| blob | ff23f12f33c9e06071eca2b7664d82ef44210dd7 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2021 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. */
88 /* Nonzero if we are folding constants inside an initializer; zero
89 otherwise. */
92 /* The following constants represent a bit based encoding of GCC's
93 comparison operators. This encoding simplifies transformations
94 on relational comparison operators, such as AND and OR. */
112 };
146 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
147 Otherwise, return LOC. */
149 static location_t
151 {
154 }
156 /* Similar to protected_set_expr_location, but never modify x in place,
157 if location can and needs to be set, unshare it. */
161 {
167 {
170 }
172 }
173 \f
174 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
175 division and returns the quotient. Otherwise returns
176 NULL_TREE. */
178 tree
180 {
181 widest_int quo;
188 }
189 \f
190 /* This is nonzero if we should defer warnings about undefined
191 overflow. This facility exists because these warnings are a
192 special case. The code to estimate loop iterations does not want
193 to issue any warnings, since it works with expressions which do not
194 occur in user code. Various bits of cleanup code call fold(), but
195 only use the result if it has certain characteristics (e.g., is a
196 constant); that code only wants to issue a warning if the result is
197 used. */
201 /* If a warning about undefined overflow is deferred, this is the
202 warning. Note that this may cause us to turn two warnings into
203 one, but that is fine since it is sufficient to only give one
204 warning per expression. */
208 /* If a warning about undefined overflow is deferred, this is the
209 level at which the warning should be emitted. */
213 /* Start deferring overflow warnings. We could use a stack here to
214 permit nested calls, but at present it is not necessary. */
216 void
218 {
220 }
222 /* Stop deferring overflow warnings. If there is a pending warning,
223 and ISSUE is true, then issue the warning if appropriate. STMT is
224 the statement with which the warning should be associated (used for
225 location information); STMT may be NULL. CODE is the level of the
226 warning--a warn_strict_overflow_code value. This function will use
227 the smaller of CODE and the deferred code when deciding whether to
228 issue the warning. CODE may be zero to mean to always use the
229 deferred code. */
231 void
233 {
235 location_t locus;
240 {
246 }
257 /* Use the smallest code level when deciding to issue the
258 warning. */
267 else
270 }
272 /* Stop deferring overflow warnings, ignoring any deferred
273 warnings. */
275 void
277 {
279 }
281 /* Whether we are deferring overflow warnings. */
283 bool
285 {
287 }
289 /* This is called when we fold something based on the fact that signed
290 overflow is undefined. */
292 void
294 {
296 {
299 {
302 }
303 }
306 }
307 \f
308 /* Return true if the built-in mathematical function specified by CODE
309 is odd, i.e. -f(x) == f(-x). */
311 bool
313 {
315 {
316 CASE_CFN_ASIN:
317 CASE_CFN_ASINH:
318 CASE_CFN_ATAN:
319 CASE_CFN_ATANH:
320 CASE_CFN_CASIN:
321 CASE_CFN_CASINH:
322 CASE_CFN_CATAN:
323 CASE_CFN_CATANH:
324 CASE_CFN_CBRT:
325 CASE_CFN_CPROJ:
326 CASE_CFN_CSIN:
327 CASE_CFN_CSINH:
328 CASE_CFN_CTAN:
329 CASE_CFN_CTANH:
330 CASE_CFN_ERF:
331 CASE_CFN_LLROUND:
332 CASE_CFN_LROUND:
333 CASE_CFN_ROUND:
334 CASE_CFN_ROUNDEVEN:
335 CASE_CFN_ROUNDEVEN_FN:
336 CASE_CFN_SIN:
337 CASE_CFN_SINH:
338 CASE_CFN_TAN:
339 CASE_CFN_TANH:
340 CASE_CFN_TRUNC:
343 CASE_CFN_LLRINT:
344 CASE_CFN_LRINT:
345 CASE_CFN_NEARBYINT:
346 CASE_CFN_RINT:
351 }
353 }
355 /* Check whether we may negate an integer constant T without causing
356 overflow. */
358 bool
360 {
361 tree type;
370 }
372 /* Determine whether an expression T can be cheaply negated using
373 the function negate_expr without introducing undefined overflow. */
375 static bool
377 {
378 tree type;
387 {
392 /* Check that -CST will not overflow type. */
405 /* We want to canonicalize to positive real constants. Pretend
406 that only negative ones can be easily negated. */
414 {
418 /* Steps don't prevent negation. */
425 }
440 /* -(A + B) -> (-B) - A. */
443 /* -(A + B) -> (-A) - B. */
447 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
456 /* INT_MIN/n * n doesn't overflow while negating one operand it does
457 if n is a (negative) power of two. */
468 /* Fall through. */
481 /* In general we can't negate A in A / B, because if A is INT_MIN and
482 B is not 1 we change the sign of the result. */
486 /* In general we can't negate B in A / B, because if A is INT_MIN and
487 B is 1, we may turn this into INT_MIN / -1 which is undefined
488 and actually traps on some architectures. */
497 /* Negate -((double)float) as (double)(-float). */
499 {
503 }
507 /* Negate -f(x) as f(-x). */
513 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
515 {
519 }
524 }
526 }
528 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
529 simplification is possible.
530 If negate_expr_p would return true for T, NULL_TREE will never be
531 returned. */
533 static tree
535 {
537 tree tem;
540 {
541 /* Convert - (~A) to A + 1. */
565 {
570 }
574 {
575 tree_vector_builder elts;
579 {
584 }
587 }
610 {
611 /* -(A + B) -> (-B) - A. */
613 {
617 }
619 /* -(A + B) -> (-A) - B. */
621 {
625 }
626 }
630 /* - (A - B) -> B - A */
641 /* Fall through. */
645 {
654 }
662 /* In general we can't negate A in A / B, because if A is INT_MIN and
663 B is not 1 we change the sign of the result. */
669 /* In general we can't negate B in A / B, because if A is INT_MIN and
670 B is 1, we may turn this into INT_MIN / -1 which is undefined
671 and actually traps on some architectures. */
683 /* Convert -((double)float) into (double)(-float). */
685 {
689 }
693 /* Negate -f(x) as f(-x). */
696 {
702 }
706 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
708 {
711 {
718 }
719 }
724 }
727 }
729 /* A wrapper for fold_negate_expr_1. */
731 static tree
733 {
740 }
742 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
743 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
744 return NULL_TREE. */
746 static tree
748 {
750 location_t loc;
763 }
764 \f
765 /* Split a tree IN into a constant, literal and variable parts that could be
766 combined with CODE to make IN. "constant" means an expression with
767 TREE_CONSTANT but that isn't an actual constant. CODE must be a
768 commutative arithmetic operation. Store the constant part into *CONP,
769 the literal in *LITP and return the variable part. If a part isn't
770 present, set it to null. If the tree does not decompose in this way,
771 return the entire tree as the variable part and the other parts as null.
773 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
774 case, we negate an operand that was subtracted. Except if it is a
775 literal for which we use *MINUS_LITP instead.
777 If NEGATE_P is true, we are negating all of IN, again except a literal
778 for which we use *MINUS_LITP instead. If a variable part is of pointer
779 type, it is negated after converting to TYPE. This prevents us from
780 generating illegal MINUS pointer expression. LOC is the location of
781 the converted variable part.
783 If IN is itself a literal or constant, return it as appropriate.
785 Note that we do not guarantee that any of the three values will be the
786 same type as IN, but they will have the same signedness and mode. */
788 static tree
792 {
800 /* Strip any conversions that don't change the machine mode or signedness. */
809 /* We can associate addition and subtraction together (even
810 though the C standard doesn't say so) for integers because
811 the value is not affected. For reals, the value might be
812 affected, so we can't. */
818 {
824 /* First see if either of the operands is a literal, then a constant. */
837 /* If we haven't dealt with either operand, this is not a case we can
838 decompose. Otherwise, VAR is either of the ones remaining, if any. */
843 else
846 /* Now do any needed negations. */
853 }
858 {
859 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
860 when IN is constant. */
863 }
864 else
868 {
881 }
891 }
893 /* Re-associate trees split by the above function. T1 and T2 are
894 either expressions to associate or null. Return the new
895 expression, if any. LOC is the location of the new expression. If
896 we build an operation, do it in TYPE and with CODE. */
898 static tree
900 {
902 {
905 }
909 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
910 try to fold this since we will have infinite recursion. But do
911 deal with any NEGATE_EXPRs. */
915 {
917 {
930 }
932 {
935 }
939 }
943 }
944 \f
945 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
946 for use in int_const_binop, size_binop and size_diffop. */
948 static bool
950 {
957 {
966 }
971 }
973 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
974 a new constant in RES. Return FALSE if we don't know how to
975 evaluate CODE at compile-time. */
977 bool
981 {
982 wide_int tmp;
985 {
1007 /* It's unclear from the C standard whether shifts can overflow.
1008 The following code ignores overflow; perhaps a C standard
1009 interpretation ruling is needed. */
1016 {
1020 else
1022 }
1023 else
1028 else
1107 }
1109 }
1111 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1112 produce a new constant in RES. Return FALSE if we don't know how
1113 to evaluate CODE at compile-time. */
1115 static bool
1119 {
1123 {
1141 else
1148 else
1161 }
1163 }
1165 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1166 produce a new constant. Return NULL_TREE if we don't know how to
1167 evaluate CODE at compile-time. */
1169 tree
1172 {
1173 poly_wide_int poly_res;
1179 {
1185 }
1194 }
1196 /* Return true if binary operation OP distributes over addition in operand
1197 OPNO, with the other operand being held constant. OPNO counts from 1. */
1199 static bool
1201 {
1203 {
1214 }
1215 }
1217 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1218 constant. We assume ARG1 and ARG2 have the same data type, or at least
1219 are the same kind of constant and the same machine mode. Return zero if
1220 combining the constants is not allowed in the current operating mode. */
1222 static tree
1224 {
1225 /* Sanity check for the recursive cases. */
1233 {
1239 }
1242 {
1243 machine_mode mode;
1244 REAL_VALUE_TYPE d1;
1245 REAL_VALUE_TYPE d2;
1246 REAL_VALUE_TYPE value;
1247 REAL_VALUE_TYPE result;
1251 /* The following codes are handled by real_arithmetic. */
1253 {
1264 }
1272 /* Don't perform operation if we honor signaling NaNs and
1273 either operand is a signaling NaN. */
1279 /* Don't perform operation if it would raise a division
1280 by zero exception. */
1286 /* If either operand is a NaN, just return it. Otherwise, set up
1287 for floating-point trap; we return an overflow. */
1289 {
1290 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1291 is off. */
1295 }
1297 {
1298 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1299 is off. */
1303 }
1308 /* Don't constant fold this floating point operation if
1309 the result has overflowed and flag_trapping_math. */
1317 /* Don't constant fold this floating point operation if the
1318 result may dependent upon the run-time rounding mode and
1319 flag_rounding_math is set, or if GCC's software emulation
1320 is unable to accurately represent the result. */
1330 }
1333 {
1334 FIXED_VALUE_TYPE f1;
1335 FIXED_VALUE_TYPE f2;
1336 FIXED_VALUE_TYPE result;
1341 /* The following codes are handled by fixed_arithmetic. */
1343 {
1355 {
1362 }
1367 }
1374 /* Propagate overflow flags. */
1378 }
1381 {
1390 {
1401 mpc_mul);
1415 mpc_div);
1416 /* Fallthru. */
1422 {
1423 /* Keep this algorithm in sync with
1424 tree-complex.c:expand_complex_div_straight().
1426 Expand complex division to scalars, straightforward algorithm.
1427 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1428 t = br*br + bi*bi
1429 */
1430 tree magsquared
1434 tree t1
1438 tree t2
1445 }
1446 else
1447 {
1448 /* Keep this algorithm in sync with
1449 tree-complex.c:expand_complex_div_wide().
1451 Expand complex division to scalars, modified algorithm to minimize
1452 overflow with wide input ranges. */
1458 {
1459 /* In the TRUE branch, we compute
1460 ratio = br/bi;
1461 div = (br * ratio) + bi;
1462 tr = (ar * ratio) + ai;
1463 ti = (ai * ratio) - ar;
1464 tr = tr / div;
1465 ti = ti / div; */
1476 }
1477 else
1478 {
1479 /* In the FALSE branch, we compute
1480 ratio = d/c;
1481 divisor = (d * ratio) + c;
1482 tr = (b * ratio) + a;
1483 ti = b - (a * ratio);
1484 tr = tr / div;
1485 ti = ti / div; */
1497 }
1498 }
1503 }
1507 }
1513 {
1518 /* We can operate directly on the encoding if:
1520 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1521 implies
1522 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1524 Addition and subtraction are the supported operators
1525 for which this is true. */
1528 /* We can operate directly on stepped encodings if:
1530 a3 - a2 == a2 - a1
1531 implies:
1532 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1534 which is true if (x -> x op c) distributes over addition. */
1536 else
1537 /* Similarly in reverse. */
1539 tree_vector_builder elts;
1544 {
1550 /* It is possible that const_binop cannot handle the given
1551 code and return NULL_TREE */
1555 }
1558 }
1560 /* Shifts allow a scalar offset for a vector. */
1563 {
1566 tree_vector_builder elts;
1571 {
1576 /* It is possible that const_binop cannot handle the given
1577 code and return NULL_TREE. */
1581 }
1584 }
1586 }
1588 /* Overload that adds a TYPE parameter to be able to dispatch
1589 to fold_relational_const. */
1591 tree
1593 {
1597 /* ??? Until we make the const_binop worker take the type of the
1598 result as argument put those cases that need it here. */
1600 {
1617 {
1622 }
1628 {
1644 {
1649 ? NOP_EXPR
1656 }
1659 }
1665 {
1688 {
1701 }
1704 }
1707 }
1712 /* Make sure type and arg0 have the same saturating flag. */
1717 }
1719 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1720 Return zero if computing the constants is not possible. */
1722 tree
1724 {
1725 /* Don't perform the operation, other than NEGATE and ABS, if
1726 flag_signaling_nans is on and the operand is a signaling NaN. */
1736 {
1737 CASE_CONVERT:
1744 /* If the source address is 0, and the source address space
1745 cannot have a valid object at 0, fold to dest type null. */
1756 {
1757 /* Can't call fold_negate_const directly here as that doesn't
1758 handle all cases and we might not be able to negate some
1759 constants. */
1764 }
1774 {
1778 }
1786 /* Perform BIT_NOT_EXPR on each element individually. */
1788 {
1789 tree elem;
1791 /* This can cope with stepped encodings because ~x == -1 - x. */
1792 tree_vector_builder elements;
1796 {
1802 }
1805 }
1829 {
1852 else
1857 {
1863 }
1866 }
1875 }
1878 }
1880 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1881 indicates which particular sizetype to create. */
1883 tree
1885 {
1887 }
1888 \f
1889 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1890 is a tree code. The type of the result is taken from the operands.
1891 Both must be equivalent integer types, ala int_binop_types_match_p.
1892 If the operands are constant, so is the result. */
1894 tree
1896 {
1905 /* Handle the special case of two poly_int constants faster. */
1907 {
1908 /* And some specific cases even faster than that. */
1910 {
1917 }
1919 {
1923 }
1925 {
1929 }
1931 /* Handle general case of two integer constants. For sizetype
1932 constant calculations we always want to know about overflow,
1933 even in the unsigned case. */
1937 }
1940 }
1942 /* Given two values, either both of sizetype or both of bitsizetype,
1943 compute the difference between the two values. Return the value
1944 in signed type corresponding to the type of the operands. */
1946 tree
1948 {
1950 tree ctype;
1955 /* If the type is already signed, just do the simple thing. */
1963 else
1966 /* If either operand is not a constant, do the conversions to the signed
1967 type and subtract. The hardware will do the right thing with any
1968 overflow in the subtraction. */
1974 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1975 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1976 overflow) and negate (which can't either). Special-case a result
1977 of zero while we're here. */
1983 else
1987 MINUS_EXPR,
1989 }
1990 \f
1991 /* A subroutine of fold_convert_const handling conversions of an
1992 INTEGER_CST to another integer type. */
1994 static tree
1996 {
1997 /* Given an integer constant, make new constant with new type,
1998 appropriately sign-extended or truncated. Use widest_int
1999 so that any extension is done according ARG1's type. */
2003 }
2005 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2006 to an integer type. */
2008 static tree
2010 {
2012 tree t;
2014 /* The following code implements the floating point to integer
2015 conversion rules required by the Java Language Specification,
2016 that IEEE NaNs are mapped to zero and values that overflow
2017 the target precision saturate, i.e. values greater than
2018 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2019 are mapped to INT_MIN. These semantics are allowed by the
2020 C and C++ standards that simply state that the behavior of
2021 FP-to-integer conversion is unspecified upon overflow. */
2023 wide_int val;
2024 REAL_VALUE_TYPE r;
2028 {
2035 }
2037 /* If R is NaN, return zero and show we have an overflow. */
2039 {
2042 }
2044 /* See if R is less than the lower bound or greater than the
2045 upper bound. */
2048 {
2052 {
2055 }
2056 }
2059 {
2062 {
2065 {
2068 }
2069 }
2070 }
2077 }
2079 /* A subroutine of fold_convert_const handling conversions of a
2080 FIXED_CST to an integer type. */
2082 static tree
2084 {
2085 tree t;
2087 scalar_mode mode;
2089 /* Right shift FIXED_CST to temp by fbit. */
2093 {
2095 HOST_BITS_PER_DOUBLE_INT,
2098 /* Left shift temp to temp_trunc by fbit. */
2100 HOST_BITS_PER_DOUBLE_INT,
2102 }
2103 else
2104 {
2107 }
2109 /* If FIXED_CST is negative, we need to round the value toward 0.
2110 By checking if the fractional bits are not zero to add 1 to temp. */
2116 /* Given a fixed-point constant, make new constant with new type,
2117 appropriately sign-extended or truncated. */
2125 }
2127 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2128 to another floating point type. */
2130 static tree
2132 {
2133 REAL_VALUE_TYPE value;
2134 tree t;
2136 /* Don't perform the operation if flag_signaling_nans is on
2137 and the operand is a signaling NaN. */
2145 /* If converting an infinity or NAN to a representation that doesn't
2146 have one, set the overflow bit so that we can produce some kind of
2147 error message at the appropriate point if necessary. It's not the
2148 most user-friendly message, but it's better than nothing. */
2155 /* Regular overflow, conversion produced an infinity in a mode that
2156 can't represent them. */
2161 else
2164 }
2166 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2167 to a floating point type. */
2169 static tree
2171 {
2172 REAL_VALUE_TYPE value;
2173 tree t;
2181 }
2183 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2184 to another fixed-point type. */
2186 static tree
2188 {
2189 FIXED_VALUE_TYPE value;
2190 tree t;
2197 /* Propagate overflow flags. */
2201 }
2203 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2204 to a fixed-point type. */
2206 static tree
2208 {
2209 FIXED_VALUE_TYPE value;
2210 tree t;
2212 double_int di;
2219 else
2227 /* Propagate overflow flags. */
2231 }
2233 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2234 to a fixed-point type. */
2236 static tree
2238 {
2239 FIXED_VALUE_TYPE value;
2240 tree t;
2248 /* Propagate overflow flags. */
2252 }
2254 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2255 type TYPE. If no simplification can be done return NULL_TREE. */
2257 static tree
2259 {
2264 /* We can't widen types, since the runtime value could overflow the
2265 original type before being extended to the new type. */
2276 {
2283 }
2285 {
2292 }
2294 {
2301 }
2303 {
2306 {
2309 /* We can't handle steps directly when extending, since the
2310 values need to wrap at the original precision first. */
2311 bool step_ok_p
2315 tree_vector_builder v;
2320 {
2326 }
2328 }
2329 }
2331 }
2333 /* Construct a vector of zero elements of vector type TYPE. */
2335 static tree
2337 {
2338 tree t;
2342 }
2344 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2346 bool
2348 {
2363 {
2385 }
2386 }
2388 /* Convert expression ARG to type TYPE. Used by the middle-end for
2389 simple conversions in preference to calling the front-end's convert. */
2391 tree
2393 {
2395 tree tem;
2406 {
2409 /* Handle conversions between pointers to different address spaces. */
2414 /* fall through */
2419 {
2423 }
2437 {
2441 }
2443 {
2447 }
2449 {
2453 }
2456 {
2474 }
2479 {
2483 }
2486 {
2500 }
2504 {
2513 integer_zero_node));
2515 {
2519 {
2525 }
2533 }
2537 }
2555 }
2556 fold_convert_exit:
2559 }
2560 \f
2561 /* Return false if expr can be assumed not to be an lvalue, true
2562 otherwise. */
2564 static bool
2566 {
2567 /* We only need to wrap lvalue tree codes. */
2569 {
2601 /* Assume the worst for front-end tree codes. */
2605 }
2608 }
2610 /* Return an expr equal to X but certainly not valid as an lvalue. */
2612 tree
2614 {
2615 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2616 us. */
2623 }
2624 \f
2625 /* Given a tree comparison code, return the code that is the logical inverse.
2626 It is generally not safe to do this for floating-point comparisons, except
2627 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2628 ERROR_MARK in this case. */
2630 enum tree_code
2632 {
2638 {
2669 }
2670 }
2672 /* Similar, but return the comparison that results if the operands are
2673 swapped. This is safe for floating-point. */
2675 enum tree_code
2677 {
2679 {
2705 }
2706 }
2709 /* Convert a comparison tree code from an enum tree_code representation
2710 into a compcode bit-based encoding. This function is the inverse of
2711 compcode_to_comparison. */
2713 static enum comparison_code
2715 {
2717 {
2748 }
2749 }
2751 /* Convert a compcode bit-based encoding of a comparison operator back
2752 to GCC's enum tree_code representation. This function is the
2753 inverse of comparison_to_compcode. */
2755 static enum tree_code
2757 {
2759 {
2790 }
2791 }
2793 /* Return true if COND1 tests the opposite condition of COND2. */
2795 bool
2797 {
2800 && (invert_tree_comparison
2807 }
2809 /* Return a tree for the comparison which is the combination of
2810 doing the AND or OR (depending on CODE) of the two operations LCODE
2811 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2812 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2813 if this makes the transformation invalid. */
2815 tree
2820 {
2827 {
2838 }
2841 {
2842 /* Eliminate unordered comparisons, as well as LTGT and ORD
2843 which are not used unless the mode has NaNs. */
2849 }
2851 {
2852 /* Check that the original operation and the optimized ones will trap
2853 under the same condition. */
2864 /* In a short-circuited boolean expression the LHS might be
2865 such that the RHS, if evaluated, will never trap. For
2866 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2867 if neither x nor y is NaN. (This is a mixed blessing: for
2868 example, the expression above will never trap, hence
2869 optimizing it to x < y would be invalid). */
2874 /* If the comparison was short-circuited, and only the RHS
2875 trapped, we may now generate a spurious trap. */
2880 /* If we changed the conditions that cause a trap, we lose. */
2883 }
2889 else
2890 {
2895 }
2896 }
2897 \f
2898 /* Return nonzero if two operands (typically of the same tree node)
2899 are necessarily equal. FLAGS modifies behavior as follows:
2901 If OEP_ONLY_CONST is set, only return nonzero for constants.
2902 This function tests whether the operands are indistinguishable;
2903 it does not test whether they are equal using C's == operation.
2904 The distinction is important for IEEE floating point, because
2905 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2906 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2908 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2909 even though it may hold multiple values during a function.
2910 This is because a GCC tree node guarantees that nothing else is
2911 executed between the evaluation of its "operands" (which may often
2912 be evaluated in arbitrary order). Hence if the operands themselves
2913 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2914 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2915 unset means assuming isochronic (or instantaneous) tree equivalence.
2916 Unless comparing arbitrary expression trees, such as from different
2917 statements, this flag can usually be left unset.
2919 If OEP_PURE_SAME is set, then pure functions with identical arguments
2920 are considered the same. It is used when the caller has other ways
2921 to ensure that global memory is unchanged in between.
2923 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2924 not values of expressions.
2926 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2927 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2929 If OEP_BITWISE is set, then require the values to be bitwise identical
2930 rather than simply numerically equal. Do not take advantage of things
2931 like math-related flags or undefined behavior; only return true for
2932 values that are provably bitwise identical in all circumstances.
2934 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2935 any operand with side effect. This is unnecesarily conservative in the
2936 case we know that arg0 and arg1 are in disjoint code paths (such as in
2937 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2938 addresses with TREE_CONSTANT flag set so we know that &var == &var
2939 even if var is volatile. */
2941 bool
2944 {
2952 /* If either is ERROR_MARK, they aren't equal. */
2958 /* Similar, if either does not have a type (like a template id),
2959 they aren't equal. */
2963 /* Bitwise identity makes no sense if the values have different layouts. */
2968 /* We cannot consider pointers to different address space equal. */
2975 /* Check equality of integer constants before bailing out due to
2976 precision differences. */
2978 {
2979 /* Address of INTEGER_CST is not defined; check that we did not forget
2980 to drop the OEP_ADDRESS_OF flags. */
2983 }
2986 {
2987 /* If both types don't have the same signedness, then we can't consider
2988 them equal. We must check this before the STRIP_NOPS calls
2989 because they may change the signedness of the arguments. As pointers
2990 strictly don't have a signedness, require either two pointers or
2991 two non-pointers as well. */
2997 /* If both types don't have the same precision, then it is not safe
2998 to strip NOPs. */
3005 }
3006 #if 0
3007 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3008 sanity check once the issue is solved. */
3009 else
3010 /* Addresses of conversions and SSA_NAMEs (and many other things)
3011 are not defined. Check that we did not forget to drop the
3012 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3015 #endif
3017 /* In case both args are comparisons but with different comparison
3018 code, try to swap the comparison operands of one arg to produce
3019 a match and compare that variant. */
3023 {
3031 }
3034 {
3035 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3037 ;
3039 {
3040 /* If we are interested in comparing addresses ignore
3041 MEM_REF wrappings of the base that can appear just for
3042 TBAA reasons. */
3056 }
3057 else
3059 }
3061 /* When not checking adddresses, this is needed for conversions and for
3062 COMPONENT_REF. Might as well play it safe and always test this. */
3069 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3070 We don't care about side effects in that case because the SAVE_EXPR
3071 takes care of that for us. In all other cases, two expressions are
3072 equal if they have no side effects. If we have two identical
3073 expressions with side effects that should be treated the same due
3074 to the only side effects being identical SAVE_EXPR's, that will
3075 be detected in the recursive calls below.
3076 If we are taking an invariant address of two identical objects
3077 they are necessarily equal as well. */
3084 /* Next handle constant cases, those for which we can return 1 even
3085 if ONLY_CONST is set. */
3088 {
3101 {
3102 /* If we do not distinguish between signed and unsigned zero,
3103 consider them equal. */
3106 }
3110 {
3125 }
3129 flags)
3131 flags));
3142 flags | OEP_ADDRESS_OF
3145 /* In GIMPLE empty constructors are allowed in initializers of
3146 aggregates. */
3150 }
3152 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3153 two instances of undefined behavior will give identical results. */
3157 /* Define macros to test an operand from arg0 and arg1 for equality and a
3158 variant that allows null and views null as being different from any
3159 non-null value. In the latter case, if either is null, the both
3160 must be; otherwise, do the normal comparison. */
3161 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3162 TREE_OPERAND (arg1, N), flags)
3164 #define OP_SAME_WITH_NULL(N) \
3165 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3166 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3169 {
3171 /* Two conversions are equal only if signedness and modes match. */
3173 {
3174 CASE_CONVERT:
3182 }
3192 /* For commutative ops, allow the other order. */
3200 /* If either of the pointer (or reference) expressions we are
3201 dereferencing contain a side effect, these cannot be equal,
3202 but their addresses can be. */
3209 {
3212 {
3216 /* Verify that the access types are compatible. */
3220 }
3225 /* Require the same offset. */
3231 /* Fallthru. */
3239 {
3240 /* Require equal access sizes */
3246 flags)))
3248 /* Verify that access happens in similar types. */
3251 /* Verify that accesses are TBAA compatible. */
3260 /* Verify that alignment is compatible. */
3264 }
3267 /* TARGET_MEM_REF require equal extra operands. */
3278 /* Compare the array index by value if it is constant first as we
3279 may have different types but same value here. */
3285 /* Compare low bound and element size as with OEP_ADDRESS_OF
3286 we have to account for the offset of the ref. */
3291 array_ref_low_bound
3295 array_ref_element_size
3297 flags))));
3300 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3301 may be NULL when we're called to compare MEM_EXPRs. */
3304 {
3307 /* Most of time we only need to compare FIELD_DECLs for equality.
3308 However when determining address look into actual offsets.
3309 These may match for unions and unshared record types. */
3312 {
3315 {
3326 flags))
3328 }
3329 else
3331 }
3332 }
3343 }
3347 {
3349 /* Be sure we pass right ADDRESS_OF flag. */
3366 /* The multiplcation operands are commutative. */
3367 /* FALLTHRU */
3375 /* Otherwise take into account this is a commutative operation. */
3388 /* BIT_INSERT_EXPR has an implict operand as the type precision
3389 of op1. Need to check to make sure they are the same. */
3395 /* FALLTHRU */
3420 /* Virtual table reference. */
3432 {
3437 }
3442 }
3446 {
3450 /* If not both CALL_EXPRs are either internal or normal function
3451 functions, then they are not equal. */
3454 {
3455 /* If the CALL_EXPRs call different internal functions, then they
3456 are not equal. */
3459 }
3460 else
3461 {
3462 /* If the CALL_EXPRs call different functions, then they are not
3463 equal. */
3465 flags))
3467 }
3469 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3470 {
3474 else
3478 }
3480 /* Now see if all the arguments are the same. */
3481 {
3492 /* If we get here and both argument lists are exhausted
3493 then the CALL_EXPRs are equal. */
3495 }
3498 }
3501 /* Consider __builtin_sqrt equal to sqrt. */
3511 {
3512 /* Consider decls with the same name equal. The caller needs
3513 to make sure they refer to the same entity (such as a function
3514 formal parameter). */
3520 }
3525 {
3529 /* In GIMPLE constructors are used only to build vectors from
3530 elements. Individual elements in the constructor must be
3531 indexed in increasing order and form an initial sequence.
3533 We make no effort to compare constructors in generic.
3534 (see sem_variable::equals in ipa-icf which can do so for
3535 constants). */
3540 /* Be sure that vectors constructed have the same representation.
3541 We only tested element precision and modes to match.
3542 Vectors may be BLKmode and thus also check that the number of
3543 parts match. */
3556 {
3561 /* In GIMPLE the indexes can be either NULL or matching i.
3562 Double check this so we won't get false
3563 positives for GENERIC. */
3571 }
3573 }
3576 {
3577 /* Compare the STATEMENT_LISTs. */
3583 {
3584 /* The lists don't have the same number of statements. */
3590 flags & (OEP_LEXICOGRAPHIC
3593 }
3594 }
3599 {
3610 }
3614 }
3616 #undef OP_SAME
3617 #undef OP_SAME_WITH_NULL
3618 }
3620 /* Generate a hash value for an expression. This can be used iteratively
3621 by passing a previous result as the HSTATE argument. */
3623 void
3626 {
3632 {
3635 }
3645 {
3646 /* Alas, constants aren't shared, so we can't rely on pointer
3647 identity. */
3657 {
3661 else
3665 }
3667 {
3671 }
3681 {
3688 }
3690 /* We can just compare by pointer. */
3694 /* The node itself doesn't matter. */
3698 /* Ignore. */
3701 /* A list of expressions, for a CALL_EXPR or as the elements of a
3702 VECTOR_CST. */
3707 {
3713 {
3714 /* In GIMPLE the indexes can be either NULL or matching i. */
3719 }
3721 }
3723 {
3724 tree_stmt_iterator i;
3729 }
3738 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3739 Otherwise nodes that compare equal according to operand_equal_p might
3740 get different hash codes. However, don't do this for machine specific
3741 or front end builtins, since the function code is overloaded in those
3742 cases. */
3745 {
3748 }
3749 /* FALL THROUGH */
3752 {
3756 }
3760 {
3761 /* DECL's have a unique ID */
3763 }
3765 {
3766 /* For comparisons that can be swapped, use the lower
3767 tree code. */
3774 }
3776 {
3777 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3778 operand_equal_p. */
3782 /* Don't hash the type, that can lead to having nodes which
3783 compare equal according to operand_equal_p, but which
3784 have different hash codes. Make sure to include signedness
3785 in the hash computation. */
3788 }
3789 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3797 /* Don't ICE on FE specific trees, or their arguments etc.
3798 during operand_equal_p hash verification. */
3801 else
3802 {
3808 {
3824 {
3829 else
3830 {
3836 }
3838 }
3852 {
3853 /* The multiplication operands are commutative. */
3860 }
3868 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3869 Usually different TARGET_EXPRs just should use
3870 different temporaries in their slots. */
3875 /* Virtual table reference. */
3883 {
3885 /* We compute mangled names only when free_lang_data is run.
3886 In that case we can hash precisely. */
3889 hstate.add_object
3890 (IDENTIFIER_HASH_VALUE
3892 }
3896 }
3898 /* Don't hash the type, that can lead to having nodes which
3899 compare equal according to operand_equal_p, but which
3900 have different hash codes. */
3902 {
3903 /* Make sure to include signness in the hash computation. */
3906 }
3909 {
3910 /* It's a commutative expression. We want to hash it the same
3911 however it appears. We do this by first hashing both operands
3912 and then rehashing based on the order of their independent
3913 hashes. */
3918 }
3919 else
3923 }
3925 }
3926 }
3928 bool
3931 {
3932 /* When checking and unless comparing DECL names, verify that if
3933 the outermost operand_equal_p call returns non-zero then ARG0
3934 and ARG1 have the same hash value. */
3936 {
3938 {
3940 {
3947 }
3949 }
3950 else
3954 }
3957 }
3962 /* Conveinece wrapper around operand_compare class because usually we do
3963 not need to play with the valueizer. */
3965 bool
3967 {
3969 }
3971 namespace inchash
3972 {
3974 /* Generate a hash value for an expression. This can be used iteratively
3975 by passing a previous result as the HSTATE argument.
3977 This function is intended to produce the same hash for expressions which
3978 would compare equal using operand_equal_p. */
3979 void
3981 {
3983 }
3985 }
3986 \f
3987 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3988 with a different signedness or a narrower precision. */
3990 static bool
3992 {
4000 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4001 and see if the inner values are the same. This removes any
4002 signedness comparison, which doesn't matter here. */
4010 /* Discard a single widening conversion from ARG1 and see if the inner
4011 value is the same as ARG0. */
4020 }
4021 \f
4022 /* See if ARG is an expression that is either a comparison or is performing
4023 arithmetic on comparisons. The comparisons must only be comparing
4024 two different values, which will be stored in *CVAL1 and *CVAL2; if
4025 they are nonzero it means that some operands have already been found.
4026 No variables may be used anywhere else in the expression except in the
4027 comparisons.
4029 If this is true, return 1. Otherwise, return zero. */
4031 static bool
4033 {
4037 /* We can handle some of the tcc_expression cases here. */
4046 {
4065 /* First see if we can handle the first operand, then the second. For
4066 the second operand, we know *CVAL1 can't be zero. It must be that
4067 one side of the comparison is each of the values; test for the
4068 case where this isn't true by failing if the two operands
4069 are the same. */
4078 ;
4082 ;
4083 else
4087 ;
4091 ;
4092 else
4099 }
4100 }
4101 \f
4102 /* ARG is a tree that is known to contain just arithmetic operations and
4103 comparisons. Evaluate the operations in the tree substituting NEW0 for
4104 any occurrence of OLD0 as an operand of a comparison and likewise for
4105 NEW1 and OLD1. */
4107 static tree
4110 {
4115 /* We can handle some of the tcc_expression cases here. */
4123 {
4138 {
4157 }
4158 /* Fall through - ??? */
4161 {
4165 /* We need to check both for exact equality and tree equality. The
4166 former will be true if the operand has a side-effect. In that
4167 case, we know the operand occurred exactly once. */
4180 }
4184 }
4185 }
4186 \f
4187 /* Return a tree for the case when the result of an expression is RESULT
4188 converted to TYPE and OMITTED was previously an operand of the expression
4189 but is now not needed (e.g., we folded OMITTED * 0).
4191 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4192 the conversion of RESULT to TYPE. */
4194 tree
4196 {
4199 /* If the resulting operand is an empty statement, just return the omitted
4200 statement casted to void. */
4210 }
4212 /* Return a tree for the case when the result of an expression is RESULT
4213 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4214 of the expression but are now not needed.
4216 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4217 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4218 evaluated before OMITTED2. Otherwise, if neither has side effects,
4219 just do the conversion of RESULT to TYPE. */
4221 tree
4224 {
4233 }
4235 \f
4236 /* Return a simplified tree node for the truth-negation of ARG. This
4237 never alters ARG itself. We assume that ARG is an operation that
4238 returns a truth value (0 or 1).
4240 FIXME: one would think we would fold the result, but it causes
4241 problems with the dominator optimizer. */
4243 static tree
4245 {
4250 /* If this is a comparison, we can simply invert it, except for
4251 floating-point non-equality comparisons, in which case we just
4252 enclose a TRUTH_NOT_EXPR around what we have. */
4255 {
4258 && flag_trapping_math
4271 }
4274 {
4293 /* Here we can invert either operand. We invert the first operand
4294 unless the second operand is a TRUTH_NOT_EXPR in which case our
4295 result is the XOR of the first operand with the inside of the
4296 negation of the second operand. */
4301 else
4324 {
4331 /* A COND_EXPR may have a throw as one operand, which
4332 then has void type. Just leave void operands
4333 as they are. */
4339 }
4351 CASE_CONVERT:
4355 /* fall through */
4377 }
4378 }
4380 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4381 assume that ARG is an operation that returns a truth value (0 or 1
4382 for scalars, 0 or -1 for vectors). Return the folded expression if
4383 folding is successful. Otherwise, return NULL_TREE. */
4385 static tree
4387 {
4390 ? BIT_NOT_EXPR
4393 }
4395 /* Return a simplified tree node for the truth-negation of ARG. This
4396 never alters ARG itself. We assume that ARG is an operation that
4397 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4399 tree
4401 {
4407 ? BIT_NOT_EXPR
4410 }
4411 \f
4412 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4413 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4414 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4415 is the original memory reference used to preserve the alias set of
4416 the access. */
4418 static tree
4422 {
4425 /* Attempt not to lose the access path if possible. */
4427 {
4429 machine_mode nmode;
4431 tree noffset;
4439 && !reversep
4440 && !nreversep
4442 {
4445 }
4446 }
4455 {
4462 }
4477 }
4479 /* Optimize a bit-field compare.
4481 There are two cases: First is a compare against a constant and the
4482 second is a comparison of two items where the fields are at the same
4483 bit position relative to the start of a chunk (byte, halfword, word)
4484 large enough to contain it. In these cases we can avoid the shift
4485 implicit in bitfield extractions.
4487 For constants, we emit a compare of the shifted constant with the
4488 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4489 compared. For two fields at the same position, we do the ANDs with the
4490 similar mask and compare the result of the ANDs.
4492 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4493 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4494 are the left and right operands of the comparison, respectively.
4496 If the optimization described above can be done, we return the resulting
4497 tree. Otherwise we return zero. */
4499 static tree
4502 {
4506 tree unsigned_type;
4509 scalar_int_mode nmode;
4514 tree mask;
4515 tree offset;
4517 /* Get all the information about the extractions being done. If the bit size
4518 is the same as the size of the underlying object, we aren't doing an
4519 extraction at all and so can do nothing. We also don't want to
4520 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4521 then will no longer be able to replace it. */
4536 else
4537 {
4538 /* If this is not a constant, we can only do something if bit positions,
4539 sizes, signedness and storage order are the same. */
4540 rinner
4553 }
4555 /* Honor the C++ memory model and mimic what RTL expansion does. */
4559 {
4563 }
4565 /* See if we can find a mode to refer to this field. We should be able to,
4566 but fail if we can't. */
4574 /* Set signed and unsigned types of the precision of this mode for the
4575 shifts below. */
4578 /* Compute the bit position and size for the new reference and our offset
4579 within it. If the new reference is the same size as the original, we
4580 won't optimize anything, so return zero. */
4590 /* Make the mask to be used against the extracted field. */
4597 {
4601 /* If not comparing with constant, just rework the comparison
4602 and return. */
4610 }
4612 /* Otherwise, we are handling the constant case. See if the constant is too
4613 big for the field. Warn and return a tree for 0 (false) if so. We do
4614 this not only for its own sake, but to avoid having to test for this
4615 error case below. If we didn't, we might generate wrong code.
4617 For unsigned fields, the constant shifted right by the field length should
4618 be all zero. For signed fields, the high-order bits should agree with
4619 the sign bit. */
4622 {
4624 {
4628 }
4629 }
4630 else
4631 {
4634 {
4638 }
4639 }
4644 /* Single-bit compares should always be against zero. */
4646 {
4649 }
4651 /* Make a new bitfield reference, shift the constant over the
4652 appropriate number of bits and mask it with the computed mask
4653 (in case this was a signed field). If we changed it, make a new one. */
4661 mask);
4666 }
4667 \f
4668 /* Subroutine for fold_truth_andor_1: decode a field reference.
4670 If EXP is a comparison reference, we return the innermost reference.
4672 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4673 set to the starting bit number.
4675 If the innermost field can be completely contained in a mode-sized
4676 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4678 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4679 otherwise it is not changed.
4681 *PUNSIGNEDP is set to the signedness of the field.
4683 *PREVERSEP is set to the storage order of the field.
4685 *PMASK is set to the mask used. This is either contained in a
4686 BIT_AND_EXPR or derived from the width of the field.
4688 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4690 Return 0 if this is not a component reference or is one that we can't
4691 do anything with. */
4693 static tree
4698 {
4703 tree unsigned_type;
4706 /* All the optimizations using this function assume integer fields.
4707 There are problems with FP fields since the type_for_size call
4708 below can fail for, e.g., XFmode. */
4712 /* We are interested in the bare arrangement of bits, so strip everything
4713 that doesn't affect the machine mode. However, record the type of the
4714 outermost expression if it may matter below. */
4721 {
4727 }
4738 /* Reject out-of-bound accesses (PR79731). */
4750 /* If the number of bits in the reference is the same as the bitsize of
4751 the outer type, then the outer type gives the signedness. Otherwise
4752 (in case of a small bitfield) the signedness is unchanged. */
4756 /* Compute the mask to access the bitfield. */
4764 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4772 }
4774 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4775 bit positions and MASK is SIGNED. */
4777 static bool
4779 {
4783 /* If this function returns true when the type of the mask is
4784 UNSIGNED, then there will be errors. In particular see
4785 gcc.c-torture/execute/990326-1.c. There does not appear to be
4786 any documentation paper trail as to why this is so. But the pre
4787 wide-int worked with that restriction and it has been preserved
4788 here. */
4793 }
4795 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4796 represents the sign bit of EXP's type. If EXP represents a sign
4797 or zero extension, also test VAL against the unextended type.
4798 The return value is the (sub)expression whose sign bit is VAL,
4799 or NULL_TREE otherwise. */
4801 tree
4803 {
4805 tree t;
4807 /* Tree EXP must have an integral type. */
4812 /* Tree VAL must be an integer constant. */
4821 /* Handle extension from a narrower type. */
4827 }
4829 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4830 to be evaluated unconditionally. */
4832 static bool
4834 {
4835 /* Strip any conversions that don't change the machine mode. */
4844 /* Don't regard global variables as simple. They may be
4845 allocated in ways unknown to the compiler (shared memory,
4846 #pragma weak, etc). */
4849 /* Weakrefs are not safe to be read, since they can be NULL.
4850 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4851 have DECL_WEAK flag set. */
4853 /* Loading a static variable is unduly expensive, but global
4854 registers aren't expensive. */
4856 }
4858 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4859 to be evaluated unconditionally.
4860 I addition to simple_operand_p, we assume that comparisons, conversions,
4861 and logic-not operations are simple, if their operands are simple, too. */
4863 static bool
4865 {
4884 }
4886 \f
4887 /* The following functions are subroutines to fold_range_test and allow it to
4888 try to change a logical combination of comparisons into a range test.
4890 For example, both
4891 X == 2 || X == 3 || X == 4 || X == 5
4892 and
4893 X >= 2 && X <= 5
4894 are converted to
4895 (unsigned) (X - 2) <= 3
4897 We describe each set of comparisons as being either inside or outside
4898 a range, using a variable named like IN_P, and then describe the
4899 range with a lower and upper bound. If one of the bounds is omitted,
4900 it represents either the highest or lowest value of the type.
4902 In the comments below, we represent a range by two numbers in brackets
4903 preceded by a "+" to designate being inside that range, or a "-" to
4904 designate being outside that range, so the condition can be inverted by
4905 flipping the prefix. An omitted bound is represented by a "-". For
4906 example, "- [-, 10]" means being outside the range starting at the lowest
4907 possible value and ending at 10, in other words, being greater than 10.
4908 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4909 always false.
4911 We set up things so that the missing bounds are handled in a consistent
4912 manner so neither a missing bound nor "true" and "false" need to be
4913 handled using a special case. */
4915 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4916 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4917 and UPPER1_P are nonzero if the respective argument is an upper bound
4918 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4919 must be specified for a comparison. ARG1 will be converted to ARG0's
4920 type if both are specified. */
4922 static tree
4925 {
4926 tree tem;
4930 /* If neither arg represents infinity, do the normal operation.
4931 Else, if not a comparison, return infinity. Else handle the special
4932 comparison rules. Note that most of the cases below won't occur, but
4933 are handled for consistency. */
4936 {
4941 }
4946 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4947 for neither. In real maths, we cannot assume open ended ranges are
4948 the same. But, this is computer arithmetic, where numbers are finite.
4949 We can therefore make the transformation of any unbounded range with
4950 the value Z, Z being greater than any representable number. This permits
4951 us to treat unbounded ranges as equal. */
4955 {
4976 }
4979 }
4980 \f
4981 /* Helper routine for make_range. Perform one step for it, return
4982 new expression if the loop should continue or NULL_TREE if it should
4983 stop. */
4985 tree
4989 {
4995 {
4997 /* We can only do something if the range is testing for zero. */
5006 /* We can only do something if the range is testing for zero
5007 and if the second operand is an integer constant. Note that
5008 saying something is "in" the range we make is done by
5009 complementing IN_P since it will set in the initial case of
5010 being not equal to zero; "out" is leaving it alone. */
5017 {
5038 }
5040 /* If this is an unsigned comparison, we also know that EXP is
5041 greater than or equal to zero. We base the range tests we make
5042 on that fact, so we record it here so we can parse existing
5043 range tests. We test arg0_type since often the return type
5044 of, e.g. EQ_EXPR, is boolean. */
5046 {
5050 NULL_TREE))
5055 /* If the high bound is missing, but we have a nonzero low
5056 bound, reverse the range so it goes from zero to the low bound
5057 minus 1. */
5059 {
5064 }
5065 }
5073 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5074 low and high are non-NULL, then normalize will DTRT. */
5077 {
5082 }
5084 /* (-x) IN [a,b] -> x in [-b, -a] */
5096 /* ~ X -> -X - 1 */
5105 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5106 move a constant to the other side. */
5111 /* If EXP is signed, any overflow in the computation is undefined,
5112 so we don't worry about it so long as our computations on
5113 the bounds don't overflow. For unsigned, overflow is defined
5114 and this is exactly the right thing. */
5126 normalize:
5127 /* Check for an unsigned range which has wrapped around the maximum
5128 value thus making n_high < n_low, and normalize it. */
5130 {
5136 /* If the range is of the form +/- [ x+1, x ], we won't
5137 be able to normalize it. But then, it represents the
5138 whole range or the empty set, so make it
5139 +/- [ -, - ]. */
5143 else
5145 }
5146 else
5154 CASE_CONVERT:
5172 /* If we're converting arg0 from an unsigned type, to exp,
5173 a signed type, we will be doing the comparison as unsigned.
5174 The tests above have already verified that LOW and HIGH
5175 are both positive.
5177 So we have to ensure that we will handle large unsigned
5178 values the same way that the current signed bounds treat
5179 negative values. */
5182 {
5183 tree high_positive;
5184 tree equiv_type;
5185 /* For fixed-point modes, we need to pass the saturating flag
5186 as the 2nd parameter. */
5188 equiv_type
5191 else
5192 equiv_type
5195 /* A range without an upper bound is, naturally, unbounded.
5196 Since convert would have cropped a very large value, use
5197 the max value for the destination type. */
5198 high_positive
5205 high_positive),
5208 /* If the low bound is specified, "and" the range with the
5209 range for which the original unsigned value will be
5210 positive. */
5212 {
5215 integer_zero_node),
5216 high_positive))
5220 }
5221 else
5222 {
5223 /* Otherwise, "or" the range with the range of the input
5224 that will be interpreted as negative. */
5227 integer_zero_node),
5228 high_positive))
5232 }
5233 }
5242 }
5243 }
5245 /* Given EXP, a logical expression, set the range it is testing into
5246 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5247 actually being tested. *PLOW and *PHIGH will be made of the same
5248 type as the returned expression. If EXP is not a comparison, we
5249 will most likely not be returning a useful value and range. Set
5250 *STRICT_OVERFLOW_P to true if the return value is only valid
5251 because signed overflow is undefined; otherwise, do not change
5252 *STRICT_OVERFLOW_P. */
5254 tree
5257 {
5265 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5266 and see if we can refine the range. Some of the cases below may not
5267 happen, but it doesn't seem worth worrying about this. We "continue"
5268 the outer loop when we've changed something; otherwise we "break"
5269 the switch, which will "break" the while. */
5275 {
5281 {
5289 }
5298 }
5300 /* If EXP is a constant, we can evaluate whether this is true or false. */
5302 {
5309 }
5313 }
5315 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5316 a bitwise check i.e. when
5317 LOW == 0xXX...X00...0
5318 HIGH == 0xXX...X11...1
5319 Return corresponding mask in MASK and stem in VALUE. */
5321 static bool
5324 {
5347 }
5348 \f
5349 /* Helper routine for build_range_check and match.pd. Return the type to
5350 perform the check or NULL if it shouldn't be optimized. */
5352 tree
5354 {
5355 /* First make sure that arithmetics in this type is valid, then make sure
5356 that it wraps around. */
5361 {
5364 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5365 for the type in question, as we rely on this here. */
5375 else
5377 }
5381 }
5383 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5384 type, TYPE, return an expression to test if EXP is in (or out of, depending
5385 on IN_P) the range. Return 0 if the test couldn't be created. */
5387 tree
5390 {
5393 /* Disable this optimization for function pointer expressions
5394 on targets that require function pointer canonicalization. */
5401 {
5407 }
5429 value);
5432 {
5434 {
5438 }
5440 }
5442 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5444 {
5448 {
5450 {
5453 etype
5455 else
5458 }
5461 }
5462 }
5464 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5465 This requires wrap-around arithmetics for the type of the expression. */
5482 }
5483 \f
5484 /* Return the predecessor of VAL in its type, handling the infinite case. */
5486 static tree
5488 {
5494 else
5497 }
5499 /* Return the successor of VAL in its type, handling the infinite case. */
5501 static tree
5503 {
5509 else
5512 }
5514 /* Given two ranges, see if we can merge them into one. Return 1 if we
5515 can, 0 if we can't. Set the output range into the specified parameters. */
5517 bool
5520 {
5524 tree tem;
5534 /* Make range 0 be the range that starts first, or ends last if they
5535 start at the same value. Swap them if it isn't. */
5538 || (lowequal
5541 {
5545 }
5547 /* If the second range is != high1 where high1 is the type maximum of
5548 the type, try first merging with < high1 range. */
5550 && high1
5557 {
5562 /* Similarly for the second range != low1 where low1 is the type minimum
5563 of the type, try first merging with > low1 range. */
5568 }
5570 /* Now flag two cases, whether the ranges are disjoint or whether the
5571 second range is totally subsumed in the first. Note that the tests
5572 below are simplified by the ones above. */
5578 /* We now have four cases, depending on whether we are including or
5579 excluding the two ranges. */
5581 {
5582 /* If they don't overlap, the result is false. If the second range
5583 is a subset it is the result. Otherwise, the range is from the start
5584 of the second to the end of the first. */
5589 else
5591 }
5594 {
5595 /* If they don't overlap, the result is the first range. If they are
5596 equal, the result is false. If the second range is a subset of the
5597 first, and the ranges begin at the same place, we go from just after
5598 the end of the second range to the end of the first. If the second
5599 range is not a subset of the first, or if it is a subset and both
5600 ranges end at the same place, the range starts at the start of the
5601 first range and ends just before the second range.
5602 Otherwise, we can't describe this as a single range. */
5608 {
5613 {
5614 /* We are in the weird situation where high0 > high1 but
5615 high1 has no successor. Punt. */
5617 }
5618 }
5620 {
5625 {
5626 /* low0 < low1 but low1 has no predecessor. Punt. */
5628 }
5629 }
5630 else
5632 }
5635 {
5636 /* If they don't overlap, the result is the second range. If the second
5637 is a subset of the first, the result is false. Otherwise,
5638 the range starts just after the first range and ends at the
5639 end of the second. */
5644 else
5645 {
5650 {
5651 /* high1 > high0 but high0 has no successor. Punt. */
5653 }
5654 }
5655 }
5657 else
5658 {
5659 /* The case where we are excluding both ranges. Here the complex case
5660 is if they don't overlap. In that case, the only time we have a
5661 range is if they are adjacent. If the second is a subset of the
5662 first, the result is the first. Otherwise, the range to exclude
5663 starts at the beginning of the first range and ends at the end of the
5664 second. */
5666 {
5671 else
5672 {
5673 /* Canonicalize - [min, x] into - [-, x]. */
5676 {
5679 GET_MODE_BITSIZE
5682 /* FALLTHROUGH */
5695 }
5697 /* Canonicalize - [x, max] into - [x, -]. */
5700 {
5703 GET_MODE_BITSIZE
5706 /* FALLTHROUGH */
5722 }
5724 /* The ranges might be also adjacent between the maximum and
5725 minimum values of the given type. For
5726 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5727 return + [x + 1, y - 1]. */
5729 {
5736 }
5737 else
5739 }
5740 }
5743 else
5745 }
5749 }
5750 \f
5752 /* Subroutine of fold, looking inside expressions of the form
5753 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5754 are the three operands of the COND_EXPR. This function is
5755 being used also to optimize A op B ? C : A, by reversing the
5756 comparison first.
5758 Return a folded expression whose code is not a COND_EXPR
5759 anymore, or NULL_TREE if no folding opportunity is found. */
5761 static tree
5765 {
5767 tree tem;
5772 /* If we have A op 0 ? A : -A, consider applying the following
5773 transformations:
5775 A == 0? A : -A same as -A
5776 A != 0? A : -A same as A
5777 A >= 0? A : -A same as abs (A)
5778 A > 0? A : -A same as abs (A)
5779 A <= 0? A : -A same as -abs (A)
5780 A < 0? A : -A same as -abs (A)
5782 None of these transformations work for modes with signed
5783 zeros. If A is +/-0, the first two transformations will
5784 change the sign of the result (from +0 to -0, or vice
5785 versa). The last four will fix the sign of the result,
5786 even though the original expressions could be positive or
5787 negative, depending on the sign of A.
5789 Note that all these transformations are correct if A is
5790 NaN, since the two alternatives (A and -A) are also NaNs. */
5797 /* In the case that A is of the form X-Y, '-A' (arg2) may
5798 have already been folded to Y-X, check for that. */
5806 {
5818 /* Fall through. */
5829 /* FALLTHRU */
5836 {
5837 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5838 is not, invokes UB both in abs and in the negation of it.
5839 So, use ABSU_EXPR instead. */
5844 }
5845 else
5846 {
5849 }
5853 }
5855 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5856 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5857 both transformations are correct when A is NaN: A != 0
5858 is then true, and A == 0 is false. */
5862 {
5867 }
5869 /* Try some transformations of A op B ? A : B.
5871 A == B? A : B same as B
5872 A != B? A : B same as A
5873 A >= B? A : B same as max (A, B)
5874 A > B? A : B same as max (B, A)
5875 A <= B? A : B same as min (A, B)
5876 A < B? A : B same as min (B, A)
5878 As above, these transformations don't work in the presence
5879 of signed zeros. For example, if A and B are zeros of
5880 opposite sign, the first two transformations will change
5881 the sign of the result. In the last four, the original
5882 expressions give different results for (A=+0, B=-0) and
5883 (A=-0, B=+0), but the transformed expressions do not.
5885 The first two transformations are correct if either A or B
5886 is a NaN. In the first transformation, the condition will
5887 be false, and B will indeed be chosen. In the case of the
5888 second transformation, the condition A != B will be true,
5889 and A will be chosen.
5891 The conversions to max() and min() are not correct if B is
5892 a number and A is not. The conditions in the original
5893 expressions will be false, so all four give B. The min()
5894 and max() versions would give a NaN instead. */
5897 /* Avoid these transformations if the COND_EXPR may be used
5898 as an lvalue in the C++ front-end. PR c++/19199. */
5899 && (in_gimple_form
5905 {
5911 {
5920 /* In C++ a ?: expression can be an lvalue, so put the
5921 operand which will be used if they are equal first
5922 so that we can convert this back to the
5923 corresponding COND_EXPR. */
5925 {
5933 }
5940 {
5948 }
5961 }
5962 }
5965 }
5968 \f
5969 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5970 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5971 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5972 false) >= 2)
5973 #endif
5975 /* EXP is some logical combination of boolean tests. See if we can
5976 merge it into some range test. Return the new tree if so. */
5978 static tree
5981 {
5995 /* If op0 is known true or false and this is a short-circuiting
5996 operation we must not merge with op1 since that makes side-effects
5997 unconditional. So special-case this. */
6004 /* If this is an OR operation, invert both sides; we will invert
6005 again at the end. */
6009 /* If both expressions are the same, if we can merge the ranges, and we
6010 can build the range test, return it or it inverted. If one of the
6011 ranges is always true or always false, consider it to be the same
6012 expression as the other. */
6020 {
6024 }
6026 /* On machines where the branch cost is expensive, if this is a
6027 short-circuited branch and the underlying object on both sides
6028 is the same, make a non-short-circuit operation. */
6031 logical_op_non_short_circuit
6038 {
6039 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6040 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6041 which cases we can't do this. */
6049 {
6058 {
6061 WARN_STRICT_OVERFLOW_COMPARISON);
6065 }
6066 }
6067 }
6070 }
6071 \f
6072 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6073 bit value. Arrange things so the extra bits will be set to zero if and
6074 only if C is signed-extended to its full width. If MASK is nonzero,
6075 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6077 static tree
6079 {
6082 tree temp;
6087 /* We work by getting just the sign bit into the low-order bit, then
6088 into the high-order bit, then sign-extend. We then XOR that value
6089 with C. */
6093 /* We must use a signed type in order to get an arithmetic right shift.
6094 However, we must also avoid introducing accidental overflows, so that
6095 a subsequent call to integer_zerop will work. Hence we must
6096 do the type conversion here. At this point, the constant is either
6097 zero or one, and the conversion to a signed type can never overflow.
6098 We could get an overflow if this conversion is done anywhere else. */
6107 /* If necessary, convert the type back to match the type of C. */
6112 }
6113 \f
6114 /* For an expression that has the form
6115 (A && B) || ~B
6116 or
6117 (A || B) && ~B,
6118 we can drop one of the inner expressions and simplify to
6119 A || ~B
6120 or
6121 A && ~B
6122 LOC is the location of the resulting expression. OP is the inner
6123 logical operation; the left-hand side in the examples above, while CMPOP
6124 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6125 removing a condition that guards another, as in
6126 (A != NULL && A->...) || A == NULL
6127 which we must not transform. If RHS_ONLY is true, only eliminate the
6128 right-most operand of the inner logical operation. */
6130 static tree
6133 {
6151 {
6154 {
6157 }
6158 }
6160 {
6163 {
6166 }
6167 }
6182 }
6184 /* Find ways of folding logical expressions of LHS and RHS:
6185 Try to merge two comparisons to the same innermost item.
6186 Look for range tests like "ch >= '0' && ch <= '9'".
6187 Look for combinations of simple terms on machines with expensive branches
6188 and evaluate the RHS unconditionally.
6190 For example, if we have p->a == 2 && p->b == 4 and we can make an
6191 object large enough to span both A and B, we can do this with a comparison
6192 against the object ANDed with the a mask.
6194 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6195 operations to do this with one comparison.
6197 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6198 function and the one above.
6200 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6201 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6203 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6204 two operands.
6206 We return the simplified tree or 0 if no optimization is possible. */
6208 static tree
6211 {
6212 /* If this is the "or" of two comparisons, we can do something if
6213 the comparisons are NE_EXPR. If this is the "and", we can do something
6214 if the comparisons are EQ_EXPR. I.e.,
6215 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6217 WANTED_CODE is this operation code. For single bit fields, we can
6218 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6219 comparison for one-bit fields. */
6240 /* Start by getting the comparison codes. Fail if anything is volatile.
6241 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6242 it were surrounded with a NE_EXPR. */
6251 {
6255 }
6258 {
6262 }
6273 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6276 {
6279 {
6284 }
6287 {
6293 }
6294 }
6299 /* If the RHS can be evaluated unconditionally and its operands are
6300 simple, it wins to evaluate the RHS unconditionally on machines
6301 with expensive branches. In this case, this isn't a comparison
6302 that can be merged. */
6309 {
6310 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6321 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6331 }
6333 /* See if the comparisons can be merged. Then get all the parameters for
6334 each side. */
6359 /* It must be true that the inner operation on the lhs of each
6360 comparison must be the same if we are to be able to do anything.
6361 Then see if we have constants. If not, the same must be true for
6362 the rhs's. */
6371 {
6374 }
6379 else
6382 /* If either comparison code is not correct for our logical operation,
6383 fail. However, we can convert a one-bit comparison against zero into
6384 the opposite comparison against that bit being set in the field. */
6388 {
6390 {
6391 /* Make the left operand unsigned, since we are only interested
6392 in the value of one bit. Otherwise we are doing the wrong
6393 thing below. */
6396 }
6397 else
6399 }
6401 /* This is analogous to the code for l_const above. */
6403 {
6405 {
6408 }
6409 else
6411 }
6413 /* See if we can find a mode that contains both fields being compared on
6414 the left. If we can't, fail. Otherwise, update all constants and masks
6415 to be relative to a field of that size. */
6429 {
6432 }
6440 {
6447 {
6451 }
6452 }
6454 {
6461 {
6465 }
6466 }
6468 /* If the right sides are not constant, do the same for it. Also,
6469 disallow this optimization if a size, signedness or storage order
6470 mismatch occurs between the left and right sides. */
6472 {
6476 /* Make sure the two fields on the right
6477 correspond to the left without being swapped. */
6494 {
6497 }
6506 /* Make a mask that corresponds to both fields being compared.
6507 Do this for both items being compared. If the operands are the
6508 same size and the bits being compared are in the same position
6509 then we can do this by masking both and comparing the masked
6510 results. */
6517 {
6531 }
6533 /* There is still another way we can do something: If both pairs of
6534 fields being compared are adjacent, we may be able to make a wider
6535 field containing them both.
6537 Note that we still must mask the lhs/rhs expressions. Furthermore,
6538 the mask must be shifted to account for the shift done by
6539 make_bit_field_ref. */
6548 {
6549 tree type;
6565 /* Convert to the smaller type before masking out unwanted bits. */
6568 {
6570 {
6574 }
6576 {
6580 }
6581 }
6590 }
6593 }
6595 /* Handle the case of comparisons with constants. If there is something in
6596 common between the masks, those bits of the constants must be the same.
6597 If not, the condition is always false. Test for this to avoid generating
6598 incorrect code below. */
6603 {
6605 {
6608 }
6609 else
6610 {
6613 }
6614 }
6619 /* Construct the expression we will return. First get the component
6620 reference we will make. Unless the mask is all ones the width of
6621 that field, perform the mask operation. Then compare with the
6622 merged constant. */
6633 }
6634 \f
6635 /* T is an integer expression that is being multiplied, divided, or taken a
6636 modulus (CODE says which and what kind of divide or modulus) by a
6637 constant C. See if we can eliminate that operation by folding it with
6638 other operations already in T. WIDE_TYPE, if non-null, is a type that
6639 should be used for the computation if wider than our type.
6641 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6642 (X * 2) + (Y * 4). We must, however, be assured that either the original
6643 expression would not overflow or that overflow is undefined for the type
6644 in the language in question.
6646 If we return a non-null expression, it is an equivalent form of the
6647 original computation, but need not be in the original type.
6649 We set *STRICT_OVERFLOW_P to true if the return values depends on
6650 signed overflow being undefined. Otherwise we do not change
6651 *STRICT_OVERFLOW_P. */
6653 static tree
6656 {
6657 /* To avoid exponential search depth, refuse to allow recursion past
6658 three levels. Beyond that (1) it's highly unlikely that we'll find
6659 something interesting and (2) we've probably processed it before
6660 when we built the inner expression. */
6663 tree ret;
6668 depth++;
6670 depth--;
6673 }
6675 static tree
6678 {
6690 /* Don't deal with constants of zero here; they confuse the code below. */
6700 /* Note that we need not handle conditional operations here since fold
6701 already handles those cases. So just do arithmetic here. */
6703 {
6705 /* For a constant, we can always simplify if we are a multiply
6706 or (for divide and modulus) if it is a multiple of our constant. */
6710 {
6713 /* If the multiplication overflowed, we lost information on it.
6714 See PR68142 and PR69845. */
6718 }
6724 /* If op0 is an expression ... */
6730 /* ... and has wrapping overflow, and its type is smaller
6731 than ctype, then we cannot pass through as widening. */
6735 /* ... or this is a truncation (t is narrower than op0),
6736 then we cannot pass through this narrowing. */
6739 /* ... or signedness changes for division or modulus,
6740 then we cannot pass through this conversion. */
6744 /* ... or has undefined overflow while the converted to
6745 type has not, we cannot do the operation in the inner type
6746 as that would introduce undefined overflow. */
6751 /* Pass the constant down and see if we can make a simplification. If
6752 we can, replace this expression with the inner simplification for
6753 possible later conversion to our or some other type. */
6764 /* If widening the type changes it from signed to unsigned, then we
6765 must avoid building ABS_EXPR itself as unsigned. */
6767 {
6771 {
6774 }
6776 }
6777 /* If the constant is negative, we cannot simplify this. */
6780 /* FALLTHROUGH */
6782 /* For division and modulus, type can't be unsigned, as e.g.
6783 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6784 For signed types, even with wrapping overflow, this is fine. */
6793 /* If widening the type changes the signedness, then we can't perform
6794 this optimization as that changes the result. */
6798 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6804 {
6811 }
6815 /* If the second operand is constant, this is a multiplication
6816 or floor division, by a power of two, so we can treat it that
6817 way unless the multiplier or divisor overflows. Signed
6818 left-shift overflow is implementation-defined rather than
6819 undefined in C90, so do not convert signed left shift into
6820 multiplication. */
6823 /* const_binop may not detect overflow correctly,
6824 so check for it explicitly here. */
6833 ctype,
6835 t1),
6840 /* See if we can eliminate the operation on both sides. If we can, we
6841 can return a new PLUS or MINUS. If we can't, the only remaining
6842 cases where we can do anything are if the second operand is a
6843 constant. */
6850 /* If not multiplication, we can only do this if both operands
6851 are divisible by c. */
6854 {
6859 }
6861 /* If this was a subtraction, negate OP1 and set it to be an addition.
6862 This simplifies the logic below. */
6864 {
6866 /* If OP1 was not easily negatable, the constant may be OP0. */
6868 {
6871 }
6872 }
6877 /* If either OP1 or C are negative, this optimization is not safe for
6878 some of the division and remainder types while for others we need
6879 to change the code. */
6881 {
6889 }
6891 /* If it's a multiply or a division/modulus operation of a multiple
6892 of our constant, do the operation and verify it doesn't overflow. */
6896 {
6899 /* We allow the constant to overflow with wrapping semantics. */
6903 }
6904 else
6907 /* If we have an unsigned type, we cannot widen the operation since it
6908 will change the result if the original computation overflowed. */
6912 /* The last case is if we are a multiply. In that case, we can
6913 apply the distributive law to commute the multiply and addition
6914 if the multiplication of the constants doesn't overflow
6915 and overflow is defined. With undefined overflow
6916 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6917 But fold_plusminus_mult_expr would factor back any power-of-two
6918 value so do not distribute in the first place in this case. */
6926 op1);
6931 /* We have a special case here if we are doing something like
6932 (C * 8) % 4 since we know that's zero. */
6935 /* If the multiplication can overflow we cannot optimize this. */
6940 {
6943 }
6945 /* ... fall through ... */
6949 /* If we can extract our operation from the LHS, do so and return a
6950 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6951 do something only if the second operand is a constant. */
6967 /* If these are the same operation types, we can associate them
6968 assuming no overflow. */
6970 {
6985 }
6987 /* If these operations "cancel" each other, we have the main
6988 optimizations of this pass, which occur when either constant is a
6989 multiple of the other, in which case we replace this with either an
6990 operation or CODE or TCODE.
6992 If we have an unsigned type, we cannot do this since it will change
6993 the result if the original computation overflowed. */
7000 {
7003 {
7010 }
7013 {
7020 }
7021 }
7026 }
7029 }
7030 \f
7031 /* Return a node which has the indicated constant VALUE (either 0 or
7032 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7033 and is of the indicated TYPE. */
7035 tree
7037 {
7046 else
7048 }
7051 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7052 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7053 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7054 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7055 COND is the first argument to CODE; otherwise (as in the example
7056 given here), it is the second argument. TYPE is the type of the
7057 original expression. Return NULL_TREE if no simplification is
7058 possible. */
7060 static tree
7065 {
7073 /* Do not move possibly trapping operations into the conditional as this
7074 pessimizes code and causes gimplification issues when applied late. */
7082 {
7086 /* If this operand throws an expression, then it does not make
7087 sense to try to perform a logical or arithmetic operation
7088 involving it. */
7093 }
7096 {
7101 }
7102 else
7103 /* Detect the case of mixing vector and scalar types - bail out. */
7109 /* This transformation is only worthwhile if we don't have to wrap ARG
7110 in a SAVE_EXPR and the operation can be simplified without recursing
7111 on at least one of the branches once its pushed inside the COND_EXPR. */
7120 {
7124 else
7126 }
7128 {
7132 else
7134 }
7136 /* Check that we have simplified at least one of the branches. */
7141 }
7143 \f
7144 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7146 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7147 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7148 if ARG - ZERO_ARG is the same as X.
7150 If ARG is NULL, check for any value of type TYPE.
7152 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7153 and finite. The problematic cases are when X is zero, and its mode
7154 has signed zeros. In the case of rounding towards -infinity,
7155 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7156 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7158 bool
7161 {
7165 /* Don't allow the fold with -fsignaling-nans. */
7169 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7173 /* There is no case that is safe for all rounding modes. */
7177 /* In a vector or complex, we would need to check the sign of all zeros. */
7183 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7187 /* The mode has signed zeros, and we have to honor their sign.
7188 In this situation, there are only two cases we can return true for.
7189 (i) X - 0 is the same as X with default rounding.
7190 (ii) X + 0 is X when X can't possibly be -0.0. */
7192 }
7194 /* Subroutine of match.pd that optimizes comparisons of a division by
7195 a nonzero integer constant against an integer constant, i.e.
7196 X/C1 op C2.
7198 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7199 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7201 enum tree_code
7204 {
7209 /* We have to do this the hard way to detect unsigned overflow.
7210 prod = int_const_binop (MULT_EXPR, c1, c2); */
7216 {
7220 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7223 }
7225 {
7228 {
7247 }
7248 }
7249 else
7250 {
7251 /* A negative divisor reverses the relational operators. */
7256 {
7275 }
7276 }
7289 }
7292 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7293 equality/inequality test, then return a simplified form of the test
7294 using a sign testing. Otherwise return NULL. TYPE is the desired
7295 result type. */
7297 static tree
7300 tree result_type)
7301 {
7302 /* If this is testing a single bit, we can optimize the test. */
7306 {
7307 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7308 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7312 /* This is only a win if casting to a signed type is cheap,
7313 i.e. when arg00's type is not a partial mode. */
7315 {
7318 result_type,
7321 }
7322 }
7325 }
7327 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7328 equality/inequality test, then return a simplified form of
7329 the test using shifts and logical operations. Otherwise return
7330 NULL. TYPE is the desired result type. */
7332 tree
7335 {
7336 /* If this is testing a single bit, we can optimize the test. */
7340 {
7349 /* First, see if we can fold the single bit test into a sign-bit
7350 test. */
7352 result_type);
7356 /* Otherwise we have (A & C) != 0 where C is a single bit,
7357 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7358 Similarly for (A & C) == 0. */
7360 /* If INNER is a right shift of a constant and it plus BITNUM does
7361 not overflow, adjust BITNUM and INNER. */
7367 {
7370 }
7372 /* If we are going to be able to omit the AND below, we must do our
7373 operations as unsigned. If we must use the AND, we have a choice.
7374 Normally unsigned is faster, but for some machines signed is. */
7392 /* Put the AND last so it can combine with more things. */
7395 /* Make sure to return the proper type. */
7399 }
7401 }
7403 /* Test whether it is preferable to swap two operands, ARG0 and
7404 ARG1, for example because ARG0 is an integer constant and ARG1
7405 isn't. */
7407 bool
7409 {
7423 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7424 for commutative and comparison operators. Ensuring a canonical
7425 form allows the optimizers to find additional redundancies without
7426 having to explicitly check for both orderings. */
7432 /* Put SSA_NAMEs last. */
7438 /* Put variables last. */
7445 }
7448 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7449 means A >= Y && A != MAX, but in this case we know that
7450 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7452 static tree
7454 {
7461 else
7470 {
7473 }
7475 {
7478 }
7479 else
7486 {
7487 /* Convert the pointer types into integer before taking the difference. */
7491 }
7492 else
7499 }
7501 /* Fold a sum or difference of at least one multiplication.
7502 Returns the folded tree or NULL if no simplification could be made. */
7504 static tree
7507 {
7511 /* (A * C) +- (B * C) -> (A+-B) * C.
7512 (A * C) +- A -> A * (C+-1).
7513 We are most concerned about the case where C is a constant,
7514 but other combinations show up during loop reduction. Since
7515 it is not difficult, try all four possibilities. */
7518 {
7521 }
7523 {
7526 }
7527 else
7528 {
7529 /* We cannot generate constant 1 for fract. */
7534 }
7536 {
7539 }
7541 {
7543 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7544 the purpose of this canonicalization. */
7548 {
7551 }
7552 else
7554 }
7555 else
7556 {
7557 /* We cannot generate constant 1 for fract. */
7562 }
7565 /* Prefer factoring a common non-constant. */
7575 /* No identical multiplicands; see if we can find a common
7576 power-of-two factor in non-power-of-two multiplies. This
7577 can help in multi-dimensional array access. */
7579 {
7582 HOST_WIDE_INT tmp;
7584 tree maybe_same;
7586 /* Move min of absolute values to int11. */
7588 {
7593 }
7594 else
7601 /* The remainder should not be a constant, otherwise we
7602 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7603 increased the number of multiplications necessary. */
7605 {
7613 }
7614 }
7621 /* We are neither factoring zero nor minus one. */
7629 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7630 same may be minus one and thus the multiplication may overflow. Perform
7631 the sum operation in an unsigned type. */
7636 /* If the sum evaluated to a constant that is not -INF the multiplication
7637 cannot overflow. */
7644 /* Do not resort to unsigned multiplication because
7645 we lose the no-overflow property of the expression. */
7647 }
7649 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7650 specified by EXPR into the buffer PTR of length LEN bytes.
7651 Return the number of bytes placed in the buffer, or zero
7652 upon failure. */
7654 static int
7656 {
7668 /* Dry run. */
7674 {
7676 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7677 number of bytes. */
7681 {
7688 else
7690 }
7691 else
7695 }
7697 }
7700 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7701 specified by EXPR into the buffer PTR of length LEN bytes.
7702 Return the number of bytes placed in the buffer, or zero
7703 upon failure. */
7705 static int
7707 {
7711 FIXED_VALUE_TYPE value;
7726 }
7729 /* Subroutine of native_encode_expr. Encode the REAL_CST
7730 specified by EXPR into the buffer PTR of length LEN bytes.
7731 Return the number of bytes placed in the buffer, or zero
7732 upon failure. */
7734 static int
7736 {
7742 /* There are always 32 bits in each long, no matter the size of
7743 the hosts long. We handle floating point representations with
7744 up to 192 bits. */
7753 /* Dry run. */
7762 {
7767 {
7774 else
7776 }
7777 else
7778 {
7781 {
7782 /* Reverse bytes within each long, or within the entire float
7783 if it's smaller than a long (for HFmode). */
7786 }
7787 }
7792 }
7794 }
7796 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7797 specified by EXPR into the buffer PTR of length LEN bytes.
7798 Return the number of bytes placed in the buffer, or zero
7799 upon failure. */
7801 static int
7803 {
7805 tree part;
7819 }
7821 /* Like native_encode_vector, but only encode the first COUNT elements.
7822 The other arguments are as for native_encode_vector. */
7824 static int
7827 {
7831 {
7832 /* This is the only case in which elements can be smaller than a byte.
7833 Element 0 is always in the lsb of the containing byte. */
7842 /* Zero the buffer and then set bits later where necessary. */
7851 {
7857 {
7860 }
7861 }
7863 }
7868 {
7870 {
7873 }
7884 }
7886 }
7888 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7889 specified by EXPR into the buffer PTR of length LEN bytes.
7890 Return the number of bytes placed in the buffer, or zero
7891 upon failure. */
7893 static int
7895 {
7900 }
7903 /* Subroutine of native_encode_expr. Encode the STRING_CST
7904 specified by EXPR into the buffer PTR of length LEN bytes.
7905 Return the number of bytes placed in the buffer, or zero
7906 upon failure. */
7908 static int
7910 {
7913 /* Wide-char strings are encoded in target byte-order so native
7914 encoding them is trivial. */
7929 else
7930 {
7933 {
7936 }
7938 }
7940 }
7943 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
7944 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
7945 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
7946 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
7947 sufficient to encode the entire EXPR, or if OFF is out of bounds.
7948 Otherwise, start at byte offset OFF and encode at most LEN bytes.
7949 Return the number of bytes placed in the buffer, or zero upon failure. */
7951 int
7953 {
7954 /* We don't support starting at negative offset and -1 is special. */
7959 {
7980 }
7981 }
7983 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
7984 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
7985 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
7986 machine modes, we can't just use build_nonstandard_integer_type. */
7988 tree
7990 {
7991 machine_mode mode;
7993 {
8000 {
8004 }
8005 }
8011 {
8019 }
8022 }
8024 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8025 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8026 to be non-NULL and OFF zero), then in addition to filling the
8027 bytes pointed by PTR with the value also clear any bits pointed
8028 by MASK that are known to be initialized, keep them as is for
8029 e.g. uninitialized padding bits or uninitialized fields. */
8031 int
8034 {
8037 /* We don't support starting at negative offset and -1 is special. */
8045 {
8049 mask);
8064 {
8065 tree min_index;
8083 {
8088 {
8091 }
8096 else
8100 {
8104 offset_int wpos
8112 offset_int wcount
8119 }
8121 {
8124 offset_int wpos
8132 }
8135 {
8137 {
8148 }
8150 {
8154 }
8155 }
8159 do
8160 {
8165 {
8167 {
8170 fieldsize);
8173 }
8175 ptr
8178 fieldsize,
8181 mask
8185 else
8186 {
8189 }
8190 }
8193 {
8194 /* Partial overlap. */
8200 {
8204 fieldsize);
8205 }
8206 else
8207 {
8211 }
8214 }
8216 }
8218 }
8220 }
8223 {
8233 {
8239 {
8242 }
8245 {
8254 }
8258 else
8262 {
8263 tree fld;
8265 {
8278 }
8280 {
8284 }
8287 {
8288 cnt--;
8294 }
8295 }
8300 {
8313 {
8318 }
8319 }
8320 else
8321 {
8326 }
8331 {
8338 else
8344 }
8353 {
8354 /* FIXME: Handle PDP endian. */
8365 {
8368 }
8369 else
8370 {
8378 else
8379 {
8382 }
8383 }
8393 else
8406 /* If the bitfield does not start at byte boundary, handle
8407 the partial byte at the start. */
8410 {
8412 {
8417 {
8420 else
8422 }
8423 }
8424 else
8425 {
8430 {
8433 else
8437 }
8438 }
8439 }
8440 /* If the bitfield does not end at byte boundary, handle
8441 the partial byte at the end. */
8445 {
8447 {
8454 }
8455 else
8456 {
8463 }
8464 }
8468 {
8473 }
8474 else
8475 {
8476 /* Partial overlap. */
8480 {
8483 }
8487 }
8489 }
8494 {
8497 {
8500 {
8504 }
8507 }
8510 fldsize,
8520 }
8521 else
8522 {
8523 /* Partial overlap. */
8529 {
8533 fieldsize);
8534 }
8535 else
8536 {
8540 }
8543 }
8544 }
8546 }
8548 }
8549 }
8552 /* Subroutine of native_interpret_expr. Interpret the contents of
8553 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8554 If the buffer cannot be interpreted, return NULL_TREE. */
8556 static tree
8558 {
8568 }
8571 /* Subroutine of native_interpret_expr. Interpret the contents of
8572 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8573 If the buffer cannot be interpreted, return NULL_TREE. */
8575 static tree
8577 {
8580 double_int result;
8581 FIXED_VALUE_TYPE fixed_value;
8591 }
8594 /* Subroutine of native_interpret_expr. Interpret the contents of
8595 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8596 If the buffer cannot be interpreted, return NULL_TREE. */
8598 static tree
8600 {
8604 /* There are always 32 bits in each long, no matter the size of
8605 the hosts long. We handle floating point representations with
8606 up to 192 bits. */
8607 REAL_VALUE_TYPE r;
8617 {
8618 /* Both OFFSET and BYTE index within a long;
8619 bitpos indexes the whole float. */
8622 {
8629 else
8631 }
8632 else
8633 {
8636 {
8637 /* Reverse bytes within each long, or within the entire float
8638 if it's smaller than a long (for HFmode). */
8641 }
8642 }
8646 }
8651 {
8652 /* For floating point values in composite modes, punt if this folding
8653 doesn't preserve bit representation. As the mode doesn't have fixed
8654 precision while GCC pretends it does, there could be valid values that
8655 GCC can't really represent accurately. See PR95450. */
8660 }
8662 }
8665 /* Subroutine of native_interpret_expr. Interpret the contents of
8666 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8667 If the buffer cannot be interpreted, return NULL_TREE. */
8669 static tree
8671 {
8686 }
8688 /* Read a vector of type TYPE from the target memory image given by BYTES,
8689 which contains LEN bytes. The vector is known to be encodable using
8690 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8692 Return the vector on success, otherwise return null. */
8694 static tree
8698 {
8702 {
8703 /* This is the only case in which elements can be smaller than a byte.
8704 Element 0 is always in the lsb of the containing byte. */
8711 {
8718 }
8720 }
8728 {
8734 }
8736 }
8738 /* Subroutine of native_interpret_expr. Interpret the contents of
8739 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8740 If the buffer cannot be interpreted, return NULL_TREE. */
8742 static tree
8744 {
8745 tree etype;
8756 }
8759 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8760 the buffer PTR of length LEN as a constant of type TYPE. For
8761 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8762 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8763 return NULL_TREE. */
8765 tree
8767 {
8769 {
8791 }
8792 }
8794 /* Returns true if we can interpret the contents of a native encoding
8795 as TYPE. */
8797 bool
8799 {
8801 {
8814 }
8815 }
8817 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8818 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8820 tree
8823 {
8826 {
8833 {
8837 }
8842 {
8847 {
8852 }
8856 eltsz);
8860 }
8862 }
8866 {
8874 {
8877 {
8878 poly_int64 bitoffset;
8883 else
8893 }
8894 else
8895 {
8913 HOST_WIDE_INT rpos;
8916 else
8917 {
8920 }
8929 }
8930 }
8933 {
8943 }
8947 {
8952 }
8959 {
8963 /* FIXME: Figure out how to handle PDP endian bitfields. */
8969 else
8973 }
8975 }
8977 }
8979 /* Routines for manipulation of native_encode_expr encoded data if the encoded
8980 or extracted constant positions and/or sizes aren't byte aligned. */
8982 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
8983 bits between adjacent elements. AMNT should be within
8984 [0, BITS_PER_UNIT).
8985 Example, AMNT = 2:
8986 00011111|11100000 << 2 = 01111111|10000000
8987 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
8989 void
8992 {
9001 {
9007 {
9010 }
9011 }
9012 }
9014 /* Like shift_bytes_in_array_left but for big-endian.
9015 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9016 bits between adjacent elements. AMNT should be within
9017 [0, BITS_PER_UNIT).
9018 Example, AMNT = 2:
9019 00011111|11100000 >> 2 = 00000111|11111000
9020 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9022 void
9025 {
9033 {
9040 }
9041 }
9043 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9044 directly on the VECTOR_CST encoding, in a way that works for variable-
9045 length vectors. Return the resulting VECTOR_CST on success or null
9046 on failure. */
9048 static tree
9050 {
9062 /* We can only preserve the semantics of a stepped pattern if the new
9063 vector element is an integer of the same size. */
9068 /* The number of bits needed to encode one element from every pattern
9069 of the original vector. */
9070 unsigned int expr_sequence_bits
9073 /* The number of bits needed to encode one element from every pattern
9074 of the result. */
9075 unsigned int type_sequence_bits
9078 /* Don't try to read more bytes than are available, which can happen
9079 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9080 The general VIEW_CONVERT handling can cope with that case, so there's
9081 no point complicating things here. */
9084 BITS_PER_UNIT);
9089 /* Get enough bytes of EXPR to form the new encoding. */
9097 /* Reencode the bytes as TYPE. */
9101 }
9103 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9104 TYPE at compile-time. If we're unable to perform the conversion
9105 return NULL_TREE. */
9107 static tree
9109 {
9110 /* We support up to 512-bit values (for V8DFmode). */
9114 /* Check that the host and target are sane. */
9127 }
9129 /* Build an expression for the address of T. Folds away INDIRECT_REF
9130 to avoid confusing the gimplify process. */
9132 tree
9134 {
9135 /* The size of the object is not relevant when talking about its address. */
9140 {
9145 }
9148 {
9153 }
9160 {
9165 }
9166 else
9170 }
9172 /* Build an expression for the address of T. */
9174 tree
9176 {
9180 }
9182 /* Fold a unary expression of code CODE and type TYPE with operand
9183 OP0. Return the folded expression if folding is successful.
9184 Otherwise, return NULL_TREE. */
9186 tree
9188 {
9189 tree tem;
9190 tree arg0;
9198 {
9201 {
9202 /* Don't use STRIP_NOPS, because signedness of argument type
9203 matters. */
9205 }
9206 else
9207 {
9208 /* Strip any conversions that don't change the mode. This
9209 is safe for every expression, except for a comparison
9210 expression because its signedness is derived from its
9211 operands.
9213 Note that this is done as an internal manipulation within
9214 the constant folder, in order to find the simplest
9215 representation of the arguments so that their form can be
9216 studied. In any cases, the appropriate type conversions
9217 should be put back in the tree that will get out of the
9218 constant folder. */
9220 }
9223 {
9226 {
9230 }
9231 }
9232 }
9239 {
9246 {
9260 /* If this was a conversion, and all we did was to move into
9261 inside the COND_EXPR, bring it back out. But leave it if
9262 it is a conversion from integer to integer and the
9263 result precision is no wider than a word since such a
9264 conversion is cheap and may be optimized away by combine,
9265 while it couldn't if it were outside the COND_EXPR. Then return
9266 so we don't get into an infinite recursion loop taking the
9267 conversion out and then back in. */
9279 && (INTEGRAL_TYPE_P
9292 }
9293 }
9296 {
9302 CASE_CONVERT:
9306 {
9307 /* If we have (type) (a CMP b) and type is an integral type, return
9308 new expression involving the new type. Canonicalize
9309 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9310 non-integral type.
9311 Do not fold the result as that would not simplify further, also
9312 folding again results in recursions. */
9322 }
9324 /* Handle (T *)&A.B.C for A being of type T and B and C
9325 living at offset zero. This occurs frequently in
9326 C++ upcasting and then accessing the base. */
9330 {
9332 tree offset;
9333 machine_mode mode;
9335 tree base
9339 /* If the reference was to a (constant) zero offset, we can use
9340 the address of the base if it has the same base type
9341 as the result type and the pointer type is unqualified. */
9349 }
9353 /* Detect assigning a bitfield. */
9355 && DECL_BIT_FIELD
9357 {
9358 /* Don't leave an assignment inside a conversion
9359 unless assigning a bitfield. */
9361 /* First do the assignment, then return converted constant. */
9366 }
9368 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9369 constants (if x has signed type, the sign bit cannot be set
9370 in c). This folds extension into the BIT_AND_EXPR.
9371 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9372 very likely don't have maximal range for their precision and this
9373 transformation effectively doesn't preserve non-maximal ranges. */
9377 {
9388 <= HOST_BITS_PER_WIDE_INT
9390 {
9394 cst &= HOST_WIDE_INT_M1U
9398 && !flag_syntax_only
9401 {
9405 }
9406 }
9408 {
9413 }
9414 }
9416 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9417 cast (T1)X will fold away. We assume that this happens when X itself
9418 is a cast. */
9422 {
9426 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9427 when the pointed type needs higher alignment than
9428 the p+ first operand's pointed type. */
9437 }
9439 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9440 of the same precision, and X is an integer type not narrower than
9441 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9447 {
9453 }
9455 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9456 type of X and Y (integer types only). */
9461 {
9462 /* Be careful not to introduce new overflows. */
9463 tree mult_type;
9466 else
9470 {
9477 }
9478 }
9484 {
9491 }
9502 /* Convert fabs((double)float) into (double)fabsf(float). */
9505 {
9511 targ0));
9512 }
9516 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9535 /* Note that the operand of this must be an int
9536 and its values must be 0 or 1.
9537 ("true" is a fixed value perhaps depending on the language,
9538 but we don't handle values other than 1 correctly yet.) */
9545 /* Fold *&X to X if X is an lvalue. */
9547 {
9554 }
9560 }
9563 /* If the operation was a conversion do _not_ mark a resulting constant
9564 with TREE_OVERFLOW if the original constant was not. These conversions
9565 have implementation defined behavior and retaining the TREE_OVERFLOW
9566 flag here would confuse later passes such as VRP. */
9567 tree
9570 {
9579 }
9581 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9582 operands OP0 and OP1. LOC is the location of the resulting expression.
9583 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9584 Return the folded expression if folding is successful. Otherwise,
9585 return NULL_TREE. */
9586 static tree
9589 {
9590 tree tem;
9592 /* We only do these simplifications if we are optimizing. */
9596 /* Check for things like (A || B) && (A || C). We can convert this
9597 to A || (B && C). Note that either operator can be any of the four
9598 truth and/or operations and the transformation will still be
9599 valid. Also note that we only care about order for the
9600 ANDIF and ORIF operators. If B contains side effects, this
9601 might change the truth-value of A. */
9608 {
9628 /* This case if tricky because we must either have commutative
9629 operators or else A10 must not have side-effects. */
9635 a01);
9636 }
9638 /* See if we can build a range comparison. */
9644 {
9648 }
9652 {
9656 }
9658 /* Check for the possibility of merging component references. If our
9659 lhs is another similar operation, try to merge its rhs with our
9660 rhs. Then try to merge our lhs and rhs. */
9671 logical_op_non_short_circuit
9679 {
9686 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9687 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9688 We don't want to pack more than two leafs to a non-IF AND/OR
9689 expression.
9690 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9691 equal to IF-CODE, then we don't want to add right-hand operand.
9692 If the inner right-hand side of left-hand operand has
9693 side-effects, or isn't simple, then we can't add to it,
9694 as otherwise we might destroy if-sequence. */
9697 /* Needed for sequence points to handle trappings, and
9698 side-effects. */
9700 {
9702 arg1);
9704 tem);
9705 }
9706 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9707 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9710 /* Needed for sequence points to handle trappings, and
9711 side-effects. */
9713 {
9718 }
9719 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9720 into (A OR B).
9721 For sequence point consistancy, we need to check for trapping,
9722 and side-effects. */
9726 }
9729 }
9731 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9732 by changing CODE to reduce the magnitude of constants involved in
9733 ARG0 of the comparison.
9734 Returns a canonicalized comparison tree if a simplification was
9735 possible, otherwise returns NULL_TREE.
9736 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9737 valid if signed overflow is undefined. */
9739 static tree
9743 {
9748 /* Match A +- CST code arg1. We can change this only if overflow
9749 is undefined. */
9752 /* In principle pointers also have undefined overflow behavior,
9753 but that causes problems elsewhere. */
9760 /* Identify the constant in arg0 and its sign. */
9764 /* Overflowed constants and zero will cause problems. */
9769 /* See if we can reduce the magnitude of the constant in
9770 arg0 by changing the comparison code. */
9771 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9775 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9779 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9783 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9787 else
9791 /* Now build the constant reduced in magnitude. But not if that
9792 would produce one outside of its types range. */
9808 }
9810 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9811 overflow further. Try to decrease the magnitude of constants involved
9812 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9813 and put sole constants at the second argument position.
9814 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9816 static tree
9819 {
9820 tree t;
9825 /* Try canonicalization by simplifying arg0. */
9830 {
9834 }
9836 /* Try canonicalization by simplifying arg1 using the swapped
9837 comparison. */
9845 }
9847 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9848 space. This is used to avoid issuing overflow warnings for
9849 expressions like &p->x which cannot wrap. */
9851 static bool
9853 {
9860 poly_wide_int wi_offset;
9866 else
9871 precision);
9886 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9887 array. */
9896 }
9898 /* Return a positive integer when the symbol DECL is known to have
9899 a nonzero address, zero when it's known not to (e.g., it's a weak
9900 symbol), and a negative integer when the symbol is not yet in the
9901 symbol table and so whether or not its address is zero is unknown.
9902 For function local objects always return positive integer. */
9903 static int
9905 {
9910 /* Function local objects are never NULL. */
9918 }
9920 /* Subroutine of fold_binary. This routine performs all of the
9921 transformations that are common to the equality/inequality
9922 operators (EQ_EXPR and NE_EXPR) and the ordering operators
9923 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
9924 fold_binary should call fold_binary. Fold a comparison with
9925 tree code CODE and type TYPE with operands OP0 and OP1. Return
9926 the folded comparison or NULL_TREE. */
9928 static tree
9931 {
9941 /* For comparisons of pointers we can decompose it to a compile time
9942 comparison of the base objects and the offsets into the object.
9943 This requires at least one operand being an ADDR_EXPR or a
9944 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
9950 {
9953 machine_mode mode;
9957 /* Get base and offset for the access. Strip ADDR_EXPR for
9958 get_inner_reference, but put it back by stripping INDIRECT_REF
9959 off the base object if possible. indirect_baseN will be true
9960 if baseN is not an address but refers to the object itself. */
9963 {
9964 base0
9970 else
9972 }
9974 {
9978 {
9979 base0
9985 else
9987 }
9990 else
9994 {
10001 }
10002 }
10006 {
10007 base1
10013 else
10015 }
10017 {
10021 {
10022 base1
10028 else
10030 }
10033 else
10037 {
10044 }
10045 }
10047 /* If we have equivalent bases we might be able to simplify. */
10051 {
10052 /* We can fold this expression to a constant if the non-constant
10053 offset parts are equal. */
10057 && (equality_code
10058 || (indirect_base0
10061 {
10067 "occur when comparing P +- C1 with "
10069 WARN_STRICT_OVERFLOW_CONDITIONAL);
10072 {
10110 }
10111 }
10112 /* We can simplify the comparison to a comparison of the variable
10113 offset parts if the constant offset parts are equal.
10114 Be careful to use signed sizetype here because otherwise we
10115 mess with array offsets in the wrong way. This is possible
10116 because pointer arithmetic is restricted to retain within an
10117 object and overflow on pointer differences is undefined as of
10118 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10120 && (equality_code
10121 || (indirect_base0
10124 {
10125 /* By converting to signed sizetype we cover middle-end pointer
10126 arithmetic which operates on unsigned pointer types of size
10127 type size and ARRAY_REF offsets which are properly sign or
10128 zero extended from their type in case it is narrower than
10129 sizetype. */
10132 else
10136 else
10143 "occur when comparing P +- C1 with "
10145 WARN_STRICT_OVERFLOW_COMPARISON);
10148 }
10149 }
10150 /* For equal offsets we can simplify to a comparison of the
10151 base addresses. */
10153 && (indirect_base0
10155 && (indirect_base1
10160 {
10166 }
10167 /* Comparison between an ordinary (non-weak) symbol and a null
10168 pointer can be eliminated since such symbols must have a non
10169 null address. In C, relational expressions between pointers
10170 to objects and null pointers are undefined. The results
10171 below follow the C++ rules with the additional property that
10172 every object pointer compares greater than a null pointer.
10173 */
10176 /* Avoid folding references to struct members at offset 0 to
10177 prevent tests like '&ptr->firstmember == 0' from getting
10178 eliminated. When ptr is null, although the -> expression
10179 is strictly speaking invalid, GCC retains it as a matter
10180 of QoI. See PR c/44555. */
10183 && indirect_base0
10184 /* The caller guarantees that when one of the arguments is
10185 constant (i.e., null in this case) it is second. */
10187 {
10189 {
10200 }
10201 }
10202 }
10204 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10205 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10206 the resulting offset is smaller in absolute value than the
10207 original one and has the same sign. */
10216 {
10221 tree cst;
10223 "occur when combining constants around "
10226 /* Put the constant on the side where it doesn't overflow and is
10227 of lower absolute value and of same sign than before. */
10234 {
10237 variable1,
10241 }
10249 {
10255 variable2);
10256 }
10257 }
10263 /* If we are comparing an expression that just has comparisons
10264 of two integer values, arithmetic expressions of those comparisons,
10265 and constants, we can simplify it. There are only three cases
10266 to check: the two values can either be equal, the first can be
10267 greater, or the second can be greater. Fold the expression for
10268 those three values. Since each value must be 0 or 1, we have
10269 eight possibilities, each of which corresponds to the constant 0
10270 or 1 or one of the six possible comparisons.
10272 This handles common cases like (a > b) == 0 but also handles
10273 expressions like ((x > y) - (y > x)) > 0, which supposedly
10274 occur in macroized code. */
10277 {
10281 /* Don't handle degenerate cases here; they should already
10282 have been handled anyway. */
10291 {
10295 /* We can't just pass T to eval_subst in case cval1 or cval2
10296 was the same as ARG1. */
10298 tree high_result
10302 arg1);
10303 tree equal_result
10307 arg1);
10308 tree low_result
10312 arg1);
10314 /* All three of these results should be 0 or 1. Confirm they are.
10315 Then use those values to select the proper code to use. */
10320 {
10321 /* Make a 3-bit mask with the high-order bit being the
10322 value for `>', the next for '=', and the low for '<'. */
10326 {
10328 /* Always false. */
10349 /* Always true. */
10351 }
10354 }
10355 }
10356 }
10359 }
10362 /* Subroutine of fold_binary. Optimize complex multiplications of the
10363 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10364 argument EXPR represents the expression "z" of type TYPE. */
10366 static tree
10368 {
10373 {
10376 }
10378 {
10381 }
10382 else
10383 {
10387 }
10396 }
10399 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10400 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10401 true if successful. */
10403 static bool
10405 {
10410 {
10413 }
10415 {
10421 else
10423 }
10424 else
10430 }
10432 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10433 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10434 NULL_TREE otherwise. */
10436 tree
10438 {
10459 {
10460 HOST_WIDE_INT index;
10466 }
10469 {
10475 }
10476 else
10478 }
10480 /* Try to fold a pointer difference of type TYPE two address expressions of
10481 array references AREF0 and AREF1 using location LOC. Return a
10482 simplified expression for the difference or NULL_TREE. */
10484 static tree
10488 {
10493 /* If the bases are array references as well, recurse. If the bases
10494 are pointer indirections compute the difference of the pointers.
10495 If the bases are equal, we are set. */
10498 && (base_offset
10500 use_pointer_diff)))
10503 && (base_offset
10504 = use_pointer_diff
10514 {
10520 base_offset,
10523 }
10525 }
10527 /* If the real or vector real constant CST of type TYPE has an exact
10528 inverse, return it, else return NULL. */
10530 tree
10532 {
10533 REAL_VALUE_TYPE r;
10534 tree unit_type;
10535 machine_mode mode;
10538 {
10548 {
10552 tree_vector_builder elts;
10557 {
10562 }
10565 }
10569 }
10570 }
10572 /* Mask out the tz least significant bits of X of type TYPE where
10573 tz is the number of trailing zeroes in Y. */
10574 static wide_int
10576 {
10581 }
10583 /* Return true when T is an address and is known to be nonzero.
10584 For floating point we further ensure that T is not denormal.
10585 Similar logic is present in nonzero_address in rtlanal.h.
10587 If the return value is based on the assumption that signed overflow
10588 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10589 change *STRICT_OVERFLOW_P. */
10591 static bool
10593 {
10597 /* Doing something useful for floating point would need more work. */
10603 {
10606 strict_overflow_p);
10612 strict_overflow_p);
10620 }
10623 {
10626 strict_overflow_p);
10634 strict_overflow_p);
10649 strict_overflow_p);
10653 strict_overflow_p);
10656 {
10668 }
10672 }
10674 }
10676 /* Return true when T is an address and is known to be nonzero.
10677 Handle warnings about undefined signed overflow. */
10679 bool
10681 {
10688 "determining that expression is always "
10690 WARN_STRICT_OVERFLOW_MISC);
10692 }
10694 /* Return true if T is known not to be equal to an integer W. */
10696 bool
10698 {
10699 value_range vr;
10701 {
10711 else
10717 /* If T has some known zero bits and W has any of those bits set,
10718 then T is known not to be equal to W. */
10726 }
10727 }
10729 /* Fold a binary expression of code CODE and type TYPE with operands
10730 OP0 and OP1. LOC is the location of the resulting expression.
10731 Return the folded expression if folding is successful. Otherwise,
10732 return NULL_TREE. */
10734 tree
10737 {
10752 /* Strip any conversions that don't change the mode. This is
10753 safe for every expression, except for a comparison expression
10754 because its signedness is derived from its operands. So, in
10755 the latter case, only strip conversions that don't change the
10756 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10757 preserved.
10759 Note that this is done as an internal manipulation within the
10760 constant folder, in order to find the simplest representation
10761 of the arguments so that their form can be studied. In any
10762 cases, the appropriate type conversions should be put back in
10763 the tree that will get out of the constant folder. */
10766 {
10769 }
10770 else
10771 {
10774 }
10776 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10777 constant but we can't do arithmetic on them. */
10779 {
10782 {
10786 }
10787 }
10789 /* If this is a commutative operation, and ARG0 is a constant, move it
10790 to ARG1 to reduce the number of tests below. */
10795 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10796 to ARG1 to reduce the number of tests below. */
10805 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10807 First check for cases where an arithmetic operation is applied to a
10808 compound, conditional, or comparison operation. Push the arithmetic
10809 operation inside the compound or conditional to see if any folding
10810 can then be done. Convert comparison to conditional for this purpose.
10811 The also optimizes non-constant cases that used to be done in
10812 expand_expr.
10814 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10815 one of the operands is a comparison and the other is a comparison, a
10816 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10817 code below would make the expression more complex. Change it to a
10818 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10819 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10832 {
10836 boolean_type_node,
10844 }
10848 {
10850 {
10855 tem);
10856 }
10858 {
10863 tem);
10864 }
10869 {
10875 }
10880 {
10886 }
10887 }
10890 {
10892 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10895 {
10901 }
10903 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10906 {
10907 tree base;
10908 poly_int64 coffset;
10917 }
10922 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
10928 arg1),
10930 arg0)));
10936 {
10937 /* X + (X / CST) * -CST is X % CST. */
10942 {
10951 cst0));
10952 }
10953 }
10955 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
10956 one. Make sure the type is not saturating and has the signedness of
10957 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10958 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10965 {
10969 }
10972 {
10973 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
10974 (plus (plus (mult) (mult)) (foo)) so that we can
10975 take advantage of the factoring cases below. */
10984 {
10990 else
11003 parg0),
11005 marg)),
11009 return
11015 parg1)));
11016 }
11017 }
11018 else
11019 {
11020 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11021 to __complex__ ( x, y ). This is not the same for SNaNs or
11022 if signed zeros are involved. */
11026 {
11033 {
11037 {
11043 }
11045 {
11051 }
11052 }
11053 }
11055 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11056 We associate floats only if the user has specified
11057 -fassociative-math. */
11061 {
11066 {
11067 tree tree0;
11070 }
11071 }
11072 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11073 We associate floats only if the user has specified
11074 -fassociative-math. */
11078 {
11083 {
11084 tree tree0;
11087 }
11088 }
11089 }
11091 bit_rotate:
11092 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11093 is a rotate of A by C1 bits. */
11094 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11095 is a rotate of A by B bits.
11096 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11097 though in this case CODE must be | and not + or ^, otherwise
11098 it doesn't return A when B is 0. */
11099 {
11101 tree rtype;
11110 /* Only create rotates in complete modes. Other cases are not
11111 expanded properly. */
11114 {
11127 {
11132 }
11137 {
11140 code0 == LSHIFT_EXPR
11143 }
11145 {
11155 {
11159 orig_tree01);
11161 }
11162 }
11166 {
11177 {
11181 orig_tree01);
11183 }
11184 }
11185 }
11186 }
11188 associate:
11189 /* In most languages, can't associate operations on floats through
11190 parentheses. Rather than remember where the parentheses were, we
11191 don't associate floats at all, unless the user has specified
11192 -fassociative-math.
11193 And, we need to make sure type is not saturating. */
11197 {
11203 /* Split both trees into variables, constants, and literals. Then
11204 associate each group together, the constants with literals,
11205 then the result with variables. This increases the chances of
11206 literals being recombined later and of generating relocatable
11207 expressions for the sum of a constant and literal. */
11215 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11219 /* With undefined overflow prefer doing association in a type
11220 which wraps on overflow, if that is one of the operand types. */
11223 {
11231 }
11233 /* With undefined overflow we can only associate constants with one
11234 variable, and constants whose association doesn't overflow. */
11237 {
11239 {
11240 /* ??? If split_tree would handle NEGATE_EXPR we could
11241 simply reject these cases and the allowed cases would
11242 be the var0/minus_var1 ones. */
11248 {
11251 }
11258 {
11261 }
11267 /* The only case we can still associate with two variables
11268 is if they cancel out. */
11272 }
11278 }
11280 /* Only do something if we found more than two objects. Otherwise,
11281 nothing has changed and we risk infinite recursion. */
11289 {
11301 {
11305 }
11307 {
11311 }
11313 /* Preserve the MINUS_EXPR if the negative part of the literal is
11314 greater than the positive part. Otherwise, the multiplicative
11315 folding code (i.e extract_muldiv) may be fooled in case
11316 unsigned constants are subtracted, like in the following
11317 example: ((X*2 + 4) - 8U)/2. */
11319 {
11323 /* But avoid ending up with only negated parts. */
11325 {
11329 }
11330 else
11331 {
11335 }
11336 }
11338 /* Don't introduce overflows through reassociation. */
11343 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11350 /* Eliminate minus_con0. */
11352 {
11359 else
11362 }
11364 /* Eliminate minus_var0. */
11366 {
11370 else
11373 }
11375 return
11378 }
11379 }
11385 /* Fold &a[i] - &a[j] to i-j. */
11390 {
11394 code
11398 }
11400 /* Further transformations are not for pointers. */
11404 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11407 /* If arg0 is e.g. unsigned int and type is int, then this could
11408 introduce UB, because if A is INT_MIN at runtime, the original
11409 expression can be well defined while the latter is not.
11410 See PR83269. */
11419 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11420 __complex__ ( x, -y ). This is not the same for SNaNs or if
11421 signed zeros are involved. */
11425 {
11432 {
11436 {
11438 arg1r ? arg1r
11443 }
11445 {
11449 arg1i ? arg1i
11452 }
11453 }
11454 }
11456 /* A - B -> A + (-B) if B is easily negatable. */
11460 /* Avoid this transformation if B is a positive REAL_CST. */
11468 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11469 one. Make sure the type is not saturating and has the signedness of
11470 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11471 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11478 {
11482 }
11488 {
11489 /* Transform x * -C into -x * C if x is easily negatable. */
11504 {
11507 "occur when simplifying "
11509 WARN_STRICT_OVERFLOW_MISC);
11511 }
11513 /* Optimize z * conj(z) for integer complex numbers. */
11520 }
11521 else
11522 {
11523 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11524 This is not the same for NaNs or if signed zeros are
11525 involved. */
11531 {
11534 return
11540 return
11545 }
11547 /* Optimize z * conj(z) for floating point complex numbers.
11548 Guarded by flag_unsafe_math_optimizations as non-finite
11549 imaginary components don't produce scalar results. */
11558 }
11562 /* Canonicalize (X & C1) | C2. */
11566 {
11571 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11579 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11581 {
11584 }
11586 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11587 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11588 mode which allows further optimizations. */
11593 {
11598 {
11601 }
11602 }
11605 {
11610 }
11611 }
11613 /* See if this can be simplified into a rotate first. If that
11614 is unsuccessful continue in the association code. */
11618 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11626 /* See if this can be simplified into a rotate first. If that
11627 is unsuccessful continue in the association code. */
11631 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11636 {
11637 tree tem2;
11644 }
11645 /* Fold ~X & 1 as (X & 1) == 0. */
11649 {
11650 tree tem2;
11657 }
11658 /* Fold !X & 1 as X == 0. */
11661 {
11665 }
11667 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11668 multiple of 1 << CST. */
11670 {
11677 }
11679 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11680 bits from CST2. */
11684 {
11686 wide_int masked
11693 {
11694 /* Avoid the transform if arg1 is a mask of some
11695 mode which allows further optimizations. */
11702 }
11703 }
11705 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11708 {
11713 return
11715 }
11720 /* Don't touch a floating-point divide by zero unless the mode
11721 of the constant can represent infinity. */
11727 /* (-A) / (-B) -> A / B */
11739 /* Fall through */
11742 /* Simplify A / (B << N) where A and B are positive and B is
11743 a power of 2, to A >> (N + log2(B)). */
11748 {
11751 {
11759 WARN_STRICT_OVERFLOW_MISC);
11765 }
11766 }
11768 /* Fall through */
11776 /* Convert -A / -B to A / B when the type is signed and overflow is
11777 undefined. */
11781 {
11784 "when distributing negation across "
11786 WARN_STRICT_OVERFLOW_MISC);
11791 }
11795 {
11798 "when distributing negation across "
11800 WARN_STRICT_OVERFLOW_MISC);
11805 }
11807 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11808 operation, EXACT_DIV_EXPR.
11810 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11811 At one time others generated faster code, it's not clear if they do
11812 after the last round to changes to the DIV code in expmed.c. */
11823 {
11827 WARN_STRICT_OVERFLOW_MISC);
11829 }
11841 {
11845 WARN_STRICT_OVERFLOW_MISC);
11847 }
11855 /* Since negative shift count is not well-defined,
11856 don't try to compute it in the compiler. */
11862 /* If we have a rotate of a bit operation with the rotate count and
11863 the second operand of the bit operation both constant,
11864 permute the two operations. */
11870 {
11878 }
11880 /* Two consecutive rotates adding up to the some integer
11881 multiple of the precision of the type can be ignored. */
11897 /* Note that the operands of this must be ints
11898 and their values must be 0 or 1.
11899 ("true" is a fixed value perhaps depending on the language.) */
11900 /* If first arg is constant zero, return it. */
11903 /* FALLTHRU */
11905 /* If either arg is constant true, drop it. */
11909 /* Preserve sequence points. */
11912 /* If second arg is constant zero, result is zero, but first arg
11913 must be evaluated. */
11916 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11917 case will be handled here. */
11921 /* !X && X is always false. */
11925 /* X && !X is always false. */
11930 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11931 means A >= Y && A != MAX, but in this case we know that
11932 A < X <= MAX. */
11936 {
11944 }
11953 /* Note that the operands of this must be ints
11954 and their values must be 0 or true.
11955 ("true" is a fixed value perhaps depending on the language.) */
11956 /* If first arg is constant true, return it. */
11959 /* FALLTHRU */
11961 /* If either arg is constant zero, drop it. */
11965 /* Preserve sequence points. */
11968 /* If second arg is constant true, result is true, but we must
11969 evaluate first arg. */
11972 /* Likewise for first arg, but note this only occurs here for
11973 TRUTH_OR_EXPR. */
11977 /* !X || X is always true. */
11981 /* X || !X is always true. */
11986 /* (X && !Y) || (!X && Y) is X ^ Y */
11989 {
12006 }
12015 /* If the second arg is constant zero, drop it. */
12018 /* If the second arg is constant true, this is a logical inversion. */
12020 {
12023 }
12024 /* Identical arguments cancel to zero. */
12028 /* !X ^ X is always true. */
12033 /* X ^ !X is always true. */
12049 /* bool_var != 1 becomes !bool_var. */
12056 /* bool_var == 0 becomes !bool_var. */
12063 /* !exp != 0 becomes !exp */
12068 /* If this is an EQ or NE comparison with zero and ARG0 is
12069 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12070 two operations, but the latter can be done in one less insn
12071 on machines that have only two-operand insns or on which a
12072 constant cannot be the first operand. */
12075 {
12080 {
12088 }
12091 {
12099 }
12100 }
12102 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12103 C1 is a valid shift constant, and C2 is a power of two, i.e.
12104 a single bit. */
12108 {
12113 {
12118 /* Check for a valid shift count. */
12120 {
12124 /* If (C2 << C1) doesn't overflow, then
12125 ((X >> C1) & C2) != 0 can be rewritten as
12126 (X & (C2 << C1)) != 0. */
12128 {
12135 }
12136 /* Otherwise, for signed (arithmetic) shifts,
12137 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12138 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12144 /* Otherwise, of unsigned (logical) shifts,
12145 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12146 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12147 else
12151 arg000);
12152 }
12153 }
12154 }
12156 /* If this is a comparison of a field, we may be able to simplify it. */
12159 /* Handle the constant case even without -O
12160 to make sure the warnings are given. */
12162 {
12166 }
12168 /* Optimize comparisons of strlen vs zero to a compare of the
12169 first character of the string vs zero. To wit,
12170 strlen(ptr) == 0 => *ptr == 0
12171 strlen(ptr) != 0 => *ptr != 0
12172 Other cases should reduce to one of these two (or a constant)
12173 due to the return value of strlen being unsigned. */
12175 {
12183 {
12184 tree ptrtype
12186 TYPE_QUAL_CONST));
12192 }
12193 }
12195 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12196 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12200 {
12205 {
12207 {
12210 }
12213 }
12214 }
12216 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12217 (X & C) == 0 when C is a single bit. */
12222 {
12229 arg1));
12230 }
12232 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12233 constant C is a power of two, i.e. a single bit. */
12240 {
12244 }
12246 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12247 when is C is a power of two, i.e. a single bit. */
12254 {
12260 }
12264 {
12267 }
12271 {
12278 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12279 operand_equal_p guarantees no side-effects so we don't need
12280 to use omit_one_operand on Z. */
12284 arg10));
12288 arg11));
12292 arg10));
12296 arg11));
12298 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12301 {
12307 }
12308 }
12310 /* Attempt to simplify equality/inequality comparisons of complex
12311 values. Only lower the comparison if the result is known or
12312 can be simplified to a single scalar comparison. */
12317 {
12322 {
12325 }
12326 else
12327 {
12330 }
12333 {
12336 }
12337 else
12338 {
12341 }
12345 {
12347 {
12352 }
12353 else
12354 {
12359 }
12360 }
12364 {
12366 {
12371 }
12372 else
12373 {
12378 }
12379 }
12380 }
12392 /* Transform comparisons of the form X +- C CMP X. */
12397 {
12402 /* (X - c) > X becomes false. */
12408 /* Likewise (X + c) < X becomes false. */
12414 /* Convert (X - c) <= X to true. */
12421 /* Convert (X + c) >= X to true. */
12427 }
12429 /* If we are comparing an ABS_EXPR with a constant, we can
12430 convert all the cases into explicit comparisons, but they may
12431 well not be faster than doing the ABS and one comparison.
12432 But ABS (X) <= C is a range comparison, which becomes a subtraction
12433 and a comparison, and is probably faster. */
12447 /* Convert ABS_EXPR<x> >= 0 to true. */
12454 {
12457 "when simplifying comparison of "
12459 WARN_STRICT_OVERFLOW_CONDITIONAL);
12462 arg0);
12463 }
12465 /* Convert ABS_EXPR<x> < 0 to false. */
12470 {
12473 "when simplifying comparison of "
12475 WARN_STRICT_OVERFLOW_CONDITIONAL);
12478 arg0);
12479 }
12481 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12482 and similarly for >= into !=. */
12492 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12493 otherwise Y might be >= # of bits in X's type and thus e.g.
12494 (unsigned char) (1 << Y) for Y 15 might be 0.
12495 If the cast is widening, then 1 << Y should have unsigned type,
12496 otherwise if Y is number of bits in the signed shift type minus 1,
12497 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12498 31 might be 0xffffffff80000000. */
12511 {
12517 }
12529 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12530 {
12542 }
12547 /* When pedantic, a compound expression can be neither an lvalue
12548 nor an integer constant expression. */
12551 /* Don't let (0, 0) be null pointer constant. */
12557 /* An ASSERT_EXPR should never be passed to fold_binary. */
12563 }
12565 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12566 ((A & N) + B) & M -> (A + B) & M
12567 Similarly if (N & M) == 0,
12568 ((A | N) + B) & M -> (A + B) & M
12569 and for - instead of + (or unary - instead of +)
12570 and/or ^ instead of |.
12571 If B is constant and (B & M) == 0, fold into A & M.
12573 This function is a helper for match.pd patterns. Return non-NULL
12574 type in which the simplified operation should be performed only
12575 if any optimization is possible.
12577 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12578 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12579 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12580 +/-. */
12581 tree
12586 {
12601 wide_int cst0;
12603 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12604 arg1 (M) is == (1LL << cst) - 1.
12605 Store C into PMOP[0] and D into PMOP[1]. */
12612 {
12619 {
12622 }
12625 /* If C or D is of the form (A & N) where
12626 (N & M) == M, or of the form (A | N) or
12627 (A ^ N) where (N & M) == 0, replace it with A. */
12633 /* If C or D is a N where (N & M) == 0, it can be
12634 omitted (replaced with 0). */
12639 /* Similarly, with C - N where (-N & M) == 0. */
12647 }
12649 /* Only build anything new if we optimized one or both arguments above. */
12655 else
12657 }
12659 /* Used by contains_label_[p1]. */
12661 struct contains_label_data
12662 {
12665 };
12667 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12668 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12669 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12671 static tree
12673 {
12676 {
12687 {
12695 }
12704 }
12705 }
12707 /* Return whether the sub-tree ST contains a label which is accessible from
12708 outside the sub-tree. */
12710 static bool
12712 {
12716 }
12718 /* Fold a ternary expression of code CODE and type TYPE with operands
12719 OP0, OP1, and OP2. Return the folded expression if folding is
12720 successful. Otherwise, return NULL_TREE. */
12722 tree
12725 {
12726 tree tem;
12733 /* If this is a commutative operation, and OP0 is a constant, move it
12734 to OP1 to reduce the number of tests below. */
12743 /* Strip any conversions that don't change the mode. This is safe
12744 for every expression, except for a comparison expression because
12745 its signedness is derived from its operands. So, in the latter
12746 case, only strip conversions that don't change the signedness.
12748 Note that this is done as an internal manipulation within the
12749 constant folder, in order to find the simplest representation of
12750 the arguments so that their form can be studied. In any cases,
12751 the appropriate type conversions should be put back in the tree
12752 that will get out of the constant folder. */
12754 {
12757 }
12760 {
12763 }
12766 {
12769 }
12772 {
12776 {
12782 }
12787 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12788 so all simple results must be passed through pedantic_non_lvalue. */
12790 {
12793 /* Only optimize constant conditions when the selected branch
12794 has the same type as the COND_EXPR. This avoids optimizing
12795 away "c ? x : throw", where the throw has a void type.
12796 Avoid throwing away that operand which contains label. */
12803 }
12805 {
12812 {
12815 {
12823 }
12828 }
12829 }
12831 /* If we have A op B ? A : C, we may be able to convert this to a
12832 simpler expression, depending on the operation and the values
12833 of B and C. Signed zeros prevent all of these transformations,
12834 for reasons given above each one.
12836 Also try swapping the arguments and inverting the conditional. */
12840 {
12847 }
12852 {
12859 arg00,
12860 arg01,
12864 }
12866 /* If the second operand is simpler than the third, swap them
12867 since that produces better jump optimization results. */
12870 {
12872 /* See if this can be inverted. If it can't, possibly because
12873 it was a floating-point inequality comparison, don't do
12874 anything. */
12878 }
12880 /* Convert A ? 1 : 0 to simply A. */
12885 /* If we try to convert OP0 to our type, the
12886 call to fold will try to move the conversion inside
12887 a COND, which will recurse. In that case, the COND_EXPR
12888 is probably the best choice, so leave it alone. */
12892 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12893 over COND_EXPR in cases such as floating point comparisons. */
12902 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12907 {
12908 /* sign_bit_p looks through both zero and sign extensions,
12909 but for this optimization only sign extensions are
12910 usable. */
12913 {
12916 {
12919 }
12921 }
12922 /* sign_bit_p only checks ARG1 bits within A's precision.
12923 If <sign bit of A> has wider type than A, bits outside
12924 of A's precision in <sign bit of A> need to be checked.
12925 If they are all 0, this optimization needs to be done
12926 in unsigned A's type, if they are all 1 in signed A's type,
12927 otherwise this can't be done. */
12933 {
12935 tree tem_type;
12948 {
12951 }
12953 {
12956 }
12957 else
12959 }
12962 return
12968 arg1)));
12969 }
12971 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12972 already handled above. */
12977 {
12987 op1);
12988 }
12990 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12991 is probably obsolete because the first operand should be a
12992 truth value (that's why we have the two cases above), but let's
12993 leave it in until we can confirm this for all front-ends. */
13001 /* operand_equal_p compares just value, not precision, so e.g.
13002 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13003 second operand 32-bit -128, which is not a power of two (or vice
13004 versa. */
13008 /* Disable the transformations below for vectors, since
13009 fold_binary_op_with_conditional_arg may undo them immediately,
13010 yielding an infinite loop. */
13014 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13023 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13028 {
13030 /* Only perform transformation if ARG0 is easily inverted. */
13034 ? BIT_IOR_EXPR
13037 op1);
13038 }
13040 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13045 {
13047 /* Only perform transformation if ARG0 is easily inverted. */
13053 op2);
13054 }
13056 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13068 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13069 of fold_ternary on them. */
13079 {
13081 unsigned HOST_WIDE_INT width
13092 {
13097 {
13099 {
13104 }
13110 }
13111 }
13112 }
13114 /* On constants we can use native encode/interpret to constant
13115 fold (nearly) all BIT_FIELD_REFs. */
13121 {
13124 /* Limit us to a reasonable amount of work. To relax the
13125 other limitations we need bit-shifting of the buffer
13126 and rounding up the size. */
13130 {
13132 unsigned HOST_WIDE_INT len
13137 {
13142 }
13143 }
13144 }
13149 /* Perform constant folding of BIT_INSERT_EXPR. */
13153 {
13154 /* Build a vector of integers from the tree mask. */
13155 vec_perm_builder builder;
13159 /* Create a vec_perm_indices for the integer vector. */
13164 }
13168 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13171 {
13177 wide_int tem2
13181 }
13186 {
13188 unsigned HOST_WIDE_INT elsize
13191 {
13197 {
13203 }
13204 }
13205 }
13211 }
13213 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13214 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13215 constructor element index of the value returned. If the element is
13216 not found NULL_TREE is returned and *CTOR_IDX is updated to
13217 the index of the element after the ACCESS_INDEX position (which
13218 may be outside of the CTOR array). */
13220 tree
13223 {
13229 {
13232 {
13233 /* Static constructors for variably sized objects makes no sense. */
13236 /* ??? When it is obvious that the range is signed, treat it so. */
13241 {
13243 low_bound
13245 SIGNED);
13246 }
13247 else
13248 {
13251 }
13252 }
13253 }
13257 index_sgn);
13269 {
13270 /* Array constructor might explicitly set index, or specify a range,
13271 or leave index NULL meaning that it is next index after previous
13272 one. */
13274 {
13276 max_index = index
13278 else
13279 {
13282 index_sgn);
13283 max_index
13285 index_sgn);
13287 }
13288 }
13290 {
13296 }
13297 else
13300 /* Do we have match? */
13302 {
13304 {
13308 }
13309 }
13311 /* We're past the element we search for. Note during parsing
13312 the elements might not be sorted.
13313 ??? We should use a binary search and a flag on the
13314 CONSTRUCTOR as to whether elements are sorted in declaration
13315 order. */
13317 }
13321 }
13323 /* Perform constant folding and related simplification of EXPR.
13324 The related simplifications include x*1 => x, x*0 => 0, etc.,
13325 and application of the associative law.
13326 NOP_EXPR conversions may be removed freely (as long as we
13327 are careful not to change the type of the overall expression).
13328 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13329 but we can constant-fold them if they have constant operands. */
13331 #ifdef ENABLE_FOLD_CHECKING
13332 # define fold(x) fold_1 (x)
13334 static
13335 #endif
13336 tree
13338 {
13342 tree tem;
13345 /* Return right away if a constant. */
13349 /* CALL_EXPR-like objects with variable numbers of operands are
13350 treated specially. */
13352 {
13354 {
13357 }
13359 }
13362 {
13367 {
13385 }
13386 }
13389 {
13391 {
13398 {
13403 }
13406 }
13408 /* Return a VECTOR_CST if possible. */
13410 {
13416 tree val;
13422 }
13430 }
13432 #ifdef ENABLE_FOLD_CHECKING
13433 #undef fold
13440 /* When --enable-checking=fold, compute a digest of expr before
13441 and after actual fold call to see if fold did not accidentally
13442 change original expr. */
13444 tree
13446 {
13447 tree ret;
13467 }
13469 void
13471 {
13482 }
13484 static void
13486 {
13488 }
13490 static void
13493 {
13499 recursive_label:
13509 {
13510 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13518 }
13526 {
13527 /* Allow these fields to be modified. */
13528 tree tmp;
13539 {
13542 }
13543 }
13545 {
13546 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13547 that and change builtins.c etc. instead - see PR89543. */
13553 }
13564 {
13567 {
13583 }
13587 {
13600 }
13617 {
13623 }
13626 {
13628 {
13631 }
13633 }
13644 {
13647 }
13657 }
13658 }
13660 /* Helper function for outputting the checksum of a tree T. When
13661 debugging with gdb, you can "define mynext" to be "next" followed
13662 by "call debug_fold_checksum (op0)", then just trace down till the
13663 outputs differ. */
13665 DEBUG_FUNCTION void
13667 {
13682 }
13684 #endif
13686 /* Fold a unary tree expression with code CODE of type TYPE with an
13687 operand OP0. LOC is the location of the resulting expression.
13688 Return a folded expression if successful. Otherwise, return a tree
13689 expression with code CODE of type TYPE with an operand OP0. */
13691 tree
13694 {
13695 tree tem;
13696 #ifdef ENABLE_FOLD_CHECKING
13705 #endif
13711 #ifdef ENABLE_FOLD_CHECKING
13718 #endif
13720 }
13722 /* Fold a binary tree expression with code CODE of type TYPE with
13723 operands OP0 and OP1. LOC is the location of the resulting
13724 expression. Return a folded expression if successful. Otherwise,
13725 return a tree expression with code CODE of type TYPE with operands
13726 OP0 and OP1. */
13728 tree
13731 MEM_STAT_DECL)
13732 {
13733 tree tem;
13734 #ifdef ENABLE_FOLD_CHECKING
13751 #endif
13757 #ifdef ENABLE_FOLD_CHECKING
13772 #endif
13774 }
13776 /* Fold a ternary tree expression with code CODE of type TYPE with
13777 operands OP0, OP1, and OP2. Return a folded expression if
13778 successful. Otherwise, return a tree expression with code CODE of
13779 type TYPE with operands OP0, OP1, and OP2. */
13781 tree
13784 {
13785 tree tem;
13786 #ifdef ENABLE_FOLD_CHECKING
13810 #endif
13817 #ifdef ENABLE_FOLD_CHECKING
13840 #endif
13842 }
13844 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13845 arguments in ARGARRAY, and a null static chain.
13846 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13847 of type TYPE from the given operands as constructed by build_call_array. */
13849 tree
13852 {
13853 tree tem;
13854 #ifdef ENABLE_FOLD_CHECKING
13873 #endif
13879 #ifdef ENABLE_FOLD_CHECKING
13895 #endif
13897 }
13899 /* Perform constant folding and related simplification of initializer
13900 expression EXPR. These behave identically to "fold_buildN" but ignore
13901 potential run-time traps and exceptions that fold must preserve. */
13903 #define START_FOLD_INIT \
13904 int saved_signaling_nans = flag_signaling_nans;\
13905 int saved_trapping_math = flag_trapping_math;\
13906 int saved_rounding_math = flag_rounding_math;\
13907 int saved_trapv = flag_trapv;\
13908 int saved_folding_initializer = folding_initializer;\
13909 flag_signaling_nans = 0;\
13910 flag_trapping_math = 0;\
13911 flag_rounding_math = 0;\
13912 flag_trapv = 0;\
13913 folding_initializer = 1;
13915 #define END_FOLD_INIT \
13916 flag_signaling_nans = saved_signaling_nans;\
13917 flag_trapping_math = saved_trapping_math;\
13918 flag_rounding_math = saved_rounding_math;\
13919 flag_trapv = saved_trapv;\
13920 folding_initializer = saved_folding_initializer;
13922 tree
13925 {
13926 tree result;
13927 START_FOLD_INIT;
13931 END_FOLD_INIT;
13933 }
13935 tree
13938 {
13939 tree result;
13940 START_FOLD_INIT;
13944 END_FOLD_INIT;
13946 }
13948 tree
13951 {
13952 tree result;
13953 START_FOLD_INIT;
13957 END_FOLD_INIT;
13959 }
13961 #undef START_FOLD_INIT
13962 #undef END_FOLD_INIT
13964 /* Determine if first argument is a multiple of second argument. Return 0 if
13965 it is not, or we cannot easily determined it to be.
13967 An example of the sort of thing we care about (at this point; this routine
13968 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13969 fold cases do now) is discovering that
13971 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13973 is a multiple of
13975 SAVE_EXPR (J * 8)
13977 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13979 This code also handles discovering that
13981 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13983 is a multiple of 8 so we don't have to worry about dealing with a
13984 possible remainder.
13986 Note that we *look* inside a SAVE_EXPR only to determine how it was
13987 calculated; it is not safe for fold to do much of anything else with the
13988 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13989 at run time. For example, the latter example above *cannot* be implemented
13990 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13991 evaluation time of the original SAVE_EXPR is not necessarily the same at
13992 the time the new expression is evaluated. The only optimization of this
13993 sort that would be valid is changing
13995 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13997 divided by 8 to
13999 SAVE_EXPR (I) * SAVE_EXPR (J)
14001 (where the same SAVE_EXPR (J) is used in the original and the
14002 transformed version). */
14004 int
14006 {
14017 {
14019 /* Bitwise and provides a power of two multiple. If the mask is
14020 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14028 {
14034 {
14037 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14039 {
14043 {
14046 }
14047 }
14049 }
14050 }
14055 /* It is impossible to prove if op0 - op1 is multiple of bottom
14056 precisely, so be conservative here checking if both op0 and op1
14057 are multiple of bottom. Note we check the second operand first
14058 since it's usually simpler. */
14063 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
14064 as op0 - 3 if the expression has unsigned type. For example,
14065 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
14075 {
14077 /* const_binop may not detect overflow correctly,
14078 so check for it explicitly here. */
14086 }
14090 /* Can't handle conversions from non-integral or wider integral type. */
14096 /* fall through */
14113 SIGNED);
14119 {
14122 /* Check for special cases to see if top is defined as multiple
14123 of bottom:
14125 top = (X & ~(bottom - 1) ; bottom is power of 2
14127 or
14129 Y = X % bottom
14130 top = X - Y. */
14149 }
14151 /* fall through */
14159 }
14160 }
14162 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14163 This function returns true for integer expressions, and returns
14164 false if uncertain. */
14166 bool
14168 {
14173 {
14196 {
14197 CASE_CFN_FABS:
14199 CASE_CFN_FMAX:
14200 CASE_CFN_FMIN:
14205 }
14209 }
14210 }
14212 /* Return true if expression X evaluates to an infinity.
14213 This function returns false for integer expressions. */
14215 bool
14217 {
14221 {
14234 }
14235 }
14237 /* Return true if expression X could evaluate to an infinity.
14238 This function returns false for integer expressions, and returns
14239 true if uncertain. */
14241 bool
14243 {
14247 {
14260 }
14261 }
14263 /* Return true if expression X evaluates to a signaling NaN.
14264 This function returns false for integer expressions. */
14266 bool
14268 {
14272 {
14283 }
14284 }
14286 /* Return true if expression X could evaluate to a signaling NaN.
14287 This function returns false for integer expressions, and returns
14288 true if uncertain. */
14290 bool
14292 {
14296 {
14316 {
14317 CASE_CFN_FABS:
14319 CASE_CFN_FMAX:
14320 CASE_CFN_FMIN:
14325 }
14328 }
14329 }
14331 /* Return true if expression X evaluates to a NaN.
14332 This function returns false for integer expressions. */
14334 bool
14336 {
14340 {
14351 }
14352 }
14354 /* Return true if expression X could evaluate to a NaN.
14355 This function returns false for integer expressions, and returns
14356 true if uncertain. */
14358 bool
14360 {
14364 {
14389 {
14390 CASE_CFN_FABS:
14392 CASE_CFN_FMAX:
14393 CASE_CFN_FMIN:
14398 }
14401 }
14402 }
14404 /* Return true if expression X could evaluate to -0.0.
14405 This function returns true if uncertain. */
14407 bool
14409 {
14413 {
14428 {
14429 CASE_CFN_FABS:
14433 }
14436 }
14437 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14438 * but currently those predicates require tree and not const_tree. */
14440 }
14442 #define tree_expr_nonnegative_warnv_p(X, Y) \
14445 #define RECURSE(X) \
14446 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14448 /* Return true if CODE or TYPE is known to be non-negative. */
14450 static bool
14452 {
14455 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14456 have a signed:1 type (where the value is -1 and 0). */
14459 }
14461 /* Return true if (CODE OP0) is known to be non-negative. If the return
14462 value is based on the assumption that signed overflow is undefined,
14463 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14464 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14466 bool
14469 {
14474 {
14476 /* We can't return 1 if flag_wrapv is set because
14477 ABS_EXPR<INT_MIN> = INT_MIN. */
14481 {
14484 }
14492 CASE_CONVERT:
14493 {
14498 {
14502 {
14506 }
14507 }
14509 {
14515 }
14516 }
14521 }
14523 /* We don't know sign of `t', so be conservative and return false. */
14525 }
14527 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14528 value is based on the assumption that signed overflow is undefined,
14529 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14530 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14532 bool
14536 {
14541 {
14547 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14548 both unsigned and at least 2 bits shorter than the result. */
14552 {
14557 {
14561 }
14562 }
14567 {
14568 /* x * x is always non-negative for floating point x
14569 or without overflow. */
14572 {
14577 }
14578 }
14580 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14581 both unsigned and their total bits is shorter than the result. */
14585 {
14604 {
14614 }
14615 }
14622 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14623 things. */
14648 }
14650 /* We don't know sign of `t', so be conservative and return false. */
14652 }
14654 /* Return true if T is known to be non-negative. If the return
14655 value is based on the assumption that signed overflow is undefined,
14656 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14657 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14659 bool
14661 {
14666 {
14680 /* Limit the depth of recursion to avoid quadratic behavior.
14681 This is expected to catch almost all occurrences in practice.
14682 If this code misses important cases that unbounded recursion
14683 would not, passes that need this information could be revised
14684 to provide it through dataflow propagation. */
14692 }
14693 }
14695 /* Return true if T is known to be non-negative. If the return
14696 value is based on the assumption that signed overflow is undefined,
14697 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14698 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14700 bool
14703 {
14705 {
14706 CASE_CFN_ACOS:
14707 CASE_CFN_ACOSH:
14708 CASE_CFN_CABS:
14709 CASE_CFN_COSH:
14710 CASE_CFN_ERFC:
14711 CASE_CFN_EXP:
14712 CASE_CFN_EXP10:
14713 CASE_CFN_EXP2:
14714 CASE_CFN_FABS:
14715 CASE_CFN_FDIM:
14716 CASE_CFN_HYPOT:
14717 CASE_CFN_POW10:
14718 CASE_CFN_FFS:
14719 CASE_CFN_PARITY:
14720 CASE_CFN_POPCOUNT:
14721 CASE_CFN_CLZ:
14722 CASE_CFN_CLRSB:
14727 /* Always true. */
14730 CASE_CFN_SQRT:
14731 CASE_CFN_SQRT_FN:
14732 /* sqrt(-0.0) is -0.0. */
14737 CASE_CFN_ASINH:
14738 CASE_CFN_ATAN:
14739 CASE_CFN_ATANH:
14740 CASE_CFN_CBRT:
14741 CASE_CFN_CEIL:
14742 CASE_CFN_CEIL_FN:
14743 CASE_CFN_ERF:
14744 CASE_CFN_EXPM1:
14745 CASE_CFN_FLOOR:
14746 CASE_CFN_FLOOR_FN:
14747 CASE_CFN_FMOD:
14748 CASE_CFN_FREXP:
14749 CASE_CFN_ICEIL:
14750 CASE_CFN_IFLOOR:
14751 CASE_CFN_IRINT:
14752 CASE_CFN_IROUND:
14753 CASE_CFN_LCEIL:
14754 CASE_CFN_LDEXP:
14755 CASE_CFN_LFLOOR:
14756 CASE_CFN_LLCEIL:
14757 CASE_CFN_LLFLOOR:
14758 CASE_CFN_LLRINT:
14759 CASE_CFN_LLROUND:
14760 CASE_CFN_LRINT:
14761 CASE_CFN_LROUND:
14762 CASE_CFN_MODF:
14763 CASE_CFN_NEARBYINT:
14764 CASE_CFN_NEARBYINT_FN:
14765 CASE_CFN_RINT:
14766 CASE_CFN_RINT_FN:
14767 CASE_CFN_ROUND:
14768 CASE_CFN_ROUND_FN:
14769 CASE_CFN_ROUNDEVEN:
14770 CASE_CFN_ROUNDEVEN_FN:
14771 CASE_CFN_SCALB:
14772 CASE_CFN_SCALBLN:
14773 CASE_CFN_SCALBN:
14774 CASE_CFN_SIGNBIT:
14775 CASE_CFN_SIGNIFICAND:
14776 CASE_CFN_SINH:
14777 CASE_CFN_TANH:
14778 CASE_CFN_TRUNC:
14779 CASE_CFN_TRUNC_FN:
14780 /* True if the 1st argument is nonnegative. */
14783 CASE_CFN_FMAX:
14784 CASE_CFN_FMAX_FN:
14785 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14786 things. In the presence of sNaNs, we're only guaranteed to be
14787 non-negative if both operands are non-negative. In the presence
14788 of qNaNs, we're non-negative if either operand is non-negative
14789 and can't be a qNaN, or if both operands are non-negative. */
14798 CASE_CFN_FMIN:
14799 CASE_CFN_FMIN_FN:
14800 /* True if the 1st AND 2nd arguments are nonnegative. */
14803 CASE_CFN_COPYSIGN:
14804 CASE_CFN_COPYSIGN_FN:
14805 /* True if the 2nd argument is nonnegative. */
14808 CASE_CFN_POWI:
14809 /* True if the 1st argument is nonnegative or the second
14810 argument is an even integer. */
14816 CASE_CFN_POW:
14817 /* True if the 1st argument is nonnegative or the second
14818 argument is an even integer valued real. */
14820 {
14821 REAL_VALUE_TYPE c;
14822 HOST_WIDE_INT n;
14827 {
14828 REAL_VALUE_TYPE cint;
14832 }
14833 }
14838 }
14840 }
14842 /* Return true if T is known to be non-negative. If the return
14843 value is based on the assumption that signed overflow is undefined,
14844 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14845 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14847 static bool
14849 {
14855 {
14857 {
14861 /* If the initializer is non-void, then it's a normal expression
14862 that will be assigned to the slot. */
14866 /* Otherwise, the initializer sets the slot in some way. One common
14867 way is an assignment statement at the end of the initializer. */
14869 {
14877 else
14879 }
14885 }
14888 {
14894 arg0,
14895 arg1,
14897 }
14910 }
14911 }
14913 #undef RECURSE
14914 #undef tree_expr_nonnegative_warnv_p
14916 /* Return true if T is known to be non-negative. If the return
14917 value is based on the assumption that signed overflow is undefined,
14918 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14919 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14921 bool
14923 {
14930 {
14952 }
14955 {
14981 }
14982 }
14984 /* Return true if `t' is known to be non-negative. Handle warnings
14985 about undefined signed overflow. */
14987 bool
14989 {
14996 "determining that expression is always "
14998 WARN_STRICT_OVERFLOW_MISC);
15000 }
15003 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15004 For floating point we further ensure that T is not denormal.
15005 Similar logic is present in nonzero_address in rtlanal.h.
15007 If the return value is based on the assumption that signed overflow
15008 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15009 change *STRICT_OVERFLOW_P. */
15011 bool
15014 {
15016 {
15019 strict_overflow_p);
15022 {
15028 strict_overflow_p));
15029 }
15034 strict_overflow_p);
15038 }
15041 }
15043 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15044 For floating point we further ensure that T is not denormal.
15045 Similar logic is present in nonzero_address in rtlanal.h.
15047 If the return value is based on the assumption that signed overflow
15048 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15049 change *STRICT_OVERFLOW_P. */
15051 bool
15053 tree type,
15054 tree op0,
15056 {
15059 {
15063 {
15064 /* With the presence of negative values it is hard
15065 to say something. */
15072 /* One of operands must be positive and the other non-negative. */
15073 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15074 overflows, on a twos-complement machine the sum of two
15075 nonnegative numbers can never be zero. */
15077 strict_overflow_p)
15079 strict_overflow_p));
15080 }
15085 {
15087 strict_overflow_p)
15089 strict_overflow_p))
15090 {
15093 }
15094 }
15103 {
15106 }
15113 {
15117 /* When both operands are nonzero, then MAX must be too. */
15119 strict_overflow_p))
15122 /* MAX where operand 0 is positive is positive. */
15124 strict_overflow_p);
15125 }
15126 /* MAX where operand 1 is positive is positive. */
15131 {
15135 }
15140 strict_overflow_p)
15142 strict_overflow_p));
15146 }
15149 }
15151 /* Return true when T is an address and is known to be nonzero.
15152 For floating point we further ensure that T is not denormal.
15153 Similar logic is present in nonzero_address in rtlanal.h.
15155 If the return value is based on the assumption that signed overflow
15156 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15157 change *STRICT_OVERFLOW_P. */
15159 bool
15161 {
15164 {
15169 {
15181 /* For objects in symbol table check if we know they are non-zero.
15182 Don't do anything for variables and functions before symtab is built;
15183 it is quite possible that they will be declared weak later. */
15188 /* Constants are never weak. */
15193 }
15201 {
15205 }
15215 }
15217 }
15219 #define integer_valued_real_p(X) \
15222 #define RECURSE(X) \
15223 ((integer_valued_real_p) (X, depth + 1))
15225 /* Return true if the floating point result of (CODE OP0) has an
15226 integer value. We also allow +Inf, -Inf and NaN to be considered
15227 integer values. Return false for signaling NaN.
15229 DEPTH is the current nesting depth of the query. */
15231 bool
15233 {
15235 {
15242 CASE_CONVERT:
15243 {
15250 }
15254 }
15256 }
15258 /* Return true if the floating point result of (CODE OP0 OP1) has an
15259 integer value. We also allow +Inf, -Inf and NaN to be considered
15260 integer values. Return false for signaling NaN.
15262 DEPTH is the current nesting depth of the query. */
15264 bool
15266 {
15268 {
15278 }
15280 }
15282 /* Return true if the floating point result of calling FNDECL with arguments
15283 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15284 considered integer values. Return false for signaling NaN. If FNDECL
15285 takes fewer than 2 arguments, the remaining ARGn are null.
15287 DEPTH is the current nesting depth of the query. */
15289 bool
15291 {
15293 {
15294 CASE_CFN_CEIL:
15295 CASE_CFN_CEIL_FN:
15296 CASE_CFN_FLOOR:
15297 CASE_CFN_FLOOR_FN:
15298 CASE_CFN_NEARBYINT:
15299 CASE_CFN_NEARBYINT_FN:
15300 CASE_CFN_RINT:
15301 CASE_CFN_RINT_FN:
15302 CASE_CFN_ROUND:
15303 CASE_CFN_ROUND_FN:
15304 CASE_CFN_ROUNDEVEN:
15305 CASE_CFN_ROUNDEVEN_FN:
15306 CASE_CFN_TRUNC:
15307 CASE_CFN_TRUNC_FN:
15310 CASE_CFN_FMIN:
15311 CASE_CFN_FMIN_FN:
15312 CASE_CFN_FMAX:
15313 CASE_CFN_FMAX_FN:
15318 }
15320 }
15322 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15323 has an integer value. We also allow +Inf, -Inf and NaN to be
15324 considered integer values. Return false for signaling NaN.
15326 DEPTH is the current nesting depth of the query. */
15328 bool
15330 {
15332 {
15340 /* Limit the depth of recursion to avoid quadratic behavior.
15341 This is expected to catch almost all occurrences in practice.
15342 If this code misses important cases that unbounded recursion
15343 would not, passes that need this information could be revised
15344 to provide it through dataflow propagation. */
15348 depth));
15352 }
15354 }
15356 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15357 has an integer value. We also allow +Inf, -Inf and NaN to be
15358 considered integer values. Return false for signaling NaN.
15360 DEPTH is the current nesting depth of the query. */
15362 static bool
15364 {
15366 {
15377 }
15379 }
15381 #undef RECURSE
15382 #undef integer_valued_real_p
15384 /* Return true if the floating point expression T has an integer value.
15385 We also allow +Inf, -Inf and NaN to be considered integer values.
15386 Return false for signaling NaN.
15388 DEPTH is the current nesting depth of the query. */
15390 bool
15392 {
15400 {
15416 }
15419 {
15425 {
15434 }
15438 }
15439 }
15441 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15442 attempt to fold the expression to a constant without modifying TYPE,
15443 OP0 or OP1.
15445 If the expression could be simplified to a constant, then return
15446 the constant. If the expression would not be simplified to a
15447 constant, then return NULL_TREE. */
15449 tree
15451 {
15454 }
15456 /* Given the components of a unary expression CODE, TYPE and OP0,
15457 attempt to fold the expression to a constant without modifying
15458 TYPE or OP0.
15460 If the expression could be simplified to a constant, then return
15461 the constant. If the expression would not be simplified to a
15462 constant, then return NULL_TREE. */
15464 tree
15466 {
15469 }
15471 /* If EXP represents referencing an element in a constant string
15472 (either via pointer arithmetic or array indexing), return the
15473 tree representing the value accessed, otherwise return NULL. */
15475 tree
15477 {
15481 {
15483 tree index;
15484 tree string;
15489 else
15490 {
15494 /* Optimize the special-case of a zero lower bound.
15496 We convert the low_bound to sizetype to avoid some problems
15497 with constant folding. (E.g. suppose the lower bound is 1,
15498 and its mode is QI. Without the conversion,l (ARRAY
15499 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15500 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15506 }
15508 scalar_int_mode char_mode;
15520 }
15522 }
15524 /* Folds a read from vector element at IDX of vector ARG. */
15526 tree
15528 {
15533 {
15537 {
15544 }
15545 }
15547 }
15549 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15550 an integer constant, real, or fixed-point constant.
15552 TYPE is the type of the result. */
15554 static tree
15556 {
15560 {
15566 {
15567 FIXED_VALUE_TYPE f;
15572 /* Propagate overflow flags. */
15576 }
15580 {
15587 }
15590 }
15593 }
15595 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15596 an integer constant or real constant.
15598 TYPE is the type of the result. */
15600 tree
15602 {
15606 {
15608 {
15609 /* If the value is unsigned or non-negative, then the absolute value
15610 is the same as the ordinary value. */
15614 ;
15616 /* If the value is negative, then the absolute value is
15617 its negation. */
15618 else
15621 /* Force to the destination type, set TREE_OVERFLOW for signed
15622 TYPE only. */
15624 }
15630 else
15636 }
15639 }
15641 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15642 constant. TYPE is the type of the result. */
15644 static tree
15646 {
15650 }
15652 /* Given CODE, a relational operator, the target type, TYPE and two
15653 constant operands OP0 and OP1, return the result of the
15654 relational operation. If the result is not a compile time
15655 constant, then return NULL_TREE. */
15657 static tree
15659 {
15662 /* From here on, the only cases we handle are when the result is
15663 known to be a constant. */
15666 {
15670 /* Handle the cases where either operand is a NaN. */
15672 {
15674 {
15702 }
15705 }
15708 }
15711 {
15715 }
15717 /* Handle equality/inequality of complex constants. */
15719 {
15730 else
15732 }
15735 {
15737 {
15738 /* Have vector comparison with scalar boolean result. */
15746 {
15754 }
15756 }
15757 tree_vector_builder elts;
15762 {
15775 }
15778 }
15780 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15782 To compute GT, swap the arguments and do LT.
15783 To compute GE, do LT and invert the result.
15784 To compute LE, swap the arguments, do LT and invert the result.
15785 To compute NE, do EQ and invert the result.
15787 Therefore, the code below must handle only EQ and LT. */
15790 {
15793 }
15795 /* Note that it is safe to invert for real values here because we
15796 have already handled the one case that it matters. */
15800 {
15803 }
15805 /* Compute a result for LT or EQ if args permit;
15806 Otherwise return T. */
15808 {
15811 else
15813 }
15814 else
15820 }
15822 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15823 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15824 itself. */
15826 tree
15828 {
15829 /* If the expression does not have side effects then we don't have to wrap
15830 it with a cleanup point expression. */
15834 /* If the expression is a return, check to see if the expression inside the
15835 return has no side effects or the right hand side of the modify expression
15836 inside the return. If either don't have side effects set we don't need to
15837 wrap the expression in a cleanup point expression. Note we don't check the
15838 left hand side of the modify because it should always be a return decl. */
15840 {
15847 }
15850 }
15852 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15853 of an indirection through OP0, or NULL_TREE if no simplification is
15854 possible. */
15856 tree
15858 {
15860 tree subtype;
15861 poly_uint64 const_op01;
15870 {
15874 /* *&CONST_DECL -> to the value of the const decl. */
15877 /* *&p => p; make sure to handle *&"str"[cst] here. */
15879 {
15883 else
15885 }
15886 /* *(foo *)&fooarray => fooarray[0] */
15889 && (!in_gimple_form
15891 {
15901 }
15902 /* *(foo *)&complexfoo => __real__ complexfoo */
15906 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15909 {
15913 index);
15914 }
15915 }
15919 {
15925 {
15926 tree op00type;
15930 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15933 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
15934 but we want to treat offsets with MSB set as negative.
15935 For the code below negative offsets are invalid and
15936 TYPE_SIZE of the element is something unsigned, so
15937 check whether op01 fits into poly_int64, which implies
15938 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
15939 then just use poly_uint64 because we want to treat the
15940 value as unsigned. */
15942 {
15944 poly_uint64 max_offset
15948 {
15953 }
15954 }
15955 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15958 {
15960 const_op01))
15962 }
15963 /* ((foo *)&fooarray)[1] => fooarray[1] */
15966 {
15975 {
15980 }
15981 }
15982 }
15983 }
15985 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15988 && (!in_gimple_form
15990 {
15991 tree type_domain;
16001 NULL_TREE);
16002 }
16005 }
16007 /* Builds an expression for an indirection through T, simplifying some
16008 cases. */
16010 tree
16012 {
16020 }
16022 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16024 tree
16026 {
16031 else
16033 }
16035 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16036 whose result is ignored. The type of the returned tree need not be
16037 the same as the original expression. */
16039 tree
16041 {
16047 {
16058 else
16064 {
16080 }
16085 }
16086 }
16088 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16090 tree
16092 {
16098 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16099 have to do anything. Only do this when we are not given a const,
16100 because in that case, this check is more expensive than just
16101 doing it. */
16103 {
16108 }
16110 /* If divisor is a power of two, simplify this to bit manipulation. */
16112 {
16114 {
16128 }
16129 else
16130 {
16131 tree t;
16137 }
16138 }
16139 else
16140 {
16145 }
16148 }
16150 /* Likewise, but round down. */
16152 tree
16154 {
16161 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16162 have to do anything. Only do this when we are not given a const,
16163 because in that case, this check is more expensive than just
16164 doing it. */
16166 {
16171 }
16173 /* If divisor is a power of two, simplify this to bit manipulation. */
16175 {
16176 tree t;
16180 }
16181 else
16182 {
16187 }
16190 }
16192 /* Returns the pointer to the base of the object addressed by EXP and
16193 extracts the information about the offset of the access, storing it
16194 to PBITPOS and POFFSET. */
16196 static tree
16199 {
16200 tree core;
16201 machine_mode mode;
16203 poly_int64 bitsize;
16207 {
16212 }
16214 {
16220 {
16221 poly_offset_int tem
16227 }
16228 }
16229 else
16230 {
16234 }
16237 }
16239 /* Returns true if addresses of E1 and E2 differ by a constant, false
16240 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16242 bool
16244 {
16259 {
16269 }
16271 {
16272 /* If only one of the offsets is non-constant, the difference cannot
16273 be a constant. */
16275 }
16276 else
16281 }
16283 /* Return OFF converted to a pointer offset type suitable as offset for
16284 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16285 tree
16287 {
16291 }
16293 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16294 tree
16296 {
16299 }
16301 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16302 tree
16304 {
16307 }
16309 /* Return a pointer to a NUL-terminated string containing the sequence
16310 of bytes corresponding to the representation of the object referred to
16311 by SRC (or a subsequence of such bytes within it if SRC is a reference
16312 to an initialized constant array plus some constant offset).
16313 Set *STRSIZE the number of bytes in the constant sequence including
16314 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16315 where A is the array that stores the constant sequence that SRC points
16316 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16317 need not point to a string or even an array of characters but may point
16318 to an object of any type. */
16322 {
16323 /* The offset into the array A storing the string, and A's byte size. */
16324 tree offset_node;
16325 tree mem_size;
16332 else
16339 {
16342 else
16344 }
16349 /* ARRAY_SIZE is the byte size of the array the constant sequence
16350 is stored in and equal to sizeof A. INIT_BYTES is the number
16351 of bytes in the constant sequence used to initialize the array,
16352 including any embedded NULs as well as the terminating NUL (for
16353 strings), but not including any trailing zeros/NULs past
16354 the terminating one appended implicitly to a string literal to
16355 zero out the remainder of the array it's stored in. For example,
16356 given:
16357 const char a[7] = "abc\0d";
16358 n = strlen (a + 1);
16359 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16360 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16361 is equal to strlen (A) + 1. */
16366 /* Ideally this would turn into a gcc_checking_assert over time. */
16374 {
16375 /* Compute and store the number of characters from the beginning
16376 of the substring at OFFSET to the end, including the terminating
16377 nul. Offsets past the initial length refer to null strings. */
16380 else
16382 }
16383 else
16384 {
16386 /* Support only properly NUL-terminated single byte strings. */
16391 }
16394 }
16396 /* Return a pointer to a NUL-terminated string corresponding to
16397 the expression STR referencing a constant string, possibly
16398 involving a constant offset. Return null if STR either doesn't
16399 reference a constant string or if it involves a nonconstant
16400 offset. */
16404 {
16406 }
16408 /* Given a tree T, compute which bits in T may be nonzero. */
16410 wide_int
16412 {
16414 {
16432 CASE_CONVERT:
16438 {
16443 }
16447 {
16455 }
16459 {
16467 }
16471 }
16474 }
16476 #if CHECKING_P
16480 /* Helper functions for writing tests of folding trees. */
16482 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16484 static void
16486 tree constant)
16487 {
16489 }
16491 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16492 wrapping WRAPPED_EXPR. */
16494 static void
16496 tree wrapped_expr)
16497 {
16502 }
16504 /* Verify that various arithmetic binary operations are folded
16505 correctly. */
16507 static void
16509 {
16515 /* Addition. */
16516 /* 1 <-- (0 + 1) */
16518 one);
16520 one);
16522 /* (nonlvalue)x <-- (x + 0) */
16524 x);
16526 /* Subtraction. */
16527 /* 0 <-- (x - x) */
16529 zero);
16531 x);
16533 /* Multiplication. */
16534 /* 0 <-- (x * 0) */
16536 zero);
16538 /* (nonlvalue)x <-- (x * 1) */
16540 x);
16541 }
16543 /* Verify that various binary operations on vectors are folded
16544 correctly. */
16546 static void
16548 {
16555 /* Verify equality tests that return a scalar boolean result. */
16568 }
16570 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16572 static void
16574 {
16577 /* This will be 1 if VEC_MODE isn't a vector mode. */
16584 }
16586 /* Run all of the selftests within this file. */
16588 void
16590 {
16594 }