */
2943 bool
2946 {
2954 /* If either is ERROR_MARK, they aren't equal. */
2960 /* Similar, if either does not have a type (like a template id),
2961 they aren't equal. */
2965 /* We cannot consider pointers to different address space equal. */
2972 /* Check equality of integer constants before bailing out due to
2973 precision differences. */
2975 {
2976 /* Address of INTEGER_CST is not defined; check that we did not forget
2977 to drop the OEP_ADDRESS_OF flags. */
2980 }
2983 {
2984 /* If both types don't have the same signedness, then we can't consider
2985 them equal. We must check this before the STRIP_NOPS calls
2986 because they may change the signedness of the arguments. As pointers
2987 strictly don't have a signedness, require either two pointers or
2988 two non-pointers as well. */
2994 /* If both types don't have the same precision, then it is not safe
2995 to strip NOPs. */
3002 }
3003 #if 0
3004 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3005 sanity check once the issue is solved. */
3006 else
3007 /* Addresses of conversions and SSA_NAMEs (and many other things)
3008 are not defined. Check that we did not forget to drop the
3009 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3012 #endif
3014 /* In case both args are comparisons but with different comparison
3015 code, try to swap the comparison operands of one arg to produce
3016 a match and compare that variant. */
3020 {
3028 }
3031 {
3032 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3034 ;
3036 {
3037 /* If we are interested in comparing addresses ignore
3038 MEM_REF wrappings of the base that can appear just for
3039 TBAA reasons. */
3053 }
3054 else
3056 }
3058 /* When not checking adddresses, this is needed for conversions and for
3059 COMPONENT_REF. Might as well play it safe and always test this. */
3066 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3067 We don't care about side effects in that case because the SAVE_EXPR
3068 takes care of that for us. In all other cases, two expressions are
3069 equal if they have no side effects. If we have two identical
3070 expressions with side effects that should be treated the same due
3071 to the only side effects being identical SAVE_EXPR's, that will
3072 be detected in the recursive calls below.
3073 If we are taking an invariant address of two identical objects
3074 they are necessarily equal as well. */
3081 /* Next handle constant cases, those for which we can return 1 even
3082 if ONLY_CONST is set. */
3085 {
3099 {
3100 /* If we do not distinguish between signed and unsigned zero,
3101 consider them equal. */
3104 }
3108 {
3123 }
3127 flags)
3129 flags));
3140 flags | OEP_ADDRESS_OF
3143 /* In GIMPLE empty constructors are allowed in initializers of
3144 aggregates. */
3148 }
3153 /* Define macros to test an operand from arg0 and arg1 for equality and a
3154 variant that allows null and views null as being different from any
3155 non-null value. In the latter case, if either is null, the both
3156 must be; otherwise, do the normal comparison. */
3157 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3158 TREE_OPERAND (arg1, N), flags)
3160 #define OP_SAME_WITH_NULL(N) \
3161 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3162 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3165 {
3167 /* Two conversions are equal only if signedness and modes match. */
3169 {
3170 CASE_CONVERT:
3178 }
3188 /* For commutative ops, allow the other order. */
3196 /* If either of the pointer (or reference) expressions we are
3197 dereferencing contain a side effect, these cannot be equal,
3198 but their addresses can be. */
3205 {
3208 {
3212 /* Verify that the access types are compatible. */
3216 }
3221 /* Require the same offset. */
3227 /* Fallthru. */
3235 {
3236 /* Require equal access sizes */
3242 flags)))
3244 /* Verify that access happens in similar types. */
3247 /* Verify that accesses are TBAA compatible. */
3256 /* Verify that alignment is compatible. */
3260 }
3263 /* TARGET_MEM_REF require equal extra operands. */
3274 /* Compare the array index by value if it is constant first as we
3275 may have different types but same value here. */
3281 /* Compare low bound and element size as with OEP_ADDRESS_OF
3282 we have to account for the offset of the ref. */
3287 array_ref_low_bound
3291 array_ref_element_size
3293 flags))));
3296 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3297 may be NULL when we're called to compare MEM_EXPRs. */
3310 /* Virtual table call. */
3312 {
3326 }
3330 }
3334 {
3336 /* Be sure we pass right ADDRESS_OF flag. */
3353 /* The multiplcation operands are commutative. */
3354 /* FALLTHRU */
3362 /* Otherwise take into account this is a commutative operation. */
3375 /* BIT_INSERT_EXPR has an implict operand as the type precision
3376 of op1. Need to check to make sure they are the same. */
3382 /* FALLTHRU */
3408 }
3412 {
3416 /* If not both CALL_EXPRs are either internal or normal function
3417 functions, then they are not equal. */
3420 {
3421 /* If the CALL_EXPRs call different internal functions, then they
3422 are not equal. */
3425 }
3426 else
3427 {
3428 /* If the CALL_EXPRs call different functions, then they are not
3429 equal. */
3431 flags))
3433 }
3435 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3436 {
3440 else
3444 }
3446 /* Now see if all the arguments are the same. */
3447 {
3458 /* If we get here and both argument lists are exhausted
3459 then the CALL_EXPRs are equal. */
3461 }
3464 }
3467 /* Consider __builtin_sqrt equal to sqrt. */
3476 {
3480 /* In GIMPLE constructors are used only to build vectors from
3481 elements. Individual elements in the constructor must be
3482 indexed in increasing order and form an initial sequence.
3484 We make no effort to compare constructors in generic.
3485 (see sem_variable::equals in ipa-icf which can do so for
3486 constants). */
3491 /* Be sure that vectors constructed have the same representation.
3492 We only tested element precision and modes to match.
3493 Vectors may be BLKmode and thus also check that the number of
3494 parts match. */
3507 {
3512 /* In GIMPLE the indexes can be either NULL or matching i.
3513 Double check this so we won't get false
3514 positives for GENERIC. */
3522 }
3524 }
3527 {
3528 /* Compare the STATEMENT_LISTs. */
3534 {
3535 /* The lists don't have the same number of statements. */
3541 flags & (OEP_LEXICOGRAPHIC
3544 }
3545 }
3550 {
3561 }
3565 }
3567 #undef OP_SAME
3568 #undef OP_SAME_WITH_NULL
3569 }
3571 /* Generate a hash value for an expression. This can be used iteratively
3572 by passing a previous result as the HSTATE argument. */
3574 void
3577 {
3583 {
3586 }
3596 {
3597 /* Alas, constants aren't shared, so we can't rely on pointer
3598 identity. */
3608 {
3612 else
3616 }
3618 {
3622 }
3632 {
3639 }
3641 /* We can just compare by pointer. */
3645 /* The node itself doesn't matter. */
3649 /* Ignore. */
3652 /* A list of expressions, for a CALL_EXPR or as the elements of a
3653 VECTOR_CST. */
3658 {
3664 {
3665 /* In GIMPLE the indexes can be either NULL or matching i. */
3670 }
3672 }
3674 {
3675 tree_stmt_iterator i;
3680 }
3689 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3690 Otherwise nodes that compare equal according to operand_equal_p might
3691 get different hash codes. However, don't do this for machine specific
3692 or front end builtins, since the function code is overloaded in those
3693 cases. */
3696 {
3699 }
3700 /* FALL THROUGH */
3703 {
3707 }
3711 {
3712 /* DECL's have a unique ID */
3714 }
3716 {
3717 /* For comparisons that can be swapped, use the lower
3718 tree code. */
3725 }
3727 {
3728 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3729 operand_equal_p. */
3733 /* Don't hash the type, that can lead to having nodes which
3734 compare equal according to operand_equal_p, but which
3735 have different hash codes. Make sure to include signedness
3736 in the hash computation. */
3739 }
3740 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3748 /* Don't ICE on FE specific trees, or their arguments etc.
3749 during operand_equal_p hash verification. */
3752 else
3753 {
3759 {
3786 {
3787 /* The multiplication operands are commutative. */
3794 }
3802 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3803 Usually different TARGET_EXPRs just should use
3804 different temporaries in their slots. */
3808 /* Virtual table call. */
3816 }
3818 /* Don't hash the type, that can lead to having nodes which
3819 compare equal according to operand_equal_p, but which
3820 have different hash codes. */
3822 {
3823 /* Make sure to include signness in the hash computation. */
3826 }
3829 {
3830 /* It's a commutative expression. We want to hash it the same
3831 however it appears. We do this by first hashing both operands
3832 and then rehashing based on the order of their independent
3833 hashes. */
3838 }
3839 else
3843 }
3845 }
3846 }
3848 bool
3851 {
3852 /* When checking, verify at the outermost operand_equal_p call that
3853 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
3854 hash value. */
3856 {
3858 {
3860 {
3867 }
3869 }
3870 else
3874 }
3877 }
3882 /* Conveinece wrapper around operand_compare class because usually we do
3883 not need to play with the valueizer. */
3885 bool
3887 {
3889 }
3891 namespace inchash
3892 {
3894 /* Generate a hash value for an expression. This can be used iteratively
3895 by passing a previous result as the HSTATE argument.
3897 This function is intended to produce the same hash for expressions which
3898 would compare equal using operand_equal_p. */
3899 void
3901 {
3903 }
3905 }
3906 \f
3907 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3908 with a different signedness or a narrower precision. */
3910 static bool
3912 {
3920 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3921 and see if the inner values are the same. This removes any
3922 signedness comparison, which doesn't matter here. */
3930 /* Discard a single widening conversion from ARG1 and see if the inner
3931 value is the same as ARG0. */
3940 }
3941 \f
3942 /* See if ARG is an expression that is either a comparison or is performing
3943 arithmetic on comparisons. The comparisons must only be comparing
3944 two different values, which will be stored in *CVAL1 and *CVAL2; if
3945 they are nonzero it means that some operands have already been found.
3946 No variables may be used anywhere else in the expression except in the
3947 comparisons.
3949 If this is true, return 1. Otherwise, return zero. */
3951 static bool
3953 {
3957 /* We can handle some of the tcc_expression cases here. */
3966 {
3985 /* First see if we can handle the first operand, then the second. For
3986 the second operand, we know *CVAL1 can't be zero. It must be that
3987 one side of the comparison is each of the values; test for the
3988 case where this isn't true by failing if the two operands
3989 are the same. */
3998 ;
4002 ;
4003 else
4007 ;
4011 ;
4012 else
4019 }
4020 }
4021 \f
4022 /* ARG is a tree that is known to contain just arithmetic operations and
4023 comparisons. Evaluate the operations in the tree substituting NEW0 for
4024 any occurrence of OLD0 as an operand of a comparison and likewise for
4025 NEW1 and OLD1. */
4027 static tree
4030 {
4035 /* We can handle some of the tcc_expression cases here. */
4043 {
4058 {
4077 }
4078 /* Fall through - ??? */
4081 {
4085 /* We need to check both for exact equality and tree equality. The
4086 former will be true if the operand has a side-effect. In that
4087 case, we know the operand occurred exactly once. */
4100 }
4104 }
4105 }
4106 \f
4107 /* Return a tree for the case when the result of an expression is RESULT
4108 converted to TYPE and OMITTED was previously an operand of the expression
4109 but is now not needed (e.g., we folded OMITTED * 0).
4111 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4112 the conversion of RESULT to TYPE. */
4114 tree
4116 {
4119 /* If the resulting operand is an empty statement, just return the omitted
4120 statement casted to void. */
4130 }
4132 /* Return a tree for the case when the result of an expression is RESULT
4133 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4134 of the expression but are now not needed.
4136 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4137 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4138 evaluated before OMITTED2. Otherwise, if neither has side effects,
4139 just do the conversion of RESULT to TYPE. */
4141 tree
4144 {
4153 }
4155 \f
4156 /* Return a simplified tree node for the truth-negation of ARG. This
4157 never alters ARG itself. We assume that ARG is an operation that
4158 returns a truth value (0 or 1).
4160 FIXME: one would think we would fold the result, but it causes
4161 problems with the dominator optimizer. */
4163 static tree
4165 {
4170 /* If this is a comparison, we can simply invert it, except for
4171 floating-point non-equality comparisons, in which case we just
4172 enclose a TRUTH_NOT_EXPR around what we have. */
4175 {
4178 && flag_trapping_math
4192 }
4195 {
4214 /* Here we can invert either operand. We invert the first operand
4215 unless the second operand is a TRUTH_NOT_EXPR in which case our
4216 result is the XOR of the first operand with the inside of the
4217 negation of the second operand. */
4222 else
4245 {
4252 /* A COND_EXPR may have a throw as one operand, which
4253 then has void type. Just leave void operands
4254 as they are. */
4260 }
4272 CASE_CONVERT:
4276 /* fall through */
4298 }
4299 }
4301 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4302 assume that ARG is an operation that returns a truth value (0 or 1
4303 for scalars, 0 or -1 for vectors). Return the folded expression if
4304 folding is successful. Otherwise, return NULL_TREE. */
4306 static tree
4308 {
4311 ? BIT_NOT_EXPR
4314 }
4316 /* Return a simplified tree node for the truth-negation of ARG. This
4317 never alters ARG itself. We assume that ARG is an operation that
4318 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4320 tree
4322 {
4328 ? BIT_NOT_EXPR
4331 }
4332 \f
4333 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4334 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4335 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4336 is the original memory reference used to preserve the alias set of
4337 the access. */
4339 static tree
4343 {
4346 /* Attempt not to lose the access path if possible. */
4348 {
4350 machine_mode nmode;
4352 tree noffset;
4360 && !reversep
4361 && !nreversep
4363 {
4366 }
4367 }
4376 {
4383 }
4398 }
4400 /* Optimize a bit-field compare.
4402 There are two cases: First is a compare against a constant and the
4403 second is a comparison of two items where the fields are at the same
4404 bit position relative to the start of a chunk (byte, halfword, word)
4405 large enough to contain it. In these cases we can avoid the shift
4406 implicit in bitfield extractions.
4408 For constants, we emit a compare of the shifted constant with the
4409 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4410 compared. For two fields at the same position, we do the ANDs with the
4411 similar mask and compare the result of the ANDs.
4413 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4414 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4415 are the left and right operands of the comparison, respectively.
4417 If the optimization described above can be done, we return the resulting
4418 tree. Otherwise we return zero. */
4420 static tree
4423 {
4427 tree unsigned_type;
4430 scalar_int_mode nmode;
4435 tree mask;
4436 tree offset;
4438 /* Get all the information about the extractions being done. If the bit size
4439 is the same as the size of the underlying object, we aren't doing an
4440 extraction at all and so can do nothing. We also don't want to
4441 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4442 then will no longer be able to replace it. */
4457 else
4458 {
4459 /* If this is not a constant, we can only do something if bit positions,
4460 sizes, signedness and storage order are the same. */
4461 rinner
4474 }
4476 /* Honor the C++ memory model and mimic what RTL expansion does. */
4480 {
4484 }
4486 /* See if we can find a mode to refer to this field. We should be able to,
4487 but fail if we can't. */
4495 /* Set signed and unsigned types of the precision of this mode for the
4496 shifts below. */
4499 /* Compute the bit position and size for the new reference and our offset
4500 within it. If the new reference is the same size as the original, we
4501 won't optimize anything, so return zero. */
4511 /* Make the mask to be used against the extracted field. */
4518 {
4522 /* If not comparing with constant, just rework the comparison
4523 and return. */
4531 }
4533 /* Otherwise, we are handling the constant case. See if the constant is too
4534 big for the field. Warn and return a tree for 0 (false) if so. We do
4535 this not only for its own sake, but to avoid having to test for this
4536 error case below. If we didn't, we might generate wrong code.
4538 For unsigned fields, the constant shifted right by the field length should
4539 be all zero. For signed fields, the high-order bits should agree with
4540 the sign bit. */
4543 {
4545 {
4549 }
4550 }
4551 else
4552 {
4555 {
4559 }
4560 }
4565 /* Single-bit compares should always be against zero. */
4567 {
4570 }
4572 /* Make a new bitfield reference, shift the constant over the
4573 appropriate number of bits and mask it with the computed mask
4574 (in case this was a signed field). If we changed it, make a new one. */
4582 mask);
4587 }
4588 \f
4589 /* Subroutine for fold_truth_andor_1: decode a field reference.
4591 If EXP is a comparison reference, we return the innermost reference.
4593 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4594 set to the starting bit number.
4596 If the innermost field can be completely contained in a mode-sized
4597 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4599 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4600 otherwise it is not changed.
4602 *PUNSIGNEDP is set to the signedness of the field.
4604 *PREVERSEP is set to the storage order of the field.
4606 *PMASK is set to the mask used. This is either contained in a
4607 BIT_AND_EXPR or derived from the width of the field.
4609 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4611 Return 0 if this is not a component reference or is one that we can't
4612 do anything with. */
4614 static tree
4619 {
4624 tree unsigned_type;
4627 /* All the optimizations using this function assume integer fields.
4628 There are problems with FP fields since the type_for_size call
4629 below can fail for, e.g., XFmode. */
4633 /* We are interested in the bare arrangement of bits, so strip everything
4634 that doesn't affect the machine mode. However, record the type of the
4635 outermost expression if it may matter below. */
4642 {
4648 }
4659 /* Reject out-of-bound accesses (PR79731). */
4671 /* If the number of bits in the reference is the same as the bitsize of
4672 the outer type, then the outer type gives the signedness. Otherwise
4673 (in case of a small bitfield) the signedness is unchanged. */
4677 /* Compute the mask to access the bitfield. */
4685 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4693 }
4695 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4696 bit positions and MASK is SIGNED. */
4698 static bool
4700 {
4704 /* If this function returns true when the type of the mask is
4705 UNSIGNED, then there will be errors. In particular see
4706 gcc.c-torture/execute/990326-1.c. There does not appear to be
4707 any documentation paper trail as to why this is so. But the pre
4708 wide-int worked with that restriction and it has been preserved
4709 here. */
4714 }
4716 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4717 represents the sign bit of EXP's type. If EXP represents a sign
4718 or zero extension, also test VAL against the unextended type.
4719 The return value is the (sub)expression whose sign bit is VAL,
4720 or NULL_TREE otherwise. */
4722 tree
4724 {
4726 tree t;
4728 /* Tree EXP must have an integral type. */
4733 /* Tree VAL must be an integer constant. */
4742 /* Handle extension from a narrower type. */
4748 }
4750 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4751 to be evaluated unconditionally. */
4753 static bool
4755 {
4756 /* Strip any conversions that don't change the machine mode. */
4765 /* Don't regard global variables as simple. They may be
4766 allocated in ways unknown to the compiler (shared memory,
4767 #pragma weak, etc). */
4770 /* Weakrefs are not safe to be read, since they can be NULL.
4771 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4772 have DECL_WEAK flag set. */
4774 /* Loading a static variable is unduly expensive, but global
4775 registers aren't expensive. */
4777 }
4779 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4780 to be evaluated unconditionally.
4781 I addition to simple_operand_p, we assume that comparisons, conversions,
4782 and logic-not operations are simple, if their operands are simple, too. */
4784 static bool
4786 {
4805 }
4807 \f
4808 /* The following functions are subroutines to fold_range_test and allow it to
4809 try to change a logical combination of comparisons into a range test.
4811 For example, both
4812 X == 2 || X == 3 || X == 4 || X == 5
4813 and
4814 X >= 2 && X <= 5
4815 are converted to
4816 (unsigned) (X - 2) <= 3
4818 We describe each set of comparisons as being either inside or outside
4819 a range, using a variable named like IN_P, and then describe the
4820 range with a lower and upper bound. If one of the bounds is omitted,
4821 it represents either the highest or lowest value of the type.
4823 In the comments below, we represent a range by two numbers in brackets
4824 preceded by a "+" to designate being inside that range, or a "-" to
4825 designate being outside that range, so the condition can be inverted by
4826 flipping the prefix. An omitted bound is represented by a "-". For
4827 example, "- [-, 10]" means being outside the range starting at the lowest
4828 possible value and ending at 10, in other words, being greater than 10.
4829 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4830 always false.
4832 We set up things so that the missing bounds are handled in a consistent
4833 manner so neither a missing bound nor "true" and "false" need to be
4834 handled using a special case. */
4836 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4837 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4838 and UPPER1_P are nonzero if the respective argument is an upper bound
4839 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4840 must be specified for a comparison. ARG1 will be converted to ARG0's
4841 type if both are specified. */
4843 static tree
4846 {
4847 tree tem;
4851 /* If neither arg represents infinity, do the normal operation.
4852 Else, if not a comparison, return infinity. Else handle the special
4853 comparison rules. Note that most of the cases below won't occur, but
4854 are handled for consistency. */
4857 {
4862 }
4867 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4868 for neither. In real maths, we cannot assume open ended ranges are
4869 the same. But, this is computer arithmetic, where numbers are finite.
4870 We can therefore make the transformation of any unbounded range with
4871 the value Z, Z being greater than any representable number. This permits
4872 us to treat unbounded ranges as equal. */
4876 {
4897 }
4900 }
4901 \f
4902 /* Helper routine for make_range. Perform one step for it, return
4903 new expression if the loop should continue or NULL_TREE if it should
4904 stop. */
4906 tree
4910 {
4916 {
4918 /* We can only do something if the range is testing for zero. */
4927 /* We can only do something if the range is testing for zero
4928 and if the second operand is an integer constant. Note that
4929 saying something is "in" the range we make is done by
4930 complementing IN_P since it will set in the initial case of
4931 being not equal to zero; "out" is leaving it alone. */
4938 {
4959 }
4961 /* If this is an unsigned comparison, we also know that EXP is
4962 greater than or equal to zero. We base the range tests we make
4963 on that fact, so we record it here so we can parse existing
4964 range tests. We test arg0_type since often the return type
4965 of, e.g. EQ_EXPR, is boolean. */
4967 {
4971 NULL_TREE))
4976 /* If the high bound is missing, but we have a nonzero low
4977 bound, reverse the range so it goes from zero to the low bound
4978 minus 1. */
4980 {
4985 }
4986 }
4994 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4995 low and high are non-NULL, then normalize will DTRT. */
4998 {
5003 }
5005 /* (-x) IN [a,b] -> x in [-b, -a] */
5017 /* ~ X -> -X - 1 */
5026 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5027 move a constant to the other side. */
5032 /* If EXP is signed, any overflow in the computation is undefined,
5033 so we don't worry about it so long as our computations on
5034 the bounds don't overflow. For unsigned, overflow is defined
5035 and this is exactly the right thing. */
5047 normalize:
5048 /* Check for an unsigned range which has wrapped around the maximum
5049 value thus making n_high < n_low, and normalize it. */
5051 {
5057 /* If the range is of the form +/- [ x+1, x ], we won't
5058 be able to normalize it. But then, it represents the
5059 whole range or the empty set, so make it
5060 +/- [ -, - ]. */
5064 else
5066 }
5067 else
5075 CASE_CONVERT:
5093 /* If we're converting arg0 from an unsigned type, to exp,
5094 a signed type, we will be doing the comparison as unsigned.
5095 The tests above have already verified that LOW and HIGH
5096 are both positive.
5098 So we have to ensure that we will handle large unsigned
5099 values the same way that the current signed bounds treat
5100 negative values. */
5103 {
5104 tree high_positive;
5105 tree equiv_type;
5106 /* For fixed-point modes, we need to pass the saturating flag
5107 as the 2nd parameter. */
5109 equiv_type
5112 else
5113 equiv_type
5116 /* A range without an upper bound is, naturally, unbounded.
5117 Since convert would have cropped a very large value, use
5118 the max value for the destination type. */
5119 high_positive
5126 high_positive),
5129 /* If the low bound is specified, "and" the range with the
5130 range for which the original unsigned value will be
5131 positive. */
5133 {
5136 integer_zero_node),
5137 high_positive))
5141 }
5142 else
5143 {
5144 /* Otherwise, "or" the range with the range of the input
5145 that will be interpreted as negative. */
5148 integer_zero_node),
5149 high_positive))
5153 }
5154 }
5163 }
5164 }
5166 /* Given EXP, a logical expression, set the range it is testing into
5167 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5168 actually being tested. *PLOW and *PHIGH will be made of the same
5169 type as the returned expression. If EXP is not a comparison, we
5170 will most likely not be returning a useful value and range. Set
5171 *STRICT_OVERFLOW_P to true if the return value is only valid
5172 because signed overflow is undefined; otherwise, do not change
5173 *STRICT_OVERFLOW_P. */
5175 tree
5178 {
5186 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5187 and see if we can refine the range. Some of the cases below may not
5188 happen, but it doesn't seem worth worrying about this. We "continue"
5189 the outer loop when we've changed something; otherwise we "break"
5190 the switch, which will "break" the while. */
5196 {
5202 {
5210 }
5219 }
5221 /* If EXP is a constant, we can evaluate whether this is true or false. */
5223 {
5230 }
5234 }
5236 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5237 a bitwise check i.e. when
5238 LOW == 0xXX...X00...0
5239 HIGH == 0xXX...X11...1
5240 Return corresponding mask in MASK and stem in VALUE. */
5242 static bool
5245 {
5268 }
5269 \f
5270 /* Helper routine for build_range_check and match.pd. Return the type to
5271 perform the check or NULL if it shouldn't be optimized. */
5273 tree
5275 {
5276 /* First make sure that arithmetics in this type is valid, then make sure
5277 that it wraps around. */
5282 {
5285 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5286 for the type in question, as we rely on this here. */
5296 else
5298 }
5302 }
5304 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5305 type, TYPE, return an expression to test if EXP is in (or out of, depending
5306 on IN_P) the range. Return 0 if the test couldn't be created. */
5308 tree
5311 {
5314 /* Disable this optimization for function pointer expressions
5315 on targets that require function pointer canonicalization. */
5322 {
5328 }
5350 value);
5353 {
5355 {
5359 }
5361 }
5363 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5365 {
5369 {
5371 {
5374 etype
5376 else
5379 }
5382 }
5383 }
5385 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5386 This requires wrap-around arithmetics for the type of the expression. */
5403 }
5404 \f
5405 /* Return the predecessor of VAL in its type, handling the infinite case. */
5407 static tree
5409 {
5415 else
5418 }
5420 /* Return the successor of VAL in its type, handling the infinite case. */
5422 static tree
5424 {
5430 else
5433 }
5435 /* Given two ranges, see if we can merge them into one. Return 1 if we
5436 can, 0 if we can't. Set the output range into the specified parameters. */
5438 bool
5441 {
5445 tree tem;
5455 /* Make range 0 be the range that starts first, or ends last if they
5456 start at the same value. Swap them if it isn't. */
5459 || (lowequal
5462 {
5466 }
5468 /* If the second range is != high1 where high1 is the type maximum of
5469 the type, try first merging with < high1 range. */
5471 && high1
5478 {
5483 /* Similarly for the second range != low1 where low1 is the type minimum
5484 of the type, try first merging with > low1 range. */
5489 }
5491 /* Now flag two cases, whether the ranges are disjoint or whether the
5492 second range is totally subsumed in the first. Note that the tests
5493 below are simplified by the ones above. */
5499 /* We now have four cases, depending on whether we are including or
5500 excluding the two ranges. */
5502 {
5503 /* If they don't overlap, the result is false. If the second range
5504 is a subset it is the result. Otherwise, the range is from the start
5505 of the second to the end of the first. */
5510 else
5512 }
5515 {
5516 /* If they don't overlap, the result is the first range. If they are
5517 equal, the result is false. If the second range is a subset of the
5518 first, and the ranges begin at the same place, we go from just after
5519 the end of the second range to the end of the first. If the second
5520 range is not a subset of the first, or if it is a subset and both
5521 ranges end at the same place, the range starts at the start of the
5522 first range and ends just before the second range.
5523 Otherwise, we can't describe this as a single range. */
5529 {
5534 {
5535 /* We are in the weird situation where high0 > high1 but
5536 high1 has no successor. Punt. */
5538 }
5539 }
5541 {
5546 {
5547 /* low0 < low1 but low1 has no predecessor. Punt. */
5549 }
5550 }
5551 else
5553 }
5556 {
5557 /* If they don't overlap, the result is the second range. If the second
5558 is a subset of the first, the result is false. Otherwise,
5559 the range starts just after the first range and ends at the
5560 end of the second. */
5565 else
5566 {
5571 {
5572 /* high1 > high0 but high0 has no successor. Punt. */
5574 }
5575 }
5576 }
5578 else
5579 {
5580 /* The case where we are excluding both ranges. Here the complex case
5581 is if they don't overlap. In that case, the only time we have a
5582 range is if they are adjacent. If the second is a subset of the
5583 first, the result is the first. Otherwise, the range to exclude
5584 starts at the beginning of the first range and ends at the end of the
5585 second. */
5587 {
5592 else
5593 {
5594 /* Canonicalize - [min, x] into - [-, x]. */
5597 {
5600 GET_MODE_BITSIZE
5603 /* FALLTHROUGH */
5616 }
5618 /* Canonicalize - [x, max] into - [x, -]. */
5621 {
5624 GET_MODE_BITSIZE
5627 /* FALLTHROUGH */
5643 }
5645 /* The ranges might be also adjacent between the maximum and
5646 minimum values of the given type. For
5647 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5648 return + [x + 1, y - 1]. */
5650 {
5657 }
5658 else
5660 }
5661 }
5664 else
5666 }
5670 }
5671 \f
5673 /* Subroutine of fold, looking inside expressions of the form
5674 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5675 of the COND_EXPR. This function is being used also to optimize
5676 A op B ? C : A, by reversing the comparison first.
5678 Return a folded expression whose code is not a COND_EXPR
5679 anymore, or NULL_TREE if no folding opportunity is found. */
5681 static tree
5684 {
5689 tree tem;
5694 /* If we have A op 0 ? A : -A, consider applying the following
5695 transformations:
5697 A == 0? A : -A same as -A
5698 A != 0? A : -A same as A
5699 A >= 0? A : -A same as abs (A)
5700 A > 0? A : -A same as abs (A)
5701 A <= 0? A : -A same as -abs (A)
5702 A < 0? A : -A same as -abs (A)
5704 None of these transformations work for modes with signed
5705 zeros. If A is +/-0, the first two transformations will
5706 change the sign of the result (from +0 to -0, or vice
5707 versa). The last four will fix the sign of the result,
5708 even though the original expressions could be positive or
5709 negative, depending on the sign of A.
5711 Note that all these transformations are correct if A is
5712 NaN, since the two alternatives (A and -A) are also NaNs. */
5719 /* In the case that A is of the form X-Y, '-A' (arg2) may
5720 have already been folded to Y-X, check for that. */
5728 {
5740 /* Fall through. */
5751 /* FALLTHRU */
5761 }
5763 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5764 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5765 both transformations are correct when A is NaN: A != 0
5766 is then true, and A == 0 is false. */
5770 {
5775 }
5777 /* Try some transformations of A op B ? A : B.
5779 A == B? A : B same as B
5780 A != B? A : B same as A
5781 A >= B? A : B same as max (A, B)
5782 A > B? A : B same as max (B, A)
5783 A <= B? A : B same as min (A, B)
5784 A < B? A : B same as min (B, A)
5786 As above, these transformations don't work in the presence
5787 of signed zeros. For example, if A and B are zeros of
5788 opposite sign, the first two transformations will change
5789 the sign of the result. In the last four, the original
5790 expressions give different results for (A=+0, B=-0) and
5791 (A=-0, B=+0), but the transformed expressions do not.
5793 The first two transformations are correct if either A or B
5794 is a NaN. In the first transformation, the condition will
5795 be false, and B will indeed be chosen. In the case of the
5796 second transformation, the condition A != B will be true,
5797 and A will be chosen.
5799 The conversions to max() and min() are not correct if B is
5800 a number and A is not. The conditions in the original
5801 expressions will be false, so all four give B. The min()
5802 and max() versions would give a NaN instead. */
5805 /* Avoid these transformations if the COND_EXPR may be used
5806 as an lvalue in the C++ front-end. PR c++/19199. */
5807 && (in_gimple_form
5813 {
5819 {
5828 /* In C++ a ?: expression can be an lvalue, so put the
5829 operand which will be used if they are equal first
5830 so that we can convert this back to the
5831 corresponding COND_EXPR. */
5833 {
5841 }
5848 {
5856 }
5869 }
5870 }
5873 }
5876 \f
5877 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5878 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5879 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5880 false) >= 2)
5881 #endif
5883 /* EXP is some logical combination of boolean tests. See if we can
5884 merge it into some range test. Return the new tree if so. */
5886 static tree
5889 {
5905 /* If this is an OR operation, invert both sides; we will invert
5906 again at the end. */
5910 /* If both expressions are the same, if we can merge the ranges, and we
5911 can build the range test, return it or it inverted. If one of the
5912 ranges is always true or always false, consider it to be the same
5913 expression as the other. */
5921 {
5925 }
5927 /* On machines where the branch cost is expensive, if this is a
5928 short-circuited branch and the underlying object on both sides
5929 is the same, make a non-short-circuit operation. */
5932 logical_op_non_short_circuit
5935 && !flag_sanitize_coverage
5939 {
5940 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5941 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5942 which cases we can't do this. */
5950 {
5959 {
5962 WARN_STRICT_OVERFLOW_COMPARISON);
5966 }
5967 }
5968 }
5971 }
5972 \f
5973 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5974 bit value. Arrange things so the extra bits will be set to zero if and
5975 only if C is signed-extended to its full width. If MASK is nonzero,
5976 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5978 static tree
5980 {
5983 tree temp;
5988 /* We work by getting just the sign bit into the low-order bit, then
5989 into the high-order bit, then sign-extend. We then XOR that value
5990 with C. */
5994 /* We must use a signed type in order to get an arithmetic right shift.
5995 However, we must also avoid introducing accidental overflows, so that
5996 a subsequent call to integer_zerop will work. Hence we must
5997 do the type conversion here. At this point, the constant is either
5998 zero or one, and the conversion to a signed type can never overflow.
5999 We could get an overflow if this conversion is done anywhere else. */
6008 /* If necessary, convert the type back to match the type of C. */
6013 }
6014 \f
6015 /* For an expression that has the form
6016 (A && B) || ~B
6017 or
6018 (A || B) && ~B,
6019 we can drop one of the inner expressions and simplify to
6020 A || ~B
6021 or
6022 A && ~B
6023 LOC is the location of the resulting expression. OP is the inner
6024 logical operation; the left-hand side in the examples above, while CMPOP
6025 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6026 removing a condition that guards another, as in
6027 (A != NULL && A->...) || A == NULL
6028 which we must not transform. If RHS_ONLY is true, only eliminate the
6029 right-most operand of the inner logical operation. */
6031 static tree
6034 {
6052 {
6055 {
6058 }
6059 }
6061 {
6064 {
6067 }
6068 }
6083 }
6085 /* Find ways of folding logical expressions of LHS and RHS:
6086 Try to merge two comparisons to the same innermost item.
6087 Look for range tests like "ch >= '0' && ch <= '9'".
6088 Look for combinations of simple terms on machines with expensive branches
6089 and evaluate the RHS unconditionally.
6091 For example, if we have p->a == 2 && p->b == 4 and we can make an
6092 object large enough to span both A and B, we can do this with a comparison
6093 against the object ANDed with the a mask.
6095 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6096 operations to do this with one comparison.
6098 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6099 function and the one above.
6101 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6102 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6104 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6105 two operands.
6107 We return the simplified tree or 0 if no optimization is possible. */
6109 static tree
6112 {
6113 /* If this is the "or" of two comparisons, we can do something if
6114 the comparisons are NE_EXPR. If this is the "and", we can do something
6115 if the comparisons are EQ_EXPR. I.e.,
6116 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6118 WANTED_CODE is this operation code. For single bit fields, we can
6119 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6120 comparison for one-bit fields. */
6141 /* Start by getting the comparison codes. Fail if anything is volatile.
6142 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6143 it were surrounded with a NE_EXPR. */
6152 {
6156 }
6159 {
6163 }
6174 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6177 {
6180 {
6185 }
6188 {
6194 }
6195 }
6200 /* If the RHS can be evaluated unconditionally and its operands are
6201 simple, it wins to evaluate the RHS unconditionally on machines
6202 with expensive branches. In this case, this isn't a comparison
6203 that can be merged. */
6210 {
6211 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6222 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6232 }
6234 /* See if the comparisons can be merged. Then get all the parameters for
6235 each side. */
6260 /* It must be true that the inner operation on the lhs of each
6261 comparison must be the same if we are to be able to do anything.
6262 Then see if we have constants. If not, the same must be true for
6263 the rhs's. */
6272 {
6275 }
6280 else
6283 /* If either comparison code is not correct for our logical operation,
6284 fail. However, we can convert a one-bit comparison against zero into
6285 the opposite comparison against that bit being set in the field. */
6289 {
6291 {
6292 /* Make the left operand unsigned, since we are only interested
6293 in the value of one bit. Otherwise we are doing the wrong
6294 thing below. */
6297 }
6298 else
6300 }
6302 /* This is analogous to the code for l_const above. */
6304 {
6306 {
6309 }
6310 else
6312 }
6314 /* See if we can find a mode that contains both fields being compared on
6315 the left. If we can't, fail. Otherwise, update all constants and masks
6316 to be relative to a field of that size. */
6330 {
6333 }
6341 {
6348 {
6352 }
6353 }
6355 {
6362 {
6366 }
6367 }
6369 /* If the right sides are not constant, do the same for it. Also,
6370 disallow this optimization if a size, signedness or storage order
6371 mismatch occurs between the left and right sides. */
6373 {
6377 /* Make sure the two fields on the right
6378 correspond to the left without being swapped. */
6395 {
6398 }
6407 /* Make a mask that corresponds to both fields being compared.
6408 Do this for both items being compared. If the operands are the
6409 same size and the bits being compared are in the same position
6410 then we can do this by masking both and comparing the masked
6411 results. */
6418 {
6432 }
6434 /* There is still another way we can do something: If both pairs of
6435 fields being compared are adjacent, we may be able to make a wider
6436 field containing them both.
6438 Note that we still must mask the lhs/rhs expressions. Furthermore,
6439 the mask must be shifted to account for the shift done by
6440 make_bit_field_ref. */
6449 {
6450 tree type;
6466 /* Convert to the smaller type before masking out unwanted bits. */
6469 {
6471 {
6475 }
6477 {
6481 }
6482 }
6491 }
6494 }
6496 /* Handle the case of comparisons with constants. If there is something in
6497 common between the masks, those bits of the constants must be the same.
6498 If not, the condition is always false. Test for this to avoid generating
6499 incorrect code below. */
6504 {
6506 {
6509 }
6510 else
6511 {
6514 }
6515 }
6520 /* Construct the expression we will return. First get the component
6521 reference we will make. Unless the mask is all ones the width of
6522 that field, perform the mask operation. Then compare with the
6523 merged constant. */
6534 }
6535 \f
6536 /* T is an integer expression that is being multiplied, divided, or taken a
6537 modulus (CODE says which and what kind of divide or modulus) by a
6538 constant C. See if we can eliminate that operation by folding it with
6539 other operations already in T. WIDE_TYPE, if non-null, is a type that
6540 should be used for the computation if wider than our type.
6542 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6543 (X * 2) + (Y * 4). We must, however, be assured that either the original
6544 expression would not overflow or that overflow is undefined for the type
6545 in the language in question.
6547 If we return a non-null expression, it is an equivalent form of the
6548 original computation, but need not be in the original type.
6550 We set *STRICT_OVERFLOW_P to true if the return values depends on
6551 signed overflow being undefined. Otherwise we do not change
6552 *STRICT_OVERFLOW_P. */
6554 static tree
6557 {
6558 /* To avoid exponential search depth, refuse to allow recursion past
6559 three levels. Beyond that (1) it's highly unlikely that we'll find
6560 something interesting and (2) we've probably processed it before
6561 when we built the inner expression. */
6564 tree ret;
6569 depth++;
6571 depth--;
6574 }
6576 static tree
6579 {
6591 /* Don't deal with constants of zero here; they confuse the code below. */
6601 /* Note that we need not handle conditional operations here since fold
6602 already handles those cases. So just do arithmetic here. */
6604 {
6606 /* For a constant, we can always simplify if we are a multiply
6607 or (for divide and modulus) if it is a multiple of our constant. */
6611 {
6614 /* If the multiplication overflowed, we lost information on it.
6615 See PR68142 and PR69845. */
6619 }
6623 /* If op0 is an expression ... */
6629 /* ... and has wrapping overflow, and its type is smaller
6630 than ctype, then we cannot pass through as widening. */
6635 /* ... or this is a truncation (t is narrower than op0),
6636 then we cannot pass through this narrowing. */
6639 /* ... or signedness changes for division or modulus,
6640 then we cannot pass through this conversion. */
6644 /* ... or has undefined overflow while the converted to
6645 type has not, we cannot do the operation in the inner type
6646 as that would introduce undefined overflow. */
6652 /* Pass the constant down and see if we can make a simplification. If
6653 we can, replace this expression with the inner simplification for
6654 possible later conversion to our or some other type. */
6665 /* If widening the type changes it from signed to unsigned, then we
6666 must avoid building ABS_EXPR itself as unsigned. */
6668 {
6672 {
6675 }
6677 }
6678 /* If the constant is negative, we cannot simplify this. */
6681 /* FALLTHROUGH */
6683 /* For division and modulus, type can't be unsigned, as e.g.
6684 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6685 For signed types, even with wrapping overflow, this is fine. */
6694 /* If widening the type changes the signedness, then we can't perform
6695 this optimization as that changes the result. */
6699 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6705 {
6712 }
6716 /* If the second operand is constant, this is a multiplication
6717 or floor division, by a power of two, so we can treat it that
6718 way unless the multiplier or divisor overflows. Signed
6719 left-shift overflow is implementation-defined rather than
6720 undefined in C90, so do not convert signed left shift into
6721 multiplication. */
6724 /* const_binop may not detect overflow correctly,
6725 so check for it explicitly here. */
6734 ctype,
6736 t1),
6741 /* See if we can eliminate the operation on both sides. If we can, we
6742 can return a new PLUS or MINUS. If we can't, the only remaining
6743 cases where we can do anything are if the second operand is a
6744 constant. */
6751 /* If not multiplication, we can only do this if both operands
6752 are divisible by c. */
6755 {
6760 }
6762 /* If this was a subtraction, negate OP1 and set it to be an addition.
6763 This simplifies the logic below. */
6765 {
6767 /* If OP1 was not easily negatable, the constant may be OP0. */
6769 {
6772 }
6773 }
6778 /* If either OP1 or C are negative, this optimization is not safe for
6779 some of the division and remainder types while for others we need
6780 to change the code. */
6782 {
6790 }
6792 /* If it's a multiply or a division/modulus operation of a multiple
6793 of our constant, do the operation and verify it doesn't overflow. */
6797 {
6800 /* We allow the constant to overflow with wrapping semantics. */
6804 }
6805 else
6808 /* If we have an unsigned type, we cannot widen the operation since it
6809 will change the result if the original computation overflowed. */
6813 /* The last case is if we are a multiply. In that case, we can
6814 apply the distributive law to commute the multiply and addition
6815 if the multiplication of the constants doesn't overflow
6816 and overflow is defined. With undefined overflow
6817 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6818 But fold_plusminus_mult_expr would factor back any power-of-two
6819 value so do not distribute in the first place in this case. */
6827 op1);
6832 /* We have a special case here if we are doing something like
6833 (C * 8) % 4 since we know that's zero. */
6836 /* If the multiplication can overflow we cannot optimize this. */
6841 {
6844 }
6846 /* ... fall through ... */
6850 /* If we can extract our operation from the LHS, do so and return a
6851 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6852 do something only if the second operand is a constant. */
6868 /* If these are the same operation types, we can associate them
6869 assuming no overflow. */
6871 {
6886 }
6888 /* If these operations "cancel" each other, we have the main
6889 optimizations of this pass, which occur when either constant is a
6890 multiple of the other, in which case we replace this with either an
6891 operation or CODE or TCODE.
6893 If we have an unsigned type, we cannot do this since it will change
6894 the result if the original computation overflowed. */
6901 {
6904 {
6911 }
6914 {
6921 }
6922 }
6927 }
6930 }
6931 \f
6932 /* Return a node which has the indicated constant VALUE (either 0 or
6933 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6934 and is of the indicated TYPE. */
6936 tree
6938 {
6947 else
6949 }
6952 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6953 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6954 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6955 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6956 COND is the first argument to CODE; otherwise (as in the example
6957 given here), it is the second argument. TYPE is the type of the
6958 original expression. Return NULL_TREE if no simplification is
6959 possible. */
6961 static tree
6966 {
6974 /* Do not move possibly trapping operations into the conditional as this
6975 pessimizes code and causes gimplification issues when applied late. */
6983 {
6987 /* If this operand throws an expression, then it does not make
6988 sense to try to perform a logical or arithmetic operation
6989 involving it. */
6994 }
6997 {
7002 }
7003 else
7004 /* Detect the case of mixing vector and scalar types - bail out. */
7010 /* This transformation is only worthwhile if we don't have to wrap ARG
7011 in a SAVE_EXPR and the operation can be simplified without recursing
7012 on at least one of the branches once its pushed inside the COND_EXPR. */
7021 {
7025 else
7027 }
7029 {
7033 else
7035 }
7037 /* Check that we have simplified at least one of the branches. */
7042 }
7044 \f
7045 /* Subroutine of fold() that checks for the addition of +/- 0.0.
7047 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
7048 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
7049 ADDEND is the same as X.
7051 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7052 and finite. The problematic cases are when X is zero, and its mode
7053 has signed zeros. In the case of rounding towards -infinity,
7054 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7055 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7057 bool
7059 {
7063 /* Don't allow the fold with -fsignaling-nans. */
7067 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7071 /* There is no case that is safe for all rounding modes. */
7075 /* In a vector or complex, we would need to check the sign of all zeros. */
7081 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7085 /* The mode has signed zeros, and we have to honor their sign.
7086 In this situation, there is only one case we can return true for.
7087 X - 0 is the same as X with default rounding. */
7089 }
7091 /* Subroutine of match.pd that optimizes comparisons of a division by
7092 a nonzero integer constant against an integer constant, i.e.
7093 X/C1 op C2.
7095 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7096 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7098 enum tree_code
7101 {
7106 /* We have to do this the hard way to detect unsigned overflow.
7107 prod = int_const_binop (MULT_EXPR, c1, c2); */
7113 {
7117 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7120 }
7122 {
7125 {
7144 }
7145 }
7146 else
7147 {
7148 /* A negative divisor reverses the relational operators. */
7153 {
7172 }
7173 }
7186 }
7189 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7190 equality/inequality test, then return a simplified form of the test
7191 using a sign testing. Otherwise return NULL. TYPE is the desired
7192 result type. */
7194 static tree
7197 tree result_type)
7198 {
7199 /* If this is testing a single bit, we can optimize the test. */
7203 {
7204 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7205 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7209 /* This is only a win if casting to a signed type is cheap,
7210 i.e. when arg00's type is not a partial mode. */
7212 {
7215 result_type,
7218 }
7219 }
7222 }
7224 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7225 equality/inequality test, then return a simplified form of
7226 the test using shifts and logical operations. Otherwise return
7227 NULL. TYPE is the desired result type. */
7229 tree
7232 {
7233 /* If this is testing a single bit, we can optimize the test. */
7237 {
7246 /* First, see if we can fold the single bit test into a sign-bit
7247 test. */
7249 result_type);
7253 /* Otherwise we have (A & C) != 0 where C is a single bit,
7254 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7255 Similarly for (A & C) == 0. */
7257 /* If INNER is a right shift of a constant and it plus BITNUM does
7258 not overflow, adjust BITNUM and INNER. */
7264 {
7267 }
7269 /* If we are going to be able to omit the AND below, we must do our
7270 operations as unsigned. If we must use the AND, we have a choice.
7271 Normally unsigned is faster, but for some machines signed is. */
7289 /* Put the AND last so it can combine with more things. */
7292 /* Make sure to return the proper type. */
7296 }
7298 }
7300 /* Test whether it is preferable two swap two operands, ARG0 and
7301 ARG1, for example because ARG0 is an integer constant and ARG1
7302 isn't. */
7304 bool
7306 {
7320 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7321 for commutative and comparison operators. Ensuring a canonical
7322 form allows the optimizers to find additional redundancies without
7323 having to explicitly check for both orderings. */
7329 /* Put SSA_NAMEs last. */
7335 /* Put variables last. */
7342 }
7345 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7346 means A >= Y && A != MAX, but in this case we know that
7347 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7349 static tree
7351 {
7358 else
7367 {
7370 }
7372 {
7375 }
7376 else
7383 {
7384 /* Convert the pointer types into integer before taking the difference. */
7388 }
7389 else
7396 }
7398 /* Fold a sum or difference of at least one multiplication.
7399 Returns the folded tree or NULL if no simplification could be made. */
7401 static tree
7404 {
7408 /* (A * C) +- (B * C) -> (A+-B) * C.
7409 (A * C) +- A -> A * (C+-1).
7410 We are most concerned about the case where C is a constant,
7411 but other combinations show up during loop reduction. Since
7412 it is not difficult, try all four possibilities. */
7415 {
7418 }
7420 {
7423 }
7424 else
7425 {
7426 /* We cannot generate constant 1 for fract. */
7431 }
7433 {
7436 }
7438 {
7440 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7441 the purpose of this canonicalization. */
7445 {
7448 }
7449 else
7451 }
7452 else
7453 {
7454 /* We cannot generate constant 1 for fract. */
7459 }
7462 /* Prefer factoring a common non-constant. */
7472 /* No identical multiplicands; see if we can find a common
7473 power-of-two factor in non-power-of-two multiplies. This
7474 can help in multi-dimensional array access. */
7476 {
7479 HOST_WIDE_INT tmp;
7481 tree maybe_same;
7483 /* Move min of absolute values to int11. */
7485 {
7490 }
7491 else
7498 /* The remainder should not be a constant, otherwise we
7499 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7500 increased the number of multiplications necessary. */
7502 {
7510 }
7511 }
7518 /* We are neither factoring zero nor minus one. */
7526 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7527 same may be minus one and thus the multiplication may overflow. Perform
7528 the sum operation in an unsigned type. */
7533 /* If the sum evaluated to a constant that is not -INF the multiplication
7534 cannot overflow. */
7541 /* Do not resort to unsigned multiplication because
7542 we lose the no-overflow property of the expression. */
7544 }
7546 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7547 specified by EXPR into the buffer PTR of length LEN bytes.
7548 Return the number of bytes placed in the buffer, or zero
7549 upon failure. */
7551 static int
7553 {
7565 /* Dry run. */
7571 {
7573 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7574 number of bytes. */
7578 {
7585 else
7587 }
7588 else
7592 }
7594 }
7597 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7598 specified by EXPR into the buffer PTR of length LEN bytes.
7599 Return the number of bytes placed in the buffer, or zero
7600 upon failure. */
7602 static int
7604 {
7608 FIXED_VALUE_TYPE value;
7623 }
7626 /* Subroutine of native_encode_expr. Encode the REAL_CST
7627 specified by EXPR into the buffer PTR of length LEN bytes.
7628 Return the number of bytes placed in the buffer, or zero
7629 upon failure. */
7631 static int
7633 {
7639 /* There are always 32 bits in each long, no matter the size of
7640 the hosts long. We handle floating point representations with
7641 up to 192 bits. */
7650 /* Dry run. */
7659 {
7664 {
7671 else
7673 }
7674 else
7675 {
7678 {
7679 /* Reverse bytes within each long, or within the entire float
7680 if it's smaller than a long (for HFmode). */
7683 }
7684 }
7689 }
7691 }
7693 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7694 specified by EXPR into the buffer PTR of length LEN bytes.
7695 Return the number of bytes placed in the buffer, or zero
7696 upon failure. */
7698 static int
7700 {
7702 tree part;
7716 }
7719 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7720 specified by EXPR into the buffer PTR of length LEN bytes.
7721 Return the number of bytes placed in the buffer, or zero
7722 upon failure. */
7724 static int
7726 {
7737 {
7739 {
7742 }
7753 }
7755 }
7758 /* Subroutine of native_encode_expr. Encode the STRING_CST
7759 specified by EXPR into the buffer PTR of length LEN bytes.
7760 Return the number of bytes placed in the buffer, or zero
7761 upon failure. */
7763 static int
7765 {
7768 /* Wide-char strings are encoded in target byte-order so native
7769 encoding them is trivial. */
7784 {
7787 {
7790 }
7793 }
7794 else
7797 }
7800 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7801 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7802 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7803 anything, just do a dry run. If OFF is not -1 then start
7804 the encoding at byte offset OFF and encode at most LEN bytes.
7805 Return the number of bytes placed in the buffer, or zero upon failure. */
7807 int
7809 {
7810 /* We don't support starting at negative offset and -1 is special. */
7815 {
7836 }
7837 }
7840 /* Subroutine of native_interpret_expr. Interpret the contents of
7841 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7842 If the buffer cannot be interpreted, return NULL_TREE. */
7844 static tree
7846 {
7856 }
7859 /* Subroutine of native_interpret_expr. Interpret the contents of
7860 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7861 If the buffer cannot be interpreted, return NULL_TREE. */
7863 static tree
7865 {
7868 double_int result;
7869 FIXED_VALUE_TYPE fixed_value;
7879 }
7882 /* Subroutine of native_interpret_expr. Interpret the contents of
7883 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7884 If the buffer cannot be interpreted, return NULL_TREE. */
7886 static tree
7888 {
7892 /* There are always 32 bits in each long, no matter the size of
7893 the hosts long. We handle floating point representations with
7894 up to 192 bits. */
7895 REAL_VALUE_TYPE r;
7905 {
7906 /* Both OFFSET and BYTE index within a long;
7907 bitpos indexes the whole float. */
7910 {
7917 else
7919 }
7920 else
7921 {
7924 {
7925 /* Reverse bytes within each long, or within the entire float
7926 if it's smaller than a long (for HFmode). */
7929 }
7930 }
7934 }
7938 }
7941 /* Subroutine of native_interpret_expr. Interpret the contents of
7942 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7943 If the buffer cannot be interpreted, return NULL_TREE. */
7945 static tree
7947 {
7962 }
7965 /* Subroutine of native_interpret_expr. Interpret the contents of
7966 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7967 If the buffer cannot be interpreted, return NULL_TREE. */
7969 static tree
7971 {
7984 {
7989 }
7991 }
7994 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7995 the buffer PTR of length LEN as a constant of type TYPE. For
7996 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7997 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7998 return NULL_TREE. */
8000 tree
8002 {
8004 {
8026 }
8027 }
8029 /* Returns true if we can interpret the contents of a native encoding
8030 as TYPE. */
8032 static bool
8034 {
8036 {
8049 }
8050 }
8053 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
8054 TYPE at compile-time. If we're unable to perform the conversion
8055 return NULL_TREE. */
8057 static tree
8059 {
8060 /* We support up to 512-bit values (for V8DFmode). */
8064 /* Check that the host and target are sane. */
8073 }
8075 /* Build an expression for the address of T. Folds away INDIRECT_REF
8076 to avoid confusing the gimplify process. */
8078 tree
8080 {
8081 /* The size of the object is not relevant when talking about its address. */
8086 {
8091 }
8101 {
8106 }
8107 else
8111 }
8113 /* Build an expression for the address of T. */
8115 tree
8117 {
8121 }
8123 /* Fold a unary expression of code CODE and type TYPE with operand
8124 OP0. Return the folded expression if folding is successful.
8125 Otherwise, return NULL_TREE. */
8127 tree
8129 {
8130 tree tem;
8131 tree arg0;
8139 {
8142 {
8143 /* Don't use STRIP_NOPS, because signedness of argument type
8144 matters. */
8146 }
8147 else
8148 {
8149 /* Strip any conversions that don't change the mode. This
8150 is safe for every expression, except for a comparison
8151 expression because its signedness is derived from its
8152 operands.
8154 Note that this is done as an internal manipulation within
8155 the constant folder, in order to find the simplest
8156 representation of the arguments so that their form can be
8157 studied. In any cases, the appropriate type conversions
8158 should be put back in the tree that will get out of the
8159 constant folder. */
8161 }
8164 {
8167 {
8171 }
8172 }
8173 }
8180 {
8187 {
8201 /* If this was a conversion, and all we did was to move into
8202 inside the COND_EXPR, bring it back out. But leave it if
8203 it is a conversion from integer to integer and the
8204 result precision is no wider than a word since such a
8205 conversion is cheap and may be optimized away by combine,
8206 while it couldn't if it were outside the COND_EXPR. Then return
8207 so we don't get into an infinite recursion loop taking the
8208 conversion out and then back in. */
8220 && (INTEGRAL_TYPE_P
8233 }
8234 }
8237 {
8243 CASE_CONVERT:
8247 {
8248 /* If we have (type) (a CMP b) and type is an integral type, return
8249 new expression involving the new type. Canonicalize
8250 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
8251 non-integral type.
8252 Do not fold the result as that would not simplify further, also
8253 folding again results in recursions. */
8263 }
8265 /* Handle (T *)&A.B.C for A being of type T and B and C
8266 living at offset zero. This occurs frequently in
8267 C++ upcasting and then accessing the base. */
8271 {
8273 tree offset;
8274 machine_mode mode;
8276 tree base
8280 /* If the reference was to a (constant) zero offset, we can use
8281 the address of the base if it has the same base type
8282 as the result type and the pointer type is unqualified. */
8290 }
8294 /* Detect assigning a bitfield. */
8296 && DECL_BIT_FIELD
8298 {
8299 /* Don't leave an assignment inside a conversion
8300 unless assigning a bitfield. */
8302 /* First do the assignment, then return converted constant. */
8307 }
8309 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
8310 constants (if x has signed type, the sign bit cannot be set
8311 in c). This folds extension into the BIT_AND_EXPR.
8312 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
8313 very likely don't have maximal range for their precision and this
8314 transformation effectively doesn't preserve non-maximal ranges. */
8318 {
8329 <= HOST_BITS_PER_WIDE_INT
8331 {
8335 cst &= HOST_WIDE_INT_M1U
8339 && !flag_syntax_only
8342 {
8346 }
8347 }
8349 {
8354 }
8355 }
8357 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
8358 cast (T1)X will fold away. We assume that this happens when X itself
8359 is a cast. */
8363 {
8367 return fold_build_pointer_plus_loc
8369 }
8371 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
8372 of the same precision, and X is an integer type not narrower than
8373 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
8379 {
8385 }
8387 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
8388 type of X and Y (integer types only). */
8393 {
8394 /* Be careful not to introduce new overflows. */
8395 tree mult_type;
8398 else
8402 {
8409 }
8410 }
8416 {
8423 }
8434 /* Convert fabs((double)float) into (double)fabsf(float). */
8437 {
8443 targ0));
8444 }
8448 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
8467 /* Note that the operand of this must be an int
8468 and its values must be 0 or 1.
8469 ("true" is a fixed value perhaps depending on the language,
8470 but we don't handle values other than 1 correctly yet.) */
8477 /* Fold *&X to X if X is an lvalue. */
8479 {
8486 }
8492 }
8495 /* If the operation was a conversion do _not_ mark a resulting constant
8496 with TREE_OVERFLOW if the original constant was not. These conversions
8497 have implementation defined behavior and retaining the TREE_OVERFLOW
8498 flag here would confuse later passes such as VRP. */
8499 tree
8502 {
8511 }
8513 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
8514 operands OP0 and OP1. LOC is the location of the resulting expression.
8515 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
8516 Return the folded expression if folding is successful. Otherwise,
8517 return NULL_TREE. */
8518 static tree
8521 {
8522 tree tem;
8524 /* We only do these simplifications if we are optimizing. */
8528 /* Check for things like (A || B) && (A || C). We can convert this
8529 to A || (B && C). Note that either operator can be any of the four
8530 truth and/or operations and the transformation will still be
8531 valid. Also note that we only care about order for the
8532 ANDIF and ORIF operators. If B contains side effects, this
8533 might change the truth-value of A. */
8540 {
8560 /* This case if tricky because we must either have commutative
8561 operators or else A10 must not have side-effects. */
8567 a01);
8568 }
8570 /* See if we can build a range comparison. */
8576 {
8580 }
8584 {
8588 }
8590 /* Check for the possibility of merging component references. If our
8591 lhs is another similar operation, try to merge its rhs with our
8592 rhs. Then try to merge our lhs and rhs. */
8603 logical_op_non_short_circuit
8606 && !flag_sanitize_coverage
8611 {
8618 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8619 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8620 We don't want to pack more than two leafs to a non-IF AND/OR
8621 expression.
8622 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8623 equal to IF-CODE, then we don't want to add right-hand operand.
8624 If the inner right-hand side of left-hand operand has
8625 side-effects, or isn't simple, then we can't add to it,
8626 as otherwise we might destroy if-sequence. */
8629 /* Needed for sequence points to handle trappings, and
8630 side-effects. */
8632 {
8634 arg1);
8636 tem);
8637 }
8638 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8639 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8642 /* Needed for sequence points to handle trappings, and
8643 side-effects. */
8645 {
8650 }
8651 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8652 into (A OR B).
8653 For sequence point consistancy, we need to check for trapping,
8654 and side-effects. */
8658 }
8661 }
8663 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8664 by changing CODE to reduce the magnitude of constants involved in
8665 ARG0 of the comparison.
8666 Returns a canonicalized comparison tree if a simplification was
8667 possible, otherwise returns NULL_TREE.
8668 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8669 valid if signed overflow is undefined. */
8671 static tree
8675 {
8680 /* Match A +- CST code arg1. We can change this only if overflow
8681 is undefined. */
8684 /* In principle pointers also have undefined overflow behavior,
8685 but that causes problems elsewhere. */
8692 /* Identify the constant in arg0 and its sign. */
8696 /* Overflowed constants and zero will cause problems. */
8701 /* See if we can reduce the magnitude of the constant in
8702 arg0 by changing the comparison code. */
8703 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8707 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8711 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8715 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8719 else
8723 /* Now build the constant reduced in magnitude. But not if that
8724 would produce one outside of its types range. */
8740 }
8742 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8743 overflow further. Try to decrease the magnitude of constants involved
8744 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8745 and put sole constants at the second argument position.
8746 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8748 static tree
8751 {
8752 tree t;
8757 /* Try canonicalization by simplifying arg0. */
8762 {
8766 }
8768 /* Try canonicalization by simplifying arg1 using the swapped
8769 comparison. */
8777 }
8779 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8780 space. This is used to avoid issuing overflow warnings for
8781 expressions like &p->x which cannot wrap. */
8783 static bool
8785 {
8792 poly_wide_int wi_offset;
8798 else
8803 precision);
8818 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8819 array. */
8828 }
8830 /* Return a positive integer when the symbol DECL is known to have
8831 a nonzero address, zero when it's known not to (e.g., it's a weak
8832 symbol), and a negative integer when the symbol is not yet in the
8833 symbol table and so whether or not its address is zero is unknown.
8834 For function local objects always return positive integer. */
8835 static int
8837 {
8842 /* Function local objects are never NULL. */
8850 }
8852 /* Subroutine of fold_binary. This routine performs all of the
8853 transformations that are common to the equality/inequality
8854 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8855 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8856 fold_binary should call fold_binary. Fold a comparison with
8857 tree code CODE and type TYPE with operands OP0 and OP1. Return
8858 the folded comparison or NULL_TREE. */
8860 static tree
8863 {
8873 /* For comparisons of pointers we can decompose it to a compile time
8874 comparison of the base objects and the offsets into the object.
8875 This requires at least one operand being an ADDR_EXPR or a
8876 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8882 {
8885 machine_mode mode;
8889 /* Get base and offset for the access. Strip ADDR_EXPR for
8890 get_inner_reference, but put it back by stripping INDIRECT_REF
8891 off the base object if possible. indirect_baseN will be true
8892 if baseN is not an address but refers to the object itself. */
8895 {
8896 base0
8902 else
8904 }
8906 {
8910 {
8911 base0
8917 else
8919 }
8922 else
8926 {
8933 }
8934 }
8938 {
8939 base1
8945 else
8947 }
8949 {
8953 {
8954 base1
8960 else
8962 }
8965 else
8969 {
8976 }
8977 }
8979 /* If we have equivalent bases we might be able to simplify. */
8983 {
8984 /* We can fold this expression to a constant if the non-constant
8985 offset parts are equal. */
8989 && (equality_code
8990 || (indirect_base0
8993 {
8999 "occur when comparing P +- C1 with "
9001 WARN_STRICT_OVERFLOW_CONDITIONAL);
9004 {
9042 }
9043 }
9044 /* We can simplify the comparison to a comparison of the variable
9045 offset parts if the constant offset parts are equal.
9046 Be careful to use signed sizetype here because otherwise we
9047 mess with array offsets in the wrong way. This is possible
9048 because pointer arithmetic is restricted to retain within an
9049 object and overflow on pointer differences is undefined as of
9050 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
9052 && (equality_code
9053 || (indirect_base0
9056 {
9057 /* By converting to signed sizetype we cover middle-end pointer
9058 arithmetic which operates on unsigned pointer types of size
9059 type size and ARRAY_REF offsets which are properly sign or
9060 zero extended from their type in case it is narrower than
9061 sizetype. */
9064 else
9068 else
9075 "occur when comparing P +- C1 with "
9077 WARN_STRICT_OVERFLOW_COMPARISON);
9080 }
9081 }
9082 /* For equal offsets we can simplify to a comparison of the
9083 base addresses. */
9085 && (indirect_base0
9087 && (indirect_base1
9092 {
9098 }
9099 /* Comparison between an ordinary (non-weak) symbol and a null
9100 pointer can be eliminated since such symbols must have a non
9101 null address. In C, relational expressions between pointers
9102 to objects and null pointers are undefined. The results
9103 below follow the C++ rules with the additional property that
9104 every object pointer compares greater than a null pointer.
9105 */
9108 /* Avoid folding references to struct members at offset 0 to
9109 prevent tests like '&ptr->firstmember == 0' from getting
9110 eliminated. When ptr is null, although the -> expression
9111 is strictly speaking invalid, GCC retains it as a matter
9112 of QoI. See PR c/44555. */
9115 && indirect_base0
9116 /* The caller guarantees that when one of the arguments is
9117 constant (i.e., null in this case) it is second. */
9119 {
9121 {
9132 }
9133 }
9134 }
9136 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
9137 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
9138 the resulting offset is smaller in absolute value than the
9139 original one and has the same sign. */
9148 {
9153 tree cst;
9155 "occur when combining constants around "
9158 /* Put the constant on the side where it doesn't overflow and is
9159 of lower absolute value and of same sign than before. */
9166 {
9169 variable1,
9173 }
9181 {
9187 variable2);
9188 }
9189 }
9195 /* If we are comparing an expression that just has comparisons
9196 of two integer values, arithmetic expressions of those comparisons,
9197 and constants, we can simplify it. There are only three cases
9198 to check: the two values can either be equal, the first can be
9199 greater, or the second can be greater. Fold the expression for
9200 those three values. Since each value must be 0 or 1, we have
9201 eight possibilities, each of which corresponds to the constant 0
9202 or 1 or one of the six possible comparisons.
9204 This handles common cases like (a > b) == 0 but also handles
9205 expressions like ((x > y) - (y > x)) > 0, which supposedly
9206 occur in macroized code. */
9209 {
9213 /* Don't handle degenerate cases here; they should already
9214 have been handled anyway. */
9223 {
9227 /* We can't just pass T to eval_subst in case cval1 or cval2
9228 was the same as ARG1. */
9230 tree high_result
9234 arg1);
9235 tree equal_result
9239 arg1);
9240 tree low_result
9244 arg1);
9246 /* All three of these results should be 0 or 1. Confirm they are.
9247 Then use those values to select the proper code to use. */
9252 {
9253 /* Make a 3-bit mask with the high-order bit being the
9254 value for `>', the next for '=', and the low for '<'. */
9258 {
9260 /* Always false. */
9281 /* Always true. */
9283 }
9286 }
9287 }
9288 }
9291 }
9294 /* Subroutine of fold_binary. Optimize complex multiplications of the
9295 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9296 argument EXPR represents the expression "z" of type TYPE. */
9298 static tree
9300 {
9305 {
9308 }
9310 {
9313 }
9314 else
9315 {
9319 }
9328 }
9331 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
9332 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
9333 true if successful. */
9335 static bool
9337 {
9342 {
9345 }
9347 {
9353 else
9355 }
9356 else
9362 }
9364 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9365 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9366 NULL_TREE otherwise. */
9368 tree
9370 {
9391 {
9392 HOST_WIDE_INT index;
9398 }
9401 {
9407 }
9408 else
9410 }
9412 /* Try to fold a pointer difference of type TYPE two address expressions of
9413 array references AREF0 and AREF1 using location LOC. Return a
9414 simplified expression for the difference or NULL_TREE. */
9416 static tree
9420 {
9425 /* If the bases are array references as well, recurse. If the bases
9426 are pointer indirections compute the difference of the pointers.
9427 If the bases are equal, we are set. */
9430 && (base_offset
9432 use_pointer_diff)))
9435 && (base_offset
9436 = use_pointer_diff
9446 {
9452 base_offset,
9455 }
9457 }
9459 /* If the real or vector real constant CST of type TYPE has an exact
9460 inverse, return it, else return NULL. */
9462 tree
9464 {
9465 REAL_VALUE_TYPE r;
9466 tree unit_type;
9467 machine_mode mode;
9470 {
9480 {
9484 tree_vector_builder elts;
9489 {
9494 }
9497 }
9501 }
9502 }
9504 /* Mask out the tz least significant bits of X of type TYPE where
9505 tz is the number of trailing zeroes in Y. */
9506 static wide_int
9508 {
9513 }
9515 /* Return true when T is an address and is known to be nonzero.
9516 For floating point we further ensure that T is not denormal.
9517 Similar logic is present in nonzero_address in rtlanal.h.
9519 If the return value is based on the assumption that signed overflow
9520 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
9521 change *STRICT_OVERFLOW_P. */
9523 static bool
9525 {
9529 /* Doing something useful for floating point would need more work. */
9535 {
9538 strict_overflow_p);
9544 strict_overflow_p);
9552 }
9555 {
9558 strict_overflow_p);
9566 strict_overflow_p);
9581 strict_overflow_p);
9585 strict_overflow_p);
9588 {
9600 }
9604 }
9606 }
9608 /* Return true when T is an address and is known to be nonzero.
9609 Handle warnings about undefined signed overflow. */
9611 bool
9613 {
9620 "determining that expression is always "
9622 WARN_STRICT_OVERFLOW_MISC);
9624 }
9626 /* Return true if T is known not to be equal to an integer W. */
9628 bool
9630 {
9632 value_range_kind rtype;
9634 {
9643 {
9648 }
9653 /* If T has some known zero bits and W has any of those bits set,
9654 then T is known not to be equal to W. */
9662 }
9663 }
9665 /* Fold a binary expression of code CODE and type TYPE with operands
9666 OP0 and OP1. LOC is the location of the resulting expression.
9667 Return the folded expression if folding is successful. Otherwise,
9668 return NULL_TREE. */
9670 tree
9673 {
9688 /* Strip any conversions that don't change the mode. This is
9689 safe for every expression, except for a comparison expression
9690 because its signedness is derived from its operands. So, in
9691 the latter case, only strip conversions that don't change the
9692 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9693 preserved.
9695 Note that this is done as an internal manipulation within the
9696 constant folder, in order to find the simplest representation
9697 of the arguments so that their form can be studied. In any
9698 cases, the appropriate type conversions should be put back in
9699 the tree that will get out of the constant folder. */
9702 {
9705 }
9706 else
9707 {
9710 }
9712 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9713 constant but we can't do arithmetic on them. */
9715 {
9718 {
9722 }
9723 }
9725 /* If this is a commutative operation, and ARG0 is a constant, move it
9726 to ARG1 to reduce the number of tests below. */
9731 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9732 to ARG1 to reduce the number of tests below. */
9741 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9743 First check for cases where an arithmetic operation is applied to a
9744 compound, conditional, or comparison operation. Push the arithmetic
9745 operation inside the compound or conditional to see if any folding
9746 can then be done. Convert comparison to conditional for this purpose.
9747 The also optimizes non-constant cases that used to be done in
9748 expand_expr.
9750 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9751 one of the operands is a comparison and the other is a comparison, a
9752 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9753 code below would make the expression more complex. Change it to a
9754 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9755 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9768 {
9772 boolean_type_node,
9780 }
9784 {
9786 {
9791 tem);
9792 }
9794 {
9799 tem);
9800 }
9805 {
9811 }
9816 {
9822 }
9823 }
9826 {
9828 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9831 {
9837 }
9839 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9842 {
9843 tree base;
9844 poly_int64 coffset;
9853 }
9858 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9864 arg1),
9866 arg0)));
9872 {
9873 /* X + (X / CST) * -CST is X % CST. */
9878 {
9887 cst0));
9888 }
9889 }
9891 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9892 one. Make sure the type is not saturating and has the signedness of
9893 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9894 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9901 {
9905 }
9908 {
9909 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9910 (plus (plus (mult) (mult)) (foo)) so that we can
9911 take advantage of the factoring cases below. */
9920 {
9926 else
9939 parg0),
9941 marg)),
9945 return
9951 parg1)));
9952 }
9953 }
9954 else
9955 {
9956 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9957 to __complex__ ( x, y ). This is not the same for SNaNs or
9958 if signed zeros are involved. */
9962 {
9969 {
9973 {
9979 }
9981 {
9987 }
9988 }
9989 }
9991 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9992 We associate floats only if the user has specified
9993 -fassociative-math. */
9997 {
10002 {
10003 tree tree0;
10006 }
10007 }
10008 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
10009 We associate floats only if the user has specified
10010 -fassociative-math. */
10014 {
10019 {
10020 tree tree0;
10023 }
10024 }
10025 }
10027 bit_rotate:
10028 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
10029 is a rotate of A by C1 bits. */
10030 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
10031 is a rotate of A by B bits.
10032 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
10033 though in this case CODE must be | and not + or ^, otherwise
10034 it doesn't return A when B is 0. */
10035 {
10037 tree rtype;
10046 /* Only create rotates in complete modes. Other cases are not
10047 expanded properly. */
10050 {
10063 {
10068 }
10073 {
10076 code0 == LSHIFT_EXPR
10079 }
10081 {
10091 {
10095 orig_tree01);
10097 }
10098 }
10102 {
10113 {
10117 orig_tree01);
10119 }
10120 }
10121 }
10122 }
10124 associate:
10125 /* In most languages, can't associate operations on floats through
10126 parentheses. Rather than remember where the parentheses were, we
10127 don't associate floats at all, unless the user has specified
10128 -fassociative-math.
10129 And, we need to make sure type is not saturating. */
10133 {
10139 /* Split both trees into variables, constants, and literals. Then
10140 associate each group together, the constants with literals,
10141 then the result with variables. This increases the chances of
10142 literals being recombined later and of generating relocatable
10143 expressions for the sum of a constant and literal. */
10151 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10155 /* With undefined overflow prefer doing association in a type
10156 which wraps on overflow, if that is one of the operand types. */
10159 {
10167 }
10169 /* With undefined overflow we can only associate constants with one
10170 variable, and constants whose association doesn't overflow. */
10173 {
10175 {
10176 /* ??? If split_tree would handle NEGATE_EXPR we could
10177 simply reject these cases and the allowed cases would
10178 be the var0/minus_var1 ones. */
10184 {
10187 }
10194 {
10197 }
10203 /* The only case we can still associate with two variables
10204 is if they cancel out. */
10208 }
10214 }
10216 /* Only do something if we found more than two objects. Otherwise,
10217 nothing has changed and we risk infinite recursion. */
10225 {
10237 {
10241 }
10243 {
10247 }
10249 /* Preserve the MINUS_EXPR if the negative part of the literal is
10250 greater than the positive part. Otherwise, the multiplicative
10251 folding code (i.e extract_muldiv) may be fooled in case
10252 unsigned constants are subtracted, like in the following
10253 example: ((X*2 + 4) - 8U)/2. */
10255 {
10259 /* But avoid ending up with only negated parts. */
10261 {
10265 }
10266 else
10267 {
10271 }
10272 }
10274 /* Don't introduce overflows through reassociation. */
10279 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
10286 /* Eliminate minus_con0. */
10288 {
10295 else
10298 }
10300 /* Eliminate minus_var0. */
10302 {
10306 else
10309 }
10311 return
10314 }
10315 }
10321 /* Fold &a[i] - &a[j] to i-j. */
10326 {
10330 code
10334 }
10336 /* Further transformations are not for pointers. */
10340 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10343 /* If arg0 is e.g. unsigned int and type is int, then this could
10344 introduce UB, because if A is INT_MIN at runtime, the original
10345 expression can be well defined while the latter is not.
10346 See PR83269. */
10355 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10356 __complex__ ( x, -y ). This is not the same for SNaNs or if
10357 signed zeros are involved. */
10361 {
10368 {
10372 {
10374 arg1r ? arg1r
10379 }
10381 {
10385 arg1i ? arg1i
10388 }
10389 }
10390 }
10392 /* A - B -> A + (-B) if B is easily negatable. */
10396 /* Avoid this transformation if B is a positive REAL_CST. */
10404 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
10405 one. Make sure the type is not saturating and has the signedness of
10406 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10407 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10414 {
10418 }
10424 {
10425 /* Transform x * -C into -x * C if x is easily negatable. */
10440 {
10443 "occur when simplifying "
10445 WARN_STRICT_OVERFLOW_MISC);
10447 }
10449 /* Optimize z * conj(z) for integer complex numbers. */
10456 }
10457 else
10458 {
10459 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
10460 This is not the same for NaNs or if signed zeros are
10461 involved. */
10467 {
10470 return
10476 return
10481 }
10483 /* Optimize z * conj(z) for floating point complex numbers.
10484 Guarded by flag_unsafe_math_optimizations as non-finite
10485 imaginary components don't produce scalar results. */
10494 }
10498 /* Canonicalize (X & C1) | C2. */
10502 {
10507 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
10515 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
10517 {
10520 }
10522 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
10523 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
10524 mode which allows further optimizations. */
10529 {
10534 {
10537 }
10538 }
10541 {
10546 }
10547 }
10549 /* See if this can be simplified into a rotate first. If that
10550 is unsuccessful continue in the association code. */
10554 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
10562 /* See if this can be simplified into a rotate first. If that
10563 is unsuccessful continue in the association code. */
10567 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
10572 {
10573 tree tem2;
10580 }
10581 /* Fold ~X & 1 as (X & 1) == 0. */
10585 {
10586 tree tem2;
10593 }
10594 /* Fold !X & 1 as X == 0. */
10597 {
10601 }
10603 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
10604 multiple of 1 << CST. */
10606 {
10613 }
10615 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
10616 bits from CST2. */
10620 {
10622 wide_int masked
10629 {
10630 /* Avoid the transform if arg1 is a mask of some
10631 mode which allows further optimizations. */
10638 }
10639 }
10641 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10644 {
10649 return
10651 }
10656 /* Don't touch a floating-point divide by zero unless the mode
10657 of the constant can represent infinity. */
10663 /* (-A) / (-B) -> A / B */
10675 /* Fall through */
10678 /* Simplify A / (B << N) where A and B are positive and B is
10679 a power of 2, to A >> (N + log2(B)). */
10684 {
10687 {
10695 WARN_STRICT_OVERFLOW_MISC);
10701 }
10702 }
10704 /* Fall through */
10712 /* Convert -A / -B to A / B when the type is signed and overflow is
10713 undefined. */
10717 {
10720 "when distributing negation across "
10722 WARN_STRICT_OVERFLOW_MISC);
10727 }
10731 {
10734 "when distributing negation across "
10736 WARN_STRICT_OVERFLOW_MISC);
10741 }
10743 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10744 operation, EXACT_DIV_EXPR.
10746 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10747 At one time others generated faster code, it's not clear if they do
10748 after the last round to changes to the DIV code in expmed.c. */
10759 {
10763 WARN_STRICT_OVERFLOW_MISC);
10765 }
10777 {
10781 WARN_STRICT_OVERFLOW_MISC);
10783 }
10791 /* Since negative shift count is not well-defined,
10792 don't try to compute it in the compiler. */
10798 /* If we have a rotate of a bit operation with the rotate count and
10799 the second operand of the bit operation both constant,
10800 permute the two operations. */
10806 {
10814 }
10816 /* Two consecutive rotates adding up to the some integer
10817 multiple of the precision of the type can be ignored. */
10833 /* Note that the operands of this must be ints
10834 and their values must be 0 or 1.
10835 ("true" is a fixed value perhaps depending on the language.) */
10836 /* If first arg is constant zero, return it. */
10839 /* FALLTHRU */
10841 /* If either arg is constant true, drop it. */
10845 /* Preserve sequence points. */
10848 /* If second arg is constant zero, result is zero, but first arg
10849 must be evaluated. */
10852 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10853 case will be handled here. */
10857 /* !X && X is always false. */
10861 /* X && !X is always false. */
10866 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10867 means A >= Y && A != MAX, but in this case we know that
10868 A < X <= MAX. */
10872 {
10880 }
10889 /* Note that the operands of this must be ints
10890 and their values must be 0 or true.
10891 ("true" is a fixed value perhaps depending on the language.) */
10892 /* If first arg is constant true, return it. */
10895 /* FALLTHRU */
10897 /* If either arg is constant zero, drop it. */
10901 /* Preserve sequence points. */
10904 /* If second arg is constant true, result is true, but we must
10905 evaluate first arg. */
10908 /* Likewise for first arg, but note this only occurs here for
10909 TRUTH_OR_EXPR. */
10913 /* !X || X is always true. */
10917 /* X || !X is always true. */
10922 /* (X && !Y) || (!X && Y) is X ^ Y */
10925 {
10942 }
10951 /* If the second arg is constant zero, drop it. */
10954 /* If the second arg is constant true, this is a logical inversion. */
10956 {
10959 }
10960 /* Identical arguments cancel to zero. */
10964 /* !X ^ X is always true. */
10969 /* X ^ !X is always true. */
10985 /* bool_var != 1 becomes !bool_var. */
10992 /* bool_var == 0 becomes !bool_var. */
10999 /* !exp != 0 becomes !exp */
11004 /* If this is an EQ or NE comparison with zero and ARG0 is
11005 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11006 two operations, but the latter can be done in one less insn
11007 on machines that have only two-operand insns or on which a
11008 constant cannot be the first operand. */
11011 {
11016 {
11023 arg1);
11024 }
11027 {
11034 arg1);
11035 }
11036 }
11038 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11039 C1 is a valid shift constant, and C2 is a power of two, i.e.
11040 a single bit. */
11044 == INTEGER_CST
11047 {
11052 /* Check for a valid shift count. */
11054 {
11058 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
11059 can be rewritten as (X & (C2 << C1)) != 0. */
11061 {
11066 }
11067 /* Otherwise, for signed (arithmetic) shifts,
11068 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11069 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11073 /* Otherwise, of unsigned (logical) shifts,
11074 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11075 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11076 else
11080 arg000);
11081 }
11082 }
11084 /* If this is a comparison of a field, we may be able to simplify it. */
11087 /* Handle the constant case even without -O
11088 to make sure the warnings are given. */
11090 {
11094 }
11096 /* Optimize comparisons of strlen vs zero to a compare of the
11097 first character of the string vs zero. To wit,
11098 strlen(ptr) == 0 => *ptr == 0
11099 strlen(ptr) != 0 => *ptr != 0
11100 Other cases should reduce to one of these two (or a constant)
11101 due to the return value of strlen being unsigned. */
11103 {
11111 {
11112 tree ptrtype
11114 TYPE_QUAL_CONST));
11120 }
11121 }
11123 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
11124 of X. Similarly fold (X >> C) == 0 into X >= 0. */
11128 {
11133 {
11135 {
11138 }
11141 }
11142 }
11144 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
11145 (X & C) == 0 when C is a single bit. */
11150 {
11157 arg1));
11158 }
11160 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
11161 constant C is a power of two, i.e. a single bit. */
11168 {
11172 }
11174 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
11175 when is C is a power of two, i.e. a single bit. */
11182 {
11188 }
11192 {
11195 }
11197 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
11200 {
11208 {
11214 }
11216 {
11222 }
11224 {
11230 }
11232 {
11238 }
11239 }
11243 {
11250 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
11251 operand_equal_p guarantees no side-effects so we don't need
11252 to use omit_one_operand on Z. */
11256 arg10));
11260 arg11));
11264 arg10));
11268 arg11));
11270 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
11273 {
11279 }
11280 }
11282 /* Attempt to simplify equality/inequality comparisons of complex
11283 values. Only lower the comparison if the result is known or
11284 can be simplified to a single scalar comparison. */
11289 {
11294 {
11297 }
11298 else
11299 {
11302 }
11305 {
11308 }
11309 else
11310 {
11313 }
11317 {
11319 {
11324 }
11325 else
11326 {
11331 }
11332 }
11336 {
11338 {
11343 }
11344 else
11345 {
11350 }
11351 }
11352 }
11364 /* Transform comparisons of the form X +- C CMP X. */
11369 {
11374 /* (X - c) > X becomes false. */
11380 /* Likewise (X + c) < X becomes false. */
11386 /* Convert (X - c) <= X to true. */
11393 /* Convert (X + c) >= X to true. */
11399 }
11401 /* If we are comparing an ABS_EXPR with a constant, we can
11402 convert all the cases into explicit comparisons, but they may
11403 well not be faster than doing the ABS and one comparison.
11404 But ABS (X) <= C is a range comparison, which becomes a subtraction
11405 and a comparison, and is probably faster. */
11419 /* Convert ABS_EXPR<x> >= 0 to true. */
11426 {
11429 "when simplifying comparison of "
11431 WARN_STRICT_OVERFLOW_CONDITIONAL);
11434 arg0);
11435 }
11437 /* Convert ABS_EXPR<x> < 0 to false. */
11442 {
11445 "when simplifying comparison of "
11447 WARN_STRICT_OVERFLOW_CONDITIONAL);
11450 arg0);
11451 }
11453 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11454 and similarly for >= into !=. */
11464 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11465 otherwise Y might be >= # of bits in X's type and thus e.g.
11466 (unsigned char) (1 << Y) for Y 15 might be 0.
11467 If the cast is widening, then 1 << Y should have unsigned type,
11468 otherwise if Y is number of bits in the signed shift type minus 1,
11469 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11470 31 might be 0xffffffff80000000. */
11481 {
11487 }
11499 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11500 {
11512 }
11517 /* When pedantic, a compound expression can be neither an lvalue
11518 nor an integer constant expression. */
11521 /* Don't let (0, 0) be null pointer constant. */
11527 /* An ASSERT_EXPR should never be passed to fold_binary. */
11533 }
11535 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
11536 ((A & N) + B) & M -> (A + B) & M
11537 Similarly if (N & M) == 0,
11538 ((A | N) + B) & M -> (A + B) & M
11539 and for - instead of + (or unary - instead of +)
11540 and/or ^ instead of |.
11541 If B is constant and (B & M) == 0, fold into A & M.
11543 This function is a helper for match.pd patterns. Return non-NULL
11544 type in which the simplified operation should be performed only
11545 if any optimization is possible.
11547 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
11548 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
11549 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
11550 +/-. */
11551 tree
11556 {
11571 wide_int cst0;
11573 /* Now we know that arg0 is (C + D) or (C - D) or -C and
11574 arg1 (M) is == (1LL << cst) - 1.
11575 Store C into PMOP[0] and D into PMOP[1]. */
11582 {
11589 {
11592 }
11595 /* If C or D is of the form (A & N) where
11596 (N & M) == M, or of the form (A | N) or
11597 (A ^ N) where (N & M) == 0, replace it with A. */
11603 /* If C or D is a N where (N & M) == 0, it can be
11604 omitted (replaced with 0). */
11609 /* Similarly, with C - N where (-N & M) == 0. */
11617 }
11619 /* Only build anything new if we optimized one or both arguments above. */
11625 else
11627 }
11629 /* Used by contains_label_[p1]. */
11631 struct contains_label_data
11632 {
11635 };
11637 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11638 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
11639 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
11641 static tree
11643 {
11646 {
11657 {
11665 }
11674 }
11675 }
11677 /* Return whether the sub-tree ST contains a label which is accessible from
11678 outside the sub-tree. */
11680 static bool
11682 {
11686 }
11688 /* Fold a ternary expression of code CODE and type TYPE with operands
11689 OP0, OP1, and OP2. Return the folded expression if folding is
11690 successful. Otherwise, return NULL_TREE. */
11692 tree
11695 {
11696 tree tem;
11703 /* If this is a commutative operation, and OP0 is a constant, move it
11704 to OP1 to reduce the number of tests below. */
11713 /* Strip any conversions that don't change the mode. This is safe
11714 for every expression, except for a comparison expression because
11715 its signedness is derived from its operands. So, in the latter
11716 case, only strip conversions that don't change the signedness.
11718 Note that this is done as an internal manipulation within the
11719 constant folder, in order to find the simplest representation of
11720 the arguments so that their form can be studied. In any cases,
11721 the appropriate type conversions should be put back in the tree
11722 that will get out of the constant folder. */
11724 {
11727 }
11730 {
11733 }
11736 {
11739 }
11742 {
11746 {
11752 }
11757 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11758 so all simple results must be passed through pedantic_non_lvalue. */
11760 {
11763 /* Only optimize constant conditions when the selected branch
11764 has the same type as the COND_EXPR. This avoids optimizing
11765 away "c ? x : throw", where the throw has a void type.
11766 Avoid throwing away that operand which contains label. */
11773 }
11775 {
11782 {
11785 {
11793 }
11798 }
11799 }
11801 /* If we have A op B ? A : C, we may be able to convert this to a
11802 simpler expression, depending on the operation and the values
11803 of B and C. Signed zeros prevent all of these transformations,
11804 for reasons given above each one.
11806 Also try swapping the arguments and inverting the conditional. */
11810 {
11814 }
11819 {
11823 {
11827 }
11828 }
11830 /* If the second operand is simpler than the third, swap them
11831 since that produces better jump optimization results. */
11834 {
11836 /* See if this can be inverted. If it can't, possibly because
11837 it was a floating-point inequality comparison, don't do
11838 anything. */
11842 }
11844 /* Convert A ? 1 : 0 to simply A. */
11849 /* If we try to convert OP0 to our type, the
11850 call to fold will try to move the conversion inside
11851 a COND, which will recurse. In that case, the COND_EXPR
11852 is probably the best choice, so leave it alone. */
11856 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11857 over COND_EXPR in cases such as floating point comparisons. */
11866 arg0)));
11868 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11873 {
11874 /* sign_bit_p looks through both zero and sign extensions,
11875 but for this optimization only sign extensions are
11876 usable. */
11879 {
11882 {
11885 }
11887 }
11888 /* sign_bit_p only checks ARG1 bits within A's precision.
11889 If <sign bit of A> has wider type than A, bits outside
11890 of A's precision in <sign bit of A> need to be checked.
11891 If they are all 0, this optimization needs to be done
11892 in unsigned A's type, if they are all 1 in signed A's type,
11893 otherwise this can't be done. */
11899 {
11901 tree tem_type;
11914 {
11917 }
11919 {
11922 }
11923 else
11925 }
11928 return
11934 arg1)));
11935 }
11937 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11938 already handled above. */
11943 {
11953 op1);
11954 }
11956 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11957 is probably obsolete because the first operand should be a
11958 truth value (that's why we have the two cases above), but let's
11959 leave it in until we can confirm this for all front-ends. */
11967 /* operand_equal_p compares just value, not precision, so e.g.
11968 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
11969 second operand 32-bit -128, which is not a power of two (or vice
11970 versa. */
11977 /* Disable the transformations below for vectors, since
11978 fold_binary_op_with_conditional_arg may undo them immediately,
11979 yielding an infinite loop. */
11983 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11992 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11997 {
11999 /* Only perform transformation if ARG0 is easily inverted. */
12003 ? BIT_IOR_EXPR
12006 op1);
12007 }
12009 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
12014 {
12016 /* Only perform transformation if ARG0 is easily inverted. */
12022 op2);
12023 }
12025 /* Convert A ? 1 : B into A || B if A and B are truth values. */
12037 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
12038 of fold_ternary on them. */
12048 {
12059 {
12064 {
12066 {
12071 }
12077 }
12078 }
12079 }
12081 /* On constants we can use native encode/interpret to constant
12082 fold (nearly) all BIT_FIELD_REFs. */
12088 {
12091 /* Limit us to a reasonable amount of work. To relax the
12092 other limitations we need bit-shifting of the buffer
12093 and rounding up the size. */
12097 {
12099 unsigned HOST_WIDE_INT len
12104 {
12109 }
12110 }
12111 }
12116 /* Perform constant folding of BIT_INSERT_EXPR. */
12120 {
12121 /* Build a vector of integers from the tree mask. */
12122 vec_perm_builder builder;
12126 /* Create a vec_perm_indices for the integer vector. */
12131 }
12135 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
12138 {
12144 wide_int tem2
12148 }
12153 {
12155 unsigned HOST_WIDE_INT elsize
12158 {
12164 {
12170 }
12171 }
12172 }
12178 }
12180 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
12181 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
12182 constructor element index of the value returned. If the element is
12183 not found NULL_TREE is returned and *CTOR_IDX is updated to
12184 the index of the element after the ACCESS_INDEX position (which
12185 may be outside of the CTOR array). */
12187 tree
12190 {
12196 {
12199 {
12200 /* Static constructors for variably sized objects makes no sense. */
12203 /* ??? When it is obvious that the range is signed, treat it so. */
12208 {
12210 low_bound
12212 SIGNED);
12213 }
12214 else
12215 {
12218 }
12219 }
12220 }
12224 index_sgn);
12236 {
12237 /* Array constructor might explicitly set index, or specify a range,
12238 or leave index NULL meaning that it is next index after previous
12239 one. */
12241 {
12243 max_index = index
12245 else
12246 {
12249 index_sgn);
12250 max_index
12252 index_sgn);
12254 }
12255 }
12257 {
12263 }
12264 else
12267 /* Do we have match? */
12269 {
12271 {
12275 }
12276 }
12278 /* We're past the element we search for. Note during parsing
12279 the elements might not be sorted.
12280 ??? We should use a binary search and a flag on the
12281 CONSTRUCTOR as to whether elements are sorted in declaration
12282 order. */
12284 }
12288 }
12290 /* Perform constant folding and related simplification of EXPR.
12291 The related simplifications include x*1 => x, x*0 => 0, etc.,
12292 and application of the associative law.
12293 NOP_EXPR conversions may be removed freely (as long as we
12294 are careful not to change the type of the overall expression).
12295 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
12296 but we can constant-fold them if they have constant operands. */
12298 #ifdef ENABLE_FOLD_CHECKING
12299 # define fold(x) fold_1 (x)
12301 static
12302 #endif
12303 tree
12305 {
12309 tree tem;
12312 /* Return right away if a constant. */
12316 /* CALL_EXPR-like objects with variable numbers of operands are
12317 treated specially. */
12319 {
12321 {
12324 }
12326 }
12329 {
12334 {
12352 }
12353 }
12356 {
12358 {
12365 {
12370 }
12373 }
12375 /* Return a VECTOR_CST if possible. */
12377 {
12383 tree val;
12389 }
12397 }
12399 #ifdef ENABLE_FOLD_CHECKING
12400 #undef fold
12407 /* When --enable-checking=fold, compute a digest of expr before
12408 and after actual fold call to see if fold did not accidentally
12409 change original expr. */
12411 tree
12413 {
12414 tree ret;
12434 }
12436 void
12438 {
12449 }
12451 static void
12453 {
12455 }
12457 static void
12460 {
12466 recursive_label:
12476 {
12477 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12485 }
12493 {
12494 /* Allow these fields to be modified. */
12495 tree tmp;
12506 {
12509 }
12510 }
12512 {
12513 /* Allow TREE_NO_WARNING to be set. Perhaps we shouldn't allow that
12514 and change builtins.c etc. instead - see PR89543. */
12520 }
12531 {
12534 {
12550 }
12554 {
12567 }
12584 {
12590 }
12593 {
12595 {
12598 }
12600 }
12611 {
12614 }
12624 }
12625 }
12627 /* Helper function for outputting the checksum of a tree T. When
12628 debugging with gdb, you can "define mynext" to be "next" followed
12629 by "call debug_fold_checksum (op0)", then just trace down till the
12630 outputs differ. */
12632 DEBUG_FUNCTION void
12634 {
12649 }
12651 #endif
12653 /* Fold a unary tree expression with code CODE of type TYPE with an
12654 operand OP0. LOC is the location of the resulting expression.
12655 Return a folded expression if successful. Otherwise, return a tree
12656 expression with code CODE of type TYPE with an operand OP0. */
12658 tree
12661 {
12662 tree tem;
12663 #ifdef ENABLE_FOLD_CHECKING
12672 #endif
12678 #ifdef ENABLE_FOLD_CHECKING
12685 #endif
12687 }
12689 /* Fold a binary tree expression with code CODE of type TYPE with
12690 operands OP0 and OP1. LOC is the location of the resulting
12691 expression. Return a folded expression if successful. Otherwise,
12692 return a tree expression with code CODE of type TYPE with operands
12693 OP0 and OP1. */
12695 tree
12698 MEM_STAT_DECL)
12699 {
12700 tree tem;
12701 #ifdef ENABLE_FOLD_CHECKING
12718 #endif
12724 #ifdef ENABLE_FOLD_CHECKING
12739 #endif
12741 }
12743 /* Fold a ternary tree expression with code CODE of type TYPE with
12744 operands OP0, OP1, and OP2. Return a folded expression if
12745 successful. Otherwise, return a tree expression with code CODE of
12746 type TYPE with operands OP0, OP1, and OP2. */
12748 tree
12751 {
12752 tree tem;
12753 #ifdef ENABLE_FOLD_CHECKING
12777 #endif
12784 #ifdef ENABLE_FOLD_CHECKING
12807 #endif
12809 }
12811 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12812 arguments in ARGARRAY, and a null static chain.
12813 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12814 of type TYPE from the given operands as constructed by build_call_array. */
12816 tree
12819 {
12820 tree tem;
12821 #ifdef ENABLE_FOLD_CHECKING
12840 #endif
12846 #ifdef ENABLE_FOLD_CHECKING
12862 #endif
12864 }
12866 /* Perform constant folding and related simplification of initializer
12867 expression EXPR. These behave identically to "fold_buildN" but ignore
12868 potential run-time traps and exceptions that fold must preserve. */
12870 #define START_FOLD_INIT \
12871 int saved_signaling_nans = flag_signaling_nans;\
12872 int saved_trapping_math = flag_trapping_math;\
12873 int saved_rounding_math = flag_rounding_math;\
12874 int saved_trapv = flag_trapv;\
12875 int saved_folding_initializer = folding_initializer;\
12876 flag_signaling_nans = 0;\
12877 flag_trapping_math = 0;\
12878 flag_rounding_math = 0;\
12879 flag_trapv = 0;\
12880 folding_initializer = 1;
12882 #define END_FOLD_INIT \
12883 flag_signaling_nans = saved_signaling_nans;\
12884 flag_trapping_math = saved_trapping_math;\
12885 flag_rounding_math = saved_rounding_math;\
12886 flag_trapv = saved_trapv;\
12887 folding_initializer = saved_folding_initializer;
12889 tree
12892 {
12893 tree result;
12894 START_FOLD_INIT;
12898 END_FOLD_INIT;
12900 }
12902 tree
12905 {
12906 tree result;
12907 START_FOLD_INIT;
12911 END_FOLD_INIT;
12913 }
12915 tree
12918 {
12919 tree result;
12920 START_FOLD_INIT;
12924 END_FOLD_INIT;
12926 }
12928 #undef START_FOLD_INIT
12929 #undef END_FOLD_INIT
12931 /* Determine if first argument is a multiple of second argument. Return 0 if
12932 it is not, or we cannot easily determined it to be.
12934 An example of the sort of thing we care about (at this point; this routine
12935 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12936 fold cases do now) is discovering that
12938 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12940 is a multiple of
12942 SAVE_EXPR (J * 8)
12944 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12946 This code also handles discovering that
12948 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12950 is a multiple of 8 so we don't have to worry about dealing with a
12951 possible remainder.
12953 Note that we *look* inside a SAVE_EXPR only to determine how it was
12954 calculated; it is not safe for fold to do much of anything else with the
12955 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12956 at run time. For example, the latter example above *cannot* be implemented
12957 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12958 evaluation time of the original SAVE_EXPR is not necessarily the same at
12959 the time the new expression is evaluated. The only optimization of this
12960 sort that would be valid is changing
12962 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12964 divided by 8 to
12966 SAVE_EXPR (I) * SAVE_EXPR (J)
12968 (where the same SAVE_EXPR (J) is used in the original and the
12969 transformed version). */
12971 int
12973 {
12984 {
12986 /* Bitwise and provides a power of two multiple. If the mask is
12987 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12995 {
13001 {
13004 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
13006 {
13010 {
13013 }
13014 }
13016 }
13017 }
13022 /* It is impossible to prove if op0 - op1 is multiple of bottom
13023 precisely, so be conservative here checking if both op0 and op1
13024 are multiple of bottom. Note we check the second operand first
13025 since it's usually simpler. */
13030 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
13031 as op0 - 3 if the expression has unsigned type. For example,
13032 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
13042 {
13044 /* const_binop may not detect overflow correctly,
13045 so check for it explicitly here. */
13053 }
13057 /* Can't handle conversions from non-integral or wider integral type. */
13063 /* fall through */
13080 SIGNED);
13086 {
13089 /* Check for special cases to see if top is defined as multiple
13090 of bottom:
13092 top = (X & ~(bottom - 1) ; bottom is power of 2
13094 or
13096 Y = X % bottom
13097 top = X - Y. */
13116 }
13118 /* fall through */
13126 }
13127 }
13129 #define tree_expr_nonnegative_warnv_p(X, Y) \
13132 #define RECURSE(X) \
13133 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
13135 /* Return true if CODE or TYPE is known to be non-negative. */
13137 static bool
13139 {
13142 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13143 have a signed:1 type (where the value is -1 and 0). */
13146 }
13148 /* Return true if (CODE OP0) is known to be non-negative. If the return
13149 value is based on the assumption that signed overflow is undefined,
13150 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13151 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13153 bool
13156 {
13161 {
13163 /* We can't return 1 if flag_wrapv is set because
13164 ABS_EXPR<INT_MIN> = INT_MIN. */
13168 {
13171 }
13179 CASE_CONVERT:
13180 {
13185 {
13189 {
13193 }
13194 }
13196 {
13202 }
13203 }
13208 }
13210 /* We don't know sign of `t', so be conservative and return false. */
13212 }
13214 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13215 value is based on the assumption that signed overflow is undefined,
13216 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13217 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13219 bool
13223 {
13228 {
13234 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13235 both unsigned and at least 2 bits shorter than the result. */
13239 {
13244 {
13248 }
13249 }
13254 {
13255 /* x * x is always non-negative for floating point x
13256 or without overflow. */
13259 {
13264 }
13265 }
13267 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
13268 both unsigned and their total bits is shorter than the result. */
13272 {
13291 {
13301 }
13302 }
13329 }
13331 /* We don't know sign of `t', so be conservative and return false. */
13333 }
13335 /* Return true if T is known to be non-negative. If the return
13336 value is based on the assumption that signed overflow is undefined,
13337 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13338 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13340 bool
13342 {
13347 {
13361 /* Limit the depth of recursion to avoid quadratic behavior.
13362 This is expected to catch almost all occurrences in practice.
13363 If this code misses important cases that unbounded recursion
13364 would not, passes that need this information could be revised
13365 to provide it through dataflow propagation. */
13373 }
13374 }
13376 /* Return true if T is known to be non-negative. If the return
13377 value is based on the assumption that signed overflow is undefined,
13378 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13379 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13381 bool
13384 {
13386 {
13387 CASE_CFN_ACOS:
13388 CASE_CFN_ACOSH:
13389 CASE_CFN_CABS:
13390 CASE_CFN_COSH:
13391 CASE_CFN_ERFC:
13392 CASE_CFN_EXP:
13393 CASE_CFN_EXP10:
13394 CASE_CFN_EXP2:
13395 CASE_CFN_FABS:
13396 CASE_CFN_FDIM:
13397 CASE_CFN_HYPOT:
13398 CASE_CFN_POW10:
13399 CASE_CFN_FFS:
13400 CASE_CFN_PARITY:
13401 CASE_CFN_POPCOUNT:
13402 CASE_CFN_CLZ:
13403 CASE_CFN_CLRSB:
13406 /* Always true. */
13409 CASE_CFN_SQRT:
13410 CASE_CFN_SQRT_FN:
13411 /* sqrt(-0.0) is -0.0. */
13416 CASE_CFN_ASINH:
13417 CASE_CFN_ATAN:
13418 CASE_CFN_ATANH:
13419 CASE_CFN_CBRT:
13420 CASE_CFN_CEIL:
13421 CASE_CFN_CEIL_FN:
13422 CASE_CFN_ERF:
13423 CASE_CFN_EXPM1:
13424 CASE_CFN_FLOOR:
13425 CASE_CFN_FLOOR_FN:
13426 CASE_CFN_FMOD:
13427 CASE_CFN_FREXP:
13428 CASE_CFN_ICEIL:
13429 CASE_CFN_IFLOOR:
13430 CASE_CFN_IRINT:
13431 CASE_CFN_IROUND:
13432 CASE_CFN_LCEIL:
13433 CASE_CFN_LDEXP:
13434 CASE_CFN_LFLOOR:
13435 CASE_CFN_LLCEIL:
13436 CASE_CFN_LLFLOOR:
13437 CASE_CFN_LLRINT:
13438 CASE_CFN_LLROUND:
13439 CASE_CFN_LRINT:
13440 CASE_CFN_LROUND:
13441 CASE_CFN_MODF:
13442 CASE_CFN_NEARBYINT:
13443 CASE_CFN_NEARBYINT_FN:
13444 CASE_CFN_RINT:
13445 CASE_CFN_RINT_FN:
13446 CASE_CFN_ROUND:
13447 CASE_CFN_ROUND_FN:
13448 CASE_CFN_ROUNDEVEN:
13449 CASE_CFN_ROUNDEVEN_FN:
13450 CASE_CFN_SCALB:
13451 CASE_CFN_SCALBLN:
13452 CASE_CFN_SCALBN:
13453 CASE_CFN_SIGNBIT:
13454 CASE_CFN_SIGNIFICAND:
13455 CASE_CFN_SINH:
13456 CASE_CFN_TANH:
13457 CASE_CFN_TRUNC:
13458 CASE_CFN_TRUNC_FN:
13459 /* True if the 1st argument is nonnegative. */
13462 CASE_CFN_FMAX:
13463 CASE_CFN_FMAX_FN:
13464 /* True if the 1st OR 2nd arguments are nonnegative. */
13467 CASE_CFN_FMIN:
13468 CASE_CFN_FMIN_FN:
13469 /* True if the 1st AND 2nd arguments are nonnegative. */
13472 CASE_CFN_COPYSIGN:
13473 CASE_CFN_COPYSIGN_FN:
13474 /* True if the 2nd argument is nonnegative. */
13477 CASE_CFN_POWI:
13478 /* True if the 1st argument is nonnegative or the second
13479 argument is an even integer. */
13485 CASE_CFN_POW:
13486 /* True if the 1st argument is nonnegative or the second
13487 argument is an even integer valued real. */
13489 {
13490 REAL_VALUE_TYPE c;
13491 HOST_WIDE_INT n;
13496 {
13497 REAL_VALUE_TYPE cint;
13501 }
13502 }
13507 }
13509 }
13511 /* Return true if T is known to be non-negative. If the return
13512 value is based on the assumption that signed overflow is undefined,
13513 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13514 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13516 static bool
13518 {
13524 {
13526 {
13530 /* If the initializer is non-void, then it's a normal expression
13531 that will be assigned to the slot. */
13535 /* Otherwise, the initializer sets the slot in some way. One common
13536 way is an assignment statement at the end of the initializer. */
13538 {
13546 else
13548 }
13554 }
13557 {
13563 arg0,
13564 arg1,
13566 }
13579 }
13580 }
13582 #undef RECURSE
13583 #undef tree_expr_nonnegative_warnv_p
13585 /* Return true if T is known to be non-negative. If the return
13586 value is based on the assumption that signed overflow is undefined,
13587 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13588 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13590 bool
13592 {
13599 {
13621 }
13624 {
13650 }
13651 }
13653 /* Return true if `t' is known to be non-negative. Handle warnings
13654 about undefined signed overflow. */
13656 bool
13658 {
13665 "determining that expression is always "
13667 WARN_STRICT_OVERFLOW_MISC);
13669 }
13672 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13673 For floating point we further ensure that T is not denormal.
13674 Similar logic is present in nonzero_address in rtlanal.h.
13676 If the return value is based on the assumption that signed overflow
13677 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13678 change *STRICT_OVERFLOW_P. */
13680 bool
13683 {
13685 {
13688 strict_overflow_p);
13691 {
13697 strict_overflow_p));
13698 }
13703 strict_overflow_p);
13707 }
13710 }
13712 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13713 For floating point we further ensure that T is not denormal.
13714 Similar logic is present in nonzero_address in rtlanal.h.
13716 If the return value is based on the assumption that signed overflow
13717 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13718 change *STRICT_OVERFLOW_P. */
13720 bool
13722 tree type,
13723 tree op0,
13725 {
13728 {
13732 {
13733 /* With the presence of negative values it is hard
13734 to say something. */
13741 /* One of operands must be positive and the other non-negative. */
13742 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13743 overflows, on a twos-complement machine the sum of two
13744 nonnegative numbers can never be zero. */
13746 strict_overflow_p)
13748 strict_overflow_p));
13749 }
13754 {
13756 strict_overflow_p)
13758 strict_overflow_p))
13759 {
13762 }
13763 }
13772 {
13775 }
13782 {
13786 /* When both operands are nonzero, then MAX must be too. */
13788 strict_overflow_p))
13791 /* MAX where operand 0 is positive is positive. */
13793 strict_overflow_p);
13794 }
13795 /* MAX where operand 1 is positive is positive. */
13800 {
13804 }
13809 strict_overflow_p)
13811 strict_overflow_p));
13815 }
13818 }
13820 /* Return true when T is an address and is known to be nonzero.
13821 For floating point we further ensure that T is not denormal.
13822 Similar logic is present in nonzero_address in rtlanal.h.
13824 If the return value is based on the assumption that signed overflow
13825 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13826 change *STRICT_OVERFLOW_P. */
13828 bool
13830 {
13833 {
13838 {
13850 /* For objects in symbol table check if we know they are non-zero.
13851 Don't do anything for variables and functions before symtab is built;
13852 it is quite possible that they will be declared weak later. */
13857 /* Constants are never weak. */
13862 }
13870 {
13874 }
13884 }
13886 }
13888 #define integer_valued_real_p(X) \
13891 #define RECURSE(X) \
13892 ((integer_valued_real_p) (X, depth + 1))
13894 /* Return true if the floating point result of (CODE OP0) has an
13895 integer value. We also allow +Inf, -Inf and NaN to be considered
13896 integer values. Return false for signaling NaN.
13898 DEPTH is the current nesting depth of the query. */
13900 bool
13902 {
13904 {
13911 CASE_CONVERT:
13912 {
13919 }
13923 }
13925 }
13927 /* Return true if the floating point result of (CODE OP0 OP1) has an
13928 integer value. We also allow +Inf, -Inf and NaN to be considered
13929 integer values. Return false for signaling NaN.
13931 DEPTH is the current nesting depth of the query. */
13933 bool
13935 {
13937 {
13947 }
13949 }
13951 /* Return true if the floating point result of calling FNDECL with arguments
13952 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13953 considered integer values. Return false for signaling NaN. If FNDECL
13954 takes fewer than 2 arguments, the remaining ARGn are null.
13956 DEPTH is the current nesting depth of the query. */
13958 bool
13960 {
13962 {
13963 CASE_CFN_CEIL:
13964 CASE_CFN_CEIL_FN:
13965 CASE_CFN_FLOOR:
13966 CASE_CFN_FLOOR_FN:
13967 CASE_CFN_NEARBYINT:
13968 CASE_CFN_NEARBYINT_FN:
13969 CASE_CFN_RINT:
13970 CASE_CFN_RINT_FN:
13971 CASE_CFN_ROUND:
13972 CASE_CFN_ROUND_FN:
13973 CASE_CFN_ROUNDEVEN:
13974 CASE_CFN_ROUNDEVEN_FN:
13975 CASE_CFN_TRUNC:
13976 CASE_CFN_TRUNC_FN:
13979 CASE_CFN_FMIN:
13980 CASE_CFN_FMIN_FN:
13981 CASE_CFN_FMAX:
13982 CASE_CFN_FMAX_FN:
13987 }
13989 }
13991 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13992 has an integer value. We also allow +Inf, -Inf and NaN to be
13993 considered integer values. Return false for signaling NaN.
13995 DEPTH is the current nesting depth of the query. */
13997 bool
13999 {
14001 {
14009 /* Limit the depth of recursion to avoid quadratic behavior.
14010 This is expected to catch almost all occurrences in practice.
14011 If this code misses important cases that unbounded recursion
14012 would not, passes that need this information could be revised
14013 to provide it through dataflow propagation. */
14017 depth));
14021 }
14023 }
14025 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
14026 has an integer value. We also allow +Inf, -Inf and NaN to be
14027 considered integer values. Return false for signaling NaN.
14029 DEPTH is the current nesting depth of the query. */
14031 static bool
14033 {
14035 {
14046 }
14048 }
14050 #undef RECURSE
14051 #undef integer_valued_real_p
14053 /* Return true if the floating point expression T has an integer value.
14054 We also allow +Inf, -Inf and NaN to be considered integer values.
14055 Return false for signaling NaN.
14057 DEPTH is the current nesting depth of the query. */
14059 bool
14061 {
14069 {
14085 }
14088 {
14094 {
14103 }
14107 }
14108 }
14110 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14111 attempt to fold the expression to a constant without modifying TYPE,
14112 OP0 or OP1.
14114 If the expression could be simplified to a constant, then return
14115 the constant. If the expression would not be simplified to a
14116 constant, then return NULL_TREE. */
14118 tree
14120 {
14123 }
14125 /* Given the components of a unary expression CODE, TYPE and OP0,
14126 attempt to fold the expression to a constant without modifying
14127 TYPE or OP0.
14129 If the expression could be simplified to a constant, then return
14130 the constant. If the expression would not be simplified to a
14131 constant, then return NULL_TREE. */
14133 tree
14135 {
14138 }
14140 /* If EXP represents referencing an element in a constant string
14141 (either via pointer arithmetic or array indexing), return the
14142 tree representing the value accessed, otherwise return NULL. */
14144 tree
14146 {
14150 {
14152 tree index;
14153 tree string;
14158 else
14159 {
14163 /* Optimize the special-case of a zero lower bound.
14165 We convert the low_bound to sizetype to avoid some problems
14166 with constant folding. (E.g. suppose the lower bound is 1,
14167 and its mode is QI. Without the conversion,l (ARRAY
14168 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14169 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
14175 }
14177 scalar_int_mode char_mode;
14189 }
14191 }
14193 /* Folds a read from vector element at IDX of vector ARG. */
14195 tree
14197 {
14202 {
14206 {
14210 }
14211 }
14213 }
14215 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14216 an integer constant, real, or fixed-point constant.
14218 TYPE is the type of the result. */
14220 static tree
14222 {
14226 {
14232 {
14233 FIXED_VALUE_TYPE f;
14238 /* Propagate overflow flags. */
14242 }
14246 {
14253 }
14256 }
14259 }
14261 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14262 an integer constant or real constant.
14264 TYPE is the type of the result. */
14266 tree
14268 {
14272 {
14274 {
14275 /* If the value is unsigned or non-negative, then the absolute value
14276 is the same as the ordinary value. */
14280 ;
14282 /* If the value is negative, then the absolute value is
14283 its negation. */
14284 else
14287 /* Force to the destination type, set TREE_OVERFLOW for signed
14288 TYPE only. */
14290 }
14296 else
14302 }
14305 }
14307 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14308 constant. TYPE is the type of the result. */
14310 static tree
14312 {
14316 }
14318 /* Given CODE, a relational operator, the target type, TYPE and two
14319 constant operands OP0 and OP1, return the result of the
14320 relational operation. If the result is not a compile time
14321 constant, then return NULL_TREE. */
14323 static tree
14325 {
14328 /* From here on, the only cases we handle are when the result is
14329 known to be a constant. */
14332 {
14336 /* Handle the cases where either operand is a NaN. */
14338 {
14340 {
14368 }
14371 }
14374 }
14377 {
14381 }
14383 /* Handle equality/inequality of complex constants. */
14385 {
14396 else
14398 }
14401 {
14403 {
14404 /* Have vector comparison with scalar boolean result. */
14412 {
14420 }
14422 }
14423 tree_vector_builder elts;
14428 {
14441 }
14444 }
14446 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14448 To compute GT, swap the arguments and do LT.
14449 To compute GE, do LT and invert the result.
14450 To compute LE, swap the arguments, do LT and invert the result.
14451 To compute NE, do EQ and invert the result.
14453 Therefore, the code below must handle only EQ and LT. */
14456 {
14459 }
14461 /* Note that it is safe to invert for real values here because we
14462 have already handled the one case that it matters. */
14466 {
14469 }
14471 /* Compute a result for LT or EQ if args permit;
14472 Otherwise return T. */
14474 {
14477 else
14479 }
14480 else
14486 }
14488 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
14489 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
14490 itself. */
14492 tree
14494 {
14495 /* If the expression does not have side effects then we don't have to wrap
14496 it with a cleanup point expression. */
14500 /* If the expression is a return, check to see if the expression inside the
14501 return has no side effects or the right hand side of the modify expression
14502 inside the return. If either don't have side effects set we don't need to
14503 wrap the expression in a cleanup point expression. Note we don't check the
14504 left hand side of the modify because it should always be a return decl. */
14506 {
14513 }
14516 }
14518 /* Given a pointer value OP0 and a type TYPE, return a simplified version
14519 of an indirection through OP0, or NULL_TREE if no simplification is
14520 possible. */
14522 tree
14524 {
14526 tree subtype;
14527 poly_uint64 const_op01;
14536 {
14540 /* *&CONST_DECL -> to the value of the const decl. */
14543 /* *&p => p; make sure to handle *&"str"[cst] here. */
14545 {
14549 else
14551 }
14552 /* *(foo *)&fooarray => fooarray[0] */
14555 && (!in_gimple_form
14557 {
14567 }
14568 /* *(foo *)&complexfoo => __real__ complexfoo */
14572 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14575 {
14579 index);
14580 }
14581 }
14585 {
14591 {
14592 tree op00type;
14596 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14599 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
14600 but we want to treat offsets with MSB set as negative.
14601 For the code below negative offsets are invalid and
14602 TYPE_SIZE of the element is something unsigned, so
14603 check whether op01 fits into poly_int64, which implies
14604 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
14605 then just use poly_uint64 because we want to treat the
14606 value as unsigned. */
14608 {
14610 poly_uint64 max_offset
14614 {
14619 }
14620 }
14621 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14624 {
14626 const_op01))
14628 }
14629 /* ((foo *)&fooarray)[1] => fooarray[1] */
14632 {
14641 {
14646 }
14647 }
14648 }
14649 }
14651 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14654 && (!in_gimple_form
14656 {
14657 tree type_domain;
14667 NULL_TREE);
14668 }
14671 }
14673 /* Builds an expression for an indirection through T, simplifying some
14674 cases. */
14676 tree
14678 {
14686 }
14688 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14690 tree
14692 {
14697 else
14699 }
14701 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14702 whose result is ignored. The type of the returned tree need not be
14703 the same as the original expression. */
14705 tree
14707 {
14713 {
14724 else
14730 {
14746 }
14751 }
14752 }
14754 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14756 tree
14758 {
14764 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14765 have to do anything. Only do this when we are not given a const,
14766 because in that case, this check is more expensive than just
14767 doing it. */
14769 {
14774 }
14776 /* If divisor is a power of two, simplify this to bit manipulation. */
14778 {
14780 {
14794 }
14795 else
14796 {
14797 tree t;
14803 }
14804 }
14805 else
14806 {
14811 }
14814 }
14816 /* Likewise, but round down. */
14818 tree
14820 {
14827 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14828 have to do anything. Only do this when we are not given a const,
14829 because in that case, this check is more expensive than just
14830 doing it. */
14832 {
14837 }
14839 /* If divisor is a power of two, simplify this to bit manipulation. */
14841 {
14842 tree t;
14846 }
14847 else
14848 {
14853 }
14856 }
14858 /* Returns the pointer to the base of the object addressed by EXP and
14859 extracts the information about the offset of the access, storing it
14860 to PBITPOS and POFFSET. */
14862 static tree
14865 {
14866 tree core;
14867 machine_mode mode;
14869 poly_int64 bitsize;
14873 {
14878 }
14880 {
14886 {
14887 poly_offset_int tem
14893 }
14894 }
14895 else
14896 {
14900 }
14903 }
14905 /* Returns true if addresses of E1 and E2 differ by a constant, false
14906 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14908 bool
14910 {
14925 {
14935 }
14937 {
14938 /* If only one of the offsets is non-constant, the difference cannot
14939 be a constant. */
14941 }
14942 else
14947 }
14949 /* Return OFF converted to a pointer offset type suitable as offset for
14950 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14951 tree
14953 {
14955 }
14957 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14958 tree
14960 {
14963 }
14965 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14966 tree
14968 {
14971 }
14973 /* Return a pointer P to a NUL-terminated string representing the sequence
14974 of constant characters referred to by SRC (or a subsequence of such
14975 characters within it if SRC is a reference to a string plus some
14976 constant offset). If STRLEN is non-null, store the number of bytes
14977 in the string constant including the terminating NUL char. *STRLEN is
14978 typically strlen(P) + 1 in the absence of embedded NUL characters. */
14982 {
14983 tree offset_node;
14984 tree mem_size;
14995 {
14998 else
15000 }
15005 /* STRING_LENGTH is the size of the string literal, including any
15006 embedded NULs. STRING_SIZE is the size of the array the string
15007 literal is stored in. */
15011 /* Ideally this would turn into a gcc_checking_assert over time. */
15017 /* Ideally this would turn into a gcc_checking_assert over time. */
15026 {
15027 /* Compute and store the length of the substring at OFFSET.
15028 All offsets past the initial length refer to null strings. */
15031 else
15033 }
15034 else
15035 {
15037 /* Support only properly NUL-terminated single byte strings. */
15042 }
15045 }
15047 /* Given a tree T, compute which bits in T may be nonzero. */
15049 wide_int
15051 {
15053 {
15071 CASE_CONVERT:
15077 {
15082 }
15086 {
15094 }
15098 {
15106 }
15110 }
15113 }
15115 #if CHECKING_P
15119 /* Helper functions for writing tests of folding trees. */
15121 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
15123 static void
15125 tree constant)
15126 {
15128 }
15130 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
15131 wrapping WRAPPED_EXPR. */
15133 static void
15135 tree wrapped_expr)
15136 {
15141 }
15143 /* Verify that various arithmetic binary operations are folded
15144 correctly. */
15146 static void
15148 {
15154 /* Addition. */
15155 /* 1 <-- (0 + 1) */
15157 one);
15159 one);
15161 /* (nonlvalue)x <-- (x + 0) */
15163 x);
15165 /* Subtraction. */
15166 /* 0 <-- (x - x) */
15168 zero);
15170 x);
15172 /* Multiplication. */
15173 /* 0 <-- (x * 0) */
15175 zero);
15177 /* (nonlvalue)x <-- (x * 1) */
15179 x);
15180 }
15182 /* Verify that various binary operations on vectors are folded
15183 correctly. */
15185 static void
15187 {
15194 /* Verify equality tests that return a scalar boolean result. */
15207 }
15209 /* Verify folding of VEC_DUPLICATE_EXPRs. */
15211 static void
15213 {
15216 /* This will be 1 if VEC_MODE isn't a vector mode. */
15223 }
15225 /* Run all of the selftests within this file. */
15227 void
15229 {
15233 }