| blob | 1109f5e3bc53f9e9fe238f7d7b4f7914addcafa7 |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2017 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. */
85 /* Nonzero if we are folding constants inside an initializer; zero
86 otherwise. */
89 /* The following constants represent a bit based encoding of GCC's
90 comparison operators. This encoding simplifies transformations
91 on relational comparison operators, such as AND and OR. */
109 };
142 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
143 Otherwise, return LOC. */
145 static location_t
147 {
150 }
152 /* Similar to protected_set_expr_location, but never modify x in place,
153 if location can and needs to be set, unshare it. */
157 {
163 {
166 }
168 }
169 \f
170 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
171 division and returns the quotient. Otherwise returns
172 NULL_TREE. */
174 tree
176 {
177 widest_int quo;
184 }
185 \f
186 /* This is nonzero if we should defer warnings about undefined
187 overflow. This facility exists because these warnings are a
188 special case. The code to estimate loop iterations does not want
189 to issue any warnings, since it works with expressions which do not
190 occur in user code. Various bits of cleanup code call fold(), but
191 only use the result if it has certain characteristics (e.g., is a
192 constant); that code only wants to issue a warning if the result is
193 used. */
197 /* If a warning about undefined overflow is deferred, this is the
198 warning. Note that this may cause us to turn two warnings into
199 one, but that is fine since it is sufficient to only give one
200 warning per expression. */
204 /* If a warning about undefined overflow is deferred, this is the
205 level at which the warning should be emitted. */
209 /* Start deferring overflow warnings. We could use a stack here to
210 permit nested calls, but at present it is not necessary. */
212 void
214 {
216 }
218 /* Stop deferring overflow warnings. If there is a pending warning,
219 and ISSUE is true, then issue the warning if appropriate. STMT is
220 the statement with which the warning should be associated (used for
221 location information); STMT may be NULL. CODE is the level of the
222 warning--a warn_strict_overflow_code value. This function will use
223 the smaller of CODE and the deferred code when deciding whether to
224 issue the warning. CODE may be zero to mean to always use the
225 deferred code. */
227 void
229 {
231 location_t locus;
236 {
242 }
253 /* Use the smallest code level when deciding to issue the
254 warning. */
263 else
266 }
268 /* Stop deferring overflow warnings, ignoring any deferred
269 warnings. */
271 void
273 {
275 }
277 /* Whether we are deferring overflow warnings. */
279 bool
281 {
283 }
285 /* This is called when we fold something based on the fact that signed
286 overflow is undefined. */
288 void
290 {
292 {
295 {
298 }
299 }
302 }
303 \f
304 /* Return true if the built-in mathematical function specified by CODE
305 is odd, i.e. -f(x) == f(-x). */
307 bool
309 {
311 {
312 CASE_CFN_ASIN:
313 CASE_CFN_ASINH:
314 CASE_CFN_ATAN:
315 CASE_CFN_ATANH:
316 CASE_CFN_CASIN:
317 CASE_CFN_CASINH:
318 CASE_CFN_CATAN:
319 CASE_CFN_CATANH:
320 CASE_CFN_CBRT:
321 CASE_CFN_CPROJ:
322 CASE_CFN_CSIN:
323 CASE_CFN_CSINH:
324 CASE_CFN_CTAN:
325 CASE_CFN_CTANH:
326 CASE_CFN_ERF:
327 CASE_CFN_LLROUND:
328 CASE_CFN_LROUND:
329 CASE_CFN_ROUND:
330 CASE_CFN_SIN:
331 CASE_CFN_SINH:
332 CASE_CFN_TAN:
333 CASE_CFN_TANH:
334 CASE_CFN_TRUNC:
337 CASE_CFN_LLRINT:
338 CASE_CFN_LRINT:
339 CASE_CFN_NEARBYINT:
340 CASE_CFN_RINT:
345 }
347 }
349 /* Check whether we may negate an integer constant T without causing
350 overflow. */
352 bool
354 {
355 tree type;
364 }
366 /* Determine whether an expression T can be cheaply negated using
367 the function negate_expr without introducing undefined overflow. */
369 static bool
371 {
372 tree type;
381 {
386 /* Check that -CST will not overflow type. */
399 /* We want to canonicalize to positive real constants. Pretend
400 that only negative ones can be easily negated. */
408 {
419 }
434 /* -(A + B) -> (-B) - A. */
437 /* -(A + B) -> (-A) - B. */
441 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
450 /* INT_MIN/n * n doesn't overflow while negating one operand it does
451 if n is a (negative) power of two. */
462 /* Fall through. */
477 /* In general we can't negate B in A / B, because if A is INT_MIN and
478 B is 1, we may turn this into INT_MIN / -1 which is undefined
479 and actually traps on some architectures. */
488 /* Negate -((double)float) as (double)(-float). */
490 {
494 }
498 /* Negate -f(x) as f(-x). */
504 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
506 {
510 }
515 }
517 }
519 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
520 simplification is possible.
521 If negate_expr_p would return true for T, NULL_TREE will never be
522 returned. */
524 static tree
526 {
528 tree tem;
531 {
532 /* Convert - (~A) to A + 1. */
558 {
563 }
567 {
572 {
577 }
580 }
603 {
604 /* -(A + B) -> (-B) - A. */
606 {
610 }
612 /* -(A + B) -> (-A) - B. */
614 {
618 }
619 }
623 /* - (A - B) -> B - A */
634 /* Fall through. */
638 {
647 }
659 /* In general we can't negate B in A / B, because if A is INT_MIN and
660 B is 1, we may turn this into INT_MIN / -1 which is undefined
661 and actually traps on some architectures. */
673 /* Convert -((double)float) into (double)(-float). */
675 {
679 }
683 /* Negate -f(x) as f(-x). */
686 {
692 }
696 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
698 {
701 {
708 }
709 }
714 }
717 }
719 /* A wrapper for fold_negate_expr_1. */
721 static tree
723 {
730 }
732 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
733 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
734 return NULL_TREE. */
736 static tree
738 {
740 location_t loc;
753 }
754 \f
755 /* Split a tree IN into a constant, literal and variable parts that could be
756 combined with CODE to make IN. "constant" means an expression with
757 TREE_CONSTANT but that isn't an actual constant. CODE must be a
758 commutative arithmetic operation. Store the constant part into *CONP,
759 the literal in *LITP and return the variable part. If a part isn't
760 present, set it to null. If the tree does not decompose in this way,
761 return the entire tree as the variable part and the other parts as null.
763 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
764 case, we negate an operand that was subtracted. Except if it is a
765 literal for which we use *MINUS_LITP instead.
767 If NEGATE_P is true, we are negating all of IN, again except a literal
768 for which we use *MINUS_LITP instead. If a variable part is of pointer
769 type, it is negated after converting to TYPE. This prevents us from
770 generating illegal MINUS pointer expression. LOC is the location of
771 the converted variable part.
773 If IN is itself a literal or constant, return it as appropriate.
775 Note that we do not guarantee that any of the three values will be the
776 same type as IN, but they will have the same signedness and mode. */
778 static tree
782 {
790 /* Strip any conversions that don't change the machine mode or signedness. */
799 /* We can associate addition and subtraction together (even
800 though the C standard doesn't say so) for integers because
801 the value is not affected. For reals, the value might be
802 affected, so we can't. */
808 {
814 /* First see if either of the operands is a literal, then a constant. */
827 /* If we haven't dealt with either operand, this is not a case we can
828 decompose. Otherwise, VAR is either of the ones remaining, if any. */
833 else
836 /* Now do any needed negations. */
843 }
848 {
849 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
850 when IN is constant. */
853 }
854 else
858 {
871 }
881 }
883 /* Re-associate trees split by the above function. T1 and T2 are
884 either expressions to associate or null. Return the new
885 expression, if any. LOC is the location of the new expression. If
886 we build an operation, do it in TYPE and with CODE. */
888 static tree
890 {
892 {
895 }
899 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
900 try to fold this since we will have infinite recursion. But do
901 deal with any NEGATE_EXPRs. */
905 {
907 {
920 }
922 {
925 }
929 }
933 }
934 \f
935 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
936 for use in int_const_binop, size_binop and size_diffop. */
938 static bool
940 {
947 {
956 }
961 }
964 /* Combine two integer constants PARG1 and PARG2 under operation CODE
965 to produce a new constant. Return NULL_TREE if we don't know how
966 to evaluate CODE at compile-time. */
968 static tree
971 {
972 wide_int res;
973 tree t;
982 {
998 {
1002 else
1004 }
1007 /* It's unclear from the C standard whether shifts can overflow.
1008 The following code ignores overflow; perhaps a C standard
1009 interpretation ruling is needed. */
1011 else
1018 {
1022 else
1024 }
1028 else
1107 }
1115 }
1117 tree
1119 {
1121 }
1123 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1124 constant. We assume ARG1 and ARG2 have the same data type, or at least
1125 are the same kind of constant and the same machine mode. Return zero if
1126 combining the constants is not allowed in the current operating mode. */
1128 static tree
1130 {
1131 /* Sanity check for the recursive cases. */
1139 {
1145 }
1148 {
1149 machine_mode mode;
1150 REAL_VALUE_TYPE d1;
1151 REAL_VALUE_TYPE d2;
1152 REAL_VALUE_TYPE value;
1153 REAL_VALUE_TYPE result;
1157 /* The following codes are handled by real_arithmetic. */
1159 {
1170 }
1178 /* Don't perform operation if we honor signaling NaNs and
1179 either operand is a signaling NaN. */
1185 /* Don't perform operation if it would raise a division
1186 by zero exception. */
1192 /* If either operand is a NaN, just return it. Otherwise, set up
1193 for floating-point trap; we return an overflow. */
1195 {
1196 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1197 is off. */
1201 }
1203 {
1204 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1205 is off. */
1209 }
1214 /* Don't constant fold this floating point operation if
1215 the result has overflowed and flag_trapping_math. */
1223 /* Don't constant fold this floating point operation if the
1224 result may dependent upon the run-time rounding mode and
1225 flag_rounding_math is set, or if GCC's software emulation
1226 is unable to accurately represent the result. */
1236 }
1239 {
1240 FIXED_VALUE_TYPE f1;
1241 FIXED_VALUE_TYPE f2;
1242 FIXED_VALUE_TYPE result;
1247 /* The following codes are handled by fixed_arithmetic. */
1249 {
1261 {
1268 }
1273 }
1280 /* Propagate overflow flags. */
1284 }
1287 {
1296 {
1307 mpc_mul);
1321 mpc_div);
1322 /* Fallthru. */
1328 {
1329 /* Keep this algorithm in sync with
1330 tree-complex.c:expand_complex_div_straight().
1332 Expand complex division to scalars, straightforward algorithm.
1333 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1334 t = br*br + bi*bi
1335 */
1336 tree magsquared
1340 tree t1
1344 tree t2
1351 }
1352 else
1353 {
1354 /* Keep this algorithm in sync with
1355 tree-complex.c:expand_complex_div_wide().
1357 Expand complex division to scalars, modified algorithm to minimize
1358 overflow with wide input ranges. */
1364 {
1365 /* In the TRUE branch, we compute
1366 ratio = br/bi;
1367 div = (br * ratio) + bi;
1368 tr = (ar * ratio) + ai;
1369 ti = (ai * ratio) - ar;
1370 tr = tr / div;
1371 ti = ti / div; */
1382 }
1383 else
1384 {
1385 /* In the FALSE branch, we compute
1386 ratio = d/c;
1387 divisor = (d * ratio) + c;
1388 tr = (b * ratio) + a;
1389 ti = b - (a * ratio);
1390 tr = tr / div;
1391 ti = ti / div; */
1403 }
1404 }
1409 }
1413 }
1417 {
1423 {
1429 /* It is possible that const_binop cannot handle the given
1430 code and return NULL_TREE */
1434 }
1437 }
1439 /* Shifts allow a scalar offset for a vector. */
1442 {
1448 {
1453 /* It is possible that const_binop cannot handle the given
1454 code and return NULL_TREE. */
1458 }
1461 }
1463 }
1465 /* Overload that adds a TYPE parameter to be able to dispatch
1466 to fold_relational_const. */
1468 tree
1470 {
1474 /* ??? Until we make the const_binop worker take the type of the
1475 result as argument put those cases that need it here. */
1477 {
1488 {
1502 {
1512 }
1515 }
1521 {
1543 {
1556 }
1559 }
1562 }
1567 /* Make sure type and arg0 have the same saturating flag. */
1572 }
1574 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1575 Return zero if computing the constants is not possible. */
1577 tree
1579 {
1580 /* Don't perform the operation, other than NEGATE and ABS, if
1581 flag_signaling_nans is on and the operand is a signaling NaN. */
1590 {
1591 CASE_CONVERT:
1598 /* If the source address is 0, and the source address space
1599 cannot have a valid object at 0, fold to dest type null. */
1610 {
1611 /* Can't call fold_negate_const directly here as that doesn't
1612 handle all cases and we might not be able to negate some
1613 constants. */
1618 }
1627 {
1631 }
1637 /* Perform BIT_NOT_EXPR on each element individually. */
1639 {
1640 tree elem;
1645 {
1651 }
1654 }
1676 {
1694 else
1699 {
1705 }
1708 }
1713 {
1722 {
1727 }
1731 {
1735 }
1738 }
1742 }
1745 }
1747 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1748 indicates which particular sizetype to create. */
1750 tree
1752 {
1754 }
1755 \f
1756 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1757 is a tree code. The type of the result is taken from the operands.
1758 Both must be equivalent integer types, ala int_binop_types_match_p.
1759 If the operands are constant, so is the result. */
1761 tree
1763 {
1772 /* Handle the special case of two integer constants faster. */
1774 {
1775 /* And some specific cases even faster than that. */
1777 {
1782 }
1784 {
1787 }
1789 {
1792 }
1794 /* Handle general case of two integer constants. For sizetype
1795 constant calculations we always want to know about overflow,
1796 even in the unsigned case. */
1798 }
1801 }
1803 /* Given two values, either both of sizetype or both of bitsizetype,
1804 compute the difference between the two values. Return the value
1805 in signed type corresponding to the type of the operands. */
1807 tree
1809 {
1811 tree ctype;
1816 /* If the type is already signed, just do the simple thing. */
1824 else
1827 /* If either operand is not a constant, do the conversions to the signed
1828 type and subtract. The hardware will do the right thing with any
1829 overflow in the subtraction. */
1835 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1836 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1837 overflow) and negate (which can't either). Special-case a result
1838 of zero while we're here. */
1844 else
1848 MINUS_EXPR,
1850 }
1851 \f
1852 /* A subroutine of fold_convert_const handling conversions of an
1853 INTEGER_CST to another integer type. */
1855 static tree
1857 {
1858 /* Given an integer constant, make new constant with new type,
1859 appropriately sign-extended or truncated. Use widest_int
1860 so that any extension is done according ARG1's type. */
1864 }
1866 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1867 to an integer type. */
1869 static tree
1871 {
1873 tree t;
1875 /* The following code implements the floating point to integer
1876 conversion rules required by the Java Language Specification,
1877 that IEEE NaNs are mapped to zero and values that overflow
1878 the target precision saturate, i.e. values greater than
1879 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1880 are mapped to INT_MIN. These semantics are allowed by the
1881 C and C++ standards that simply state that the behavior of
1882 FP-to-integer conversion is unspecified upon overflow. */
1884 wide_int val;
1885 REAL_VALUE_TYPE r;
1889 {
1896 }
1898 /* If R is NaN, return zero and show we have an overflow. */
1900 {
1903 }
1905 /* See if R is less than the lower bound or greater than the
1906 upper bound. */
1909 {
1913 {
1916 }
1917 }
1920 {
1923 {
1926 {
1929 }
1930 }
1931 }
1938 }
1940 /* A subroutine of fold_convert_const handling conversions of a
1941 FIXED_CST to an integer type. */
1943 static tree
1945 {
1946 tree t;
1948 scalar_mode mode;
1950 /* Right shift FIXED_CST to temp by fbit. */
1954 {
1956 HOST_BITS_PER_DOUBLE_INT,
1959 /* Left shift temp to temp_trunc by fbit. */
1961 HOST_BITS_PER_DOUBLE_INT,
1963 }
1964 else
1965 {
1968 }
1970 /* If FIXED_CST is negative, we need to round the value toward 0.
1971 By checking if the fractional bits are not zero to add 1 to temp. */
1977 /* Given a fixed-point constant, make new constant with new type,
1978 appropriately sign-extended or truncated. */
1986 }
1988 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1989 to another floating point type. */
1991 static tree
1993 {
1994 REAL_VALUE_TYPE value;
1995 tree t;
1997 /* Don't perform the operation if flag_signaling_nans is on
1998 and the operand is a signaling NaN. */
2006 /* If converting an infinity or NAN to a representation that doesn't
2007 have one, set the overflow bit so that we can produce some kind of
2008 error message at the appropriate point if necessary. It's not the
2009 most user-friendly message, but it's better than nothing. */
2016 /* Regular overflow, conversion produced an infinity in a mode that
2017 can't represent them. */
2022 else
2025 }
2027 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2028 to a floating point type. */
2030 static tree
2032 {
2033 REAL_VALUE_TYPE value;
2034 tree t;
2042 }
2044 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2045 to another fixed-point type. */
2047 static tree
2049 {
2050 FIXED_VALUE_TYPE value;
2051 tree t;
2058 /* Propagate overflow flags. */
2062 }
2064 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2065 to a fixed-point type. */
2067 static tree
2069 {
2070 FIXED_VALUE_TYPE value;
2071 tree t;
2073 double_int di;
2080 else
2088 /* Propagate overflow flags. */
2092 }
2094 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2095 to a fixed-point type. */
2097 static tree
2099 {
2100 FIXED_VALUE_TYPE value;
2101 tree t;
2109 /* Propagate overflow flags. */
2113 }
2115 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2116 type TYPE. If no simplification can be done return NULL_TREE. */
2118 static tree
2120 {
2126 {
2133 }
2135 {
2142 }
2144 {
2151 }
2153 {
2156 {
2161 {
2167 }
2169 }
2170 }
2172 }
2174 /* Construct a vector of zero elements of vector type TYPE. */
2176 static tree
2178 {
2179 tree t;
2183 }
2185 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2187 bool
2189 {
2204 {
2219 }
2220 }
2222 /* Convert expression ARG to type TYPE. Used by the middle-end for
2223 simple conversions in preference to calling the front-end's convert. */
2225 tree
2227 {
2229 tree tem;
2240 {
2243 /* Handle conversions between pointers to different address spaces. */
2248 /* fall through */
2253 {
2257 }
2271 {
2275 }
2277 {
2281 }
2283 {
2287 }
2290 {
2308 }
2313 {
2317 }
2320 {
2334 }
2338 {
2347 integer_zero_node));
2349 {
2353 {
2359 }
2367 }
2371 }
2389 }
2390 fold_convert_exit:
2393 }
2394 \f
2395 /* Return false if expr can be assumed not to be an lvalue, true
2396 otherwise. */
2398 static bool
2400 {
2401 /* We only need to wrap lvalue tree codes. */
2403 {
2434 /* Assume the worst for front-end tree codes. */
2438 }
2441 }
2443 /* Return an expr equal to X but certainly not valid as an lvalue. */
2445 tree
2447 {
2448 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2449 us. */
2456 }
2458 /* When pedantic, return an expr equal to X but certainly not valid as a
2459 pedantic lvalue. Otherwise, return X. */
2461 static tree
2463 {
2465 }
2466 \f
2467 /* Given a tree comparison code, return the code that is the logical inverse.
2468 It is generally not safe to do this for floating-point comparisons, except
2469 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2470 ERROR_MARK in this case. */
2472 enum tree_code
2474 {
2480 {
2511 }
2512 }
2514 /* Similar, but return the comparison that results if the operands are
2515 swapped. This is safe for floating-point. */
2517 enum tree_code
2519 {
2521 {
2547 }
2548 }
2551 /* Convert a comparison tree code from an enum tree_code representation
2552 into a compcode bit-based encoding. This function is the inverse of
2553 compcode_to_comparison. */
2555 static enum comparison_code
2557 {
2559 {
2590 }
2591 }
2593 /* Convert a compcode bit-based encoding of a comparison operator back
2594 to GCC's enum tree_code representation. This function is the
2595 inverse of comparison_to_compcode. */
2597 static enum tree_code
2599 {
2601 {
2632 }
2633 }
2635 /* Return a tree for the comparison which is the combination of
2636 doing the AND or OR (depending on CODE) of the two operations LCODE
2637 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2638 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2639 if this makes the transformation invalid. */
2641 tree
2646 {
2653 {
2664 }
2667 {
2668 /* Eliminate unordered comparisons, as well as LTGT and ORD
2669 which are not used unless the mode has NaNs. */
2675 }
2677 {
2678 /* Check that the original operation and the optimized ones will trap
2679 under the same condition. */
2690 /* In a short-circuited boolean expression the LHS might be
2691 such that the RHS, if evaluated, will never trap. For
2692 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2693 if neither x nor y is NaN. (This is a mixed blessing: for
2694 example, the expression above will never trap, hence
2695 optimizing it to x < y would be invalid). */
2700 /* If the comparison was short-circuited, and only the RHS
2701 trapped, we may now generate a spurious trap. */
2706 /* If we changed the conditions that cause a trap, we lose. */
2709 }
2715 else
2716 {
2721 }
2722 }
2723 \f
2724 /* Return nonzero if two operands (typically of the same tree node)
2725 are necessarily equal. FLAGS modifies behavior as follows:
2727 If OEP_ONLY_CONST is set, only return nonzero for constants.
2728 This function tests whether the operands are indistinguishable;
2729 it does not test whether they are equal using C's == operation.
2730 The distinction is important for IEEE floating point, because
2731 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2732 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2734 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2735 even though it may hold multiple values during a function.
2736 This is because a GCC tree node guarantees that nothing else is
2737 executed between the evaluation of its "operands" (which may often
2738 be evaluated in arbitrary order). Hence if the operands themselves
2739 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2740 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2741 unset means assuming isochronic (or instantaneous) tree equivalence.
2742 Unless comparing arbitrary expression trees, such as from different
2743 statements, this flag can usually be left unset.
2745 If OEP_PURE_SAME is set, then pure functions with identical arguments
2746 are considered the same. It is used when the caller has other ways
2747 to ensure that global memory is unchanged in between.
2749 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2750 not values of expressions.
2752 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2753 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2755 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2756 any operand with side effect. This is unnecesarily conservative in the
2757 case we know that arg0 and arg1 are in disjoint code paths (such as in
2758 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2759 addresses with TREE_CONSTANT flag set so we know that &var == &var
2760 even if var is volatile. */
2762 int
2764 {
2765 /* When checking, verify at the outermost operand_equal_p call that
2766 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2767 hash value. */
2769 {
2771 {
2773 {
2780 }
2782 }
2783 else
2785 }
2787 /* If either is ERROR_MARK, they aren't equal. */
2793 /* Similar, if either does not have a type (like a released SSA name),
2794 they aren't equal. */
2798 /* We cannot consider pointers to different address space equal. */
2805 /* Check equality of integer constants before bailing out due to
2806 precision differences. */
2808 {
2809 /* Address of INTEGER_CST is not defined; check that we did not forget
2810 to drop the OEP_ADDRESS_OF flags. */
2813 }
2816 {
2817 /* If both types don't have the same signedness, then we can't consider
2818 them equal. We must check this before the STRIP_NOPS calls
2819 because they may change the signedness of the arguments. As pointers
2820 strictly don't have a signedness, require either two pointers or
2821 two non-pointers as well. */
2827 /* If both types don't have the same precision, then it is not safe
2828 to strip NOPs. */
2835 }
2836 #if 0
2837 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2838 sanity check once the issue is solved. */
2839 else
2840 /* Addresses of conversions and SSA_NAMEs (and many other things)
2841 are not defined. Check that we did not forget to drop the
2842 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2845 #endif
2847 /* In case both args are comparisons but with different comparison
2848 code, try to swap the comparison operands of one arg to produce
2849 a match and compare that variant. */
2853 {
2861 }
2864 {
2865 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2867 ;
2869 {
2870 /* If we are interested in comparing addresses ignore
2871 MEM_REF wrappings of the base that can appear just for
2872 TBAA reasons. */
2886 }
2887 else
2889 }
2891 /* When not checking adddresses, this is needed for conversions and for
2892 COMPONENT_REF. Might as well play it safe and always test this. */
2899 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2900 We don't care about side effects in that case because the SAVE_EXPR
2901 takes care of that for us. In all other cases, two expressions are
2902 equal if they have no side effects. If we have two identical
2903 expressions with side effects that should be treated the same due
2904 to the only side effects being identical SAVE_EXPR's, that will
2905 be detected in the recursive calls below.
2906 If we are taking an invariant address of two identical objects
2907 they are necessarily equal as well. */
2914 /* Next handle constant cases, those for which we can return 1 even
2915 if ONLY_CONST is set. */
2918 {
2932 {
2933 /* If we do not distinguish between signed and unsigned zero,
2934 consider them equal. */
2937 }
2941 {
2948 {
2952 }
2954 }
2958 flags)
2960 flags));
2971 flags | OEP_ADDRESS_OF
2974 /* In GIMPLE empty constructors are allowed in initializers of
2975 aggregates. */
2979 }
2984 /* Define macros to test an operand from arg0 and arg1 for equality and a
2985 variant that allows null and views null as being different from any
2986 non-null value. In the latter case, if either is null, the both
2987 must be; otherwise, do the normal comparison. */
2988 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2989 TREE_OPERAND (arg1, N), flags)
2991 #define OP_SAME_WITH_NULL(N) \
2992 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2993 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2996 {
2998 /* Two conversions are equal only if signedness and modes match. */
3000 {
3001 CASE_CONVERT:
3009 }
3019 /* For commutative ops, allow the other order. */
3027 /* If either of the pointer (or reference) expressions we are
3028 dereferencing contain a side effect, these cannot be equal,
3029 but their addresses can be. */
3036 {
3046 /* Require the same offset. */
3052 /* Fallthru. */
3060 {
3061 /* Require equal access sizes */
3067 flags)))
3069 /* Verify that access happens in similar types. */
3072 /* Verify that accesses are TBAA compatible. */
3081 /* Verify that alignment is compatible. */
3085 }
3088 /* TARGET_MEM_REF require equal extra operands. */
3099 /* Compare the array index by value if it is constant first as we
3100 may have different types but same value here. */
3106 /* Compare low bound and element size as with OEP_ADDRESS_OF
3107 we have to account for the offset of the ref. */
3112 array_ref_low_bound
3116 array_ref_element_size
3118 flags))));
3121 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3122 may be NULL when we're called to compare MEM_EXPRs. */
3137 }
3141 {
3143 /* Be sure we pass right ADDRESS_OF flag. */
3161 /* The multiplcation operands are commutative. */
3162 /* FALLTHRU */
3170 /* Otherwise take into account this is a commutative operation. */
3183 /* BIT_INSERT_EXPR has an implict operand as the type precision
3184 of op1. Need to check to make sure they are the same. */
3190 /* FALLTHRU */
3215 }
3219 {
3223 /* If not both CALL_EXPRs are either internal or normal function
3224 functions, then they are not equal. */
3227 {
3228 /* If the CALL_EXPRs call different internal functions, then they
3229 are not equal. */
3232 }
3233 else
3234 {
3235 /* If the CALL_EXPRs call different functions, then they are not
3236 equal. */
3238 flags))
3240 }
3242 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3243 {
3247 else
3251 }
3253 /* Now see if all the arguments are the same. */
3254 {
3265 /* If we get here and both argument lists are exhausted
3266 then the CALL_EXPRs are equal. */
3268 }
3271 }
3274 /* Consider __builtin_sqrt equal to sqrt. */
3282 {
3283 /* In GIMPLE constructors are used only to build vectors from
3284 elements. Individual elements in the constructor must be
3285 indexed in increasing order and form an initial sequence.
3287 We make no effort to compare constructors in generic.
3288 (see sem_variable::equals in ipa-icf which can do so for
3289 constants). */
3294 /* Be sure that vectors constructed have the same representation.
3295 We only tested element precision and modes to match.
3296 Vectors may be BLKmode and thus also check that the number of
3297 parts match. */
3310 {
3315 /* In GIMPLE the indexes can be either NULL or matching i.
3316 Double check this so we won't get false
3317 positives for GENERIC. */
3325 }
3327 }
3330 {
3331 /* Compare the STATEMENT_LISTs. */
3337 {
3338 /* The lists don't have the same number of statements. */
3344 OEP_LEXICOGRAPHIC))
3346 }
3347 }
3352 {
3359 }
3363 }
3365 #undef OP_SAME
3366 #undef OP_SAME_WITH_NULL
3367 }
3368 \f
3369 /* Similar to operand_equal_p, but see if ARG0 might be a variant of ARG1
3370 with a different signedness or a narrower precision. */
3372 static bool
3374 {
3382 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3383 and see if the inner values are the same. This removes any
3384 signedness comparison, which doesn't matter here. */
3392 /* Discard a single widening conversion from ARG1 and see if the inner
3393 value is the same as ARG0. */
3402 }
3403 \f
3404 /* See if ARG is an expression that is either a comparison or is performing
3405 arithmetic on comparisons. The comparisons must only be comparing
3406 two different values, which will be stored in *CVAL1 and *CVAL2; if
3407 they are nonzero it means that some operands have already been found.
3408 No variables may be used anywhere else in the expression except in the
3409 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3410 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3412 If this is true, return 1. Otherwise, return zero. */
3414 static int
3416 {
3420 /* We can handle some of the tcc_expression cases here. */
3430 {
3431 /* If we've already found a CVAL1 or CVAL2, this expression is
3432 two complex to handle. */
3438 }
3441 {
3464 /* First see if we can handle the first operand, then the second. For
3465 the second operand, we know *CVAL1 can't be zero. It must be that
3466 one side of the comparison is each of the values; test for the
3467 case where this isn't true by failing if the two operands
3468 are the same. */
3477 ;
3481 ;
3482 else
3486 ;
3490 ;
3491 else
3498 }
3499 }
3500 \f
3501 /* ARG is a tree that is known to contain just arithmetic operations and
3502 comparisons. Evaluate the operations in the tree substituting NEW0 for
3503 any occurrence of OLD0 as an operand of a comparison and likewise for
3504 NEW1 and OLD1. */
3506 static tree
3509 {
3514 /* We can handle some of the tcc_expression cases here. */
3522 {
3537 {
3556 }
3557 /* Fall through - ??? */
3560 {
3564 /* We need to check both for exact equality and tree equality. The
3565 former will be true if the operand has a side-effect. In that
3566 case, we know the operand occurred exactly once. */
3579 }
3583 }
3584 }
3585 \f
3586 /* Return a tree for the case when the result of an expression is RESULT
3587 converted to TYPE and OMITTED was previously an operand of the expression
3588 but is now not needed (e.g., we folded OMITTED * 0).
3590 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3591 the conversion of RESULT to TYPE. */
3593 tree
3595 {
3598 /* If the resulting operand is an empty statement, just return the omitted
3599 statement casted to void. */
3609 }
3611 /* Return a tree for the case when the result of an expression is RESULT
3612 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3613 of the expression but are now not needed.
3615 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3616 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3617 evaluated before OMITTED2. Otherwise, if neither has side effects,
3618 just do the conversion of RESULT to TYPE. */
3620 tree
3623 {
3632 }
3634 \f
3635 /* Return a simplified tree node for the truth-negation of ARG. This
3636 never alters ARG itself. We assume that ARG is an operation that
3637 returns a truth value (0 or 1).
3639 FIXME: one would think we would fold the result, but it causes
3640 problems with the dominator optimizer. */
3642 static tree
3644 {
3649 /* If this is a comparison, we can simply invert it, except for
3650 floating-point non-equality comparisons, in which case we just
3651 enclose a TRUTH_NOT_EXPR around what we have. */
3654 {
3657 && flag_trapping_math
3671 }
3674 {
3693 /* Here we can invert either operand. We invert the first operand
3694 unless the second operand is a TRUTH_NOT_EXPR in which case our
3695 result is the XOR of the first operand with the inside of the
3696 negation of the second operand. */
3701 else
3724 {
3731 /* A COND_EXPR may have a throw as one operand, which
3732 then has void type. Just leave void operands
3733 as they are. */
3739 }
3751 CASE_CONVERT:
3755 /* fall through */
3777 }
3778 }
3780 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3781 assume that ARG is an operation that returns a truth value (0 or 1
3782 for scalars, 0 or -1 for vectors). Return the folded expression if
3783 folding is successful. Otherwise, return NULL_TREE. */
3785 static tree
3787 {
3790 ? BIT_NOT_EXPR
3793 }
3795 /* Return a simplified tree node for the truth-negation of ARG. This
3796 never alters ARG itself. We assume that ARG is an operation that
3797 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3799 tree
3801 {
3807 ? BIT_NOT_EXPR
3810 }
3811 \f
3812 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3813 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3814 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3815 is the original memory reference used to preserve the alias set of
3816 the access. */
3818 static tree
3822 {
3825 /* Attempt not to lose the access path if possible. */
3827 {
3829 machine_mode nmode;
3831 tree noffset;
3841 && !reversep
3842 && !nreversep
3844 {
3847 }
3848 }
3857 {
3864 }
3879 }
3881 /* Optimize a bit-field compare.
3883 There are two cases: First is a compare against a constant and the
3884 second is a comparison of two items where the fields are at the same
3885 bit position relative to the start of a chunk (byte, halfword, word)
3886 large enough to contain it. In these cases we can avoid the shift
3887 implicit in bitfield extractions.
3889 For constants, we emit a compare of the shifted constant with the
3890 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3891 compared. For two fields at the same position, we do the ANDs with the
3892 similar mask and compare the result of the ANDs.
3894 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3895 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3896 are the left and right operands of the comparison, respectively.
3898 If the optimization described above can be done, we return the resulting
3899 tree. Otherwise we return zero. */
3901 static tree
3904 {
3907 tree unsigned_type;
3910 scalar_int_mode nmode;
3915 tree mask;
3916 tree offset;
3918 /* Get all the information about the extractions being done. If the bit size
3919 if the same as the size of the underlying object, we aren't doing an
3920 extraction at all and so can do nothing. We also don't want to
3921 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3922 then will no longer be able to replace it. */
3931 else
3932 {
3933 /* If this is not a constant, we can only do something if bit positions,
3934 sizes, signedness and storage order are the same. */
3935 rinner
3943 }
3945 /* Honor the C++ memory model and mimic what RTL expansion does. */
3949 {
3953 }
3955 /* See if we can find a mode to refer to this field. We should be able to,
3956 but fail if we can't. */
3964 /* Set signed and unsigned types of the precision of this mode for the
3965 shifts below. */
3968 /* Compute the bit position and size for the new reference and our offset
3969 within it. If the new reference is the same size as the original, we
3970 won't optimize anything, so return zero. */
3980 /* Make the mask to be used against the extracted field. */
3987 {
3991 /* If not comparing with constant, just rework the comparison
3992 and return. */
4000 }
4002 /* Otherwise, we are handling the constant case. See if the constant is too
4003 big for the field. Warn and return a tree for 0 (false) if so. We do
4004 this not only for its own sake, but to avoid having to test for this
4005 error case below. If we didn't, we might generate wrong code.
4007 For unsigned fields, the constant shifted right by the field length should
4008 be all zero. For signed fields, the high-order bits should agree with
4009 the sign bit. */
4012 {
4014 {
4018 }
4019 }
4020 else
4021 {
4024 {
4028 }
4029 }
4034 /* Single-bit compares should always be against zero. */
4036 {
4039 }
4041 /* Make a new bitfield reference, shift the constant over the
4042 appropriate number of bits and mask it with the computed mask
4043 (in case this was a signed field). If we changed it, make a new one. */
4051 mask);
4056 }
4057 \f
4058 /* Subroutine for fold_truth_andor_1: decode a field reference.
4060 If EXP is a comparison reference, we return the innermost reference.
4062 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4063 set to the starting bit number.
4065 If the innermost field can be completely contained in a mode-sized
4066 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4068 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4069 otherwise it is not changed.
4071 *PUNSIGNEDP is set to the signedness of the field.
4073 *PREVERSEP is set to the storage order of the field.
4075 *PMASK is set to the mask used. This is either contained in a
4076 BIT_AND_EXPR or derived from the width of the field.
4078 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4080 Return 0 if this is not a component reference or is one that we can't
4081 do anything with. */
4083 static tree
4088 {
4093 tree unsigned_type;
4096 /* All the optimizations using this function assume integer fields.
4097 There are problems with FP fields since the type_for_size call
4098 below can fail for, e.g., XFmode. */
4102 /* We are interested in the bare arrangement of bits, so strip everything
4103 that doesn't affect the machine mode. However, record the type of the
4104 outermost expression if it may matter below. */
4111 {
4117 }
4124 /* Reject out-of-bound accesses (PR79731). */
4132 /* If the number of bits in the reference is the same as the bitsize of
4133 the outer type, then the outer type gives the signedness. Otherwise
4134 (in case of a small bitfield) the signedness is unchanged. */
4138 /* Compute the mask to access the bitfield. */
4147 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4155 }
4157 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4158 bit positions and MASK is SIGNED. */
4160 static int
4162 {
4166 /* If this function returns true when the type of the mask is
4167 UNSIGNED, then there will be errors. In particular see
4168 gcc.c-torture/execute/990326-1.c. There does not appear to be
4169 any documentation paper trail as to why this is so. But the pre
4170 wide-int worked with that restriction and it has been preserved
4171 here. */
4176 }
4178 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4179 represents the sign bit of EXP's type. If EXP represents a sign
4180 or zero extension, also test VAL against the unextended type.
4181 The return value is the (sub)expression whose sign bit is VAL,
4182 or NULL_TREE otherwise. */
4184 tree
4186 {
4188 tree t;
4190 /* Tree EXP must have an integral type. */
4195 /* Tree VAL must be an integer constant. */
4204 /* Handle extension from a narrower type. */
4210 }
4212 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4213 to be evaluated unconditionally. */
4215 static int
4217 {
4218 /* Strip any conversions that don't change the machine mode. */
4227 /* Don't regard global variables as simple. They may be
4228 allocated in ways unknown to the compiler (shared memory,
4229 #pragma weak, etc). */
4232 /* Weakrefs are not safe to be read, since they can be NULL.
4233 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4234 have DECL_WEAK flag set. */
4236 /* Loading a static variable is unduly expensive, but global
4237 registers aren't expensive. */
4239 }
4241 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4242 to be evaluated unconditionally.
4243 I addition to simple_operand_p, we assume that comparisons, conversions,
4244 and logic-not operations are simple, if their operands are simple, too. */
4246 static bool
4248 {
4268 }
4270 \f
4271 /* The following functions are subroutines to fold_range_test and allow it to
4272 try to change a logical combination of comparisons into a range test.
4274 For example, both
4275 X == 2 || X == 3 || X == 4 || X == 5
4276 and
4277 X >= 2 && X <= 5
4278 are converted to
4279 (unsigned) (X - 2) <= 3
4281 We describe each set of comparisons as being either inside or outside
4282 a range, using a variable named like IN_P, and then describe the
4283 range with a lower and upper bound. If one of the bounds is omitted,
4284 it represents either the highest or lowest value of the type.
4286 In the comments below, we represent a range by two numbers in brackets
4287 preceded by a "+" to designate being inside that range, or a "-" to
4288 designate being outside that range, so the condition can be inverted by
4289 flipping the prefix. An omitted bound is represented by a "-". For
4290 example, "- [-, 10]" means being outside the range starting at the lowest
4291 possible value and ending at 10, in other words, being greater than 10.
4292 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4293 always false.
4295 We set up things so that the missing bounds are handled in a consistent
4296 manner so neither a missing bound nor "true" and "false" need to be
4297 handled using a special case. */
4299 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4300 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4301 and UPPER1_P are nonzero if the respective argument is an upper bound
4302 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4303 must be specified for a comparison. ARG1 will be converted to ARG0's
4304 type if both are specified. */
4306 static tree
4309 {
4310 tree tem;
4314 /* If neither arg represents infinity, do the normal operation.
4315 Else, if not a comparison, return infinity. Else handle the special
4316 comparison rules. Note that most of the cases below won't occur, but
4317 are handled for consistency. */
4320 {
4325 }
4330 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4331 for neither. In real maths, we cannot assume open ended ranges are
4332 the same. But, this is computer arithmetic, where numbers are finite.
4333 We can therefore make the transformation of any unbounded range with
4334 the value Z, Z being greater than any representable number. This permits
4335 us to treat unbounded ranges as equal. */
4339 {
4360 }
4363 }
4364 \f
4365 /* Helper routine for make_range. Perform one step for it, return
4366 new expression if the loop should continue or NULL_TREE if it should
4367 stop. */
4369 tree
4373 {
4379 {
4381 /* We can only do something if the range is testing for zero. */
4390 /* We can only do something if the range is testing for zero
4391 and if the second operand is an integer constant. Note that
4392 saying something is "in" the range we make is done by
4393 complementing IN_P since it will set in the initial case of
4394 being not equal to zero; "out" is leaving it alone. */
4401 {
4422 }
4424 /* If this is an unsigned comparison, we also know that EXP is
4425 greater than or equal to zero. We base the range tests we make
4426 on that fact, so we record it here so we can parse existing
4427 range tests. We test arg0_type since often the return type
4428 of, e.g. EQ_EXPR, is boolean. */
4430 {
4434 NULL_TREE))
4439 /* If the high bound is missing, but we have a nonzero low
4440 bound, reverse the range so it goes from zero to the low bound
4441 minus 1. */
4443 {
4448 }
4449 }
4457 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4458 low and high are non-NULL, then normalize will DTRT. */
4461 {
4466 }
4468 /* (-x) IN [a,b] -> x in [-b, -a] */
4480 /* ~ X -> -X - 1 */
4489 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4490 move a constant to the other side. */
4495 /* If EXP is signed, any overflow in the computation is undefined,
4496 so we don't worry about it so long as our computations on
4497 the bounds don't overflow. For unsigned, overflow is defined
4498 and this is exactly the right thing. */
4510 normalize:
4511 /* Check for an unsigned range which has wrapped around the maximum
4512 value thus making n_high < n_low, and normalize it. */
4514 {
4520 /* If the range is of the form +/- [ x+1, x ], we won't
4521 be able to normalize it. But then, it represents the
4522 whole range or the empty set, so make it
4523 +/- [ -, - ]. */
4527 else
4529 }
4530 else
4538 CASE_CONVERT:
4556 /* If we're converting arg0 from an unsigned type, to exp,
4557 a signed type, we will be doing the comparison as unsigned.
4558 The tests above have already verified that LOW and HIGH
4559 are both positive.
4561 So we have to ensure that we will handle large unsigned
4562 values the same way that the current signed bounds treat
4563 negative values. */
4566 {
4567 tree high_positive;
4568 tree equiv_type;
4569 /* For fixed-point modes, we need to pass the saturating flag
4570 as the 2nd parameter. */
4572 equiv_type
4575 else
4576 equiv_type
4579 /* A range without an upper bound is, naturally, unbounded.
4580 Since convert would have cropped a very large value, use
4581 the max value for the destination type. */
4582 high_positive
4589 high_positive),
4592 /* If the low bound is specified, "and" the range with the
4593 range for which the original unsigned value will be
4594 positive. */
4596 {
4599 integer_zero_node),
4600 high_positive))
4604 }
4605 else
4606 {
4607 /* Otherwise, "or" the range with the range of the input
4608 that will be interpreted as negative. */
4611 integer_zero_node),
4612 high_positive))
4616 }
4617 }
4626 }
4627 }
4629 /* Given EXP, a logical expression, set the range it is testing into
4630 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4631 actually being tested. *PLOW and *PHIGH will be made of the same
4632 type as the returned expression. If EXP is not a comparison, we
4633 will most likely not be returning a useful value and range. Set
4634 *STRICT_OVERFLOW_P to true if the return value is only valid
4635 because signed overflow is undefined; otherwise, do not change
4636 *STRICT_OVERFLOW_P. */
4638 tree
4641 {
4649 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4650 and see if we can refine the range. Some of the cases below may not
4651 happen, but it doesn't seem worth worrying about this. We "continue"
4652 the outer loop when we've changed something; otherwise we "break"
4653 the switch, which will "break" the while. */
4659 {
4665 {
4673 }
4682 }
4684 /* If EXP is a constant, we can evaluate whether this is true or false. */
4686 {
4693 }
4697 }
4699 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4700 a bitwise check i.e. when
4701 LOW == 0xXX...X00...0
4702 HIGH == 0xXX...X11...1
4703 Return corresponding mask in MASK and stem in VALUE. */
4705 static bool
4708 {
4731 }
4732 \f
4733 /* Helper routine for build_range_check and match.pd. Return the type to
4734 perform the check or NULL if it shouldn't be optimized. */
4736 tree
4738 {
4739 /* First make sure that arithmetics in this type is valid, then make sure
4740 that it wraps around. */
4746 {
4749 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4750 for the type in question, as we rely on this here. */
4760 else
4762 }
4764 }
4766 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4767 type, TYPE, return an expression to test if EXP is in (or out of, depending
4768 on IN_P) the range. Return 0 if the test couldn't be created. */
4770 tree
4773 {
4776 /* Disable this optimization for function pointer expressions
4777 on targets that require function pointer canonicalization. */
4784 {
4790 }
4812 value);
4815 {
4817 {
4821 }
4823 }
4825 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4827 {
4831 {
4833 {
4836 etype
4838 else
4841 }
4844 }
4845 }
4847 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4848 This requires wrap-around arithmetics for the type of the expression. */
4868 }
4869 \f
4870 /* Return the predecessor of VAL in its type, handling the infinite case. */
4872 static tree
4874 {
4880 else
4883 }
4885 /* Return the successor of VAL in its type, handling the infinite case. */
4887 static tree
4889 {
4895 else
4898 }
4900 /* Given two ranges, see if we can merge them into one. Return 1 if we
4901 can, 0 if we can't. Set the output range into the specified parameters. */
4903 bool
4906 {
4910 tree tem;
4920 /* Make range 0 be the range that starts first, or ends last if they
4921 start at the same value. Swap them if it isn't. */
4924 || (lowequal
4927 {
4931 }
4933 /* Now flag two cases, whether the ranges are disjoint or whether the
4934 second range is totally subsumed in the first. Note that the tests
4935 below are simplified by the ones above. */
4941 /* We now have four cases, depending on whether we are including or
4942 excluding the two ranges. */
4944 {
4945 /* If they don't overlap, the result is false. If the second range
4946 is a subset it is the result. Otherwise, the range is from the start
4947 of the second to the end of the first. */
4952 else
4954 }
4957 {
4958 /* If they don't overlap, the result is the first range. If they are
4959 equal, the result is false. If the second range is a subset of the
4960 first, and the ranges begin at the same place, we go from just after
4961 the end of the second range to the end of the first. If the second
4962 range is not a subset of the first, or if it is a subset and both
4963 ranges end at the same place, the range starts at the start of the
4964 first range and ends just before the second range.
4965 Otherwise, we can't describe this as a single range. */
4971 {
4976 {
4977 /* We are in the weird situation where high0 > high1 but
4978 high1 has no successor. Punt. */
4980 }
4981 }
4983 {
4988 {
4989 /* low0 < low1 but low1 has no predecessor. Punt. */
4991 }
4992 }
4993 else
4995 }
4998 {
4999 /* If they don't overlap, the result is the second range. If the second
5000 is a subset of the first, the result is false. Otherwise,
5001 the range starts just after the first range and ends at the
5002 end of the second. */
5007 else
5008 {
5013 {
5014 /* high1 > high0 but high0 has no successor. Punt. */
5016 }
5017 }
5018 }
5020 else
5021 {
5022 /* The case where we are excluding both ranges. Here the complex case
5023 is if they don't overlap. In that case, the only time we have a
5024 range is if they are adjacent. If the second is a subset of the
5025 first, the result is the first. Otherwise, the range to exclude
5026 starts at the beginning of the first range and ends at the end of the
5027 second. */
5029 {
5034 else
5035 {
5036 /* Canonicalize - [min, x] into - [-, x]. */
5039 {
5044 /* FALLTHROUGH */
5057 }
5059 /* Canonicalize - [x, max] into - [x, -]. */
5062 {
5067 /* FALLTHROUGH */
5083 }
5085 /* The ranges might be also adjacent between the maximum and
5086 minimum values of the given type. For
5087 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5088 return + [x + 1, y - 1]. */
5090 {
5097 }
5098 else
5100 }
5101 }
5104 else
5106 }
5110 }
5111 \f
5113 /* Subroutine of fold, looking inside expressions of the form
5114 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5115 of the COND_EXPR. This function is being used also to optimize
5116 A op B ? C : A, by reversing the comparison first.
5118 Return a folded expression whose code is not a COND_EXPR
5119 anymore, or NULL_TREE if no folding opportunity is found. */
5121 static tree
5124 {
5129 tree tem;
5134 /* If we have A op 0 ? A : -A, consider applying the following
5135 transformations:
5137 A == 0? A : -A same as -A
5138 A != 0? A : -A same as A
5139 A >= 0? A : -A same as abs (A)
5140 A > 0? A : -A same as abs (A)
5141 A <= 0? A : -A same as -abs (A)
5142 A < 0? A : -A same as -abs (A)
5144 None of these transformations work for modes with signed
5145 zeros. If A is +/-0, the first two transformations will
5146 change the sign of the result (from +0 to -0, or vice
5147 versa). The last four will fix the sign of the result,
5148 even though the original expressions could be positive or
5149 negative, depending on the sign of A.
5151 Note that all these transformations are correct if A is
5152 NaN, since the two alternatives (A and -A) are also NaNs. */
5159 /* In the case that A is of the form X-Y, '-A' (arg2) may
5160 have already been folded to Y-X, check for that. */
5168 {
5180 /* Fall through. */
5191 /* FALLTHRU */
5201 }
5203 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5204 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5205 both transformations are correct when A is NaN: A != 0
5206 is then true, and A == 0 is false. */
5210 {
5215 }
5217 /* Try some transformations of A op B ? A : B.
5219 A == B? A : B same as B
5220 A != B? A : B same as A
5221 A >= B? A : B same as max (A, B)
5222 A > B? A : B same as max (B, A)
5223 A <= B? A : B same as min (A, B)
5224 A < B? A : B same as min (B, A)
5226 As above, these transformations don't work in the presence
5227 of signed zeros. For example, if A and B are zeros of
5228 opposite sign, the first two transformations will change
5229 the sign of the result. In the last four, the original
5230 expressions give different results for (A=+0, B=-0) and
5231 (A=-0, B=+0), but the transformed expressions do not.
5233 The first two transformations are correct if either A or B
5234 is a NaN. In the first transformation, the condition will
5235 be false, and B will indeed be chosen. In the case of the
5236 second transformation, the condition A != B will be true,
5237 and A will be chosen.
5239 The conversions to max() and min() are not correct if B is
5240 a number and A is not. The conditions in the original
5241 expressions will be false, so all four give B. The min()
5242 and max() versions would give a NaN instead. */
5245 /* Avoid these transformations if the COND_EXPR may be used
5246 as an lvalue in the C++ front-end. PR c++/19199. */
5247 && (in_gimple_form
5253 {
5259 {
5268 /* In C++ a ?: expression can be an lvalue, so put the
5269 operand which will be used if they are equal first
5270 so that we can convert this back to the
5271 corresponding COND_EXPR. */
5273 {
5281 }
5288 {
5296 }
5309 }
5310 }
5313 }
5316 \f
5317 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5318 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5319 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5320 false) >= 2)
5321 #endif
5323 /* EXP is some logical combination of boolean tests. See if we can
5324 merge it into some range test. Return the new tree if so. */
5326 static tree
5329 {
5345 /* If this is an OR operation, invert both sides; we will invert
5346 again at the end. */
5350 /* If both expressions are the same, if we can merge the ranges, and we
5351 can build the range test, return it or it inverted. If one of the
5352 ranges is always true or always false, consider it to be the same
5353 expression as the other. */
5361 {
5365 }
5367 /* On machines where the branch cost is expensive, if this is a
5368 short-circuited branch and the underlying object on both sides
5369 is the same, make a non-short-circuit operation. */
5371 && !flag_sanitize_coverage
5376 {
5377 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5378 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5379 which cases we can't do this. */
5387 {
5396 {
5399 WARN_STRICT_OVERFLOW_COMPARISON);
5403 }
5404 }
5405 }
5408 }
5409 \f
5410 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5411 bit value. Arrange things so the extra bits will be set to zero if and
5412 only if C is signed-extended to its full width. If MASK is nonzero,
5413 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5415 static tree
5417 {
5420 tree temp;
5425 /* We work by getting just the sign bit into the low-order bit, then
5426 into the high-order bit, then sign-extend. We then XOR that value
5427 with C. */
5431 /* We must use a signed type in order to get an arithmetic right shift.
5432 However, we must also avoid introducing accidental overflows, so that
5433 a subsequent call to integer_zerop will work. Hence we must
5434 do the type conversion here. At this point, the constant is either
5435 zero or one, and the conversion to a signed type can never overflow.
5436 We could get an overflow if this conversion is done anywhere else. */
5445 /* If necessary, convert the type back to match the type of C. */
5450 }
5451 \f
5452 /* For an expression that has the form
5453 (A && B) || ~B
5454 or
5455 (A || B) && ~B,
5456 we can drop one of the inner expressions and simplify to
5457 A || ~B
5458 or
5459 A && ~B
5460 LOC is the location of the resulting expression. OP is the inner
5461 logical operation; the left-hand side in the examples above, while CMPOP
5462 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5463 removing a condition that guards another, as in
5464 (A != NULL && A->...) || A == NULL
5465 which we must not transform. If RHS_ONLY is true, only eliminate the
5466 right-most operand of the inner logical operation. */
5468 static tree
5471 {
5489 {
5492 {
5495 }
5496 }
5498 {
5501 {
5504 }
5505 }
5520 }
5522 /* Find ways of folding logical expressions of LHS and RHS:
5523 Try to merge two comparisons to the same innermost item.
5524 Look for range tests like "ch >= '0' && ch <= '9'".
5525 Look for combinations of simple terms on machines with expensive branches
5526 and evaluate the RHS unconditionally.
5528 For example, if we have p->a == 2 && p->b == 4 and we can make an
5529 object large enough to span both A and B, we can do this with a comparison
5530 against the object ANDed with the a mask.
5532 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5533 operations to do this with one comparison.
5535 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5536 function and the one above.
5538 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5539 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5541 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5542 two operands.
5544 We return the simplified tree or 0 if no optimization is possible. */
5546 static tree
5549 {
5550 /* If this is the "or" of two comparisons, we can do something if
5551 the comparisons are NE_EXPR. If this is the "and", we can do something
5552 if the comparisons are EQ_EXPR. I.e.,
5553 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5555 WANTED_CODE is this operation code. For single bit fields, we can
5556 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5557 comparison for one-bit fields. */
5578 /* Start by getting the comparison codes. Fail if anything is volatile.
5579 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5580 it were surrounded with a NE_EXPR. */
5589 {
5593 }
5596 {
5600 }
5611 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5614 {
5617 {
5622 }
5625 {
5631 }
5632 }
5637 /* If the RHS can be evaluated unconditionally and its operands are
5638 simple, it wins to evaluate the RHS unconditionally on machines
5639 with expensive branches. In this case, this isn't a comparison
5640 that can be merged. */
5647 {
5648 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5659 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5669 }
5671 /* See if the comparisons can be merged. Then get all the parameters for
5672 each side. */
5697 /* It must be true that the inner operation on the lhs of each
5698 comparison must be the same if we are to be able to do anything.
5699 Then see if we have constants. If not, the same must be true for
5700 the rhs's. */
5709 {
5712 }
5717 else
5720 /* If either comparison code is not correct for our logical operation,
5721 fail. However, we can convert a one-bit comparison against zero into
5722 the opposite comparison against that bit being set in the field. */
5726 {
5728 {
5729 /* Make the left operand unsigned, since we are only interested
5730 in the value of one bit. Otherwise we are doing the wrong
5731 thing below. */
5734 }
5735 else
5737 }
5739 /* This is analogous to the code for l_const above. */
5741 {
5743 {
5746 }
5747 else
5749 }
5751 /* See if we can find a mode that contains both fields being compared on
5752 the left. If we can't, fail. Otherwise, update all constants and masks
5753 to be relative to a field of that size. */
5767 {
5770 }
5778 {
5785 {
5789 }
5790 }
5792 {
5799 {
5803 }
5804 }
5806 /* If the right sides are not constant, do the same for it. Also,
5807 disallow this optimization if a size or signedness mismatch occurs
5808 between the left and right sides. */
5810 {
5813 /* Make sure the two fields on the right
5814 correspond to the left without being swapped. */
5831 {
5834 }
5843 /* Make a mask that corresponds to both fields being compared.
5844 Do this for both items being compared. If the operands are the
5845 same size and the bits being compared are in the same position
5846 then we can do this by masking both and comparing the masked
5847 results. */
5854 {
5868 }
5870 /* There is still another way we can do something: If both pairs of
5871 fields being compared are adjacent, we may be able to make a wider
5872 field containing them both.
5874 Note that we still must mask the lhs/rhs expressions. Furthermore,
5875 the mask must be shifted to account for the shift done by
5876 make_bit_field_ref. */
5885 {
5886 tree type;
5902 /* Convert to the smaller type before masking out unwanted bits. */
5905 {
5907 {
5911 }
5913 {
5917 }
5918 }
5927 }
5930 }
5932 /* Handle the case of comparisons with constants. If there is something in
5933 common between the masks, those bits of the constants must be the same.
5934 If not, the condition is always false. Test for this to avoid generating
5935 incorrect code below. */
5940 {
5942 {
5945 }
5946 else
5947 {
5950 }
5951 }
5956 /* Construct the expression we will return. First get the component
5957 reference we will make. Unless the mask is all ones the width of
5958 that field, perform the mask operation. Then compare with the
5959 merged constant. */
5970 }
5971 \f
5972 /* T is an integer expression that is being multiplied, divided, or taken a
5973 modulus (CODE says which and what kind of divide or modulus) by a
5974 constant C. See if we can eliminate that operation by folding it with
5975 other operations already in T. WIDE_TYPE, if non-null, is a type that
5976 should be used for the computation if wider than our type.
5978 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5979 (X * 2) + (Y * 4). We must, however, be assured that either the original
5980 expression would not overflow or that overflow is undefined for the type
5981 in the language in question.
5983 If we return a non-null expression, it is an equivalent form of the
5984 original computation, but need not be in the original type.
5986 We set *STRICT_OVERFLOW_P to true if the return values depends on
5987 signed overflow being undefined. Otherwise we do not change
5988 *STRICT_OVERFLOW_P. */
5990 static tree
5993 {
5994 /* To avoid exponential search depth, refuse to allow recursion past
5995 three levels. Beyond that (1) it's highly unlikely that we'll find
5996 something interesting and (2) we've probably processed it before
5997 when we built the inner expression. */
6000 tree ret;
6005 depth++;
6007 depth--;
6010 }
6012 static tree
6015 {
6027 /* Don't deal with constants of zero here; they confuse the code below. */
6037 /* Note that we need not handle conditional operations here since fold
6038 already handles those cases. So just do arithmetic here. */
6040 {
6042 /* For a constant, we can always simplify if we are a multiply
6043 or (for divide and modulus) if it is a multiple of our constant. */
6047 {
6050 /* If the multiplication overflowed, we lost information on it.
6051 See PR68142 and PR69845. */
6055 }
6059 /* If op0 is an expression ... */
6065 /* ... and has wrapping overflow, and its type is smaller
6066 than ctype, then we cannot pass through as widening. */
6071 /* ... or this is a truncation (t is narrower than op0),
6072 then we cannot pass through this narrowing. */
6075 /* ... or signedness changes for division or modulus,
6076 then we cannot pass through this conversion. */
6080 /* ... or has undefined overflow while the converted to
6081 type has not, we cannot do the operation in the inner type
6082 as that would introduce undefined overflow. */
6088 /* Pass the constant down and see if we can make a simplification. If
6089 we can, replace this expression with the inner simplification for
6090 possible later conversion to our or some other type. */
6095 code == MULT_EXPR
6097 strict_overflow_p))))
6102 /* If widening the type changes it from signed to unsigned, then we
6103 must avoid building ABS_EXPR itself as unsigned. */
6105 {
6109 {
6112 }
6114 }
6115 /* If the constant is negative, we cannot simplify this. */
6118 /* FALLTHROUGH */
6120 /* For division and modulus, type can't be unsigned, as e.g.
6121 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6122 For signed types, even with wrapping overflow, this is fine. */
6131 /* If widening the type changes the signedness, then we can't perform
6132 this optimization as that changes the result. */
6136 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6142 {
6149 }
6153 /* If the second operand is constant, this is a multiplication
6154 or floor division, by a power of two, so we can treat it that
6155 way unless the multiplier or divisor overflows. Signed
6156 left-shift overflow is implementation-defined rather than
6157 undefined in C90, so do not convert signed left shift into
6158 multiplication. */
6161 /* const_binop may not detect overflow correctly,
6162 so check for it explicitly here. */
6167 size_one_node,
6168 op1)))
6172 ctype,
6174 t1),
6179 /* See if we can eliminate the operation on both sides. If we can, we
6180 can return a new PLUS or MINUS. If we can't, the only remaining
6181 cases where we can do anything are if the second operand is a
6182 constant. */
6189 /* If not multiplication, we can only do this if both operands
6190 are divisible by c. */
6193 {
6198 }
6200 /* If this was a subtraction, negate OP1 and set it to be an addition.
6201 This simplifies the logic below. */
6203 {
6205 /* If OP1 was not easily negatable, the constant may be OP0. */
6207 {
6210 }
6211 }
6216 /* If either OP1 or C are negative, this optimization is not safe for
6217 some of the division and remainder types while for others we need
6218 to change the code. */
6220 {
6228 }
6230 /* If it's a multiply or a division/modulus operation of a multiple
6231 of our constant, do the operation and verify it doesn't overflow. */
6235 {
6238 /* We allow the constant to overflow with wrapping semantics. */
6242 }
6243 else
6246 /* If we have an unsigned type, we cannot widen the operation since it
6247 will change the result if the original computation overflowed. */
6251 /* The last case is if we are a multiply. In that case, we can
6252 apply the distributive law to commute the multiply and addition
6253 if the multiplication of the constants doesn't overflow
6254 and overflow is defined. With undefined overflow
6255 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6261 op1);
6266 /* We have a special case here if we are doing something like
6267 (C * 8) % 4 since we know that's zero. */
6270 /* If the multiplication can overflow we cannot optimize this. */
6275 {
6278 }
6280 /* ... fall through ... */
6284 /* If we can extract our operation from the LHS, do so and return a
6285 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6286 do something only if the second operand is a constant. */
6302 /* If these are the same operation types, we can associate them
6303 assuming no overflow. */
6305 {
6320 }
6322 /* If these operations "cancel" each other, we have the main
6323 optimizations of this pass, which occur when either constant is a
6324 multiple of the other, in which case we replace this with either an
6325 operation or CODE or TCODE.
6327 If we have an unsigned type, we cannot do this since it will change
6328 the result if the original computation overflowed. */
6335 {
6338 {
6345 }
6348 {
6355 }
6356 }
6361 }
6364 }
6365 \f
6366 /* Return a node which has the indicated constant VALUE (either 0 or
6367 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6368 and is of the indicated TYPE. */
6370 tree
6372 {
6381 else
6383 }
6386 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6387 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6388 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6389 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6390 COND is the first argument to CODE; otherwise (as in the example
6391 given here), it is the second argument. TYPE is the type of the
6392 original expression. Return NULL_TREE if no simplification is
6393 possible. */
6395 static tree
6400 {
6410 {
6414 /* If this operand throws an expression, then it does not make
6415 sense to try to perform a logical or arithmetic operation
6416 involving it. */
6421 }
6424 {
6429 }
6430 else
6431 /* Detect the case of mixing vector and scalar types - bail out. */
6437 /* This transformation is only worthwhile if we don't have to wrap ARG
6438 in a SAVE_EXPR and the operation can be simplified without recursing
6439 on at least one of the branches once its pushed inside the COND_EXPR. */
6448 {
6452 else
6454 }
6456 {
6460 else
6462 }
6464 /* Check that we have simplified at least one of the branches. */
6469 }
6471 \f
6472 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6474 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6475 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6476 ADDEND is the same as X.
6478 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6479 and finite. The problematic cases are when X is zero, and its mode
6480 has signed zeros. In the case of rounding towards -infinity,
6481 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6482 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6484 bool
6486 {
6490 /* Don't allow the fold with -fsignaling-nans. */
6494 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6498 /* In a vector or complex, we would need to check the sign of all zeros. */
6502 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6506 /* The mode has signed zeros, and we have to honor their sign.
6507 In this situation, there is only one case we can return true for.
6508 X - 0 is the same as X unless rounding towards -infinity is
6509 supported. */
6511 }
6513 /* Subroutine of match.pd that optimizes comparisons of a division by
6514 a nonzero integer constant against an integer constant, i.e.
6515 X/C1 op C2.
6517 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6518 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6520 enum tree_code
6523 {
6528 /* We have to do this the hard way to detect unsigned overflow.
6529 prod = int_const_binop (MULT_EXPR, c1, c2); */
6535 {
6539 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6542 }
6544 {
6547 {
6566 }
6567 }
6568 else
6569 {
6570 /* A negative divisor reverses the relational operators. */
6575 {
6594 }
6595 }
6608 }
6611 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6612 equality/inequality test, then return a simplified form of the test
6613 using a sign testing. Otherwise return NULL. TYPE is the desired
6614 result type. */
6616 static tree
6619 tree result_type)
6620 {
6621 /* If this is testing a single bit, we can optimize the test. */
6625 {
6626 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6627 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6631 /* This is only a win if casting to a signed type is cheap,
6632 i.e. when arg00's type is not a partial mode. */
6634 {
6637 result_type,
6640 }
6641 }
6644 }
6646 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6647 equality/inequality test, then return a simplified form of
6648 the test using shifts and logical operations. Otherwise return
6649 NULL. TYPE is the desired result type. */
6651 tree
6654 {
6655 /* If this is testing a single bit, we can optimize the test. */
6659 {
6668 /* First, see if we can fold the single bit test into a sign-bit
6669 test. */
6671 result_type);
6675 /* Otherwise we have (A & C) != 0 where C is a single bit,
6676 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6677 Similarly for (A & C) == 0. */
6679 /* If INNER is a right shift of a constant and it plus BITNUM does
6680 not overflow, adjust BITNUM and INNER. */
6686 {
6689 }
6691 /* If we are going to be able to omit the AND below, we must do our
6692 operations as unsigned. If we must use the AND, we have a choice.
6693 Normally unsigned is faster, but for some machines signed is. */
6711 /* Put the AND last so it can combine with more things. */
6714 /* Make sure to return the proper type. */
6718 }
6720 }
6722 /* Test whether it is preferable two swap two operands, ARG0 and
6723 ARG1, for example because ARG0 is an integer constant and ARG1
6724 isn't. */
6726 bool
6728 {
6742 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6743 for commutative and comparison operators. Ensuring a canonical
6744 form allows the optimizers to find additional redundancies without
6745 having to explicitly check for both orderings. */
6751 /* Put SSA_NAMEs last. */
6757 /* Put variables last. */
6764 }
6767 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6768 means A >= Y && A != MAX, but in this case we know that
6769 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6771 static tree
6773 {
6780 else
6789 {
6792 }
6794 {
6797 }
6798 else
6805 {
6806 /* Convert the pointer types into integer before taking the difference. */
6810 }
6811 else
6818 }
6820 /* Fold a sum or difference of at least one multiplication.
6821 Returns the folded tree or NULL if no simplification could be made. */
6823 static tree
6826 {
6830 /* (A * C) +- (B * C) -> (A+-B) * C.
6831 (A * C) +- A -> A * (C+-1).
6832 We are most concerned about the case where C is a constant,
6833 but other combinations show up during loop reduction. Since
6834 it is not difficult, try all four possibilities. */
6837 {
6840 }
6842 {
6845 }
6846 else
6847 {
6848 /* We cannot generate constant 1 for fract. */
6853 }
6855 {
6858 }
6860 {
6862 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6863 the purpose of this canonicalization. */
6867 {
6870 }
6871 else
6873 }
6874 else
6875 {
6876 /* We cannot generate constant 1 for fract. */
6881 }
6884 /* Prefer factoring a common non-constant. */
6894 /* No identical multiplicands; see if we can find a common
6895 power-of-two factor in non-power-of-two multiplies. This
6896 can help in multi-dimensional array access. */
6899 {
6902 tree maybe_same;
6906 /* Move min of absolute values to int11. */
6908 {
6913 }
6914 else
6918 /* The remainder should not be a constant, otherwise we
6919 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6920 increased the number of multiplications necessary. */
6922 {
6930 }
6931 }
6938 /* We are neither factoring zero nor minus one. */
6946 /* Same may be zero and thus the operation 'code' may overflow. Likewise
6947 same may be minus one and thus the multiplication may overflow. Perform
6948 the operations in an unsigned type. */
6953 /* If the sum evaluated to a constant that is not -INF the multiplication
6954 cannot overflow. */
6964 }
6966 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6967 specified by EXPR into the buffer PTR of length LEN bytes.
6968 Return the number of bytes placed in the buffer, or zero
6969 upon failure. */
6971 static int
6973 {
6985 /* Dry run. */
6991 {
6993 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
6994 number of bytes. */
6998 {
7005 else
7007 }
7008 else
7012 }
7014 }
7017 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7018 specified by EXPR into the buffer PTR of length LEN bytes.
7019 Return the number of bytes placed in the buffer, or zero
7020 upon failure. */
7022 static int
7024 {
7028 FIXED_VALUE_TYPE value;
7043 }
7046 /* Subroutine of native_encode_expr. Encode the REAL_CST
7047 specified by EXPR into the buffer PTR of length LEN bytes.
7048 Return the number of bytes placed in the buffer, or zero
7049 upon failure. */
7051 static int
7053 {
7059 /* There are always 32 bits in each long, no matter the size of
7060 the hosts long. We handle floating point representations with
7061 up to 192 bits. */
7070 /* Dry run. */
7079 {
7084 {
7091 else
7093 }
7094 else
7095 {
7098 {
7099 /* Reverse bytes within each long, or within the entire float
7100 if it's smaller than a long (for HFmode). */
7103 }
7104 }
7109 }
7111 }
7113 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7114 specified by EXPR into the buffer PTR of length LEN bytes.
7115 Return the number of bytes placed in the buffer, or zero
7116 upon failure. */
7118 static int
7120 {
7122 tree part;
7136 }
7139 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7140 specified by EXPR into the buffer PTR of length LEN bytes.
7141 Return the number of bytes placed in the buffer, or zero
7142 upon failure. */
7144 static int
7146 {
7156 {
7158 {
7161 }
7172 }
7174 }
7177 /* Subroutine of native_encode_expr. Encode the STRING_CST
7178 specified by EXPR into the buffer PTR of length LEN bytes.
7179 Return the number of bytes placed in the buffer, or zero
7180 upon failure. */
7182 static int
7184 {
7187 /* Wide-char strings are encoded in target byte-order so native
7188 encoding them is trivial. */
7203 {
7206 {
7209 }
7212 }
7213 else
7216 }
7219 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7220 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7221 buffer PTR of length LEN bytes. If PTR is NULL, don't actually store
7222 anything, just do a dry run. If OFF is not -1 then start
7223 the encoding at byte offset OFF and encode at most LEN bytes.
7224 Return the number of bytes placed in the buffer, or zero upon failure. */
7226 int
7228 {
7229 /* We don't support starting at negative offset and -1 is special. */
7234 {
7255 }
7256 }
7259 /* Subroutine of native_interpret_expr. Interpret the contents of
7260 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7261 If the buffer cannot be interpreted, return NULL_TREE. */
7263 static tree
7265 {
7275 }
7278 /* Subroutine of native_interpret_expr. Interpret the contents of
7279 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7280 If the buffer cannot be interpreted, return NULL_TREE. */
7282 static tree
7284 {
7287 double_int result;
7288 FIXED_VALUE_TYPE fixed_value;
7298 }
7301 /* Subroutine of native_interpret_expr. Interpret the contents of
7302 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7303 If the buffer cannot be interpreted, return NULL_TREE. */
7305 static tree
7307 {
7311 /* There are always 32 bits in each long, no matter the size of
7312 the hosts long. We handle floating point representations with
7313 up to 192 bits. */
7314 REAL_VALUE_TYPE r;
7324 {
7325 /* Both OFFSET and BYTE index within a long;
7326 bitpos indexes the whole float. */
7329 {
7336 else
7338 }
7339 else
7340 {
7343 {
7344 /* Reverse bytes within each long, or within the entire float
7345 if it's smaller than a long (for HFmode). */
7348 }
7349 }
7353 }
7357 }
7360 /* Subroutine of native_interpret_expr. Interpret the contents of
7361 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7362 If the buffer cannot be interpreted, return NULL_TREE. */
7364 static tree
7366 {
7381 }
7384 /* Subroutine of native_interpret_expr. Interpret the contents of
7385 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7386 If the buffer cannot be interpreted, return NULL_TREE. */
7388 static tree
7390 {
7402 {
7407 }
7409 }
7412 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7413 the buffer PTR of length LEN as a constant of type TYPE. For
7414 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7415 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7416 return NULL_TREE. */
7418 tree
7420 {
7422 {
7444 }
7445 }
7447 /* Returns true if we can interpret the contents of a native encoding
7448 as TYPE. */
7450 static bool
7452 {
7454 {
7467 }
7468 }
7471 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7472 TYPE at compile-time. If we're unable to perform the conversion
7473 return NULL_TREE. */
7475 static tree
7477 {
7478 /* We support up to 512-bit values (for V8DFmode). */
7482 /* Check that the host and target are sane. */
7491 }
7493 /* Build an expression for the address of T. Folds away INDIRECT_REF
7494 to avoid confusing the gimplify process. */
7496 tree
7498 {
7499 /* The size of the object is not relevant when talking about its address. */
7504 {
7509 }
7519 {
7524 }
7525 else
7529 }
7531 /* Build an expression for the address of T. */
7533 tree
7535 {
7539 }
7541 /* Fold a unary expression of code CODE and type TYPE with operand
7542 OP0. Return the folded expression if folding is successful.
7543 Otherwise, return NULL_TREE. */
7545 tree
7547 {
7548 tree tem;
7549 tree arg0;
7557 {
7560 {
7561 /* Don't use STRIP_NOPS, because signedness of argument type
7562 matters. */
7564 }
7565 else
7566 {
7567 /* Strip any conversions that don't change the mode. This
7568 is safe for every expression, except for a comparison
7569 expression because its signedness is derived from its
7570 operands.
7572 Note that this is done as an internal manipulation within
7573 the constant folder, in order to find the simplest
7574 representation of the arguments so that their form can be
7575 studied. In any cases, the appropriate type conversions
7576 should be put back in the tree that will get out of the
7577 constant folder. */
7579 }
7582 {
7585 {
7589 }
7590 }
7591 }
7598 {
7605 {
7619 /* If this was a conversion, and all we did was to move into
7620 inside the COND_EXPR, bring it back out. But leave it if
7621 it is a conversion from integer to integer and the
7622 result precision is no wider than a word since such a
7623 conversion is cheap and may be optimized away by combine,
7624 while it couldn't if it were outside the COND_EXPR. Then return
7625 so we don't get into an infinite recursion loop taking the
7626 conversion out and then back in. */
7638 && (INTEGRAL_TYPE_P
7651 }
7652 }
7655 {
7661 CASE_CONVERT:
7665 {
7666 /* If we have (type) (a CMP b) and type is an integral type, return
7667 new expression involving the new type. Canonicalize
7668 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7669 non-integral type.
7670 Do not fold the result as that would not simplify further, also
7671 folding again results in recursions. */
7681 }
7683 /* Handle (T *)&A.B.C for A being of type T and B and C
7684 living at offset zero. This occurs frequently in
7685 C++ upcasting and then accessing the base. */
7689 {
7691 tree offset;
7692 machine_mode mode;
7694 tree base
7698 /* If the reference was to a (constant) zero offset, we can use
7699 the address of the base if it has the same base type
7700 as the result type and the pointer type is unqualified. */
7707 }
7711 /* Detect assigning a bitfield. */
7713 && DECL_BIT_FIELD
7715 {
7716 /* Don't leave an assignment inside a conversion
7717 unless assigning a bitfield. */
7719 /* First do the assignment, then return converted constant. */
7724 }
7726 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7727 constants (if x has signed type, the sign bit cannot be set
7728 in c). This folds extension into the BIT_AND_EXPR.
7729 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7730 very likely don't have maximal range for their precision and this
7731 transformation effectively doesn't preserve non-maximal ranges. */
7735 {
7746 <= HOST_BITS_PER_WIDE_INT
7748 {
7752 cst &= HOST_WIDE_INT_M1U
7756 && !flag_syntax_only
7759 {
7763 }
7764 }
7766 {
7771 }
7772 }
7774 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7775 cast (T1)X will fold away. We assume that this happens when X itself
7776 is a cast. */
7780 {
7784 return fold_build_pointer_plus_loc
7786 }
7788 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7789 of the same precision, and X is an integer type not narrower than
7790 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7796 {
7802 }
7804 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7805 type of X and Y (integer types only). */
7810 {
7811 /* Be careful not to introduce new overflows. */
7812 tree mult_type;
7815 else
7819 {
7826 }
7827 }
7833 {
7840 }
7851 /* Convert fabs((double)float) into (double)fabsf(float). */
7854 {
7860 targ0));
7861 }
7865 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7884 /* Note that the operand of this must be an int
7885 and its values must be 0 or 1.
7886 ("true" is a fixed value perhaps depending on the language,
7887 but we don't handle values other than 1 correctly yet.) */
7894 /* Fold *&X to X if X is an lvalue. */
7896 {
7903 }
7909 }
7912 /* If the operation was a conversion do _not_ mark a resulting constant
7913 with TREE_OVERFLOW if the original constant was not. These conversions
7914 have implementation defined behavior and retaining the TREE_OVERFLOW
7915 flag here would confuse later passes such as VRP. */
7916 tree
7919 {
7928 }
7930 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7931 operands OP0 and OP1. LOC is the location of the resulting expression.
7932 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7933 Return the folded expression if folding is successful. Otherwise,
7934 return NULL_TREE. */
7935 static tree
7938 {
7939 tree tem;
7941 /* We only do these simplifications if we are optimizing. */
7945 /* Check for things like (A || B) && (A || C). We can convert this
7946 to A || (B && C). Note that either operator can be any of the four
7947 truth and/or operations and the transformation will still be
7948 valid. Also note that we only care about order for the
7949 ANDIF and ORIF operators. If B contains side effects, this
7950 might change the truth-value of A. */
7957 {
7977 /* This case if tricky because we must either have commutative
7978 operators or else A10 must not have side-effects. */
7984 a01);
7985 }
7987 /* See if we can build a range comparison. */
7993 {
7997 }
8001 {
8005 }
8007 /* Check for the possibility of merging component references. If our
8008 lhs is another similar operation, try to merge its rhs with our
8009 rhs. Then try to merge our lhs and rhs. */
8019 && !flag_sanitize_coverage
8024 {
8031 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8032 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8033 We don't want to pack more than two leafs to a non-IF AND/OR
8034 expression.
8035 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8036 equal to IF-CODE, then we don't want to add right-hand operand.
8037 If the inner right-hand side of left-hand operand has
8038 side-effects, or isn't simple, then we can't add to it,
8039 as otherwise we might destroy if-sequence. */
8042 /* Needed for sequence points to handle trappings, and
8043 side-effects. */
8045 {
8047 arg1);
8049 tem);
8050 }
8051 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8052 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8055 /* Needed for sequence points to handle trappings, and
8056 side-effects. */
8058 {
8063 }
8064 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8065 into (A OR B).
8066 For sequence point consistancy, we need to check for trapping,
8067 and side-effects. */
8071 }
8074 }
8076 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8077 by changing CODE to reduce the magnitude of constants involved in
8078 ARG0 of the comparison.
8079 Returns a canonicalized comparison tree if a simplification was
8080 possible, otherwise returns NULL_TREE.
8081 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8082 valid if signed overflow is undefined. */
8084 static tree
8088 {
8093 /* Match A +- CST code arg1. We can change this only if overflow
8094 is undefined. */
8097 /* In principle pointers also have undefined overflow behavior,
8098 but that causes problems elsewhere. */
8105 /* Identify the constant in arg0 and its sign. */
8109 /* Overflowed constants and zero will cause problems. */
8114 /* See if we can reduce the magnitude of the constant in
8115 arg0 by changing the comparison code. */
8116 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8120 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8124 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8128 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8132 else
8136 /* Now build the constant reduced in magnitude. But not if that
8137 would produce one outside of its types range. */
8153 }
8155 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8156 overflow further. Try to decrease the magnitude of constants involved
8157 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8158 and put sole constants at the second argument position.
8159 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8161 static tree
8164 {
8165 tree t;
8170 /* Try canonicalization by simplifying arg0. */
8175 {
8179 }
8181 /* Try canonicalization by simplifying arg1 using the swapped
8182 comparison. */
8190 }
8192 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8193 space. This is used to avoid issuing overflow warnings for
8194 expressions like &p->x which can not wrap. */
8196 static bool
8198 {
8205 wide_int wi_offset;
8211 else
8227 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8228 array. */
8230 {
8231 HOST_WIDE_INT base_size;
8236 }
8239 }
8241 /* Return a positive integer when the symbol DECL is known to have
8242 a nonzero address, zero when it's known not to (e.g., it's a weak
8243 symbol), and a negative integer when the symbol is not yet in the
8244 symbol table and so whether or not its address is zero is unknown.
8245 For function local objects always return positive integer. */
8246 static int
8248 {
8253 /* Function local objects are never NULL. */
8261 }
8263 /* Subroutine of fold_binary. This routine performs all of the
8264 transformations that are common to the equality/inequality
8265 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8266 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8267 fold_binary should call fold_binary. Fold a comparison with
8268 tree code CODE and type TYPE with operands OP0 and OP1. Return
8269 the folded comparison or NULL_TREE. */
8271 static tree
8274 {
8284 /* For comparisons of pointers we can decompose it to a compile time
8285 comparison of the base objects and the offsets into the object.
8286 This requires at least one operand being an ADDR_EXPR or a
8287 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8293 {
8296 machine_mode mode;
8300 /* Get base and offset for the access. Strip ADDR_EXPR for
8301 get_inner_reference, but put it back by stripping INDIRECT_REF
8302 off the base object if possible. indirect_baseN will be true
8303 if baseN is not an address but refers to the object itself. */
8306 {
8307 base0
8313 else
8315 }
8317 {
8321 {
8322 base0
8328 else
8330 }
8333 else
8337 {
8343 {
8346 }
8347 }
8348 }
8352 {
8353 base1
8359 else
8361 }
8363 {
8367 {
8368 base1
8374 else
8376 }
8379 else
8383 {
8389 {
8392 }
8393 }
8394 }
8396 /* If we have equivalent bases we might be able to simplify. */
8400 {
8401 /* We can fold this expression to a constant if the non-constant
8402 offset parts are equal. */
8406 {
8412 "occur when comparing P +- C1 with "
8414 WARN_STRICT_OVERFLOW_CONDITIONAL);
8417 {
8431 }
8432 }
8433 /* We can simplify the comparison to a comparison of the variable
8434 offset parts if the constant offset parts are equal.
8435 Be careful to use signed sizetype here because otherwise we
8436 mess with array offsets in the wrong way. This is possible
8437 because pointer arithmetic is restricted to retain within an
8438 object and overflow on pointer differences is undefined as of
8439 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8441 {
8442 /* By converting to signed sizetype we cover middle-end pointer
8443 arithmetic which operates on unsigned pointer types of size
8444 type size and ARRAY_REF offsets which are properly sign or
8445 zero extended from their type in case it is narrower than
8446 sizetype. */
8449 else
8453 else
8460 "occur when comparing P +- C1 with "
8462 WARN_STRICT_OVERFLOW_COMPARISON);
8465 }
8466 }
8467 /* For equal offsets we can simplify to a comparison of the
8468 base addresses. */
8470 && (indirect_base0
8472 && (indirect_base1
8477 {
8483 }
8484 /* Comparison between an ordinary (non-weak) symbol and a null
8485 pointer can be eliminated since such symbols must have a non
8486 null address. In C, relational expressions between pointers
8487 to objects and null pointers are undefined. The results
8488 below follow the C++ rules with the additional property that
8489 every object pointer compares greater than a null pointer.
8490 */
8493 /* Avoid folding references to struct members at offset 0 to
8494 prevent tests like '&ptr->firstmember == 0' from getting
8495 eliminated. When ptr is null, although the -> expression
8496 is strictly speaking invalid, GCC retains it as a matter
8497 of QoI. See PR c/44555. */
8500 && indirect_base0
8501 /* The caller guarantees that when one of the arguments is
8502 constant (i.e., null in this case) it is second. */
8504 {
8506 {
8517 }
8518 }
8519 }
8521 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8522 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8523 the resulting offset is smaller in absolute value than the
8524 original one and has the same sign. */
8533 {
8538 tree cst;
8540 "occur when combining constants around "
8543 /* Put the constant on the side where it doesn't overflow and is
8544 of lower absolute value and of same sign than before. */
8551 {
8554 variable1,
8558 }
8566 {
8572 variable2);
8573 }
8574 }
8580 /* If we are comparing an expression that just has comparisons
8581 of two integer values, arithmetic expressions of those comparisons,
8582 and constants, we can simplify it. There are only three cases
8583 to check: the two values can either be equal, the first can be
8584 greater, or the second can be greater. Fold the expression for
8585 those three values. Since each value must be 0 or 1, we have
8586 eight possibilities, each of which corresponds to the constant 0
8587 or 1 or one of the six possible comparisons.
8589 This handles common cases like (a > b) == 0 but also handles
8590 expressions like ((x > y) - (y > x)) > 0, which supposedly
8591 occur in macroized code. */
8594 {
8599 /* Don't handle degenerate cases here; they should already
8600 have been handled anyway. */
8609 {
8613 /* We can't just pass T to eval_subst in case cval1 or cval2
8614 was the same as ARG1. */
8616 tree high_result
8620 arg1);
8621 tree equal_result
8625 arg1);
8626 tree low_result
8630 arg1);
8632 /* All three of these results should be 0 or 1. Confirm they are.
8633 Then use those values to select the proper code to use. */
8638 {
8639 /* Make a 3-bit mask with the high-order bit being the
8640 value for `>', the next for '=', and the low for '<'. */
8644 {
8646 /* Always false. */
8667 /* Always true. */
8669 }
8672 {
8676 }
8678 }
8679 }
8680 }
8683 }
8686 /* Subroutine of fold_binary. Optimize complex multiplications of the
8687 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8688 argument EXPR represents the expression "z" of type TYPE. */
8690 static tree
8692 {
8697 {
8700 }
8702 {
8705 }
8706 else
8707 {
8711 }
8720 }
8723 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8724 CONSTRUCTOR ARG into array ELTS, which has NELTS elements, and return
8725 true if successful. */
8727 static bool
8729 {
8733 {
8736 }
8738 {
8744 else
8746 }
8747 else
8753 }
8755 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8756 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8757 NULL_TREE otherwise. */
8759 static tree
8761 {
8780 {
8784 }
8787 {
8793 }
8794 else
8796 }
8798 /* Try to fold a pointer difference of type TYPE two address expressions of
8799 array references AREF0 and AREF1 using location LOC. Return a
8800 simplified expression for the difference or NULL_TREE. */
8802 static tree
8805 {
8810 /* If the bases are array references as well, recurse. If the bases
8811 are pointer indirections compute the difference of the pointers.
8812 If the bases are equal, we are set. */
8815 && (base_offset
8819 && (base_offset
8825 {
8831 base_offset,
8834 }
8836 }
8838 /* If the real or vector real constant CST of type TYPE has an exact
8839 inverse, return it, else return NULL. */
8841 tree
8843 {
8844 REAL_VALUE_TYPE r;
8845 tree unit_type;
8846 machine_mode mode;
8850 {
8860 {
8867 {
8872 }
8875 }
8879 }
8880 }
8882 /* Mask out the tz least significant bits of X of type TYPE where
8883 tz is the number of trailing zeroes in Y. */
8884 static wide_int
8886 {
8891 }
8893 /* Return true when T is an address and is known to be nonzero.
8894 For floating point we further ensure that T is not denormal.
8895 Similar logic is present in nonzero_address in rtlanal.h.
8897 If the return value is based on the assumption that signed overflow
8898 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8899 change *STRICT_OVERFLOW_P. */
8901 static bool
8903 {
8907 /* Doing something useful for floating point would need more work. */
8913 {
8916 strict_overflow_p);
8922 strict_overflow_p);
8930 }
8933 {
8936 strict_overflow_p);
8944 strict_overflow_p);
8959 strict_overflow_p);
8963 strict_overflow_p);
8966 {
8978 }
8982 }
8984 }
8986 /* Return true when T is an address and is known to be nonzero.
8987 Handle warnings about undefined signed overflow. */
8989 bool
8991 {
8998 "determining that expression is always "
9000 WARN_STRICT_OVERFLOW_MISC);
9002 }
9004 /* Return true if T is known not to be equal to an integer W. */
9006 bool
9008 {
9010 value_range_type rtype;
9012 {
9021 {
9026 }
9031 /* If T has some known zero bits and W has any of those bits set,
9032 then T is known not to be equal to W. */
9040 }
9041 }
9043 /* Fold a binary expression of code CODE and type TYPE with operands
9044 OP0 and OP1. LOC is the location of the resulting expression.
9045 Return the folded expression if folding is successful. Otherwise,
9046 return NULL_TREE. */
9048 tree
9051 {
9066 /* Strip any conversions that don't change the mode. This is
9067 safe for every expression, except for a comparison expression
9068 because its signedness is derived from its operands. So, in
9069 the latter case, only strip conversions that don't change the
9070 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9071 preserved.
9073 Note that this is done as an internal manipulation within the
9074 constant folder, in order to find the simplest representation
9075 of the arguments so that their form can be studied. In any
9076 cases, the appropriate type conversions should be put back in
9077 the tree that will get out of the constant folder. */
9080 {
9083 }
9084 else
9085 {
9088 }
9090 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9091 constant but we can't do arithmetic on them. */
9093 {
9096 {
9100 }
9101 }
9103 /* If this is a commutative operation, and ARG0 is a constant, move it
9104 to ARG1 to reduce the number of tests below. */
9109 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9110 to ARG1 to reduce the number of tests below. */
9119 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9121 First check for cases where an arithmetic operation is applied to a
9122 compound, conditional, or comparison operation. Push the arithmetic
9123 operation inside the compound or conditional to see if any folding
9124 can then be done. Convert comparison to conditional for this purpose.
9125 The also optimizes non-constant cases that used to be done in
9126 expand_expr.
9128 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9129 one of the operands is a comparison and the other is a comparison, a
9130 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9131 code below would make the expression more complex. Change it to a
9132 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9133 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9146 {
9150 boolean_type_node,
9158 }
9162 {
9164 {
9169 tem);
9170 }
9172 {
9177 tem);
9178 }
9183 {
9189 }
9194 {
9200 }
9201 }
9204 {
9206 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9209 {
9215 }
9217 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9220 {
9221 tree base;
9222 HOST_WIDE_INT coffset;
9231 }
9236 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9242 arg1),
9244 arg0)));
9250 {
9251 /* X + (X / CST) * -CST is X % CST. */
9256 {
9265 cst0));
9266 }
9267 }
9269 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9270 one. Make sure the type is not saturating and has the signedness of
9271 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9272 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9279 {
9283 }
9286 {
9287 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9288 (plus (plus (mult) (mult)) (foo)) so that we can
9289 take advantage of the factoring cases below. */
9298 {
9304 else
9317 parg0),
9319 marg)),
9323 return
9329 parg1)));
9330 }
9331 }
9332 else
9333 {
9334 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9335 to __complex__ ( x, y ). This is not the same for SNaNs or
9336 if signed zeros are involved. */
9340 {
9347 {
9351 {
9357 }
9359 {
9365 }
9366 }
9367 }
9369 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9370 We associate floats only if the user has specified
9371 -fassociative-math. */
9375 {
9380 {
9381 tree tree0;
9384 }
9385 }
9386 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9387 We associate floats only if the user has specified
9388 -fassociative-math. */
9392 {
9397 {
9398 tree tree0;
9401 }
9402 }
9403 }
9405 bit_rotate:
9406 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9407 is a rotate of A by C1 bits. */
9408 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9409 is a rotate of A by B bits.
9410 Similarly for (A << B) | (A >> (-B & C3)) where C3 is Z-1,
9411 though in this case CODE must be | and not + or ^, otherwise
9412 it doesn't return A when B is 0. */
9413 {
9415 tree rtype;
9424 /* Only create rotates in complete modes. Other cases are not
9425 expanded properly. */
9428 {
9441 {
9446 }
9451 {
9454 code0 == LSHIFT_EXPR
9457 }
9459 {
9469 {
9473 orig_tree01);
9475 }
9476 }
9480 {
9491 {
9495 orig_tree01);
9497 }
9498 }
9499 }
9500 }
9502 associate:
9503 /* In most languages, can't associate operations on floats through
9504 parentheses. Rather than remember where the parentheses were, we
9505 don't associate floats at all, unless the user has specified
9506 -fassociative-math.
9507 And, we need to make sure type is not saturating. */
9511 {
9517 /* Split both trees into variables, constants, and literals. Then
9518 associate each group together, the constants with literals,
9519 then the result with variables. This increases the chances of
9520 literals being recombined later and of generating relocatable
9521 expressions for the sum of a constant and literal. */
9529 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9533 /* With undefined overflow prefer doing association in a type
9534 which wraps on overflow, if that is one of the operand types. */
9537 {
9545 }
9547 /* With undefined overflow we can only associate constants with one
9548 variable, and constants whose association doesn't overflow. */
9551 {
9553 {
9554 /* ??? If split_tree would handle NEGATE_EXPR we could
9555 simply reject these cases and the allowed cases would
9556 be the var0/minus_var1 ones. */
9562 {
9565 }
9572 {
9575 }
9581 /* The only case we can still associate with two variables
9582 is if they cancel out. */
9586 }
9592 }
9594 /* Only do something if we found more than two objects. Otherwise,
9595 nothing has changed and we risk infinite recursion. */
9603 {
9615 {
9619 }
9621 {
9625 }
9627 /* Preserve the MINUS_EXPR if the negative part of the literal is
9628 greater than the positive part. Otherwise, the multiplicative
9629 folding code (i.e extract_muldiv) may be fooled in case
9630 unsigned constants are subtracted, like in the following
9631 example: ((X*2 + 4) - 8U)/2. */
9633 {
9637 /* But avoid ending up with only negated parts. */
9639 {
9643 }
9644 else
9645 {
9649 }
9650 }
9652 /* Don't introduce overflows through reassociation. */
9657 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9664 /* Eliminate minus_con0. */
9666 {
9673 else
9676 }
9678 /* Eliminate minus_var0. */
9680 {
9684 else
9687 }
9689 return
9692 }
9693 }
9698 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9706 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9707 __complex__ ( x, -y ). This is not the same for SNaNs or if
9708 signed zeros are involved. */
9712 {
9719 {
9723 {
9725 arg1r ? arg1r
9730 }
9732 {
9736 arg1i ? arg1i
9739 }
9740 }
9741 }
9743 /* A - B -> A + (-B) if B is easily negatable. */
9747 /* Avoid this transformation if B is a positive REAL_CST. */
9755 /* Fold &a[i] - &a[j] to i-j. */
9760 {
9766 }
9768 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9769 one. Make sure the type is not saturating and has the signedness of
9770 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9771 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9778 {
9782 }
9788 {
9789 /* Transform x * -C into -x * C if x is easily negatable. */
9804 {
9807 "occur when simplifying "
9809 WARN_STRICT_OVERFLOW_MISC);
9811 }
9813 /* Optimize z * conj(z) for integer complex numbers. */
9820 }
9821 else
9822 {
9823 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9824 This is not the same for NaNs or if signed zeros are
9825 involved. */
9831 {
9834 return
9840 return
9845 }
9847 /* Optimize z * conj(z) for floating point complex numbers.
9848 Guarded by flag_unsafe_math_optimizations as non-finite
9849 imaginary components don't produce scalar results. */
9858 }
9862 /* Canonicalize (X & C1) | C2. */
9866 {
9871 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9879 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9881 {
9884 }
9886 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9887 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9888 mode which allows further optimizations. */
9893 {
9898 {
9901 }
9902 }
9905 {
9910 }
9911 }
9913 /* See if this can be simplified into a rotate first. If that
9914 is unsuccessful continue in the association code. */
9918 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9926 /* See if this can be simplified into a rotate first. If that
9927 is unsuccessful continue in the association code. */
9931 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9936 {
9937 tree tem2;
9944 }
9945 /* Fold ~X & 1 as (X & 1) == 0. */
9949 {
9950 tree tem2;
9957 }
9958 /* Fold !X & 1 as X == 0. */
9961 {
9965 }
9967 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
9968 multiple of 1 << CST. */
9970 {
9977 }
9979 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
9980 bits from CST2. */
9984 {
9986 wide_int masked
9993 {
9994 /* Avoid the transform if arg1 is a mask of some
9995 mode which allows further optimizations. */
10002 }
10003 }
10005 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10006 ((A & N) + B) & M -> (A + B) & M
10007 Similarly if (N & M) == 0,
10008 ((A | N) + B) & M -> (A + B) & M
10009 and for - instead of + (or unary - instead of +)
10010 and/or ^ instead of |.
10011 If B is constant and (B & M) == 0, fold into A & M. */
10013 {
10022 {
10025 wide_int cst0;
10027 /* Now we know that arg0 is (C + D) or (C - D) or
10028 -C and arg1 (M) is == (1LL << cst) - 1.
10029 Store C into PMOP[0] and D into PMOP[1]. */
10033 {
10036 }
10043 {
10052 {
10055 }
10058 /* If C or D is of the form (A & N) where
10059 (N & M) == M, or of the form (A | N) or
10060 (A ^ N) where (N & M) == 0, replace it with A. */
10064 /* If C or D is a N where (N & M) == 0, it can be
10065 omitted (assumed 0). */
10073 }
10075 /* Only build anything new if we optimized one or both arguments
10076 above. */
10080 {
10083 {
10084 /* Perform the operations in a type that has defined
10085 overflow behavior. */
10091 }
10096 {
10104 else
10106 }
10109 else
10112 /* TEM is now the new binary +, - or unary - replacement. */
10116 }
10117 }
10118 }
10120 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10123 {
10128 return
10130 }
10135 /* Don't touch a floating-point divide by zero unless the mode
10136 of the constant can represent infinity. */
10142 /* (-A) / (-B) -> A / B */
10154 /* Fall through */
10157 /* Simplify A / (B << N) where A and B are positive and B is
10158 a power of 2, to A >> (N + log2(B)). */
10163 {
10166 {
10174 WARN_STRICT_OVERFLOW_MISC);
10180 }
10181 }
10183 /* Fall through */
10191 /* Convert -A / -B to A / B when the type is signed and overflow is
10192 undefined. */
10196 {
10199 "when distributing negation across "
10201 WARN_STRICT_OVERFLOW_MISC);
10206 }
10210 {
10213 "when distributing negation across "
10215 WARN_STRICT_OVERFLOW_MISC);
10220 }
10222 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10223 operation, EXACT_DIV_EXPR.
10225 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10226 At one time others generated faster code, it's not clear if they do
10227 after the last round to changes to the DIV code in expmed.c. */
10238 {
10242 WARN_STRICT_OVERFLOW_MISC);
10244 }
10256 {
10260 WARN_STRICT_OVERFLOW_MISC);
10262 }
10270 /* Since negative shift count is not well-defined,
10271 don't try to compute it in the compiler. */
10277 /* If we have a rotate of a bit operation with the rotate count and
10278 the second operand of the bit operation both constant,
10279 permute the two operations. */
10285 {
10293 }
10295 /* Two consecutive rotates adding up to the some integer
10296 multiple of the precision of the type can be ignored. */
10312 /* Note that the operands of this must be ints
10313 and their values must be 0 or 1.
10314 ("true" is a fixed value perhaps depending on the language.) */
10315 /* If first arg is constant zero, return it. */
10318 /* FALLTHRU */
10320 /* If either arg is constant true, drop it. */
10324 /* Preserve sequence points. */
10327 /* If second arg is constant zero, result is zero, but first arg
10328 must be evaluated. */
10331 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10332 case will be handled here. */
10336 /* !X && X is always false. */
10340 /* X && !X is always false. */
10345 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10346 means A >= Y && A != MAX, but in this case we know that
10347 A < X <= MAX. */
10351 {
10359 }
10368 /* Note that the operands of this must be ints
10369 and their values must be 0 or true.
10370 ("true" is a fixed value perhaps depending on the language.) */
10371 /* If first arg is constant true, return it. */
10374 /* FALLTHRU */
10376 /* If either arg is constant zero, drop it. */
10380 /* Preserve sequence points. */
10383 /* If second arg is constant true, result is true, but we must
10384 evaluate first arg. */
10387 /* Likewise for first arg, but note this only occurs here for
10388 TRUTH_OR_EXPR. */
10392 /* !X || X is always true. */
10396 /* X || !X is always true. */
10401 /* (X && !Y) || (!X && Y) is X ^ Y */
10404 {
10421 }
10430 /* If the second arg is constant zero, drop it. */
10433 /* If the second arg is constant true, this is a logical inversion. */
10435 {
10438 }
10439 /* Identical arguments cancel to zero. */
10443 /* !X ^ X is always true. */
10448 /* X ^ !X is always true. */
10464 /* bool_var != 1 becomes !bool_var. */
10471 /* bool_var == 0 becomes !bool_var. */
10478 /* !exp != 0 becomes !exp */
10483 /* If this is an EQ or NE comparison with zero and ARG0 is
10484 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10485 two operations, but the latter can be done in one less insn
10486 on machines that have only two-operand insns or on which a
10487 constant cannot be the first operand. */
10490 {
10495 {
10502 arg1);
10503 }
10506 {
10513 arg1);
10514 }
10515 }
10517 /* If this is an NE or EQ comparison of zero against the result of a
10518 signed MOD operation whose second operand is a power of 2, make
10519 the MOD operation unsigned since it is simpler and equivalent. */
10527 {
10537 }
10539 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10540 C1 is a valid shift constant, and C2 is a power of two, i.e.
10541 a single bit. */
10545 == INTEGER_CST
10548 {
10553 /* Check for a valid shift count. */
10555 {
10559 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10560 can be rewritten as (X & (C2 << C1)) != 0. */
10562 {
10567 }
10568 /* Otherwise, for signed (arithmetic) shifts,
10569 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10570 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10574 /* Otherwise, of unsigned (logical) shifts,
10575 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10576 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10577 else
10581 arg000);
10582 }
10583 }
10585 /* If this is a comparison of a field, we may be able to simplify it. */
10588 /* Handle the constant case even without -O
10589 to make sure the warnings are given. */
10591 {
10595 }
10597 /* Optimize comparisons of strlen vs zero to a compare of the
10598 first character of the string vs zero. To wit,
10599 strlen(ptr) == 0 => *ptr == 0
10600 strlen(ptr) != 0 => *ptr != 0
10601 Other cases should reduce to one of these two (or a constant)
10602 due to the return value of strlen being unsigned. */
10605 {
10613 {
10618 }
10619 }
10621 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10622 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10626 {
10631 {
10633 {
10636 }
10639 }
10640 }
10642 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10643 (X & C) == 0 when C is a single bit. */
10648 {
10655 arg1));
10656 }
10658 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10659 constant C is a power of two, i.e. a single bit. */
10666 {
10670 }
10672 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10673 when is C is a power of two, i.e. a single bit. */
10680 {
10686 }
10690 {
10693 }
10695 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10698 {
10706 {
10712 }
10714 {
10720 }
10722 {
10728 }
10730 {
10736 }
10737 }
10741 {
10748 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10749 operand_equal_p guarantees no side-effects so we don't need
10750 to use omit_one_operand on Z. */
10754 arg10));
10758 arg11));
10762 arg10));
10766 arg11));
10768 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10771 {
10777 }
10778 }
10780 /* Attempt to simplify equality/inequality comparisons of complex
10781 values. Only lower the comparison if the result is known or
10782 can be simplified to a single scalar comparison. */
10787 {
10792 {
10795 }
10796 else
10797 {
10800 }
10803 {
10806 }
10807 else
10808 {
10811 }
10815 {
10817 {
10822 }
10823 else
10824 {
10829 }
10830 }
10834 {
10836 {
10841 }
10842 else
10843 {
10848 }
10849 }
10850 }
10862 /* Transform comparisons of the form X +- C CMP X. */
10867 {
10872 /* (X - c) > X becomes false. */
10878 /* Likewise (X + c) < X becomes false. */
10884 /* Convert (X - c) <= X to true. */
10891 /* Convert (X + c) >= X to true. */
10897 }
10899 /* If we are comparing an ABS_EXPR with a constant, we can
10900 convert all the cases into explicit comparisons, but they may
10901 well not be faster than doing the ABS and one comparison.
10902 But ABS (X) <= C is a range comparison, which becomes a subtraction
10903 and a comparison, and is probably faster. */
10917 /* Convert ABS_EXPR<x> >= 0 to true. */
10924 {
10927 "when simplifying comparison of "
10929 WARN_STRICT_OVERFLOW_CONDITIONAL);
10932 arg0);
10933 }
10935 /* Convert ABS_EXPR<x> < 0 to false. */
10940 {
10943 "when simplifying comparison of "
10945 WARN_STRICT_OVERFLOW_CONDITIONAL);
10948 arg0);
10949 }
10951 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
10952 and similarly for >= into !=. */
10962 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
10963 otherwise Y might be >= # of bits in X's type and thus e.g.
10964 (unsigned char) (1 << Y) for Y 15 might be 0.
10965 If the cast is widening, then 1 << Y should have unsigned type,
10966 otherwise if Y is number of bits in the signed shift type minus 1,
10967 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
10968 31 might be 0xffffffff80000000. */
10979 {
10985 }
10997 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
10998 {
11010 }
11015 /* When pedantic, a compound expression can be neither an lvalue
11016 nor an integer constant expression. */
11019 /* Don't let (0, 0) be null pointer constant. */
11025 /* An ASSERT_EXPR should never be passed to fold_binary. */
11031 }
11033 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11034 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11035 of GOTO_EXPR. */
11037 static tree
11039 {
11041 {
11048 /* fall through */
11052 }
11053 }
11055 /* Return whether the sub-tree ST contains a label which is accessible from
11056 outside the sub-tree. */
11058 static bool
11060 {
11061 return
11063 }
11065 /* Fold a ternary expression of code CODE and type TYPE with operands
11066 OP0, OP1, and OP2. Return the folded expression if folding is
11067 successful. Otherwise, return NULL_TREE. */
11069 tree
11072 {
11073 tree tem;
11080 /* If this is a commutative operation, and OP0 is a constant, move it
11081 to OP1 to reduce the number of tests below. */
11090 /* Strip any conversions that don't change the mode. This is safe
11091 for every expression, except for a comparison expression because
11092 its signedness is derived from its operands. So, in the latter
11093 case, only strip conversions that don't change the signedness.
11095 Note that this is done as an internal manipulation within the
11096 constant folder, in order to find the simplest representation of
11097 the arguments so that their form can be studied. In any cases,
11098 the appropriate type conversions should be put back in the tree
11099 that will get out of the constant folder. */
11101 {
11104 }
11107 {
11110 }
11113 {
11116 }
11119 {
11123 {
11129 }
11134 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11135 so all simple results must be passed through pedantic_non_lvalue. */
11137 {
11140 /* Only optimize constant conditions when the selected branch
11141 has the same type as the COND_EXPR. This avoids optimizing
11142 away "c ? x : throw", where the throw has a void type.
11143 Avoid throwing away that operand which contains label. */
11150 }
11152 {
11157 {
11162 {
11170 }
11174 }
11175 }
11177 /* If we have A op B ? A : C, we may be able to convert this to a
11178 simpler expression, depending on the operation and the values
11179 of B and C. Signed zeros prevent all of these transformations,
11180 for reasons given above each one.
11182 Also try swapping the arguments and inverting the conditional. */
11186 {
11190 }
11195 {
11199 {
11203 }
11204 }
11206 /* If the second operand is simpler than the third, swap them
11207 since that produces better jump optimization results. */
11210 {
11212 /* See if this can be inverted. If it can't, possibly because
11213 it was a floating-point inequality comparison, don't do
11214 anything. */
11218 }
11220 /* Convert A ? 1 : 0 to simply A. */
11225 /* If we try to convert OP0 to our type, the
11226 call to fold will try to move the conversion inside
11227 a COND, which will recurse. In that case, the COND_EXPR
11228 is probably the best choice, so leave it alone. */
11232 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11233 over COND_EXPR in cases such as floating point comparisons. */
11242 arg0)));
11244 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11249 {
11250 /* sign_bit_p looks through both zero and sign extensions,
11251 but for this optimization only sign extensions are
11252 usable. */
11255 {
11258 {
11261 }
11263 }
11264 /* sign_bit_p only checks ARG1 bits within A's precision.
11265 If <sign bit of A> has wider type than A, bits outside
11266 of A's precision in <sign bit of A> need to be checked.
11267 If they are all 0, this optimization needs to be done
11268 in unsigned A's type, if they are all 1 in signed A's type,
11269 otherwise this can't be done. */
11275 {
11277 tree tem_type;
11290 {
11293 }
11295 {
11298 }
11299 else
11301 }
11304 return
11310 arg1)));
11311 }
11313 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11314 already handled above. */
11319 {
11329 op1);
11330 }
11332 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11333 is probably obsolete because the first operand should be a
11334 truth value (that's why we have the two cases above), but let's
11335 leave it in until we can confirm this for all front-ends. */
11347 /* Disable the transformations below for vectors, since
11348 fold_binary_op_with_conditional_arg may undo them immediately,
11349 yielding an infinite loop. */
11353 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11362 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11367 {
11369 /* Only perform transformation if ARG0 is easily inverted. */
11373 ? BIT_IOR_EXPR
11376 op1);
11377 }
11379 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11384 {
11386 /* Only perform transformation if ARG0 is easily inverted. */
11392 op2);
11393 }
11395 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11407 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11408 of fold_ternary on them. */
11416 {
11426 {
11431 {
11439 }
11440 }
11441 }
11443 /* On constants we can use native encode/interpret to constant
11444 fold (nearly) all BIT_FIELD_REFs. */
11448 {
11451 /* Limit us to a reasonable amount of work. To relax the
11452 other limitations we need bit-shifting of the buffer
11453 and rounding up the size. */
11457 {
11459 unsigned HOST_WIDE_INT len
11464 {
11469 }
11470 }
11471 }
11476 /* For integers we can decompose the FMA if possible. */
11488 {
11504 {
11509 /* Make sure that the perm value is in an acceptable
11510 range. */
11519 else
11527 }
11530 {
11535 }
11540 {
11545 }
11551 {
11555 }
11560 /* Some targets are deficient and fail to expand a single
11561 argument permutation while still allowing an equivalent
11562 2-argument version. */
11566 {
11569 }
11572 {
11579 }
11583 }
11587 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11590 {
11596 wide_int tem2
11600 }
11605 {
11607 unsigned HOST_WIDE_INT elsize
11610 {
11614 else
11615 {
11623 }
11624 }
11625 }
11631 }
11633 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11634 of an array (or vector). */
11636 tree
11638 {
11643 {
11646 {
11647 /* Static constructors for variably sized objects makes no sense. */
11651 }
11652 }
11663 offset_int max_index;
11668 {
11669 /* Array constructor might explicitly set index, or specify a range,
11670 or leave index NULL meaning that it is next index after previous
11671 one. */
11673 {
11676 else
11677 {
11681 }
11682 }
11683 else
11684 {
11690 }
11692 /* Do we have match? */
11696 }
11698 }
11700 /* Perform constant folding and related simplification of EXPR.
11701 The related simplifications include x*1 => x, x*0 => 0, etc.,
11702 and application of the associative law.
11703 NOP_EXPR conversions may be removed freely (as long as we
11704 are careful not to change the type of the overall expression).
11705 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11706 but we can constant-fold them if they have constant operands. */
11708 #ifdef ENABLE_FOLD_CHECKING
11709 # define fold(x) fold_1 (x)
11711 static
11712 #endif
11713 tree
11715 {
11719 tree tem;
11722 /* Return right away if a constant. */
11726 /* CALL_EXPR-like objects with variable numbers of operands are
11727 treated specially. */
11729 {
11731 {
11734 }
11736 }
11739 {
11744 {
11762 }
11763 }
11766 {
11768 {
11775 {
11780 }
11783 }
11785 /* Return a VECTOR_CST if possible. */
11787 {
11793 tree val;
11799 }
11807 }
11809 #ifdef ENABLE_FOLD_CHECKING
11810 #undef fold
11817 /* When --enable-checking=fold, compute a digest of expr before
11818 and after actual fold call to see if fold did not accidentally
11819 change original expr. */
11821 tree
11823 {
11824 tree ret;
11844 }
11846 void
11848 {
11859 }
11861 static void
11863 {
11865 }
11867 static void
11870 {
11876 recursive_label:
11886 {
11887 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
11892 }
11900 {
11901 /* Allow these fields to be modified. */
11902 tree tmp;
11911 {
11914 }
11915 }
11926 {
11929 {
11944 }
11948 {
11961 }
11978 {
11984 }
11987 {
11989 {
11992 }
11994 }
12005 {
12008 }
12018 }
12019 }
12021 /* Helper function for outputting the checksum of a tree T. When
12022 debugging with gdb, you can "define mynext" to be "next" followed
12023 by "call debug_fold_checksum (op0)", then just trace down till the
12024 outputs differ. */
12026 DEBUG_FUNCTION void
12028 {
12043 }
12045 #endif
12047 /* Fold a unary tree expression with code CODE of type TYPE with an
12048 operand OP0. LOC is the location of the resulting expression.
12049 Return a folded expression if successful. Otherwise, return a tree
12050 expression with code CODE of type TYPE with an operand OP0. */
12052 tree
12055 {
12056 tree tem;
12057 #ifdef ENABLE_FOLD_CHECKING
12066 #endif
12072 #ifdef ENABLE_FOLD_CHECKING
12079 #endif
12081 }
12083 /* Fold a binary tree expression with code CODE of type TYPE with
12084 operands OP0 and OP1. LOC is the location of the resulting
12085 expression. Return a folded expression if successful. Otherwise,
12086 return a tree expression with code CODE of type TYPE with operands
12087 OP0 and OP1. */
12089 tree
12092 MEM_STAT_DECL)
12093 {
12094 tree tem;
12095 #ifdef ENABLE_FOLD_CHECKING
12112 #endif
12118 #ifdef ENABLE_FOLD_CHECKING
12133 #endif
12135 }
12137 /* Fold a ternary tree expression with code CODE of type TYPE with
12138 operands OP0, OP1, and OP2. Return a folded expression if
12139 successful. Otherwise, return a tree expression with code CODE of
12140 type TYPE with operands OP0, OP1, and OP2. */
12142 tree
12145 {
12146 tree tem;
12147 #ifdef ENABLE_FOLD_CHECKING
12171 #endif
12178 #ifdef ENABLE_FOLD_CHECKING
12201 #endif
12203 }
12205 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12206 arguments in ARGARRAY, and a null static chain.
12207 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12208 of type TYPE from the given operands as constructed by build_call_array. */
12210 tree
12213 {
12214 tree tem;
12215 #ifdef ENABLE_FOLD_CHECKING
12234 #endif
12240 #ifdef ENABLE_FOLD_CHECKING
12256 #endif
12258 }
12260 /* Perform constant folding and related simplification of initializer
12261 expression EXPR. These behave identically to "fold_buildN" but ignore
12262 potential run-time traps and exceptions that fold must preserve. */
12264 #define START_FOLD_INIT \
12265 int saved_signaling_nans = flag_signaling_nans;\
12266 int saved_trapping_math = flag_trapping_math;\
12267 int saved_rounding_math = flag_rounding_math;\
12268 int saved_trapv = flag_trapv;\
12269 int saved_folding_initializer = folding_initializer;\
12270 flag_signaling_nans = 0;\
12271 flag_trapping_math = 0;\
12272 flag_rounding_math = 0;\
12273 flag_trapv = 0;\
12274 folding_initializer = 1;
12276 #define END_FOLD_INIT \
12277 flag_signaling_nans = saved_signaling_nans;\
12278 flag_trapping_math = saved_trapping_math;\
12279 flag_rounding_math = saved_rounding_math;\
12280 flag_trapv = saved_trapv;\
12281 folding_initializer = saved_folding_initializer;
12283 tree
12286 {
12287 tree result;
12288 START_FOLD_INIT;
12292 END_FOLD_INIT;
12294 }
12296 tree
12299 {
12300 tree result;
12301 START_FOLD_INIT;
12305 END_FOLD_INIT;
12307 }
12309 tree
12312 {
12313 tree result;
12314 START_FOLD_INIT;
12318 END_FOLD_INIT;
12320 }
12322 #undef START_FOLD_INIT
12323 #undef END_FOLD_INIT
12325 /* Determine if first argument is a multiple of second argument. Return 0 if
12326 it is not, or we cannot easily determined it to be.
12328 An example of the sort of thing we care about (at this point; this routine
12329 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12330 fold cases do now) is discovering that
12332 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12334 is a multiple of
12336 SAVE_EXPR (J * 8)
12338 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12340 This code also handles discovering that
12342 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12344 is a multiple of 8 so we don't have to worry about dealing with a
12345 possible remainder.
12347 Note that we *look* inside a SAVE_EXPR only to determine how it was
12348 calculated; it is not safe for fold to do much of anything else with the
12349 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12350 at run time. For example, the latter example above *cannot* be implemented
12351 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12352 evaluation time of the original SAVE_EXPR is not necessarily the same at
12353 the time the new expression is evaluated. The only optimization of this
12354 sort that would be valid is changing
12356 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12358 divided by 8 to
12360 SAVE_EXPR (I) * SAVE_EXPR (J)
12362 (where the same SAVE_EXPR (J) is used in the original and the
12363 transformed version). */
12365 int
12367 {
12378 {
12380 /* Bitwise and provides a power of two multiple. If the mask is
12381 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12384 /* FALLTHRU */
12391 /* It is impossible to prove if op0 - op1 is multiple of bottom
12392 precisely, so be conservative here checking if both op0 and op1
12393 are multiple of bottom. Note we check the second operand first
12394 since it's usually simpler. */
12399 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12400 as op0 - 3 if the expression has unsigned type. For example,
12401 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12411 {
12413 /* const_binop may not detect overflow correctly,
12414 so check for it explicitly here. */
12419 size_one_node,
12420 op1)))
12423 }
12427 /* Can't handle conversions from non-integral or wider integral type. */
12433 /* fall through */
12450 SIGNED);
12456 {
12459 /* Check for special cases to see if top is defined as multiple
12460 of bottom:
12462 top = (X & ~(bottom - 1) ; bottom is power of 2
12464 or
12466 Y = X % bottom
12467 top = X - Y. */
12486 }
12488 /* fall through */
12492 }
12493 }
12495 #define tree_expr_nonnegative_warnv_p(X, Y) \
12498 #define RECURSE(X) \
12499 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12501 /* Return true if CODE or TYPE is known to be non-negative. */
12503 static bool
12505 {
12508 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12509 have a signed:1 type (where the value is -1 and 0). */
12512 }
12514 /* Return true if (CODE OP0) is known to be non-negative. If the return
12515 value is based on the assumption that signed overflow is undefined,
12516 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12517 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12519 bool
12522 {
12527 {
12529 /* We can't return 1 if flag_wrapv is set because
12530 ABS_EXPR<INT_MIN> = INT_MIN. */
12534 {
12537 }
12545 CASE_CONVERT:
12546 {
12551 {
12555 {
12559 }
12560 }
12562 {
12568 }
12569 }
12574 }
12576 /* We don't know sign of `t', so be conservative and return false. */
12578 }
12580 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12581 value is based on the assumption that signed overflow is undefined,
12582 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12583 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12585 bool
12589 {
12594 {
12600 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12601 both unsigned and at least 2 bits shorter than the result. */
12605 {
12610 {
12614 }
12615 }
12620 {
12621 /* x * x is always non-negative for floating point x
12622 or without overflow. */
12625 {
12630 }
12631 }
12633 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12634 both unsigned and their total bits is shorter than the result. */
12638 {
12657 {
12667 }
12668 }
12695 }
12697 /* We don't know sign of `t', so be conservative and return false. */
12699 }
12701 /* Return true if T is known to be non-negative. If the return
12702 value is based on the assumption that signed overflow is undefined,
12703 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12704 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12706 bool
12708 {
12713 {
12727 /* Limit the depth of recursion to avoid quadratic behavior.
12728 This is expected to catch almost all occurrences in practice.
12729 If this code misses important cases that unbounded recursion
12730 would not, passes that need this information could be revised
12731 to provide it through dataflow propagation. */
12739 }
12740 }
12742 /* Return true if T is known to be non-negative. If the return
12743 value is based on the assumption that signed overflow is undefined,
12744 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12745 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12747 bool
12750 {
12752 {
12753 CASE_CFN_ACOS:
12754 CASE_CFN_ACOSH:
12755 CASE_CFN_CABS:
12756 CASE_CFN_COSH:
12757 CASE_CFN_ERFC:
12758 CASE_CFN_EXP:
12759 CASE_CFN_EXP10:
12760 CASE_CFN_EXP2:
12761 CASE_CFN_FABS:
12762 CASE_CFN_FDIM:
12763 CASE_CFN_HYPOT:
12764 CASE_CFN_POW10:
12765 CASE_CFN_FFS:
12766 CASE_CFN_PARITY:
12767 CASE_CFN_POPCOUNT:
12768 CASE_CFN_CLZ:
12769 CASE_CFN_CLRSB:
12772 /* Always true. */
12775 CASE_CFN_SQRT:
12776 CASE_CFN_SQRT_FN:
12777 /* sqrt(-0.0) is -0.0. */
12782 CASE_CFN_ASINH:
12783 CASE_CFN_ATAN:
12784 CASE_CFN_ATANH:
12785 CASE_CFN_CBRT:
12786 CASE_CFN_CEIL:
12787 CASE_CFN_ERF:
12788 CASE_CFN_EXPM1:
12789 CASE_CFN_FLOOR:
12790 CASE_CFN_FMOD:
12791 CASE_CFN_FREXP:
12792 CASE_CFN_ICEIL:
12793 CASE_CFN_IFLOOR:
12794 CASE_CFN_IRINT:
12795 CASE_CFN_IROUND:
12796 CASE_CFN_LCEIL:
12797 CASE_CFN_LDEXP:
12798 CASE_CFN_LFLOOR:
12799 CASE_CFN_LLCEIL:
12800 CASE_CFN_LLFLOOR:
12801 CASE_CFN_LLRINT:
12802 CASE_CFN_LLROUND:
12803 CASE_CFN_LRINT:
12804 CASE_CFN_LROUND:
12805 CASE_CFN_MODF:
12806 CASE_CFN_NEARBYINT:
12807 CASE_CFN_RINT:
12808 CASE_CFN_ROUND:
12809 CASE_CFN_SCALB:
12810 CASE_CFN_SCALBLN:
12811 CASE_CFN_SCALBN:
12812 CASE_CFN_SIGNBIT:
12813 CASE_CFN_SIGNIFICAND:
12814 CASE_CFN_SINH:
12815 CASE_CFN_TANH:
12816 CASE_CFN_TRUNC:
12817 /* True if the 1st argument is nonnegative. */
12820 CASE_CFN_FMAX:
12821 CASE_CFN_FMAX_FN:
12822 /* True if the 1st OR 2nd arguments are nonnegative. */
12825 CASE_CFN_FMIN:
12826 CASE_CFN_FMIN_FN:
12827 /* True if the 1st AND 2nd arguments are nonnegative. */
12830 CASE_CFN_COPYSIGN:
12831 CASE_CFN_COPYSIGN_FN:
12832 /* True if the 2nd argument is nonnegative. */
12835 CASE_CFN_POWI:
12836 /* True if the 1st argument is nonnegative or the second
12837 argument is an even integer. */
12843 CASE_CFN_POW:
12844 /* True if the 1st argument is nonnegative or the second
12845 argument is an even integer valued real. */
12847 {
12848 REAL_VALUE_TYPE c;
12849 HOST_WIDE_INT n;
12854 {
12855 REAL_VALUE_TYPE cint;
12859 }
12860 }
12865 }
12867 }
12869 /* Return true if T is known to be non-negative. If the return
12870 value is based on the assumption that signed overflow is undefined,
12871 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12872 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12874 static bool
12876 {
12882 {
12884 {
12888 /* If the initializer is non-void, then it's a normal expression
12889 that will be assigned to the slot. */
12893 /* Otherwise, the initializer sets the slot in some way. One common
12894 way is an assignment statement at the end of the initializer. */
12896 {
12904 else
12906 }
12912 }
12915 {
12921 arg0,
12922 arg1,
12924 }
12937 }
12938 }
12940 #undef RECURSE
12941 #undef tree_expr_nonnegative_warnv_p
12943 /* Return true if T is known to be non-negative. If the return
12944 value is based on the assumption that signed overflow is undefined,
12945 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12946 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12948 bool
12950 {
12957 {
12979 }
12982 {
13008 }
13009 }
13011 /* Return true if `t' is known to be non-negative. Handle warnings
13012 about undefined signed overflow. */
13014 bool
13016 {
13023 "determining that expression is always "
13025 WARN_STRICT_OVERFLOW_MISC);
13027 }
13030 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13031 For floating point we further ensure that T is not denormal.
13032 Similar logic is present in nonzero_address in rtlanal.h.
13034 If the return value is based on the assumption that signed overflow
13035 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13036 change *STRICT_OVERFLOW_P. */
13038 bool
13041 {
13043 {
13046 strict_overflow_p);
13049 {
13055 strict_overflow_p));
13056 }
13061 strict_overflow_p);
13065 }
13068 }
13070 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13071 For floating point we further ensure that T is not denormal.
13072 Similar logic is present in nonzero_address in rtlanal.h.
13074 If the return value is based on the assumption that signed overflow
13075 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13076 change *STRICT_OVERFLOW_P. */
13078 bool
13080 tree type,
13081 tree op0,
13083 {
13086 {
13090 {
13091 /* With the presence of negative values it is hard
13092 to say something. */
13099 /* One of operands must be positive and the other non-negative. */
13100 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13101 overflows, on a twos-complement machine the sum of two
13102 nonnegative numbers can never be zero. */
13104 strict_overflow_p)
13106 strict_overflow_p));
13107 }
13112 {
13114 strict_overflow_p)
13116 strict_overflow_p))
13117 {
13120 }
13121 }
13130 {
13133 }
13140 {
13144 /* When both operands are nonzero, then MAX must be too. */
13146 strict_overflow_p))
13149 /* MAX where operand 0 is positive is positive. */
13151 strict_overflow_p);
13152 }
13153 /* MAX where operand 1 is positive is positive. */
13158 {
13162 }
13167 strict_overflow_p)
13169 strict_overflow_p));
13173 }
13176 }
13178 /* Return true when T is an address and is known to be nonzero.
13179 For floating point we further ensure that T is not denormal.
13180 Similar logic is present in nonzero_address in rtlanal.h.
13182 If the return value is based on the assumption that signed overflow
13183 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13184 change *STRICT_OVERFLOW_P. */
13186 bool
13188 {
13191 {
13196 {
13208 /* For objects in symbol table check if we know they are non-zero.
13209 Don't do anything for variables and functions before symtab is built;
13210 it is quite possible that they will be declared weak later. */
13215 /* Constants are never weak. */
13220 }
13228 {
13232 }
13242 }
13244 }
13246 #define integer_valued_real_p(X) \
13249 #define RECURSE(X) \
13250 ((integer_valued_real_p) (X, depth + 1))
13252 /* Return true if the floating point result of (CODE OP0) has an
13253 integer value. We also allow +Inf, -Inf and NaN to be considered
13254 integer values. Return false for signaling NaN.
13256 DEPTH is the current nesting depth of the query. */
13258 bool
13260 {
13262 {
13269 CASE_CONVERT:
13270 {
13277 }
13281 }
13283 }
13285 /* Return true if the floating point result of (CODE OP0 OP1) has an
13286 integer value. We also allow +Inf, -Inf and NaN to be considered
13287 integer values. Return false for signaling NaN.
13289 DEPTH is the current nesting depth of the query. */
13291 bool
13293 {
13295 {
13305 }
13307 }
13309 /* Return true if the floating point result of calling FNDECL with arguments
13310 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13311 considered integer values. Return false for signaling NaN. If FNDECL
13312 takes fewer than 2 arguments, the remaining ARGn are null.
13314 DEPTH is the current nesting depth of the query. */
13316 bool
13318 {
13320 {
13321 CASE_CFN_CEIL:
13322 CASE_CFN_FLOOR:
13323 CASE_CFN_NEARBYINT:
13324 CASE_CFN_RINT:
13325 CASE_CFN_ROUND:
13326 CASE_CFN_TRUNC:
13329 CASE_CFN_FMIN:
13330 CASE_CFN_FMIN_FN:
13331 CASE_CFN_FMAX:
13332 CASE_CFN_FMAX_FN:
13337 }
13339 }
13341 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13342 has an integer value. We also allow +Inf, -Inf and NaN to be
13343 considered integer values. Return false for signaling NaN.
13345 DEPTH is the current nesting depth of the query. */
13347 bool
13349 {
13351 {
13359 /* Limit the depth of recursion to avoid quadratic behavior.
13360 This is expected to catch almost all occurrences in practice.
13361 If this code misses important cases that unbounded recursion
13362 would not, passes that need this information could be revised
13363 to provide it through dataflow propagation. */
13367 depth));
13371 }
13373 }
13375 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13376 has an integer value. We also allow +Inf, -Inf and NaN to be
13377 considered integer values. Return false for signaling NaN.
13379 DEPTH is the current nesting depth of the query. */
13381 static bool
13383 {
13385 {
13396 }
13398 }
13400 #undef RECURSE
13401 #undef integer_valued_real_p
13403 /* Return true if the floating point expression T has an integer value.
13404 We also allow +Inf, -Inf and NaN to be considered integer values.
13405 Return false for signaling NaN.
13407 DEPTH is the current nesting depth of the query. */
13409 bool
13411 {
13417 {
13433 }
13436 {
13442 {
13451 }
13455 }
13456 }
13458 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13459 attempt to fold the expression to a constant without modifying TYPE,
13460 OP0 or OP1.
13462 If the expression could be simplified to a constant, then return
13463 the constant. If the expression would not be simplified to a
13464 constant, then return NULL_TREE. */
13466 tree
13468 {
13471 }
13473 /* Given the components of a unary expression CODE, TYPE and OP0,
13474 attempt to fold the expression to a constant without modifying
13475 TYPE or OP0.
13477 If the expression could be simplified to a constant, then return
13478 the constant. If the expression would not be simplified to a
13479 constant, then return NULL_TREE. */
13481 tree
13483 {
13486 }
13488 /* If EXP represents referencing an element in a constant string
13489 (either via pointer arithmetic or array indexing), return the
13490 tree representing the value accessed, otherwise return NULL. */
13492 tree
13494 {
13498 {
13500 tree index;
13501 tree string;
13506 else
13507 {
13511 /* Optimize the special-case of a zero lower bound.
13513 We convert the low_bound to sizetype to avoid some problems
13514 with constant folding. (E.g. suppose the lower bound is 1,
13515 and its mode is QI. Without the conversion,l (ARRAY
13516 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13517 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13523 }
13525 scalar_int_mode char_mode;
13537 }
13539 }
13541 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13542 an integer constant, real, or fixed-point constant.
13544 TYPE is the type of the result. */
13546 static tree
13548 {
13552 {
13554 {
13561 }
13568 {
13569 FIXED_VALUE_TYPE f;
13574 /* Propagate overflow flags. */
13578 }
13582 }
13585 }
13587 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13588 an integer constant or real constant.
13590 TYPE is the type of the result. */
13592 tree
13594 {
13598 {
13600 {
13601 /* If the value is unsigned or non-negative, then the absolute value
13602 is the same as the ordinary value. */
13606 /* If the value is negative, then the absolute value is
13607 its negation. */
13608 else
13609 {
13614 }
13615 }
13621 else
13627 }
13630 }
13632 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13633 constant. TYPE is the type of the result. */
13635 static tree
13637 {
13641 }
13643 /* Given CODE, a relational operator, the target type, TYPE and two
13644 constant operands OP0 and OP1, return the result of the
13645 relational operation. If the result is not a compile time
13646 constant, then return NULL_TREE. */
13648 static tree
13650 {
13653 /* From here on, the only cases we handle are when the result is
13654 known to be a constant. */
13657 {
13661 /* Handle the cases where either operand is a NaN. */
13663 {
13665 {
13693 }
13696 }
13699 }
13702 {
13706 }
13708 /* Handle equality/inequality of complex constants. */
13710 {
13721 else
13723 }
13726 {
13728 {
13729 /* Have vector comparison with scalar boolean result. */
13733 {
13741 }
13743 }
13750 {
13763 }
13766 }
13768 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13770 To compute GT, swap the arguments and do LT.
13771 To compute GE, do LT and invert the result.
13772 To compute LE, swap the arguments, do LT and invert the result.
13773 To compute NE, do EQ and invert the result.
13775 Therefore, the code below must handle only EQ and LT. */
13778 {
13781 }
13783 /* Note that it is safe to invert for real values here because we
13784 have already handled the one case that it matters. */
13788 {
13791 }
13793 /* Compute a result for LT or EQ if args permit;
13794 Otherwise return T. */
13796 {
13799 else
13801 }
13802 else
13808 }
13810 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13811 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13812 itself. */
13814 tree
13816 {
13817 /* If the expression does not have side effects then we don't have to wrap
13818 it with a cleanup point expression. */
13822 /* If the expression is a return, check to see if the expression inside the
13823 return has no side effects or the right hand side of the modify expression
13824 inside the return. If either don't have side effects set we don't need to
13825 wrap the expression in a cleanup point expression. Note we don't check the
13826 left hand side of the modify because it should always be a return decl. */
13828 {
13835 }
13838 }
13840 /* Given a pointer value OP0 and a type TYPE, return a simplified version
13841 of an indirection through OP0, or NULL_TREE if no simplification is
13842 possible. */
13844 tree
13846 {
13848 tree subtype;
13857 {
13860 /* *&CONST_DECL -> to the value of the const decl. */
13863 /* *&p => p; make sure to handle *&"str"[cst] here. */
13865 {
13869 else
13871 }
13872 /* *(foo *)&fooarray => fooarray[0] */
13875 && (!in_gimple_form
13877 {
13887 }
13888 /* *(foo *)&complexfoo => __real__ complexfoo */
13892 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
13895 {
13899 }
13900 }
13904 {
13910 {
13911 tree op00type;
13915 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
13918 {
13920 unsigned HOST_WIDE_INT max_offset
13925 {
13932 }
13933 }
13934 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
13937 {
13941 }
13942 /* ((foo *)&fooarray)[1] => fooarray[1] */
13945 {
13952 offset_int remainder;
13955 {
13960 }
13961 }
13962 }
13963 }
13965 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
13968 && (!in_gimple_form
13970 {
13971 tree type_domain;
13981 NULL_TREE);
13982 }
13985 }
13987 /* Builds an expression for an indirection through T, simplifying some
13988 cases. */
13990 tree
13992 {
14000 }
14002 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14004 tree
14006 {
14011 else
14013 }
14015 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14016 whose result is ignored. The type of the returned tree need not be
14017 the same as the original expression. */
14019 tree
14021 {
14027 {
14038 else
14044 {
14060 }
14065 }
14066 }
14068 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14070 tree
14072 {
14078 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14079 have to do anything. Only do this when we are not given a const,
14080 because in that case, this check is more expensive than just
14081 doing it. */
14083 {
14088 }
14090 /* If divisor is a power of two, simplify this to bit manipulation. */
14092 {
14094 {
14108 }
14109 else
14110 {
14111 tree t;
14117 }
14118 }
14119 else
14120 {
14125 }
14128 }
14130 /* Likewise, but round down. */
14132 tree
14134 {
14141 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14142 have to do anything. Only do this when we are not given a const,
14143 because in that case, this check is more expensive than just
14144 doing it. */
14146 {
14151 }
14153 /* If divisor is a power of two, simplify this to bit manipulation. */
14155 {
14156 tree t;
14160 }
14161 else
14162 {
14167 }
14170 }
14172 /* Returns the pointer to the base of the object addressed by EXP and
14173 extracts the information about the offset of the access, storing it
14174 to PBITPOS and POFFSET. */
14176 static tree
14179 {
14180 tree core;
14181 machine_mode mode;
14183 HOST_WIDE_INT bitsize;
14187 {
14192 }
14194 {
14200 {
14205 {
14208 }
14209 }
14210 }
14211 else
14212 {
14216 }
14219 }
14221 /* Returns true if addresses of E1 and E2 differ by a constant, false
14222 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14224 bool
14226 {
14240 {
14250 }
14252 {
14253 /* If only one of the offsets is non-constant, the difference cannot
14254 be a constant. */
14256 }
14257 else
14262 }
14264 /* Return OFF converted to a pointer offset type suitable as offset for
14265 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14266 tree
14268 {
14270 }
14272 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14273 tree
14275 {
14278 }
14280 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14281 tree
14283 {
14286 }
14288 /* Return a char pointer for a C string if it is a string constant
14289 or sum of string constant and integer constant. We only support
14290 string constants properly terminated with '\0' character.
14291 If STRLEN is a valid pointer, length (including terminating character)
14292 of returned string is stored to the argument. */
14296 {
14297 tree offset_node;
14308 {
14311 else
14313 }
14318 /* Support only properly null-terminated strings. */
14327 }
14329 #if CHECKING_P
14333 /* Helper functions for writing tests of folding trees. */
14335 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14337 static void
14339 tree constant)
14340 {
14342 }
14344 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14345 wrapping WRAPPED_EXPR. */
14347 static void
14349 tree wrapped_expr)
14350 {
14355 }
14357 /* Verify that various arithmetic binary operations are folded
14358 correctly. */
14360 static void
14362 {
14368 /* Addition. */
14369 /* 1 <-- (0 + 1) */
14371 one);
14373 one);
14375 /* (nonlvalue)x <-- (x + 0) */
14377 x);
14379 /* Subtraction. */
14380 /* 0 <-- (x - x) */
14382 zero);
14384 x);
14386 /* Multiplication. */
14387 /* 0 <-- (x * 0) */
14389 zero);
14391 /* (nonlvalue)x <-- (x * 1) */
14393 x);
14394 }
14396 /* Verify that various binary operations on vectors are folded
14397 correctly. */
14399 static void
14401 {
14407 /* Verify equality tests that return a scalar boolean result. */
14413 }
14415 /* Run all of the selftests within this file. */
14417 void
14419 {
14422 }