| blob | ebd32bb2e04584c9e0d9624e01494c7c71ec285c |
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. */
3327 /* Virtual table call. */
3329 {
3343 }
3347 }
3351 {
3353 /* Be sure we pass right ADDRESS_OF flag. */
3370 /* The multiplcation operands are commutative. */
3371 /* FALLTHRU */
3379 /* Otherwise take into account this is a commutative operation. */
3392 /* BIT_INSERT_EXPR has an implict operand as the type precision
3393 of op1. Need to check to make sure they are the same. */
3399 /* FALLTHRU */
3425 }
3429 {
3433 /* If not both CALL_EXPRs are either internal or normal function
3434 functions, then they are not equal. */
3437 {
3438 /* If the CALL_EXPRs call different internal functions, then they
3439 are not equal. */
3442 }
3443 else
3444 {
3445 /* If the CALL_EXPRs call different functions, then they are not
3446 equal. */
3448 flags))
3450 }
3452 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3453 {
3457 else
3461 }
3463 /* Now see if all the arguments are the same. */
3464 {
3475 /* If we get here and both argument lists are exhausted
3476 then the CALL_EXPRs are equal. */
3478 }
3481 }
3484 /* Consider __builtin_sqrt equal to sqrt. */
3493 {
3497 /* In GIMPLE constructors are used only to build vectors from
3498 elements. Individual elements in the constructor must be
3499 indexed in increasing order and form an initial sequence.
3501 We make no effort to compare constructors in generic.
3502 (see sem_variable::equals in ipa-icf which can do so for
3503 constants). */
3508 /* Be sure that vectors constructed have the same representation.
3509 We only tested element precision and modes to match.
3510 Vectors may be BLKmode and thus also check that the number of
3511 parts match. */
3524 {
3529 /* In GIMPLE the indexes can be either NULL or matching i.
3530 Double check this so we won't get false
3531 positives for GENERIC. */
3539 }
3541 }
3544 {
3545 /* Compare the STATEMENT_LISTs. */
3551 {
3552 /* The lists don't have the same number of statements. */
3558 flags & (OEP_LEXICOGRAPHIC
3561 }
3562 }
3567 {
3578 }
3582 }
3584 #undef OP_SAME
3585 #undef OP_SAME_WITH_NULL
3586 }
3588 /* Generate a hash value for an expression. This can be used iteratively
3589 by passing a previous result as the HSTATE argument. */
3591 void
3594 {
3600 {
3603 }
3613 {
3614 /* Alas, constants aren't shared, so we can't rely on pointer
3615 identity. */
3625 {
3629 else
3633 }
3635 {
3639 }
3649 {
3656 }
3658 /* We can just compare by pointer. */
3662 /* The node itself doesn't matter. */
3666 /* Ignore. */
3669 /* A list of expressions, for a CALL_EXPR or as the elements of a
3670 VECTOR_CST. */
3675 {
3681 {
3682 /* In GIMPLE the indexes can be either NULL or matching i. */
3687 }
3689 }
3691 {
3692 tree_stmt_iterator i;
3697 }
3706 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3707 Otherwise nodes that compare equal according to operand_equal_p might
3708 get different hash codes. However, don't do this for machine specific
3709 or front end builtins, since the function code is overloaded in those
3710 cases. */
3713 {
3716 }
3717 /* FALL THROUGH */
3720 {
3724 }
3728 {
3729 /* DECL's have a unique ID */
3731 }
3733 {
3734 /* For comparisons that can be swapped, use the lower
3735 tree code. */
3742 }
3744 {
3745 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3746 operand_equal_p. */
3750 /* Don't hash the type, that can lead to having nodes which
3751 compare equal according to operand_equal_p, but which
3752 have different hash codes. Make sure to include signedness
3753 in the hash computation. */
3756 }
3757 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3765 /* Don't ICE on FE specific trees, or their arguments etc.
3766 during operand_equal_p hash verification. */
3769 else
3770 {
3776 {
3803 {
3804 /* The multiplication operands are commutative. */
3811 }
3819 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3820 Usually different TARGET_EXPRs just should use
3821 different temporaries in their slots. */
3825 /* Virtual table call. */
3833 }
3835 /* Don't hash the type, that can lead to having nodes which
3836 compare equal according to operand_equal_p, but which
3837 have different hash codes. */
3839 {
3840 /* Make sure to include signness in the hash computation. */
3843 }
3846 {
3847 /* It's a commutative expression. We want to hash it the same
3848 however it appears. We do this by first hashing both operands
3849 and then rehashing based on the order of their independent
3850 hashes. */
3855 }
3856 else
3860 }
3862 }
3863 }
3865 bool
3868 {
3869 /* When checking, verify at the outermost operand_equal_p call that
3870 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
3871 hash value. */
3873 {
3875 {
3877 {
3884 }
3886 }
3887 else
3891 }
3894 }
3899 /* Conveinece wrapper around operand_compare class because usually we do
3900 not need to play with the valueizer. */
3902 bool
3904 {
3906 }
3908 namespace inchash
3909 {
3911 /* Generate a hash value for an expression. This can be used iteratively
3912 by passing a previous result as the HSTATE argument.
3914 This function is intended to produce the same hash for expressions which
3915 would compare equal using operand_equal_p. */
3916 void
3918 {
3920 }
3922 }
3923 \f
3924 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3925 with a different signedness or a narrower precision. */
3927 static bool
3929 {
3937 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3938 and see if the inner values are the same. This removes any
3939 signedness comparison, which doesn't matter here. */
3947 /* Discard a single widening conversion from ARG1 and see if the inner
3948 value is the same as ARG0. */
3957 }
3958 \f
3959 /* See if ARG is an expression that is either a comparison or is performing
3960 arithmetic on comparisons. The comparisons must only be comparing
3961 two different values, which will be stored in *CVAL1 and *CVAL2; if
3962 they are nonzero it means that some operands have already been found.
3963 No variables may be used anywhere else in the expression except in the
3964 comparisons.
3966 If this is true, return 1. Otherwise, return zero. */
3968 static bool
3970 {
3974 /* We can handle some of the tcc_expression cases here. */
3983 {
4002 /* First see if we can handle the first operand, then the second. For
4003 the second operand, we know *CVAL1 can't be zero. It must be that
4004 one side of the comparison is each of the values; test for the
4005 case where this isn't true by failing if the two operands
4006 are the same. */
4015 ;
4019 ;
4020 else
4024 ;
4028 ;
4029 else
4036 }
4037 }
4038 \f
4039 /* ARG is a tree that is known to contain just arithmetic operations and
4040 comparisons. Evaluate the operations in the tree substituting NEW0 for
4041 any occurrence of OLD0 as an operand of a comparison and likewise for
4042 NEW1 and OLD1. */
4044 static tree
4047 {
4052 /* We can handle some of the tcc_expression cases here. */
4060 {
4075 {
4094 }
4095 /* Fall through - ??? */
4098 {
4102 /* We need to check both for exact equality and tree equality. The
4103 former will be true if the operand has a side-effect. In that
4104 case, we know the operand occurred exactly once. */
4117 }
4121 }
4122 }
4123 \f
4124 /* Return a tree for the case when the result of an expression is RESULT
4125 converted to TYPE and OMITTED was previously an operand of the expression
4126 but is now not needed (e.g., we folded OMITTED * 0).
4128 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4129 the conversion of RESULT to TYPE. */
4131 tree
4133 {
4136 /* If the resulting operand is an empty statement, just return the omitted
4137 statement casted to void. */
4147 }
4149 /* Return a tree for the case when the result of an expression is RESULT
4150 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4151 of the expression but are now not needed.
4153 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4154 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4155 evaluated before OMITTED2. Otherwise, if neither has side effects,
4156 just do the conversion of RESULT to TYPE. */
4158 tree
4161 {
4170 }
4172 \f
4173 /* Return a simplified tree node for the truth-negation of ARG. This
4174 never alters ARG itself. We assume that ARG is an operation that
4175 returns a truth value (0 or 1).
4177 FIXME: one would think we would fold the result, but it causes
4178 problems with the dominator optimizer. */
4180 static tree
4182 {
4187 /* If this is a comparison, we can simply invert it, except for
4188 floating-point non-equality comparisons, in which case we just
4189 enclose a TRUTH_NOT_EXPR around what we have. */
4192 {
4195 && flag_trapping_math
4209 }
4212 {
4231 /* Here we can invert either operand. We invert the first operand
4232 unless the second operand is a TRUTH_NOT_EXPR in which case our
4233 result is the XOR of the first operand with the inside of the
4234 negation of the second operand. */
4239 else
4262 {
4269 /* A COND_EXPR may have a throw as one operand, which
4270 then has void type. Just leave void operands
4271 as they are. */
4277 }
4289 CASE_CONVERT:
4293 /* fall through */
4315 }
4316 }
4318 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4319 assume that ARG is an operation that returns a truth value (0 or 1
4320 for scalars, 0 or -1 for vectors). Return the folded expression if
4321 folding is successful. Otherwise, return NULL_TREE. */
4323 static tree
4325 {
4328 ? BIT_NOT_EXPR
4331 }
4333 /* Return a simplified tree node for the truth-negation of ARG. This
4334 never alters ARG itself. We assume that ARG is an operation that
4335 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4337 tree
4339 {
4345 ? BIT_NOT_EXPR
4348 }
4349 \f
4350 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4351 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4352 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4353 is the original memory reference used to preserve the alias set of
4354 the access. */
4356 static tree
4360 {
4363 /* Attempt not to lose the access path if possible. */
4365 {
4367 machine_mode nmode;
4369 tree noffset;
4377 && !reversep
4378 && !nreversep
4380 {
4383 }
4384 }
4393 {
4400 }
4415 }
4417 /* Optimize a bit-field compare.
4419 There are two cases: First is a compare against a constant and the
4420 second is a comparison of two items where the fields are at the same
4421 bit position relative to the start of a chunk (byte, halfword, word)
4422 large enough to contain it. In these cases we can avoid the shift
4423 implicit in bitfield extractions.
4425 For constants, we emit a compare of the shifted constant with the
4426 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4427 compared. For two fields at the same position, we do the ANDs with the
4428 similar mask and compare the result of the ANDs.
4430 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4431 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4432 are the left and right operands of the comparison, respectively.
4434 If the optimization described above can be done, we return the resulting
4435 tree. Otherwise we return zero. */
4437 static tree
4440 {
4444 tree unsigned_type;
4447 scalar_int_mode nmode;
4452 tree mask;
4453 tree offset;
4455 /* Get all the information about the extractions being done. If the bit size
4456 is the same as the size of the underlying object, we aren't doing an
4457 extraction at all and so can do nothing. We also don't want to
4458 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4459 then will no longer be able to replace it. */
4474 else
4475 {
4476 /* If this is not a constant, we can only do something if bit positions,
4477 sizes, signedness and storage order are the same. */
4478 rinner
4491 }
4493 /* Honor the C++ memory model and mimic what RTL expansion does. */
4497 {
4501 }
4503 /* See if we can find a mode to refer to this field. We should be able to,
4504 but fail if we can't. */
4512 /* Set signed and unsigned types of the precision of this mode for the
4513 shifts below. */
4516 /* Compute the bit position and size for the new reference and our offset
4517 within it. If the new reference is the same size as the original, we
4518 won't optimize anything, so return zero. */
4528 /* Make the mask to be used against the extracted field. */
4535 {
4539 /* If not comparing with constant, just rework the comparison
4540 and return. */
4548 }
4550 /* Otherwise, we are handling the constant case. See if the constant is too
4551 big for the field. Warn and return a tree for 0 (false) if so. We do
4552 this not only for its own sake, but to avoid having to test for this
4553 error case below. If we didn't, we might generate wrong code.
4555 For unsigned fields, the constant shifted right by the field length should
4556 be all zero. For signed fields, the high-order bits should agree with
4557 the sign bit. */
4560 {
4562 {
4566 }
4567 }
4568 else
4569 {
4572 {
4576 }
4577 }
4582 /* Single-bit compares should always be against zero. */
4584 {
4587 }
4589 /* Make a new bitfield reference, shift the constant over the
4590 appropriate number of bits and mask it with the computed mask
4591 (in case this was a signed field). If we changed it, make a new one. */
4599 mask);
4604 }
4605 \f
4606 /* Subroutine for fold_truth_andor_1: decode a field reference.
4608 If EXP is a comparison reference, we return the innermost reference.
4610 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4611 set to the starting bit number.
4613 If the innermost field can be completely contained in a mode-sized
4614 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4616 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4617 otherwise it is not changed.
4619 *PUNSIGNEDP is set to the signedness of the field.
4621 *PREVERSEP is set to the storage order of the field.
4623 *PMASK is set to the mask used. This is either contained in a
4624 BIT_AND_EXPR or derived from the width of the field.
4626 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4628 Return 0 if this is not a component reference or is one that we can't
4629 do anything with. */
4631 static tree
4636 {
4641 tree unsigned_type;
4644 /* All the optimizations using this function assume integer fields.
4645 There are problems with FP fields since the type_for_size call
4646 below can fail for, e.g., XFmode. */
4650 /* We are interested in the bare arrangement of bits, so strip everything
4651 that doesn't affect the machine mode. However, record the type of the
4652 outermost expression if it may matter below. */
4659 {
4665 }
4676 /* Reject out-of-bound accesses (PR79731). */
4688 /* If the number of bits in the reference is the same as the bitsize of
4689 the outer type, then the outer type gives the signedness. Otherwise
4690 (in case of a small bitfield) the signedness is unchanged. */
4694 /* Compute the mask to access the bitfield. */
4702 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4710 }
4712 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4713 bit positions and MASK is SIGNED. */
4715 static bool
4717 {
4721 /* If this function returns true when the type of the mask is
4722 UNSIGNED, then there will be errors. In particular see
4723 gcc.c-torture/execute/990326-1.c. There does not appear to be
4724 any documentation paper trail as to why this is so. But the pre
4725 wide-int worked with that restriction and it has been preserved
4726 here. */
4731 }
4733 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4734 represents the sign bit of EXP's type. If EXP represents a sign
4735 or zero extension, also test VAL against the unextended type.
4736 The return value is the (sub)expression whose sign bit is VAL,
4737 or NULL_TREE otherwise. */
4739 tree
4741 {
4743 tree t;
4745 /* Tree EXP must have an integral type. */
4750 /* Tree VAL must be an integer constant. */
4759 /* Handle extension from a narrower type. */
4765 }
4767 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4768 to be evaluated unconditionally. */
4770 static bool
4772 {
4773 /* Strip any conversions that don't change the machine mode. */
4782 /* Don't regard global variables as simple. They may be
4783 allocated in ways unknown to the compiler (shared memory,
4784 #pragma weak, etc). */
4787 /* Weakrefs are not safe to be read, since they can be NULL.
4788 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4789 have DECL_WEAK flag set. */
4791 /* Loading a static variable is unduly expensive, but global
4792 registers aren't expensive. */
4794 }
4796 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4797 to be evaluated unconditionally.
4798 I addition to simple_operand_p, we assume that comparisons, conversions,
4799 and logic-not operations are simple, if their operands are simple, too. */
4801 static bool
4803 {
4822 }
4824 \f
4825 /* The following functions are subroutines to fold_range_test and allow it to
4826 try to change a logical combination of comparisons into a range test.
4828 For example, both
4829 X == 2 || X == 3 || X == 4 || X == 5
4830 and
4831 X >= 2 && X <= 5
4832 are converted to
4833 (unsigned) (X - 2) <= 3
4835 We describe each set of comparisons as being either inside or outside
4836 a range, using a variable named like IN_P, and then describe the
4837 range with a lower and upper bound. If one of the bounds is omitted,
4838 it represents either the highest or lowest value of the type.
4840 In the comments below, we represent a range by two numbers in brackets
4841 preceded by a "+" to designate being inside that range, or a "-" to
4842 designate being outside that range, so the condition can be inverted by
4843 flipping the prefix. An omitted bound is represented by a "-". For
4844 example, "- [-, 10]" means being outside the range starting at the lowest
4845 possible value and ending at 10, in other words, being greater than 10.
4846 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4847 always false.
4849 We set up things so that the missing bounds are handled in a consistent
4850 manner so neither a missing bound nor "true" and "false" need to be
4851 handled using a special case. */
4853 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4854 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4855 and UPPER1_P are nonzero if the respective argument is an upper bound
4856 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4857 must be specified for a comparison. ARG1 will be converted to ARG0's
4858 type if both are specified. */
4860 static tree
4863 {
4864 tree tem;
4868 /* If neither arg represents infinity, do the normal operation.
4869 Else, if not a comparison, return infinity. Else handle the special
4870 comparison rules. Note that most of the cases below won't occur, but
4871 are handled for consistency. */
4874 {
4879 }
4884 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4885 for neither. In real maths, we cannot assume open ended ranges are
4886 the same. But, this is computer arithmetic, where numbers are finite.
4887 We can therefore make the transformation of any unbounded range with
4888 the value Z, Z being greater than any representable number. This permits
4889 us to treat unbounded ranges as equal. */
4893 {
4914 }
4917 }
4918 \f
4919 /* Helper routine for make_range. Perform one step for it, return
4920 new expression if the loop should continue or NULL_TREE if it should
4921 stop. */
4923 tree
4927 {
4933 {
4935 /* We can only do something if the range is testing for zero. */
4944 /* We can only do something if the range is testing for zero
4945 and if the second operand is an integer constant. Note that
4946 saying something is "in" the range we make is done by
4947 complementing IN_P since it will set in the initial case of
4948 being not equal to zero; "out" is leaving it alone. */
4955 {
4976 }
4978 /* If this is an unsigned comparison, we also know that EXP is
4979 greater than or equal to zero. We base the range tests we make
4980 on that fact, so we record it here so we can parse existing
4981 range tests. We test arg0_type since often the return type
4982 of, e.g. EQ_EXPR, is boolean. */
4984 {
4988 NULL_TREE))
4993 /* If the high bound is missing, but we have a nonzero low
4994 bound, reverse the range so it goes from zero to the low bound
4995 minus 1. */
4997 {
5002 }
5003 }
5011 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5012 low and high are non-NULL, then normalize will DTRT. */
5015 {
5020 }
5022 /* (-x) IN [a,b] -> x in [-b, -a] */
5034 /* ~ X -> -X - 1 */
5043 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5044 move a constant to the other side. */
5049 /* If EXP is signed, any overflow in the computation is undefined,
5050 so we don't worry about it so long as our computations on
5051 the bounds don't overflow. For unsigned, overflow is defined
5052 and this is exactly the right thing. */
5064 normalize:
5065 /* Check for an unsigned range which has wrapped around the maximum
5066 value thus making n_high < n_low, and normalize it. */
5068 {
5074 /* If the range is of the form +/- [ x+1, x ], we won't
5075 be able to normalize it. But then, it represents the
5076 whole range or the empty set, so make it
5077 +/- [ -, - ]. */
5081 else
5083 }
5084 else
5092 CASE_CONVERT:
5110 /* If we're converting arg0 from an unsigned type, to exp,
5111 a signed type, we will be doing the comparison as unsigned.
5112 The tests above have already verified that LOW and HIGH
5113 are both positive.
5115 So we have to ensure that we will handle large unsigned
5116 values the same way that the current signed bounds treat
5117 negative values. */
5120 {
5121 tree high_positive;
5122 tree equiv_type;
5123 /* For fixed-point modes, we need to pass the saturating flag
5124 as the 2nd parameter. */
5126 equiv_type
5129 else
5130 equiv_type
5133 /* A range without an upper bound is, naturally, unbounded.
5134 Since convert would have cropped a very large value, use
5135 the max value for the destination type. */
5136 high_positive
5143 high_positive),
5146 /* If the low bound is specified, "and" the range with the
5147 range for which the original unsigned value will be
5148 positive. */
5150 {
5153 integer_zero_node),
5154 high_positive))
5158 }
5159 else
5160 {
5161 /* Otherwise, "or" the range with the range of the input
5162 that will be interpreted as negative. */
5165 integer_zero_node),
5166 high_positive))
5170 }
5171 }
5180 }
5181 }
5183 /* Given EXP, a logical expression, set the range it is testing into
5184 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5185 actually being tested. *PLOW and *PHIGH will be made of the same
5186 type as the returned expression. If EXP is not a comparison, we
5187 will most likely not be returning a useful value and range. Set
5188 *STRICT_OVERFLOW_P to true if the return value is only valid
5189 because signed overflow is undefined; otherwise, do not change
5190 *STRICT_OVERFLOW_P. */
5192 tree
5195 {
5203 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5204 and see if we can refine the range. Some of the cases below may not
5205 happen, but it doesn't seem worth worrying about this. We "continue"
5206 the outer loop when we've changed something; otherwise we "break"
5207 the switch, which will "break" the while. */
5213 {
5219 {
5227 }
5236 }
5238 /* If EXP is a constant, we can evaluate whether this is true or false. */
5240 {
5247 }
5251 }
5253 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5254 a bitwise check i.e. when
5255 LOW == 0xXX...X00...0
5256 HIGH == 0xXX...X11...1
5257 Return corresponding mask in MASK and stem in VALUE. */
5259 static bool
5262 {
5285 }
5286 \f
5287 /* Helper routine for build_range_check and match.pd. Return the type to
5288 perform the check or NULL if it shouldn't be optimized. */
5290 tree
5292 {
5293 /* First make sure that arithmetics in this type is valid, then make sure
5294 that it wraps around. */
5299 {
5302 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5303 for the type in question, as we rely on this here. */
5313 else
5315 }
5319 }
5321 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5322 type, TYPE, return an expression to test if EXP is in (or out of, depending
5323 on IN_P) the range. Return 0 if the test couldn't be created. */
5325 tree
5328 {
5331 /* Disable this optimization for function pointer expressions
5332 on targets that require function pointer canonicalization. */
5339 {
5345 }
5367 value);
5370 {
5372 {
5376 }
5378 }
5380 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5382 {
5386 {
5388 {
5391 etype
5393 else
5396 }
5399 }
5400 }
5402 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5403 This requires wrap-around arithmetics for the type of the expression. */
5420 }
5421 \f
5422 /* Return the predecessor of VAL in its type, handling the infinite case. */
5424 static tree
5426 {
5432 else
5435 }
5437 /* Return the successor of VAL in its type, handling the infinite case. */
5439 static tree
5441 {
5447 else
5450 }
5452 /* Given two ranges, see if we can merge them into one. Return 1 if we
5453 can, 0 if we can't. Set the output range into the specified parameters. */
5455 bool
5458 {
5462 tree tem;
5472 /* Make range 0 be the range that starts first, or ends last if they
5473 start at the same value. Swap them if it isn't. */
5476 || (lowequal
5479 {
5483 }
5485 /* If the second range is != high1 where high1 is the type maximum of
5486 the type, try first merging with < high1 range. */
5488 && high1
5495 {
5500 /* Similarly for the second range != low1 where low1 is the type minimum
5501 of the type, try first merging with > low1 range. */
5506 }
5508 /* Now flag two cases, whether the ranges are disjoint or whether the
5509 second range is totally subsumed in the first. Note that the tests
5510 below are simplified by the ones above. */
5516 /* We now have four cases, depending on whether we are including or
5517 excluding the two ranges. */
5519 {
5520 /* If they don't overlap, the result is false. If the second range
5521 is a subset it is the result. Otherwise, the range is from the start
5522 of the second to the end of the first. */
5527 else
5529 }
5532 {
5533 /* If they don't overlap, the result is the first range. If they are
5534 equal, the result is false. If the second range is a subset of the
5535 first, and the ranges begin at the same place, we go from just after
5536 the end of the second range to the end of the first. If the second
5537 range is not a subset of the first, or if it is a subset and both
5538 ranges end at the same place, the range starts at the start of the
5539 first range and ends just before the second range.
5540 Otherwise, we can't describe this as a single range. */
5546 {
5551 {
5552 /* We are in the weird situation where high0 > high1 but
5553 high1 has no successor. Punt. */
5555 }
5556 }
5558 {
5563 {
5564 /* low0 < low1 but low1 has no predecessor. Punt. */
5566 }
5567 }
5568 else
5570 }
5573 {
5574 /* If they don't overlap, the result is the second range. If the second
5575 is a subset of the first, the result is false. Otherwise,
5576 the range starts just after the first range and ends at the
5577 end of the second. */
5582 else
5583 {
5588 {
5589 /* high1 > high0 but high0 has no successor. Punt. */
5591 }
5592 }
5593 }
5595 else
5596 {
5597 /* The case where we are excluding both ranges. Here the complex case
5598 is if they don't overlap. In that case, the only time we have a
5599 range is if they are adjacent. If the second is a subset of the
5600 first, the result is the first. Otherwise, the range to exclude
5601 starts at the beginning of the first range and ends at the end of the
5602 second. */
5604 {
5609 else
5610 {
5611 /* Canonicalize - [min, x] into - [-, x]. */
5614 {
5617 GET_MODE_BITSIZE
5620 /* FALLTHROUGH */
5633 }
5635 /* Canonicalize - [x, max] into - [x, -]. */
5638 {
5641 GET_MODE_BITSIZE
5644 /* FALLTHROUGH */
5660 }
5662 /* The ranges might be also adjacent between the maximum and
5663 minimum values of the given type. For
5664 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5665 return + [x + 1, y - 1]. */
5667 {
5674 }
5675 else
5677 }
5678 }
5681 else
5683 }
5687 }
5688 \f
5690 /* Subroutine of fold, looking inside expressions of the form
5691 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5692 of the COND_EXPR. This function is being used also to optimize
5693 A op B ? C : A, by reversing the comparison first.
5695 Return a folded expression whose code is not a COND_EXPR
5696 anymore, or NULL_TREE if no folding opportunity is found. */
5698 static tree
5701 {
5706 tree tem;
5711 /* If we have A op 0 ? A : -A, consider applying the following
5712 transformations:
5714 A == 0? A : -A same as -A
5715 A != 0? A : -A same as A
5716 A >= 0? A : -A same as abs (A)
5717 A > 0? A : -A same as abs (A)
5718 A <= 0? A : -A same as -abs (A)
5719 A < 0? A : -A same as -abs (A)
5721 None of these transformations work for modes with signed
5722 zeros. If A is +/-0, the first two transformations will
5723 change the sign of the result (from +0 to -0, or vice
5724 versa). The last four will fix the sign of the result,
5725 even though the original expressions could be positive or
5726 negative, depending on the sign of A.
5728 Note that all these transformations are correct if A is
5729 NaN, since the two alternatives (A and -A) are also NaNs. */
5736 /* In the case that A is of the form X-Y, '-A' (arg2) may
5737 have already been folded to Y-X, check for that. */
5745 {
5757 /* Fall through. */
5768 /* FALLTHRU */
5775 {
5776 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5777 is not, invokes UB both in abs and in the negation of it.
5778 So, use ABSU_EXPR instead. */
5783 }
5784 else
5785 {
5788 }
5792 }
5794 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5795 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5796 both transformations are correct when A is NaN: A != 0
5797 is then true, and A == 0 is false. */
5801 {
5806 }
5808 /* Try some transformations of A op B ? A : B.
5810 A == B? A : B same as B
5811 A != B? A : B same as A
5812 A >= B? A : B same as max (A, B)
5813 A > B? A : B same as max (B, A)
5814 A <= B? A : B same as min (A, B)
5815 A < B? A : B same as min (B, A)
5817 As above, these transformations don't work in the presence
5818 of signed zeros. For example, if A and B are zeros of
5819 opposite sign, the first two transformations will change
5820 the sign of the result. In the last four, the original
5821 expressions give different results for (A=+0, B=-0) and
5822 (A=-0, B=+0), but the transformed expressions do not.
5824 The first two transformations are correct if either A or B
5825 is a NaN. In the first transformation, the condition will
5826 be false, and B will indeed be chosen. In the case of the
5827 second transformation, the condition A != B will be true,
5828 and A will be chosen.
5830 The conversions to max() and min() are not correct if B is
5831 a number and A is not. The conditions in the original
5832 expressions will be false, so all four give B. The min()
5833 and max() versions would give a NaN instead. */
5836 /* Avoid these transformations if the COND_EXPR may be used
5837 as an lvalue in the C++ front-end. PR c++/19199. */
5838 && (in_gimple_form
5844 {
5850 {
5859 /* In C++ a ?: expression can be an lvalue, so put the
5860 operand which will be used if they are equal first
5861 so that we can convert this back to the
5862 corresponding COND_EXPR. */
5864 {
5872 }
5879 {
5887 }
5900 }
5901 }
5904 }
5907 \f
5908 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5909 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5910 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5911 false) >= 2)
5912 #endif
5914 /* EXP is some logical combination of boolean tests. See if we can
5915 merge it into some range test. Return the new tree if so. */
5917 static tree
5920 {
5934 /* If op0 is known true or false and this is a short-circuiting
5935 operation we must not merge with op1 since that makes side-effects
5936 unconditional. So special-case this. */
5943 /* If this is an OR operation, invert both sides; we will invert
5944 again at the end. */
5948 /* If both expressions are the same, if we can merge the ranges, and we
5949 can build the range test, return it or it inverted. If one of the
5950 ranges is always true or always false, consider it to be the same
5951 expression as the other. */
5959 {
5963 }
5965 /* On machines where the branch cost is expensive, if this is a
5966 short-circuited branch and the underlying object on both sides
5967 is the same, make a non-short-circuit operation. */
5970 logical_op_non_short_circuit
5973 && !flag_sanitize_coverage
5977 {
5978 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5979 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5980 which cases we can't do this. */
5988 {
5997 {
6000 WARN_STRICT_OVERFLOW_COMPARISON);
6004 }
6005 }
6006 }
6009 }
6010 \f
6011 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6012 bit value. Arrange things so the extra bits will be set to zero if and
6013 only if C is signed-extended to its full width. If MASK is nonzero,
6014 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6016 static tree
6018 {
6021 tree temp;
6026 /* We work by getting just the sign bit into the low-order bit, then
6027 into the high-order bit, then sign-extend. We then XOR that value
6028 with C. */
6032 /* We must use a signed type in order to get an arithmetic right shift.
6033 However, we must also avoid introducing accidental overflows, so that
6034 a subsequent call to integer_zerop will work. Hence we must
6035 do the type conversion here. At this point, the constant is either
6036 zero or one, and the conversion to a signed type can never overflow.
6037 We could get an overflow if this conversion is done anywhere else. */
6046 /* If necessary, convert the type back to match the type of C. */
6051 }
6052 \f
6053 /* For an expression that has the form
6054 (A && B) || ~B
6055 or
6056 (A || B) && ~B,
6057 we can drop one of the inner expressions and simplify to
6058 A || ~B
6059 or
6060 A && ~B
6061 LOC is the location of the resulting expression. OP is the inner
6062 logical operation; the left-hand side in the examples above, while CMPOP
6063 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6064 removing a condition that guards another, as in
6065 (A != NULL && A->...) || A == NULL
6066 which we must not transform. If RHS_ONLY is true, only eliminate the
6067 right-most operand of the inner logical operation. */
6069 static tree
6072 {
6090 {
6093 {
6096 }
6097 }
6099 {
6102 {
6105 }
6106 }
6121 }
6123 /* Find ways of folding logical expressions of LHS and RHS:
6124 Try to merge two comparisons to the same innermost item.
6125 Look for range tests like "ch >= '0' && ch <= '9'".
6126 Look for combinations of simple terms on machines with expensive branches
6127 and evaluate the RHS unconditionally.
6129 For example, if we have p->a == 2 && p->b == 4 and we can make an
6130 object large enough to span both A and B, we can do this with a comparison
6131 against the object ANDed with the a mask.
6133 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6134 operations to do this with one comparison.
6136 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6137 function and the one above.
6139 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6140 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6142 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6143 two operands.
6145 We return the simplified tree or 0 if no optimization is possible. */
6147 static tree
6150 {
6151 /* If this is the "or" of two comparisons, we can do something if
6152 the comparisons are NE_EXPR. If this is the "and", we can do something
6153 if the comparisons are EQ_EXPR. I.e.,
6154 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6156 WANTED_CODE is this operation code. For single bit fields, we can
6157 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6158 comparison for one-bit fields. */
6179 /* Start by getting the comparison codes. Fail if anything is volatile.
6180 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6181 it were surrounded with a NE_EXPR. */
6190 {
6194 }
6197 {
6201 }
6212 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6215 {
6218 {
6223 }
6226 {
6232 }
6233 }
6238 /* If the RHS can be evaluated unconditionally and its operands are
6239 simple, it wins to evaluate the RHS unconditionally on machines
6240 with expensive branches. In this case, this isn't a comparison
6241 that can be merged. */
6248 {
6249 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6260 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6270 }
6272 /* See if the comparisons can be merged. Then get all the parameters for
6273 each side. */
6298 /* It must be true that the inner operation on the lhs of each
6299 comparison must be the same if we are to be able to do anything.
6300 Then see if we have constants. If not, the same must be true for
6301 the rhs's. */
6310 {
6313 }
6318 else
6321 /* If either comparison code is not correct for our logical operation,
6322 fail. However, we can convert a one-bit comparison against zero into
6323 the opposite comparison against that bit being set in the field. */
6327 {
6329 {
6330 /* Make the left operand unsigned, since we are only interested
6331 in the value of one bit. Otherwise we are doing the wrong
6332 thing below. */
6335 }
6336 else
6338 }
6340 /* This is analogous to the code for l_const above. */
6342 {
6344 {
6347 }
6348 else
6350 }
6352 /* See if we can find a mode that contains both fields being compared on
6353 the left. If we can't, fail. Otherwise, update all constants and masks
6354 to be relative to a field of that size. */
6368 {
6371 }
6379 {
6386 {
6390 }
6391 }
6393 {
6400 {
6404 }
6405 }
6407 /* If the right sides are not constant, do the same for it. Also,
6408 disallow this optimization if a size, signedness or storage order
6409 mismatch occurs between the left and right sides. */
6411 {
6415 /* Make sure the two fields on the right
6416 correspond to the left without being swapped. */
6433 {
6436 }
6445 /* Make a mask that corresponds to both fields being compared.
6446 Do this for both items being compared. If the operands are the
6447 same size and the bits being compared are in the same position
6448 then we can do this by masking both and comparing the masked
6449 results. */
6456 {
6470 }
6472 /* There is still another way we can do something: If both pairs of
6473 fields being compared are adjacent, we may be able to make a wider
6474 field containing them both.
6476 Note that we still must mask the lhs/rhs expressions. Furthermore,
6477 the mask must be shifted to account for the shift done by
6478 make_bit_field_ref. */
6487 {
6488 tree type;
6504 /* Convert to the smaller type before masking out unwanted bits. */
6507 {
6509 {
6513 }
6515 {
6519 }
6520 }
6529 }
6532 }
6534 /* Handle the case of comparisons with constants. If there is something in
6535 common between the masks, those bits of the constants must be the same.
6536 If not, the condition is always false. Test for this to avoid generating
6537 incorrect code below. */
6542 {
6544 {
6547 }
6548 else
6549 {
6552 }
6553 }
6558 /* Construct the expression we will return. First get the component
6559 reference we will make. Unless the mask is all ones the width of
6560 that field, perform the mask operation. Then compare with the
6561 merged constant. */
6572 }
6573 \f
6574 /* T is an integer expression that is being multiplied, divided, or taken a
6575 modulus (CODE says which and what kind of divide or modulus) by a
6576 constant C. See if we can eliminate that operation by folding it with
6577 other operations already in T. WIDE_TYPE, if non-null, is a type that
6578 should be used for the computation if wider than our type.
6580 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6581 (X * 2) + (Y * 4). We must, however, be assured that either the original
6582 expression would not overflow or that overflow is undefined for the type
6583 in the language in question.
6585 If we return a non-null expression, it is an equivalent form of the
6586 original computation, but need not be in the original type.
6588 We set *STRICT_OVERFLOW_P to true if the return values depends on
6589 signed overflow being undefined. Otherwise we do not change
6590 *STRICT_OVERFLOW_P. */
6592 static tree
6595 {
6596 /* To avoid exponential search depth, refuse to allow recursion past
6597 three levels. Beyond that (1) it's highly unlikely that we'll find
6598 something interesting and (2) we've probably processed it before
6599 when we built the inner expression. */
6602 tree ret;
6607 depth++;
6609 depth--;
6612 }
6614 static tree
6617 {
6629 /* Don't deal with constants of zero here; they confuse the code below. */
6639 /* Note that we need not handle conditional operations here since fold
6640 already handles those cases. So just do arithmetic here. */
6642 {
6644 /* For a constant, we can always simplify if we are a multiply
6645 or (for divide and modulus) if it is a multiple of our constant. */
6649 {
6652 /* If the multiplication overflowed, we lost information on it.
6653 See PR68142 and PR69845. */
6657 }
6661 /* If op0 is an expression ... */
6667 /* ... and has wrapping overflow, and its type is smaller
6668 than ctype, then we cannot pass through as widening. */
6673 /* ... or this is a truncation (t is narrower than op0),
6674 then we cannot pass through this narrowing. */
6677 /* ... or signedness changes for division or modulus,
6678 then we cannot pass through this conversion. */
6682 /* ... or has undefined overflow while the converted to
6683 type has not, we cannot do the operation in the inner type
6684 as that would introduce undefined overflow. */
6690 /* Pass the constant down and see if we can make a simplification. If
6691 we can, replace this expression with the inner simplification for
6692 possible later conversion to our or some other type. */
6703 /* If widening the type changes it from signed to unsigned, then we
6704 must avoid building ABS_EXPR itself as unsigned. */
6706 {
6710 {
6713 }
6715 }
6716 /* If the constant is negative, we cannot simplify this. */
6719 /* FALLTHROUGH */
6721 /* For division and modulus, type can't be unsigned, as e.g.
6722 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6723 For signed types, even with wrapping overflow, this is fine. */
6732 /* If widening the type changes the signedness, then we can't perform
6733 this optimization as that changes the result. */
6737 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6743 {
6750 }
6754 /* If the second operand is constant, this is a multiplication
6755 or floor division, by a power of two, so we can treat it that
6756 way unless the multiplier or divisor overflows. Signed
6757 left-shift overflow is implementation-defined rather than
6758 undefined in C90, so do not convert signed left shift into
6759 multiplication. */
6762 /* const_binop may not detect overflow correctly,
6763 so check for it explicitly here. */
6772 ctype,
6774 t1),
6779 /* See if we can eliminate the operation on both sides. If we can, we
6780 can return a new PLUS or MINUS. If we can't, the only remaining
6781 cases where we can do anything are if the second operand is a
6782 constant. */
6789 /* If not multiplication, we can only do this if both operands
6790 are divisible by c. */
6793 {
6798 }
6800 /* If this was a subtraction, negate OP1 and set it to be an addition.
6801 This simplifies the logic below. */
6803 {
6805 /* If OP1 was not easily negatable, the constant may be OP0. */
6807 {
6810 }
6811 }
6816 /* If either OP1 or C are negative, this optimization is not safe for
6817 some of the division and remainder types while for others we need
6818 to change the code. */
6820 {
6828 }
6830 /* If it's a multiply or a division/modulus operation of a multiple
6831 of our constant, do the operation and verify it doesn't overflow. */
6835 {
6838 /* We allow the constant to overflow with wrapping semantics. */
6842 }
6843 else
6846 /* If we have an unsigned type, we cannot widen the operation since it
6847 will change the result if the original computation overflowed. */
6851 /* The last case is if we are a multiply. In that case, we can
6852 apply the distributive law to commute the multiply and addition
6853 if the multiplication of the constants doesn't overflow
6854 and overflow is defined. With undefined overflow
6855 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6856 But fold_plusminus_mult_expr would factor back any power-of-two
6857 value so do not distribute in the first place in this case. */
6865 op1);
6870 /* We have a special case here if we are doing something like
6871 (C * 8) % 4 since we know that's zero. */
6874 /* If the multiplication can overflow we cannot optimize this. */
6879 {
6882 }
6884 /* ... fall through ... */
6888 /* If we can extract our operation from the LHS, do so and return a
6889 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6890 do something only if the second operand is a constant. */
6906 /* If these are the same operation types, we can associate them
6907 assuming no overflow. */
6909 {
6924 }
6926 /* If these operations "cancel" each other, we have the main
6927 optimizations of this pass, which occur when either constant is a
6928 multiple of the other, in which case we replace this with either an
6929 operation or CODE or TCODE.
6931 If we have an unsigned type, we cannot do this since it will change
6932 the result if the original computation overflowed. */
6939 {
6942 {
6949 }
6952 {
6959 }
6960 }
6965 }
6968 }
6969 \f
6970 /* Return a node which has the indicated constant VALUE (either 0 or
6971 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6972 and is of the indicated TYPE. */
6974 tree
6976 {
6985 else
6987 }
6990 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6991 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6992 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6993 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6994 COND is the first argument to CODE; otherwise (as in the example
6995 given here), it is the second argument. TYPE is the type of the
6996 original expression. Return NULL_TREE if no simplification is
6997 possible. */
6999 static tree
7004 {
7012 /* Do not move possibly trapping operations into the conditional as this
7013 pessimizes code and causes gimplification issues when applied late. */
7021 {
7025 /* If this operand throws an expression, then it does not make
7026 sense to try to perform a logical or arithmetic operation
7027 involving it. */
7032 }
7035 {
7040 }
7041 else
7042 /* Detect the case of mixing vector and scalar types - bail out. */
7048 /* This transformation is only worthwhile if we don't have to wrap ARG
7049 in a SAVE_EXPR and the operation can be simplified without recursing
7050 on at least one of the branches once its pushed inside the COND_EXPR. */
7059 {
7063 else
7065 }
7067 {
7071 else
7073 }
7075 /* Check that we have simplified at least one of the branches. */
7080 }
7082 \f
7083 /* Subroutine of fold() that checks for the addition of +/- 0.0.
7085 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
7086 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
7087 ADDEND is the same as X.
7089 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7090 and finite. The problematic cases are when X is zero, and its mode
7091 has signed zeros. In the case of rounding towards -infinity,
7092 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7093 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7095 bool
7097 {
7101 /* Don't allow the fold with -fsignaling-nans. */
7105 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7109 /* There is no case that is safe for all rounding modes. */
7113 /* In a vector or complex, we would need to check the sign of all zeros. */
7119 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7123 /* The mode has signed zeros, and we have to honor their sign.
7124 In this situation, there is only one case we can return true for.
7125 X - 0 is the same as X with default rounding. */
7127 }
7129 /* Subroutine of match.pd that optimizes comparisons of a division by
7130 a nonzero integer constant against an integer constant, i.e.
7131 X/C1 op C2.
7133 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7134 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7136 enum tree_code
7139 {
7144 /* We have to do this the hard way to detect unsigned overflow.
7145 prod = int_const_binop (MULT_EXPR, c1, c2); */
7151 {
7155 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7158 }
7160 {
7163 {
7182 }
7183 }
7184 else
7185 {
7186 /* A negative divisor reverses the relational operators. */
7191 {
7210 }
7211 }
7224 }
7227 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7228 equality/inequality test, then return a simplified form of the test
7229 using a sign testing. Otherwise return NULL. TYPE is the desired
7230 result type. */
7232 static tree
7235 tree result_type)
7236 {
7237 /* If this is testing a single bit, we can optimize the test. */
7241 {
7242 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7243 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7247 /* This is only a win if casting to a signed type is cheap,
7248 i.e. when arg00's type is not a partial mode. */
7250 {
7253 result_type,
7256 }
7257 }
7260 }
7262 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7263 equality/inequality test, then return a simplified form of
7264 the test using shifts and logical operations. Otherwise return
7265 NULL. TYPE is the desired result type. */
7267 tree
7270 {
7271 /* If this is testing a single bit, we can optimize the test. */
7275 {
7284 /* First, see if we can fold the single bit test into a sign-bit
7285 test. */
7287 result_type);
7291 /* Otherwise we have (A & C) != 0 where C is a single bit,
7292 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7293 Similarly for (A & C) == 0. */
7295 /* If INNER is a right shift of a constant and it plus BITNUM does
7296 not overflow, adjust BITNUM and INNER. */
7302 {
7305 }
7307 /* If we are going to be able to omit the AND below, we must do our
7308 operations as unsigned. If we must use the AND, we have a choice.
7309 Normally unsigned is faster, but for some machines signed is. */
7327 /* Put the AND last so it can combine with more things. */
7330 /* Make sure to return the proper type. */
7334 }
7336 }
7338 /* Test whether it is preferable two swap two operands, ARG0 and
7339 ARG1, for example because ARG0 is an integer constant and ARG1
7340 isn't. */
7342 bool
7344 {
7358 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7359 for commutative and comparison operators. Ensuring a canonical
7360 form allows the optimizers to find additional redundancies without
7361 having to explicitly check for both orderings. */
7367 /* Put SSA_NAMEs last. */
7373 /* Put variables last. */
7380 }
7383 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7384 means A >= Y && A != MAX, but in this case we know that
7385 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7387 static tree
7389 {
7396 else
7405 {
7408 }
7410 {
7413 }
7414 else
7421 {
7422 /* Convert the pointer types into integer before taking the difference. */
7426 }
7427 else
7434 }
7436 /* Fold a sum or difference of at least one multiplication.
7437 Returns the folded tree or NULL if no simplification could be made. */
7439 static tree
7442 {
7446 /* (A * C) +- (B * C) -> (A+-B) * C.
7447 (A * C) +- A -> A * (C+-1).
7448 We are most concerned about the case where C is a constant,
7449 but other combinations show up during loop reduction. Since
7450 it is not difficult, try all four possibilities. */
7453 {
7456 }
7458 {
7461 }
7462 else
7463 {
7464 /* We cannot generate constant 1 for fract. */
7469 }
7471 {
7474 }
7476 {
7478 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7479 the purpose of this canonicalization. */
7483 {
7486 }
7487 else
7489 }
7490 else
7491 {
7492 /* We cannot generate constant 1 for fract. */
7497 }
7500 /* Prefer factoring a common non-constant. */
7510 /* No identical multiplicands; see if we can find a common
7511 power-of-two factor in non-power-of-two multiplies. This
7512 can help in multi-dimensional array access. */
7514 {
7517 HOST_WIDE_INT tmp;
7519 tree maybe_same;
7521 /* Move min of absolute values to int11. */
7523 {
7528 }
7529 else
7536 /* The remainder should not be a constant, otherwise we
7537 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7538 increased the number of multiplications necessary. */
7540 {
7548 }
7549 }
7556 /* We are neither factoring zero nor minus one. */
7564 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7565 same may be minus one and thus the multiplication may overflow. Perform
7566 the sum operation in an unsigned type. */
7571 /* If the sum evaluated to a constant that is not -INF the multiplication
7572 cannot overflow. */
7579 /* Do not resort to unsigned multiplication because
7580 we lose the no-overflow property of the expression. */
7582 }
7584 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7585 specified by EXPR into the buffer PTR of length LEN bytes.
7586 Return the number of bytes placed in the buffer, or zero
7587 upon failure. */
7589 static int
7591 {
7603 /* Dry run. */
7609 {
7611 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7612 number of bytes. */
7616 {
7623 else
7625 }
7626 else
7630 }
7632 }
7635 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7636 specified by EXPR into the buffer PTR of length LEN bytes.
7637 Return the number of bytes placed in the buffer, or zero
7638 upon failure. */
7640 static int
7642 {
7646 FIXED_VALUE_TYPE value;
7661 }
7664 /* Subroutine of native_encode_expr. Encode the REAL_CST
7665 specified by EXPR into the buffer PTR of length LEN bytes.
7666 Return the number of bytes placed in the buffer, or zero
7667 upon failure. */
7669 static int
7671 {
7677 /* There are always 32 bits in each long, no matter the size of
7678 the hosts long. We handle floating point representations with
7679 up to 192 bits. */
7688 /* Dry run. */
7697 {
7702 {
7709 else
7711 }
7712 else
7713 {
7716 {
7717 /* Reverse bytes within each long, or within the entire float
7718 if it's smaller than a long (for HFmode). */
7721 }
7722 }
7727 }
7729 }
7731 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7732 specified by EXPR into the buffer PTR of length LEN bytes.
7733 Return the number of bytes placed in the buffer, or zero
7734 upon failure. */
7736 static int
7738 {
7740 tree part;
7754 }
7756 /* Like native_encode_vector, but only encode the first COUNT elements.
7757 The other arguments are as for native_encode_vector. */
7759 static int
7762 {
7766 {
7767 /* This is the only case in which elements can be smaller than a byte.
7768 Element 0 is always in the lsb of the containing byte. */
7777 /* Zero the buffer and then set bits later where necessary. */
7786 {
7792 {
7795 }
7796 }
7798 }
7803 {
7805 {
7808 }
7819 }
7821 }
7823 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7824 specified by EXPR into the buffer PTR of length LEN bytes.
7825 Return the number of bytes placed in the buffer, or zero
7826 upon failure. */
7828 static int
7830 {
7835 }
7838 /* Subroutine of native_encode_expr. Encode the STRING_CST
7839 specified by EXPR into the buffer PTR of length LEN bytes.
7840 Return the number of bytes placed in the buffer, or zero
7841 upon failure. */
7843 static int
7845 {
7848 /* Wide-char strings are encoded in target byte-order so native
7849 encoding them is trivial. */
7864 else
7865 {
7868 {
7871 }
7873 }
7875 }
7878 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
7879 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
7880 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
7881 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
7882 sufficient to encode the entire EXPR, or if OFF is out of bounds.
7883 Otherwise, start at byte offset OFF and encode at most LEN bytes.
7884 Return the number of bytes placed in the buffer, or zero upon failure. */
7886 int
7888 {
7889 /* We don't support starting at negative offset and -1 is special. */
7894 {
7915 }
7916 }
7918 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
7919 NON_LVALUE_EXPRs and nops. */
7921 int
7924 {
7925 /* We don't support starting at negative offset and -1 is special. */
7931 {
7946 {
7947 HOST_WIDE_INT min_index;
7965 {
7971 {
7979 }
7981 {
7985 }
7989 do
7990 {
7995 {
7997 {
8000 fieldsize);
8001 }
8003 ptr
8006 fieldsize,
8010 else
8011 {
8014 }
8015 }
8018 {
8019 /* Partial overlap. */
8024 {
8028 fieldsize);
8029 }
8030 else
8031 {
8035 }
8038 }
8040 }
8042 }
8044 }
8047 {
8054 {
8079 {
8086 else
8092 }
8101 {
8102 /* FIXME: Handle PDP endian. */
8122 else
8135 /* If the bitfield does not start at byte boundary, handle
8136 the partial byte at the start. */
8139 {
8141 {
8145 }
8146 else
8147 {
8151 }
8152 }
8153 /* If the bitfield does not end at byte boundary, handle
8154 the partial byte at the end. */
8158 {
8160 {
8165 }
8166 else
8167 {
8172 }
8173 }
8178 else
8179 {
8180 /* Partial overlap. */
8183 {
8186 }
8190 }
8192 }
8197 {
8200 fieldsize,
8203 }
8204 else
8205 {
8206 /* Partial overlap. */
8211 {
8215 fieldsize);
8216 }
8217 else
8218 {
8222 }
8225 }
8226 }
8228 }
8230 }
8231 }
8234 /* Subroutine of native_interpret_expr. Interpret the contents of
8235 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8236 If the buffer cannot be interpreted, return NULL_TREE. */
8238 static tree
8240 {
8250 }
8253 /* Subroutine of native_interpret_expr. Interpret the contents of
8254 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8255 If the buffer cannot be interpreted, return NULL_TREE. */
8257 static tree
8259 {
8262 double_int result;
8263 FIXED_VALUE_TYPE fixed_value;
8273 }
8276 /* Subroutine of native_interpret_expr. Interpret the contents of
8277 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8278 If the buffer cannot be interpreted, return NULL_TREE. */
8280 static tree
8282 {
8286 /* There are always 32 bits in each long, no matter the size of
8287 the hosts long. We handle floating point representations with
8288 up to 192 bits. */
8289 REAL_VALUE_TYPE r;
8299 {
8300 /* Both OFFSET and BYTE index within a long;
8301 bitpos indexes the whole float. */
8304 {
8311 else
8313 }
8314 else
8315 {
8318 {
8319 /* Reverse bytes within each long, or within the entire float
8320 if it's smaller than a long (for HFmode). */
8323 }
8324 }
8328 }
8333 {
8334 /* For floating point values in composite modes, punt if this folding
8335 doesn't preserve bit representation. As the mode doesn't have fixed
8336 precision while GCC pretends it does, there could be valid values that
8337 GCC can't really represent accurately. See PR95450. */
8342 }
8344 }
8347 /* Subroutine of native_interpret_expr. Interpret the contents of
8348 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8349 If the buffer cannot be interpreted, return NULL_TREE. */
8351 static tree
8353 {
8368 }
8370 /* Read a vector of type TYPE from the target memory image given by BYTES,
8371 which contains LEN bytes. The vector is known to be encodable using
8372 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8374 Return the vector on success, otherwise return null. */
8376 static tree
8380 {
8384 {
8385 /* This is the only case in which elements can be smaller than a byte.
8386 Element 0 is always in the lsb of the containing byte. */
8393 {
8400 }
8402 }
8410 {
8416 }
8418 }
8420 /* Subroutine of native_interpret_expr. Interpret the contents of
8421 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8422 If the buffer cannot be interpreted, return NULL_TREE. */
8424 static tree
8426 {
8427 tree etype;
8438 }
8441 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8442 the buffer PTR of length LEN as a constant of type TYPE. For
8443 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8444 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8445 return NULL_TREE. */
8447 tree
8449 {
8451 {
8473 }
8474 }
8476 /* Returns true if we can interpret the contents of a native encoding
8477 as TYPE. */
8479 bool
8481 {
8483 {
8496 }
8497 }
8499 /* Routines for manipulation of native_encode_expr encoded data if the encoded
8500 or extracted constant positions and/or sizes aren't byte aligned. */
8502 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
8503 bits between adjacent elements. AMNT should be within
8504 [0, BITS_PER_UNIT).
8505 Example, AMNT = 2:
8506 00011111|11100000 << 2 = 01111111|10000000
8507 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
8509 void
8512 {
8521 {
8527 {
8530 }
8531 }
8532 }
8534 /* Like shift_bytes_in_array_left but for big-endian.
8535 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
8536 bits between adjacent elements. AMNT should be within
8537 [0, BITS_PER_UNIT).
8538 Example, AMNT = 2:
8539 00011111|11100000 >> 2 = 00000111|11111000
8540 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
8542 void
8545 {
8553 {
8560 }
8561 }
8563 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
8564 directly on the VECTOR_CST encoding, in a way that works for variable-
8565 length vectors. Return the resulting VECTOR_CST on success or null
8566 on failure. */
8568 static tree
8570 {
8582 /* We can only preserve the semantics of a stepped pattern if the new
8583 vector element is an integer of the same size. */
8588 /* The number of bits needed to encode one element from every pattern
8589 of the original vector. */
8590 unsigned int expr_sequence_bits
8593 /* The number of bits needed to encode one element from every pattern
8594 of the result. */
8595 unsigned int type_sequence_bits
8598 /* Don't try to read more bytes than are available, which can happen
8599 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
8600 The general VIEW_CONVERT handling can cope with that case, so there's
8601 no point complicating things here. */
8604 BITS_PER_UNIT);
8609 /* Get enough bytes of EXPR to form the new encoding. */
8617 /* Reencode the bytes as TYPE. */
8621 }
8623 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
8624 TYPE at compile-time. If we're unable to perform the conversion
8625 return NULL_TREE. */
8627 static tree
8629 {
8630 /* We support up to 512-bit values (for V8DFmode). */
8634 /* Check that the host and target are sane. */
8647 }
8649 /* Build an expression for the address of T. Folds away INDIRECT_REF
8650 to avoid confusing the gimplify process. */
8652 tree
8654 {
8655 /* The size of the object is not relevant when talking about its address. */
8660 {
8665 }
8668 {
8673 }
8680 {
8685 }
8686 else
8690 }
8692 /* Build an expression for the address of T. */
8694 tree
8696 {
8700 }
8702 /* Fold a unary expression of code CODE and type TYPE with operand
8703 OP0. Return the folded expression if folding is successful.
8704 Otherwise, return NULL_TREE. */
8706 tree
8708 {
8709 tree tem;
8710 tree arg0;
8718 {
8721 {
8722 /* Don't use STRIP_NOPS, because signedness of argument type
8723 matters. */
8725 }
8726 else
8727 {
8728 /* Strip any conversions that don't change the mode. This
8729 is safe for every expression, except for a comparison
8730 expression because its signedness is derived from its
8731 operands.
8733 Note that this is done as an internal manipulation within
8734 the constant folder, in order to find the simplest
8735 representation of the arguments so that their form can be
8736 studied. In any cases, the appropriate type conversions
8737 should be put back in the tree that will get out of the
8738 constant folder. */
8740 }
8743 {
8746 {
8750 }
8751 }
8752 }
8759 {
8766 {
8780 /* If this was a conversion, and all we did was to move into
8781 inside the COND_EXPR, bring it back out. But leave it if
8782 it is a conversion from integer to integer and the
8783 result precision is no wider than a word since such a
8784 conversion is cheap and may be optimized away by combine,
8785 while it couldn't if it were outside the COND_EXPR. Then return
8786 so we don't get into an infinite recursion loop taking the
8787 conversion out and then back in. */
8799 && (INTEGRAL_TYPE_P
8812 }
8813 }
8816 {
8822 CASE_CONVERT:
8826 {
8827 /* If we have (type) (a CMP b) and type is an integral type, return
8828 new expression involving the new type. Canonicalize
8829 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
8830 non-integral type.
8831 Do not fold the result as that would not simplify further, also
8832 folding again results in recursions. */
8842 }
8844 /* Handle (T *)&A.B.C for A being of type T and B and C
8845 living at offset zero. This occurs frequently in
8846 C++ upcasting and then accessing the base. */
8850 {
8852 tree offset;
8853 machine_mode mode;
8855 tree base
8859 /* If the reference was to a (constant) zero offset, we can use
8860 the address of the base if it has the same base type
8861 as the result type and the pointer type is unqualified. */
8869 }
8873 /* Detect assigning a bitfield. */
8875 && DECL_BIT_FIELD
8877 {
8878 /* Don't leave an assignment inside a conversion
8879 unless assigning a bitfield. */
8881 /* First do the assignment, then return converted constant. */
8886 }
8888 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
8889 constants (if x has signed type, the sign bit cannot be set
8890 in c). This folds extension into the BIT_AND_EXPR.
8891 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
8892 very likely don't have maximal range for their precision and this
8893 transformation effectively doesn't preserve non-maximal ranges. */
8897 {
8908 <= HOST_BITS_PER_WIDE_INT
8910 {
8914 cst &= HOST_WIDE_INT_M1U
8918 && !flag_syntax_only
8921 {
8925 }
8926 }
8928 {
8933 }
8934 }
8936 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
8937 cast (T1)X will fold away. We assume that this happens when X itself
8938 is a cast. */
8942 {
8946 return fold_build_pointer_plus_loc
8948 }
8950 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
8951 of the same precision, and X is an integer type not narrower than
8952 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
8958 {
8964 }
8966 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
8967 type of X and Y (integer types only). */
8972 {
8973 /* Be careful not to introduce new overflows. */
8974 tree mult_type;
8977 else
8981 {
8988 }
8989 }
8995 {
9002 }
9013 /* Convert fabs((double)float) into (double)fabsf(float). */
9016 {
9022 targ0));
9023 }
9027 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9046 /* Note that the operand of this must be an int
9047 and its values must be 0 or 1.
9048 ("true" is a fixed value perhaps depending on the language,
9049 but we don't handle values other than 1 correctly yet.) */
9056 /* Fold *&X to X if X is an lvalue. */
9058 {
9065 }
9071 }
9074 /* If the operation was a conversion do _not_ mark a resulting constant
9075 with TREE_OVERFLOW if the original constant was not. These conversions
9076 have implementation defined behavior and retaining the TREE_OVERFLOW
9077 flag here would confuse later passes such as VRP. */
9078 tree
9081 {
9090 }
9092 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9093 operands OP0 and OP1. LOC is the location of the resulting expression.
9094 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9095 Return the folded expression if folding is successful. Otherwise,
9096 return NULL_TREE. */
9097 static tree
9100 {
9101 tree tem;
9103 /* We only do these simplifications if we are optimizing. */
9107 /* Check for things like (A || B) && (A || C). We can convert this
9108 to A || (B && C). Note that either operator can be any of the four
9109 truth and/or operations and the transformation will still be
9110 valid. Also note that we only care about order for the
9111 ANDIF and ORIF operators. If B contains side effects, this
9112 might change the truth-value of A. */
9119 {
9139 /* This case if tricky because we must either have commutative
9140 operators or else A10 must not have side-effects. */
9146 a01);
9147 }
9149 /* See if we can build a range comparison. */
9155 {
9159 }
9163 {
9167 }
9169 /* Check for the possibility of merging component references. If our
9170 lhs is another similar operation, try to merge its rhs with our
9171 rhs. Then try to merge our lhs and rhs. */
9182 logical_op_non_short_circuit
9185 && !flag_sanitize_coverage
9190 {
9197 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9198 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9199 We don't want to pack more than two leafs to a non-IF AND/OR
9200 expression.
9201 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9202 equal to IF-CODE, then we don't want to add right-hand operand.
9203 If the inner right-hand side of left-hand operand has
9204 side-effects, or isn't simple, then we can't add to it,
9205 as otherwise we might destroy if-sequence. */
9208 /* Needed for sequence points to handle trappings, and
9209 side-effects. */
9211 {
9213 arg1);
9215 tem);
9216 }
9217 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9218 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9221 /* Needed for sequence points to handle trappings, and
9222 side-effects. */
9224 {
9229 }
9230 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9231 into (A OR B).
9232 For sequence point consistancy, we need to check for trapping,
9233 and side-effects. */
9237 }
9240 }
9242 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9243 by changing CODE to reduce the magnitude of constants involved in
9244 ARG0 of the comparison.
9245 Returns a canonicalized comparison tree if a simplification was
9246 possible, otherwise returns NULL_TREE.
9247 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9248 valid if signed overflow is undefined. */
9250 static tree
9254 {
9259 /* Match A +- CST code arg1. We can change this only if overflow
9260 is undefined. */
9263 /* In principle pointers also have undefined overflow behavior,
9264 but that causes problems elsewhere. */
9271 /* Identify the constant in arg0 and its sign. */
9275 /* Overflowed constants and zero will cause problems. */
9280 /* See if we can reduce the magnitude of the constant in
9281 arg0 by changing the comparison code. */
9282 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9286 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9290 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9294 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9298 else
9302 /* Now build the constant reduced in magnitude. But not if that
9303 would produce one outside of its types range. */
9319 }
9321 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9322 overflow further. Try to decrease the magnitude of constants involved
9323 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9324 and put sole constants at the second argument position.
9325 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9327 static tree
9330 {
9331 tree t;
9336 /* Try canonicalization by simplifying arg0. */
9341 {
9345 }
9347 /* Try canonicalization by simplifying arg1 using the swapped
9348 comparison. */
9356 }
9358 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9359 space. This is used to avoid issuing overflow warnings for
9360 expressions like &p->x which cannot wrap. */
9362 static bool
9364 {
9371 poly_wide_int wi_offset;
9377 else
9382 precision);
9397 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9398 array. */
9407 }
9409 /* Return a positive integer when the symbol DECL is known to have
9410 a nonzero address, zero when it's known not to (e.g., it's a weak
9411 symbol), and a negative integer when the symbol is not yet in the
9412 symbol table and so whether or not its address is zero is unknown.
9413 For function local objects always return positive integer. */
9414 static int
9416 {
9421 /* Function local objects are never NULL. */
9429 }
9431 /* Subroutine of fold_binary. This routine performs all of the
9432 transformations that are common to the equality/inequality
9433 operators (EQ_EXPR and NE_EXPR) and the ordering operators
9434 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
9435 fold_binary should call fold_binary. Fold a comparison with
9436 tree code CODE and type TYPE with operands OP0 and OP1. Return
9437 the folded comparison or NULL_TREE. */
9439 static tree
9442 {
9452 /* For comparisons of pointers we can decompose it to a compile time
9453 comparison of the base objects and the offsets into the object.
9454 This requires at least one operand being an ADDR_EXPR or a
9455 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
9461 {
9464 machine_mode mode;
9468 /* Get base and offset for the access. Strip ADDR_EXPR for
9469 get_inner_reference, but put it back by stripping INDIRECT_REF
9470 off the base object if possible. indirect_baseN will be true
9471 if baseN is not an address but refers to the object itself. */
9474 {
9475 base0
9481 else
9483 }
9485 {
9489 {
9490 base0
9496 else
9498 }
9501 else
9505 {
9512 }
9513 }
9517 {
9518 base1
9524 else
9526 }
9528 {
9532 {
9533 base1
9539 else
9541 }
9544 else
9548 {
9555 }
9556 }
9558 /* If we have equivalent bases we might be able to simplify. */
9562 {
9563 /* We can fold this expression to a constant if the non-constant
9564 offset parts are equal. */
9568 && (equality_code
9569 || (indirect_base0
9572 {
9578 "occur when comparing P +- C1 with "
9580 WARN_STRICT_OVERFLOW_CONDITIONAL);
9583 {
9621 }
9622 }
9623 /* We can simplify the comparison to a comparison of the variable
9624 offset parts if the constant offset parts are equal.
9625 Be careful to use signed sizetype here because otherwise we
9626 mess with array offsets in the wrong way. This is possible
9627 because pointer arithmetic is restricted to retain within an
9628 object and overflow on pointer differences is undefined as of
9629 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
9631 && (equality_code
9632 || (indirect_base0
9635 {
9636 /* By converting to signed sizetype we cover middle-end pointer
9637 arithmetic which operates on unsigned pointer types of size
9638 type size and ARRAY_REF offsets which are properly sign or
9639 zero extended from their type in case it is narrower than
9640 sizetype. */
9643 else
9647 else
9654 "occur when comparing P +- C1 with "
9656 WARN_STRICT_OVERFLOW_COMPARISON);
9659 }
9660 }
9661 /* For equal offsets we can simplify to a comparison of the
9662 base addresses. */
9664 && (indirect_base0
9666 && (indirect_base1
9671 {
9677 }
9678 /* Comparison between an ordinary (non-weak) symbol and a null
9679 pointer can be eliminated since such symbols must have a non
9680 null address. In C, relational expressions between pointers
9681 to objects and null pointers are undefined. The results
9682 below follow the C++ rules with the additional property that
9683 every object pointer compares greater than a null pointer.
9684 */
9687 /* Avoid folding references to struct members at offset 0 to
9688 prevent tests like '&ptr->firstmember == 0' from getting
9689 eliminated. When ptr is null, although the -> expression
9690 is strictly speaking invalid, GCC retains it as a matter
9691 of QoI. See PR c/44555. */
9694 && indirect_base0
9695 /* The caller guarantees that when one of the arguments is
9696 constant (i.e., null in this case) it is second. */
9698 {
9700 {
9711 }
9712 }
9713 }
9715 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
9716 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
9717 the resulting offset is smaller in absolute value than the
9718 original one and has the same sign. */
9727 {
9732 tree cst;
9734 "occur when combining constants around "
9737 /* Put the constant on the side where it doesn't overflow and is
9738 of lower absolute value and of same sign than before. */
9745 {
9748 variable1,
9752 }
9760 {
9766 variable2);
9767 }
9768 }
9774 /* If we are comparing an expression that just has comparisons
9775 of two integer values, arithmetic expressions of those comparisons,
9776 and constants, we can simplify it. There are only three cases
9777 to check: the two values can either be equal, the first can be
9778 greater, or the second can be greater. Fold the expression for
9779 those three values. Since each value must be 0 or 1, we have
9780 eight possibilities, each of which corresponds to the constant 0
9781 or 1 or one of the six possible comparisons.
9783 This handles common cases like (a > b) == 0 but also handles
9784 expressions like ((x > y) - (y > x)) > 0, which supposedly
9785 occur in macroized code. */
9788 {
9792 /* Don't handle degenerate cases here; they should already
9793 have been handled anyway. */
9802 {
9806 /* We can't just pass T to eval_subst in case cval1 or cval2
9807 was the same as ARG1. */
9809 tree high_result
9813 arg1);
9814 tree equal_result
9818 arg1);
9819 tree low_result
9823 arg1);
9825 /* All three of these results should be 0 or 1. Confirm they are.
9826 Then use those values to select the proper code to use. */
9831 {
9832 /* Make a 3-bit mask with the high-order bit being the
9833 value for `>', the next for '=', and the low for '<'. */
9837 {
9839 /* Always false. */
9860 /* Always true. */
9862 }
9865 }
9866 }
9867 }
9870 }
9873 /* Subroutine of fold_binary. Optimize complex multiplications of the
9874 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
9875 argument EXPR represents the expression "z" of type TYPE. */
9877 static tree
9879 {
9884 {
9887 }
9889 {
9892 }
9893 else
9894 {
9898 }
9907 }
9910 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
9911 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
9912 true if successful. */
9914 static bool
9916 {
9921 {
9924 }
9926 {
9932 else
9934 }
9935 else
9941 }
9943 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
9944 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
9945 NULL_TREE otherwise. */
9947 tree
9949 {
9970 {
9971 HOST_WIDE_INT index;
9977 }
9980 {
9986 }
9987 else
9989 }
9991 /* Try to fold a pointer difference of type TYPE two address expressions of
9992 array references AREF0 and AREF1 using location LOC. Return a
9993 simplified expression for the difference or NULL_TREE. */
9995 static tree
9999 {
10004 /* If the bases are array references as well, recurse. If the bases
10005 are pointer indirections compute the difference of the pointers.
10006 If the bases are equal, we are set. */
10009 && (base_offset
10011 use_pointer_diff)))
10014 && (base_offset
10015 = use_pointer_diff
10025 {
10031 base_offset,
10034 }
10036 }
10038 /* If the real or vector real constant CST of type TYPE has an exact
10039 inverse, return it, else return NULL. */
10041 tree
10043 {
10044 REAL_VALUE_TYPE r;
10045 tree unit_type;
10046 machine_mode mode;
10049 {
10059 {
10063 tree_vector_builder elts;
10068 {
10073 }
10076 }
10080 }
10081 }
10083 /* Mask out the tz least significant bits of X of type TYPE where
10084 tz is the number of trailing zeroes in Y. */
10085 static wide_int
10087 {
10092 }
10094 /* Return true when T is an address and is known to be nonzero.
10095 For floating point we further ensure that T is not denormal.
10096 Similar logic is present in nonzero_address in rtlanal.h.
10098 If the return value is based on the assumption that signed overflow
10099 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10100 change *STRICT_OVERFLOW_P. */
10102 static bool
10104 {
10108 /* Doing something useful for floating point would need more work. */
10114 {
10117 strict_overflow_p);
10123 strict_overflow_p);
10131 }
10134 {
10137 strict_overflow_p);
10145 strict_overflow_p);
10160 strict_overflow_p);
10164 strict_overflow_p);
10167 {
10179 }
10183 }
10185 }
10187 /* Return true when T is an address and is known to be nonzero.
10188 Handle warnings about undefined signed overflow. */
10190 bool
10192 {
10199 "determining that expression is always "
10201 WARN_STRICT_OVERFLOW_MISC);
10203 }
10205 /* Return true if T is known not to be equal to an integer W. */
10207 bool
10209 {
10210 value_range vr;
10212 {
10223 /* If T has some known zero bits and W has any of those bits set,
10224 then T is known not to be equal to W. */
10232 }
10233 }
10235 /* Fold a binary expression of code CODE and type TYPE with operands
10236 OP0 and OP1. LOC is the location of the resulting expression.
10237 Return the folded expression if folding is successful. Otherwise,
10238 return NULL_TREE. */
10240 tree
10243 {
10258 /* Strip any conversions that don't change the mode. This is
10259 safe for every expression, except for a comparison expression
10260 because its signedness is derived from its operands. So, in
10261 the latter case, only strip conversions that don't change the
10262 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10263 preserved.
10265 Note that this is done as an internal manipulation within the
10266 constant folder, in order to find the simplest representation
10267 of the arguments so that their form can be studied. In any
10268 cases, the appropriate type conversions should be put back in
10269 the tree that will get out of the constant folder. */
10272 {
10275 }
10276 else
10277 {
10280 }
10282 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10283 constant but we can't do arithmetic on them. */
10285 {
10288 {
10292 }
10293 }
10295 /* If this is a commutative operation, and ARG0 is a constant, move it
10296 to ARG1 to reduce the number of tests below. */
10301 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10302 to ARG1 to reduce the number of tests below. */
10311 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10313 First check for cases where an arithmetic operation is applied to a
10314 compound, conditional, or comparison operation. Push the arithmetic
10315 operation inside the compound or conditional to see if any folding
10316 can then be done. Convert comparison to conditional for this purpose.
10317 The also optimizes non-constant cases that used to be done in
10318 expand_expr.
10320 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10321 one of the operands is a comparison and the other is a comparison, a
10322 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10323 code below would make the expression more complex. Change it to a
10324 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10325 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10338 {
10342 boolean_type_node,
10350 }
10354 {
10356 {
10361 tem);
10362 }
10364 {
10369 tem);
10370 }
10375 {
10381 }
10386 {
10392 }
10393 }
10396 {
10398 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10401 {
10407 }
10409 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10412 {
10413 tree base;
10414 poly_int64 coffset;
10423 }
10428 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
10434 arg1),
10436 arg0)));
10442 {
10443 /* X + (X / CST) * -CST is X % CST. */
10448 {
10457 cst0));
10458 }
10459 }
10461 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
10462 one. Make sure the type is not saturating and has the signedness of
10463 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10464 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10471 {
10475 }
10478 {
10479 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
10480 (plus (plus (mult) (mult)) (foo)) so that we can
10481 take advantage of the factoring cases below. */
10490 {
10496 else
10509 parg0),
10511 marg)),
10515 return
10521 parg1)));
10522 }
10523 }
10524 else
10525 {
10526 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
10527 to __complex__ ( x, y ). This is not the same for SNaNs or
10528 if signed zeros are involved. */
10532 {
10539 {
10543 {
10549 }
10551 {
10557 }
10558 }
10559 }
10561 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
10562 We associate floats only if the user has specified
10563 -fassociative-math. */
10567 {
10572 {
10573 tree tree0;
10576 }
10577 }
10578 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
10579 We associate floats only if the user has specified
10580 -fassociative-math. */
10584 {
10589 {
10590 tree tree0;
10593 }
10594 }
10595 }
10597 bit_rotate:
10598 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
10599 is a rotate of A by C1 bits. */
10600 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
10601 is a rotate of A by B bits.
10602 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
10603 though in this case CODE must be | and not + or ^, otherwise
10604 it doesn't return A when B is 0. */
10605 {
10607 tree rtype;
10616 /* Only create rotates in complete modes. Other cases are not
10617 expanded properly. */
10620 {
10633 {
10638 }
10643 {
10646 code0 == LSHIFT_EXPR
10649 }
10651 {
10661 {
10665 orig_tree01);
10667 }
10668 }
10672 {
10683 {
10687 orig_tree01);
10689 }
10690 }
10691 }
10692 }
10694 associate:
10695 /* In most languages, can't associate operations on floats through
10696 parentheses. Rather than remember where the parentheses were, we
10697 don't associate floats at all, unless the user has specified
10698 -fassociative-math.
10699 And, we need to make sure type is not saturating. */
10703 {
10709 /* Split both trees into variables, constants, and literals. Then
10710 associate each group together, the constants with literals,
10711 then the result with variables. This increases the chances of
10712 literals being recombined later and of generating relocatable
10713 expressions for the sum of a constant and literal. */
10721 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
10725 /* With undefined overflow prefer doing association in a type
10726 which wraps on overflow, if that is one of the operand types. */
10729 {
10737 }
10739 /* With undefined overflow we can only associate constants with one
10740 variable, and constants whose association doesn't overflow. */
10743 {
10745 {
10746 /* ??? If split_tree would handle NEGATE_EXPR we could
10747 simply reject these cases and the allowed cases would
10748 be the var0/minus_var1 ones. */
10754 {
10757 }
10764 {
10767 }
10773 /* The only case we can still associate with two variables
10774 is if they cancel out. */
10778 }
10784 }
10786 /* Only do something if we found more than two objects. Otherwise,
10787 nothing has changed and we risk infinite recursion. */
10795 {
10807 {
10811 }
10813 {
10817 }
10819 /* Preserve the MINUS_EXPR if the negative part of the literal is
10820 greater than the positive part. Otherwise, the multiplicative
10821 folding code (i.e extract_muldiv) may be fooled in case
10822 unsigned constants are subtracted, like in the following
10823 example: ((X*2 + 4) - 8U)/2. */
10825 {
10829 /* But avoid ending up with only negated parts. */
10831 {
10835 }
10836 else
10837 {
10841 }
10842 }
10844 /* Don't introduce overflows through reassociation. */
10849 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
10856 /* Eliminate minus_con0. */
10858 {
10865 else
10868 }
10870 /* Eliminate minus_var0. */
10872 {
10876 else
10879 }
10881 return
10884 }
10885 }
10891 /* Fold &a[i] - &a[j] to i-j. */
10896 {
10900 code
10904 }
10906 /* Further transformations are not for pointers. */
10910 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
10913 /* If arg0 is e.g. unsigned int and type is int, then this could
10914 introduce UB, because if A is INT_MIN at runtime, the original
10915 expression can be well defined while the latter is not.
10916 See PR83269. */
10925 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
10926 __complex__ ( x, -y ). This is not the same for SNaNs or if
10927 signed zeros are involved. */
10931 {
10938 {
10942 {
10944 arg1r ? arg1r
10949 }
10951 {
10955 arg1i ? arg1i
10958 }
10959 }
10960 }
10962 /* A - B -> A + (-B) if B is easily negatable. */
10966 /* Avoid this transformation if B is a positive REAL_CST. */
10974 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
10975 one. Make sure the type is not saturating and has the signedness of
10976 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10977 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10984 {
10988 }
10994 {
10995 /* Transform x * -C into -x * C if x is easily negatable. */
11010 {
11013 "occur when simplifying "
11015 WARN_STRICT_OVERFLOW_MISC);
11017 }
11019 /* Optimize z * conj(z) for integer complex numbers. */
11026 }
11027 else
11028 {
11029 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11030 This is not the same for NaNs or if signed zeros are
11031 involved. */
11037 {
11040 return
11046 return
11051 }
11053 /* Optimize z * conj(z) for floating point complex numbers.
11054 Guarded by flag_unsafe_math_optimizations as non-finite
11055 imaginary components don't produce scalar results. */
11064 }
11068 /* Canonicalize (X & C1) | C2. */
11072 {
11077 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11085 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11087 {
11090 }
11092 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11093 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11094 mode which allows further optimizations. */
11099 {
11104 {
11107 }
11108 }
11111 {
11116 }
11117 }
11119 /* See if this can be simplified into a rotate first. If that
11120 is unsuccessful continue in the association code. */
11124 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11132 /* See if this can be simplified into a rotate first. If that
11133 is unsuccessful continue in the association code. */
11137 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11142 {
11143 tree tem2;
11150 }
11151 /* Fold ~X & 1 as (X & 1) == 0. */
11155 {
11156 tree tem2;
11163 }
11164 /* Fold !X & 1 as X == 0. */
11167 {
11171 }
11173 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11174 multiple of 1 << CST. */
11176 {
11183 }
11185 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11186 bits from CST2. */
11190 {
11192 wide_int masked
11199 {
11200 /* Avoid the transform if arg1 is a mask of some
11201 mode which allows further optimizations. */
11208 }
11209 }
11211 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11214 {
11219 return
11221 }
11226 /* Don't touch a floating-point divide by zero unless the mode
11227 of the constant can represent infinity. */
11233 /* (-A) / (-B) -> A / B */
11245 /* Fall through */
11248 /* Simplify A / (B << N) where A and B are positive and B is
11249 a power of 2, to A >> (N + log2(B)). */
11254 {
11257 {
11265 WARN_STRICT_OVERFLOW_MISC);
11271 }
11272 }
11274 /* Fall through */
11282 /* Convert -A / -B to A / B when the type is signed and overflow is
11283 undefined. */
11287 {
11290 "when distributing negation across "
11292 WARN_STRICT_OVERFLOW_MISC);
11297 }
11301 {
11304 "when distributing negation across "
11306 WARN_STRICT_OVERFLOW_MISC);
11311 }
11313 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11314 operation, EXACT_DIV_EXPR.
11316 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11317 At one time others generated faster code, it's not clear if they do
11318 after the last round to changes to the DIV code in expmed.c. */
11329 {
11333 WARN_STRICT_OVERFLOW_MISC);
11335 }
11347 {
11351 WARN_STRICT_OVERFLOW_MISC);
11353 }
11361 /* Since negative shift count is not well-defined,
11362 don't try to compute it in the compiler. */
11368 /* If we have a rotate of a bit operation with the rotate count and
11369 the second operand of the bit operation both constant,
11370 permute the two operations. */
11376 {
11384 }
11386 /* Two consecutive rotates adding up to the some integer
11387 multiple of the precision of the type can be ignored. */
11403 /* Note that the operands of this must be ints
11404 and their values must be 0 or 1.
11405 ("true" is a fixed value perhaps depending on the language.) */
11406 /* If first arg is constant zero, return it. */
11409 /* FALLTHRU */
11411 /* If either arg is constant true, drop it. */
11415 /* Preserve sequence points. */
11418 /* If second arg is constant zero, result is zero, but first arg
11419 must be evaluated. */
11422 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11423 case will be handled here. */
11427 /* !X && X is always false. */
11431 /* X && !X is always false. */
11436 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11437 means A >= Y && A != MAX, but in this case we know that
11438 A < X <= MAX. */
11442 {
11450 }
11459 /* Note that the operands of this must be ints
11460 and their values must be 0 or true.
11461 ("true" is a fixed value perhaps depending on the language.) */
11462 /* If first arg is constant true, return it. */
11465 /* FALLTHRU */
11467 /* If either arg is constant zero, drop it. */
11471 /* Preserve sequence points. */
11474 /* If second arg is constant true, result is true, but we must
11475 evaluate first arg. */
11478 /* Likewise for first arg, but note this only occurs here for
11479 TRUTH_OR_EXPR. */
11483 /* !X || X is always true. */
11487 /* X || !X is always true. */
11492 /* (X && !Y) || (!X && Y) is X ^ Y */
11495 {
11512 }
11521 /* If the second arg is constant zero, drop it. */
11524 /* If the second arg is constant true, this is a logical inversion. */
11526 {
11529 }
11530 /* Identical arguments cancel to zero. */
11534 /* !X ^ X is always true. */
11539 /* X ^ !X is always true. */
11555 /* bool_var != 1 becomes !bool_var. */
11562 /* bool_var == 0 becomes !bool_var. */
11569 /* !exp != 0 becomes !exp */
11574 /* If this is an EQ or NE comparison with zero and ARG0 is
11575 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11576 two operations, but the latter can be done in one less insn
11577 on machines that have only two-operand insns or on which a
11578 constant cannot be the first operand. */
11581 {
11586 {
11593 arg1);
11594 }
11597 {
11604 arg1);
11605 }
11606 }
11608 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
11609 C1 is a valid shift constant, and C2 is a power of two, i.e.
11610 a single bit. */
11614 {
11619 {
11624 /* Check for a valid shift count. */
11626 {
11630 /* If (C2 << C1) doesn't overflow, then
11631 ((X >> C1) & C2) != 0 can be rewritten as
11632 (X & (C2 << C1)) != 0. */
11634 {
11641 }
11642 /* Otherwise, for signed (arithmetic) shifts,
11643 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
11644 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
11650 /* Otherwise, of unsigned (logical) shifts,
11651 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
11652 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
11653 else
11657 arg000);
11658 }
11659 }
11660 }
11662 /* If this is a comparison of a field, we may be able to simplify it. */
11665 /* Handle the constant case even without -O
11666 to make sure the warnings are given. */
11668 {
11672 }
11674 /* Optimize comparisons of strlen vs zero to a compare of the
11675 first character of the string vs zero. To wit,
11676 strlen(ptr) == 0 => *ptr == 0
11677 strlen(ptr) != 0 => *ptr != 0
11678 Other cases should reduce to one of these two (or a constant)
11679 due to the return value of strlen being unsigned. */
11681 {
11689 {
11690 tree ptrtype
11692 TYPE_QUAL_CONST));
11698 }
11699 }
11701 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
11702 of X. Similarly fold (X >> C) == 0 into X >= 0. */
11706 {
11711 {
11713 {
11716 }
11719 }
11720 }
11722 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
11723 (X & C) == 0 when C is a single bit. */
11728 {
11735 arg1));
11736 }
11738 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
11739 constant C is a power of two, i.e. a single bit. */
11746 {
11750 }
11752 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
11753 when is C is a power of two, i.e. a single bit. */
11760 {
11766 }
11770 {
11773 }
11777 {
11784 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
11785 operand_equal_p guarantees no side-effects so we don't need
11786 to use omit_one_operand on Z. */
11790 arg10));
11794 arg11));
11798 arg10));
11802 arg11));
11804 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
11807 {
11813 }
11814 }
11816 /* Attempt to simplify equality/inequality comparisons of complex
11817 values. Only lower the comparison if the result is known or
11818 can be simplified to a single scalar comparison. */
11823 {
11828 {
11831 }
11832 else
11833 {
11836 }
11839 {
11842 }
11843 else
11844 {
11847 }
11851 {
11853 {
11858 }
11859 else
11860 {
11865 }
11866 }
11870 {
11872 {
11877 }
11878 else
11879 {
11884 }
11885 }
11886 }
11898 /* Transform comparisons of the form X +- C CMP X. */
11903 {
11908 /* (X - c) > X becomes false. */
11914 /* Likewise (X + c) < X becomes false. */
11920 /* Convert (X - c) <= X to true. */
11927 /* Convert (X + c) >= X to true. */
11933 }
11935 /* If we are comparing an ABS_EXPR with a constant, we can
11936 convert all the cases into explicit comparisons, but they may
11937 well not be faster than doing the ABS and one comparison.
11938 But ABS (X) <= C is a range comparison, which becomes a subtraction
11939 and a comparison, and is probably faster. */
11953 /* Convert ABS_EXPR<x> >= 0 to true. */
11960 {
11963 "when simplifying comparison of "
11965 WARN_STRICT_OVERFLOW_CONDITIONAL);
11968 arg0);
11969 }
11971 /* Convert ABS_EXPR<x> < 0 to false. */
11976 {
11979 "when simplifying comparison of "
11981 WARN_STRICT_OVERFLOW_CONDITIONAL);
11984 arg0);
11985 }
11987 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11988 and similarly for >= into !=. */
11998 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11999 otherwise Y might be >= # of bits in X's type and thus e.g.
12000 (unsigned char) (1 << Y) for Y 15 might be 0.
12001 If the cast is widening, then 1 << Y should have unsigned type,
12002 otherwise if Y is number of bits in the signed shift type minus 1,
12003 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12004 31 might be 0xffffffff80000000. */
12015 {
12021 }
12033 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12034 {
12046 }
12051 /* When pedantic, a compound expression can be neither an lvalue
12052 nor an integer constant expression. */
12055 /* Don't let (0, 0) be null pointer constant. */
12061 /* An ASSERT_EXPR should never be passed to fold_binary. */
12067 }
12069 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12070 ((A & N) + B) & M -> (A + B) & M
12071 Similarly if (N & M) == 0,
12072 ((A | N) + B) & M -> (A + B) & M
12073 and for - instead of + (or unary - instead of +)
12074 and/or ^ instead of |.
12075 If B is constant and (B & M) == 0, fold into A & M.
12077 This function is a helper for match.pd patterns. Return non-NULL
12078 type in which the simplified operation should be performed only
12079 if any optimization is possible.
12081 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12082 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12083 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12084 +/-. */
12085 tree
12090 {
12105 wide_int cst0;
12107 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12108 arg1 (M) is == (1LL << cst) - 1.
12109 Store C into PMOP[0] and D into PMOP[1]. */
12116 {
12123 {
12126 }
12129 /* If C or D is of the form (A & N) where
12130 (N & M) == M, or of the form (A | N) or
12131 (A ^ N) where (N & M) == 0, replace it with A. */
12137 /* If C or D is a N where (N & M) == 0, it can be
12138 omitted (replaced with 0). */
12143 /* Similarly, with C - N where (-N & M) == 0. */
12151 }
12153 /* Only build anything new if we optimized one or both arguments above. */
12159 else
12161 }
12163 /* Used by contains_label_[p1]. */
12165 struct contains_label_data
12166 {
12169 };
12171 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12172 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12173 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12175 static tree
12177 {
12180 {
12191 {
12199 }
12208 }
12209 }
12211 /* Return whether the sub-tree ST contains a label which is accessible from
12212 outside the sub-tree. */
12214 static bool
12216 {
12220 }
12222 /* Fold a ternary expression of code CODE and type TYPE with operands
12223 OP0, OP1, and OP2. Return the folded expression if folding is
12224 successful. Otherwise, return NULL_TREE. */
12226 tree
12229 {
12230 tree tem;
12237 /* If this is a commutative operation, and OP0 is a constant, move it
12238 to OP1 to reduce the number of tests below. */
12247 /* Strip any conversions that don't change the mode. This is safe
12248 for every expression, except for a comparison expression because
12249 its signedness is derived from its operands. So, in the latter
12250 case, only strip conversions that don't change the signedness.
12252 Note that this is done as an internal manipulation within the
12253 constant folder, in order to find the simplest representation of
12254 the arguments so that their form can be studied. In any cases,
12255 the appropriate type conversions should be put back in the tree
12256 that will get out of the constant folder. */
12258 {
12261 }
12264 {
12267 }
12270 {
12273 }
12276 {
12280 {
12286 }
12291 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12292 so all simple results must be passed through pedantic_non_lvalue. */
12294 {
12297 /* Only optimize constant conditions when the selected branch
12298 has the same type as the COND_EXPR. This avoids optimizing
12299 away "c ? x : throw", where the throw has a void type.
12300 Avoid throwing away that operand which contains label. */
12307 }
12309 {
12316 {
12319 {
12327 }
12332 }
12333 }
12335 /* If we have A op B ? A : C, we may be able to convert this to a
12336 simpler expression, depending on the operation and the values
12337 of B and C. Signed zeros prevent all of these transformations,
12338 for reasons given above each one.
12340 Also try swapping the arguments and inverting the conditional. */
12344 {
12348 }
12353 {
12357 {
12361 }
12362 }
12364 /* If the second operand is simpler than the third, swap them
12365 since that produces better jump optimization results. */
12368 {
12370 /* See if this can be inverted. If it can't, possibly because
12371 it was a floating-point inequality comparison, don't do
12372 anything. */
12376 }
12378 /* Convert A ? 1 : 0 to simply A. */
12383 /* If we try to convert OP0 to our type, the
12384 call to fold will try to move the conversion inside
12385 a COND, which will recurse. In that case, the COND_EXPR
12386 is probably the best choice, so leave it alone. */
12390 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12391 over COND_EXPR in cases such as floating point comparisons. */
12400 arg0)));
12402 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12407 {
12408 /* sign_bit_p looks through both zero and sign extensions,
12409 but for this optimization only sign extensions are
12410 usable. */
12413 {
12416 {
12419 }
12421 }
12422 /* sign_bit_p only checks ARG1 bits within A's precision.
12423 If <sign bit of A> has wider type than A, bits outside
12424 of A's precision in <sign bit of A> need to be checked.
12425 If they are all 0, this optimization needs to be done
12426 in unsigned A's type, if they are all 1 in signed A's type,
12427 otherwise this can't be done. */
12433 {
12435 tree tem_type;
12448 {
12451 }
12453 {
12456 }
12457 else
12459 }
12462 return
12468 arg1)));
12469 }
12471 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12472 already handled above. */
12477 {
12487 op1);
12488 }
12490 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12491 is probably obsolete because the first operand should be a
12492 truth value (that's why we have the two cases above), but let's
12493 leave it in until we can confirm this for all front-ends. */
12501 /* operand_equal_p compares just value, not precision, so e.g.
12502 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
12503 second operand 32-bit -128, which is not a power of two (or vice
12504 versa. */
12511 /* Disable the transformations below for vectors, since
12512 fold_binary_op_with_conditional_arg may undo them immediately,
12513 yielding an infinite loop. */
12517 /* Convert A ? B : 0 into A && B if A and B are truth values. */
12526 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
12531 {
12533 /* Only perform transformation if ARG0 is easily inverted. */
12537 ? BIT_IOR_EXPR
12540 op1);
12541 }
12543 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
12548 {
12550 /* Only perform transformation if ARG0 is easily inverted. */
12556 op2);
12557 }
12559 /* Convert A ? 1 : B into A || B if A and B are truth values. */
12571 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
12572 of fold_ternary on them. */
12582 {
12584 unsigned HOST_WIDE_INT width
12595 {
12600 {
12602 {
12607 }
12613 }
12614 }
12615 }
12617 /* On constants we can use native encode/interpret to constant
12618 fold (nearly) all BIT_FIELD_REFs. */
12624 {
12627 /* Limit us to a reasonable amount of work. To relax the
12628 other limitations we need bit-shifting of the buffer
12629 and rounding up the size. */
12633 {
12635 unsigned HOST_WIDE_INT len
12640 {
12645 }
12646 }
12647 }
12652 /* Perform constant folding of BIT_INSERT_EXPR. */
12656 {
12657 /* Build a vector of integers from the tree mask. */
12658 vec_perm_builder builder;
12662 /* Create a vec_perm_indices for the integer vector. */
12667 }
12671 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
12674 {
12680 wide_int tem2
12684 }
12689 {
12691 unsigned HOST_WIDE_INT elsize
12694 {
12700 {
12706 }
12707 }
12708 }
12714 }
12716 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
12717 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
12718 constructor element index of the value returned. If the element is
12719 not found NULL_TREE is returned and *CTOR_IDX is updated to
12720 the index of the element after the ACCESS_INDEX position (which
12721 may be outside of the CTOR array). */
12723 tree
12726 {
12732 {
12735 {
12736 /* Static constructors for variably sized objects makes no sense. */
12739 /* ??? When it is obvious that the range is signed, treat it so. */
12744 {
12746 low_bound
12748 SIGNED);
12749 }
12750 else
12751 {
12754 }
12755 }
12756 }
12760 index_sgn);
12772 {
12773 /* Array constructor might explicitly set index, or specify a range,
12774 or leave index NULL meaning that it is next index after previous
12775 one. */
12777 {
12779 max_index = index
12781 else
12782 {
12785 index_sgn);
12786 max_index
12788 index_sgn);
12790 }
12791 }
12793 {
12799 }
12800 else
12803 /* Do we have match? */
12805 {
12807 {
12811 }
12812 }
12814 /* We're past the element we search for. Note during parsing
12815 the elements might not be sorted.
12816 ??? We should use a binary search and a flag on the
12817 CONSTRUCTOR as to whether elements are sorted in declaration
12818 order. */
12820 }
12824 }
12826 /* Perform constant folding and related simplification of EXPR.
12827 The related simplifications include x*1 => x, x*0 => 0, etc.,
12828 and application of the associative law.
12829 NOP_EXPR conversions may be removed freely (as long as we
12830 are careful not to change the type of the overall expression).
12831 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
12832 but we can constant-fold them if they have constant operands. */
12834 #ifdef ENABLE_FOLD_CHECKING
12835 # define fold(x) fold_1 (x)
12837 static
12838 #endif
12839 tree
12841 {
12845 tree tem;
12848 /* Return right away if a constant. */
12852 /* CALL_EXPR-like objects with variable numbers of operands are
12853 treated specially. */
12855 {
12857 {
12860 }
12862 }
12865 {
12870 {
12888 }
12889 }
12892 {
12894 {
12901 {
12906 }
12909 }
12911 /* Return a VECTOR_CST if possible. */
12913 {
12919 tree val;
12925 }
12933 }
12935 #ifdef ENABLE_FOLD_CHECKING
12936 #undef fold
12943 /* When --enable-checking=fold, compute a digest of expr before
12944 and after actual fold call to see if fold did not accidentally
12945 change original expr. */
12947 tree
12949 {
12950 tree ret;
12970 }
12972 void
12974 {
12985 }
12987 static void
12989 {
12991 }
12993 static void
12996 {
13002 recursive_label:
13012 {
13013 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13021 }
13029 {
13030 /* Allow these fields to be modified. */
13031 tree tmp;
13042 {
13045 }
13046 }
13048 {
13049 /* Allow TREE_NO_WARNING to be set. Perhaps we shouldn't allow that
13050 and change builtins.c etc. instead - see PR89543. */
13056 }
13067 {
13070 {
13086 }
13090 {
13103 }
13120 {
13126 }
13129 {
13131 {
13134 }
13136 }
13147 {
13150 }
13160 }
13161 }
13163 /* Helper function for outputting the checksum of a tree T. When
13164 debugging with gdb, you can "define mynext" to be "next" followed
13165 by "call debug_fold_checksum (op0)", then just trace down till the
13166 outputs differ. */
13168 DEBUG_FUNCTION void
13170 {
13185 }
13187 #endif
13189 /* Fold a unary tree expression with code CODE of type TYPE with an
13190 operand OP0. LOC is the location of the resulting expression.
13191 Return a folded expression if successful. Otherwise, return a tree
13192 expression with code CODE of type TYPE with an operand OP0. */
13194 tree
13197 {
13198 tree tem;
13199 #ifdef ENABLE_FOLD_CHECKING
13208 #endif
13214 #ifdef ENABLE_FOLD_CHECKING
13221 #endif
13223 }
13225 /* Fold a binary tree expression with code CODE of type TYPE with
13226 operands OP0 and OP1. LOC is the location of the resulting
13227 expression. Return a folded expression if successful. Otherwise,
13228 return a tree expression with code CODE of type TYPE with operands
13229 OP0 and OP1. */
13231 tree
13234 MEM_STAT_DECL)
13235 {
13236 tree tem;
13237 #ifdef ENABLE_FOLD_CHECKING
13254 #endif
13260 #ifdef ENABLE_FOLD_CHECKING
13275 #endif
13277 }
13279 /* Fold a ternary tree expression with code CODE of type TYPE with
13280 operands OP0, OP1, and OP2. Return a folded expression if
13281 successful. Otherwise, return a tree expression with code CODE of
13282 type TYPE with operands OP0, OP1, and OP2. */
13284 tree
13287 {
13288 tree tem;
13289 #ifdef ENABLE_FOLD_CHECKING
13313 #endif
13320 #ifdef ENABLE_FOLD_CHECKING
13343 #endif
13345 }
13347 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13348 arguments in ARGARRAY, and a null static chain.
13349 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13350 of type TYPE from the given operands as constructed by build_call_array. */
13352 tree
13355 {
13356 tree tem;
13357 #ifdef ENABLE_FOLD_CHECKING
13376 #endif
13382 #ifdef ENABLE_FOLD_CHECKING
13398 #endif
13400 }
13402 /* Perform constant folding and related simplification of initializer
13403 expression EXPR. These behave identically to "fold_buildN" but ignore
13404 potential run-time traps and exceptions that fold must preserve. */
13406 #define START_FOLD_INIT \
13407 int saved_signaling_nans = flag_signaling_nans;\
13408 int saved_trapping_math = flag_trapping_math;\
13409 int saved_rounding_math = flag_rounding_math;\
13410 int saved_trapv = flag_trapv;\
13411 int saved_folding_initializer = folding_initializer;\
13412 flag_signaling_nans = 0;\
13413 flag_trapping_math = 0;\
13414 flag_rounding_math = 0;\
13415 flag_trapv = 0;\
13416 folding_initializer = 1;
13418 #define END_FOLD_INIT \
13419 flag_signaling_nans = saved_signaling_nans;\
13420 flag_trapping_math = saved_trapping_math;\
13421 flag_rounding_math = saved_rounding_math;\
13422 flag_trapv = saved_trapv;\
13423 folding_initializer = saved_folding_initializer;
13425 tree
13428 {
13429 tree result;
13430 START_FOLD_INIT;
13434 END_FOLD_INIT;
13436 }
13438 tree
13441 {
13442 tree result;
13443 START_FOLD_INIT;
13447 END_FOLD_INIT;
13449 }
13451 tree
13454 {
13455 tree result;
13456 START_FOLD_INIT;
13460 END_FOLD_INIT;
13462 }
13464 #undef START_FOLD_INIT
13465 #undef END_FOLD_INIT
13467 /* Determine if first argument is a multiple of second argument. Return 0 if
13468 it is not, or we cannot easily determined it to be.
13470 An example of the sort of thing we care about (at this point; this routine
13471 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13472 fold cases do now) is discovering that
13474 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13476 is a multiple of
13478 SAVE_EXPR (J * 8)
13480 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13482 This code also handles discovering that
13484 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13486 is a multiple of 8 so we don't have to worry about dealing with a
13487 possible remainder.
13489 Note that we *look* inside a SAVE_EXPR only to determine how it was
13490 calculated; it is not safe for fold to do much of anything else with the
13491 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13492 at run time. For example, the latter example above *cannot* be implemented
13493 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13494 evaluation time of the original SAVE_EXPR is not necessarily the same at
13495 the time the new expression is evaluated. The only optimization of this
13496 sort that would be valid is changing
13498 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13500 divided by 8 to
13502 SAVE_EXPR (I) * SAVE_EXPR (J)
13504 (where the same SAVE_EXPR (J) is used in the original and the
13505 transformed version). */
13507 int
13509 {
13520 {
13522 /* Bitwise and provides a power of two multiple. If the mask is
13523 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13531 {
13537 {
13540 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
13542 {
13546 {
13549 }
13550 }
13552 }
13553 }
13558 /* It is impossible to prove if op0 - op1 is multiple of bottom
13559 precisely, so be conservative here checking if both op0 and op1
13560 are multiple of bottom. Note we check the second operand first
13561 since it's usually simpler. */
13566 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
13567 as op0 - 3 if the expression has unsigned type. For example,
13568 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
13578 {
13580 /* const_binop may not detect overflow correctly,
13581 so check for it explicitly here. */
13589 }
13593 /* Can't handle conversions from non-integral or wider integral type. */
13599 /* fall through */
13616 SIGNED);
13622 {
13625 /* Check for special cases to see if top is defined as multiple
13626 of bottom:
13628 top = (X & ~(bottom - 1) ; bottom is power of 2
13630 or
13632 Y = X % bottom
13633 top = X - Y. */
13652 }
13654 /* fall through */
13662 }
13663 }
13665 #define tree_expr_nonnegative_warnv_p(X, Y) \
13668 #define RECURSE(X) \
13669 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
13671 /* Return true if CODE or TYPE is known to be non-negative. */
13673 static bool
13675 {
13678 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
13679 have a signed:1 type (where the value is -1 and 0). */
13682 }
13684 /* Return true if (CODE OP0) is known to be non-negative. If the return
13685 value is based on the assumption that signed overflow is undefined,
13686 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13687 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13689 bool
13692 {
13697 {
13699 /* We can't return 1 if flag_wrapv is set because
13700 ABS_EXPR<INT_MIN> = INT_MIN. */
13704 {
13707 }
13715 CASE_CONVERT:
13716 {
13721 {
13725 {
13729 }
13730 }
13732 {
13738 }
13739 }
13744 }
13746 /* We don't know sign of `t', so be conservative and return false. */
13748 }
13750 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
13751 value is based on the assumption that signed overflow is undefined,
13752 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13753 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13755 bool
13759 {
13764 {
13770 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
13771 both unsigned and at least 2 bits shorter than the result. */
13775 {
13780 {
13784 }
13785 }
13790 {
13791 /* x * x is always non-negative for floating point x
13792 or without overflow. */
13795 {
13800 }
13801 }
13803 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
13804 both unsigned and their total bits is shorter than the result. */
13808 {
13827 {
13837 }
13838 }
13865 }
13867 /* We don't know sign of `t', so be conservative and return false. */
13869 }
13871 /* Return true if T is known to be non-negative. If the return
13872 value is based on the assumption that signed overflow is undefined,
13873 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13874 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13876 bool
13878 {
13883 {
13897 /* Limit the depth of recursion to avoid quadratic behavior.
13898 This is expected to catch almost all occurrences in practice.
13899 If this code misses important cases that unbounded recursion
13900 would not, passes that need this information could be revised
13901 to provide it through dataflow propagation. */
13909 }
13910 }
13912 /* Return true if T is known to be non-negative. If the return
13913 value is based on the assumption that signed overflow is undefined,
13914 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13915 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13917 bool
13920 {
13922 {
13923 CASE_CFN_ACOS:
13924 CASE_CFN_ACOSH:
13925 CASE_CFN_CABS:
13926 CASE_CFN_COSH:
13927 CASE_CFN_ERFC:
13928 CASE_CFN_EXP:
13929 CASE_CFN_EXP10:
13930 CASE_CFN_EXP2:
13931 CASE_CFN_FABS:
13932 CASE_CFN_FDIM:
13933 CASE_CFN_HYPOT:
13934 CASE_CFN_POW10:
13935 CASE_CFN_FFS:
13936 CASE_CFN_PARITY:
13937 CASE_CFN_POPCOUNT:
13938 CASE_CFN_CLZ:
13939 CASE_CFN_CLRSB:
13944 /* Always true. */
13947 CASE_CFN_SQRT:
13948 CASE_CFN_SQRT_FN:
13949 /* sqrt(-0.0) is -0.0. */
13954 CASE_CFN_ASINH:
13955 CASE_CFN_ATAN:
13956 CASE_CFN_ATANH:
13957 CASE_CFN_CBRT:
13958 CASE_CFN_CEIL:
13959 CASE_CFN_CEIL_FN:
13960 CASE_CFN_ERF:
13961 CASE_CFN_EXPM1:
13962 CASE_CFN_FLOOR:
13963 CASE_CFN_FLOOR_FN:
13964 CASE_CFN_FMOD:
13965 CASE_CFN_FREXP:
13966 CASE_CFN_ICEIL:
13967 CASE_CFN_IFLOOR:
13968 CASE_CFN_IRINT:
13969 CASE_CFN_IROUND:
13970 CASE_CFN_LCEIL:
13971 CASE_CFN_LDEXP:
13972 CASE_CFN_LFLOOR:
13973 CASE_CFN_LLCEIL:
13974 CASE_CFN_LLFLOOR:
13975 CASE_CFN_LLRINT:
13976 CASE_CFN_LLROUND:
13977 CASE_CFN_LRINT:
13978 CASE_CFN_LROUND:
13979 CASE_CFN_MODF:
13980 CASE_CFN_NEARBYINT:
13981 CASE_CFN_NEARBYINT_FN:
13982 CASE_CFN_RINT:
13983 CASE_CFN_RINT_FN:
13984 CASE_CFN_ROUND:
13985 CASE_CFN_ROUND_FN:
13986 CASE_CFN_ROUNDEVEN:
13987 CASE_CFN_ROUNDEVEN_FN:
13988 CASE_CFN_SCALB:
13989 CASE_CFN_SCALBLN:
13990 CASE_CFN_SCALBN:
13991 CASE_CFN_SIGNBIT:
13992 CASE_CFN_SIGNIFICAND:
13993 CASE_CFN_SINH:
13994 CASE_CFN_TANH:
13995 CASE_CFN_TRUNC:
13996 CASE_CFN_TRUNC_FN:
13997 /* True if the 1st argument is nonnegative. */
14000 CASE_CFN_FMAX:
14001 CASE_CFN_FMAX_FN:
14002 /* True if the 1st OR 2nd arguments are nonnegative. */
14005 CASE_CFN_FMIN:
14006 CASE_CFN_FMIN_FN:
14007 /* True if the 1st AND 2nd arguments are nonnegative. */
14010 CASE_CFN_COPYSIGN:
14011 CASE_CFN_COPYSIGN_FN:
14012 /* True if the 2nd argument is nonnegative. */
14015 CASE_CFN_POWI:
14016 /* True if the 1st argument is nonnegative or the second
14017 argument is an even integer. */
14023 CASE_CFN_POW:
14024 /* True if the 1st argument is nonnegative or the second
14025 argument is an even integer valued real. */
14027 {
14028 REAL_VALUE_TYPE c;
14029 HOST_WIDE_INT n;
14034 {
14035 REAL_VALUE_TYPE cint;
14039 }
14040 }
14045 }
14047 }
14049 /* Return true if T is known to be non-negative. If the return
14050 value is based on the assumption that signed overflow is undefined,
14051 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14052 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14054 static bool
14056 {
14062 {
14064 {
14068 /* If the initializer is non-void, then it's a normal expression
14069 that will be assigned to the slot. */
14073 /* Otherwise, the initializer sets the slot in some way. One common
14074 way is an assignment statement at the end of the initializer. */
14076 {
14084 else
14086 }
14092 }
14095 {
14101 arg0,
14102 arg1,
14104 }
14117 }
14118 }
14120 #undef RECURSE
14121 #undef tree_expr_nonnegative_warnv_p
14123 /* Return true if T is known to be non-negative. If the return
14124 value is based on the assumption that signed overflow is undefined,
14125 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14126 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14128 bool
14130 {
14137 {
14159 }
14162 {
14188 }
14189 }
14191 /* Return true if `t' is known to be non-negative. Handle warnings
14192 about undefined signed overflow. */
14194 bool
14196 {
14203 "determining that expression is always "
14205 WARN_STRICT_OVERFLOW_MISC);
14207 }
14210 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14211 For floating point we further ensure that T is not denormal.
14212 Similar logic is present in nonzero_address in rtlanal.h.
14214 If the return value is based on the assumption that signed overflow
14215 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14216 change *STRICT_OVERFLOW_P. */
14218 bool
14221 {
14223 {
14226 strict_overflow_p);
14229 {
14235 strict_overflow_p));
14236 }
14241 strict_overflow_p);
14245 }
14248 }
14250 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14251 For floating point we further ensure that T is not denormal.
14252 Similar logic is present in nonzero_address in rtlanal.h.
14254 If the return value is based on the assumption that signed overflow
14255 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14256 change *STRICT_OVERFLOW_P. */
14258 bool
14260 tree type,
14261 tree op0,
14263 {
14266 {
14270 {
14271 /* With the presence of negative values it is hard
14272 to say something. */
14279 /* One of operands must be positive and the other non-negative. */
14280 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14281 overflows, on a twos-complement machine the sum of two
14282 nonnegative numbers can never be zero. */
14284 strict_overflow_p)
14286 strict_overflow_p));
14287 }
14292 {
14294 strict_overflow_p)
14296 strict_overflow_p))
14297 {
14300 }
14301 }
14310 {
14313 }
14320 {
14324 /* When both operands are nonzero, then MAX must be too. */
14326 strict_overflow_p))
14329 /* MAX where operand 0 is positive is positive. */
14331 strict_overflow_p);
14332 }
14333 /* MAX where operand 1 is positive is positive. */
14338 {
14342 }
14347 strict_overflow_p)
14349 strict_overflow_p));
14353 }
14356 }
14358 /* Return true when T is an address and is known to be nonzero.
14359 For floating point we further ensure that T is not denormal.
14360 Similar logic is present in nonzero_address in rtlanal.h.
14362 If the return value is based on the assumption that signed overflow
14363 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14364 change *STRICT_OVERFLOW_P. */
14366 bool
14368 {
14371 {
14376 {
14388 /* For objects in symbol table check if we know they are non-zero.
14389 Don't do anything for variables and functions before symtab is built;
14390 it is quite possible that they will be declared weak later. */
14395 /* Constants are never weak. */
14400 }
14408 {
14412 }
14422 }
14424 }
14426 #define integer_valued_real_p(X) \
14429 #define RECURSE(X) \
14430 ((integer_valued_real_p) (X, depth + 1))
14432 /* Return true if the floating point result of (CODE OP0) has an
14433 integer value. We also allow +Inf, -Inf and NaN to be considered
14434 integer values. Return false for signaling NaN.
14436 DEPTH is the current nesting depth of the query. */
14438 bool
14440 {
14442 {
14449 CASE_CONVERT:
14450 {
14457 }
14461 }
14463 }
14465 /* Return true if the floating point result of (CODE OP0 OP1) has an
14466 integer value. We also allow +Inf, -Inf and NaN to be considered
14467 integer values. Return false for signaling NaN.
14469 DEPTH is the current nesting depth of the query. */
14471 bool
14473 {
14475 {
14485 }
14487 }
14489 /* Return true if the floating point result of calling FNDECL with arguments
14490 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
14491 considered integer values. Return false for signaling NaN. If FNDECL
14492 takes fewer than 2 arguments, the remaining ARGn are null.
14494 DEPTH is the current nesting depth of the query. */
14496 bool
14498 {
14500 {
14501 CASE_CFN_CEIL:
14502 CASE_CFN_CEIL_FN:
14503 CASE_CFN_FLOOR:
14504 CASE_CFN_FLOOR_FN:
14505 CASE_CFN_NEARBYINT:
14506 CASE_CFN_NEARBYINT_FN:
14507 CASE_CFN_RINT:
14508 CASE_CFN_RINT_FN:
14509 CASE_CFN_ROUND:
14510 CASE_CFN_ROUND_FN:
14511 CASE_CFN_ROUNDEVEN:
14512 CASE_CFN_ROUNDEVEN_FN:
14513 CASE_CFN_TRUNC:
14514 CASE_CFN_TRUNC_FN:
14517 CASE_CFN_FMIN:
14518 CASE_CFN_FMIN_FN:
14519 CASE_CFN_FMAX:
14520 CASE_CFN_FMAX_FN:
14525 }
14527 }
14529 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
14530 has an integer value. We also allow +Inf, -Inf and NaN to be
14531 considered integer values. Return false for signaling NaN.
14533 DEPTH is the current nesting depth of the query. */
14535 bool
14537 {
14539 {
14547 /* Limit the depth of recursion to avoid quadratic behavior.
14548 This is expected to catch almost all occurrences in practice.
14549 If this code misses important cases that unbounded recursion
14550 would not, passes that need this information could be revised
14551 to provide it through dataflow propagation. */
14555 depth));
14559 }
14561 }
14563 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
14564 has an integer value. We also allow +Inf, -Inf and NaN to be
14565 considered integer values. Return false for signaling NaN.
14567 DEPTH is the current nesting depth of the query. */
14569 static bool
14571 {
14573 {
14584 }
14586 }
14588 #undef RECURSE
14589 #undef integer_valued_real_p
14591 /* Return true if the floating point expression T has an integer value.
14592 We also allow +Inf, -Inf and NaN to be considered integer values.
14593 Return false for signaling NaN.
14595 DEPTH is the current nesting depth of the query. */
14597 bool
14599 {
14607 {
14623 }
14626 {
14632 {
14641 }
14645 }
14646 }
14648 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
14649 attempt to fold the expression to a constant without modifying TYPE,
14650 OP0 or OP1.
14652 If the expression could be simplified to a constant, then return
14653 the constant. If the expression would not be simplified to a
14654 constant, then return NULL_TREE. */
14656 tree
14658 {
14661 }
14663 /* Given the components of a unary expression CODE, TYPE and OP0,
14664 attempt to fold the expression to a constant without modifying
14665 TYPE or OP0.
14667 If the expression could be simplified to a constant, then return
14668 the constant. If the expression would not be simplified to a
14669 constant, then return NULL_TREE. */
14671 tree
14673 {
14676 }
14678 /* If EXP represents referencing an element in a constant string
14679 (either via pointer arithmetic or array indexing), return the
14680 tree representing the value accessed, otherwise return NULL. */
14682 tree
14684 {
14688 {
14690 tree index;
14691 tree string;
14696 else
14697 {
14701 /* Optimize the special-case of a zero lower bound.
14703 We convert the low_bound to sizetype to avoid some problems
14704 with constant folding. (E.g. suppose the lower bound is 1,
14705 and its mode is QI. Without the conversion,l (ARRAY
14706 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
14707 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
14713 }
14715 scalar_int_mode char_mode;
14727 }
14729 }
14731 /* Folds a read from vector element at IDX of vector ARG. */
14733 tree
14735 {
14740 {
14744 {
14748 }
14749 }
14751 }
14753 /* Return the tree for neg (ARG0) when ARG0 is known to be either
14754 an integer constant, real, or fixed-point constant.
14756 TYPE is the type of the result. */
14758 static tree
14760 {
14764 {
14770 {
14771 FIXED_VALUE_TYPE f;
14776 /* Propagate overflow flags. */
14780 }
14784 {
14791 }
14794 }
14797 }
14799 /* Return the tree for abs (ARG0) when ARG0 is known to be either
14800 an integer constant or real constant.
14802 TYPE is the type of the result. */
14804 tree
14806 {
14810 {
14812 {
14813 /* If the value is unsigned or non-negative, then the absolute value
14814 is the same as the ordinary value. */
14818 ;
14820 /* If the value is negative, then the absolute value is
14821 its negation. */
14822 else
14825 /* Force to the destination type, set TREE_OVERFLOW for signed
14826 TYPE only. */
14828 }
14834 else
14840 }
14843 }
14845 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
14846 constant. TYPE is the type of the result. */
14848 static tree
14850 {
14854 }
14856 /* Given CODE, a relational operator, the target type, TYPE and two
14857 constant operands OP0 and OP1, return the result of the
14858 relational operation. If the result is not a compile time
14859 constant, then return NULL_TREE. */
14861 static tree
14863 {
14866 /* From here on, the only cases we handle are when the result is
14867 known to be a constant. */
14870 {
14874 /* Handle the cases where either operand is a NaN. */
14876 {
14878 {
14906 }
14909 }
14912 }
14915 {
14919 }
14921 /* Handle equality/inequality of complex constants. */
14923 {
14934 else
14936 }
14939 {
14941 {
14942 /* Have vector comparison with scalar boolean result. */
14950 {
14958 }
14960 }
14961 tree_vector_builder elts;
14966 {
14979 }
14982 }
14984 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
14986 To compute GT, swap the arguments and do LT.
14987 To compute GE, do LT and invert the result.
14988 To compute LE, swap the arguments, do LT and invert the result.
14989 To compute NE, do EQ and invert the result.
14991 Therefore, the code below must handle only EQ and LT. */
14994 {
14997 }
14999 /* Note that it is safe to invert for real values here because we
15000 have already handled the one case that it matters. */
15004 {
15007 }
15009 /* Compute a result for LT or EQ if args permit;
15010 Otherwise return T. */
15012 {
15015 else
15017 }
15018 else
15024 }
15026 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15027 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15028 itself. */
15030 tree
15032 {
15033 /* If the expression does not have side effects then we don't have to wrap
15034 it with a cleanup point expression. */
15038 /* If the expression is a return, check to see if the expression inside the
15039 return has no side effects or the right hand side of the modify expression
15040 inside the return. If either don't have side effects set we don't need to
15041 wrap the expression in a cleanup point expression. Note we don't check the
15042 left hand side of the modify because it should always be a return decl. */
15044 {
15051 }
15054 }
15056 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15057 of an indirection through OP0, or NULL_TREE if no simplification is
15058 possible. */
15060 tree
15062 {
15064 tree subtype;
15065 poly_uint64 const_op01;
15074 {
15078 /* *&CONST_DECL -> to the value of the const decl. */
15081 /* *&p => p; make sure to handle *&"str"[cst] here. */
15083 {
15087 else
15089 }
15090 /* *(foo *)&fooarray => fooarray[0] */
15093 && (!in_gimple_form
15095 {
15105 }
15106 /* *(foo *)&complexfoo => __real__ complexfoo */
15110 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15113 {
15117 index);
15118 }
15119 }
15123 {
15129 {
15130 tree op00type;
15134 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15137 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
15138 but we want to treat offsets with MSB set as negative.
15139 For the code below negative offsets are invalid and
15140 TYPE_SIZE of the element is something unsigned, so
15141 check whether op01 fits into poly_int64, which implies
15142 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
15143 then just use poly_uint64 because we want to treat the
15144 value as unsigned. */
15146 {
15148 poly_uint64 max_offset
15152 {
15157 }
15158 }
15159 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15162 {
15164 const_op01))
15166 }
15167 /* ((foo *)&fooarray)[1] => fooarray[1] */
15170 {
15179 {
15184 }
15185 }
15186 }
15187 }
15189 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15192 && (!in_gimple_form
15194 {
15195 tree type_domain;
15205 NULL_TREE);
15206 }
15209 }
15211 /* Builds an expression for an indirection through T, simplifying some
15212 cases. */
15214 tree
15216 {
15224 }
15226 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15228 tree
15230 {
15235 else
15237 }
15239 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15240 whose result is ignored. The type of the returned tree need not be
15241 the same as the original expression. */
15243 tree
15245 {
15251 {
15262 else
15268 {
15284 }
15289 }
15290 }
15292 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
15294 tree
15296 {
15302 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15303 have to do anything. Only do this when we are not given a const,
15304 because in that case, this check is more expensive than just
15305 doing it. */
15307 {
15312 }
15314 /* If divisor is a power of two, simplify this to bit manipulation. */
15316 {
15318 {
15332 }
15333 else
15334 {
15335 tree t;
15341 }
15342 }
15343 else
15344 {
15349 }
15352 }
15354 /* Likewise, but round down. */
15356 tree
15358 {
15365 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15366 have to do anything. Only do this when we are not given a const,
15367 because in that case, this check is more expensive than just
15368 doing it. */
15370 {
15375 }
15377 /* If divisor is a power of two, simplify this to bit manipulation. */
15379 {
15380 tree t;
15384 }
15385 else
15386 {
15391 }
15394 }
15396 /* Returns the pointer to the base of the object addressed by EXP and
15397 extracts the information about the offset of the access, storing it
15398 to PBITPOS and POFFSET. */
15400 static tree
15403 {
15404 tree core;
15405 machine_mode mode;
15407 poly_int64 bitsize;
15411 {
15416 }
15418 {
15424 {
15425 poly_offset_int tem
15431 }
15432 }
15433 else
15434 {
15438 }
15441 }
15443 /* Returns true if addresses of E1 and E2 differ by a constant, false
15444 otherwise. If they do, E1 - E2 is stored in *DIFF. */
15446 bool
15448 {
15463 {
15473 }
15475 {
15476 /* If only one of the offsets is non-constant, the difference cannot
15477 be a constant. */
15479 }
15480 else
15485 }
15487 /* Return OFF converted to a pointer offset type suitable as offset for
15488 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
15489 tree
15491 {
15495 }
15497 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15498 tree
15500 {
15503 }
15505 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
15506 tree
15508 {
15511 }
15513 /* Return a pointer to a NUL-terminated string containing the sequence
15514 of bytes corresponding to the representation of the object referred to
15515 by SRC (or a subsequence of such bytes within it if SRC is a reference
15516 to an initialized constant array plus some constant offset).
15517 Set *STRSIZE the number of bytes in the constant sequence including
15518 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
15519 where A is the array that stores the constant sequence that SRC points
15520 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
15521 need not point to a string or even an array of characters but may point
15522 to an object of any type. */
15526 {
15527 /* The offset into the array A storing the string, and A's byte size. */
15528 tree offset_node;
15529 tree mem_size;
15536 else
15543 {
15546 else
15548 }
15553 /* ARRAY_SIZE is the byte size of the array the constant sequence
15554 is stored in and equal to sizeof A. INIT_BYTES is the number
15555 of bytes in the constant sequence used to initialize the array,
15556 including any embedded NULs as well as the terminating NUL (for
15557 strings), but not including any trailing zeros/NULs past
15558 the terminating one appended implicitly to a string literal to
15559 zero out the remainder of the array it's stored in. For example,
15560 given:
15561 const char a[7] = "abc\0d";
15562 n = strlen (a + 1);
15563 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
15564 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
15565 is equal to strlen (A) + 1. */
15569 /* Ideally this would turn into a gcc_checking_assert over time. */
15575 /* Ideally this would turn into a gcc_checking_assert over time. */
15583 {
15584 /* Compute and store the number of characters from the beginning
15585 of the substring at OFFSET to the end, including the terminating
15586 nul. Offsets past the initial length refer to null strings. */
15589 else
15591 }
15592 else
15593 {
15595 /* Support only properly NUL-terminated single byte strings. */
15600 }
15603 }
15605 /* Return a pointer to a NUL-terminated string corresponding to
15606 the expression STR referencing a constant string, possibly
15607 involving a constant offset. Return null if STR either doesn't
15608 reference a constant string or if it involves a nonconstant
15609 offset. */
15613 {
15615 }
15617 /* Given a tree T, compute which bits in T may be nonzero. */
15619 wide_int
15621 {
15623 {
15641 CASE_CONVERT:
15647 {
15652 }
15656 {
15664 }
15668 {
15676 }
15680 }
15683 }
15685 #if CHECKING_P
15689 /* Helper functions for writing tests of folding trees. */
15691 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
15693 static void
15695 tree constant)
15696 {
15698 }
15700 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
15701 wrapping WRAPPED_EXPR. */
15703 static void
15705 tree wrapped_expr)
15706 {
15711 }
15713 /* Verify that various arithmetic binary operations are folded
15714 correctly. */
15716 static void
15718 {
15724 /* Addition. */
15725 /* 1 <-- (0 + 1) */
15727 one);
15729 one);
15731 /* (nonlvalue)x <-- (x + 0) */
15733 x);
15735 /* Subtraction. */
15736 /* 0 <-- (x - x) */
15738 zero);
15740 x);
15742 /* Multiplication. */
15743 /* 0 <-- (x * 0) */
15745 zero);
15747 /* (nonlvalue)x <-- (x * 1) */
15749 x);
15750 }
15752 /* Verify that various binary operations on vectors are folded
15753 correctly. */
15755 static void
15757 {
15764 /* Verify equality tests that return a scalar boolean result. */
15777 }
15779 /* Verify folding of VEC_DUPLICATE_EXPRs. */
15781 static void
15783 {
15786 /* This will be 1 if VEC_MODE isn't a vector mode. */
15793 }
15795 /* Run all of the selftests within this file. */
15797 void
15799 {
15803 }