| blob | 7e5494dfd392105ee3e28583ebede49b61580f7b |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2023 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. */
89 /* Nonzero if we are folding constants inside an initializer or a C++
90 manifestly-constant-evaluated context; zero otherwise.
91 Should be used when folding in initializer enables additional
92 optimizations. */
95 /* Nonzero if we are folding C++ manifestly-constant-evaluated context; zero
96 otherwise.
97 Should be used when certain constructs shouldn't be optimized
98 during folding in that context. */
101 /* The following constants represent a bit based encoding of GCC's
102 comparison operators. This encoding simplifies transformations
103 on relational comparison operators, such as AND and OR. */
121 };
153 /* This is a helper function to detect min/max for some operands of COND_EXPR.
154 The form is "(EXP0 CMP EXP1) ? EXP2 : EXP3". */
155 tree_code
157 {
167 {
169 {
170 /* X <= Y - 1 equals to X < Y. */
173 /* X > Y - 1 equals to X >= Y. */
176 /* a != MIN_RANGE<a> ? a : MIN_RANGE<a>+1 -> MAX_EXPR<MIN_RANGE<a>+1, a> */
178 {
179 value_range r;
188 }
189 }
191 {
192 /* X < Y + 1 equals to X <= Y. */
195 /* X >= Y + 1 equals to X > Y. */
198 /* a != MAX_RANGE<a> ? a : MAX_RANGE<a>-1 -> MIN_EXPR<MIN_RANGE<a>-1, a> */
200 {
201 value_range r;
210 }
211 }
212 }
215 {
220 }
222 }
224 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
225 Otherwise, return LOC. */
227 static location_t
229 {
232 }
234 /* Similar to protected_set_expr_location, but never modify x in place,
235 if location can and needs to be set, unshare it. */
237 tree
239 {
245 {
248 }
250 }
251 \f
252 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
253 division and returns the quotient. Otherwise returns
254 NULL_TREE. */
256 tree
258 {
259 widest_int quo;
266 }
267 \f
268 /* This is nonzero if we should defer warnings about undefined
269 overflow. This facility exists because these warnings are a
270 special case. The code to estimate loop iterations does not want
271 to issue any warnings, since it works with expressions which do not
272 occur in user code. Various bits of cleanup code call fold(), but
273 only use the result if it has certain characteristics (e.g., is a
274 constant); that code only wants to issue a warning if the result is
275 used. */
279 /* If a warning about undefined overflow is deferred, this is the
280 warning. Note that this may cause us to turn two warnings into
281 one, but that is fine since it is sufficient to only give one
282 warning per expression. */
286 /* If a warning about undefined overflow is deferred, this is the
287 level at which the warning should be emitted. */
291 /* Start deferring overflow warnings. We could use a stack here to
292 permit nested calls, but at present it is not necessary. */
294 void
296 {
298 }
300 /* Stop deferring overflow warnings. If there is a pending warning,
301 and ISSUE is true, then issue the warning if appropriate. STMT is
302 the statement with which the warning should be associated (used for
303 location information); STMT may be NULL. CODE is the level of the
304 warning--a warn_strict_overflow_code value. This function will use
305 the smaller of CODE and the deferred code when deciding whether to
306 issue the warning. CODE may be zero to mean to always use the
307 deferred code. */
309 void
311 {
313 location_t locus;
318 {
324 }
335 /* Use the smallest code level when deciding to issue the
336 warning. */
345 else
348 }
350 /* Stop deferring overflow warnings, ignoring any deferred
351 warnings. */
353 void
355 {
357 }
359 /* Whether we are deferring overflow warnings. */
361 bool
363 {
365 }
367 /* This is called when we fold something based on the fact that signed
368 overflow is undefined. */
370 void
372 {
374 {
377 {
380 }
381 }
384 }
385 \f
386 /* Return true if the built-in mathematical function specified by CODE
387 is odd, i.e. -f(x) == f(-x). */
389 bool
391 {
393 {
394 CASE_CFN_ASIN:
395 CASE_CFN_ASIN_FN:
396 CASE_CFN_ASINH:
397 CASE_CFN_ASINH_FN:
398 CASE_CFN_ATAN:
399 CASE_CFN_ATAN_FN:
400 CASE_CFN_ATANH:
401 CASE_CFN_ATANH_FN:
402 CASE_CFN_CASIN:
403 CASE_CFN_CASIN_FN:
404 CASE_CFN_CASINH:
405 CASE_CFN_CASINH_FN:
406 CASE_CFN_CATAN:
407 CASE_CFN_CATAN_FN:
408 CASE_CFN_CATANH:
409 CASE_CFN_CATANH_FN:
410 CASE_CFN_CBRT:
411 CASE_CFN_CBRT_FN:
412 CASE_CFN_CPROJ:
413 CASE_CFN_CPROJ_FN:
414 CASE_CFN_CSIN:
415 CASE_CFN_CSIN_FN:
416 CASE_CFN_CSINH:
417 CASE_CFN_CSINH_FN:
418 CASE_CFN_CTAN:
419 CASE_CFN_CTAN_FN:
420 CASE_CFN_CTANH:
421 CASE_CFN_CTANH_FN:
422 CASE_CFN_ERF:
423 CASE_CFN_ERF_FN:
424 CASE_CFN_LLROUND:
425 CASE_CFN_LLROUND_FN:
426 CASE_CFN_LROUND:
427 CASE_CFN_LROUND_FN:
428 CASE_CFN_ROUND:
429 CASE_CFN_ROUNDEVEN:
430 CASE_CFN_ROUNDEVEN_FN:
431 CASE_CFN_SIN:
432 CASE_CFN_SIN_FN:
433 CASE_CFN_SINH:
434 CASE_CFN_SINH_FN:
435 CASE_CFN_TAN:
436 CASE_CFN_TAN_FN:
437 CASE_CFN_TANH:
438 CASE_CFN_TANH_FN:
439 CASE_CFN_TRUNC:
440 CASE_CFN_TRUNC_FN:
443 CASE_CFN_LLRINT:
444 CASE_CFN_LLRINT_FN:
445 CASE_CFN_LRINT:
446 CASE_CFN_LRINT_FN:
447 CASE_CFN_NEARBYINT:
448 CASE_CFN_NEARBYINT_FN:
449 CASE_CFN_RINT:
450 CASE_CFN_RINT_FN:
455 }
457 }
459 /* Check whether we may negate an integer constant T without causing
460 overflow. */
462 bool
464 {
465 tree type;
474 }
476 /* Determine whether an expression T can be cheaply negated using
477 the function negate_expr without introducing undefined overflow. */
479 static bool
481 {
482 tree type;
491 {
496 /* Check that -CST will not overflow type. */
509 /* We want to canonicalize to positive real constants. Pretend
510 that only negative ones can be easily negated. */
518 {
522 /* Steps don't prevent negation. */
529 }
544 /* -(A + B) -> (-B) - A. */
547 /* -(A + B) -> (-A) - B. */
551 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
560 /* INT_MIN/n * n doesn't overflow while negating one operand it does
561 if n is a (negative) power of two. */
572 /* Fall through. */
585 /* In general we can't negate A in A / B, because if A is INT_MIN and
586 B is not 1 we change the sign of the result. */
590 /* In general we can't negate B in A / B, because if A is INT_MIN and
591 B is 1, we may turn this into INT_MIN / -1 which is undefined
592 and actually traps on some architectures. */
601 /* Negate -((double)float) as (double)(-float). */
603 {
607 }
611 /* Negate -f(x) as f(-x). */
617 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
619 {
623 }
628 }
630 }
632 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
633 simplification is possible.
634 If negate_expr_p would return true for T, NULL_TREE will never be
635 returned. */
637 static tree
639 {
641 tree tem;
644 {
645 /* Convert - (~A) to A + 1. */
669 {
674 }
678 {
679 tree_vector_builder elts;
683 {
688 }
691 }
714 {
715 /* -(A + B) -> (-B) - A. */
717 {
721 }
723 /* -(A + B) -> (-A) - B. */
725 {
729 }
730 }
734 /* - (A - B) -> B - A */
745 /* Fall through. */
749 {
758 }
766 /* In general we can't negate A in A / B, because if A is INT_MIN and
767 B is not 1 we change the sign of the result. */
773 /* In general we can't negate B in A / B, because if A is INT_MIN and
774 B is 1, we may turn this into INT_MIN / -1 which is undefined
775 and actually traps on some architectures. */
787 /* Convert -((double)float) into (double)(-float). */
789 {
793 }
797 /* Negate -f(x) as f(-x). */
800 {
806 }
810 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
812 {
815 {
822 }
823 }
828 }
831 }
833 /* A wrapper for fold_negate_expr_1. */
835 static tree
837 {
844 }
846 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T cannot be
847 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
848 return NULL_TREE. */
850 static tree
852 {
854 location_t loc;
867 }
868 \f
869 /* Split a tree IN into a constant, literal and variable parts that could be
870 combined with CODE to make IN. "constant" means an expression with
871 TREE_CONSTANT but that isn't an actual constant. CODE must be a
872 commutative arithmetic operation. Store the constant part into *CONP,
873 the literal in *LITP and return the variable part. If a part isn't
874 present, set it to null. If the tree does not decompose in this way,
875 return the entire tree as the variable part and the other parts as null.
877 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
878 case, we negate an operand that was subtracted. Except if it is a
879 literal for which we use *MINUS_LITP instead.
881 If NEGATE_P is true, we are negating all of IN, again except a literal
882 for which we use *MINUS_LITP instead. If a variable part is of pointer
883 type, it is negated after converting to TYPE. This prevents us from
884 generating illegal MINUS pointer expression. LOC is the location of
885 the converted variable part.
887 If IN is itself a literal or constant, return it as appropriate.
889 Note that we do not guarantee that any of the three values will be the
890 same type as IN, but they will have the same signedness and mode. */
892 static tree
896 {
904 /* Strip any conversions that don't change the machine mode or signedness. */
913 /* We can associate addition and subtraction together (even
914 though the C standard doesn't say so) for integers because
915 the value is not affected. For reals, the value might be
916 affected, so we can't. */
922 {
928 /* First see if either of the operands is a literal, then a constant. */
941 /* If we haven't dealt with either operand, this is not a case we can
942 decompose. Otherwise, VAR is either of the ones remaining, if any. */
947 else
950 /* Now do any needed negations. */
957 }
962 {
963 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
964 when IN is constant. */
967 }
968 else
972 {
985 }
995 }
997 /* Re-associate trees split by the above function. T1 and T2 are
998 either expressions to associate or null. Return the new
999 expression, if any. LOC is the location of the new expression. If
1000 we build an operation, do it in TYPE and with CODE. */
1002 static tree
1004 {
1006 {
1009 }
1013 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
1014 try to fold this since we will have infinite recursion. But do
1015 deal with any NEGATE_EXPRs. */
1019 {
1021 {
1034 }
1036 {
1039 }
1043 }
1047 }
1048 \f
1049 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
1050 for use in int_const_binop, size_binop and size_diffop. */
1052 static bool
1054 {
1061 {
1070 }
1075 }
1077 /* Combine two wide ints ARG1 and ARG2 under operation CODE to produce
1078 a new constant in RES. Return FALSE if we don't know how to
1079 evaluate CODE at compile-time. */
1081 bool
1085 {
1086 wide_int tmp;
1089 {
1111 /* It's unclear from the C standard whether shifts can overflow.
1112 The following code ignores overflow; perhaps a C standard
1113 interpretation ruling is needed. */
1120 {
1124 else
1126 }
1127 else
1132 else
1211 }
1213 }
1215 /* Combine two poly int's ARG1 and ARG2 under operation CODE to
1216 produce a new constant in RES. Return FALSE if we don't know how
1217 to evaluate CODE at compile-time. */
1219 static bool
1223 {
1227 {
1245 else
1252 else
1265 }
1267 }
1269 /* Combine two integer constants ARG1 and ARG2 under operation CODE to
1270 produce a new constant. Return NULL_TREE if we don't know how to
1271 evaluate CODE at compile-time. */
1273 tree
1276 {
1277 poly_wide_int poly_res;
1283 {
1289 }
1298 }
1300 /* Return true if binary operation OP distributes over addition in operand
1301 OPNO, with the other operand being held constant. OPNO counts from 1. */
1303 static bool
1305 {
1307 {
1318 }
1319 }
1321 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1322 constant. We assume ARG1 and ARG2 have the same data type, or at least
1323 are the same kind of constant and the same machine mode. Return zero if
1324 combining the constants is not allowed in the current operating mode. */
1326 static tree
1328 {
1329 /* Sanity check for the recursive cases. */
1337 {
1343 }
1346 {
1347 machine_mode mode;
1348 REAL_VALUE_TYPE d1;
1349 REAL_VALUE_TYPE d2;
1350 REAL_VALUE_TYPE value;
1351 REAL_VALUE_TYPE result;
1355 /* The following codes are handled by real_arithmetic. */
1357 {
1368 }
1376 /* Don't perform operation if we honor signaling NaNs and
1377 either operand is a signaling NaN. */
1383 /* Don't perform operation if it would raise a division
1384 by zero exception. */
1390 /* If either operand is a NaN, just return it. Otherwise, set up
1391 for floating-point trap; we return an overflow. */
1393 {
1394 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1395 is off. */
1399 }
1401 {
1402 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1403 is off. */
1407 }
1412 /* Don't constant fold this floating point operation if
1413 both operands are not NaN but the result is NaN, and
1414 flag_trapping_math. Such operations should raise an
1415 invalid operation exception. */
1423 /* Don't constant fold this floating point operation if
1424 the result has overflowed and flag_trapping_math. */
1432 /* Don't constant fold this floating point operation if the
1433 result may dependent upon the run-time rounding mode and
1434 flag_rounding_math is set, or if GCC's software emulation
1435 is unable to accurately represent the result. */
1445 }
1448 {
1449 FIXED_VALUE_TYPE f1;
1450 FIXED_VALUE_TYPE f2;
1451 FIXED_VALUE_TYPE result;
1456 /* The following codes are handled by fixed_arithmetic. */
1458 {
1470 {
1477 }
1482 }
1489 /* Propagate overflow flags. */
1493 }
1496 {
1505 {
1516 mpc_mul);
1530 mpc_div);
1531 /* Fallthru. */
1537 {
1538 /* Keep this algorithm in sync with
1539 tree-complex.cc:expand_complex_div_straight().
1541 Expand complex division to scalars, straightforward algorithm.
1542 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1543 t = br*br + bi*bi
1544 */
1545 tree magsquared
1549 tree t1
1553 tree t2
1560 }
1561 else
1562 {
1563 /* Keep this algorithm in sync with
1564 tree-complex.cc:expand_complex_div_wide().
1566 Expand complex division to scalars, modified algorithm to minimize
1567 overflow with wide input ranges. */
1573 {
1574 /* In the TRUE branch, we compute
1575 ratio = br/bi;
1576 div = (br * ratio) + bi;
1577 tr = (ar * ratio) + ai;
1578 ti = (ai * ratio) - ar;
1579 tr = tr / div;
1580 ti = ti / div; */
1591 }
1592 else
1593 {
1594 /* In the FALSE branch, we compute
1595 ratio = d/c;
1596 divisor = (d * ratio) + c;
1597 tr = (b * ratio) + a;
1598 ti = b - (a * ratio);
1599 tr = tr / div;
1600 ti = ti / div; */
1612 }
1613 }
1618 }
1622 }
1628 {
1633 /* We can operate directly on the encoding if:
1635 a3 - a2 == a2 - a1 && b3 - b2 == b2 - b1
1636 implies
1637 (a3 op b3) - (a2 op b2) == (a2 op b2) - (a1 op b1)
1639 Addition and subtraction are the supported operators
1640 for which this is true. */
1643 /* We can operate directly on stepped encodings if:
1645 a3 - a2 == a2 - a1
1646 implies:
1647 (a3 op c) - (a2 op c) == (a2 op c) - (a1 op c)
1649 which is true if (x -> x op c) distributes over addition. */
1651 else
1652 /* Similarly in reverse. */
1654 tree_vector_builder elts;
1659 {
1665 /* It is possible that const_binop cannot handle the given
1666 code and return NULL_TREE */
1670 }
1673 }
1675 /* Shifts allow a scalar offset for a vector. */
1678 {
1681 tree_vector_builder elts;
1686 {
1691 /* It is possible that const_binop cannot handle the given
1692 code and return NULL_TREE. */
1696 }
1699 }
1701 }
1703 /* Overload that adds a TYPE parameter to be able to dispatch
1704 to fold_relational_const. */
1706 tree
1708 {
1712 /* ??? Until we make the const_binop worker take the type of the
1713 result as argument put those cases that need it here. */
1715 {
1732 {
1737 }
1743 {
1759 {
1764 ? NOP_EXPR
1771 }
1774 }
1780 {
1803 {
1816 }
1819 }
1822 }
1827 /* Make sure type and arg0 have the same saturating flag. */
1832 }
1834 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1835 Return zero if computing the constants is not possible. */
1837 tree
1839 {
1840 /* Don't perform the operation, other than NEGATE and ABS, if
1841 flag_signaling_nans is on and the operand is a signaling NaN. */
1851 {
1852 CASE_CONVERT:
1859 /* If the source address is 0, and the source address space
1860 cannot have a valid object at 0, fold to dest type null. */
1871 {
1872 /* Can't call fold_negate_const directly here as that doesn't
1873 handle all cases and we might not be able to negate some
1874 constants. */
1879 }
1889 {
1893 }
1901 /* Perform BIT_NOT_EXPR on each element individually. */
1903 {
1904 tree elem;
1906 /* This can cope with stepped encodings because ~x == -1 - x. */
1907 tree_vector_builder elements;
1911 {
1917 }
1920 }
1944 {
1967 else
1972 {
1978 }
1981 }
1990 }
1993 }
1995 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1996 indicates which particular sizetype to create. */
1998 tree
2000 {
2002 }
2003 \f
2004 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
2005 is a tree code. The type of the result is taken from the operands.
2006 Both must be equivalent integer types, ala int_binop_types_match_p.
2007 If the operands are constant, so is the result. */
2009 tree
2011 {
2020 /* Handle the special case of two poly_int constants faster. */
2022 {
2023 /* And some specific cases even faster than that. */
2025 {
2032 }
2034 {
2038 }
2040 {
2044 }
2046 /* Handle general case of two integer constants. For sizetype
2047 constant calculations we always want to know about overflow,
2048 even in the unsigned case. */
2052 }
2055 }
2057 /* Given two values, either both of sizetype or both of bitsizetype,
2058 compute the difference between the two values. Return the value
2059 in signed type corresponding to the type of the operands. */
2061 tree
2063 {
2065 tree ctype;
2070 /* If the type is already signed, just do the simple thing. */
2078 else
2081 /* If either operand is not a constant, do the conversions to the signed
2082 type and subtract. The hardware will do the right thing with any
2083 overflow in the subtraction. */
2089 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
2090 Otherwise, subtract the other way, convert to CTYPE (we know that can't
2091 overflow) and negate (which can't either). Special-case a result
2092 of zero while we're here. */
2098 else
2102 MINUS_EXPR,
2104 }
2105 \f
2106 /* A subroutine of fold_convert_const handling conversions of an
2107 INTEGER_CST to another integer type. */
2109 static tree
2111 {
2112 /* Given an integer constant, make new constant with new type,
2113 appropriately sign-extended or truncated. Use widest_int
2114 so that any extension is done according ARG1's type. */
2118 }
2120 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2121 to an integer type. */
2123 static tree
2125 {
2127 tree t;
2129 /* The following code implements the floating point to integer
2130 conversion rules required by the Java Language Specification,
2131 that IEEE NaNs are mapped to zero and values that overflow
2132 the target precision saturate, i.e. values greater than
2133 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
2134 are mapped to INT_MIN. These semantics are allowed by the
2135 C and C++ standards that simply state that the behavior of
2136 FP-to-integer conversion is unspecified upon overflow. */
2138 wide_int val;
2139 REAL_VALUE_TYPE r;
2143 {
2150 }
2152 /* If R is NaN, return zero and show we have an overflow. */
2154 {
2157 }
2159 /* See if R is less than the lower bound or greater than the
2160 upper bound. */
2163 {
2167 {
2170 }
2171 }
2174 {
2177 {
2180 {
2183 }
2184 }
2185 }
2192 }
2194 /* A subroutine of fold_convert_const handling conversions of a
2195 FIXED_CST to an integer type. */
2197 static tree
2199 {
2200 tree t;
2202 scalar_mode mode;
2204 /* Right shift FIXED_CST to temp by fbit. */
2208 {
2210 HOST_BITS_PER_DOUBLE_INT,
2213 /* Left shift temp to temp_trunc by fbit. */
2215 HOST_BITS_PER_DOUBLE_INT,
2217 }
2218 else
2219 {
2222 }
2224 /* If FIXED_CST is negative, we need to round the value toward 0.
2225 By checking if the fractional bits are not zero to add 1 to temp. */
2231 /* Given a fixed-point constant, make new constant with new type,
2232 appropriately sign-extended or truncated. */
2240 }
2242 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2243 to another floating point type. */
2245 static tree
2247 {
2248 REAL_VALUE_TYPE value;
2249 tree t;
2251 /* If the underlying modes are the same, simply treat it as
2252 copy and rebuild with TREE_REAL_CST information and the
2253 given type. */
2255 {
2258 }
2260 /* Don't perform the operation if flag_signaling_nans is on
2261 and the operand is a signaling NaN. */
2266 /* With flag_rounding_math we should respect the current rounding mode
2267 unless the conversion is exact. */
2275 /* If converting an infinity or NAN to a representation that doesn't
2276 have one, set the overflow bit so that we can produce some kind of
2277 error message at the appropriate point if necessary. It's not the
2278 most user-friendly message, but it's better than nothing. */
2285 /* Regular overflow, conversion produced an infinity in a mode that
2286 can't represent them. */
2291 else
2294 }
2296 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2297 to a floating point type. */
2299 static tree
2301 {
2302 REAL_VALUE_TYPE value;
2303 tree t;
2311 }
2313 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2314 to another fixed-point type. */
2316 static tree
2318 {
2319 FIXED_VALUE_TYPE value;
2320 tree t;
2327 /* Propagate overflow flags. */
2331 }
2333 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2334 to a fixed-point type. */
2336 static tree
2338 {
2339 FIXED_VALUE_TYPE value;
2340 tree t;
2342 double_int di;
2349 else
2357 /* Propagate overflow flags. */
2361 }
2363 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2364 to a fixed-point type. */
2366 static tree
2368 {
2369 FIXED_VALUE_TYPE value;
2370 tree t;
2378 /* Propagate overflow flags. */
2382 }
2384 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2385 type TYPE. If no simplification can be done return NULL_TREE. */
2387 static tree
2389 {
2394 /* We can't widen types, since the runtime value could overflow the
2395 original type before being extended to the new type. */
2406 {
2413 }
2415 {
2417 {
2419 /* Avoid the folding if flag_rounding_math is on and the
2420 conversion is not exact. */
2422 {
2428 }
2430 }
2435 }
2437 {
2444 }
2446 {
2449 {
2452 /* We can't handle steps directly when extending, since the
2453 values need to wrap at the original precision first. */
2454 bool step_ok_p
2458 tree_vector_builder v;
2463 {
2469 }
2471 }
2472 }
2474 }
2476 /* Construct a vector of zero elements of vector type TYPE. */
2478 static tree
2480 {
2481 tree t;
2485 }
2487 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2489 bool
2491 {
2506 {
2528 }
2529 }
2531 /* Convert expression ARG to type TYPE. Used by the middle-end for
2532 simple conversions in preference to calling the front-end's convert. */
2534 tree
2536 {
2538 tree tem;
2549 {
2552 /* Handle conversions between pointers to different address spaces. */
2557 /* fall through */
2562 {
2566 }
2580 {
2584 }
2586 {
2590 }
2592 {
2596 }
2599 {
2617 }
2622 {
2626 }
2629 {
2643 }
2647 {
2656 integer_zero_node));
2658 {
2662 {
2668 }
2676 }
2680 }
2698 }
2699 fold_convert_exit:
2702 }
2703 \f
2704 /* Return false if expr can be assumed not to be an lvalue, true
2705 otherwise. */
2707 static bool
2709 {
2710 /* We only need to wrap lvalue tree codes. */
2712 {
2745 /* Assume the worst for front-end tree codes. */
2749 }
2752 }
2754 /* Return an expr equal to X but certainly not valid as an lvalue. */
2756 tree
2758 {
2759 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2760 us. */
2767 }
2768 \f
2769 /* Given a tree comparison code, return the code that is the logical inverse.
2770 It is generally not safe to do this for floating-point comparisons, except
2771 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2772 ERROR_MARK in this case. */
2774 enum tree_code
2776 {
2782 {
2813 }
2814 }
2816 /* Similar, but return the comparison that results if the operands are
2817 swapped. This is safe for floating-point. */
2819 enum tree_code
2821 {
2823 {
2849 }
2850 }
2853 /* Convert a comparison tree code from an enum tree_code representation
2854 into a compcode bit-based encoding. This function is the inverse of
2855 compcode_to_comparison. */
2857 static enum comparison_code
2859 {
2861 {
2892 }
2893 }
2895 /* Convert a compcode bit-based encoding of a comparison operator back
2896 to GCC's enum tree_code representation. This function is the
2897 inverse of comparison_to_compcode. */
2899 static enum tree_code
2901 {
2903 {
2934 }
2935 }
2937 /* Return true if COND1 tests the opposite condition of COND2. */
2939 bool
2941 {
2944 && (invert_tree_comparison
2951 }
2953 /* Return a tree for the comparison which is the combination of
2954 doing the AND or OR (depending on CODE) of the two operations LCODE
2955 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2956 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2957 if this makes the transformation invalid. */
2959 tree
2964 {
2971 {
2982 }
2985 {
2986 /* Eliminate unordered comparisons, as well as LTGT and ORD
2987 which are not used unless the mode has NaNs. */
2993 }
2995 {
2996 /* Check that the original operation and the optimized ones will trap
2997 under the same condition. */
3008 /* In a short-circuited boolean expression the LHS might be
3009 such that the RHS, if evaluated, will never trap. For
3010 example, in ORD (x, y) && (x < y), we evaluate the RHS only
3011 if neither x nor y is NaN. (This is a mixed blessing: for
3012 example, the expression above will never trap, hence
3013 optimizing it to x < y would be invalid). */
3018 /* If the comparison was short-circuited, and only the RHS
3019 trapped, we may now generate a spurious trap. */
3024 /* If we changed the conditions that cause a trap, we lose. */
3027 }
3033 else
3034 {
3039 }
3040 }
3041 \f
3042 /* Return nonzero if two operands (typically of the same tree node)
3043 are necessarily equal. FLAGS modifies behavior as follows:
3045 If OEP_ONLY_CONST is set, only return nonzero for constants.
3046 This function tests whether the operands are indistinguishable;
3047 it does not test whether they are equal using C's == operation.
3048 The distinction is important for IEEE floating point, because
3049 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
3050 (2) two NaNs may be indistinguishable, but NaN!=NaN.
3052 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
3053 even though it may hold multiple values during a function.
3054 This is because a GCC tree node guarantees that nothing else is
3055 executed between the evaluation of its "operands" (which may often
3056 be evaluated in arbitrary order). Hence if the operands themselves
3057 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
3058 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
3059 unset means assuming isochronic (or instantaneous) tree equivalence.
3060 Unless comparing arbitrary expression trees, such as from different
3061 statements, this flag can usually be left unset.
3063 If OEP_PURE_SAME is set, then pure functions with identical arguments
3064 are considered the same. It is used when the caller has other ways
3065 to ensure that global memory is unchanged in between.
3067 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
3068 not values of expressions.
3070 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
3071 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
3073 If OEP_BITWISE is set, then require the values to be bitwise identical
3074 rather than simply numerically equal. Do not take advantage of things
3075 like math-related flags or undefined behavior; only return true for
3076 values that are provably bitwise identical in all circumstances.
3078 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
3079 any operand with side effect. This is unnecesarily conservative in the
3080 case we know that arg0 and arg1 are in disjoint code paths (such as in
3081 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
3082 addresses with TREE_CONSTANT flag set so we know that &var == &var
3083 even if var is volatile. */
3085 bool
3088 {
3096 /* If either is ERROR_MARK, they aren't equal. */
3102 /* Similar, if either does not have a type (like a template id),
3103 they aren't equal. */
3107 /* Bitwise identity makes no sense if the values have different layouts. */
3112 /* We cannot consider pointers to different address space equal. */
3119 /* Check equality of integer constants before bailing out due to
3120 precision differences. */
3122 {
3123 /* Address of INTEGER_CST is not defined; check that we did not forget
3124 to drop the OEP_ADDRESS_OF flags. */
3127 }
3130 {
3131 /* If both types don't have the same signedness, then we can't consider
3132 them equal. We must check this before the STRIP_NOPS calls
3133 because they may change the signedness of the arguments. As pointers
3134 strictly don't have a signedness, require either two pointers or
3135 two non-pointers as well. */
3141 /* If both types don't have the same precision, then it is not safe
3142 to strip NOPs. */
3149 }
3150 #if 0
3151 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
3152 sanity check once the issue is solved. */
3153 else
3154 /* Addresses of conversions and SSA_NAMEs (and many other things)
3155 are not defined. Check that we did not forget to drop the
3156 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
3159 #endif
3161 /* In case both args are comparisons but with different comparison
3162 code, try to swap the comparison operands of one arg to produce
3163 a match and compare that variant. */
3167 {
3175 }
3178 {
3179 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
3181 ;
3183 {
3184 /* If we are interested in comparing addresses ignore
3185 MEM_REF wrappings of the base that can appear just for
3186 TBAA reasons. */
3200 }
3201 else
3203 }
3205 /* When not checking adddresses, this is needed for conversions and for
3206 COMPONENT_REF. Might as well play it safe and always test this. */
3213 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
3214 We don't care about side effects in that case because the SAVE_EXPR
3215 takes care of that for us. In all other cases, two expressions are
3216 equal if they have no side effects. If we have two identical
3217 expressions with side effects that should be treated the same due
3218 to the only side effects being identical SAVE_EXPR's, that will
3219 be detected in the recursive calls below.
3220 If we are taking an invariant address of two identical objects
3221 they are necessarily equal as well. */
3228 /* Next handle constant cases, those for which we can return 1 even
3229 if ONLY_CONST is set. */
3232 {
3245 {
3246 /* If we do not distinguish between signed and unsigned zero,
3247 consider them equal. */
3250 }
3254 {
3269 }
3273 flags)
3275 flags));
3286 flags | OEP_ADDRESS_OF
3289 /* In GIMPLE empty constructors are allowed in initializers of
3290 aggregates. */
3294 }
3296 /* Don't handle more cases for OEP_BITWISE, since we can't guarantee that
3297 two instances of undefined behavior will give identical results. */
3301 /* Define macros to test an operand from arg0 and arg1 for equality and a
3302 variant that allows null and views null as being different from any
3303 non-null value. In the latter case, if either is null, the both
3304 must be; otherwise, do the normal comparison. */
3305 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
3306 TREE_OPERAND (arg1, N), flags)
3308 #define OP_SAME_WITH_NULL(N) \
3309 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
3310 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
3313 {
3315 /* Two conversions are equal only if signedness and modes match. */
3317 {
3318 CASE_CONVERT:
3326 }
3336 /* For commutative ops, allow the other order. */
3344 /* If either of the pointer (or reference) expressions we are
3345 dereferencing contain a side effect, these cannot be equal,
3346 but their addresses can be. */
3353 {
3356 {
3360 /* Verify that the access types are compatible. */
3364 }
3369 /* Require the same offset. */
3375 /* Fallthru. */
3383 {
3384 /* Require equal access sizes */
3390 flags)))
3392 /* Verify that access happens in similar types. */
3395 /* Verify that accesses are TBAA compatible. */
3404 /* Verify that alignment is compatible. */
3408 }
3411 /* TARGET_MEM_REF require equal extra operands. */
3422 /* Compare the array index by value if it is constant first as we
3423 may have different types but same value here. */
3429 /* Compare low bound and element size as with OEP_ADDRESS_OF
3430 we have to account for the offset of the ref. */
3435 array_ref_low_bound
3439 array_ref_element_size
3441 flags))));
3444 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3445 may be NULL when we're called to compare MEM_EXPRs. */
3448 {
3451 /* Most of time we only need to compare FIELD_DECLs for equality.
3452 However when determining address look into actual offsets.
3453 These may match for unions and unshared record types. */
3456 {
3459 {
3463 /* Non-FIELD_DECL operands can appear in C++ templates. */
3470 flags))
3472 }
3473 else
3475 }
3476 }
3487 }
3491 {
3493 /* Be sure we pass right ADDRESS_OF flag. */
3510 /* The multiplcation operands are commutative. */
3511 /* FALLTHRU */
3519 /* Otherwise take into account this is a commutative operation. */
3532 /* BIT_INSERT_EXPR has an implict operand as the type precision
3533 of op1. Need to check to make sure they are the same. */
3539 /* FALLTHRU */
3564 /* Virtual table reference. */
3576 {
3581 }
3586 }
3590 {
3594 /* If not both CALL_EXPRs are either internal or normal function
3595 functions, then they are not equal. */
3598 {
3599 /* If the CALL_EXPRs call different internal functions, then they
3600 are not equal. */
3603 }
3604 else
3605 {
3606 /* If the CALL_EXPRs call different functions, then they are not
3607 equal. */
3609 flags))
3611 }
3613 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3614 {
3618 else
3622 }
3624 /* Now see if all the arguments are the same. */
3625 {
3636 /* If we get here and both argument lists are exhausted
3637 then the CALL_EXPRs are equal. */
3639 }
3642 }
3645 /* Consider __builtin_sqrt equal to sqrt. */
3655 {
3656 /* Consider decls with the same name equal. The caller needs
3657 to make sure they refer to the same entity (such as a function
3658 formal parameter). */
3664 }
3669 {
3673 /* In GIMPLE constructors are used only to build vectors from
3674 elements. Individual elements in the constructor must be
3675 indexed in increasing order and form an initial sequence.
3677 We make no effort to compare constructors in generic.
3678 (see sem_variable::equals in ipa-icf which can do so for
3679 constants). */
3684 /* Be sure that vectors constructed have the same representation.
3685 We only tested element precision and modes to match.
3686 Vectors may be BLKmode and thus also check that the number of
3687 parts match. */
3700 {
3705 /* In GIMPLE the indexes can be either NULL or matching i.
3706 Double check this so we won't get false
3707 positives for GENERIC. */
3715 }
3717 }
3720 {
3721 /* Compare the STATEMENT_LISTs. */
3727 {
3728 /* The lists don't have the same number of statements. */
3734 flags & (OEP_LEXICOGRAPHIC
3737 }
3738 }
3743 {
3754 }
3758 }
3760 #undef OP_SAME
3761 #undef OP_SAME_WITH_NULL
3762 }
3764 /* Generate a hash value for an expression. This can be used iteratively
3765 by passing a previous result as the HSTATE argument. */
3767 void
3770 {
3776 {
3779 }
3789 {
3790 /* Alas, constants aren't shared, so we can't rely on pointer
3791 identity. */
3801 {
3805 else
3809 }
3811 {
3815 }
3825 {
3832 }
3834 /* We can just compare by pointer. */
3838 /* The node itself doesn't matter. */
3842 /* Ignore. */
3845 /* A list of expressions, for a CALL_EXPR or as the elements of a
3846 VECTOR_CST. */
3851 {
3857 {
3858 /* In GIMPLE the indexes can be either NULL or matching i. */
3863 }
3865 }
3867 {
3868 tree_stmt_iterator i;
3873 }
3882 /* When referring to a built-in FUNCTION_DECL, use the __builtin__ form.
3883 Otherwise nodes that compare equal according to operand_equal_p might
3884 get different hash codes. However, don't do this for machine specific
3885 or front end builtins, since the function code is overloaded in those
3886 cases. */
3889 {
3892 }
3893 /* FALL THROUGH */
3896 {
3900 }
3904 {
3905 /* DECL's have a unique ID */
3907 }
3909 {
3910 /* For comparisons that can be swapped, use the lower
3911 tree code. */
3918 }
3920 {
3921 /* NOP_EXPR and CONVERT_EXPR are considered equal by
3922 operand_equal_p. */
3926 /* Don't hash the type, that can lead to having nodes which
3927 compare equal according to operand_equal_p, but which
3928 have different hash codes. Make sure to include signedness
3929 in the hash computation. */
3932 }
3933 /* For OEP_ADDRESS_OF, hash MEM_EXPR[&decl, 0] the same as decl. */
3941 /* Don't ICE on FE specific trees, or their arguments etc.
3942 during operand_equal_p hash verification. */
3945 else
3946 {
3952 {
3968 {
3975 }
3989 {
3990 /* The multiplication operands are commutative. */
3997 }
4005 /* For TARGET_EXPR, just hash on the TARGET_EXPR_SLOT.
4006 Usually different TARGET_EXPRs just should use
4007 different temporaries in their slots. */
4012 /* Virtual table reference. */
4020 {
4022 /* We compute mangled names only when free_lang_data is run.
4023 In that case we can hash precisely. */
4026 hstate.add_object
4027 (IDENTIFIER_HASH_VALUE
4029 }
4033 }
4035 /* Don't hash the type, that can lead to having nodes which
4036 compare equal according to operand_equal_p, but which
4037 have different hash codes. */
4039 {
4040 /* Make sure to include signness in the hash computation. */
4043 }
4046 {
4047 /* It's a commutative expression. We want to hash it the same
4048 however it appears. We do this by first hashing both operands
4049 and then rehashing based on the order of their independent
4050 hashes. */
4055 }
4056 else
4060 }
4062 }
4063 }
4065 bool
4068 {
4069 /* When checking and unless comparing DECL names, verify that if
4070 the outermost operand_equal_p call returns non-zero then ARG0
4071 and ARG1 have the same hash value. */
4073 {
4075 {
4077 {
4084 }
4086 }
4087 else
4091 }
4094 }
4099 /* Conveinece wrapper around operand_compare class because usually we do
4100 not need to play with the valueizer. */
4102 bool
4104 {
4106 }
4108 namespace inchash
4109 {
4111 /* Generate a hash value for an expression. This can be used iteratively
4112 by passing a previous result as the HSTATE argument.
4114 This function is intended to produce the same hash for expressions which
4115 would compare equal using operand_equal_p. */
4116 void
4118 {
4120 }
4122 }
4123 \f
4124 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
4125 with a different signedness or a narrower precision. */
4127 static bool
4129 {
4137 /* Discard any conversions that don't change the modes of ARG0 and ARG1
4138 and see if the inner values are the same. This removes any
4139 signedness comparison, which doesn't matter here. */
4147 /* Discard a single widening conversion from ARG1 and see if the inner
4148 value is the same as ARG0. */
4157 }
4158 \f
4159 /* See if ARG is an expression that is either a comparison or is performing
4160 arithmetic on comparisons. The comparisons must only be comparing
4161 two different values, which will be stored in *CVAL1 and *CVAL2; if
4162 they are nonzero it means that some operands have already been found.
4163 No variables may be used anywhere else in the expression except in the
4164 comparisons.
4166 If this is true, return 1. Otherwise, return zero. */
4168 static bool
4170 {
4174 /* We can handle some of the tcc_expression cases here. */
4183 {
4202 /* First see if we can handle the first operand, then the second. For
4203 the second operand, we know *CVAL1 can't be zero. It must be that
4204 one side of the comparison is each of the values; test for the
4205 case where this isn't true by failing if the two operands
4206 are the same. */
4215 ;
4219 ;
4220 else
4224 ;
4228 ;
4229 else
4236 }
4237 }
4238 \f
4239 /* ARG is a tree that is known to contain just arithmetic operations and
4240 comparisons. Evaluate the operations in the tree substituting NEW0 for
4241 any occurrence of OLD0 as an operand of a comparison and likewise for
4242 NEW1 and OLD1. */
4244 static tree
4247 {
4252 /* We can handle some of the tcc_expression cases here. */
4260 {
4275 {
4294 }
4295 /* Fall through - ??? */
4298 {
4302 /* We need to check both for exact equality and tree equality. The
4303 former will be true if the operand has a side-effect. In that
4304 case, we know the operand occurred exactly once. */
4317 }
4321 }
4322 }
4323 \f
4324 /* Return a tree for the case when the result of an expression is RESULT
4325 converted to TYPE and OMITTED was previously an operand of the expression
4326 but is now not needed (e.g., we folded OMITTED * 0).
4328 If OMITTED has side effects, we must evaluate it. Otherwise, just do
4329 the conversion of RESULT to TYPE. */
4331 tree
4333 {
4336 /* If the resulting operand is an empty statement, just return the omitted
4337 statement casted to void. */
4347 }
4349 /* Return a tree for the case when the result of an expression is RESULT
4350 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
4351 of the expression but are now not needed.
4353 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
4354 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
4355 evaluated before OMITTED2. Otherwise, if neither has side effects,
4356 just do the conversion of RESULT to TYPE. */
4358 tree
4361 {
4370 }
4372 \f
4373 /* Return a simplified tree node for the truth-negation of ARG. This
4374 never alters ARG itself. We assume that ARG is an operation that
4375 returns a truth value (0 or 1).
4377 FIXME: one would think we would fold the result, but it causes
4378 problems with the dominator optimizer. */
4380 static tree
4382 {
4387 /* If this is a comparison, we can simply invert it, except for
4388 floating-point non-equality comparisons, in which case we just
4389 enclose a TRUTH_NOT_EXPR around what we have. */
4392 {
4395 && flag_trapping_math
4408 }
4411 {
4430 /* Here we can invert either operand. We invert the first operand
4431 unless the second operand is a TRUTH_NOT_EXPR in which case our
4432 result is the XOR of the first operand with the inside of the
4433 negation of the second operand. */
4438 else
4461 {
4468 /* A COND_EXPR may have a throw as one operand, which
4469 then has void type. Just leave void operands
4470 as they are. */
4476 }
4488 CASE_CONVERT:
4492 /* fall through */
4514 }
4515 }
4517 /* Fold the truth-negation of ARG. This never alters ARG itself. We
4518 assume that ARG is an operation that returns a truth value (0 or 1
4519 for scalars, 0 or -1 for vectors). Return the folded expression if
4520 folding is successful. Otherwise, return NULL_TREE. */
4522 static tree
4524 {
4527 ? BIT_NOT_EXPR
4530 }
4532 /* Return a simplified tree node for the truth-negation of ARG. This
4533 never alters ARG itself. We assume that ARG is an operation that
4534 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
4536 tree
4538 {
4544 ? BIT_NOT_EXPR
4547 }
4548 \f
4549 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
4550 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
4551 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
4552 is the original memory reference used to preserve the alias set of
4553 the access. */
4555 static tree
4559 {
4562 /* Attempt not to lose the access path if possible. */
4564 {
4566 machine_mode nmode;
4568 tree noffset;
4576 && !reversep
4577 && !nreversep
4579 {
4582 }
4583 }
4592 {
4599 }
4614 }
4616 /* Optimize a bit-field compare.
4618 There are two cases: First is a compare against a constant and the
4619 second is a comparison of two items where the fields are at the same
4620 bit position relative to the start of a chunk (byte, halfword, word)
4621 large enough to contain it. In these cases we can avoid the shift
4622 implicit in bitfield extractions.
4624 For constants, we emit a compare of the shifted constant with the
4625 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
4626 compared. For two fields at the same position, we do the ANDs with the
4627 similar mask and compare the result of the ANDs.
4629 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
4630 COMPARE_TYPE is the type of the comparison, and LHS and RHS
4631 are the left and right operands of the comparison, respectively.
4633 If the optimization described above can be done, we return the resulting
4634 tree. Otherwise we return zero. */
4636 static tree
4639 {
4643 tree unsigned_type;
4646 scalar_int_mode nmode;
4651 tree mask;
4652 tree offset;
4654 /* Get all the information about the extractions being done. If the bit size
4655 is the same as the size of the underlying object, we aren't doing an
4656 extraction at all and so can do nothing. We also don't want to
4657 do anything if the inner expression is a PLACEHOLDER_EXPR since we
4658 then will no longer be able to replace it. */
4673 else
4674 {
4675 /* If this is not a constant, we can only do something if bit positions,
4676 sizes, signedness and storage order are the same. */
4677 rinner
4690 }
4692 /* Honor the C++ memory model and mimic what RTL expansion does. */
4696 {
4700 }
4702 /* See if we can find a mode to refer to this field. We should be able to,
4703 but fail if we can't. */
4711 /* Set signed and unsigned types of the precision of this mode for the
4712 shifts below. */
4715 /* Compute the bit position and size for the new reference and our offset
4716 within it. If the new reference is the same size as the original, we
4717 won't optimize anything, so return zero. */
4727 /* Make the mask to be used against the extracted field. */
4734 {
4738 /* If not comparing with constant, just rework the comparison
4739 and return. */
4747 }
4749 /* Otherwise, we are handling the constant case. See if the constant is too
4750 big for the field. Warn and return a tree for 0 (false) if so. We do
4751 this not only for its own sake, but to avoid having to test for this
4752 error case below. If we didn't, we might generate wrong code.
4754 For unsigned fields, the constant shifted right by the field length should
4755 be all zero. For signed fields, the high-order bits should agree with
4756 the sign bit. */
4759 {
4761 {
4765 }
4766 }
4767 else
4768 {
4771 {
4775 }
4776 }
4781 /* Single-bit compares should always be against zero. */
4783 {
4786 }
4788 /* Make a new bitfield reference, shift the constant over the
4789 appropriate number of bits and mask it with the computed mask
4790 (in case this was a signed field). If we changed it, make a new one. */
4798 mask);
4803 }
4804 \f
4805 /* Subroutine for fold_truth_andor_1: decode a field reference.
4807 If EXP is a comparison reference, we return the innermost reference.
4809 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4810 set to the starting bit number.
4812 If the innermost field can be completely contained in a mode-sized
4813 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4815 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4816 otherwise it is not changed.
4818 *PUNSIGNEDP is set to the signedness of the field.
4820 *PREVERSEP is set to the storage order of the field.
4822 *PMASK is set to the mask used. This is either contained in a
4823 BIT_AND_EXPR or derived from the width of the field.
4825 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4827 Return 0 if this is not a component reference or is one that we can't
4828 do anything with. */
4830 static tree
4835 {
4840 tree unsigned_type;
4843 /* All the optimizations using this function assume integer fields.
4844 There are problems with FP fields since the type_for_size call
4845 below can fail for, e.g., XFmode. */
4849 /* We are interested in the bare arrangement of bits, so strip everything
4850 that doesn't affect the machine mode. However, record the type of the
4851 outermost expression if it may matter below. */
4858 {
4864 }
4875 /* Reject out-of-bound accesses (PR79731). */
4887 /* If the number of bits in the reference is the same as the bitsize of
4888 the outer type, then the outer type gives the signedness. Otherwise
4889 (in case of a small bitfield) the signedness is unchanged. */
4893 /* Compute the mask to access the bitfield. */
4901 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4909 }
4911 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4912 bit positions and MASK is SIGNED. */
4914 static bool
4916 {
4920 /* If this function returns true when the type of the mask is
4921 UNSIGNED, then there will be errors. In particular see
4922 gcc.c-torture/execute/990326-1.c. There does not appear to be
4923 any documentation paper trail as to why this is so. But the pre
4924 wide-int worked with that restriction and it has been preserved
4925 here. */
4930 }
4932 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4933 represents the sign bit of EXP's type. If EXP represents a sign
4934 or zero extension, also test VAL against the unextended type.
4935 The return value is the (sub)expression whose sign bit is VAL,
4936 or NULL_TREE otherwise. */
4938 tree
4940 {
4942 tree t;
4944 /* Tree EXP must have an integral type. */
4949 /* Tree VAL must be an integer constant. */
4958 /* Handle extension from a narrower type. */
4964 }
4966 /* Subroutine for fold_truth_andor_1 and simple_condition_p: determine if an
4967 operand is simple enough to be evaluated unconditionally. */
4969 static bool
4971 {
4972 /* Strip any conversions that don't change the machine mode. */
4981 /* Don't regard global variables as simple. They may be
4982 allocated in ways unknown to the compiler (shared memory,
4983 #pragma weak, etc). */
4986 /* Weakrefs are not safe to be read, since they can be NULL.
4987 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4988 have DECL_WEAK flag set. */
4990 /* Loading a static variable is unduly expensive, but global
4991 registers aren't expensive. */
4993 }
4995 /* Determine if an operand is simple enough to be evaluated unconditionally.
4996 In addition to simple_operand_p, we assume that comparisons, conversions,
4997 and logic-not operations are simple, if their operands are simple, too. */
4999 bool
5001 {
5020 }
5022 \f
5023 /* The following functions are subroutines to fold_range_test and allow it to
5024 try to change a logical combination of comparisons into a range test.
5026 For example, both
5027 X == 2 || X == 3 || X == 4 || X == 5
5028 and
5029 X >= 2 && X <= 5
5030 are converted to
5031 (unsigned) (X - 2) <= 3
5033 We describe each set of comparisons as being either inside or outside
5034 a range, using a variable named like IN_P, and then describe the
5035 range with a lower and upper bound. If one of the bounds is omitted,
5036 it represents either the highest or lowest value of the type.
5038 In the comments below, we represent a range by two numbers in brackets
5039 preceded by a "+" to designate being inside that range, or a "-" to
5040 designate being outside that range, so the condition can be inverted by
5041 flipping the prefix. An omitted bound is represented by a "-". For
5042 example, "- [-, 10]" means being outside the range starting at the lowest
5043 possible value and ending at 10, in other words, being greater than 10.
5044 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
5045 always false.
5047 We set up things so that the missing bounds are handled in a consistent
5048 manner so neither a missing bound nor "true" and "false" need to be
5049 handled using a special case. */
5051 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
5052 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
5053 and UPPER1_P are nonzero if the respective argument is an upper bound
5054 and zero for a lower. TYPE, if nonzero, is the type of the result; it
5055 must be specified for a comparison. ARG1 will be converted to ARG0's
5056 type if both are specified. */
5058 static tree
5061 {
5062 tree tem;
5066 /* If neither arg represents infinity, do the normal operation.
5067 Else, if not a comparison, return infinity. Else handle the special
5068 comparison rules. Note that most of the cases below won't occur, but
5069 are handled for consistency. */
5072 {
5077 }
5082 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
5083 for neither. In real maths, we cannot assume open ended ranges are
5084 the same. But, this is computer arithmetic, where numbers are finite.
5085 We can therefore make the transformation of any unbounded range with
5086 the value Z, Z being greater than any representable number. This permits
5087 us to treat unbounded ranges as equal. */
5091 {
5112 }
5115 }
5116 \f
5117 /* Helper routine for make_range. Perform one step for it, return
5118 new expression if the loop should continue or NULL_TREE if it should
5119 stop. */
5121 tree
5125 {
5131 {
5133 /* We can only do something if the range is testing for zero. */
5142 /* We can only do something if the range is testing for zero
5143 and if the second operand is an integer constant. Note that
5144 saying something is "in" the range we make is done by
5145 complementing IN_P since it will set in the initial case of
5146 being not equal to zero; "out" is leaving it alone. */
5153 {
5174 }
5176 /* If this is an unsigned comparison, we also know that EXP is
5177 greater than or equal to zero. We base the range tests we make
5178 on that fact, so we record it here so we can parse existing
5179 range tests. We test arg0_type since often the return type
5180 of, e.g. EQ_EXPR, is boolean. */
5182 {
5186 NULL_TREE))
5191 /* If the high bound is missing, but we have a nonzero low
5192 bound, reverse the range so it goes from zero to the low bound
5193 minus 1. */
5195 {
5200 }
5201 }
5209 /* If flag_wrapv and ARG0_TYPE is signed, make sure
5210 low and high are non-NULL, then normalize will DTRT. */
5213 {
5218 }
5220 /* (-x) IN [a,b] -> x in [-b, -a] */
5232 /* ~ X -> -X - 1 */
5241 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
5242 move a constant to the other side. */
5247 /* If EXP is signed, any overflow in the computation is undefined,
5248 so we don't worry about it so long as our computations on
5249 the bounds don't overflow. For unsigned, overflow is defined
5250 and this is exactly the right thing. */
5262 normalize:
5263 /* Check for an unsigned range which has wrapped around the maximum
5264 value thus making n_high < n_low, and normalize it. */
5266 {
5272 /* If the range is of the form +/- [ x+1, x ], we won't
5273 be able to normalize it. But then, it represents the
5274 whole range or the empty set, so make it
5275 +/- [ -, - ]. */
5279 else
5281 }
5282 else
5290 CASE_CONVERT:
5308 /* If we're converting arg0 from an unsigned type, to exp,
5309 a signed type, we will be doing the comparison as unsigned.
5310 The tests above have already verified that LOW and HIGH
5311 are both positive.
5313 So we have to ensure that we will handle large unsigned
5314 values the same way that the current signed bounds treat
5315 negative values. */
5318 {
5319 tree high_positive;
5320 tree equiv_type;
5321 /* For fixed-point modes, we need to pass the saturating flag
5322 as the 2nd parameter. */
5324 equiv_type
5327 else
5328 equiv_type
5331 /* A range without an upper bound is, naturally, unbounded.
5332 Since convert would have cropped a very large value, use
5333 the max value for the destination type. */
5334 high_positive
5341 high_positive),
5344 /* If the low bound is specified, "and" the range with the
5345 range for which the original unsigned value will be
5346 positive. */
5348 {
5351 integer_zero_node),
5352 high_positive))
5356 }
5357 else
5358 {
5359 /* Otherwise, "or" the range with the range of the input
5360 that will be interpreted as negative. */
5363 integer_zero_node),
5364 high_positive))
5368 }
5369 }
5371 /* Otherwise, if we are converting arg0 from signed type, to exp,
5372 an unsigned type, we will do the comparison as signed. If
5373 high is non-NULL, we punt above if it doesn't fit in the signed
5374 type, so if we get through here, +[-, high] or +[low, high] are
5375 equivalent to +[-, n_high] or +[n_low, n_high]. Similarly,
5376 +[-, -] or -[-, -] are equivalent too. But if low is specified and
5377 high is not, the +[low, -] range is equivalent to union of
5378 +[n_low, -] and +[-, -1] ranges, so +[low, -] is equivalent to
5379 -[0, n_low-1] and similarly -[low, -] to +[0, n_low-1], except for
5380 low being 0, which should be treated as [-, -]. */
5383 && low
5385 {
5388 else
5389 {
5394 }
5395 }
5404 }
5405 }
5407 /* Given EXP, a logical expression, set the range it is testing into
5408 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
5409 actually being tested. *PLOW and *PHIGH will be made of the same
5410 type as the returned expression. If EXP is not a comparison, we
5411 will most likely not be returning a useful value and range. Set
5412 *STRICT_OVERFLOW_P to true if the return value is only valid
5413 because signed overflow is undefined; otherwise, do not change
5414 *STRICT_OVERFLOW_P. */
5416 tree
5419 {
5427 /* Start with simply saying "EXP != 0" and then look at the code of EXP
5428 and see if we can refine the range. Some of the cases below may not
5429 happen, but it doesn't seem worth worrying about this. We "continue"
5430 the outer loop when we've changed something; otherwise we "break"
5431 the switch, which will "break" the while. */
5437 {
5443 {
5451 }
5460 }
5462 /* If EXP is a constant, we can evaluate whether this is true or false. */
5464 {
5471 }
5475 }
5477 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
5478 a bitwise check i.e. when
5479 LOW == 0xXX...X00...0
5480 HIGH == 0xXX...X11...1
5481 Return corresponding mask in MASK and stem in VALUE. */
5483 static bool
5486 {
5509 }
5510 \f
5511 /* Helper routine for build_range_check and match.pd. Return the type to
5512 perform the check or NULL if it shouldn't be optimized. */
5514 tree
5516 {
5517 /* First make sure that arithmetics in this type is valid, then make sure
5518 that it wraps around. */
5523 {
5526 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
5527 for the type in question, as we rely on this here. */
5537 else
5539 }
5543 }
5545 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
5546 type, TYPE, return an expression to test if EXP is in (or out of, depending
5547 on IN_P) the range. Return 0 if the test couldn't be created. */
5549 tree
5552 {
5555 /* Disable this optimization for function pointer expressions
5556 on targets that require function pointer canonicalization. */
5563 {
5569 }
5591 value);
5594 {
5596 {
5600 }
5602 }
5604 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
5606 {
5610 {
5612 {
5615 etype
5617 else
5620 }
5623 }
5624 }
5626 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
5627 This requires wrap-around arithmetics for the type of the expression. */
5644 }
5645 \f
5646 /* Return the predecessor of VAL in its type, handling the infinite case. */
5648 static tree
5650 {
5656 else
5659 }
5661 /* Return the successor of VAL in its type, handling the infinite case. */
5663 static tree
5665 {
5671 else
5674 }
5676 /* Given two ranges, see if we can merge them into one. Return 1 if we
5677 can, 0 if we can't. Set the output range into the specified parameters. */
5679 bool
5682 {
5686 tree tem;
5696 /* Make range 0 be the range that starts first, or ends last if they
5697 start at the same value. Swap them if it isn't. */
5700 || (lowequal
5703 {
5707 }
5709 /* If the second range is != high1 where high1 is the type maximum of
5710 the type, try first merging with < high1 range. */
5712 && high1
5719 {
5724 /* Similarly for the second range != low1 where low1 is the type minimum
5725 of the type, try first merging with > low1 range. */
5730 }
5732 /* Now flag two cases, whether the ranges are disjoint or whether the
5733 second range is totally subsumed in the first. Note that the tests
5734 below are simplified by the ones above. */
5740 /* We now have four cases, depending on whether we are including or
5741 excluding the two ranges. */
5743 {
5744 /* If they don't overlap, the result is false. If the second range
5745 is a subset it is the result. Otherwise, the range is from the start
5746 of the second to the end of the first. */
5751 else
5753 }
5756 {
5757 /* If they don't overlap, the result is the first range. If they are
5758 equal, the result is false. If the second range is a subset of the
5759 first, and the ranges begin at the same place, we go from just after
5760 the end of the second range to the end of the first. If the second
5761 range is not a subset of the first, or if it is a subset and both
5762 ranges end at the same place, the range starts at the start of the
5763 first range and ends just before the second range.
5764 Otherwise, we can't describe this as a single range. */
5770 {
5775 {
5776 /* We are in the weird situation where high0 > high1 but
5777 high1 has no successor. Punt. */
5779 }
5780 }
5782 {
5787 {
5788 /* low0 < low1 but low1 has no predecessor. Punt. */
5790 }
5791 }
5792 else
5794 }
5797 {
5798 /* If they don't overlap, the result is the second range. If the second
5799 is a subset of the first, the result is false. Otherwise,
5800 the range starts just after the first range and ends at the
5801 end of the second. */
5806 else
5807 {
5812 {
5813 /* high1 > high0 but high0 has no successor. Punt. */
5815 }
5816 }
5817 }
5819 else
5820 {
5821 /* The case where we are excluding both ranges. Here the complex case
5822 is if they don't overlap. In that case, the only time we have a
5823 range is if they are adjacent. If the second is a subset of the
5824 first, the result is the first. Otherwise, the range to exclude
5825 starts at the beginning of the first range and ends at the end of the
5826 second. */
5828 {
5833 else
5834 {
5835 /* Canonicalize - [min, x] into - [-, x]. */
5838 {
5841 GET_MODE_BITSIZE
5844 /* FALLTHROUGH */
5857 }
5859 /* Canonicalize - [x, max] into - [x, -]. */
5862 {
5865 GET_MODE_BITSIZE
5868 /* FALLTHROUGH */
5884 }
5886 /* The ranges might be also adjacent between the maximum and
5887 minimum values of the given type. For
5888 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5889 return + [x + 1, y - 1]. */
5891 {
5898 }
5899 else
5901 }
5902 }
5905 else
5907 }
5911 }
5912 \f
5914 /* Subroutine of fold, looking inside expressions of the form
5915 A op B ? A : C, where (ARG00, COMP_CODE, ARG01), ARG1 and ARG2
5916 are the three operands of the COND_EXPR. This function is
5917 being used also to optimize A op B ? C : A, by reversing the
5918 comparison first.
5920 Return a folded expression whose code is not a COND_EXPR
5921 anymore, or NULL_TREE if no folding opportunity is found. */
5923 static tree
5927 {
5929 tree tem;
5934 /* If we have A op 0 ? A : -A, consider applying the following
5935 transformations:
5937 A == 0? A : -A same as -A
5938 A != 0? A : -A same as A
5939 A >= 0? A : -A same as abs (A)
5940 A > 0? A : -A same as abs (A)
5941 A <= 0? A : -A same as -abs (A)
5942 A < 0? A : -A same as -abs (A)
5944 None of these transformations work for modes with signed
5945 zeros. If A is +/-0, the first two transformations will
5946 change the sign of the result (from +0 to -0, or vice
5947 versa). The last four will fix the sign of the result,
5948 even though the original expressions could be positive or
5949 negative, depending on the sign of A.
5951 Note that all these transformations are correct if A is
5952 NaN, since the two alternatives (A and -A) are also NaNs. */
5959 /* In the case that A is of the form X-Y, '-A' (arg2) may
5960 have already been folded to Y-X, check for that. */
5968 {
5980 /* Fall through. */
5991 /* FALLTHRU */
5998 {
5999 /* A <= 0 ? A : -A for A INT_MIN is valid, but -abs(INT_MIN)
6000 is not, invokes UB both in abs and in the negation of it.
6001 So, use ABSU_EXPR instead. */
6006 }
6007 else
6008 {
6011 }
6015 }
6017 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
6018 A == 0 ? A : 0 is always 0 unless A is -0. Note that
6019 both transformations are correct when A is NaN: A != 0
6020 is then true, and A == 0 is false. */
6024 {
6029 }
6031 /* Try some transformations of A op B ? A : B.
6033 A == B? A : B same as B
6034 A != B? A : B same as A
6035 A >= B? A : B same as max (A, B)
6036 A > B? A : B same as max (B, A)
6037 A <= B? A : B same as min (A, B)
6038 A < B? A : B same as min (B, A)
6040 As above, these transformations don't work in the presence
6041 of signed zeros. For example, if A and B are zeros of
6042 opposite sign, the first two transformations will change
6043 the sign of the result. In the last four, the original
6044 expressions give different results for (A=+0, B=-0) and
6045 (A=-0, B=+0), but the transformed expressions do not.
6047 The first two transformations are correct if either A or B
6048 is a NaN. In the first transformation, the condition will
6049 be false, and B will indeed be chosen. In the case of the
6050 second transformation, the condition A != B will be true,
6051 and A will be chosen.
6053 The conversions to max() and min() are not correct if B is
6054 a number and A is not. The conditions in the original
6055 expressions will be false, so all four give B. The min()
6056 and max() versions would give a NaN instead. */
6059 /* Avoid these transformations if the COND_EXPR may be used
6060 as an lvalue in the C++ front-end. PR c++/19199. */
6061 && (in_gimple_form
6067 {
6073 {
6082 /* In C++ a ?: expression can be an lvalue, so put the
6083 operand which will be used if they are equal first
6084 so that we can convert this back to the
6085 corresponding COND_EXPR. */
6087 {
6095 }
6102 {
6110 }
6123 }
6124 }
6127 }
6130 \f
6131 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
6132 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
6133 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
6134 false) >= 2)
6135 #endif
6137 /* EXP is some logical combination of boolean tests. See if we can
6138 merge it into some range test. Return the new tree if so. */
6140 static tree
6143 {
6157 /* If op0 is known true or false and this is a short-circuiting
6158 operation we must not merge with op1 since that makes side-effects
6159 unconditional. So special-case this. */
6166 /* If this is an OR operation, invert both sides; we will invert
6167 again at the end. */
6171 /* If both expressions are the same, if we can merge the ranges, and we
6172 can build the range test, return it or it inverted. If one of the
6173 ranges is always true or always false, consider it to be the same
6174 expression as the other. */
6182 {
6186 }
6188 /* On machines where the branch cost is expensive, if this is a
6189 short-circuited branch and the underlying object on both sides
6190 is the same, make a non-short-circuit operation. */
6193 logical_op_non_short_circuit
6200 {
6201 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
6202 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
6203 which cases we can't do this. */
6211 {
6220 {
6223 WARN_STRICT_OVERFLOW_COMPARISON);
6227 }
6228 }
6229 }
6232 }
6233 \f
6234 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
6235 bit value. Arrange things so the extra bits will be set to zero if and
6236 only if C is signed-extended to its full width. If MASK is nonzero,
6237 it is an INTEGER_CST that should be AND'ed with the extra bits. */
6239 static tree
6241 {
6244 tree temp;
6249 /* We work by getting just the sign bit into the low-order bit, then
6250 into the high-order bit, then sign-extend. We then XOR that value
6251 with C. */
6255 /* We must use a signed type in order to get an arithmetic right shift.
6256 However, we must also avoid introducing accidental overflows, so that
6257 a subsequent call to integer_zerop will work. Hence we must
6258 do the type conversion here. At this point, the constant is either
6259 zero or one, and the conversion to a signed type can never overflow.
6260 We could get an overflow if this conversion is done anywhere else. */
6269 /* If necessary, convert the type back to match the type of C. */
6274 }
6275 \f
6276 /* For an expression that has the form
6277 (A && B) || ~B
6278 or
6279 (A || B) && ~B,
6280 we can drop one of the inner expressions and simplify to
6281 A || ~B
6282 or
6283 A && ~B
6284 LOC is the location of the resulting expression. OP is the inner
6285 logical operation; the left-hand side in the examples above, while CMPOP
6286 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
6287 removing a condition that guards another, as in
6288 (A != NULL && A->...) || A == NULL
6289 which we must not transform. If RHS_ONLY is true, only eliminate the
6290 right-most operand of the inner logical operation. */
6292 static tree
6295 {
6313 {
6316 {
6319 }
6320 }
6322 {
6325 {
6328 }
6329 }
6344 }
6346 /* Find ways of folding logical expressions of LHS and RHS:
6347 Try to merge two comparisons to the same innermost item.
6348 Look for range tests like "ch >= '0' && ch <= '9'".
6349 Look for combinations of simple terms on machines with expensive branches
6350 and evaluate the RHS unconditionally.
6352 For example, if we have p->a == 2 && p->b == 4 and we can make an
6353 object large enough to span both A and B, we can do this with a comparison
6354 against the object ANDed with the a mask.
6356 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
6357 operations to do this with one comparison.
6359 We check for both normal comparisons and the BIT_AND_EXPRs made this by
6360 function and the one above.
6362 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
6363 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
6365 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
6366 two operands.
6368 We return the simplified tree or 0 if no optimization is possible. */
6370 static tree
6373 {
6374 /* If this is the "or" of two comparisons, we can do something if
6375 the comparisons are NE_EXPR. If this is the "and", we can do something
6376 if the comparisons are EQ_EXPR. I.e.,
6377 (a->b == 2 && a->c == 4) can become (a->new == NEW).
6379 WANTED_CODE is this operation code. For single bit fields, we can
6380 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
6381 comparison for one-bit fields. */
6402 /* Start by getting the comparison codes. Fail if anything is volatile.
6403 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
6404 it were surrounded with a NE_EXPR. */
6413 {
6417 }
6420 {
6424 }
6435 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
6438 {
6441 {
6446 }
6449 {
6455 }
6456 }
6461 /* If the RHS can be evaluated unconditionally and its operands are
6462 simple, it wins to evaluate the RHS unconditionally on machines
6463 with expensive branches. In this case, this isn't a comparison
6464 that can be merged. */
6471 {
6472 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
6483 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
6493 }
6495 /* See if the comparisons can be merged. Then get all the parameters for
6496 each side. */
6521 /* It must be true that the inner operation on the lhs of each
6522 comparison must be the same if we are to be able to do anything.
6523 Then see if we have constants. If not, the same must be true for
6524 the rhs's. */
6533 {
6536 }
6541 else
6544 /* If either comparison code is not correct for our logical operation,
6545 fail. However, we can convert a one-bit comparison against zero into
6546 the opposite comparison against that bit being set in the field. */
6550 {
6552 {
6553 /* Make the left operand unsigned, since we are only interested
6554 in the value of one bit. Otherwise we are doing the wrong
6555 thing below. */
6558 }
6559 else
6561 }
6563 /* This is analogous to the code for l_const above. */
6565 {
6567 {
6570 }
6571 else
6573 }
6575 /* See if we can find a mode that contains both fields being compared on
6576 the left. If we can't, fail. Otherwise, update all constants and masks
6577 to be relative to a field of that size. */
6591 {
6594 }
6604 {
6613 {
6617 }
6618 }
6620 {
6629 {
6633 }
6634 }
6636 /* If the right sides are not constant, do the same for it. Also,
6637 disallow this optimization if a size, signedness or storage order
6638 mismatch occurs between the left and right sides. */
6640 {
6644 /* Make sure the two fields on the right
6645 correspond to the left without being swapped. */
6662 {
6665 }
6676 /* Make a mask that corresponds to both fields being compared.
6677 Do this for both items being compared. If the operands are the
6678 same size and the bits being compared are in the same position
6679 then we can do this by masking both and comparing the masked
6680 results. */
6687 {
6701 }
6703 /* There is still another way we can do something: If both pairs of
6704 fields being compared are adjacent, we may be able to make a wider
6705 field containing them both.
6707 Note that we still must mask the lhs/rhs expressions. Furthermore,
6708 the mask must be shifted to account for the shift done by
6709 make_bit_field_ref. */
6718 {
6719 tree type;
6737 /* Convert to the smaller type before masking out unwanted bits. */
6740 {
6742 {
6746 }
6748 {
6752 }
6753 }
6762 }
6765 }
6767 /* Handle the case of comparisons with constants. If there is something in
6768 common between the masks, those bits of the constants must be the same.
6769 If not, the condition is always false. Test for this to avoid generating
6770 incorrect code below. */
6775 {
6777 {
6780 }
6781 else
6782 {
6785 }
6786 }
6791 /* Construct the expression we will return. First get the component
6792 reference we will make. Unless the mask is all ones the width of
6793 that field, perform the mask operation. Then compare with the
6794 merged constant. */
6805 }
6806 \f
6807 /* T is an integer expression that is being multiplied, divided, or taken a
6808 modulus (CODE says which and what kind of divide or modulus) by a
6809 constant C. See if we can eliminate that operation by folding it with
6810 other operations already in T. WIDE_TYPE, if non-null, is a type that
6811 should be used for the computation if wider than our type.
6813 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
6814 (X * 2) + (Y * 4). We must, however, be assured that either the original
6815 expression would not overflow or that overflow is undefined for the type
6816 in the language in question.
6818 If we return a non-null expression, it is an equivalent form of the
6819 original computation, but need not be in the original type.
6821 We set *STRICT_OVERFLOW_P to true if the return values depends on
6822 signed overflow being undefined. Otherwise we do not change
6823 *STRICT_OVERFLOW_P. */
6825 static tree
6828 {
6829 /* To avoid exponential search depth, refuse to allow recursion past
6830 three levels. Beyond that (1) it's highly unlikely that we'll find
6831 something interesting and (2) we've probably processed it before
6832 when we built the inner expression. */
6835 tree ret;
6840 depth++;
6842 depth--;
6845 }
6847 static tree
6850 {
6862 /* Don't deal with constants of zero here; they confuse the code below. */
6872 /* Note that we need not handle conditional operations here since fold
6873 already handles those cases. So just do arithmetic here. */
6875 {
6877 /* For a constant, we can always simplify if we are a multiply
6878 or (for divide and modulus) if it is a multiple of our constant. */
6882 {
6885 /* If the multiplication overflowed, we lost information on it.
6886 See PR68142 and PR69845. */
6890 }
6896 /* If op0 is an expression ... */
6902 /* ... and has wrapping overflow, and its type is smaller
6903 than ctype, then we cannot pass through as widening. */
6907 /* ... or this is a truncation (t is narrower than op0),
6908 then we cannot pass through this narrowing. */
6911 /* ... or signedness changes for division or modulus,
6912 then we cannot pass through this conversion. */
6916 /* ... or has undefined overflow while the converted to
6917 type has not, we cannot do the operation in the inner type
6918 as that would introduce undefined overflow. */
6923 /* Pass the constant down and see if we can make a simplification. If
6924 we can, replace this expression with the inner simplification for
6925 possible later conversion to our or some other type. */
6936 /* If widening the type changes it from signed to unsigned, then we
6937 must avoid building ABS_EXPR itself as unsigned. */
6939 {
6943 {
6946 }
6948 }
6949 /* If the constant is negative, we cannot simplify this. */
6952 /* FALLTHROUGH */
6954 /* For division and modulus, type can't be unsigned, as e.g.
6955 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6956 For signed types, even with wrapping overflow, this is fine. */
6965 /* If widening the type changes the signedness, then we can't perform
6966 this optimization as that changes the result. */
6970 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6976 {
6983 }
6987 /* If the second operand is constant, this is a multiplication
6988 or floor division, by a power of two, so we can treat it that
6989 way unless the multiplier or divisor overflows. Signed
6990 left-shift overflow is implementation-defined rather than
6991 undefined in C90, so do not convert signed left shift into
6992 multiplication. */
6995 /* const_binop may not detect overflow correctly,
6996 so check for it explicitly here. */
7005 ctype,
7007 t1),
7012 /* See if we can eliminate the operation on both sides. If we can, we
7013 can return a new PLUS or MINUS. If we can't, the only remaining
7014 cases where we can do anything are if the second operand is a
7015 constant. */
7022 /* If not multiplication, we can only do this if both operands
7023 are divisible by c. */
7026 {
7031 }
7033 /* If this was a subtraction, negate OP1 and set it to be an addition.
7034 This simplifies the logic below. */
7036 {
7038 /* If OP1 was not easily negatable, the constant may be OP0. */
7040 {
7043 }
7044 }
7049 /* If either OP1 or C are negative, this optimization is not safe for
7050 some of the division and remainder types while for others we need
7051 to change the code. */
7053 {
7061 }
7063 /* If it's a multiply or a division/modulus operation of a multiple
7064 of our constant, do the operation and verify it doesn't overflow. */
7068 {
7071 /* We allow the constant to overflow with wrapping semantics. */
7075 }
7076 else
7079 /* If we have an unsigned type, we cannot widen the operation since it
7080 will change the result if the original computation overflowed. */
7084 /* The last case is if we are a multiply. In that case, we can
7085 apply the distributive law to commute the multiply and addition
7086 if the multiplication of the constants doesn't overflow
7087 and overflow is defined. With undefined overflow
7088 op0 * c might overflow, while (op0 + orig_op1) * c doesn't.
7089 But fold_plusminus_mult_expr would factor back any power-of-two
7090 value so do not distribute in the first place in this case. */
7098 op1);
7103 /* We have a special case here if we are doing something like
7104 (C * 8) % 4 since we know that's zero. */
7107 /* If the multiplication can overflow we cannot optimize this. */
7112 {
7115 }
7117 /* ... fall through ... */
7121 /* If we can extract our operation from the LHS, do so and return a
7122 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
7123 do something only if the second operand is a constant. */
7139 /* If these are the same operation types, we can associate them
7140 assuming no overflow. */
7142 {
7157 }
7159 /* If these operations "cancel" each other, we have the main
7160 optimizations of this pass, which occur when either constant is a
7161 multiple of the other, in which case we replace this with either an
7162 operation or CODE or TCODE.
7164 If we have an unsigned type, we cannot do this since it will change
7165 the result if the original computation overflowed. */
7173 {
7176 {
7182 }
7185 {
7191 }
7192 }
7197 }
7200 }
7201 \f
7202 /* Return a node which has the indicated constant VALUE (either 0 or
7203 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
7204 and is of the indicated TYPE. */
7206 tree
7208 {
7217 else
7219 }
7222 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
7223 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
7224 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
7225 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
7226 COND is the first argument to CODE; otherwise (as in the example
7227 given here), it is the second argument. TYPE is the type of the
7228 original expression. Return NULL_TREE if no simplification is
7229 possible. */
7231 static tree
7236 {
7244 /* Do not move possibly trapping operations into the conditional as this
7245 pessimizes code and causes gimplification issues when applied late. */
7253 {
7257 /* If this operand throws an expression, then it does not make
7258 sense to try to perform a logical or arithmetic operation
7259 involving it. */
7264 }
7267 {
7272 }
7273 else
7274 /* Detect the case of mixing vector and scalar types - bail out. */
7280 /* This transformation is only worthwhile if we don't have to wrap ARG
7281 in a SAVE_EXPR and the operation can be simplified without recursing
7282 on at least one of the branches once its pushed inside the COND_EXPR. */
7291 {
7295 else
7297 }
7299 {
7303 else
7305 }
7307 /* Check that we have simplified at least one of the branches. */
7312 }
7314 \f
7315 /* Subroutine of fold() that checks for the addition of ARG +/- 0.0.
7317 If !NEGATE, return true if ZERO_ARG is +/-0.0 and, for all ARG of
7318 type TYPE, ARG + ZERO_ARG is the same as ARG. If NEGATE, return true
7319 if ARG - ZERO_ARG is the same as X.
7321 If ARG is NULL, check for any value of type TYPE.
7323 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
7324 and finite. The problematic cases are when X is zero, and its mode
7325 has signed zeros. In the case of rounding towards -infinity,
7326 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
7327 modes, X + 0 is not the same as X because -0 + 0 is 0. */
7329 bool
7332 {
7336 /* Don't allow the fold with -fsignaling-nans. */
7340 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
7344 /* There is no case that is safe for all rounding modes. */
7348 /* In a vector or complex, we would need to check the sign of all zeros. */
7354 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
7358 /* The mode has signed zeros, and we have to honor their sign.
7359 In this situation, there are only two cases we can return true for.
7360 (i) X - 0 is the same as X with default rounding.
7361 (ii) X + 0 is X when X can't possibly be -0.0. */
7363 }
7365 /* Subroutine of match.pd that optimizes comparisons of a division by
7366 a nonzero integer constant against an integer constant, i.e.
7367 X/C1 op C2.
7369 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
7370 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
7372 enum tree_code
7375 {
7380 /* We have to do this the hard way to detect unsigned overflow.
7381 prod = int_const_binop (MULT_EXPR, c1, c2); */
7387 {
7391 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
7394 }
7396 {
7399 {
7418 }
7419 }
7420 else
7421 {
7422 /* A negative divisor reverses the relational operators. */
7427 {
7446 }
7447 }
7460 }
7462 /* Test whether it is preferable to swap two operands, ARG0 and
7463 ARG1, for example because ARG0 is an integer constant and ARG1
7464 isn't. */
7466 bool
7468 {
7482 /* It is preferable to swap two SSA_NAME to ensure a canonical form
7483 for commutative and comparison operators. Ensuring a canonical
7484 form allows the optimizers to find additional redundancies without
7485 having to explicitly check for both orderings. */
7491 /* Put SSA_NAMEs last. */
7497 /* Put variables last. */
7504 }
7507 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
7508 means A >= Y && A != MAX, but in this case we know that
7509 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
7511 static tree
7513 {
7520 else
7529 {
7532 }
7534 {
7537 }
7538 else
7545 {
7546 /* Convert the pointer types into integer before taking the difference. */
7550 }
7551 else
7558 }
7560 /* Fold a sum or difference of at least one multiplication.
7561 Returns the folded tree or NULL if no simplification could be made. */
7563 static tree
7566 {
7570 /* (A * C) +- (B * C) -> (A+-B) * C.
7571 (A * C) +- A -> A * (C+-1).
7572 We are most concerned about the case where C is a constant,
7573 but other combinations show up during loop reduction. Since
7574 it is not difficult, try all four possibilities. */
7577 {
7580 }
7582 {
7585 }
7586 else
7587 {
7588 /* We cannot generate constant 1 for fract. */
7593 }
7595 {
7598 }
7600 {
7602 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
7603 the purpose of this canonicalization. */
7607 {
7610 }
7611 else
7613 }
7614 else
7615 {
7616 /* We cannot generate constant 1 for fract. */
7621 }
7624 /* Prefer factoring a common non-constant. */
7634 /* No identical multiplicands; see if we can find a common
7635 power-of-two factor in non-power-of-two multiplies. This
7636 can help in multi-dimensional array access. */
7638 {
7641 HOST_WIDE_INT tmp;
7643 tree maybe_same;
7645 /* Move min of absolute values to int11. */
7647 {
7652 }
7653 else
7660 /* The remainder should not be a constant, otherwise we
7661 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
7662 increased the number of multiplications necessary. */
7664 {
7672 }
7673 }
7680 /* We are neither factoring zero nor minus one. */
7688 /* Same may be zero and thus the operation 'code' may overflow. Likewise
7689 same may be minus one and thus the multiplication may overflow. Perform
7690 the sum operation in an unsigned type. */
7695 /* If the sum evaluated to a constant that is not -INF the multiplication
7696 cannot overflow. */
7703 /* Do not resort to unsigned multiplication because
7704 we lose the no-overflow property of the expression. */
7706 }
7708 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
7709 specified by EXPR into the buffer PTR of length LEN bytes.
7710 Return the number of bytes placed in the buffer, or zero
7711 upon failure. */
7713 static int
7715 {
7727 /* Dry run. */
7733 {
7735 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
7736 number of bytes. */
7740 {
7747 else
7749 }
7750 else
7754 }
7756 }
7759 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7760 specified by EXPR into the buffer PTR of length LEN bytes.
7761 Return the number of bytes placed in the buffer, or zero
7762 upon failure. */
7764 static int
7766 {
7770 FIXED_VALUE_TYPE value;
7785 }
7788 /* Subroutine of native_encode_expr. Encode the REAL_CST
7789 specified by EXPR into the buffer PTR of length LEN bytes.
7790 Return the number of bytes placed in the buffer, or zero
7791 upon failure. */
7793 static int
7795 {
7801 /* There are always 32 bits in each long, no matter the size of
7802 the hosts long. We handle floating point representations with
7803 up to 192 bits. */
7812 /* Dry run. */
7821 {
7826 {
7833 else
7835 }
7836 else
7837 {
7840 {
7841 /* Reverse bytes within each long, or within the entire float
7842 if it's smaller than a long (for HFmode). */
7845 }
7846 }
7851 }
7853 }
7855 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7856 specified by EXPR into the buffer PTR of length LEN bytes.
7857 Return the number of bytes placed in the buffer, or zero
7858 upon failure. */
7860 static int
7862 {
7864 tree part;
7878 }
7880 /* Like native_encode_vector, but only encode the first COUNT elements.
7881 The other arguments are as for native_encode_vector. */
7883 static int
7886 {
7890 {
7891 /* This is the only case in which elements can be smaller than a byte.
7892 Element 0 is always in the lsb of the containing byte. */
7901 /* Zero the buffer and then set bits later where necessary. */
7910 {
7916 {
7919 }
7920 }
7922 }
7927 {
7929 {
7932 }
7943 }
7945 }
7947 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7948 specified by EXPR into the buffer PTR of length LEN bytes.
7949 Return the number of bytes placed in the buffer, or zero
7950 upon failure. */
7952 static int
7954 {
7959 }
7962 /* Subroutine of native_encode_expr. Encode the STRING_CST
7963 specified by EXPR into the buffer PTR of length LEN bytes.
7964 Return the number of bytes placed in the buffer, or zero
7965 upon failure. */
7967 static int
7969 {
7972 /* Wide-char strings are encoded in target byte-order so native
7973 encoding them is trivial. */
7988 else
7989 {
7992 {
7995 }
7997 }
7999 }
8002 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST, REAL_CST,
8003 FIXED_CST, COMPLEX_CST, STRING_CST, or VECTOR_CST specified by EXPR into
8004 the buffer PTR of size LEN bytes. If PTR is NULL, don't actually store
8005 anything, just do a dry run. Fail either if OFF is -1 and LEN isn't
8006 sufficient to encode the entire EXPR, or if OFF is out of bounds.
8007 Otherwise, start at byte offset OFF and encode at most LEN bytes.
8008 Return the number of bytes placed in the buffer, or zero upon failure. */
8010 int
8012 {
8013 /* We don't support starting at negative offset and -1 is special. */
8018 {
8039 }
8040 }
8042 /* Try to find a type whose byte size is smaller or equal to LEN bytes larger
8043 or equal to FIELDSIZE bytes, with underlying mode precision/size multiple
8044 of BITS_PER_UNIT. As native_{interpret,encode}_int works in term of
8045 machine modes, we can't just use build_nonstandard_integer_type. */
8047 tree
8049 {
8050 machine_mode mode;
8052 {
8059 {
8063 }
8064 }
8070 {
8078 }
8081 }
8083 /* Similar to native_encode_expr, but also handle CONSTRUCTORs, VCEs,
8084 NON_LVALUE_EXPRs and nops. If MASK is non-NULL (then PTR has
8085 to be non-NULL and OFF zero), then in addition to filling the
8086 bytes pointed by PTR with the value also clear any bits pointed
8087 by MASK that are known to be initialized, keep them as is for
8088 e.g. uninitialized padding bits or uninitialized fields. */
8090 int
8093 {
8096 /* We don't support starting at negative offset and -1 is special. */
8104 {
8108 mask);
8123 {
8124 tree min_index;
8142 {
8147 {
8150 }
8155 else
8159 {
8163 offset_int wpos
8171 offset_int wcount
8178 }
8180 {
8183 offset_int wpos
8191 }
8194 {
8196 {
8207 }
8209 {
8213 }
8214 }
8218 do
8219 {
8224 {
8226 {
8229 fieldsize);
8232 }
8234 ptr
8237 fieldsize,
8240 mask
8244 else
8245 {
8248 }
8249 }
8252 {
8253 /* Partial overlap. */
8259 {
8263 fieldsize);
8264 }
8265 else
8266 {
8270 }
8273 }
8275 }
8277 }
8279 }
8282 {
8292 {
8298 {
8301 }
8304 {
8313 }
8317 else
8321 {
8322 tree fld;
8324 {
8337 }
8339 {
8343 }
8346 {
8347 cnt--;
8353 }
8354 }
8359 {
8372 {
8377 }
8378 }
8379 else
8380 {
8385 }
8389 /* Prepare to deal with integral bit-fields and filter out other
8390 bit-fields that do not start and end on a byte boundary. */
8392 {
8397 {
8403 }
8409 }
8419 {
8420 /* FIXME: Handle PDP endian. */
8431 {
8434 }
8435 else
8436 {
8444 else
8445 {
8448 }
8449 }
8459 else
8472 /* If the bitfield does not start at byte boundary, handle
8473 the partial byte at the start. */
8476 {
8478 {
8483 {
8486 else
8488 }
8489 }
8490 else
8491 {
8496 {
8499 else
8503 }
8504 }
8505 }
8506 /* If the bitfield does not end at byte boundary, handle
8507 the partial byte at the end. */
8511 {
8513 {
8520 }
8521 else
8522 {
8529 }
8530 }
8534 {
8539 }
8540 else
8541 {
8542 /* Partial overlap. */
8546 {
8549 }
8553 }
8555 }
8560 {
8563 {
8566 {
8570 }
8573 }
8576 fldsize,
8586 }
8587 else
8588 {
8589 /* Partial overlap. */
8595 {
8599 fieldsize);
8600 }
8601 else
8602 {
8606 }
8609 }
8610 }
8612 }
8614 }
8615 }
8618 /* Subroutine of native_interpret_expr. Interpret the contents of
8619 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
8620 If the buffer cannot be interpreted, return NULL_TREE. */
8622 static tree
8624 {
8634 }
8637 /* Subroutine of native_interpret_expr. Interpret the contents of
8638 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
8639 If the buffer cannot be interpreted, return NULL_TREE. */
8641 static tree
8643 {
8646 double_int result;
8647 FIXED_VALUE_TYPE fixed_value;
8657 }
8660 /* Subroutine of native_interpret_expr. Interpret the contents of
8661 the buffer PTR of length LEN as a REAL_CST of type TYPE.
8662 If the buffer cannot be interpreted, return NULL_TREE. */
8664 tree
8666 {
8670 /* There are always 32 bits in each long, no matter the size of
8671 the hosts long. We handle floating point representations with
8672 up to 192 bits. */
8673 REAL_VALUE_TYPE r;
8683 {
8684 /* Both OFFSET and BYTE index within a long;
8685 bitpos indexes the whole float. */
8688 {
8695 else
8697 }
8698 else
8699 {
8702 {
8703 /* Reverse bytes within each long, or within the entire float
8704 if it's smaller than a long (for HFmode). */
8707 }
8708 }
8712 }
8716 }
8719 /* Subroutine of native_interpret_expr. Interpret the contents of
8720 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
8721 If the buffer cannot be interpreted, return NULL_TREE. */
8723 static tree
8725 {
8740 }
8742 /* Read a vector of type TYPE from the target memory image given by BYTES,
8743 which contains LEN bytes. The vector is known to be encodable using
8744 NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.
8746 Return the vector on success, otherwise return null. */
8748 static tree
8752 {
8756 {
8757 /* This is the only case in which elements can be smaller than a byte.
8758 Element 0 is always in the lsb of the containing byte. */
8765 {
8772 }
8774 }
8782 {
8788 }
8790 }
8792 /* Subroutine of native_interpret_expr. Interpret the contents of
8793 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
8794 If the buffer cannot be interpreted, return NULL_TREE. */
8796 static tree
8798 {
8807 }
8810 /* Subroutine of fold_view_convert_expr. Interpret the contents of
8811 the buffer PTR of length LEN as a constant of type TYPE. For
8812 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
8813 we return a REAL_CST, etc... If the buffer cannot be interpreted,
8814 return NULL_TREE. */
8816 tree
8818 {
8820 {
8831 {
8832 /* For floating point values in composite modes, punt if this
8833 folding doesn't preserve bit representation. As the mode doesn't
8834 have fixed precision while GCC pretends it does, there could be
8835 valid values that GCC can't really represent accurately.
8836 See PR95450. Even for other modes, e.g. x86 XFmode can have some
8837 bit combinationations which GCC doesn't preserve. */
8847 }
8861 }
8862 }
8864 /* Returns true if we can interpret the contents of a native encoding
8865 as TYPE. */
8867 bool
8869 {
8871 {
8885 }
8886 }
8888 /* Attempt to interpret aggregate of TYPE from bytes encoded in target
8889 byte order at PTR + OFF with LEN bytes. Does not handle unions. */
8891 tree
8894 {
8897 {
8904 {
8908 }
8913 {
8918 {
8923 }
8927 eltsz);
8931 }
8933 }
8937 {
8946 {
8949 {
8950 poly_int64 bitoffset;
8955 else
8965 }
8966 else
8967 {
8985 HOST_WIDE_INT rpos;
8988 else
8989 {
8992 }
9001 }
9002 }
9005 {
9015 }
9019 {
9024 }
9031 {
9035 /* FIXME: Figure out how to handle PDP endian bitfields. */
9041 else
9045 }
9047 }
9049 }
9051 /* Routines for manipulation of native_encode_expr encoded data if the encoded
9052 or extracted constant positions and/or sizes aren't byte aligned. */
9054 /* Shift left the bytes in PTR of SZ elements by AMNT bits, carrying over the
9055 bits between adjacent elements. AMNT should be within
9056 [0, BITS_PER_UNIT).
9057 Example, AMNT = 2:
9058 00011111|11100000 << 2 = 01111111|10000000
9059 PTR[1] | PTR[0] PTR[1] | PTR[0]. */
9061 void
9064 {
9073 {
9079 {
9082 }
9083 }
9084 }
9086 /* Like shift_bytes_in_array_left but for big-endian.
9087 Shift right the bytes in PTR of SZ elements by AMNT bits, carrying over the
9088 bits between adjacent elements. AMNT should be within
9089 [0, BITS_PER_UNIT).
9090 Example, AMNT = 2:
9091 00011111|11100000 >> 2 = 00000111|11111000
9092 PTR[0] | PTR[1] PTR[0] | PTR[1]. */
9094 void
9097 {
9105 {
9112 }
9113 }
9115 /* Try to view-convert VECTOR_CST EXPR to VECTOR_TYPE TYPE by operating
9116 directly on the VECTOR_CST encoding, in a way that works for variable-
9117 length vectors. Return the resulting VECTOR_CST on success or null
9118 on failure. */
9120 static tree
9122 {
9134 /* We can only preserve the semantics of a stepped pattern if the new
9135 vector element is an integer of the same size. */
9140 /* The number of bits needed to encode one element from every pattern
9141 of the original vector. */
9142 unsigned int expr_sequence_bits
9145 /* The number of bits needed to encode one element from every pattern
9146 of the result. */
9147 unsigned int type_sequence_bits
9150 /* Don't try to read more bytes than are available, which can happen
9151 for constant-sized vectors if TYPE has larger elements than EXPR_TYPE.
9152 The general VIEW_CONVERT handling can cope with that case, so there's
9153 no point complicating things here. */
9156 BITS_PER_UNIT);
9161 /* Get enough bytes of EXPR to form the new encoding. */
9169 /* Reencode the bytes as TYPE. */
9173 }
9175 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
9176 TYPE at compile-time. If we're unable to perform the conversion
9177 return NULL_TREE. */
9179 static tree
9181 {
9182 /* We support up to 512-bit values (for V8DFmode). */
9186 /* Check that the host and target are sane. */
9199 }
9201 /* Build an expression for the address of T. Folds away INDIRECT_REF
9202 to avoid confusing the gimplify process. */
9204 tree
9206 {
9207 /* The size of the object is not relevant when talking about its address. */
9212 {
9217 }
9220 {
9225 }
9232 {
9237 }
9238 else
9242 }
9244 /* Build an expression for the address of T. */
9246 tree
9248 {
9252 }
9254 /* Fold a unary expression of code CODE and type TYPE with operand
9255 OP0. Return the folded expression if folding is successful.
9256 Otherwise, return NULL_TREE. */
9258 tree
9260 {
9261 tree tem;
9262 tree arg0;
9270 {
9273 {
9274 /* Don't use STRIP_NOPS, because signedness of argument type
9275 matters. */
9277 }
9278 else
9279 {
9280 /* Strip any conversions that don't change the mode. This
9281 is safe for every expression, except for a comparison
9282 expression because its signedness is derived from its
9283 operands.
9285 Note that this is done as an internal manipulation within
9286 the constant folder, in order to find the simplest
9287 representation of the arguments so that their form can be
9288 studied. In any cases, the appropriate type conversions
9289 should be put back in the tree that will get out of the
9290 constant folder. */
9292 }
9295 {
9298 {
9302 }
9303 }
9304 }
9311 {
9318 {
9332 /* If this was a conversion, and all we did was to move into
9333 inside the COND_EXPR, bring it back out. But leave it if
9334 it is a conversion from integer to integer and the
9335 result precision is no wider than a word since such a
9336 conversion is cheap and may be optimized away by combine,
9337 while it couldn't if it were outside the COND_EXPR. Then return
9338 so we don't get into an infinite recursion loop taking the
9339 conversion out and then back in. */
9351 && (INTEGRAL_TYPE_P
9364 }
9365 }
9368 {
9374 CASE_CONVERT:
9378 {
9379 /* If we have (type) (a CMP b) and type is an integral type, return
9380 new expression involving the new type. Canonicalize
9381 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
9382 non-integral type.
9383 Do not fold the result as that would not simplify further, also
9384 folding again results in recursions. */
9394 }
9396 /* Handle (T *)&A.B.C for A being of type T and B and C
9397 living at offset zero. This occurs frequently in
9398 C++ upcasting and then accessing the base. */
9402 {
9404 tree offset;
9405 machine_mode mode;
9407 tree base
9411 /* If the reference was to a (constant) zero offset, we can use
9412 the address of the base if it has the same base type
9413 as the result type and the pointer type is unqualified. */
9421 }
9425 /* Detect assigning a bitfield. */
9427 && DECL_BIT_FIELD
9429 {
9430 /* Don't leave an assignment inside a conversion
9431 unless assigning a bitfield. */
9433 /* First do the assignment, then return converted constant. */
9438 }
9440 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
9441 constants (if x has signed type, the sign bit cannot be set
9442 in c). This folds extension into the BIT_AND_EXPR.
9443 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
9444 very likely don't have maximal range for their precision and this
9445 transformation effectively doesn't preserve non-maximal ranges. */
9449 {
9460 <= HOST_BITS_PER_WIDE_INT
9462 {
9466 cst &= HOST_WIDE_INT_M1U
9470 && !flag_syntax_only
9473 {
9477 }
9478 }
9480 {
9485 }
9486 }
9488 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
9489 cast (T1)X will fold away. We assume that this happens when X itself
9490 is a cast. */
9494 {
9498 /* If -fsanitize=alignment, avoid this optimization in GENERIC
9499 when the pointed type needs higher alignment than
9500 the p+ first operand's pointed type. */
9507 /* Similarly, avoid this optimization in GENERIC for -fsanitize=null
9508 when type is a reference type and arg00's type is not,
9509 because arg00 could be validly nullptr and if arg01 doesn't return,
9510 we don't want false positive binding of reference to nullptr. */
9512 && !in_gimple_form
9519 }
9521 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
9522 of the same precision, and X is an integer type not narrower than
9523 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
9529 {
9535 }
9537 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
9538 type of X and Y (integer types only). */
9545 {
9546 /* Be careful not to introduce new overflows. */
9547 tree mult_type;
9550 else
9554 {
9561 }
9562 }
9568 {
9575 }
9586 /* Convert fabs((double)float) into (double)fabsf(float). */
9589 {
9595 targ0));
9596 }
9600 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
9619 /* Note that the operand of this must be an int
9620 and its values must be 0 or 1.
9621 ("true" is a fixed value perhaps depending on the language,
9622 but we don't handle values other than 1 correctly yet.) */
9629 /* Fold *&X to X if X is an lvalue. */
9631 {
9638 }
9644 }
9647 /* If the operation was a conversion do _not_ mark a resulting constant
9648 with TREE_OVERFLOW if the original constant was not. These conversions
9649 have implementation defined behavior and retaining the TREE_OVERFLOW
9650 flag here would confuse later passes such as VRP. */
9651 tree
9654 {
9663 }
9665 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
9666 operands OP0 and OP1. LOC is the location of the resulting expression.
9667 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
9668 Return the folded expression if folding is successful. Otherwise,
9669 return NULL_TREE. */
9670 static tree
9673 {
9674 tree tem;
9676 /* We only do these simplifications if we are optimizing. */
9680 /* Check for things like (A || B) && (A || C). We can convert this
9681 to A || (B && C). Note that either operator can be any of the four
9682 truth and/or operations and the transformation will still be
9683 valid. Also note that we only care about order for the
9684 ANDIF and ORIF operators. If B contains side effects, this
9685 might change the truth-value of A. */
9692 {
9712 /* This case if tricky because we must either have commutative
9713 operators or else A10 must not have side-effects. */
9719 a01);
9720 }
9722 /* See if we can build a range comparison. */
9728 {
9732 }
9736 {
9740 }
9742 /* Check for the possibility of merging component references. If our
9743 lhs is another similar operation, try to merge its rhs with our
9744 rhs. Then try to merge our lhs and rhs. */
9755 logical_op_non_short_circuit
9763 {
9770 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
9771 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
9772 We don't want to pack more than two leafs to a non-IF AND/OR
9773 expression.
9774 If tree-code of left-hand operand isn't an AND/OR-IF code and not
9775 equal to IF-CODE, then we don't want to add right-hand operand.
9776 If the inner right-hand side of left-hand operand has
9777 side-effects, or isn't simple, then we can't add to it,
9778 as otherwise we might destroy if-sequence. */
9781 /* Needed for sequence points to handle trappings, and
9782 side-effects. */
9784 {
9786 arg1);
9788 tem);
9789 }
9790 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
9791 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
9794 /* Needed for sequence points to handle trappings, and
9795 side-effects. */
9797 {
9802 }
9803 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
9804 into (A OR B).
9805 For sequence point consistancy, we need to check for trapping,
9806 and side-effects. */
9810 }
9813 }
9815 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
9816 by changing CODE to reduce the magnitude of constants involved in
9817 ARG0 of the comparison.
9818 Returns a canonicalized comparison tree if a simplification was
9819 possible, otherwise returns NULL_TREE.
9820 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
9821 valid if signed overflow is undefined. */
9823 static tree
9827 {
9832 /* Match A +- CST code arg1. We can change this only if overflow
9833 is undefined. */
9836 /* In principle pointers also have undefined overflow behavior,
9837 but that causes problems elsewhere. */
9844 /* Identify the constant in arg0 and its sign. */
9848 /* Overflowed constants and zero will cause problems. */
9853 /* See if we can reduce the magnitude of the constant in
9854 arg0 by changing the comparison code. */
9855 /* A - CST < arg1 -> A - CST-1 <= arg1. */
9859 /* A + CST > arg1 -> A + CST-1 >= arg1. */
9863 /* A + CST <= arg1 -> A + CST-1 < arg1. */
9867 /* A - CST >= arg1 -> A - CST-1 > arg1. */
9871 else
9875 /* Now build the constant reduced in magnitude. But not if that
9876 would produce one outside of its types range. */
9892 }
9894 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
9895 overflow further. Try to decrease the magnitude of constants involved
9896 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
9897 and put sole constants at the second argument position.
9898 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
9900 static tree
9903 {
9904 tree t;
9909 /* Try canonicalization by simplifying arg0. */
9914 {
9918 }
9920 /* Try canonicalization by simplifying arg1 using the swapped
9921 comparison. */
9929 }
9931 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
9932 space. This is used to avoid issuing overflow warnings for
9933 expressions like &p->x which cannot wrap. */
9935 static bool
9937 {
9944 poly_wide_int wi_offset;
9950 else
9955 precision);
9970 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
9971 array. */
9980 }
9982 /* Return a positive integer when the symbol DECL is known to have
9983 a nonzero address, zero when it's known not to (e.g., it's a weak
9984 symbol), and a negative integer when the symbol is not yet in the
9985 symbol table and so whether or not its address is zero is unknown.
9986 For function local objects always return positive integer. */
9987 static int
9989 {
9990 /* Normally, don't do anything for variables and functions before symtab is
9991 built; it is quite possible that DECL will be declared weak later.
9992 But if folding_initializer, we need a constant answer now, so create
9993 the symtab entry and prevent later weak declaration. */
9996 = (folding_initializer
10001 /* Function local objects are never NULL. */
10009 }
10011 /* Subroutine of fold_binary. This routine performs all of the
10012 transformations that are common to the equality/inequality
10013 operators (EQ_EXPR and NE_EXPR) and the ordering operators
10014 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
10015 fold_binary should call fold_binary. Fold a comparison with
10016 tree code CODE and type TYPE with operands OP0 and OP1. Return
10017 the folded comparison or NULL_TREE. */
10019 static tree
10022 {
10032 /* For comparisons of pointers we can decompose it to a compile time
10033 comparison of the base objects and the offsets into the object.
10034 This requires at least one operand being an ADDR_EXPR or a
10035 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
10041 {
10044 machine_mode mode;
10048 /* Get base and offset for the access. Strip ADDR_EXPR for
10049 get_inner_reference, but put it back by stripping INDIRECT_REF
10050 off the base object if possible. indirect_baseN will be true
10051 if baseN is not an address but refers to the object itself. */
10054 {
10055 base0
10061 else
10063 }
10065 {
10069 {
10070 base0
10076 else
10078 }
10081 else
10085 {
10092 }
10093 }
10097 {
10098 base1
10104 else
10106 }
10108 {
10112 {
10113 base1
10119 else
10121 }
10124 else
10128 {
10135 }
10136 }
10138 /* If we have equivalent bases we might be able to simplify. */
10142 {
10143 /* We can fold this expression to a constant if the non-constant
10144 offset parts are equal. */
10148 && (equality_code
10149 || (indirect_base0
10152 {
10158 "occur when comparing P +- C1 with "
10160 WARN_STRICT_OVERFLOW_CONDITIONAL);
10163 {
10201 }
10202 }
10203 /* We can simplify the comparison to a comparison of the variable
10204 offset parts if the constant offset parts are equal.
10205 Be careful to use signed sizetype here because otherwise we
10206 mess with array offsets in the wrong way. This is possible
10207 because pointer arithmetic is restricted to retain within an
10208 object and overflow on pointer differences is undefined as of
10209 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
10211 && (equality_code
10212 || (indirect_base0
10215 {
10216 /* By converting to signed sizetype we cover middle-end pointer
10217 arithmetic which operates on unsigned pointer types of size
10218 type size and ARRAY_REF offsets which are properly sign or
10219 zero extended from their type in case it is narrower than
10220 sizetype. */
10223 else
10227 else
10234 "occur when comparing P +- C1 with "
10236 WARN_STRICT_OVERFLOW_COMPARISON);
10239 }
10240 }
10241 /* For equal offsets we can simplify to a comparison of the
10242 base addresses. */
10244 && (indirect_base0
10246 && (indirect_base1
10251 {
10257 }
10258 /* Comparison between an ordinary (non-weak) symbol and a null
10259 pointer can be eliminated since such symbols must have a non
10260 null address. In C, relational expressions between pointers
10261 to objects and null pointers are undefined. The results
10262 below follow the C++ rules with the additional property that
10263 every object pointer compares greater than a null pointer.
10264 */
10267 /* Avoid folding references to struct members at offset 0 to
10268 prevent tests like '&ptr->firstmember == 0' from getting
10269 eliminated. When ptr is null, although the -> expression
10270 is strictly speaking invalid, GCC retains it as a matter
10271 of QoI. See PR c/44555. */
10274 && indirect_base0
10275 /* The caller guarantees that when one of the arguments is
10276 constant (i.e., null in this case) it is second. */
10278 {
10280 {
10291 }
10292 }
10293 }
10295 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
10296 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
10297 the resulting offset is smaller in absolute value than the
10298 original one and has the same sign. */
10307 {
10312 tree cst;
10314 "occur when combining constants around "
10317 /* Put the constant on the side where it doesn't overflow and is
10318 of lower absolute value and of same sign than before. */
10325 {
10328 variable1,
10332 }
10340 {
10346 variable2);
10347 }
10348 }
10354 /* If we are comparing an expression that just has comparisons
10355 of two integer values, arithmetic expressions of those comparisons,
10356 and constants, we can simplify it. There are only three cases
10357 to check: the two values can either be equal, the first can be
10358 greater, or the second can be greater. Fold the expression for
10359 those three values. Since each value must be 0 or 1, we have
10360 eight possibilities, each of which corresponds to the constant 0
10361 or 1 or one of the six possible comparisons.
10363 This handles common cases like (a > b) == 0 but also handles
10364 expressions like ((x > y) - (y > x)) > 0, which supposedly
10365 occur in macroized code. */
10368 {
10372 /* Don't handle degenerate cases here; they should already
10373 have been handled anyway. */
10382 {
10386 /* We can't just pass T to eval_subst in case cval1 or cval2
10387 was the same as ARG1. */
10389 tree high_result
10393 arg1);
10394 tree equal_result
10398 arg1);
10399 tree low_result
10403 arg1);
10405 /* All three of these results should be 0 or 1. Confirm they are.
10406 Then use those values to select the proper code to use. */
10411 {
10412 /* Make a 3-bit mask with the high-order bit being the
10413 value for `>', the next for '=', and the low for '<'. */
10417 {
10419 /* Always false. */
10440 /* Always true. */
10442 }
10445 }
10446 }
10447 }
10450 }
10453 /* Subroutine of fold_binary. Optimize complex multiplications of the
10454 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
10455 argument EXPR represents the expression "z" of type TYPE. */
10457 static tree
10459 {
10464 {
10467 }
10469 {
10472 }
10473 else
10474 {
10478 }
10487 }
10490 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
10491 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
10492 true if successful. */
10494 static bool
10496 {
10501 {
10504 }
10506 {
10512 else
10514 }
10515 else
10521 }
10523 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
10524 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
10525 NULL_TREE otherwise. */
10527 tree
10529 {
10550 {
10551 HOST_WIDE_INT index;
10557 }
10560 {
10566 }
10567 else
10569 }
10571 /* Try to fold a pointer difference of type TYPE two address expressions of
10572 array references AREF0 and AREF1 using location LOC. Return a
10573 simplified expression for the difference or NULL_TREE. */
10575 static tree
10579 {
10584 /* If the bases are array references as well, recurse. If the bases
10585 are pointer indirections compute the difference of the pointers.
10586 If the bases are equal, we are set. */
10589 && (base_offset
10591 use_pointer_diff)))
10594 && (base_offset
10595 = use_pointer_diff
10605 {
10611 base_offset,
10614 }
10616 }
10618 /* If the real or vector real constant CST of type TYPE has an exact
10619 inverse, return it, else return NULL. */
10621 tree
10623 {
10624 REAL_VALUE_TYPE r;
10625 tree unit_type;
10626 machine_mode mode;
10629 {
10639 {
10643 tree_vector_builder elts;
10648 {
10653 }
10656 }
10660 }
10661 }
10663 /* Mask out the tz least significant bits of X of type TYPE where
10664 tz is the number of trailing zeroes in Y. */
10665 static wide_int
10667 {
10672 }
10674 /* Return true when T is an address and is known to be nonzero.
10675 For floating point we further ensure that T is not denormal.
10676 Similar logic is present in nonzero_address in rtlanal.h.
10678 If the return value is based on the assumption that signed overflow
10679 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
10680 change *STRICT_OVERFLOW_P. */
10682 static bool
10684 {
10688 /* Doing something useful for floating point would need more work. */
10694 {
10697 strict_overflow_p);
10703 strict_overflow_p);
10711 }
10714 {
10717 strict_overflow_p);
10725 strict_overflow_p);
10739 strict_overflow_p);
10743 strict_overflow_p);
10746 {
10758 }
10762 }
10764 }
10766 /* Return true when T is an address and is known to be nonzero.
10767 Handle warnings about undefined signed overflow. */
10769 bool
10771 {
10778 "determining that expression is always "
10780 WARN_STRICT_OVERFLOW_MISC);
10782 }
10784 /* Return true if T is known not to be equal to an integer W. */
10786 bool
10788 {
10789 int_range_max vr;
10791 {
10801 else
10806 /* If T has some known zero bits and W has any of those bits set,
10807 then T is known not to be equal to W. */
10815 }
10816 }
10818 /* Fold a binary expression of code CODE and type TYPE with operands
10819 OP0 and OP1. LOC is the location of the resulting expression.
10820 Return the folded expression if folding is successful. Otherwise,
10821 return NULL_TREE. */
10823 tree
10826 {
10841 /* Strip any conversions that don't change the mode. This is
10842 safe for every expression, except for a comparison expression
10843 because its signedness is derived from its operands. So, in
10844 the latter case, only strip conversions that don't change the
10845 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
10846 preserved.
10848 Note that this is done as an internal manipulation within the
10849 constant folder, in order to find the simplest representation
10850 of the arguments so that their form can be studied. In any
10851 cases, the appropriate type conversions should be put back in
10852 the tree that will get out of the constant folder. */
10855 {
10858 }
10859 else
10860 {
10863 }
10865 /* Note that TREE_CONSTANT isn't enough: static var addresses are
10866 constant but we can't do arithmetic on them. */
10868 {
10871 {
10875 }
10876 }
10878 /* If this is a commutative operation, and ARG0 is a constant, move it
10879 to ARG1 to reduce the number of tests below. */
10884 /* Likewise if this is a comparison, and ARG0 is a constant, move it
10885 to ARG1 to reduce the number of tests below. */
10894 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
10896 First check for cases where an arithmetic operation is applied to a
10897 compound, conditional, or comparison operation. Push the arithmetic
10898 operation inside the compound or conditional to see if any folding
10899 can then be done. Convert comparison to conditional for this purpose.
10900 The also optimizes non-constant cases that used to be done in
10901 expand_expr.
10903 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
10904 one of the operands is a comparison and the other is a comparison, a
10905 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
10906 code below would make the expression more complex. Change it to a
10907 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
10908 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
10921 {
10925 boolean_type_node,
10933 }
10937 {
10939 {
10944 tem);
10945 }
10947 {
10952 tem);
10953 }
10958 {
10964 }
10969 {
10975 }
10976 }
10979 {
10981 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
10984 {
10990 }
10992 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
10995 {
10996 tree base;
10997 poly_int64 coffset;
11006 }
11011 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
11017 arg1),
11019 arg0)));
11025 {
11026 /* X + (X / CST) * -CST is X % CST. */
11031 {
11040 cst0));
11041 }
11042 }
11044 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
11045 one. Make sure the type is not saturating and has the signedness of
11046 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11047 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11054 {
11058 }
11061 {
11062 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
11063 (plus (plus (mult) (mult)) (foo)) so that we can
11064 take advantage of the factoring cases below. */
11073 {
11079 else
11092 parg0),
11094 marg)),
11098 return
11104 parg1)));
11105 }
11106 }
11107 else
11108 {
11109 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
11110 to __complex__ ( x, y ). This is not the same for SNaNs or
11111 if signed zeros are involved. */
11115 {
11122 {
11126 {
11132 }
11134 {
11140 }
11141 }
11142 }
11144 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
11145 We associate floats only if the user has specified
11146 -fassociative-math. */
11150 {
11155 {
11156 tree tree0;
11159 }
11160 }
11161 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
11162 We associate floats only if the user has specified
11163 -fassociative-math. */
11167 {
11172 {
11173 tree tree0;
11176 }
11177 }
11178 }
11180 bit_rotate:
11181 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
11182 is a rotate of A by C1 bits. */
11183 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
11184 is a rotate of A by B bits.
11185 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
11186 though in this case CODE must be | and not + or ^, otherwise
11187 it doesn't return A when B is 0. */
11188 {
11190 tree rtype;
11199 /* Only create rotates in complete modes. Other cases are not
11200 expanded properly. */
11203 {
11216 {
11221 }
11226 {
11229 code0 == LSHIFT_EXPR
11232 }
11234 {
11244 {
11248 orig_tree01);
11250 }
11251 }
11255 {
11266 {
11270 orig_tree01);
11272 }
11273 }
11274 }
11275 }
11277 associate:
11278 /* In most languages, can't associate operations on floats through
11279 parentheses. Rather than remember where the parentheses were, we
11280 don't associate floats at all, unless the user has specified
11281 -fassociative-math.
11282 And, we need to make sure type is not saturating. */
11287 {
11293 /* Split both trees into variables, constants, and literals. Then
11294 associate each group together, the constants with literals,
11295 then the result with variables. This increases the chances of
11296 literals being recombined later and of generating relocatable
11297 expressions for the sum of a constant and literal. */
11305 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
11309 /* With undefined overflow prefer doing association in a type
11310 which wraps on overflow, if that is one of the operand types. */
11313 {
11321 }
11323 /* With undefined overflow we can only associate constants with one
11324 variable, and constants whose association doesn't overflow. */
11327 {
11329 {
11330 /* ??? If split_tree would handle NEGATE_EXPR we could
11331 simply reject these cases and the allowed cases would
11332 be the var0/minus_var1 ones. */
11338 {
11341 }
11348 {
11351 }
11357 /* The only case we can still associate with two variables
11358 is if they cancel out. */
11362 }
11368 }
11370 /* Only do something if we found more than two objects. Otherwise,
11371 nothing has changed and we risk infinite recursion. */
11379 {
11391 {
11395 }
11397 {
11401 }
11403 /* Preserve the MINUS_EXPR if the negative part of the literal is
11404 greater than the positive part. Otherwise, the multiplicative
11405 folding code (i.e extract_muldiv) may be fooled in case
11406 unsigned constants are subtracted, like in the following
11407 example: ((X*2 + 4) - 8U)/2. */
11409 {
11413 /* But avoid ending up with only negated parts. */
11415 {
11419 }
11420 else
11421 {
11425 }
11426 }
11428 /* Don't introduce overflows through reassociation. */
11433 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
11440 /* Eliminate minus_con0. */
11442 {
11449 else
11452 }
11454 /* Eliminate minus_var0. */
11456 {
11460 else
11463 }
11465 return
11468 }
11469 }
11475 /* Fold &a[i] - &a[j] to i-j. */
11480 {
11484 code
11488 }
11490 /* Further transformations are not for pointers. */
11494 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
11497 /* If arg0 is e.g. unsigned int and type is int, then this could
11498 introduce UB, because if A is INT_MIN at runtime, the original
11499 expression can be well defined while the latter is not.
11500 See PR83269. */
11509 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
11510 __complex__ ( x, -y ). This is not the same for SNaNs or if
11511 signed zeros are involved. */
11515 {
11522 {
11526 {
11528 arg1r ? arg1r
11533 }
11535 {
11539 arg1i ? arg1i
11542 }
11543 }
11544 }
11546 /* A - B -> A + (-B) if B is easily negatable. */
11550 /* Avoid this transformation if B is a positive REAL_CST. */
11558 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
11559 one. Make sure the type is not saturating and has the signedness of
11560 the stripped operands, as fold_plusminus_mult_expr will re-associate.
11561 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
11568 {
11572 }
11578 {
11579 /* Transform x * -C into -x * C if x is easily negatable. */
11594 {
11597 "occur when simplifying "
11599 WARN_STRICT_OVERFLOW_MISC);
11601 }
11603 /* Optimize z * conj(z) for integer complex numbers. */
11610 }
11611 else
11612 {
11613 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
11614 This is not the same for NaNs or if signed zeros are
11615 involved. */
11621 {
11624 return
11630 return
11635 }
11637 /* Optimize z * conj(z) for floating point complex numbers.
11638 Guarded by flag_unsafe_math_optimizations as non-finite
11639 imaginary components don't produce scalar results. */
11648 }
11652 /* Canonicalize (X & C1) | C2. */
11656 {
11661 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
11669 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
11671 {
11674 }
11676 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
11677 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
11678 mode which allows further optimizations. */
11683 {
11688 {
11691 }
11692 }
11695 {
11700 }
11701 }
11703 /* See if this can be simplified into a rotate first. If that
11704 is unsuccessful continue in the association code. */
11708 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
11716 /* See if this can be simplified into a rotate first. If that
11717 is unsuccessful continue in the association code. */
11721 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
11726 {
11727 tree tem2;
11734 }
11735 /* Fold ~X & 1 as (X & 1) == 0. */
11739 {
11740 tree tem2;
11747 }
11748 /* Fold !X & 1 as X == 0. */
11751 {
11755 }
11757 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
11758 multiple of 1 << CST. */
11760 {
11767 }
11769 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
11770 bits from CST2. */
11774 {
11776 wide_int masked
11783 {
11784 /* Avoid the transform if arg1 is a mask of some
11785 mode which allows further optimizations. */
11792 }
11793 }
11795 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
11798 {
11803 return
11805 }
11810 /* Don't touch a floating-point divide by zero unless the mode
11811 of the constant can represent infinity. */
11817 /* (-A) / (-B) -> A / B */
11829 /* Fall through */
11832 /* Simplify A / (B << N) where A and B are positive and B is
11833 a power of 2, to A >> (N + log2(B)). */
11838 {
11841 {
11849 WARN_STRICT_OVERFLOW_MISC);
11855 }
11856 }
11858 /* Fall through */
11866 /* Convert -A / -B to A / B when the type is signed and overflow is
11867 undefined. */
11871 {
11874 "when distributing negation across "
11876 WARN_STRICT_OVERFLOW_MISC);
11881 }
11885 {
11888 "when distributing negation across "
11890 WARN_STRICT_OVERFLOW_MISC);
11895 }
11897 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
11898 operation, EXACT_DIV_EXPR.
11900 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
11901 At one time others generated faster code, it's not clear if they do
11902 after the last round to changes to the DIV code in expmed.cc. */
11913 {
11917 WARN_STRICT_OVERFLOW_MISC);
11919 }
11931 {
11935 WARN_STRICT_OVERFLOW_MISC);
11937 }
11945 /* Since negative shift count is not well-defined,
11946 don't try to compute it in the compiler. */
11952 /* If we have a rotate of a bit operation with the rotate count and
11953 the second operand of the bit operation both constant,
11954 permute the two operations. */
11960 {
11968 }
11970 /* Two consecutive rotates adding up to the some integer
11971 multiple of the precision of the type can be ignored. */
11987 /* Note that the operands of this must be ints
11988 and their values must be 0 or 1.
11989 ("true" is a fixed value perhaps depending on the language.) */
11990 /* If first arg is constant zero, return it. */
11993 /* FALLTHRU */
11995 /* If either arg is constant true, drop it. */
11999 /* Preserve sequence points. */
12002 /* If second arg is constant zero, result is zero, but first arg
12003 must be evaluated. */
12006 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
12007 case will be handled here. */
12011 /* !X && X is always false. */
12015 /* X && !X is always false. */
12020 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
12021 means A >= Y && A != MAX, but in this case we know that
12022 A < X <= MAX. */
12026 {
12038 }
12047 /* Note that the operands of this must be ints
12048 and their values must be 0 or true.
12049 ("true" is a fixed value perhaps depending on the language.) */
12050 /* If first arg is constant true, return it. */
12053 /* FALLTHRU */
12055 /* If either arg is constant zero, drop it. */
12059 /* Preserve sequence points. */
12062 /* If second arg is constant true, result is true, but we must
12063 evaluate first arg. */
12066 /* Likewise for first arg, but note this only occurs here for
12067 TRUTH_OR_EXPR. */
12071 /* !X || X is always true. */
12075 /* X || !X is always true. */
12080 /* (X && !Y) || (!X && Y) is X ^ Y */
12083 {
12100 }
12109 /* If the second arg is constant zero, drop it. */
12112 /* If the second arg is constant true, this is a logical inversion. */
12114 {
12117 }
12118 /* Identical arguments cancel to zero. */
12122 /* !X ^ X is always true. */
12127 /* X ^ !X is always true. */
12143 /* bool_var != 1 becomes !bool_var. */
12150 /* bool_var == 0 becomes !bool_var. */
12157 /* !exp != 0 becomes !exp */
12162 /* If this is an EQ or NE comparison with zero and ARG0 is
12163 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
12164 two operations, but the latter can be done in one less insn
12165 on machines that have only two-operand insns or on which a
12166 constant cannot be the first operand. */
12169 {
12174 {
12182 }
12185 {
12193 }
12194 }
12196 /* If this is a comparison of a field, we may be able to simplify it. */
12199 /* Handle the constant case even without -O
12200 to make sure the warnings are given. */
12202 {
12206 }
12208 /* Optimize comparisons of strlen vs zero to a compare of the
12209 first character of the string vs zero. To wit,
12210 strlen(ptr) == 0 => *ptr == 0
12211 strlen(ptr) != 0 => *ptr != 0
12212 Other cases should reduce to one of these two (or a constant)
12213 due to the return value of strlen being unsigned. */
12215 {
12223 {
12224 tree ptrtype
12226 TYPE_QUAL_CONST));
12232 }
12233 }
12235 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
12236 of X. Similarly fold (X >> C) == 0 into X >= 0. */
12240 {
12245 {
12247 {
12250 }
12253 }
12254 }
12256 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
12257 (X & C) == 0 when C is a single bit. */
12262 {
12269 arg1));
12270 }
12272 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
12273 constant C is a power of two, i.e. a single bit. */
12280 {
12284 }
12286 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
12287 when is C is a power of two, i.e. a single bit. */
12294 {
12300 }
12304 {
12311 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
12312 operand_equal_p guarantees no side-effects so we don't need
12313 to use omit_one_operand on Z. */
12317 arg10));
12321 arg11));
12325 arg10));
12329 arg11));
12331 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
12334 {
12340 }
12341 }
12343 /* Attempt to simplify equality/inequality comparisons of complex
12344 values. Only lower the comparison if the result is known or
12345 can be simplified to a single scalar comparison. */
12350 {
12355 {
12358 }
12359 else
12360 {
12363 }
12366 {
12369 }
12370 else
12371 {
12374 }
12378 {
12380 {
12385 }
12386 else
12387 {
12392 }
12393 }
12397 {
12399 {
12404 }
12405 else
12406 {
12411 }
12412 }
12413 }
12425 /* Transform comparisons of the form X +- C CMP X. */
12430 {
12435 /* (X - c) > X becomes false. */
12441 /* Likewise (X + c) < X becomes false. */
12447 /* Convert (X - c) <= X to true. */
12454 /* Convert (X + c) >= X to true. */
12460 }
12462 /* If we are comparing an ABS_EXPR with a constant, we can
12463 convert all the cases into explicit comparisons, but they may
12464 well not be faster than doing the ABS and one comparison.
12465 But ABS (X) <= C is a range comparison, which becomes a subtraction
12466 and a comparison, and is probably faster. */
12480 /* Convert ABS_EXPR<x> >= 0 to true. */
12487 {
12490 "when simplifying comparison of "
12492 WARN_STRICT_OVERFLOW_CONDITIONAL);
12495 arg0);
12496 }
12498 /* Convert ABS_EXPR<x> < 0 to false. */
12503 {
12506 "when simplifying comparison of "
12508 WARN_STRICT_OVERFLOW_CONDITIONAL);
12511 arg0);
12512 }
12514 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
12515 and similarly for >= into !=. */
12525 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
12526 otherwise Y might be >= # of bits in X's type and thus e.g.
12527 (unsigned char) (1 << Y) for Y 15 might be 0.
12528 If the cast is widening, then 1 << Y should have unsigned type,
12529 otherwise if Y is number of bits in the signed shift type minus 1,
12530 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
12531 31 might be 0xffffffff80000000. */
12544 {
12550 }
12562 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
12563 {
12575 }
12580 /* When pedantic, a compound expression can be neither an lvalue
12581 nor an integer constant expression. */
12584 /* Don't let (0, 0) be null pointer constant. */
12592 }
12594 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
12595 ((A & N) + B) & M -> (A + B) & M
12596 Similarly if (N & M) == 0,
12597 ((A | N) + B) & M -> (A + B) & M
12598 and for - instead of + (or unary - instead of +)
12599 and/or ^ instead of |.
12600 If B is constant and (B & M) == 0, fold into A & M.
12602 This function is a helper for match.pd patterns. Return non-NULL
12603 type in which the simplified operation should be performed only
12604 if any optimization is possible.
12606 ARG1 is M above, ARG00 is left operand of +/-, if CODE00 is BIT_*_EXPR,
12607 then ARG00{0,1} are operands of that bitop, otherwise CODE00 is ERROR_MARK.
12608 Similarly for ARG01, CODE01 and ARG01{0,1}, just for the right operand of
12609 +/-. */
12610 tree
12615 {
12630 wide_int cst0;
12632 /* Now we know that arg0 is (C + D) or (C - D) or -C and
12633 arg1 (M) is == (1LL << cst) - 1.
12634 Store C into PMOP[0] and D into PMOP[1]. */
12641 {
12648 {
12651 }
12654 /* If C or D is of the form (A & N) where
12655 (N & M) == M, or of the form (A | N) or
12656 (A ^ N) where (N & M) == 0, replace it with A. */
12662 /* If C or D is a N where (N & M) == 0, it can be
12663 omitted (replaced with 0). */
12668 /* Similarly, with C - N where (-N & M) == 0. */
12676 }
12678 /* Only build anything new if we optimized one or both arguments above. */
12684 else
12686 }
12688 /* Used by contains_label_[p1]. */
12690 struct contains_label_data
12691 {
12694 };
12696 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
12697 a LABEL_EXPR or CASE_LABEL_EXPR not inside of another SWITCH_EXPR; otherwise
12698 return NULL_TREE. Do not check the subtrees of GOTO_EXPR. */
12700 static tree
12702 {
12705 {
12716 {
12724 }
12733 }
12734 }
12736 /* Return whether the sub-tree ST contains a label which is accessible from
12737 outside the sub-tree. */
12739 static bool
12741 {
12745 }
12747 /* Fold a ternary expression of code CODE and type TYPE with operands
12748 OP0, OP1, and OP2. Return the folded expression if folding is
12749 successful. Otherwise, return NULL_TREE. */
12751 tree
12754 {
12755 tree tem;
12762 /* If this is a commutative operation, and OP0 is a constant, move it
12763 to OP1 to reduce the number of tests below. */
12772 /* Strip any conversions that don't change the mode. This is safe
12773 for every expression, except for a comparison expression because
12774 its signedness is derived from its operands. So, in the latter
12775 case, only strip conversions that don't change the signedness.
12777 Note that this is done as an internal manipulation within the
12778 constant folder, in order to find the simplest representation of
12779 the arguments so that their form can be studied. In any cases,
12780 the appropriate type conversions should be put back in the tree
12781 that will get out of the constant folder. */
12783 {
12786 }
12789 {
12792 }
12795 {
12798 }
12801 {
12805 {
12811 }
12816 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
12817 so all simple results must be passed through pedantic_non_lvalue. */
12819 {
12822 /* Only optimize constant conditions when the selected branch
12823 has the same type as the COND_EXPR. This avoids optimizing
12824 away "c ? x : throw", where the throw has a void type.
12825 Avoid throwing away that operand which contains label. */
12832 }
12834 {
12841 {
12844 {
12852 }
12857 }
12858 }
12860 /* If we have A op B ? A : C, we may be able to convert this to a
12861 simpler expression, depending on the operation and the values
12862 of B and C. Signed zeros prevent all of these transformations,
12863 for reasons given above each one.
12865 Also try swapping the arguments and inverting the conditional. */
12869 {
12876 }
12881 {
12888 arg00,
12889 arg01,
12893 }
12895 /* If the second operand is simpler than the third, swap them
12896 since that produces better jump optimization results. */
12899 {
12901 /* See if this can be inverted. If it can't, possibly because
12902 it was a floating-point inequality comparison, don't do
12903 anything. */
12907 }
12909 /* Convert A ? 1 : 0 to simply A. */
12914 /* If we try to convert OP0 to our type, the
12915 call to fold will try to move the conversion inside
12916 a COND, which will recurse. In that case, the COND_EXPR
12917 is probably the best choice, so leave it alone. */
12921 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
12922 over COND_EXPR in cases such as floating point comparisons. */
12931 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
12936 {
12937 /* sign_bit_p looks through both zero and sign extensions,
12938 but for this optimization only sign extensions are
12939 usable. */
12942 {
12945 {
12948 }
12950 }
12951 /* sign_bit_p only checks ARG1 bits within A's precision.
12952 If <sign bit of A> has wider type than A, bits outside
12953 of A's precision in <sign bit of A> need to be checked.
12954 If they are all 0, this optimization needs to be done
12955 in unsigned A's type, if they are all 1 in signed A's type,
12956 otherwise this can't be done. */
12962 {
12964 tree tem_type;
12977 {
12980 }
12982 {
12985 }
12986 else
12988 }
12991 return
12997 arg1)));
12998 }
13000 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
13001 already handled above. */
13006 {
13016 op1);
13017 }
13019 /* A & N ? N : 0 is simply A & N if N is a power of two. This
13020 is probably obsolete because the first operand should be a
13021 truth value (that's why we have the two cases above), but let's
13022 leave it in until we can confirm this for all front-ends. */
13030 /* operand_equal_p compares just value, not precision, so e.g.
13031 arg1 could be 8-bit -128 and be power of two, but BIT_AND_EXPR
13032 second operand 32-bit -128, which is not a power of two (or vice
13033 versa. */
13037 /* Disable the transformations below for vectors, since
13038 fold_binary_op_with_conditional_arg may undo them immediately,
13039 yielding an infinite loop. */
13043 /* Convert A ? B : 0 into A && B if A and B are truth values. */
13052 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
13057 {
13059 /* Only perform transformation if ARG0 is easily inverted. */
13063 ? BIT_IOR_EXPR
13066 op1);
13067 }
13069 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
13074 {
13076 /* Only perform transformation if ARG0 is easily inverted. */
13082 op2);
13083 }
13085 /* Convert A ? 1 : B into A || B if A and B are truth values. */
13097 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
13098 of fold_ternary on them. */
13108 {
13110 unsigned HOST_WIDE_INT width
13121 {
13126 {
13128 {
13133 }
13139 }
13140 }
13141 }
13143 /* On constants we can use native encode/interpret to constant
13144 fold (nearly) all BIT_FIELD_REFs. */
13150 {
13153 /* Limit us to a reasonable amount of work. To relax the
13154 other limitations we need bit-shifting of the buffer
13155 and rounding up the size. */
13159 {
13161 unsigned HOST_WIDE_INT len
13166 {
13171 }
13172 }
13173 }
13178 /* Perform constant folding of BIT_INSERT_EXPR. */
13182 {
13183 /* Build a vector of integers from the tree mask. */
13184 vec_perm_builder builder;
13188 /* Create a vec_perm_indices for the integer vector. */
13193 }
13197 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
13200 {
13206 wide_int tem2
13210 }
13215 {
13217 unsigned HOST_WIDE_INT elsize
13220 {
13226 {
13232 }
13233 }
13234 }
13240 }
13242 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
13243 of an array (or vector). *CTOR_IDX if non-NULL is updated with the
13244 constructor element index of the value returned. If the element is
13245 not found NULL_TREE is returned and *CTOR_IDX is updated to
13246 the index of the element after the ACCESS_INDEX position (which
13247 may be outside of the CTOR array). */
13249 tree
13252 {
13258 {
13261 {
13262 /* Static constructors for variably sized objects makes no sense. */
13265 /* ??? When it is obvious that the range is signed, treat it so. */
13270 {
13272 low_bound
13274 SIGNED);
13275 }
13276 else
13277 {
13280 }
13281 }
13282 }
13286 index_sgn);
13298 {
13299 /* Array constructor might explicitly set index, or specify a range,
13300 or leave index NULL meaning that it is next index after previous
13301 one. */
13303 {
13305 max_index = index
13307 else
13308 {
13311 index_sgn);
13312 max_index
13314 index_sgn);
13316 }
13317 }
13319 {
13325 }
13326 else
13329 /* Do we have match? */
13331 {
13333 {
13337 }
13338 }
13340 /* We're past the element we search for. Note during parsing
13341 the elements might not be sorted.
13342 ??? We should use a binary search and a flag on the
13343 CONSTRUCTOR as to whether elements are sorted in declaration
13344 order. */
13346 }
13350 }
13352 /* Perform constant folding and related simplification of EXPR.
13353 The related simplifications include x*1 => x, x*0 => 0, etc.,
13354 and application of the associative law.
13355 NOP_EXPR conversions may be removed freely (as long as we
13356 are careful not to change the type of the overall expression).
13357 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
13358 but we can constant-fold them if they have constant operands. */
13360 #ifdef ENABLE_FOLD_CHECKING
13361 # define fold(x) fold_1 (x)
13363 static
13364 #endif
13365 tree
13367 {
13371 tree tem;
13374 /* Return right away if a constant. */
13378 /* CALL_EXPR-like objects with variable numbers of operands are
13379 treated specially. */
13381 {
13383 {
13386 }
13388 }
13391 {
13396 {
13414 }
13415 }
13418 {
13420 {
13427 {
13432 }
13435 }
13437 /* Return a VECTOR_CST if possible. */
13439 {
13445 tree val;
13451 }
13459 }
13461 #ifdef ENABLE_FOLD_CHECKING
13462 #undef fold
13469 /* When --enable-checking=fold, compute a digest of expr before
13470 and after actual fold call to see if fold did not accidentally
13471 change original expr. */
13473 tree
13475 {
13476 tree ret;
13496 }
13498 void
13500 {
13511 }
13513 static void
13515 {
13517 }
13519 static void
13522 {
13528 recursive_label:
13538 {
13539 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
13547 }
13555 {
13556 /* Allow these fields to be modified. */
13557 tree tmp;
13568 {
13571 }
13572 }
13574 {
13575 /* Allow the no-warning bit to be set. Perhaps we shouldn't allow
13576 that and change builtins.cc etc. instead - see PR89543. */
13582 }
13593 {
13596 {
13612 }
13616 {
13629 }
13646 {
13652 }
13655 {
13657 {
13660 }
13662 }
13673 {
13676 }
13684 }
13685 }
13687 /* Helper function for outputting the checksum of a tree T. When
13688 debugging with gdb, you can "define mynext" to be "next" followed
13689 by "call debug_fold_checksum (op0)", then just trace down till the
13690 outputs differ. */
13692 DEBUG_FUNCTION void
13694 {
13709 }
13711 #endif
13713 /* Fold a unary tree expression with code CODE of type TYPE with an
13714 operand OP0. LOC is the location of the resulting expression.
13715 Return a folded expression if successful. Otherwise, return a tree
13716 expression with code CODE of type TYPE with an operand OP0. */
13718 tree
13721 {
13722 tree tem;
13723 #ifdef ENABLE_FOLD_CHECKING
13732 #endif
13738 #ifdef ENABLE_FOLD_CHECKING
13745 #endif
13747 }
13749 /* Fold a binary tree expression with code CODE of type TYPE with
13750 operands OP0 and OP1. LOC is the location of the resulting
13751 expression. Return a folded expression if successful. Otherwise,
13752 return a tree expression with code CODE of type TYPE with operands
13753 OP0 and OP1. */
13755 tree
13758 MEM_STAT_DECL)
13759 {
13760 tree tem;
13761 #ifdef ENABLE_FOLD_CHECKING
13778 #endif
13784 #ifdef ENABLE_FOLD_CHECKING
13799 #endif
13801 }
13803 /* Fold a ternary tree expression with code CODE of type TYPE with
13804 operands OP0, OP1, and OP2. Return a folded expression if
13805 successful. Otherwise, return a tree expression with code CODE of
13806 type TYPE with operands OP0, OP1, and OP2. */
13808 tree
13811 {
13812 tree tem;
13813 #ifdef ENABLE_FOLD_CHECKING
13837 #endif
13844 #ifdef ENABLE_FOLD_CHECKING
13867 #endif
13869 }
13871 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
13872 arguments in ARGARRAY, and a null static chain.
13873 Return a folded expression if successful. Otherwise, return a CALL_EXPR
13874 of type TYPE from the given operands as constructed by build_call_array. */
13876 tree
13879 {
13880 tree tem;
13881 #ifdef ENABLE_FOLD_CHECKING
13900 #endif
13906 #ifdef ENABLE_FOLD_CHECKING
13922 #endif
13924 }
13926 /* Perform constant folding and related simplification of initializer
13927 expression EXPR. These behave identically to "fold_buildN" but ignore
13928 potential run-time traps and exceptions that fold must preserve. */
13930 #define START_FOLD_INIT \
13931 int saved_signaling_nans = flag_signaling_nans;\
13932 int saved_trapping_math = flag_trapping_math;\
13933 int saved_rounding_math = flag_rounding_math;\
13934 int saved_trapv = flag_trapv;\
13935 int saved_folding_initializer = folding_initializer;\
13936 flag_signaling_nans = 0;\
13937 flag_trapping_math = 0;\
13938 flag_rounding_math = 0;\
13939 flag_trapv = 0;\
13940 folding_initializer = 1;
13942 #define END_FOLD_INIT \
13943 flag_signaling_nans = saved_signaling_nans;\
13944 flag_trapping_math = saved_trapping_math;\
13945 flag_rounding_math = saved_rounding_math;\
13946 flag_trapv = saved_trapv;\
13947 folding_initializer = saved_folding_initializer;
13949 tree
13951 {
13952 tree result;
13953 START_FOLD_INIT;
13957 END_FOLD_INIT;
13959 }
13961 tree
13964 {
13965 tree result;
13966 START_FOLD_INIT;
13970 END_FOLD_INIT;
13972 }
13974 tree
13977 {
13978 tree result;
13979 START_FOLD_INIT;
13983 END_FOLD_INIT;
13985 }
13987 tree
13990 {
13991 tree result;
13992 START_FOLD_INIT;
13996 END_FOLD_INIT;
13998 }
14000 tree
14003 {
14004 tree result;
14005 START_FOLD_INIT;
14009 END_FOLD_INIT;
14011 }
14013 #undef START_FOLD_INIT
14014 #undef END_FOLD_INIT
14016 /* Determine if first argument is a multiple of second argument. Return
14017 false if it is not, or we cannot easily determined it to be.
14019 An example of the sort of thing we care about (at this point; this routine
14020 could surely be made more general, and expanded to do what the *_DIV_EXPR's
14021 fold cases do now) is discovering that
14023 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14025 is a multiple of
14027 SAVE_EXPR (J * 8)
14029 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
14031 This code also handles discovering that
14033 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
14035 is a multiple of 8 so we don't have to worry about dealing with a
14036 possible remainder.
14038 Note that we *look* inside a SAVE_EXPR only to determine how it was
14039 calculated; it is not safe for fold to do much of anything else with the
14040 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
14041 at run time. For example, the latter example above *cannot* be implemented
14042 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
14043 evaluation time of the original SAVE_EXPR is not necessarily the same at
14044 the time the new expression is evaluated. The only optimization of this
14045 sort that would be valid is changing
14047 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
14049 divided by 8 to
14051 SAVE_EXPR (I) * SAVE_EXPR (J)
14053 (where the same SAVE_EXPR (J) is used in the original and the
14054 transformed version).
14056 NOWRAP specifies whether all outer operations in TYPE should
14057 be considered not wrapping. Any type conversion within TOP acts
14058 as a barrier and we will fall back to NOWRAP being false.
14059 NOWRAP is mostly used to treat expressions in TYPE_SIZE and friends
14060 as not wrapping even though they are generally using unsigned arithmetic. */
14062 bool
14064 {
14075 {
14077 /* Bitwise and provides a power of two multiple. If the mask is
14078 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
14085 /* If the multiplication can wrap we cannot recurse further unless
14086 the bottom is a power of two which is where wrapping does not
14087 matter. */
14093 {
14099 {
14102 /* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
14104 {
14108 {
14111 }
14112 }
14114 }
14115 }
14120 /* Handle X << CST as X * (1 << CST) and only process the constant. */
14122 {
14125 {
14126 wide_int mul_op
14130 nowrap);
14131 }
14132 }
14137 /* If the addition or subtraction can wrap we cannot recurse further
14138 unless bottom is a power of two which is where wrapping does not
14139 matter. */
14145 /* Handle cases like op0 + 0xfffffffd as op0 - 3 if the expression has
14146 unsigned type. For example, (X / 3) + 0xfffffffd is multiple of 3,
14147 but 0xfffffffd is not. */
14150 && nowrap
14155 /* It is impossible to prove if op0 +- op1 is multiple of bottom
14156 precisely, so be conservative here checking if both op0 and op1
14157 are multiple of bottom. Note we check the second operand first
14158 since it's usually simpler. */
14162 CASE_CONVERT:
14163 /* Can't handle conversions from non-integral or wider integral type. */
14168 /* NOWRAP only extends to operations in the outermost type so
14169 make sure to strip it off here. */
14184 SIGNED);
14190 {
14193 /* Check for special cases to see if top is defined as multiple
14194 of bottom:
14196 top = (X & ~(bottom - 1) ; bottom is power of 2
14198 or
14200 Y = X % bottom
14201 top = X - Y. */
14220 }
14222 /* fall through */
14230 }
14231 }
14233 /* Return true if expression X cannot be (or contain) a NaN or infinity.
14234 This function returns true for integer expressions, and returns
14235 false if uncertain. */
14237 bool
14239 {
14244 {
14267 {
14268 CASE_CFN_FABS:
14269 CASE_CFN_FABS_FN:
14271 CASE_CFN_FMAX:
14272 CASE_CFN_FMAX_FN:
14273 CASE_CFN_FMIN:
14274 CASE_CFN_FMIN_FN:
14279 }
14283 }
14284 }
14286 /* Return true if expression X evaluates to an infinity.
14287 This function returns false for integer expressions. */
14289 bool
14291 {
14295 {
14308 }
14309 }
14311 /* Return true if expression X could evaluate to an infinity.
14312 This function returns false for integer expressions, and returns
14313 true if uncertain. */
14315 bool
14317 {
14321 {
14334 }
14335 }
14337 /* Return true if expression X evaluates to a signaling NaN.
14338 This function returns false for integer expressions. */
14340 bool
14342 {
14346 {
14357 }
14358 }
14360 /* Return true if expression X could evaluate to a signaling NaN.
14361 This function returns false for integer expressions, and returns
14362 true if uncertain. */
14364 bool
14366 {
14370 {
14390 {
14391 CASE_CFN_FABS:
14392 CASE_CFN_FABS_FN:
14394 CASE_CFN_FMAX:
14395 CASE_CFN_FMAX_FN:
14396 CASE_CFN_FMIN:
14397 CASE_CFN_FMIN_FN:
14402 }
14405 }
14406 }
14408 /* Return true if expression X evaluates to a NaN.
14409 This function returns false for integer expressions. */
14411 bool
14413 {
14417 {
14428 }
14429 }
14431 /* Return true if expression X could evaluate to a NaN.
14432 This function returns false for integer expressions, and returns
14433 true if uncertain. */
14435 bool
14437 {
14441 {
14466 {
14467 CASE_CFN_FABS:
14468 CASE_CFN_FABS_FN:
14470 CASE_CFN_FMAX:
14471 CASE_CFN_FMAX_FN:
14472 CASE_CFN_FMIN:
14473 CASE_CFN_FMIN_FN:
14478 }
14481 }
14482 }
14484 /* Return true if expression X could evaluate to -0.0.
14485 This function returns true if uncertain. */
14487 bool
14489 {
14493 {
14508 {
14509 CASE_CFN_FABS:
14510 CASE_CFN_FABS_FN:
14514 }
14517 }
14518 /* Ideally !(tree_expr_nonzero_p (X) || tree_expr_nonnegative_p (X))
14519 * but currently those predicates require tree and not const_tree. */
14521 }
14523 #define tree_expr_nonnegative_warnv_p(X, Y) \
14526 #define RECURSE(X) \
14527 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
14529 /* Return true if CODE or TYPE is known to be non-negative. */
14531 static bool
14533 {
14537 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
14538 have a signed:1 type (where the value is -1 and 0). */
14541 }
14543 /* Return true if (CODE OP0) is known to be non-negative. If the return
14544 value is based on the assumption that signed overflow is undefined,
14545 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14546 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14548 bool
14551 {
14556 {
14558 /* We can't return 1 if flag_wrapv is set because
14559 ABS_EXPR<INT_MIN> = INT_MIN. */
14563 {
14566 }
14574 CASE_CONVERT:
14575 {
14580 {
14584 {
14588 }
14589 }
14591 {
14597 }
14598 }
14603 }
14605 /* We don't know sign of `t', so be conservative and return false. */
14607 }
14609 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
14610 value is based on the assumption that signed overflow is undefined,
14611 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14612 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14614 bool
14618 {
14623 {
14629 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
14630 both unsigned and at least 2 bits shorter than the result. */
14634 {
14639 {
14643 }
14644 }
14649 {
14650 /* x * x is always non-negative for floating point x
14651 or without overflow. */
14654 {
14659 }
14660 }
14662 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
14663 both unsigned and their total bits is shorter than the result. */
14667 {
14686 {
14696 }
14697 }
14704 /* Usually RECURSE (op0) || RECURSE (op1) but NaNs complicate
14705 things. */
14730 }
14732 /* We don't know sign of `t', so be conservative and return false. */
14734 }
14736 /* Return true if T is known to be non-negative. If the return
14737 value is based on the assumption that signed overflow is undefined,
14738 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14739 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14741 bool
14743 {
14748 {
14762 /* Limit the depth of recursion to avoid quadratic behavior.
14763 This is expected to catch almost all occurrences in practice.
14764 If this code misses important cases that unbounded recursion
14765 would not, passes that need this information could be revised
14766 to provide it through dataflow propagation. */
14774 }
14775 }
14777 /* Return true if T is known to be non-negative. If the return
14778 value is based on the assumption that signed overflow is undefined,
14779 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14780 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14782 bool
14785 {
14787 {
14788 CASE_CFN_ACOS:
14789 CASE_CFN_ACOS_FN:
14790 CASE_CFN_ACOSH:
14791 CASE_CFN_ACOSH_FN:
14792 CASE_CFN_CABS:
14793 CASE_CFN_CABS_FN:
14794 CASE_CFN_COSH:
14795 CASE_CFN_COSH_FN:
14796 CASE_CFN_ERFC:
14797 CASE_CFN_ERFC_FN:
14798 CASE_CFN_EXP:
14799 CASE_CFN_EXP_FN:
14800 CASE_CFN_EXP10:
14801 CASE_CFN_EXP2:
14802 CASE_CFN_EXP2_FN:
14803 CASE_CFN_FABS:
14804 CASE_CFN_FABS_FN:
14805 CASE_CFN_FDIM:
14806 CASE_CFN_FDIM_FN:
14807 CASE_CFN_HYPOT:
14808 CASE_CFN_HYPOT_FN:
14809 CASE_CFN_POW10:
14810 CASE_CFN_FFS:
14811 CASE_CFN_PARITY:
14812 CASE_CFN_POPCOUNT:
14813 CASE_CFN_CLZ:
14814 CASE_CFN_CLRSB:
14819 /* Always true. */
14822 CASE_CFN_SQRT:
14823 CASE_CFN_SQRT_FN:
14824 /* sqrt(-0.0) is -0.0. */
14829 CASE_CFN_ASINH:
14830 CASE_CFN_ASINH_FN:
14831 CASE_CFN_ATAN:
14832 CASE_CFN_ATAN_FN:
14833 CASE_CFN_ATANH:
14834 CASE_CFN_ATANH_FN:
14835 CASE_CFN_CBRT:
14836 CASE_CFN_CBRT_FN:
14837 CASE_CFN_CEIL:
14838 CASE_CFN_CEIL_FN:
14839 CASE_CFN_ERF:
14840 CASE_CFN_ERF_FN:
14841 CASE_CFN_EXPM1:
14842 CASE_CFN_EXPM1_FN:
14843 CASE_CFN_FLOOR:
14844 CASE_CFN_FLOOR_FN:
14845 CASE_CFN_FMOD:
14846 CASE_CFN_FMOD_FN:
14847 CASE_CFN_FREXP:
14848 CASE_CFN_FREXP_FN:
14849 CASE_CFN_ICEIL:
14850 CASE_CFN_IFLOOR:
14851 CASE_CFN_IRINT:
14852 CASE_CFN_IROUND:
14853 CASE_CFN_LCEIL:
14854 CASE_CFN_LDEXP:
14855 CASE_CFN_LFLOOR:
14856 CASE_CFN_LLCEIL:
14857 CASE_CFN_LLFLOOR:
14858 CASE_CFN_LLRINT:
14859 CASE_CFN_LLRINT_FN:
14860 CASE_CFN_LLROUND:
14861 CASE_CFN_LLROUND_FN:
14862 CASE_CFN_LRINT:
14863 CASE_CFN_LRINT_FN:
14864 CASE_CFN_LROUND:
14865 CASE_CFN_LROUND_FN:
14866 CASE_CFN_MODF:
14867 CASE_CFN_MODF_FN:
14868 CASE_CFN_NEARBYINT:
14869 CASE_CFN_NEARBYINT_FN:
14870 CASE_CFN_RINT:
14871 CASE_CFN_RINT_FN:
14872 CASE_CFN_ROUND:
14873 CASE_CFN_ROUND_FN:
14874 CASE_CFN_ROUNDEVEN:
14875 CASE_CFN_ROUNDEVEN_FN:
14876 CASE_CFN_SCALB:
14877 CASE_CFN_SCALBLN:
14878 CASE_CFN_SCALBLN_FN:
14879 CASE_CFN_SCALBN:
14880 CASE_CFN_SCALBN_FN:
14881 CASE_CFN_SIGNBIT:
14882 CASE_CFN_SIGNIFICAND:
14883 CASE_CFN_SINH:
14884 CASE_CFN_SINH_FN:
14885 CASE_CFN_TANH:
14886 CASE_CFN_TANH_FN:
14887 CASE_CFN_TRUNC:
14888 CASE_CFN_TRUNC_FN:
14889 /* True if the 1st argument is nonnegative. */
14892 CASE_CFN_FMAX:
14893 CASE_CFN_FMAX_FN:
14894 /* Usually RECURSE (arg0) || RECURSE (arg1) but NaNs complicate
14895 things. In the presence of sNaNs, we're only guaranteed to be
14896 non-negative if both operands are non-negative. In the presence
14897 of qNaNs, we're non-negative if either operand is non-negative
14898 and can't be a qNaN, or if both operands are non-negative. */
14907 CASE_CFN_FMIN:
14908 CASE_CFN_FMIN_FN:
14909 /* True if the 1st AND 2nd arguments are nonnegative. */
14912 CASE_CFN_COPYSIGN:
14913 CASE_CFN_COPYSIGN_FN:
14914 /* True if the 2nd argument is nonnegative. */
14917 CASE_CFN_POWI:
14918 /* True if the 1st argument is nonnegative or the second
14919 argument is an even integer. */
14925 CASE_CFN_POW:
14926 CASE_CFN_POW_FN:
14927 /* True if the 1st argument is nonnegative or the second
14928 argument is an even integer valued real. */
14930 {
14931 REAL_VALUE_TYPE c;
14932 HOST_WIDE_INT n;
14937 {
14938 REAL_VALUE_TYPE cint;
14942 }
14943 }
14948 }
14950 }
14952 /* Return true if T is known to be non-negative. If the return
14953 value is based on the assumption that signed overflow is undefined,
14954 set *STRICT_OVERFLOW_P to true; otherwise, don't change
14955 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
14957 static bool
14959 {
14965 {
14967 {
14971 /* If the initializer is non-void, then it's a normal expression
14972 that will be assigned to the slot. */
14976 /* Otherwise, the initializer sets the slot in some way. One common
14977 way is an assignment statement at the end of the initializer. */
14979 {
14987 else
14989 }
14995 }
14998 {
15004 arg0,
15005 arg1,
15007 }
15020 }
15021 }
15023 #undef RECURSE
15024 #undef tree_expr_nonnegative_warnv_p
15026 /* Return true if T is known to be non-negative. If the return
15027 value is based on the assumption that signed overflow is undefined,
15028 set *STRICT_OVERFLOW_P to true; otherwise, don't change
15029 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
15031 bool
15033 {
15040 {
15062 }
15065 {
15090 }
15091 }
15093 /* Return true if `t' is known to be non-negative. Handle warnings
15094 about undefined signed overflow. */
15096 bool
15098 {
15105 "determining that expression is always "
15107 WARN_STRICT_OVERFLOW_MISC);
15109 }
15112 /* Return true when (CODE OP0) is an address and is known to be nonzero.
15113 For floating point we further ensure that T is not denormal.
15114 Similar logic is present in nonzero_address in rtlanal.h.
15116 If the return value is based on the assumption that signed overflow
15117 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15118 change *STRICT_OVERFLOW_P. */
15120 bool
15123 {
15125 {
15128 strict_overflow_p);
15131 {
15137 strict_overflow_p));
15138 }
15143 strict_overflow_p);
15147 }
15150 }
15152 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
15153 For floating point we further ensure that T is not denormal.
15154 Similar logic is present in nonzero_address in rtlanal.h.
15156 If the return value is based on the assumption that signed overflow
15157 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15158 change *STRICT_OVERFLOW_P. */
15160 bool
15162 tree type,
15163 tree op0,
15165 {
15168 {
15172 {
15173 /* With the presence of negative values it is hard
15174 to say something. */
15181 /* One of operands must be positive and the other non-negative. */
15182 /* We don't set *STRICT_OVERFLOW_P here: even if this value
15183 overflows, on a twos-complement machine the sum of two
15184 nonnegative numbers can never be zero. */
15186 strict_overflow_p)
15188 strict_overflow_p));
15189 }
15194 {
15196 strict_overflow_p)
15198 strict_overflow_p))
15199 {
15202 }
15203 }
15212 {
15215 }
15222 {
15226 /* When both operands are nonzero, then MAX must be too. */
15228 strict_overflow_p))
15231 /* MAX where operand 0 is positive is positive. */
15233 strict_overflow_p);
15234 }
15235 /* MAX where operand 1 is positive is positive. */
15240 {
15244 }
15249 strict_overflow_p)
15251 strict_overflow_p));
15255 }
15258 }
15260 /* Return true when T is an address and is known to be nonzero.
15261 For floating point we further ensure that T is not denormal.
15262 Similar logic is present in nonzero_address in rtlanal.h.
15264 If the return value is based on the assumption that signed overflow
15265 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
15266 change *STRICT_OVERFLOW_P. */
15268 bool
15270 {
15273 {
15278 {
15290 /* For objects in symbol table check if we know they are non-zero.
15291 Don't do anything for variables and functions before symtab is built;
15292 it is quite possible that they will be declared weak later. */
15297 /* Constants are never weak. */
15302 }
15310 {
15314 }
15324 }
15326 }
15328 #define integer_valued_real_p(X) \
15331 #define RECURSE(X) \
15332 ((integer_valued_real_p) (X, depth + 1))
15334 /* Return true if the floating point result of (CODE OP0) has an
15335 integer value. We also allow +Inf, -Inf and NaN to be considered
15336 integer values. Return false for signaling NaN.
15338 DEPTH is the current nesting depth of the query. */
15340 bool
15342 {
15344 {
15351 CASE_CONVERT:
15352 {
15359 }
15363 }
15365 }
15367 /* Return true if the floating point result of (CODE OP0 OP1) has an
15368 integer value. We also allow +Inf, -Inf and NaN to be considered
15369 integer values. Return false for signaling NaN.
15371 DEPTH is the current nesting depth of the query. */
15373 bool
15375 {
15377 {
15387 }
15389 }
15391 /* Return true if the floating point result of calling FNDECL with arguments
15392 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
15393 considered integer values. Return false for signaling NaN. If FNDECL
15394 takes fewer than 2 arguments, the remaining ARGn are null.
15396 DEPTH is the current nesting depth of the query. */
15398 bool
15400 {
15402 {
15403 CASE_CFN_CEIL:
15404 CASE_CFN_CEIL_FN:
15405 CASE_CFN_FLOOR:
15406 CASE_CFN_FLOOR_FN:
15407 CASE_CFN_NEARBYINT:
15408 CASE_CFN_NEARBYINT_FN:
15409 CASE_CFN_RINT:
15410 CASE_CFN_RINT_FN:
15411 CASE_CFN_ROUND:
15412 CASE_CFN_ROUND_FN:
15413 CASE_CFN_ROUNDEVEN:
15414 CASE_CFN_ROUNDEVEN_FN:
15415 CASE_CFN_TRUNC:
15416 CASE_CFN_TRUNC_FN:
15419 CASE_CFN_FMIN:
15420 CASE_CFN_FMIN_FN:
15421 CASE_CFN_FMAX:
15422 CASE_CFN_FMAX_FN:
15427 }
15429 }
15431 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
15432 has an integer value. We also allow +Inf, -Inf and NaN to be
15433 considered integer values. Return false for signaling NaN.
15435 DEPTH is the current nesting depth of the query. */
15437 bool
15439 {
15441 {
15449 /* Limit the depth of recursion to avoid quadratic behavior.
15450 This is expected to catch almost all occurrences in practice.
15451 If this code misses important cases that unbounded recursion
15452 would not, passes that need this information could be revised
15453 to provide it through dataflow propagation. */
15457 depth));
15461 }
15463 }
15465 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
15466 has an integer value. We also allow +Inf, -Inf and NaN to be
15467 considered integer values. Return false for signaling NaN.
15469 DEPTH is the current nesting depth of the query. */
15471 static bool
15473 {
15475 {
15486 }
15488 }
15490 #undef RECURSE
15491 #undef integer_valued_real_p
15493 /* Return true if the floating point expression T has an integer value.
15494 We also allow +Inf, -Inf and NaN to be considered integer values.
15495 Return false for signaling NaN.
15497 DEPTH is the current nesting depth of the query. */
15499 bool
15501 {
15509 {
15525 }
15528 {
15534 {
15543 }
15547 }
15548 }
15550 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
15551 attempt to fold the expression to a constant without modifying TYPE,
15552 OP0 or OP1.
15554 If the expression could be simplified to a constant, then return
15555 the constant. If the expression would not be simplified to a
15556 constant, then return NULL_TREE. */
15558 tree
15560 {
15563 }
15565 /* Given the components of a unary expression CODE, TYPE and OP0,
15566 attempt to fold the expression to a constant without modifying
15567 TYPE or OP0.
15569 If the expression could be simplified to a constant, then return
15570 the constant. If the expression would not be simplified to a
15571 constant, then return NULL_TREE. */
15573 tree
15575 {
15578 }
15580 /* If EXP represents referencing an element in a constant string
15581 (either via pointer arithmetic or array indexing), return the
15582 tree representing the value accessed, otherwise return NULL. */
15584 tree
15586 {
15590 {
15592 tree index;
15593 tree string;
15598 else
15599 {
15603 /* Optimize the special-case of a zero lower bound.
15605 We convert the low_bound to sizetype to avoid some problems
15606 with constant folding. (E.g. suppose the lower bound is 1,
15607 and its mode is QI. Without the conversion,l (ARRAY
15608 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
15609 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
15615 }
15617 scalar_int_mode char_mode;
15629 }
15631 }
15633 /* Folds a read from vector element at IDX of vector ARG. */
15635 tree
15637 {
15642 {
15646 {
15653 }
15654 }
15656 }
15658 /* Return the tree for neg (ARG0) when ARG0 is known to be either
15659 an integer constant, real, or fixed-point constant.
15661 TYPE is the type of the result. */
15663 static tree
15665 {
15669 {
15675 {
15676 FIXED_VALUE_TYPE f;
15681 /* Propagate overflow flags. */
15685 }
15689 {
15696 }
15699 }
15702 }
15704 /* Return the tree for abs (ARG0) when ARG0 is known to be either
15705 an integer constant or real constant.
15707 TYPE is the type of the result. */
15709 tree
15711 {
15715 {
15717 {
15718 /* If the value is unsigned or non-negative, then the absolute value
15719 is the same as the ordinary value. */
15723 ;
15725 /* If the value is negative, then the absolute value is
15726 its negation. */
15727 else
15730 /* Force to the destination type, set TREE_OVERFLOW for signed
15731 TYPE only. */
15733 }
15739 else
15745 }
15748 }
15750 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
15751 constant. TYPE is the type of the result. */
15753 static tree
15755 {
15759 }
15761 /* Given CODE, a relational operator, the target type, TYPE and two
15762 constant operands OP0 and OP1, return the result of the
15763 relational operation. If the result is not a compile time
15764 constant, then return NULL_TREE. */
15766 static tree
15768 {
15771 /* From here on, the only cases we handle are when the result is
15772 known to be a constant. */
15775 {
15779 /* Handle the cases where either operand is a NaN. */
15781 {
15783 {
15811 }
15814 }
15817 }
15820 {
15824 }
15826 /* Handle equality/inequality of complex constants. */
15828 {
15839 else
15841 }
15844 {
15846 {
15847 /* Have vector comparison with scalar boolean result. */
15855 {
15863 }
15865 }
15866 tree_vector_builder elts;
15871 {
15884 }
15887 }
15889 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
15891 To compute GT, swap the arguments and do LT.
15892 To compute GE, do LT and invert the result.
15893 To compute LE, swap the arguments, do LT and invert the result.
15894 To compute NE, do EQ and invert the result.
15896 Therefore, the code below must handle only EQ and LT. */
15899 {
15902 }
15904 /* Note that it is safe to invert for real values here because we
15905 have already handled the one case that it matters. */
15909 {
15912 }
15914 /* Compute a result for LT or EQ if args permit;
15915 Otherwise return T. */
15917 {
15920 else
15922 }
15923 else
15929 }
15931 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
15932 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
15933 itself. */
15935 tree
15937 {
15938 /* If the expression does not have side effects then we don't have to wrap
15939 it with a cleanup point expression. */
15943 /* If the expression is a return, check to see if the expression inside the
15944 return has no side effects or the right hand side of the modify expression
15945 inside the return. If either don't have side effects set we don't need to
15946 wrap the expression in a cleanup point expression. Note we don't check the
15947 left hand side of the modify because it should always be a return decl. */
15949 {
15956 }
15959 }
15961 /* Given a pointer value OP0 and a type TYPE, return a simplified version
15962 of an indirection through OP0, or NULL_TREE if no simplification is
15963 possible. */
15965 tree
15967 {
15969 tree subtype;
15970 poly_uint64 const_op01;
15979 {
15983 /* *&CONST_DECL -> to the value of the const decl. */
15986 /* *&p => p; make sure to handle *&"str"[cst] here. */
15988 {
15992 else
15994 }
15995 /* *(foo *)&fooarray => fooarray[0] */
15998 && (!in_gimple_form
16000 {
16010 }
16011 /* *(foo *)&complexfoo => __real__ complexfoo */
16015 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
16018 {
16022 index);
16023 }
16024 }
16028 {
16034 {
16035 tree op00type;
16039 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
16042 /* POINTER_PLUS_EXPR second operand is sizetype, unsigned,
16043 but we want to treat offsets with MSB set as negative.
16044 For the code below negative offsets are invalid and
16045 TYPE_SIZE of the element is something unsigned, so
16046 check whether op01 fits into poly_int64, which implies
16047 it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and
16048 then just use poly_uint64 because we want to treat the
16049 value as unsigned. */
16051 {
16053 poly_uint64 max_offset
16057 {
16062 }
16063 }
16064 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
16067 {
16069 const_op01))
16071 }
16072 /* ((foo *)&fooarray)[1] => fooarray[1] */
16075 {
16084 {
16089 }
16090 }
16091 }
16092 }
16094 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
16097 && (!in_gimple_form
16099 {
16100 tree type_domain;
16110 NULL_TREE);
16111 }
16114 }
16116 /* Builds an expression for an indirection through T, simplifying some
16117 cases. */
16119 tree
16121 {
16129 }
16131 /* Given an INDIRECT_REF T, return either T or a simplified version. */
16133 tree
16135 {
16140 else
16142 }
16144 /* Strip non-trapping, non-side-effecting tree nodes from an expression
16145 whose result is ignored. The type of the returned tree need not be
16146 the same as the original expression. */
16148 tree
16150 {
16156 {
16167 else
16173 {
16189 }
16194 }
16195 }
16197 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
16199 tree
16201 {
16207 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16208 have to do anything. Only do this when we are not given a const,
16209 because in that case, this check is more expensive than just
16210 doing it. */
16212 {
16217 }
16219 /* If divisor is a power of two, simplify this to bit manipulation. */
16221 {
16223 {
16237 }
16238 else
16239 {
16240 tree t;
16246 }
16247 }
16248 else
16249 {
16254 }
16257 }
16259 /* Likewise, but round down. */
16261 tree
16263 {
16270 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
16271 have to do anything. Only do this when we are not given a const,
16272 because in that case, this check is more expensive than just
16273 doing it. */
16275 {
16280 }
16282 /* If divisor is a power of two, simplify this to bit manipulation. */
16284 {
16285 tree t;
16289 }
16290 else
16291 {
16296 }
16299 }
16301 /* Returns the pointer to the base of the object addressed by EXP and
16302 extracts the information about the offset of the access, storing it
16303 to PBITPOS and POFFSET. */
16305 static tree
16308 {
16309 tree core;
16310 machine_mode mode;
16312 poly_int64 bitsize;
16321 {
16326 }
16328 {
16334 {
16335 poly_offset_int tem
16341 }
16342 }
16343 else
16344 {
16348 }
16351 }
16353 /* Returns true if addresses of E1 and E2 differ by a constant, false
16354 otherwise. If they do, E1 - E2 is stored in *DIFF. */
16356 bool
16358 {
16373 {
16383 }
16385 {
16386 /* If only one of the offsets is non-constant, the difference cannot
16387 be a constant. */
16389 }
16390 else
16395 }
16397 /* Return OFF converted to a pointer offset type suitable as offset for
16398 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
16399 tree
16401 {
16405 }
16407 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16408 tree
16410 {
16413 }
16415 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
16416 tree
16418 {
16421 }
16423 /* Return a pointer to a NUL-terminated string containing the sequence
16424 of bytes corresponding to the representation of the object referred to
16425 by SRC (or a subsequence of such bytes within it if SRC is a reference
16426 to an initialized constant array plus some constant offset).
16427 Set *STRSIZE the number of bytes in the constant sequence including
16428 the terminating NUL byte. *STRSIZE is equal to sizeof(A) - OFFSET
16429 where A is the array that stores the constant sequence that SRC points
16430 to and OFFSET is the byte offset of SRC from the beginning of A. SRC
16431 need not point to a string or even an array of characters but may point
16432 to an object of any type. */
16436 {
16437 /* The offset into the array A storing the string, and A's byte size. */
16438 tree offset_node;
16439 tree mem_size;
16446 else
16453 {
16456 else
16458 }
16463 /* ARRAY_SIZE is the byte size of the array the constant sequence
16464 is stored in and equal to sizeof A. INIT_BYTES is the number
16465 of bytes in the constant sequence used to initialize the array,
16466 including any embedded NULs as well as the terminating NUL (for
16467 strings), but not including any trailing zeros/NULs past
16468 the terminating one appended implicitly to a string literal to
16469 zero out the remainder of the array it's stored in. For example,
16470 given:
16471 const char a[7] = "abc\0d";
16472 n = strlen (a + 1);
16473 ARRAY_SIZE is 7, INIT_BYTES is 6, and OFFSET is 1. For a valid
16474 (i.e., nul-terminated) string with no embedded nuls, INIT_BYTES
16475 is equal to strlen (A) + 1. */
16480 /* Ideally this would turn into a gcc_checking_assert over time. */
16488 {
16489 /* Compute and store the number of characters from the beginning
16490 of the substring at OFFSET to the end, including the terminating
16491 nul. Offsets past the initial length refer to null strings. */
16494 else
16496 }
16497 else
16498 {
16500 /* Support only properly NUL-terminated single byte strings. */
16505 }
16508 }
16510 /* Return a pointer to a NUL-terminated string corresponding to
16511 the expression STR referencing a constant string, possibly
16512 involving a constant offset. Return null if STR either doesn't
16513 reference a constant string or if it involves a nonconstant
16514 offset. */
16518 {
16520 }
16522 /* Given a tree T, compute which bits in T may be nonzero. */
16524 wide_int
16526 {
16528 {
16546 CASE_CONVERT:
16552 {
16557 }
16561 {
16569 }
16573 {
16581 }
16585 }
16588 }
16590 /* Helper function for address compare simplifications in match.pd.
16591 OP0 and OP1 are ADDR_EXPR operands being compared by CODE.
16592 TYPE is the type of comparison operands.
16593 BASE0, BASE1, OFF0 and OFF1 are set by the function.
16594 GENERIC is true if GENERIC folding and false for GIMPLE folding.
16595 Returns 0 if OP0 is known to be unequal to OP1 regardless of OFF{0,1},
16596 1 if bases are known to be equal and OP0 cmp OP1 depends on OFF0 cmp OFF1,
16597 and 2 if unknown. */
16599 int
16603 {
16613 {
16616 }
16618 {
16621 }
16626 /* Punt in GENERIC on variables with value expressions;
16627 the value expressions might point to fields/elements
16628 of other vars etc. */
16634 {
16638 }
16646 /* Assume different STRING_CSTs with the same content will be
16647 merged. */
16656 {
16659 /* If the offsets are equal we can ignore overflow. */
16662 /* Or if we compare using pointers to decls or strings. */
16667 }
16673 /* At this point we know (or assume) the two pointers point at
16674 different objects. */
16678 /* Punt on non-zero offsets from functions. */
16682 /* Or if the bases are neither decls nor string literals. */
16687 /* For initializers, assume addresses of different functions are
16688 different. */
16694 /* Compute whether one address points to the start of one
16695 object and another one to the end of another one. */
16698 {
16701 else
16703 }
16706 else
16707 {
16711 else
16713 }
16715 {
16718 else
16720 }
16723 else
16724 {
16728 else
16730 }
16732 {
16733 /* If one offset is pointing (or could be) to the beginning of one
16734 object and the other is pointing to one past the last byte of the
16735 other object, punt. */
16740 /* If both offsets are the same, there are some cases we know that are
16741 ok. Either if we know they aren't zero, or if we know both sizes
16742 are no zero. */
16748 }
16750 /* At this point, equal is 2 if either one or both pointers are out of
16751 bounds of their object, or one points to start of its object and the
16752 other points to end of its object. This is unspecified behavior
16753 e.g. in C++. Otherwise equal is 0. */
16757 /* When both pointers point to string literals, even when equal is 0,
16758 due to tail merging of string literals the pointers might be the same. */
16760 {
16767 /* If the bytes in the string literals starting at the pointers
16768 differ, the pointers need to be different. */
16773 {
16778 /* If even the bytes in the string literal before the
16779 pointers are the same, the string literals could be
16780 tail merged. */
16782 }
16784 }
16789 /* If this is a pointer comparison, ignore for now even
16790 valid equalities where one pointer is the offset zero
16791 of one object and the other to one past end of another one. */
16795 /* Assume that string literals can't be adjacent to variables
16796 (automatic or global). */
16800 /* Assume that automatic variables can't be adjacent to global
16801 variables. */
16806 }
16808 /* Return the single non-zero element of a CONSTRUCTOR or NULL_TREE. */
16809 tree
16811 {
16820 {
16824 }
16826 }
16828 #if CHECKING_P
16832 /* Helper functions for writing tests of folding trees. */
16834 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
16836 static void
16838 tree constant)
16839 {
16841 }
16843 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
16844 wrapping WRAPPED_EXPR. */
16846 static void
16848 tree wrapped_expr)
16849 {
16854 }
16856 /* Verify that various arithmetic binary operations are folded
16857 correctly. */
16859 static void
16861 {
16867 /* Addition. */
16868 /* 1 <-- (0 + 1) */
16870 one);
16872 one);
16874 /* (nonlvalue)x <-- (x + 0) */
16876 x);
16878 /* Subtraction. */
16879 /* 0 <-- (x - x) */
16881 zero);
16883 x);
16885 /* Multiplication. */
16886 /* 0 <-- (x * 0) */
16888 zero);
16890 /* (nonlvalue)x <-- (x * 1) */
16892 x);
16893 }
16895 /* Verify that various binary operations on vectors are folded
16896 correctly. */
16898 static void
16900 {
16907 /* Verify equality tests that return a scalar boolean result. */
16920 }
16922 /* Verify folding of VEC_DUPLICATE_EXPRs. */
16924 static void
16926 {
16929 /* This will be 1 if VEC_MODE isn't a vector mode. */
16936 }
16938 /* Run all of the selftests within this file. */
16940 void
16942 {
16946 }