| blob | ddf18f27cb7e0d7f8335908fff0b9ba5e84a68b3 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2020 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 {
2389 }
2390 }
2392 /* Convert expression ARG to type TYPE. Used by the middle-end for
2393 simple conversions in preference to calling the front-end's convert. */
2395 tree
2397 {
2399 tree tem;
2410 {
2413 /* Handle conversions between pointers to different address spaces. */
2418 /* fall through */
2423 {
2427 }
2441 {
2445 }
2447 {
2451 }
2453 {
2457 }
2460 {
2478 }
2483 {
2487 }
2490 {
2504 }
2508 {
2517 integer_zero_node));
2519 {
2523 {
2529 }
2537 }
2541 }
2559 }
2560 fold_convert_exit:
2563 }
2564 \f
2565 /* Return false if expr can be assumed not to be an lvalue, true
2566 otherwise. */
2568 static bool
2570 {
2571 /* We only need to wrap lvalue tree codes. */
2573 {
2605 /* Assume the worst for front-end tree codes. */
2609 }
2612 }
2614 /* Return an expr equal to X but certainly not valid as an lvalue. */
2616 tree
2618 {
2619 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2620 us. */
2627 }
2629 /* When pedantic, return an expr equal to X but certainly not valid as a
2630 pedantic lvalue. Otherwise, return X. */
2632 static tree
2634 {
2636 }
2637 \f
2638 /* Given a tree comparison code, return the code that is the logical inverse.
2639 It is generally not safe to do this for floating-point comparisons, except
2640 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2641 ERROR_MARK in this case. */
2643 enum tree_code
2645 {
2651 {
2682 }
2683 }
2685 /* Similar, but return the comparison that results if the operands are
2686 swapped. This is safe for floating-point. */
2688 enum tree_code
2690 {
2692 {
2718 }
2719 }
2722 /* Convert a comparison tree code from an enum tree_code representation
2723 into a compcode bit-based encoding. This function is the inverse of
2724 compcode_to_comparison. */
2726 static enum comparison_code
2728 {
2730 {
2761 }
2762 }
2764 /* Convert a compcode bit-based encoding of a comparison operator back
2765 to GCC's enum tree_code representation. This function is the
2766 inverse of comparison_to_compcode. */
2768 static enum tree_code
2770 {
2772 {
2803 }
2804 }
2806 /* Return true if COND1 tests the opposite condition of COND2. */
2808 bool
2810 {
2813 && (invert_tree_comparison
2820 }
2822 /* Return a tree for the comparison which is the combination of
2823 doing the AND or OR (depending on CODE) of the two operations LCODE
2824 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2825 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2826 if this makes the transformation invalid. */
2828 tree
2833 {
2840 {
2851 }
2854 {
2855 /* Eliminate unordered comparisons, as well as LTGT and ORD
2856 which are not used unless the mode has NaNs. */
2862 }
2864 {
2865 /* Check that the original operation and the optimized ones will trap
2866 under the same condition. */
2877 /* In a short-circuited boolean expression the LHS might be
2878 such that the RHS, if evaluated, will never trap. For
2879 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2880 if neither x nor y is NaN. (This is a mixed blessing: for
2881 example, the expression above will never trap, hence
2882 optimizing it to x < y would be invalid). */
2887 /* If the comparison was short-circuited, and only the RHS
2888 trapped, we may now generate a spurious trap. */
2893 /* If we changed the conditions that cause a trap, we lose. */
2896 }
2902 else
2903 {
2908 }
2909 }
2910 \f
2911 /* Return nonzero if two operands (typically of the same tree node)
2912 are necessarily equal. FLAGS modifies behavior as follows:
2914 If OEP_ONLY_CONST is set, only return nonzero for constants.
2915 This function tests whether the operands are indistinguishable;
2916 it does not test whether they are equal using C's == operation.
2917 The distinction is important for IEEE floating point, because
2918 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2919 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2921 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2922 even though it may hold multiple values during a function.
2923 This is because a GCC tree node guarantees that nothing else is
2924 executed between the evaluation of its "operands" (which may often
2925 be evaluated in arbitrary order). Hence if the operands themselves
2926 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2927 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2928 unset means assuming isochronic (or instantaneous) tree equivalence.
2929 Unless comparing arbitrary expression trees, such as from different
2930 statements, this flag can usually be left unset.
2932 If OEP_PURE_SAME is set, then pure functions with identical arguments
2933 are considered the same. It is used when the caller has other ways
2934 to ensure that global memory is unchanged in between.
2936 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2937 not values of expressions.
2939 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2940 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2942 If OEP_BITWISE is set, then require the values to be bitwise identical
2943 rather than simply numerically equal. Do not take advantage of things
2944 like math-related flags or undefined behavior; only return true for
2945 values that are provably bitwise identical in all circumstances.
2947 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2948 any operand with side effect. This is unnecesarily conservative in the
2949 case we know that arg0 and arg1 are in disjoint code paths (such as in
2950 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2951 addresses with TREE_CONSTANT flag set so we know that &var == &var
2952 even if var is volatile. */
2954 bool
2957 {
2965 /* If either is ERROR_MARK, they aren't equal. */
2971 /* Similar, if either does not have a type (like a template id),
2972 they aren't equal. */
2976 /* Bitwise identity makes no sense if the values have different layouts. */
2981 /* We cannot consider pointers to different address space equal. */
2988 /* Check equality of integer constants before bailing out due to
2989 precision differences. */
2991 {
2992 /* Address of INTEGER_CST is not defined; check that we did not forget
2993 to drop the OEP_ADDRESS_OF flags. */
2996 }
2999 {
3000 /* If both types don't have the same signedness, then we can't consider
3001 them equal. We must check this before the STRIP_NOPS calls
3002 because they may change the signedness of the arguments. As pointers
3003 strictly don't have a signedness, require either two pointers or
3004 two non-pointers as well. */
3010 /* If both types don't have the same precision, then it is not safe
3011 to strip NOPs. */
3018 }
3019 #if 0
3020 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3021 sanity check once the issue is solved. */
3022 else
3023 /* Addresses of conversions and SSA_NAMEs (and many other things)
3024 are not defined. Check that we did not forget to drop the
3025 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3028 #endif
3030 /* In case both args are comparisons but with different comparison
3031 code, try to swap the comparison operands of one arg to produce
3032 a match and compare that variant. */
3036 {
3044 }
3047 {
3048 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3050 ;
3052 {
3053 /* If we are interested in comparing addresses ignore
3054 MEM_REF wrappings of the base that can appear just for
3055 TBAA reasons. */
3069 }
3070 else
3072 }
3074 /* When not checking adddresses, this is needed for conversions and for
3075 COMPONENT_REF. Might as well play it safe and always test this. */
3082 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3083 We don't care about side effects in that case because the SAVE_EXPR
3084 takes care of that for us. In all other cases, two expressions are
3085 equal if they have no side effects. If we have two identical
3086 expressions with side effects that should be treated the same due
3087 to the only side effects being identical SAVE_EXPR's, that will
3088 be detected in the recursive calls below.
3089 If we are taking an invariant address of two identical objects
3090 they are necessarily equal as well. */
3097 /* Next handle constant cases, those for which we can return 1 even
3098 if ONLY_CONST is set. */
3101 {
3114 {
3115 /* If we do not distinguish between signed and unsigned zero,
3116 consider them equal. */
3119 }
3123 {
3138 }
3142 flags)
3144 flags));
3155 flags | OEP_ADDRESS_OF
3158 /* In GIMPLE empty constructors are allowed in initializers of
3159 aggregates. */
3163 }
3165 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3166 two instances of undefined behavior will give identical results. */
3170 /* Define macros to test an operand from arg0 and arg1 for equality and a
3171 variant that allows null and views null as being different from any
3172 non-null value. In the latter case, if either is null, the both
3173 must be; otherwise, do the normal comparison. */
3174 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3175 TREE_OPERAND (arg1, N), flags)
3177 #define OP_SAME_WITH_NULL(N) \
3178 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3179 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3182 {
3184 /* Two conversions are equal only if signedness and modes match. */
3186 {
3187 CASE_CONVERT:
3195 }
3205 /* For commutative ops, allow the other order. */
3213 /* If either of the pointer (or reference) expressions we are
3214 dereferencing contain a side effect, these cannot be equal,
3215 but their addresses can be. */
3222 {
3225 {
3229 /* Verify that the access types are compatible. */
3233 }
3238 /* Require the same offset. */
3244 /* Fallthru. */
3252 {
3253 /* Require equal access sizes */
3259 flags)))
3261 /* Verify that access happens in similar types. */
3264 /* Verify that accesses are TBAA compatible. */
3273 /* Verify that alignment is compatible. */
3277 }
3280 /* TARGET_MEM_REF require equal extra operands. */
3291 /* Compare the array index by value if it is constant first as we
3292 may have different types but same value here. */
3298 /* Compare low bound and element size as with OEP_ADDRESS_OF
3299 we have to account for the offset of the ref. */
3304 array_ref_low_bound
3308 array_ref_element_size
3310 flags))));
3313 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3314 may be NULL when we're called to compare MEM_EXPRs. */
3317 /* Most of time we only need to compare FIELD_DECLs for equality.
3318 However when determining address look into actual offsets.
3319 These may match for unions and unshared record types. */
3322 {
3324 {
3335 flags))
3337 }
3338 else
3340 }
3349 /* Virtual table call. */
3351 {
3365 }
3369 }
3373 {
3375 /* Be sure we pass right ADDRESS_OF flag. */
3392 /* The multiplcation operands are commutative. */
3393 /* FALLTHRU */
3401 /* Otherwise take into account this is a commutative operation. */
3414 /* BIT_INSERT_EXPR has an implict operand as the type precision
3415 of op1. Need to check to make sure they are the same. */
3421 /* FALLTHRU */
3447 }
3451 {
3455 /* If not both CALL_EXPRs are either internal or normal function
3456 functions, then they are not equal. */
3459 {
3460 /* If the CALL_EXPRs call different internal functions, then they
3461 are not equal. */
3464 }
3465 else
3466 {
3467 /* If the CALL_EXPRs call different functions, then they are not
3468 equal. */
3470 flags))
3472 }
3474 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3475 {
3479 else
3483 }
3485 /* Now see if all the arguments are the same. */
3486 {
3497 /* If we get here and both argument lists are exhausted
3498 then the CALL_EXPRs are equal. */
3500 }
3503 }
3506 /* Consider __builtin_sqrt equal to sqrt. */
3515 {
3519 /* In GIMPLE constructors are used only to build vectors from
3520 elements. Individual elements in the constructor must be
3521 indexed in increasing order and form an initial sequence.
3523 We make no effort to compare constructors in generic.
3524 (see sem_variable::equals in ipa-icf which can do so for
3525 constants). */
3530 /* Be sure that vectors constructed have the same representation.
3531 We only tested element precision and modes to match.
3532 Vectors may be BLKmode and thus also check that the number of
3533 parts match. */
3546 {
3551 /* In GIMPLE the indexes can be either NULL or matching i.
3552 Double check this so we won't get false
3553 positives for GENERIC. */
3561 }
3563 }
3566 {
3567 /* Compare the STATEMENT_LISTs. */
3573 {
3574 /* The lists don't have the same number of statements. */
3580 flags & (OEP_LEXICOGRAPHIC
3583 }
3584 }
3589 {
3600 }
3604 }
3606 #undef OP_SAME
3607 #undef OP_SAME_WITH_NULL
3608 }
3610 /* Generate a hash value for an expression. This can be used iteratively
3611 by passing a previous result as the HSTATE argument. */
3613 void
3616 {
3622 {
3625 }
3635 {
3636 /* Alas, constants aren't shared, so we can't rely on pointer
3637 identity. */
3647 {
3651 else
3655 }
3657 {
3661 }
3671 {
3678 }
3680 /* We can just compare by pointer. */
3684 /* The node itself doesn't matter. */
3688 /* Ignore. */
3691 /* A list of expressions, for a CALL_EXPR or as the elements of a
3692 VECTOR_CST. */
3697 {
3703 {
3704 /* In GIMPLE the indexes can be either NULL or matching i. */
3709 }
3711 }
3713 {
3714 tree_stmt_iterator i;
3719 }
3728 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3729 Otherwise nodes that compare equal according to operand_equal_p might
3730 get different hash codes. However, don't do this for machine specific
3731 or front end builtins, since the function code is overloaded in those
3732 cases. */
3735 {
3738 }
3739 /* FALL THROUGH */
3742 {
3746 }
3750 {
3751 /* DECL's have a unique ID */
3753 }
3755 {
3756 /* For comparisons that can be swapped, use the lower
3757 tree code. */
3764 }
3766 {
3767 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3768 operand_equal_p. */
3772 /* Don't hash the type, that can lead to having nodes which
3773 compare equal according to operand_equal_p, but which
3774 have different hash codes. Make sure to include signedness
3775 in the hash computation. */
3778 }
3779 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3787 /* Don't ICE on FE specific trees, or their arguments etc.
3788 during operand_equal_p hash verification. */
3791 else
3792 {
3798 {
3814 {
3819 else
3820 {
3826 }
3828 }
3842 {
3843 /* The multiplication operands are commutative. */
3850 }
3858 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3859 Usually different TARGET_EXPRs just should use
3860 different temporaries in their slots. */
3864 /* Virtual table call. */
3872 }
3874 /* Don't hash the type, that can lead to having nodes which
3875 compare equal according to operand_equal_p, but which
3876 have different hash codes. */
3878 {
3879 /* Make sure to include signness in the hash computation. */
3882 }
3885 {
3886 /* It's a commutative expression. We want to hash it the same
3887 however it appears. We do this by first hashing both operands
3888 and then rehashing based on the order of their independent
3889 hashes. */
3894 }
3895 else
3899 }
3901 }
3902 }
3904 bool
3907 {
3908 /* When checking, verify at the outermost operand_equal_p call that
3909 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
3910 hash value. */
3912 {
3914 {
3916 {
3923 }
3925 }
3926 else
3930 }
3933 }
3938 /* Conveinece wrapper around operand_compare class because usually we do
3939 not need to play with the valueizer. */
3941 bool
3943 {
3945 }
3947 namespace inchash
3948 {
3950 /* Generate a hash value for an expression. This can be used iteratively
3951 by passing a previous result as the HSTATE argument.
3953 This function is intended to produce the same hash for expressions which
3954 would compare equal using operand_equal_p. */
3955 void
3957 {
3959 }
3961 }
3962 \f
3963 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3964 with a different signedness or a narrower precision. */
3966 static bool
3968 {
3976 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3977 and see if the inner values are the same. This removes any
3978 signedness comparison, which doesn't matter here. */
3986 /* Discard a single widening conversion from ARG1 and see if the inner
3987 value is the same as ARG0. */
3996 }
3997 \f
3998 /* See if ARG is an expression that is either a comparison or is performing
3999 arithmetic on comparisons. The comparisons must only be comparing
4000 two different values, which will be stored in *CVAL1 and *CVAL2; if
4001 they are nonzero it means that some operands have already been found.
4002 No variables may be used anywhere else in the expression except in the
4003 comparisons.
4005 If this is true, return 1. Otherwise, return zero. */
4007 static bool
4009 {
4013 /* We can handle some of the tcc_expression cases here. */
4022 {
4041 /* First see if we can handle the first operand, then the second. For
4042 the second operand, we know *CVAL1 can't be zero. It must be that
4043 one side of the comparison is each of the values; test for the
4044 case where this isn't true by failing if the two operands
4045 are the same. */
4054 ;
4058 ;
4059 else
4063 ;
4067 ;
4068 else
4075 }
4076 }
4077 \f
4078 /* ARG is a tree that is known to contain just arithmetic operations and
4079 comparisons. Evaluate the operations in the tree substituting NEW0 for
4080 any occurrence of OLD0 as an operand of a comparison and likewise for
4081 NEW1 and OLD1. */
4083 static tree
4086 {
4091 /* We can handle some of the tcc_expression cases here. */
4099 {
4114 {
4133 }
4134 /* Fall through - ??? */
4137 {
4141 /* We need to check both for exact equality and tree equality. The
4142 former will be true if the operand has a side-effect. In that
4143 case, we know the operand occurred exactly once. */
4156 }
4160 }
4161 }
4162 \f
4163 /* Return a tree for the case when the result of an expression is RESULT
4164 converted to TYPE and OMITTED was previously an operand of the expression
4165 but is now not needed (e.g., we folded OMITTED * 0).
4167 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4168 the conversion of RESULT to TYPE. */
4170 tree
4172 {
4175 /* If the resulting operand is an empty statement, just return the omitted
4176 statement casted to void. */
4186 }
4188 /* Return a tree for the case when the result of an expression is RESULT
4189 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4190 of the expression but are now not needed.
4192 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4193 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4194 evaluated before OMITTED2. Otherwise, if neither has side effects,
4195 just do the conversion of RESULT to TYPE. */
4197 tree
4200 {
4209 }
4211 \f
4212 /* Return a simplified tree node for the truth-negation of ARG. This
4213 never alters ARG itself. We assume that ARG is an operation that
4214 returns a truth value (0 or 1).
4216 FIXME: one would think we would fold the result, but it causes
4217 problems with the dominator optimizer. */
4219 static tree
4221 {
4226 /* If this is a comparison, we can simply invert it, except for
4227 floating-point non-equality comparisons, in which case we just
4228 enclose a TRUTH_NOT_EXPR around what we have. */
4231 {
4234 && flag_trapping_math
4248 }
4251 {
4270 /* Here we can invert either operand. We invert the first operand
4271 unless the second operand is a TRUTH_NOT_EXPR in which case our
4272 result is the XOR of the first operand with the inside of the
4273 negation of the second operand. */
4278 else
4301 {
4308 /* A COND_EXPR may have a throw as one operand, which
4309 then has void type. Just leave void operands
4310 as they are. */
4316 }
4328 CASE_CONVERT:
4332 /* fall through */
4354 }
4355 }
4357 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4358 assume that ARG is an operation that returns a truth value (0 or 1
4359 for scalars, 0 or -1 for vectors). Return the folded expression if
4360 folding is successful. Otherwise, return NULL_TREE. */
4362 static tree
4364 {
4367 ? BIT_NOT_EXPR
4370 }
4372 /* Return a simplified tree node for the truth-negation of ARG. This
4373 never alters ARG itself. We assume that ARG is an operation that
4374 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4376 tree
4378 {
4384 ? BIT_NOT_EXPR
4387 }
4388 \f
4389 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4390 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4391 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4392 is the original memory reference used to preserve the alias set of
4393 the access. */
4395 static tree
4399 {
4402 /* Attempt not to lose the access path if possible. */
4404 {
4406 machine_mode nmode;
4408 tree noffset;
4416 && !reversep
4417 && !nreversep
4419 {
4422 }
4423 }
4432 {
4439 }
4454 }
4456 /* Optimize a bit-field compare.
4458 There are two cases: First is a compare against a constant and the
4459 second is a comparison of two items where the fields are at the same
4460 bit position relative to the start of a chunk (byte, halfword, word)
4461 large enough to contain it. In these cases we can avoid the shift
4462 implicit in bitfield extractions.
4464 For constants, we emit a compare of the shifted constant with the
4465 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4466 compared. For two fields at the same position, we do the ANDs with the
4467 similar mask and compare the result of the ANDs.
4469 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4470 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4471 are the left and right operands of the comparison, respectively.
4473 If the optimization described above can be done, we return the resulting
4474 tree. Otherwise we return zero. */
4476 static tree
4479 {
4483 tree unsigned_type;
4486 scalar_int_mode nmode;
4491 tree mask;
4492 tree offset;
4494 /* Get all the information about the extractions being done. If the bit size
4495 is the same as the size of the underlying object, we aren't doing an
4496 extraction at all and so can do nothing. We also don't want to
4497 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4498 then will no longer be able to replace it. */
4513 else
4514 {
4515 /* If this is not a constant, we can only do something if bit positions,
4516 sizes, signedness and storage order are the same. */
4517 rinner
4530 }
4532 /* Honor the C++ memory model and mimic what RTL expansion does. */
4536 {
4540 }
4542 /* See if we can find a mode to refer to this field. We should be able to,
4543 but fail if we can't. */
4551 /* Set signed and unsigned types of the precision of this mode for the
4552 shifts below. */
4555 /* Compute the bit position and size for the new reference and our offset
4556 within it. If the new reference is the same size as the original, we
4557 won't optimize anything, so return zero. */
4567 /* Make the mask to be used against the extracted field. */
4574 {
4578 /* If not comparing with constant, just rework the comparison
4579 and return. */
4587 }
4589 /* Otherwise, we are handling the constant case. See if the constant is too
4590 big for the field. Warn and return a tree for 0 (false) if so. We do
4591 this not only for its own sake, but to avoid having to test for this
4592 error case below. If we didn't, we might generate wrong code.
4594 For unsigned fields, the constant shifted right by the field length should
4595 be all zero. For signed fields, the high-order bits should agree with
4596 the sign bit. */
4599 {
4601 {
4605 }
4606 }
4607 else
4608 {
4611 {
4615 }
4616 }
4621 /* Single-bit compares should always be against zero. */
4623 {
4626 }
4628 /* Make a new bitfield reference, shift the constant over the
4629 appropriate number of bits and mask it with the computed mask
4630 (in case this was a signed field). If we changed it, make a new one. */
4638 mask);
4643 }
4644 \f
4645 /* Subroutine for fold_truth_andor_1: decode a field reference.
4647 If EXP is a comparison reference, we return the innermost reference.
4649 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4650 set to the starting bit number.
4652 If the innermost field can be completely contained in a mode-sized
4653 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4655 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4656 otherwise it is not changed.
4658 *PUNSIGNEDP is set to the signedness of the field.
4660 *PREVERSEP is set to the storage order of the field.
4662 *PMASK is set to the mask used. This is either contained in a
4663 BIT_AND_EXPR or derived from the width of the field.
4665 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4667 Return 0 if this is not a component reference or is one that we can't
4668 do anything with. */
4670 static tree
4675 {
4680 tree unsigned_type;
4683 /* All the optimizations using this function assume integer fields.
4684 There are problems with FP fields since the type_for_size call
4685 below can fail for, e.g., XFmode. */
4689 /* We are interested in the bare arrangement of bits, so strip everything
4690 that doesn't affect the machine mode. However, record the type of the
4691 outermost expression if it may matter below. */
4698 {
4704 }
4715 /* Reject out-of-bound accesses (PR79731). */
4727 /* If the number of bits in the reference is the same as the bitsize of
4728 the outer type, then the outer type gives the signedness. Otherwise
4729 (in case of a small bitfield) the signedness is unchanged. */
4733 /* Compute the mask to access the bitfield. */
4741 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4749 }
4751 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4752 bit positions and MASK is SIGNED. */
4754 static bool
4756 {
4760 /* If this function returns true when the type of the mask is
4761 UNSIGNED, then there will be errors. In particular see
4762 gcc.c-torture/execute/990326-1.c. There does not appear to be
4763 any documentation paper trail as to why this is so. But the pre
4764 wide-int worked with that restriction and it has been preserved
4765 here. */
4770 }
4772 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4773 represents the sign bit of EXP's type. If EXP represents a sign
4774 or zero extension, also test VAL against the unextended type.
4775 The return value is the (sub)expression whose sign bit is VAL,
4776 or NULL_TREE otherwise. */
4778 tree
4780 {
4782 tree t;
4784 /* Tree EXP must have an integral type. */
4789 /* Tree VAL must be an integer constant. */
4798 /* Handle extension from a narrower type. */
4804 }
4806 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4807 to be evaluated unconditionally. */
4809 static bool
4811 {
4812 /* Strip any conversions that don't change the machine mode. */
4821 /* Don't regard global variables as simple. They may be
4822 allocated in ways unknown to the compiler (shared memory,
4823 #pragma weak, etc). */
4826 /* Weakrefs are not safe to be read, since they can be NULL.
4827 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4828 have DECL_WEAK flag set. */
4830 /* Loading a static variable is unduly expensive, but global
4831 registers aren't expensive. */
4833 }
4835 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4836 to be evaluated unconditionally.
4837 I addition to simple_operand_p, we assume that comparisons, conversions,
4838 and logic-not operations are simple, if their operands are simple, too. */
4840 static bool
4842 {
4861 }
4863 \f
4864 /* The following functions are subroutines to fold_range_test and allow it to
4865 try to change a logical combination of comparisons into a range test.
4867 For example, both
4868 X == 2 || X == 3 || X == 4 || X == 5
4869 and
4870 X >= 2 && X <= 5
4871 are converted to
4872 (unsigned) (X - 2) <= 3
4874 We describe each set of comparisons as being either inside or outside
4875 a range, using a variable named like IN_P, and then describe the
4876 range with a lower and upper bound. If one of the bounds is omitted,
4877 it represents either the highest or lowest value of the type.
4879 In the comments below, we represent a range by two numbers in brackets
4880 preceded by a "+" to designate being inside that range, or a "-" to
4881 designate being outside that range, so the condition can be inverted by
4882 flipping the prefix. An omitted bound is represented by a "-". For
4883 example, "- [-, 10]" means being outside the range starting at the lowest
4884 possible value and ending at 10, in other words, being greater than 10.
4885 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4886 always false.
4888 We set up things so that the missing bounds are handled in a consistent
4889 manner so neither a missing bound nor "true" and "false" need to be
4890 handled using a special case. */
4892 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4893 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4894 and UPPER1_P are nonzero if the respective argument is an upper bound
4895 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4896 must be specified for a comparison. ARG1 will be converted to ARG0's
4897 type if both are specified. */
4899 static tree
4902 {
4903 tree tem;
4907 /* If neither arg represents infinity, do the normal operation.
4908 Else, if not a comparison, return infinity. Else handle the special
4909 comparison rules. Note that most of the cases below won't occur, but
4910 are handled for consistency. */
4913 {
4918 }
4923 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4924 for neither. In real maths, we cannot assume open ended ranges are
4925 the same. But, this is computer arithmetic, where numbers are finite.
4926 We can therefore make the transformation of any unbounded range with
4927 the value Z, Z being greater than any representable number. This permits
4928 us to treat unbounded ranges as equal. */
4932 {
4953 }
4956 }
4957 \f
4958 /* Helper routine for make_range. Perform one step for it, return
4959 new expression if the loop should continue or NULL_TREE if it should
4960 stop. */
4962 tree
4966 {
4972 {
4974 /* We can only do something if the range is testing for zero. */
4983 /* We can only do something if the range is testing for zero
4984 and if the second operand is an integer constant. Note that
4985 saying something is "in" the range we make is done by
4986 complementing IN_P since it will set in the initial case of
4987 being not equal to zero; "out" is leaving it alone. */
4994 {
5015 }
5017 /* If this is an unsigned comparison, we also know that EXP is
5018 greater than or equal to zero. We base the range tests we make
5019 on that fact, so we record it here so we can parse existing
5020 range tests. We test arg0_type since often the return type
5021 of, e.g. EQ_EXPR, is boolean. */
5023 {
5027 NULL_TREE))
5032 /* If the high bound is missing, but we have a nonzero low
5033 bound, reverse the range so it goes from zero to the low bound
5034 minus 1. */
5036 {
5041 }
5042 }
5050 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5051 low and high are non-NULL, then normalize will DTRT. */
5054 {
5059 }
5061 /* (-x) IN [a,b] -> x in [-b, -a] */
5073 /* ~ X -> -X - 1 */
5082 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5083 move a constant to the other side. */
5088 /* If EXP is signed, any overflow in the computation is undefined,
5089 so we don't worry about it so long as our computations on
5090 the bounds don't overflow. For unsigned, overflow is defined
5091 and this is exactly the right thing. */
5103 normalize:
5104 /* Check for an unsigned range which has wrapped around the maximum
5105 value thus making n_high < n_low, and normalize it. */
5107 {
5113 /* If the range is of the form +/- [ x+1, x ], we won't
5114 be able to normalize it. But then, it represents the
5115 whole range or the empty set, so make it
5116 +/- [ -, - ]. */
5120 else
5122 }
5123 else
5131 CASE_CONVERT:
5149 /* If we're converting arg0 from an unsigned type, to exp,
5150 a signed type, we will be doing the comparison as unsigned.
5151 The tests above have already verified that LOW and HIGH
5152 are both positive.
5154 So we have to ensure that we will handle large unsigned
5155 values the same way that the current signed bounds treat
5156 negative values. */
5159 {
5160 tree high_positive;
5161 tree equiv_type;
5162 /* For fixed-point modes, we need to pass the saturating flag
5163 as the 2nd parameter. */
5165 equiv_type
5168 else
5169 equiv_type
5172 /* A range without an upper bound is, naturally, unbounded.
5173 Since convert would have cropped a very large value, use
5174 the max value for the destination type. */
5175 high_positive
5182 high_positive),
5185 /* If the low bound is specified, "and" the range with the
5186 range for which the original unsigned value will be
5187 positive. */
5189 {
5192 integer_zero_node),
5193 high_positive))
5197 }
5198 else
5199 {
5200 /* Otherwise, "or" the range with the range of the input
5201 that will be interpreted as negative. */
5204 integer_zero_node),
5205 high_positive))
5209 }
5210 }
5219 }
5220 }
5222 /* Given EXP, a logical expression, set the range it is testing into
5223 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5224 actually being tested. *PLOW and *PHIGH will be made of the same
5225 type as the returned expression. If EXP is not a comparison, we
5226 will most likely not be returning a useful value and range. Set
5227 *STRICT_OVERFLOW_P to true if the return value is only valid
5228 because signed overflow is undefined; otherwise, do not change
5229 *STRICT_OVERFLOW_P. */
5231 tree
5234 {
5242 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5243 and see if we can refine the range. Some of the cases below may not
5244 happen, but it doesn't seem worth worrying about this. We "continue"
5245 the outer loop when we've changed something; otherwise we "break"
5246 the switch, which will "break" the while. */
5252 {
5258 {
5266 }
5275 }
5277 /* If EXP is a constant, we can evaluate whether this is true or false. */
5279 {
5286 }
5290 }
5292 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5293 a bitwise check i.e. when
5294 LOW == 0xXX...X00...0
5295 HIGH == 0xXX...X11...1
5296 Return corresponding mask in MASK and stem in VALUE. */
5298 static bool
5301 {
5324 }
5325 \f
5326 /* Helper routine for build_range_check and match.pd. Return the type to
5327 perform the check or NULL if it shouldn't be optimized. */
5329 tree
5331 {
5332 /* First make sure that arithmetics in this type is valid, then make sure
5333 that it wraps around. */
5338 {
5341 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5342 for the type in question, as we rely on this here. */
5352 else
5354 }
5358 }
5360 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5361 type, TYPE, return an expression to test if EXP is in (or out of, depending
5362 on IN_P) the range. Return 0 if the test couldn't be created. */
5364 tree
5367 {
5370 /* Disable this optimization for function pointer expressions
5371 on targets that require function pointer canonicalization. */
5378 {
5384 }
5406 value);
5409 {
5411 {
5415 }
5417 }
5419 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5421 {
5425 {
5427 {
5430 etype
5432 else
5435 }
5438 }
5439 }
5441 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5442 This requires wrap-around arithmetics for the type of the expression. */
5459 }
5460 \f
5461 /* Return the predecessor of VAL in its type, handling the infinite case. */
5463 static tree
5465 {
5471 else
5474 }
5476 /* Return the successor of VAL in its type, handling the infinite case. */
5478 static tree
5480 {
5486 else
5489 }
5491 /* Given two ranges, see if we can merge them into one. Return 1 if we
5492 can, 0 if we can't. Set the output range into the specified parameters. */
5494 bool
5497 {
5501 tree tem;
5511 /* Make range 0 be the range that starts first, or ends last if they
5512 start at the same value. Swap them if it isn't. */
5515 || (lowequal
5518 {
5522 }
5524 /* If the second range is != high1 where high1 is the type maximum of
5525 the type, try first merging with < high1 range. */
5527 && high1
5534 {
5539 /* Similarly for the second range != low1 where low1 is the type minimum
5540 of the type, try first merging with > low1 range. */
5545 }
5547 /* Now flag two cases, whether the ranges are disjoint or whether the
5548 second range is totally subsumed in the first. Note that the tests
5549 below are simplified by the ones above. */
5555 /* We now have four cases, depending on whether we are including or
5556 excluding the two ranges. */
5558 {
5559 /* If they don't overlap, the result is false. If the second range
5560 is a subset it is the result. Otherwise, the range is from the start
5561 of the second to the end of the first. */
5566 else
5568 }
5571 {
5572 /* If they don't overlap, the result is the first range. If they are
5573 equal, the result is false. If the second range is a subset of the
5574 first, and the ranges begin at the same place, we go from just after
5575 the end of the second range to the end of the first. If the second
5576 range is not a subset of the first, or if it is a subset and both
5577 ranges end at the same place, the range starts at the start of the
5578 first range and ends just before the second range.
5579 Otherwise, we can't describe this as a single range. */
5585 {
5590 {
5591 /* We are in the weird situation where high0 > high1 but
5592 high1 has no successor. Punt. */
5594 }
5595 }
5597 {
5602 {
5603 /* low0 < low1 but low1 has no predecessor. Punt. */
5605 }
5606 }
5607 else
5609 }
5612 {
5613 /* If they don't overlap, the result is the second range. If the second
5614 is a subset of the first, the result is false. Otherwise,
5615 the range starts just after the first range and ends at the
5616 end of the second. */
5621 else
5622 {
5627 {
5628 /* high1 > high0 but high0 has no successor. Punt. */
5630 }
5631 }
5632 }
5634 else
5635 {
5636 /* The case where we are excluding both ranges. Here the complex case
5637 is if they don't overlap. In that case, the only time we have a
5638 range is if they are adjacent. If the second is a subset of the
5639 first, the result is the first. Otherwise, the range to exclude
5640 starts at the beginning of the first range and ends at the end of the
5641 second. */
5643 {
5648 else
5649 {
5650 /* Canonicalize - [min, x] into - [-, x]. */
5653 {
5656 GET_MODE_BITSIZE
5659 /* FALLTHROUGH */
5672 }
5674 /* Canonicalize - [x, max] into - [x, -]. */
5677 {
5680 GET_MODE_BITSIZE
5683 /* FALLTHROUGH */
5699 }
5701 /* The ranges might be also adjacent between the maximum and
5702 minimum values of the given type. For
5703 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5704 return + [x + 1, y - 1]. */
5706 {
5713 }
5714 else
5716 }
5717 }
5720 else
5722 }
5726 }
5727 \f
5729 /* Subroutine of fold, looking inside expressions of the form
5730 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5731 of the COND_EXPR. This function is being used also to optimize
5732 A op B ? C : A, by reversing the comparison first.
5734 Return a folded expression whose code is not a COND_EXPR
5735 anymore, or NULL_TREE if no folding opportunity is found. */
5737 static tree
5740 {
5745 tree tem;
5750 /* If we have A op 0 ? A : -A, consider applying the following
5751 transformations:
5753 A == 0? A : -A same as -A
5754 A != 0? A : -A same as A
5755 A >= 0? A : -A same as abs (A)
5756 A > 0? A : -A same as abs (A)
5757 A <= 0? A : -A same as -abs (A)
5758 A < 0? A : -A same as -abs (A)
5760 None of these transformations work for modes with signed
5761 zeros. If A is +/-0, the first two transformations will
5762 change the sign of the result (from +0 to -0, or vice
5763 versa). The last four will fix the sign of the result,
5764 even though the original expressions could be positive or
5765 negative, depending on the sign of A.
5767 Note that all these transformations are correct if A is
5768 NaN, since the two alternatives (A and -A) are also NaNs. */
5775 /* In the case that A is of the form X-Y, '-A' (arg2) may
5776 have already been folded to Y-X, check for that. */
5784 {
5796 /* Fall through. */
5807 /* FALLTHRU */
5814 {
5815 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5816 is not, invokes UB both in abs and in the negation of it.
5817 So, use ABSU_EXPR instead. */
5822 }
5823 else
5824 {
5827 }
5831 }
5833 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5834 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5835 both transformations are correct when A is NaN: A != 0
5836 is then true, and A == 0 is false. */
5840 {
5845 }
5847 /* Try some transformations of A op B ? A : B.
5849 A == B? A : B same as B
5850 A != B? A : B same as A
5851 A >= B? A : B same as max (A, B)
5852 A > B? A : B same as max (B, A)
5853 A <= B? A : B same as min (A, B)
5854 A < B? A : B same as min (B, A)
5856 As above, these transformations don't work in the presence
5857 of signed zeros. For example, if A and B are zeros of
5858 opposite sign, the first two transformations will change
5859 the sign of the result. In the last four, the original
5860 expressions give different results for (A=+0, B=-0) and
5861 (A=-0, B=+0), but the transformed expressions do not.
5863 The first two transformations are correct if either A or B
5864 is a NaN. In the first transformation, the condition will
5865 be false, and B will indeed be chosen. In the case of the
5866 second transformation, the condition A != B will be true,
5867 and A will be chosen.
5869 The conversions to max() and min() are not correct if B is
5870 a number and A is not. The conditions in the original
5871 expressions will be false, so all four give B. The min()
5872 and max() versions would give a NaN instead. */
5875 /* Avoid these transformations if the COND_EXPR may be used
5876 as an lvalue in the C++ front-end. PR c++/19199. */
5877 && (in_gimple_form
5883 {
5889 {
5898 /* In C++ a ?: expression can be an lvalue, so put the
5899 operand which will be used if they are equal first
5900 so that we can convert this back to the
5901 corresponding COND_EXPR. */
5903 {
5911 }
5918 {
5926 }
5939 }
5940 }
5943 }
5946 \f
5947 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5948 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5949 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5950 false) >= 2)
5951 #endif
5953 /* EXP is some logical combination of boolean tests. See if we can
5954 merge it into some range test. Return the new tree if so. */
5956 static tree
5959 {
5973 /* If op0 is known true or false and this is a short-circuiting
5974 operation we must not merge with op1 since that makes side-effects
5975 unconditional. So special-case this. */
5982 /* If this is an OR operation, invert both sides; we will invert
5983 again at the end. */
5987 /* If both expressions are the same, if we can merge the ranges, and we
5988 can build the range test, return it or it inverted. If one of the
5989 ranges is always true or always false, consider it to be the same
5990 expression as the other. */
5998 {
6002 }
6004 /* On machines where the branch cost is expensive, if this is a
6005 short-circuited branch and the underlying object on both sides
6006 is the same, make a non-short-circuit operation. */
6009 logical_op_non_short_circuit
6012 && !flag_sanitize_coverage
6016 {
6017 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6018 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6019 which cases we can't do this. */
6027 {
6036 {
6039 WARN_STRICT_OVERFLOW_COMPARISON);
6043 }
6044 }
6045 }
6048 }
6049 \f
6050 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6051 bit value. Arrange things so the extra bits will be set to zero if and
6052 only if C is signed-extended to its full width. If MASK is nonzero,
6053 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6055 static tree
6057 {
6060 tree temp;
6065 /* We work by getting just the sign bit into the low-order bit, then
6066 into the high-order bit, then sign-extend. We then XOR that value
6067 with C. */
6071 /* We must use a signed type in order to get an arithmetic right shift.
6072 However, we must also avoid introducing accidental overflows, so that
6073 a subsequent call to integer_zerop will work. Hence we must
6074 do the type conversion here. At this point, the constant is either
6075 zero or one, and the conversion to a signed type can never overflow.
6076 We could get an overflow if this conversion is done anywhere else. */
6085 /* If necessary, convert the type back to match the type of C. */
6090 }
6091 \f
6092 /* For an expression that has the form
6093 (A && B) || ~B
6094 or
6095 (A || B) && ~B,
6096 we can drop one of the inner expressions and simplify to
6097 A || ~B
6098 or
6099 A && ~B
6100 LOC is the location of the resulting expression. OP is the inner
6101 logical operation; the left-hand side in the examples above, while CMPOP
6102 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6103 removing a condition that guards another, as in
6104 (A != NULL && A->...) || A == NULL
6105 which we must not transform. If RHS_ONLY is true, only eliminate the
6106 right-most operand of the inner logical operation. */
6108 static tree
6111 {
6129 {
6132 {
6135 }
6136 }
6138 {
6141 {
6144 }
6145 }
6160 }
6162 /* Find ways of folding logical expressions of LHS and RHS:
6163 Try to merge two comparisons to the same innermost item.
6164 Look for range tests like "ch >= '0' && ch <= '9'".
6165 Look for combinations of simple terms on machines with expensive branches
6166 and evaluate the RHS unconditionally.
6168 For example, if we have p->a == 2 && p->b == 4 and we can make an
6169 object large enough to span both A and B, we can do this with a comparison
6170 against the object ANDed with the a mask.
6172 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6173 operations to do this with one comparison.
6175 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6176 function and the one above.
6178 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6179 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6181 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6182 two operands.
6184 We return the simplified tree or 0 if no optimization is possible. */
6186 static tree
6189 {
6190 /* If this is the "or" of two comparisons, we can do something if
6191 the comparisons are NE_EXPR. If this is the "and", we can do something
6192 if the comparisons are EQ_EXPR. I.e.,
6193 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6195 WANTED_CODE is this operation code. For single bit fields, we can
6196 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6197 comparison for one-bit fields. */
6218 /* Start by getting the comparison codes. Fail if anything is volatile.
6219 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6220 it were surrounded with a NE_EXPR. */
6229 {
6233 }
6236 {
6240 }
6251 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6254 {
6257 {
6262 }
6265 {
6271 }
6272 }
6277 /* If the RHS can be evaluated unconditionally and its operands are
6278 simple, it wins to evaluate the RHS unconditionally on machines
6279 with expensive branches. In this case, this isn't a comparison
6280 that can be merged. */
6287 {
6288 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6299 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6309 }
6311 /* See if the comparisons can be merged. Then get all the parameters for
6312 each side. */
6337 /* It must be true that the inner operation on the lhs of each
6338 comparison must be the same if we are to be able to do anything.
6339 Then see if we have constants. If not, the same must be true for
6340 the rhs's. */
6349 {
6352 }
6357 else
6360 /* If either comparison code is not correct for our logical operation,
6361 fail. However, we can convert a one-bit comparison against zero into
6362 the opposite comparison against that bit being set in the field. */
6366 {
6368 {
6369 /* Make the left operand unsigned, since we are only interested
6370 in the value of one bit. Otherwise we are doing the wrong
6371 thing below. */
6374 }
6375 else
6377 }
6379 /* This is analogous to the code for l_const above. */
6381 {
6383 {
6386 }
6387 else
6389 }
6391 /* See if we can find a mode that contains both fields being compared on
6392 the left. If we can't, fail. Otherwise, update all constants and masks
6393 to be relative to a field of that size. */
6407 {
6410 }
6418 {
6425 {
6429 }
6430 }
6432 {
6439 {
6443 }
6444 }
6446 /* If the right sides are not constant, do the same for it. Also,
6447 disallow this optimization if a size, signedness or storage order
6448 mismatch occurs between the left and right sides. */
6450 {
6454 /* Make sure the two fields on the right
6455 correspond to the left without being swapped. */
6472 {
6475 }
6484 /* Make a mask that corresponds to both fields being compared.
6485 Do this for both items being compared. If the operands are the
6486 same size and the bits being compared are in the same position
6487 then we can do this by masking both and comparing the masked
6488 results. */
6495 {
6509 }
6511 /* There is still another way we can do something: If both pairs of
6512 fields being compared are adjacent, we may be able to make a wider
6513 field containing them both.
6515 Note that we still must mask the lhs/rhs expressions. Furthermore,
6516 the mask must be shifted to account for the shift done by
6517 make_bit_field_ref. */
6526 {
6527 tree type;
6543 /* Convert to the smaller type before masking out unwanted bits. */
6546 {
6548 {
6552 }
6554 {
6558 }
6559 }
6568 }
6571 }
6573 /* Handle the case of comparisons with constants. If there is something in
6574 common between the masks, those bits of the constants must be the same.
6575 If not, the condition is always false. Test for this to avoid generating
6576 incorrect code below. */
6581 {
6583 {
6586 }
6587 else
6588 {
6591 }
6592 }
6597 /* Construct the expression we will return. First get the component
6598 reference we will make. Unless the mask is all ones the width of
6599 that field, perform the mask operation. Then compare with the
6600 merged constant. */
6611 }
6612 \f
6613 /* T is an integer expression that is being multiplied, divided, or taken a
6614 modulus (CODE says which and what kind of divide or modulus) by a
6615 constant C. See if we can eliminate that operation by folding it with
6616 other operations already in T. WIDE_TYPE, if non-null, is a type that
6617 should be used for the computation if wider than our type.
6619 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6620 (X * 2) + (Y * 4). We must, however, be assured that either the original
6621 expression would not overflow or that overflow is undefined for the type
6622 in the language in question.
6624 If we return a non-null expression, it is an equivalent form of the
6625 original computation, but need not be in the original type.
6627 We set *STRICT_OVERFLOW_P to true if the return values depends on
6628 signed overflow being undefined. Otherwise we do not change
6629 *STRICT_OVERFLOW_P. */
6631 static tree
6634 {
6635 /* To avoid exponential search depth, refuse to allow recursion past
6636 three levels. Beyond that (1) it's highly unlikely that we'll find
6637 something interesting and (2) we've probably processed it before
6638 when we built the inner expression. */
6641 tree ret;
6646 depth++;
6648 depth--;
6651 }
6653 static tree
6656 {
6668 /* Don't deal with constants of zero here; they confuse the code below. */
6678 /* Note that we need not handle conditional operations here since fold
6679 already handles those cases. So just do arithmetic here. */
6681 {
6683 /* For a constant, we can always simplify if we are a multiply
6684 or (for divide and modulus) if it is a multiple of our constant. */
6688 {
6691 /* If the multiplication overflowed, we lost information on it.
6692 See PR68142 and PR69845. */
6696 }
6700 /* If op0 is an expression ... */
6706 /* ... and has wrapping overflow, and its type is smaller
6707 than ctype, then we cannot pass through as widening. */
6712 /* ... or this is a truncation (t is narrower than op0),
6713 then we cannot pass through this narrowing. */
6716 /* ... or signedness changes for division or modulus,
6717 then we cannot pass through this conversion. */
6721 /* ... or has undefined overflow while the converted to
6722 type has not, we cannot do the operation in the inner type
6723 as that would introduce undefined overflow. */
6729 /* Pass the constant down and see if we can make a simplification. If
6730 we can, replace this expression with the inner simplification for
6731 possible later conversion to our or some other type. */
6742 /* If widening the type changes it from signed to unsigned, then we
6743 must avoid building ABS_EXPR itself as unsigned. */
6745 {
6749 {
6752 }
6754 }
6755 /* If the constant is negative, we cannot simplify this. */
6758 /* FALLTHROUGH */
6760 /* For division and modulus, type can't be unsigned, as e.g.
6761 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6762 For signed types, even with wrapping overflow, this is fine. */
6771 /* If widening the type changes the signedness, then we can't perform
6772 this optimization as that changes the result. */
6776 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6782 {
6789 }
6793 /* If the second operand is constant, this is a multiplication
6794 or floor division, by a power of two, so we can treat it that
6795 way unless the multiplier or divisor overflows. Signed
6796 left-shift overflow is implementation-defined rather than
6797 undefined in C90, so do not convert signed left shift into
6798 multiplication. */
6801 /* const_binop may not detect overflow correctly,
6802 so check for it explicitly here. */
6811 ctype,
6813 t1),
6818 /* See if we can eliminate the operation on both sides. If we can, we
6819 can return a new PLUS or MINUS. If we can't, the only remaining
6820 cases where we can do anything are if the second operand is a
6821 constant. */
6828 /* If not multiplication, we can only do this if both operands
6829 are divisible by c. */
6832 {
6837 }
6839 /* If this was a subtraction, negate OP1 and set it to be an addition.
6840 This simplifies the logic below. */
6842 {
6844 /* If OP1 was not easily negatable, the constant may be OP0. */
6846 {
6849 }
6850 }
6855 /* If either OP1 or C are negative, this optimization is not safe for
6856 some of the division and remainder types while for others we need
6857 to change the code. */
6859 {
6867 }
6869 /* If it's a multiply or a division/modulus operation of a multiple
6870 of our constant, do the operation and verify it doesn't overflow. */
6874 {
6877 /* We allow the constant to overflow with wrapping semantics. */
6881 }
6882 else
6885 /* If we have an unsigned type, we cannot widen the operation since it
6886 will change the result if the original computation overflowed. */
6890 /* The last case is if we are a multiply. In that case, we can
6891 apply the distributive law to commute the multiply and addition
6892 if the multiplication of the constants doesn't overflow
6893 and overflow is defined. With undefined overflow
6894 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6895 But fold_plusminus_mult_expr would factor back any power-of-two
6896 value so do not distribute in the first place in this case. */
6904 op1);
6909 /* We have a special case here if we are doing something like
6910 (C * 8) % 4 since we know that's zero. */
6913 /* If the multiplication can overflow we cannot optimize this. */
6918 {
6921 }
6923 /* ... fall through ... */
6927 /* If we can extract our operation from the LHS, do so and return a
6928 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6929 do something only if the second operand is a constant. */
6945 /* If these are the same operation types, we can associate them
6946 assuming no overflow. */
6948 {
6963 }
6965 /* If these operations "cancel" each other, we have the main
6966 optimizations of this pass, which occur when either constant is a
6967 multiple of the other, in which case we replace this with either an
6968 operation or CODE or TCODE.
6970 If we have an unsigned type, we cannot do this since it will change
6971 the result if the original computation overflowed. */
6978 {
6981 {
6988 }
6991 {
6998 }
6999 }
7004 }
7007 }
7008 \f
7009 /* Return a node which has the indicated constant VALUE (either 0 or
7010 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7011 and is of the indicated TYPE. */
7013 tree
7015 {
7024 else
7026 }
7029 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7030 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7031 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7032 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7033 COND is the first argument to CODE; otherwise (as in the example
7034 given here), it is the second argument. TYPE is the type of the
7035 original expression. Return NULL_TREE if no simplification is
7036 possible. */
7038 static tree
7043 {
7051 /* Do not move possibly trapping operations into the conditional as this
7052 pessimizes code and causes gimplification issues when applied late. */
7060 {
7064 /* If this operand throws an expression, then it does not make
7065 sense to try to perform a logical or arithmetic operation
7066 involving it. */
7071 }
7074 {
7079 }
7080 else
7081 /* Detect the case of mixing vector and scalar types - bail out. */
7087 /* This transformation is only worthwhile if we don't have to wrap ARG
7088 in a SAVE_EXPR and the operation can be simplified without recursing
7089 on at least one of the branches once its pushed inside the COND_EXPR. */
7098 {
7102 else
7104 }
7106 {
7110 else
7112 }
7114 /* Check that we have simplified at least one of the branches. */
7119 }
7121 \f
7122 /* Subroutine of fold() that checks for the addition of +/- 0.0.
7124 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
7125 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
7126 ADDEND is the same as X.
7128 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7129 and finite. The problematic cases are when X is zero, and its mode
7130 has signed zeros. In the case of rounding towards -infinity,
7131 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7132 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7134 bool
7136 {
7140 /* Don't allow the fold with -fsignaling-nans. */
7144 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7148 /* There is no case that is safe for all rounding modes. */
7152 /* In a vector or complex, we would need to check the sign of all zeros. */
7158 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7162 /* The mode has signed zeros, and we have to honor their sign.
7163 In this situation, there is only one case we can return true for.
7164 X - 0 is the same as X with default rounding. */
7166 }
7168 /* Subroutine of match.pd that optimizes comparisons of a division by
7169 a nonzero integer constant against an integer constant, i.e.
7170 X/C1 op C2.
7172 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7173 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7175 enum tree_code
7178 {
7183 /* We have to do this the hard way to detect unsigned overflow.
7184 prod = int_const_binop (MULT_EXPR, c1, c2); */
7190 {
7194 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7197 }
7199 {
7202 {
7221 }
7222 }
7223 else
7224 {
7225 /* A negative divisor reverses the relational operators. */
7230 {
7249 }
7250 }
7263 }
7266 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7267 equality/inequality test, then return a simplified form of the test
7268 using a sign testing. Otherwise return NULL. TYPE is the desired
7269 result type. */
7271 static tree
7274 tree result_type)
7275 {
7276 /* If this is testing a single bit, we can optimize the test. */
7280 {
7281 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7282 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7286 /* This is only a win if casting to a signed type is cheap,
7287 i.e. when arg00's type is not a partial mode. */
7289 {
7292 result_type,
7295 }
7296 }
7299 }
7301 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7302 equality/inequality test, then return a simplified form of
7303 the test using shifts and logical operations. Otherwise return
7304 NULL. TYPE is the desired result type. */
7306 tree
7309 {
7310 /* If this is testing a single bit, we can optimize the test. */
7314 {
7323 /* First, see if we can fold the single bit test into a sign-bit
7324 test. */
7326 result_type);
7330 /* Otherwise we have (A & C) != 0 where C is a single bit,
7331 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7332 Similarly for (A & C) == 0. */
7334 /* If INNER is a right shift of a constant and it plus BITNUM does
7335 not overflow, adjust BITNUM and INNER. */
7341 {
7344 }
7346 /* If we are going to be able to omit the AND below, we must do our
7347 operations as unsigned. If we must use the AND, we have a choice.
7348 Normally unsigned is faster, but for some machines signed is. */
7366 /* Put the AND last so it can combine with more things. */
7369 /* Make sure to return the proper type. */
7373 }
7375 }
7377 /* Test whether it is preferable two swap two operands, ARG0 and
7378 ARG1, for example because ARG0 is an integer constant and ARG1
7379 isn't. */
7381 bool
7383 {
7397 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7398 for commutative and comparison operators. Ensuring a canonical
7399 form allows the optimizers to find additional redundancies without
7400 having to explicitly check for both orderings. */
7406 /* Put SSA_NAMEs last. */
7412 /* Put variables last. */
7419 }
7422 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7423 means A >= Y && A != MAX, but in this case we know that
7424 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7426 static tree
7428 {
7435 else
7444 {
7447 }
7449 {
7452 }
7453 else
7460 {
7461 /* Convert the pointer types into integer before taking the difference. */
7465 }
7466 else
7473 }
7475 /* Fold a sum or difference of at least one multiplication.
7476 Returns the folded tree or NULL if no simplification could be made. */
7478 static tree
7481 {
7485 /* (A * C) +- (B * C) -> (A+-B) * C.
7486 (A * C) +- A -> A * (C+-1).
7487 We are most concerned about the case where C is a constant,
7488 but other combinations show up during loop reduction. Since
7489 it is not difficult, try all four possibilities. */
7492 {
7495 }
7497 {
7500 }
7501 else
7502 {
7503 /* We cannot generate constant 1 for fract. */
7508 }
7510 {
7513 }
7515 {
7517 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7518 the purpose of this canonicalization. */
7522 {
7525 }
7526 else
7528 }
7529 else
7530 {
7531 /* We cannot generate constant 1 for fract. */
7536 }
7539 /* Prefer factoring a common non-constant. */
7549 /* No identical multiplicands; see if we can find a common
7550 power-of-two factor in non-power-of-two multiplies. This
7551 can help in multi-dimensional array access. */
7553 {
7556 HOST_WIDE_INT tmp;
7558 tree maybe_same;
7560 /* Move min of absolute values to int11. */
7562 {
7567 }
7568 else
7575 /* The remainder should not be a constant, otherwise we
7576 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7577 increased the number of multiplications necessary. */
7579 {
7587 }
7588 }
7595 /* We are neither factoring zero nor minus one. */
7603 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7604 same may be minus one and thus the multiplication may overflow. Perform
7605 the sum operation in an unsigned type. */
7610 /* If the sum evaluated to a constant that is not -INF the multiplication
7611 cannot overflow. */
7618 /* Do not resort to unsigned multiplication because
7619 we lose the no-overflow property of the expression. */
7621 }
7623 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7624 specified by EXPR into the buffer PTR of length LEN bytes.
7625 Return the number of bytes placed in the buffer, or zero
7626 upon failure. */
7628 static int
7630 {
7642 /* Dry run. */
7648 {
7650 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7651 number of bytes. */
7655 {
7662 else
7664 }
7665 else
7669 }
7671 }
7674 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7675 specified by EXPR into the buffer PTR of length LEN bytes.
7676 Return the number of bytes placed in the buffer, or zero
7677 upon failure. */
7679 static int
7681 {
7685 FIXED_VALUE_TYPE value;
7700 }
7703 /* Subroutine of native_encode_expr. Encode the REAL_CST
7704 specified by EXPR into the buffer PTR of length LEN bytes.
7705 Return the number of bytes placed in the buffer, or zero
7706 upon failure. */
7708 static int
7710 {
7716 /* There are always 32 bits in each long, no matter the size of
7717 the hosts long. We handle floating point representations with
7718 up to 192 bits. */
7727 /* Dry run. */
7736 {
7741 {
7748 else
7750 }
7751 else
7752 {
7755 {
7756 /* Reverse bytes within each long, or within the entire float
7757 if it's smaller than a long (for HFmode). */
7760 }
7761 }
7766 }
7768 }
7770 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7771 specified by EXPR into the buffer PTR of length LEN bytes.
7772 Return the number of bytes placed in the buffer, or zero
7773 upon failure. */
7775 static int
7777 {
7779 tree part;
7793 }
7795 /* Like native_encode_vector, but only encode the first COUNT elements.
7796 The other arguments are as for native_encode_vector. */
7798 static int
7801 {
7805 {
7806 /* This is the only case in which elements can be smaller than a byte.
7807 Element 0 is always in the lsb of the containing byte. */
7816 /* Zero the buffer and then set bits later where necessary. */
7825 {
7831 {
7834 }
7835 }
7837 }
7842 {
7844 {
7847 }
7858 }
7860 }
7862 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7863 specified by EXPR into the buffer PTR of length LEN bytes.
7864 Return the number of bytes placed in the buffer, or zero
7865 upon failure. */
7867 static int
7869 {
7874 }
7877 /* Subroutine of native_encode_expr. Encode the STRING_CST
7878 specified by EXPR into the buffer PTR of length LEN bytes.
7879 Return the number of bytes placed in the buffer, or zero
7880 upon failure. */
7882 static int
7884 {
7887 /* Wide-char strings are encoded in target byte-order so native
7888 encoding them is trivial. */
7903 else
7904 {
7907 {
7910 }
7912 }
7914 }
7917 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
7918 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
7919 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
7920 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
7921 sufficient to encode the entire EXPR, or if OFF is out of bounds.
7922 Otherwise, start at byte offset OFF and encode at most LEN bytes.
7923 Return the number of bytes placed in the buffer, or zero upon failure. */
7925 int
7927 {
7928 /* We don't support starting at negative offset and -1 is special. */
7933 {
7954 }
7955 }
7957 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
7958 NON_LVALUE_EXPRs and nops. */
7960 int
7963 {
7964 /* We don't support starting at negative offset and -1 is special. */
7970 {
7985 {
7986 HOST_WIDE_INT min_index;
8004 {
8010 {
8018 }
8020 {
8024 }
8028 do
8029 {
8034 {
8036 {
8039 fieldsize);
8040 }
8042 ptr
8045 fieldsize,
8049 else
8050 {
8053 }
8054 }
8057 {
8058 /* Partial overlap. */
8063 {
8067 fieldsize);
8068 }
8069 else
8070 {
8074 }
8077 }
8079 }
8081 }
8083 }
8086 {
8093 {
8118 {
8125 else
8131 }
8140 {
8141 /* FIXME: Handle PDP endian. */
8161 else
8174 /* If the bitfield does not start at byte boundary, handle
8175 the partial byte at the start. */
8178 {
8180 {
8184 }
8185 else
8186 {
8190 }
8191 }
8192 /* If the bitfield does not end at byte boundary, handle
8193 the partial byte at the end. */
8197 {
8199 {
8204 }
8205 else
8206 {
8211 }
8212 }
8217 else
8218 {
8219 /* Partial overlap. */
8222 {
8225 }
8229 }
8231 }
8236 {
8239 fieldsize,
8242 }
8243 else
8244 {
8245 /* Partial overlap. */
8250 {
8254 fieldsize);
8255 }
8256 else
8257 {
8261 }
8264 }
8265 }
8267 }
8269 }
8270 }
8273 /* Subroutine of native_interpret_expr. Interpret the contents of
8274 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8275 If the buffer cannot be interpreted, return NULL_TREE. */
8277 static tree
8279 {
8289 }
8292 /* Subroutine of native_interpret_expr. Interpret the contents of
8293 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8294 If the buffer cannot be interpreted, return NULL_TREE. */
8296 static tree
8298 {
8301 double_int result;
8302 FIXED_VALUE_TYPE fixed_value;
8312 }
8315 /* Subroutine of native_interpret_expr. Interpret the contents of
8316 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8317 If the buffer cannot be interpreted, return NULL_TREE. */
8319 static tree
8321 {
8325 /* There are always 32 bits in each long, no matter the size of
8326 the hosts long. We handle floating point representations with
8327 up to 192 bits. */
8328 REAL_VALUE_TYPE r;
8338 {
8339 /* Both OFFSET and BYTE index within a long;
8340 bitpos indexes the whole float. */
8343 {
8350 else
8352 }
8353 else
8354 {
8357 {
8358 /* Reverse bytes within each long, or within the entire float
8359 if it's smaller than a long (for HFmode). */
8362 }
8363 }
8367 }
8372 {
8373 /* For floating point values in composite modes, punt if this folding
8374 doesn't preserve bit representation. As the mode doesn't have fixed
8375 precision while GCC pretends it does, there could be valid values that
8376 GCC can't really represent accurately. See PR95450. */
8381 }
8383 }
8386 /* Subroutine of native_interpret_expr. Interpret the contents of
8387 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8388 If the buffer cannot be interpreted, return NULL_TREE. */
8390 static tree
8392 {
8407 }
8409 /* Read a vector of type TYPE from the target memory image given by BYTES,
8410 which contains LEN bytes. The vector is known to be encodable using
8411 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8413 Return the vector on success, otherwise return null. */
8415 static tree
8419 {
8423 {
8424 /* This is the only case in which elements can be smaller than a byte.
8425 Element 0 is always in the lsb of the containing byte. */
8432 {
8439 }
8441 }
8449 {
8455 }
8457 }
8459 /* Subroutine of native_interpret_expr. Interpret the contents of
8460 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8461 If the buffer cannot be interpreted, return NULL_TREE. */
8463 static tree
8465 {
8466 tree etype;
8477 }
8480 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8481 the buffer PTR of length LEN as a constant of type TYPE. For
8482 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8483 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8484 return NULL_TREE. */
8486 tree
8488 {
8490 {
8512 }
8513 }
8515 /* Returns true if we can interpret the contents of a native encoding
8516 as TYPE. */
8518 bool
8520 {
8522 {
8535 }
8536 }
8538 /* Routines for manipulation of native_encode_expr encoded data if the encoded
8539 or extracted constant positions and/or sizes aren't byte aligned. */
8541 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
8542 bits between adjacent elements. AMNT should be within
8543 [0, BITS_PER_UNIT).
8544 Example, AMNT = 2:
8545 00011111|11100000 << 2 = 01111111|10000000
8546 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
8548 void
8551 {
8560 {
8566 {
8569 }
8570 }
8571 }
8573 /* Like shift_bytes_in_array_left but for big-endian.
8574 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
8575 bits between adjacent elements. AMNT should be within
8576 [0, BITS_PER_UNIT).
8577 Example, AMNT = 2:
8578 00011111|11100000 >> 2 = 00000111|11111000
8579 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
8581 void
8584 {
8592 {
8599 }
8600 }
8602 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
8603 directly on the VECTOR_CST encoding, in a way that works for variable-
8604 length vectors. Return the resulting VECTOR_CST on success or null
8605 on failure. */
8607 static tree
8609 {
8621 /* We can only preserve the semantics of a stepped pattern if the new
8622 vector element is an integer of the same size. */
8627 /* The number of bits needed to encode one element from every pattern
8628 of the original vector. */
8629 unsigned int expr_sequence_bits
8632 /* The number of bits needed to encode one element from every pattern
8633 of the result. */
8634 unsigned int type_sequence_bits
8637 /* Don't try to read more bytes than are available, which can happen
8638 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
8639 The general VIEW_CONVERT handling can cope with that case, so there's
8640 no point complicating things here. */
8643 BITS_PER_UNIT);
8648 /* Get enough bytes of EXPR to form the new encoding. */
8656 /* Reencode the bytes as TYPE. */
8660 }
8662 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
8663 TYPE at compile-time. If we're unable to perform the conversion
8664 return NULL_TREE. */
8666 static tree
8668 {
8669 /* We support up to 512-bit values (for V8DFmode). */
8673 /* Check that the host and target are sane. */
8686 }
8688 /* Build an expression for the address of T. Folds away INDIRECT_REF
8689 to avoid confusing the gimplify process. */
8691 tree
8693 {
8694 /* The size of the object is not relevant when talking about its address. */
8699 {
8704 }
8707 {
8712 }
8719 {
8724 }
8725 else
8729 }
8731 /* Build an expression for the address of T. */
8733 tree
8735 {
8739 }
8741 /* Fold a unary expression of code CODE and type TYPE with operand
8742 OP0. Return the folded expression if folding is successful.
8743 Otherwise, return NULL_TREE. */
8745 tree
8747 {
8748 tree tem;
8749 tree arg0;
8757 {
8760 {
8761 /* Don't use STRIP_NOPS, because signedness of argument type
8762 matters. */
8764 }
8765 else
8766 {
8767 /* Strip any conversions that don't change the mode. This
8768 is safe for every expression, except for a comparison
8769 expression because its signedness is derived from its
8770 operands.
8772 Note that this is done as an internal manipulation within
8773 the constant folder, in order to find the simplest
8774 representation of the arguments so that their form can be
8775 studied. In any cases, the appropriate type conversions
8776 should be put back in the tree that will get out of the
8777 constant folder. */
8779 }
8782 {
8785 {
8789 }
8790 }
8791 }
8798 {
8805 {
8819 /* If this was a conversion, and all we did was to move into
8820 inside the COND_EXPR, bring it back out. But leave it if
8821 it is a conversion from integer to integer and the
8822 result precision is no wider than a word since such a
8823 conversion is cheap and may be optimized away by combine,
8824 while it couldn't if it were outside the COND_EXPR. Then return
8825 so we don't get into an infinite recursion loop taking the
8826 conversion out and then back in. */
8838 && (INTEGRAL_TYPE_P
8851 }
8852 }
8855 {
8861 CASE_CONVERT:
8865 {
8866 /* If we have (type) (a CMP b) and type is an integral type, return
8867 new expression involving the new type. Canonicalize
8868 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
8869 non-integral type.
8870 Do not fold the result as that would not simplify further, also
8871 folding again results in recursions. */
8881 }
8883 /* Handle (T *)&A.B.C for A being of type T and B and C
8884 living at offset zero. This occurs frequently in
8885 C++ upcasting and then accessing the base. */
8889 {
8891 tree offset;
8892 machine_mode mode;
8894 tree base
8898 /* If the reference was to a (constant) zero offset, we can use
8899 the address of the base if it has the same base type
8900 as the result type and the pointer type is unqualified. */
8908 }
8912 /* Detect assigning a bitfield. */
8914 && DECL_BIT_FIELD
8916 {
8917 /* Don't leave an assignment inside a conversion
8918 unless assigning a bitfield. */
8920 /* First do the assignment, then return converted constant. */
8925 }
8927 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
8928 constants (if x has signed type, the sign bit cannot be set
8929 in c). This folds extension into the BIT_AND_EXPR.
8930 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
8931 very likely don't have maximal range for their precision and this
8932 transformation effectively doesn't preserve non-maximal ranges. */
8936 {
8947 <= HOST_BITS_PER_WIDE_INT
8949 {
8953 cst &= HOST_WIDE_INT_M1U
8957 && !flag_syntax_only
8960 {
8964 }
8965 }
8967 {
8972 }
8973 }
8975 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
8976 cast (T1)X will fold away. We assume that this happens when X itself
8977 is a cast. */
8981 {
8985 return fold_build_pointer_plus_loc
8987 }
8989 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
8990 of the same precision, and X is an integer type not narrower than
8991 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
8997 {
9003 }
9005 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9006 type of X and Y (integer types only). */
9011 {
9012 /* Be careful not to introduce new overflows. */
9013 tree mult_type;
9016 else
9020 {
9027 }
9028 }
9034 {
9041 }
9052 /* Convert fabs((double)float) into (double)fabsf(float). */
9055 {
9061 targ0));
9062 }
9066 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9085 /* Note that the operand of this must be an int
9086 and its values must be 0 or 1.
9087 ("true" is a fixed value perhaps depending on the language,
9088 but we don't handle values other than 1 correctly yet.) */
9095 /* Fold *&X to X if X is an lvalue. */
9097 {
9104 }
9110 }
9113 /* If the operation was a conversion do _not_ mark a resulting constant
9114 with TREE_OVERFLOW if the original constant was not. These conversions
9115 have implementation defined behavior and retaining the TREE_OVERFLOW
9116 flag here would confuse later passes such as VRP. */
9117 tree
9120 {
9129 }
9131 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9132 operands OP0 and OP1. LOC is the location of the resulting expression.
9133 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9134 Return the folded expression if folding is successful. Otherwise,
9135 return NULL_TREE. */
9136 static tree
9139 {
9140 tree tem;
9142 /* We only do these simplifications if we are optimizing. */
9146 /* Check for things like (A || B) && (A || C). We can convert this
9147 to A || (B && C). Note that either operator can be any of the four
9148 truth and/or operations and the transformation will still be
9149 valid. Also note that we only care about order for the
9150 ANDIF and ORIF operators. If B contains side effects, this
9151 might change the truth-value of A. */
9158 {
9178 /* This case if tricky because we must either have commutative
9179 operators or else A10 must not have side-effects. */
9185 a01);
9186 }
9188 /* See if we can build a range comparison. */
9194 {
9198 }
9202 {
9206 }
9208 /* Check for the possibility of merging component references. If our
9209 lhs is another similar operation, try to merge its rhs with our
9210 rhs. Then try to merge our lhs and rhs. */
9221 logical_op_non_short_circuit
9224 && !flag_sanitize_coverage
9229 {
9236 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9237 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9238 We don't want to pack more than two leafs to a non-IF AND/OR
9239 expression.
9240 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9241 equal to IF-CODE, then we don't want to add right-hand operand.
9242 If the inner right-hand side of left-hand operand has
9243 side-effects, or isn't simple, then we can't add to it,
9244 as otherwise we might destroy if-sequence. */
9247 /* Needed for sequence points to handle trappings, and
9248 side-effects. */
9250 {
9252 arg1);
9254 tem);
9255 }
9256 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9257 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9260 /* Needed for sequence points to handle trappings, and
9261 side-effects. */
9263 {
9268 }
9269 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9270 into (A OR B).
9271 For sequence point consistancy, we need to check for trapping,
9272 and side-effects. */
9276 }
9279 }
9281 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9282 by changing CODE to reduce the magnitude of constants involved in
9283 ARG0 of the comparison.
9284 Returns a canonicalized comparison tree if a simplification was
9285 possible, otherwise returns NULL_TREE.
9286 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9287 valid if signed overflow is undefined. */
9289 static tree
9293 {
9298 /* Match A +- CST code arg1. We can change this only if overflow
9299 is undefined. */
9302 /* In principle pointers also have undefined overflow behavior,
9303 but that causes problems elsewhere. */
9310 /* Identify the constant in arg0 and its sign. */
9314 /* Overflowed constants and zero will cause problems. */
9319 /* See if we can reduce the magnitude of the constant in
9320 arg0 by changing the comparison code. */
9321 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9325 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9329 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9333 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9337 else
9341 /* Now build the constant reduced in magnitude. But not if that
9342 would produce one outside of its types range. */
9358 }
9360 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9361 overflow further. Try to decrease the magnitude of constants involved
9362 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9363 and put sole constants at the second argument position.
9364 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9366 static tree
9369 {
9370 tree t;
9375 /* Try canonicalization by simplifying arg0. */
9380 {
9384 }
9386 /* Try canonicalization by simplifying arg1 using the swapped
9387 comparison. */
9395 }
9397 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9398 space. This is used to avoid issuing overflow warnings for
9399 expressions like &p->x which cannot wrap. */
9401 static bool
9403 {
9410 poly_wide_int wi_offset;
9416 else
9421 precision);
9436 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9437 array. */
9446 }
9448 /* Return a positive integer when the symbol DECL is known to have
9449 a nonzero address, zero when it's known not to (e.g., it's a weak
9450 symbol), and a negative integer when the symbol is not yet in the
9451 symbol table and so whether or not its address is zero is unknown.
9452 For function local objects always return positive integer. */
9453 static int
9455 {
9460 /* Function local objects are never NULL. */
9468 }
9470 /* Subroutine of fold_binary. This routine performs all of the
9471 transformations that are common to the equality/inequality
9472 operators (EQ_EXPR and NE_EXPR) and the ordering operators
9473 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
9474 fold_binary should call fold_binary. Fold a comparison with
9475 tree code CODE and type TYPE with operands OP0 and OP1. Return
9476 the folded comparison or NULL_TREE. */
9478 static tree
9481 {
9491 /* For comparisons of pointers we can decompose it to a compile time
9492 comparison of the base objects and the offsets into the object.
9493 This requires at least one operand being an ADDR_EXPR or a
9494 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
9500 {
9503 machine_mode mode;
9507 /* Get base and offset for the access. Strip ADDR_EXPR for
9508 get_inner_reference, but put it back by stripping INDIRECT_REF
9509 off the base object if possible. indirect_baseN will be true
9510 if baseN is not an address but refers to the object itself. */
9513 {
9514 base0
9520 else
9522 }
9524 {
9528 {
9529 base0
9535 else
9537 }
9540 else
9544 {
9551 }
9552 }
9556 {
9557 base1
9563 else
9565 }
9567 {
9571 {
9572 base1
9578 else
9580 }
9583 else
9587 {
9594 }
9595 }
9597 /* If we have equivalent bases we might be able to simplify. */
9601 {
9602 /* We can fold this expression to a constant if the non-constant
9603 offset parts are equal. */
9607 && (equality_code
9608 || (indirect_base0
9611 {
9617 "occur when comparing P +- C1 with "
9619 WARN_STRICT_OVERFLOW_CONDITIONAL);
9622 {
9660 }
9661 }
9662 /* We can simplify the comparison to a comparison of the variable
9663 offset parts if the constant offset parts are equal.
9664 Be careful to use signed sizetype here because otherwise we
9665 mess with array offsets in the wrong way. This is possible
9666 because pointer arithmetic is restricted to retain within an
9667 object and overflow on pointer differences is undefined as of
9668 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
9670 && (equality_code
9671 || (indirect_base0
9674 {
9675 /* By converting to signed sizetype we cover middle-end pointer
9676 arithmetic which operates on unsigned pointer types of size
9677 type size and ARRAY_REF offsets which are properly sign or
9678 zero extended from their type in case it is narrower than
9679 sizetype. */
9682 else
9686 else
9693 "occur when comparing P +- C1 with "
9695 WARN_STRICT_OVERFLOW_COMPARISON);
9698 }
9699 }
9700 /* For equal offsets we can simplify to a comparison of the
9701 base addresses. */
9703 && (indirect_base0
9705 && (indirect_base1
9710 {
9716 }
9717 /* Comparison between an ordinary (non-weak) symbol and a null
9718 pointer can be eliminated since such symbols must have a non
9719 null address. In C, relational expressions between pointers
9720 to objects and null pointers are undefined. The results
9721 below follow the C++ rules with the additional property that
9722 every object pointer compares greater than a null pointer.
9723 */
9726 /* Avoid folding references to struct members at offset 0 to
9727 prevent tests like '&ptr->firstmember == 0' from getting
9728 eliminated. When ptr is null, although the -> expression
9729 is strictly speaking invalid, GCC retains it as a matter
9730 of QoI. See PR c/44555. */
9733 && indirect_base0
9734 /* The caller guarantees that when one of the arguments is
9735 constant (i.e., null in this case) it is second. */
9737 {
9739 {
9750 }
9751 }
9752 }
9754 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
9755 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
9756 the resulting offset is smaller in absolute value than the
9757 original one and has the same sign. */
9766 {
9771 tree cst;
9773 "occur when combining constants around "
9776 /* Put the constant on the side where it doesn't overflow and is
9777 of lower absolute value and of same sign than before. */
9784 {
9787 variable1,
9791 }
9799 {
9805 variable2);
9806 }
9807 }
9813 /* If we are comparing an expression that just has comparisons
9814 of two integer values, arithmetic expressions of those comparisons,
9815 and constants, we can simplify it. There are only three cases
9816 to check: the two values can either be equal, the first can be
9817 greater, or the second can be greater. Fold the expression for
9818 those three values. Since each value must be 0 or 1, we have
9819 eight possibilities, each of which corresponds to the constant 0
9820 or 1 or one of the six possible comparisons.
9822 This handles common cases like (a > b) == 0 but also handles
9823 expressions like ((x > y) - (y > x)) > 0, which supposedly
9824 occur in macroized code. */
9827 {
9831 /* Don't handle degenerate cases here; they should already
9832 have been handled anyway. */
9841 {
9845 /* We can't just pass T to eval_subst in case cval1 or cval2
9846 was the same as ARG1. */
9848 tree high_result
9852 arg1);
9853 tree equal_result
9857 arg1);
9858 tree low_result
9862 arg1);
9864 /* All three of these results should be 0 or 1. Confirm they are.
9865 Then use those values to select the proper code to use. */
9870 {
9871 /* Make a 3-bit mask with the high-order bit being the
9872 value for `>', the next for '=', and the low for '<'. */
9876 {
9878 /* Always false. */
9899 /* Always true. */
9901 }
9904 }
9905 }
9906 }
9909 }
9912 /* Subroutine of fold_binary. Optimize complex multiplications of the
9913 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9914 argument EXPR represents the expression "z" of type TYPE. */
9916 static tree
9918 {
9923 {
9926 }
9928 {
9931 }
9932 else
9933 {
9937 }
9946 }
9949 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
9950 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
9951 true if successful. */
9953 static bool
9955 {
9960 {
9963 }
9965 {
9971 else
9973 }
9974 else
9980 }
9982 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9983 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9984 NULL_TREE otherwise. */
9986 tree
9988 {
10009 {
10010 HOST_WIDE_INT index;
10016 }
10019 {
10025 }
10026 else
10028 }
10030 /* Try to fold a pointer difference of type TYPE two address expressions of
10031 array references AREF0 and AREF1 using location LOC. Return a
10032 simplified expression for the difference or NULL_TREE. */
10034 static tree
10038 {
10043 /* If the bases are array references as well, recurse. If the bases
10044 are pointer indirections compute the difference of the pointers.
10045 If the bases are equal, we are set. */
10048 && (base_offset
10050 use_pointer_diff)))
10053 && (base_offset
10054 = use_pointer_diff
10064 {
10070 base_offset,
10073 }
10075 }
10077 /* If the real or vector real constant CST of type TYPE has an exact
10078 inverse, return it, else return NULL. */
10080 tree
10082 {
10083 REAL_VALUE_TYPE r;
10084 tree unit_type;
10085 machine_mode mode;
10088 {
10098 {
10102 tree_vector_builder elts;
10107 {
10112 }
10115 }
10119 }
10120 }
10122 /* Mask out the tz least significant bits of X of type TYPE where
10123 tz is the number of trailing zeroes in Y. */
10124 static wide_int
10126 {
10131 }
10133 /* Return true when T is an address and is known to be nonzero.
10134 For floating point we further ensure that T is not denormal.
10135 Similar logic is present in nonzero_address in rtlanal.h.
10137 If the return value is based on the assumption that signed overflow
10138 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10139 change *STRICT_OVERFLOW_P. */
10141 static bool
10143 {
10147 /* Doing something useful for floating point would need more work. */
10153 {
10156 strict_overflow_p);
10162 strict_overflow_p);
10170 }
10173 {
10176 strict_overflow_p);
10184 strict_overflow_p);
10199 strict_overflow_p);
10203 strict_overflow_p);
10206 {
10218 }
10222 }
10224 }
10226 /* Return true when T is an address and is known to be nonzero.
10227 Handle warnings about undefined signed overflow. */
10229 bool
10231 {
10238 "determining that expression is always "
10240 WARN_STRICT_OVERFLOW_MISC);
10242 }
10244 /* Return true if T is known not to be equal to an integer W. */
10246 bool
10248 {
10249 value_range vr;
10251 {
10262 /* If T has some known zero bits and W has any of those bits set,
10263 then T is known not to be equal to W. */
10271 }
10272 }
10274 /* Fold a binary expression of code CODE and type TYPE with operands
10275 OP0 and OP1. LOC is the location of the resulting expression.
10276 Return the folded expression if folding is successful. Otherwise,
10277 return NULL_TREE. */
10279 tree
10282 {
10297 /* Strip any conversions that don't change the mode. This is
10298 safe for every expression, except for a comparison expression
10299 because its signedness is derived from its operands. So, in
10300 the latter case, only strip conversions that don't change the
10301 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10302 preserved.
10304 Note that this is done as an internal manipulation within the
10305 constant folder, in order to find the simplest representation
10306 of the arguments so that their form can be studied. In any
10307 cases, the appropriate type conversions should be put back in
10308 the tree that will get out of the constant folder. */
10311 {
10314 }
10315 else
10316 {
10319 }
10321 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10322 constant but we can't do arithmetic on them. */
10324 {
10327 {
10331 }
10332 }
10334 /* If this is a commutative operation, and ARG0 is a constant, move it
10335 to ARG1 to reduce the number of tests below. */
10340 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10341 to ARG1 to reduce the number of tests below. */
10350 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10352 First check for cases where an arithmetic operation is applied to a
10353 compound, conditional, or comparison operation. Push the arithmetic
10354 operation inside the compound or conditional to see if any folding
10355 can then be done. Convert comparison to conditional for this purpose.
10356 The also optimizes non-constant cases that used to be done in
10357 expand_expr.
10359 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10360 one of the operands is a comparison and the other is a comparison, a
10361 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10362 code below would make the expression more complex. Change it to a
10363 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10364 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10377 {
10381 boolean_type_node,
10389 }
10393 {
10395 {
10400 tem);
10401 }
10403 {
10408 tem);
10409 }
10414 {
10420 }
10425 {
10431 }
10432 }
10435 {
10437 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10440 {
10446 }
10448 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10451 {
10452 tree base;
10453 poly_int64 coffset;
10462 }
10467 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
10473 arg1),
10475 arg0)));
10481 {
10482 /* X + (X / CST) * -CST is X % CST. */
10487 {
10496 cst0));
10497 }
10498 }
10500 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
10501 one. Make sure the type is not saturating and has the signedness of
10502 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10503 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10510 {
10514 }
10517 {
10518 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
10519 (plus (plus (mult) (mult)) (foo)) so that we can
10520 take advantage of the factoring cases below. */
10529 {
10535 else
10548 parg0),
10550 marg)),
10554 return
10560 parg1)));
10561 }
10562 }
10563 else
10564 {
10565 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
10566 to __complex__ ( x, y ). This is not the same for SNaNs or
10567 if signed zeros are involved. */
10571 {
10578 {
10582 {
10588 }
10590 {
10596 }
10597 }
10598 }
10600 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
10601 We associate floats only if the user has specified
10602 -fassociative-math. */
10606 {
10611 {
10612 tree tree0;
10615 }
10616 }
10617 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
10618 We associate floats only if the user has specified
10619 -fassociative-math. */
10623 {
10628 {
10629 tree tree0;
10632 }
10633 }
10634 }
10636 bit_rotate:
10637 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
10638 is a rotate of A by C1 bits. */
10639 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
10640 is a rotate of A by B bits.
10641 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
10642 though in this case CODE must be | and not + or ^, otherwise
10643 it doesn't return A when B is 0. */
10644 {
10646 tree rtype;
10655 /* Only create rotates in complete modes. Other cases are not
10656 expanded properly. */
10659 {
10672 {
10677 }
10682 {
10685 code0 == LSHIFT_EXPR
10688 }
10690 {
10700 {
10704 orig_tree01);
10706 }
10707 }
10711 {
10722 {
10726 orig_tree01);
10728 }
10729 }
10730 }
10731 }
10733 associate:
10734 /* In most languages, can't associate operations on floats through
10735 parentheses. Rather than remember where the parentheses were, we
10736 don't associate floats at all, unless the user has specified
10737 -fassociative-math.
10738 And, we need to make sure type is not saturating. */
10742 {
10748 /* Split both trees into variables, constants, and literals. Then
10749 associate each group together, the constants with literals,
10750 then the result with variables. This increases the chances of
10751 literals being recombined later and of generating relocatable
10752 expressions for the sum of a constant and literal. */
10760 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10764 /* With undefined overflow prefer doing association in a type
10765 which wraps on overflow, if that is one of the operand types. */
10768 {
10776 }
10778 /* With undefined overflow we can only associate constants with one
10779 variable, and constants whose association doesn't overflow. */
10782 {
10784 {
10785 /* ??? If split_tree would handle NEGATE_EXPR we could
10786 simply reject these cases and the allowed cases would
10787 be the var0/minus_var1 ones. */
10793 {
10796 }
10803 {
10806 }
10812 /* The only case we can still associate with two variables
10813 is if they cancel out. */
10817 }
10823 }
10825 /* Only do something if we found more than two objects. Otherwise,
10826 nothing has changed and we risk infinite recursion. */
10834 {
10846 {
10850 }
10852 {
10856 }
10858 /* Preserve the MINUS_EXPR if the negative part of the literal is
10859 greater than the positive part. Otherwise, the multiplicative
10860 folding code (i.e extract_muldiv) may be fooled in case
10861 unsigned constants are subtracted, like in the following
10862 example: ((X*2 + 4) - 8U)/2. */
10864 {
10868 /* But avoid ending up with only negated parts. */
10870 {
10874 }
10875 else
10876 {
10880 }
10881 }
10883 /* Don't introduce overflows through reassociation. */
10888 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
10895 /* Eliminate minus_con0. */
10897 {
10904 else
10907 }
10909 /* Eliminate minus_var0. */
10911 {
10915 else
10918 }
10920 return
10923 }
10924 }
10930 /* Fold &a[i] - &a[j] to i-j. */
10935 {
10939 code
10943 }
10945 /* Further transformations are not for pointers. */
10949 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10952 /* If arg0 is e.g. unsigned int and type is int, then this could
10953 introduce UB, because if A is INT_MIN at runtime, the original
10954 expression can be well defined while the latter is not.
10955 See PR83269. */
10964 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10965 __complex__ ( x, -y ). This is not the same for SNaNs or if
10966 signed zeros are involved. */
10970 {
10977 {
10981 {
10983 arg1r ? arg1r
10988 }
10990 {
10994 arg1i ? arg1i
10997 }
10998 }
10999 }
11001 /* A - B -> A + (-B) if B is easily negatable. */
11005 /* Avoid this transformation if B is a positive REAL_CST. */
11013 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11014 one. Make sure the type is not saturating and has the signedness of
11015 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11016 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11023 {
11027 }
11033 {
11034 /* Transform x * -C into -x * C if x is easily negatable. */
11049 {
11052 "occur when simplifying "
11054 WARN_STRICT_OVERFLOW_MISC);
11056 }
11058 /* Optimize z * conj(z) for integer complex numbers. */
11065 }
11066 else
11067 {
11068 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11069 This is not the same for NaNs or if signed zeros are
11070 involved. */
11076 {
11079 return
11085 return
11090 }
11092 /* Optimize z * conj(z) for floating point complex numbers.
11093 Guarded by flag_unsafe_math_optimizations as non-finite
11094 imaginary components don't produce scalar results. */
11103 }
11107 /* Canonicalize (X & C1) | C2. */
11111 {
11116 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11124 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11126 {
11129 }
11131 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11132 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11133 mode which allows further optimizations. */
11138 {
11143 {
11146 }
11147 }
11150 {
11155 }
11156 }
11158 /* See if this can be simplified into a rotate first. If that
11159 is unsuccessful continue in the association code. */
11163 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11171 /* See if this can be simplified into a rotate first. If that
11172 is unsuccessful continue in the association code. */
11176 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11181 {
11182 tree tem2;
11189 }
11190 /* Fold ~X & 1 as (X & 1) == 0. */
11194 {
11195 tree tem2;
11202 }
11203 /* Fold !X & 1 as X == 0. */
11206 {
11210 }
11212 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11213 multiple of 1 << CST. */
11215 {
11222 }
11224 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11225 bits from CST2. */
11229 {
11231 wide_int masked
11238 {
11239 /* Avoid the transform if arg1 is a mask of some
11240 mode which allows further optimizations. */
11247 }
11248 }
11250 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11253 {
11258 return
11260 }
11265 /* Don't touch a floating-point divide by zero unless the mode
11266 of the constant can represent infinity. */
11272 /* (-A) / (-B) -> A / B */
11284 /* Fall through */
11287 /* Simplify A / (B << N) where A and B are positive and B is
11288 a power of 2, to A >> (N + log2(B)). */
11293 {
11296 {
11304 WARN_STRICT_OVERFLOW_MISC);
11310 }
11311 }
11313 /* Fall through */
11321 /* Convert -A / -B to A / B when the type is signed and overflow is
11322 undefined. */
11326 {
11329 "when distributing negation across "
11331 WARN_STRICT_OVERFLOW_MISC);
11336 }
11340 {
11343 "when distributing negation across "
11345 WARN_STRICT_OVERFLOW_MISC);
11350 }
11352 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11353 operation, EXACT_DIV_EXPR.
11355 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11356 At one time others generated faster code, it's not clear if they do
11357 after the last round to changes to the DIV code in expmed.c. */
11368 {
11372 WARN_STRICT_OVERFLOW_MISC);
11374 }
11386 {
11390 WARN_STRICT_OVERFLOW_MISC);
11392 }
11400 /* Since negative shift count is not well-defined,
11401 don't try to compute it in the compiler. */
11407 /* If we have a rotate of a bit operation with the rotate count and
11408 the second operand of the bit operation both constant,
11409 permute the two operations. */
11415 {
11423 }
11425 /* Two consecutive rotates adding up to the some integer
11426 multiple of the precision of the type can be ignored. */
11442 /* Note that the operands of this must be ints
11443 and their values must be 0 or 1.
11444 ("true" is a fixed value perhaps depending on the language.) */
11445 /* If first arg is constant zero, return it. */
11448 /* FALLTHRU */
11450 /* If either arg is constant true, drop it. */
11454 /* Preserve sequence points. */
11457 /* If second arg is constant zero, result is zero, but first arg
11458 must be evaluated. */
11461 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11462 case will be handled here. */
11466 /* !X && X is always false. */
11470 /* X && !X is always false. */
11475 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11476 means A >= Y && A != MAX, but in this case we know that
11477 A < X <= MAX. */
11481 {
11489 }
11498 /* Note that the operands of this must be ints
11499 and their values must be 0 or true.
11500 ("true" is a fixed value perhaps depending on the language.) */
11501 /* If first arg is constant true, return it. */
11504 /* FALLTHRU */
11506 /* If either arg is constant zero, drop it. */
11510 /* Preserve sequence points. */
11513 /* If second arg is constant true, result is true, but we must
11514 evaluate first arg. */
11517 /* Likewise for first arg, but note this only occurs here for
11518 TRUTH_OR_EXPR. */
11522 /* !X || X is always true. */
11526 /* X || !X is always true. */
11531 /* (X && !Y) || (!X && Y) is X ^ Y */
11534 {
11551 }
11560 /* If the second arg is constant zero, drop it. */
11563 /* If the second arg is constant true, this is a logical inversion. */
11565 {
11568 }
11569 /* Identical arguments cancel to zero. */
11573 /* !X ^ X is always true. */
11578 /* X ^ !X is always true. */
11594 /* bool_var != 1 becomes !bool_var. */
11601 /* bool_var == 0 becomes !bool_var. */
11608 /* !exp != 0 becomes !exp */
11613 /* If this is an EQ or NE comparison with zero and ARG0 is
11614 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11615 two operations, but the latter can be done in one less insn
11616 on machines that have only two-operand insns or on which a
11617 constant cannot be the first operand. */
11620 {
11625 {
11632 arg1);
11633 }
11636 {
11643 arg1);
11644 }
11645 }
11647 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11648 C1 is a valid shift constant, and C2 is a power of two, i.e.
11649 a single bit. */
11653 {
11658 {
11663 /* Check for a valid shift count. */
11665 {
11669 /* If (C2 << C1) doesn't overflow, then
11670 ((X >> C1) & C2) != 0 can be rewritten as
11671 (X & (C2 << C1)) != 0. */
11673 {
11680 }
11681 /* Otherwise, for signed (arithmetic) shifts,
11682 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11683 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11689 /* Otherwise, of unsigned (logical) shifts,
11690 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11691 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11692 else
11696 arg000);
11697 }
11698 }
11699 }
11701 /* If this is a comparison of a field, we may be able to simplify it. */
11704 /* Handle the constant case even without -O
11705 to make sure the warnings are given. */
11707 {
11711 }
11713 /* Optimize comparisons of strlen vs zero to a compare of the
11714 first character of the string vs zero. To wit,
11715 strlen(ptr) == 0 => *ptr == 0
11716 strlen(ptr) != 0 => *ptr != 0
11717 Other cases should reduce to one of these two (or a constant)
11718 due to the return value of strlen being unsigned. */
11720 {
11728 {
11729 tree ptrtype
11731 TYPE_QUAL_CONST));
11737 }
11738 }
11740 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
11741 of X. Similarly fold (X >> C) == 0 into X >= 0. */
11745 {
11750 {
11752 {
11755 }
11758 }
11759 }
11761 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
11762 (X & C) == 0 when C is a single bit. */
11767 {
11774 arg1));
11775 }
11777 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
11778 constant C is a power of two, i.e. a single bit. */
11785 {
11789 }
11791 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
11792 when is C is a power of two, i.e. a single bit. */
11799 {
11805 }
11809 {
11812 }
11816 {
11823 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
11824 operand_equal_p guarantees no side-effects so we don't need
11825 to use omit_one_operand on Z. */
11829 arg10));
11833 arg11));
11837 arg10));
11841 arg11));
11843 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
11846 {
11852 }
11853 }
11855 /* Attempt to simplify equality/inequality comparisons of complex
11856 values. Only lower the comparison if the result is known or
11857 can be simplified to a single scalar comparison. */
11862 {
11867 {
11870 }
11871 else
11872 {
11875 }
11878 {
11881 }
11882 else
11883 {
11886 }
11890 {
11892 {
11897 }
11898 else
11899 {
11904 }
11905 }
11909 {
11911 {
11916 }
11917 else
11918 {
11923 }
11924 }
11925 }
11937 /* Transform comparisons of the form X +- C CMP X. */
11942 {
11947 /* (X - c) > X becomes false. */
11953 /* Likewise (X + c) < X becomes false. */
11959 /* Convert (X - c) <= X to true. */
11966 /* Convert (X + c) >= X to true. */
11972 }
11974 /* If we are comparing an ABS_EXPR with a constant, we can
11975 convert all the cases into explicit comparisons, but they may
11976 well not be faster than doing the ABS and one comparison.
11977 But ABS (X) <= C is a range comparison, which becomes a subtraction
11978 and a comparison, and is probably faster. */
11992 /* Convert ABS_EXPR<x> >= 0 to true. */
11999 {
12002 "when simplifying comparison of "
12004 WARN_STRICT_OVERFLOW_CONDITIONAL);
12007 arg0);
12008 }
12010 /* Convert ABS_EXPR<x> < 0 to false. */
12015 {
12018 "when simplifying comparison of "
12020 WARN_STRICT_OVERFLOW_CONDITIONAL);
12023 arg0);
12024 }
12026 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12027 and similarly for >= into !=. */
12037 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12038 otherwise Y might be >= # of bits in X's type and thus e.g.
12039 (unsigned char) (1 << Y) for Y 15 might be 0.
12040 If the cast is widening, then 1 << Y should have unsigned type,
12041 otherwise if Y is number of bits in the signed shift type minus 1,
12042 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12043 31 might be 0xffffffff80000000. */
12054 {
12060 }
12072 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12073 {
12085 }
12090 /* When pedantic, a compound expression can be neither an lvalue
12091 nor an integer constant expression. */
12094 /* Don't let (0, 0) be null pointer constant. */
12100 /* An ASSERT_EXPR should never be passed to fold_binary. */
12106 }
12108 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12109 ((A & N) + B) & M -> (A + B) & M
12110 Similarly if (N & M) == 0,
12111 ((A | N) + B) & M -> (A + B) & M
12112 and for - instead of + (or unary - instead of +)
12113 and/or ^ instead of |.
12114 If B is constant and (B & M) == 0, fold into A & M.
12116 This function is a helper for match.pd patterns. Return non-NULL
12117 type in which the simplified operation should be performed only
12118 if any optimization is possible.
12120 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12121 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12122 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12123 +/-. */
12124 tree
12129 {
12144 wide_int cst0;
12146 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12147 arg1 (M) is == (1LL << cst) - 1.
12148 Store C into PMOP[0] and D into PMOP[1]. */
12155 {
12162 {
12165 }
12168 /* If C or D is of the form (A & N) where
12169 (N & M) == M, or of the form (A | N) or
12170 (A ^ N) where (N & M) == 0, replace it with A. */
12176 /* If C or D is a N where (N & M) == 0, it can be
12177 omitted (replaced with 0). */
12182 /* Similarly, with C - N where (-N & M) == 0. */
12190 }
12192 /* Only build anything new if we optimized one or both arguments above. */
12198 else
12200 }
12202 /* Used by contains_label_[p1]. */
12204 struct contains_label_data
12205 {
12208 };
12210 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12211 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12212 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12214 static tree
12216 {
12219 {
12230 {
12238 }
12247 }
12248 }
12250 /* Return whether the sub-tree ST contains a label which is accessible from
12251 outside the sub-tree. */
12253 static bool
12255 {
12259 }
12261 /* Fold a ternary expression of code CODE and type TYPE with operands
12262 OP0, OP1, and OP2. Return the folded expression if folding is
12263 successful. Otherwise, return NULL_TREE. */
12265 tree
12268 {
12269 tree tem;
12276 /* If this is a commutative operation, and OP0 is a constant, move it
12277 to OP1 to reduce the number of tests below. */
12286 /* Strip any conversions that don't change the mode. This is safe
12287 for every expression, except for a comparison expression because
12288 its signedness is derived from its operands. So, in the latter
12289 case, only strip conversions that don't change the signedness.
12291 Note that this is done as an internal manipulation within the
12292 constant folder, in order to find the simplest representation of
12293 the arguments so that their form can be studied. In any cases,
12294 the appropriate type conversions should be put back in the tree
12295 that will get out of the constant folder. */
12297 {
12300 }
12303 {
12306 }
12309 {
12312 }
12315 {
12319 {
12325 }
12330 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12331 so all simple results must be passed through pedantic_non_lvalue. */
12333 {
12336 /* Only optimize constant conditions when the selected branch
12337 has the same type as the COND_EXPR. This avoids optimizing
12338 away "c ? x : throw", where the throw has a void type.
12339 Avoid throwing away that operand which contains label. */
12346 }
12348 {
12355 {
12358 {
12366 }
12371 }
12372 }
12374 /* If we have A op B ? A : C, we may be able to convert this to a
12375 simpler expression, depending on the operation and the values
12376 of B and C. Signed zeros prevent all of these transformations,
12377 for reasons given above each one.
12379 Also try swapping the arguments and inverting the conditional. */
12383 {
12387 }
12392 {
12396 {
12400 }
12401 }
12403 /* If the second operand is simpler than the third, swap them
12404 since that produces better jump optimization results. */
12407 {
12409 /* See if this can be inverted. If it can't, possibly because
12410 it was a floating-point inequality comparison, don't do
12411 anything. */
12415 }
12417 /* Convert A ? 1 : 0 to simply A. */
12422 /* If we try to convert OP0 to our type, the
12423 call to fold will try to move the conversion inside
12424 a COND, which will recurse. In that case, the COND_EXPR
12425 is probably the best choice, so leave it alone. */
12429 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12430 over COND_EXPR in cases such as floating point comparisons. */
12439 arg0)));
12441 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12446 {
12447 /* sign_bit_p looks through both zero and sign extensions,
12448 but for this optimization only sign extensions are
12449 usable. */
12452 {
12455 {
12458 }
12460 }
12461 /* sign_bit_p only checks ARG1 bits within A's precision.
12462 If <sign bit of A> has wider type than A, bits outside
12463 of A's precision in <sign bit of A> need to be checked.
12464 If they are all 0, this optimization needs to be done
12465 in unsigned A's type, if they are all 1 in signed A's type,
12466 otherwise this can't be done. */
12472 {
12474 tree tem_type;
12487 {
12490 }
12492 {
12495 }
12496 else
12498 }
12501 return
12507 arg1)));
12508 }
12510 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12511 already handled above. */
12516 {
12526 op1);
12527 }
12529 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12530 is probably obsolete because the first operand should be a
12531 truth value (that's why we have the two cases above), but let's
12532 leave it in until we can confirm this for all front-ends. */
12540 /* operand_equal_p compares just value, not precision, so e.g.
12541 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
12542 second operand 32-bit -128, which is not a power of two (or vice
12543 versa. */
12550 /* Disable the transformations below for vectors, since
12551 fold_binary_op_with_conditional_arg may undo them immediately,
12552 yielding an infinite loop. */
12556 /* Convert A ? B : 0 into A && B if A and B are truth values. */
12565 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
12570 {
12572 /* Only perform transformation if ARG0 is easily inverted. */
12576 ? BIT_IOR_EXPR
12579 op1);
12580 }
12582 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
12587 {
12589 /* Only perform transformation if ARG0 is easily inverted. */
12595 op2);
12596 }
12598 /* Convert A ? 1 : B into A || B if A and B are truth values. */
12610 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
12611 of fold_ternary on them. */
12621 {
12623 unsigned HOST_WIDE_INT width
12634 {
12639 {
12641 {
12646 }
12652 }
12653 }
12654 }
12656 /* On constants we can use native encode/interpret to constant
12657 fold (nearly) all BIT_FIELD_REFs. */
12663 {
12666 /* Limit us to a reasonable amount of work. To relax the
12667 other limitations we need bit-shifting of the buffer
12668 and rounding up the size. */
12672 {
12674 unsigned HOST_WIDE_INT len
12679 {
12684 }
12685 }
12686 }
12691 /* Perform constant folding of BIT_INSERT_EXPR. */
12695 {
12696 /* Build a vector of integers from the tree mask. */
12697 vec_perm_builder builder;
12701 /* Create a vec_perm_indices for the integer vector. */
12706 }
12710 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
12713 {
12719 wide_int tem2
12723 }
12728 {
12730 unsigned HOST_WIDE_INT elsize
12733 {
12739 {
12745 }
12746 }
12747 }
12753 }
12755 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
12756 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
12757 constructor element index of the value returned. If the element is
12758 not found NULL_TREE is returned and *CTOR_IDX is updated to
12759 the index of the element after the ACCESS_INDEX position (which
12760 may be outside of the CTOR array). */
12762 tree
12765 {
12771 {
12774 {
12775 /* Static constructors for variably sized objects makes no sense. */
12778 /* ??? When it is obvious that the range is signed, treat it so. */
12783 {
12785 low_bound
12787 SIGNED);
12788 }
12789 else
12790 {
12793 }
12794 }
12795 }
12799 index_sgn);
12811 {
12812 /* Array constructor might explicitly set index, or specify a range,
12813 or leave index NULL meaning that it is next index after previous
12814 one. */
12816 {
12818 max_index = index
12820 else
12821 {
12824 index_sgn);
12825 max_index
12827 index_sgn);
12829 }
12830 }
12832 {
12838 }
12839 else
12842 /* Do we have match? */
12844 {
12846 {
12850 }
12851 }
12853 /* We're past the element we search for. Note during parsing
12854 the elements might not be sorted.
12855 ??? We should use a binary search and a flag on the
12856 CONSTRUCTOR as to whether elements are sorted in declaration
12857 order. */
12859 }
12863 }
12865 /* Perform constant folding and related simplification of EXPR.
12866 The related simplifications include x*1 => x, x*0 => 0, etc.,
12867 and application of the associative law.
12868 NOP_EXPR conversions may be removed freely (as long as we
12869 are careful not to change the type of the overall expression).
12870 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
12871 but we can constant-fold them if they have constant operands. */
12873 #ifdef ENABLE_FOLD_CHECKING
12874 # define fold(x) fold_1 (x)
12876 static
12877 #endif
12878 tree
12880 {
12884 tree tem;
12887 /* Return right away if a constant. */
12891 /* CALL_EXPR-like objects with variable numbers of operands are
12892 treated specially. */
12894 {
12896 {
12899 }
12901 }
12904 {
12909 {
12927 }
12928 }
12931 {
12933 {
12940 {
12945 }
12948 }
12950 /* Return a VECTOR_CST if possible. */
12952 {
12958 tree val;
12964 }
12972 }
12974 #ifdef ENABLE_FOLD_CHECKING
12975 #undef fold
12982 /* When --enable-checking=fold, compute a digest of expr before
12983 and after actual fold call to see if fold did not accidentally
12984 change original expr. */
12986 tree
12988 {
12989 tree ret;
13009 }
13011 void
13013 {
13024 }
13026 static void
13028 {
13030 }
13032 static void
13035 {
13041 recursive_label:
13051 {
13052 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13060 }
13068 {
13069 /* Allow these fields to be modified. */
13070 tree tmp;
13081 {
13084 }
13085 }
13087 {
13088 /* Allow TREE_NO_WARNING to be set. Perhaps we shouldn't allow that
13089 and change builtins.c etc. instead - see PR89543. */
13095 }
13106 {
13109 {
13125 }
13129 {
13142 }
13159 {
13165 }
13168 {
13170 {
13173 }
13175 }
13186 {
13189 }
13199 }
13200 }
13202 /* Helper function for outputting the checksum of a tree T. When
13203 debugging with gdb, you can "define mynext" to be "next" followed
13204 by "call debug_fold_checksum (op0)", then just trace down till the
13205 outputs differ. */
13207 DEBUG_FUNCTION void
13209 {
13224 }
13226 #endif
13228 /* Fold a unary tree expression with code CODE of type TYPE with an
13229 operand OP0. LOC is the location of the resulting expression.
13230 Return a folded expression if successful. Otherwise, return a tree
13231 expression with code CODE of type TYPE with an operand OP0. */
13233 tree
13236 {
13237 tree tem;
13238 #ifdef ENABLE_FOLD_CHECKING
13247 #endif
13253 #ifdef ENABLE_FOLD_CHECKING
13260 #endif
13262 }
13264 /* Fold a binary tree expression with code CODE of type TYPE with
13265 operands OP0 and OP1. LOC is the location of the resulting
13266 expression. Return a folded expression if successful. Otherwise,
13267 return a tree expression with code CODE of type TYPE with operands
13268 OP0 and OP1. */
13270 tree
13273 MEM_STAT_DECL)
13274 {
13275 tree tem;
13276 #ifdef ENABLE_FOLD_CHECKING
13293 #endif
13299 #ifdef ENABLE_FOLD_CHECKING
13314 #endif
13316 }
13318 /* Fold a ternary tree expression with code CODE of type TYPE with
13319 operands OP0, OP1, and OP2. Return a folded expression if
13320 successful. Otherwise, return a tree expression with code CODE of
13321 type TYPE with operands OP0, OP1, and OP2. */
13323 tree
13326 {
13327 tree tem;
13328 #ifdef ENABLE_FOLD_CHECKING
13352 #endif
13359 #ifdef ENABLE_FOLD_CHECKING
13382 #endif
13384 }
13386 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13387 arguments in ARGARRAY, and a null static chain.
13388 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13389 of type TYPE from the given operands as constructed by build_call_array. */
13391 tree
13394 {
13395 tree tem;
13396 #ifdef ENABLE_FOLD_CHECKING
13415 #endif
13421 #ifdef ENABLE_FOLD_CHECKING
13437 #endif
13439 }
13441 /* Perform constant folding and related simplification of initializer
13442 expression EXPR. These behave identically to "fold_buildN" but ignore
13443 potential run-time traps and exceptions that fold must preserve. */
13445 #define START_FOLD_INIT \
13446 int saved_signaling_nans = flag_signaling_nans;\
13447 int saved_trapping_math = flag_trapping_math;\
13448 int saved_rounding_math = flag_rounding_math;\
13449 int saved_trapv = flag_trapv;\
13450 int saved_folding_initializer = folding_initializer;\
13451 flag_signaling_nans = 0;\
13452 flag_trapping_math = 0;\
13453 flag_rounding_math = 0;\
13454 flag_trapv = 0;\
13455 folding_initializer = 1;
13457 #define END_FOLD_INIT \
13458 flag_signaling_nans = saved_signaling_nans;\
13459 flag_trapping_math = saved_trapping_math;\
13460 flag_rounding_math = saved_rounding_math;\
13461 flag_trapv = saved_trapv;\
13462 folding_initializer = saved_folding_initializer;
13464 tree
13467 {
13468 tree result;
13469 START_FOLD_INIT;
13473 END_FOLD_INIT;
13475 }
13477 tree
13480 {
13481 tree result;
13482 START_FOLD_INIT;
13486 END_FOLD_INIT;
13488 }
13490 tree
13493 {
13494 tree result;
13495 START_FOLD_INIT;
13499 END_FOLD_INIT;
13501 }
13503 #undef START_FOLD_INIT
13504 #undef END_FOLD_INIT
13506 /* Determine if first argument is a multiple of second argument. Return 0 if
13507 it is not, or we cannot easily determined it to be.
13509 An example of the sort of thing we care about (at this point; this routine
13510 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13511 fold cases do now) is discovering that
13513 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13515 is a multiple of
13517 SAVE_EXPR (J * 8)
13519 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13521 This code also handles discovering that
13523 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13525 is a multiple of 8 so we don't have to worry about dealing with a
13526 possible remainder.
13528 Note that we *look* inside a SAVE_EXPR only to determine how it was
13529 calculated; it is not safe for fold to do much of anything else with the
13530 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13531 at run time. For example, the latter example above *cannot* be implemented
13532 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13533 evaluation time of the original SAVE_EXPR is not necessarily the same at
13534 the time the new expression is evaluated. The only optimization of this
13535 sort that would be valid is changing
13537 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13539 divided by 8 to
13541 SAVE_EXPR (I) * SAVE_EXPR (J)
13543 (where the same SAVE_EXPR (J) is used in the original and the
13544 transformed version). */
13546 int
13548 {
13559 {
13561 /* Bitwise and provides a power of two multiple. If the mask is
13562 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13570 {
13576 {
13579 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
13581 {
13585 {
13588 }
13589 }
13591 }
13592 }
13597 /* It is impossible to prove if op0 - op1 is multiple of bottom
13598 precisely, so be conservative here checking if both op0 and op1
13599 are multiple of bottom. Note we check the second operand first
13600 since it's usually simpler. */
13605 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
13606 as op0 - 3 if the expression has unsigned type. For example,
13607 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
13617 {
13619 /* const_binop may not detect overflow correctly,
13620 so check for it explicitly here. */
13628 }
13632 /* Can't handle conversions from non-integral or wider integral type. */
13638 /* fall through */
13655 SIGNED);
13661 {
13664 /* Check for special cases to see if top is defined as multiple
13665 of bottom:
13667 top = (X & ~(bottom - 1) ; bottom is power of 2
13669 or
13671 Y = X % bottom
13672 top = X - Y. */
13691 }
13693 /* fall through */
13701 }
13702 }
13704 #define tree_expr_nonnegative_warnv_p(X, Y) \
13707 #define RECURSE(X) \
13708 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
13710 /* Return true if CODE or TYPE is known to be non-negative. */
13712 static bool
13714 {
13717 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13718 have a signed:1 type (where the value is -1 and 0). */
13721 }
13723 /* Return true if (CODE OP0) is known to be non-negative. If the return
13724 value is based on the assumption that signed overflow is undefined,
13725 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13726 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13728 bool
13731 {
13736 {
13738 /* We can't return 1 if flag_wrapv is set because
13739 ABS_EXPR<INT_MIN> = INT_MIN. */
13743 {
13746 }
13754 CASE_CONVERT:
13755 {
13760 {
13764 {
13768 }
13769 }
13771 {
13777 }
13778 }
13783 }
13785 /* We don't know sign of `t', so be conservative and return false. */
13787 }
13789 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13790 value is based on the assumption that signed overflow is undefined,
13791 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13792 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13794 bool
13798 {
13803 {
13809 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13810 both unsigned and at least 2 bits shorter than the result. */
13814 {
13819 {
13823 }
13824 }
13829 {
13830 /* x * x is always non-negative for floating point x
13831 or without overflow. */
13834 {
13839 }
13840 }
13842 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
13843 both unsigned and their total bits is shorter than the result. */
13847 {
13866 {
13876 }
13877 }
13904 }
13906 /* We don't know sign of `t', so be conservative and return false. */
13908 }
13910 /* Return true if T is known to be non-negative. If the return
13911 value is based on the assumption that signed overflow is undefined,
13912 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13913 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13915 bool
13917 {
13922 {
13936 /* Limit the depth of recursion to avoid quadratic behavior.
13937 This is expected to catch almost all occurrences in practice.
13938 If this code misses important cases that unbounded recursion
13939 would not, passes that need this information could be revised
13940 to provide it through dataflow propagation. */
13948 }
13949 }
13951 /* Return true if T is known to be non-negative. If the return
13952 value is based on the assumption that signed overflow is undefined,
13953 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13954 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13956 bool
13959 {
13961 {
13962 CASE_CFN_ACOS:
13963 CASE_CFN_ACOSH:
13964 CASE_CFN_CABS:
13965 CASE_CFN_COSH:
13966 CASE_CFN_ERFC:
13967 CASE_CFN_EXP:
13968 CASE_CFN_EXP10:
13969 CASE_CFN_EXP2:
13970 CASE_CFN_FABS:
13971 CASE_CFN_FDIM:
13972 CASE_CFN_HYPOT:
13973 CASE_CFN_POW10:
13974 CASE_CFN_FFS:
13975 CASE_CFN_PARITY:
13976 CASE_CFN_POPCOUNT:
13977 CASE_CFN_CLZ:
13978 CASE_CFN_CLRSB:
13983 /* Always true. */
13986 CASE_CFN_SQRT:
13987 CASE_CFN_SQRT_FN:
13988 /* sqrt(-0.0) is -0.0. */
13993 CASE_CFN_ASINH:
13994 CASE_CFN_ATAN:
13995 CASE_CFN_ATANH:
13996 CASE_CFN_CBRT:
13997 CASE_CFN_CEIL:
13998 CASE_CFN_CEIL_FN:
13999 CASE_CFN_ERF:
14000 CASE_CFN_EXPM1:
14001 CASE_CFN_FLOOR:
14002 CASE_CFN_FLOOR_FN:
14003 CASE_CFN_FMOD:
14004 CASE_CFN_FREXP:
14005 CASE_CFN_ICEIL:
14006 CASE_CFN_IFLOOR:
14007 CASE_CFN_IRINT:
14008 CASE_CFN_IROUND:
14009 CASE_CFN_LCEIL:
14010 CASE_CFN_LDEXP:
14011 CASE_CFN_LFLOOR:
14012 CASE_CFN_LLCEIL:
14013 CASE_CFN_LLFLOOR:
14014 CASE_CFN_LLRINT:
14015 CASE_CFN_LLROUND:
14016 CASE_CFN_LRINT:
14017 CASE_CFN_LROUND:
14018 CASE_CFN_MODF:
14019 CASE_CFN_NEARBYINT:
14020 CASE_CFN_NEARBYINT_FN:
14021 CASE_CFN_RINT:
14022 CASE_CFN_RINT_FN:
14023 CASE_CFN_ROUND:
14024 CASE_CFN_ROUND_FN:
14025 CASE_CFN_ROUNDEVEN:
14026 CASE_CFN_ROUNDEVEN_FN:
14027 CASE_CFN_SCALB:
14028 CASE_CFN_SCALBLN:
14029 CASE_CFN_SCALBN:
14030 CASE_CFN_SIGNBIT:
14031 CASE_CFN_SIGNIFICAND:
14032 CASE_CFN_SINH:
14033 CASE_CFN_TANH:
14034 CASE_CFN_TRUNC:
14035 CASE_CFN_TRUNC_FN:
14036 /* True if the 1st argument is nonnegative. */
14039 CASE_CFN_FMAX:
14040 CASE_CFN_FMAX_FN:
14041 /* True if the 1st OR 2nd arguments are nonnegative. */
14044 CASE_CFN_FMIN:
14045 CASE_CFN_FMIN_FN:
14046 /* True if the 1st AND 2nd arguments are nonnegative. */
14049 CASE_CFN_COPYSIGN:
14050 CASE_CFN_COPYSIGN_FN:
14051 /* True if the 2nd argument is nonnegative. */
14054 CASE_CFN_POWI:
14055 /* True if the 1st argument is nonnegative or the second
14056 argument is an even integer. */
14062 CASE_CFN_POW:
14063 /* True if the 1st argument is nonnegative or the second
14064 argument is an even integer valued real. */
14066 {
14067 REAL_VALUE_TYPE c;
14068 HOST_WIDE_INT n;
14073 {
14074 REAL_VALUE_TYPE cint;
14078 }
14079 }
14084 }
14086 }
14088 /* Return true if T is known to be non-negative. If the return
14089 value is based on the assumption that signed overflow is undefined,
14090 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14091 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14093 static bool
14095 {
14101 {
14103 {
14107 /* If the initializer is non-void, then it's a normal expression
14108 that will be assigned to the slot. */
14112 /* Otherwise, the initializer sets the slot in some way. One common
14113 way is an assignment statement at the end of the initializer. */
14115 {
14123 else
14125 }
14131 }
14134 {
14140 arg0,
14141 arg1,
14143 }
14156 }
14157 }
14159 #undef RECURSE
14160 #undef tree_expr_nonnegative_warnv_p
14162 /* Return true if T is known to be non-negative. If the return
14163 value is based on the assumption that signed overflow is undefined,
14164 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14165 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14167 bool
14169 {
14176 {
14198 }
14201 {
14227 }
14228 }
14230 /* Return true if `t' is known to be non-negative. Handle warnings
14231 about undefined signed overflow. */
14233 bool
14235 {
14242 "determining that expression is always "
14244 WARN_STRICT_OVERFLOW_MISC);
14246 }
14249 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14250 For floating point we further ensure that T is not denormal.
14251 Similar logic is present in nonzero_address in rtlanal.h.
14253 If the return value is based on the assumption that signed overflow
14254 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14255 change *STRICT_OVERFLOW_P. */
14257 bool
14260 {
14262 {
14265 strict_overflow_p);
14268 {
14274 strict_overflow_p));
14275 }
14280 strict_overflow_p);
14284 }
14287 }
14289 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14290 For floating point we further ensure that T is not denormal.
14291 Similar logic is present in nonzero_address in rtlanal.h.
14293 If the return value is based on the assumption that signed overflow
14294 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14295 change *STRICT_OVERFLOW_P. */
14297 bool
14299 tree type,
14300 tree op0,
14302 {
14305 {
14309 {
14310 /* With the presence of negative values it is hard
14311 to say something. */
14318 /* One of operands must be positive and the other non-negative. */
14319 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14320 overflows, on a twos-complement machine the sum of two
14321 nonnegative numbers can never be zero. */
14323 strict_overflow_p)
14325 strict_overflow_p));
14326 }
14331 {
14333 strict_overflow_p)
14335 strict_overflow_p))
14336 {
14339 }
14340 }
14349 {
14352 }
14359 {
14363 /* When both operands are nonzero, then MAX must be too. */
14365 strict_overflow_p))
14368 /* MAX where operand 0 is positive is positive. */
14370 strict_overflow_p);
14371 }
14372 /* MAX where operand 1 is positive is positive. */
14377 {
14381 }
14386 strict_overflow_p)
14388 strict_overflow_p));
14392 }
14395 }
14397 /* Return true when T is an address and is known to be nonzero.
14398 For floating point we further ensure that T is not denormal.
14399 Similar logic is present in nonzero_address in rtlanal.h.
14401 If the return value is based on the assumption that signed overflow
14402 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14403 change *STRICT_OVERFLOW_P. */
14405 bool
14407 {
14410 {
14415 {
14427 /* For objects in symbol table check if we know they are non-zero.
14428 Don't do anything for variables and functions before symtab is built;
14429 it is quite possible that they will be declared weak later. */
14434 /* Constants are never weak. */
14439 }
14447 {
14451 }
14461 }
14463 }
14465 #define integer_valued_real_p(X) \
14468 #define RECURSE(X) \
14469 ((integer_valued_real_p) (X, depth + 1))
14471 /* Return true if the floating point result of (CODE OP0) has an
14472 integer value. We also allow +Inf, -Inf and NaN to be considered
14473 integer values. Return false for signaling NaN.
14475 DEPTH is the current nesting depth of the query. */
14477 bool
14479 {
14481 {
14488 CASE_CONVERT:
14489 {
14496 }
14500 }
14502 }
14504 /* Return true if the floating point result of (CODE OP0 OP1) has an
14505 integer value. We also allow +Inf, -Inf and NaN to be considered
14506 integer values. Return false for signaling NaN.
14508 DEPTH is the current nesting depth of the query. */
14510 bool
14512 {
14514 {
14524 }
14526 }
14528 /* Return true if the floating point result of calling FNDECL with arguments
14529 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
14530 considered integer values. Return false for signaling NaN. If FNDECL
14531 takes fewer than 2 arguments, the remaining ARGn are null.
14533 DEPTH is the current nesting depth of the query. */
14535 bool
14537 {
14539 {
14540 CASE_CFN_CEIL:
14541 CASE_CFN_CEIL_FN:
14542 CASE_CFN_FLOOR:
14543 CASE_CFN_FLOOR_FN:
14544 CASE_CFN_NEARBYINT:
14545 CASE_CFN_NEARBYINT_FN:
14546 CASE_CFN_RINT:
14547 CASE_CFN_RINT_FN:
14548 CASE_CFN_ROUND:
14549 CASE_CFN_ROUND_FN:
14550 CASE_CFN_ROUNDEVEN:
14551 CASE_CFN_ROUNDEVEN_FN:
14552 CASE_CFN_TRUNC:
14553 CASE_CFN_TRUNC_FN:
14556 CASE_CFN_FMIN:
14557 CASE_CFN_FMIN_FN:
14558 CASE_CFN_FMAX:
14559 CASE_CFN_FMAX_FN:
14564 }
14566 }
14568 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
14569 has an integer value. We also allow +Inf, -Inf and NaN to be
14570 considered integer values. Return false for signaling NaN.
14572 DEPTH is the current nesting depth of the query. */
14574 bool
14576 {
14578 {
14586 /* Limit the depth of recursion to avoid quadratic behavior.
14587 This is expected to catch almost all occurrences in practice.
14588 If this code misses important cases that unbounded recursion
14589 would not, passes that need this information could be revised
14590 to provide it through dataflow propagation. */
14594 depth));
14598 }
14600 }
14602 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
14603 has an integer value. We also allow +Inf, -Inf and NaN to be
14604 considered integer values. Return false for signaling NaN.
14606 DEPTH is the current nesting depth of the query. */
14608 static bool
14610 {
14612 {
14623 }
14625 }
14627 #undef RECURSE
14628 #undef integer_valued_real_p
14630 /* Return true if the floating point expression T has an integer value.
14631 We also allow +Inf, -Inf and NaN to be considered integer values.
14632 Return false for signaling NaN.
14634 DEPTH is the current nesting depth of the query. */
14636 bool
14638 {
14646 {
14662 }
14665 {
14671 {
14680 }
14684 }
14685 }
14687 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14688 attempt to fold the expression to a constant without modifying TYPE,
14689 OP0 or OP1.
14691 If the expression could be simplified to a constant, then return
14692 the constant. If the expression would not be simplified to a
14693 constant, then return NULL_TREE. */
14695 tree
14697 {
14700 }
14702 /* Given the components of a unary expression CODE, TYPE and OP0,
14703 attempt to fold the expression to a constant without modifying
14704 TYPE or OP0.
14706 If the expression could be simplified to a constant, then return
14707 the constant. If the expression would not be simplified to a
14708 constant, then return NULL_TREE. */
14710 tree
14712 {
14715 }
14717 /* If EXP represents referencing an element in a constant string
14718 (either via pointer arithmetic or array indexing), return the
14719 tree representing the value accessed, otherwise return NULL. */
14721 tree
14723 {
14727 {
14729 tree index;
14730 tree string;
14735 else
14736 {
14740 /* Optimize the special-case of a zero lower bound.
14742 We convert the low_bound to sizetype to avoid some problems
14743 with constant folding. (E.g. suppose the lower bound is 1,
14744 and its mode is QI. Without the conversion,l (ARRAY
14745 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14746 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
14752 }
14754 scalar_int_mode char_mode;
14766 }
14768 }
14770 /* Folds a read from vector element at IDX of vector ARG. */
14772 tree
14774 {
14779 {
14783 {
14787 }
14788 }
14790 }
14792 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14793 an integer constant, real, or fixed-point constant.
14795 TYPE is the type of the result. */
14797 static tree
14799 {
14803 {
14809 {
14810 FIXED_VALUE_TYPE f;
14815 /* Propagate overflow flags. */
14819 }
14823 {
14830 }
14833 }
14836 }
14838 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14839 an integer constant or real constant.
14841 TYPE is the type of the result. */
14843 tree
14845 {
14849 {
14851 {
14852 /* If the value is unsigned or non-negative, then the absolute value
14853 is the same as the ordinary value. */
14857 ;
14859 /* If the value is negative, then the absolute value is
14860 its negation. */
14861 else
14864 /* Force to the destination type, set TREE_OVERFLOW for signed
14865 TYPE only. */
14867 }
14873 else
14879 }
14882 }
14884 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14885 constant. TYPE is the type of the result. */
14887 static tree
14889 {
14893 }
14895 /* Given CODE, a relational operator, the target type, TYPE and two
14896 constant operands OP0 and OP1, return the result of the
14897 relational operation. If the result is not a compile time
14898 constant, then return NULL_TREE. */
14900 static tree
14902 {
14905 /* From here on, the only cases we handle are when the result is
14906 known to be a constant. */
14909 {
14913 /* Handle the cases where either operand is a NaN. */
14915 {
14917 {
14945 }
14948 }
14951 }
14954 {
14958 }
14960 /* Handle equality/inequality of complex constants. */
14962 {
14973 else
14975 }
14978 {
14980 {
14981 /* Have vector comparison with scalar boolean result. */
14989 {
14997 }
14999 }
15000 tree_vector_builder elts;
15005 {
15018 }
15021 }
15023 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15025 To compute GT, swap the arguments and do LT.
15026 To compute GE, do LT and invert the result.
15027 To compute LE, swap the arguments, do LT and invert the result.
15028 To compute NE, do EQ and invert the result.
15030 Therefore, the code below must handle only EQ and LT. */
15033 {
15036 }
15038 /* Note that it is safe to invert for real values here because we
15039 have already handled the one case that it matters. */
15043 {
15046 }
15048 /* Compute a result for LT or EQ if args permit;
15049 Otherwise return T. */
15051 {
15054 else
15056 }
15057 else
15063 }
15065 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15066 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15067 itself. */
15069 tree
15071 {
15072 /* If the expression does not have side effects then we don't have to wrap
15073 it with a cleanup point expression. */
15077 /* If the expression is a return, check to see if the expression inside the
15078 return has no side effects or the right hand side of the modify expression
15079 inside the return. If either don't have side effects set we don't need to
15080 wrap the expression in a cleanup point expression. Note we don't check the
15081 left hand side of the modify because it should always be a return decl. */
15083 {
15090 }
15093 }
15095 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15096 of an indirection through OP0, or NULL_TREE if no simplification is
15097 possible. */
15099 tree
15101 {
15103 tree subtype;
15104 poly_uint64 const_op01;
15113 {
15117 /* *&CONST_DECL -> to the value of the const decl. */
15120 /* *&p => p; make sure to handle *&"str"[cst] here. */
15122 {
15126 else
15128 }
15129 /* *(foo *)&fooarray => fooarray[0] */
15132 && (!in_gimple_form
15134 {
15144 }
15145 /* *(foo *)&complexfoo => __real__ complexfoo */
15149 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15152 {
15156 index);
15157 }
15158 }
15162 {
15168 {
15169 tree op00type;
15173 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15176 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
15177 but we want to treat offsets with MSB set as negative.
15178 For the code below negative offsets are invalid and
15179 TYPE_SIZE of the element is something unsigned, so
15180 check whether op01 fits into poly_int64, which implies
15181 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
15182 then just use poly_uint64 because we want to treat the
15183 value as unsigned. */
15185 {
15187 poly_uint64 max_offset
15191 {
15196 }
15197 }
15198 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15201 {
15203 const_op01))
15205 }
15206 /* ((foo *)&fooarray)[1] => fooarray[1] */
15209 {
15218 {
15223 }
15224 }
15225 }
15226 }
15228 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15231 && (!in_gimple_form
15233 {
15234 tree type_domain;
15244 NULL_TREE);
15245 }
15248 }
15250 /* Builds an expression for an indirection through T, simplifying some
15251 cases. */
15253 tree
15255 {
15263 }
15265 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15267 tree
15269 {
15274 else
15276 }
15278 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15279 whose result is ignored. The type of the returned tree need not be
15280 the same as the original expression. */
15282 tree
15284 {
15290 {
15301 else
15307 {
15323 }
15328 }
15329 }
15331 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
15333 tree
15335 {
15341 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15342 have to do anything. Only do this when we are not given a const,
15343 because in that case, this check is more expensive than just
15344 doing it. */
15346 {
15351 }
15353 /* If divisor is a power of two, simplify this to bit manipulation. */
15355 {
15357 {
15371 }
15372 else
15373 {
15374 tree t;
15380 }
15381 }
15382 else
15383 {
15388 }
15391 }
15393 /* Likewise, but round down. */
15395 tree
15397 {
15404 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15405 have to do anything. Only do this when we are not given a const,
15406 because in that case, this check is more expensive than just
15407 doing it. */
15409 {
15414 }
15416 /* If divisor is a power of two, simplify this to bit manipulation. */
15418 {
15419 tree t;
15423 }
15424 else
15425 {
15430 }
15433 }
15435 /* Returns the pointer to the base of the object addressed by EXP and
15436 extracts the information about the offset of the access, storing it
15437 to PBITPOS and POFFSET. */
15439 static tree
15442 {
15443 tree core;
15444 machine_mode mode;
15446 poly_int64 bitsize;
15450 {
15455 }
15457 {
15463 {
15464 poly_offset_int tem
15470 }
15471 }
15472 else
15473 {
15477 }
15480 }
15482 /* Returns true if addresses of E1 and E2 differ by a constant, false
15483 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15485 bool
15487 {
15502 {
15512 }
15514 {
15515 /* If only one of the offsets is non-constant, the difference cannot
15516 be a constant. */
15518 }
15519 else
15524 }
15526 /* Return OFF converted to a pointer offset type suitable as offset for
15527 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
15528 tree
15530 {
15534 }
15536 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15537 tree
15539 {
15542 }
15544 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15545 tree
15547 {
15550 }
15552 /* Return a pointer to a NUL-terminated string containing the sequence
15553 of bytes corresponding to the representation of the object referred to
15554 by SRC (or a subsequence of such bytes within it if SRC is a reference
15555 to an initialized constant array plus some constant offset).
15556 Set *STRSIZE the number of bytes in the constant sequence including
15557 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
15558 where A is the array that stores the constant sequence that SRC points
15559 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
15560 need not point to a string or even an array of characters but may point
15561 to an object of any type. */
15565 {
15566 /* The offset into the array A storing the string, and A's byte size. */
15567 tree offset_node;
15568 tree mem_size;
15575 else
15582 {
15585 else
15587 }
15592 /* ARRAY_SIZE is the byte size of the array the constant sequence
15593 is stored in and equal to sizeof A. INIT_BYTES is the number
15594 of bytes in the constant sequence used to initialize the array,
15595 including any embedded NULs as well as the terminating NUL (for
15596 strings), but not including any trailing zeros/NULs past
15597 the terminating one appended implicitly to a string literal to
15598 zero out the remainder of the array it's stored in. For example,
15599 given:
15600 const char a[7] = "abc\0d";
15601 n = strlen (a + 1);
15602 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
15603 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
15604 is equal to strlen (A) + 1. */
15609 /* Ideally this would turn into a gcc_checking_assert over time. */
15617 {
15618 /* Compute and store the number of characters from the beginning
15619 of the substring at OFFSET to the end, including the terminating
15620 nul. Offsets past the initial length refer to null strings. */
15623 else
15625 }
15626 else
15627 {
15629 /* Support only properly NUL-terminated single byte strings. */
15634 }
15637 }
15639 /* Return a pointer to a NUL-terminated string corresponding to
15640 the expression STR referencing a constant string, possibly
15641 involving a constant offset. Return null if STR either doesn't
15642 reference a constant string or if it involves a nonconstant
15643 offset. */
15647 {
15649 }
15651 /* Given a tree T, compute which bits in T may be nonzero. */
15653 wide_int
15655 {
15657 {
15675 CASE_CONVERT:
15681 {
15686 }
15690 {
15698 }
15702 {
15710 }
15714 }
15717 }
15719 #if CHECKING_P
15723 /* Helper functions for writing tests of folding trees. */
15725 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
15727 static void
15729 tree constant)
15730 {
15732 }
15734 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
15735 wrapping WRAPPED_EXPR. */
15737 static void
15739 tree wrapped_expr)
15740 {
15745 }
15747 /* Verify that various arithmetic binary operations are folded
15748 correctly. */
15750 static void
15752 {
15758 /* Addition. */
15759 /* 1 <-- (0 + 1) */
15761 one);
15763 one);
15765 /* (nonlvalue)x <-- (x + 0) */
15767 x);
15769 /* Subtraction. */
15770 /* 0 <-- (x - x) */
15772 zero);
15774 x);
15776 /* Multiplication. */
15777 /* 0 <-- (x * 0) */
15779 zero);
15781 /* (nonlvalue)x <-- (x * 1) */
15783 x);
15784 }
15786 /* Verify that various binary operations on vectors are folded
15787 correctly. */
15789 static void
15791 {
15798 /* Verify equality tests that return a scalar boolean result. */
15811 }
15813 /* Verify folding of VEC_DUPLICATE_EXPRs. */
15815 static void
15817 {
15820 /* This will be 1 if VEC_MODE isn't a vector mode. */
15827 }
15829 /* Run all of the selftests within this file. */
15831 void
15833 {
15837 }