| blob | e77d74e40b06a68076a53dc2b9840ac0c640d69d |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2020 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /*@@ This file should be rewritten to use an arbitrary precision
21 @@ representation for "struct tree_int_cst" and "struct tree_real_cst".
22 @@ Perhaps the routines could also be used for bc/dc, and made a lib.
23 @@ The routines that translate from the ap rep should
24 @@ warn if precision et. al. is lost.
25 @@ This would also make life easier when this technology is used
26 @@ for cross-compilers. */
28 /* The entry points in this file are fold, size_int_wide and size_binop.
30 fold takes a tree as argument and returns a simplified tree.
32 size_binop takes a tree code for an arithmetic operation
33 and two operands that are trees, and produces a tree for the
34 result, assuming the type comes from `sizetype'.
36 size_int takes an integer value, and creates a tree constant
37 with type from `sizetype'.
39 Note: Since the folders get called on non-gimple code as well as
40 gimple code, we need to handle GIMPLE tuples as well as their
41 corresponding tree equivalents. */
86 /* Nonzero if we are folding constants inside an initializer; zero
87 otherwise. */
90 /* The following constants represent a bit based encoding of GCC's
91 comparison operators. This encoding simplifies transformations
92 on relational comparison operators, such as AND and OR. */
110 };
143 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
144 Otherwise, return LOC. */
146 static location_t
148 {
151 }
153 /* Similar to protected_set_expr_location, but never modify x in place,
154 if location can and needs to be set, unshare it. */
158 {
164 {
167 }
169 }
170 \f
171 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
172 division and returns the quotient. Otherwise returns
173 NULL_TREE. */
175 tree
177 {
178 widest_int quo;
185 }
186 \f
187 /* This is nonzero if we should defer warnings about undefined
188 overflow. This facility exists because these warnings are a
189 special case. The code to estimate loop iterations does not want
190 to issue any warnings, since it works with expressions which do not
191 occur in user code. Various bits of cleanup code call fold(), but
192 only use the result if it has certain characteristics (e.g., is a
193 constant); that code only wants to issue a warning if the result is
194 used. */
198 /* If a warning about undefined overflow is deferred, this is the
199 warning. Note that this may cause us to turn two warnings into
200 one, but that is fine since it is sufficient to only give one
201 warning per expression. */
205 /* If a warning about undefined overflow is deferred, this is the
206 level at which the warning should be emitted. */
210 /* Start deferring overflow warnings. We could use a stack here to
211 permit nested calls, but at present it is not necessary. */
213 void
215 {
217 }
219 /* Stop deferring overflow warnings. If there is a pending warning,
220 and ISSUE is true, then issue the warning if appropriate. STMT is
221 the statement with which the warning should be associated (used for
222 location information); STMT may be NULL. CODE is the level of the
223 warning--a warn_strict_overflow_code value. This function will use
224 the smaller of CODE and the deferred code when deciding whether to
225 issue the warning. CODE may be zero to mean to always use the
226 deferred code. */
228 void
230 {
232 location_t locus;
237 {
243 }
254 /* Use the smallest code level when deciding to issue the
255 warning. */
264 else
267 }
269 /* Stop deferring overflow warnings, ignoring any deferred
270 warnings. */
272 void
274 {
276 }
278 /* Whether we are deferring overflow warnings. */
280 bool
282 {
284 }
286 /* This is called when we fold something based on the fact that signed
287 overflow is undefined. */
289 void
291 {
293 {
296 {
299 }
300 }
303 }
304 \f
305 /* Return true if the built-in mathematical function specified by CODE
306 is odd, i.e. -f(x) == f(-x). */
308 bool
310 {
312 {
313 CASE_CFN_ASIN:
314 CASE_CFN_ASINH:
315 CASE_CFN_ATAN:
316 CASE_CFN_ATANH:
317 CASE_CFN_CASIN:
318 CASE_CFN_CASINH:
319 CASE_CFN_CATAN:
320 CASE_CFN_CATANH:
321 CASE_CFN_CBRT:
322 CASE_CFN_CPROJ:
323 CASE_CFN_CSIN:
324 CASE_CFN_CSINH:
325 CASE_CFN_CTAN:
326 CASE_CFN_CTANH:
327 CASE_CFN_ERF:
328 CASE_CFN_LLROUND:
329 CASE_CFN_LROUND:
330 CASE_CFN_ROUND:
331 CASE_CFN_ROUNDEVEN:
332 CASE_CFN_ROUNDEVEN_FN:
333 CASE_CFN_SIN:
334 CASE_CFN_SINH:
335 CASE_CFN_TAN:
336 CASE_CFN_TANH:
337 CASE_CFN_TRUNC:
340 CASE_CFN_LLRINT:
341 CASE_CFN_LRINT:
342 CASE_CFN_NEARBYINT:
343 CASE_CFN_RINT:
348 }
350 }
352 /* Check whether we may negate an integer constant T without causing
353 overflow. */
355 bool
357 {
358 tree type;
367 }
369 /* Determine whether an expression T can be cheaply negated using
370 the function negate_expr without introducing undefined overflow. */
372 static bool
374 {
375 tree type;
384 {
389 /* Check that -CST will not overflow type. */
402 /* We want to canonicalize to positive real constants. Pretend
403 that only negative ones can be easily negated. */
411 {
415 /* Steps don't prevent negation. */
422 }
437 /* -(A + B) -> (-B) - A. */
440 /* -(A + B) -> (-A) - B. */
444 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
453 /* INT_MIN/n * n doesn't overflow while negating one operand it does
454 if n is a (negative) power of two. */
465 /* Fall through. */
478 /* In general we can't negate A in A / B, because if A is INT_MIN and
479 B is not 1 we change the sign of the result. */
483 /* In general we can't negate B in A / B, because if A is INT_MIN and
484 B is 1, we may turn this into INT_MIN / -1 which is undefined
485 and actually traps on some architectures. */
494 /* Negate -((double)float) as (double)(-float). */
496 {
500 }
504 /* Negate -f(x) as f(-x). */
510 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
512 {
516 }
521 }
523 }
525 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
526 simplification is possible.
527 If negate_expr_p would return true for T, NULL_TREE will never be
528 returned. */
530 static tree
532 {
534 tree tem;
537 {
538 /* Convert - (~A) to A + 1. */
562 {
567 }
571 {
572 tree_vector_builder elts;
576 {
581 }
584 }
607 {
608 /* -(A + B) -> (-B) - A. */
610 {
614 }
616 /* -(A + B) -> (-A) - B. */
618 {
622 }
623 }
627 /* - (A - B) -> B - A */
638 /* Fall through. */
642 {
651 }
659 /* In general we can't negate A in A / B, because if A is INT_MIN and
660 B is not 1 we change the sign of the result. */
666 /* In general we can't negate B in A / B, because if A is INT_MIN and
667 B is 1, we may turn this into INT_MIN / -1 which is undefined
668 and actually traps on some architectures. */
680 /* Convert -((double)float) into (double)(-float). */
682 {
686 }
690 /* Negate -f(x) as f(-x). */
693 {
699 }
703 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
705 {
708 {
715 }
716 }
721 }
724 }
726 /* A wrapper for fold_negate_expr_1. */
728 static tree
730 {
737 }
739 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
740 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
741 return NULL_TREE. */
743 static tree
745 {
747 location_t loc;
760 }
761 \f
762 /* Split a tree IN into a constant, literal and variable parts that could be
763 combined with CODE to make IN. "constant" means an expression with
764 TREE_CONSTANT but that isn't an actual constant. CODE must be a
765 commutative arithmetic operation. Store the constant part into *CONP,
766 the literal in *LITP and return the variable part. If a part isn't
767 present, set it to null. If the tree does not decompose in this way,
768 return the entire tree as the variable part and the other parts as null.
770 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
771 case, we negate an operand that was subtracted. Except if it is a
772 literal for which we use *MINUS_LITP instead.
774 If NEGATE_P is true, we are negating all of IN, again except a literal
775 for which we use *MINUS_LITP instead. If a variable part is of pointer
776 type, it is negated after converting to TYPE. This prevents us from
777 generating illegal MINUS pointer expression. LOC is the location of
778 the converted variable part.
780 If IN is itself a literal or constant, return it as appropriate.
782 Note that we do not guarantee that any of the three values will be the
783 same type as IN, but they will have the same signedness and mode. */
785 static tree
789 {
797 /* Strip any conversions that don't change the machine mode or signedness. */
806 /* We can associate addition and subtraction together (even
807 though the C standard doesn't say so) for integers because
808 the value is not affected. For reals, the value might be
809 affected, so we can't. */
815 {
821 /* First see if either of the operands is a literal, then a constant. */
834 /* If we haven't dealt with either operand, this is not a case we can
835 decompose. Otherwise, VAR is either of the ones remaining, if any. */
840 else
843 /* Now do any needed negations. */
850 }
855 {
856 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
857 when IN is constant. */
860 }
861 else
865 {
878 }
888 }
890 /* Re-associate trees split by the above function. T1 and T2 are
891 either expressions to associate or null. Return the new
892 expression, if any. LOC is the location of the new expression. If
893 we build an operation, do it in TYPE and with CODE. */
895 static tree
897 {
899 {
902 }
906 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
907 try to fold this since we will have infinite recursion. But do
908 deal with any NEGATE_EXPRs. */
912 {
914 {
927 }
929 {
932 }
936 }
940 }
941 \f
942 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
943 for use in int_const_binop, size_binop and size_diffop. */
945 static bool
947 {
954 {
963 }
968 }
970 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
971 a new constant in RES. Return FALSE if we don't know how to
972 evaluate CODE at compile-time. */
974 bool
978 {
979 wide_int tmp;
982 {
1004 /* It's unclear from the C standard whether shifts can overflow.
1005 The following code ignores overflow; perhaps a C standard
1006 interpretation ruling is needed. */
1013 {
1017 else
1019 }
1020 else
1025 else
1104 }
1106 }
1108 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1109 produce a new constant in RES. Return FALSE if we don't know how
1110 to evaluate CODE at compile-time. */
1112 static bool
1116 {
1120 {
1138 else
1145 else
1158 }
1160 }
1162 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1163 produce a new constant. Return NULL_TREE if we don't know how to
1164 evaluate CODE at compile-time. */
1166 tree
1169 {
1170 poly_wide_int poly_res;
1176 {
1182 }
1191 }
1193 /* Return true if binary operation OP distributes over addition in operand
1194 OPNO, with the other operand being held constant. OPNO counts from 1. */
1196 static bool
1198 {
1200 {
1211 }
1212 }
1214 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1215 constant. We assume ARG1 and ARG2 have the same data type, or at least
1216 are the same kind of constant and the same machine mode. Return zero if
1217 combining the constants is not allowed in the current operating mode. */
1219 static tree
1221 {
1222 /* Sanity check for the recursive cases. */
1230 {
1236 }
1239 {
1240 machine_mode mode;
1241 REAL_VALUE_TYPE d1;
1242 REAL_VALUE_TYPE d2;
1243 REAL_VALUE_TYPE value;
1244 REAL_VALUE_TYPE result;
1248 /* The following codes are handled by real_arithmetic. */
1250 {
1261 }
1269 /* Don't perform operation if we honor signaling NaNs and
1270 either operand is a signaling NaN. */
1276 /* Don't perform operation if it would raise a division
1277 by zero exception. */
1283 /* If either operand is a NaN, just return it. Otherwise, set up
1284 for floating-point trap; we return an overflow. */
1286 {
1287 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1288 is off. */
1292 }
1294 {
1295 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1296 is off. */
1300 }
1305 /* Don't constant fold this floating point operation if
1306 the result has overflowed and flag_trapping_math. */
1314 /* Don't constant fold this floating point operation if the
1315 result may dependent upon the run-time rounding mode and
1316 flag_rounding_math is set, or if GCC's software emulation
1317 is unable to accurately represent the result. */
1327 }
1330 {
1331 FIXED_VALUE_TYPE f1;
1332 FIXED_VALUE_TYPE f2;
1333 FIXED_VALUE_TYPE result;
1338 /* The following codes are handled by fixed_arithmetic. */
1340 {
1352 {
1359 }
1364 }
1371 /* Propagate overflow flags. */
1375 }
1378 {
1387 {
1398 mpc_mul);
1412 mpc_div);
1413 /* Fallthru. */
1419 {
1420 /* Keep this algorithm in sync with
1421 tree-complex.c:expand_complex_div_straight().
1423 Expand complex division to scalars, straightforward algorithm.
1424 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1425 t = br*br + bi*bi
1426 */
1427 tree magsquared
1431 tree t1
1435 tree t2
1442 }
1443 else
1444 {
1445 /* Keep this algorithm in sync with
1446 tree-complex.c:expand_complex_div_wide().
1448 Expand complex division to scalars, modified algorithm to minimize
1449 overflow with wide input ranges. */
1455 {
1456 /* In the TRUE branch, we compute
1457 ratio = br/bi;
1458 div = (br * ratio) + bi;
1459 tr = (ar * ratio) + ai;
1460 ti = (ai * ratio) - ar;
1461 tr = tr / div;
1462 ti = ti / div; */
1473 }
1474 else
1475 {
1476 /* In the FALSE branch, we compute
1477 ratio = d/c;
1478 divisor = (d * ratio) + c;
1479 tr = (b * ratio) + a;
1480 ti = b - (a * ratio);
1481 tr = tr / div;
1482 ti = ti / div; */
1494 }
1495 }
1500 }
1504 }
1510 {
1515 /* We can operate directly on the encoding if:
1517 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1518 implies
1519 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1521 Addition and subtraction are the supported operators
1522 for which this is true. */
1525 /* We can operate directly on stepped encodings if:
1527 a3 - a2 == a2 - a1
1528 implies:
1529 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1531 which is true if (x -> x op c) distributes over addition. */
1533 else
1534 /* Similarly in reverse. */
1536 tree_vector_builder elts;
1541 {
1547 /* It is possible that const_binop cannot handle the given
1548 code and return NULL_TREE */
1552 }
1555 }
1557 /* Shifts allow a scalar offset for a vector. */
1560 {
1563 tree_vector_builder elts;
1568 {
1573 /* It is possible that const_binop cannot handle the given
1574 code and return NULL_TREE. */
1578 }
1581 }
1583 }
1585 /* Overload that adds a TYPE parameter to be able to dispatch
1586 to fold_relational_const. */
1588 tree
1590 {
1594 /* ??? Until we make the const_binop worker take the type of the
1595 result as argument put those cases that need it here. */
1597 {
1614 {
1619 }
1625 {
1641 {
1646 ? NOP_EXPR
1653 }
1656 }
1662 {
1685 {
1698 }
1701 }
1704 }
1709 /* Make sure type and arg0 have the same saturating flag. */
1714 }
1716 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1717 Return zero if computing the constants is not possible. */
1719 tree
1721 {
1722 /* Don't perform the operation, other than NEGATE and ABS, if
1723 flag_signaling_nans is on and the operand is a signaling NaN. */
1733 {
1734 CASE_CONVERT:
1741 /* If the source address is 0, and the source address space
1742 cannot have a valid object at 0, fold to dest type null. */
1753 {
1754 /* Can't call fold_negate_const directly here as that doesn't
1755 handle all cases and we might not be able to negate some
1756 constants. */
1761 }
1771 {
1775 }
1783 /* Perform BIT_NOT_EXPR on each element individually. */
1785 {
1786 tree elem;
1788 /* This can cope with stepped encodings because ~x == -1 - x. */
1789 tree_vector_builder elements;
1793 {
1799 }
1802 }
1826 {
1849 else
1854 {
1860 }
1863 }
1872 }
1875 }
1877 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1878 indicates which particular sizetype to create. */
1880 tree
1882 {
1884 }
1885 \f
1886 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1887 is a tree code. The type of the result is taken from the operands.
1888 Both must be equivalent integer types, ala int_binop_types_match_p.
1889 If the operands are constant, so is the result. */
1891 tree
1893 {
1902 /* Handle the special case of two poly_int constants faster. */
1904 {
1905 /* And some specific cases even faster than that. */
1907 {
1914 }
1916 {
1920 }
1922 {
1926 }
1928 /* Handle general case of two integer constants. For sizetype
1929 constant calculations we always want to know about overflow,
1930 even in the unsigned case. */
1934 }
1937 }
1939 /* Given two values, either both of sizetype or both of bitsizetype,
1940 compute the difference between the two values. Return the value
1941 in signed type corresponding to the type of the operands. */
1943 tree
1945 {
1947 tree ctype;
1952 /* If the type is already signed, just do the simple thing. */
1960 else
1963 /* If either operand is not a constant, do the conversions to the signed
1964 type and subtract. The hardware will do the right thing with any
1965 overflow in the subtraction. */
1971 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1972 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1973 overflow) and negate (which can't either). Special-case a result
1974 of zero while we're here. */
1980 else
1984 MINUS_EXPR,
1986 }
1987 \f
1988 /* A subroutine of fold_convert_const handling conversions of an
1989 INTEGER_CST to another integer type. */
1991 static tree
1993 {
1994 /* Given an integer constant, make new constant with new type,
1995 appropriately sign-extended or truncated. Use widest_int
1996 so that any extension is done according ARG1's type. */
2000 }
2002 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2003 to an integer type. */
2005 static tree
2007 {
2009 tree t;
2011 /* The following code implements the floating point to integer
2012 conversion rules required by the Java Language Specification,
2013 that IEEE NaNs are mapped to zero and values that overflow
2014 the target precision saturate, i.e. values greater than
2015 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2016 are mapped to INT_MIN. These semantics are allowed by the
2017 C and C++ standards that simply state that the behavior of
2018 FP-to-integer conversion is unspecified upon overflow. */
2020 wide_int val;
2021 REAL_VALUE_TYPE r;
2025 {
2032 }
2034 /* If R is NaN, return zero and show we have an overflow. */
2036 {
2039 }
2041 /* See if R is less than the lower bound or greater than the
2042 upper bound. */
2045 {
2049 {
2052 }
2053 }
2056 {
2059 {
2062 {
2065 }
2066 }
2067 }
2074 }
2076 /* A subroutine of fold_convert_const handling conversions of a
2077 FIXED_CST to an integer type. */
2079 static tree
2081 {
2082 tree t;
2084 scalar_mode mode;
2086 /* Right shift FIXED_CST to temp by fbit. */
2090 {
2092 HOST_BITS_PER_DOUBLE_INT,
2095 /* Left shift temp to temp_trunc by fbit. */
2097 HOST_BITS_PER_DOUBLE_INT,
2099 }
2100 else
2101 {
2104 }
2106 /* If FIXED_CST is negative, we need to round the value toward 0.
2107 By checking if the fractional bits are not zero to add 1 to temp. */
2113 /* Given a fixed-point constant, make new constant with new type,
2114 appropriately sign-extended or truncated. */
2122 }
2124 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2125 to another floating point type. */
2127 static tree
2129 {
2130 REAL_VALUE_TYPE value;
2131 tree t;
2133 /* Don't perform the operation if flag_signaling_nans is on
2134 and the operand is a signaling NaN. */
2142 /* If converting an infinity or NAN to a representation that doesn't
2143 have one, set the overflow bit so that we can produce some kind of
2144 error message at the appropriate point if necessary. It's not the
2145 most user-friendly message, but it's better than nothing. */
2152 /* Regular overflow, conversion produced an infinity in a mode that
2153 can't represent them. */
2158 else
2161 }
2163 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2164 to a floating point type. */
2166 static tree
2168 {
2169 REAL_VALUE_TYPE value;
2170 tree t;
2178 }
2180 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2181 to another fixed-point type. */
2183 static tree
2185 {
2186 FIXED_VALUE_TYPE value;
2187 tree t;
2194 /* Propagate overflow flags. */
2198 }
2200 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2201 to a fixed-point type. */
2203 static tree
2205 {
2206 FIXED_VALUE_TYPE value;
2207 tree t;
2209 double_int di;
2216 else
2224 /* Propagate overflow flags. */
2228 }
2230 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2231 to a fixed-point type. */
2233 static tree
2235 {
2236 FIXED_VALUE_TYPE value;
2237 tree t;
2245 /* Propagate overflow flags. */
2249 }
2251 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2252 type TYPE. If no simplification can be done return NULL_TREE. */
2254 static tree
2256 {
2261 /* We can't widen types, since the runtime value could overflow the
2262 original type before being extended to the new type. */
2273 {
2280 }
2282 {
2289 }
2291 {
2298 }
2300 {
2303 {
2306 /* We can't handle steps directly when extending, since the
2307 values need to wrap at the original precision first. */
2308 bool step_ok_p
2312 tree_vector_builder v;
2317 {
2323 }
2325 }
2326 }
2328 }
2330 /* Construct a vector of zero elements of vector type TYPE. */
2332 static tree
2334 {
2335 tree t;
2339 }
2341 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2343 bool
2345 {
2360 {
2382 }
2383 }
2385 /* Convert expression ARG to type TYPE. Used by the middle-end for
2386 simple conversions in preference to calling the front-end's convert. */
2388 tree
2390 {
2392 tree tem;
2403 {
2406 /* Handle conversions between pointers to different address spaces. */
2411 /* fall through */
2416 {
2420 }
2434 {
2438 }
2440 {
2444 }
2446 {
2450 }
2453 {
2471 }
2476 {
2480 }
2483 {
2497 }
2501 {
2510 integer_zero_node));
2512 {
2516 {
2522 }
2530 }
2534 }
2552 }
2553 fold_convert_exit:
2556 }
2557 \f
2558 /* Return false if expr can be assumed not to be an lvalue, true
2559 otherwise. */
2561 static bool
2563 {
2564 /* We only need to wrap lvalue tree codes. */
2566 {
2598 /* Assume the worst for front-end tree codes. */
2602 }
2605 }
2607 /* Return an expr equal to X but certainly not valid as an lvalue. */
2609 tree
2611 {
2612 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2613 us. */
2620 }
2622 /* When pedantic, return an expr equal to X but certainly not valid as a
2623 pedantic lvalue. Otherwise, return X. */
2625 static tree
2627 {
2629 }
2630 \f
2631 /* Given a tree comparison code, return the code that is the logical inverse.
2632 It is generally not safe to do this for floating-point comparisons, except
2633 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2634 ERROR_MARK in this case. */
2636 enum tree_code
2638 {
2644 {
2675 }
2676 }
2678 /* Similar, but return the comparison that results if the operands are
2679 swapped. This is safe for floating-point. */
2681 enum tree_code
2683 {
2685 {
2711 }
2712 }
2715 /* Convert a comparison tree code from an enum tree_code representation
2716 into a compcode bit-based encoding. This function is the inverse of
2717 compcode_to_comparison. */
2719 static enum comparison_code
2721 {
2723 {
2754 }
2755 }
2757 /* Convert a compcode bit-based encoding of a comparison operator back
2758 to GCC's enum tree_code representation. This function is the
2759 inverse of comparison_to_compcode. */
2761 static enum tree_code
2763 {
2765 {
2796 }
2797 }
2799 /* Return true if COND1 tests the opposite condition of COND2. */
2801 bool
2803 {
2806 && (invert_tree_comparison
2813 }
2815 /* Return a tree for the comparison which is the combination of
2816 doing the AND or OR (depending on CODE) of the two operations LCODE
2817 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2818 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2819 if this makes the transformation invalid. */
2821 tree
2826 {
2833 {
2844 }
2847 {
2848 /* Eliminate unordered comparisons, as well as LTGT and ORD
2849 which are not used unless the mode has NaNs. */
2855 }
2857 {
2858 /* Check that the original operation and the optimized ones will trap
2859 under the same condition. */
2870 /* In a short-circuited boolean expression the LHS might be
2871 such that the RHS, if evaluated, will never trap. For
2872 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2873 if neither x nor y is NaN. (This is a mixed blessing: for
2874 example, the expression above will never trap, hence
2875 optimizing it to x < y would be invalid). */
2880 /* If the comparison was short-circuited, and only the RHS
2881 trapped, we may now generate a spurious trap. */
2886 /* If we changed the conditions that cause a trap, we lose. */
2889 }
2895 else
2896 {
2901 }
2902 }
2903 \f
2904 /* Return nonzero if two operands (typically of the same tree node)
2905 are necessarily equal. FLAGS modifies behavior as follows:
2907 If OEP_ONLY_CONST is set, only return nonzero for constants.
2908 This function tests whether the operands are indistinguishable;
2909 it does not test whether they are equal using C's == operation.
2910 The distinction is important for IEEE floating point, because
2911 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2912 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2914 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2915 even though it may hold multiple values during a function.
2916 This is because a GCC tree node guarantees that nothing else is
2917 executed between the evaluation of its "operands" (which may often
2918 be evaluated in arbitrary order). Hence if the operands themselves
2919 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2920 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2921 unset means assuming isochronic (or instantaneous) tree equivalence.
2922 Unless comparing arbitrary expression trees, such as from different
2923 statements, this flag can usually be left unset.
2925 If OEP_PURE_SAME is set, then pure functions with identical arguments
2926 are considered the same. It is used when the caller has other ways
2927 to ensure that global memory is unchanged in between.
2929 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2930 not values of expressions.
2932 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2933 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2935 If OEP_BITWISE is set, then require the values to be bitwise identical
2936 rather than simply numerically equal. Do not take advantage of things
2937 like math-related flags or undefined behavior; only return true for
2938 values that are provably bitwise identical in all circumstances.
2940 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2941 any operand with side effect. This is unnecesarily conservative in the
2942 case we know that arg0 and arg1 are in disjoint code paths (such as in
2943 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2944 addresses with TREE_CONSTANT flag set so we know that &var == &var
2945 even if var is volatile. */
2947 bool
2950 {
2958 /* If either is ERROR_MARK, they aren't equal. */
2964 /* Similar, if either does not have a type (like a template id),
2965 they aren't equal. */
2969 /* Bitwise identity makes no sense if the values have different layouts. */
2974 /* We cannot consider pointers to different address space equal. */
2981 /* Check equality of integer constants before bailing out due to
2982 precision differences. */
2984 {
2985 /* Address of INTEGER_CST is not defined; check that we did not forget
2986 to drop the OEP_ADDRESS_OF flags. */
2989 }
2992 {
2993 /* If both types don't have the same signedness, then we can't consider
2994 them equal. We must check this before the STRIP_NOPS calls
2995 because they may change the signedness of the arguments. As pointers
2996 strictly don't have a signedness, require either two pointers or
2997 two non-pointers as well. */
3003 /* If both types don't have the same precision, then it is not safe
3004 to strip NOPs. */
3011 }
3012 #if 0
3013 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3014 sanity check once the issue is solved. */
3015 else
3016 /* Addresses of conversions and SSA_NAMEs (and many other things)
3017 are not defined. Check that we did not forget to drop the
3018 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3021 #endif
3023 /* In case both args are comparisons but with different comparison
3024 code, try to swap the comparison operands of one arg to produce
3025 a match and compare that variant. */
3029 {
3037 }
3040 {
3041 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3043 ;
3045 {
3046 /* If we are interested in comparing addresses ignore
3047 MEM_REF wrappings of the base that can appear just for
3048 TBAA reasons. */
3062 }
3063 else
3065 }
3067 /* When not checking adddresses, this is needed for conversions and for
3068 COMPONENT_REF. Might as well play it safe and always test this. */
3075 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3076 We don't care about side effects in that case because the SAVE_EXPR
3077 takes care of that for us. In all other cases, two expressions are
3078 equal if they have no side effects. If we have two identical
3079 expressions with side effects that should be treated the same due
3080 to the only side effects being identical SAVE_EXPR's, that will
3081 be detected in the recursive calls below.
3082 If we are taking an invariant address of two identical objects
3083 they are necessarily equal as well. */
3090 /* Next handle constant cases, those for which we can return 1 even
3091 if ONLY_CONST is set. */
3094 {
3107 {
3108 /* If we do not distinguish between signed and unsigned zero,
3109 consider them equal. */
3112 }
3116 {
3131 }
3135 flags)
3137 flags));
3148 flags | OEP_ADDRESS_OF
3151 /* In GIMPLE empty constructors are allowed in initializers of
3152 aggregates. */
3156 }
3158 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3159 two instances of undefined behavior will give identical results. */
3163 /* Define macros to test an operand from arg0 and arg1 for equality and a
3164 variant that allows null and views null as being different from any
3165 non-null value. In the latter case, if either is null, the both
3166 must be; otherwise, do the normal comparison. */
3167 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3168 TREE_OPERAND (arg1, N), flags)
3170 #define OP_SAME_WITH_NULL(N) \
3171 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3172 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3175 {
3177 /* Two conversions are equal only if signedness and modes match. */
3179 {
3180 CASE_CONVERT:
3188 }
3198 /* For commutative ops, allow the other order. */
3206 /* If either of the pointer (or reference) expressions we are
3207 dereferencing contain a side effect, these cannot be equal,
3208 but their addresses can be. */
3215 {
3218 {
3222 /* Verify that the access types are compatible. */
3226 }
3231 /* Require the same offset. */
3237 /* Fallthru. */
3245 {
3246 /* Require equal access sizes */
3252 flags)))
3254 /* Verify that access happens in similar types. */
3257 /* Verify that accesses are TBAA compatible. */
3266 /* Verify that alignment is compatible. */
3270 }
3273 /* TARGET_MEM_REF require equal extra operands. */
3284 /* Compare the array index by value if it is constant first as we
3285 may have different types but same value here. */
3291 /* Compare low bound and element size as with OEP_ADDRESS_OF
3292 we have to account for the offset of the ref. */
3297 array_ref_low_bound
3301 array_ref_element_size
3303 flags))));
3306 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3307 may be NULL when we're called to compare MEM_EXPRs. */
3310 {
3313 /* Most of time we only need to compare FIELD_DECLs for equality.
3314 However when determining address look into actual offsets.
3315 These may match for unions and unshared record types. */
3318 {
3320 {
3331 flags))
3333 }
3334 else
3336 }
3337 }
3348 }
3352 {
3354 /* Be sure we pass right ADDRESS_OF flag. */
3371 /* The multiplcation operands are commutative. */
3372 /* FALLTHRU */
3380 /* Otherwise take into account this is a commutative operation. */
3393 /* BIT_INSERT_EXPR has an implict operand as the type precision
3394 of op1. Need to check to make sure they are the same. */
3400 /* FALLTHRU */
3425 /* Virtual table reference. */
3437 {
3442 }
3447 }
3451 {
3455 /* If not both CALL_EXPRs are either internal or normal function
3456 functions, then they are not equal. */
3459 {
3460 /* If the CALL_EXPRs call different internal functions, then they
3461 are not equal. */
3464 }
3465 else
3466 {
3467 /* If the CALL_EXPRs call different functions, then they are not
3468 equal. */
3470 flags))
3472 }
3474 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3475 {
3479 else
3483 }
3485 /* Now see if all the arguments are the same. */
3486 {
3497 /* If we get here and both argument lists are exhausted
3498 then the CALL_EXPRs are equal. */
3500 }
3503 }
3506 /* Consider __builtin_sqrt equal to sqrt. */
3515 {
3519 /* In GIMPLE constructors are used only to build vectors from
3520 elements. Individual elements in the constructor must be
3521 indexed in increasing order and form an initial sequence.
3523 We make no effort to compare constructors in generic.
3524 (see sem_variable::equals in ipa-icf which can do so for
3525 constants). */
3530 /* Be sure that vectors constructed have the same representation.
3531 We only tested element precision and modes to match.
3532 Vectors may be BLKmode and thus also check that the number of
3533 parts match. */
3546 {
3551 /* In GIMPLE the indexes can be either NULL or matching i.
3552 Double check this so we won't get false
3553 positives for GENERIC. */
3561 }
3563 }
3566 {
3567 /* Compare the STATEMENT_LISTs. */
3573 {
3574 /* The lists don't have the same number of statements. */
3580 flags & (OEP_LEXICOGRAPHIC
3583 }
3584 }
3589 {
3600 }
3604 }
3606 #undef OP_SAME
3607 #undef OP_SAME_WITH_NULL
3608 }
3610 /* Generate a hash value for an expression. This can be used iteratively
3611 by passing a previous result as the HSTATE argument. */
3613 void
3616 {
3622 {
3625 }
3635 {
3636 /* Alas, constants aren't shared, so we can't rely on pointer
3637 identity. */
3647 {
3651 else
3655 }
3657 {
3661 }
3671 {
3678 }
3680 /* We can just compare by pointer. */
3684 /* The node itself doesn't matter. */
3688 /* Ignore. */
3691 /* A list of expressions, for a CALL_EXPR or as the elements of a
3692 VECTOR_CST. */
3697 {
3703 {
3704 /* In GIMPLE the indexes can be either NULL or matching i. */
3709 }
3711 }
3713 {
3714 tree_stmt_iterator i;
3719 }
3728 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3729 Otherwise nodes that compare equal according to operand_equal_p might
3730 get different hash codes. However, don't do this for machine specific
3731 or front end builtins, since the function code is overloaded in those
3732 cases. */
3735 {
3738 }
3739 /* FALL THROUGH */
3742 {
3746 }
3750 {
3751 /* DECL's have a unique ID */
3753 }
3755 {
3756 /* For comparisons that can be swapped, use the lower
3757 tree code. */
3764 }
3766 {
3767 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3768 operand_equal_p. */
3772 /* Don't hash the type, that can lead to having nodes which
3773 compare equal according to operand_equal_p, but which
3774 have different hash codes. Make sure to include signedness
3775 in the hash computation. */
3778 }
3779 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3787 /* Don't ICE on FE specific trees, or their arguments etc.
3788 during operand_equal_p hash verification. */
3791 else
3792 {
3798 {
3814 {
3819 else
3820 {
3826 }
3828 }
3842 {
3843 /* The multiplication operands are commutative. */
3850 }
3858 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
3859 Usually different TARGET_EXPRs just should use
3860 different temporaries in their slots. */
3865 /* Virtual table reference. */
3873 {
3875 /* We compute mangled names only when free_lang_data is run.
3876 In that case we can hash precisely. */
3879 hstate.add_object
3880 (IDENTIFIER_HASH_VALUE
3882 }
3886 }
3888 /* Don't hash the type, that can lead to having nodes which
3889 compare equal according to operand_equal_p, but which
3890 have different hash codes. */
3892 {
3893 /* Make sure to include signness in the hash computation. */
3896 }
3899 {
3900 /* It's a commutative expression. We want to hash it the same
3901 however it appears. We do this by first hashing both operands
3902 and then rehashing based on the order of their independent
3903 hashes. */
3908 }
3909 else
3913 }
3915 }
3916 }
3918 bool
3921 {
3922 /* When checking, verify at the outermost operand_equal_p call that
3923 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
3924 hash value. */
3926 {
3928 {
3930 {
3937 }
3939 }
3940 else
3944 }
3947 }
3952 /* Conveinece wrapper around operand_compare class because usually we do
3953 not need to play with the valueizer. */
3955 bool
3957 {
3959 }
3961 namespace inchash
3962 {
3964 /* Generate a hash value for an expression. This can be used iteratively
3965 by passing a previous result as the HSTATE argument.
3967 This function is intended to produce the same hash for expressions which
3968 would compare equal using operand_equal_p. */
3969 void
3971 {
3973 }
3975 }
3976 \f
3977 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3978 with a different signedness or a narrower precision. */
3980 static bool
3982 {
3990 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3991 and see if the inner values are the same. This removes any
3992 signedness comparison, which doesn't matter here. */
4000 /* Discard a single widening conversion from ARG1 and see if the inner
4001 value is the same as ARG0. */
4010 }
4011 \f
4012 /* See if ARG is an expression that is either a comparison or is performing
4013 arithmetic on comparisons. The comparisons must only be comparing
4014 two different values, which will be stored in *CVAL1 and *CVAL2; if
4015 they are nonzero it means that some operands have already been found.
4016 No variables may be used anywhere else in the expression except in the
4017 comparisons.
4019 If this is true, return 1. Otherwise, return zero. */
4021 static bool
4023 {
4027 /* We can handle some of the tcc_expression cases here. */
4036 {
4055 /* First see if we can handle the first operand, then the second. For
4056 the second operand, we know *CVAL1 can't be zero. It must be that
4057 one side of the comparison is each of the values; test for the
4058 case where this isn't true by failing if the two operands
4059 are the same. */
4068 ;
4072 ;
4073 else
4077 ;
4081 ;
4082 else
4089 }
4090 }
4091 \f
4092 /* ARG is a tree that is known to contain just arithmetic operations and
4093 comparisons. Evaluate the operations in the tree substituting NEW0 for
4094 any occurrence of OLD0 as an operand of a comparison and likewise for
4095 NEW1 and OLD1. */
4097 static tree
4100 {
4105 /* We can handle some of the tcc_expression cases here. */
4113 {
4128 {
4147 }
4148 /* Fall through - ??? */
4151 {
4155 /* We need to check both for exact equality and tree equality. The
4156 former will be true if the operand has a side-effect. In that
4157 case, we know the operand occurred exactly once. */
4170 }
4174 }
4175 }
4176 \f
4177 /* Return a tree for the case when the result of an expression is RESULT
4178 converted to TYPE and OMITTED was previously an operand of the expression
4179 but is now not needed (e.g., we folded OMITTED * 0).
4181 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4182 the conversion of RESULT to TYPE. */
4184 tree
4186 {
4189 /* If the resulting operand is an empty statement, just return the omitted
4190 statement casted to void. */
4200 }
4202 /* Return a tree for the case when the result of an expression is RESULT
4203 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4204 of the expression but are now not needed.
4206 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4207 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4208 evaluated before OMITTED2. Otherwise, if neither has side effects,
4209 just do the conversion of RESULT to TYPE. */
4211 tree
4214 {
4223 }
4225 \f
4226 /* Return a simplified tree node for the truth-negation of ARG. This
4227 never alters ARG itself. We assume that ARG is an operation that
4228 returns a truth value (0 or 1).
4230 FIXME: one would think we would fold the result, but it causes
4231 problems with the dominator optimizer. */
4233 static tree
4235 {
4240 /* If this is a comparison, we can simply invert it, except for
4241 floating-point non-equality comparisons, in which case we just
4242 enclose a TRUTH_NOT_EXPR around what we have. */
4245 {
4248 && flag_trapping_math
4262 }
4265 {
4284 /* Here we can invert either operand. We invert the first operand
4285 unless the second operand is a TRUTH_NOT_EXPR in which case our
4286 result is the XOR of the first operand with the inside of the
4287 negation of the second operand. */
4292 else
4315 {
4322 /* A COND_EXPR may have a throw as one operand, which
4323 then has void type. Just leave void operands
4324 as they are. */
4330 }
4342 CASE_CONVERT:
4346 /* fall through */
4368 }
4369 }
4371 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4372 assume that ARG is an operation that returns a truth value (0 or 1
4373 for scalars, 0 or -1 for vectors). Return the folded expression if
4374 folding is successful. Otherwise, return NULL_TREE. */
4376 static tree
4378 {
4381 ? BIT_NOT_EXPR
4384 }
4386 /* Return a simplified tree node for the truth-negation of ARG. This
4387 never alters ARG itself. We assume that ARG is an operation that
4388 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4390 tree
4392 {
4398 ? BIT_NOT_EXPR
4401 }
4402 \f
4403 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4404 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4405 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4406 is the original memory reference used to preserve the alias set of
4407 the access. */
4409 static tree
4413 {
4416 /* Attempt not to lose the access path if possible. */
4418 {
4420 machine_mode nmode;
4422 tree noffset;
4430 && !reversep
4431 && !nreversep
4433 {
4436 }
4437 }
4446 {
4453 }
4468 }
4470 /* Optimize a bit-field compare.
4472 There are two cases: First is a compare against a constant and the
4473 second is a comparison of two items where the fields are at the same
4474 bit position relative to the start of a chunk (byte, halfword, word)
4475 large enough to contain it. In these cases we can avoid the shift
4476 implicit in bitfield extractions.
4478 For constants, we emit a compare of the shifted constant with the
4479 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4480 compared. For two fields at the same position, we do the ANDs with the
4481 similar mask and compare the result of the ANDs.
4483 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4484 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4485 are the left and right operands of the comparison, respectively.
4487 If the optimization described above can be done, we return the resulting
4488 tree. Otherwise we return zero. */
4490 static tree
4493 {
4497 tree unsigned_type;
4500 scalar_int_mode nmode;
4505 tree mask;
4506 tree offset;
4508 /* Get all the information about the extractions being done. If the bit size
4509 is the same as the size of the underlying object, we aren't doing an
4510 extraction at all and so can do nothing. We also don't want to
4511 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4512 then will no longer be able to replace it. */
4527 else
4528 {
4529 /* If this is not a constant, we can only do something if bit positions,
4530 sizes, signedness and storage order are the same. */
4531 rinner
4544 }
4546 /* Honor the C++ memory model and mimic what RTL expansion does. */
4550 {
4554 }
4556 /* See if we can find a mode to refer to this field. We should be able to,
4557 but fail if we can't. */
4565 /* Set signed and unsigned types of the precision of this mode for the
4566 shifts below. */
4569 /* Compute the bit position and size for the new reference and our offset
4570 within it. If the new reference is the same size as the original, we
4571 won't optimize anything, so return zero. */
4581 /* Make the mask to be used against the extracted field. */
4588 {
4592 /* If not comparing with constant, just rework the comparison
4593 and return. */
4601 }
4603 /* Otherwise, we are handling the constant case. See if the constant is too
4604 big for the field. Warn and return a tree for 0 (false) if so. We do
4605 this not only for its own sake, but to avoid having to test for this
4606 error case below. If we didn't, we might generate wrong code.
4608 For unsigned fields, the constant shifted right by the field length should
4609 be all zero. For signed fields, the high-order bits should agree with
4610 the sign bit. */
4613 {
4615 {
4619 }
4620 }
4621 else
4622 {
4625 {
4629 }
4630 }
4635 /* Single-bit compares should always be against zero. */
4637 {
4640 }
4642 /* Make a new bitfield reference, shift the constant over the
4643 appropriate number of bits and mask it with the computed mask
4644 (in case this was a signed field). If we changed it, make a new one. */
4652 mask);
4657 }
4658 \f
4659 /* Subroutine for fold_truth_andor_1: decode a field reference.
4661 If EXP is a comparison reference, we return the innermost reference.
4663 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4664 set to the starting bit number.
4666 If the innermost field can be completely contained in a mode-sized
4667 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4669 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4670 otherwise it is not changed.
4672 *PUNSIGNEDP is set to the signedness of the field.
4674 *PREVERSEP is set to the storage order of the field.
4676 *PMASK is set to the mask used. This is either contained in a
4677 BIT_AND_EXPR or derived from the width of the field.
4679 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4681 Return 0 if this is not a component reference or is one that we can't
4682 do anything with. */
4684 static tree
4689 {
4694 tree unsigned_type;
4697 /* All the optimizations using this function assume integer fields.
4698 There are problems with FP fields since the type_for_size call
4699 below can fail for, e.g., XFmode. */
4703 /* We are interested in the bare arrangement of bits, so strip everything
4704 that doesn't affect the machine mode. However, record the type of the
4705 outermost expression if it may matter below. */
4712 {
4718 }
4729 /* Reject out-of-bound accesses (PR79731). */
4741 /* If the number of bits in the reference is the same as the bitsize of
4742 the outer type, then the outer type gives the signedness. Otherwise
4743 (in case of a small bitfield) the signedness is unchanged. */
4747 /* Compute the mask to access the bitfield. */
4755 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4763 }
4765 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4766 bit positions and MASK is SIGNED. */
4768 static bool
4770 {
4774 /* If this function returns true when the type of the mask is
4775 UNSIGNED, then there will be errors. In particular see
4776 gcc.c-torture/execute/990326-1.c. There does not appear to be
4777 any documentation paper trail as to why this is so. But the pre
4778 wide-int worked with that restriction and it has been preserved
4779 here. */
4784 }
4786 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4787 represents the sign bit of EXP's type. If EXP represents a sign
4788 or zero extension, also test VAL against the unextended type.
4789 The return value is the (sub)expression whose sign bit is VAL,
4790 or NULL_TREE otherwise. */
4792 tree
4794 {
4796 tree t;
4798 /* Tree EXP must have an integral type. */
4803 /* Tree VAL must be an integer constant. */
4812 /* Handle extension from a narrower type. */
4818 }
4820 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4821 to be evaluated unconditionally. */
4823 static bool
4825 {
4826 /* Strip any conversions that don't change the machine mode. */
4835 /* Don't regard global variables as simple. They may be
4836 allocated in ways unknown to the compiler (shared memory,
4837 #pragma weak, etc). */
4840 /* Weakrefs are not safe to be read, since they can be NULL.
4841 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4842 have DECL_WEAK flag set. */
4844 /* Loading a static variable is unduly expensive, but global
4845 registers aren't expensive. */
4847 }
4849 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4850 to be evaluated unconditionally.
4851 I addition to simple_operand_p, we assume that comparisons, conversions,
4852 and logic-not operations are simple, if their operands are simple, too. */
4854 static bool
4856 {
4875 }
4877 \f
4878 /* The following functions are subroutines to fold_range_test and allow it to
4879 try to change a logical combination of comparisons into a range test.
4881 For example, both
4882 X == 2 || X == 3 || X == 4 || X == 5
4883 and
4884 X >= 2 && X <= 5
4885 are converted to
4886 (unsigned) (X - 2) <= 3
4888 We describe each set of comparisons as being either inside or outside
4889 a range, using a variable named like IN_P, and then describe the
4890 range with a lower and upper bound. If one of the bounds is omitted,
4891 it represents either the highest or lowest value of the type.
4893 In the comments below, we represent a range by two numbers in brackets
4894 preceded by a "+" to designate being inside that range, or a "-" to
4895 designate being outside that range, so the condition can be inverted by
4896 flipping the prefix. An omitted bound is represented by a "-". For
4897 example, "- [-, 10]" means being outside the range starting at the lowest
4898 possible value and ending at 10, in other words, being greater than 10.
4899 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4900 always false.
4902 We set up things so that the missing bounds are handled in a consistent
4903 manner so neither a missing bound nor "true" and "false" need to be
4904 handled using a special case. */
4906 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4907 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4908 and UPPER1_P are nonzero if the respective argument is an upper bound
4909 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4910 must be specified for a comparison. ARG1 will be converted to ARG0's
4911 type if both are specified. */
4913 static tree
4916 {
4917 tree tem;
4921 /* If neither arg represents infinity, do the normal operation.
4922 Else, if not a comparison, return infinity. Else handle the special
4923 comparison rules. Note that most of the cases below won't occur, but
4924 are handled for consistency. */
4927 {
4932 }
4937 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4938 for neither. In real maths, we cannot assume open ended ranges are
4939 the same. But, this is computer arithmetic, where numbers are finite.
4940 We can therefore make the transformation of any unbounded range with
4941 the value Z, Z being greater than any representable number. This permits
4942 us to treat unbounded ranges as equal. */
4946 {
4967 }
4970 }
4971 \f
4972 /* Helper routine for make_range. Perform one step for it, return
4973 new expression if the loop should continue or NULL_TREE if it should
4974 stop. */
4976 tree
4980 {
4986 {
4988 /* We can only do something if the range is testing for zero. */
4997 /* We can only do something if the range is testing for zero
4998 and if the second operand is an integer constant. Note that
4999 saying something is "in" the range we make is done by
5000 complementing IN_P since it will set in the initial case of
5001 being not equal to zero; "out" is leaving it alone. */
5008 {
5029 }
5031 /* If this is an unsigned comparison, we also know that EXP is
5032 greater than or equal to zero. We base the range tests we make
5033 on that fact, so we record it here so we can parse existing
5034 range tests. We test arg0_type since often the return type
5035 of, e.g. EQ_EXPR, is boolean. */
5037 {
5041 NULL_TREE))
5046 /* If the high bound is missing, but we have a nonzero low
5047 bound, reverse the range so it goes from zero to the low bound
5048 minus 1. */
5050 {
5055 }
5056 }
5064 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5065 low and high are non-NULL, then normalize will DTRT. */
5068 {
5073 }
5075 /* (-x) IN [a,b] -> x in [-b, -a] */
5087 /* ~ X -> -X - 1 */
5096 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5097 move a constant to the other side. */
5102 /* If EXP is signed, any overflow in the computation is undefined,
5103 so we don't worry about it so long as our computations on
5104 the bounds don't overflow. For unsigned, overflow is defined
5105 and this is exactly the right thing. */
5117 normalize:
5118 /* Check for an unsigned range which has wrapped around the maximum
5119 value thus making n_high < n_low, and normalize it. */
5121 {
5127 /* If the range is of the form +/- [ x+1, x ], we won't
5128 be able to normalize it. But then, it represents the
5129 whole range or the empty set, so make it
5130 +/- [ -, - ]. */
5134 else
5136 }
5137 else
5145 CASE_CONVERT:
5163 /* If we're converting arg0 from an unsigned type, to exp,
5164 a signed type, we will be doing the comparison as unsigned.
5165 The tests above have already verified that LOW and HIGH
5166 are both positive.
5168 So we have to ensure that we will handle large unsigned
5169 values the same way that the current signed bounds treat
5170 negative values. */
5173 {
5174 tree high_positive;
5175 tree equiv_type;
5176 /* For fixed-point modes, we need to pass the saturating flag
5177 as the 2nd parameter. */
5179 equiv_type
5182 else
5183 equiv_type
5186 /* A range without an upper bound is, naturally, unbounded.
5187 Since convert would have cropped a very large value, use
5188 the max value for the destination type. */
5189 high_positive
5196 high_positive),
5199 /* If the low bound is specified, "and" the range with the
5200 range for which the original unsigned value will be
5201 positive. */
5203 {
5206 integer_zero_node),
5207 high_positive))
5211 }
5212 else
5213 {
5214 /* Otherwise, "or" the range with the range of the input
5215 that will be interpreted as negative. */
5218 integer_zero_node),
5219 high_positive))
5223 }
5224 }
5233 }
5234 }
5236 /* Given EXP, a logical expression, set the range it is testing into
5237 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5238 actually being tested. *PLOW and *PHIGH will be made of the same
5239 type as the returned expression. If EXP is not a comparison, we
5240 will most likely not be returning a useful value and range. Set
5241 *STRICT_OVERFLOW_P to true if the return value is only valid
5242 because signed overflow is undefined; otherwise, do not change
5243 *STRICT_OVERFLOW_P. */
5245 tree
5248 {
5256 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5257 and see if we can refine the range. Some of the cases below may not
5258 happen, but it doesn't seem worth worrying about this. We "continue"
5259 the outer loop when we've changed something; otherwise we "break"
5260 the switch, which will "break" the while. */
5266 {
5272 {
5280 }
5289 }
5291 /* If EXP is a constant, we can evaluate whether this is true or false. */
5293 {
5300 }
5304 }
5306 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5307 a bitwise check i.e. when
5308 LOW == 0xXX...X00...0
5309 HIGH == 0xXX...X11...1
5310 Return corresponding mask in MASK and stem in VALUE. */
5312 static bool
5315 {
5338 }
5339 \f
5340 /* Helper routine for build_range_check and match.pd. Return the type to
5341 perform the check or NULL if it shouldn't be optimized. */
5343 tree
5345 {
5346 /* First make sure that arithmetics in this type is valid, then make sure
5347 that it wraps around. */
5352 {
5355 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5356 for the type in question, as we rely on this here. */
5366 else
5368 }
5372 }
5374 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5375 type, TYPE, return an expression to test if EXP is in (or out of, depending
5376 on IN_P) the range. Return 0 if the test couldn't be created. */
5378 tree
5381 {
5384 /* Disable this optimization for function pointer expressions
5385 on targets that require function pointer canonicalization. */
5392 {
5398 }
5420 value);
5423 {
5425 {
5429 }
5431 }
5433 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5435 {
5439 {
5441 {
5444 etype
5446 else
5449 }
5452 }
5453 }
5455 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5456 This requires wrap-around arithmetics for the type of the expression. */
5473 }
5474 \f
5475 /* Return the predecessor of VAL in its type, handling the infinite case. */
5477 static tree
5479 {
5485 else
5488 }
5490 /* Return the successor of VAL in its type, handling the infinite case. */
5492 static tree
5494 {
5500 else
5503 }
5505 /* Given two ranges, see if we can merge them into one. Return 1 if we
5506 can, 0 if we can't. Set the output range into the specified parameters. */
5508 bool
5511 {
5515 tree tem;
5525 /* Make range 0 be the range that starts first, or ends last if they
5526 start at the same value. Swap them if it isn't. */
5529 || (lowequal
5532 {
5536 }
5538 /* If the second range is != high1 where high1 is the type maximum of
5539 the type, try first merging with < high1 range. */
5541 && high1
5548 {
5553 /* Similarly for the second range != low1 where low1 is the type minimum
5554 of the type, try first merging with > low1 range. */
5559 }
5561 /* Now flag two cases, whether the ranges are disjoint or whether the
5562 second range is totally subsumed in the first. Note that the tests
5563 below are simplified by the ones above. */
5569 /* We now have four cases, depending on whether we are including or
5570 excluding the two ranges. */
5572 {
5573 /* If they don't overlap, the result is false. If the second range
5574 is a subset it is the result. Otherwise, the range is from the start
5575 of the second to the end of the first. */
5580 else
5582 }
5585 {
5586 /* If they don't overlap, the result is the first range. If they are
5587 equal, the result is false. If the second range is a subset of the
5588 first, and the ranges begin at the same place, we go from just after
5589 the end of the second range to the end of the first. If the second
5590 range is not a subset of the first, or if it is a subset and both
5591 ranges end at the same place, the range starts at the start of the
5592 first range and ends just before the second range.
5593 Otherwise, we can't describe this as a single range. */
5599 {
5604 {
5605 /* We are in the weird situation where high0 > high1 but
5606 high1 has no successor. Punt. */
5608 }
5609 }
5611 {
5616 {
5617 /* low0 < low1 but low1 has no predecessor. Punt. */
5619 }
5620 }
5621 else
5623 }
5626 {
5627 /* If they don't overlap, the result is the second range. If the second
5628 is a subset of the first, the result is false. Otherwise,
5629 the range starts just after the first range and ends at the
5630 end of the second. */
5635 else
5636 {
5641 {
5642 /* high1 > high0 but high0 has no successor. Punt. */
5644 }
5645 }
5646 }
5648 else
5649 {
5650 /* The case where we are excluding both ranges. Here the complex case
5651 is if they don't overlap. In that case, the only time we have a
5652 range is if they are adjacent. If the second is a subset of the
5653 first, the result is the first. Otherwise, the range to exclude
5654 starts at the beginning of the first range and ends at the end of the
5655 second. */
5657 {
5662 else
5663 {
5664 /* Canonicalize - [min, x] into - [-, x]. */
5667 {
5670 GET_MODE_BITSIZE
5673 /* FALLTHROUGH */
5686 }
5688 /* Canonicalize - [x, max] into - [x, -]. */
5691 {
5694 GET_MODE_BITSIZE
5697 /* FALLTHROUGH */
5713 }
5715 /* The ranges might be also adjacent between the maximum and
5716 minimum values of the given type. For
5717 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5718 return + [x + 1, y - 1]. */
5720 {
5727 }
5728 else
5730 }
5731 }
5734 else
5736 }
5740 }
5741 \f
5743 /* Subroutine of fold, looking inside expressions of the form
5744 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5745 of the COND_EXPR. This function is being used also to optimize
5746 A op B ? C : A, by reversing the comparison first.
5748 Return a folded expression whose code is not a COND_EXPR
5749 anymore, or NULL_TREE if no folding opportunity is found. */
5751 static tree
5754 {
5759 tree tem;
5764 /* If we have A op 0 ? A : -A, consider applying the following
5765 transformations:
5767 A == 0? A : -A same as -A
5768 A != 0? A : -A same as A
5769 A >= 0? A : -A same as abs (A)
5770 A > 0? A : -A same as abs (A)
5771 A <= 0? A : -A same as -abs (A)
5772 A < 0? A : -A same as -abs (A)
5774 None of these transformations work for modes with signed
5775 zeros. If A is +/-0, the first two transformations will
5776 change the sign of the result (from +0 to -0, or vice
5777 versa). The last four will fix the sign of the result,
5778 even though the original expressions could be positive or
5779 negative, depending on the sign of A.
5781 Note that all these transformations are correct if A is
5782 NaN, since the two alternatives (A and -A) are also NaNs. */
5789 /* In the case that A is of the form X-Y, '-A' (arg2) may
5790 have already been folded to Y-X, check for that. */
5798 {
5810 /* Fall through. */
5821 /* FALLTHRU */
5828 {
5829 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
5830 is not, invokes UB both in abs and in the negation of it.
5831 So, use ABSU_EXPR instead. */
5836 }
5837 else
5838 {
5841 }
5845 }
5847 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5848 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5849 both transformations are correct when A is NaN: A != 0
5850 is then true, and A == 0 is false. */
5854 {
5859 }
5861 /* Try some transformations of A op B ? A : B.
5863 A == B? A : B same as B
5864 A != B? A : B same as A
5865 A >= B? A : B same as max (A, B)
5866 A > B? A : B same as max (B, A)
5867 A <= B? A : B same as min (A, B)
5868 A < B? A : B same as min (B, A)
5870 As above, these transformations don't work in the presence
5871 of signed zeros. For example, if A and B are zeros of
5872 opposite sign, the first two transformations will change
5873 the sign of the result. In the last four, the original
5874 expressions give different results for (A=+0, B=-0) and
5875 (A=-0, B=+0), but the transformed expressions do not.
5877 The first two transformations are correct if either A or B
5878 is a NaN. In the first transformation, the condition will
5879 be false, and B will indeed be chosen. In the case of the
5880 second transformation, the condition A != B will be true,
5881 and A will be chosen.
5883 The conversions to max() and min() are not correct if B is
5884 a number and A is not. The conditions in the original
5885 expressions will be false, so all four give B. The min()
5886 and max() versions would give a NaN instead. */
5889 /* Avoid these transformations if the COND_EXPR may be used
5890 as an lvalue in the C++ front-end. PR c++/19199. */
5891 && (in_gimple_form
5897 {
5903 {
5912 /* In C++ a ?: expression can be an lvalue, so put the
5913 operand which will be used if they are equal first
5914 so that we can convert this back to the
5915 corresponding COND_EXPR. */
5917 {
5925 }
5932 {
5940 }
5953 }
5954 }
5957 }
5960 \f
5961 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5962 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5963 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5964 false) >= 2)
5965 #endif
5967 /* EXP is some logical combination of boolean tests. See if we can
5968 merge it into some range test. Return the new tree if so. */
5970 static tree
5973 {
5987 /* If op0 is known true or false and this is a short-circuiting
5988 operation we must not merge with op1 since that makes side-effects
5989 unconditional. So special-case this. */
5996 /* If this is an OR operation, invert both sides; we will invert
5997 again at the end. */
6001 /* If both expressions are the same, if we can merge the ranges, and we
6002 can build the range test, return it or it inverted. If one of the
6003 ranges is always true or always false, consider it to be the same
6004 expression as the other. */
6012 {
6016 }
6018 /* On machines where the branch cost is expensive, if this is a
6019 short-circuited branch and the underlying object on both sides
6020 is the same, make a non-short-circuit operation. */
6023 logical_op_non_short_circuit
6026 && !flag_sanitize_coverage
6030 {
6031 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6032 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6033 which cases we can't do this. */
6041 {
6050 {
6053 WARN_STRICT_OVERFLOW_COMPARISON);
6057 }
6058 }
6059 }
6062 }
6063 \f
6064 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6065 bit value. Arrange things so the extra bits will be set to zero if and
6066 only if C is signed-extended to its full width. If MASK is nonzero,
6067 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6069 static tree
6071 {
6074 tree temp;
6079 /* We work by getting just the sign bit into the low-order bit, then
6080 into the high-order bit, then sign-extend. We then XOR that value
6081 with C. */
6085 /* We must use a signed type in order to get an arithmetic right shift.
6086 However, we must also avoid introducing accidental overflows, so that
6087 a subsequent call to integer_zerop will work. Hence we must
6088 do the type conversion here. At this point, the constant is either
6089 zero or one, and the conversion to a signed type can never overflow.
6090 We could get an overflow if this conversion is done anywhere else. */
6099 /* If necessary, convert the type back to match the type of C. */
6104 }
6105 \f
6106 /* For an expression that has the form
6107 (A && B) || ~B
6108 or
6109 (A || B) && ~B,
6110 we can drop one of the inner expressions and simplify to
6111 A || ~B
6112 or
6113 A && ~B
6114 LOC is the location of the resulting expression. OP is the inner
6115 logical operation; the left-hand side in the examples above, while CMPOP
6116 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6117 removing a condition that guards another, as in
6118 (A != NULL && A->...) || A == NULL
6119 which we must not transform. If RHS_ONLY is true, only eliminate the
6120 right-most operand of the inner logical operation. */
6122 static tree
6125 {
6143 {
6146 {
6149 }
6150 }
6152 {
6155 {
6158 }
6159 }
6174 }
6176 /* Find ways of folding logical expressions of LHS and RHS:
6177 Try to merge two comparisons to the same innermost item.
6178 Look for range tests like "ch >= '0' && ch <= '9'".
6179 Look for combinations of simple terms on machines with expensive branches
6180 and evaluate the RHS unconditionally.
6182 For example, if we have p->a == 2 && p->b == 4 and we can make an
6183 object large enough to span both A and B, we can do this with a comparison
6184 against the object ANDed with the a mask.
6186 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6187 operations to do this with one comparison.
6189 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6190 function and the one above.
6192 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6193 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6195 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6196 two operands.
6198 We return the simplified tree or 0 if no optimization is possible. */
6200 static tree
6203 {
6204 /* If this is the "or" of two comparisons, we can do something if
6205 the comparisons are NE_EXPR. If this is the "and", we can do something
6206 if the comparisons are EQ_EXPR. I.e.,
6207 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6209 WANTED_CODE is this operation code. For single bit fields, we can
6210 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6211 comparison for one-bit fields. */
6232 /* Start by getting the comparison codes. Fail if anything is volatile.
6233 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6234 it were surrounded with a NE_EXPR. */
6243 {
6247 }
6250 {
6254 }
6265 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6268 {
6271 {
6276 }
6279 {
6285 }
6286 }
6291 /* If the RHS can be evaluated unconditionally and its operands are
6292 simple, it wins to evaluate the RHS unconditionally on machines
6293 with expensive branches. In this case, this isn't a comparison
6294 that can be merged. */
6301 {
6302 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6313 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6323 }
6325 /* See if the comparisons can be merged. Then get all the parameters for
6326 each side. */
6351 /* It must be true that the inner operation on the lhs of each
6352 comparison must be the same if we are to be able to do anything.
6353 Then see if we have constants. If not, the same must be true for
6354 the rhs's. */
6363 {
6366 }
6371 else
6374 /* If either comparison code is not correct for our logical operation,
6375 fail. However, we can convert a one-bit comparison against zero into
6376 the opposite comparison against that bit being set in the field. */
6380 {
6382 {
6383 /* Make the left operand unsigned, since we are only interested
6384 in the value of one bit. Otherwise we are doing the wrong
6385 thing below. */
6388 }
6389 else
6391 }
6393 /* This is analogous to the code for l_const above. */
6395 {
6397 {
6400 }
6401 else
6403 }
6405 /* See if we can find a mode that contains both fields being compared on
6406 the left. If we can't, fail. Otherwise, update all constants and masks
6407 to be relative to a field of that size. */
6421 {
6424 }
6432 {
6439 {
6443 }
6444 }
6446 {
6453 {
6457 }
6458 }
6460 /* If the right sides are not constant, do the same for it. Also,
6461 disallow this optimization if a size, signedness or storage order
6462 mismatch occurs between the left and right sides. */
6464 {
6468 /* Make sure the two fields on the right
6469 correspond to the left without being swapped. */
6486 {
6489 }
6498 /* Make a mask that corresponds to both fields being compared.
6499 Do this for both items being compared. If the operands are the
6500 same size and the bits being compared are in the same position
6501 then we can do this by masking both and comparing the masked
6502 results. */
6509 {
6523 }
6525 /* There is still another way we can do something: If both pairs of
6526 fields being compared are adjacent, we may be able to make a wider
6527 field containing them both.
6529 Note that we still must mask the lhs/rhs expressions. Furthermore,
6530 the mask must be shifted to account for the shift done by
6531 make_bit_field_ref. */
6540 {
6541 tree type;
6557 /* Convert to the smaller type before masking out unwanted bits. */
6560 {
6562 {
6566 }
6568 {
6572 }
6573 }
6582 }
6585 }
6587 /* Handle the case of comparisons with constants. If there is something in
6588 common between the masks, those bits of the constants must be the same.
6589 If not, the condition is always false. Test for this to avoid generating
6590 incorrect code below. */
6595 {
6597 {
6600 }
6601 else
6602 {
6605 }
6606 }
6611 /* Construct the expression we will return. First get the component
6612 reference we will make. Unless the mask is all ones the width of
6613 that field, perform the mask operation. Then compare with the
6614 merged constant. */
6625 }
6626 \f
6627 /* T is an integer expression that is being multiplied, divided, or taken a
6628 modulus (CODE says which and what kind of divide or modulus) by a
6629 constant C. See if we can eliminate that operation by folding it with
6630 other operations already in T. WIDE_TYPE, if non-null, is a type that
6631 should be used for the computation if wider than our type.
6633 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6634 (X * 2) + (Y * 4). We must, however, be assured that either the original
6635 expression would not overflow or that overflow is undefined for the type
6636 in the language in question.
6638 If we return a non-null expression, it is an equivalent form of the
6639 original computation, but need not be in the original type.
6641 We set *STRICT_OVERFLOW_P to true if the return values depends on
6642 signed overflow being undefined. Otherwise we do not change
6643 *STRICT_OVERFLOW_P. */
6645 static tree
6648 {
6649 /* To avoid exponential search depth, refuse to allow recursion past
6650 three levels. Beyond that (1) it's highly unlikely that we'll find
6651 something interesting and (2) we've probably processed it before
6652 when we built the inner expression. */
6655 tree ret;
6660 depth++;
6662 depth--;
6665 }
6667 static tree
6670 {
6682 /* Don't deal with constants of zero here; they confuse the code below. */
6692 /* Note that we need not handle conditional operations here since fold
6693 already handles those cases. So just do arithmetic here. */
6695 {
6697 /* For a constant, we can always simplify if we are a multiply
6698 or (for divide and modulus) if it is a multiple of our constant. */
6702 {
6705 /* If the multiplication overflowed, we lost information on it.
6706 See PR68142 and PR69845. */
6710 }
6714 /* If op0 is an expression ... */
6720 /* ... and has wrapping overflow, and its type is smaller
6721 than ctype, then we cannot pass through as widening. */
6726 /* ... or this is a truncation (t is narrower than op0),
6727 then we cannot pass through this narrowing. */
6730 /* ... or signedness changes for division or modulus,
6731 then we cannot pass through this conversion. */
6735 /* ... or has undefined overflow while the converted to
6736 type has not, we cannot do the operation in the inner type
6737 as that would introduce undefined overflow. */
6743 /* Pass the constant down and see if we can make a simplification. If
6744 we can, replace this expression with the inner simplification for
6745 possible later conversion to our or some other type. */
6756 /* If widening the type changes it from signed to unsigned, then we
6757 must avoid building ABS_EXPR itself as unsigned. */
6759 {
6763 {
6766 }
6768 }
6769 /* If the constant is negative, we cannot simplify this. */
6772 /* FALLTHROUGH */
6774 /* For division and modulus, type can't be unsigned, as e.g.
6775 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6776 For signed types, even with wrapping overflow, this is fine. */
6785 /* If widening the type changes the signedness, then we can't perform
6786 this optimization as that changes the result. */
6790 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6796 {
6803 }
6807 /* If the second operand is constant, this is a multiplication
6808 or floor division, by a power of two, so we can treat it that
6809 way unless the multiplier or divisor overflows. Signed
6810 left-shift overflow is implementation-defined rather than
6811 undefined in C90, so do not convert signed left shift into
6812 multiplication. */
6815 /* const_binop may not detect overflow correctly,
6816 so check for it explicitly here. */
6825 ctype,
6827 t1),
6832 /* See if we can eliminate the operation on both sides. If we can, we
6833 can return a new PLUS or MINUS. If we can't, the only remaining
6834 cases where we can do anything are if the second operand is a
6835 constant. */
6842 /* If not multiplication, we can only do this if both operands
6843 are divisible by c. */
6846 {
6851 }
6853 /* If this was a subtraction, negate OP1 and set it to be an addition.
6854 This simplifies the logic below. */
6856 {
6858 /* If OP1 was not easily negatable, the constant may be OP0. */
6860 {
6863 }
6864 }
6869 /* If either OP1 or C are negative, this optimization is not safe for
6870 some of the division and remainder types while for others we need
6871 to change the code. */
6873 {
6881 }
6883 /* If it's a multiply or a division/modulus operation of a multiple
6884 of our constant, do the operation and verify it doesn't overflow. */
6888 {
6891 /* We allow the constant to overflow with wrapping semantics. */
6895 }
6896 else
6899 /* If we have an unsigned type, we cannot widen the operation since it
6900 will change the result if the original computation overflowed. */
6904 /* The last case is if we are a multiply. In that case, we can
6905 apply the distributive law to commute the multiply and addition
6906 if the multiplication of the constants doesn't overflow
6907 and overflow is defined. With undefined overflow
6908 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
6909 But fold_plusminus_mult_expr would factor back any power-of-two
6910 value so do not distribute in the first place in this case. */
6918 op1);
6923 /* We have a special case here if we are doing something like
6924 (C * 8) % 4 since we know that's zero. */
6927 /* If the multiplication can overflow we cannot optimize this. */
6932 {
6935 }
6937 /* ... fall through ... */
6941 /* If we can extract our operation from the LHS, do so and return a
6942 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6943 do something only if the second operand is a constant. */
6959 /* If these are the same operation types, we can associate them
6960 assuming no overflow. */
6962 {
6977 }
6979 /* If these operations "cancel" each other, we have the main
6980 optimizations of this pass, which occur when either constant is a
6981 multiple of the other, in which case we replace this with either an
6982 operation or CODE or TCODE.
6984 If we have an unsigned type, we cannot do this since it will change
6985 the result if the original computation overflowed. */
6992 {
6995 {
7002 }
7005 {
7012 }
7013 }
7018 }
7021 }
7022 \f
7023 /* Return a node which has the indicated constant VALUE (either 0 or
7024 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7025 and is of the indicated TYPE. */
7027 tree
7029 {
7038 else
7040 }
7043 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7044 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7045 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7046 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7047 COND is the first argument to CODE; otherwise (as in the example
7048 given here), it is the second argument. TYPE is the type of the
7049 original expression. Return NULL_TREE if no simplification is
7050 possible. */
7052 static tree
7057 {
7065 /* Do not move possibly trapping operations into the conditional as this
7066 pessimizes code and causes gimplification issues when applied late. */
7074 {
7078 /* If this operand throws an expression, then it does not make
7079 sense to try to perform a logical or arithmetic operation
7080 involving it. */
7085 }
7088 {
7093 }
7094 else
7095 /* Detect the case of mixing vector and scalar types - bail out. */
7101 /* This transformation is only worthwhile if we don't have to wrap ARG
7102 in a SAVE_EXPR and the operation can be simplified without recursing
7103 on at least one of the branches once its pushed inside the COND_EXPR. */
7112 {
7116 else
7118 }
7120 {
7124 else
7126 }
7128 /* Check that we have simplified at least one of the branches. */
7133 }
7135 \f
7136 /* Subroutine of fold() that checks for the addition of +/- 0.0.
7138 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
7139 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
7140 ADDEND is the same as X.
7142 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7143 and finite. The problematic cases are when X is zero, and its mode
7144 has signed zeros. In the case of rounding towards -infinity,
7145 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7146 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7148 bool
7150 {
7154 /* Don't allow the fold with -fsignaling-nans. */
7158 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7162 /* There is no case that is safe for all rounding modes. */
7166 /* In a vector or complex, we would need to check the sign of all zeros. */
7172 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7176 /* The mode has signed zeros, and we have to honor their sign.
7177 In this situation, there is only one case we can return true for.
7178 X - 0 is the same as X with default rounding. */
7180 }
7182 /* Subroutine of match.pd that optimizes comparisons of a division by
7183 a nonzero integer constant against an integer constant, i.e.
7184 X/C1 op C2.
7186 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7187 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7189 enum tree_code
7192 {
7197 /* We have to do this the hard way to detect unsigned overflow.
7198 prod = int_const_binop (MULT_EXPR, c1, c2); */
7204 {
7208 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7211 }
7213 {
7216 {
7235 }
7236 }
7237 else
7238 {
7239 /* A negative divisor reverses the relational operators. */
7244 {
7263 }
7264 }
7277 }
7280 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7281 equality/inequality test, then return a simplified form of the test
7282 using a sign testing. Otherwise return NULL. TYPE is the desired
7283 result type. */
7285 static tree
7288 tree result_type)
7289 {
7290 /* If this is testing a single bit, we can optimize the test. */
7294 {
7295 /* If we have (A & C) != 0 where C is the sign bit of A, convert
7296 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
7300 /* This is only a win if casting to a signed type is cheap,
7301 i.e. when arg00's type is not a partial mode. */
7303 {
7306 result_type,
7309 }
7310 }
7313 }
7315 /* If CODE with arguments ARG0 and ARG1 represents a single bit
7316 equality/inequality test, then return a simplified form of
7317 the test using shifts and logical operations. Otherwise return
7318 NULL. TYPE is the desired result type. */
7320 tree
7323 {
7324 /* If this is testing a single bit, we can optimize the test. */
7328 {
7337 /* First, see if we can fold the single bit test into a sign-bit
7338 test. */
7340 result_type);
7344 /* Otherwise we have (A & C) != 0 where C is a single bit,
7345 convert that into ((A >> C2) & 1). Where C2 = log2(C).
7346 Similarly for (A & C) == 0. */
7348 /* If INNER is a right shift of a constant and it plus BITNUM does
7349 not overflow, adjust BITNUM and INNER. */
7355 {
7358 }
7360 /* If we are going to be able to omit the AND below, we must do our
7361 operations as unsigned. If we must use the AND, we have a choice.
7362 Normally unsigned is faster, but for some machines signed is. */
7380 /* Put the AND last so it can combine with more things. */
7383 /* Make sure to return the proper type. */
7387 }
7389 }
7391 /* Test whether it is preferable two swap two operands, ARG0 and
7392 ARG1, for example because ARG0 is an integer constant and ARG1
7393 isn't. */
7395 bool
7397 {
7411 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7412 for commutative and comparison operators. Ensuring a canonical
7413 form allows the optimizers to find additional redundancies without
7414 having to explicitly check for both orderings. */
7420 /* Put SSA_NAMEs last. */
7426 /* Put variables last. */
7433 }
7436 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7437 means A >= Y && A != MAX, but in this case we know that
7438 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7440 static tree
7442 {
7449 else
7458 {
7461 }
7463 {
7466 }
7467 else
7474 {
7475 /* Convert the pointer types into integer before taking the difference. */
7479 }
7480 else
7487 }
7489 /* Fold a sum or difference of at least one multiplication.
7490 Returns the folded tree or NULL if no simplification could be made. */
7492 static tree
7495 {
7499 /* (A * C) +- (B * C) -> (A+-B) * C.
7500 (A * C) +- A -> A * (C+-1).
7501 We are most concerned about the case where C is a constant,
7502 but other combinations show up during loop reduction. Since
7503 it is not difficult, try all four possibilities. */
7506 {
7509 }
7511 {
7514 }
7515 else
7516 {
7517 /* We cannot generate constant 1 for fract. */
7522 }
7524 {
7527 }
7529 {
7531 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7532 the purpose of this canonicalization. */
7536 {
7539 }
7540 else
7542 }
7543 else
7544 {
7545 /* We cannot generate constant 1 for fract. */
7550 }
7553 /* Prefer factoring a common non-constant. */
7563 /* No identical multiplicands; see if we can find a common
7564 power-of-two factor in non-power-of-two multiplies. This
7565 can help in multi-dimensional array access. */
7567 {
7570 HOST_WIDE_INT tmp;
7572 tree maybe_same;
7574 /* Move min of absolute values to int11. */
7576 {
7581 }
7582 else
7589 /* The remainder should not be a constant, otherwise we
7590 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7591 increased the number of multiplications necessary. */
7593 {
7601 }
7602 }
7609 /* We are neither factoring zero nor minus one. */
7617 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7618 same may be minus one and thus the multiplication may overflow. Perform
7619 the sum operation in an unsigned type. */
7624 /* If the sum evaluated to a constant that is not -INF the multiplication
7625 cannot overflow. */
7632 /* Do not resort to unsigned multiplication because
7633 we lose the no-overflow property of the expression. */
7635 }
7637 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7638 specified by EXPR into the buffer PTR of length LEN bytes.
7639 Return the number of bytes placed in the buffer, or zero
7640 upon failure. */
7642 static int
7644 {
7656 /* Dry run. */
7662 {
7664 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7665 number of bytes. */
7669 {
7676 else
7678 }
7679 else
7683 }
7685 }
7688 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7689 specified by EXPR into the buffer PTR of length LEN bytes.
7690 Return the number of bytes placed in the buffer, or zero
7691 upon failure. */
7693 static int
7695 {
7699 FIXED_VALUE_TYPE value;
7714 }
7717 /* Subroutine of native_encode_expr. Encode the REAL_CST
7718 specified by EXPR into the buffer PTR of length LEN bytes.
7719 Return the number of bytes placed in the buffer, or zero
7720 upon failure. */
7722 static int
7724 {
7730 /* There are always 32 bits in each long, no matter the size of
7731 the hosts long. We handle floating point representations with
7732 up to 192 bits. */
7741 /* Dry run. */
7750 {
7755 {
7762 else
7764 }
7765 else
7766 {
7769 {
7770 /* Reverse bytes within each long, or within the entire float
7771 if it's smaller than a long (for HFmode). */
7774 }
7775 }
7780 }
7782 }
7784 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7785 specified by EXPR into the buffer PTR of length LEN bytes.
7786 Return the number of bytes placed in the buffer, or zero
7787 upon failure. */
7789 static int
7791 {
7793 tree part;
7807 }
7809 /* Like native_encode_vector, but only encode the first COUNT elements.
7810 The other arguments are as for native_encode_vector. */
7812 static int
7815 {
7819 {
7820 /* This is the only case in which elements can be smaller than a byte.
7821 Element 0 is always in the lsb of the containing byte. */
7830 /* Zero the buffer and then set bits later where necessary. */
7839 {
7845 {
7848 }
7849 }
7851 }
7856 {
7858 {
7861 }
7872 }
7874 }
7876 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7877 specified by EXPR into the buffer PTR of length LEN bytes.
7878 Return the number of bytes placed in the buffer, or zero
7879 upon failure. */
7881 static int
7883 {
7888 }
7891 /* Subroutine of native_encode_expr. Encode the STRING_CST
7892 specified by EXPR into the buffer PTR of length LEN bytes.
7893 Return the number of bytes placed in the buffer, or zero
7894 upon failure. */
7896 static int
7898 {
7901 /* Wide-char strings are encoded in target byte-order so native
7902 encoding them is trivial. */
7917 else
7918 {
7921 {
7924 }
7926 }
7928 }
7931 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
7932 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
7933 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
7934 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
7935 sufficient to encode the entire EXPR, or if OFF is out of bounds.
7936 Otherwise, start at byte offset OFF and encode at most LEN bytes.
7937 Return the number of bytes placed in the buffer, or zero upon failure. */
7939 int
7941 {
7942 /* We don't support starting at negative offset and -1 is special. */
7947 {
7968 }
7969 }
7971 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
7972 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
7973 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
7974 machine modes, we can't just use build_nonstandard_integer_type. */
7976 tree
7978 {
7979 machine_mode mode;
7981 {
7988 {
7992 }
7993 }
7999 {
8007 }
8010 }
8012 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8013 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8014 to be non-NULL and OFF zero), then in addition to filling the
8015 bytes pointed by PTR with the value also clear any bits pointed
8016 by MASK that are known to be initialized, keep them as is for
8017 e.g. uninitialized padding bits or uninitialized fields. */
8019 int
8022 {
8025 /* We don't support starting at negative offset and -1 is special. */
8033 {
8037 mask);
8052 {
8053 HOST_WIDE_INT min_index;
8071 {
8076 {
8079 }
8084 else
8087 {
8095 }
8097 {
8101 }
8104 {
8106 {
8116 }
8118 {
8122 }
8123 }
8127 do
8128 {
8133 {
8135 {
8138 fieldsize);
8141 }
8143 ptr
8146 fieldsize,
8149 mask
8153 else
8154 {
8157 }
8158 }
8161 {
8162 /* Partial overlap. */
8168 {
8172 fieldsize);
8173 }
8174 else
8175 {
8179 }
8182 }
8184 }
8186 }
8188 }
8191 {
8201 {
8207 {
8210 }
8213 {
8222 }
8226 else
8230 {
8231 tree fld;
8233 {
8246 }
8248 {
8252 }
8255 {
8256 cnt--;
8260 }
8261 }
8275 {
8282 else
8288 }
8297 {
8298 /* FIXME: Handle PDP endian. */
8309 {
8312 }
8313 else
8314 {
8322 else
8323 {
8326 }
8327 }
8337 else
8350 /* If the bitfield does not start at byte boundary, handle
8351 the partial byte at the start. */
8354 {
8356 {
8361 {
8364 else
8366 }
8367 }
8368 else
8369 {
8374 {
8377 else
8381 }
8382 }
8383 }
8384 /* If the bitfield does not end at byte boundary, handle
8385 the partial byte at the end. */
8389 {
8391 {
8398 }
8399 else
8400 {
8407 }
8408 }
8412 {
8417 }
8418 else
8419 {
8420 /* Partial overlap. */
8424 {
8427 }
8431 }
8433 }
8438 {
8441 fieldsize,
8445 }
8446 else
8447 {
8448 /* Partial overlap. */
8454 {
8458 fieldsize);
8459 }
8460 else
8461 {
8465 }
8468 }
8469 }
8471 }
8473 }
8474 }
8477 /* Subroutine of native_interpret_expr. Interpret the contents of
8478 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8479 If the buffer cannot be interpreted, return NULL_TREE. */
8481 static tree
8483 {
8493 }
8496 /* Subroutine of native_interpret_expr. Interpret the contents of
8497 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8498 If the buffer cannot be interpreted, return NULL_TREE. */
8500 static tree
8502 {
8505 double_int result;
8506 FIXED_VALUE_TYPE fixed_value;
8516 }
8519 /* Subroutine of native_interpret_expr. Interpret the contents of
8520 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8521 If the buffer cannot be interpreted, return NULL_TREE. */
8523 static tree
8525 {
8529 /* There are always 32 bits in each long, no matter the size of
8530 the hosts long. We handle floating point representations with
8531 up to 192 bits. */
8532 REAL_VALUE_TYPE r;
8542 {
8543 /* Both OFFSET and BYTE index within a long;
8544 bitpos indexes the whole float. */
8547 {
8554 else
8556 }
8557 else
8558 {
8561 {
8562 /* Reverse bytes within each long, or within the entire float
8563 if it's smaller than a long (for HFmode). */
8566 }
8567 }
8571 }
8576 {
8577 /* For floating point values in composite modes, punt if this folding
8578 doesn't preserve bit representation. As the mode doesn't have fixed
8579 precision while GCC pretends it does, there could be valid values that
8580 GCC can't really represent accurately. See PR95450. */
8585 }
8587 }
8590 /* Subroutine of native_interpret_expr. Interpret the contents of
8591 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8592 If the buffer cannot be interpreted, return NULL_TREE. */
8594 static tree
8596 {
8611 }
8613 /* Read a vector of type TYPE from the target memory image given by BYTES,
8614 which contains LEN bytes. The vector is known to be encodable using
8615 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8617 Return the vector on success, otherwise return null. */
8619 static tree
8623 {
8627 {
8628 /* This is the only case in which elements can be smaller than a byte.
8629 Element 0 is always in the lsb of the containing byte. */
8636 {
8643 }
8645 }
8653 {
8659 }
8661 }
8663 /* Subroutine of native_interpret_expr. Interpret the contents of
8664 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8665 If the buffer cannot be interpreted, return NULL_TREE. */
8667 static tree
8669 {
8670 tree etype;
8681 }
8684 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8685 the buffer PTR of length LEN as a constant of type TYPE. For
8686 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8687 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8688 return NULL_TREE. */
8690 tree
8692 {
8694 {
8716 }
8717 }
8719 /* Returns true if we can interpret the contents of a native encoding
8720 as TYPE. */
8722 bool
8724 {
8726 {
8739 }
8740 }
8742 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8743 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8745 tree
8748 {
8751 {
8758 {
8762 }
8767 {
8772 {
8777 }
8781 eltsz);
8785 }
8787 }
8791 {
8799 {
8802 {
8803 poly_int64 bitoffset;
8808 else
8818 }
8819 else
8820 {
8838 HOST_WIDE_INT rpos;
8841 else
8842 {
8845 }
8854 }
8855 }
8858 {
8868 }
8872 {
8877 }
8884 {
8888 /* FIXME: Figure out how to handle PDP endian bitfields. */
8894 else
8898 }
8900 }
8902 }
8904 /* Routines for manipulation of native_encode_expr encoded data if the encoded
8905 or extracted constant positions and/or sizes aren't byte aligned. */
8907 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
8908 bits between adjacent elements. AMNT should be within
8909 [0, BITS_PER_UNIT).
8910 Example, AMNT = 2:
8911 00011111|11100000 << 2 = 01111111|10000000
8912 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
8914 void
8917 {
8926 {
8932 {
8935 }
8936 }
8937 }
8939 /* Like shift_bytes_in_array_left but for big-endian.
8940 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
8941 bits between adjacent elements. AMNT should be within
8942 [0, BITS_PER_UNIT).
8943 Example, AMNT = 2:
8944 00011111|11100000 >> 2 = 00000111|11111000
8945 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
8947 void
8950 {
8958 {
8965 }
8966 }
8968 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
8969 directly on the VECTOR_CST encoding, in a way that works for variable-
8970 length vectors. Return the resulting VECTOR_CST on success or null
8971 on failure. */
8973 static tree
8975 {
8987 /* We can only preserve the semantics of a stepped pattern if the new
8988 vector element is an integer of the same size. */
8993 /* The number of bits needed to encode one element from every pattern
8994 of the original vector. */
8995 unsigned int expr_sequence_bits
8998 /* The number of bits needed to encode one element from every pattern
8999 of the result. */
9000 unsigned int type_sequence_bits
9003 /* Don't try to read more bytes than are available, which can happen
9004 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9005 The general VIEW_CONVERT handling can cope with that case, so there's
9006 no point complicating things here. */
9009 BITS_PER_UNIT);
9014 /* Get enough bytes of EXPR to form the new encoding. */
9022 /* Reencode the bytes as TYPE. */
9026 }
9028 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9029 TYPE at compile-time. If we're unable to perform the conversion
9030 return NULL_TREE. */
9032 static tree
9034 {
9035 /* We support up to 512-bit values (for V8DFmode). */
9039 /* Check that the host and target are sane. */
9052 }
9054 /* Build an expression for the address of T. Folds away INDIRECT_REF
9055 to avoid confusing the gimplify process. */
9057 tree
9059 {
9060 /* The size of the object is not relevant when talking about its address. */
9065 {
9070 }
9073 {
9078 }
9085 {
9090 }
9091 else
9095 }
9097 /* Build an expression for the address of T. */
9099 tree
9101 {
9105 }
9107 /* Fold a unary expression of code CODE and type TYPE with operand
9108 OP0. Return the folded expression if folding is successful.
9109 Otherwise, return NULL_TREE. */
9111 tree
9113 {
9114 tree tem;
9115 tree arg0;
9123 {
9126 {
9127 /* Don't use STRIP_NOPS, because signedness of argument type
9128 matters. */
9130 }
9131 else
9132 {
9133 /* Strip any conversions that don't change the mode. This
9134 is safe for every expression, except for a comparison
9135 expression because its signedness is derived from its
9136 operands.
9138 Note that this is done as an internal manipulation within
9139 the constant folder, in order to find the simplest
9140 representation of the arguments so that their form can be
9141 studied. In any cases, the appropriate type conversions
9142 should be put back in the tree that will get out of the
9143 constant folder. */
9145 }
9148 {
9151 {
9155 }
9156 }
9157 }
9164 {
9171 {
9185 /* If this was a conversion, and all we did was to move into
9186 inside the COND_EXPR, bring it back out. But leave it if
9187 it is a conversion from integer to integer and the
9188 result precision is no wider than a word since such a
9189 conversion is cheap and may be optimized away by combine,
9190 while it couldn't if it were outside the COND_EXPR. Then return
9191 so we don't get into an infinite recursion loop taking the
9192 conversion out and then back in. */
9204 && (INTEGRAL_TYPE_P
9217 }
9218 }
9221 {
9227 CASE_CONVERT:
9231 {
9232 /* If we have (type) (a CMP b) and type is an integral type, return
9233 new expression involving the new type. Canonicalize
9234 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9235 non-integral type.
9236 Do not fold the result as that would not simplify further, also
9237 folding again results in recursions. */
9247 }
9249 /* Handle (T *)&A.B.C for A being of type T and B and C
9250 living at offset zero. This occurs frequently in
9251 C++ upcasting and then accessing the base. */
9255 {
9257 tree offset;
9258 machine_mode mode;
9260 tree base
9264 /* If the reference was to a (constant) zero offset, we can use
9265 the address of the base if it has the same base type
9266 as the result type and the pointer type is unqualified. */
9274 }
9278 /* Detect assigning a bitfield. */
9280 && DECL_BIT_FIELD
9282 {
9283 /* Don't leave an assignment inside a conversion
9284 unless assigning a bitfield. */
9286 /* First do the assignment, then return converted constant. */
9291 }
9293 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9294 constants (if x has signed type, the sign bit cannot be set
9295 in c). This folds extension into the BIT_AND_EXPR.
9296 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9297 very likely don't have maximal range for their precision and this
9298 transformation effectively doesn't preserve non-maximal ranges. */
9302 {
9313 <= HOST_BITS_PER_WIDE_INT
9315 {
9319 cst &= HOST_WIDE_INT_M1U
9323 && !flag_syntax_only
9326 {
9330 }
9331 }
9333 {
9338 }
9339 }
9341 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9342 cast (T1)X will fold away. We assume that this happens when X itself
9343 is a cast. */
9347 {
9351 return fold_build_pointer_plus_loc
9353 }
9355 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9356 of the same precision, and X is an integer type not narrower than
9357 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9363 {
9369 }
9371 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9372 type of X and Y (integer types only). */
9377 {
9378 /* Be careful not to introduce new overflows. */
9379 tree mult_type;
9382 else
9386 {
9393 }
9394 }
9400 {
9407 }
9418 /* Convert fabs((double)float) into (double)fabsf(float). */
9421 {
9427 targ0));
9428 }
9432 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9451 /* Note that the operand of this must be an int
9452 and its values must be 0 or 1.
9453 ("true" is a fixed value perhaps depending on the language,
9454 but we don't handle values other than 1 correctly yet.) */
9461 /* Fold *&X to X if X is an lvalue. */
9463 {
9470 }
9476 }
9479 /* If the operation was a conversion do _not_ mark a resulting constant
9480 with TREE_OVERFLOW if the original constant was not. These conversions
9481 have implementation defined behavior and retaining the TREE_OVERFLOW
9482 flag here would confuse later passes such as VRP. */
9483 tree
9486 {
9495 }
9497 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9498 operands OP0 and OP1. LOC is the location of the resulting expression.
9499 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9500 Return the folded expression if folding is successful. Otherwise,
9501 return NULL_TREE. */
9502 static tree
9505 {
9506 tree tem;
9508 /* We only do these simplifications if we are optimizing. */
9512 /* Check for things like (A || B) && (A || C). We can convert this
9513 to A || (B && C). Note that either operator can be any of the four
9514 truth and/or operations and the transformation will still be
9515 valid. Also note that we only care about order for the
9516 ANDIF and ORIF operators. If B contains side effects, this
9517 might change the truth-value of A. */
9524 {
9544 /* This case if tricky because we must either have commutative
9545 operators or else A10 must not have side-effects. */
9551 a01);
9552 }
9554 /* See if we can build a range comparison. */
9560 {
9564 }
9568 {
9572 }
9574 /* Check for the possibility of merging component references. If our
9575 lhs is another similar operation, try to merge its rhs with our
9576 rhs. Then try to merge our lhs and rhs. */
9587 logical_op_non_short_circuit
9590 && !flag_sanitize_coverage
9595 {
9602 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9603 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9604 We don't want to pack more than two leafs to a non-IF AND/OR
9605 expression.
9606 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9607 equal to IF-CODE, then we don't want to add right-hand operand.
9608 If the inner right-hand side of left-hand operand has
9609 side-effects, or isn't simple, then we can't add to it,
9610 as otherwise we might destroy if-sequence. */
9613 /* Needed for sequence points to handle trappings, and
9614 side-effects. */
9616 {
9618 arg1);
9620 tem);
9621 }
9622 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9623 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9626 /* Needed for sequence points to handle trappings, and
9627 side-effects. */
9629 {
9634 }
9635 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9636 into (A OR B).
9637 For sequence point consistancy, we need to check for trapping,
9638 and side-effects. */
9642 }
9645 }
9647 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9648 by changing CODE to reduce the magnitude of constants involved in
9649 ARG0 of the comparison.
9650 Returns a canonicalized comparison tree if a simplification was
9651 possible, otherwise returns NULL_TREE.
9652 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9653 valid if signed overflow is undefined. */
9655 static tree
9659 {
9664 /* Match A +- CST code arg1. We can change this only if overflow
9665 is undefined. */
9668 /* In principle pointers also have undefined overflow behavior,
9669 but that causes problems elsewhere. */
9676 /* Identify the constant in arg0 and its sign. */
9680 /* Overflowed constants and zero will cause problems. */
9685 /* See if we can reduce the magnitude of the constant in
9686 arg0 by changing the comparison code. */
9687 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9691 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9695 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9699 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9703 else
9707 /* Now build the constant reduced in magnitude. But not if that
9708 would produce one outside of its types range. */
9724 }
9726 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9727 overflow further. Try to decrease the magnitude of constants involved
9728 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9729 and put sole constants at the second argument position.
9730 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9732 static tree
9735 {
9736 tree t;
9741 /* Try canonicalization by simplifying arg0. */
9746 {
9750 }
9752 /* Try canonicalization by simplifying arg1 using the swapped
9753 comparison. */
9761 }
9763 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9764 space. This is used to avoid issuing overflow warnings for
9765 expressions like &p->x which cannot wrap. */
9767 static bool
9769 {
9776 poly_wide_int wi_offset;
9782 else
9787 precision);
9802 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9803 array. */
9812 }
9814 /* Return a positive integer when the symbol DECL is known to have
9815 a nonzero address, zero when it's known not to (e.g., it's a weak
9816 symbol), and a negative integer when the symbol is not yet in the
9817 symbol table and so whether or not its address is zero is unknown.
9818 For function local objects always return positive integer. */
9819 static int
9821 {
9826 /* Function local objects are never NULL. */
9834 }
9836 /* Subroutine of fold_binary. This routine performs all of the
9837 transformations that are common to the equality/inequality
9838 operators (EQ_EXPR and NE_EXPR) and the ordering operators
9839 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
9840 fold_binary should call fold_binary. Fold a comparison with
9841 tree code CODE and type TYPE with operands OP0 and OP1. Return
9842 the folded comparison or NULL_TREE. */
9844 static tree
9847 {
9857 /* For comparisons of pointers we can decompose it to a compile time
9858 comparison of the base objects and the offsets into the object.
9859 This requires at least one operand being an ADDR_EXPR or a
9860 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
9866 {
9869 machine_mode mode;
9873 /* Get base and offset for the access. Strip ADDR_EXPR for
9874 get_inner_reference, but put it back by stripping INDIRECT_REF
9875 off the base object if possible. indirect_baseN will be true
9876 if baseN is not an address but refers to the object itself. */
9879 {
9880 base0
9886 else
9888 }
9890 {
9894 {
9895 base0
9901 else
9903 }
9906 else
9910 {
9917 }
9918 }
9922 {
9923 base1
9929 else
9931 }
9933 {
9937 {
9938 base1
9944 else
9946 }
9949 else
9953 {
9960 }
9961 }
9963 /* If we have equivalent bases we might be able to simplify. */
9967 {
9968 /* We can fold this expression to a constant if the non-constant
9969 offset parts are equal. */
9973 && (equality_code
9974 || (indirect_base0
9977 {
9983 "occur when comparing P +- C1 with "
9985 WARN_STRICT_OVERFLOW_CONDITIONAL);
9988 {
10026 }
10027 }
10028 /* We can simplify the comparison to a comparison of the variable
10029 offset parts if the constant offset parts are equal.
10030 Be careful to use signed sizetype here because otherwise we
10031 mess with array offsets in the wrong way. This is possible
10032 because pointer arithmetic is restricted to retain within an
10033 object and overflow on pointer differences is undefined as of
10034 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10036 && (equality_code
10037 || (indirect_base0
10040 {
10041 /* By converting to signed sizetype we cover middle-end pointer
10042 arithmetic which operates on unsigned pointer types of size
10043 type size and ARRAY_REF offsets which are properly sign or
10044 zero extended from their type in case it is narrower than
10045 sizetype. */
10048 else
10052 else
10059 "occur when comparing P +- C1 with "
10061 WARN_STRICT_OVERFLOW_COMPARISON);
10064 }
10065 }
10066 /* For equal offsets we can simplify to a comparison of the
10067 base addresses. */
10069 && (indirect_base0
10071 && (indirect_base1
10076 {
10082 }
10083 /* Comparison between an ordinary (non-weak) symbol and a null
10084 pointer can be eliminated since such symbols must have a non
10085 null address. In C, relational expressions between pointers
10086 to objects and null pointers are undefined. The results
10087 below follow the C++ rules with the additional property that
10088 every object pointer compares greater than a null pointer.
10089 */
10092 /* Avoid folding references to struct members at offset 0 to
10093 prevent tests like '&ptr->firstmember == 0' from getting
10094 eliminated. When ptr is null, although the -> expression
10095 is strictly speaking invalid, GCC retains it as a matter
10096 of QoI. See PR c/44555. */
10099 && indirect_base0
10100 /* The caller guarantees that when one of the arguments is
10101 constant (i.e., null in this case) it is second. */
10103 {
10105 {
10116 }
10117 }
10118 }
10120 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10121 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10122 the resulting offset is smaller in absolute value than the
10123 original one and has the same sign. */
10132 {
10137 tree cst;
10139 "occur when combining constants around "
10142 /* Put the constant on the side where it doesn't overflow and is
10143 of lower absolute value and of same sign than before. */
10150 {
10153 variable1,
10157 }
10165 {
10171 variable2);
10172 }
10173 }
10179 /* If we are comparing an expression that just has comparisons
10180 of two integer values, arithmetic expressions of those comparisons,
10181 and constants, we can simplify it. There are only three cases
10182 to check: the two values can either be equal, the first can be
10183 greater, or the second can be greater. Fold the expression for
10184 those three values. Since each value must be 0 or 1, we have
10185 eight possibilities, each of which corresponds to the constant 0
10186 or 1 or one of the six possible comparisons.
10188 This handles common cases like (a > b) == 0 but also handles
10189 expressions like ((x > y) - (y > x)) > 0, which supposedly
10190 occur in macroized code. */
10193 {
10197 /* Don't handle degenerate cases here; they should already
10198 have been handled anyway. */
10207 {
10211 /* We can't just pass T to eval_subst in case cval1 or cval2
10212 was the same as ARG1. */
10214 tree high_result
10218 arg1);
10219 tree equal_result
10223 arg1);
10224 tree low_result
10228 arg1);
10230 /* All three of these results should be 0 or 1. Confirm they are.
10231 Then use those values to select the proper code to use. */
10236 {
10237 /* Make a 3-bit mask with the high-order bit being the
10238 value for `>', the next for '=', and the low for '<'. */
10242 {
10244 /* Always false. */
10265 /* Always true. */
10267 }
10270 }
10271 }
10272 }
10275 }
10278 /* Subroutine of fold_binary. Optimize complex multiplications of the
10279 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10280 argument EXPR represents the expression "z" of type TYPE. */
10282 static tree
10284 {
10289 {
10292 }
10294 {
10297 }
10298 else
10299 {
10303 }
10312 }
10315 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10316 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10317 true if successful. */
10319 static bool
10321 {
10326 {
10329 }
10331 {
10337 else
10339 }
10340 else
10346 }
10348 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10349 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10350 NULL_TREE otherwise. */
10352 tree
10354 {
10375 {
10376 HOST_WIDE_INT index;
10382 }
10385 {
10391 }
10392 else
10394 }
10396 /* Try to fold a pointer difference of type TYPE two address expressions of
10397 array references AREF0 and AREF1 using location LOC. Return a
10398 simplified expression for the difference or NULL_TREE. */
10400 static tree
10404 {
10409 /* If the bases are array references as well, recurse. If the bases
10410 are pointer indirections compute the difference of the pointers.
10411 If the bases are equal, we are set. */
10414 && (base_offset
10416 use_pointer_diff)))
10419 && (base_offset
10420 = use_pointer_diff
10430 {
10436 base_offset,
10439 }
10441 }
10443 /* If the real or vector real constant CST of type TYPE has an exact
10444 inverse, return it, else return NULL. */
10446 tree
10448 {
10449 REAL_VALUE_TYPE r;
10450 tree unit_type;
10451 machine_mode mode;
10454 {
10464 {
10468 tree_vector_builder elts;
10473 {
10478 }
10481 }
10485 }
10486 }
10488 /* Mask out the tz least significant bits of X of type TYPE where
10489 tz is the number of trailing zeroes in Y. */
10490 static wide_int
10492 {
10497 }
10499 /* Return true when T is an address and is known to be nonzero.
10500 For floating point we further ensure that T is not denormal.
10501 Similar logic is present in nonzero_address in rtlanal.h.
10503 If the return value is based on the assumption that signed overflow
10504 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10505 change *STRICT_OVERFLOW_P. */
10507 static bool
10509 {
10513 /* Doing something useful for floating point would need more work. */
10519 {
10522 strict_overflow_p);
10528 strict_overflow_p);
10536 }
10539 {
10542 strict_overflow_p);
10550 strict_overflow_p);
10565 strict_overflow_p);
10569 strict_overflow_p);
10572 {
10584 }
10588 }
10590 }
10592 /* Return true when T is an address and is known to be nonzero.
10593 Handle warnings about undefined signed overflow. */
10595 bool
10597 {
10604 "determining that expression is always "
10606 WARN_STRICT_OVERFLOW_MISC);
10608 }
10610 /* Return true if T is known not to be equal to an integer W. */
10612 bool
10614 {
10615 value_range vr;
10617 {
10628 /* If T has some known zero bits and W has any of those bits set,
10629 then T is known not to be equal to W. */
10637 }
10638 }
10640 /* Fold a binary expression of code CODE and type TYPE with operands
10641 OP0 and OP1. LOC is the location of the resulting expression.
10642 Return the folded expression if folding is successful. Otherwise,
10643 return NULL_TREE. */
10645 tree
10648 {
10663 /* Strip any conversions that don't change the mode. This is
10664 safe for every expression, except for a comparison expression
10665 because its signedness is derived from its operands. So, in
10666 the latter case, only strip conversions that don't change the
10667 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10668 preserved.
10670 Note that this is done as an internal manipulation within the
10671 constant folder, in order to find the simplest representation
10672 of the arguments so that their form can be studied. In any
10673 cases, the appropriate type conversions should be put back in
10674 the tree that will get out of the constant folder. */
10677 {
10680 }
10681 else
10682 {
10685 }
10687 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10688 constant but we can't do arithmetic on them. */
10690 {
10693 {
10697 }
10698 }
10700 /* If this is a commutative operation, and ARG0 is a constant, move it
10701 to ARG1 to reduce the number of tests below. */
10706 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10707 to ARG1 to reduce the number of tests below. */
10716 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10718 First check for cases where an arithmetic operation is applied to a
10719 compound, conditional, or comparison operation. Push the arithmetic
10720 operation inside the compound or conditional to see if any folding
10721 can then be done. Convert comparison to conditional for this purpose.
10722 The also optimizes non-constant cases that used to be done in
10723 expand_expr.
10725 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10726 one of the operands is a comparison and the other is a comparison, a
10727 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10728 code below would make the expression more complex. Change it to a
10729 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10730 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10743 {
10747 boolean_type_node,
10755 }
10759 {
10761 {
10766 tem);
10767 }
10769 {
10774 tem);
10775 }
10780 {
10786 }
10791 {
10797 }
10798 }
10801 {
10803 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10806 {
10812 }
10814 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10817 {
10818 tree base;
10819 poly_int64 coffset;
10828 }
10833 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
10839 arg1),
10841 arg0)));
10847 {
10848 /* X + (X / CST) * -CST is X % CST. */
10853 {
10862 cst0));
10863 }
10864 }
10866 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
10867 one. Make sure the type is not saturating and has the signedness of
10868 the stripped operands, as fold_plusminus_mult_expr will re-associate.
10869 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
10876 {
10880 }
10883 {
10884 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
10885 (plus (plus (mult) (mult)) (foo)) so that we can
10886 take advantage of the factoring cases below. */
10895 {
10901 else
10914 parg0),
10916 marg)),
10920 return
10926 parg1)));
10927 }
10928 }
10929 else
10930 {
10931 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
10932 to __complex__ ( x, y ). This is not the same for SNaNs or
10933 if signed zeros are involved. */
10937 {
10944 {
10948 {
10954 }
10956 {
10962 }
10963 }
10964 }
10966 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
10967 We associate floats only if the user has specified
10968 -fassociative-math. */
10972 {
10977 {
10978 tree tree0;
10981 }
10982 }
10983 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
10984 We associate floats only if the user has specified
10985 -fassociative-math. */
10989 {
10994 {
10995 tree tree0;
10998 }
10999 }
11000 }
11002 bit_rotate:
11003 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11004 is a rotate of A by C1 bits. */
11005 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11006 is a rotate of A by B bits.
11007 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11008 though in this case CODE must be | and not + or ^, otherwise
11009 it doesn't return A when B is 0. */
11010 {
11012 tree rtype;
11021 /* Only create rotates in complete modes. Other cases are not
11022 expanded properly. */
11025 {
11038 {
11043 }
11048 {
11051 code0 == LSHIFT_EXPR
11054 }
11056 {
11066 {
11070 orig_tree01);
11072 }
11073 }
11077 {
11088 {
11092 orig_tree01);
11094 }
11095 }
11096 }
11097 }
11099 associate:
11100 /* In most languages, can't associate operations on floats through
11101 parentheses. Rather than remember where the parentheses were, we
11102 don't associate floats at all, unless the user has specified
11103 -fassociative-math.
11104 And, we need to make sure type is not saturating. */
11108 {
11114 /* Split both trees into variables, constants, and literals. Then
11115 associate each group together, the constants with literals,
11116 then the result with variables. This increases the chances of
11117 literals being recombined later and of generating relocatable
11118 expressions for the sum of a constant and literal. */
11126 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11130 /* With undefined overflow prefer doing association in a type
11131 which wraps on overflow, if that is one of the operand types. */
11134 {
11142 }
11144 /* With undefined overflow we can only associate constants with one
11145 variable, and constants whose association doesn't overflow. */
11148 {
11150 {
11151 /* ??? If split_tree would handle NEGATE_EXPR we could
11152 simply reject these cases and the allowed cases would
11153 be the var0/minus_var1 ones. */
11159 {
11162 }
11169 {
11172 }
11178 /* The only case we can still associate with two variables
11179 is if they cancel out. */
11183 }
11189 }
11191 /* Only do something if we found more than two objects. Otherwise,
11192 nothing has changed and we risk infinite recursion. */
11200 {
11212 {
11216 }
11218 {
11222 }
11224 /* Preserve the MINUS_EXPR if the negative part of the literal is
11225 greater than the positive part. Otherwise, the multiplicative
11226 folding code (i.e extract_muldiv) may be fooled in case
11227 unsigned constants are subtracted, like in the following
11228 example: ((X*2 + 4) - 8U)/2. */
11230 {
11234 /* But avoid ending up with only negated parts. */
11236 {
11240 }
11241 else
11242 {
11246 }
11247 }
11249 /* Don't introduce overflows through reassociation. */
11254 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11261 /* Eliminate minus_con0. */
11263 {
11270 else
11273 }
11275 /* Eliminate minus_var0. */
11277 {
11281 else
11284 }
11286 return
11289 }
11290 }
11296 /* Fold &a[i] - &a[j] to i-j. */
11301 {
11305 code
11309 }
11311 /* Further transformations are not for pointers. */
11315 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11318 /* If arg0 is e.g. unsigned int and type is int, then this could
11319 introduce UB, because if A is INT_MIN at runtime, the original
11320 expression can be well defined while the latter is not.
11321 See PR83269. */
11330 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11331 __complex__ ( x, -y ). This is not the same for SNaNs or if
11332 signed zeros are involved. */
11336 {
11343 {
11347 {
11349 arg1r ? arg1r
11354 }
11356 {
11360 arg1i ? arg1i
11363 }
11364 }
11365 }
11367 /* A - B -> A + (-B) if B is easily negatable. */
11371 /* Avoid this transformation if B is a positive REAL_CST. */
11379 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11380 one. Make sure the type is not saturating and has the signedness of
11381 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11382 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11389 {
11393 }
11399 {
11400 /* Transform x * -C into -x * C if x is easily negatable. */
11415 {
11418 "occur when simplifying "
11420 WARN_STRICT_OVERFLOW_MISC);
11422 }
11424 /* Optimize z * conj(z) for integer complex numbers. */
11431 }
11432 else
11433 {
11434 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11435 This is not the same for NaNs or if signed zeros are
11436 involved. */
11442 {
11445 return
11451 return
11456 }
11458 /* Optimize z * conj(z) for floating point complex numbers.
11459 Guarded by flag_unsafe_math_optimizations as non-finite
11460 imaginary components don't produce scalar results. */
11469 }
11473 /* Canonicalize (X & C1) | C2. */
11477 {
11482 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11490 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11492 {
11495 }
11497 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11498 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11499 mode which allows further optimizations. */
11504 {
11509 {
11512 }
11513 }
11516 {
11521 }
11522 }
11524 /* See if this can be simplified into a rotate first. If that
11525 is unsuccessful continue in the association code. */
11529 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11537 /* See if this can be simplified into a rotate first. If that
11538 is unsuccessful continue in the association code. */
11542 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11547 {
11548 tree tem2;
11555 }
11556 /* Fold ~X & 1 as (X & 1) == 0. */
11560 {
11561 tree tem2;
11568 }
11569 /* Fold !X & 1 as X == 0. */
11572 {
11576 }
11578 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11579 multiple of 1 << CST. */
11581 {
11588 }
11590 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11591 bits from CST2. */
11595 {
11597 wide_int masked
11604 {
11605 /* Avoid the transform if arg1 is a mask of some
11606 mode which allows further optimizations. */
11613 }
11614 }
11616 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11619 {
11624 return
11626 }
11631 /* Don't touch a floating-point divide by zero unless the mode
11632 of the constant can represent infinity. */
11638 /* (-A) / (-B) -> A / B */
11650 /* Fall through */
11653 /* Simplify A / (B << N) where A and B are positive and B is
11654 a power of 2, to A >> (N + log2(B)). */
11659 {
11662 {
11670 WARN_STRICT_OVERFLOW_MISC);
11676 }
11677 }
11679 /* Fall through */
11687 /* Convert -A / -B to A / B when the type is signed and overflow is
11688 undefined. */
11692 {
11695 "when distributing negation across "
11697 WARN_STRICT_OVERFLOW_MISC);
11702 }
11706 {
11709 "when distributing negation across "
11711 WARN_STRICT_OVERFLOW_MISC);
11716 }
11718 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11719 operation, EXACT_DIV_EXPR.
11721 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11722 At one time others generated faster code, it's not clear if they do
11723 after the last round to changes to the DIV code in expmed.c. */
11734 {
11738 WARN_STRICT_OVERFLOW_MISC);
11740 }
11752 {
11756 WARN_STRICT_OVERFLOW_MISC);
11758 }
11766 /* Since negative shift count is not well-defined,
11767 don't try to compute it in the compiler. */
11773 /* If we have a rotate of a bit operation with the rotate count and
11774 the second operand of the bit operation both constant,
11775 permute the two operations. */
11781 {
11789 }
11791 /* Two consecutive rotates adding up to the some integer
11792 multiple of the precision of the type can be ignored. */
11808 /* Note that the operands of this must be ints
11809 and their values must be 0 or 1.
11810 ("true" is a fixed value perhaps depending on the language.) */
11811 /* If first arg is constant zero, return it. */
11814 /* FALLTHRU */
11816 /* If either arg is constant true, drop it. */
11820 /* Preserve sequence points. */
11823 /* If second arg is constant zero, result is zero, but first arg
11824 must be evaluated. */
11827 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
11828 case will be handled here. */
11832 /* !X && X is always false. */
11836 /* X && !X is always false. */
11841 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
11842 means A >= Y && A != MAX, but in this case we know that
11843 A < X <= MAX. */
11847 {
11855 }
11864 /* Note that the operands of this must be ints
11865 and their values must be 0 or true.
11866 ("true" is a fixed value perhaps depending on the language.) */
11867 /* If first arg is constant true, return it. */
11870 /* FALLTHRU */
11872 /* If either arg is constant zero, drop it. */
11876 /* Preserve sequence points. */
11879 /* If second arg is constant true, result is true, but we must
11880 evaluate first arg. */
11883 /* Likewise for first arg, but note this only occurs here for
11884 TRUTH_OR_EXPR. */
11888 /* !X || X is always true. */
11892 /* X || !X is always true. */
11897 /* (X && !Y) || (!X && Y) is X ^ Y */
11900 {
11917 }
11926 /* If the second arg is constant zero, drop it. */
11929 /* If the second arg is constant true, this is a logical inversion. */
11931 {
11934 }
11935 /* Identical arguments cancel to zero. */
11939 /* !X ^ X is always true. */
11944 /* X ^ !X is always true. */
11960 /* bool_var != 1 becomes !bool_var. */
11967 /* bool_var == 0 becomes !bool_var. */
11974 /* !exp != 0 becomes !exp */
11979 /* If this is an EQ or NE comparison with zero and ARG0 is
11980 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
11981 two operations, but the latter can be done in one less insn
11982 on machines that have only two-operand insns or on which a
11983 constant cannot be the first operand. */
11986 {
11991 {
11998 arg1);
11999 }
12002 {
12009 arg1);
12010 }
12011 }
12013 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
12014 C1 is a valid shift constant, and C2 is a power of two, i.e.
12015 a single bit. */
12019 {
12024 {
12029 /* Check for a valid shift count. */
12031 {
12035 /* If (C2 << C1) doesn't overflow, then
12036 ((X >> C1) & C2) != 0 can be rewritten as
12037 (X & (C2 << C1)) != 0. */
12039 {
12046 }
12047 /* Otherwise, for signed (arithmetic) shifts,
12048 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
12049 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
12055 /* Otherwise, of unsigned (logical) shifts,
12056 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
12057 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
12058 else
12062 arg000);
12063 }
12064 }
12065 }
12067 /* If this is a comparison of a field, we may be able to simplify it. */
12070 /* Handle the constant case even without -O
12071 to make sure the warnings are given. */
12073 {
12077 }
12079 /* Optimize comparisons of strlen vs zero to a compare of the
12080 first character of the string vs zero. To wit,
12081 strlen(ptr) == 0 => *ptr == 0
12082 strlen(ptr) != 0 => *ptr != 0
12083 Other cases should reduce to one of these two (or a constant)
12084 due to the return value of strlen being unsigned. */
12086 {
12094 {
12095 tree ptrtype
12097 TYPE_QUAL_CONST));
12103 }
12104 }
12106 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12107 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12111 {
12116 {
12118 {
12121 }
12124 }
12125 }
12127 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12128 (X & C) == 0 when C is a single bit. */
12133 {
12140 arg1));
12141 }
12143 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12144 constant C is a power of two, i.e. a single bit. */
12151 {
12155 }
12157 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12158 when is C is a power of two, i.e. a single bit. */
12165 {
12171 }
12175 {
12178 }
12182 {
12189 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12190 operand_equal_p guarantees no side-effects so we don't need
12191 to use omit_one_operand on Z. */
12195 arg10));
12199 arg11));
12203 arg10));
12207 arg11));
12209 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12212 {
12218 }
12219 }
12221 /* Attempt to simplify equality/inequality comparisons of complex
12222 values. Only lower the comparison if the result is known or
12223 can be simplified to a single scalar comparison. */
12228 {
12233 {
12236 }
12237 else
12238 {
12241 }
12244 {
12247 }
12248 else
12249 {
12252 }
12256 {
12258 {
12263 }
12264 else
12265 {
12270 }
12271 }
12275 {
12277 {
12282 }
12283 else
12284 {
12289 }
12290 }
12291 }
12303 /* Transform comparisons of the form X +- C CMP X. */
12308 {
12313 /* (X - c) > X becomes false. */
12319 /* Likewise (X + c) < X becomes false. */
12325 /* Convert (X - c) <= X to true. */
12332 /* Convert (X + c) >= X to true. */
12338 }
12340 /* If we are comparing an ABS_EXPR with a constant, we can
12341 convert all the cases into explicit comparisons, but they may
12342 well not be faster than doing the ABS and one comparison.
12343 But ABS (X) <= C is a range comparison, which becomes a subtraction
12344 and a comparison, and is probably faster. */
12358 /* Convert ABS_EXPR<x> >= 0 to true. */
12365 {
12368 "when simplifying comparison of "
12370 WARN_STRICT_OVERFLOW_CONDITIONAL);
12373 arg0);
12374 }
12376 /* Convert ABS_EXPR<x> < 0 to false. */
12381 {
12384 "when simplifying comparison of "
12386 WARN_STRICT_OVERFLOW_CONDITIONAL);
12389 arg0);
12390 }
12392 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12393 and similarly for >= into !=. */
12403 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12404 otherwise Y might be >= # of bits in X's type and thus e.g.
12405 (unsigned char) (1 << Y) for Y 15 might be 0.
12406 If the cast is widening, then 1 << Y should have unsigned type,
12407 otherwise if Y is number of bits in the signed shift type minus 1,
12408 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12409 31 might be 0xffffffff80000000. */
12420 {
12426 }
12438 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12439 {
12451 }
12456 /* When pedantic, a compound expression can be neither an lvalue
12457 nor an integer constant expression. */
12460 /* Don't let (0, 0) be null pointer constant. */
12466 /* An ASSERT_EXPR should never be passed to fold_binary. */
12472 }
12474 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12475 ((A & N) + B) & M -> (A + B) & M
12476 Similarly if (N & M) == 0,
12477 ((A | N) + B) & M -> (A + B) & M
12478 and for - instead of + (or unary - instead of +)
12479 and/or ^ instead of |.
12480 If B is constant and (B & M) == 0, fold into A & M.
12482 This function is a helper for match.pd patterns. Return non-NULL
12483 type in which the simplified operation should be performed only
12484 if any optimization is possible.
12486 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12487 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12488 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12489 +/-. */
12490 tree
12495 {
12510 wide_int cst0;
12512 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12513 arg1 (M) is == (1LL << cst) - 1.
12514 Store C into PMOP[0] and D into PMOP[1]. */
12521 {
12528 {
12531 }
12534 /* If C or D is of the form (A & N) where
12535 (N & M) == M, or of the form (A | N) or
12536 (A ^ N) where (N & M) == 0, replace it with A. */
12542 /* If C or D is a N where (N & M) == 0, it can be
12543 omitted (replaced with 0). */
12548 /* Similarly, with C - N where (-N & M) == 0. */
12556 }
12558 /* Only build anything new if we optimized one or both arguments above. */
12564 else
12566 }
12568 /* Used by contains_label_[p1]. */
12570 struct contains_label_data
12571 {
12574 };
12576 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12577 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12578 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12580 static tree
12582 {
12585 {
12596 {
12604 }
12613 }
12614 }
12616 /* Return whether the sub-tree ST contains a label which is accessible from
12617 outside the sub-tree. */
12619 static bool
12621 {
12625 }
12627 /* Fold a ternary expression of code CODE and type TYPE with operands
12628 OP0, OP1, and OP2. Return the folded expression if folding is
12629 successful. Otherwise, return NULL_TREE. */
12631 tree
12634 {
12635 tree tem;
12642 /* If this is a commutative operation, and OP0 is a constant, move it
12643 to OP1 to reduce the number of tests below. */
12652 /* Strip any conversions that don't change the mode. This is safe
12653 for every expression, except for a comparison expression because
12654 its signedness is derived from its operands. So, in the latter
12655 case, only strip conversions that don't change the signedness.
12657 Note that this is done as an internal manipulation within the
12658 constant folder, in order to find the simplest representation of
12659 the arguments so that their form can be studied. In any cases,
12660 the appropriate type conversions should be put back in the tree
12661 that will get out of the constant folder. */
12663 {
12666 }
12669 {
12672 }
12675 {
12678 }
12681 {
12685 {
12691 }
12696 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12697 so all simple results must be passed through pedantic_non_lvalue. */
12699 {
12702 /* Only optimize constant conditions when the selected branch
12703 has the same type as the COND_EXPR. This avoids optimizing
12704 away "c ? x : throw", where the throw has a void type.
12705 Avoid throwing away that operand which contains label. */
12712 }
12714 {
12721 {
12724 {
12732 }
12737 }
12738 }
12740 /* If we have A op B ? A : C, we may be able to convert this to a
12741 simpler expression, depending on the operation and the values
12742 of B and C. Signed zeros prevent all of these transformations,
12743 for reasons given above each one.
12745 Also try swapping the arguments and inverting the conditional. */
12749 {
12753 }
12758 {
12762 {
12766 }
12767 }
12769 /* If the second operand is simpler than the third, swap them
12770 since that produces better jump optimization results. */
12773 {
12775 /* See if this can be inverted. If it can't, possibly because
12776 it was a floating-point inequality comparison, don't do
12777 anything. */
12781 }
12783 /* Convert A ? 1 : 0 to simply A. */
12788 /* If we try to convert OP0 to our type, the
12789 call to fold will try to move the conversion inside
12790 a COND, which will recurse. In that case, the COND_EXPR
12791 is probably the best choice, so leave it alone. */
12795 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12796 over COND_EXPR in cases such as floating point comparisons. */
12805 arg0)));
12807 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12812 {
12813 /* sign_bit_p looks through both zero and sign extensions,
12814 but for this optimization only sign extensions are
12815 usable. */
12818 {
12821 {
12824 }
12826 }
12827 /* sign_bit_p only checks ARG1 bits within A's precision.
12828 If <sign bit of A> has wider type than A, bits outside
12829 of A's precision in <sign bit of A> need to be checked.
12830 If they are all 0, this optimization needs to be done
12831 in unsigned A's type, if they are all 1 in signed A's type,
12832 otherwise this can't be done. */
12838 {
12840 tree tem_type;
12853 {
12856 }
12858 {
12861 }
12862 else
12864 }
12867 return
12873 arg1)));
12874 }
12876 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
12877 already handled above. */
12882 {
12892 op1);
12893 }
12895 /* A & N ? N : 0 is simply A & N if N is a power of two. This
12896 is probably obsolete because the first operand should be a
12897 truth value (that's why we have the two cases above), but let's
12898 leave it in until we can confirm this for all front-ends. */
12906 /* operand_equal_p compares just value, not precision, so e.g.
12907 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
12908 second operand 32-bit -128, which is not a power of two (or vice
12909 versa. */
12916 /* Disable the transformations below for vectors, since
12917 fold_binary_op_with_conditional_arg may undo them immediately,
12918 yielding an infinite loop. */
12922 /* Convert A ? B : 0 into A && B if A and B are truth values. */
12931 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
12936 {
12938 /* Only perform transformation if ARG0 is easily inverted. */
12942 ? BIT_IOR_EXPR
12945 op1);
12946 }
12948 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
12953 {
12955 /* Only perform transformation if ARG0 is easily inverted. */
12961 op2);
12962 }
12964 /* Convert A ? 1 : B into A || B if A and B are truth values. */
12976 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
12977 of fold_ternary on them. */
12987 {
12989 unsigned HOST_WIDE_INT width
13000 {
13005 {
13007 {
13012 }
13018 }
13019 }
13020 }
13022 /* On constants we can use native encode/interpret to constant
13023 fold (nearly) all BIT_FIELD_REFs. */
13029 {
13032 /* Limit us to a reasonable amount of work. To relax the
13033 other limitations we need bit-shifting of the buffer
13034 and rounding up the size. */
13038 {
13040 unsigned HOST_WIDE_INT len
13045 {
13050 }
13051 }
13052 }
13057 /* Perform constant folding of BIT_INSERT_EXPR. */
13061 {
13062 /* Build a vector of integers from the tree mask. */
13063 vec_perm_builder builder;
13067 /* Create a vec_perm_indices for the integer vector. */
13072 }
13076 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13079 {
13085 wide_int tem2
13089 }
13094 {
13096 unsigned HOST_WIDE_INT elsize
13099 {
13105 {
13111 }
13112 }
13113 }
13119 }
13121 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13122 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13123 constructor element index of the value returned. If the element is
13124 not found NULL_TREE is returned and *CTOR_IDX is updated to
13125 the index of the element after the ACCESS_INDEX position (which
13126 may be outside of the CTOR array). */
13128 tree
13131 {
13137 {
13140 {
13141 /* Static constructors for variably sized objects makes no sense. */
13144 /* ??? When it is obvious that the range is signed, treat it so. */
13149 {
13151 low_bound
13153 SIGNED);
13154 }
13155 else
13156 {
13159 }
13160 }
13161 }
13165 index_sgn);
13177 {
13178 /* Array constructor might explicitly set index, or specify a range,
13179 or leave index NULL meaning that it is next index after previous
13180 one. */
13182 {
13184 max_index = index
13186 else
13187 {
13190 index_sgn);
13191 max_index
13193 index_sgn);
13195 }
13196 }
13198 {
13204 }
13205 else
13208 /* Do we have match? */
13210 {
13212 {
13216 }
13217 }
13219 /* We're past the element we search for. Note during parsing
13220 the elements might not be sorted.
13221 ??? We should use a binary search and a flag on the
13222 CONSTRUCTOR as to whether elements are sorted in declaration
13223 order. */
13225 }
13229 }
13231 /* Perform constant folding and related simplification of EXPR.
13232 The related simplifications include x*1 => x, x*0 => 0, etc.,
13233 and application of the associative law.
13234 NOP_EXPR conversions may be removed freely (as long as we
13235 are careful not to change the type of the overall expression).
13236 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13237 but we can constant-fold them if they have constant operands. */
13239 #ifdef ENABLE_FOLD_CHECKING
13240 # define fold(x) fold_1 (x)
13242 static
13243 #endif
13244 tree
13246 {
13250 tree tem;
13253 /* Return right away if a constant. */
13257 /* CALL_EXPR-like objects with variable numbers of operands are
13258 treated specially. */
13260 {
13262 {
13265 }
13267 }
13270 {
13275 {
13293 }
13294 }
13297 {
13299 {
13306 {
13311 }
13314 }
13316 /* Return a VECTOR_CST if possible. */
13318 {
13324 tree val;
13330 }
13338 }
13340 #ifdef ENABLE_FOLD_CHECKING
13341 #undef fold
13348 /* When --enable-checking=fold, compute a digest of expr before
13349 and after actual fold call to see if fold did not accidentally
13350 change original expr. */
13352 tree
13354 {
13355 tree ret;
13375 }
13377 void
13379 {
13390 }
13392 static void
13394 {
13396 }
13398 static void
13401 {
13407 recursive_label:
13417 {
13418 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13426 }
13434 {
13435 /* Allow these fields to be modified. */
13436 tree tmp;
13447 {
13450 }
13451 }
13453 {
13454 /* Allow TREE_NO_WARNING to be set. Perhaps we shouldn't allow that
13455 and change builtins.c etc. instead - see PR89543. */
13461 }
13472 {
13475 {
13491 }
13495 {
13508 }
13525 {
13531 }
13534 {
13536 {
13539 }
13541 }
13552 {
13555 }
13565 }
13566 }
13568 /* Helper function for outputting the checksum of a tree T. When
13569 debugging with gdb, you can "define mynext" to be "next" followed
13570 by "call debug_fold_checksum (op0)", then just trace down till the
13571 outputs differ. */
13573 DEBUG_FUNCTION void
13575 {
13590 }
13592 #endif
13594 /* Fold a unary tree expression with code CODE of type TYPE with an
13595 operand OP0. LOC is the location of the resulting expression.
13596 Return a folded expression if successful. Otherwise, return a tree
13597 expression with code CODE of type TYPE with an operand OP0. */
13599 tree
13602 {
13603 tree tem;
13604 #ifdef ENABLE_FOLD_CHECKING
13613 #endif
13619 #ifdef ENABLE_FOLD_CHECKING
13626 #endif
13628 }
13630 /* Fold a binary tree expression with code CODE of type TYPE with
13631 operands OP0 and OP1. LOC is the location of the resulting
13632 expression. Return a folded expression if successful. Otherwise,
13633 return a tree expression with code CODE of type TYPE with operands
13634 OP0 and OP1. */
13636 tree
13639 MEM_STAT_DECL)
13640 {
13641 tree tem;
13642 #ifdef ENABLE_FOLD_CHECKING
13659 #endif
13665 #ifdef ENABLE_FOLD_CHECKING
13680 #endif
13682 }
13684 /* Fold a ternary tree expression with code CODE of type TYPE with
13685 operands OP0, OP1, and OP2. Return a folded expression if
13686 successful. Otherwise, return a tree expression with code CODE of
13687 type TYPE with operands OP0, OP1, and OP2. */
13689 tree
13692 {
13693 tree tem;
13694 #ifdef ENABLE_FOLD_CHECKING
13718 #endif
13725 #ifdef ENABLE_FOLD_CHECKING
13748 #endif
13750 }
13752 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13753 arguments in ARGARRAY, and a null static chain.
13754 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13755 of type TYPE from the given operands as constructed by build_call_array. */
13757 tree
13760 {
13761 tree tem;
13762 #ifdef ENABLE_FOLD_CHECKING
13781 #endif
13787 #ifdef ENABLE_FOLD_CHECKING
13803 #endif
13805 }
13807 /* Perform constant folding and related simplification of initializer
13808 expression EXPR. These behave identically to "fold_buildN" but ignore
13809 potential run-time traps and exceptions that fold must preserve. */
13811 #define START_FOLD_INIT \
13812 int saved_signaling_nans = flag_signaling_nans;\
13813 int saved_trapping_math = flag_trapping_math;\
13814 int saved_rounding_math = flag_rounding_math;\
13815 int saved_trapv = flag_trapv;\
13816 int saved_folding_initializer = folding_initializer;\
13817 flag_signaling_nans = 0;\
13818 flag_trapping_math = 0;\
13819 flag_rounding_math = 0;\
13820 flag_trapv = 0;\
13821 folding_initializer = 1;
13823 #define END_FOLD_INIT \
13824 flag_signaling_nans = saved_signaling_nans;\
13825 flag_trapping_math = saved_trapping_math;\
13826 flag_rounding_math = saved_rounding_math;\
13827 flag_trapv = saved_trapv;\
13828 folding_initializer = saved_folding_initializer;
13830 tree
13833 {
13834 tree result;
13835 START_FOLD_INIT;
13839 END_FOLD_INIT;
13841 }
13843 tree
13846 {
13847 tree result;
13848 START_FOLD_INIT;
13852 END_FOLD_INIT;
13854 }
13856 tree
13859 {
13860 tree result;
13861 START_FOLD_INIT;
13865 END_FOLD_INIT;
13867 }
13869 #undef START_FOLD_INIT
13870 #undef END_FOLD_INIT
13872 /* Determine if first argument is a multiple of second argument. Return 0 if
13873 it is not, or we cannot easily determined it to be.
13875 An example of the sort of thing we care about (at this point; this routine
13876 could surely be made more general, and expanded to do what the *_DIV_EXPR's
13877 fold cases do now) is discovering that
13879 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13881 is a multiple of
13883 SAVE_EXPR (J * 8)
13885 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
13887 This code also handles discovering that
13889 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
13891 is a multiple of 8 so we don't have to worry about dealing with a
13892 possible remainder.
13894 Note that we *look* inside a SAVE_EXPR only to determine how it was
13895 calculated; it is not safe for fold to do much of anything else with the
13896 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
13897 at run time. For example, the latter example above *cannot* be implemented
13898 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
13899 evaluation time of the original SAVE_EXPR is not necessarily the same at
13900 the time the new expression is evaluated. The only optimization of this
13901 sort that would be valid is changing
13903 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
13905 divided by 8 to
13907 SAVE_EXPR (I) * SAVE_EXPR (J)
13909 (where the same SAVE_EXPR (J) is used in the original and the
13910 transformed version). */
13912 int
13914 {
13925 {
13927 /* Bitwise and provides a power of two multiple. If the mask is
13928 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
13936 {
13942 {
13945 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
13947 {
13951 {
13954 }
13955 }
13957 }
13958 }
13963 /* It is impossible to prove if op0 - op1 is multiple of bottom
13964 precisely, so be conservative here checking if both op0 and op1
13965 are multiple of bottom. Note we check the second operand first
13966 since it's usually simpler. */
13971 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
13972 as op0 - 3 if the expression has unsigned type. For example,
13973 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
13983 {
13985 /* const_binop may not detect overflow correctly,
13986 so check for it explicitly here. */
13994 }
13998 /* Can't handle conversions from non-integral or wider integral type. */
14004 /* fall through */
14021 SIGNED);
14027 {
14030 /* Check for special cases to see if top is defined as multiple
14031 of bottom:
14033 top = (X & ~(bottom - 1) ; bottom is power of 2
14035 or
14037 Y = X % bottom
14038 top = X - Y. */
14057 }
14059 /* fall through */
14067 }
14068 }
14070 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14071 This function returns true for integer expressions, and returns
14072 false if uncertain. */
14074 bool
14076 {
14081 {
14104 {
14105 CASE_CFN_FABS:
14107 CASE_CFN_FMAX:
14108 CASE_CFN_FMIN:
14113 }
14117 }
14118 }
14120 /* Return true if expression X evaluates to an infinity.
14121 This function returns false for integer expressions. */
14123 bool
14125 {
14129 {
14142 }
14143 }
14145 /* Return true if expression X could evaluate to an infinity.
14146 This function returns false for integer expressions, and returns
14147 true if uncertain. */
14149 bool
14151 {
14155 {
14168 }
14169 }
14171 /* Return true if expression X evaluates to a signaling NaN.
14172 This function returns false for integer expressions. */
14174 bool
14176 {
14180 {
14191 }
14192 }
14194 /* Return true if expression X could evaluate to a signaling NaN.
14195 This function returns false for integer expressions, and returns
14196 true if uncertain. */
14198 bool
14200 {
14204 {
14224 {
14225 CASE_CFN_FABS:
14227 CASE_CFN_FMAX:
14228 CASE_CFN_FMIN:
14233 }
14236 }
14237 }
14239 /* Return true if expression X evaluates to a NaN.
14240 This function returns false for integer expressions. */
14242 bool
14244 {
14248 {
14259 }
14260 }
14262 /* Return true if expression X could evaluate to a NaN.
14263 This function returns false for integer expressions, and returns
14264 true if uncertain. */
14266 bool
14268 {
14272 {
14297 {
14298 CASE_CFN_FABS:
14300 CASE_CFN_FMAX:
14301 CASE_CFN_FMIN:
14306 }
14309 }
14310 }
14312 #define tree_expr_nonnegative_warnv_p(X, Y) \
14315 #define RECURSE(X) \
14316 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14318 /* Return true if CODE or TYPE is known to be non-negative. */
14320 static bool
14322 {
14325 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14326 have a signed:1 type (where the value is -1 and 0). */
14329 }
14331 /* Return true if (CODE OP0) is known to be non-negative. If the return
14332 value is based on the assumption that signed overflow is undefined,
14333 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14334 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14336 bool
14339 {
14344 {
14346 /* We can't return 1 if flag_wrapv is set because
14347 ABS_EXPR<INT_MIN> = INT_MIN. */
14351 {
14354 }
14362 CASE_CONVERT:
14363 {
14368 {
14372 {
14376 }
14377 }
14379 {
14385 }
14386 }
14391 }
14393 /* We don't know sign of `t', so be conservative and return false. */
14395 }
14397 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14398 value is based on the assumption that signed overflow is undefined,
14399 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14400 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14402 bool
14406 {
14411 {
14417 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14418 both unsigned and at least 2 bits shorter than the result. */
14422 {
14427 {
14431 }
14432 }
14437 {
14438 /* x * x is always non-negative for floating point x
14439 or without overflow. */
14442 {
14447 }
14448 }
14450 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14451 both unsigned and their total bits is shorter than the result. */
14455 {
14474 {
14484 }
14485 }
14492 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14493 things. */
14518 }
14520 /* We don't know sign of `t', so be conservative and return false. */
14522 }
14524 /* Return true if T is known to be non-negative. If the return
14525 value is based on the assumption that signed overflow is undefined,
14526 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14527 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14529 bool
14531 {
14536 {
14550 /* Limit the depth of recursion to avoid quadratic behavior.
14551 This is expected to catch almost all occurrences in practice.
14552 If this code misses important cases that unbounded recursion
14553 would not, passes that need this information could be revised
14554 to provide it through dataflow propagation. */
14562 }
14563 }
14565 /* Return true if T is known to be non-negative. If the return
14566 value is based on the assumption that signed overflow is undefined,
14567 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14568 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14570 bool
14573 {
14575 {
14576 CASE_CFN_ACOS:
14577 CASE_CFN_ACOSH:
14578 CASE_CFN_CABS:
14579 CASE_CFN_COSH:
14580 CASE_CFN_ERFC:
14581 CASE_CFN_EXP:
14582 CASE_CFN_EXP10:
14583 CASE_CFN_EXP2:
14584 CASE_CFN_FABS:
14585 CASE_CFN_FDIM:
14586 CASE_CFN_HYPOT:
14587 CASE_CFN_POW10:
14588 CASE_CFN_FFS:
14589 CASE_CFN_PARITY:
14590 CASE_CFN_POPCOUNT:
14591 CASE_CFN_CLZ:
14592 CASE_CFN_CLRSB:
14597 /* Always true. */
14600 CASE_CFN_SQRT:
14601 CASE_CFN_SQRT_FN:
14602 /* sqrt(-0.0) is -0.0. */
14607 CASE_CFN_ASINH:
14608 CASE_CFN_ATAN:
14609 CASE_CFN_ATANH:
14610 CASE_CFN_CBRT:
14611 CASE_CFN_CEIL:
14612 CASE_CFN_CEIL_FN:
14613 CASE_CFN_ERF:
14614 CASE_CFN_EXPM1:
14615 CASE_CFN_FLOOR:
14616 CASE_CFN_FLOOR_FN:
14617 CASE_CFN_FMOD:
14618 CASE_CFN_FREXP:
14619 CASE_CFN_ICEIL:
14620 CASE_CFN_IFLOOR:
14621 CASE_CFN_IRINT:
14622 CASE_CFN_IROUND:
14623 CASE_CFN_LCEIL:
14624 CASE_CFN_LDEXP:
14625 CASE_CFN_LFLOOR:
14626 CASE_CFN_LLCEIL:
14627 CASE_CFN_LLFLOOR:
14628 CASE_CFN_LLRINT:
14629 CASE_CFN_LLROUND:
14630 CASE_CFN_LRINT:
14631 CASE_CFN_LROUND:
14632 CASE_CFN_MODF:
14633 CASE_CFN_NEARBYINT:
14634 CASE_CFN_NEARBYINT_FN:
14635 CASE_CFN_RINT:
14636 CASE_CFN_RINT_FN:
14637 CASE_CFN_ROUND:
14638 CASE_CFN_ROUND_FN:
14639 CASE_CFN_ROUNDEVEN:
14640 CASE_CFN_ROUNDEVEN_FN:
14641 CASE_CFN_SCALB:
14642 CASE_CFN_SCALBLN:
14643 CASE_CFN_SCALBN:
14644 CASE_CFN_SIGNBIT:
14645 CASE_CFN_SIGNIFICAND:
14646 CASE_CFN_SINH:
14647 CASE_CFN_TANH:
14648 CASE_CFN_TRUNC:
14649 CASE_CFN_TRUNC_FN:
14650 /* True if the 1st argument is nonnegative. */
14653 CASE_CFN_FMAX:
14654 CASE_CFN_FMAX_FN:
14655 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14656 things. In the presence of sNaNs, we're only guaranteed to be
14657 non-negative if both operands are non-negative. In the presence
14658 of qNaNs, we're non-negative if either operand is non-negative
14659 and can't be a qNaN, or if both operands are non-negative. */
14668 CASE_CFN_FMIN:
14669 CASE_CFN_FMIN_FN:
14670 /* True if the 1st AND 2nd arguments are nonnegative. */
14673 CASE_CFN_COPYSIGN:
14674 CASE_CFN_COPYSIGN_FN:
14675 /* True if the 2nd argument is nonnegative. */
14678 CASE_CFN_POWI:
14679 /* True if the 1st argument is nonnegative or the second
14680 argument is an even integer. */
14686 CASE_CFN_POW:
14687 /* True if the 1st argument is nonnegative or the second
14688 argument is an even integer valued real. */
14690 {
14691 REAL_VALUE_TYPE c;
14692 HOST_WIDE_INT n;
14697 {
14698 REAL_VALUE_TYPE cint;
14702 }
14703 }
14708 }
14710 }
14712 /* Return true if T is known to be non-negative. If the return
14713 value is based on the assumption that signed overflow is undefined,
14714 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14715 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14717 static bool
14719 {
14725 {
14727 {
14731 /* If the initializer is non-void, then it's a normal expression
14732 that will be assigned to the slot. */
14736 /* Otherwise, the initializer sets the slot in some way. One common
14737 way is an assignment statement at the end of the initializer. */
14739 {
14747 else
14749 }
14755 }
14758 {
14764 arg0,
14765 arg1,
14767 }
14780 }
14781 }
14783 #undef RECURSE
14784 #undef tree_expr_nonnegative_warnv_p
14786 /* Return true if T is known to be non-negative. If the return
14787 value is based on the assumption that signed overflow is undefined,
14788 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14789 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14791 bool
14793 {
14800 {
14822 }
14825 {
14851 }
14852 }
14854 /* Return true if `t' is known to be non-negative. Handle warnings
14855 about undefined signed overflow. */
14857 bool
14859 {
14866 "determining that expression is always "
14868 WARN_STRICT_OVERFLOW_MISC);
14870 }
14873 /* Return true when (CODE OP0) is an address and is known to be nonzero.
14874 For floating point we further ensure that T is not denormal.
14875 Similar logic is present in nonzero_address in rtlanal.h.
14877 If the return value is based on the assumption that signed overflow
14878 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14879 change *STRICT_OVERFLOW_P. */
14881 bool
14884 {
14886 {
14889 strict_overflow_p);
14892 {
14898 strict_overflow_p));
14899 }
14904 strict_overflow_p);
14908 }
14911 }
14913 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
14914 For floating point we further ensure that T is not denormal.
14915 Similar logic is present in nonzero_address in rtlanal.h.
14917 If the return value is based on the assumption that signed overflow
14918 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
14919 change *STRICT_OVERFLOW_P. */
14921 bool
14923 tree type,
14924 tree op0,
14926 {
14929 {
14933 {
14934 /* With the presence of negative values it is hard
14935 to say something. */
14942 /* One of operands must be positive and the other non-negative. */
14943 /* We don't set *STRICT_OVERFLOW_P here: even if this value
14944 overflows, on a twos-complement machine the sum of two
14945 nonnegative numbers can never be zero. */
14947 strict_overflow_p)
14949 strict_overflow_p));
14950 }
14955 {
14957 strict_overflow_p)
14959 strict_overflow_p))
14960 {
14963 }
14964 }
14973 {
14976 }
14983 {
14987 /* When both operands are nonzero, then MAX must be too. */
14989 strict_overflow_p))
14992 /* MAX where operand 0 is positive is positive. */
14994 strict_overflow_p);
14995 }
14996 /* MAX where operand 1 is positive is positive. */
15001 {
15005 }
15010 strict_overflow_p)
15012 strict_overflow_p));
15016 }
15019 }
15021 /* Return true when T is an address and is known to be nonzero.
15022 For floating point we further ensure that T is not denormal.
15023 Similar logic is present in nonzero_address in rtlanal.h.
15025 If the return value is based on the assumption that signed overflow
15026 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15027 change *STRICT_OVERFLOW_P. */
15029 bool
15031 {
15034 {
15039 {
15051 /* For objects in symbol table check if we know they are non-zero.
15052 Don't do anything for variables and functions before symtab is built;
15053 it is quite possible that they will be declared weak later. */
15058 /* Constants are never weak. */
15063 }
15071 {
15075 }
15085 }
15087 }
15089 #define integer_valued_real_p(X) \
15092 #define RECURSE(X) \
15093 ((integer_valued_real_p) (X, depth + 1))
15095 /* Return true if the floating point result of (CODE OP0) has an
15096 integer value. We also allow +Inf, -Inf and NaN to be considered
15097 integer values. Return false for signaling NaN.
15099 DEPTH is the current nesting depth of the query. */
15101 bool
15103 {
15105 {
15112 CASE_CONVERT:
15113 {
15120 }
15124 }
15126 }
15128 /* Return true if the floating point result of (CODE OP0 OP1) has an
15129 integer value. We also allow +Inf, -Inf and NaN to be considered
15130 integer values. Return false for signaling NaN.
15132 DEPTH is the current nesting depth of the query. */
15134 bool
15136 {
15138 {
15148 }
15150 }
15152 /* Return true if the floating point result of calling FNDECL with arguments
15153 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15154 considered integer values. Return false for signaling NaN. If FNDECL
15155 takes fewer than 2 arguments, the remaining ARGn are null.
15157 DEPTH is the current nesting depth of the query. */
15159 bool
15161 {
15163 {
15164 CASE_CFN_CEIL:
15165 CASE_CFN_CEIL_FN:
15166 CASE_CFN_FLOOR:
15167 CASE_CFN_FLOOR_FN:
15168 CASE_CFN_NEARBYINT:
15169 CASE_CFN_NEARBYINT_FN:
15170 CASE_CFN_RINT:
15171 CASE_CFN_RINT_FN:
15172 CASE_CFN_ROUND:
15173 CASE_CFN_ROUND_FN:
15174 CASE_CFN_ROUNDEVEN:
15175 CASE_CFN_ROUNDEVEN_FN:
15176 CASE_CFN_TRUNC:
15177 CASE_CFN_TRUNC_FN:
15180 CASE_CFN_FMIN:
15181 CASE_CFN_FMIN_FN:
15182 CASE_CFN_FMAX:
15183 CASE_CFN_FMAX_FN:
15188 }
15190 }
15192 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15193 has an integer value. We also allow +Inf, -Inf and NaN to be
15194 considered integer values. Return false for signaling NaN.
15196 DEPTH is the current nesting depth of the query. */
15198 bool
15200 {
15202 {
15210 /* Limit the depth of recursion to avoid quadratic behavior.
15211 This is expected to catch almost all occurrences in practice.
15212 If this code misses important cases that unbounded recursion
15213 would not, passes that need this information could be revised
15214 to provide it through dataflow propagation. */
15218 depth));
15222 }
15224 }
15226 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15227 has an integer value. We also allow +Inf, -Inf and NaN to be
15228 considered integer values. Return false for signaling NaN.
15230 DEPTH is the current nesting depth of the query. */
15232 static bool
15234 {
15236 {
15247 }
15249 }
15251 #undef RECURSE
15252 #undef integer_valued_real_p
15254 /* Return true if the floating point expression T has an integer value.
15255 We also allow +Inf, -Inf and NaN to be considered integer values.
15256 Return false for signaling NaN.
15258 DEPTH is the current nesting depth of the query. */
15260 bool
15262 {
15270 {
15286 }
15289 {
15295 {
15304 }
15308 }
15309 }
15311 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15312 attempt to fold the expression to a constant without modifying TYPE,
15313 OP0 or OP1.
15315 If the expression could be simplified to a constant, then return
15316 the constant. If the expression would not be simplified to a
15317 constant, then return NULL_TREE. */
15319 tree
15321 {
15324 }
15326 /* Given the components of a unary expression CODE, TYPE and OP0,
15327 attempt to fold the expression to a constant without modifying
15328 TYPE or OP0.
15330 If the expression could be simplified to a constant, then return
15331 the constant. If the expression would not be simplified to a
15332 constant, then return NULL_TREE. */
15334 tree
15336 {
15339 }
15341 /* If EXP represents referencing an element in a constant string
15342 (either via pointer arithmetic or array indexing), return the
15343 tree representing the value accessed, otherwise return NULL. */
15345 tree
15347 {
15351 {
15353 tree index;
15354 tree string;
15359 else
15360 {
15364 /* Optimize the special-case of a zero lower bound.
15366 We convert the low_bound to sizetype to avoid some problems
15367 with constant folding. (E.g. suppose the lower bound is 1,
15368 and its mode is QI. Without the conversion,l (ARRAY
15369 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15370 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15376 }
15378 scalar_int_mode char_mode;
15390 }
15392 }
15394 /* Folds a read from vector element at IDX of vector ARG. */
15396 tree
15398 {
15403 {
15407 {
15411 }
15412 }
15414 }
15416 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15417 an integer constant, real, or fixed-point constant.
15419 TYPE is the type of the result. */
15421 static tree
15423 {
15427 {
15433 {
15434 FIXED_VALUE_TYPE f;
15439 /* Propagate overflow flags. */
15443 }
15447 {
15454 }
15457 }
15460 }
15462 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15463 an integer constant or real constant.
15465 TYPE is the type of the result. */
15467 tree
15469 {
15473 {
15475 {
15476 /* If the value is unsigned or non-negative, then the absolute value
15477 is the same as the ordinary value. */
15481 ;
15483 /* If the value is negative, then the absolute value is
15484 its negation. */
15485 else
15488 /* Force to the destination type, set TREE_OVERFLOW for signed
15489 TYPE only. */
15491 }
15497 else
15503 }
15506 }
15508 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15509 constant. TYPE is the type of the result. */
15511 static tree
15513 {
15517 }
15519 /* Given CODE, a relational operator, the target type, TYPE and two
15520 constant operands OP0 and OP1, return the result of the
15521 relational operation. If the result is not a compile time
15522 constant, then return NULL_TREE. */
15524 static tree
15526 {
15529 /* From here on, the only cases we handle are when the result is
15530 known to be a constant. */
15533 {
15537 /* Handle the cases where either operand is a NaN. */
15539 {
15541 {
15569 }
15572 }
15575 }
15578 {
15582 }
15584 /* Handle equality/inequality of complex constants. */
15586 {
15597 else
15599 }
15602 {
15604 {
15605 /* Have vector comparison with scalar boolean result. */
15613 {
15621 }
15623 }
15624 tree_vector_builder elts;
15629 {
15642 }
15645 }
15647 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15649 To compute GT, swap the arguments and do LT.
15650 To compute GE, do LT and invert the result.
15651 To compute LE, swap the arguments, do LT and invert the result.
15652 To compute NE, do EQ and invert the result.
15654 Therefore, the code below must handle only EQ and LT. */
15657 {
15660 }
15662 /* Note that it is safe to invert for real values here because we
15663 have already handled the one case that it matters. */
15667 {
15670 }
15672 /* Compute a result for LT or EQ if args permit;
15673 Otherwise return T. */
15675 {
15678 else
15680 }
15681 else
15687 }
15689 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15690 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15691 itself. */
15693 tree
15695 {
15696 /* If the expression does not have side effects then we don't have to wrap
15697 it with a cleanup point expression. */
15701 /* If the expression is a return, check to see if the expression inside the
15702 return has no side effects or the right hand side of the modify expression
15703 inside the return. If either don't have side effects set we don't need to
15704 wrap the expression in a cleanup point expression. Note we don't check the
15705 left hand side of the modify because it should always be a return decl. */
15707 {
15714 }
15717 }
15719 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15720 of an indirection through OP0, or NULL_TREE if no simplification is
15721 possible. */
15723 tree
15725 {
15727 tree subtype;
15728 poly_uint64 const_op01;
15737 {
15741 /* *&CONST_DECL -> to the value of the const decl. */
15744 /* *&p => p; make sure to handle *&"str"[cst] here. */
15746 {
15750 else
15752 }
15753 /* *(foo *)&fooarray => fooarray[0] */
15756 && (!in_gimple_form
15758 {
15768 }
15769 /* *(foo *)&complexfoo => __real__ complexfoo */
15773 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
15776 {
15780 index);
15781 }
15782 }
15786 {
15792 {
15793 tree op00type;
15797 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
15800 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
15801 but we want to treat offsets with MSB set as negative.
15802 For the code below negative offsets are invalid and
15803 TYPE_SIZE of the element is something unsigned, so
15804 check whether op01 fits into poly_int64, which implies
15805 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
15806 then just use poly_uint64 because we want to treat the
15807 value as unsigned. */
15809 {
15811 poly_uint64 max_offset
15815 {
15820 }
15821 }
15822 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
15825 {
15827 const_op01))
15829 }
15830 /* ((foo *)&fooarray)[1] => fooarray[1] */
15833 {
15842 {
15847 }
15848 }
15849 }
15850 }
15852 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
15855 && (!in_gimple_form
15857 {
15858 tree type_domain;
15868 NULL_TREE);
15869 }
15872 }
15874 /* Builds an expression for an indirection through T, simplifying some
15875 cases. */
15877 tree
15879 {
15887 }
15889 /* Given an INDIRECT_REF T, return either T or a simplified version. */
15891 tree
15893 {
15898 else
15900 }
15902 /* Strip non-trapping, non-side-effecting tree nodes from an expression
15903 whose result is ignored. The type of the returned tree need not be
15904 the same as the original expression. */
15906 tree
15908 {
15914 {
15925 else
15931 {
15947 }
15952 }
15953 }
15955 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
15957 tree
15959 {
15965 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
15966 have to do anything. Only do this when we are not given a const,
15967 because in that case, this check is more expensive than just
15968 doing it. */
15970 {
15975 }
15977 /* If divisor is a power of two, simplify this to bit manipulation. */
15979 {
15981 {
15995 }
15996 else
15997 {
15998 tree t;
16004 }
16005 }
16006 else
16007 {
16012 }
16015 }
16017 /* Likewise, but round down. */
16019 tree
16021 {
16028 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16029 have to do anything. Only do this when we are not given a const,
16030 because in that case, this check is more expensive than just
16031 doing it. */
16033 {
16038 }
16040 /* If divisor is a power of two, simplify this to bit manipulation. */
16042 {
16043 tree t;
16047 }
16048 else
16049 {
16054 }
16057 }
16059 /* Returns the pointer to the base of the object addressed by EXP and
16060 extracts the information about the offset of the access, storing it
16061 to PBITPOS and POFFSET. */
16063 static tree
16066 {
16067 tree core;
16068 machine_mode mode;
16070 poly_int64 bitsize;
16074 {
16079 }
16081 {
16087 {
16088 poly_offset_int tem
16094 }
16095 }
16096 else
16097 {
16101 }
16104 }
16106 /* Returns true if addresses of E1 and E2 differ by a constant, false
16107 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16109 bool
16111 {
16126 {
16136 }
16138 {
16139 /* If only one of the offsets is non-constant, the difference cannot
16140 be a constant. */
16142 }
16143 else
16148 }
16150 /* Return OFF converted to a pointer offset type suitable as offset for
16151 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16152 tree
16154 {
16158 }
16160 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16161 tree
16163 {
16166 }
16168 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16169 tree
16171 {
16174 }
16176 /* Return a pointer to a NUL-terminated string containing the sequence
16177 of bytes corresponding to the representation of the object referred to
16178 by SRC (or a subsequence of such bytes within it if SRC is a reference
16179 to an initialized constant array plus some constant offset).
16180 Set *STRSIZE the number of bytes in the constant sequence including
16181 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16182 where A is the array that stores the constant sequence that SRC points
16183 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16184 need not point to a string or even an array of characters but may point
16185 to an object of any type. */
16189 {
16190 /* The offset into the array A storing the string, and A's byte size. */
16191 tree offset_node;
16192 tree mem_size;
16199 else
16206 {
16209 else
16211 }
16216 /* ARRAY_SIZE is the byte size of the array the constant sequence
16217 is stored in and equal to sizeof A. INIT_BYTES is the number
16218 of bytes in the constant sequence used to initialize the array,
16219 including any embedded NULs as well as the terminating NUL (for
16220 strings), but not including any trailing zeros/NULs past
16221 the terminating one appended implicitly to a string literal to
16222 zero out the remainder of the array it's stored in. For example,
16223 given:
16224 const char a[7] = "abc\0d";
16225 n = strlen (a + 1);
16226 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16227 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16228 is equal to strlen (A) + 1. */
16233 /* Ideally this would turn into a gcc_checking_assert over time. */
16241 {
16242 /* Compute and store the number of characters from the beginning
16243 of the substring at OFFSET to the end, including the terminating
16244 nul. Offsets past the initial length refer to null strings. */
16247 else
16249 }
16250 else
16251 {
16253 /* Support only properly NUL-terminated single byte strings. */
16258 }
16261 }
16263 /* Return a pointer to a NUL-terminated string corresponding to
16264 the expression STR referencing a constant string, possibly
16265 involving a constant offset. Return null if STR either doesn't
16266 reference a constant string or if it involves a nonconstant
16267 offset. */
16271 {
16273 }
16275 /* Given a tree T, compute which bits in T may be nonzero. */
16277 wide_int
16279 {
16281 {
16299 CASE_CONVERT:
16305 {
16310 }
16314 {
16322 }
16326 {
16334 }
16338 }
16341 }
16343 #if CHECKING_P
16347 /* Helper functions for writing tests of folding trees. */
16349 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16351 static void
16353 tree constant)
16354 {
16356 }
16358 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16359 wrapping WRAPPED_EXPR. */
16361 static void
16363 tree wrapped_expr)
16364 {
16369 }
16371 /* Verify that various arithmetic binary operations are folded
16372 correctly. */
16374 static void
16376 {
16382 /* Addition. */
16383 /* 1 <-- (0 + 1) */
16385 one);
16387 one);
16389 /* (nonlvalue)x <-- (x + 0) */
16391 x);
16393 /* Subtraction. */
16394 /* 0 <-- (x - x) */
16396 zero);
16398 x);
16400 /* Multiplication. */
16401 /* 0 <-- (x * 0) */
16403 zero);
16405 /* (nonlvalue)x <-- (x * 1) */
16407 x);
16408 }
16410 /* Verify that various binary operations on vectors are folded
16411 correctly. */
16413 static void
16415 {
16422 /* Verify equality tests that return a scalar boolean result. */
16435 }
16437 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16439 static void
16441 {
16444 /* This will be 1 if VEC_MODE isn't a vector mode. */
16451 }
16453 /* Run all of the selftests within this file. */
16455 void
16457 {
16461 }