| blob | b9f2a39ee853e6071e39783f5bb3d7a68166b85e |
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 };
143 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
144 Otherwise, return LOC. */
146 static location_t
148 {
151 }
153 /* Similar to protected_set_expr_location, but never modify x in place,
154 if location can and needs to be set, unshare it. */
158 {
164 {
167 }
169 }
170 \f
171 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
172 division and returns the quotient. Otherwise returns
173 NULL_TREE. */
175 tree
177 {
178 widest_int quo;
185 }
186 \f
187 /* This is nonzero if we should defer warnings about undefined
188 overflow. This facility exists because these warnings are a
189 special case. The code to estimate loop iterations does not want
190 to issue any warnings, since it works with expressions which do not
191 occur in user code. Various bits of cleanup code call fold(), but
192 only use the result if it has certain characteristics (e.g., is a
193 constant); that code only wants to issue a warning if the result is
194 used. */
198 /* If a warning about undefined overflow is deferred, this is the
199 warning. Note that this may cause us to turn two warnings into
200 one, but that is fine since it is sufficient to only give one
201 warning per expression. */
205 /* If a warning about undefined overflow is deferred, this is the
206 level at which the warning should be emitted. */
210 /* Start deferring overflow warnings. We could use a stack here to
211 permit nested calls, but at present it is not necessary. */
213 void
215 {
217 }
219 /* Stop deferring overflow warnings. If there is a pending warning,
220 and ISSUE is true, then issue the warning if appropriate. STMT is
221 the statement with which the warning should be associated (used for
222 location information); STMT may be NULL. CODE is the level of the
223 warning--a warn_strict_overflow_code value. This function will use
224 the smaller of CODE and the deferred code when deciding whether to
225 issue the warning. CODE may be zero to mean to always use the
226 deferred code. */
228 void
230 {
232 location_t locus;
237 {
243 }
254 /* Use the smallest code level when deciding to issue the
255 warning. */
264 else
267 }
269 /* Stop deferring overflow warnings, ignoring any deferred
270 warnings. */
272 void
274 {
276 }
278 /* Whether we are deferring overflow warnings. */
280 bool
282 {
284 }
286 /* This is called when we fold something based on the fact that signed
287 overflow is undefined. */
289 void
291 {
293 {
296 {
299 }
300 }
303 }
304 \f
305 /* Return true if the built-in mathematical function specified by CODE
306 is odd, i.e. -f(x) == f(-x). */
308 bool
310 {
312 {
313 CASE_CFN_ASIN:
314 CASE_CFN_ASINH:
315 CASE_CFN_ATAN:
316 CASE_CFN_ATANH:
317 CASE_CFN_CASIN:
318 CASE_CFN_CASINH:
319 CASE_CFN_CATAN:
320 CASE_CFN_CATANH:
321 CASE_CFN_CBRT:
322 CASE_CFN_CPROJ:
323 CASE_CFN_CSIN:
324 CASE_CFN_CSINH:
325 CASE_CFN_CTAN:
326 CASE_CFN_CTANH:
327 CASE_CFN_ERF:
328 CASE_CFN_LLROUND:
329 CASE_CFN_LROUND:
330 CASE_CFN_ROUND:
331 CASE_CFN_SIN:
332 CASE_CFN_SINH:
333 CASE_CFN_TAN:
334 CASE_CFN_TANH:
335 CASE_CFN_TRUNC:
338 CASE_CFN_LLRINT:
339 CASE_CFN_LRINT:
340 CASE_CFN_NEARBYINT:
341 CASE_CFN_RINT:
346 }
348 }
350 /* Check whether we may negate an integer constant T without causing
351 overflow. */
353 bool
355 {
356 tree type;
365 }
367 /* Determine whether an expression T can be cheaply negated using
368 the function negate_expr without introducing undefined overflow. */
370 static bool
372 {
373 tree type;
382 {
387 /* Check that -CST will not overflow type. */
400 /* We want to canonicalize to positive real constants. Pretend
401 that only negative ones can be easily negated. */
409 {
420 }
435 /* -(A + B) -> (-B) - A. */
438 /* -(A + B) -> (-A) - B. */
442 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
451 /* INT_MIN/n * n doesn't overflow while negating one operand it does
452 if n is a (negative) power of two. */
461 /* Fall through. */
476 /* In general we can't negate B in A / B, because if A is INT_MIN and
477 B is 1, we may turn this into INT_MIN / -1 which is undefined
478 and actually traps on some architectures. */
487 /* Negate -((double)float) as (double)(-float). */
489 {
493 }
497 /* Negate -f(x) as f(-x). */
503 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
505 {
509 }
514 }
516 }
518 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
519 simplification is possible.
520 If negate_expr_p would return true for T, NULL_TREE will never be
521 returned. */
523 static tree
525 {
527 tree tem;
530 {
531 /* Convert - (~A) to A + 1. */
557 {
562 }
566 {
571 {
575 }
578 }
601 {
602 /* -(A + B) -> (-B) - A. */
604 {
608 }
610 /* -(A + B) -> (-A) - B. */
612 {
616 }
617 }
621 /* - (A - B) -> B - A */
632 /* Fall through. */
636 {
645 }
657 /* In general we can't negate B in A / B, because if A is INT_MIN and
658 B is 1, we may turn this into INT_MIN / -1 which is undefined
659 and actually traps on some architectures. */
671 /* Convert -((double)float) into (double)(-float). */
673 {
677 }
681 /* Negate -f(x) as f(-x). */
684 {
690 }
694 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
696 {
699 {
706 }
707 }
712 }
715 }
717 /* A wrapper for fold_negate_expr_1. */
719 static tree
721 {
728 }
730 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
731 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
732 return NULL_TREE. */
734 static tree
736 {
738 location_t loc;
751 }
752 \f
753 /* Split a tree IN into a constant, literal and variable parts that could be
754 combined with CODE to make IN. "constant" means an expression with
755 TREE_CONSTANT but that isn't an actual constant. CODE must be a
756 commutative arithmetic operation. Store the constant part into *CONP,
757 the literal in *LITP and return the variable part. If a part isn't
758 present, set it to null. If the tree does not decompose in this way,
759 return the entire tree as the variable part and the other parts as null.
761 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
762 case, we negate an operand that was subtracted. Except if it is a
763 literal for which we use *MINUS_LITP instead.
765 If NEGATE_P is true, we are negating all of IN, again except a literal
766 for which we use *MINUS_LITP instead. If a variable part is of pointer
767 type, it is negated after converting to TYPE. This prevents us from
768 generating illegal MINUS pointer expression. LOC is the location of
769 the converted variable part.
771 If IN is itself a literal or constant, return it as appropriate.
773 Note that we do not guarantee that any of the three values will be the
774 same type as IN, but they will have the same signedness and mode. */
776 static tree
780 {
788 /* Strip any conversions that don't change the machine mode or signedness. */
797 /* We can associate addition and subtraction together (even
798 though the C standard doesn't say so) for integers because
799 the value is not affected. For reals, the value might be
800 affected, so we can't. */
806 {
812 /* First see if either of the operands is a literal, then a constant. */
825 /* If we haven't dealt with either operand, this is not a case we can
826 decompose. Otherwise, VAR is either of the ones remaining, if any. */
831 else
834 /* Now do any needed negations. */
841 }
846 {
847 /* -1 - X is folded to ~X, undo that here. Do _not_ do this
848 when IN is constant. */
851 }
852 else
856 {
869 }
879 }
881 /* Re-associate trees split by the above function. T1 and T2 are
882 either expressions to associate or null. Return the new
883 expression, if any. LOC is the location of the new expression. If
884 we build an operation, do it in TYPE and with CODE. */
886 static tree
888 {
890 {
893 }
897 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
898 try to fold this since we will have infinite recursion. But do
899 deal with any NEGATE_EXPRs. */
903 {
905 {
918 }
920 {
923 }
927 }
931 }
932 \f
933 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
934 for use in int_const_binop, size_binop and size_diffop. */
936 static bool
938 {
945 {
954 }
959 }
962 /* Combine two integer constants ARG1 and ARG2 under operation CODE
963 to produce a new constant. Return NULL_TREE if we don't know how
964 to evaluate CODE at compile-time. */
966 static tree
969 {
970 wide_int res;
971 tree t;
979 {
995 {
999 else
1001 }
1004 /* It's unclear from the C standard whether shifts can overflow.
1005 The following code ignores overflow; perhaps a C standard
1006 interpretation ruling is needed. */
1008 else
1015 {
1019 else
1021 }
1025 else
1104 }
1112 }
1114 tree
1116 {
1118 }
1120 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1121 constant. We assume ARG1 and ARG2 have the same data type, or at least
1122 are the same kind of constant and the same machine mode. Return zero if
1123 combining the constants is not allowed in the current operating mode. */
1125 static tree
1127 {
1128 /* Sanity check for the recursive cases. */
1136 {
1142 }
1145 {
1146 machine_mode mode;
1147 REAL_VALUE_TYPE d1;
1148 REAL_VALUE_TYPE d2;
1149 REAL_VALUE_TYPE value;
1150 REAL_VALUE_TYPE result;
1154 /* The following codes are handled by real_arithmetic. */
1156 {
1167 }
1175 /* Don't perform operation if we honor signaling NaNs and
1176 either operand is a signaling NaN. */
1182 /* Don't perform operation if it would raise a division
1183 by zero exception. */
1189 /* If either operand is a NaN, just return it. Otherwise, set up
1190 for floating-point trap; we return an overflow. */
1192 {
1193 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1194 is off. */
1198 }
1200 {
1201 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1202 is off. */
1206 }
1211 /* Don't constant fold this floating point operation if
1212 the result has overflowed and flag_trapping_math. */
1220 /* Don't constant fold this floating point operation if the
1221 result may dependent upon the run-time rounding mode and
1222 flag_rounding_math is set, or if GCC's software emulation
1223 is unable to accurately represent the result. */
1233 }
1236 {
1237 FIXED_VALUE_TYPE f1;
1238 FIXED_VALUE_TYPE f2;
1239 FIXED_VALUE_TYPE result;
1244 /* The following codes are handled by fixed_arithmetic. */
1246 {
1258 {
1265 }
1270 }
1277 /* Propagate overflow flags. */
1281 }
1284 {
1293 {
1304 mpc_mul);
1318 mpc_div);
1319 /* Fallthru. */
1325 {
1326 /* Keep this algorithm in sync with
1327 tree-complex.c:expand_complex_div_straight().
1329 Expand complex division to scalars, straightforward algorithm.
1330 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1331 t = br*br + bi*bi
1332 */
1333 tree magsquared
1337 tree t1
1341 tree t2
1348 }
1349 else
1350 {
1351 /* Keep this algorithm in sync with
1352 tree-complex.c:expand_complex_div_wide().
1354 Expand complex division to scalars, modified algorithm to minimize
1355 overflow with wide input ranges. */
1361 {
1362 /* In the TRUE branch, we compute
1363 ratio = br/bi;
1364 div = (br * ratio) + bi;
1365 tr = (ar * ratio) + ai;
1366 ti = (ai * ratio) - ar;
1367 tr = tr / div;
1368 ti = ti / div; */
1379 }
1380 else
1381 {
1382 /* In the FALSE branch, we compute
1383 ratio = d/c;
1384 divisor = (d * ratio) + c;
1385 tr = (b * ratio) + a;
1386 ti = b - (a * ratio);
1387 tr = tr / div;
1388 ti = ti / div; */
1400 }
1401 }
1406 }
1410 }
1414 {
1420 {
1426 /* It is possible that const_binop cannot handle the given
1427 code and return NULL_TREE */
1430 }
1433 }
1435 /* Shifts allow a scalar offset for a vector. */
1438 {
1444 {
1449 /* It is possible that const_binop cannot handle the given
1450 code and return NULL_TREE. */
1453 }
1456 }
1458 }
1460 /* Overload that adds a TYPE parameter to be able to dispatch
1461 to fold_relational_const. */
1463 tree
1465 {
1469 /* ??? Until we make the const_binop worker take the type of the
1470 result as argument put those cases that need it here. */
1472 {
1483 {
1499 {
1505 }
1508 }
1514 {
1539 {
1552 }
1555 }
1558 }
1563 /* Make sure type and arg0 have the same saturating flag. */
1568 }
1570 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1571 Return zero if computing the constants is not possible. */
1573 tree
1575 {
1576 /* Don't perform the operation, other than NEGATE and ABS, if
1577 flag_signaling_nans is on and the operand is a signaling NaN. */
1586 {
1587 CASE_CONVERT:
1594 /* If the source address is 0, and the source address space
1595 cannot have a valid object at 0, fold to dest type null. */
1606 {
1607 /* Can't call fold_negate_const directly here as that doesn't
1608 handle all cases and we might not be able to negate some
1609 constants. */
1614 }
1623 {
1627 }
1633 /* Perform BIT_NOT_EXPR on each element individually. */
1635 {
1637 tree elem;
1642 {
1648 }
1651 }
1673 {
1692 else
1696 {
1700 }
1703 }
1708 {
1722 {
1727 }
1730 {
1734 }
1737 }
1741 }
1744 }
1746 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1747 indicates which particular sizetype to create. */
1749 tree
1751 {
1753 }
1754 \f
1755 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1756 is a tree code. The type of the result is taken from the operands.
1757 Both must be equivalent integer types, ala int_binop_types_match_p.
1758 If the operands are constant, so is the result. */
1760 tree
1762 {
1771 /* Handle the special case of two integer constants faster. */
1773 {
1774 /* And some specific cases even faster than that. */
1776 {
1781 }
1783 {
1786 }
1788 {
1791 }
1793 /* Handle general case of two integer constants. For sizetype
1794 constant calculations we always want to know about overflow,
1795 even in the unsigned case. */
1797 }
1800 }
1802 /* Given two values, either both of sizetype or both of bitsizetype,
1803 compute the difference between the two values. Return the value
1804 in signed type corresponding to the type of the operands. */
1806 tree
1808 {
1810 tree ctype;
1815 /* If the type is already signed, just do the simple thing. */
1823 else
1826 /* If either operand is not a constant, do the conversions to the signed
1827 type and subtract. The hardware will do the right thing with any
1828 overflow in the subtraction. */
1834 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1835 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1836 overflow) and negate (which can't either). Special-case a result
1837 of zero while we're here. */
1843 else
1847 MINUS_EXPR,
1849 }
1850 \f
1851 /* A subroutine of fold_convert_const handling conversions of an
1852 INTEGER_CST to another integer type. */
1854 static tree
1856 {
1857 /* Given an integer constant, make new constant with new type,
1858 appropriately sign-extended or truncated. Use widest_int
1859 so that any extension is done according ARG1's type. */
1863 }
1865 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1866 to an integer type. */
1868 static tree
1870 {
1872 tree t;
1874 /* The following code implements the floating point to integer
1875 conversion rules required by the Java Language Specification,
1876 that IEEE NaNs are mapped to zero and values that overflow
1877 the target precision saturate, i.e. values greater than
1878 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1879 are mapped to INT_MIN. These semantics are allowed by the
1880 C and C++ standards that simply state that the behavior of
1881 FP-to-integer conversion is unspecified upon overflow. */
1883 wide_int val;
1884 REAL_VALUE_TYPE r;
1888 {
1895 }
1897 /* If R is NaN, return zero and show we have an overflow. */
1899 {
1902 }
1904 /* See if R is less than the lower bound or greater than the
1905 upper bound. */
1908 {
1912 {
1915 }
1916 }
1919 {
1922 {
1925 {
1928 }
1929 }
1930 }
1937 }
1939 /* A subroutine of fold_convert_const handling conversions of a
1940 FIXED_CST to an integer type. */
1942 static tree
1944 {
1945 tree t;
1949 /* Right shift FIXED_CST to temp by fbit. */
1953 {
1955 HOST_BITS_PER_DOUBLE_INT,
1958 /* Left shift temp to temp_trunc by fbit. */
1960 HOST_BITS_PER_DOUBLE_INT,
1962 }
1963 else
1964 {
1967 }
1969 /* If FIXED_CST is negative, we need to round the value toward 0.
1970 By checking if the fractional bits are not zero to add 1 to temp. */
1976 /* Given a fixed-point constant, make new constant with new type,
1977 appropriately sign-extended or truncated. */
1985 }
1987 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1988 to another floating point type. */
1990 static tree
1992 {
1993 REAL_VALUE_TYPE value;
1994 tree t;
1996 /* Don't perform the operation if flag_signaling_nans is on
1997 and the operand is a signaling NaN. */
2005 /* If converting an infinity or NAN to a representation that doesn't
2006 have one, set the overflow bit so that we can produce some kind of
2007 error message at the appropriate point if necessary. It's not the
2008 most user-friendly message, but it's better than nothing. */
2015 /* Regular overflow, conversion produced an infinity in a mode that
2016 can't represent them. */
2021 else
2024 }
2026 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2027 to a floating point type. */
2029 static tree
2031 {
2032 REAL_VALUE_TYPE value;
2033 tree t;
2041 }
2043 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2044 to another fixed-point type. */
2046 static tree
2048 {
2049 FIXED_VALUE_TYPE value;
2050 tree t;
2057 /* Propagate overflow flags. */
2061 }
2063 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2064 to a fixed-point type. */
2066 static tree
2068 {
2069 FIXED_VALUE_TYPE value;
2070 tree t;
2072 double_int di;
2079 else
2087 /* Propagate overflow flags. */
2091 }
2093 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2094 to a fixed-point type. */
2096 static tree
2098 {
2099 FIXED_VALUE_TYPE value;
2100 tree t;
2108 /* Propagate overflow flags. */
2112 }
2114 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2115 type TYPE. If no simplification can be done return NULL_TREE. */
2117 static tree
2119 {
2125 {
2132 }
2134 {
2141 }
2143 {
2150 }
2152 {
2155 {
2160 {
2166 }
2168 }
2169 }
2171 }
2173 /* Construct a vector of zero elements of vector type TYPE. */
2175 static tree
2177 {
2178 tree t;
2182 }
2184 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2186 bool
2188 {
2203 {
2218 }
2219 }
2221 /* Convert expression ARG to type TYPE. Used by the middle-end for
2222 simple conversions in preference to calling the front-end's convert. */
2224 tree
2226 {
2228 tree tem;
2239 {
2242 /* Handle conversions between pointers to different address spaces. */
2247 /* fall through */
2252 {
2256 }
2270 {
2274 }
2276 {
2280 }
2282 {
2286 }
2289 {
2307 }
2312 {
2316 }
2319 {
2333 }
2337 {
2346 integer_zero_node));
2348 {
2352 {
2358 }
2366 }
2370 }
2388 }
2389 fold_convert_exit:
2392 }
2393 \f
2394 /* Return false if expr can be assumed not to be an lvalue, true
2395 otherwise. */
2397 static bool
2399 {
2400 /* We only need to wrap lvalue tree codes. */
2402 {
2433 /* Assume the worst for front-end tree codes. */
2437 }
2440 }
2442 /* Return an expr equal to X but certainly not valid as an lvalue. */
2444 tree
2446 {
2447 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2448 us. */
2455 }
2457 /* When pedantic, return an expr equal to X but certainly not valid as a
2458 pedantic lvalue. Otherwise, return X. */
2460 static tree
2462 {
2464 }
2465 \f
2466 /* Given a tree comparison code, return the code that is the logical inverse.
2467 It is generally not safe to do this for floating-point comparisons, except
2468 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2469 ERROR_MARK in this case. */
2471 enum tree_code
2473 {
2479 {
2510 }
2511 }
2513 /* Similar, but return the comparison that results if the operands are
2514 swapped. This is safe for floating-point. */
2516 enum tree_code
2518 {
2520 {
2546 }
2547 }
2550 /* Convert a comparison tree code from an enum tree_code representation
2551 into a compcode bit-based encoding. This function is the inverse of
2552 compcode_to_comparison. */
2554 static enum comparison_code
2556 {
2558 {
2589 }
2590 }
2592 /* Convert a compcode bit-based encoding of a comparison operator back
2593 to GCC's enum tree_code representation. This function is the
2594 inverse of comparison_to_compcode. */
2596 static enum tree_code
2598 {
2600 {
2631 }
2632 }
2634 /* Return a tree for the comparison which is the combination of
2635 doing the AND or OR (depending on CODE) of the two operations LCODE
2636 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2637 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2638 if this makes the transformation invalid. */
2640 tree
2645 {
2652 {
2663 }
2666 {
2667 /* Eliminate unordered comparisons, as well as LTGT and ORD
2668 which are not used unless the mode has NaNs. */
2674 }
2676 {
2677 /* Check that the original operation and the optimized ones will trap
2678 under the same condition. */
2689 /* In a short-circuited boolean expression the LHS might be
2690 such that the RHS, if evaluated, will never trap. For
2691 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2692 if neither x nor y is NaN. (This is a mixed blessing: for
2693 example, the expression above will never trap, hence
2694 optimizing it to x < y would be invalid). */
2699 /* If the comparison was short-circuited, and only the RHS
2700 trapped, we may now generate a spurious trap. */
2705 /* If we changed the conditions that cause a trap, we lose. */
2708 }
2714 else
2715 {
2720 }
2721 }
2722 \f
2723 /* Return nonzero if two operands (typically of the same tree node)
2724 are necessarily equal. FLAGS modifies behavior as follows:
2726 If OEP_ONLY_CONST is set, only return nonzero for constants.
2727 This function tests whether the operands are indistinguishable;
2728 it does not test whether they are equal using C's == operation.
2729 The distinction is important for IEEE floating point, because
2730 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2731 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2733 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2734 even though it may hold multiple values during a function.
2735 This is because a GCC tree node guarantees that nothing else is
2736 executed between the evaluation of its "operands" (which may often
2737 be evaluated in arbitrary order). Hence if the operands themselves
2738 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2739 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2740 unset means assuming isochronic (or instantaneous) tree equivalence.
2741 Unless comparing arbitrary expression trees, such as from different
2742 statements, this flag can usually be left unset.
2744 If OEP_PURE_SAME is set, then pure functions with identical arguments
2745 are considered the same. It is used when the caller has other ways
2746 to ensure that global memory is unchanged in between.
2748 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2749 not values of expressions.
2751 If OEP_LEXICOGRAPHIC is set, then also handle expressions with side-effects
2752 such as MODIFY_EXPR, RETURN_EXPR, as well as STATEMENT_LISTs.
2754 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2755 any operand with side effect. This is unnecesarily conservative in the
2756 case we know that arg0 and arg1 are in disjoint code paths (such as in
2757 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2758 addresses with TREE_CONSTANT flag set so we know that &var == &var
2759 even if var is volatile. */
2761 int
2763 {
2764 /* When checking, verify at the outermost operand_equal_p call that
2765 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2766 hash value. */
2768 {
2770 {
2772 {
2779 }
2781 }
2782 else
2784 }
2786 /* If either is ERROR_MARK, they aren't equal. */
2792 /* Similar, if either does not have a type (like a released SSA name),
2793 they aren't equal. */
2797 /* We cannot consider pointers to different address space equal. */
2804 /* Check equality of integer constants before bailing out due to
2805 precision differences. */
2807 {
2808 /* Address of INTEGER_CST is not defined; check that we did not forget
2809 to drop the OEP_ADDRESS_OF flags. */
2812 }
2815 {
2816 /* If both types don't have the same signedness, then we can't consider
2817 them equal. We must check this before the STRIP_NOPS calls
2818 because they may change the signedness of the arguments. As pointers
2819 strictly don't have a signedness, require either two pointers or
2820 two non-pointers as well. */
2826 /* If both types don't have the same precision, then it is not safe
2827 to strip NOPs. */
2834 }
2835 #if 0
2836 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2837 sanity check once the issue is solved. */
2838 else
2839 /* Addresses of conversions and SSA_NAMEs (and many other things)
2840 are not defined. Check that we did not forget to drop the
2841 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2844 #endif
2846 /* In case both args are comparisons but with different comparison
2847 code, try to swap the comparison operands of one arg to produce
2848 a match and compare that variant. */
2852 {
2860 }
2863 {
2864 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2866 ;
2868 {
2869 /* If we are interested in comparing addresses ignore
2870 MEM_REF wrappings of the base that can appear just for
2871 TBAA reasons. */
2885 }
2886 else
2888 }
2890 /* When not checking adddresses, this is needed for conversions and for
2891 COMPONENT_REF. Might as well play it safe and always test this. */
2898 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2899 We don't care about side effects in that case because the SAVE_EXPR
2900 takes care of that for us. In all other cases, two expressions are
2901 equal if they have no side effects. If we have two identical
2902 expressions with side effects that should be treated the same due
2903 to the only side effects being identical SAVE_EXPR's, that will
2904 be detected in the recursive calls below.
2905 If we are taking an invariant address of two identical objects
2906 they are necessarily equal as well. */
2913 /* Next handle constant cases, those for which we can return 1 even
2914 if ONLY_CONST is set. */
2917 {
2931 {
2932 /* If we do not distinguish between signed and unsigned zero,
2933 consider them equal. */
2936 }
2940 {
2947 {
2951 }
2953 }
2957 flags)
2959 flags));
2970 flags | OEP_ADDRESS_OF
2973 /* In GIMPLE empty constructors are allowed in initializers of
2974 aggregates. */
2978 }
2983 /* Define macros to test an operand from arg0 and arg1 for equality and a
2984 variant that allows null and views null as being different from any
2985 non-null value. In the latter case, if either is null, the both
2986 must be; otherwise, do the normal comparison. */
2987 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2988 TREE_OPERAND (arg1, N), flags)
2990 #define OP_SAME_WITH_NULL(N) \
2991 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2992 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2995 {
2997 /* Two conversions are equal only if signedness and modes match. */
2999 {
3000 CASE_CONVERT:
3008 }
3018 /* For commutative ops, allow the other order. */
3026 /* If either of the pointer (or reference) expressions we are
3027 dereferencing contain a side effect, these cannot be equal,
3028 but their addresses can be. */
3035 {
3045 /* Require the same offset. */
3051 /* Fallthru. */
3059 {
3060 /* Require equal access sizes */
3066 flags)))
3068 /* Verify that access happens in similar types. */
3071 /* Verify that accesses are TBAA compatible. */
3080 /* Verify that alignment is compatible. */
3084 }
3087 /* TARGET_MEM_REF require equal extra operands. */
3098 /* Compare the array index by value if it is constant first as we
3099 may have different types but same value here. */
3105 /* Compare low bound and element size as with OEP_ADDRESS_OF
3106 we have to account for the offset of the ref. */
3111 array_ref_low_bound
3115 array_ref_element_size
3117 flags))));
3120 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3121 may be NULL when we're called to compare MEM_EXPRs. */
3136 }
3140 {
3142 /* Be sure we pass right ADDRESS_OF flag. */
3160 /* The multiplcation operands are commutative. */
3161 /* FALLTHRU */
3169 /* Otherwise take into account this is a commutative operation. */
3182 /* BIT_INSERT_EXPR has an implict operand as the type precision
3183 of op1. Need to check to make sure they are the same. */
3189 /* FALLTHRU */
3214 }
3218 {
3222 /* If not both CALL_EXPRs are either internal or normal function
3223 functions, then they are not equal. */
3226 {
3227 /* If the CALL_EXPRs call different internal functions, then they
3228 are not equal. */
3231 }
3232 else
3233 {
3234 /* If the CALL_EXPRs call different functions, then they are not
3235 equal. */
3237 flags))
3239 }
3241 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3242 {
3246 else
3250 }
3252 /* Now see if all the arguments are the same. */
3253 {
3264 /* If we get here and both argument lists are exhausted
3265 then the CALL_EXPRs are equal. */
3267 }
3270 }
3273 /* Consider __builtin_sqrt equal to sqrt. */
3281 {
3282 /* In GIMPLE constructors are used only to build vectors from
3283 elements. Individual elements in the constructor must be
3284 indexed in increasing order and form an initial sequence.
3286 We make no effort to compare constructors in generic.
3287 (see sem_variable::equals in ipa-icf which can do so for
3288 constants). */
3293 /* Be sure that vectors constructed have the same representation.
3294 We only tested element precision and modes to match.
3295 Vectors may be BLKmode and thus also check that the number of
3296 parts match. */
3309 {
3314 /* In GIMPLE the indexes can be either NULL or matching i.
3315 Double check this so we won't get false
3316 positives for GENERIC. */
3324 }
3326 }
3329 {
3330 /* Compare the STATEMENT_LISTs. */
3336 {
3337 /* The lists don't have the same number of statements. */
3343 OEP_LEXICOGRAPHIC))
3345 }
3346 }
3351 {
3358 }
3362 }
3364 #undef OP_SAME
3365 #undef OP_SAME_WITH_NULL
3366 }
3367 \f
3368 /* Similar to operand_equal_p, but strip nops first. */
3370 static bool
3372 {
3380 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3381 and see if the inner values are the same. This removes any
3382 signedness comparison, which doesn't matter here. */
3389 }
3390 \f
3391 /* See if ARG is an expression that is either a comparison or is performing
3392 arithmetic on comparisons. The comparisons must only be comparing
3393 two different values, which will be stored in *CVAL1 and *CVAL2; if
3394 they are nonzero it means that some operands have already been found.
3395 No variables may be used anywhere else in the expression except in the
3396 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3397 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3399 If this is true, return 1. Otherwise, return zero. */
3401 static int
3403 {
3407 /* We can handle some of the tcc_expression cases here. */
3417 {
3418 /* If we've already found a CVAL1 or CVAL2, this expression is
3419 two complex to handle. */
3425 }
3428 {
3451 /* First see if we can handle the first operand, then the second. For
3452 the second operand, we know *CVAL1 can't be zero. It must be that
3453 one side of the comparison is each of the values; test for the
3454 case where this isn't true by failing if the two operands
3455 are the same. */
3464 ;
3468 ;
3469 else
3473 ;
3477 ;
3478 else
3485 }
3486 }
3487 \f
3488 /* ARG is a tree that is known to contain just arithmetic operations and
3489 comparisons. Evaluate the operations in the tree substituting NEW0 for
3490 any occurrence of OLD0 as an operand of a comparison and likewise for
3491 NEW1 and OLD1. */
3493 static tree
3496 {
3501 /* We can handle some of the tcc_expression cases here. */
3509 {
3524 {
3543 }
3544 /* Fall through - ??? */
3547 {
3551 /* We need to check both for exact equality and tree equality. The
3552 former will be true if the operand has a side-effect. In that
3553 case, we know the operand occurred exactly once. */
3566 }
3570 }
3571 }
3572 \f
3573 /* Return a tree for the case when the result of an expression is RESULT
3574 converted to TYPE and OMITTED was previously an operand of the expression
3575 but is now not needed (e.g., we folded OMITTED * 0).
3577 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3578 the conversion of RESULT to TYPE. */
3580 tree
3582 {
3585 /* If the resulting operand is an empty statement, just return the omitted
3586 statement casted to void. */
3596 }
3598 /* Return a tree for the case when the result of an expression is RESULT
3599 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3600 of the expression but are now not needed.
3602 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3603 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3604 evaluated before OMITTED2. Otherwise, if neither has side effects,
3605 just do the conversion of RESULT to TYPE. */
3607 tree
3610 {
3619 }
3621 \f
3622 /* Return a simplified tree node for the truth-negation of ARG. This
3623 never alters ARG itself. We assume that ARG is an operation that
3624 returns a truth value (0 or 1).
3626 FIXME: one would think we would fold the result, but it causes
3627 problems with the dominator optimizer. */
3629 static tree
3631 {
3636 /* If this is a comparison, we can simply invert it, except for
3637 floating-point non-equality comparisons, in which case we just
3638 enclose a TRUTH_NOT_EXPR around what we have. */
3641 {
3644 && flag_trapping_math
3658 }
3661 {
3680 /* Here we can invert either operand. We invert the first operand
3681 unless the second operand is a TRUTH_NOT_EXPR in which case our
3682 result is the XOR of the first operand with the inside of the
3683 negation of the second operand. */
3688 else
3711 {
3718 /* A COND_EXPR may have a throw as one operand, which
3719 then has void type. Just leave void operands
3720 as they are. */
3726 }
3738 CASE_CONVERT:
3742 /* fall through */
3764 }
3765 }
3767 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3768 assume that ARG is an operation that returns a truth value (0 or 1
3769 for scalars, 0 or -1 for vectors). Return the folded expression if
3770 folding is successful. Otherwise, return NULL_TREE. */
3772 static tree
3774 {
3777 ? BIT_NOT_EXPR
3780 }
3782 /* Return a simplified tree node for the truth-negation of ARG. This
3783 never alters ARG itself. We assume that ARG is an operation that
3784 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3786 tree
3788 {
3794 ? BIT_NOT_EXPR
3797 }
3799 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3800 with code CODE. This optimization is unsafe. */
3801 static tree
3804 {
3808 /* (A / C) +- (B / C) -> (A +- B) / C. */
3818 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3823 {
3835 }
3838 }
3839 \f
3840 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3841 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3842 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3843 is the original memory reference used to preserve the alias set of
3844 the access. */
3846 static tree
3850 {
3853 /* Attempt not to lose the access path if possible. */
3855 {
3857 machine_mode nmode;
3859 tree noffset;
3869 && !reversep
3870 && !nreversep
3872 {
3875 }
3876 }
3885 {
3892 }
3907 }
3909 /* Optimize a bit-field compare.
3911 There are two cases: First is a compare against a constant and the
3912 second is a comparison of two items where the fields are at the same
3913 bit position relative to the start of a chunk (byte, halfword, word)
3914 large enough to contain it. In these cases we can avoid the shift
3915 implicit in bitfield extractions.
3917 For constants, we emit a compare of the shifted constant with the
3918 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3919 compared. For two fields at the same position, we do the ANDs with the
3920 similar mask and compare the result of the ANDs.
3922 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3923 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3924 are the left and right operands of the comparison, respectively.
3926 If the optimization described above can be done, we return the resulting
3927 tree. Otherwise we return zero. */
3929 static tree
3932 {
3935 tree unsigned_type;
3942 tree mask;
3943 tree offset;
3945 /* Get all the information about the extractions being done. If the bit size
3946 if the same as the size of the underlying object, we aren't doing an
3947 extraction at all and so can do nothing. We also don't want to
3948 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3949 then will no longer be able to replace it. */
3958 else
3959 {
3960 /* If this is not a constant, we can only do something if bit positions,
3961 sizes, signedness and storage order are the same. */
3962 rinner
3970 }
3972 /* Honor the C++ memory model and mimic what RTL expansion does. */
3976 {
3980 }
3982 /* See if we can find a mode to refer to this field. We should be able to,
3983 but fail if we can't. */
3992 /* Set signed and unsigned types of the precision of this mode for the
3993 shifts below. */
3996 /* Compute the bit position and size for the new reference and our offset
3997 within it. If the new reference is the same size as the original, we
3998 won't optimize anything, so return zero. */
4008 /* Make the mask to be used against the extracted field. */
4015 /* If not comparing with constant, just rework the comparison
4016 and return. */
4020 unsigned_type,
4023 mask),
4026 unsigned_type,
4029 mask));
4031 /* Otherwise, we are handling the constant case. See if the constant is too
4032 big for the field. Warn and return a tree for 0 (false) if so. We do
4033 this not only for its own sake, but to avoid having to test for this
4034 error case below. If we didn't, we might generate wrong code.
4036 For unsigned fields, the constant shifted right by the field length should
4037 be all zero. For signed fields, the high-order bits should agree with
4038 the sign bit. */
4041 {
4043 {
4047 }
4048 }
4049 else
4050 {
4053 {
4057 }
4058 }
4060 /* Single-bit compares should always be against zero. */
4062 {
4065 }
4067 /* Make a new bitfield reference, shift the constant over the
4068 appropriate number of bits and mask it with the computed mask
4069 (in case this was a signed field). If we changed it, make a new one. */
4077 mask);
4082 }
4083 \f
4084 /* Subroutine for fold_truth_andor_1: decode a field reference.
4086 If EXP is a comparison reference, we return the innermost reference.
4088 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4089 set to the starting bit number.
4091 If the innermost field can be completely contained in a mode-sized
4092 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4094 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4095 otherwise it is not changed.
4097 *PUNSIGNEDP is set to the signedness of the field.
4099 *PREVERSEP is set to the storage order of the field.
4101 *PMASK is set to the mask used. This is either contained in a
4102 BIT_AND_EXPR or derived from the width of the field.
4104 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4106 Return 0 if this is not a component reference or is one that we can't
4107 do anything with. */
4109 static tree
4114 {
4119 tree unsigned_type;
4122 /* All the optimizations using this function assume integer fields.
4123 There are problems with FP fields since the type_for_size call
4124 below can fail for, e.g., XFmode. */
4128 /* We are interested in the bare arrangement of bits, so strip everything
4129 that doesn't affect the machine mode. However, record the type of the
4130 outermost expression if it may matter below. */
4137 {
4143 }
4150 /* Reject out-of-bound accesses (PR79731). */
4158 /* If the number of bits in the reference is the same as the bitsize of
4159 the outer type, then the outer type gives the signedness. Otherwise
4160 (in case of a small bitfield) the signedness is unchanged. */
4164 /* Compute the mask to access the bitfield. */
4173 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4181 }
4183 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4184 bit positions and MASK is SIGNED. */
4186 static int
4188 {
4192 /* If this function returns true when the type of the mask is
4193 UNSIGNED, then there will be errors. In particular see
4194 gcc.c-torture/execute/990326-1.c. There does not appear to be
4195 any documentation paper trail as to why this is so. But the pre
4196 wide-int worked with that restriction and it has been preserved
4197 here. */
4202 }
4204 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4205 represents the sign bit of EXP's type. If EXP represents a sign
4206 or zero extension, also test VAL against the unextended type.
4207 The return value is the (sub)expression whose sign bit is VAL,
4208 or NULL_TREE otherwise. */
4210 tree
4212 {
4214 tree t;
4216 /* Tree EXP must have an integral type. */
4221 /* Tree VAL must be an integer constant. */
4230 /* Handle extension from a narrower type. */
4236 }
4238 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4239 to be evaluated unconditionally. */
4241 static int
4243 {
4244 /* Strip any conversions that don't change the machine mode. */
4253 /* Don't regard global variables as simple. They may be
4254 allocated in ways unknown to the compiler (shared memory,
4255 #pragma weak, etc). */
4258 /* Weakrefs are not safe to be read, since they can be NULL.
4259 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4260 have DECL_WEAK flag set. */
4262 /* Loading a static variable is unduly expensive, but global
4263 registers aren't expensive. */
4265 }
4267 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4268 to be evaluated unconditionally.
4269 I addition to simple_operand_p, we assume that comparisons, conversions,
4270 and logic-not operations are simple, if their operands are simple, too. */
4272 static bool
4274 {
4294 }
4296 \f
4297 /* The following functions are subroutines to fold_range_test and allow it to
4298 try to change a logical combination of comparisons into a range test.
4300 For example, both
4301 X == 2 || X == 3 || X == 4 || X == 5
4302 and
4303 X >= 2 && X <= 5
4304 are converted to
4305 (unsigned) (X - 2) <= 3
4307 We describe each set of comparisons as being either inside or outside
4308 a range, using a variable named like IN_P, and then describe the
4309 range with a lower and upper bound. If one of the bounds is omitted,
4310 it represents either the highest or lowest value of the type.
4312 In the comments below, we represent a range by two numbers in brackets
4313 preceded by a "+" to designate being inside that range, or a "-" to
4314 designate being outside that range, so the condition can be inverted by
4315 flipping the prefix. An omitted bound is represented by a "-". For
4316 example, "- [-, 10]" means being outside the range starting at the lowest
4317 possible value and ending at 10, in other words, being greater than 10.
4318 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4319 always false.
4321 We set up things so that the missing bounds are handled in a consistent
4322 manner so neither a missing bound nor "true" and "false" need to be
4323 handled using a special case. */
4325 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4326 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4327 and UPPER1_P are nonzero if the respective argument is an upper bound
4328 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4329 must be specified for a comparison. ARG1 will be converted to ARG0's
4330 type if both are specified. */
4332 static tree
4335 {
4336 tree tem;
4340 /* If neither arg represents infinity, do the normal operation.
4341 Else, if not a comparison, return infinity. Else handle the special
4342 comparison rules. Note that most of the cases below won't occur, but
4343 are handled for consistency. */
4346 {
4351 }
4356 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4357 for neither. In real maths, we cannot assume open ended ranges are
4358 the same. But, this is computer arithmetic, where numbers are finite.
4359 We can therefore make the transformation of any unbounded range with
4360 the value Z, Z being greater than any representable number. This permits
4361 us to treat unbounded ranges as equal. */
4365 {
4386 }
4389 }
4390 \f
4391 /* Helper routine for make_range. Perform one step for it, return
4392 new expression if the loop should continue or NULL_TREE if it should
4393 stop. */
4395 tree
4399 {
4405 {
4407 /* We can only do something if the range is testing for zero. */
4416 /* We can only do something if the range is testing for zero
4417 and if the second operand is an integer constant. Note that
4418 saying something is "in" the range we make is done by
4419 complementing IN_P since it will set in the initial case of
4420 being not equal to zero; "out" is leaving it alone. */
4427 {
4448 }
4450 /* If this is an unsigned comparison, we also know that EXP is
4451 greater than or equal to zero. We base the range tests we make
4452 on that fact, so we record it here so we can parse existing
4453 range tests. We test arg0_type since often the return type
4454 of, e.g. EQ_EXPR, is boolean. */
4456 {
4460 NULL_TREE))
4465 /* If the high bound is missing, but we have a nonzero low
4466 bound, reverse the range so it goes from zero to the low bound
4467 minus 1. */
4469 {
4474 }
4475 }
4483 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4484 low and high are non-NULL, then normalize will DTRT. */
4487 {
4492 }
4494 /* (-x) IN [a,b] -> x in [-b, -a] */
4506 /* ~ X -> -X - 1 */
4515 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4516 move a constant to the other side. */
4521 /* If EXP is signed, any overflow in the computation is undefined,
4522 so we don't worry about it so long as our computations on
4523 the bounds don't overflow. For unsigned, overflow is defined
4524 and this is exactly the right thing. */
4536 normalize:
4537 /* Check for an unsigned range which has wrapped around the maximum
4538 value thus making n_high < n_low, and normalize it. */
4540 {
4546 /* If the range is of the form +/- [ x+1, x ], we won't
4547 be able to normalize it. But then, it represents the
4548 whole range or the empty set, so make it
4549 +/- [ -, - ]. */
4553 else
4555 }
4556 else
4564 CASE_CONVERT:
4582 /* If we're converting arg0 from an unsigned type, to exp,
4583 a signed type, we will be doing the comparison as unsigned.
4584 The tests above have already verified that LOW and HIGH
4585 are both positive.
4587 So we have to ensure that we will handle large unsigned
4588 values the same way that the current signed bounds treat
4589 negative values. */
4592 {
4593 tree high_positive;
4594 tree equiv_type;
4595 /* For fixed-point modes, we need to pass the saturating flag
4596 as the 2nd parameter. */
4598 equiv_type
4601 else
4602 equiv_type
4605 /* A range without an upper bound is, naturally, unbounded.
4606 Since convert would have cropped a very large value, use
4607 the max value for the destination type. */
4608 high_positive
4615 high_positive),
4618 /* If the low bound is specified, "and" the range with the
4619 range for which the original unsigned value will be
4620 positive. */
4622 {
4625 integer_zero_node),
4626 high_positive))
4630 }
4631 else
4632 {
4633 /* Otherwise, "or" the range with the range of the input
4634 that will be interpreted as negative. */
4637 integer_zero_node),
4638 high_positive))
4642 }
4643 }
4652 }
4653 }
4655 /* Given EXP, a logical expression, set the range it is testing into
4656 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4657 actually being tested. *PLOW and *PHIGH will be made of the same
4658 type as the returned expression. If EXP is not a comparison, we
4659 will most likely not be returning a useful value and range. Set
4660 *STRICT_OVERFLOW_P to true if the return value is only valid
4661 because signed overflow is undefined; otherwise, do not change
4662 *STRICT_OVERFLOW_P. */
4664 tree
4667 {
4675 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4676 and see if we can refine the range. Some of the cases below may not
4677 happen, but it doesn't seem worth worrying about this. We "continue"
4678 the outer loop when we've changed something; otherwise we "break"
4679 the switch, which will "break" the while. */
4685 {
4691 {
4699 }
4708 }
4710 /* If EXP is a constant, we can evaluate whether this is true or false. */
4712 {
4719 }
4723 }
4725 /* Returns TRUE if [LOW, HIGH] range check can be optimized to
4726 a bitwise check i.e. when
4727 LOW == 0xXX...X00...0
4728 HIGH == 0xXX...X11...1
4729 Return corresponding mask in MASK and stem in VALUE. */
4731 static bool
4734 {
4757 }
4758 \f
4759 /* Helper routine for build_range_check and match.pd. Return the type to
4760 perform the check or NULL if it shouldn't be optimized. */
4762 tree
4764 {
4765 /* First make sure that arithmetics in this type is valid, then make sure
4766 that it wraps around. */
4772 {
4775 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4776 for the type in question, as we rely on this here. */
4786 else
4788 }
4790 }
4792 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4793 type, TYPE, return an expression to test if EXP is in (or out of, depending
4794 on IN_P) the range. Return 0 if the test couldn't be created. */
4796 tree
4799 {
4802 /* Disable this optimization for function pointer expressions
4803 on targets that require function pointer canonicalization. */
4810 {
4816 }
4838 value);
4841 {
4843 {
4847 }
4849 }
4851 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4853 {
4857 {
4859 {
4862 etype
4864 else
4867 }
4870 }
4871 }
4873 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4874 This requires wrap-around arithmetics for the type of the expression. */
4894 }
4895 \f
4896 /* Return the predecessor of VAL in its type, handling the infinite case. */
4898 static tree
4900 {
4906 else
4909 }
4911 /* Return the successor of VAL in its type, handling the infinite case. */
4913 static tree
4915 {
4921 else
4924 }
4926 /* Given two ranges, see if we can merge them into one. Return 1 if we
4927 can, 0 if we can't. Set the output range into the specified parameters. */
4929 bool
4932 {
4936 tree tem;
4946 /* Make range 0 be the range that starts first, or ends last if they
4947 start at the same value. Swap them if it isn't. */
4950 || (lowequal
4953 {
4957 }
4959 /* Now flag two cases, whether the ranges are disjoint or whether the
4960 second range is totally subsumed in the first. Note that the tests
4961 below are simplified by the ones above. */
4967 /* We now have four cases, depending on whether we are including or
4968 excluding the two ranges. */
4970 {
4971 /* If they don't overlap, the result is false. If the second range
4972 is a subset it is the result. Otherwise, the range is from the start
4973 of the second to the end of the first. */
4978 else
4980 }
4983 {
4984 /* If they don't overlap, the result is the first range. If they are
4985 equal, the result is false. If the second range is a subset of the
4986 first, and the ranges begin at the same place, we go from just after
4987 the end of the second range to the end of the first. If the second
4988 range is not a subset of the first, or if it is a subset and both
4989 ranges end at the same place, the range starts at the start of the
4990 first range and ends just before the second range.
4991 Otherwise, we can't describe this as a single range. */
4997 {
5002 {
5003 /* We are in the weird situation where high0 > high1 but
5004 high1 has no successor. Punt. */
5006 }
5007 }
5009 {
5014 {
5015 /* low0 < low1 but low1 has no predecessor. Punt. */
5017 }
5018 }
5019 else
5021 }
5024 {
5025 /* If they don't overlap, the result is the second range. If the second
5026 is a subset of the first, the result is false. Otherwise,
5027 the range starts just after the first range and ends at the
5028 end of the second. */
5033 else
5034 {
5039 {
5040 /* high1 > high0 but high0 has no successor. Punt. */
5042 }
5043 }
5044 }
5046 else
5047 {
5048 /* The case where we are excluding both ranges. Here the complex case
5049 is if they don't overlap. In that case, the only time we have a
5050 range is if they are adjacent. If the second is a subset of the
5051 first, the result is the first. Otherwise, the range to exclude
5052 starts at the beginning of the first range and ends at the end of the
5053 second. */
5055 {
5060 else
5061 {
5062 /* Canonicalize - [min, x] into - [-, x]. */
5065 {
5070 /* FALLTHROUGH */
5083 }
5085 /* Canonicalize - [x, max] into - [x, -]. */
5088 {
5093 /* FALLTHROUGH */
5109 }
5111 /* The ranges might be also adjacent between the maximum and
5112 minimum values of the given type. For
5113 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
5114 return + [x + 1, y - 1]. */
5116 {
5123 }
5124 else
5126 }
5127 }
5130 else
5132 }
5136 }
5137 \f
5139 /* Subroutine of fold, looking inside expressions of the form
5140 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5141 of the COND_EXPR. This function is being used also to optimize
5142 A op B ? C : A, by reversing the comparison first.
5144 Return a folded expression whose code is not a COND_EXPR
5145 anymore, or NULL_TREE if no folding opportunity is found. */
5147 static tree
5150 {
5155 tree tem;
5160 /* If we have A op 0 ? A : -A, consider applying the following
5161 transformations:
5163 A == 0? A : -A same as -A
5164 A != 0? A : -A same as A
5165 A >= 0? A : -A same as abs (A)
5166 A > 0? A : -A same as abs (A)
5167 A <= 0? A : -A same as -abs (A)
5168 A < 0? A : -A same as -abs (A)
5170 None of these transformations work for modes with signed
5171 zeros. If A is +/-0, the first two transformations will
5172 change the sign of the result (from +0 to -0, or vice
5173 versa). The last four will fix the sign of the result,
5174 even though the original expressions could be positive or
5175 negative, depending on the sign of A.
5177 Note that all these transformations are correct if A is
5178 NaN, since the two alternatives (A and -A) are also NaNs. */
5185 /* In the case that A is of the form X-Y, '-A' (arg2) may
5186 have already been folded to Y-X, check for that. */
5194 {
5206 /* Fall through. */
5217 /* FALLTHRU */
5227 }
5229 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5230 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5231 both transformations are correct when A is NaN: A != 0
5232 is then true, and A == 0 is false. */
5236 {
5241 }
5243 /* Try some transformations of A op B ? A : B.
5245 A == B? A : B same as B
5246 A != B? A : B same as A
5247 A >= B? A : B same as max (A, B)
5248 A > B? A : B same as max (B, A)
5249 A <= B? A : B same as min (A, B)
5250 A < B? A : B same as min (B, A)
5252 As above, these transformations don't work in the presence
5253 of signed zeros. For example, if A and B are zeros of
5254 opposite sign, the first two transformations will change
5255 the sign of the result. In the last four, the original
5256 expressions give different results for (A=+0, B=-0) and
5257 (A=-0, B=+0), but the transformed expressions do not.
5259 The first two transformations are correct if either A or B
5260 is a NaN. In the first transformation, the condition will
5261 be false, and B will indeed be chosen. In the case of the
5262 second transformation, the condition A != B will be true,
5263 and A will be chosen.
5265 The conversions to max() and min() are not correct if B is
5266 a number and A is not. The conditions in the original
5267 expressions will be false, so all four give B. The min()
5268 and max() versions would give a NaN instead. */
5271 /* Avoid these transformations if the COND_EXPR may be used
5272 as an lvalue in the C++ front-end. PR c++/19199. */
5273 && (in_gimple_form
5279 {
5285 {
5294 /* In C++ a ?: expression can be an lvalue, so put the
5295 operand which will be used if they are equal first
5296 so that we can convert this back to the
5297 corresponding COND_EXPR. */
5299 {
5307 }
5314 {
5322 }
5335 }
5336 }
5339 }
5342 \f
5343 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5344 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5345 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5346 false) >= 2)
5347 #endif
5349 /* EXP is some logical combination of boolean tests. See if we can
5350 merge it into some range test. Return the new tree if so. */
5352 static tree
5355 {
5371 /* If this is an OR operation, invert both sides; we will invert
5372 again at the end. */
5376 /* If both expressions are the same, if we can merge the ranges, and we
5377 can build the range test, return it or it inverted. If one of the
5378 ranges is always true or always false, consider it to be the same
5379 expression as the other. */
5387 {
5391 }
5393 /* On machines where the branch cost is expensive, if this is a
5394 short-circuited branch and the underlying object on both sides
5395 is the same, make a non-short-circuit operation. */
5401 {
5402 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5403 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5404 which cases we can't do this. */
5412 {
5421 {
5424 WARN_STRICT_OVERFLOW_COMPARISON);
5428 }
5429 }
5430 }
5433 }
5434 \f
5435 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5436 bit value. Arrange things so the extra bits will be set to zero if and
5437 only if C is signed-extended to its full width. If MASK is nonzero,
5438 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5440 static tree
5442 {
5445 tree temp;
5450 /* We work by getting just the sign bit into the low-order bit, then
5451 into the high-order bit, then sign-extend. We then XOR that value
5452 with C. */
5455 /* We must use a signed type in order to get an arithmetic right shift.
5456 However, we must also avoid introducing accidental overflows, so that
5457 a subsequent call to integer_zerop will work. Hence we must
5458 do the type conversion here. At this point, the constant is either
5459 zero or one, and the conversion to a signed type can never overflow.
5460 We could get an overflow if this conversion is done anywhere else. */
5469 /* If necessary, convert the type back to match the type of C. */
5474 }
5475 \f
5476 /* For an expression that has the form
5477 (A && B) || ~B
5478 or
5479 (A || B) && ~B,
5480 we can drop one of the inner expressions and simplify to
5481 A || ~B
5482 or
5483 A && ~B
5484 LOC is the location of the resulting expression. OP is the inner
5485 logical operation; the left-hand side in the examples above, while CMPOP
5486 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5487 removing a condition that guards another, as in
5488 (A != NULL && A->...) || A == NULL
5489 which we must not transform. If RHS_ONLY is true, only eliminate the
5490 right-most operand of the inner logical operation. */
5492 static tree
5495 {
5513 {
5516 {
5519 }
5520 }
5522 {
5525 {
5528 }
5529 }
5544 }
5546 /* Find ways of folding logical expressions of LHS and RHS:
5547 Try to merge two comparisons to the same innermost item.
5548 Look for range tests like "ch >= '0' && ch <= '9'".
5549 Look for combinations of simple terms on machines with expensive branches
5550 and evaluate the RHS unconditionally.
5552 For example, if we have p->a == 2 && p->b == 4 and we can make an
5553 object large enough to span both A and B, we can do this with a comparison
5554 against the object ANDed with the a mask.
5556 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5557 operations to do this with one comparison.
5559 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5560 function and the one above.
5562 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5563 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5565 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5566 two operands.
5568 We return the simplified tree or 0 if no optimization is possible. */
5570 static tree
5573 {
5574 /* If this is the "or" of two comparisons, we can do something if
5575 the comparisons are NE_EXPR. If this is the "and", we can do something
5576 if the comparisons are EQ_EXPR. I.e.,
5577 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5579 WANTED_CODE is this operation code. For single bit fields, we can
5580 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5581 comparison for one-bit fields. */
5602 /* Start by getting the comparison codes. Fail if anything is volatile.
5603 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5604 it were surrounded with a NE_EXPR. */
5613 {
5617 }
5620 {
5624 }
5635 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5638 {
5641 {
5646 }
5649 {
5655 }
5656 }
5661 /* If the RHS can be evaluated unconditionally and its operands are
5662 simple, it wins to evaluate the RHS unconditionally on machines
5663 with expensive branches. In this case, this isn't a comparison
5664 that can be merged. */
5671 {
5672 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5683 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5693 }
5695 /* See if the comparisons can be merged. Then get all the parameters for
5696 each side. */
5721 /* It must be true that the inner operation on the lhs of each
5722 comparison must be the same if we are to be able to do anything.
5723 Then see if we have constants. If not, the same must be true for
5724 the rhs's. */
5733 {
5736 }
5741 else
5744 /* If either comparison code is not correct for our logical operation,
5745 fail. However, we can convert a one-bit comparison against zero into
5746 the opposite comparison against that bit being set in the field. */
5750 {
5752 {
5753 /* Make the left operand unsigned, since we are only interested
5754 in the value of one bit. Otherwise we are doing the wrong
5755 thing below. */
5758 }
5759 else
5761 }
5763 /* This is analogous to the code for l_const above. */
5765 {
5767 {
5770 }
5771 else
5773 }
5775 /* See if we can find a mode that contains both fields being compared on
5776 the left. If we can't, fail. Otherwise, update all constants and masks
5777 to be relative to a field of that size. */
5782 volatilep);
5792 {
5795 }
5803 {
5810 {
5814 }
5815 }
5817 {
5824 {
5828 }
5829 }
5831 /* If the right sides are not constant, do the same for it. Also,
5832 disallow this optimization if a size or signedness mismatch occurs
5833 between the left and right sides. */
5835 {
5838 /* Make sure the two fields on the right
5839 correspond to the left without being swapped. */
5847 volatilep);
5857 {
5860 }
5869 /* Make a mask that corresponds to both fields being compared.
5870 Do this for both items being compared. If the operands are the
5871 same size and the bits being compared are in the same position
5872 then we can do this by masking both and comparing the masked
5873 results. */
5877 {
5891 }
5893 /* There is still another way we can do something: If both pairs of
5894 fields being compared are adjacent, we may be able to make a wider
5895 field containing them both.
5897 Note that we still must mask the lhs/rhs expressions. Furthermore,
5898 the mask must be shifted to account for the shift done by
5899 make_bit_field_ref. */
5904 {
5905 tree type;
5921 /* Convert to the smaller type before masking out unwanted bits. */
5924 {
5926 {
5930 }
5932 {
5936 }
5937 }
5946 }
5949 }
5951 /* Handle the case of comparisons with constants. If there is something in
5952 common between the masks, those bits of the constants must be the same.
5953 If not, the condition is always false. Test for this to avoid generating
5954 incorrect code below. */
5959 {
5961 {
5964 }
5965 else
5966 {
5969 }
5970 }
5972 /* Construct the expression we will return. First get the component
5973 reference we will make. Unless the mask is all ones the width of
5974 that field, perform the mask operation. Then compare with the
5975 merged constant. */
5986 }
5987 \f
5988 /* T is an integer expression that is being multiplied, divided, or taken a
5989 modulus (CODE says which and what kind of divide or modulus) by a
5990 constant C. See if we can eliminate that operation by folding it with
5991 other operations already in T. WIDE_TYPE, if non-null, is a type that
5992 should be used for the computation if wider than our type.
5994 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5995 (X * 2) + (Y * 4). We must, however, be assured that either the original
5996 expression would not overflow or that overflow is undefined for the type
5997 in the language in question.
5999 If we return a non-null expression, it is an equivalent form of the
6000 original computation, but need not be in the original type.
6002 We set *STRICT_OVERFLOW_P to true if the return values depends on
6003 signed overflow being undefined. Otherwise we do not change
6004 *STRICT_OVERFLOW_P. */
6006 static tree
6009 {
6010 /* To avoid exponential search depth, refuse to allow recursion past
6011 three levels. Beyond that (1) it's highly unlikely that we'll find
6012 something interesting and (2) we've probably processed it before
6013 when we built the inner expression. */
6016 tree ret;
6021 depth++;
6023 depth--;
6026 }
6028 static tree
6031 {
6042 /* Don't deal with constants of zero here; they confuse the code below. */
6052 /* Note that we need not handle conditional operations here since fold
6053 already handles those cases. So just do arithmetic here. */
6055 {
6057 /* For a constant, we can always simplify if we are a multiply
6058 or (for divide and modulus) if it is a multiple of our constant. */
6061 {
6064 /* If the multiplication overflowed, we lost information on it.
6065 See PR68142 and PR69845. */
6069 }
6073 /* If op0 is an expression ... */
6079 /* ... and has wrapping overflow, and its type is smaller
6080 than ctype, then we cannot pass through as widening. */
6085 /* ... or this is a truncation (t is narrower than op0),
6086 then we cannot pass through this narrowing. */
6089 /* ... or signedness changes for division or modulus,
6090 then we cannot pass through this conversion. */
6094 /* ... or has undefined overflow while the converted to
6095 type has not, we cannot do the operation in the inner type
6096 as that would introduce undefined overflow. */
6102 /* Pass the constant down and see if we can make a simplification. If
6103 we can, replace this expression with the inner simplification for
6104 possible later conversion to our or some other type. */
6109 code == MULT_EXPR
6111 strict_overflow_p))))
6116 /* If widening the type changes it from signed to unsigned, then we
6117 must avoid building ABS_EXPR itself as unsigned. */
6119 {
6123 {
6126 }
6128 }
6129 /* If the constant is negative, we cannot simplify this. */
6132 /* FALLTHROUGH */
6134 /* For division and modulus, type can't be unsigned, as e.g.
6135 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6136 For signed types, even with wrapping overflow, this is fine. */
6145 /* If widening the type changes the signedness, then we can't perform
6146 this optimization as that changes the result. */
6150 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6156 {
6163 }
6167 /* If the second operand is constant, this is a multiplication
6168 or floor division, by a power of two, so we can treat it that
6169 way unless the multiplier or divisor overflows. Signed
6170 left-shift overflow is implementation-defined rather than
6171 undefined in C90, so do not convert signed left shift into
6172 multiplication. */
6175 /* const_binop may not detect overflow correctly,
6176 so check for it explicitly here. */
6180 size_one_node,
6181 op1)))
6185 ctype,
6187 t1),
6192 /* See if we can eliminate the operation on both sides. If we can, we
6193 can return a new PLUS or MINUS. If we can't, the only remaining
6194 cases where we can do anything are if the second operand is a
6195 constant. */
6202 /* If not multiplication, we can only do this if both operands
6203 are divisible by c. */
6206 {
6211 }
6213 /* If this was a subtraction, negate OP1 and set it to be an addition.
6214 This simplifies the logic below. */
6216 {
6218 /* If OP1 was not easily negatable, the constant may be OP0. */
6220 {
6223 }
6224 }
6229 /* If either OP1 or C are negative, this optimization is not safe for
6230 some of the division and remainder types while for others we need
6231 to change the code. */
6233 {
6241 }
6243 /* If it's a multiply or a division/modulus operation of a multiple
6244 of our constant, do the operation and verify it doesn't overflow. */
6247 {
6250 /* We allow the constant to overflow with wrapping semantics. */
6254 }
6255 else
6258 /* If we have an unsigned type, we cannot widen the operation since it
6259 will change the result if the original computation overflowed. */
6263 /* The last case is if we are a multiply. In that case, we can
6264 apply the distributive law to commute the multiply and addition
6265 if the multiplication of the constants doesn't overflow
6266 and overflow is defined. With undefined overflow
6267 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6273 op1);
6278 /* We have a special case here if we are doing something like
6279 (C * 8) % 4 since we know that's zero. */
6282 /* If the multiplication can overflow we cannot optimize this. */
6286 {
6289 }
6291 /* ... fall through ... */
6295 /* If we can extract our operation from the LHS, do so and return a
6296 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6297 do something only if the second operand is a constant. */
6313 /* If these are the same operation types, we can associate them
6314 assuming no overflow. */
6316 {
6331 }
6333 /* If these operations "cancel" each other, we have the main
6334 optimizations of this pass, which occur when either constant is a
6335 multiple of the other, in which case we replace this with either an
6336 operation or CODE or TCODE.
6338 If we have an unsigned type, we cannot do this since it will change
6339 the result if the original computation overflowed. */
6346 {
6348 {
6355 }
6357 {
6364 }
6365 }
6370 }
6373 }
6374 \f
6375 /* Return a node which has the indicated constant VALUE (either 0 or
6376 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6377 and is of the indicated TYPE. */
6379 tree
6381 {
6390 else
6392 }
6395 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6396 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6397 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6398 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6399 COND is the first argument to CODE; otherwise (as in the example
6400 given here), it is the second argument. TYPE is the type of the
6401 original expression. Return NULL_TREE if no simplification is
6402 possible. */
6404 static tree
6409 {
6419 {
6423 /* If this operand throws an expression, then it does not make
6424 sense to try to perform a logical or arithmetic operation
6425 involving it. */
6430 }
6433 {
6438 }
6439 else
6440 /* Detect the case of mixing vector and scalar types - bail out. */
6446 /* This transformation is only worthwhile if we don't have to wrap ARG
6447 in a SAVE_EXPR and the operation can be simplified without recursing
6448 on at least one of the branches once its pushed inside the COND_EXPR. */
6457 {
6461 else
6463 }
6465 {
6469 else
6471 }
6473 /* Check that we have simplified at least one of the branches. */
6478 }
6480 \f
6481 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6483 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6484 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6485 ADDEND is the same as X.
6487 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6488 and finite. The problematic cases are when X is zero, and its mode
6489 has signed zeros. In the case of rounding towards -infinity,
6490 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6491 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6493 bool
6495 {
6499 /* Don't allow the fold with -fsignaling-nans. */
6503 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6507 /* In a vector or complex, we would need to check the sign of all zeros. */
6511 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6515 /* The mode has signed zeros, and we have to honor their sign.
6516 In this situation, there is only one case we can return true for.
6517 X - 0 is the same as X unless rounding towards -infinity is
6518 supported. */
6520 }
6522 /* Subroutine of match.pd that optimizes comparisons of a division by
6523 a nonzero integer constant against an integer constant, i.e.
6524 X/C1 op C2.
6526 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6527 GE_EXPR or LE_EXPR. ARG01 and ARG1 must be a INTEGER_CST. */
6529 enum tree_code
6532 {
6537 /* We have to do this the hard way to detect unsigned overflow.
6538 prod = int_const_binop (MULT_EXPR, c1, c2); */
6544 {
6548 /* Likewise *hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6551 }
6553 {
6556 {
6575 }
6576 }
6577 else
6578 {
6579 /* A negative divisor reverses the relational operators. */
6584 {
6603 }
6604 }
6617 }
6620 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6621 equality/inequality test, then return a simplified form of the test
6622 using a sign testing. Otherwise return NULL. TYPE is the desired
6623 result type. */
6625 static tree
6628 tree result_type)
6629 {
6630 /* If this is testing a single bit, we can optimize the test. */
6634 {
6635 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6636 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6640 /* This is only a win if casting to a signed type is cheap,
6641 i.e. when arg00's type is not a partial mode. */
6643 {
6646 result_type,
6649 }
6650 }
6653 }
6655 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6656 equality/inequality test, then return a simplified form of
6657 the test using shifts and logical operations. Otherwise return
6658 NULL. TYPE is the desired result type. */
6660 tree
6663 {
6664 /* If this is testing a single bit, we can optimize the test. */
6668 {
6677 /* First, see if we can fold the single bit test into a sign-bit
6678 test. */
6680 result_type);
6684 /* Otherwise we have (A & C) != 0 where C is a single bit,
6685 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6686 Similarly for (A & C) == 0. */
6688 /* If INNER is a right shift of a constant and it plus BITNUM does
6689 not overflow, adjust BITNUM and INNER. */
6695 {
6698 }
6700 /* If we are going to be able to omit the AND below, we must do our
6701 operations as unsigned. If we must use the AND, we have a choice.
6702 Normally unsigned is faster, but for some machines signed is. */
6720 /* Put the AND last so it can combine with more things. */
6723 /* Make sure to return the proper type. */
6727 }
6729 }
6731 /* Test whether it is preferable two swap two operands, ARG0 and
6732 ARG1, for example because ARG0 is an integer constant and ARG1
6733 isn't. */
6735 bool
6737 {
6751 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6752 for commutative and comparison operators. Ensuring a canonical
6753 form allows the optimizers to find additional redundancies without
6754 having to explicitly check for both orderings. */
6760 /* Put SSA_NAMEs last. */
6766 /* Put variables last. */
6773 }
6776 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6777 means A >= Y && A != MAX, but in this case we know that
6778 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6780 static tree
6782 {
6789 else
6798 {
6801 }
6803 {
6806 }
6807 else
6814 {
6815 /* Convert the pointer types into integer before taking the difference. */
6819 }
6820 else
6827 }
6829 /* Fold a sum or difference of at least one multiplication.
6830 Returns the folded tree or NULL if no simplification could be made. */
6832 static tree
6835 {
6839 /* (A * C) +- (B * C) -> (A+-B) * C.
6840 (A * C) +- A -> A * (C+-1).
6841 We are most concerned about the case where C is a constant,
6842 but other combinations show up during loop reduction. Since
6843 it is not difficult, try all four possibilities. */
6846 {
6849 }
6851 {
6854 }
6855 else
6856 {
6857 /* We cannot generate constant 1 for fract. */
6862 }
6864 {
6867 }
6869 {
6871 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6872 the purpose of this canonicalization. */
6876 {
6879 }
6880 else
6882 }
6883 else
6884 {
6885 /* We cannot generate constant 1 for fract. */
6890 }
6893 /* Prefer factoring a common non-constant. */
6903 /* No identical multiplicands; see if we can find a common
6904 power-of-two factor in non-power-of-two multiplies. This
6905 can help in multi-dimensional array access. */
6908 {
6911 tree maybe_same;
6915 /* Move min of absolute values to int11. */
6917 {
6922 }
6923 else
6927 /* The remainder should not be a constant, otherwise we
6928 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6929 increased the number of multiplications necessary. */
6931 {
6939 }
6940 }
6947 /* We are neither factoring zero nor minus one. */
6955 /* Same may be zero and thus the operation 'code' may overflow. Likewise
6956 same may be minus one and thus the multiplication may overflow. Perform
6957 the operations in an unsigned type. */
6962 /* If the sum evaluated to a constant that is not -INF the multiplication
6963 cannot overflow. */
6972 }
6974 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6975 specified by EXPR into the buffer PTR of length LEN bytes.
6976 Return the number of bytes placed in the buffer, or zero
6977 upon failure. */
6979 static int
6981 {
6995 {
6997 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
6998 number of bytes. */
7002 {
7009 else
7011 }
7012 else
7017 }
7019 }
7022 /* Subroutine of native_encode_expr. Encode the FIXED_CST
7023 specified by EXPR into the buffer PTR of length LEN bytes.
7024 Return the number of bytes placed in the buffer, or zero
7025 upon failure. */
7027 static int
7029 {
7033 FIXED_VALUE_TYPE value;
7049 }
7052 /* Subroutine of native_encode_expr. Encode the REAL_CST
7053 specified by EXPR into the buffer PTR of length LEN bytes.
7054 Return the number of bytes placed in the buffer, or zero
7055 upon failure. */
7057 static int
7059 {
7065 /* There are always 32 bits in each long, no matter the size of
7066 the hosts long. We handle floating point representations with
7067 up to 192 bits. */
7081 {
7086 {
7093 else
7095 }
7096 else
7097 {
7100 {
7101 /* Reverse bytes within each long, or within the entire float
7102 if it's smaller than a long (for HFmode). */
7105 }
7106 }
7111 }
7113 }
7115 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7116 specified by EXPR into the buffer PTR of length LEN bytes.
7117 Return the number of bytes placed in the buffer, or zero
7118 upon failure. */
7120 static int
7122 {
7124 tree part;
7139 }
7142 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7143 specified by EXPR into the buffer PTR of length LEN bytes.
7144 Return the number of bytes placed in the buffer, or zero
7145 upon failure. */
7147 static int
7149 {
7159 {
7161 {
7164 }
7175 }
7177 }
7180 /* Subroutine of native_encode_expr. Encode the STRING_CST
7181 specified by EXPR into the buffer PTR of length LEN bytes.
7182 Return the number of bytes placed in the buffer, or zero
7183 upon failure. */
7185 static int
7187 {
7189 HOST_WIDE_INT total_bytes;
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 OFF is not -1 then start
7222 the encoding at byte offset OFF and encode at most LEN bytes.
7223 Return the number of bytes placed in the buffer, or zero upon failure. */
7225 int
7227 {
7228 /* We don't support starting at negative offset and -1 is special. */
7233 {
7254 }
7255 }
7258 /* Subroutine of native_interpret_expr. Interpret the contents of
7259 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7260 If the buffer cannot be interpreted, return NULL_TREE. */
7262 static tree
7264 {
7274 }
7277 /* Subroutine of native_interpret_expr. Interpret the contents of
7278 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7279 If the buffer cannot be interpreted, return NULL_TREE. */
7281 static tree
7283 {
7285 double_int result;
7286 FIXED_VALUE_TYPE fixed_value;
7296 }
7299 /* Subroutine of native_interpret_expr. Interpret the contents of
7300 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7301 If the buffer cannot be interpreted, return NULL_TREE. */
7303 static tree
7305 {
7309 /* There are always 32 bits in each long, no matter the size of
7310 the hosts long. We handle floating point representations with
7311 up to 192 bits. */
7312 REAL_VALUE_TYPE r;
7323 {
7324 /* Both OFFSET and BYTE index within a long;
7325 bitpos indexes the whole float. */
7328 {
7335 else
7337 }
7338 else
7339 {
7342 {
7343 /* Reverse bytes within each long, or within the entire float
7344 if it's smaller than a long (for HFmode). */
7347 }
7348 }
7352 }
7356 }
7359 /* Subroutine of native_interpret_expr. Interpret the contents of
7360 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7361 If the buffer cannot be interpreted, return NULL_TREE. */
7363 static tree
7365 {
7380 }
7383 /* Subroutine of native_interpret_expr. Interpret the contents of
7384 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7385 If the buffer cannot be interpreted, return NULL_TREE. */
7387 static tree
7389 {
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 }
7470 /* Return true iff a constant of type TYPE is accepted by
7471 native_encode_expr. */
7473 bool
7475 {
7477 {
7487 }
7488 }
7490 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7491 TYPE at compile-time. If we're unable to perform the conversion
7492 return NULL_TREE. */
7494 static tree
7496 {
7497 /* We support up to 512-bit values (for V8DFmode). */
7501 /* Check that the host and target are sane. */
7510 }
7512 /* Build an expression for the address of T. Folds away INDIRECT_REF
7513 to avoid confusing the gimplify process. */
7515 tree
7517 {
7518 /* The size of the object is not relevant when talking about its address. */
7523 {
7528 }
7538 {
7543 }
7544 else
7548 }
7550 /* Build an expression for the address of T. */
7552 tree
7554 {
7558 }
7560 /* Fold a unary expression of code CODE and type TYPE with operand
7561 OP0. Return the folded expression if folding is successful.
7562 Otherwise, return NULL_TREE. */
7564 tree
7566 {
7567 tree tem;
7568 tree arg0;
7576 {
7579 {
7580 /* Don't use STRIP_NOPS, because signedness of argument type
7581 matters. */
7583 }
7584 else
7585 {
7586 /* Strip any conversions that don't change the mode. This
7587 is safe for every expression, except for a comparison
7588 expression because its signedness is derived from its
7589 operands.
7591 Note that this is done as an internal manipulation within
7592 the constant folder, in order to find the simplest
7593 representation of the arguments so that their form can be
7594 studied. In any cases, the appropriate type conversions
7595 should be put back in the tree that will get out of the
7596 constant folder. */
7598 }
7601 {
7604 {
7608 }
7609 }
7610 }
7617 {
7624 {
7638 /* If this was a conversion, and all we did was to move into
7639 inside the COND_EXPR, bring it back out. But leave it if
7640 it is a conversion from integer to integer and the
7641 result precision is no wider than a word since such a
7642 conversion is cheap and may be optimized away by combine,
7643 while it couldn't if it were outside the COND_EXPR. Then return
7644 so we don't get into an infinite recursion loop taking the
7645 conversion out and then back in. */
7657 && (INTEGRAL_TYPE_P
7670 }
7671 }
7674 {
7680 CASE_CONVERT:
7684 {
7685 /* If we have (type) (a CMP b) and type is an integral type, return
7686 new expression involving the new type. Canonicalize
7687 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7688 non-integral type.
7689 Do not fold the result as that would not simplify further, also
7690 folding again results in recursions. */
7700 }
7702 /* Handle (T *)&A.B.C for A being of type T and B and C
7703 living at offset zero. This occurs frequently in
7704 C++ upcasting and then accessing the base. */
7708 {
7710 tree offset;
7711 machine_mode mode;
7713 tree base
7717 /* If the reference was to a (constant) zero offset, we can use
7718 the address of the base if it has the same base type
7719 as the result type and the pointer type is unqualified. */
7726 }
7730 /* Detect assigning a bitfield. */
7732 && DECL_BIT_FIELD
7734 {
7735 /* Don't leave an assignment inside a conversion
7736 unless assigning a bitfield. */
7738 /* First do the assignment, then return converted constant. */
7743 }
7745 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7746 constants (if x has signed type, the sign bit cannot be set
7747 in c). This folds extension into the BIT_AND_EXPR.
7748 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7749 very likely don't have maximal range for their precision and this
7750 transformation effectively doesn't preserve non-maximal ranges. */
7754 {
7765 <= HOST_BITS_PER_WIDE_INT
7767 {
7771 cst &= HOST_WIDE_INT_M1U
7775 && !flag_syntax_only
7778 {
7782 }
7783 }
7785 {
7790 }
7791 }
7793 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7794 cast (T1)X will fold away. We assume that this happens when X itself
7795 is a cast. */
7799 {
7803 return fold_build_pointer_plus_loc
7805 }
7807 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7808 of the same precision, and X is an integer type not narrower than
7809 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7815 {
7821 }
7823 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7824 type of X and Y (integer types only). */
7829 {
7830 /* Be careful not to introduce new overflows. */
7831 tree mult_type;
7834 else
7838 {
7845 }
7846 }
7852 {
7859 }
7870 /* Convert fabs((double)float) into (double)fabsf(float). */
7873 {
7879 targ0));
7880 }
7884 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7903 /* Note that the operand of this must be an int
7904 and its values must be 0 or 1.
7905 ("true" is a fixed value perhaps depending on the language,
7906 but we don't handle values other than 1 correctly yet.) */
7913 /* Fold *&X to X if X is an lvalue. */
7915 {
7922 }
7928 }
7931 /* If the operation was a conversion do _not_ mark a resulting constant
7932 with TREE_OVERFLOW if the original constant was not. These conversions
7933 have implementation defined behavior and retaining the TREE_OVERFLOW
7934 flag here would confuse later passes such as VRP. */
7935 tree
7938 {
7947 }
7949 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7950 operands OP0 and OP1. LOC is the location of the resulting expression.
7951 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7952 Return the folded expression if folding is successful. Otherwise,
7953 return NULL_TREE. */
7954 static tree
7957 {
7958 tree tem;
7960 /* We only do these simplifications if we are optimizing. */
7964 /* Check for things like (A || B) && (A || C). We can convert this
7965 to A || (B && C). Note that either operator can be any of the four
7966 truth and/or operations and the transformation will still be
7967 valid. Also note that we only care about order for the
7968 ANDIF and ORIF operators. If B contains side effects, this
7969 might change the truth-value of A. */
7976 {
7996 /* This case if tricky because we must either have commutative
7997 operators or else A10 must not have side-effects. */
8003 a01);
8004 }
8006 /* See if we can build a range comparison. */
8012 {
8016 }
8020 {
8024 }
8026 /* Check for the possibility of merging component references. If our
8027 lhs is another similar operation, try to merge its rhs with our
8028 rhs. Then try to merge our lhs and rhs. */
8042 {
8049 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
8050 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
8051 We don't want to pack more than two leafs to a non-IF AND/OR
8052 expression.
8053 If tree-code of left-hand operand isn't an AND/OR-IF code and not
8054 equal to IF-CODE, then we don't want to add right-hand operand.
8055 If the inner right-hand side of left-hand operand has
8056 side-effects, or isn't simple, then we can't add to it,
8057 as otherwise we might destroy if-sequence. */
8060 /* Needed for sequence points to handle trappings, and
8061 side-effects. */
8063 {
8065 arg1);
8067 tem);
8068 }
8069 /* Same as above but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
8070 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
8073 /* Needed for sequence points to handle trappings, and
8074 side-effects. */
8076 {
8081 }
8082 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
8083 into (A OR B).
8084 For sequence point consistancy, we need to check for trapping,
8085 and side-effects. */
8089 }
8092 }
8094 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8095 by changing CODE to reduce the magnitude of constants involved in
8096 ARG0 of the comparison.
8097 Returns a canonicalized comparison tree if a simplification was
8098 possible, otherwise returns NULL_TREE.
8099 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8100 valid if signed overflow is undefined. */
8102 static tree
8106 {
8111 /* Match A +- CST code arg1. We can change this only if overflow
8112 is undefined. */
8115 /* In principle pointers also have undefined overflow behavior,
8116 but that causes problems elsewhere. */
8123 /* Identify the constant in arg0 and its sign. */
8127 /* Overflowed constants and zero will cause problems. */
8132 /* See if we can reduce the magnitude of the constant in
8133 arg0 by changing the comparison code. */
8134 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8138 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8142 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8146 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8150 else
8154 /* Now build the constant reduced in magnitude. But not if that
8155 would produce one outside of its types range. */
8171 }
8173 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8174 overflow further. Try to decrease the magnitude of constants involved
8175 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8176 and put sole constants at the second argument position.
8177 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8179 static tree
8182 {
8183 tree t;
8188 /* Try canonicalization by simplifying arg0. */
8193 {
8197 }
8199 /* Try canonicalization by simplifying arg1 using the swapped
8200 comparison. */
8208 }
8210 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8211 space. This is used to avoid issuing overflow warnings for
8212 expressions like &p->x which can not wrap. */
8214 static bool
8216 {
8223 wide_int wi_offset;
8229 else
8245 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8246 array. */
8248 {
8249 HOST_WIDE_INT base_size;
8254 }
8257 }
8259 /* Return a positive integer when the symbol DECL is known to have
8260 a nonzero address, zero when it's known not to (e.g., it's a weak
8261 symbol), and a negative integer when the symbol is not yet in the
8262 symbol table and so whether or not its address is zero is unknown.
8263 For function local objects always return positive integer. */
8264 static int
8266 {
8271 /* Function local objects are never NULL. */
8279 }
8281 /* Subroutine of fold_binary. This routine performs all of the
8282 transformations that are common to the equality/inequality
8283 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8284 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8285 fold_binary should call fold_binary. Fold a comparison with
8286 tree code CODE and type TYPE with operands OP0 and OP1. Return
8287 the folded comparison or NULL_TREE. */
8289 static tree
8292 {
8302 /* For comparisons of pointers we can decompose it to a compile time
8303 comparison of the base objects and the offsets into the object.
8304 This requires at least one operand being an ADDR_EXPR or a
8305 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8311 {
8314 machine_mode mode;
8318 /* Get base and offset for the access. Strip ADDR_EXPR for
8319 get_inner_reference, but put it back by stripping INDIRECT_REF
8320 off the base object if possible. indirect_baseN will be true
8321 if baseN is not an address but refers to the object itself. */
8324 {
8325 base0
8331 else
8333 }
8335 {
8339 {
8340 base0
8346 else
8348 }
8351 else
8355 {
8361 {
8364 }
8365 }
8366 }
8370 {
8371 base1
8377 else
8379 }
8381 {
8385 {
8386 base1
8392 else
8394 }
8397 else
8401 {
8407 {
8410 }
8411 }
8412 }
8414 /* If we have equivalent bases we might be able to simplify. */
8418 {
8419 /* We can fold this expression to a constant if the non-constant
8420 offset parts are equal. */
8424 {
8430 "occur when comparing P +- C1 with "
8432 WARN_STRICT_OVERFLOW_CONDITIONAL);
8435 {
8449 }
8450 }
8451 /* We can simplify the comparison to a comparison of the variable
8452 offset parts if the constant offset parts are equal.
8453 Be careful to use signed sizetype here because otherwise we
8454 mess with array offsets in the wrong way. This is possible
8455 because pointer arithmetic is restricted to retain within an
8456 object and overflow on pointer differences is undefined as of
8457 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8459 {
8460 /* By converting to signed sizetype we cover middle-end pointer
8461 arithmetic which operates on unsigned pointer types of size
8462 type size and ARRAY_REF offsets which are properly sign or
8463 zero extended from their type in case it is narrower than
8464 sizetype. */
8467 else
8471 else
8478 "occur when comparing P +- C1 with "
8480 WARN_STRICT_OVERFLOW_COMPARISON);
8483 }
8484 }
8485 /* For equal offsets we can simplify to a comparison of the
8486 base addresses. */
8488 && (indirect_base0
8490 && (indirect_base1
8495 {
8501 }
8502 /* Comparison between an ordinary (non-weak) symbol and a null
8503 pointer can be eliminated since such symbols must have a non
8504 null address. In C, relational expressions between pointers
8505 to objects and null pointers are undefined. The results
8506 below follow the C++ rules with the additional property that
8507 every object pointer compares greater than a null pointer.
8508 */
8511 /* Avoid folding references to struct members at offset 0 to
8512 prevent tests like '&ptr->firstmember == 0' from getting
8513 eliminated. When ptr is null, although the -> expression
8514 is strictly speaking invalid, GCC retains it as a matter
8515 of QoI. See PR c/44555. */
8518 && indirect_base0
8519 /* The caller guarantees that when one of the arguments is
8520 constant (i.e., null in this case) it is second. */
8522 {
8524 {
8535 }
8536 }
8537 }
8539 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8540 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8541 the resulting offset is smaller in absolute value than the
8542 original one and has the same sign. */
8551 {
8556 tree cst;
8558 "occur when combining constants around "
8561 /* Put the constant on the side where it doesn't overflow and is
8562 of lower absolute value and of same sign than before. */
8569 {
8572 variable1,
8576 }
8584 {
8590 variable2);
8591 }
8592 }
8598 /* If we are comparing an expression that just has comparisons
8599 of two integer values, arithmetic expressions of those comparisons,
8600 and constants, we can simplify it. There are only three cases
8601 to check: the two values can either be equal, the first can be
8602 greater, or the second can be greater. Fold the expression for
8603 those three values. Since each value must be 0 or 1, we have
8604 eight possibilities, each of which corresponds to the constant 0
8605 or 1 or one of the six possible comparisons.
8607 This handles common cases like (a > b) == 0 but also handles
8608 expressions like ((x > y) - (y > x)) > 0, which supposedly
8609 occur in macroized code. */
8612 {
8617 /* Don't handle degenerate cases here; they should already
8618 have been handled anyway. */
8627 {
8631 /* We can't just pass T to eval_subst in case cval1 or cval2
8632 was the same as ARG1. */
8634 tree high_result
8638 arg1);
8639 tree equal_result
8643 arg1);
8644 tree low_result
8648 arg1);
8650 /* All three of these results should be 0 or 1. Confirm they are.
8651 Then use those values to select the proper code to use. */
8656 {
8657 /* Make a 3-bit mask with the high-order bit being the
8658 value for `>', the next for '=', and the low for '<'. */
8662 {
8664 /* Always false. */
8685 /* Always true. */
8687 }
8690 {
8694 }
8696 }
8697 }
8698 }
8701 }
8704 /* Subroutine of fold_binary. Optimize complex multiplications of the
8705 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8706 argument EXPR represents the expression "z" of type TYPE. */
8708 static tree
8710 {
8715 {
8718 }
8720 {
8723 }
8724 else
8725 {
8729 }
8738 }
8741 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8742 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8744 static bool
8746 {
8750 {
8753 }
8755 {
8761 else
8763 }
8764 else
8770 }
8772 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8773 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8774 NULL_TREE otherwise. */
8776 static tree
8778 {
8795 {
8799 }
8802 {
8808 }
8809 else
8811 }
8813 /* Try to fold a pointer difference of type TYPE two address expressions of
8814 array references AREF0 and AREF1 using location LOC. Return a
8815 simplified expression for the difference or NULL_TREE. */
8817 static tree
8820 {
8825 /* If the bases are array references as well, recurse. If the bases
8826 are pointer indirections compute the difference of the pointers.
8827 If the bases are equal, we are set. */
8830 && (base_offset
8834 && (base_offset
8840 {
8846 base_offset,
8849 }
8851 }
8853 /* If the real or vector real constant CST of type TYPE has an exact
8854 inverse, return it, else return NULL. */
8856 tree
8858 {
8859 REAL_VALUE_TYPE r;
8861 machine_mode mode;
8865 {
8881 {
8886 }
8892 }
8893 }
8895 /* Mask out the tz least significant bits of X of type TYPE where
8896 tz is the number of trailing zeroes in Y. */
8897 static wide_int
8899 {
8904 }
8906 /* Return true when T is an address and is known to be nonzero.
8907 For floating point we further ensure that T is not denormal.
8908 Similar logic is present in nonzero_address in rtlanal.h.
8910 If the return value is based on the assumption that signed overflow
8911 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8912 change *STRICT_OVERFLOW_P. */
8914 static bool
8916 {
8920 /* Doing something useful for floating point would need more work. */
8926 {
8929 strict_overflow_p);
8935 strict_overflow_p);
8943 }
8946 {
8949 strict_overflow_p);
8957 strict_overflow_p);
8972 strict_overflow_p);
8976 strict_overflow_p);
8979 {
8991 }
8995 }
8997 }
8999 /* Return true when T is an address and is known to be nonzero.
9000 Handle warnings about undefined signed overflow. */
9002 bool
9004 {
9011 "determining that expression is always "
9013 WARN_STRICT_OVERFLOW_MISC);
9015 }
9017 /* Return true if T is known not to be equal to an integer W. */
9019 bool
9021 {
9023 value_range_type rtype;
9025 {
9034 {
9039 }
9044 /* If T has some known zero bits and W has any of those bits set,
9045 then T is known not to be equal to W. */
9053 }
9054 }
9056 /* Fold a binary expression of code CODE and type TYPE with operands
9057 OP0 and OP1. LOC is the location of the resulting expression.
9058 Return the folded expression if folding is successful. Otherwise,
9059 return NULL_TREE. */
9061 tree
9064 {
9079 /* Strip any conversions that don't change the mode. This is
9080 safe for every expression, except for a comparison expression
9081 because its signedness is derived from its operands. So, in
9082 the latter case, only strip conversions that don't change the
9083 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9084 preserved.
9086 Note that this is done as an internal manipulation within the
9087 constant folder, in order to find the simplest representation
9088 of the arguments so that their form can be studied. In any
9089 cases, the appropriate type conversions should be put back in
9090 the tree that will get out of the constant folder. */
9093 {
9096 }
9097 else
9098 {
9101 }
9103 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9104 constant but we can't do arithmetic on them. */
9106 {
9109 {
9113 }
9114 }
9116 /* If this is a commutative operation, and ARG0 is a constant, move it
9117 to ARG1 to reduce the number of tests below. */
9122 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9123 to ARG1 to reduce the number of tests below. */
9132 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9134 First check for cases where an arithmetic operation is applied to a
9135 compound, conditional, or comparison operation. Push the arithmetic
9136 operation inside the compound or conditional to see if any folding
9137 can then be done. Convert comparison to conditional for this purpose.
9138 The also optimizes non-constant cases that used to be done in
9139 expand_expr.
9141 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9142 one of the operands is a comparison and the other is a comparison, a
9143 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9144 code below would make the expression more complex. Change it to a
9145 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9146 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9159 {
9163 boolean_type_node,
9171 }
9175 {
9177 {
9182 tem);
9183 }
9185 {
9190 tem);
9191 }
9196 {
9202 }
9207 {
9213 }
9214 }
9217 {
9219 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9222 {
9228 }
9230 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9233 {
9234 tree base;
9235 HOST_WIDE_INT coffset;
9244 }
9249 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9255 arg1),
9257 arg0)));
9263 {
9264 /* X + (X / CST) * -CST is X % CST. */
9269 {
9278 cst0));
9279 }
9280 }
9282 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9283 one. Make sure the type is not saturating and has the signedness of
9284 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9285 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9292 {
9296 }
9299 {
9300 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9301 (plus (plus (mult) (mult)) (foo)) so that we can
9302 take advantage of the factoring cases below. */
9311 {
9317 else
9330 parg0),
9332 marg)),
9336 return
9342 parg1)));
9343 }
9344 }
9345 else
9346 {
9347 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9348 to __complex__ ( x, y ). This is not the same for SNaNs or
9349 if signed zeros are involved. */
9353 {
9360 {
9364 {
9370 }
9372 {
9378 }
9379 }
9380 }
9388 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9389 We associate floats only if the user has specified
9390 -fassociative-math. */
9394 {
9399 {
9400 tree tree0;
9403 }
9404 }
9405 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9406 We associate floats only if the user has specified
9407 -fassociative-math. */
9411 {
9416 {
9417 tree tree0;
9420 }
9421 }
9422 }
9424 bit_rotate:
9425 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9426 is a rotate of A by C1 bits. */
9427 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9428 is a rotate of A by B bits. */
9429 {
9431 tree rtype;
9440 /* Only create rotates in complete modes. Other cases are not
9441 expanded properly. */
9444 {
9458 {
9462 code0 == LSHIFT_EXPR
9466 }
9468 {
9476 element_precision
9480 return
9483 ? LROTATE_EXPR
9488 }
9490 {
9498 element_precision
9502 return fold_convert_loc
9505 ? LROTATE_EXPR
9509 }
9510 }
9511 }
9513 associate:
9514 /* In most languages, can't associate operations on floats through
9515 parentheses. Rather than remember where the parentheses were, we
9516 don't associate floats at all, unless the user has specified
9517 -fassociative-math.
9518 And, we need to make sure type is not saturating. */
9522 {
9528 /* Split both trees into variables, constants, and literals. Then
9529 associate each group together, the constants with literals,
9530 then the result with variables. This increases the chances of
9531 literals being recombined later and of generating relocatable
9532 expressions for the sum of a constant and literal. */
9540 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9544 /* With undefined overflow prefer doing association in a type
9545 which wraps on overflow, if that is one of the operand types. */
9548 {
9556 }
9558 /* With undefined overflow we can only associate constants with one
9559 variable, and constants whose association doesn't overflow. */
9562 {
9564 {
9565 /* ??? If split_tree would handle NEGATE_EXPR we could
9566 simply reject these cases and the allowed cases would
9567 be the var0/minus_var1 ones. */
9573 {
9576 }
9583 {
9586 }
9592 /* The only case we can still associate with two variables
9593 is if they cancel out. */
9597 }
9603 }
9605 /* Only do something if we found more than two objects. Otherwise,
9606 nothing has changed and we risk infinite recursion. */
9614 {
9626 {
9630 }
9632 {
9636 }
9638 /* Preserve the MINUS_EXPR if the negative part of the literal is
9639 greater than the positive part. Otherwise, the multiplicative
9640 folding code (i.e extract_muldiv) may be fooled in case
9641 unsigned constants are subtracted, like in the following
9642 example: ((X*2 + 4) - 8U)/2. */
9644 {
9648 /* But avoid ending up with only negated parts. */
9650 {
9654 }
9655 else
9656 {
9660 }
9661 }
9663 /* Don't introduce overflows through reassociation. */
9668 /* Eliminate lit0 and minus_lit0 to con0 and minus_con0. */
9675 /* Eliminate minus_con0. */
9677 {
9684 else
9687 }
9689 /* Eliminate minus_var0. */
9691 {
9695 else
9698 }
9700 return
9703 }
9704 }
9709 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9717 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9718 __complex__ ( x, -y ). This is not the same for SNaNs or if
9719 signed zeros are involved. */
9723 {
9730 {
9734 {
9736 arg1r ? arg1r
9741 }
9743 {
9747 arg1i ? arg1i
9750 }
9751 }
9752 }
9754 /* A - B -> A + (-B) if B is easily negatable. */
9758 /* Avoid this transformation if B is a positive REAL_CST. */
9766 /* Fold &a[i] - &a[j] to i-j. */
9771 {
9777 }
9780 && flag_unsafe_math_optimizations
9786 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9787 one. Make sure the type is not saturating and has the signedness of
9788 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9789 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9796 {
9800 }
9806 {
9807 /* Transform x * -C into -x * C if x is easily negatable. */
9822 {
9825 "occur when simplifying "
9827 WARN_STRICT_OVERFLOW_MISC);
9829 }
9831 /* Optimize z * conj(z) for integer complex numbers. */
9838 }
9839 else
9840 {
9841 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9842 This is not the same for NaNs or if signed zeros are
9843 involved. */
9849 {
9852 return
9858 return
9863 }
9865 /* Optimize z * conj(z) for floating point complex numbers.
9866 Guarded by flag_unsafe_math_optimizations as non-finite
9867 imaginary components don't produce scalar results. */
9876 }
9880 /* Canonicalize (X & C1) | C2. */
9884 {
9889 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9897 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9899 {
9902 }
9904 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9905 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9906 mode which allows further optimizations. */
9911 {
9915 {
9918 }
9919 }
9922 {
9927 }
9928 }
9930 /* See if this can be simplified into a rotate first. If that
9931 is unsuccessful continue in the association code. */
9935 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9943 /* See if this can be simplified into a rotate first. If that
9944 is unsuccessful continue in the association code. */
9948 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9953 {
9954 tree tem2;
9961 }
9962 /* Fold ~X & 1 as (X & 1) == 0. */
9966 {
9967 tree tem2;
9974 }
9975 /* Fold !X & 1 as X == 0. */
9978 {
9982 }
9984 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
9985 multiple of 1 << CST. */
9987 {
9994 }
9996 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
9997 bits from CST2. */
10001 {
10009 {
10010 /* Avoid the transform if arg1 is a mask of some
10011 mode which allows further optimizations. */
10018 }
10019 }
10021 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
10022 ((A & N) + B) & M -> (A + B) & M
10023 Similarly if (N & M) == 0,
10024 ((A | N) + B) & M -> (A + B) & M
10025 and for - instead of + (or unary - instead of +)
10026 and/or ^ instead of |.
10027 If B is constant and (B & M) == 0, fold into A & M. */
10029 {
10038 {
10041 wide_int cst0;
10043 /* Now we know that arg0 is (C + D) or (C - D) or
10044 -C and arg1 (M) is == (1LL << cst) - 1.
10045 Store C into PMOP[0] and D into PMOP[1]. */
10049 {
10052 }
10059 {
10069 {
10072 }
10075 /* If C or D is of the form (A & N) where
10076 (N & M) == M, or of the form (A | N) or
10077 (A ^ N) where (N & M) == 0, replace it with A. */
10081 /* If C or D is a N where (N & M) == 0, it can be
10082 omitted (assumed 0). */
10090 }
10092 /* Only build anything new if we optimized one or both arguments
10093 above. */
10097 {
10100 {
10101 /* Perform the operations in a type that has defined
10102 overflow behavior. */
10108 }
10113 {
10121 else
10123 }
10126 else
10129 /* TEM is now the new binary +, - or unary - replacement. */
10133 }
10134 }
10135 }
10137 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10140 {
10145 return
10147 }
10152 /* Don't touch a floating-point divide by zero unless the mode
10153 of the constant can represent infinity. */
10159 /* (-A) / (-B) -> A / B */
10171 /* Fall through */
10174 /* Simplify A / (B << N) where A and B are positive and B is
10175 a power of 2, to A >> (N + log2(B)). */
10180 {
10183 {
10191 WARN_STRICT_OVERFLOW_MISC);
10197 }
10198 }
10200 /* Fall through */
10208 /* Convert -A / -B to A / B when the type is signed and overflow is
10209 undefined. */
10213 {
10216 "when distributing negation across "
10218 WARN_STRICT_OVERFLOW_MISC);
10223 }
10227 {
10230 "when distributing negation across "
10232 WARN_STRICT_OVERFLOW_MISC);
10237 }
10239 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10240 operation, EXACT_DIV_EXPR.
10242 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10243 At one time others generated faster code, it's not clear if they do
10244 after the last round to changes to the DIV code in expmed.c. */
10255 {
10259 WARN_STRICT_OVERFLOW_MISC);
10261 }
10273 {
10277 WARN_STRICT_OVERFLOW_MISC);
10279 }
10287 /* Since negative shift count is not well-defined,
10288 don't try to compute it in the compiler. */
10294 /* If we have a rotate of a bit operation with the rotate count and
10295 the second operand of the bit operation both constant,
10296 permute the two operations. */
10302 {
10310 }
10312 /* Two consecutive rotates adding up to the some integer
10313 multiple of the precision of the type can be ignored. */
10328 /* Note that the operands of this must be ints
10329 and their values must be 0 or 1.
10330 ("true" is a fixed value perhaps depending on the language.) */
10331 /* If first arg is constant zero, return it. */
10334 /* FALLTHRU */
10336 /* If either arg is constant true, drop it. */
10340 /* Preserve sequence points. */
10343 /* If second arg is constant zero, result is zero, but first arg
10344 must be evaluated. */
10347 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10348 case will be handled here. */
10352 /* !X && X is always false. */
10356 /* X && !X is always false. */
10361 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10362 means A >= Y && A != MAX, but in this case we know that
10363 A < X <= MAX. */
10367 {
10375 }
10384 /* Note that the operands of this must be ints
10385 and their values must be 0 or true.
10386 ("true" is a fixed value perhaps depending on the language.) */
10387 /* If first arg is constant true, return it. */
10390 /* FALLTHRU */
10392 /* If either arg is constant zero, drop it. */
10396 /* Preserve sequence points. */
10399 /* If second arg is constant true, result is true, but we must
10400 evaluate first arg. */
10403 /* Likewise for first arg, but note this only occurs here for
10404 TRUTH_OR_EXPR. */
10408 /* !X || X is always true. */
10412 /* X || !X is always true. */
10417 /* (X && !Y) || (!X && Y) is X ^ Y */
10420 {
10437 }
10446 /* If the second arg is constant zero, drop it. */
10449 /* If the second arg is constant true, this is a logical inversion. */
10451 {
10454 }
10455 /* Identical arguments cancel to zero. */
10459 /* !X ^ X is always true. */
10464 /* X ^ !X is always true. */
10480 /* bool_var != 1 becomes !bool_var. */
10487 /* bool_var == 0 becomes !bool_var. */
10494 /* !exp != 0 becomes !exp */
10499 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10508 {
10514 }
10516 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10525 {
10531 }
10533 /* If this is an EQ or NE comparison with zero and ARG0 is
10534 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10535 two operations, but the latter can be done in one less insn
10536 on machines that have only two-operand insns or on which a
10537 constant cannot be the first operand. */
10540 {
10545 {
10552 arg1);
10553 }
10556 {
10563 arg1);
10564 }
10565 }
10567 /* If this is an NE or EQ comparison of zero against the result of a
10568 signed MOD operation whose second operand is a power of 2, make
10569 the MOD operation unsigned since it is simpler and equivalent. */
10577 {
10587 }
10589 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10590 C1 is a valid shift constant, and C2 is a power of two, i.e.
10591 a single bit. */
10595 == INTEGER_CST
10598 {
10603 /* Check for a valid shift count. */
10605 {
10609 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10610 can be rewritten as (X & (C2 << C1)) != 0. */
10612 {
10617 }
10618 /* Otherwise, for signed (arithmetic) shifts,
10619 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10620 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10624 /* Otherwise, of unsigned (logical) shifts,
10625 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10626 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10627 else
10631 arg000);
10632 }
10633 }
10635 /* If this is a comparison of a field, we may be able to simplify it. */
10638 /* Handle the constant case even without -O
10639 to make sure the warnings are given. */
10641 {
10645 }
10647 /* Optimize comparisons of strlen vs zero to a compare of the
10648 first character of the string vs zero. To wit,
10649 strlen(ptr) == 0 => *ptr == 0
10650 strlen(ptr) != 0 => *ptr != 0
10651 Other cases should reduce to one of these two (or a constant)
10652 due to the return value of strlen being unsigned. */
10655 {
10663 {
10668 }
10669 }
10671 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10672 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10676 {
10681 {
10683 {
10686 }
10689 }
10690 }
10692 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10693 (X & C) == 0 when C is a single bit. */
10698 {
10705 arg1));
10706 }
10708 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10709 constant C is a power of two, i.e. a single bit. */
10716 {
10720 }
10722 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10723 when is C is a power of two, i.e. a single bit. */
10730 {
10736 }
10740 {
10743 }
10745 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10748 {
10756 {
10762 }
10764 {
10770 }
10772 {
10778 }
10780 {
10786 }
10787 }
10791 {
10798 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10799 operand_equal_p guarantees no side-effects so we don't need
10800 to use omit_one_operand on Z. */
10804 arg10));
10808 arg11));
10812 arg10));
10816 arg11));
10818 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10821 {
10827 }
10828 }
10830 /* Attempt to simplify equality/inequality comparisons of complex
10831 values. Only lower the comparison if the result is known or
10832 can be simplified to a single scalar comparison. */
10837 {
10842 {
10845 }
10846 else
10847 {
10850 }
10853 {
10856 }
10857 else
10858 {
10861 }
10865 {
10867 {
10872 }
10873 else
10874 {
10879 }
10880 }
10884 {
10886 {
10891 }
10892 else
10893 {
10898 }
10899 }
10900 }
10912 /* Transform comparisons of the form X +- C CMP X. */
10919 {
10926 else
10929 /* (X - c) > X becomes false. */
10933 {
10937 "occur when assuming that (X - c) > X "
10939 WARN_STRICT_OVERFLOW_ALL);
10941 }
10943 /* Likewise (X + c) < X becomes false. */
10947 {
10951 "occur when assuming that "
10953 WARN_STRICT_OVERFLOW_ALL);
10955 }
10957 /* Convert (X - c) <= X to true. */
10962 {
10966 "occur when assuming that "
10968 WARN_STRICT_OVERFLOW_ALL);
10970 }
10972 /* Convert (X + c) >= X to true. */
10977 {
10981 "occur when assuming that "
10983 WARN_STRICT_OVERFLOW_ALL);
10985 }
10988 {
10989 /* Convert X + c > X and X - c < X to true for integers. */
10993 {
10996 "not occur when assuming that "
10998 WARN_STRICT_OVERFLOW_ALL);
11000 }
11005 {
11008 "not occur when assuming that "
11010 WARN_STRICT_OVERFLOW_ALL);
11012 }
11014 /* Convert X + c <= X and X - c >= X to false for integers. */
11018 {
11021 "not occur when assuming that "
11023 WARN_STRICT_OVERFLOW_ALL);
11025 }
11030 {
11033 "not occur when assuming that "
11035 WARN_STRICT_OVERFLOW_ALL);
11037 }
11038 }
11039 }
11041 /* If we are comparing an ABS_EXPR with a constant, we can
11042 convert all the cases into explicit comparisons, but they may
11043 well not be faster than doing the ABS and one comparison.
11044 But ABS (X) <= C is a range comparison, which becomes a subtraction
11045 and a comparison, and is probably faster. */
11059 /* Convert ABS_EXPR<x> >= 0 to true. */
11066 {
11069 "when simplifying comparison of "
11071 WARN_STRICT_OVERFLOW_CONDITIONAL);
11074 arg0);
11075 }
11077 /* Convert ABS_EXPR<x> < 0 to false. */
11082 {
11085 "when simplifying comparison of "
11087 WARN_STRICT_OVERFLOW_CONDITIONAL);
11090 arg0);
11091 }
11093 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11094 and similarly for >= into !=. */
11104 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11105 otherwise Y might be >= # of bits in X's type and thus e.g.
11106 (unsigned char) (1 << Y) for Y 15 might be 0.
11107 If the cast is widening, then 1 << Y should have unsigned type,
11108 otherwise if Y is number of bits in the signed shift type minus 1,
11109 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11110 31 might be 0xffffffff80000000. */
11121 {
11127 }
11139 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11140 {
11152 }
11157 /* When pedantic, a compound expression can be neither an lvalue
11158 nor an integer constant expression. */
11161 /* Don't let (0, 0) be null pointer constant. */
11167 /* An ASSERT_EXPR should never be passed to fold_binary. */
11173 }
11175 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11176 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11177 of GOTO_EXPR. */
11179 static tree
11181 {
11183 {
11190 /* fall through */
11194 }
11195 }
11197 /* Return whether the sub-tree ST contains a label which is accessible from
11198 outside the sub-tree. */
11200 static bool
11202 {
11203 return
11205 }
11207 /* Fold a ternary expression of code CODE and type TYPE with operands
11208 OP0, OP1, and OP2. Return the folded expression if folding is
11209 successful. Otherwise, return NULL_TREE. */
11211 tree
11214 {
11215 tree tem;
11222 /* If this is a commutative operation, and OP0 is a constant, move it
11223 to OP1 to reduce the number of tests below. */
11232 /* Strip any conversions that don't change the mode. This is safe
11233 for every expression, except for a comparison expression because
11234 its signedness is derived from its operands. So, in the latter
11235 case, only strip conversions that don't change the signedness.
11237 Note that this is done as an internal manipulation within the
11238 constant folder, in order to find the simplest representation of
11239 the arguments so that their form can be studied. In any cases,
11240 the appropriate type conversions should be put back in the tree
11241 that will get out of the constant folder. */
11243 {
11246 }
11249 {
11252 }
11255 {
11258 }
11261 {
11265 {
11271 }
11276 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11277 so all simple results must be passed through pedantic_non_lvalue. */
11279 {
11282 /* Only optimize constant conditions when the selected branch
11283 has the same type as the COND_EXPR. This avoids optimizing
11284 away "c ? x : throw", where the throw has a void type.
11285 Avoid throwing away that operand which contains label. */
11292 }
11294 {
11299 {
11304 {
11312 }
11316 }
11317 }
11319 /* If we have A op B ? A : C, we may be able to convert this to a
11320 simpler expression, depending on the operation and the values
11321 of B and C. Signed zeros prevent all of these transformations,
11322 for reasons given above each one.
11324 Also try swapping the arguments and inverting the conditional. */
11328 {
11332 }
11337 {
11341 {
11345 }
11346 }
11348 /* If the second operand is simpler than the third, swap them
11349 since that produces better jump optimization results. */
11352 {
11354 /* See if this can be inverted. If it can't, possibly because
11355 it was a floating-point inequality comparison, don't do
11356 anything. */
11360 }
11362 /* Convert A ? 1 : 0 to simply A. */
11367 /* If we try to convert OP0 to our type, the
11368 call to fold will try to move the conversion inside
11369 a COND, which will recurse. In that case, the COND_EXPR
11370 is probably the best choice, so leave it alone. */
11374 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11375 over COND_EXPR in cases such as floating point comparisons. */
11384 arg0)));
11386 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11391 {
11392 /* sign_bit_p looks through both zero and sign extensions,
11393 but for this optimization only sign extensions are
11394 usable. */
11397 {
11400 {
11403 }
11405 }
11406 /* sign_bit_p only checks ARG1 bits within A's precision.
11407 If <sign bit of A> has wider type than A, bits outside
11408 of A's precision in <sign bit of A> need to be checked.
11409 If they are all 0, this optimization needs to be done
11410 in unsigned A's type, if they are all 1 in signed A's type,
11411 otherwise this can't be done. */
11417 {
11419 tree tem_type;
11432 {
11435 }
11437 {
11440 }
11441 else
11443 }
11446 return
11452 arg1)));
11453 }
11455 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11456 already handled above. */
11461 {
11471 op1);
11472 }
11474 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11475 is probably obsolete because the first operand should be a
11476 truth value (that's why we have the two cases above), but let's
11477 leave it in until we can confirm this for all front-ends. */
11489 /* Disable the transformations below for vectors, since
11490 fold_binary_op_with_conditional_arg may undo them immediately,
11491 yielding an infinite loop. */
11495 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11504 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11509 {
11511 /* Only perform transformation if ARG0 is easily inverted. */
11515 ? BIT_IOR_EXPR
11518 op1);
11519 }
11521 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11526 {
11528 /* Only perform transformation if ARG0 is easily inverted. */
11534 op2);
11535 }
11537 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11549 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11550 of fold_ternary on them. */
11558 {
11568 {
11573 {
11581 }
11582 }
11583 }
11585 /* On constants we can use native encode/interpret to constant
11586 fold (nearly) all BIT_FIELD_REFs. */
11590 {
11593 /* Limit us to a reasonable amount of work. To relax the
11594 other limitations we need bit-shifting of the buffer
11595 and rounding up the size. */
11599 {
11601 unsigned HOST_WIDE_INT len
11606 {
11611 }
11612 }
11613 }
11618 /* For integers we can decompose the FMA if possible. */
11630 {
11646 {
11651 /* Make sure that the perm value is in an acceptable
11652 range. */
11661 else
11666 }
11669 {
11674 }
11679 {
11684 }
11690 {
11694 }
11699 /* Some targets are deficient and fail to expand a single
11700 argument permutation while still allowing an equivalent
11701 2-argument version. */
11705 {
11708 }
11711 {
11718 }
11722 }
11726 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11729 {
11735 wide_int tem2
11739 }
11744 {
11746 unsigned HOST_WIDE_INT elsize
11749 {
11753 else
11754 {
11760 }
11761 }
11762 }
11768 }
11770 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11771 of an array (or vector). */
11773 tree
11775 {
11780 {
11783 {
11784 /* Static constructors for variably sized objects makes no sense. */
11788 }
11789 }
11800 offset_int max_index;
11805 {
11806 /* Array constructor might explicitly set index, or specify a range,
11807 or leave index NULL meaning that it is next index after previous
11808 one. */
11810 {
11813 else
11814 {
11818 }
11819 }
11820 else
11821 {
11827 }
11829 /* Do we have match? */
11833 }
11835 }
11837 /* Perform constant folding and related simplification of EXPR.
11838 The related simplifications include x*1 => x, x*0 => 0, etc.,
11839 and application of the associative law.
11840 NOP_EXPR conversions may be removed freely (as long as we
11841 are careful not to change the type of the overall expression).
11842 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11843 but we can constant-fold them if they have constant operands. */
11845 #ifdef ENABLE_FOLD_CHECKING
11846 # define fold(x) fold_1 (x)
11848 static
11849 #endif
11850 tree
11852 {
11856 tree tem;
11859 /* Return right away if a constant. */
11863 /* CALL_EXPR-like objects with variable numbers of operands are
11864 treated specially. */
11866 {
11868 {
11871 }
11873 }
11876 {
11881 {
11899 }
11900 }
11903 {
11905 {
11912 {
11917 }
11920 }
11922 /* Return a VECTOR_CST if possible. */
11924 {
11930 tree val;
11936 }
11944 }
11946 #ifdef ENABLE_FOLD_CHECKING
11947 #undef fold
11954 /* When --enable-checking=fold, compute a digest of expr before
11955 and after actual fold call to see if fold did not accidentally
11956 change original expr. */
11958 tree
11960 {
11961 tree ret;
11981 }
11983 void
11985 {
11996 }
11998 static void
12000 {
12002 }
12004 static void
12007 {
12013 recursive_label:
12023 {
12024 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
12029 }
12037 {
12038 /* Allow these fields to be modified. */
12039 tree tmp;
12048 {
12051 }
12052 }
12063 {
12066 {
12081 }
12085 {
12098 }
12115 {
12121 }
12124 {
12126 {
12129 }
12131 }
12142 {
12145 }
12155 }
12156 }
12158 /* Helper function for outputting the checksum of a tree T. When
12159 debugging with gdb, you can "define mynext" to be "next" followed
12160 by "call debug_fold_checksum (op0)", then just trace down till the
12161 outputs differ. */
12163 DEBUG_FUNCTION void
12165 {
12180 }
12182 #endif
12184 /* Fold a unary tree expression with code CODE of type TYPE with an
12185 operand OP0. LOC is the location of the resulting expression.
12186 Return a folded expression if successful. Otherwise, return a tree
12187 expression with code CODE of type TYPE with an operand OP0. */
12189 tree
12192 {
12193 tree tem;
12194 #ifdef ENABLE_FOLD_CHECKING
12203 #endif
12209 #ifdef ENABLE_FOLD_CHECKING
12216 #endif
12218 }
12220 /* Fold a binary tree expression with code CODE of type TYPE with
12221 operands OP0 and OP1. LOC is the location of the resulting
12222 expression. Return a folded expression if successful. Otherwise,
12223 return a tree expression with code CODE of type TYPE with operands
12224 OP0 and OP1. */
12226 tree
12229 MEM_STAT_DECL)
12230 {
12231 tree tem;
12232 #ifdef ENABLE_FOLD_CHECKING
12249 #endif
12255 #ifdef ENABLE_FOLD_CHECKING
12270 #endif
12272 }
12274 /* Fold a ternary tree expression with code CODE of type TYPE with
12275 operands OP0, OP1, and OP2. Return a folded expression if
12276 successful. Otherwise, return a tree expression with code CODE of
12277 type TYPE with operands OP0, OP1, and OP2. */
12279 tree
12282 {
12283 tree tem;
12284 #ifdef ENABLE_FOLD_CHECKING
12308 #endif
12315 #ifdef ENABLE_FOLD_CHECKING
12338 #endif
12340 }
12342 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12343 arguments in ARGARRAY, and a null static chain.
12344 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12345 of type TYPE from the given operands as constructed by build_call_array. */
12347 tree
12350 {
12351 tree tem;
12352 #ifdef ENABLE_FOLD_CHECKING
12371 #endif
12377 #ifdef ENABLE_FOLD_CHECKING
12393 #endif
12395 }
12397 /* Perform constant folding and related simplification of initializer
12398 expression EXPR. These behave identically to "fold_buildN" but ignore
12399 potential run-time traps and exceptions that fold must preserve. */
12401 #define START_FOLD_INIT \
12402 int saved_signaling_nans = flag_signaling_nans;\
12403 int saved_trapping_math = flag_trapping_math;\
12404 int saved_rounding_math = flag_rounding_math;\
12405 int saved_trapv = flag_trapv;\
12406 int saved_folding_initializer = folding_initializer;\
12407 flag_signaling_nans = 0;\
12408 flag_trapping_math = 0;\
12409 flag_rounding_math = 0;\
12410 flag_trapv = 0;\
12411 folding_initializer = 1;
12413 #define END_FOLD_INIT \
12414 flag_signaling_nans = saved_signaling_nans;\
12415 flag_trapping_math = saved_trapping_math;\
12416 flag_rounding_math = saved_rounding_math;\
12417 flag_trapv = saved_trapv;\
12418 folding_initializer = saved_folding_initializer;
12420 tree
12423 {
12424 tree result;
12425 START_FOLD_INIT;
12429 END_FOLD_INIT;
12431 }
12433 tree
12436 {
12437 tree result;
12438 START_FOLD_INIT;
12442 END_FOLD_INIT;
12444 }
12446 tree
12449 {
12450 tree result;
12451 START_FOLD_INIT;
12455 END_FOLD_INIT;
12457 }
12459 #undef START_FOLD_INIT
12460 #undef END_FOLD_INIT
12462 /* Determine if first argument is a multiple of second argument. Return 0 if
12463 it is not, or we cannot easily determined it to be.
12465 An example of the sort of thing we care about (at this point; this routine
12466 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12467 fold cases do now) is discovering that
12469 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12471 is a multiple of
12473 SAVE_EXPR (J * 8)
12475 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12477 This code also handles discovering that
12479 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12481 is a multiple of 8 so we don't have to worry about dealing with a
12482 possible remainder.
12484 Note that we *look* inside a SAVE_EXPR only to determine how it was
12485 calculated; it is not safe for fold to do much of anything else with the
12486 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12487 at run time. For example, the latter example above *cannot* be implemented
12488 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12489 evaluation time of the original SAVE_EXPR is not necessarily the same at
12490 the time the new expression is evaluated. The only optimization of this
12491 sort that would be valid is changing
12493 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12495 divided by 8 to
12497 SAVE_EXPR (I) * SAVE_EXPR (J)
12499 (where the same SAVE_EXPR (J) is used in the original and the
12500 transformed version). */
12502 int
12504 {
12515 {
12517 /* Bitwise and provides a power of two multiple. If the mask is
12518 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12521 /* FALLTHRU */
12528 /* It is impossible to prove if op0 - op1 is multiple of bottom
12529 precisely, so be conservative here checking if both op0 and op1
12530 are multiple of bottom. Note we check the second operand first
12531 since it's usually simpler. */
12536 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12537 as op0 - 3 if the expression has unsigned type. For example,
12538 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12548 {
12550 /* const_binop may not detect overflow correctly,
12551 so check for it explicitly here. */
12555 size_one_node,
12556 op1)))
12559 }
12563 /* Can't handle conversions from non-integral or wider integral type. */
12569 /* fall through */
12586 SIGNED);
12592 {
12595 /* Check for special cases to see if top is defined as multiple
12596 of bottom:
12598 top = (X & ~(bottom - 1) ; bottom is power of 2
12600 or
12602 Y = X % bottom
12603 top = X - Y. */
12622 }
12624 /* fall through */
12628 }
12629 }
12631 #define tree_expr_nonnegative_warnv_p(X, Y) \
12634 #define RECURSE(X) \
12635 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12637 /* Return true if CODE or TYPE is known to be non-negative. */
12639 static bool
12641 {
12644 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12645 have a signed:1 type (where the value is -1 and 0). */
12648 }
12650 /* Return true if (CODE OP0) is known to be non-negative. If the return
12651 value is based on the assumption that signed overflow is undefined,
12652 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12653 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12655 bool
12658 {
12663 {
12665 /* We can't return 1 if flag_wrapv is set because
12666 ABS_EXPR<INT_MIN> = INT_MIN. */
12670 {
12673 }
12681 CASE_CONVERT:
12682 {
12687 {
12691 {
12695 }
12696 }
12698 {
12704 }
12705 }
12710 }
12712 /* We don't know sign of `t', so be conservative and return false. */
12714 }
12716 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12717 value is based on the assumption that signed overflow is undefined,
12718 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12719 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12721 bool
12725 {
12730 {
12736 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12737 both unsigned and at least 2 bits shorter than the result. */
12741 {
12746 {
12750 }
12751 }
12756 {
12757 /* x * x is always non-negative for floating point x
12758 or without overflow. */
12761 {
12766 }
12767 }
12769 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12770 both unsigned and their total bits is shorter than the result. */
12774 {
12793 {
12803 }
12804 }
12831 }
12833 /* We don't know sign of `t', so be conservative and return false. */
12835 }
12837 /* Return true if T is known to be non-negative. If the return
12838 value is based on the assumption that signed overflow is undefined,
12839 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12840 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12842 bool
12844 {
12849 {
12863 /* Limit the depth of recursion to avoid quadratic behavior.
12864 This is expected to catch almost all occurrences in practice.
12865 If this code misses important cases that unbounded recursion
12866 would not, passes that need this information could be revised
12867 to provide it through dataflow propagation. */
12875 }
12876 }
12878 /* Return true if T is known to be non-negative. If the return
12879 value is based on the assumption that signed overflow is undefined,
12880 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12881 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12883 bool
12886 {
12888 {
12889 CASE_CFN_ACOS:
12890 CASE_CFN_ACOSH:
12891 CASE_CFN_CABS:
12892 CASE_CFN_COSH:
12893 CASE_CFN_ERFC:
12894 CASE_CFN_EXP:
12895 CASE_CFN_EXP10:
12896 CASE_CFN_EXP2:
12897 CASE_CFN_FABS:
12898 CASE_CFN_FDIM:
12899 CASE_CFN_HYPOT:
12900 CASE_CFN_POW10:
12901 CASE_CFN_FFS:
12902 CASE_CFN_PARITY:
12903 CASE_CFN_POPCOUNT:
12904 CASE_CFN_CLZ:
12905 CASE_CFN_CLRSB:
12908 /* Always true. */
12911 CASE_CFN_SQRT:
12912 /* sqrt(-0.0) is -0.0. */
12917 CASE_CFN_ASINH:
12918 CASE_CFN_ATAN:
12919 CASE_CFN_ATANH:
12920 CASE_CFN_CBRT:
12921 CASE_CFN_CEIL:
12922 CASE_CFN_ERF:
12923 CASE_CFN_EXPM1:
12924 CASE_CFN_FLOOR:
12925 CASE_CFN_FMOD:
12926 CASE_CFN_FREXP:
12927 CASE_CFN_ICEIL:
12928 CASE_CFN_IFLOOR:
12929 CASE_CFN_IRINT:
12930 CASE_CFN_IROUND:
12931 CASE_CFN_LCEIL:
12932 CASE_CFN_LDEXP:
12933 CASE_CFN_LFLOOR:
12934 CASE_CFN_LLCEIL:
12935 CASE_CFN_LLFLOOR:
12936 CASE_CFN_LLRINT:
12937 CASE_CFN_LLROUND:
12938 CASE_CFN_LRINT:
12939 CASE_CFN_LROUND:
12940 CASE_CFN_MODF:
12941 CASE_CFN_NEARBYINT:
12942 CASE_CFN_RINT:
12943 CASE_CFN_ROUND:
12944 CASE_CFN_SCALB:
12945 CASE_CFN_SCALBLN:
12946 CASE_CFN_SCALBN:
12947 CASE_CFN_SIGNBIT:
12948 CASE_CFN_SIGNIFICAND:
12949 CASE_CFN_SINH:
12950 CASE_CFN_TANH:
12951 CASE_CFN_TRUNC:
12952 /* True if the 1st argument is nonnegative. */
12955 CASE_CFN_FMAX:
12956 /* True if the 1st OR 2nd arguments are nonnegative. */
12959 CASE_CFN_FMIN:
12960 /* True if the 1st AND 2nd arguments are nonnegative. */
12963 CASE_CFN_COPYSIGN:
12964 /* True if the 2nd argument is nonnegative. */
12967 CASE_CFN_POWI:
12968 /* True if the 1st argument is nonnegative or the second
12969 argument is an even integer. */
12975 CASE_CFN_POW:
12976 /* True if the 1st argument is nonnegative or the second
12977 argument is an even integer valued real. */
12979 {
12980 REAL_VALUE_TYPE c;
12981 HOST_WIDE_INT n;
12986 {
12987 REAL_VALUE_TYPE cint;
12991 }
12992 }
12997 }
12999 }
13001 /* Return true if T is known to be non-negative. If the return
13002 value is based on the assumption that signed overflow is undefined,
13003 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13004 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13006 static bool
13008 {
13014 {
13016 {
13020 /* If the initializer is non-void, then it's a normal expression
13021 that will be assigned to the slot. */
13025 /* Otherwise, the initializer sets the slot in some way. One common
13026 way is an assignment statement at the end of the initializer. */
13028 {
13036 else
13038 }
13044 }
13047 {
13053 arg0,
13054 arg1,
13056 }
13069 }
13070 }
13072 #undef RECURSE
13073 #undef tree_expr_nonnegative_warnv_p
13075 /* Return true if T is known to be non-negative. If the return
13076 value is based on the assumption that signed overflow is undefined,
13077 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13078 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13080 bool
13082 {
13089 {
13111 }
13114 {
13140 }
13141 }
13143 /* Return true if `t' is known to be non-negative. Handle warnings
13144 about undefined signed overflow. */
13146 bool
13148 {
13155 "determining that expression is always "
13157 WARN_STRICT_OVERFLOW_MISC);
13159 }
13162 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13163 For floating point we further ensure that T is not denormal.
13164 Similar logic is present in nonzero_address in rtlanal.h.
13166 If the return value is based on the assumption that signed overflow
13167 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13168 change *STRICT_OVERFLOW_P. */
13170 bool
13173 {
13175 {
13178 strict_overflow_p);
13181 {
13187 strict_overflow_p));
13188 }
13193 strict_overflow_p);
13197 }
13200 }
13202 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13203 For floating point we further ensure that T is not denormal.
13204 Similar logic is present in nonzero_address in rtlanal.h.
13206 If the return value is based on the assumption that signed overflow
13207 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13208 change *STRICT_OVERFLOW_P. */
13210 bool
13212 tree type,
13213 tree op0,
13215 {
13218 {
13222 {
13223 /* With the presence of negative values it is hard
13224 to say something. */
13231 /* One of operands must be positive and the other non-negative. */
13232 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13233 overflows, on a twos-complement machine the sum of two
13234 nonnegative numbers can never be zero. */
13236 strict_overflow_p)
13238 strict_overflow_p));
13239 }
13244 {
13246 strict_overflow_p)
13248 strict_overflow_p))
13249 {
13252 }
13253 }
13262 {
13265 }
13272 {
13276 /* When both operands are nonzero, then MAX must be too. */
13278 strict_overflow_p))
13281 /* MAX where operand 0 is positive is positive. */
13283 strict_overflow_p);
13284 }
13285 /* MAX where operand 1 is positive is positive. */
13290 {
13294 }
13299 strict_overflow_p)
13301 strict_overflow_p));
13305 }
13308 }
13310 /* Return true when T is an address and is known to be nonzero.
13311 For floating point we further ensure that T is not denormal.
13312 Similar logic is present in nonzero_address in rtlanal.h.
13314 If the return value is based on the assumption that signed overflow
13315 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13316 change *STRICT_OVERFLOW_P. */
13318 bool
13320 {
13323 {
13328 {
13340 /* For objects in symbol table check if we know they are non-zero.
13341 Don't do anything for variables and functions before symtab is built;
13342 it is quite possible that they will be declared weak later. */
13347 /* Constants are never weak. */
13352 }
13360 {
13364 }
13374 }
13376 }
13378 #define integer_valued_real_p(X) \
13381 #define RECURSE(X) \
13382 ((integer_valued_real_p) (X, depth + 1))
13384 /* Return true if the floating point result of (CODE OP0) has an
13385 integer value. We also allow +Inf, -Inf and NaN to be considered
13386 integer values. Return false for signaling NaN.
13388 DEPTH is the current nesting depth of the query. */
13390 bool
13392 {
13394 {
13401 CASE_CONVERT:
13402 {
13409 }
13413 }
13415 }
13417 /* Return true if the floating point result of (CODE OP0 OP1) has an
13418 integer value. We also allow +Inf, -Inf and NaN to be considered
13419 integer values. Return false for signaling NaN.
13421 DEPTH is the current nesting depth of the query. */
13423 bool
13425 {
13427 {
13437 }
13439 }
13441 /* Return true if the floating point result of calling FNDECL with arguments
13442 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13443 considered integer values. Return false for signaling NaN. If FNDECL
13444 takes fewer than 2 arguments, the remaining ARGn are null.
13446 DEPTH is the current nesting depth of the query. */
13448 bool
13450 {
13452 {
13453 CASE_CFN_CEIL:
13454 CASE_CFN_FLOOR:
13455 CASE_CFN_NEARBYINT:
13456 CASE_CFN_RINT:
13457 CASE_CFN_ROUND:
13458 CASE_CFN_TRUNC:
13461 CASE_CFN_FMIN:
13462 CASE_CFN_FMAX:
13467 }
13469 }
13471 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13472 has an integer value. We also allow +Inf, -Inf and NaN to be
13473 considered integer values. Return false for signaling NaN.
13475 DEPTH is the current nesting depth of the query. */
13477 bool
13479 {
13481 {
13489 /* Limit the depth of recursion to avoid quadratic behavior.
13490 This is expected to catch almost all occurrences in practice.
13491 If this code misses important cases that unbounded recursion
13492 would not, passes that need this information could be revised
13493 to provide it through dataflow propagation. */
13497 depth));
13501 }
13503 }
13505 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13506 has an integer value. We also allow +Inf, -Inf and NaN to be
13507 considered integer values. Return false for signaling NaN.
13509 DEPTH is the current nesting depth of the query. */
13511 static bool
13513 {
13515 {
13526 }
13528 }
13530 #undef RECURSE
13531 #undef integer_valued_real_p
13533 /* Return true if the floating point expression T has an integer value.
13534 We also allow +Inf, -Inf and NaN to be considered integer values.
13535 Return false for signaling NaN.
13537 DEPTH is the current nesting depth of the query. */
13539 bool
13541 {
13547 {
13563 }
13566 {
13572 {
13581 }
13585 }
13586 }
13588 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13589 attempt to fold the expression to a constant without modifying TYPE,
13590 OP0 or OP1.
13592 If the expression could be simplified to a constant, then return
13593 the constant. If the expression would not be simplified to a
13594 constant, then return NULL_TREE. */
13596 tree
13598 {
13601 }
13603 /* Given the components of a unary expression CODE, TYPE and OP0,
13604 attempt to fold the expression to a constant without modifying
13605 TYPE or OP0.
13607 If the expression could be simplified to a constant, then return
13608 the constant. If the expression would not be simplified to a
13609 constant, then return NULL_TREE. */
13611 tree
13613 {
13616 }
13618 /* If EXP represents referencing an element in a constant string
13619 (either via pointer arithmetic or array indexing), return the
13620 tree representing the value accessed, otherwise return NULL. */
13622 tree
13624 {
13628 {
13630 tree index;
13631 tree string;
13636 else
13637 {
13641 /* Optimize the special-case of a zero lower bound.
13643 We convert the low_bound to sizetype to avoid some problems
13644 with constant folding. (E.g. suppose the lower bound is 1,
13645 and its mode is QI. Without the conversion,l (ARRAY
13646 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13647 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13653 }
13655 scalar_int_mode char_mode;
13667 }
13669 }
13671 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13672 an integer constant, real, or fixed-point constant.
13674 TYPE is the type of the result. */
13676 static tree
13678 {
13682 {
13684 {
13691 }
13698 {
13699 FIXED_VALUE_TYPE f;
13704 /* Propagate overflow flags. */
13708 }
13712 }
13715 }
13717 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13718 an integer constant or real constant.
13720 TYPE is the type of the result. */
13722 tree
13724 {
13728 {
13730 {
13731 /* If the value is unsigned or non-negative, then the absolute value
13732 is the same as the ordinary value. */
13736 /* If the value is negative, then the absolute value is
13737 its negation. */
13738 else
13739 {
13744 }
13745 }
13751 else
13757 }
13760 }
13762 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13763 constant. TYPE is the type of the result. */
13765 static tree
13767 {
13771 }
13773 /* Given CODE, a relational operator, the target type, TYPE and two
13774 constant operands OP0 and OP1, return the result of the
13775 relational operation. If the result is not a compile time
13776 constant, then return NULL_TREE. */
13778 static tree
13780 {
13783 /* From here on, the only cases we handle are when the result is
13784 known to be a constant. */
13787 {
13791 /* Handle the cases where either operand is a NaN. */
13793 {
13795 {
13823 }
13826 }
13829 }
13832 {
13836 }
13838 /* Handle equality/inequality of complex constants. */
13840 {
13851 else
13853 }
13856 {
13858 {
13859 /* Have vector comparison with scalar boolean result. */
13863 {
13871 }
13873 }
13880 {
13892 }
13895 }
13897 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13899 To compute GT, swap the arguments and do LT.
13900 To compute GE, do LT and invert the result.
13901 To compute LE, swap the arguments, do LT and invert the result.
13902 To compute NE, do EQ and invert the result.
13904 Therefore, the code below must handle only EQ and LT. */
13907 {
13910 }
13912 /* Note that it is safe to invert for real values here because we
13913 have already handled the one case that it matters. */
13917 {
13920 }
13922 /* Compute a result for LT or EQ if args permit;
13923 Otherwise return T. */
13925 {
13928 else
13930 }
13931 else
13937 }
13939 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13940 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13941 itself. */
13943 tree
13945 {
13946 /* If the expression does not have side effects then we don't have to wrap
13947 it with a cleanup point expression. */
13951 /* If the expression is a return, check to see if the expression inside the
13952 return has no side effects or the right hand side of the modify expression
13953 inside the return. If either don't have side effects set we don't need to
13954 wrap the expression in a cleanup point expression. Note we don't check the
13955 left hand side of the modify because it should always be a return decl. */
13957 {
13964 }
13967 }
13969 /* Given a pointer value OP0 and a type TYPE, return a simplified version
13970 of an indirection through OP0, or NULL_TREE if no simplification is
13971 possible. */
13973 tree
13975 {
13977 tree subtype;
13986 {
13989 /* *&CONST_DECL -> to the value of the const decl. */
13992 /* *&p => p; make sure to handle *&"str"[cst] here. */
13994 {
13998 else
14000 }
14001 /* *(foo *)&fooarray => fooarray[0] */
14004 && (!in_gimple_form
14006 {
14016 }
14017 /* *(foo *)&complexfoo => __real__ complexfoo */
14021 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
14024 {
14028 }
14029 }
14033 {
14039 {
14040 tree op00type;
14044 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
14047 {
14049 unsigned HOST_WIDE_INT max_offset
14054 {
14061 }
14062 }
14063 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
14066 {
14070 }
14071 /* ((foo *)&fooarray)[1] => fooarray[1] */
14074 {
14081 offset_int remainder;
14084 {
14089 }
14090 }
14091 }
14092 }
14094 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14097 && (!in_gimple_form
14099 {
14100 tree type_domain;
14110 NULL_TREE);
14111 }
14114 }
14116 /* Builds an expression for an indirection through T, simplifying some
14117 cases. */
14119 tree
14121 {
14129 }
14131 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14133 tree
14135 {
14140 else
14142 }
14144 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14145 whose result is ignored. The type of the returned tree need not be
14146 the same as the original expression. */
14148 tree
14150 {
14156 {
14167 else
14173 {
14189 }
14194 }
14195 }
14197 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14199 tree
14201 {
14207 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14208 have to do anything. Only do this when we are not given a const,
14209 because in that case, this check is more expensive than just
14210 doing it. */
14212 {
14217 }
14219 /* If divisor is a power of two, simplify this to bit manipulation. */
14221 {
14223 {
14237 }
14238 else
14239 {
14240 tree t;
14246 }
14247 }
14248 else
14249 {
14254 }
14257 }
14259 /* Likewise, but round down. */
14261 tree
14263 {
14270 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14271 have to do anything. Only do this when we are not given a const,
14272 because in that case, this check is more expensive than just
14273 doing it. */
14275 {
14280 }
14282 /* If divisor is a power of two, simplify this to bit manipulation. */
14284 {
14285 tree t;
14289 }
14290 else
14291 {
14296 }
14299 }
14301 /* Returns the pointer to the base of the object addressed by EXP and
14302 extracts the information about the offset of the access, storing it
14303 to PBITPOS and POFFSET. */
14305 static tree
14308 {
14309 tree core;
14310 machine_mode mode;
14312 HOST_WIDE_INT bitsize;
14316 {
14321 }
14323 {
14329 {
14334 {
14337 }
14338 }
14339 }
14340 else
14341 {
14345 }
14348 }
14350 /* Returns true if addresses of E1 and E2 differ by a constant, false
14351 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14353 bool
14355 {
14369 {
14379 }
14381 {
14382 /* If only one of the offsets is non-constant, the difference cannot
14383 be a constant. */
14385 }
14386 else
14391 }
14393 /* Return OFF converted to a pointer offset type suitable as offset for
14394 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14395 tree
14397 {
14399 }
14401 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14402 tree
14404 {
14407 }
14409 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14410 tree
14412 {
14415 }
14417 /* Return a char pointer for a C string if it is a string constant
14418 or sum of string constant and integer constant. We only support
14419 string constants properly terminated with '\0' character.
14420 If STRLEN is a valid pointer, length (including terminating character)
14421 of returned string is stored to the argument. */
14425 {
14426 tree offset_node;
14437 {
14440 else
14442 }
14447 /* Support only properly null-terminated strings. */
14456 }
14458 #if CHECKING_P
14462 /* Helper functions for writing tests of folding trees. */
14464 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14466 static void
14468 tree constant)
14469 {
14471 }
14473 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14474 wrapping WRAPPED_EXPR. */
14476 static void
14478 tree wrapped_expr)
14479 {
14484 }
14486 /* Verify that various arithmetic binary operations are folded
14487 correctly. */
14489 static void
14491 {
14497 /* Addition. */
14498 /* 1 <-- (0 + 1) */
14500 one);
14502 one);
14504 /* (nonlvalue)x <-- (x + 0) */
14506 x);
14508 /* Subtraction. */
14509 /* 0 <-- (x - x) */
14511 zero);
14513 x);
14515 /* Multiplication. */
14516 /* 0 <-- (x * 0) */
14518 zero);
14520 /* (nonlvalue)x <-- (x * 1) */
14522 x);
14523 }
14525 /* Verify that various binary operations on vectors are folded
14526 correctly. */
14528 static void
14530 {
14536 /* Verify equality tests that return a scalar boolean result. */
14542 }
14544 /* Run all of the selftests within this file. */
14546 void
14548 {
14551 }