| blob | c649e547ead5997504b5b3addd22471532878e6f |
1 /* Fold a constant sub-tree into a single node for C-compiler
2 Copyright (C) 1987-2016 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. */
83 /* Nonzero if we are folding constants inside an initializer; zero
84 otherwise. */
87 /* The following constants represent a bit based encoding of GCC's
88 comparison operators. This encoding simplifies transformations
89 on relational comparison operators, such as AND and OR. */
107 };
144 /* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
145 Otherwise, return LOC. */
147 static location_t
149 {
152 }
154 /* Similar to protected_set_expr_location, but never modify x in place,
155 if location can and needs to be set, unshare it. */
159 {
165 {
168 }
170 }
171 \f
172 /* If ARG2 divides ARG1 with zero remainder, carries out the exact
173 division and returns the quotient. Otherwise returns
174 NULL_TREE. */
176 tree
178 {
179 widest_int quo;
186 }
187 \f
188 /* This is nonzero if we should defer warnings about undefined
189 overflow. This facility exists because these warnings are a
190 special case. The code to estimate loop iterations does not want
191 to issue any warnings, since it works with expressions which do not
192 occur in user code. Various bits of cleanup code call fold(), but
193 only use the result if it has certain characteristics (e.g., is a
194 constant); that code only wants to issue a warning if the result is
195 used. */
199 /* If a warning about undefined overflow is deferred, this is the
200 warning. Note that this may cause us to turn two warnings into
201 one, but that is fine since it is sufficient to only give one
202 warning per expression. */
206 /* If a warning about undefined overflow is deferred, this is the
207 level at which the warning should be emitted. */
211 /* Start deferring overflow warnings. We could use a stack here to
212 permit nested calls, but at present it is not necessary. */
214 void
216 {
218 }
220 /* Stop deferring overflow warnings. If there is a pending warning,
221 and ISSUE is true, then issue the warning if appropriate. STMT is
222 the statement with which the warning should be associated (used for
223 location information); STMT may be NULL. CODE is the level of the
224 warning--a warn_strict_overflow_code value. This function will use
225 the smaller of CODE and the deferred code when deciding whether to
226 issue the warning. CODE may be zero to mean to always use the
227 deferred code. */
229 void
231 {
233 location_t locus;
238 {
244 }
255 /* Use the smallest code level when deciding to issue the
256 warning. */
265 else
268 }
270 /* Stop deferring overflow warnings, ignoring any deferred
271 warnings. */
273 void
275 {
277 }
279 /* Whether we are deferring overflow warnings. */
281 bool
283 {
285 }
287 /* This is called when we fold something based on the fact that signed
288 overflow is undefined. */
290 void
292 {
294 {
297 {
300 }
301 }
304 }
305 \f
306 /* Return true if the built-in mathematical function specified by CODE
307 is odd, i.e. -f(x) == f(-x). */
309 bool
311 {
313 {
314 CASE_CFN_ASIN:
315 CASE_CFN_ASINH:
316 CASE_CFN_ATAN:
317 CASE_CFN_ATANH:
318 CASE_CFN_CASIN:
319 CASE_CFN_CASINH:
320 CASE_CFN_CATAN:
321 CASE_CFN_CATANH:
322 CASE_CFN_CBRT:
323 CASE_CFN_CPROJ:
324 CASE_CFN_CSIN:
325 CASE_CFN_CSINH:
326 CASE_CFN_CTAN:
327 CASE_CFN_CTANH:
328 CASE_CFN_ERF:
329 CASE_CFN_LLROUND:
330 CASE_CFN_LROUND:
331 CASE_CFN_ROUND:
332 CASE_CFN_SIN:
333 CASE_CFN_SINH:
334 CASE_CFN_TAN:
335 CASE_CFN_TANH:
336 CASE_CFN_TRUNC:
339 CASE_CFN_LLRINT:
340 CASE_CFN_LRINT:
341 CASE_CFN_NEARBYINT:
342 CASE_CFN_RINT:
347 }
349 }
351 /* Check whether we may negate an integer constant T without causing
352 overflow. */
354 bool
356 {
357 tree type;
366 }
368 /* Determine whether an expression T can be cheaply negated using
369 the function negate_expr without introducing undefined overflow. */
371 static bool
373 {
374 tree type;
383 {
388 /* Check that -CST will not overflow type. */
401 /* We want to canonicalize to positive real constants. Pretend
402 that only negative ones can be easily negated. */
410 {
421 }
436 /* -(A + B) -> (-B) - A. */
439 /* -(A + B) -> (-A) - B. */
443 /* We can't turn -(A-B) into B-A when we honor signed zeros. */
452 /* INT_MIN/n * n doesn't overflow while negating one operand it does
453 if n is a (negative) power of two. */
462 /* Fall through. */
477 /* In general we can't negate B in A / B, because if A is INT_MIN and
478 B is 1, we may turn this into INT_MIN / -1 which is undefined
479 and actually traps on some architectures. */
488 /* Negate -((double)float) as (double)(-float). */
490 {
494 }
498 /* Negate -f(x) as f(-x). */
504 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
506 {
510 }
515 }
517 }
519 /* Given T, an expression, return a folded tree for -T or NULL_TREE, if no
520 simplification is possible.
521 If negate_expr_p would return true for T, NULL_TREE will never be
522 returned. */
524 static tree
526 {
528 tree tem;
531 {
532 /* Convert - (~A) to A + 1. */
558 {
563 }
567 {
572 {
576 }
579 }
602 {
603 /* -(A + B) -> (-B) - A. */
605 {
609 }
611 /* -(A + B) -> (-A) - B. */
613 {
617 }
618 }
622 /* - (A - B) -> B - A */
633 /* Fall through. */
637 {
646 }
658 /* In general we can't negate B in A / B, because if A is INT_MIN and
659 B is 1, we may turn this into INT_MIN / -1 which is undefined
660 and actually traps on some architectures. */
672 /* Convert -((double)float) into (double)(-float). */
674 {
678 }
682 /* Negate -f(x) as f(-x). */
685 {
691 }
695 /* Optimize -((int)x >> 31) into (unsigned)x >> 31 for int. */
697 {
700 {
707 }
708 }
713 }
716 }
718 /* Like fold_negate_expr, but return a NEGATE_EXPR tree, if T can not be
719 negated in a simpler way. Also allow for T to be NULL_TREE, in which case
720 return NULL_TREE. */
722 static tree
724 {
726 location_t loc;
739 }
740 \f
741 /* Split a tree IN into a constant, literal and variable parts that could be
742 combined with CODE to make IN. "constant" means an expression with
743 TREE_CONSTANT but that isn't an actual constant. CODE must be a
744 commutative arithmetic operation. Store the constant part into *CONP,
745 the literal in *LITP and return the variable part. If a part isn't
746 present, set it to null. If the tree does not decompose in this way,
747 return the entire tree as the variable part and the other parts as null.
749 If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
750 case, we negate an operand that was subtracted. Except if it is a
751 literal for which we use *MINUS_LITP instead.
753 If NEGATE_P is true, we are negating all of IN, again except a literal
754 for which we use *MINUS_LITP instead. If a variable part is of pointer
755 type, it is negated after converting to TYPE. This prevents us from
756 generating illegal MINUS pointer expression. LOC is the location of
757 the converted variable part.
759 If IN is itself a literal or constant, return it as appropriate.
761 Note that we do not guarantee that any of the three values will be the
762 same type as IN, but they will have the same signedness and mode. */
764 static tree
767 {
774 /* Strip any conversions that don't change the machine mode or signedness. */
783 /* We can associate addition and subtraction together (even
784 though the C standard doesn't say so) for integers because
785 the value is not affected. For reals, the value might be
786 affected, so we can't. */
789 {
795 /* First see if either of the operands is a literal, then a constant. */
808 /* If we haven't dealt with either operand, this is not a case we can
809 decompose. Otherwise, VAR is either of the ones remaining, if any. */
814 else
817 /* Now do any needed negations. */
823 {
824 /* Convert to TYPE before negating. */
827 }
828 }
833 {
834 /* -X - 1 is folded to ~X, undo that here. Do _not_ do this
835 when IN is constant. */
838 }
839 else
843 {
850 {
851 /* Convert to TYPE before negating. */
854 }
855 }
858 }
860 /* Re-associate trees split by the above function. T1 and T2 are
861 either expressions to associate or null. Return the new
862 expression, if any. LOC is the location of the new expression. If
863 we build an operation, do it in TYPE and with CODE. */
865 static tree
867 {
873 /* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
874 try to fold this since we will have infinite recursion. But do
875 deal with any NEGATE_EXPRs. */
878 {
880 {
893 }
895 {
898 }
902 }
906 }
907 \f
908 /* Check whether TYPE1 and TYPE2 are equivalent integer types, suitable
909 for use in int_const_binop, size_binop and size_diffop. */
911 static bool
913 {
920 {
929 }
934 }
937 /* Combine two integer constants ARG1 and ARG2 under operation CODE
938 to produce a new constant. Return NULL_TREE if we don't know how
939 to evaluate CODE at compile-time. */
941 static tree
944 {
945 wide_int res;
946 tree t;
954 {
970 {
974 else
976 }
979 /* It's unclear from the C standard whether shifts can overflow.
980 The following code ignores overflow; perhaps a C standard
981 interpretation ruling is needed. */
983 else
990 {
994 else
996 }
1000 else
1079 }
1087 }
1089 tree
1091 {
1093 }
1095 /* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
1096 constant. We assume ARG1 and ARG2 have the same data type, or at least
1097 are the same kind of constant and the same machine mode. Return zero if
1098 combining the constants is not allowed in the current operating mode. */
1100 static tree
1102 {
1103 /* Sanity check for the recursive cases. */
1111 {
1117 }
1120 {
1121 machine_mode mode;
1122 REAL_VALUE_TYPE d1;
1123 REAL_VALUE_TYPE d2;
1124 REAL_VALUE_TYPE value;
1125 REAL_VALUE_TYPE result;
1129 /* The following codes are handled by real_arithmetic. */
1131 {
1142 }
1150 /* Don't perform operation if we honor signaling NaNs and
1151 either operand is a signaling NaN. */
1157 /* Don't perform operation if it would raise a division
1158 by zero exception. */
1164 /* If either operand is a NaN, just return it. Otherwise, set up
1165 for floating-point trap; we return an overflow. */
1167 {
1168 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1169 is off. */
1173 }
1175 {
1176 /* Make resulting NaN value to be qNaN when flag_signaling_nans
1177 is off. */
1181 }
1186 /* Don't constant fold this floating point operation if
1187 the result has overflowed and flag_trapping_math. */
1195 /* Don't constant fold this floating point operation if the
1196 result may dependent upon the run-time rounding mode and
1197 flag_rounding_math is set, or if GCC's software emulation
1198 is unable to accurately represent the result. */
1208 }
1211 {
1212 FIXED_VALUE_TYPE f1;
1213 FIXED_VALUE_TYPE f2;
1214 FIXED_VALUE_TYPE result;
1219 /* The following codes are handled by fixed_arithmetic. */
1221 {
1233 {
1240 }
1245 }
1252 /* Propagate overflow flags. */
1256 }
1259 {
1268 {
1279 mpc_mul);
1293 mpc_div);
1294 /* Fallthru. */
1300 {
1301 /* Keep this algorithm in sync with
1302 tree-complex.c:expand_complex_div_straight().
1304 Expand complex division to scalars, straightforward algorithm.
1305 a / b = ((ar*br + ai*bi)/t) + i((ai*br - ar*bi)/t)
1306 t = br*br + bi*bi
1307 */
1308 tree magsquared
1312 tree t1
1316 tree t2
1323 }
1324 else
1325 {
1326 /* Keep this algorithm in sync with
1327 tree-complex.c:expand_complex_div_wide().
1329 Expand complex division to scalars, modified algorithm to minimize
1330 overflow with wide input ranges. */
1336 {
1337 /* In the TRUE branch, we compute
1338 ratio = br/bi;
1339 div = (br * ratio) + bi;
1340 tr = (ar * ratio) + ai;
1341 ti = (ai * ratio) - ar;
1342 tr = tr / div;
1343 ti = ti / div; */
1354 }
1355 else
1356 {
1357 /* In the FALSE branch, we compute
1358 ratio = d/c;
1359 divisor = (d * ratio) + c;
1360 tr = (b * ratio) + a;
1361 ti = b - (a * ratio);
1362 tr = tr / div;
1363 ti = ti / div; */
1375 }
1376 }
1381 }
1385 }
1389 {
1395 {
1401 /* It is possible that const_binop cannot handle the given
1402 code and return NULL_TREE */
1405 }
1408 }
1410 /* Shifts allow a scalar offset for a vector. */
1413 {
1419 {
1424 /* It is possible that const_binop cannot handle the given
1425 code and return NULL_TREE. */
1428 }
1431 }
1433 }
1435 /* Overload that adds a TYPE parameter to be able to dispatch
1436 to fold_relational_const. */
1438 tree
1440 {
1444 /* ??? Until we make the const_binop worker take the type of the
1445 result as argument put those cases that need it here. */
1447 {
1458 {
1474 {
1480 }
1483 }
1489 {
1514 {
1527 }
1530 }
1533 }
1538 /* Make sure type and arg0 have the same saturating flag. */
1543 }
1545 /* Compute CODE ARG1 with resulting type TYPE with ARG1 being constant.
1546 Return zero if computing the constants is not possible. */
1548 tree
1550 {
1551 /* Don't perform the operation, other than NEGATE and ABS, if
1552 flag_signaling_nans is on and the operand is a signaling NaN. */
1561 {
1562 CASE_CONVERT:
1569 /* If the source address is 0, and the source address space
1570 cannot have a valid object at 0, fold to dest type null. */
1581 {
1582 /* Can't call fold_negate_const directly here as that doesn't
1583 handle all cases and we might not be able to negate some
1584 constants. */
1589 }
1598 {
1602 }
1608 /* Perform BIT_NOT_EXPR on each element individually. */
1610 {
1612 tree elem;
1617 {
1623 }
1626 }
1648 {
1667 else
1671 {
1675 }
1678 }
1683 {
1697 {
1702 }
1705 {
1709 }
1712 }
1716 }
1719 }
1721 /* Create a sizetype INT_CST node with NUMBER sign extended. KIND
1722 indicates which particular sizetype to create. */
1724 tree
1726 {
1728 }
1729 \f
1730 /* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
1731 is a tree code. The type of the result is taken from the operands.
1732 Both must be equivalent integer types, ala int_binop_types_match_p.
1733 If the operands are constant, so is the result. */
1735 tree
1737 {
1746 /* Handle the special case of two integer constants faster. */
1748 {
1749 /* And some specific cases even faster than that. */
1751 {
1756 }
1758 {
1761 }
1763 {
1766 }
1768 /* Handle general case of two integer constants. For sizetype
1769 constant calculations we always want to know about overflow,
1770 even in the unsigned case. */
1772 }
1775 }
1777 /* Given two values, either both of sizetype or both of bitsizetype,
1778 compute the difference between the two values. Return the value
1779 in signed type corresponding to the type of the operands. */
1781 tree
1783 {
1785 tree ctype;
1790 /* If the type is already signed, just do the simple thing. */
1798 else
1801 /* If either operand is not a constant, do the conversions to the signed
1802 type and subtract. The hardware will do the right thing with any
1803 overflow in the subtraction. */
1809 /* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
1810 Otherwise, subtract the other way, convert to CTYPE (we know that can't
1811 overflow) and negate (which can't either). Special-case a result
1812 of zero while we're here. */
1818 else
1822 MINUS_EXPR,
1824 }
1825 \f
1826 /* A subroutine of fold_convert_const handling conversions of an
1827 INTEGER_CST to another integer type. */
1829 static tree
1831 {
1832 /* Given an integer constant, make new constant with new type,
1833 appropriately sign-extended or truncated. Use widest_int
1834 so that any extension is done according ARG1's type. */
1838 }
1840 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1841 to an integer type. */
1843 static tree
1845 {
1847 tree t;
1849 /* The following code implements the floating point to integer
1850 conversion rules required by the Java Language Specification,
1851 that IEEE NaNs are mapped to zero and values that overflow
1852 the target precision saturate, i.e. values greater than
1853 INT_MAX are mapped to INT_MAX, and values less than INT_MIN
1854 are mapped to INT_MIN. These semantics are allowed by the
1855 C and C++ standards that simply state that the behavior of
1856 FP-to-integer conversion is unspecified upon overflow. */
1858 wide_int val;
1859 REAL_VALUE_TYPE r;
1863 {
1870 }
1872 /* If R is NaN, return zero and show we have an overflow. */
1874 {
1877 }
1879 /* See if R is less than the lower bound or greater than the
1880 upper bound. */
1883 {
1887 {
1890 }
1891 }
1894 {
1897 {
1900 {
1903 }
1904 }
1905 }
1912 }
1914 /* A subroutine of fold_convert_const handling conversions of a
1915 FIXED_CST to an integer type. */
1917 static tree
1919 {
1920 tree t;
1924 /* Right shift FIXED_CST to temp by fbit. */
1928 {
1930 HOST_BITS_PER_DOUBLE_INT,
1933 /* Left shift temp to temp_trunc by fbit. */
1935 HOST_BITS_PER_DOUBLE_INT,
1937 }
1938 else
1939 {
1942 }
1944 /* If FIXED_CST is negative, we need to round the value toward 0.
1945 By checking if the fractional bits are not zero to add 1 to temp. */
1951 /* Given a fixed-point constant, make new constant with new type,
1952 appropriately sign-extended or truncated. */
1960 }
1962 /* A subroutine of fold_convert_const handling conversions a REAL_CST
1963 to another floating point type. */
1965 static tree
1967 {
1968 REAL_VALUE_TYPE value;
1969 tree t;
1971 /* Don't perform the operation if flag_signaling_nans is on
1972 and the operand is a signaling NaN. */
1980 /* If converting an infinity or NAN to a representation that doesn't
1981 have one, set the overflow bit so that we can produce some kind of
1982 error message at the appropriate point if necessary. It's not the
1983 most user-friendly message, but it's better than nothing. */
1990 /* Regular overflow, conversion produced an infinity in a mode that
1991 can't represent them. */
1996 else
1999 }
2001 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2002 to a floating point type. */
2004 static tree
2006 {
2007 REAL_VALUE_TYPE value;
2008 tree t;
2015 }
2017 /* A subroutine of fold_convert_const handling conversions a FIXED_CST
2018 to another fixed-point type. */
2020 static tree
2022 {
2023 FIXED_VALUE_TYPE value;
2024 tree t;
2031 /* Propagate overflow flags. */
2035 }
2037 /* A subroutine of fold_convert_const handling conversions an INTEGER_CST
2038 to a fixed-point type. */
2040 static tree
2042 {
2043 FIXED_VALUE_TYPE value;
2044 tree t;
2046 double_int di;
2053 else
2061 /* Propagate overflow flags. */
2065 }
2067 /* A subroutine of fold_convert_const handling conversions a REAL_CST
2068 to a fixed-point type. */
2070 static tree
2072 {
2073 FIXED_VALUE_TYPE value;
2074 tree t;
2082 /* Propagate overflow flags. */
2086 }
2088 /* Attempt to fold type conversion operation CODE of expression ARG1 to
2089 type TYPE. If no simplification can be done return NULL_TREE. */
2091 static tree
2093 {
2099 {
2106 }
2108 {
2115 }
2117 {
2124 }
2126 {
2129 {
2134 {
2140 }
2142 }
2143 }
2145 }
2147 /* Construct a vector of zero elements of vector type TYPE. */
2149 static tree
2151 {
2152 tree t;
2156 }
2158 /* Returns true, if ARG is convertible to TYPE using a NOP_EXPR. */
2160 bool
2162 {
2177 {
2192 }
2193 }
2195 /* Convert expression ARG to type TYPE. Used by the middle-end for
2196 simple conversions in preference to calling the front-end's convert. */
2198 tree
2200 {
2202 tree tem;
2213 {
2216 /* Handle conversions between pointers to different address spaces. */
2221 /* fall through */
2226 {
2230 }
2244 {
2248 }
2250 {
2254 }
2256 {
2260 }
2263 {
2281 }
2286 {
2290 }
2293 {
2307 }
2311 {
2320 integer_zero_node));
2322 {
2326 {
2332 }
2340 }
2344 }
2362 }
2363 fold_convert_exit:
2366 }
2367 \f
2368 /* Return false if expr can be assumed not to be an lvalue, true
2369 otherwise. */
2371 static bool
2373 {
2374 /* We only need to wrap lvalue tree codes. */
2376 {
2407 /* Assume the worst for front-end tree codes. */
2411 }
2414 }
2416 /* Return an expr equal to X but certainly not valid as an lvalue. */
2418 tree
2420 {
2421 /* While we are in GIMPLE, NON_LVALUE_EXPR doesn't mean anything to
2422 us. */
2429 }
2431 /* When pedantic, return an expr equal to X but certainly not valid as a
2432 pedantic lvalue. Otherwise, return X. */
2434 static tree
2436 {
2438 }
2439 \f
2440 /* Given a tree comparison code, return the code that is the logical inverse.
2441 It is generally not safe to do this for floating-point comparisons, except
2442 for EQ_EXPR, NE_EXPR, ORDERED_EXPR and UNORDERED_EXPR, so we return
2443 ERROR_MARK in this case. */
2445 enum tree_code
2447 {
2453 {
2484 }
2485 }
2487 /* Similar, but return the comparison that results if the operands are
2488 swapped. This is safe for floating-point. */
2490 enum tree_code
2492 {
2494 {
2520 }
2521 }
2524 /* Convert a comparison tree code from an enum tree_code representation
2525 into a compcode bit-based encoding. This function is the inverse of
2526 compcode_to_comparison. */
2528 static enum comparison_code
2530 {
2532 {
2563 }
2564 }
2566 /* Convert a compcode bit-based encoding of a comparison operator back
2567 to GCC's enum tree_code representation. This function is the
2568 inverse of comparison_to_compcode. */
2570 static enum tree_code
2572 {
2574 {
2605 }
2606 }
2608 /* Return a tree for the comparison which is the combination of
2609 doing the AND or OR (depending on CODE) of the two operations LCODE
2610 and RCODE on the identical operands LL_ARG and LR_ARG. Take into account
2611 the possibility of trapping if the mode has NaNs, and return NULL_TREE
2612 if this makes the transformation invalid. */
2614 tree
2619 {
2626 {
2637 }
2640 {
2641 /* Eliminate unordered comparisons, as well as LTGT and ORD
2642 which are not used unless the mode has NaNs. */
2648 }
2650 {
2651 /* Check that the original operation and the optimized ones will trap
2652 under the same condition. */
2663 /* In a short-circuited boolean expression the LHS might be
2664 such that the RHS, if evaluated, will never trap. For
2665 example, in ORD (x, y) && (x < y), we evaluate the RHS only
2666 if neither x nor y is NaN. (This is a mixed blessing: for
2667 example, the expression above will never trap, hence
2668 optimizing it to x < y would be invalid). */
2673 /* If the comparison was short-circuited, and only the RHS
2674 trapped, we may now generate a spurious trap. */
2679 /* If we changed the conditions that cause a trap, we lose. */
2682 }
2688 else
2689 {
2694 }
2695 }
2696 \f
2697 /* Return nonzero if two operands (typically of the same tree node)
2698 are necessarily equal. FLAGS modifies behavior as follows:
2700 If OEP_ONLY_CONST is set, only return nonzero for constants.
2701 This function tests whether the operands are indistinguishable;
2702 it does not test whether they are equal using C's == operation.
2703 The distinction is important for IEEE floating point, because
2704 (1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
2705 (2) two NaNs may be indistinguishable, but NaN!=NaN.
2707 If OEP_ONLY_CONST is unset, a VAR_DECL is considered equal to itself
2708 even though it may hold multiple values during a function.
2709 This is because a GCC tree node guarantees that nothing else is
2710 executed between the evaluation of its "operands" (which may often
2711 be evaluated in arbitrary order). Hence if the operands themselves
2712 don't side-effect, the VAR_DECLs, PARM_DECLs etc... must hold the
2713 same value in each operand/subexpression. Hence leaving OEP_ONLY_CONST
2714 unset means assuming isochronic (or instantaneous) tree equivalence.
2715 Unless comparing arbitrary expression trees, such as from different
2716 statements, this flag can usually be left unset.
2718 If OEP_PURE_SAME is set, then pure functions with identical arguments
2719 are considered the same. It is used when the caller has other ways
2720 to ensure that global memory is unchanged in between.
2722 If OEP_ADDRESS_OF is set, we are actually comparing addresses of objects,
2723 not values of expressions.
2725 Unless OEP_MATCH_SIDE_EFFECTS is set, the function returns false on
2726 any operand with side effect. This is unnecesarily conservative in the
2727 case we know that arg0 and arg1 are in disjoint code paths (such as in
2728 ?: operator). In addition OEP_MATCH_SIDE_EFFECTS is used when comparing
2729 addresses with TREE_CONSTANT flag set so we know that &var == &var
2730 even if var is volatile. */
2732 int
2734 {
2735 /* When checking, verify at the outermost operand_equal_p call that
2736 if operand_equal_p returns non-zero then ARG0 and ARG1 has the same
2737 hash value. */
2739 {
2741 {
2743 {
2750 }
2752 }
2753 else
2755 }
2757 /* If either is ERROR_MARK, they aren't equal. */
2763 /* Similar, if either does not have a type (like a released SSA name),
2764 they aren't equal. */
2768 /* We cannot consider pointers to different address space equal. */
2775 /* Check equality of integer constants before bailing out due to
2776 precision differences. */
2778 {
2779 /* Address of INTEGER_CST is not defined; check that we did not forget
2780 to drop the OEP_ADDRESS_OF flags. */
2783 }
2786 {
2787 /* If both types don't have the same signedness, then we can't consider
2788 them equal. We must check this before the STRIP_NOPS calls
2789 because they may change the signedness of the arguments. As pointers
2790 strictly don't have a signedness, require either two pointers or
2791 two non-pointers as well. */
2797 /* If both types don't have the same precision, then it is not safe
2798 to strip NOPs. */
2805 }
2806 #if 0
2807 /* FIXME: Fortran FE currently produce ADDR_EXPR of NOP_EXPR. Enable the
2808 sanity check once the issue is solved. */
2809 else
2810 /* Addresses of conversions and SSA_NAMEs (and many other things)
2811 are not defined. Check that we did not forget to drop the
2812 OEP_ADDRESS_OF/OEP_CONSTANT_ADDRESS_OF flags. */
2815 #endif
2817 /* In case both args are comparisons but with different comparison
2818 code, try to swap the comparison operands of one arg to produce
2819 a match and compare that variant. */
2823 {
2831 }
2834 {
2835 /* NOP_EXPR and CONVERT_EXPR are considered equal. */
2837 ;
2839 {
2840 /* If we are interested in comparing addresses ignore
2841 MEM_REF wrappings of the base that can appear just for
2842 TBAA reasons. */
2856 }
2857 else
2859 }
2861 /* When not checking adddresses, this is needed for conversions and for
2862 COMPONENT_REF. Might as well play it safe and always test this. */
2869 /* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
2870 We don't care about side effects in that case because the SAVE_EXPR
2871 takes care of that for us. In all other cases, two expressions are
2872 equal if they have no side effects. If we have two identical
2873 expressions with side effects that should be treated the same due
2874 to the only side effects being identical SAVE_EXPR's, that will
2875 be detected in the recursive calls below.
2876 If we are taking an invariant address of two identical objects
2877 they are necessarily equal as well. */
2884 /* Next handle constant cases, those for which we can return 1 even
2885 if ONLY_CONST is set. */
2888 {
2902 {
2903 /* If we do not distinguish between signed and unsigned zero,
2904 consider them equal. */
2907 }
2911 {
2918 {
2922 }
2924 }
2928 flags)
2930 flags));
2941 flags | OEP_ADDRESS_OF
2944 /* In GIMPLE empty constructors are allowed in initializers of
2945 aggregates. */
2949 }
2954 /* Define macros to test an operand from arg0 and arg1 for equality and a
2955 variant that allows null and views null as being different from any
2956 non-null value. In the latter case, if either is null, the both
2957 must be; otherwise, do the normal comparison. */
2958 #define OP_SAME(N) operand_equal_p (TREE_OPERAND (arg0, N), \
2959 TREE_OPERAND (arg1, N), flags)
2961 #define OP_SAME_WITH_NULL(N) \
2962 ((!TREE_OPERAND (arg0, N) || !TREE_OPERAND (arg1, N)) \
2963 ? TREE_OPERAND (arg0, N) == TREE_OPERAND (arg1, N) : OP_SAME (N))
2966 {
2968 /* Two conversions are equal only if signedness and modes match. */
2970 {
2971 CASE_CONVERT:
2979 }
2989 /* For commutative ops, allow the other order. */
2997 /* If either of the pointer (or reference) expressions we are
2998 dereferencing contain a side effect, these cannot be equal,
2999 but their addresses can be. */
3006 {
3016 /* Require the same offset. */
3022 /* Fallthru. */
3030 {
3031 /* Require equal access sizes */
3037 flags)))
3039 /* Verify that access happens in similar types. */
3042 /* Verify that accesses are TBAA compatible. */
3051 /* Verify that alignment is compatible. */
3055 }
3058 /* TARGET_MEM_REF require equal extra operands. */
3069 /* Compare the array index by value if it is constant first as we
3070 may have different types but same value here. */
3076 /* Compare low bound and element size as with OEP_ADDRESS_OF
3077 we have to account for the offset of the ref. */
3082 array_ref_low_bound
3086 array_ref_element_size
3088 flags))));
3091 /* Handle operand 2 the same as for ARRAY_REF. Operand 0
3092 may be NULL when we're called to compare MEM_EXPRs. */
3107 }
3111 {
3113 /* Be sure we pass right ADDRESS_OF flag. */
3131 /* The multiplcation operands are commutative. */
3132 /* FALLTHRU */
3140 /* Otherwise take into account this is a commutative operation. */
3159 }
3163 {
3167 /* If not both CALL_EXPRs are either internal or normal function
3168 functions, then they are not equal. */
3171 {
3172 /* If the CALL_EXPRs call different internal functions, then they
3173 are not equal. */
3176 }
3177 else
3178 {
3179 /* If the CALL_EXPRs call different functions, then they are not
3180 equal. */
3182 flags))
3184 }
3186 /* FIXME: We could skip this test for OEP_MATCH_SIDE_EFFECTS. */
3187 {
3191 else
3195 }
3197 /* Now see if all the arguments are the same. */
3198 {
3209 /* If we get here and both argument lists are exhausted
3210 then the CALL_EXPRs are equal. */
3212 }
3215 }
3218 /* Consider __builtin_sqrt equal to sqrt. */
3226 {
3227 /* In GIMPLE constructors are used only to build vectors from
3228 elements. Individual elements in the constructor must be
3229 indexed in increasing order and form an initial sequence.
3231 We make no effort to compare constructors in generic.
3232 (see sem_variable::equals in ipa-icf which can do so for
3233 constants). */
3238 /* Be sure that vectors constructed have the same representation.
3239 We only tested element precision and modes to match.
3240 Vectors may be BLKmode and thus also check that the number of
3241 parts match. */
3254 {
3259 /* In GIMPLE the indexes can be either NULL or matching i.
3260 Double check this so we won't get false
3261 positives for GENERIC. */
3269 }
3271 }
3276 }
3278 #undef OP_SAME
3279 #undef OP_SAME_WITH_NULL
3280 }
3281 \f
3282 /* Similar to operand_equal_p, but see if ARG0 might have been made by
3283 shorten_compare from ARG1 when ARG1 was being compared with OTHER.
3285 When in doubt, return 0. */
3287 static int
3289 {
3301 /* Discard any conversions that don't change the modes of ARG0 and ARG1
3302 and see if the inner values are the same. This removes any
3303 signedness comparison, which doesn't matter here. */
3310 /* Duplicate what shorten_compare does to ARG1 and see if that gives the
3311 actual comparison operand, ARG0.
3313 First throw away any conversions to wider types
3314 already present in the operands. */
3323 {
3326 /* Make sure shorter operand is extended the right way
3327 to match the longer operand. */
3333 }
3336 }
3337 \f
3338 /* See if ARG is an expression that is either a comparison or is performing
3339 arithmetic on comparisons. The comparisons must only be comparing
3340 two different values, which will be stored in *CVAL1 and *CVAL2; if
3341 they are nonzero it means that some operands have already been found.
3342 No variables may be used anywhere else in the expression except in the
3343 comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
3344 the expression and save_expr needs to be called with CVAL1 and CVAL2.
3346 If this is true, return 1. Otherwise, return zero. */
3348 static int
3350 {
3354 /* We can handle some of the tcc_expression cases here. */
3364 {
3365 /* If we've already found a CVAL1 or CVAL2, this expression is
3366 two complex to handle. */
3372 }
3375 {
3398 /* First see if we can handle the first operand, then the second. For
3399 the second operand, we know *CVAL1 can't be zero. It must be that
3400 one side of the comparison is each of the values; test for the
3401 case where this isn't true by failing if the two operands
3402 are the same. */
3411 ;
3415 ;
3416 else
3420 ;
3424 ;
3425 else
3432 }
3433 }
3434 \f
3435 /* ARG is a tree that is known to contain just arithmetic operations and
3436 comparisons. Evaluate the operations in the tree substituting NEW0 for
3437 any occurrence of OLD0 as an operand of a comparison and likewise for
3438 NEW1 and OLD1. */
3440 static tree
3443 {
3448 /* We can handle some of the tcc_expression cases here. */
3456 {
3471 {
3490 }
3491 /* Fall through - ??? */
3494 {
3498 /* We need to check both for exact equality and tree equality. The
3499 former will be true if the operand has a side-effect. In that
3500 case, we know the operand occurred exactly once. */
3513 }
3517 }
3518 }
3519 \f
3520 /* Return a tree for the case when the result of an expression is RESULT
3521 converted to TYPE and OMITTED was previously an operand of the expression
3522 but is now not needed (e.g., we folded OMITTED * 0).
3524 If OMITTED has side effects, we must evaluate it. Otherwise, just do
3525 the conversion of RESULT to TYPE. */
3527 tree
3529 {
3532 /* If the resulting operand is an empty statement, just return the omitted
3533 statement casted to void. */
3543 }
3545 /* Return a tree for the case when the result of an expression is RESULT
3546 converted to TYPE and OMITTED1 and OMITTED2 were previously operands
3547 of the expression but are now not needed.
3549 If OMITTED1 or OMITTED2 has side effects, they must be evaluated.
3550 If both OMITTED1 and OMITTED2 have side effects, OMITTED1 is
3551 evaluated before OMITTED2. Otherwise, if neither has side effects,
3552 just do the conversion of RESULT to TYPE. */
3554 tree
3557 {
3566 }
3568 \f
3569 /* Return a simplified tree node for the truth-negation of ARG. This
3570 never alters ARG itself. We assume that ARG is an operation that
3571 returns a truth value (0 or 1).
3573 FIXME: one would think we would fold the result, but it causes
3574 problems with the dominator optimizer. */
3576 static tree
3578 {
3583 /* If this is a comparison, we can simply invert it, except for
3584 floating-point non-equality comparisons, in which case we just
3585 enclose a TRUTH_NOT_EXPR around what we have. */
3588 {
3591 && flag_trapping_math
3605 }
3608 {
3627 /* Here we can invert either operand. We invert the first operand
3628 unless the second operand is a TRUTH_NOT_EXPR in which case our
3629 result is the XOR of the first operand with the inside of the
3630 negation of the second operand. */
3635 else
3658 {
3665 /* A COND_EXPR may have a throw as one operand, which
3666 then has void type. Just leave void operands
3667 as they are. */
3673 }
3685 CASE_CONVERT:
3689 /* fall through */
3711 }
3712 }
3714 /* Fold the truth-negation of ARG. This never alters ARG itself. We
3715 assume that ARG is an operation that returns a truth value (0 or 1
3716 for scalars, 0 or -1 for vectors). Return the folded expression if
3717 folding is successful. Otherwise, return NULL_TREE. */
3719 static tree
3721 {
3724 ? BIT_NOT_EXPR
3727 }
3729 /* Return a simplified tree node for the truth-negation of ARG. This
3730 never alters ARG itself. We assume that ARG is an operation that
3731 returns a truth value (0 or 1 for scalars, 0 or -1 for vectors). */
3733 tree
3735 {
3741 ? BIT_NOT_EXPR
3744 }
3746 /* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation
3747 with code CODE. This optimization is unsafe. */
3748 static tree
3751 {
3755 /* (A / C) +- (B / C) -> (A +- B) / C. */
3765 /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */
3770 {
3782 }
3785 }
3786 \f
3787 /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
3788 starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero
3789 and uses reverse storage order if REVERSEP is nonzero. ORIG_INNER
3790 is the original memory reference used to preserve the alias set of
3791 the access. */
3793 static tree
3797 {
3807 {
3814 }
3829 }
3831 /* Optimize a bit-field compare.
3833 There are two cases: First is a compare against a constant and the
3834 second is a comparison of two items where the fields are at the same
3835 bit position relative to the start of a chunk (byte, halfword, word)
3836 large enough to contain it. In these cases we can avoid the shift
3837 implicit in bitfield extractions.
3839 For constants, we emit a compare of the shifted constant with the
3840 BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
3841 compared. For two fields at the same position, we do the ANDs with the
3842 similar mask and compare the result of the ANDs.
3844 CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
3845 COMPARE_TYPE is the type of the comparison, and LHS and RHS
3846 are the left and right operands of the comparison, respectively.
3848 If the optimization described above can be done, we return the resulting
3849 tree. Otherwise we return zero. */
3851 static tree
3854 {
3857 tree unsigned_type;
3864 tree mask;
3865 tree offset;
3867 /* Get all the information about the extractions being done. If the bit size
3868 if the same as the size of the underlying object, we aren't doing an
3869 extraction at all and so can do nothing. We also don't want to
3870 do anything if the inner expression is a PLACEHOLDER_EXPR since we
3871 then will no longer be able to replace it. */
3880 else
3881 {
3882 /* If this is not a constant, we can only do something if bit positions,
3883 sizes, signedness and storage order are the same. */
3884 rinner
3892 }
3894 /* Honor the C++ memory model and mimic what RTL expansion does. */
3898 {
3902 }
3904 /* See if we can find a mode to refer to this field. We should be able to,
3905 but fail if we can't. */
3914 /* Set signed and unsigned types of the precision of this mode for the
3915 shifts below. */
3918 /* Compute the bit position and size for the new reference and our offset
3919 within it. If the new reference is the same size as the original, we
3920 won't optimize anything, so return zero. */
3930 /* Make the mask to be used against the extracted field. */
3937 /* If not comparing with constant, just rework the comparison
3938 and return. */
3942 unsigned_type,
3945 mask),
3948 unsigned_type,
3951 mask));
3953 /* Otherwise, we are handling the constant case. See if the constant is too
3954 big for the field. Warn and return a tree for 0 (false) if so. We do
3955 this not only for its own sake, but to avoid having to test for this
3956 error case below. If we didn't, we might generate wrong code.
3958 For unsigned fields, the constant shifted right by the field length should
3959 be all zero. For signed fields, the high-order bits should agree with
3960 the sign bit. */
3963 {
3965 {
3969 }
3970 }
3971 else
3972 {
3975 {
3979 }
3980 }
3982 /* Single-bit compares should always be against zero. */
3984 {
3987 }
3989 /* Make a new bitfield reference, shift the constant over the
3990 appropriate number of bits and mask it with the computed mask
3991 (in case this was a signed field). If we changed it, make a new one. */
3999 mask);
4004 }
4005 \f
4006 /* Subroutine for fold_truth_andor_1: decode a field reference.
4008 If EXP is a comparison reference, we return the innermost reference.
4010 *PBITSIZE is set to the number of bits in the reference, *PBITPOS is
4011 set to the starting bit number.
4013 If the innermost field can be completely contained in a mode-sized
4014 unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
4016 *PVOLATILEP is set to 1 if the any expression encountered is volatile;
4017 otherwise it is not changed.
4019 *PUNSIGNEDP is set to the signedness of the field.
4021 *PREVERSEP is set to the storage order of the field.
4023 *PMASK is set to the mask used. This is either contained in a
4024 BIT_AND_EXPR or derived from the width of the field.
4026 *PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
4028 Return 0 if this is not a component reference or is one that we can't
4029 do anything with. */
4031 static tree
4036 {
4041 tree unsigned_type;
4044 /* All the optimizations using this function assume integer fields.
4045 There are problems with FP fields since the type_for_size call
4046 below can fail for, e.g., XFmode. */
4050 /* We are interested in the bare arrangement of bits, so strip everything
4051 that doesn't affect the machine mode. However, record the type of the
4052 outermost expression if it may matter below. */
4059 {
4065 }
4076 /* If the number of bits in the reference is the same as the bitsize of
4077 the outer type, then the outer type gives the signedness. Otherwise
4078 (in case of a small bitfield) the signedness is unchanged. */
4082 /* Compute the mask to access the bitfield. */
4091 /* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
4099 }
4101 /* Return nonzero if MASK represents a mask of SIZE ones in the low-order
4102 bit positions and MASK is SIGNED. */
4104 static int
4106 {
4110 /* If this function returns true when the type of the mask is
4111 UNSIGNED, then there will be errors. In particular see
4112 gcc.c-torture/execute/990326-1.c. There does not appear to be
4113 any documentation paper trail as to why this is so. But the pre
4114 wide-int worked with that restriction and it has been preserved
4115 here. */
4120 }
4122 /* Subroutine for fold: determine if VAL is the INTEGER_CONST that
4123 represents the sign bit of EXP's type. If EXP represents a sign
4124 or zero extension, also test VAL against the unextended type.
4125 The return value is the (sub)expression whose sign bit is VAL,
4126 or NULL_TREE otherwise. */
4128 tree
4130 {
4132 tree t;
4134 /* Tree EXP must have an integral type. */
4139 /* Tree VAL must be an integer constant. */
4148 /* Handle extension from a narrower type. */
4154 }
4156 /* Subroutine for fold_truth_andor_1: determine if an operand is simple enough
4157 to be evaluated unconditionally. */
4159 static int
4161 {
4162 /* Strip any conversions that don't change the machine mode. */
4171 /* Don't regard global variables as simple. They may be
4172 allocated in ways unknown to the compiler (shared memory,
4173 #pragma weak, etc). */
4176 /* Weakrefs are not safe to be read, since they can be NULL.
4177 They are !TREE_PUBLIC && !DECL_EXTERNAL but still
4178 have DECL_WEAK flag set. */
4180 /* Loading a static variable is unduly expensive, but global
4181 registers aren't expensive. */
4183 }
4185 /* Subroutine for fold_truth_andor: determine if an operand is simple enough
4186 to be evaluated unconditionally.
4187 I addition to simple_operand_p, we assume that comparisons, conversions,
4188 and logic-not operations are simple, if their operands are simple, too. */
4190 static bool
4192 {
4212 }
4214 \f
4215 /* The following functions are subroutines to fold_range_test and allow it to
4216 try to change a logical combination of comparisons into a range test.
4218 For example, both
4219 X == 2 || X == 3 || X == 4 || X == 5
4220 and
4221 X >= 2 && X <= 5
4222 are converted to
4223 (unsigned) (X - 2) <= 3
4225 We describe each set of comparisons as being either inside or outside
4226 a range, using a variable named like IN_P, and then describe the
4227 range with a lower and upper bound. If one of the bounds is omitted,
4228 it represents either the highest or lowest value of the type.
4230 In the comments below, we represent a range by two numbers in brackets
4231 preceded by a "+" to designate being inside that range, or a "-" to
4232 designate being outside that range, so the condition can be inverted by
4233 flipping the prefix. An omitted bound is represented by a "-". For
4234 example, "- [-, 10]" means being outside the range starting at the lowest
4235 possible value and ending at 10, in other words, being greater than 10.
4236 The range "+ [-, -]" is always true and hence the range "- [-, -]" is
4237 always false.
4239 We set up things so that the missing bounds are handled in a consistent
4240 manner so neither a missing bound nor "true" and "false" need to be
4241 handled using a special case. */
4243 /* Return the result of applying CODE to ARG0 and ARG1, but handle the case
4244 of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
4245 and UPPER1_P are nonzero if the respective argument is an upper bound
4246 and zero for a lower. TYPE, if nonzero, is the type of the result; it
4247 must be specified for a comparison. ARG1 will be converted to ARG0's
4248 type if both are specified. */
4250 static tree
4253 {
4254 tree tem;
4258 /* If neither arg represents infinity, do the normal operation.
4259 Else, if not a comparison, return infinity. Else handle the special
4260 comparison rules. Note that most of the cases below won't occur, but
4261 are handled for consistency. */
4264 {
4269 }
4274 /* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
4275 for neither. In real maths, we cannot assume open ended ranges are
4276 the same. But, this is computer arithmetic, where numbers are finite.
4277 We can therefore make the transformation of any unbounded range with
4278 the value Z, Z being greater than any representable number. This permits
4279 us to treat unbounded ranges as equal. */
4283 {
4304 }
4307 }
4308 \f
4309 /* Helper routine for make_range. Perform one step for it, return
4310 new expression if the loop should continue or NULL_TREE if it should
4311 stop. */
4313 tree
4317 {
4323 {
4325 /* We can only do something if the range is testing for zero. */
4334 /* We can only do something if the range is testing for zero
4335 and if the second operand is an integer constant. Note that
4336 saying something is "in" the range we make is done by
4337 complementing IN_P since it will set in the initial case of
4338 being not equal to zero; "out" is leaving it alone. */
4345 {
4366 }
4368 /* If this is an unsigned comparison, we also know that EXP is
4369 greater than or equal to zero. We base the range tests we make
4370 on that fact, so we record it here so we can parse existing
4371 range tests. We test arg0_type since often the return type
4372 of, e.g. EQ_EXPR, is boolean. */
4374 {
4378 NULL_TREE))
4383 /* If the high bound is missing, but we have a nonzero low
4384 bound, reverse the range so it goes from zero to the low bound
4385 minus 1. */
4387 {
4392 }
4393 }
4401 /* If flag_wrapv and ARG0_TYPE is signed, make sure
4402 low and high are non-NULL, then normalize will DTRT. */
4405 {
4410 }
4412 /* (-x) IN [a,b] -> x in [-b, -a] */
4424 /* ~ X -> -X - 1 */
4433 /* If flag_wrapv and ARG0_TYPE is signed, then we cannot
4434 move a constant to the other side. */
4439 /* If EXP is signed, any overflow in the computation is undefined,
4440 so we don't worry about it so long as our computations on
4441 the bounds don't overflow. For unsigned, overflow is defined
4442 and this is exactly the right thing. */
4454 normalize:
4455 /* Check for an unsigned range which has wrapped around the maximum
4456 value thus making n_high < n_low, and normalize it. */
4458 {
4464 /* If the range is of the form +/- [ x+1, x ], we won't
4465 be able to normalize it. But then, it represents the
4466 whole range or the empty set, so make it
4467 +/- [ -, - ]. */
4471 else
4473 }
4474 else
4482 CASE_CONVERT:
4500 /* If we're converting arg0 from an unsigned type, to exp,
4501 a signed type, we will be doing the comparison as unsigned.
4502 The tests above have already verified that LOW and HIGH
4503 are both positive.
4505 So we have to ensure that we will handle large unsigned
4506 values the same way that the current signed bounds treat
4507 negative values. */
4510 {
4511 tree high_positive;
4512 tree equiv_type;
4513 /* For fixed-point modes, we need to pass the saturating flag
4514 as the 2nd parameter. */
4516 equiv_type
4519 else
4520 equiv_type
4523 /* A range without an upper bound is, naturally, unbounded.
4524 Since convert would have cropped a very large value, use
4525 the max value for the destination type. */
4526 high_positive
4533 high_positive),
4536 /* If the low bound is specified, "and" the range with the
4537 range for which the original unsigned value will be
4538 positive. */
4540 {
4543 integer_zero_node),
4544 high_positive))
4548 }
4549 else
4550 {
4551 /* Otherwise, "or" the range with the range of the input
4552 that will be interpreted as negative. */
4555 integer_zero_node),
4556 high_positive))
4560 }
4561 }
4570 }
4571 }
4573 /* Given EXP, a logical expression, set the range it is testing into
4574 variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
4575 actually being tested. *PLOW and *PHIGH will be made of the same
4576 type as the returned expression. If EXP is not a comparison, we
4577 will most likely not be returning a useful value and range. Set
4578 *STRICT_OVERFLOW_P to true if the return value is only valid
4579 because signed overflow is undefined; otherwise, do not change
4580 *STRICT_OVERFLOW_P. */
4582 tree
4585 {
4593 /* Start with simply saying "EXP != 0" and then look at the code of EXP
4594 and see if we can refine the range. Some of the cases below may not
4595 happen, but it doesn't seem worth worrying about this. We "continue"
4596 the outer loop when we've changed something; otherwise we "break"
4597 the switch, which will "break" the while. */
4603 {
4609 {
4617 }
4626 }
4628 /* If EXP is a constant, we can evaluate whether this is true or false. */
4630 {
4637 }
4641 }
4642 \f
4643 /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
4644 type, TYPE, return an expression to test if EXP is in (or out of, depending
4645 on IN_P) the range. Return 0 if the test couldn't be created. */
4647 tree
4650 {
4653 /* Disable this optimization for function pointer expressions
4654 on targets that require function pointer canonicalization. */
4661 {
4667 }
4685 {
4687 {
4691 }
4693 }
4695 /* Optimize (c>=1) && (c<=127) into (signed char)c > 0. */
4697 {
4701 {
4703 {
4706 etype
4708 else
4711 }
4714 }
4715 }
4717 /* Optimize (c>=low) && (c<=high) into (c-low>=0) && (c-low<=high-low).
4718 This requires wrap-around arithmetics for the type of the expression.
4719 First make sure that arithmetics in this type is valid, then make sure
4720 that it wraps around. */
4726 {
4729 /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN
4730 for the type in question, as we rely on this here. */
4740 else
4742 }
4752 {
4754 {
4759 }
4761 }
4769 }
4770 \f
4771 /* Return the predecessor of VAL in its type, handling the infinite case. */
4773 static tree
4775 {
4781 else
4784 }
4786 /* Return the successor of VAL in its type, handling the infinite case. */
4788 static tree
4790 {
4796 else
4799 }
4801 /* Given two ranges, see if we can merge them into one. Return 1 if we
4802 can, 0 if we can't. Set the output range into the specified parameters. */
4804 bool
4807 {
4811 tree tem;
4821 /* Make range 0 be the range that starts first, or ends last if they
4822 start at the same value. Swap them if it isn't. */
4825 || (lowequal
4828 {
4832 }
4834 /* Now flag two cases, whether the ranges are disjoint or whether the
4835 second range is totally subsumed in the first. Note that the tests
4836 below are simplified by the ones above. */
4842 /* We now have four cases, depending on whether we are including or
4843 excluding the two ranges. */
4845 {
4846 /* If they don't overlap, the result is false. If the second range
4847 is a subset it is the result. Otherwise, the range is from the start
4848 of the second to the end of the first. */
4853 else
4855 }
4858 {
4859 /* If they don't overlap, the result is the first range. If they are
4860 equal, the result is false. If the second range is a subset of the
4861 first, and the ranges begin at the same place, we go from just after
4862 the end of the second range to the end of the first. If the second
4863 range is not a subset of the first, or if it is a subset and both
4864 ranges end at the same place, the range starts at the start of the
4865 first range and ends just before the second range.
4866 Otherwise, we can't describe this as a single range. */
4872 {
4877 {
4878 /* We are in the weird situation where high0 > high1 but
4879 high1 has no successor. Punt. */
4881 }
4882 }
4884 {
4889 {
4890 /* low0 < low1 but low1 has no predecessor. Punt. */
4892 }
4893 }
4894 else
4896 }
4899 {
4900 /* If they don't overlap, the result is the second range. If the second
4901 is a subset of the first, the result is false. Otherwise,
4902 the range starts just after the first range and ends at the
4903 end of the second. */
4908 else
4909 {
4914 {
4915 /* high1 > high0 but high0 has no successor. Punt. */
4917 }
4918 }
4919 }
4921 else
4922 {
4923 /* The case where we are excluding both ranges. Here the complex case
4924 is if they don't overlap. In that case, the only time we have a
4925 range is if they are adjacent. If the second is a subset of the
4926 first, the result is the first. Otherwise, the range to exclude
4927 starts at the beginning of the first range and ends at the end of the
4928 second. */
4930 {
4935 else
4936 {
4937 /* Canonicalize - [min, x] into - [-, x]. */
4940 {
4945 /* FALLTHROUGH */
4958 }
4960 /* Canonicalize - [x, max] into - [x, -]. */
4963 {
4968 /* FALLTHROUGH */
4984 }
4986 /* The ranges might be also adjacent between the maximum and
4987 minimum values of the given type. For
4988 - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y
4989 return + [x + 1, y - 1]. */
4991 {
4998 }
4999 else
5001 }
5002 }
5005 else
5007 }
5011 }
5012 \f
5014 /* Subroutine of fold, looking inside expressions of the form
5015 A op B ? A : C, where ARG0, ARG1 and ARG2 are the three operands
5016 of the COND_EXPR. This function is being used also to optimize
5017 A op B ? C : A, by reversing the comparison first.
5019 Return a folded expression whose code is not a COND_EXPR
5020 anymore, or NULL_TREE if no folding opportunity is found. */
5022 static tree
5025 {
5030 tree tem;
5035 /* If we have A op 0 ? A : -A, consider applying the following
5036 transformations:
5038 A == 0? A : -A same as -A
5039 A != 0? A : -A same as A
5040 A >= 0? A : -A same as abs (A)
5041 A > 0? A : -A same as abs (A)
5042 A <= 0? A : -A same as -abs (A)
5043 A < 0? A : -A same as -abs (A)
5045 None of these transformations work for modes with signed
5046 zeros. If A is +/-0, the first two transformations will
5047 change the sign of the result (from +0 to -0, or vice
5048 versa). The last four will fix the sign of the result,
5049 even though the original expressions could be positive or
5050 negative, depending on the sign of A.
5052 Note that all these transformations are correct if A is
5053 NaN, since the two alternatives (A and -A) are also NaNs. */
5060 /* In the case that A is of the form X-Y, '-A' (arg2) may
5061 have already been folded to Y-X, check for that. */
5069 {
5081 /* Fall through. */
5092 /* FALLTHRU */
5102 }
5104 /* A != 0 ? A : 0 is simply A, unless A is -0. Likewise
5105 A == 0 ? A : 0 is always 0 unless A is -0. Note that
5106 both transformations are correct when A is NaN: A != 0
5107 is then true, and A == 0 is false. */
5111 {
5116 }
5118 /* Try some transformations of A op B ? A : B.
5120 A == B? A : B same as B
5121 A != B? A : B same as A
5122 A >= B? A : B same as max (A, B)
5123 A > B? A : B same as max (B, A)
5124 A <= B? A : B same as min (A, B)
5125 A < B? A : B same as min (B, A)
5127 As above, these transformations don't work in the presence
5128 of signed zeros. For example, if A and B are zeros of
5129 opposite sign, the first two transformations will change
5130 the sign of the result. In the last four, the original
5131 expressions give different results for (A=+0, B=-0) and
5132 (A=-0, B=+0), but the transformed expressions do not.
5134 The first two transformations are correct if either A or B
5135 is a NaN. In the first transformation, the condition will
5136 be false, and B will indeed be chosen. In the case of the
5137 second transformation, the condition A != B will be true,
5138 and A will be chosen.
5140 The conversions to max() and min() are not correct if B is
5141 a number and A is not. The conditions in the original
5142 expressions will be false, so all four give B. The min()
5143 and max() versions would give a NaN instead. */
5146 /* Avoid these transformations if the COND_EXPR may be used
5147 as an lvalue in the C++ front-end. PR c++/19199. */
5148 && (in_gimple_form
5154 {
5160 {
5169 /* In C++ a ?: expression can be an lvalue, so put the
5170 operand which will be used if they are equal first
5171 so that we can convert this back to the
5172 corresponding COND_EXPR. */
5174 {
5182 }
5189 {
5197 }
5210 }
5211 }
5214 }
5217 \f
5218 #ifndef LOGICAL_OP_NON_SHORT_CIRCUIT
5219 #define LOGICAL_OP_NON_SHORT_CIRCUIT \
5220 (BRANCH_COST (optimize_function_for_speed_p (cfun), \
5221 false) >= 2)
5222 #endif
5224 /* EXP is some logical combination of boolean tests. See if we can
5225 merge it into some range test. Return the new tree if so. */
5227 static tree
5230 {
5246 /* If this is an OR operation, invert both sides; we will invert
5247 again at the end. */
5251 /* If both expressions are the same, if we can merge the ranges, and we
5252 can build the range test, return it or it inverted. If one of the
5253 ranges is always true or always false, consider it to be the same
5254 expression as the other. */
5262 {
5266 }
5268 /* On machines where the branch cost is expensive, if this is a
5269 short-circuited branch and the underlying object on both sides
5270 is the same, make a non-short-circuit operation. */
5276 {
5277 /* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
5278 unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
5279 which cases we can't do this. */
5287 {
5296 {
5299 WARN_STRICT_OVERFLOW_COMPARISON);
5303 }
5304 }
5305 }
5308 }
5309 \f
5310 /* Subroutine for fold_truth_andor_1: C is an INTEGER_CST interpreted as a P
5311 bit value. Arrange things so the extra bits will be set to zero if and
5312 only if C is signed-extended to its full width. If MASK is nonzero,
5313 it is an INTEGER_CST that should be AND'ed with the extra bits. */
5315 static tree
5317 {
5320 tree temp;
5325 /* We work by getting just the sign bit into the low-order bit, then
5326 into the high-order bit, then sign-extend. We then XOR that value
5327 with C. */
5330 /* We must use a signed type in order to get an arithmetic right shift.
5331 However, we must also avoid introducing accidental overflows, so that
5332 a subsequent call to integer_zerop will work. Hence we must
5333 do the type conversion here. At this point, the constant is either
5334 zero or one, and the conversion to a signed type can never overflow.
5335 We could get an overflow if this conversion is done anywhere else. */
5344 /* If necessary, convert the type back to match the type of C. */
5349 }
5350 \f
5351 /* For an expression that has the form
5352 (A && B) || ~B
5353 or
5354 (A || B) && ~B,
5355 we can drop one of the inner expressions and simplify to
5356 A || ~B
5357 or
5358 A && ~B
5359 LOC is the location of the resulting expression. OP is the inner
5360 logical operation; the left-hand side in the examples above, while CMPOP
5361 is the right-hand side. RHS_ONLY is used to prevent us from accidentally
5362 removing a condition that guards another, as in
5363 (A != NULL && A->...) || A == NULL
5364 which we must not transform. If RHS_ONLY is true, only eliminate the
5365 right-most operand of the inner logical operation. */
5367 static tree
5370 {
5388 {
5391 {
5394 }
5395 }
5397 {
5400 {
5403 }
5404 }
5419 }
5421 /* Find ways of folding logical expressions of LHS and RHS:
5422 Try to merge two comparisons to the same innermost item.
5423 Look for range tests like "ch >= '0' && ch <= '9'".
5424 Look for combinations of simple terms on machines with expensive branches
5425 and evaluate the RHS unconditionally.
5427 For example, if we have p->a == 2 && p->b == 4 and we can make an
5428 object large enough to span both A and B, we can do this with a comparison
5429 against the object ANDed with the a mask.
5431 If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
5432 operations to do this with one comparison.
5434 We check for both normal comparisons and the BIT_AND_EXPRs made this by
5435 function and the one above.
5437 CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
5438 TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
5440 TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
5441 two operands.
5443 We return the simplified tree or 0 if no optimization is possible. */
5445 static tree
5448 {
5449 /* If this is the "or" of two comparisons, we can do something if
5450 the comparisons are NE_EXPR. If this is the "and", we can do something
5451 if the comparisons are EQ_EXPR. I.e.,
5452 (a->b == 2 && a->c == 4) can become (a->new == NEW).
5454 WANTED_CODE is this operation code. For single bit fields, we can
5455 convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
5456 comparison for one-bit fields. */
5477 /* Start by getting the comparison codes. Fail if anything is volatile.
5478 If one operand is a BIT_AND_EXPR with the constant one, treat it as if
5479 it were surrounded with a NE_EXPR. */
5488 {
5492 }
5495 {
5499 }
5510 /* Simplify (x<y) && (x==y) into (x<=y) and related optimizations. */
5513 {
5516 {
5521 }
5524 {
5530 }
5531 }
5536 /* If the RHS can be evaluated unconditionally and its operands are
5537 simple, it wins to evaluate the RHS unconditionally on machines
5538 with expensive branches. In this case, this isn't a comparison
5539 that can be merged. */
5546 {
5547 /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
5558 /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
5568 }
5570 /* See if the comparisons can be merged. Then get all the parameters for
5571 each side. */
5596 /* It must be true that the inner operation on the lhs of each
5597 comparison must be the same if we are to be able to do anything.
5598 Then see if we have constants. If not, the same must be true for
5599 the rhs's. */
5608 {
5611 }
5616 else
5619 /* If either comparison code is not correct for our logical operation,
5620 fail. However, we can convert a one-bit comparison against zero into
5621 the opposite comparison against that bit being set in the field. */
5625 {
5627 {
5628 /* Make the left operand unsigned, since we are only interested
5629 in the value of one bit. Otherwise we are doing the wrong
5630 thing below. */
5633 }
5634 else
5636 }
5638 /* This is analogous to the code for l_const above. */
5640 {
5642 {
5645 }
5646 else
5648 }
5650 /* See if we can find a mode that contains both fields being compared on
5651 the left. If we can't, fail. Otherwise, update all constants and masks
5652 to be relative to a field of that size. */
5657 volatilep);
5667 {
5670 }
5678 {
5685 {
5689 }
5690 }
5692 {
5699 {
5703 }
5704 }
5706 /* If the right sides are not constant, do the same for it. Also,
5707 disallow this optimization if a size or signedness mismatch occurs
5708 between the left and right sides. */
5710 {
5713 /* Make sure the two fields on the right
5714 correspond to the left without being swapped. */
5722 volatilep);
5732 {
5735 }
5744 /* Make a mask that corresponds to both fields being compared.
5745 Do this for both items being compared. If the operands are the
5746 same size and the bits being compared are in the same position
5747 then we can do this by masking both and comparing the masked
5748 results. */
5752 {
5766 }
5768 /* There is still another way we can do something: If both pairs of
5769 fields being compared are adjacent, we may be able to make a wider
5770 field containing them both.
5772 Note that we still must mask the lhs/rhs expressions. Furthermore,
5773 the mask must be shifted to account for the shift done by
5774 make_bit_field_ref. */
5779 {
5780 tree type;
5796 /* Convert to the smaller type before masking out unwanted bits. */
5799 {
5801 {
5805 }
5807 {
5811 }
5812 }
5821 }
5824 }
5826 /* Handle the case of comparisons with constants. If there is something in
5827 common between the masks, those bits of the constants must be the same.
5828 If not, the condition is always false. Test for this to avoid generating
5829 incorrect code below. */
5834 {
5836 {
5839 }
5840 else
5841 {
5844 }
5845 }
5847 /* Construct the expression we will return. First get the component
5848 reference we will make. Unless the mask is all ones the width of
5849 that field, perform the mask operation. Then compare with the
5850 merged constant. */
5861 }
5862 \f
5863 /* T is an integer expression that is being multiplied, divided, or taken a
5864 modulus (CODE says which and what kind of divide or modulus) by a
5865 constant C. See if we can eliminate that operation by folding it with
5866 other operations already in T. WIDE_TYPE, if non-null, is a type that
5867 should be used for the computation if wider than our type.
5869 For example, if we are dividing (X * 8) + (Y * 16) by 4, we can return
5870 (X * 2) + (Y * 4). We must, however, be assured that either the original
5871 expression would not overflow or that overflow is undefined for the type
5872 in the language in question.
5874 If we return a non-null expression, it is an equivalent form of the
5875 original computation, but need not be in the original type.
5877 We set *STRICT_OVERFLOW_P to true if the return values depends on
5878 signed overflow being undefined. Otherwise we do not change
5879 *STRICT_OVERFLOW_P. */
5881 static tree
5884 {
5885 /* To avoid exponential search depth, refuse to allow recursion past
5886 three levels. Beyond that (1) it's highly unlikely that we'll find
5887 something interesting and (2) we've probably processed it before
5888 when we built the inner expression. */
5891 tree ret;
5896 depth++;
5898 depth--;
5901 }
5903 static tree
5906 {
5917 /* Don't deal with constants of zero here; they confuse the code below. */
5927 /* Note that we need not handle conditional operations here since fold
5928 already handles those cases. So just do arithmetic here. */
5930 {
5932 /* For a constant, we can always simplify if we are a multiply
5933 or (for divide and modulus) if it is a multiple of our constant. */
5936 {
5939 /* If the multiplication overflowed, we lost information on it.
5940 See PR68142 and PR69845. */
5944 }
5948 /* If op0 is an expression ... */
5954 /* ... and has wrapping overflow, and its type is smaller
5955 than ctype, then we cannot pass through as widening. */
5960 /* ... or this is a truncation (t is narrower than op0),
5961 then we cannot pass through this narrowing. */
5964 /* ... or signedness changes for division or modulus,
5965 then we cannot pass through this conversion. */
5969 /* ... or has undefined overflow while the converted to
5970 type has not, we cannot do the operation in the inner type
5971 as that would introduce undefined overflow. */
5977 /* Pass the constant down and see if we can make a simplification. If
5978 we can, replace this expression with the inner simplification for
5979 possible later conversion to our or some other type. */
5984 code == MULT_EXPR
5986 strict_overflow_p))))
5991 /* If widening the type changes it from signed to unsigned, then we
5992 must avoid building ABS_EXPR itself as unsigned. */
5994 {
5998 {
6001 }
6003 }
6004 /* If the constant is negative, we cannot simplify this. */
6007 /* FALLTHROUGH */
6009 /* For division and modulus, type can't be unsigned, as e.g.
6010 (-(x / 2U)) / 2U isn't equal to -((x / 2U) / 2U) for x >= 2.
6011 For signed types, even with wrapping overflow, this is fine. */
6020 /* If widening the type changes the signedness, then we can't perform
6021 this optimization as that changes the result. */
6025 /* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
6031 {
6038 }
6042 /* If the second operand is constant, this is a multiplication
6043 or floor division, by a power of two, so we can treat it that
6044 way unless the multiplier or divisor overflows. Signed
6045 left-shift overflow is implementation-defined rather than
6046 undefined in C90, so do not convert signed left shift into
6047 multiplication. */
6050 /* const_binop may not detect overflow correctly,
6051 so check for it explicitly here. */
6055 size_one_node,
6056 op1)))
6060 ctype,
6062 t1),
6067 /* See if we can eliminate the operation on both sides. If we can, we
6068 can return a new PLUS or MINUS. If we can't, the only remaining
6069 cases where we can do anything are if the second operand is a
6070 constant. */
6076 /* If not multiplication, we can only do this if both operands
6077 are divisible by c. */
6080 {
6085 }
6087 /* If this was a subtraction, negate OP1 and set it to be an addition.
6088 This simplifies the logic below. */
6090 {
6092 /* If OP1 was not easily negatable, the constant may be OP0. */
6094 {
6097 }
6098 }
6103 /* If either OP1 or C are negative, this optimization is not safe for
6104 some of the division and remainder types while for others we need
6105 to change the code. */
6107 {
6115 }
6117 /* If it's a multiply or a division/modulus operation of a multiple
6118 of our constant, do the operation and verify it doesn't overflow. */
6121 {
6124 /* We allow the constant to overflow with wrapping semantics. */
6128 }
6129 else
6132 /* If we have an unsigned type, we cannot widen the operation since it
6133 will change the result if the original computation overflowed. */
6137 /* If we were able to eliminate our operation from the first side,
6138 apply our operation to the second side and reform the PLUS. */
6142 /* The last case is if we are a multiply. In that case, we can
6143 apply the distributive law to commute the multiply and addition
6144 if the multiplication of the constants doesn't overflow
6145 and overflow is defined. With undefined overflow
6146 op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
6152 op1);
6157 /* We have a special case here if we are doing something like
6158 (C * 8) % 4 since we know that's zero. */
6161 /* If the multiplication can overflow we cannot optimize this. */
6165 {
6168 }
6170 /* ... fall through ... */
6174 /* If we can extract our operation from the LHS, do so and return a
6175 new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
6176 do something only if the second operand is a constant. */
6190 /* If these are the same operation types, we can associate them
6191 assuming no overflow. */
6193 {
6208 }
6210 /* If these operations "cancel" each other, we have the main
6211 optimizations of this pass, which occur when either constant is a
6212 multiple of the other, in which case we replace this with either an
6213 operation or CODE or TCODE.
6215 If we have an unsigned type, we cannot do this since it will change
6216 the result if the original computation overflowed. */
6223 {
6225 {
6232 }
6234 {
6241 }
6242 }
6247 }
6250 }
6251 \f
6252 /* Return a node which has the indicated constant VALUE (either 0 or
6253 1 for scalars or {-1,-1,..} or {0,0,...} for vectors),
6254 and is of the indicated TYPE. */
6256 tree
6258 {
6267 else
6269 }
6272 /* Transform `a + (b ? x : y)' into `b ? (a + x) : (a + y)'.
6273 Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
6274 CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
6275 expression, and ARG to `a'. If COND_FIRST_P is nonzero, then the
6276 COND is the first argument to CODE; otherwise (as in the example
6277 given here), it is the second argument. TYPE is the type of the
6278 original expression. Return NULL_TREE if no simplification is
6279 possible. */
6281 static tree
6286 {
6296 {
6300 /* If this operand throws an expression, then it does not make
6301 sense to try to perform a logical or arithmetic operation
6302 involving it. */
6307 }
6310 {
6315 }
6316 else
6317 /* Detect the case of mixing vector and scalar types - bail out. */
6323 /* This transformation is only worthwhile if we don't have to wrap ARG
6324 in a SAVE_EXPR and the operation can be simplified without recursing
6325 on at least one of the branches once its pushed inside the COND_EXPR. */
6334 {
6338 else
6340 }
6342 {
6346 else
6348 }
6350 /* Check that we have simplified at least one of the branches. */
6355 }
6357 \f
6358 /* Subroutine of fold() that checks for the addition of +/- 0.0.
6360 If !NEGATE, return true if ADDEND is +/-0.0 and, for all X of type
6361 TYPE, X + ADDEND is the same as X. If NEGATE, return true if X -
6362 ADDEND is the same as X.
6364 X + 0 and X - 0 both give X when X is NaN, infinite, or nonzero
6365 and finite. The problematic cases are when X is zero, and its mode
6366 has signed zeros. In the case of rounding towards -infinity,
6367 X - 0 is not the same as X because 0 - 0 is -0. In other rounding
6368 modes, X + 0 is not the same as X because -0 + 0 is 0. */
6370 bool
6372 {
6376 /* Don't allow the fold with -fsignaling-nans. */
6380 /* Allow the fold if zeros aren't signed, or their sign isn't important. */
6384 /* In a vector or complex, we would need to check the sign of all zeros. */
6388 /* Treat x + -0 as x - 0 and x - -0 as x + 0. */
6392 /* The mode has signed zeros, and we have to honor their sign.
6393 In this situation, there is only one case we can return true for.
6394 X - 0 is the same as X unless rounding towards -infinity is
6395 supported. */
6397 }
6399 /* Subroutine of fold() that optimizes comparisons of a division by
6400 a nonzero integer constant against an integer constant, i.e.
6401 X/C1 op C2.
6403 CODE is the comparison operator: EQ_EXPR, NE_EXPR, GT_EXPR, LT_EXPR,
6404 GE_EXPR or LE_EXPR. TYPE is the type of the result and ARG0 and ARG1
6405 are the operands of the comparison. ARG1 must be a TREE_REAL_CST.
6407 The function returns the constant folded tree if a simplification
6408 can be made, and NULL_TREE otherwise. */
6410 static tree
6413 {
6421 /* We have to do this the hard way to detect unsigned overflow.
6422 prod = int_const_binop (MULT_EXPR, arg01, arg1); */
6428 {
6433 /* Likewise hi = int_const_binop (PLUS_EXPR, prod, tmp). */
6437 }
6439 {
6443 {
6462 }
6463 }
6464 else
6465 {
6466 /* A negative divisor reverses the relational operators. */
6472 {
6491 }
6492 }
6495 {
6516 {
6519 }
6524 {
6527 }
6532 {
6535 }
6540 {
6543 }
6548 }
6551 }
6554 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6555 equality/inequality test, then return a simplified form of the test
6556 using a sign testing. Otherwise return NULL. TYPE is the desired
6557 result type. */
6559 static tree
6562 tree result_type)
6563 {
6564 /* If this is testing a single bit, we can optimize the test. */
6568 {
6569 /* If we have (A & C) != 0 where C is the sign bit of A, convert
6570 this into A < 0. Similarly for (A & C) == 0 into A >= 0. */
6574 /* This is only a win if casting to a signed type is cheap,
6575 i.e. when arg00's type is not a partial mode. */
6578 {
6581 result_type,
6584 }
6585 }
6588 }
6590 /* If CODE with arguments ARG0 and ARG1 represents a single bit
6591 equality/inequality test, then return a simplified form of
6592 the test using shifts and logical operations. Otherwise return
6593 NULL. TYPE is the desired result type. */
6595 tree
6598 {
6599 /* If this is testing a single bit, we can optimize the test. */
6603 {
6612 /* First, see if we can fold the single bit test into a sign-bit
6613 test. */
6615 result_type);
6619 /* Otherwise we have (A & C) != 0 where C is a single bit,
6620 convert that into ((A >> C2) & 1). Where C2 = log2(C).
6621 Similarly for (A & C) == 0. */
6623 /* If INNER is a right shift of a constant and it plus BITNUM does
6624 not overflow, adjust BITNUM and INNER. */
6630 {
6633 }
6635 /* If we are going to be able to omit the AND below, we must do our
6636 operations as unsigned. If we must use the AND, we have a choice.
6637 Normally unsigned is faster, but for some machines signed is. */
6655 /* Put the AND last so it can combine with more things. */
6658 /* Make sure to return the proper type. */
6662 }
6664 }
6666 /* Test whether it is preferable two swap two operands, ARG0 and
6667 ARG1, for example because ARG0 is an integer constant and ARG1
6668 isn't. */
6670 bool
6672 {
6686 /* It is preferable to swap two SSA_NAME to ensure a canonical form
6687 for commutative and comparison operators. Ensuring a canonical
6688 form allows the optimizers to find additional redundancies without
6689 having to explicitly check for both orderings. */
6695 /* Put SSA_NAMEs last. */
6701 /* Put variables last. */
6708 }
6711 /* Fold A < X && A + 1 > Y to A < X && A >= Y. Normally A + 1 > Y
6712 means A >= Y && A != MAX, but in this case we know that
6713 A < X <= MAX. INEQ is A + 1 > Y, BOUND is A < X. */
6715 static tree
6717 {
6724 else
6733 {
6736 }
6738 {
6741 }
6742 else
6749 {
6750 /* Convert the pointer types into integer before taking the difference. */
6754 }
6755 else
6762 }
6764 /* Fold a sum or difference of at least one multiplication.
6765 Returns the folded tree or NULL if no simplification could be made. */
6767 static tree
6770 {
6774 /* (A * C) +- (B * C) -> (A+-B) * C.
6775 (A * C) +- A -> A * (C+-1).
6776 We are most concerned about the case where C is a constant,
6777 but other combinations show up during loop reduction. Since
6778 it is not difficult, try all four possibilities. */
6781 {
6784 }
6786 {
6789 }
6790 else
6791 {
6792 /* We cannot generate constant 1 for fract. */
6797 }
6799 {
6802 }
6804 {
6806 /* As we canonicalize A - 2 to A + -2 get rid of that sign for
6807 the purpose of this canonicalization. */
6811 {
6814 }
6815 else
6817 }
6818 else
6819 {
6820 /* We cannot generate constant 1 for fract. */
6825 }
6837 /* No identical multiplicands; see if we can find a common
6838 power-of-two factor in non-power-of-two multiplies. This
6839 can help in multi-dimensional array access. */
6842 {
6845 tree maybe_same;
6849 /* Move min of absolute values to int11. */
6851 {
6856 }
6857 else
6861 /* The remainder should not be a constant, otherwise we
6862 end up folding i * 4 + 2 to (i * 2 + 1) * 2 which has
6863 increased the number of multiplications necessary. */
6865 {
6873 }
6874 }
6884 }
6886 /* Subroutine of native_encode_expr. Encode the INTEGER_CST
6887 specified by EXPR into the buffer PTR of length LEN bytes.
6888 Return the number of bytes placed in the buffer, or zero
6889 upon failure. */
6891 static int
6893 {
6907 {
6909 /* Extend EXPR according to TYPE_SIGN if the precision isn't a whole
6910 number of bytes. */
6914 {
6921 else
6923 }
6924 else
6929 }
6931 }
6934 /* Subroutine of native_encode_expr. Encode the FIXED_CST
6935 specified by EXPR into the buffer PTR of length LEN bytes.
6936 Return the number of bytes placed in the buffer, or zero
6937 upon failure. */
6939 static int
6941 {
6945 FIXED_VALUE_TYPE value;
6961 }
6964 /* Subroutine of native_encode_expr. Encode the REAL_CST
6965 specified by EXPR into the buffer PTR of length LEN bytes.
6966 Return the number of bytes placed in the buffer, or zero
6967 upon failure. */
6969 static int
6971 {
6977 /* There are always 32 bits in each long, no matter the size of
6978 the hosts long. We handle floating point representations with
6979 up to 192 bits. */
6993 {
6998 {
7005 else
7007 }
7008 else
7009 {
7012 {
7013 /* Reverse bytes within each long, or within the entire float
7014 if it's smaller than a long (for HFmode). */
7017 }
7018 }
7023 }
7025 }
7027 /* Subroutine of native_encode_expr. Encode the COMPLEX_CST
7028 specified by EXPR into the buffer PTR of length LEN bytes.
7029 Return the number of bytes placed in the buffer, or zero
7030 upon failure. */
7032 static int
7034 {
7036 tree part;
7051 }
7054 /* Subroutine of native_encode_expr. Encode the VECTOR_CST
7055 specified by EXPR into the buffer PTR of length LEN bytes.
7056 Return the number of bytes placed in the buffer, or zero
7057 upon failure. */
7059 static int
7061 {
7071 {
7073 {
7076 }
7087 }
7089 }
7092 /* Subroutine of native_encode_expr. Encode the STRING_CST
7093 specified by EXPR into the buffer PTR of length LEN bytes.
7094 Return the number of bytes placed in the buffer, or zero
7095 upon failure. */
7097 static int
7099 {
7101 HOST_WIDE_INT total_bytes;
7115 {
7118 {
7121 }
7124 }
7125 else
7128 }
7131 /* Subroutine of fold_view_convert_expr. Encode the INTEGER_CST,
7132 REAL_CST, COMPLEX_CST or VECTOR_CST specified by EXPR into the
7133 buffer PTR of length LEN bytes. If OFF is not -1 then start
7134 the encoding at byte offset OFF and encode at most LEN bytes.
7135 Return the number of bytes placed in the buffer, or zero upon failure. */
7137 int
7139 {
7140 /* We don't support starting at negative offset and -1 is special. */
7145 {
7166 }
7167 }
7170 /* Subroutine of native_interpret_expr. Interpret the contents of
7171 the buffer PTR of length LEN as an INTEGER_CST of type TYPE.
7172 If the buffer cannot be interpreted, return NULL_TREE. */
7174 static tree
7176 {
7186 }
7189 /* Subroutine of native_interpret_expr. Interpret the contents of
7190 the buffer PTR of length LEN as a FIXED_CST of type TYPE.
7191 If the buffer cannot be interpreted, return NULL_TREE. */
7193 static tree
7195 {
7197 double_int result;
7198 FIXED_VALUE_TYPE fixed_value;
7208 }
7211 /* Subroutine of native_interpret_expr. Interpret the contents of
7212 the buffer PTR of length LEN as a REAL_CST of type TYPE.
7213 If the buffer cannot be interpreted, return NULL_TREE. */
7215 static tree
7217 {
7221 /* There are always 32 bits in each long, no matter the size of
7222 the hosts long. We handle floating point representations with
7223 up to 192 bits. */
7224 REAL_VALUE_TYPE r;
7235 {
7236 /* Both OFFSET and BYTE index within a long;
7237 bitpos indexes the whole float. */
7240 {
7247 else
7249 }
7250 else
7251 {
7254 {
7255 /* Reverse bytes within each long, or within the entire float
7256 if it's smaller than a long (for HFmode). */
7259 }
7260 }
7264 }
7268 }
7271 /* Subroutine of native_interpret_expr. Interpret the contents of
7272 the buffer PTR of length LEN as a COMPLEX_CST of type TYPE.
7273 If the buffer cannot be interpreted, return NULL_TREE. */
7275 static tree
7277 {
7292 }
7295 /* Subroutine of native_interpret_expr. Interpret the contents of
7296 the buffer PTR of length LEN as a VECTOR_CST of type TYPE.
7297 If the buffer cannot be interpreted, return NULL_TREE. */
7299 static tree
7301 {
7314 {
7319 }
7321 }
7324 /* Subroutine of fold_view_convert_expr. Interpret the contents of
7325 the buffer PTR of length LEN as a constant of type TYPE. For
7326 INTEGRAL_TYPE_P we return an INTEGER_CST, for SCALAR_FLOAT_TYPE_P
7327 we return a REAL_CST, etc... If the buffer cannot be interpreted,
7328 return NULL_TREE. */
7330 tree
7332 {
7334 {
7356 }
7357 }
7359 /* Returns true if we can interpret the contents of a native encoding
7360 as TYPE. */
7362 static bool
7364 {
7366 {
7379 }
7380 }
7382 /* Return true iff a constant of type TYPE is accepted by
7383 native_encode_expr. */
7385 bool
7387 {
7389 {
7399 }
7400 }
7402 /* Fold a VIEW_CONVERT_EXPR of a constant expression EXPR to type
7403 TYPE at compile-time. If we're unable to perform the conversion
7404 return NULL_TREE. */
7406 static tree
7408 {
7409 /* We support up to 512-bit values (for V8DFmode). */
7413 /* Check that the host and target are sane. */
7422 }
7424 /* Build an expression for the address of T. Folds away INDIRECT_REF
7425 to avoid confusing the gimplify process. */
7427 tree
7429 {
7430 /* The size of the object is not relevant when talking about its address. */
7435 {
7440 }
7450 {
7455 }
7456 else
7460 }
7462 /* Build an expression for the address of T. */
7464 tree
7466 {
7470 }
7472 /* Fold a unary expression of code CODE and type TYPE with operand
7473 OP0. Return the folded expression if folding is successful.
7474 Otherwise, return NULL_TREE. */
7476 tree
7478 {
7479 tree tem;
7480 tree arg0;
7488 {
7491 {
7492 /* Don't use STRIP_NOPS, because signedness of argument type
7493 matters. */
7495 }
7496 else
7497 {
7498 /* Strip any conversions that don't change the mode. This
7499 is safe for every expression, except for a comparison
7500 expression because its signedness is derived from its
7501 operands.
7503 Note that this is done as an internal manipulation within
7504 the constant folder, in order to find the simplest
7505 representation of the arguments so that their form can be
7506 studied. In any cases, the appropriate type conversions
7507 should be put back in the tree that will get out of the
7508 constant folder. */
7510 }
7513 {
7516 {
7520 }
7521 }
7522 }
7529 {
7536 {
7550 /* If this was a conversion, and all we did was to move into
7551 inside the COND_EXPR, bring it back out. But leave it if
7552 it is a conversion from integer to integer and the
7553 result precision is no wider than a word since such a
7554 conversion is cheap and may be optimized away by combine,
7555 while it couldn't if it were outside the COND_EXPR. Then return
7556 so we don't get into an infinite recursion loop taking the
7557 conversion out and then back in. */
7569 && (INTEGRAL_TYPE_P
7582 }
7583 }
7586 {
7592 CASE_CONVERT:
7596 {
7597 /* If we have (type) (a CMP b) and type is an integral type, return
7598 new expression involving the new type. Canonicalize
7599 (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
7600 non-integral type.
7601 Do not fold the result as that would not simplify further, also
7602 folding again results in recursions. */
7612 }
7614 /* Handle (T *)&A.B.C for A being of type T and B and C
7615 living at offset zero. This occurs frequently in
7616 C++ upcasting and then accessing the base. */
7620 {
7622 tree offset;
7623 machine_mode mode;
7625 tree base
7629 /* If the reference was to a (constant) zero offset, we can use
7630 the address of the base if it has the same base type
7631 as the result type and the pointer type is unqualified. */
7638 }
7642 /* Detect assigning a bitfield. */
7644 && DECL_BIT_FIELD
7646 {
7647 /* Don't leave an assignment inside a conversion
7648 unless assigning a bitfield. */
7650 /* First do the assignment, then return converted constant. */
7655 }
7657 /* Convert (T)(x & c) into (T)x & (T)c, if c is an integer
7658 constants (if x has signed type, the sign bit cannot be set
7659 in c). This folds extension into the BIT_AND_EXPR.
7660 ??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
7661 very likely don't have maximal range for their precision and this
7662 transformation effectively doesn't preserve non-maximal ranges. */
7666 {
7677 <= HOST_BITS_PER_WIDE_INT
7679 {
7683 cst &= HOST_WIDE_INT_M1U
7687 && !flag_syntax_only
7690 {
7694 }
7695 }
7697 {
7702 }
7703 }
7705 /* Convert (T1)(X p+ Y) into ((T1)X p+ Y), for pointer type, when the new
7706 cast (T1)X will fold away. We assume that this happens when X itself
7707 is a cast. */
7711 {
7715 return fold_build_pointer_plus_loc
7717 }
7719 /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
7720 of the same precision, and X is an integer type not narrower than
7721 types T1 or T2, i.e. the cast (T2)X isn't an extension. */
7727 {
7733 }
7735 /* Convert (T1)(X * Y) into (T1)X * (T1)Y if T1 is narrower than the
7736 type of X and Y (integer types only). */
7741 {
7742 /* Be careful not to introduce new overflows. */
7743 tree mult_type;
7746 else
7750 {
7757 }
7758 }
7764 {
7771 }
7782 /* Convert fabs((double)float) into (double)fabsf(float). */
7785 {
7791 targ0));
7792 }
7796 /* Convert ~(X ^ Y) to ~X ^ Y or X ^ ~Y if ~X or ~Y simplify. */
7815 /* Note that the operand of this must be an int
7816 and its values must be 0 or 1.
7817 ("true" is a fixed value perhaps depending on the language,
7818 but we don't handle values other than 1 correctly yet.) */
7825 /* Fold *&X to X if X is an lvalue. */
7827 {
7834 }
7840 }
7843 /* If the operation was a conversion do _not_ mark a resulting constant
7844 with TREE_OVERFLOW if the original constant was not. These conversions
7845 have implementation defined behavior and retaining the TREE_OVERFLOW
7846 flag here would confuse later passes such as VRP. */
7847 tree
7850 {
7859 }
7861 /* Fold a binary bitwise/truth expression of code CODE and type TYPE with
7862 operands OP0 and OP1. LOC is the location of the resulting expression.
7863 ARG0 and ARG1 are the NOP_STRIPed results of OP0 and OP1.
7864 Return the folded expression if folding is successful. Otherwise,
7865 return NULL_TREE. */
7866 static tree
7869 {
7870 tree tem;
7872 /* We only do these simplifications if we are optimizing. */
7876 /* Check for things like (A || B) && (A || C). We can convert this
7877 to A || (B && C). Note that either operator can be any of the four
7878 truth and/or operations and the transformation will still be
7879 valid. Also note that we only care about order for the
7880 ANDIF and ORIF operators. If B contains side effects, this
7881 might change the truth-value of A. */
7888 {
7908 /* This case if tricky because we must either have commutative
7909 operators or else A10 must not have side-effects. */
7915 a01);
7916 }
7918 /* See if we can build a range comparison. */
7924 {
7928 }
7932 {
7936 }
7938 /* Check for the possibility of merging component references. If our
7939 lhs is another similar operation, try to merge its rhs with our
7940 rhs. Then try to merge our lhs and rhs. */
7954 {
7961 /* Transform ((A AND-IF B) AND[-IF] C) into (A AND-IF (B AND C)),
7962 or ((A OR-IF B) OR[-IF] C) into (A OR-IF (B OR C))
7963 We don't want to pack more than two leafs to a non-IF AND/OR
7964 expression.
7965 If tree-code of left-hand operand isn't an AND/OR-IF code and not
7966 equal to IF-CODE, then we don't want to add right-hand operand.
7967 If the inner right-hand side of left-hand operand has
7968 side-effects, or isn't simple, then we can't add to it,
7969 as otherwise we might destroy if-sequence. */
7972 /* Needed for sequence points to handle trappings, and
7973 side-effects. */
7975 {
7977 arg1);
7979 tem);
7980 }
7981 /* Same as abouve but for (A AND[-IF] (B AND-IF C)) -> ((A AND B) AND-IF C),
7982 or (A OR[-IF] (B OR-IF C) -> ((A OR B) OR-IF C). */
7985 /* Needed for sequence points to handle trappings, and
7986 side-effects. */
7988 {
7993 }
7994 /* Transform (A AND-IF B) into (A AND B), or (A OR-IF B)
7995 into (A OR B).
7996 For sequence point consistancy, we need to check for trapping,
7997 and side-effects. */
8001 }
8004 }
8006 /* Helper that tries to canonicalize the comparison ARG0 CODE ARG1
8007 by changing CODE to reduce the magnitude of constants involved in
8008 ARG0 of the comparison.
8009 Returns a canonicalized comparison tree if a simplification was
8010 possible, otherwise returns NULL_TREE.
8011 Set *STRICT_OVERFLOW_P to true if the canonicalization is only
8012 valid if signed overflow is undefined. */
8014 static tree
8018 {
8023 /* Match A +- CST code arg1. We can change this only if overflow
8024 is undefined. */
8027 /* In principle pointers also have undefined overflow behavior,
8028 but that causes problems elsewhere. */
8035 /* Identify the constant in arg0 and its sign. */
8039 /* Overflowed constants and zero will cause problems. */
8044 /* See if we can reduce the magnitude of the constant in
8045 arg0 by changing the comparison code. */
8046 /* A - CST < arg1 -> A - CST-1 <= arg1. */
8050 /* A + CST > arg1 -> A + CST-1 >= arg1. */
8054 /* A + CST <= arg1 -> A + CST-1 < arg1. */
8058 /* A - CST >= arg1 -> A - CST-1 > arg1. */
8062 else
8066 /* Now build the constant reduced in magnitude. But not if that
8067 would produce one outside of its types range. */
8083 }
8085 /* Canonicalize the comparison ARG0 CODE ARG1 with type TYPE with undefined
8086 overflow further. Try to decrease the magnitude of constants involved
8087 by changing LE_EXPR and GE_EXPR to LT_EXPR and GT_EXPR or vice versa
8088 and put sole constants at the second argument position.
8089 Returns the canonicalized tree if changed, otherwise NULL_TREE. */
8091 static tree
8094 {
8095 tree t;
8100 /* Try canonicalization by simplifying arg0. */
8105 {
8109 }
8111 /* Try canonicalization by simplifying arg1 using the swapped
8112 comparison. */
8120 }
8122 /* Return whether BASE + OFFSET + BITPOS may wrap around the address
8123 space. This is used to avoid issuing overflow warnings for
8124 expressions like &p->x which can not wrap. */
8126 static bool
8128 {
8135 wide_int wi_offset;
8141 else
8157 /* We can do slightly better for SIZE if we have an ADDR_EXPR of an
8158 array. */
8160 {
8161 HOST_WIDE_INT base_size;
8166 }
8169 }
8171 /* Return a positive integer when the symbol DECL is known to have
8172 a nonzero address, zero when it's known not to (e.g., it's a weak
8173 symbol), and a negative integer when the symbol is not yet in the
8174 symbol table and so whether or not its address is zero is unknown. */
8175 static int
8177 {
8183 }
8185 /* Subroutine of fold_binary. This routine performs all of the
8186 transformations that are common to the equality/inequality
8187 operators (EQ_EXPR and NE_EXPR) and the ordering operators
8188 (LT_EXPR, LE_EXPR, GE_EXPR and GT_EXPR). Callers other than
8189 fold_binary should call fold_binary. Fold a comparison with
8190 tree code CODE and type TYPE with operands OP0 and OP1. Return
8191 the folded comparison or NULL_TREE. */
8193 static tree
8196 {
8206 /* For comparisons of pointers we can decompose it to a compile time
8207 comparison of the base objects and the offsets into the object.
8208 This requires at least one operand being an ADDR_EXPR or a
8209 POINTER_PLUS_EXPR to do more than the operand_equal_p test below. */
8215 {
8218 machine_mode mode;
8222 /* Get base and offset for the access. Strip ADDR_EXPR for
8223 get_inner_reference, but put it back by stripping INDIRECT_REF
8224 off the base object if possible. indirect_baseN will be true
8225 if baseN is not an address but refers to the object itself. */
8228 {
8229 base0
8235 else
8237 }
8239 {
8243 {
8244 base0
8250 else
8252 }
8255 else
8259 {
8265 {
8268 }
8269 }
8270 }
8274 {
8275 base1
8281 else
8283 }
8285 {
8289 {
8290 base1
8296 else
8298 }
8301 else
8305 {
8311 {
8314 }
8315 }
8316 }
8318 /* If we have equivalent bases we might be able to simplify. */
8322 {
8323 /* We can fold this expression to a constant if the non-constant
8324 offset parts are equal. */
8328 && (equality_code
8329 || (indirect_base0
8333 {
8339 "occur when comparing P +- C1 with "
8341 WARN_STRICT_OVERFLOW_CONDITIONAL);
8344 {
8358 }
8359 }
8360 /* We can simplify the comparison to a comparison of the variable
8361 offset parts if the constant offset parts are equal.
8362 Be careful to use signed sizetype here because otherwise we
8363 mess with array offsets in the wrong way. This is possible
8364 because pointer arithmetic is restricted to retain within an
8365 object and overflow on pointer differences is undefined as of
8366 6.5.6/8 and /9 with respect to the signed ptrdiff_t. */
8368 && (equality_code
8369 || (indirect_base0
8372 {
8373 /* By converting to signed sizetype we cover middle-end pointer
8374 arithmetic which operates on unsigned pointer types of size
8375 type size and ARRAY_REF offsets which are properly sign or
8376 zero extended from their type in case it is narrower than
8377 sizetype. */
8380 else
8384 else
8391 "occur when comparing P +- C1 with "
8393 WARN_STRICT_OVERFLOW_COMPARISON);
8396 }
8397 }
8398 /* For equal offsets we can simplify to a comparison of the
8399 base addresses. */
8401 && (indirect_base0
8403 && (indirect_base1
8408 {
8414 }
8415 /* Comparison between an ordinary (non-weak) symbol and a null
8416 pointer can be eliminated since such symbols must have a non
8417 null address. In C, relational expressions between pointers
8418 to objects and null pointers are undefined. The results
8419 below follow the C++ rules with the additional property that
8420 every object pointer compares greater than a null pointer.
8421 */
8424 /* Avoid folding references to struct members at offset 0 to
8425 prevent tests like '&ptr->firstmember == 0' from getting
8426 eliminated. When ptr is null, although the -> expression
8427 is strictly speaking invalid, GCC retains it as a matter
8428 of QoI. See PR c/44555. */
8431 && indirect_base0
8432 /* The caller guarantees that when one of the arguments is
8433 constant (i.e., null in this case) it is second. */
8435 {
8437 {
8448 }
8449 }
8450 }
8452 /* Transform comparisons of the form X +- C1 CMP Y +- C2 to
8453 X CMP Y +- C2 +- C1 for signed X, Y. This is valid if
8454 the resulting offset is smaller in absolute value than the
8455 original one and has the same sign. */
8464 {
8469 tree cst;
8471 "occur when combining constants around "
8474 /* Put the constant on the side where it doesn't overflow and is
8475 of lower absolute value and of same sign than before. */
8482 {
8485 variable1,
8489 }
8497 {
8503 variable2);
8504 }
8505 }
8511 /* If we are comparing an expression that just has comparisons
8512 of two integer values, arithmetic expressions of those comparisons,
8513 and constants, we can simplify it. There are only three cases
8514 to check: the two values can either be equal, the first can be
8515 greater, or the second can be greater. Fold the expression for
8516 those three values. Since each value must be 0 or 1, we have
8517 eight possibilities, each of which corresponds to the constant 0
8518 or 1 or one of the six possible comparisons.
8520 This handles common cases like (a > b) == 0 but also handles
8521 expressions like ((x > y) - (y > x)) > 0, which supposedly
8522 occur in macroized code. */
8525 {
8530 /* Don't handle degenerate cases here; they should already
8531 have been handled anyway. */
8540 {
8544 /* We can't just pass T to eval_subst in case cval1 or cval2
8545 was the same as ARG1. */
8547 tree high_result
8551 arg1);
8552 tree equal_result
8556 arg1);
8557 tree low_result
8561 arg1);
8563 /* All three of these results should be 0 or 1. Confirm they are.
8564 Then use those values to select the proper code to use. */
8569 {
8570 /* Make a 3-bit mask with the high-order bit being the
8571 value for `>', the next for '=', and the low for '<'. */
8575 {
8577 /* Always false. */
8598 /* Always true. */
8600 }
8603 {
8607 }
8609 }
8610 }
8611 }
8613 /* We can fold X/C1 op C2 where C1 and C2 are integer constants
8614 into a single range test. */
8621 {
8625 }
8628 }
8631 /* Subroutine of fold_binary. Optimize complex multiplications of the
8632 form z * conj(z), as pow(realpart(z),2) + pow(imagpart(z),2). The
8633 argument EXPR represents the expression "z" of type TYPE. */
8635 static tree
8637 {
8642 {
8645 }
8647 {
8650 }
8651 else
8652 {
8656 }
8665 }
8668 /* Helper function for fold_vec_perm. Store elements of VECTOR_CST or
8669 CONSTRUCTOR ARG into array ELTS and return true if successful. */
8671 static bool
8673 {
8677 {
8680 }
8682 {
8688 else
8690 }
8691 else
8697 }
8699 /* Attempt to fold vector permutation of ARG0 and ARG1 vectors using SEL
8700 selector. Return the folded VECTOR_CST or CONSTRUCTOR if successful,
8701 NULL_TREE otherwise. */
8703 static tree
8705 {
8722 {
8726 }
8729 {
8735 }
8736 else
8738 }
8740 /* Try to fold a pointer difference of type TYPE two address expressions of
8741 array references AREF0 and AREF1 using location LOC. Return a
8742 simplified expression for the difference or NULL_TREE. */
8744 static tree
8747 {
8752 /* If the bases are array references as well, recurse. If the bases
8753 are pointer indirections compute the difference of the pointers.
8754 If the bases are equal, we are set. */
8757 && (base_offset
8761 && (base_offset
8767 {
8773 base_offset,
8776 }
8778 }
8780 /* If the real or vector real constant CST of type TYPE has an exact
8781 inverse, return it, else return NULL. */
8783 tree
8785 {
8786 REAL_VALUE_TYPE r;
8788 machine_mode mode;
8792 {
8808 {
8813 }
8819 }
8820 }
8822 /* Mask out the tz least significant bits of X of type TYPE where
8823 tz is the number of trailing zeroes in Y. */
8824 static wide_int
8826 {
8831 }
8833 /* Return true when T is an address and is known to be nonzero.
8834 For floating point we further ensure that T is not denormal.
8835 Similar logic is present in nonzero_address in rtlanal.h.
8837 If the return value is based on the assumption that signed overflow
8838 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
8839 change *STRICT_OVERFLOW_P. */
8841 static bool
8843 {
8847 /* Doing something useful for floating point would need more work. */
8853 {
8856 strict_overflow_p);
8862 strict_overflow_p);
8870 }
8873 {
8876 strict_overflow_p);
8884 strict_overflow_p);
8899 strict_overflow_p);
8903 strict_overflow_p);
8906 {
8918 }
8922 }
8924 }
8926 /* Return true when T is an address and is known to be nonzero.
8927 Handle warnings about undefined signed overflow. */
8929 bool
8931 {
8938 "determining that expression is always "
8940 WARN_STRICT_OVERFLOW_MISC);
8942 }
8944 /* Return true if T is known not to be equal to an integer W. */
8946 bool
8948 {
8950 value_range_type rtype;
8952 {
8961 {
8966 }
8971 /* If T has some known zero bits and W has any of those bits set,
8972 then T is known not to be equal to W. */
8980 }
8981 }
8983 /* Fold a binary expression of code CODE and type TYPE with operands
8984 OP0 and OP1. LOC is the location of the resulting expression.
8985 Return the folded expression if folding is successful. Otherwise,
8986 return NULL_TREE. */
8988 tree
8991 {
9006 /* Strip any conversions that don't change the mode. This is
9007 safe for every expression, except for a comparison expression
9008 because its signedness is derived from its operands. So, in
9009 the latter case, only strip conversions that don't change the
9010 signedness. MIN_EXPR/MAX_EXPR also need signedness of arguments
9011 preserved.
9013 Note that this is done as an internal manipulation within the
9014 constant folder, in order to find the simplest representation
9015 of the arguments so that their form can be studied. In any
9016 cases, the appropriate type conversions should be put back in
9017 the tree that will get out of the constant folder. */
9020 {
9023 }
9024 else
9025 {
9028 }
9030 /* Note that TREE_CONSTANT isn't enough: static var addresses are
9031 constant but we can't do arithmetic on them. */
9033 {
9036 {
9040 }
9041 }
9043 /* If this is a commutative operation, and ARG0 is a constant, move it
9044 to ARG1 to reduce the number of tests below. */
9049 /* Likewise if this is a comparison, and ARG0 is a constant, move it
9050 to ARG1 to reduce the number of tests below. */
9059 /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
9061 First check for cases where an arithmetic operation is applied to a
9062 compound, conditional, or comparison operation. Push the arithmetic
9063 operation inside the compound or conditional to see if any folding
9064 can then be done. Convert comparison to conditional for this purpose.
9065 The also optimizes non-constant cases that used to be done in
9066 expand_expr.
9068 Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
9069 one of the operands is a comparison and the other is a comparison, a
9070 BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
9071 code below would make the expression more complex. Change it to a
9072 TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
9073 TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
9086 {
9090 boolean_type_node,
9098 }
9102 {
9104 {
9109 tem);
9110 }
9112 {
9117 tem);
9118 }
9123 {
9129 }
9134 {
9140 }
9141 }
9144 {
9146 /* MEM[&MEM[p, CST1], CST2] -> MEM[p, CST1 + CST2]. */
9149 {
9155 }
9157 /* MEM[&a.b, CST2] -> MEM[&a, offsetof (a, b) + CST2]. */
9160 {
9161 tree base;
9162 HOST_WIDE_INT coffset;
9171 }
9176 /* INT +p INT -> (PTR)(INT + INT). Stripping types allows for this. */
9182 arg1),
9184 arg0)));
9190 {
9191 /* X + (X / CST) * -CST is X % CST. */
9196 {
9205 cst0));
9206 }
9207 }
9209 /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
9210 one. Make sure the type is not saturating and has the signedness of
9211 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9212 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9219 {
9223 }
9226 {
9227 /* Reassociate (plus (plus (mult) (foo)) (mult)) as
9228 (plus (plus (mult) (mult)) (foo)) so that we can
9229 take advantage of the factoring cases below. */
9238 {
9244 else
9257 parg0),
9259 marg)),
9263 return
9269 parg1)));
9270 }
9271 }
9272 else
9273 {
9274 /* Fold __complex__ ( x, 0 ) + __complex__ ( 0, y )
9275 to __complex__ ( x, y ). This is not the same for SNaNs or
9276 if signed zeros are involved. */
9280 {
9287 {
9291 {
9297 }
9299 {
9305 }
9306 }
9307 }
9315 /* Convert a + (b*c + d*e) into (a + b*c) + d*e.
9316 We associate floats only if the user has specified
9317 -fassociative-math. */
9321 {
9326 {
9327 tree tree0;
9330 }
9331 }
9332 /* Convert (b*c + d*e) + a into b*c + (d*e +a).
9333 We associate floats only if the user has specified
9334 -fassociative-math. */
9338 {
9343 {
9344 tree tree0;
9347 }
9348 }
9349 }
9351 bit_rotate:
9352 /* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
9353 is a rotate of A by C1 bits. */
9354 /* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
9355 is a rotate of A by B bits. */
9356 {
9358 tree rtype;
9367 /* Only create rotates in complete modes. Other cases are not
9368 expanded properly. */
9371 {
9385 {
9389 code0 == LSHIFT_EXPR
9393 }
9395 {
9403 element_precision
9407 return
9410 ? LROTATE_EXPR
9415 }
9417 {
9425 element_precision
9429 return fold_convert_loc
9432 ? LROTATE_EXPR
9436 }
9437 }
9438 }
9440 associate:
9441 /* In most languages, can't associate operations on floats through
9442 parentheses. Rather than remember where the parentheses were, we
9443 don't associate floats at all, unless the user has specified
9444 -fassociative-math.
9445 And, we need to make sure type is not saturating. */
9449 {
9455 /* Split both trees into variables, constants, and literals. Then
9456 associate each group together, the constants with literals,
9457 then the result with variables. This increases the chances of
9458 literals being recombined later and of generating relocatable
9459 expressions for the sum of a constant and literal. */
9465 /* Recombine MINUS_EXPR operands by using PLUS_EXPR. */
9469 /* With undefined overflow prefer doing association in a type
9470 which wraps on overflow, if that is one of the operand types. */
9473 {
9481 }
9483 /* With undefined overflow we can only associate constants with one
9484 variable, and constants whose association doesn't overflow. */
9487 {
9489 {
9495 {
9498 }
9505 {
9508 }
9514 /* The only case we can still associate with two variables
9515 is if they cancel out. */
9519 }
9520 }
9522 /* Only do something if we found more than two objects. Otherwise,
9523 nothing has changed and we risk infinite recursion. */
9529 {
9541 /* Preserve the MINUS_EXPR if the negative part of the literal is
9542 greater than the positive part. Otherwise, the multiplicative
9543 folding code (i.e extract_muldiv) may be fooled in case
9544 unsigned constants are subtracted, like in the following
9545 example: ((X*2 + 4) - 8U)/2. */
9547 {
9551 {
9555 }
9556 else
9557 {
9561 }
9562 }
9564 /* Don't introduce overflows through reassociation. */
9571 {
9573 return
9577 else
9578 {
9581 return
9585 }
9586 }
9589 return
9592 }
9593 }
9598 /* (-A) - B -> (-B) - A where B is easily negated and we can swap. */
9606 /* Fold __complex__ ( x, 0 ) - __complex__ ( 0, y ) to
9607 __complex__ ( x, -y ). This is not the same for SNaNs or if
9608 signed zeros are involved. */
9612 {
9619 {
9623 {
9625 arg1r ? arg1r
9630 }
9632 {
9636 arg1i ? arg1i
9639 }
9640 }
9641 }
9643 /* A - B -> A + (-B) if B is easily negatable. */
9647 /* Avoid this transformation if B is a positive REAL_CST. */
9655 /* Fold &a[i] - &a[j] to i-j. */
9660 {
9666 }
9669 && flag_unsafe_math_optimizations
9675 /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
9676 one. Make sure the type is not saturating and has the signedness of
9677 the stripped operands, as fold_plusminus_mult_expr will re-associate.
9678 ??? The latter condition should use TYPE_OVERFLOW_* flags instead. */
9685 {
9689 }
9695 {
9696 /* Transform x * -C into -x * C if x is easily negatable. */
9710 {
9713 "occur when simplifying "
9715 WARN_STRICT_OVERFLOW_MISC);
9717 }
9719 /* Optimize z * conj(z) for integer complex numbers. */
9726 }
9727 else
9728 {
9729 /* Fold z * +-I to __complex__ (-+__imag z, +-__real z).
9730 This is not the same for NaNs or if signed zeros are
9731 involved. */
9737 {
9740 return
9746 return
9751 }
9753 /* Optimize z * conj(z) for floating point complex numbers.
9754 Guarded by flag_unsafe_math_optimizations as non-finite
9755 imaginary components don't produce scalar results. */
9764 }
9768 /* Canonicalize (X & C1) | C2. */
9772 {
9777 /* If (C1&C2) == C1, then (X&C1)|C2 becomes (X,C2). */
9785 /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2. */
9790 /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
9791 unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
9792 mode which allows further optimizations. */
9797 {
9801 {
9804 }
9805 }
9812 c3)),
9813 arg1);
9814 }
9816 /* See if this can be simplified into a rotate first. If that
9817 is unsuccessful continue in the association code. */
9821 /* Fold (X & 1) ^ 1 as (X & 1) == 0. */
9829 /* See if this can be simplified into a rotate first. If that
9830 is unsuccessful continue in the association code. */
9834 /* Fold (X ^ 1) & 1 as (X & 1) == 0. */
9839 {
9840 tree tem2;
9847 }
9848 /* Fold ~X & 1 as (X & 1) == 0. */
9852 {
9853 tree tem2;
9860 }
9861 /* Fold !X & 1 as X == 0. */
9864 {
9868 }
9870 /* Fold (X * Y) & -(1 << CST) to X * Y if Y is a constant
9871 multiple of 1 << CST. */
9873 {
9880 }
9882 /* Fold (X * CST1) & CST2 to zero if we can, or drop known zero
9883 bits from CST2. */
9887 {
9895 {
9896 /* Avoid the transform if arg1 is a mask of some
9897 mode which allows further optimizations. */
9904 }
9905 }
9907 /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
9908 ((A & N) + B) & M -> (A + B) & M
9909 Similarly if (N & M) == 0,
9910 ((A | N) + B) & M -> (A + B) & M
9911 and for - instead of + (or unary - instead of +)
9912 and/or ^ instead of |.
9913 If B is constant and (B & M) == 0, fold into A & M. */
9915 {
9924 {
9927 wide_int cst0;
9929 /* Now we know that arg0 is (C + D) or (C - D) or
9930 -C and arg1 (M) is == (1LL << cst) - 1.
9931 Store C into PMOP[0] and D into PMOP[1]. */
9935 {
9938 }
9945 {
9955 {
9958 }
9961 /* If C or D is of the form (A & N) where
9962 (N & M) == M, or of the form (A | N) or
9963 (A ^ N) where (N & M) == 0, replace it with A. */
9967 /* If C or D is a N where (N & M) == 0, it can be
9968 omitted (assumed 0). */
9976 }
9978 /* Only build anything new if we optimized one or both arguments
9979 above. */
9983 {
9986 {
9987 /* Perform the operations in a type that has defined
9988 overflow behavior. */
9994 }
9999 {
10007 else
10009 }
10012 else
10015 /* TEM is now the new binary +, - or unary - replacement. */
10019 }
10020 }
10021 }
10023 /* Simplify ((int)c & 0377) into (int)c, if c is unsigned char. */
10026 {
10031 return
10033 }
10038 /* Don't touch a floating-point divide by zero unless the mode
10039 of the constant can represent infinity. */
10045 /* (-A) / (-B) -> A / B */
10057 /* Fall through */
10060 /* Simplify A / (B << N) where A and B are positive and B is
10061 a power of 2, to A >> (N + log2(B)). */
10066 {
10069 {
10077 WARN_STRICT_OVERFLOW_MISC);
10083 }
10084 }
10086 /* Fall through */
10094 /* Convert -A / -B to A / B when the type is signed and overflow is
10095 undefined. */
10099 {
10102 "when distributing negation across "
10104 WARN_STRICT_OVERFLOW_MISC);
10109 }
10113 {
10116 "when distributing negation across "
10118 WARN_STRICT_OVERFLOW_MISC);
10123 }
10125 /* If arg0 is a multiple of arg1, then rewrite to the fastest div
10126 operation, EXACT_DIV_EXPR.
10128 Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
10129 At one time others generated faster code, it's not clear if they do
10130 after the last round to changes to the DIV code in expmed.c. */
10141 {
10145 WARN_STRICT_OVERFLOW_MISC);
10147 }
10159 {
10163 WARN_STRICT_OVERFLOW_MISC);
10165 }
10173 /* Since negative shift count is not well-defined,
10174 don't try to compute it in the compiler. */
10180 /* If we have a rotate of a bit operation with the rotate count and
10181 the second operand of the bit operation both constant,
10182 permute the two operations. */
10188 {
10196 }
10198 /* Two consecutive rotates adding up to the some integer
10199 multiple of the precision of the type can be ignored. */
10214 /* Note that the operands of this must be ints
10215 and their values must be 0 or 1.
10216 ("true" is a fixed value perhaps depending on the language.) */
10217 /* If first arg is constant zero, return it. */
10220 /* FALLTHRU */
10222 /* If either arg is constant true, drop it. */
10226 /* Preserve sequence points. */
10229 /* If second arg is constant zero, result is zero, but first arg
10230 must be evaluated. */
10233 /* Likewise for first arg, but note that only the TRUTH_AND_EXPR
10234 case will be handled here. */
10238 /* !X && X is always false. */
10242 /* X && !X is always false. */
10247 /* A < X && A + 1 > Y ==> A < X && A >= Y. Normally A + 1 > Y
10248 means A >= Y && A != MAX, but in this case we know that
10249 A < X <= MAX. */
10253 {
10261 }
10270 /* Note that the operands of this must be ints
10271 and their values must be 0 or true.
10272 ("true" is a fixed value perhaps depending on the language.) */
10273 /* If first arg is constant true, return it. */
10276 /* FALLTHRU */
10278 /* If either arg is constant zero, drop it. */
10282 /* Preserve sequence points. */
10285 /* If second arg is constant true, result is true, but we must
10286 evaluate first arg. */
10289 /* Likewise for first arg, but note this only occurs here for
10290 TRUTH_OR_EXPR. */
10294 /* !X || X is always true. */
10298 /* X || !X is always true. */
10303 /* (X && !Y) || (!X && Y) is X ^ Y */
10306 {
10323 }
10332 /* If the second arg is constant zero, drop it. */
10335 /* If the second arg is constant true, this is a logical inversion. */
10337 {
10340 }
10341 /* Identical arguments cancel to zero. */
10345 /* !X ^ X is always true. */
10350 /* X ^ !X is always true. */
10366 /* bool_var != 1 becomes !bool_var. */
10373 /* bool_var == 0 becomes !bool_var. */
10380 /* !exp != 0 becomes !exp */
10385 /* Transform comparisons of the form X +- Y CMP X to Y CMP 0. */
10394 {
10400 }
10402 /* Transform comparisons of the form X CMP X +- Y to Y CMP 0. */
10411 {
10417 }
10419 /* Transform comparisons of the form C - X CMP X if C % 2 == 1. */
10427 code == NE_EXPR
10431 /* Transform comparisons of the form X CMP C - X if C % 2 == 1. */
10439 code == NE_EXPR
10443 /* If this is an EQ or NE comparison with zero and ARG0 is
10444 (1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
10445 two operations, but the latter can be done in one less insn
10446 on machines that have only two-operand insns or on which a
10447 constant cannot be the first operand. */
10450 {
10455 {
10462 arg1);
10463 }
10466 {
10473 arg1);
10474 }
10475 }
10477 /* If this is an NE or EQ comparison of zero against the result of a
10478 signed MOD operation whose second operand is a power of 2, make
10479 the MOD operation unsigned since it is simpler and equivalent. */
10487 {
10497 }
10499 /* Fold ((X >> C1) & C2) == 0 and ((X >> C1) & C2) != 0 where
10500 C1 is a valid shift constant, and C2 is a power of two, i.e.
10501 a single bit. */
10505 == INTEGER_CST
10508 {
10513 /* Check for a valid shift count. */
10515 {
10519 /* If (C2 << C1) doesn't overflow, then ((X >> C1) & C2) != 0
10520 can be rewritten as (X & (C2 << C1)) != 0. */
10522 {
10527 }
10528 /* Otherwise, for signed (arithmetic) shifts,
10529 ((X >> C1) & C2) != 0 is rewritten as X < 0, and
10530 ((X >> C1) & C2) == 0 is rewritten as X >= 0. */
10534 /* Otherwise, of unsigned (logical) shifts,
10535 ((X >> C1) & C2) != 0 is rewritten as (X,false), and
10536 ((X >> C1) & C2) == 0 is rewritten as (X,true). */
10537 else
10541 arg000);
10542 }
10543 }
10545 /* If we have (A & C) == D where D & ~C != 0, convert this into 0.
10546 Similarly for NE_EXPR. */
10550 {
10554 tree dandnotc
10557 notc);
10561 }
10563 /* If this is a comparison of a field, we may be able to simplify it. */
10566 /* Handle the constant case even without -O
10567 to make sure the warnings are given. */
10569 {
10573 }
10575 /* Optimize comparisons of strlen vs zero to a compare of the
10576 first character of the string vs zero. To wit,
10577 strlen(ptr) == 0 => *ptr == 0
10578 strlen(ptr) != 0 => *ptr != 0
10579 Other cases should reduce to one of these two (or a constant)
10580 due to the return value of strlen being unsigned. */
10583 {
10591 {
10596 }
10597 }
10599 /* Fold (X >> C) != 0 into X < 0 if C is one less than the width
10600 of X. Similarly fold (X >> C) == 0 into X >= 0. */
10604 {
10609 {
10611 {
10614 }
10617 }
10618 }
10620 /* Fold (~X & C) == 0 into (X & C) != 0 and (~X & C) != 0 into
10621 (X & C) == 0 when C is a single bit. */
10626 {
10633 arg1));
10634 }
10636 /* Fold ((X & C) ^ C) eq/ne 0 into (X & C) ne/eq 0, when the
10637 constant C is a power of two, i.e. a single bit. */
10644 {
10648 }
10650 /* Likewise, fold ((X ^ C) & C) eq/ne 0 into (X & C) ne/eq 0,
10651 when is C is a power of two, i.e. a single bit. */
10658 {
10664 }
10668 {
10671 }
10673 /* Fold (X & C) op (Y & C) as (X ^ Y) & C op 0", and symmetries. */
10676 {
10689 arg01),
10698 arg01),
10707 arg00),
10716 arg00),
10718 }
10722 {
10729 /* Optimize (X ^ Z) op (Y ^ Z) as X op Y, and symmetries.
10730 operand_equal_p guarantees no side-effects so we don't need
10731 to use omit_one_operand on Z. */
10735 arg10));
10739 arg11));
10743 arg10));
10747 arg11));
10749 /* Optimize (X ^ C1) op (Y ^ C2) as (X ^ (C1 ^ C2)) op Y. */
10752 {
10758 }
10759 }
10761 /* Attempt to simplify equality/inequality comparisons of complex
10762 values. Only lower the comparison if the result is known or
10763 can be simplified to a single scalar comparison. */
10768 {
10773 {
10776 }
10777 else
10778 {
10781 }
10784 {
10787 }
10788 else
10789 {
10792 }
10796 {
10798 {
10803 }
10804 else
10805 {
10810 }
10811 }
10815 {
10817 {
10822 }
10823 else
10824 {
10829 }
10830 }
10831 }
10843 /* Transform comparisons of the form X +- C CMP X. */
10850 {
10857 else
10860 /* (X - c) > X becomes false. */
10864 {
10868 "occur when assuming that (X - c) > X "
10870 WARN_STRICT_OVERFLOW_ALL);
10872 }
10874 /* Likewise (X + c) < X becomes false. */
10878 {
10882 "occur when assuming that "
10884 WARN_STRICT_OVERFLOW_ALL);
10886 }
10888 /* Convert (X - c) <= X to true. */
10893 {
10897 "occur when assuming that "
10899 WARN_STRICT_OVERFLOW_ALL);
10901 }
10903 /* Convert (X + c) >= X to true. */
10908 {
10912 "occur when assuming that "
10914 WARN_STRICT_OVERFLOW_ALL);
10916 }
10919 {
10920 /* Convert X + c > X and X - c < X to true for integers. */
10924 {
10927 "not occur when assuming that "
10929 WARN_STRICT_OVERFLOW_ALL);
10931 }
10936 {
10939 "not occur when assuming that "
10941 WARN_STRICT_OVERFLOW_ALL);
10943 }
10945 /* Convert X + c <= X and X - c >= X to false for integers. */
10949 {
10952 "not occur when assuming that "
10954 WARN_STRICT_OVERFLOW_ALL);
10956 }
10961 {
10964 "not occur when assuming that "
10966 WARN_STRICT_OVERFLOW_ALL);
10968 }
10969 }
10970 }
10972 /* If we are comparing an ABS_EXPR with a constant, we can
10973 convert all the cases into explicit comparisons, but they may
10974 well not be faster than doing the ABS and one comparison.
10975 But ABS (X) <= C is a range comparison, which becomes a subtraction
10976 and a comparison, and is probably faster. */
10990 /* Convert ABS_EXPR<x> >= 0 to true. */
10997 {
11000 "when simplifying comparison of "
11002 WARN_STRICT_OVERFLOW_CONDITIONAL);
11005 arg0);
11006 }
11008 /* Convert ABS_EXPR<x> < 0 to false. */
11013 {
11016 "when simplifying comparison of "
11018 WARN_STRICT_OVERFLOW_CONDITIONAL);
11021 arg0);
11022 }
11024 /* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
11025 and similarly for >= into !=. */
11035 /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing,
11036 otherwise Y might be >= # of bits in X's type and thus e.g.
11037 (unsigned char) (1 << Y) for Y 15 might be 0.
11038 If the cast is widening, then 1 << Y should have unsigned type,
11039 otherwise if Y is number of bits in the signed shift type minus 1,
11040 we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y
11041 31 might be 0xffffffff80000000. */
11052 {
11058 }
11070 /* Fold (double)float1 CMP (double)float2 into float1 CMP float2. */
11071 {
11083 }
11088 /* When pedantic, a compound expression can be neither an lvalue
11089 nor an integer constant expression. */
11092 /* Don't let (0, 0) be null pointer constant. */
11098 /* An ASSERT_EXPR should never be passed to fold_binary. */
11104 }
11106 /* Callback for walk_tree, looking for LABEL_EXPR. Return *TP if it is
11107 a LABEL_EXPR; otherwise return NULL_TREE. Do not check the subtrees
11108 of GOTO_EXPR. */
11110 static tree
11112 {
11114 {
11121 /* fall through */
11125 }
11126 }
11128 /* Return whether the sub-tree ST contains a label which is accessible from
11129 outside the sub-tree. */
11131 static bool
11133 {
11134 return
11136 }
11138 /* Fold a ternary expression of code CODE and type TYPE with operands
11139 OP0, OP1, and OP2. Return the folded expression if folding is
11140 successful. Otherwise, return NULL_TREE. */
11142 tree
11145 {
11146 tree tem;
11153 /* If this is a commutative operation, and OP0 is a constant, move it
11154 to OP1 to reduce the number of tests below. */
11163 /* Strip any conversions that don't change the mode. This is safe
11164 for every expression, except for a comparison expression because
11165 its signedness is derived from its operands. So, in the latter
11166 case, only strip conversions that don't change the signedness.
11168 Note that this is done as an internal manipulation within the
11169 constant folder, in order to find the simplest representation of
11170 the arguments so that their form can be studied. In any cases,
11171 the appropriate type conversions should be put back in the tree
11172 that will get out of the constant folder. */
11174 {
11177 }
11180 {
11183 }
11186 {
11189 }
11192 {
11196 {
11202 }
11207 /* Pedantic ANSI C says that a conditional expression is never an lvalue,
11208 so all simple results must be passed through pedantic_non_lvalue. */
11210 {
11213 /* Only optimize constant conditions when the selected branch
11214 has the same type as the COND_EXPR. This avoids optimizing
11215 away "c ? x : throw", where the throw has a void type.
11216 Avoid throwing away that operand which contains label. */
11223 }
11225 {
11230 {
11235 {
11243 }
11247 }
11248 }
11250 /* If we have A op B ? A : C, we may be able to convert this to a
11251 simpler expression, depending on the operation and the values
11252 of B and C. Signed zeros prevent all of these transformations,
11253 for reasons given above each one.
11255 Also try swapping the arguments and inverting the conditional. */
11260 {
11264 }
11268 op2,
11271 {
11275 {
11279 }
11280 }
11282 /* If the second operand is simpler than the third, swap them
11283 since that produces better jump optimization results. */
11286 {
11288 /* See if this can be inverted. If it can't, possibly because
11289 it was a floating-point inequality comparison, don't do
11290 anything. */
11294 }
11296 /* Convert A ? 1 : 0 to simply A. */
11301 /* If we try to convert OP0 to our type, the
11302 call to fold will try to move the conversion inside
11303 a COND, which will recurse. In that case, the COND_EXPR
11304 is probably the best choice, so leave it alone. */
11308 /* Convert A ? 0 : 1 to !A. This prefers the use of NOT_EXPR
11309 over COND_EXPR in cases such as floating point comparisons. */
11318 arg0)));
11320 /* A < 0 ? <sign bit of A> : 0 is simply (A & <sign bit of A>). */
11325 {
11326 /* sign_bit_p looks through both zero and sign extensions,
11327 but for this optimization only sign extensions are
11328 usable. */
11331 {
11334 {
11337 }
11339 }
11340 /* sign_bit_p only checks ARG1 bits within A's precision.
11341 If <sign bit of A> has wider type than A, bits outside
11342 of A's precision in <sign bit of A> need to be checked.
11343 If they are all 0, this optimization needs to be done
11344 in unsigned A's type, if they are all 1 in signed A's type,
11345 otherwise this can't be done. */
11351 {
11353 tree tem_type;
11366 {
11369 }
11371 {
11374 }
11375 else
11377 }
11380 return
11386 arg1)));
11387 }
11389 /* (A >> N) & 1 ? (1 << N) : 0 is simply A & (1 << N). A & 1 was
11390 already handled above. */
11395 {
11404 }
11406 /* A & N ? N : 0 is simply A & N if N is a power of two. This
11407 is probably obsolete because the first operand should be a
11408 truth value (that's why we have the two cases above), but let's
11409 leave it in until we can confirm this for all front-ends. */
11421 /* Disable the transformations below for vectors, since
11422 fold_binary_op_with_conditional_arg may undo them immediately,
11423 yielding an infinite loop. */
11427 /* Convert A ? B : 0 into A && B if A and B are truth values. */
11436 /* Convert A ? B : 1 into !A || B if A and B are truth values. */
11441 {
11443 /* Only perform transformation if ARG0 is easily inverted. */
11447 ? BIT_IOR_EXPR
11450 arg1);
11451 }
11453 /* Convert A ? 0 : B into !A && B if A and B are truth values. */
11458 {
11460 /* Only perform transformation if ARG0 is easily inverted. */
11466 op2);
11467 }
11469 /* Convert A ? 1 : B into A || B if A and B are truth values. */
11481 /* CALL_EXPRs used to be ternary exprs. Catch any mistaken uses
11482 of fold_ternary on them. */
11490 {
11500 {
11505 {
11513 }
11514 }
11515 }
11517 /* On constants we can use native encode/interpret to constant
11518 fold (nearly) all BIT_FIELD_REFs. */
11522 {
11525 /* Limit us to a reasonable amount of work. To relax the
11526 other limitations we need bit-shifting of the buffer
11527 and rounding up the size. */
11531 {
11533 unsigned HOST_WIDE_INT len
11538 {
11543 }
11544 }
11545 }
11550 /* For integers we can decompose the FMA if possible. */
11562 {
11578 {
11583 /* Make sure that the perm value is in an acceptable
11584 range. */
11593 else
11598 }
11601 {
11606 }
11611 {
11616 }
11622 {
11626 }
11631 /* Some targets are deficient and fail to expand a single
11632 argument permutation while still allowing an equivalent
11633 2-argument version. */
11637 {
11640 }
11643 {
11650 }
11654 }
11658 /* Perform (partial) constant folding of BIT_INSERT_EXPR. */
11661 {
11667 wide_int tem2
11671 }
11676 {
11678 unsigned HOST_WIDE_INT elsize
11681 {
11685 else
11686 {
11692 }
11693 }
11694 }
11700 }
11702 /* Gets the element ACCESS_INDEX from CTOR, which must be a CONSTRUCTOR
11703 of an array (or vector). */
11705 tree
11707 {
11712 {
11715 {
11716 /* Static constructors for variably sized objects makes no sense. */
11720 }
11721 }
11732 offset_int max_index;
11737 {
11738 /* Array constructor might explicitly set index, or specify a range,
11739 or leave index NULL meaning that it is next index after previous
11740 one. */
11742 {
11745 else
11746 {
11750 }
11751 }
11752 else
11753 {
11759 }
11761 /* Do we have match? */
11765 }
11767 }
11769 /* Perform constant folding and related simplification of EXPR.
11770 The related simplifications include x*1 => x, x*0 => 0, etc.,
11771 and application of the associative law.
11772 NOP_EXPR conversions may be removed freely (as long as we
11773 are careful not to change the type of the overall expression).
11774 We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
11775 but we can constant-fold them if they have constant operands. */
11777 #ifdef ENABLE_FOLD_CHECKING
11778 # define fold(x) fold_1 (x)
11780 static
11781 #endif
11782 tree
11784 {
11788 tree tem;
11791 /* Return right away if a constant. */
11795 /* CALL_EXPR-like objects with variable numbers of operands are
11796 treated specially. */
11798 {
11800 {
11803 }
11805 }
11808 {
11813 {
11831 }
11832 }
11835 {
11837 {
11844 {
11849 }
11852 }
11854 /* Return a VECTOR_CST if possible. */
11856 {
11862 tree val;
11868 }
11876 }
11878 #ifdef ENABLE_FOLD_CHECKING
11879 #undef fold
11886 /* When --enable-checking=fold, compute a digest of expr before
11887 and after actual fold call to see if fold did not accidentally
11888 change original expr. */
11890 tree
11892 {
11893 tree ret;
11913 }
11915 void
11917 {
11928 }
11930 static void
11932 {
11934 }
11936 static void
11939 {
11945 recursive_label:
11955 {
11956 /* Allow DECL_ASSEMBLER_NAME and symtab_node to be modified. */
11961 }
11969 {
11970 /* Allow these fields to be modified. */
11971 tree tmp;
11980 {
11983 }
11984 }
11995 {
11998 {
12013 }
12017 {
12030 }
12047 {
12053 }
12056 {
12058 {
12061 }
12063 }
12074 {
12077 }
12087 }
12088 }
12090 /* Helper function for outputting the checksum of a tree T. When
12091 debugging with gdb, you can "define mynext" to be "next" followed
12092 by "call debug_fold_checksum (op0)", then just trace down till the
12093 outputs differ. */
12095 DEBUG_FUNCTION void
12097 {
12112 }
12114 #endif
12116 /* Fold a unary tree expression with code CODE of type TYPE with an
12117 operand OP0. LOC is the location of the resulting expression.
12118 Return a folded expression if successful. Otherwise, return a tree
12119 expression with code CODE of type TYPE with an operand OP0. */
12121 tree
12124 {
12125 tree tem;
12126 #ifdef ENABLE_FOLD_CHECKING
12135 #endif
12141 #ifdef ENABLE_FOLD_CHECKING
12148 #endif
12150 }
12152 /* Fold a binary tree expression with code CODE of type TYPE with
12153 operands OP0 and OP1. LOC is the location of the resulting
12154 expression. Return a folded expression if successful. Otherwise,
12155 return a tree expression with code CODE of type TYPE with operands
12156 OP0 and OP1. */
12158 tree
12161 MEM_STAT_DECL)
12162 {
12163 tree tem;
12164 #ifdef ENABLE_FOLD_CHECKING
12181 #endif
12187 #ifdef ENABLE_FOLD_CHECKING
12202 #endif
12204 }
12206 /* Fold a ternary tree expression with code CODE of type TYPE with
12207 operands OP0, OP1, and OP2. Return a folded expression if
12208 successful. Otherwise, return a tree expression with code CODE of
12209 type TYPE with operands OP0, OP1, and OP2. */
12211 tree
12214 {
12215 tree tem;
12216 #ifdef ENABLE_FOLD_CHECKING
12240 #endif
12247 #ifdef ENABLE_FOLD_CHECKING
12270 #endif
12272 }
12274 /* Fold a CALL_EXPR expression of type TYPE with operands FN and NARGS
12275 arguments in ARGARRAY, and a null static chain.
12276 Return a folded expression if successful. Otherwise, return a CALL_EXPR
12277 of type TYPE from the given operands as constructed by build_call_array. */
12279 tree
12282 {
12283 tree tem;
12284 #ifdef ENABLE_FOLD_CHECKING
12303 #endif
12309 #ifdef ENABLE_FOLD_CHECKING
12325 #endif
12327 }
12329 /* Perform constant folding and related simplification of initializer
12330 expression EXPR. These behave identically to "fold_buildN" but ignore
12331 potential run-time traps and exceptions that fold must preserve. */
12333 #define START_FOLD_INIT \
12334 int saved_signaling_nans = flag_signaling_nans;\
12335 int saved_trapping_math = flag_trapping_math;\
12336 int saved_rounding_math = flag_rounding_math;\
12337 int saved_trapv = flag_trapv;\
12338 int saved_folding_initializer = folding_initializer;\
12339 flag_signaling_nans = 0;\
12340 flag_trapping_math = 0;\
12341 flag_rounding_math = 0;\
12342 flag_trapv = 0;\
12343 folding_initializer = 1;
12345 #define END_FOLD_INIT \
12346 flag_signaling_nans = saved_signaling_nans;\
12347 flag_trapping_math = saved_trapping_math;\
12348 flag_rounding_math = saved_rounding_math;\
12349 flag_trapv = saved_trapv;\
12350 folding_initializer = saved_folding_initializer;
12352 tree
12355 {
12356 tree result;
12357 START_FOLD_INIT;
12361 END_FOLD_INIT;
12363 }
12365 tree
12368 {
12369 tree result;
12370 START_FOLD_INIT;
12374 END_FOLD_INIT;
12376 }
12378 tree
12381 {
12382 tree result;
12383 START_FOLD_INIT;
12387 END_FOLD_INIT;
12389 }
12391 #undef START_FOLD_INIT
12392 #undef END_FOLD_INIT
12394 /* Determine if first argument is a multiple of second argument. Return 0 if
12395 it is not, or we cannot easily determined it to be.
12397 An example of the sort of thing we care about (at this point; this routine
12398 could surely be made more general, and expanded to do what the *_DIV_EXPR's
12399 fold cases do now) is discovering that
12401 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12403 is a multiple of
12405 SAVE_EXPR (J * 8)
12407 when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
12409 This code also handles discovering that
12411 SAVE_EXPR (I) * SAVE_EXPR (J * 8)
12413 is a multiple of 8 so we don't have to worry about dealing with a
12414 possible remainder.
12416 Note that we *look* inside a SAVE_EXPR only to determine how it was
12417 calculated; it is not safe for fold to do much of anything else with the
12418 internals of a SAVE_EXPR, since it cannot know when it will be evaluated
12419 at run time. For example, the latter example above *cannot* be implemented
12420 as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
12421 evaluation time of the original SAVE_EXPR is not necessarily the same at
12422 the time the new expression is evaluated. The only optimization of this
12423 sort that would be valid is changing
12425 SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
12427 divided by 8 to
12429 SAVE_EXPR (I) * SAVE_EXPR (J)
12431 (where the same SAVE_EXPR (J) is used in the original and the
12432 transformed version). */
12434 int
12436 {
12447 {
12449 /* Bitwise and provides a power of two multiple. If the mask is
12450 a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
12453 /* FALLTHRU */
12460 /* It is impossible to prove if op0 - op1 is multiple of bottom
12461 precisely, so be conservative here checking if both op0 and op1
12462 are multiple of bottom. Note we check the second operand first
12463 since it's usually simpler. */
12468 /* The same as MINUS_EXPR, but handle cases like op0 + 0xfffffffd
12469 as op0 - 3 if the expression has unsigned type. For example,
12470 (X / 3) + 0xfffffffd is multiple of 3, but 0xfffffffd is not. */
12480 {
12482 /* const_binop may not detect overflow correctly,
12483 so check for it explicitly here. */
12487 size_one_node,
12488 op1)))
12491 }
12495 /* Can't handle conversions from non-integral or wider integral type. */
12501 /* fall through */
12518 SIGNED);
12524 {
12527 /* Check for special cases to see if top is defined as multiple
12528 of bottom:
12530 top = (X & ~(bottom - 1) ; bottom is power of 2
12532 or
12534 Y = X % bottom
12535 top = X - Y. */
12554 }
12556 /* fall through */
12560 }
12561 }
12563 #define tree_expr_nonnegative_warnv_p(X, Y) \
12566 #define RECURSE(X) \
12567 ((tree_expr_nonnegative_warnv_p) (X, strict_overflow_p, depth + 1))
12569 /* Return true if CODE or TYPE is known to be non-negative. */
12571 static bool
12573 {
12576 /* Truth values evaluate to 0 or 1, which is nonnegative unless we
12577 have a signed:1 type (where the value is -1 and 0). */
12580 }
12582 /* Return true if (CODE OP0) is known to be non-negative. If the return
12583 value is based on the assumption that signed overflow is undefined,
12584 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12585 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12587 bool
12590 {
12595 {
12597 /* We can't return 1 if flag_wrapv is set because
12598 ABS_EXPR<INT_MIN> = INT_MIN. */
12602 {
12605 }
12613 CASE_CONVERT:
12614 {
12619 {
12623 {
12627 }
12628 }
12630 {
12636 }
12637 }
12642 }
12644 /* We don't know sign of `t', so be conservative and return false. */
12646 }
12648 /* Return true if (CODE OP0 OP1) is known to be non-negative. If the return
12649 value is based on the assumption that signed overflow is undefined,
12650 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12651 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12653 bool
12657 {
12662 {
12668 /* zero_extend(x) + zero_extend(y) is non-negative if x and y are
12669 both unsigned and at least 2 bits shorter than the result. */
12673 {
12678 {
12682 }
12683 }
12688 {
12689 /* x * x is always non-negative for floating point x
12690 or without overflow. */
12693 {
12698 }
12699 }
12701 /* zero_extend(x) * zero_extend(y) is non-negative if x and y are
12702 both unsigned and their total bits is shorter than the result. */
12706 {
12725 {
12735 }
12736 }
12763 }
12765 /* We don't know sign of `t', so be conservative and return false. */
12767 }
12769 /* Return true if T is known to be non-negative. If the return
12770 value is based on the assumption that signed overflow is undefined,
12771 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12772 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12774 bool
12776 {
12781 {
12795 /* Limit the depth of recursion to avoid quadratic behavior.
12796 This is expected to catch almost all occurrences in practice.
12797 If this code misses important cases that unbounded recursion
12798 would not, passes that need this information could be revised
12799 to provide it through dataflow propagation. */
12807 }
12808 }
12810 /* Return true if T is known to be non-negative. If the return
12811 value is based on the assumption that signed overflow is undefined,
12812 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12813 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12815 bool
12818 {
12820 {
12821 CASE_CFN_ACOS:
12822 CASE_CFN_ACOSH:
12823 CASE_CFN_CABS:
12824 CASE_CFN_COSH:
12825 CASE_CFN_ERFC:
12826 CASE_CFN_EXP:
12827 CASE_CFN_EXP10:
12828 CASE_CFN_EXP2:
12829 CASE_CFN_FABS:
12830 CASE_CFN_FDIM:
12831 CASE_CFN_HYPOT:
12832 CASE_CFN_POW10:
12833 CASE_CFN_FFS:
12834 CASE_CFN_PARITY:
12835 CASE_CFN_POPCOUNT:
12836 CASE_CFN_CLZ:
12837 CASE_CFN_CLRSB:
12840 /* Always true. */
12843 CASE_CFN_SQRT:
12844 /* sqrt(-0.0) is -0.0. */
12849 CASE_CFN_ASINH:
12850 CASE_CFN_ATAN:
12851 CASE_CFN_ATANH:
12852 CASE_CFN_CBRT:
12853 CASE_CFN_CEIL:
12854 CASE_CFN_ERF:
12855 CASE_CFN_EXPM1:
12856 CASE_CFN_FLOOR:
12857 CASE_CFN_FMOD:
12858 CASE_CFN_FREXP:
12859 CASE_CFN_ICEIL:
12860 CASE_CFN_IFLOOR:
12861 CASE_CFN_IRINT:
12862 CASE_CFN_IROUND:
12863 CASE_CFN_LCEIL:
12864 CASE_CFN_LDEXP:
12865 CASE_CFN_LFLOOR:
12866 CASE_CFN_LLCEIL:
12867 CASE_CFN_LLFLOOR:
12868 CASE_CFN_LLRINT:
12869 CASE_CFN_LLROUND:
12870 CASE_CFN_LRINT:
12871 CASE_CFN_LROUND:
12872 CASE_CFN_MODF:
12873 CASE_CFN_NEARBYINT:
12874 CASE_CFN_RINT:
12875 CASE_CFN_ROUND:
12876 CASE_CFN_SCALB:
12877 CASE_CFN_SCALBLN:
12878 CASE_CFN_SCALBN:
12879 CASE_CFN_SIGNBIT:
12880 CASE_CFN_SIGNIFICAND:
12881 CASE_CFN_SINH:
12882 CASE_CFN_TANH:
12883 CASE_CFN_TRUNC:
12884 /* True if the 1st argument is nonnegative. */
12887 CASE_CFN_FMAX:
12888 /* True if the 1st OR 2nd arguments are nonnegative. */
12891 CASE_CFN_FMIN:
12892 /* True if the 1st AND 2nd arguments are nonnegative. */
12895 CASE_CFN_COPYSIGN:
12896 /* True if the 2nd argument is nonnegative. */
12899 CASE_CFN_POWI:
12900 /* True if the 1st argument is nonnegative or the second
12901 argument is an even integer. */
12907 CASE_CFN_POW:
12908 /* True if the 1st argument is nonnegative or the second
12909 argument is an even integer valued real. */
12911 {
12912 REAL_VALUE_TYPE c;
12913 HOST_WIDE_INT n;
12918 {
12919 REAL_VALUE_TYPE cint;
12923 }
12924 }
12929 }
12931 }
12933 /* Return true if T is known to be non-negative. If the return
12934 value is based on the assumption that signed overflow is undefined,
12935 set *STRICT_OVERFLOW_P to true; otherwise, don't change
12936 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
12938 static bool
12940 {
12946 {
12948 {
12952 /* If the initializer is non-void, then it's a normal expression
12953 that will be assigned to the slot. */
12957 /* Otherwise, the initializer sets the slot in some way. One common
12958 way is an assignment statement at the end of the initializer. */
12960 {
12968 else
12970 }
12976 }
12979 {
12985 arg0,
12986 arg1,
12988 }
13001 }
13002 }
13004 #undef RECURSE
13005 #undef tree_expr_nonnegative_warnv_p
13007 /* Return true if T is known to be non-negative. If the return
13008 value is based on the assumption that signed overflow is undefined,
13009 set *STRICT_OVERFLOW_P to true; otherwise, don't change
13010 *STRICT_OVERFLOW_P. DEPTH is the current nesting depth of the query. */
13012 bool
13014 {
13021 {
13043 }
13046 {
13072 }
13073 }
13075 /* Return true if `t' is known to be non-negative. Handle warnings
13076 about undefined signed overflow. */
13078 bool
13080 {
13087 "determining that expression is always "
13089 WARN_STRICT_OVERFLOW_MISC);
13091 }
13094 /* Return true when (CODE OP0) is an address and is known to be nonzero.
13095 For floating point we further ensure that T is not denormal.
13096 Similar logic is present in nonzero_address in rtlanal.h.
13098 If the return value is based on the assumption that signed overflow
13099 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13100 change *STRICT_OVERFLOW_P. */
13102 bool
13105 {
13107 {
13110 strict_overflow_p);
13113 {
13119 strict_overflow_p));
13120 }
13125 strict_overflow_p);
13129 }
13132 }
13134 /* Return true when (CODE OP0 OP1) is an address and is known to be nonzero.
13135 For floating point we further ensure that T is not denormal.
13136 Similar logic is present in nonzero_address in rtlanal.h.
13138 If the return value is based on the assumption that signed overflow
13139 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13140 change *STRICT_OVERFLOW_P. */
13142 bool
13144 tree type,
13145 tree op0,
13147 {
13150 {
13154 {
13155 /* With the presence of negative values it is hard
13156 to say something. */
13163 /* One of operands must be positive and the other non-negative. */
13164 /* We don't set *STRICT_OVERFLOW_P here: even if this value
13165 overflows, on a twos-complement machine the sum of two
13166 nonnegative numbers can never be zero. */
13168 strict_overflow_p)
13170 strict_overflow_p));
13171 }
13176 {
13178 strict_overflow_p)
13180 strict_overflow_p))
13181 {
13184 }
13185 }
13194 {
13197 }
13204 {
13208 /* When both operands are nonzero, then MAX must be too. */
13210 strict_overflow_p))
13213 /* MAX where operand 0 is positive is positive. */
13215 strict_overflow_p);
13216 }
13217 /* MAX where operand 1 is positive is positive. */
13222 {
13226 }
13231 strict_overflow_p)
13233 strict_overflow_p));
13237 }
13240 }
13242 /* Return true when T is an address and is known to be nonzero.
13243 For floating point we further ensure that T is not denormal.
13244 Similar logic is present in nonzero_address in rtlanal.h.
13246 If the return value is based on the assumption that signed overflow
13247 is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
13248 change *STRICT_OVERFLOW_P. */
13250 bool
13252 {
13255 {
13260 {
13272 /* For objects in symbol table check if we know they are non-zero.
13273 Don't do anything for variables and functions before symtab is built;
13274 it is quite possible that they will be declared weak later. */
13279 /* Function local objects are never NULL. */
13286 /* Constants are never weak. */
13291 }
13299 {
13303 }
13308 }
13310 }
13312 #define integer_valued_real_p(X) \
13315 #define RECURSE(X) \
13316 ((integer_valued_real_p) (X, depth + 1))
13318 /* Return true if the floating point result of (CODE OP0) has an
13319 integer value. We also allow +Inf, -Inf and NaN to be considered
13320 integer values. Return false for signaling NaN.
13322 DEPTH is the current nesting depth of the query. */
13324 bool
13326 {
13328 {
13335 CASE_CONVERT:
13336 {
13343 }
13347 }
13349 }
13351 /* Return true if the floating point result of (CODE OP0 OP1) has an
13352 integer value. We also allow +Inf, -Inf and NaN to be considered
13353 integer values. Return false for signaling NaN.
13355 DEPTH is the current nesting depth of the query. */
13357 bool
13359 {
13361 {
13371 }
13373 }
13375 /* Return true if the floating point result of calling FNDECL with arguments
13376 ARG0 and ARG1 has an integer value. We also allow +Inf, -Inf and NaN to be
13377 considered integer values. Return false for signaling NaN. If FNDECL
13378 takes fewer than 2 arguments, the remaining ARGn are null.
13380 DEPTH is the current nesting depth of the query. */
13382 bool
13384 {
13386 {
13387 CASE_CFN_CEIL:
13388 CASE_CFN_FLOOR:
13389 CASE_CFN_NEARBYINT:
13390 CASE_CFN_RINT:
13391 CASE_CFN_ROUND:
13392 CASE_CFN_TRUNC:
13395 CASE_CFN_FMIN:
13396 CASE_CFN_FMAX:
13401 }
13403 }
13405 /* Return true if the floating point expression T (a GIMPLE_SINGLE_RHS)
13406 has an integer value. We also allow +Inf, -Inf and NaN to be
13407 considered integer values. Return false for signaling NaN.
13409 DEPTH is the current nesting depth of the query. */
13411 bool
13413 {
13415 {
13423 /* Limit the depth of recursion to avoid quadratic behavior.
13424 This is expected to catch almost all occurrences in practice.
13425 If this code misses important cases that unbounded recursion
13426 would not, passes that need this information could be revised
13427 to provide it through dataflow propagation. */
13431 depth));
13435 }
13437 }
13439 /* Return true if the floating point expression T (a GIMPLE_INVALID_RHS)
13440 has an integer value. We also allow +Inf, -Inf and NaN to be
13441 considered integer values. Return false for signaling NaN.
13443 DEPTH is the current nesting depth of the query. */
13445 static bool
13447 {
13449 {
13460 }
13462 }
13464 #undef RECURSE
13465 #undef integer_valued_real_p
13467 /* Return true if the floating point expression T has an integer value.
13468 We also allow +Inf, -Inf and NaN to be considered integer values.
13469 Return false for signaling NaN.
13471 DEPTH is the current nesting depth of the query. */
13473 bool
13475 {
13481 {
13497 }
13500 {
13506 {
13515 }
13519 }
13520 }
13522 /* Given the components of a binary expression CODE, TYPE, OP0 and OP1,
13523 attempt to fold the expression to a constant without modifying TYPE,
13524 OP0 or OP1.
13526 If the expression could be simplified to a constant, then return
13527 the constant. If the expression would not be simplified to a
13528 constant, then return NULL_TREE. */
13530 tree
13532 {
13535 }
13537 /* Given the components of a unary expression CODE, TYPE and OP0,
13538 attempt to fold the expression to a constant without modifying
13539 TYPE or OP0.
13541 If the expression could be simplified to a constant, then return
13542 the constant. If the expression would not be simplified to a
13543 constant, then return NULL_TREE. */
13545 tree
13547 {
13550 }
13552 /* If EXP represents referencing an element in a constant string
13553 (either via pointer arithmetic or array indexing), return the
13554 tree representing the value accessed, otherwise return NULL. */
13556 tree
13558 {
13562 {
13564 tree index;
13565 tree string;
13570 else
13571 {
13575 /* Optimize the special-case of a zero lower bound.
13577 We convert the low_bound to sizetype to avoid some problems
13578 with constant folding. (E.g. suppose the lower bound is 1,
13579 and its mode is QI. Without the conversion,l (ARRAY
13580 +(INDEX-(unsigned char)1)) becomes ((ARRAY+(-(unsigned char)1))
13581 +INDEX), which becomes (ARRAY+255+INDEX). Oops!) */
13587 }
13600 }
13602 }
13604 /* Return the tree for neg (ARG0) when ARG0 is known to be either
13605 an integer constant, real, or fixed-point constant.
13607 TYPE is the type of the result. */
13609 static tree
13611 {
13615 {
13617 {
13624 }
13631 {
13632 FIXED_VALUE_TYPE f;
13637 /* Propagate overflow flags. */
13641 }
13645 }
13648 }
13650 /* Return the tree for abs (ARG0) when ARG0 is known to be either
13651 an integer constant or real constant.
13653 TYPE is the type of the result. */
13655 tree
13657 {
13661 {
13663 {
13664 /* If the value is unsigned or non-negative, then the absolute value
13665 is the same as the ordinary value. */
13669 /* If the value is negative, then the absolute value is
13670 its negation. */
13671 else
13672 {
13677 }
13678 }
13684 else
13690 }
13693 }
13695 /* Return the tree for not (ARG0) when ARG0 is known to be an integer
13696 constant. TYPE is the type of the result. */
13698 static tree
13700 {
13704 }
13706 /* Given CODE, a relational operator, the target type, TYPE and two
13707 constant operands OP0 and OP1, return the result of the
13708 relational operation. If the result is not a compile time
13709 constant, then return NULL_TREE. */
13711 static tree
13713 {
13716 /* From here on, the only cases we handle are when the result is
13717 known to be a constant. */
13720 {
13724 /* Handle the cases where either operand is a NaN. */
13726 {
13728 {
13756 }
13759 }
13762 }
13765 {
13769 }
13771 /* Handle equality/inequality of complex constants. */
13773 {
13784 else
13786 }
13789 {
13791 {
13792 /* Have vector comparison with scalar boolean result. */
13796 {
13804 }
13806 }
13813 {
13825 }
13828 }
13830 /* From here on we only handle LT, LE, GT, GE, EQ and NE.
13832 To compute GT, swap the arguments and do LT.
13833 To compute GE, do LT and invert the result.
13834 To compute LE, swap the arguments, do LT and invert the result.
13835 To compute NE, do EQ and invert the result.
13837 Therefore, the code below must handle only EQ and LT. */
13840 {
13843 }
13845 /* Note that it is safe to invert for real values here because we
13846 have already handled the one case that it matters. */
13850 {
13853 }
13855 /* Compute a result for LT or EQ if args permit;
13856 Otherwise return T. */
13858 {
13861 else
13863 }
13864 else
13870 }
13872 /* If necessary, return a CLEANUP_POINT_EXPR for EXPR with the
13873 indicated TYPE. If no CLEANUP_POINT_EXPR is necessary, return EXPR
13874 itself. */
13876 tree
13878 {
13879 /* If the expression does not have side effects then we don't have to wrap
13880 it with a cleanup point expression. */
13884 /* If the expression is a return, check to see if the expression inside the
13885 return has no side effects or the right hand side of the modify expression
13886 inside the return. If either don't have side effects set we don't need to
13887 wrap the expression in a cleanup point expression. Note we don't check the
13888 left hand side of the modify because it should always be a return decl. */
13890 {
13897 }
13900 }
13902 /* Given a pointer value OP0 and a type TYPE, return a simplified version
13903 of an indirection through OP0, or NULL_TREE if no simplification is
13904 possible. */
13906 tree
13908 {
13910 tree subtype;
13918 {
13921 /* *&CONST_DECL -> to the value of the const decl. */
13924 /* *&p => p; make sure to handle *&"str"[cst] here. */
13926 {
13930 else
13932 }
13933 /* *(foo *)&fooarray => fooarray[0] */
13936 && (!in_gimple_form
13938 {
13948 }
13949 /* *(foo *)&complexfoo => __real__ complexfoo */
13953 /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */
13956 {
13960 }
13961 }
13965 {
13971 {
13972 tree op00type;
13976 /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */
13979 {
13981 unsigned HOST_WIDE_INT max_offset
13986 {
13993 }
13994 }
13995 /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */
13998 {
14002 }
14003 /* ((foo *)&fooarray)[1] => fooarray[1] */
14006 {
14016 }
14017 }
14018 }
14020 /* *(foo *)fooarrptr => (*fooarrptr)[0] */
14023 && (!in_gimple_form
14025 {
14026 tree type_domain;
14036 NULL_TREE);
14037 }
14040 }
14042 /* Builds an expression for an indirection through T, simplifying some
14043 cases. */
14045 tree
14047 {
14055 }
14057 /* Given an INDIRECT_REF T, return either T or a simplified version. */
14059 tree
14061 {
14066 else
14068 }
14070 /* Strip non-trapping, non-side-effecting tree nodes from an expression
14071 whose result is ignored. The type of the returned tree need not be
14072 the same as the original expression. */
14074 tree
14076 {
14082 {
14093 else
14099 {
14115 }
14120 }
14121 }
14123 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
14125 tree
14127 {
14133 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14134 have to do anything. Only do this when we are not given a const,
14135 because in that case, this check is more expensive than just
14136 doing it. */
14138 {
14143 }
14145 /* If divisor is a power of two, simplify this to bit manipulation. */
14147 {
14149 {
14163 }
14164 else
14165 {
14166 tree t;
14172 }
14173 }
14174 else
14175 {
14180 }
14183 }
14185 /* Likewise, but round down. */
14187 tree
14189 {
14196 /* See if VALUE is already a multiple of DIVISOR. If so, we don't
14197 have to do anything. Only do this when we are not given a const,
14198 because in that case, this check is more expensive than just
14199 doing it. */
14201 {
14206 }
14208 /* If divisor is a power of two, simplify this to bit manipulation. */
14210 {
14211 tree t;
14215 }
14216 else
14217 {
14222 }
14225 }
14227 /* Returns the pointer to the base of the object addressed by EXP and
14228 extracts the information about the offset of the access, storing it
14229 to PBITPOS and POFFSET. */
14231 static tree
14234 {
14235 tree core;
14236 machine_mode mode;
14238 HOST_WIDE_INT bitsize;
14242 {
14247 }
14248 else
14249 {
14253 }
14256 }
14258 /* Returns true if addresses of E1 and E2 differ by a constant, false
14259 otherwise. If they do, E1 - E2 is stored in *DIFF. */
14261 bool
14263 {
14277 {
14287 }
14289 {
14290 /* If only one of the offsets is non-constant, the difference cannot
14291 be a constant. */
14293 }
14294 else
14299 }
14301 /* Return OFF converted to a pointer offset type suitable as offset for
14302 POINTER_PLUS_EXPR. Use location LOC for this conversion. */
14303 tree
14305 {
14307 }
14309 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14310 tree
14312 {
14315 }
14317 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF. */
14318 tree
14320 {
14323 }
14325 /* Return a char pointer for a C string if it is a string constant
14326 or sum of string constant and integer constant. We only support
14327 string constants properly terminated with '\0' character.
14328 If STRLEN is a valid pointer, length (including terminating character)
14329 of returned string is stored to the argument. */
14333 {
14334 tree offset_node;
14345 {
14348 else
14350 }
14355 /* Support only properly null-terminated strings. */
14364 }
14366 #if CHECKING_P
14370 /* Helper functions for writing tests of folding trees. */
14372 /* Verify that the binary op (LHS CODE RHS) folds to CONSTANT. */
14374 static void
14376 tree constant)
14377 {
14379 }
14381 /* Verify that the binary op (LHS CODE RHS) folds to an NON_LVALUE_EXPR
14382 wrapping WRAPPED_EXPR. */
14384 static void
14386 tree wrapped_expr)
14387 {
14392 }
14394 /* Verify that various arithmetic binary operations are folded
14395 correctly. */
14397 static void
14399 {
14405 /* Addition. */
14406 /* 1 <-- (0 + 1) */
14408 one);
14410 one);
14412 /* (nonlvalue)x <-- (x + 0) */
14414 x);
14416 /* Subtraction. */
14417 /* 0 <-- (x - x) */
14419 zero);
14421 x);
14423 /* Multiplication. */
14424 /* 0 <-- (x * 0) */
14426 zero);
14428 /* (nonlvalue)x <-- (x * 1) */
14430 x);
14431 }
14433 /* Verify that various binary operations on vectors are folded
14434 correctly. */
14436 static void
14438 {
14444 /* Verify equality tests that return a scalar boolean result. */
14450 }
14452 /* Run all of the selftests within this file. */
14454 void
14456 {
14459 }